Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K38/00—Medicinal preparations containing peptides
  • A61K38/16—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • A61K38/17—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/19—Carboxylic acids, e.g. valproic acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/19—Carboxylic acids, e.g. valproic acid
  • A61K31/192—Carboxylic acids, e.g. valproic acid having aromatic groups, e.g. sulindac, 2-aryl-propionic acids, ethacrynic acid 
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/19—Carboxylic acids, e.g. valproic acid
  • A61K31/20—Carboxylic acids, e.g. valproic acid having a carboxyl group bound to a chain of seven or more carbon atoms, e.g. stearic, palmitic, arachidic acids
  • A61K31/203—Retinoic acids ; Salts thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/38—Heterocyclic compounds having sulfur as a ring hetero atom
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/38—Heterocyclic compounds having sulfur as a ring hetero atom
  • A61K31/381—Heterocyclic compounds having sulfur as a ring hetero atom having five-membered rings
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K38/00—Medicinal preparations containing peptides
  • A61K38/16—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • A61K38/17—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
  • A61K38/177—Receptors; Cell surface antigens; Cell surface determinants
  • A61K38/1783—Nuclear receptors, e.g. retinoic acid receptor [RAR], RXR, nuclear orphan receptors
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K48/00—Medicinal preparations containing genetic material which is inserted into cells of the living body to treat genetic diseases; Gene therapy

Definitions

• the present invention relates to a factor relating to neurite growth
• neurite development such as neurite outgrowth and/or neurite regeneration, for example in cases of nervous injuries such as spinal cord injuries
• Nerve growth factor is known to stimulate certain events such as neurite outgrowth
• NGF nerve growth factor
• NGF is a relatively large molecule with a correspondingly high molecular weight
• NGF is susceptible to protease mediated degradation Due to these and other considerations, NGF is difficult to administer NGF is also relatively expensive to prepare
• the present invention is based on the surprising finding that it is possible to cause neurite development, such as neurite outgrowth and/or neurite regeneration, by using RAR ⁇ 2 and/or an agonist thereof
• the present invention relates to the use of RAR ⁇ 2 and/or an agonist thereof in the preparation of a medicament to cause neurite development
• RAR ⁇ 2 and/or an agonist can be termed a pharmaceutically active agent
• Neuntes are well known structures which develop from various neuronal cell types They appear as microscopic branch or comb-like structures or morphological projections from the surface of the cell from which they emanate Examples of neurite outgrowth are shown in the accompanying figures, and in publications such as those referenced in (Maden 1998-rev ⁇ ew article), and are well known in the art
• the RAR ⁇ 2 coding sequence (i e the RAR ⁇ 2 gene) is used as described hereinbelow
• the RAR ⁇ 2 gene may be prepared by use of recombinant DNA techniques and/or by synthetic techniques For example it may be prepared using the PCR amplified gene fragment prepared as in the Examples section of this document using the primers etc detailed therein, or it may be prepared according to any other suitable method known in the art
• the present invention relates to the use of RAR ⁇ 2 and/or an agonist thereof in the preparation of a medicament to cause neurite development, wherein said agonist is retinoic acid (RA) and/or CD2019
• CD2019 is a polycyclic heterocarbyl molecule which is a RAR ⁇ 2 agonist having the structure as discussed herein and as shown in (Elmazar et al , (1996) Teratology vol 53 pp158-167)
• the present invention relates to the use of RAR ⁇ 2 and/or an agonist thereof in the preparation of a medicament for the treatment of a neurological disorder
• the present invention relates to the use of RAR ⁇ 2 and/or an agonist thereof in the preparation of a medicament for the treatment of a neurological disorder, wherein said neurological disorder comprises neurological injury
• the present invention relates to a method of treating a neurological disorder comprising administering a pharmacologically active amount of an RAR ⁇ 2 receptor, and/or an agonist thereof
• the present invention relates to a method of treating a neurological disorder comprising administering a pharmacologically active amount of an RAR ⁇ 2 receptor, and/or an agonist thereof, wherein said agonist is RA and/or CD2019
• the present invention relates to a method of treating a neurological disorder comprising administering a pharmacologically active amount of an RAR ⁇ 2 receptor, and/or an agonist thereof, wherein said RAR ⁇ 2 receptor is administered by an entity comprising a RAR ⁇ 2 expression system
• the present invention relates to a method of causing neurite development in a subject, said method comprising providing a nucleic acid construct capable of directing the expression of at least part of a RAR ⁇ 2 receptor, introducing said construct into one or more cells of said subject, and optionally administering a RAR ⁇ 2 agonist, such as RA and/or CD2019, to said subject
• the invention relates to an assay method for determining whether an agent is capable of modulating RAR ⁇ 2 signalling, said method comprising providing neural cells, contacting said cells with said agent, and assessing the activity of the RAR ⁇ 2 receptor, such as through the monitoring of neurite outgrowth
• Neural ceils for use in the assay method of the invention may be any suitable neural cell line, whether stably maintained in culture, or primary cells derived from an animal directly Preferably said cells will be embryonic mouse dorsal root ganglion (DRG) cells prepared as described hereinbelow
• the invention relates to a process comprising the steps of (i) performing the assay for modulation of RAR ⁇ 2 signalling described above, (n) identifying one or more agents that are capable of modulating said RAR ⁇ 2 signalling, and (in) preparing a quantity of those one or more identified agents
• the invention relates to a process comprising the steps of (i) performing the assay for modulation of RAR ⁇ 2 signalling described above, (n) identifying one or more agents that are capable of modulating said RAR ⁇ 2 signalling, (in) preparing a quantity of those one or more identified agents, and (iv) preparing a pharmaceutical composition comprising those one or more identified agents
• the invention relates to a method of affecting the in vivo activity of RAR ⁇ 2 with an agent, wherein the agent is capable of modulating RAR ⁇ 2 signalling, for example capable of modulating RAR ⁇ 2 signalling in an in vitro assay method as described above
• the invention relates to the use of an agent in the preparation of a pharmaceutical composition for the treatment of a neurological disorder or injury, wherein the agent is capable of modulating RAR ⁇ 2 signalling, for example capable of modulating RAR ⁇ 2 signalling in an in vitro assay method as described above
• the invention relates to a method of treating a subject with an agent, wherein the agent is capable of modulating RAR ⁇ 2 signalling, for example capable of modulating RAR ⁇ 2 signalling in an in vitro assay method as described above
• the invention relates to a pharmaceutical composition
• a pharmaceutical composition comprising RAR ⁇ 2 and/or an agonist thereof in admixture with a pharmaceutically acceptable carrier, diluent or excipient, wherein the pharmaceutical composition is for use to cause neurite development
• the administration of a nucleic acid construct capable of directing the expression of RAR ⁇ 2 will be accompanied by the administration of a RAR ⁇ 2 agonist such as RA, or preferably CD2019 (or a mimetic thereof)
• said agonist will be to some degree selective for the RAR ⁇ 2 receptor Preferably said agonist will not significantly affect the RAR ⁇ receptor Preferably said agonist will not significantly affect the RAR ⁇ receptor More preferably said agonist will not significantly affect the RAR ⁇ receptor or the RAR ⁇ receptor Even more preferably, said agonist will exhibit a high degree of selectivity for the RAR ⁇ 2 receptor
• the administration of a nucleic acid construct capable of directing the expression of RAR ⁇ 2 will be accomplished using a vector, preferably a viral vector, more preferably a retroviral vector
• the administration of a nucleic acid construct capable of directing the expression of RAR ⁇ 2 will be accomplished using a retroviral vector capable of infecting non-dividing mammalian cells such as neural cells
• the present invention is advantageous because RAR ⁇ 2 and/or an agonist thereof can cause modulation of neural cell development
• Retinoids are a family of molecules derived from vitamin A and include the biologically active metabolite, retinoic acid (RA)
• RA retinoic acid
• the cellular effects of RA are mediated through the action of two classes of receptors, the retinoic acid receptors (RARs) which are activated both by all- trans- A (tRA) and 9-c ⁇ s-KA (9-cw-RA), and the retinoid X receptors (RXRs), which are activated only by 9-c/s-RA (Kastner et al , 1994, Kleiwer et al , 1994)
• RARs retinoic acid receptors
• RXRs retinoid X receptors
• the receptors are of three major subtypes, ⁇ .
