Serotonin Receptor Antagonists For Treating Arthritis

  • Published: Jul 31, 2008
  • Earliest Priority: Jan 22 2007
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Serotonin receptor antagonists for treating arthritis

The present invention relates to serotonin receptor antagonists for treating inflammatory arthritis and related conditions. The present invention also relates to a kit comprising a pharmaceutical composition comprising a serotonin receptor antagonist and instructions indicating that the composition is for use in treating inflammatory arthritis and related conditions. In addition, the present invention relates to a method of treating inflammatory arthritis and related conditions comprising administration of a serotonin receptor antagonist. The method is preferably carried out on a subject in need of treatment. The inflammatory arthritis is preferably rheumatoid arthritis.

Rheumatoid arthritis is a chronic inflammatory disease occurring in 0.5%- 1% of the population. This disease affects the joints and is characterized by thickening of the synovial membrane. This disease leads to progressive debilitation in joint function which results in pain, disability, loss of man power and shorter life expectancy. In addition there are a number of similar related conditions; psoriatic arthritis, juvenile arthritis, ankylosing spondelytis, Crohn's disease and psoriasis.

Current treatments for rheumatoid arthritis have a number of disadvantages, including expense and/or severe side effects. At present, steroids such as dexamethasone and methyl-prednisolone, are widely used in the treatment of rheumatoid arthritis. While treatment with steroids can be effective, there are a number of serious side effects. These side effects include hypertension, growth deficiencies in younger patients, osteoporosis, cataracts, psychosis, elevated blood sugar, glaucoma, etc. In addition, some patients are resistant to long-term use of steroids or become so with time.

New and alternative treatments currently used for rheumatoid arthritis are based on biologicals such as antibodies and soluble receptors. The most widely used of these is based on blocking TNF function with neutralizing antibodies or soluble receptors and has defined TNF as a key pathway in the inflammatory processes in rheumatoid arthritis. This type of anti-TNF therapy has been successful in the treatment of a number of diseases, with a substantial proportion of patients (approximately 60%) showing significant clinical benefit. Besides treating the inflammation, anti-TNF therapy also prevents joint destruction and thus is considered to have disease modifying anti-arthπtic drug (DMARD) activity However, it is extremely expensive and this places a heavy financial burden either on the patient or the healthcare system or both and this seπously limits availability. Many patients in the developed world and the majority in the developing world are not able to afford this treatment. In addition, possible side effects of anti-TNF therapy include anaphylaxis and cytopenia Moreover systemic neutralisation of TNF leads to increased susceptibility to infection and the long-term effects are still unknown. Currently it is not possible to take anti- TNF drugs orally, which is a disadvantage. Moreover of those patients that do respond approximately 50% will become refractory to treatment in 2 years due to the development of immunity to the biological treatment.

Another class of drugs are the disease modifying anti-rheumatic drugs (DMARX)S). An example of these is methotrexate, an anti-metabolite drug, which is widely used for the treatment of rheumatoid arthritis, psoπatic arthritis and psoπasis. Methotrexate has been successful in the treatment of these diseases, but can cause substantial side effects, such as severe skin reaction, infections such as pneumonia, severe damage to liver, kidneys, lungs and gastrointestinal tract Again a significant number of patients do not respond or become refractory with time.

A number of DMARD pharmaceutical agents containing gold are also used in the treatment of rheumatoid arthritis. Examples of such agents include gold sodium thiomalate and auranofin Potential side effects from being treated with antiinflammatory gold agents are oral ulcers, altered taste, seπous skin rashes, renal problems, inflammation of the intestines (enterocolitis), liver injury and lung disease. Furthermore, resistance to gold has been known to develop in patients.

A further class of drugs are the non-steroidal anti-inflammatory drugs (NSAID's). These are used to alleviate symptoms but not modify disease progression and includes the Cox 2 inhibitors "VIOXX"®, (a registered trademark of Merck & Co., Inc) and "CELEBREX" ®, (a registered trademark of G.D. Searle & Co). However there is major concern about the safety of these drugs with evidence of increased cardiovascular risk.

