WO2022243512A1 - Naloxone for treating proteinopathies of the central nervous system - Google Patents

Abstract

The present invention relates to the field of medicine. In particular, it relates to naloxone and its use in the treatment of proteinopathies of the central nervous system, in particular of the animal or human prion disease. The invention also relates to a pharmaceutical combination of naloxone and tenoxicam and its use in the treatment of proteinopathy of the CNS.

Description

NALOXONE FOR TREATING PROTEINOPATHIES OF THE CENTRAL

NERVOUS SYSTEM

TECHNICAL FIELD

The present invention relates to the field of medicine. In particular, it relates to naloxone and its use in the treatment of proteinopathies of the central nervous system.

TECHNICAL BACKGROUND

Even though great efforts have been dedicated to research for many years, the precise molecular mechanisms that lead to neurodegeneration in pathologies such as Alzheimer's, Parkinson's, Huntington's or Creutzfeldt-Jakob's diseases are far from being elucidated. In general, these disorders share a common mechanism of aberrant folding of distinct proteins that, upon misfolding, become more prone to aggregation, and, in turn, may become highly neurotoxic. This mechanism is often referred to as "prion paradigm".

Prion paradigm has emerged as a unifying molecular principle for the pathogenesis of many age-related neurodegenerative diseases. This paradigm holds that a fundamental cause of specific disorders is the misfolding and seeded aggregation of certain proteins. The concept arose from the discovery that devastating brain diseases called spongiform encephalopathies are transmissible to new hosts by agents consisting solely of a misfolded protein, now known as the prion protein. Accordingly, “prion” was defined as a “proteinaceous infectious particle.” As the concept has expanded to include other diseases, many of which are not infectious by any conventional definition, the designation of prions as infectious agents has become problematic. The physiological cellular prion protein (PrP^c) is a membrane-bound protein predominantly expressed in the nervous tissue, where it probably plays a role in neuronal development and function. When in an aberrant misfolded state, the prion protein is named PrP^Sc and is able to recruit and convert PrP^c, into misfolded isoform. Prions thus act as corruptive templates (seeds) that initiate a chain-reaction of PrP misfolding and aggregation (seeding property). As prions grow, fragment and spread from on neuron to another (spreading property), they cause neuronal loss, thereby perturbing the function of the nervous system and ultimately causing the death of the affected individual.

The misfolding and aggregation of specific proteins within nervous system occur also in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Lewy body dementia (LBD), Huntington's disease (HD) and frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), amyotrophic lateral sclerosis (SLA) now referred as prion-like disorders. In these disorders, Tau (AD, PSP, DCB, FTD), beta-amyloid peptide (AD), TDP-43 (SLA) and alpha-synuclein (PD, DLB) are the most commonly misfolded proteins, which form highly ordered filamentous inclusions with a core region of cross-beta- conformation. These proteins have also been named ' 'prionoids ', “propagons” , “pseudoprions” , “ proteopathic seeds ” indicating that they exhibit prion-like properties. The prion properties of prionoids (two structural isoforms, ability of assemblies of pathological isoforms to induce the seeded aggregation of the normal isoform and to spread from one cell to another) has been put forward to explain the progressive dissemination of the lesions within the central nervous system (CNS), which is associated with clinical worsening, that follows a staging that is specific of each proteinopathy.

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a class of fatal infectious neurodegenerative disorders whose pathogenesis mechanisms are not fully understood. Prion diseases are characterized by neuronal vacuolation (spongiform changes of the neuropile) associated with gliosis and prion protein deposits. So far, no effective therapeutic targets have been identified.

The only known specific molecular marker of prion diseases is the abnormal prion protein isoform of the host encoded prion protein, which accumulates in the brain of infected subjects and forms infectious prion particles. Although this transmissible agent lacks a specific nucleic acid component, several prion strains have been isolated. They are characterized, notably, by differences in disease duration, PrP^Sc distribution patterns, and brain lesions profiles at the terminal stage of the disease.

This group of fatal diseases is highly heterogeneous and includes, in humans, sporadic, infectious and genetic forms among which a limited number of human prion strains have been identified so far. Familial Creutzfeldt-Jakob disease (CJD) due to the E200K mutation of the PrP coding gene ( PRNP ) is the most common form of inherited prion disease. The phenotype resembles that of sporadic Creutzfeldt-Jakob disease at both the clinical and neuropathological levels with a median disease duration from first symptoms to death of 4 months. Recent evidence supports a near 100% penetrance of the E200K variant.

Few anti-prion compounds such as quinacrine and pentosan polysulfate showed a therapeutic activity in vivo and in vitro , but none was proven effective in humans. A major issue in therapeutic research is the variability of the anti-prion effect between strains and the necessity to identify drugs that are effective towards human prions. In addition, existing in vivo models of infectious or inherited forms do not allow high-throughput approaches that may facilitate the discovery of novel anti-prion compounds targeting human PrP pathological assemblies or their effects on neuronal function and survival. It was thus of high interest to use a reliable in vivo experimental model allowing the screening of medium to large size libraries of compounds against human prion replication. Here, a genetic model in the nematode C. elegans was exploited. Nematodes, which are devoid of any PrP homolog, were engineered to express the human PrP with the E200K mutation in the mecanosensitive neuronal system. This model has a fully described cell lineage and well identified neuronal networks with a precisely known functional connectivity of each of its 302 neurons (White et ah, 1986). In addition, most of C. elegans genes have their counterparts in humans (Bargmann, 1998).

By screening numerous known drugs according to the method using C. elegans , Naloxone was selected among the screened drugs as one of the most promising active compounds. Naloxone is able to efficiently cross the blood brain barrier and to penetrate the central nervous system. Biological tests detailed below have demonstrated that Naloxone has the following effects: i) neuroprotective, ii) restaure neuronal functionality, iii) modify intraneuronal PrP aggregates, and iv) reduce the accumulation of PrP^res (the N-terminal truncated PK-resistant fragment of PrP^Sc).

Based on these properties, Naloxone appears to be a potent candidate for the treatment of prion disease and more generally for the treatment of proteinopathies of the CNS.

It is therefore an object of the present invention to provide a medicament having activity against proteinopathies of the CNS in a human or animal subject.

It is another object of the present invention to provide a medicament which is effective from an early stage of a proteinopathy of the CNS, such as a prion disease, to a later stage thereof. Further, an object of the present invention is to provide a medicament which is effective in preventing or delaying the onset of a proteinopathy of the CNS and/or progression of the disease.

A yet further object of the present invention is to provide a medicament which is effective in inhibiting the progression of already established proteinopathy of the CNS. SUMMARY OF THE INVENTION

The present invention relates to naloxone for use in the treatment of a proteinopathy of the CNS in a subject in need thereof.

The invention also provides a pharmaceutical composition for use in the treatment of a proteinopathy of the CNS in a subject in need thereof. The pharmaceutical composition contains naloxone in combination with a pharmaceutically acceptable carrier, excipient and/or diluent. The invention also relates to a method of treatment of a proteinopathy of the CNS in a subject in need thereof, comprising administration to said subject of an effective amount of naloxone or pharmaceutical composition comprising the same.

Finally, the invention deals with a use of naloxone in the manufacture of a medicament for treating a proteinopathy of the CNS in a subject.

DESCRIPTION OF THE FIGURES

Figure n°l. PrPwt and RGRE2OOK animals were incubated with various compounds (// = 320) at different concentration (1, 10 and 100 mM) during 3 days. Number of GFP-tagged PLM neurons were analyzed with an automated analyzer system. Naloxone hydrochloride compounds inducing a significant increase of PLMs survival in RGRE2OOK (B) whereas no deleterious effect was observed in PrPwt animals (A). Data are means ± s.e.m. of three independent experiments, n = 8 animals per condition and per experiment corresponding to a total of // = 24,192 animals. Statistical significance was calculated with a two-tailed unpaired /-test for the RGRE2OOK animals treated with compounds versus the control untreated RGRE2OOK line; *p < 0.05; **p < 0.01; ***/? < 0.005; n.s., not significant.