• the RARs mediate gene expression by forming heterodimers with the RXRs. whilst the RXRs can mediate gene expression as homodimers or by forming heterodimers with a variety of orphan receptors (Mangelsdorf & Evans, 1995)
• RA can stimulate both neurite number and length (review, Maden, 1998), as, indeed, can the neurotrophins (Campenot, 1977, Lindsay, 1988, Tuttle and Mathew, 1995)
• the neurotrophins are a family of growth factors that are required for the survival of a variety of neurons of primary sensory neurons in the developing peripheral nervous system (Snider, 1994)
• NURR1 One of the earliest genes induced by NGF in PC 12 cells is the orphan receptor NGFI-B (NURR1) (Millbrandt. 1989) This suggests that
• retinoic acid receptors alpha, beta, and gamma
• Retmoic acid was the first morphogen described in vertebrates
• the RARA and RARB genes are more homologous to those of the 2 closely related thyroid hormone receptors THRA and THRB, located on chromosomes 17 and 3, respectively, than to any other members of the nuclear receptor family
• the RARB gene formerly symbolized HAP, maps to 3p24 by somatic cell hybridization and in situ hybridization Benbrook et al (1988) showed a predominant distribution in epithelial tissues and therefore used the designation RAR(eps ⁇ lon) By in situ hybridization, Mattel et al (1988) assigned the RARB gene to 3p24 Using
• HBV integration site present in a particular human hepatocellular carcmoma (HCC) with the correspondmg unoccupied site in the nontumorous tissue of the same liver
• HCC human hepatocellular carcmoma
• RARB-RXRB, RARJB-RXRG, and RXRB-RXRG mice showed no defects in locomotion, even though both RARA and RARG are also expressed in the st ⁇ atum
• the morphology, development, and function of skeletal muscle, peripheral nerves, and spmal cord were normal in all single and double null mutants, as were balance reflexes
• Kreczel et al 1998 that RARB, RXRB, and RXRG are involved specifically in the control of locomotor behaviors, and that heterodimers of RARB with either RXRB or RXRG are the functional receptor units, such that RXRB and RXRG are functionally redundant Kreczel et al (1998)stud ⁇ ed the expression of D l and D2 dopamine receptors (D1R and D2R), the most abundant dopamine receptors in the st ⁇ atum, in these
• the reduction was mostly in the medioventral regions of the st ⁇ atum, including the shell and core of the nucleus accumbens, and the mediodorsal part of the caudate putamen
• the reduction was not due to loss of D2R-express ⁇ ng neurons, no increase in apoptosis was noted
• the histology of the st ⁇ atum was normal
• the agonist of the present invention may be any suitable RAR ⁇ 2 agonist
• said agonist of RAR ⁇ 2 is capable of activating RAR ⁇ 2 in a transactivation assay
• the agonist may be an organic compound or other chemical
• the agonist can be an ammo acid sequence or a chemical derivative thereof, or a combination thereof
• the agent may even be a nucleotide sequence - which may be a sense sequence or an anti-sense sequence
• the agent may even be an antibody
• the agonist will be an organic compound
• the organic compound will comprise two or more hydrocarbyl groups
• the term "hydrocarbyl group” means a group comprising at least C and H and may optionally comprise one or more other suitable substituents Examples of such substituents may include halo-, alkoxy-, nitro-, an alkyl group, a cyclic group etc
• substituents may include halo-, alkoxy-, nitro-, an alkyl group, a cyclic group etc
• a combination of substituents may form a cyclic group
• the hydrocarbyl group comprises more than one C then those carbons need not necessarily be linked to each other
• at least two of the carbons may be linked via a suitable element or group
• the hydrocarbyl group may contain hetero atoms Suitable hetero atoms will be apparent to those skilled in the art and include, for instance sulphur, nitrogen and oxygen
• the agent comprises at least one cyclic group
• the cyclic group may be a
• RA retinoic acid
• tRA all-trans retinoic acid
• 9-c ⁇ s- RA 9-c ⁇ s- RA
• CD2019 is a RAR ⁇ 2 agonist having the structure as discussed herein and as shown in (Elmazar et a/ , (1996) Teratology vol 53 pp158-167) This and other agonists are also discussed in (Beard and Chandraratna p 194, Johnson et a/ , 1996) The structure of CD2019 is presented as Formula I in the attached figures
• the present invention also encompasses mimetics or bioisosteres of the formulae of Formula I and/or Formula II
• the agonist useful according to the present invention is selective for RAR ⁇ 2
• Examples of agonists according to the present invention may be identified and/or verified by using an assay to determine RAR ⁇ 2 agonism
• the present invention also encompasses (i) detemining if a candidate agent is capable of acting as a RAR ⁇ 2 agonist, (n) if said candidate agent is capable of acting as a RAR ⁇ 2 agonist then delivering said agent to a subject and in such an amount to cause neurite development ASSAY
• any one or more of appropriate targets - such as an ammo acid sequence and/or nucleotide sequence - may be used for identifying an agent capable of modulating RAR ⁇ 2 in any of a variety of drug screening techniques
• the target employed in such a test may be free in solution, affixed to a solid support, borne on a cell surface, or located intracellularly The abolition of target activity or the formation of binding complexes between the target and the agent being tested may be measured
• the assay of the present invention may be a screen, whereby a number of agents are tested
• the assay method of the present invention is a high through put screen
• This invention also contemplates the use of competitive drug screening assays in which neutralising antibodies capable of binding a target specifically compete with a test compound for binding to a target
• HTS high throughput screening
• the present invention relates to a method of identifying agents that selectively modulate RAR ⁇ 2
• the assay of the present invention utilises cells that display RAR ⁇ 2 on their surface These cells may be isolated from a subject possessing such cells However, preferably, the cells are prepared by transfecting cells so that upon transfect those cells display on their surface RAR ⁇ 2
• WO-A-9849271 Another example of an assay that may be used is described in WO-A-9849271 , which concerns an immortalised human terato-carcinoma CNS neuronal cell line, which is siad to have a high level of neuronal differentiation and is useful in detecting compounds which bind to RAR ⁇ 2
• reporter gene may encode an enzyme which catalyses a reaction which alters light absorption properties
• reporter molecules include but are not limited to (galactosidase, invertase, green fluorescent protein, luciferase, chloramphenicol, acetyltransferase, (glucuronidase, exo-glucanase and glucoamylase Alternatively, radiolabelled or fluorescent tag-labelled nucleotides can be incorporated into nascent transcripts which are then identified when bound to o gonucleotide probes
• reporter molecules or labels include those radionuclides, enzymes fluorescent, chemiluminescent, or chromogenic agents as well as substrates, cofactors, inhibitors, magnetic particles and the like Patents teaching the use of such labels include US- A-3817837, US-A-3850752 US-A-3939350, US-A-3996345, US-A-4277437, US-A- 4275149 and US-A-4366241
• Polynucleotides for use in the present invention - such as for use as targets or for expressing targets or for use as the pharmaceutically active agent - may be introduced into host cells
• host cell in relation to the present invention includes any cell that could comprise the polynucleotide sequence of the present invention
• polynucleotides may be introduced into prokaryotic cells or eukaryotic cells, for example yeast, insect or mammalian cells
• Polynucleotides of the invention may introduced into suitable host cells using a variety of techniques known in the art, such as transfection transformation and electroporation Where polynucleotides of the invention are to be administered to animals, several techniques are known in the art, for example infection with recombinant viral vectors such as retroviruses, herpes simplex viruses and adenoviruses, direct injection of nucleic acids and biohstic transformation
• a further embodiment of the present invention provides host cells transformed or transfected with a polynucleotide that is or expresses the target of the present invention
• a polynucleotide that is or expresses the target of the present invention
• said polynucleotide is carried in a vector for the replication and expression of polynucleotides that are to be the target or are to express the target
• the cells will be chosen to be compatible with the said vector and may for example be prokaryotic (for example bacterial), fungal, yeast or plant cells
• the gram negative bacterium E coll is widely used as a host for heterologous gene expression
• large amounts of heterologous protein tend to accumulate inside the cell
• Subsequent purification of the desired protein from the bulk of E.coli intracellular proteins can sometimes be difficult.