As a result of lack of efficacy, development of resistance, unacceptable side-effects and expense of existing treatments and route of administration, it is hugely desirable to find alternative treatments for rheumatoid arthritis. Thus there is a huge unmet medical need for an orally-available, well tolerated, inexpensive drug that could selectively block the production of TNF associated with pathological inflammation found in RA and related conditions.

Serotonin receptor antagonists are well known for use in the treatment of depression, nausea and psychotic disorders. Past work in this area has indicated that at least one serotonin receptor antagonist, mianserine, actually increases inflammatory arthritis (Letter to the editor of the British Journal of Rheumatology, 1991).

The first aspect of the present invention provides a serotonin receptor antagonist for treating inflammatory arthritis and related conditions.

The inflammatory arthritis is anti-TNF responsive arthritis, as are the related conditions psoriatic arthritis, juvenile arthritis, ankylosing spondelytis, Crohn's disease and psoriasis. These drugs are envisaged to be useful in diseases where treatment with anti-TNF has shown to be beneficial e.g. Crohn's disease and psoriasis, but not useful in diseases where anti-TNF has been shown to be ineffective or to exacerbate disease, e.g. systemic lupus erythematosus, multiple sclerosis and ulcerative colitis. Mianserine is unable to inhibit LPS induced TNF indicating that mianserine does not possess general anti-inflammatory properties and thus would not be expected to be beneficial in the treatment of sepsis where TNF is produced by LPS stimulation. In a preferred embodiment the inflammatory arthritis is rheumatoid arthritis and the related conditions are psoriatic arthritis, juvenile arthritis, ankylosing spo'ndelytis, Crohn's disease and psoriasis.

A serotonin receptor antagonist of the invention is any compound that inhibits a member of the serotonin receptor family. This includes serotonin receptor inverse agonists.

As is known in the art, a serotonin receptor antagonist is a compound that prevents the actions of serotonin (5-hydroxytryptamine or 5-HT) by binding to a serotonin receptor. Serotonin receptor antagonists include inverse agonists. A serotonin receptor inverse agonist is a drug which binds to a serotonin receptor producing an antagonistic effect but additionally exerts a different pharmacological effect to serotonin.

A serotonin receptor antagonist of the invention inhibits TNF production.

Information on determining serotonin receptor antagonism can be found in Cohen et al., J. Pharmacol. Exp. Ther. (1988) 244 (1): 106.

5-HT receptors are receptors for the neurotransmitter and peripheral signal mediator serotonin, also known as 5-hydroxytryptamine or 5-HT. Serotonin (5-HT) receptors are divided into seven distinct classes 5-HTi-5-HT7 comprising at least 14 distinct members. It is through these receptors that serotonin produces its effects.

In one embodiment, the serotonin receptor antagonist is a 5-HTi, 5-HT2, 5-HT3, 5- HT4, 5-HT5, 5-HT6 or a 5-HT7 receptor antagonist.

Compounds of the invention can be promazine (including promazine hydrochloride), ketanserine (including ketanserine tartrate), amoxapine, maprotiline, mianserine (including mianserine hydrochloride), mirtazapine, nefazodone, setiptiline, trazodone, ritanserin, spiperone, methiothepin, GR55562, SB 224289, chloropromazine, clozapine, haloperidol, loxapine, risperidone, mesulergine, cyproheptadine, ML 10375, olanzapine, WAY 100635, GRl 13808, memantine, metoclopramide, renzapride, ondansetron, alosetron, agomelatine, pizotifen, metergoline, ergotamine, cyamemazine, BRL43694A, RS100235, Ro630563, SB271046, SB357134, SB258719, SB269970, cyamemazine, SB242084, RS102221, granisetron, SB204070, tropisetron, SB236057, BRL15572, MDL 100907, S B 200646, SB204741, metitepine, ricasetron, SR46349-B, ICS 205-930, clotiapine.