Figure n°2. PrPwt and RGRE2OOK animals were incubated in presence of a 1, 10 and 100 pM concentration of naloxone hydrochloride during 3 days. Quantification of the PLMs neurons n = 50 worms per condition and per experiment. Naloxone hydrochloride restores survival and function of mechanosensitive neurons in RGRE2OOK line. Data are means ± s.e.m. of three independent experiments. Statistical significance was calculated with a one-way ANOVA followed by a Dunnetfs multiple comparisons test for all the experimental condition versus the untreated RGRE2OOK line; **p < 0.01 and ****p < 0.001. Figure n°3. PrPwt and RGRE2OOK lines were incubated in presence of naloxone hydrochloride treatment (10 mM) during 3 days. (A) Percentage of animals showing a severe locomotor defect in liquid media. Data are means ± s.e.m. of three independent experiments, n = 25 animals per experiment. (B) Percentage of touch test responders scored in young adult animals. Data are means ± s.e.m. of three independent experiments, n = 25 animals per experiment. Statistical significance was calculated with a one-way ANOVA followed by a Dunnetf s multiple comparisons test versus the control (untreated) RGRE2OOK line; *p < 0.05 and ****p < 0.0001; n.s., not significant.

Figure n°4. RGRE2OOK young adults after 3 days incubation with the naloxone hydrochloride (10 mM) were immunolabeled with anti-PrP monoclonal antibody Sha-31. Mean volume of intracellular PrP aggregates. PrP-immunopositive aggregates with a volume ranging from 1 to 30. 10^'3 pm³. Data are means ± s.e.m. of three independent experiments per compound, n = 10 PrP-immunopositive objects per condition and per experiment. Statistical significance was calculated with a two-tailed unpaired /-test for each RGRE2OOK animals treated with one compound versus the untreated RGRE2OOK control; *p < 0.05.

Figure n°5. Effect of treatments on PrP^res detection in RGRE2OOK animals. Animal’s homogenates treated with naloxone (10 pM) were analyzed by western-blot using the anti-prion monoclonal antibody 3F4 (l/1000^e) and after treatment with PK, the PrP^res signal was quantified. Data are means ± s.e.m. of three independent experiments per compound, statistical significance was calculated with a two-tailed unpaired /-test for each RGRE2OOK animals treated with one compound versus the untreated RGRE2OOK control line, **p < 0.01

0.0001.

Figure n°6. Transgenic animals expressing the GFP fluorescent marker in the mechanosensitive neuronal system in absence (Control^GFP; PrP ) or in presence of human prion protein (PrPwt and RGRE2OOK) were incubated with tenoxicam and naloxone alone or in association at 0.25 pM and 0.5 pM and, chronically during 3 days. When associated at such concentration, which is ineffective in monotherapy, an effect was observed that restored the mechanosensitive neuronal functionality and the number of PrP expressing mechanosensitive neurons. (A) Percentage of animals showing a severe locomotor defect in liquid media. Data are means ± s.e.m. of three independent experiments, n = 50 animals per experiment. (B) Percentage of touch test responders scored in young adult animals. Data are means ± s.e.m. of three independent experiments, n = 50 animals per experiment. (C) Quantification of the PLMs neurons. n = 50 worms per condition and per experiment. Statistical significance was calculated with a one-way ANOVA followed by a Dunnetf s multiple comparisons test versus the control (untreated) RGRE2OOK line; *p < 0.05, **p < 0.01, ***p < 0.001 and ****p < 0.0001; n.s., not significant.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

As used herein, the terms “treatment”, “treat” or “treating” refer to any act intended to ameliorate the health status of patients such as therapy, prevention, prophylaxis and retardation of a disease. In certain embodiments, such terms refer to the amelioration or eradication of the disease, or symptoms associated with it. In other embodiments, this term refers to minimizing or reducing the spread or worsening of the disease, resulting from the administration of one or more therapeutic agents to a subject with such a disease.

As used herein, the term "affect" refers to either blocking or slow downing the pathological processes associated with prion or prion-like disorders.

As used herein, the terms “subject”, “individual” or “patient” are interchangeable and refer to an animal, preferably to a mammal, even more preferably to a human, including adult, child, newborn and human at the prenatal stage. However, the term "subject" can also refer to non human animals, in particular mammals such as dogs, cats, horses, cows, pigs, sheep and non human primates, among others. In accordance to the present invention, the subject can be affected by a prion or prion-like disease, exhibiting symptoms which may vary from mild to severe. Alternatively, according to the present invention, the subject can be at risk of developing a prion or prion-like disease.

The terms “quantity,” “amount,” and “dose” are used interchangeably herein and may refer to an absolute quantification of a molecule.

As used herein, the terms "active principle", "active ingredient" and "active pharmaceutical ingredient" are equivalent and refers to a component of a pharmaceutical composition or a medicament having a therapeutic effect.

As used herein, the term “therapeutic effect” refers to an effect induced by an active ingredient, or a pharmaceutical composition according to the invention, capable to prevent or to delay the appearance of a disease, or to cure or to attenuate the effects of a disease.

As used herein, the term “effective amount” refers to a quantity of naloxone or of a pharmaceutical composition comprising the same which prevents, removes or reduces the deleterious effects of the disease. It is obvious that the quantity to be administered can be adapted by the man skilled in the art according to the subject to be treated, to the nature of the disease, etc. In particular, doses and regimen of administration may be function of the nature, of the stage and of the severity of the disease to be treated, as well as of the weight, the age and the global health of the subject to be treated, as well as of the judgment of the doctor.

As used herein, the term "excipient” or “carrier" or “diluent” refers to any ingredient except active ingredients that is present in a pharmaceutical composition. Its addition may be aimed to confer a particular consistency or other physical or gustative properties to the final product. An excipient or pharmaceutically acceptable carrier must be devoid of any interaction, in particular chemical, with the active ingredients.

According to the invention, the term naloxone includes naloxone base, or a pharmaceutically acceptable salt or solvate (such as hydrate) thereof, including naloxone HC1, naloxone HC1 dihydrate, or combinations thereof. According to a particular embodiment naloxone is naloxone hydrochloride.

According to the present invention, a salt of naloxone of the invention may be, for example, an acid-addition salt of a compound of the invention, such as, an acid-addition salt with an inorganic or organic acid, for example hydrochloric, hydrobromic, sulfuric, phosphoric, nitric, perchloric, acetic, trifluoroacetic, fumaric, formic, citric, maleic, propionic, succinic, glycolic, lactic, tartaric, palmoic, malonic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, toluenesulfonic, methanesulfonic, naphthalene-2-sulfonic, benzenesulfonic hydroxynaphthoic, hydroiodic, malic, steroic, or tannic acid. A suitable pharmaceutically acceptable salt of a naloxone of the invention may also be an alkali metal salt, for example a lithium, sodium or potassium salt, an alkaline earth metal salt, for example a calcium or magnesium salt, an ammonium salt or a salt with an organic base which affords a pharmaceutically acceptable cation, for example a salt with methylamine, dimethylamine, trimethylamine, piperidine, morpholine or tris-(2-hydroxy ethyl) amine. More preferably, it refers to naloxone HC1.