• bacteria from the genus Bacillus are very suitable as heterologous hosts because of their capability to secrete proteins into the culture medium.
• Other bacteria suitable as hosts are those from the genera Streptomyces and Pseudomonas.
• eukaryotic hosts such as yeasts or other fungi may be preferred.
• yeast cells are preferred over fungal cells because they are easier to manipulate.
• some proteins are either poorly secreted from the yeast cell, or in some cases are not processed properly (e.g. hyperglycosylation in yeast). In these instances, a different fungal host organism should be selected.
• suitable expression hosts within the scope of the present invention are fungi such as Aspergillus species (such as those described in EP-A-0184438 and EP- A-0284603) and Trichoderma species; bacteria such as Bacillus species (such as those described in EP-A-0134048 and EP-A-0253455), Streptomyces species and Pseudomonas species, and yeasts such as Kluyveromyces species (such as those described in EP-A-0096430 and EP-A-0301670) and Saccharomyces species
• typical expression hosts may be selected from Aspergillus niger Aspergillus niger var. tubigenis, Aspergillus niger var.
• Polypeptides that are extensively modified may require correct processing to complete their function
• mammalian cell expression systems such as HEK-293, CHO, HeLA
• the polypeptides are expressed either intracellularly, on the cell membranes, or secreted in the culture media if preceded by an appropriate leader sequence.
• suitable host cells - such as yeast, fungal, plant and mammalian host cells - may provide for post-translational modifications (e.g. mynstoylation, glycosylation, truncation, lipidation and tyrosine, serine or threonine phosphorylation) as may be needed to confer optimal biological activity on recombinant expression products of the present invention
• post-translational modifications e.g. mynstoylation, glycosylation, truncation, lipidation and tyrosine, serine or threonine phosphorylation
• organism in relation to the present invention includes any organism that could comprise the sequence according to the present invention and/or products obtained therefrom Examples of organisms may include a fungus, yeast or a plant
• transgenic organism in relation to the present invention includes any organism that comprises the target according to the present invention and/or products obtained
• the host organism can be a prokaryotic or a eukaryotic organism
• suitable prokaryotic hosts include E coli and Bacillus subtilis Teachings on the transformation of prokaryotic hosts is well documented in the art, for example see Sambrook et al (Molecular Cloning A Laboratory Manual, 2nd edition, 1989, Cold Spring Harbor Laboratory Press) and Ausubel et al , Current Protocols in Molecular Biology (1995), John Wiley & Sons, Inc.
• nucleotide sequence may need to be suitably modified before transformation - such as by removal of mtrons
• the transgenic organism can be a yeast
• yeast have also been widely used as a vehicle for heterologous gene expression
• the species Saccharomyces cerevisiae has a long history of industrial use, including its use for heterologous gene expression
• Expression of heterologous genes in Saccharomyces cerevisiae has been reviewed by Goodey et al (1987 Yeast Biotechnology, D R Berry et al, eds, pp 401-429, Allen and Unwin, London) and by King et al (1989, Molecular and Cell Biology of Yeasts, E F Walton and G T Yarronton, eds, pp 107-133, Blackie, Glasgow)
• Saccharomyces cerevisiae is well suited for heterologous gene expression
• yeast vectors include mtegrative vectors, which require recombination with the host genome for their maintenance, and autonomously replicating plasmid vectors
• expression constructs are prepared by inserting the nucleotide sequence of the present invention into a construct designed for expression in yeast
• a promoter active in yeast fused to the nucleotide sequence of the present invention usually a promoter of yeast origin, such as the GAL1 promoter, is used
• a signal sequence of yeast origin such as the sequence encoding the SUC2 signal peptide, is used
• a terminator active in yeast ends the expression system
• transgenic Saccharomyces can be prepared by following the teachings of Hinnen et al (1978, Proceedings of the National Academy of Sciences of the USA 75, 1929), Beggs, J D (1978, Nature, London, 275, 104), and Ito, H et al (1983, J Bacteriology 153, 163- 168)
• the transformed yeast cells are selected using various selective markers Among the markers used for transformation are a number of auxotrophic markers such as LEU2, HIS4 and TRP1 , and dominant antibiotic resistance markers such as aminoglycoside antibiotic markers, eg G418
• Another host organism is a plant
• the basic principle in the construction of genetically modified plants is to insert genetic information in the plant genome so as to obtain a stable maintenance of the inserted genetic material
• Several techniques exist for inserting the genetic information the two mam principles being direct introduction of the genetic information and introduction of the genetic information by use of a vector system
• a review of the general techniques may be found in articles by Potrykus (Annu Rev Plant Physiol Plant Mol Biol [1991] 42 205-225) and Chnstou (Agro-Food- Industry Hi-Tech March/April 1994 17-27) Further teachings on plant transformation may be found in EP-A-0449375
• hosts suitable for the nucleotide sequence of the present invention include higher eukaryotic cells, such as insect cells or vertebrate cells, particularly mammalian cells, including human ceils, or nucleated cells from other muiticellular organisms
• eukaryotic cells such as insect cells or vertebrate cells, particularly mammalian cells, including human ceils, or nucleated cells from other muiticellular organisms
• mammalian host cell lines such as epithelial or fibroblastic cell lines such as Chinese hamster ovary (CHO) cells, NIH 3T3 cells, HeLa cells or 293T cells
• the nucleotide sequence of the present invention may be stably incorporated into host cells or may be transiently expressed using methods known in the art
• stably transfected mammalian cells may be prepared by transfecting cells with an expression vector having a selectable marker gene, and growing the transfected cells under conditions selective for cells expressing the marker gene
• mammalian cells are transfected with a reporter gene to monitor transfection efficiency
• the cells should be transfected with a sufficient amount of the nucleotide sequence of the present invention
• the precise amounts of the nucleotide sequence of the present invention may be empirically determined and optimised for a particular cell and assay
• the present invention also provides a method of transforming a host cell with a nucleotide sequence that is to be the target or is to express the target
• Host cells transformed with the nucleotide sequence may be cultured under conditions suitable for the expression of the encoded protein
• the protein produced by a recombinant ceil may be displayed on the surface of the cell
• expression vectors containing coding sequences can be designed with signal sequences which direct secretion of the coding sequences through a particular prokaryotic or eukaryotic cell membrane
• Other recombinant constructions may join the coding sequence to nucleotide sequence encoding a polypeptide domain which will facilitate purification of soluble proteins (Kroll DJ et al (1993) DNA Cell Biol 12 441-53)