The use may be of combinations of two or more serotonin receptor antagonists, which may be for simultaneous, separate or sequential use.

The serotonin receptor antagonists may be used in combination with a further antiinflammatory agent. Administration of the serotonin receptor antagonists and other anti-inflammatory agent can be simultaneous, separate and/or sequential. The serotonin receptor antagonists, in combination with another pharmaceutical agent, can act additively or synergistically.

The other anti-inflammatory agent may be termed a non-steroidal anti-inflammatory agent (NSAID), a disease modifying anti-rheumatic drug (DMARD), a biological agent (biologicals), a statin (including HMG-CoA reductase inhibitors such as simvastatin), a steroid, an immunosuppressive agent, a salicylate and/or a microbicidal agent. Non-steroidal anti-inflammatory agents include anti-metabolite agents (including methotrexate) and anti-inflammatory gold agents (including gold sodium thiomalate, aurothiomalate or gold salts, such as auranofin). Biologicals include anti-TNF agents (including adalimumab, etanercept, infliximab, anti-EL-1 reagents, anti-IL-6 reagents, anti-B cell reagents (retoximab), anti-T cell reagents (anti-CD4 antibodies), anti-EL-15 reagents, anti-CLTA4 reagents, anti-RAGE reagents), antibodies, soluble receptors, receptor binding proteins, cytokine binding proteins, mutant proteins with altered or attenuated functions, RNAi, polynucleotide aptemers, antisense oligonucleotides or omega 3 fatty acids. Steroids include cortisone, prednisolone or dexamethasone. Immunosuppressive agents include rvlπnsporin, FK506, rapamycin, mycophenolic acid. Salicylates include aspirin, sodium salicylate, choline salicylate and magnesium salicylate Microbicidal agents include quinine and chloroquine For example, the serotonin receptor antagonist may be administered in combination with one or more of an NSAID, DMARD, or immunosuppressant

The further anti-inflammatory agent is administered by any appropπate route, for example oral (including buccal or sublingual), suppositoπes, topical (including buccal, sublingual or transdermal), or parenteral (including subcutaneous, intramuscular, intravenous or intradermal) route Where the further anti-inflammatory agent is administered orally, it may be administered as part of the same composition as the serotonin receptor antagonists

The serotonin receptor antagonists of the present invention are those serotonin receptor antagonists which are non-toxic to living cells

The present invention also provides the use of a serotonin receptor antagonist in the manufacture of a medicament for treating inflammatory arthritis and related conditions

The second aspect is a kit comprising a pharmaceutical composition compπsing a serotonin receptor antagonist and instructions indicating that the composition is for use in treating inflammatory arthritis and related conditions

Compositions in accordance with the invention may be supplied as part of a sterile, pharmaceutical composition which will normally include a pharmaceutically acceptable earner This pharmaceutical composition may be in any suitable form It may be provided in unit dosage form and will generally be provided in a sealed container The kit of the invention may comprise a plurality of said unit dosage forms

The oral pharmaceutical compositions may be presented as discrete units such as capsules or tablets, as powders or granules, as solutions, syrups or suspensions (in aqueous or non-aqueous liquids; or as edible foams or whips; or as emulsions). Suitable excipients for tablets or hard gelatine capsules include lactose, maize starch or derivatives thereof, stearic acid or salts thereof. Suitable excipients for use with soft gelatine capsules include for example vegetable oils, waxes, fats, semi-solid, or liquid polyols etc.

For the preparation of solutions and syrups, excipients which may be used include for example water, polyols and sugars. For the preparation of suspensions oils (e.g. vegetable oils) may be used to provide oil-in-water or water in oil suspensions.