A “solvate”, as used herein, refers to a complex comprising naloxone of the invention with at least one solvent, typically a solvent in which the compound of the invention is reacted or from which it is precipitated or crystallized. For example, a complex with water is known as a "hydrate". Other examples of solvents which can be found in solvates include, but are not limited to, acetone, methyl ethyl ketone, toluene, methanol, ethanol, propanol, isopropanol, benzyl alcohol, acetonitrile, tetrahydrofuran, ether, or dichloromethane. It can refer to naloxone HC1 dihydrate. The present invention also relates to a pharmaceutical composition comprising naloxone as defined herein, or a pharmaceutically acceptable salt or solvate thereof, and at least one pharmaceutically acceptable excipient, for use according to the invention.

The pharmaceutical composition can comprise naloxone, as the sole active ingredient, or is combined to at least one additional active ingredient. therapeutic uses

As illustrated by the examples, the inventors have found that naloxone has anti-aggregation properties of specific proteins associated with prion disease and more generally with proteinopathy of the CNS. It also restores neuronal functionality and/or has neuroprotective effects. In particular, naloxone modifies intraneuronal PrP aggregates, and more specifically reduces the volume of PrP aggregates, and reduces PrP^res accumulation,

Accordingly, the present invention relates to naloxone or a pharmaceutical composition as defined above for use in the treatment of a prion disease and more generally a proteinopathy of the CNS in a subject in need thereof.

According to the invention, naloxone is able to reduce the accumulation of a misfolded amyloid protein, such as PrP^Sc, and to significantly reduce neuronal dysfunction and loss, by inhibiting protein misfolding, increasing amyloid clearance and triggering neuroprotective pathways. In that context, it can be stated that naloxone has positive effects in subjects affected by diseases associated with protein misfolding in the CNS, also called herein proteinopathy of the CNS, including prion disease.

The proteinopathies of the CNS as defined above can include neurodegenerative diseases. As used herein, a “neurodegenerative disease” refers to a disease or a disorder which involves a progressive damage of the structure or function of a neuron, including the death or demyelination of the neuron. Examples of proteinopathies diseases of the CNS, more specifically brain proteinopathies, which can be treated according to the invention, include, but are not limited to:

Diseases associated with deposits of amyloid b peptides including Alzheimer’s disease, Down’s syndrome or cerebral amyloid angiopathy.

Diseases associated with tau inclusions including Alzheimer’s disease, primary age- related tauopathy, Down’s syndrome, progressive supranuclear palsy, corticobasal degeneration, amyotrophic lateral sclerosis/parkinsonism-dementia complex, anti- IgLON5 -related tauopathy, chronic traumatic encephalopathy, diffuse neurofibrillary tangles with calcification, familial British dementia, familial Danish dementia, Gerstmann-Straiissler-Scheinker disease, MAPT mutations such as P301S, P301L, G272V, Q336R, V337M and R406W, myotonic dystrophy, Niemann-Pick disease type C, non-Guamanian motor neuron disease with neurofibrillary tangles, postencephalitic parkinsonism, progressive ataxia and palatal tremor, tangle-only dementia, argyrophilic grain disease, Guadeloupean parkinsonism, globular glial tauopathy, SLC9a-related parkinsonism, Tau astrogliopathy, Pick’s disease, or frontotemporal dementia with Pick’s bodies.

Animal and human prion diseases including chronic wasting disease, bovine spongiform encephalopathy, scrapie, Creutzfeldt-Jakob disease (CJD) including sporadic CJD, inherited CJD (such as CJD due to E200K, D178N and V210I mutations within PRNP ) and infectious CJD (such as iatrogenic CJD and variant CJD), familial fatal insomnia (mutation D178N), sporadic fatal insomnia, or Gerstmann-Straiissler-Scheinker syndrome (such as disease due to P102L and A117V mutations and insertion in the octarepeat domain within PRNP).

Alpha-synucleinopathies including Parkinson's disease, Lewy body dementia, multiple system atrophy, pure autonomic dysfunction with synuclein deposition, Lewy body subtype Alzheimer's disease, essential tremor with Lewy bodies, familial parkinsonism with or without dementia, drug-induced parkinsonism with a-synuclein deposition, metabolic storage disorders such as Gaucher's disease, caused by mutations in the GBA gene and Sanfilippo syndrome, caused by mutations in the alpha-N- acetylglucosaminidase (NAGLU) gene, or parkinsonism resulting from neurotoxin exposure.

Diseases associated with polyglutamine (polyQ) expansion in multiple proteins including Huntington's disease, dentatorubral-pallidoluysian atrophy (DRPLA) and/or several types of spinocerebellar ataxias (such as SCA1, 2, 3, 6, 7 and 17).

Motor neurone diseases including amyotrophic lateral sclerosis which can be sporadic or inherited; Neurodegenerative diseases involving SOD1, TDP-43, FUS, and/or C9orf72; Frontotemporal dementia; Brain diseases associated with neuroserpin; or Brain diseases associated with progranulin.

According to particular embodiments of the invention, naloxone or a pharmaceutical composition as defined above is for use in the treatment of a proteinopathy selected from the group consisting of diseases associated with deposits of amyloid b peptides (such as Alzheimer disease), diseases associated with tau inclusions, animal and human prion diseases, alpha- synucleinopathies (such as Parkinson disease), diseases associated with polyglutamine (polyQ) expansion in multiple proteins, and motor neurone diseases, as detailed above.

According to another particular embodiment, proteinopathies of the CNS that can be treated with the compound or composition according to the invention are animal or human prion diseases, more particularly selected from chronic wasting disease, bovine spongiform encephalopathy, scrapie, Creutzfeldt- Jakob disease (CJD), including sporadic CJD, inherited CJD and infectious CJD, familial fatal insomnia, sporadic fatal insomnia, and Gerstmann- Stradssler-Scheinker syndrome. They are more specifically human prion diseases such as Creutzfeldt- Jakob disease (CJD), including sporadic CJD, inherited CJD and infectious CJD, familial fatal insomnia, sporadic fatal insomnia, or Gerstmann-Straiissler-Scheinker syndrome.

According to another particular embodiment, the prion disease that can be treated with the compound or composition according to the invention is Creutzfeldt-Jakob's disease.

According to another particular embodiment, the diseases that can be treated with the compound or composition according to the invention are selected from Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and frontotemporal dementia (FTD). The treatment of the invention can more specifically be implemented at an early stage of a proteinopathy or at a later stage thereof.

The treatment of the invention allows to have a neuroprotective effect, or to restore neuronal functionality. It also allows to modify intraneuronal PrP aggregates, and/or to reduce amyloid accumulation.

The invention further relates to a method of treatment of a proteinopathy of the CNS in a subject in need thereof, comprising administration to said subject of an effective amount of naloxone or pharmaceutical composition comprising the same, said disease being as specified above.

In addition, the present invention relates to a method for treating a proteinopathy of the CNS, in a subject, wherein a therapeutically effective amount of naloxone, is administered to said subject suffering of said disease, more specifically said subject being at an early stage of a proteinopathy or at a later stage thereof.

The invention also relates to the use of naloxone, for the manufacture of a medicine for the treatment of a proteinopathy of the CNS, preferably a disease as detailed above.

The subject according to the invention is an animal, preferably a mammal, even more preferably a human. However, the term "subject" can also refer to non-human animals, in particular laboratory, domestic, wild or farm animals. For instance, the non-human animal may be a mammal (e.g. dogs, cats, horses, cows, pigs, sheep, donkeys, rabbits, rats, mice, guinea pigs and non-human primates), that are in need of treatment.

The human subject according to the invention may be a human at the prenatal stage, a new born, a child, an infant, an adolescent or an adult, in particular an adult of at least 40 years old, preferably an adult of at least 50 years old, still more preferably an adult of at least 60 years old, even more preferably an adult of at least 70 years old.