• the RAR ⁇ 2 receptor as discussed herein includes mimetics, homologues, fragments and part or all of the entire gene product Preferably the RAR ⁇ 2 receptor as discussed herein refers to substantially the entire gene product
• neurological disorders may refer to any injury, whether mechanically (for example by trauma) or chemically induced (for example by neurotox ⁇ n(s), or by an regime of treatment having an immunosuppressant effect, whether by design, or as a side-effect), any neural pathology such as caused by viral infection or otherwise, any degenerative disorder, or other nerve tissue related disorder
• neurological disorders include conditions such as Parkinson's disease, Alzheimer's disease, senility, motor neurone disease, schizophrenia as well as other neural and/or neurodegenerative disorders
• Other neural related disorders may include glaucoma or other cause of damage to the optic nerve, Bell's palsy or other forms of localised paralysis, neurally based impotence such as caused by nerve trauma following radical prostatectomy, or other complaints
• Other disorders in which the invention may be useful include neuropathological effects of diabetes, AIDS neuropathy, leprosy etc
• the term neurological disorder refers to any disorder of a nervous system, whether the peripheral nervous system or the central nervous system (CNS), whether the sympathetic nervous system, or the parasympathetic nervous system, or whether affecting a subset or superset of different nerve types NUCLEOTIDE OF INTEREST (NOI)
• the NOI sequence may encode a peptide which peptide may be the pharmaceutically active agent - such as an RA receptor, preferably RAR ⁇ 2, or an agonist thereof
• Such coding NOI sequences may be typically operatively linked to a suitable promoter capable of driving expression of the peptide, such as in one or more specific cell types
• the delivery system may contain additional genetic elements for the efficient or regulated expression of the gene or genes, including promoters/enhancers, translation initiation signals, internal ⁇ bosome entry sites (IRES), splicing and polyadenylation signals
• the NOI or NOIs may be under the expression control of an expression regulatory element, usually a promoter or a promoter and enhancer
• the enhancer and/or promoter may be preferentially active in neural cells such that the NOI is preferentially expressed in the particular cells of interest, such as in nerve cells Thus any significant biological effect or deleterious effect of the NOI on the individual being treated may be reduced or eliminated
• the enhancer element or other elements conferring regulated expression may be present in multiple copies Likewise, or in addition, the enhancer and/or promoter may be preferentially active in one or more specific cell types - such as neural cells for example post-mitotically terminally differentiated non-replicating cells such as neurons
• promoter is used in the normal sense of the art, e g an RNA polymerase binding site in the Jacob-Monod theory of gene expression
• promoter includes a DNA sequence which binds to other protein components of the transcription initiation complex and thus facilitates the initiation of transcription directed by its associated promoter
• the NOI (e g that encoding RAR ⁇ 2 or part thereof) used in the method of the present invention is inserted into a vector which is operably linked to a control sequence that is capable of providing for the expression of the coding sequence by the host cell, i e the vector is an expression vector
• target vector refers to a vector whose ability to infect/transfect/transduce a cell or to be expressed in a host and/or target cell is restricted to certain cell types within the host organism, usually cells having a common or similar phenotype
• the delivery system for use in the present invention may be any suitable delivery system for delivering said NOI and providing said NOI is expressed in vivo to produce said associated peptide (e g RAR ⁇ 2), which in turn provides the beneficial therapeutic effect
• the delivery system may be a viral delivery system
• Viral delivery systems include but are not limited to adenovirus vector, an adeno-associated viral (AAV) vector, a herpes viral vector, retroviral vector, lentiviral vector, baculoviral vector
• the delivery system may be a non-viral delivery system - such as by way of example DNA transfection methods of, for example, plasmids, chromosomes or artificial chromosomes
• transfection includes a process using a non-viral vector to deliver a gene to a target mammalian cell
• Typical transfection methods include electroporation, DNA bioiistics, pid-mediated transfection, compacted DNA-mediated transfection, liposomes, immunohposomes, lipofectin, cationic agent-mediated, cationic facial amphiphiies (CFAs) (Nature Biotechnology 1996 14, 556), and combinations thereof
• Other examples of vectors include ex vivo delivery systems - which include but are not
• the delivery system is a vector
• the delivery system is a viral delivery system - sometimes referred to as a viral vector
• a vector is a tool that allows or faciliates the transfer of an entity from one environment to another
• some vectors used in recombinant DNA techniques allow entities, such as a segment of DNA (such as a heterologous DNA segment, such as a heterologous cDNA segment), to be transferred into a target cell
• the vector may then serve to maintain the heterologous DNA within the cell or may act as a unit of DNA replication
• examples of vectors used in recombinant DNA techniques include plasmids, chromosomes, artificial chromosomes or viruses
• vector includes expression vectors and/or transformation vectors
• expression vector means a construct capable of in vivo or in vitro/ex vivo expression
• transformation vector means a construct capable of being transferred from one species to another
• the NOI may be introduced into suitable host cells using a viral delivery system (a viral vector)
• a viral delivery system a viral vector
• viral techniques are known in the art, such as for example infection with recombinant viral vectors such as retroviruses, herpes simplex viruses and adenoviruses
• Suitable recombinant viral vectors include but are not limited to adenovirus vectors, adeno-associated viral (AAV) vectors, herpes-virus vectors, a retroviral vector, lentiviral vectors, baculoviral vectors, pox viral vectors or parvovirus vectors (see Kestler et al 1999 Human Gene Ther 10(10): 1619-32)
• gene delivery is typically mediated by viral infection of a target cell.
• retroviruses include but are not limited to: munne leukemia virus (MLV), human immunodeficiency virus (HIV), equine infectious anaemia virus (EIAV), mouse mammary tumour virus (MMTV).
• MMV munne leukemia virus
• HCV human immunodeficiency virus
• EIAV equine infectious anaemia virus
• MMTV mouse mammary tumour virus
• Preferred vectors for use in accordance with the present invention are recombinant viral vectors, in particular recombinant retroviral vectors (RRV) such as lentiviral vectors.
• RRV retroviral vectors
• RRV recombinant retroviral vector
• RRV refers to a vector with sufficient retroviral genetic information to allow packaging of an RNA genome, in the presence of packaging components, into a viral particle capable of infecting a target cell. Infection of the target cell includes reverse transcription and integration into the target cell genome.
• the RRV carries non-viral coding sequences which are to be delivered by the vector to the target cell.
• An RRV is incapable of independent replication to produce infectious retroviral particles within the final target cell.
• the RRV lacks a functional gag-pol and/or env gene and/or other genes essential for replication.