The pharmaceutical compositions may contain preserving agents, solubilising agents, stabilising agents, wetting agents, emulsifiers, sweeteners, colourants, odourants, salts, buffers, coating agents or antioxidants. They may also contain further therapeutically active agents.

Route of administration may include; parenterally (including subcutaneous, intramuscular, intravenous, by means of, for example a drip patch), some further suitable routes of administration include (but are not limited to) oral (including buccal and sublingual), rectal, nasal, topical, infusion, vaginal, intradermal, intraperitoneally, intracranially, intrathecal and epidural administration or administration via oral or nasal inhalation, by means of, for example a nebuliser or inhaler, or by an implant.

For administration via the oral or nasal inhalation routes the may be delivered using a mechanical form including, but not restricted to, an inhaler or nebuliser device.

Further, where the oral or nasal inhalation routes are used, administration is by a SPAG (small particulate aerosol generator) may be used.

Dosages of the substances of the present invention can vary between wide limits, depending upon the condition to be treated, the health of the individual to be treated, etc. and a physician may determine appropriate dosages to be used. The dosage may be repeated as often as appropriate. The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. The amount of active ingredient which can be combined with a carrier material to produce a single dosage form will vary depending upon the host being treated, the particular mode of administration. The amount of active ingredient which can be combined with a carrier material to produce a single dosage form will generally be that amount of the compound which produces a therapeutic effect.

The compositions and uses described in this application are envisaged to have human, animal and veterinary applications. They are preferably applicable to mammals, in particular humans but are also applicable for use in production animals, in particular sheep, cows, pigs, chickens and goats, as well as companion animals, in particular cats and dogs and sporting animals, such as horses.

The third aspect of the invention is a method of treating inflammatory arthritis and related conditions comprising administration of a serotonin receptor antagonist. In the third aspect of the invention, the method is preferably carried out on a subject in need of treatment.

In the present invention, the term "treatment" includes prophylactic treatment (i.e. prevention). In most circumstances, prevention of inflammatory arthritis or a related condition is unlikely to be carried out. Usually, it is only when the presence of inflammatory arthritis or a related condition is diagnosed in a subject that prevention means are applied. However, prophylactic treatment may be appropriate if there is a known family history of significant inflammatory arthritis or a related condition or if tests (e.g. genetic tests) identify that an individual has a predisposition to inflammatory arthritis or a related condition.

The preferred embodiments, as described for the first aspect of the invention, are the same for other aspects of the invention mutatis mutandis.

The present invention is described with references to the drawings, in which: Figure 1 illustrates inhibition of spontaneous cytokine release from RA synovial membrane cultures by mianserine hydrochloride, promazine hydrochloride and ketanserine tartrate. Graph (A) illustrates inhibition of TNF levels (n=16) by 30μg/ml mianserine hydrochloride as measured by ELISA. Each point represents an individual donor. Graph (B) illustrates a dose dependent inhibition of TNF by mianserine hydrochloride and promazine hydrochloride. Graph (C) illustrates dose dependent inhibition of TNF in RA synovial membrane cultures treated with lOμM or lOOμM ketanserine tartrate. ***= P<0.001

Figure 2 illustrates inhibition of disease progression in the CIA model of rheumatoid arthritis by mianserine hydrochloride. Graph (A) illustrates clinical score, Graph (B) illustrates paw swelling, Graph (C) illustrates histology scoring and Graph (D) illustrates histology images of a joint. The statistics were calculated using a Mann- Whitney one tailed test **=P<0.01, *=P<0.05, n=7, for the 10mg/kg group versus the vehicle control.

Figure 3 Graph (A) illustrates TNF production in primary human macrophages stimulated with TLR ligands in media alone or in the presence of 30μg/ml mianserine hydrochloride. Graph (B) illustrates inhibition by mianserine hydrochloride of TNF production in CpG stimulated murine RAW264.7 macrophages (n=2). Graph (C) illustrates inhibition by mianserine hydrochloride of NF-κB activity activated by the TLR3 ligand poly IC (20μg/ml) but not by the TLR4 ligand LPS (lOng/ml) in rheumatoid synovial fibroblasts (n=3), *=P<0.05.