In a preferred embodiment, the subject has been diagnosed with a disease. Preferably, the subject has been diagnosed with a proteinopathy of the CNS.

Diagnostic methods of these diseases are well known by the man skilled in the art. The compound or the pharmaceutical composition of the present invention may be administered by any conventional route of administration. In particular, said compound or pharmaceutical composition can be administered by a topical, enteral, oral, parenteral, intranasal, intravenous, intra-arterial, intramuscular, subcutaneous or intraocular administration and the like. According to a particular embodiment, naloxone or a pharmaceutical composition comprising naloxone is administered by injection.

In particular, the compound or the pharmaceutical composition of the invention can be formulated for a topical, enteral, oral, parenteral, intranasal, intravenous, intra-arterial, intramuscular, epidural, intrathecal, intraventricular, percutaneous, subcutaneous or intraocular administration and the like.

Preferably, the compound of the invention or the pharmaceutical composition of the invention is administered by enteral or parenteral route of administration. When administered parenterally, the compound of the invention or the pharmaceutical composition of the invention is preferably administered by intravenous route of administration. When administered enterally, the compound of the invention or the pharmaceutical composition of the invention is preferably administered by rectal route of administration.

The pharmaceutical composition comprising the molecule is formulated in accordance with standard pharmaceutical practice (Lippincott Williams & Wilkins, 2000) known by a person skilled in the art.

For oral administration, the composition can be formulated into conventional oral dosage forms such as tablets, capsules, powders, granules and liquid preparations such as syrups, elixirs, and concentrated drops. Nontoxic solid carriers or diluents may be used which include, for example, pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, talcum, cellulose, glucose, sucrose, magnesium, carbonate, and the like. For compressed tablets, binders, which are agents which impart cohesive qualities to powdered materials, are also necessary. For example, starch, gelatin, sugars such as lactose or dextrose, and natural or synthetic gums can be used as binders. Disintegrants are also necessary in the tablets to facilitate break-up of the tablet. Disintegrants include starches, clays, celluloses, algins, gums and crosslinked polymers. Moreover, lubricants and glidants are also included in the tablets to prevent adhesion to the tablet material to surfaces in the manufacturing process and to improve the flow characteristics of the powder material during manufacture. Colloidal silicon dioxide is most commonly used as a glidant and compounds such as talc or stearic acids are most commonly used as lubricants. For transdermal administration, the composition can be formulated into ointment, cream or gel form and appropriate penetrants or detergents could be used to facilitate permeation, such as dimethyl sulfoxide, dimethyl acetamide and dimethylformamide.

For transmucosal administration, nasal sprays, rectal or vaginal suppositories can be used. The active compound can be incorporated into any of the known suppository bases by methods known in the art. Examples of such bases include cocoa butter, polyethylene glycols (carbowaxes), polyethylene sorbitan monostearate, and mixtures of these with other compatible materials to modify the melting point or dissolution rate.

Pharmaceutical compositions of the invention may be formulated to release the active drug substantially immediately upon administration or at any predetermined time or time period after administration.

Preferably, the treatment with the compound of the invention or the pharmaceutical composition of the invention start no longer than a month, preferably no longer than a week, after the diagnosis of the disease. In a most preferred embodiment, the treatment starts the day of the diagnosis.

The compound of the invention or the pharmaceutical composition of the invention may be administered as a single dose or in multiple doses.

Preferably, the treatment is administered regularly, preferably between every day and every month, more preferably between every day and every two weeks, more preferably between every day and every week, even more preferably the treatment is administered every day. In a particular embodiment, the treatment is administered several times a day, preferably 2 or 3 times a day, even more preferably 3 times a day.

The duration of treatment with the compound of the invention or the pharmaceutical composition of the invention is preferably comprised between 1 day and 20 weeks, more preferably between 1 day and 10 weeks, still more preferably between 1 day and 4 weeks, even more preferably between 1 day and 2 weeks. In a particular embodiment, the duration of the treatment is of about 1 week. Alternatively, the treatment may last as long as the disease persists.

The amount of compound of the invention or of pharmaceutical composition of the invention to be administered has to be determined by standard procedure well known by those of ordinary skills in the art. Physiological data of the patient (e.g. age, size, and weight) and the routes of administration have to be taken into account to determine the appropriate dosage, so as a therapeutically effective amount will be administered to the patient. In a preferred embodiment, the total compound dose for each administration of the compound of the invention or of the pharmaceutical composition of the invention is comprised between 0.00001 and 1 g, preferably between 0.01 and 10 mg.

The form of the pharmaceutical compositions, the route of administration and the dose of administration of the compound of the invention, or the pharmaceutical composition of the invention can be adjusted by the man skilled in the art of the type and severity of the proteinopathy of the CNS, and to the patient, in particular its age, weight, sex, and general physical condition.

The invention also relates to a pharmaceutical combination of naloxone, as defined above, and tenoxicam, as an additional active ingredient. It deals with said combination for use as a medicament and more specifically for use in the treatment of proteinopathy of the CNS and with the use of this combination in the manufacture of a pharmaceutical composition intended for the treatment of a proteinopathy of the CNS. It is also directed to a method for treating a proteinopathy of the CNS, comprising administering to a patient in need thereof an effective amount of this combination.

The term tenoxicam includes tenoxicam base, or its pharmaceutically acceptable salts and/or solvates, such as detailed for naloxone.

The effective amount of this combination or the relative ratios of both active ingredients may vary upon the subject condition. As detailed earlier, the amount of each compound of the combination or of pharmaceutical composition containing such combination to be administered has to be determined by standard procedure well known by those of ordinary skills in the art. Physiological data of the patient (e.g. age, size, and weight) and the routes of administration have to be taken into account to determine the appropriate dosage, so as a therapeutically effective amount of such combination will be administered to the patient.

The pharmaceutical combination of naloxone and tenoxicam is more specifically for a simultaneous, separate or sequential administration, preferably for simultaneous administration, of said active ingredients.

According to an embodiment of the invention, (i) naloxone and (ii) tenoxicam are administered simultaneously or sequentially, in the form of separate pharmaceutical compositions, one comprising naloxone in a pharmaceutically acceptable support, the other comprising the tenoxicam in a pharmaceutically acceptable support. In another embodiment, naloxone and tenoxicam are combined and administered in the same pharmaceutical composition. In the context of the present invention, the terms “pharmaceutical combination” and “combined administration” refers to one or the other of these aspects.

In more detail, “combined administration” means, for the purpose of the present invention, fixed and, in particular, free combinations, i.e. either naloxone and tenoxicam are present together in one dosage unit, or naloxone and tenoxicam, which are present in separate dosage units, are administered successively, either immediately or at a relatively large time interval; a relatively large time interval means a time span up to a maximum of 24 hours. A “dosage unit” means, in particular, a medicinal dosage form in which the release of the active ingredient(s) is achieved with as few problems as possible, such that the two active-ingredient components (naloxone on the one hand and tenoxicam on the other hand) are released, or made available effectively for the body, in such a way that an optimal active ingredient profile, and thus action profile, is achieved.

The separate dosage units are preferably made available together in one pack and either mixed prior to administration or sequentially administered.

For example, the two dosage units may be packed together in blister packs that are designed with regard to the relative arrangement of the two dosage units with respect to one another, the inscription and/or coloring in a manner known per se so that the times for taking the individual components (dosage regimen) of the two dosage units are evident to a patient. This free combination is of benefit by individually allotting an effective amount of both compounds to the patient. Another possibility is the provision of single preparations of both compounds, i.e. being independent medicaments. The single preparations are converted to contain the required amounts of ingredient for the inventive combination. Corresponding instructions are given at the package insert concerning the combined administration of the respective medicament.

