Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
  • C07H17/00—Compounds containing heterocyclic radicals directly attached to hetero atoms of saccharide radicals
  • C07H17/04—Heterocyclic radicals containing only oxygen as ring hetero atoms
  • C07H17/08—Hetero rings containing eight or more ring members, e.g. erythromycins
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/04—Antibacterial agents
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
  • C07H17/00—Compounds containing heterocyclic radicals directly attached to hetero atoms of saccharide radicals
  • C07H17/02—Heterocyclic radicals containing only nitrogen as ring hetero atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
  • C07H3/00—Compounds containing only hydrogen atoms and saccharide radicals having only carbon, hydrogen, and oxygen atoms
  • C07H3/06—Oligosaccharides, i.e. having three to five saccharide radicals attached to each other by glycosidic linkages
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
  • C07H5/00—Compounds containing saccharide radicals in which the hetero bonds to oxygen have been replaced by the same number of hetero bonds to halogen, nitrogen, sulfur, selenium, or tellurium
  • C07H5/04—Compounds containing saccharide radicals in which the hetero bonds to oxygen have been replaced by the same number of hetero bonds to halogen, nitrogen, sulfur, selenium, or tellurium to nitrogen
  • C07H5/06—Aminosugars

Definitions

• the present invention relates to glycomimetic compounds as anti-infectious against pathogens that use lectins in the first steps of infection.
• Pseudomonas aeruginosa also called the pyocyanic bacillus, is a gram negative bacterium that lives in humid environment and soil. It is associated with human activities and is present in kitchen, bathroom, hospitals etc. This opportunistic bacterium is responsible of severe nosocomial infections in immunocompromised patients, a population that is increasing with the larger number of transplantations. In France, P. aeruginosa has been responsible of 8% of nosocomial infections during the period from August 2001 to June 2006 (Institut denier making, BHE 30-31 , 2008). It is a common cause of infection of burns, but also eyes and ears, and it is also responsible of the majority of colonisation on medical devices such as catheters.
• P. aeruginosa bacterium is also a major causative agent of lung infections in cystic fibrosis (CF) patients. In most cases, CF patients suffer from chronic pulmonary infection when they reach teenager development. These infections are the major cause of morbidity and mortality. Once chronic infection is established, it is very difficult or even impossible to eradicate it because of the occurrence of many strains that present multi-resistance to antibiotics. The formation of P. aeruginosa biofilms that results in increasing resistance to host immunity and to antibiotics also complicates the therapeutical approach. The rapid emergence of many pathogenic microorganisms presenting resistance towards drug compounds such as antiviral or antibiotics is a major concern for public health. The need for alternative therapeutical strategies is now urgent.
• P. aeruginosa produces a large number of protein receptors that are able to specifically recognize carbohydrates. These receptors, called lectins, play a role in adhesion to host tissue and in biofilm formation.
• the lectins are either produced in soluble form in the bacteria or present at the apex of adhesives organelles.
• LecA (PA-IL) and LecB (PA-IIL) are soluble lectins that are produced in the cytoplasm of P. aeruginosa but have also been detected in large quantity on the outer membrane of the bacterial cells.
• LecA and LecB are both tetrameric protein and recognize galactose and fucose, respectively, in a calcium-dependant way (Gilboa-Garber, Methods Enzymol. 1982, 83, 378-385).. They are considered as virulence factors for the bacteria and are co-expressed with enzymes and other proteins during infection. LecA has been demonstrated to be toxic to airway cells (Bajolet-Laudinat et al. Infect. Immun. 1994, 62, 4481 -4487) and also plays a role in the formation and stabilisation of the bacteria biofilm.
• LecB is also involved in biofilm formation (Tielker et al., Microbiology 2005, 151 , 1313-1323) and inhibits ciliary beating in lung cells in culture (Adam et ai, Am. J. Respir. Crit. Care Med. 1997, 155, 2102-2104).
• the infectious process is initiated by the specific recognition of host epithelia glycoconjugates by bacterial receptors referred to as lectins.
• the carbohydrate specificity of these lectins determines the targeting for hosts and tissues.