• the pharmaceutically active agent (e g the RAR ⁇ 2) may be administered using non- viral techniques
• the pharmaceutically active agent may be delivered using peptide delivery Peptide delivery uses domains or sequences from proteins capable of translocation through the plasma and/or nuclear membrane
• Polypeptides of interest such as RAR ⁇ 2 may be directly introduced to the cell by micromjection, or delivery using vesicles such as liposomes which are capable of fusing with the cell membrane
• Viral fusogenic peptides may also be used to promote membrane fusion and delivery to the cytoplasm of the cell
• the RAR ⁇ 2 or fragment(s) thereof may be delivered into cells as protein fusions or conjugates with a protein capable of crossing the plasma membrane and/or the nuclear membrane
• the RAR ⁇ 2 or fragment(s) thereof is fused or conjugated to a domain or sequence from such a protein responsible for the translocational activity
• Preferred translocation domains and sequences include domains and sequences from the HIV-1-trans-act ⁇ vat ⁇ ng protein (Tat), Drosophila Antennapedia homeodomain protein and the herpes simplex- 1 virus VP22 protein
• Exogenously added HIV-1-trans-act ⁇ vat ⁇ ng protein can translocate through the plasma membrane and to reach the nucleus to transactivate the viral genome Translocational activity has been identified in ammo acids 37-72 (Fawell et al , 1994, Proc Natl Acad Set U S A 91 , 664-668), 37-62 (Anderson et al , 1993 Biochem Biophys Res Commun 194, 876-884) and 49-58 (having the basic sequence RKKRRQRRR) of HIV-Tat Vives et al (1997), J Biol Chem 272, 16010-7 identified a sequence consisting of ammo acids 48-60 (CGRKKRRQRRRPPQC), which appears to be important for translocation, nuclear localisation and trans-activation of cellular genes The third helix of the Drosophila Antennapedia homeodomain protein has aiso been shown to possess similar properties (reviewed in Prochiantz, A , 1999, Ann N Y Aca
• the present invention also provides a pharmaceutical composition
• a pharmaceutical composition comprising administering a therapeutically effective amount of the agent of the present invention (such as RAR ⁇ 2 and/or an agonist thereof as discussed herein) and a pharmaceutically acceptable carrier, diluent or excipients (including combinations thereof)
• the pharmaceutical composition may comprise two components - wherein a first component comprises RAR ⁇ 2 and a second component which comprises the agonist thereof
• the first and second component may be delivered sequentially, simultaneously or together, and even by different administration routes
• compositions may be for human or animal usage in human and veterinary medicine and will typically comprise any one or more of a pharmaceutically acceptable diluent, carrier, or excipient Acceptable carriers or diluents for therapeutic use are well known in the pharmaceutical art, and are described, for example, in Remington's Pharmaceutical Sciences, Mack Publishing Co (A R Gennaro edit 1985)
• the choice of pharmaceutical carrier, excipient or diluent can be selected with regard to the intended route of administration and standard pharmaceutical practice
• the pharmaceutical compositions may comprise as - or in addition to - the carrier, excipient or diluent any suitable b ⁇ nder(s), lubr ⁇ cant(s), suspending agent(s), coating agent(s), solubiiising agent(s)
• Preservatives, stabilizers, dyes and even flavoring agents may be provided in the pharmaceutical composition
• preservatives include sodium benzoate, sorbic acid and esters of p-hydroxybenzoic acid
• Antioxidants and suspending agents may be also used
• the pharmaceutical composition of the present invention may be formulated to be delivered using a mini-pump or by a mucosal route, for example, as a nasal spray or aerosol for inhalation or ingestable solution, or parenterally in which the composition is formulated by an injectabie form, for delivery, by, for example, an intravenous, intramuscular or subcutaneous route
• the formulation may be designed to be delivered by both routes
• the agent is to be delivered mucosally through the gastrointestinal mucosa, it should be able to remain stable during transit though the gastrointestinal tract, for example, it should be resistant to proteolytic degradation, stable at acid pH and resistant to the detergent effects of bile
• the pharmaceutical compositions can be administered by inhalation, in the form of a suppository or pessary, topically in the form of a lotion, solution, cream, ointment or dusting powder, by use of a skin patch, orally in the form of tablets containing excipients such as starch or lactose, or in capsules or ovules either alone or in admixture with excipients, or in the form of elixirs, solutions or suspensions containing flavouring or colouring agents, or they can be injected parenterally, for example intravenously, intramuscularly or subcutaneously
• the compositions may be best used in the form of a sterile aqueous solution which may contain other substances, for example enough salts or monosacchandes to make the solution isotonic with blood
• buccal or subl gual administration the compositions may be administered in the form of tablets or lozenges which can be formulated in a conventional manner PHARMACEUTICAL
• the agent of the present invention may be administered with one or more other pharmaceutically active substances
• the present invention covers the simultaneous, or sequential treatments with an agent according to the present invention and one or more steroids, analgesics, antivirals or other pharmaceutically active substance(s)
• Figure 1 (which is Figure 1 referred to in Example 1) shows a photograph
• FIG 2 (which is Figure 2 referred to in Example 1 ) shows barcharts and a photograph Figure 3, (which is Figure 1 referred to in Example 2) shows a photograph Figure 4, (which is Figure 2 referred to in Example 2) shows a photograph Figure 5, (which is Figure 3 referred to in Example 2) shows a photograph Figure 6, (which is Figure 4 referred to in Example 2) shows a photograph Figure 7, (which is Figure 5 referred to in Example 2) shows a photograph Figure 8, (which is Figure 6 referred to in Example 2) shows a barchart Figure 9, (which is Figure 1 referred to in Example 3) shows a photograph Figure 10, (which is Figure 2 referred to in Example 3) shows a photograph Figure 11 , (which is Figure 3 referred to in Example 3) shows a photograph Figure 12, (which is Figure 4 referred to in Example 3) shows a photograph Figure 13, (which is Figure 5 referred to in Example 3) shows a photograph Figure 14, (which is Figure 6 referred to in Example 3) shows a photograph Figure 15, (which is Figure 7 referred to in Example 3) shows bar
• Nerve growth factor acts via retinoic acid synthesis to stimulate neurite outgrowth.
• Nerve growth factor stimulates neurite outgrowth from cultured adult dorsal root ganglia (DRG) 1.
• DRG dorsal root ganglia
• RA retinoic acid
• RA retinoic acid receptors
• RXRs retinoid X receptors
• RAR receptors mediate gene expression by forming heterodimers with the RXRs, whereas RXRs can mediate gene expression either as homodimers or by forming heterodimers with orphan receptors such as LXR8
• NGF nuclear receptor NGFIB heterodimerizes with the RXRs ⁇ and that NGFIB is rapidly induced in PC12 cells by the administration of NGF9.
• NGF or RA plus NGF groups (Fig. 2a; 2, 3 and 4). Although it may be that both NGF and RA are at individual saturating concentrations, the lack of synergy may also imply that NGF and RA act through the same pathway in order to cause neurite outgrowth.
• RA inducing the production of NGF5 or NGF inducing the production of RA by stimulating a RA-synthesizing enzyme.
• NGF is upstream of RA. it should induce synthesis of RA after addition to DRG cultures.
• F9 reporter cell line that responds specifically to the presence of RA due to transfection with 1.8 kb of the mouse RAR ⁇ 2 gene promoter containing a retinoic acid response element (RARE) linked to the lacZ gene
• RARE retinoic acid response element
• retinoic acid synthesizing enzymes might be induced by NGF.
• Retinol is converted by a two-step oxidative process to an aldehyde, retinal, which is then oxidized to retinoic acid (for review, see refi 1 1).
• RALDH-2 retinaldehyde dehydrogenase type 2
• Fig. 2e up- regulation of the RAR ⁇ receptor in NGF-stimulated cultures
• NGFIB is one of the earliest genes induced by NGF9 and its product can heterodimerize with the RXRs8, the NGFIB/RXR heterodimer may be responsible for activating the RALDH-2 gene.