The invention will also be described in further detail in the following examples, which are not intended to limit the scope of this invention, as defined by the attached claims.

EXAMPLES

EXAMPLE 1 - In vivo C. elegans model and evaluation of the activity of Naloxone in the treatment of proteinopathy of the CNS. C. elegans is increasingly used as a screening model to identify novel therapeutic targets or compounds including antimicrobial agents. Expression of PrP in mecanosensitive neurons of the nematode has been chosen because their dysfunction leads to a specific phenotype that can be quantified (Chalfie et al., 1985). As compared to their counterparts expressing a similar level of wild-type human PrP, E200K PrP expressing animals showed PrP aggregates and cell loss in GFP -tagged targeted neurons and formed protease resistant PrP. This model provided a unique tool to assess, in a non-a priori manner, the effect of therapeutic compounds by monitoring the number of GFP-expressing mecanosensitive neurons in human PrP-expressing transgenic worms.

This approach was first validated using a molecule of direct clinical interest (i.e. doxycycline that is currently under evaluation in a long-term preventive trial in a familial form of prion disease, i.e. kindred carrying the D178N-M129 haplotype). Then, a screening of a library of nearly 350 drugs that are known to cross the blood brain barrier and have been FDA-approved was carried out to foster, after further validation steps, clinical application of most promising compounds in prion like diseases, in particular Creutzfeldt-Jakob disease.

Materials and methods

C. elegans Strains, Cultures and synchronization of worms

Animals were generally maintained in Petri dishes on solid nematode growth medium (NGM) seeded with OP50 strain of Escherichia coli as previously described (Brenner, 1974). Synchronized animals were prepared by standard bleach method (Stiernagle, 2006). For liquid culture media, after hatching, larval stage LI animals were incubated at 20°C in liquid S- medium enriched with heat-killed preparation of E. coli OP50 strain as a food source as previously described (Couillault and Ewbank, 2002; Lewis and Fleming, 1995). N2, mec-7 {el 343) strains were obtained from the Caenorhabditis Genetics Center {University of Minnesota, St. Paul, MN) or were generated by transgenesis technique for the purposes of this study.

Plasmids constructs

It was generated various transgenes expression plasmid under the mec-7p constructs {gfp reporter protein, human PRNP wild-type and with the c200E>K mutation,) by using the Gateway system technologies {Thermo Fischer Scientific) as described in Katzen, 2007. It was generated an entry clone vector pDESTby a substitution of the gfp gene (S65C variant) with an entry canonical recombination cassette Att-R (Hartley et al., 2000) at the EcoRl/BamhHA restriction site, upstream the mec-7p promoter in a L2528 plasmid ( Addgene , Cambridge, MA, USA) to constitute the gfp marker plasmid (pNB13 ; mec-7p::gfp). In parallel, it was generated the pENTR clone vectors of the two PRNP transgenes of interest (762 bp; NG 009087.1; wild- type and E200K variant) with a 3’UTR let-858 sequence upstream of the stop codon flanked at their extremities with the Att-L recombination sequences ( PRNP sequences were synthetized by ATUM) to generate the PrPwt (pNB2; mec-7p: :PRNPwt) and RGRE2OOK (pNB8; mec- 7p::PPNPE2ooK ) constructs. The elaborated vectors were transferred in competent bacteria (One Shot TOP 10, Thermo Fischer Scientific) in LB media overnight at 37 °C under agitation at 200 rpm. The total genomic DNA from plasmids was extracted from fresh transformed bacteria using a plasmid DNA Maxi Prep kit according to the recommendations of the manufacturer (Nucleobond XtraMaxi EF, Macherey-Nagel).

Generation of transgenic lines

Transgenics lines, a control GFP-expressing line (named control GFP) and two double transgenic lines coexpressing the full length PRNP (wild-type or c200E>K variant; named PrPwt and RGRE2OOK respectively) and GFP by microinjection following standard transformation techniques (Mello and Fire, 1995) were generated. For microinjection, to generate the control^GFP line (NB13; nblsl3[mec-7p::gfp]) we use the pNB13 plasmid (40 ng/pL) and for the two PrP lines PrPwt (NB2; nbls2 [mec-7p: :PPNPwt;mec-7p: :gfpj) and RGRE2OOK line (NB8; nbls8[mec-7p: :PRNPE200K;mec-7p: :gfp]) it was used a plasmid-mix composed of pNB13 + pNB2 (for PrPw_t)or pNB8 for (RGRE2OOK) at a final concentration of 40 ng/mΐ and 60 ng/pl respectively. Injected animals were isolated to select the FI progeny transformants by the presence of GFP signal in the mechanosensitive system under a large depth fluorescent stereomicroscope ( Leica MZ16). To obtain genetic stable transgenic lines, GFP-expressing larva state L4 animals were isolated and exposed to gamma irradiation exposures (42 Gy; CellRad Faxitron, Edimax) to induce integration of extrachromosomal arrays. Lines showing stable and full transmission of the gfp transgene expression were cloned and backcrossed three times within the N2 wild-type background.

PCR amplification

For mapped specific sequence, single worm PCR were performed as previously described (Williams et ak, 1992). Worms were incubated in a lysis buffer containing 0.1 M Tris-HCl pH 8.5, 0.1 MNaCl, 50 mM EDTA pH 8.0, 1% SDS and frozen at -80 °C. Preparations were thaw at room temperature and proteinase K (RNA grade, Life Technologies) was added at a final concentration of 100 ng/mL and were incubated at 60 °C for one hour and at 95 °C for 5 min. To detect the presence of PRNP transgenes in the transgenic lines, a PCR reaction was performed on 5 pL of DNA using the PCR kit GoTaq Flexi DNA polymerase 829B ( Promega ).

RNA extraction

Pellets of synchronized young adult animals were obtained by centrifugation (1000 rpm; 1 min) and incubated in TRIzol reagent ( Thermo Fisher Scientific). Total RNA was isolated using a Nucleospin RNA isolation kit (Machery-Nagel according to the manufacturer’s protocol. Integrity of RNA samples were assessed using agarose electrophoresis and total RNA concentration was measured with an UV spectrophotometer (Nanodrop 8000; Thermo Scientific). qRT-PCR

Complementary DNAs were synthesized from 200 ng of RNA using a Vilo cDNA Synthesis Kit ( Invitrogen ). For the mRNA quantitative measurements, the primer sets for PRNP trangenes were designed to specifically amplify the 15-138 and 420-640 regions of PRNP. The amount of PRNP cDNAs was normalized against an isoform of peroxisomal membrane protein gene (pmp-3) using a set of primers (Zhang et al., 2012). qRT-PCRs were performed using a LC480 Sybr Green I Master kit {Roche) and reaction mixtures containing 1:3 diluted cDNA, 10 pM each forward and reverse primer and Sybr Green buffer. Reactions were performed using a LightCyler 480 instrument {Roche) and the data were generated with the software provided by the manufacturer using the 2-DDCt method (Doris et al., 1997).