• the recognition step is followed by adhesion, a process that triggers many cellular pathways in both the bacteria and host therefore influencing the next step of invasion and colonisation.
• Blocking the adhesion by glycocompounds that act as soluble analogs of glycoconjugates here called “glycomimetics” in opposition with the natural sugars or glycoconjugates) is therefore one possible strategy against infection.
• glycomimetics enter in competition with the natural glycoconjugates present on the human tissues and thus block the bacteria adhesion and the development of colonies. Characterizing the interaction between bacterial lectins and host glycoconjugates has been a necessary step for the design of glycomimetics that can interfere in the process, and therefore limit the bacterial adhesion and/or the formation of biofilms.
• Carbohydrates and derivatives are a promising source of anti-infectious compounds since many infections are initiated by the adhesion of the microorganisms on the host cell surface. Rather than killing the bacteria by antibiotics, a process that induces emergence of resistant strains, the proposed alternative is to interfere with the adhesion process.
• the characterisation of the natural oligosaccharides involved in the bacterial adhesion helps in the design of soluble analogues (ie the glycomimetics) that are able to compete with the cell surface glycoconjugates.
• the advantages of antibacterial glycomimetics are their local use and their absence of toxicity. Furthermore, the risk of resistance is weak since it does not affect directly the bacteria metabolism. Finally, such compounds can be used in conjunction with other treatments, such as antibiotics.
• glycomimetic compounds are thus a route of interest for inhibiting the adhesion of pathogens to human tissues and some of them have already been developed for bacterial infection affecting gastro-intestinal track, urinary track or ears.
• glycomimetics designed against FirmH, a lectin present on pili of uropathogenic E. coli were demonstrated not only to block adhesion of bacteria on bladder epithelia but also to inhibit biofilm production (Wellens et al., PLoS One. 2008, 3, 2040).
• WO 2005/089733, WO 2007/021721 and WO 2007/143052 documents disclose oligosaccharides targeted to some bacterial infections.
• glycomimetics when developing glycomimetics, one has to remember that a strong affinity is required in order to get efficient competition with cell surface glycoconjugates, and it is not always easy to develop such glycomimetics. Lectin-carbohydrate interactions are often characterized by low affinity (millimolar range) and this has been a major barrier in the development of biologically active glycomimetic compounds. It has been demonstrated that multivalency is an efficient strategy for significantly increasing the interaction between the compounds and the target. Several approaches have been used, ranging from low valency for the glycoclusters to high valency for the glycodendrimers or glycopolymers. Glycodendrimers directed against FirmH demonstrated to be efficient as anti-adhesive compounds against uropathogenic E.
• the affinity of the glycomimetics for the lectins does not depend only on the number of sugars displayed by the calixarene glycoconjugates, i.e. the valency, but also on the length and flexibility of the linkers of the calixarene glycoconjugates, said linkers connecting the sugar moiety to the calixarene moiety.
• the calixarene moiety that provides valency varying from 1 to 4, it is therefore necessary to develop new classes of molecules, based on new linkers bringing different properties to the final glycomimetics compounds.
• One aim of the present invention is to provide novel glycomimetic compounds able to selectively block the lectin A and/or the lectin B from Pseudomonas aeruginosa.
• Another aim of the present invention is to provide novel glycomimetic compounds able to limit the pathogens adhesion and therefore with strong antimicrobial activity.
• Another aim of the present invention is to provide novel glycomimetic compounds able to inhibit biofilm formation and therefore of interest as anti-infectious compound against mucoid bacteria
• the present invention provides a calixarene-based glycosylated compound (I) having the formula :
• D is independently selected in the group comprising a -CH 2 - group, an oxygen atom (-0-), a sulphur atom (-S-), a sulfinyl group I ⁇ ) or a sulfonyl group (/ V ⁇ ),
• E is independently selected in the group comprising a hydrogen (-H), an alkyl having from 1 to
• E represents a -CO-R' ' ) wherein R' is a hydrogen atom, a hydroxyl group or an amino,
• A is independently selected in the group comprising an oxygen atom, a sulfur atom, a NH group or a (CH 2 ), group, i being an integer from 1 to 10,
• C is independently selected in the group comprising a hydrogen, an alkyl, an alkenyl, an alkynyl,
• n is an integer from 1 to 3
• V CH 2 , C 6 H 4 (phenyl "Ph"), CH2-CH 2 -0-CH 2! CH 2 -CO-NH-CH 2 ,
• n 1 to 15
• the Isugarj is a group having at least one carbohydrate moiety and is selecting in the group comprising :
• the calixarene-based glycosylated compound (I) as defined in the present application could also be defined as a glycomimetic compound comprising a core having at least one arm and at most four arms, the arm being represented by the following C group
• glycosylcholine refers more particularly to a compound (including physiologically acceptable salts thereof) that has high affinity for the Lec A, Lec B or both lectins from Pseudomonas aeruginosa bacteria.