• Neurotrophins classically have been considered as potential agents for induction of nerve regeneration 14 and treatment of neurodegenerative diseasesl5, but a major problem for their use is lack of effective modes of delivery to the site of the injury. Because RA is required for the regenerative response and it is downstream of NGF, then the problem of delivery to the lesion could be overcome, as RA is a low- molecular- weight lipophilic compound that can be administered orally. Thus. RA may be of clinical use in neurology.
• Fig. 1 Neurite outgrowth in adult mouse DRG cultured for five (a-d, g, h) or eight days (e. f) in the presence of delipidated serum plus: (a) no addition; (b) NGF, 100 ng per ml; (c) NGF and 100 nM tRA; (d) NGF and 10 M disulphiram; (e) disulphiram and tRA added on day 0; (f) disulphiram; (g) NGF and blocking antibody (h) NGF- blocking antibody and tRA.
• Fig. 2. (a-c) Neurites produced by adult DRG cultured in cellogen.
• retinoic acid receptor- ⁇ 2 induces neurite outgrowth in the adult mouse spinal cord
• Retinoic acid has been shown to be required for neunte outgrowth
• the adult central nervous system cannot regenerate Theretore.
• RAR ⁇ 2 which is activated by retinoic acid (RA) the biologically active metabolite of vitamin A.
• RA retinoic acid
• RA acts at the level of gene transcription because it is a ligand for two classes of nuclear transcription factors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs) 18 ' 19 .
• RARs retinoic acid receptors
• RXRs retinoid X receptors
• RAR ⁇ 2 is the crucial transducer of the RA signal in neurons as it is up-regulated in situations where RA stimulates neurite outgrowth-0. We hypothesised therefore that the absence or below threshold level of this nuclear receptor in the adult spinal cord may contribute to the failure of this tissue to regenerate axonal projections.
• mice embryonic spinal cord will respond to RA by extending neurites as do other areas of the embryonic CNS 1 * ⁇ 17 - 21-23 ⁇ d r at tn i s behaviour involves an up-regulation of RAR ⁇ 2.
• El 3.5 spinal cord was dissected from mouse embryos placed in a cellogen matrix and cultured in 10 % delipidated serum.
• All-trans-RA was added at 3 different concentrations (10 _8 M, 10 "7 M. 10 "6 M) and after 5 days the explants were stained with a neurofilament antibody and examined for the presence of neurites.
• Fig. 1A Even in the absence of RA the embryonic cord extended neurites (Fig. 1A) presumably because of the high endogenous content of RA and its precursor retinol ⁇ S Indeed, when the endogenous synthesis of RA is inhibited with disulphiram then no neurites are extended-24.
• NGF stimulates neurite outgrowth and acts by up-regulating RAR ⁇ 2 24 and neurite outgrowth from embryonic mouse DRG can be stimulated by a RAR ⁇ agonist * ⁇ .
• the primers used were from GAPDH, RAR ⁇ 2 and RAR ⁇ 4, (details upon request).
• PCR was carried out for 25 cycles for embryonic spinal cord and 40 cycles for adult spinal cord.
• Amplification was carried out as follows, denaturation for 30 s at 95 °C, annealing for 30 s at 55 °C and extension for 1 min at 72 °C. One fifth of the resultant product was then run on a gel.
• FIGURES FOR EXAMPLE 2 are identical to FIGURES FOR EXAMPLE 2:
• Fig.l Comparison of the effect of retinoic acid on neurite outgrowth on cultured
• El 3.5 (A, C, E, G) and 10 month old adult spinal cord (B, D, F, H). Pieces of spinal cord were cultured in cellogen in the presence of 10 % delipidated serum and RA for a period of five days. The medium was changed every two days. A, B, no RA; C. D. 1 x 10" 8 M RA: E, F, 1 x 10" 7 M RA; G, H, 1 x 10 "6 M RA.
• FIG.2 Expression of RAR ⁇ 2 in El 3.5 and 10 month old adult spinal cord. Pieces of spinal cord were cultured in the presence of various concentrations of RA for a period of five days after which time RT-PCR analysis of RAR ⁇ 2 was performed. A. El 3.5 (lanes 2-5) and B. 10 month old adult spinal cord (lanes 2-5). Lanes: 1. bluescript/ ⁇ PA
• Fig.3. Transfection of adult spinal cord with pHSVlacZ. Cultured 10 month old adult spinal cord was transfected with 5 x 10"4 ipu/ul pHSVlacZ overnight and analysed for B galactosidase staining 3 days later. A. non-transfected adult spinal cord. B. adult spinal transfected with pHSVlacZ.
• Fig.4 Transfection of adult spinal cord with either pHSVRAR ⁇ 2 or pHSVRAR ⁇ 4.
• Adult spinal cord was cultured in cellogen and transfected either with 5 x 10 -4 ipu ul of pHSVRAR ⁇ 2 or 4 x 10" 4 ipu/ul pHSVRAR ⁇ 4 overnight.
• RT-PCR analysis four days after transfection. of RAR ⁇ 2 (lanes 2-4) and RAR ⁇ 4 (lanes 6-8) expression in adult spinal cord transfected with Lanes 2, 6 no virus . 3, 7 pHSVRAR ⁇ 2, 4, 8, pHSVRAR ⁇ 4.
• the presence of GAPDH was used to indicate equal amounts of cDNA in the samples.
• Fig.5. Effect of either pHSVlacZ, pHSVRAR ⁇ 2 or pHSVRAR ⁇ 4 transfection in cultured adult spinal cord on neurite outgrowth.
• Ten month old spinal cord was cultured in cellogen and transfected with either 5 x 10" 4 ipu/ul, pHSVlacZ, 5 x 10 "4 ipu/ul, pHSVRAR ⁇ 2 or 4 x 10" 4 ipu/ul pHSVRAR ⁇ 4 overnight, and analysed for neurite staining with NF200 4 days after transfection.
• Fig. 6 is a barchart of the average number of neurites per spinal cord explant.
• EXAMPLE 3 NEURITE OUTGROWTH FROM MOUSE GANGLIAL NEURONES
• retinoic acid receptors The role of retinoic acid receptors in neurite outgrowth from different populations of embryonic mouse dorsal root ganglia.
• Dorsal root ganglion (DRG) neurons can be categorised into at least three types based upon their neurotrophin requirement for survival.
• RARs retinoic acid receptors
• RXRs retinoid X receptors
• the neurotrophins are a family of growth factors that are required for the survival of a variety of primary sensory neurons in the developing peripheral nervous system (Snider, 1994).
• the family includes nerve growth factor (NGF) (Levi-Montalcini, 1987) neurotrophin- 3 (NT-3) (Maisonpiene et al., 1990) and brain-derived neurotrophic factor (BDNF) (Barde et al., 1982). They are synthesised in the target fields innervated by peripheral neurons and are thought to be transported by a retrograde mechanism from the target field to support the survival of the developing neurons.
• the neurotrophins act through receptor tyrosine kinases designated Trk.
• NGF specifically activates TrkA; BDNF activates TrkB and NT-3 activates TrkC (reviewed in Snider, 1994).
• DRG dorsal root ganglia
• Neurons that require NGF for their survival mediate nocioceptive (pain) and thermal receptive functions. In the periphery the axons terminate in the superficial layers of the skin and innervate the superficial laminae of the spinal cord (Crowley et al., 1994; Smeyne et al., 1994) .