RNA i feeding

Synchronized larval stage LI animals were cultured in NGM plates, seeded with the HT115 (DE3) E. coli strain transformed with the RRNR^RhiAl vector producing, under a T7 IPTG inducible promoter, the dsRNAi (/7Cv7^jRNAl) against RRNR transgene. The empty vector L4440 {Addgene, Cambridge, MA, USA) was used as a control. The production of dsRNAi by the bacteria was induced by addition of 1 mM of isopropyl b-D-l-thiogalactopyranoside (IPTG) previously added to the plate and the worms were chronically exposed to dsRNAi during 3 days at 25 °C according previous described methods (Kamath et al., 2001). The knockdown PRNP transgene effect of dsRNAi was quantified using qRT-PCR technique. Immunostaining

C. elegans strains were synchronized and young adult animals were prepared using a variation of the freeze-crack method (Albertson, 1984). Worms were washed by centrifugation in M9 and placed on poly-L-Lysine-coated slides {superfrost) previously incubated with a drop of poly -L-ly sine hydrobromide ( Sigma-Aldrich ) for 15 min at 60 °C. After cutting the head of the animals, 10x10 mm coverslips were placed gently on the top of the drop and slides were placed on dry ice for 30 min. Coverslips were removed and the nematodes were fixed in 4% paraformaldehyde diluted in methanol for 15 min. The slides were incubated in a series of alcoholic solutions of decreasing concentrations (90, 70, 50, 30 and 10%) then incubated in a PBS solution with 0,01% triton X-100. Preparations were incubated in a blocking solution containing PBS 0.1 % Triton-X100 and 5% skimmed milk for 40 min. Slides were then washed with PBS 0.01% Triton-XIOO. After a pre-treatment using a solution of 3 M guanidine thiocyanate {Sigma-Aldrich) for 5 minutes atRT, samples were incubated with 50 pL of primary antibodies diluted in the blocking solution overnight at 4 °C. The monoclonal anti -prion antibody Sha31 (1:200, from Bertin Bioreagent, that recognizes the human protein sequence within amino acids 145-152) was used. After washing, worms were incubated in a solution containing a secondary anti-mouse antibody {AlexaFluor, Red-548, Life Technologies) for 2 hours at RT. Preparations were stained with Dapi {Sigma Aldrich) to check the effective permeabilization of the cuticle by the treatment. Slides were mounted with 8 pL of anti-fade gold {Life Technologies).

Microscopy images and analysis

Images sections of PLM neurons from slide-mounted young adult animals were captured with an inverse confocal microscope {Leica TCS SP8) using a x63 oil objective. Stacks of 20 images of 0.228 pm step were acquired per GFP tagged PLM neuron. For PrP-clusters quantification, positive neurons presenting PrP-immunospositive intracellular inclusions were identified and scored. Numbers and volumes of inclusions were assessed using Image J software. For each stack images sections, individual inclusions were analysed with the plugin 3D object counter using parameters of size filter to 2-95256 voxels and threshold set to 100.

Neuronal loss assays

Quantification of GFP tagged PLM mechanosensitive neurons were performed in young adult stage hermaphrodites raised at 20 °C, fixed in PBS with 4 % PFA and then mounted on slides for observation. In a first step of drug screening analysis {n = 320 compounds), treated animals were analyzed with an automated system ( Arrayscan XTI - Thermo Fisher Scientific) after having dropped worms in 96-well microplates. Duplicates of twenty -five worms per condition were analyzed. In a second step, the potential neuroprotective effect of pre-selected compounds («=17, 50 animals per condition and per experiment, three independent experiments.), was assessed by manual cell counting under an epifluorescence microscope (Apotome.2 imaging system from Zeiss) using a x63 magnification lens.

Mechanosensitive functional touch test

Touch response assays were performed on young adult synchronised hermaphrodites raised at 20 °C (Chalfie and Sulston, 1981; Chalfie et al., 1985). Animals were rinsed and transferred into a clean NGM plate without food. Touch tests involved scoring for the reflex locomotor response to a light touch at the tail by using a fine hair. Each animal was tested one time and score as responsive or unresponsive. Reflex response was calculated as the percentage of positive responders among the tested population (X animals per condition and per experiment, Y independent experiment). The wild-type N2 strain as positive control and a defective strain {el 343) as a negative control were used.

Slowing basal response test

After synchronization, L4 worms cultured on NGM plates were rinsed in M9 buffer and purified after a short centrifugation (1000 rpm) and were transferred to assay plate. The baseline locomotion level is determined with plate deprived of bacteria and the basal slowing response was determined in presence of food. Basal slowing can also be quantified as: (basal slowing = [movement rate of the animals in the presence of bacteria/movement rate in absence of bacteria] x 100) (Kuwahara et al., 2006). We performed movies during 30 sec (7 fps, AZ100M microscope from Nikon) on a total of 30 worms per condition for each experiment. Locomotion ling velocity was quantified by tracking the centroid of animals of video using the Imaris software (Oxford Instruments). Assays were performed with three independent experiments, n = 30 animals per experimental condition and per experiment.

Swim to crawl transition test

To evaluate dopaminergic behaviours induced by Syn we used a method described by Vidal- Gadea et al. (2011). Behavioural test of young adult animals was preceded by an incubation of 2 h in M9 medium without food source at 20 °C. To motivate the movement of the worms, assay plates containing bacteria were prepared by spreading a drop of OP50 E. coli in the center of the plates followed by incubation at 37 °C overnight. A drop of 5 pL of about 10 worms was placed on the assay plate and the assays began 5 min after the drop was absorbed by the agar, i.e., at a time where the worms were able to escape and start crawling (recordings were done for 5 min on a dry zone). We performed movies during 1 min (7 fps, AZIOOM microscope from Nikon) on a total of 30 worms per condition for each experiment. Crawling velocity was analysed by tracking the centroid of animals by video using the Imaris software (Oxford Instruments). Assays were performed with three independent experiments, n = 30 animals per experimental condition and per experiment.

Motility assay

Young adults were scored on their motility ability in liquid media at 20 °C. Numbers of swimming animals were assessed by direct counting under a stereomicroscope (. LeicaMZ165 ) and the percentage of mobile animal was calculated.

Lifespan

Worms were synchronized, hatched overnight in M9 at 20 °C, transferred in solid media and grown at 20 °C until they reached the L4 developmental stage. They were picked individually and transferred into new NGM plates (10 animals per plate, three plates per line). The lifespan of the animals was daily measured by counting the total of living worms per plate that were transferred in fresh NGM plates every day.

Protein extraction

Nematodes were synchronized, collected using a 30 pm filter (MACS SmartStrainers) and rinsed. They were suspended in extraction buffer containing HEPES-KOH pH 7.4, 25 mM, MgC12 5 mM, EDTA pH 7.4, 1 mM, EGTA 1 mM, NaCl 150 mM, TritonX-100 1.25 %, SDS 0.75 % and with a cocktail of protease inhibitors ( Roche Molecular Biochemicals) and centrifuged at 5000 g during 5 min. The pellets were frozen, 500 mg of beads were added and the samples were homogenized with high frequency mechanical agitation (ribolyser MB biomedicals) with five consecutive runs of 60 s.

The homogenates were sonicated using a sonicator (Misonix Sonicator-3000) with a microtip probe during 10 min at middle intensity (175 W). After centrifugation of the homogenates (2000 g during 3 min), supernatants were recovered, directly frozen in the liquid nitrogen and store at -80 °C. Western blotting, proteinase K treatment and PNGase F incubation

Protein extracts (90 pg per lane) were subjected to a sodium dodecyl sulfate-polyacrylamide gel electrophoresis using 4-12% Bis-Tris gels {Life Technologies). Proteins were electroblotted in transfer buffer (25 mM Tris-base, 200 mM Glycine and 20% methanol) into PVDF membranes {Life Technologies ), blocked during 1 h with 5% skimmed milk in TBS (20 mM Tris-Base, 140 mM NaCl) with 0.1% Twenn-20 and probed for PrP using a mouse monoclonal antiprion antibody (3F4, 1:1000, Covance) overnight at 4°C. Immunostaining was revealed using goat secondary antibodies {Life Technologies) and enhanced chemiluminescence kit {BioLabs).