• the originality of the present invention lies in the particularly structure of the linker which is constituted in two parts.
• the first part of the linker (located next the triazole moiety ) is an amide bond -(CONH)- ; this planar amide bond provides some rigidity to the first part of the linker and allows for optimal presentation of the arms (number varying from 1 to 4) towards the lectin binding site.
• the second part of the linker (located next the carbohydrate moiety) is variable and is represented by the structure (V) m -U as defined above.
• This second variable part of the linker can represents a group comprising also an amide bond, an ethyleneglycol moiety or an aromatic moiety.
• alkyl refers to a monoradical branched or unbranched saturated hydrocarbon chain having from 1 to 10 carbon atoms. This term is exemplified by groups such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n-hexyl, n-octyl, tert-octyl, n-decyl and the like.
• aryl refers to an unsaturated aromatic carboxylic group of from 6 to 20 carbon atoms, having a single ring or multiple condensed (fused) ring. This term is exemplified by groups such as phenyl, naphthyl and the like.
• the halogen atom is exemplified by a fluorine (F), a chlorine (CI), a bromine (Br) or an iodine (I).
• alkynyl refers to a monoradical of an unsaturated hydrocarbon preferably having from 2 to 10 carbon atoms and having at least from 1 to 2 sites of acetylene (triple bond) unsaturation. This term is exemplified by groups such as ethynyl (-C ⁇ CH), propargyl (-CH 2 -C ⁇ CH) and the like.
• the said calixarene-based glycosylated compound (I) can also be named "monovalent” calixarene-based glycosylated compound (I).
• the calixarene-based glycosylated compound (I) is named "divalent”.
• the calixarene-based glycosylated compound (I) is named "trivalent".
• the calixarene-based glycosylated compound (I) is named "tetravalent".
• the above mentioned sugar derivatives in the C group are selected in the group comprising :
• the above mentioned sugar derivatives in the C group are selected in the group comprising : -
• the sugar defined in the C group of the calixarene-based glycosylated compound (I) is selected wherein the
• the sugar is the ⁇ -D-galactosyl.
• defined in the C group of the calixarene-based glycosylated compound (I) is selected in the group comprising :
• the present invention provides a calixarene-based glycosylated compound (I) as defined previously, wherein two of the four C groups of the calixarene-based glycocosylated compound (I) represent the group of formula :
• the divalent calixarene-based glycosylated compound (I) thus above defined can be represented by one of the following substitution pattern:
• the present invention provides a calixarene-based glycosylated compound (I) as defined previously, wherein three of the four C groups of the calixarene-based glycosylated compound (I) represent the group of formula :
• the trivalent calixarene-based glycosylated compound (I) thus above defined can be represented by the following trisubstituted conformation :
• the present invention provides a calixarene-based glycosylated compound (I) as defined previously, wherein the four C groups of the calixarene-based glycosylated compound (I) represent the group of formula :
• the tetravalent calixarene-based glycosylated compound (I) thus above defined can be represented by one of the four following conformations :
• the present invention provides calixarene-based glycosylated compoundefined previously wherein D represents a -CH 2 - group, E represents an alkyl group which is the tert-butyl group and A defined in the B group of the calixarene-based glycosylated compound (I) represents an oxygen atom.
• calixarene-based glycosylated compound (I) according to invention lies to the fact that they can be obtained rapidly, according to adjustable and variable synthetics methodologies.