Figure 4 Graph (A) illustrates TNF production from human macrophages stimulated with lμg/ml R848 in the media alone or in the presence of 30μg/ml mianserine hydrochloride or 30μg/ml promazine hydrochloride. Graph (B) illustrates IP-10 levels from macrophages stimulated with 20μg/ml poly IC, in media alone or in the presence of 30μg/ml mianserine hydrochloride or 30μg/ml promazine hydrochloride. Figure 5 illustrates that TLR3, 7, 8 and 9 are expressed in the rheumatoid synovial membrane cultures but only TLR3 and 8 induce TNF production. Graph (A) RT-PCR illustrates the presence of TLR3, TLR7, TLR8 and TLR9 mRNA in 3 separate donors. Graph (B) illustrates FACS analysis of cell surface and intracellular expression of TLR3, TLR8 and TLR9. Representative histogram plots of 3 independent donors are shown. Graph (C) illustrates TNF production in rheumatoid membrane synovial cells after stimulation with 20μg/ml Poly IC (TLR3), lμg/ml imiquimod (TLR7), lμg/ml R-848 (TLR7/8) and 2μM CpG (TLR9).

Figure 6 illustrates the mechanism of inhibition of TNF by mianserine hydrochloride in RA membrane cell may be due to inhibition of the TLRs. Addition of chloroquine to RA membrane cell cultures for 24 hours (n=4). *=P<0.05

Figure 7 (A) illustrates that GBR 12909, Clotrimazole, Propidium iodide (PI) and mianserine hydrochloride do not inhibit TNF production in macrophages stimulated with LPS. Graph (B) illustrates that only mianserine hydrochloride and promazine hydrochloride inhibit R-848 induced TNF. Graph (C) illustrates that GBR 12909,

Clotrimazole, Propidium iodide, mianserine hydrochloride and promazine hydrochloride are all able to inhibit Poly IC induced IP-10. Graph (D) illustrates GBR 12909, Clotrimazole, Propidium iodide, do not inhibit TNF production in the rheumatoid arthritis synovial membrane culture while mianserine hydrochloride does inhibit.

Figure 8 illustrates that the serotonin receptor antagonists; ondansetron, metergoline, loxapine, ritanserin, methiothepin and mianserine inhibit spontaneous TNF production from human RA synovial membrane cultures, as measured by ELISA.

Figure 9 illustrates competitive inhibition of R-848 by mianserine. Primary human macrophages were incubated with media containing 0.3, 1, 10 or 20 μg/ml R-848 with media alone or in the presence of either (A) 2.5, 5 or 10 μg/ml mianserine or (B) 5 μg/ml mianserine for 6 hours. TNF production was measures by ELISA. Data was pooled from three separate donors. Results are shown as (A) percentage of the maximal TNF response or (B) the percentage inhibition of TNF production.

Figure 10 illustrates inhibition of R-848 induced TNF production from primary human macrophages and spontaneous TNF production from RA cultures by ondansetron. (A) illustrates a dose dependant inhibition of R-848 induced TNF production from human macrophages. (B) illustrates that ondansetron significantly inhibits R-848 induced TNF but not LPS induced TNF in human macrophages. (C) illustrates significant inhibition of spontaneous TNF production from human RA synovial cultures by ondansetron (n=5) *=P<0.05.

Figure 11 illustrates that serotonin (5-HT) does not inhibit TNF production induced by R-848 as measured by ELISA.

Figure 12 illustrates that ondansetron, metergoline, loxapine, ritanserin and methiothepin inhibit TNF production induced by R-848 from primary human macrophages, as measured by ELISA.