For some experiments before western blotting analysis, worm homogenates were digested with proteinase K (RNA grade, Life Technologies) diluted in digestion buffer (30 mM EDTA, 30 mM Tris-HCl, 0.5% Tween-20 and 0.5% Triton X-100) for 30 min at 37 °C. For deglycosylation assays, the PK digested homogenates were incubated for 2 h at 37°C with PNGase F enzyme at 1 pg/mL during 1 hour {New England Biolabs).

Quantification of PrP signal

Optical densitometry (OD) of western blotting PrP immunosignals were quantified with a GS- 800 calibrated densitometer and Quantity One software {Bio-Rad Laboratories, France). For each experimental condition, PrP signal prior and after proteinase K (PK) digestion (4 pg/mL during 30 min at 37°C) was analyzed. The ratio between PrP signal after PK and PrP signal before PK for each condition. In this way, the rate of PrP^res after treatment with a tested compound was obtained. Similarly, the rate of PrP^res untreated was obtained. The efficiency of the treatment was evaluated with proportion of the reduction of the PrP^res defined with the calculation: (OD of PrP^res after treatment with tested molecule / OD of the average rate of PrP^res untreated) *100.

Drug testing

A library of ADA-approved compounds {n = 320) described to have a pharmacological biodistribution in the central nervous system was purchased from Prestwick. Lyophilized molecules were solubilized in DMSO 1%, diluted in a ddH20- DMSO 1% to a final concentration of 1 pM, 10 pM and 100 pM, were aliquoted and stocked at -80 °C.

Pharmacological test in liquid media After bleaching, synchronized LI larvas stage were grown in 900 pL of culture liquid media (1 worm/pL) in 24 well plate template without any antibiotics and chronically incubated in presence of 9 pL of the drugs of interests at various concentrations (0 mM, 1 mM, 10 mM and 100 mM final) during 72 h at 25°C until they reach the young adult stage. After incubation with the compounds, worms were washed several times in M9 buffer and analyzed.

Statistical analysis

Quantitative data are expressed as mean ± SEM (error bars) and were independently repeated at least three times. Statistical comparisons of the data between groups were analyzed for significance by one-way analysis of variance (ANOVA). Comparisons were made using Tukey s or Dunnetf s post-hoc test and Student’s t test whenever required. Differences were considered as statistically significant at p < 0.05. Statistical analyses were conducted using Prism 6 ( GraphPad Software).

RESULTS

Generation of PRNP transgenic C. elegans lines

The C. elegans wild-type referenced line N2 was used to generate new lines expressing human PrP. Transgenes were comprised of the promoter sequence of mec-7 , a B-tubulin of C. elegans , fused to wild-type PRNP or to PRNP with the E200K mutation and co-injected with a reporter GFP transgene. 10 and 22 stable lines expressing PRNPmmz. and PRNPm transgenes respectively were obtained. As expected, mec-7 promoter ( mec-7p ) specifically drove GFP expression into the six neurons of the mecanosensitive neuronal system including one pair of neurons in the posterior part of the animal (PLMs), one pair of neurons in the anterior part (ALMs) and two individual neurons (AVM and PVM) as previously described (Chalfie and Sulston, 1981; Tavernarakis and Driscoll, 1997). These observations validated the accurate targeting of the mechanosensitive system by using mec-7p in our various transgenes.

The presence of PRNP transgenes in the C. elegans lines was assessed by PCR amplification technique. In all human PrP expressing lines, migration on agarose gel of the PCR products showed a unique band corresponding to a specific amplicon of 750 bp consistent with the expected size of each PRNP transgene. PCR products were sequenced to validate the entire PRNP transgene for the two genotypes {PRNPm and PRNPE2OOK), notably the presence of a methionine at codon 129 in both lines and of a lysine at codon 200 in the E200K line. To select lines expressing similar level of PrP transgenes, a quantitative analysis of the PRNP mRNA with qRT-PCR using two different sets of primers was performed. All transgenic PRNP lines were studied. A couple of lines (designated as PrPwt and RGRE2OOK) expressing similar amount of mRNA^{,r/ /v< /}’ and RNA^{/ i /}' ^/’^{/i /}’ transcripts as well as similar amounts of mRNAg^? transcripts were selected to allow comparative analysis.

Staining and quantification of intraneuronal PrP inclusions in transgenic nematodes

PrP immunostaining on fixed and permeabilized worms with an anti-PrP monoclonal antibodies commonly used in neuropathological studies of human CJD ( Sha-31 ) were performed. Using confocal microscopy, PrP was detectable in GFP-tagged mechanosensitive neurons only, in both transgenic lines, with a membrane reinforcement of the fluorescent staining, suggesting that the human PrP is correctly expressed at the plasma membrane of the targeted neurons. In addition, in RGRE2OOK line, intraneuronal cytoplasmic clustering of PrP signal was more frequently observed as compared with PrPwt line suggesting the presence of PrP inclusions usually associated to PrP aggregation and accumulation in mammalian prion diseases. These PrP clusters were observed in both cell body and axon of mechanosensitive neurons. p_rpres detection i_n transgenic nematodes

To study the biochemical properties of the different human PrP variants expressed in RGRE2OOK and PrPwt lines, a western-blot study of the prion protein was performed before and after a treatment using proteinase K treatment. In both lines, a tri-bands pattern ranging approximatively from 27kD to 31kD was observed. To assess whether E200K PrP expressed in the nematode shared some of the biochemical properties of PrP^Sc, worm homogenates from both lines were incubated with increasing concentrations of proteinase K before Western blot analysis. A higher PrP resistance to PK digestion in RGRE2OOK animals was observed as compared with PrPwt suggesting that human RGRE2OOK expressed in mecanosensitive neuronal system of nematodes have acquired some of the biochemical and structural properties of PrP^Sc as detected in the brain of patients with E200K CJD (Gabizon et al., 1994; Gabizon et al., 1996; Hainfellner et al., 1999).

Morphological modifications in the PLMs neurons of transgenic nematodes

To further understand how RGRE2OOK expression alters mecanosensitive reflex circuit, the morphology of PLMs neurons in RGRE2OOK line was investigated a severe and significant loss of PLMs neurons in RGRE2OOK line was observed as compared to PrPwt control line. Invalidation of PRNP expression fully restored the number of PLMs neurons confirming the neurotoxic effect of RGRE2OOK expression towards mecanosensitive neurons. To estimate the presence of PrP inclusions in the mechanosensitive neuronal system, it was quantified in more than 150 animals from each PrP line, the number of PLMs showing condensed PrP immuno-signal spotted with the PrP specific Sha-31 antibody. The proportion of PLMs with aggregates increased by 120% in the RGRE2OOK line as compared with the PrPwt line.

It was next investigated the number and the volume of PrP aggregates observed in the cellular body of PLMs neurons using confocal microscopy at high magnification. First, a slight but significant increase of the number of aggregates per neuron in RGRE2OOK line was observed. Second, the volume of PrP-immunopositive neuronal inclusions in different subgroups was categorized. The volume distribution between RGRE2OOK and PrPwt lines was significantly different with a 100% increase in the number of small inclusions ranging from 5 to 20 .10³ pm³ in RGRE2OOK animals.

Phenotypical characterization of transgenic nematodes

To study the functional impact of the deleterious effect of RGRE2OOK expression on mecanosensitive neurons, specific phenotypical tests exploring the mechanosensitive neuronal system were used (Chalfie 1995). The motility in liquid media and the touch reflex response (i.e. touch test assay) were scored, a significant alteration of mobility and touch response in RGRE2OOK line was observed as compared with PrPwt line. It was confirmed that these alterations were due to the expression of RGRE2OOK by invalidating PRNP transgene expression using a RNAi feeding approach.

Decreasing PRNPE2OOK transgene expression by 90% as shown by qRT-PCR in RNAi feed animals fully restored the scores RGRE2OOK animals in neurofunctional assays. These observations suggested that the presence of the RGRE2OOK variant induce a functional defect of the targeted neuronal system.