• the invention also provides a process for the preparation of a calixarene-based glycosylated compound (I) as defined above, characterized in that it comprises the following steps :
• X represents a protecting group selected in the group comprising acetate (CH 3 CO), benzoate (C 6 H 5 CO) or benzyl (C 6 H 5 CH 2 ), this protecting group being attached to the oxygen atom of the sugar hydroxyl groups (see the formula of the sugar as represented previously), by conjugation of the propargylated calix[4]arene (IV) as obtained in the previous step with carbohydrate derivative of formula (III) bearing an azido functionality next to the end of the linker
• the base which can be used with compounds (V) and (VI) can be NaH in DMF (cone conformation) or K 2 C0 3 then Cs 2 C0 3 . Then a mixture of partial cone and 1 ,3-alternate conformations is obtained which can be separated by silica gel column chromatography leading to the said propargylated calix[4]arene (IV).
• the present invention also provides a pharmaceutical composition characterized in that it comprises a calixarene-based glycosylated compound (I) as defined previously, in combination with pharmaceutically acceptable carriers or diluents.
• the pharmaceutical composition thus defined also comprises a therapeutic agent useful as anti-infectious against pathogens that use lectins in the first steps of infection.
• This therapeutic agent is for example a therapeutic agent for P. aeruginosa infection such as lung infections in cystic fibrosis patients, burns infection in hospital environment and bedsore infection in elderly houses.
• the present invention also provides a calixarene-based glycoconjugate compound (I) or a pharmaceutical composition as defined previously for use as anti-infectious directed against other pathogens using lectins for adhesion to host cells, such as influenza virus.
• the present invention concerns the use of a calixarene-based glycoconjugate compound (I) or a pharmaceutical composition as defined previously, for the manufacture of a drug intended to prevent or treat bacterial infections from pathogens that use lectins in the first steps of infection.
• Such a drug acts as anti-infectious directed against lectins from pathogens.
• calixarene-based glycosylated compounds (I), pharmaceutical compositions or drugs comprising these compounds are used by the respiratory or pulmonary way.
• These compounds, drugs or compositions are inhaled or instilled in the respiratory tract for preventing or treating infections from Pseudomonas aeruginosa, in particular in CF patients or patients being under respiratory assistance and which are often victims of nosocomial infections.
• calixarene-based glycosylated compounds (I), pharmaceutical compositions or drugs comprising these compounds are used by the local way or on a bandage for preventing or treating infections from Pseudomonas aeruginosa, in particular for burns or scabs.
• Figure 1 a is a general synthesis scheme illustrating the chemical structures and the preparation of the tetravalent calixarene-based glycosylated compound (I) wherein the four C
• Figure 1 b is a particular example of the general synthesis scheme of figure 1a, wherein in the tetravalent calixarene-based glycosylated compound (I) D represents a -CH2- group, E represents an alkyl group which is the tert-butyl group (f-Bu), A defined in the B group represents an oxygen atom, the linker, the sugar and X are as defined previously.
• D represents a -CH2- group
• E represents an alkyl group which is the tert-butyl group (f-Bu)
• a defined in the B group represents an oxygen atom
• the linker, the sugar and X are as defined previously.
• the calixarene-based glycosylated compound (I) obtained is tetravalent.
• the monovalent, divalent or trivalent calixarene-based glycosylated compound (I) are however obtained in the same way as the tetravalent.
• the selective alkylation of the phenolic groups is achieved with a base in the presence of alkyl halides and the remaining phenolic groups are then propargylated under the same conditions as for the transformation of (V) in (IV).
• linker] CO-NH-CH2-CH2-O-CH2-CH2
• linker] CO- NH-CH2-CO-NH-CH2-CH2CH2
• Step g) MeOH, H 2 0, Et 3 N, rt, 16 h ; Step h) : HOCH2CH2CI, SnCI 4 , CF 3 C0 2 Ag, CH 2 CI 2 , rt, 2 h ; Step i) : N-chloroacetyl-glycine, EDCI, HOBt,
• the reagents and conditions of the different steps are described below.