• Proprioceptive neurons (sense of position of the limbs in space), which are much larger than NGF type neurons, project into the periphery to the primary endings of muscle spindles and extend a collateral branch to the motor pools in the spinal cord are dependent upon NT-3 for their survival (Ernfors et al., 1994; Farinas et al., 1994: Klein et al., 1994).
• BDNF neurons are small to medium sized and may include some classes of the mechanoreceptors (Klein et al., 1993: Jones et al., 1994).
• retinoids are a family of molecules derived from vitamin A and include the biologically active metabolite, retinoic acid (RA).
• RA retinoic acid
• the cellular effects of RA are mediated through the action of two classes of receptors, the retinoic acid receptors (RARs) which are activated both by all-trans-RA (tRA) and 9-cis-RA (9-cis-RA), and the retinoid X receptors (RXRs), which are activated only by 9-cis-RA (Kastner et al., 1994; Kleiwer et al., 1994).
• RARs retinoic acid receptors
• RXRs retinoid X receptors
• the receptors are of three major subtypes, ⁇ , ⁇ and ⁇ , of which there are multiple isoforms due to alternative splicing and differential promoter usage (Leid et al. 1992).
• the RARs mediate gene expression by forming heterodimers with the RXRs. whilst the RXRs can mediate gene expression as homodimers or by forming heterodimers with a variety of orphan receptors (Mangelsdorf & Evans, 1995).
• one of the earliest genes induced by NGF in PC12 cells is the orphan receptor NGFI-B (NURRl) (Millbrandt. 1989). This suggests that the growth factor and retinoid mediated pathway in developing neurons can interact.
• RA has been shown to be involved in the survival and differentiation of neurons (Wuarin and Sidell, 1991; Quinn and De Boni, 1991). Furthermore, many studies on a variety of embryonic neuronal types have shown that RA can stimulate both neurite number and length (reviewed in Maden, 1998) as indeed, can the neurotrophins (Campenot, 1977; Lindsay, 1988; Tuttle and Mathew, 1995). Recently we have shown that RA is critical for neurite regeneration in adult DRG and that it ' s synthesis may be regulated by NGF (Corcoran and Maden, 1999).
• DRG cultures DRG were obtained from E13.5 mice, freed of non-ganglionic tissue and collected in ice-cold calcium magnesium free phosphate buffered saline. To prepare dissociated cell suspensions the ganglia were treated with 0.05 % trypsin for 15 minutes at 15 °C. The reaction was stopped by the addition of 1% serum and single cells obtained by trituration with a 23 G needle. The cells were then spun at 1000 g for ten minutes and resuspended in media. They were plated out at a density of approximately of 25000 cells/cm 2 in wells that had been precoated with lOO ⁇ g/ml poly D lysine for 2 firs. The cultures were fed every 2 days.
• Culture media consisted of DMEM-F12 with glutamine (Gibco). 6 % glucose, ITS (Gibco).
• the growth factors used were either 50ng/ml NGF (7s. Promega) 50ng/ml NT3 (Promega) or 50ng/ml BDNF (Promega).
• Retinoids were used at a concentration of 1 x 10" 7 M. All-tr ⁇ rcs-retinoic acid was obtained from Sigma and the receptor agonists were synthesised by CIRD Galderma: CD366 activates RAR ⁇ , CD2019 activates RAR ⁇ , CD437 activates RAR ⁇ and CD2809 activates all of the RXRs. RT-PCR analysis.
• the primers used were from mouse RARs, RXRs and GAPDH (details upon request).
• GAPDH GAPDH
• Amplification was carried out in the linear range for each RAR and RXR and their levels of expression were compared to GAPDH. For the RXRs 28 cycles were performed, while 25 cycles were used for RAR ⁇ and RAR ⁇ and 22 cycles for RAR ⁇ and GAPDH.
• Amplification was carried out as follows, denaturation for 30 s at 95 °C, annealing for 30 s at 55 °C and extension for 1 min at 72 °C.
• One fifth of the resultant product was then run on a gel and blotted. This was then probed with the appropriate RAR, RXR or GAPDH for normalisation.
• In situ Hybridisation Cells were washed once with PBS and fixed in 4% PFA for 30 mins. They were then washed twice for 5 mins in PBS-0.05% Tween (PBT). Hybridisation was carried out at 55 °C overnight.
• the buffer consisted of 0.1M Tris- Cl, pH9.5, 0.05M MgCb, 0.1M NaCl and 0.1% Tween-20.
• the cells were then washed sequentially for 15 min. at 65°C in 50 % hybridisation buffer, 50% 2x SSC, 100% 2x SSC, and finally in 0.2% SSC. They were e then washed at RT for 5 minutes each in 75% 0.2x SSC, 25% PBT, 50% 0.2x SSC.
• RAR ⁇ 2 isoform
• This isoform was strongly up-regulated by RA in the NGF (Fig. 4 A, lane 6) and NT-3 dependent neurons (Fig. 4 B, lane 6) but not in the BDNF dependent neurons (Fig. 4 C, lane 6) as compared to the non-stimulated cultures (Fig. 4 A, B, C, lane 2).
• RAR ⁇ i was detected in the neuronal cultures and then only in the NGF (Fig. 5 A, lane 1 and 8) and NT-3 dependent neurons (Fig. 5 B, lane 1 and 8). No RAR ⁇ i was detected by RT-PCR in the BDNF dependent neurons.
• RAR ⁇ i or RAR ⁇ 2 may be responsible for the increase of neurite outgrowth observed in the NGF and NT-3 dependent neurons (Fig. 2 B, D). It is more likely to be the RAR ⁇ 2 isoform since this receptor is not upregulated in the BDNF dependent neurons and there is no increase in neurite outgrowth when these are stimulated with RA (Fig. 2 F) whereas the RAR ⁇ i isoform is up-regulated despite a lack of neurite response to RA.
• receptor selective synthetic retinoids which have been developed specifically to activate individual receptors. CD366 activates RAR ⁇ , CD2019 activates RAR ⁇ , CD437 activates RAR ⁇ and CD2809 activates all of the RXRs.
• RAR ⁇ 2 is required for neurite outgrowth. Furthermore, RAR ⁇ can inhibit neurite outgrowth.
• RAR ⁇ 2 is reduced in both the NGF and NT-3 dependent neurons (Fig. 8 B, lanes 2 and 5) compared to non-stimulated cultures (Fig. 8 B, lanes 1 and 4).
• the RAR ⁇ agonist had no effect on the level of RAR ⁇ i (Fig. 8 A, lanes 2 and 5).
• RAR ⁇ i can regulate the expression of RAR ⁇ 2.
• RAR ⁇ agonist caused a decrease in neurite outgrowth of the NGF and NT-3 dependent neurons.
• RAR ⁇ agonists had any effect on -receptor expression.
• the RAR ⁇ agonist upregulated the expression of RAR ⁇ 2 but had no effect on the expression of RAR ⁇ i.
• RAR ⁇ agonist had no effect on the expression of RAR ⁇ i it did down-regulate the level of RAR ⁇ 2 expression, this phenomenon may also be a prelude to neurite outgrowth. This suggests that the RAR ⁇ transcript can be regulated by RAR ⁇ /RXR heterodimers.
• the differential response of these neurons to RA and the receptor agonists may have some significance for embryonic and adult tissues which require retinoids for their development and/or survival.
• retinoids In order to activate different RAR/RXR and RXR/orphan receptor combinations there may be different retinoids present in the tissues.
• Some support for this view is provided by the fact that there are numerous RA generating enzymes which show localised expression during development (McCaffery et al., 1992; Drager & McCaffery, 1995; Godbout et al.. 1996: Neideneither et al., 1997; Ang & Duester, 1997) and each of these enzymes could make different retinoids.