Figure 13 illustrates that simvastatin and mianserine inhibit spontaneous TNF production from human RA synovial membrane cultures as measured by ELISA and produce an additive effect when added together.

The present invention is described with reference to the following non-limiting examples:

Examples

General Materials and Methods

Reagents

Cell culture reagents used were Penicillin-Streptomycin, RPMI 1640 and DMEM obtained from Cambrex (Belgium), Indomethacin from Sigma (USA) and FBS from PAA (Austria). The TLR ligands used were chloroform extracted Escherichia coli (E coh) LPS and resiquimod (R-848), muπne CpG (ODN 1826), human CpG (ODN 2006) and lmiquimod from Invivogen (USA), Macrophage-activating lipopeptide (Malp-2), Flagelhn (puπfied) and were from Alexis (UK) Mianseπne hydrochloride was purchased from Sequoia research products (UK) Chloroquine diphosphate salt, Clotrimazole, Propidium iodide (PI), GBR 12909 and promazine hydrochloride were purchased from Sigma (USA) Ketanseπne tartrate was purchased from Tocπs bioscience (UK) Pam3cys-ser(lys)4.3HCl (Pam3) was from Alexis (UK). The antibodies used for FACS were FITC conjugated CC-TLR3, α-TLR8 and α-TLR9 from Imgenex (USA) and a IgGl-FITC control from BD Pharmingen

Reverse transcriptase-polymerase chain reaction (RT-PCR) RNA was isolated using the Qiagen RNA Blood isolation kit (Qiagen, Valencia, CA) according to the manufacturer's instructions. Total RNA was reverse transcπbed with Superscπpt II RNase H reverse transcnptase (Gibco Life Technologies, Carlsbad, CA) and oligo (dT) primer. For human TLR3 amplification, the primers 5'- GCAAACACAAGCATTCGGAATCT-3' and 5'-

TTGAAGGCTTGGGACCAAGGCA-3' were used with an annealing temperature of 62°C. For human TLR7 amplification, the pπmers 5'- TCTACCTGGGCCAAAACTGTT-3' and 5'- GGCACATGCTGAAGAGAGTTA-S1 were used with an annealing temperature of 6O0C. For human TLR8 amplification, the primers 5'- CCGACTTGGAAGTTCTAGATC-S1 and 51- AATGCTTCATTTGGGATGTGCT-3' were used with an annealing temperature of 600C. For human TLR9 amplification, the pπmers 5'- GTGCCCCACTTCTCCATG- 3' and 5'- GGCACAGTCATGATGTTGTTG-S' were used with an annealing temperature of 55°C Amplification was performed in a Dyad PCR machine (MJ Instruments) Subsequent PCR amplification consisted of 35 cycles

ELISA (enzyme-linked immunosorbent assay)

Macrophages or RA synovial membrane cell cultures were stimulated with lOng/ml chloroform-extracted LPS, 10ng/ml Pam3, 10ng/ml Flagelhn, 10ng/ml Malp-2,

20μg/ml poly IC, 2μM CpG (human/mouse) or lμg/ml R-848 in complete media for 6h. Supernatants from RA cultures were harvested after 24 hours. All reagents other than LPS were free from LPS contamination as assessed using the limulus amebocyte lysate (LAL) assay from Cambrex (USA).

Sandwich ELISAs were employed to measure TNF, (Pharmingen, UK), IP-10 (R&D, USA) and IL- lβ (Bioscource, USA). Absorbance was read on a spectrophotometric ELISA plate reader (Labsystems Multiscan Biochromic) and analyzed using Ascent software V2.6 (Thermo Labsystems, Cambridge, United Kingdom). All results are expressed as the mean cytokine concentration ± SD obtained from triplicate cultures per condition. Cell viability was not significantly affected over this time period when examined by the 3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay (Sigma).