• Step a) Ac 2 0, C 5 H 5 N, DMAP, rt, 16 h ;
• Step b) H 2 , Pd-C 10%, CH 2 CI 2 , rt, 16 h ;
• Step c) BrCH 2 COBr, Et 3 N, CH 2 CI 2 , rt, 2 h ;
• Step d) NaN 3 , nBu 4 NI, DMF, 50°C, 16 h ;
• Step e) propargyl acetate, Cul, / ' Pr 2 NEt, DMF, 1 10°C, microwaves, 15 min ;
• Figure 3a represents synthesis schemes of tetravalent calixarene-based glycosylated compound (I) named “19” by using the carbohydrate azido-derivatives (III) named "3" prepared as illustrated in figure 2.
• Figure 3b represent synthesis schemes of glycomimetic (I) respectively named “21 “ (see fig. 3b-1 ), “23” (see fig. 3b-2) and “25” (see fig. 3b-3) by using the carbohydrate azido-derivative "8”.
• Fig. 3c represent synthesis schemes of glycomimetic (I) respectively named “27” (see fig. 3c-1 ), “29” (see fig. 3c-2) and “31 “ (see fig. 3c-3) by using the carbohydrate azido- derivative "12".
• Figure 4 represents curves for Enzyme-Linked Lectin Assay (ELLA). More particularly this figure illustrates the comparison of the competition effect of three different monovalent glycosylated compounds (I), named respectively 5, 10 and 14.
• the curve with the symbol ⁇ represents the compound 5.
• the curve with the symbol ⁇ represents the compound 10.
• the curve with the symbol ⁇ represents the compound 14.
• Figures 5a and 5b refer to the tetravalent calixarene-based glycosylated compound (I), named 19, for the inhibition of binding of LecA on a galactose-coated chip by SPR. More particularly figure 5a represents the sensorgrams obtained with increasing concentrations of compound 19.
• Figure 5b represents the inhibition curve derived from the different sensorgrams and used for the calculation of IC50 value.
• Figure 6 represents ITC thermogram of the interaction between LecA and glycocompound.
• the top represents the raw ITC data and the bottom the binding isotherm for the binding of compound 19 to LecA.
• Figure 7 displays the protective effect of different monosaccharides (glucose, galactose) and derivatives (compound 14) in a mice model with infection by P. aeruginosa.
• the permeability measures the deterioration of the alveolar barrier, i.e. the lung tissue damages caused by the bacterial infection.
• the compounds more particularly prepared here are tetravalent calixarene-based glycosylated compound (I) wherein :
• - D represents a -CH 2 - group
• - E represents an alkyl group which is the tert-butyl group
• the tetravalent glycomimetics compounds 19, 21 , 23, 25, 27, 29 are in the following conformations: - 1 ,3 alternate conformation for glycomimetics 19, 25 and 31 ,
• NMR spectra were recorded at 293 K, unless otherwise stated, using a 300 MHz or a 400 MHz Spectrometer. Shifts are referenced relative to deuterated solvent residual peaks.
• Infrared spectra were recorded using an FT-IR spectrometer with ATR attachment.
• High Resolution (LSIMS) mass spectra were recorded in the positive mode using a Thermo Finnigan Mat 95 XL spectrometer.
• ESI mass spectra were recorded in the positive mode using a Thermo Finnigan LCQ spectrometer.
• High resolution (HR-ESI-QTOF) mass spectra were recorded using a Bruker MicrOTOF-Q II XL spectrometer.
• MALDI-ToF mass spectra were recorded in positive ion reflectron mode using a Voyager DE-STR spectrometer (Applied Biosystem) with CHCA ((p-cyano-4-hydroxycinnamic acid, 10 g.L “1 in MeOH) and Nal (10 g.L “1 in acetone) as matrix.
• TLC Thin-layer chromatography
• Silica gel column chromatography was performed with silica gel Si 60 (40-63 ⁇ ). Optical rotation was measured using a Perkin Elmer polarimeter.
• the alkyne-functionalized compound, copper iodide, DIPEA and azido-derivative in degassed DMF were introduced into a Biotage Initiator 2-5 mL vial.
• the vial was flushed with argon and the solution was sonicated for 30 seconds.
• the vial was sealed with a septum cap and heated at 1 10°C for 15 min under microwave irradiation (solvent absorption level : High).