Screening of a library of FDA-approved compounds that cross the blood-brain-barrier

It was taken advantage of the C. elegans prion model associated with a PrPE2ooK-induced neurotoxicity that allows a largescale analysis using an automated imaging system to screen the efficacy of 320 pharmaceutical compounds from an FDA-approved library described to cross the blood-brain-barrier. The first step was to check in the PrPwt line that the studied compounds have no neuronal toxicity by themselves. It was found five compounds showing a neurotoxic effect. These compounds were thus excluded in further investigations. In the RGRE2OOK line (// = 24 animals per each condition), among the 315 remaining compounds, naloxone compound showed a significant protective effect against RGRE2OOK toxicity on PLM GFP-tagged neurons (Fig. n°l).

Treatment with naloxone was neuroprotective and restored neuronal functionality

The second step focused on candidate molecules (n = 17) previously isolated by the screening assay. They were tested by using a larger number of animals ( n = 50 animals per each condition) and using a different counting method with an epifluorescence microscope.

It was manually assessed the number of posterior GFP-expressing PLMs neurons (Fig. 2). It was fully confirmed the neuroprotective effect of naloxone with effective concentrations ranging from 1 mM to 100 pM. These results obtained in two series of experiments using two different methods of neuronal counting indicated that the neuroprotective effect of naloxone is consistent.

To confirm that the protected neurons are functional, it was further studied the effect of treatment on motionless in liquid media (Fig. 3a) and touch test response (Fig. 3b) behavioral phenotypes. In RGRE2OOK line, naloxone restored significantly, at least in part, motility and reflex response associated with the mecanosensitive system (Fig.3).

Furthermore, PrPwt and RGRE2OOK animals were incubated in presence of a 1, 10 and 100 pM concentration of Naloxone hydrochloride during 3 days. Quantification of the PLMs neurons. n = 50 worms per condition and per experiment (Fig. 2). The results show that Naloxone hydrochloride restores survival and function of mechanosensitive neurons in RGRE2OOK line.

Naloxone induced modifications of intraneuronal PrP aggregates and reduced PrP^res accumulation

It was next studied the effect of the selected compounds on the formation of PrP aggregates observed in PLMs neurons in RGRE2OOK line. Using immunodetection of human PrP and confocal cell imaging, we quantified the volume of PrP aggregates detected in the cell body of PLMs neurons (Fig. 4). Naloxone induced a significant decrease of the volume of intraneuronal PrP aggregates. Then, the effect of naloxone on the accumulation of PrP^res was assessed in RGRE2OOK line using a western blotting approach (Fig. 5). It was observed a decrease in PrP^res signal in animals treated with naloxone as illustrated in figure n°5 with a semi-quantification of PrP^res western blot signal using densitometry.

Association of Naloxone and Tenoxicam protects against the mechanosensitive defect and neuronal death induced by RGRE2OOK expression Transgenic animals expressing the GFP fluorescent marker in the mechanosensitive neuronal system in absence (Control^GFP; PrP ) or in presence of human prion protein (PrPwt and PrP_E200K) were incubated with Tenoxicam and Naloxone alone or in association at 0.25 and 0.5 mM, chronically during 3 days. When associated at such concentration, which is ineffective in monotherapy, a significant effect was observed that restored the motility in liquid media, the mechanosensitive neuronal functionality and the number of PrP expressing mechanosensitive neurons (Fig.6).

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Claims

1. Naloxone compound for use in the treatment of a proteinopathy of the central nervous system (CNS) in a subject, wherein the proteinopathy of the CNS is an animal or human prion disease.

2. The compound for use according to claim 1, wherein the animal or human prion disease is selected from chronic wasting disease, bovine spongiform encephalopathy, scrapie, Creutzfeldt-Jakob disease (CJD), familial fatal insomnia, sporadic fatal insomnia, and Ger stmann- S trails si er- S cheinker syndrome .

3. The compound for use according to claim 1 or 2, wherein the proteinopathy is a human prion disease.

4. The compound for use according to any one of claims 1 to 3, wherein the human prion disease is selected in the group consisting of Creutzfeldt-Jakob disease (CJD), including sporadic CJD, inherited CJD and infectious CJD, familial fatal insomnia, sporadic fatal insomnia, and Gerstmann-Straiissler-Scheinker syndrome.

5. The compound for use according to any one of claims 1 to 4, wherein the prion disease is Creutzfeldt-Jakob's disease.

6. The compound for use according to any one of claims 1 to 5, wherein naloxone is naloxone hydrochloride.

7. The compound for use according to any one of claims 1 to 6, wherein the treatment prevents or delays the onset and/or the progression of said proteinopathy of the CNS.

8. The compound for use according to any one of claims 1 to 7, wherein the treatment has a neuroprotective effect or restore neuronal functionality.

9. A pharmaceutical composition for use in the treatment of an animal or human prion disease in a subject in need thereof, comprising a therapeutically effective amount of naloxone compound and a pharmaceutically acceptable support.

10. The pharmaceutical composition for use according to claim 9, wherein the composition is in a form suitable for topical, oral, enteral, parenteral, subcutaneous or intraocular intravenous, intraventricular, percutaneous, intrathecal, epidural or intranasal administration.

11. The pharmaceutical composition for use according to claim 9 or 10, wherein the composition is in a form suitable for injection.

12. A pharmaceutical combination of naloxone and tenoxicam for use as a medicament.

13. The combination of claim 12, for use in the treatment of proteinopathy of the CNS.

14. The combination for use according to claim 12 or 13, for a simultaneous, separate or sequential administration, preferably for simultaneous administration, of naloxone and tenoxicam.

15. The combination for use according to claim 13 or 14, wherein the proteinopathy of the CNS is selected from the group consisting of diseases associated with deposits of amyloid b peptides, diseases associated with tau inclusions, animal and human prion diseases, alpha-synucleinopathies, diseases associated with polyglutamine (polyQ) expansion in multiple proteins, and motor neurone diseases.

16. The combination for use according to any one of claims 13 to 15, wherein the proteinopathy of the CNS is selected from the group consisting of cerebral amyloid angiopathy, Alzheimer’s disease, primary age-related tauopathy, Down’s syndrome, progressive supranuclear palsy, corticobasal degeneration, amyotrophic lateral sclerosis/parkinsonism-dementia complex, Parkinson's disease, Lewy body dementia, multiple system atrophy, pure autonomic dysfunction with synuclein deposition, Lewy body subtype Alzheimer's disease, essential tremor with Lewy bodies, familial parkinsonism with or without dementia, drug-induced parkinsonism with a-synuclein deposition, metabolic storage disorders such as Gaucher's disease, Huntington's disease, dentatorubral-pallidoluysian atrophy (DRPLA), several types of spinocerebellar ataxias, and amyotrophic lateral sclerosis.

17. The combination for use according to any one of claims 13 to 15, wherein the proteinopathy of the CNS is an animal or human prion disease, more particularly selected from chronic wasting disease, bovine spongiform encephalopathy, scrapie, Creutzfeldt-Jakob disease (CJD), familial fatal insomnia, sporadic fatal insomnia, and

Ger stmann- S trails si er- S cheinker syndrome .

18. The combination for use according to any one of claims 13 to 15, wherein the proteinopathy is a human prion disease, in particular selected from the group consisting of Creutzfeldt-Jakob disease (CJD), including sporadic CJD, inherited CJD and infectious CJD, familial fatal insomnia, sporadic fatal insomnia, and Gerstmann- Straiissler-Scheinker syndrome.

19. The combination for use according to any one of claims 13 to 15, wherein the prion disease is Creutzfeldt-Jakob's disease.