Luciferase Assay

Synovial fibroblasts were cultured in a 96-well plate, infected with recombinant adenovirus containing a NF-κB Luciferase reporter gene at a MOI of 200: 1. The cells were allowed to rest for 24h prior to stimulation. Cells were preincubated with 30μg/ml mianserine hydrochloride for 30 minutes, then stimulated with lOng/ml LPS or 20μg/ml Poly IC for 6h. The cells were then washed once in PBS and lysed with lOOμl of CAT lysis buffer (0.65%(v/v) of Nonidet P-40, 1OmM Tris-HCl pH 8, O.lmM EDTA pH 8, 15OmM NaCl). 50 μl of cell lysate were mixed with 120μl luciferase assay buffer (25mM Tris-phosphate pH 7.8, 8mM MgCl2, ImM EDTA, l%(v/v) Triton X-100, l%(v/v) glycerol, ImM DTT, 0.5mM ATP) in the well of a luminometer cuvette strip. Luciferase activity was measured with a Luminometer (Thermo Labsystems, U.K.) by adding 30/xl of luciferin (Bright-Glo luciferase assay system; Promega, Madison, WI) per assay point.

Statistical methods

Mean, standard deviation (SD) and statistical significance were calculated using GraphPad version 3 (GraphPad Software Inc., USA). For statistical analysis, a one tailed student's t-test of paired data was used with a 95% confidence interval and the λ Λnnn -Whitney test. Cell culture

RA synovial membrane cells were isolated from patients undergoing joint replacement surgery as previously described (Foxwell et al., Proc. Natl. Acad. Sci. USA 95,8211-8215, 1998). All patients gave written informed consent and the study was approved by the local ethics committee. Immediately after isolation, cells were used for mRNA analysis, stained by FACS or cultured at IxIO5 cells/well in 96-well tissue culture plates (Falcon, UK) in RPMI 1640 containing 10% (v/v) FBS and 100 U/ml penicillin/streptomycin. Primary human synovial fibroblasts were cultured as described previously (Butler et al. Eur. Cytokine Netw. 5:441-8, 1994). Peripheral blood monocytes were isolated and cultured as previously described (Foxwell et al., Proc. Natl. Acad. Sci. USA 95,8211-8215, 1998). Macrophages were derived from monocytes after differentiation for 4 days with 100 ng/ml M-CSF (PeproTech, UK). The mouse macrophage cell line RAW 264.7 was maintained in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum.

Example 1

Rheumatoid arthritis synovial membrane cells were cultured for 24 hours in the presence of media alone or media containing 30μg/ml mianserine hydrochloride. Supernatants were harvested and levels of cytokines (A) TNF (n=16) were measured by ELISA. Addition of mianserine hydrochloride at the time of culture led to a significant decrease in the levels of TNF (59%±13, ρ=0.0007) (Figure 1, Graph A). A students paired t-test was used to analyse the data.

Rheumatoid arthritis synovial membrane cells were also cultured in the presence of media alone or media containing lOμg/ml, 20μg/ml and 30μg/ml mianserine hydrochloride or promazine hydrochloride and levels of TNF were measured. TNF activity was dose dependently inhibited in cells treated with mianserine hydrochloride and promazine hydrochloride (see Figure IB).

Rheumatoid arthritis synovial membrane cells were also cultured in the presence of m^Hia alone or media containing lOμM, lOOμM ketanserine tartrate and levels of TNF were measured. TNF activity was dose dependent!;/ inhibited in cells treated with ketanserine tartrate (see Figure 1C).

These results illustrate that mianserine hydrochloride inhibits the spontaneous release of TNF and from rheumatoid synovial membrane cultures. In addition, these results show that ketanserine tartrate and promazine hydrochloride can also inhibit spontaneous TNF production in rheumatoid synovial membrane cultures.

Example 2 The murine CIA model has been shown to be clinically similar to human rheumatoid arthritis with a comparable synovitis, bone erosion and panus formation.