• solvent absorption level solvent absorption level : High
• the crude mixture was concentrated and co-evaporated with toluene 3 times before flash chromatography. If the product is not soluble in water at all, the mixture was diluted with EtOAc (250 mL).
• the acetylated glycoside or glycocluster (1 eq.) was suspended in distilled MeOH, ultra-pure water and ultra-pure triethylamine (5: 1 : 1 , v/v/v). The mixture was stirred under Argon at room temperature for 2 to 4 days. Solvents were evaporated, co-evaporated with toluene three times and the resulting white foam was dissolved in ultra-pure water (5 mL) and freeze-dried to afford pure glycomimetics.
• the filtrate was diluted with EtOAc to reach a total volume of 400 mL.
• the organic layer was washed with aq. NaHCOs (2x100 mL), water (2x100 mL), brine (100 mL) and dried (Na 2 S0 4 ). After concentration, the residue (yellow oil) was purified by silica gel flash chromatography (EtOAc) to afford the corresponding azido-functionalized glycoside 8 as a white foam (2.00 g, 78 %).
• IHA Hemagglutination
• HAA Hemagglutination Inhibition Assays
• the LecA lectin agglutinates red blood cells since they are covered by glycoconjugates.
• the glycomimetics inhibit this agglutination.
• hemagglutination inhibition assays were performed in U-shaped 96-well microtitre plates. Rabbit erythrocytes were bought from Biomerieux and used without further washing. The erythrocytes were diluted to a 4% solution in NaCI (150 mM). Lectin solutions of 2 mg/mL were prepared in Tris/HCI 20 mM, NaCI 100 mM and CaCI 2 100 ⁇ .
• the hemagglutination unit (HU) was first obtained by the addition of 25 ⁇ of the 4% erythrocyte solution to 25 ⁇ aliquots of sequential (two-fold) lectin dilutions. The mixture was incubated at 25°C for 60 minutes. The HU was measured as the minimum lectin concentration required to prevent hemagglutination. For the following lectin-inhibition assays, lectin concentrations of four times that of the hemagglutination unit were used, i.e. a concentration of 6 ⁇ g mL for LecA.
• 96-well plates are covered with polymer presenting galactose (which is the monosaccharide that is bound by LecA).
• galactose which is the monosaccharide that is bound by LecA.
• the lectin labelled with biotin is added in presence of competing glycomimetics. IC50 can be measured.
• ELLA experiments were conducted using 96-well microtitre plates (Nunc Maxisorb) coated with polymeric ⁇ -D-galactose (5 ⁇ g mL; Lectinity Holding, Inc., Moscow) diluted in carbonate buffer, pH 9.6 (100 ⁇ _) for 1 h at 37 °C. After blocking at 37 °C for 1 h with 100 ⁇ per well of 3% (w/v) BSA in PBS, plates were incubated at 37 °C for 1 h with 100 ⁇ of biotinylated LecA at 0.1 ⁇ g mL in the presence of serial dilutions of inhibitors.
• LecA was injected using running buffer consisting of HEPES 10 mM, NaCI 150mM, CaCI 2 10 mM, Tween P20 0.005%, pH 7.4. Inhibition studies consisted in the injection (150 ⁇ _, 10 ⁇ _ ⁇ , dissociation: 120 s) of incubated (>1 h, r.t.) mixtures of LecA (5 ⁇ ) and various concentrations of inhibitor (2-fold cascade dilutions). For each inhibition assay, LecA (5 ⁇ ) without inhibitor was injected to observe the full adhesion of the lectin onto the sugar-coated surface (0% inhibition). The CM5 chip was fully regenerated by successive injections of D- Galactose (2x30 ⁇ , 100 mM in running buffer).
• Binding was measured as RU over time after blank subtraction, and data were then evaluated using the BIAevaluation Software, version 4.1.
• IC 50 evaluation the response (Req - fitted) was considered as the amount of lectin bound to the sugar surface at equilibrium in the presence of a defined concentration of inhibitor.
• Inhibition curves were obtained by plotting the percentage of inhibition against the inhibitor concentration (on a logarithmic scale) by using Origin 7.0 software (OriginLab Corp.) and IC 50 values were extracted from sigmoidal fit of the inhibition curve.