• Several novel retinoids have so far been discovered, for example 5.
• 6- epoxyretinoic acid which is found in the intestine (McCormick et al., 1978), 4-oxo- retinol which is the biologically active metabolite that is responsible for the differentiation of murine embryonic F9 cells (Achkar et al., 1996) and 14- hydroxy-4, 14-retroretinol which is found in B lymphocytes (Buck et al., 1991).
• the embryo may be able to regulate the amount of neurite outgrowth by synthesising different retinoids.
• the amount of neurite outgrowth could be regulated by the amount of retinoic acid.
• the amount of retinoic acid For example in the developing mouse spinal cord there are high concentrations of retinoids in the brachial and lumbar enlargements (McCaffery & Drager. 1994).
• FIG. 1 Expression of the RARs and RXRs by El 3.5 mouse embryo DRG neurons cultured either in the presence of NGF. NT-3 or BDNF. In situ hybridisation of: A-F, NGF neurons; G-L, NT-3 neurons; M-R, BDNF neurons. Expression of : A, G, M, RAR ⁇ ; B, H, N, RAR ⁇ ; C, I, O, RAR ⁇ ; D, J, P. RXR ⁇ ; E, K, , RXR ⁇ ; F, L, R, RXR ⁇ .
• FIG. 1 Effect of RA on neurite outgrowth from DRG neurons.
• DRG neurons were cultured either in the presence of NGF, NT-3 or BDNF for a period of two days at which point 1 x 10" 7 M a l-trans-RA was added. They were then examined for neurite outgrowth after a total of five days with NF200 antibody.
• FIG. 3 Expression of RAR ⁇ isoforms in DRG neurons cultured either in the absence or presence of RA. DRG neurons were cultured in the presence of either NGF, NT-3 or BDNF for a period of two days, 1 X 10" 7 M RA was then added and the presence of the RAR ⁇ isoforms were then assayed by RT-PCR. Controls had no RA added. A, control NGF neurons lanes 1-7; NGF neurons + 1 X 10" 7 M RA lanes 8-14. B, control NT-3 neurons lanes 1-7; NT-3 neurons + 1 X 10 "7 M RA lanes 8-14. C, control BDNF neurons lanes 1-7; BDNF neurons + 1 X 10" 7 M RA lanes 8-14.
• Figure 4. Expression of RAR ⁇ isoforms in DRG neurons cultured either in the absence or presence of RA. DRG neurons were cultured in the presence of either NGF, NT-3 or BDNF for a period of two days, 1 X 10 "7 M RA was then added and the presence of the RAR ⁇ isoforms were then assayed by RT-PCR. Controls had no RA added. A.
• DRG neurons were cultured in the presence of either NGF, NT-3 or BDNF for a period of two days, 1 X 10" 7 M RA was then added and the presence of the RAR ⁇ isoforms were then assayed by RT-PCR. Controls had no RA added.
• B control NT-3 neurons lanes 1-7; NT-3 neurons + 1 X 10 "7 M RA lanes 8-14.
• FIG. 6 Effect of RAR and RXR agonists on neurite outgrowth from DRG neurons.
• DRG neurons were cultured either in the presence of NGF , NT-3 or BDNF for a period of two days at which point either 1 x 10" 7 M of either CD366 (RAR ⁇ agonist), CD2019 (RAR ⁇ agonist), CD437 (RAR ⁇ agonist) or CD2809 (pan-RXR agonist) were added to the cultures. Cultures were then stained for neurite outgrowth at five days with the NF200 antibody.
• A-D NGF type neurons
• E-H NT-3 type neurons
• I-L BDNF type neurons.
• Agonists RAR ⁇ A, E, I; RAR ⁇ B, F, J; RAR ⁇ C, G, K; RXR D, H, L.
• Figure 8. Effect of a RAR ⁇ or RAR ⁇ agonist on the expression of RAR ⁇ i and RAR ⁇ 2 expression in DRG neurons cultured in the presence of NGF or NT-3. DRG neurons were cultured in the presence of serum free medium. After two days 1 x 10" M RAR ⁇ or RAR ⁇ agonist were then added to the cultures for a period of 24 hrs.
• RAR ⁇ 2 and/or an agonist thereof can be used to cause neurite development.
• peripheral nerves When peripheral nerves are damaged some regeneration can occur unlike nerves of the central nervous system which show no regeneration. However regeneration of peripheral nerves is limited particularly when there is traumatic nerve injury where there is a loss of nerve tissue such that a gap is created which the regenerating neurite cannot grow across. This delay in nerve regeneration can lead to muscle atrophy and lead to permanent disability.
• neurotrophins are produced in response to peripheral nerve injury. These are a family of growth factors that are required for the survival of a variety of neurons .
• the family includes nerve growth factor (NGF) neurotrophin- 3 (NT-3) and brain-derived neurotrophic factor (BDNF).
• NGF nerve growth factor
• NT-3 neurotrophin- 3
• BDNF brain-derived neurotrophic factor
• tRA all-trans-retinoic acid
• NGF retinoid X receptors
• RARs retinoic acid receptors
• RXRs retinoid X receptors
• ⁇ , ⁇ and ⁇ three subtypes of each: ⁇ , ⁇ and ⁇ .
• RAR receptors mediate gene expression by forming heterodimers with the RXRs
• RXRs can mediate gene expression either as homodimers or by forming heterodimers with orphan receptors.
• retinoids unlike neurotrophins are small lipophilic molecules which can be easily administered to the site of injury therefore regeneration should occur at a much quicker rate than can be achieved with neurotrophins, this should lead to a reduction in muscle atrophy and consequent paralysis.
• the stimulation of RAR ⁇ 2 is crucial to the regeneration of all neurons we have tested only one type of retinoid need be taken circumventing the need to administer a cocktail of neurotrophins.
• retinoids are relatively easy to synthesise unlike neurotrophins.
• RAR ⁇ 2 agonists can be used to treat PNS injuries including neuropathy associated with leprosy, diabetes and AIDS.
• Gene therapy with RAR ⁇ 2 can be used to treat CNS injuries.
• the present invention therefore comprises a method of treatment of neurodegenerative disease in which expression of the retinoic acid receptor RAR ⁇ 2 is ensured in affected cells or tissues. This may be achieved by treatment with an agonist of the RAR ⁇ 2 receptor or by gene therapy i.e. insertion of the nucleic acid coding for this receptor.
• the invention may also be seen as the use of these agents in medication for the treatment of peripheral nervous injuries and spinal cord regeneration e.g. in cases of paraplegia.
• Mattel, M -G de The, H Mattel, J -F , Marchio, A , Tiollais, P , Dejean, A Assignment of the human hap retinoic acid receptor RAR-beta gene to the p24 band of chromosome 3 Hum Genet 80 189-190, 1988 9 Mattel, M -G , Riviere, M , Krust, A , Ingvarsson, S , Vennstrom, B , Islam, M Q , Levan G , Kautner, P , Zelent, A , Chambon, P , Szpirer, J , Szpirer, C Chromosomal assignment of retmoic acid receptor (RAR) genes in the human, mouse, and rat genomes Genomics 10 1061-1069, 1991
• Vitamin A-deficient quail embryos have half a hindbrain and other neural defects. Current Biol. 6, 417-426 (1996).
• Nerve growth factor acts via retinoic acid synthesis to stimulate neurite outgrowth. Nat. Neuroscience 2, 307-308.
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