• ITC Isothermal Titration Microcalorimetry
• the method allows for a direct measurement of the affinity between the glycomimetics and the LecA lectin.
• the dissociation constant is measured.
• recombinant lyophilized LecA was dissolved in buffer (0.1 M Tris-HCI, 6 ⁇ CaCI 2 , pH 7.5) and degassed (see Supp. Info, for concentration details). Protein concentration was checked by measurement of optical density using a theoretical molar extinction coefficient of 28000. Carbohydrate ligands were dissolved directly into the same buffer, degassed, and placed in the injection syringe. ITC was performed with a VP-ITC MicroCalorimeter from MicroCal Incorporated. PA-IL was placed into the 1.4478-mL sample cell, at 25°C. Titration was performed with 10- ⁇ injections of carbohydrate ligands every 300 s. Data were fitted with MicroCal Origin 7 software, according to standard procedures. Fitted data yielded the stoichiometry (n), the association constant (K a ) and the enthalpy of binding ⁇ AH).
• thermodynamic parameters i.e. changes in free energy, AG, and entropy, AS
• T is the absolute temperature
• R 8.314 J.mol ⁇ 1 .K ⁇ 1 .
• Two or three independent titrations were performed for each ligand tested.
• compound 14 is the most efficient inhibitor (as illustrated in Figure 4). All tetravalent glycoconjugates inhibit the binding of LecA to galactosylated surface at low concentration. The most efficient compounds are 27 and 29 with IC50 in sub micromolar range.
• Table 3 The values given in Table 3 are the IC 50 values for the inhibition of label-free LecA binding to a galactosylated chip surface using Plasmon Surface Resonance.
• mice were briefly anesthetized with inhaled sevoflurane. For each mouse, 50 I of a bacterial inoculum of 5x10 8 CFU/ml was instilled into the lungs through a gavage inserted into trachea via the oropharynx. The alveolar capillary barrier permeability was evaluated by measuring residual 125 l-albumin instilled intratracheally as an alveolar protein tracer in the lungs and its leakage and accumulation in the plasma aftert 6 h after infection. The intratracheal instillate was a mixture of 1 C ⁇ of 125 l-labeled albumin and 5% bovine albumin together with the P.
• aeruginosa inoculate and different monosaccharides or glycocompounds.
• the total radioactivity in the instillate was measured. Fifty microliters of instillate was inoculated into the lungs of each anesthetized mouse. Six hours after instillation, mice were anesthetized with pentobarbital given intraperitoneally. The blood was collected by carotid arterial puncture, and a sternotomy was performed to harvest and measure the radioactivity in the lungs, trachea, and stomach. The quantity of 1251-albumin that leaked into the circulation was calculated by multiplying the activity in a blood sample by the volume of blood. 2) Biological results
• Compound 14 has been compared with two monosaccharides : glucose and galactose, in animal models assays.
• the compounds (glucose, galactose and compound 14) have been co- instillated in mice lungs together with infecting concentration of Pseudomonas aeruginosa.
• the protection that these compounds bring to the lung was estimated by measuring the integrity of the alveolar barrier. For this, labelled albumin was circulated in the blood and the quantity that leaked through the alveoles barriers to the lung was estimated.
• Figure 7 displays the protective effect of glucose, galactose and compound 14 in a mice model with infection by P. aeruginosa.
• the permeability measures the deterioration of the alveolar barrier, i.e. the lung tissue damages caused by the bacterial infection.
• the monovalent glycoconjugate compound 14 appears to be more efficient than galactose. Its co-instillation results in approximately 50% reduction of lung damages when compared to the control experiment with instillation of bacteria without sugar. The result indicates that compound 14 efficiently protect the lung tissues from destruction by P. aeruginosa and resulting systemic infection.

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• 2010
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  • 2010-12-10 EP EP10812804.2A patent/EP2649085B1/en not_active Not-in-force
  • 2010-12-10 ES ES10812804.2T patent/ES2524363T3/es active Active
  • 2010-12-10 WO PCT/IB2010/055741 patent/WO2012076934A1/en not_active Ceased

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