Male DBA mice (8-10 weeks of age) were immunized at the base of the tail intradermally with 200μg type II collagen emulsified in CFA (Difco Laboratories, West Molesey, U.K.). The onset of arthritis was considered to be the day that erythema and/or swelling were first observed, and arthritic mice were given a daily clinical score per limb from 0 to 3, with 0 = normal, 1 = slight erythema and swelling, 2 = pronounced edematous swelling and 3 = joint deformity with ankylosis, resulting in a maximum score of 12 per animal. Mianserine treatment started on the day of onset and was administered daily for 7 days. Paw swelling was assessed by measuring hind paw thickness using calipers.

The experiment was started at the onset of arthritis (day 1). Mice were given an interperitoneal injection of vehicle (PBS), 4mg/kg or 10 mg/kg of mianserine hydrochloride once a day for 7 days. Mice were assessed for (Figure 2A) clinical score and (Figure 2B) paw swelling on a daily basis.

Mice treated with mianserine hydrochloride at the day of onset of arthritis (day 1) exhibited an attenuated disease progression over a 7 day period. Disease pathogenesis was assessed by measuring clinical score. The mice treated with mianserine hydrochloride showed a significant improvement to the control group from day 3 onwards (Figure 2, Graph A, B). This effect of mianserine hydrochloride was dose dependent as 4mg/kg did not produce as great an effect as the lOmg/kg group. This was also reflected in the measurement of hind paw swelling that also showed a significant improvement throughout the study between the two groups for the 10mg/kg group whilst the 4mg/kg group showed no significant improvement (Figure 2, Graph B). Histology samples taken from the hind paws of mice treated with mianserine hydrochloride showed a clear reduction in both bone destruction and cell infiltration into the joint (Figure 2, Graph D) confirming the histology scoring from pooled data (Figure 2, Graph C) which shows an improvement in the score at 4mg/kg mianserine hydrochloride group with a significant effect measured in the 10 mg/kg group.

These results illustrate that mianserine hydrochloride inhibits disease progression in the CIA model of rheumatoid arthritis.

Example 3

Primary human macrophages, murine RAW 264.7 cells and synovial fibroblasts were incubated with 30μg/ml mianserine hydrochloride for 30 minutes and then stimulated for 6 hours with TLR ligands (R-848, Pam3, LPS, flagellin, malp-2, poly IC or CpG). Human macrophages showed a decreased production of TNF in response to R-848 but not Pam3, LPS, flagellin or Malp-2 in the presence of mianserine hydrochloride

(Figure 3, Graph A).

Murine RAW 264.7 cells were used to examine CpG induced TNF, as unlike human macrophages they respond to CpG, a TLR9 ligand. Mianserine hydrochloride was able to inhibit TNF production in these cells on stimulation with CPG (Figure 3, Graph B).

To measure activation of TLR3, synovial fibroblasts were infected with a NF-κB reporter virus. Cells were stimulated with LPS as a control and poly IC to activate TLR3. Mianserine hydrochloride was able to significantly inhibit TLR3 induced NF- KB activation but had no effect on LPS induced NF-κB activation (Figure 3, Graph C)

This shows that signaling from toll-like receptors (TLRs) 3, 8 and 9 are selectively inhibited by nuanseπne hydrochloride and that it does not have general antiinflammatory properties as it unable to inhibit TNF stimulated by activation of the other TLRs

Example 4 Inhibition of TLRs 3 and 8 by miansenne hydrochloπde was also observed for other serotonin receptor antagonists Promazine hydrochloπde decreased TNF production in human macrophages stimulated by the TLR7/8 ligand R-848 (Figure 4, Graph A). Figure 4B illustrates that promazine hydrochloπde, like miansenne hydrochloπde inhibits TLR3 induced signalling in human macrophages (Figure 4, Graph B).

Example 5

TLR3, 7, 8 and 9 are expressed in human RA synovial tissue mRNA from synovial tissue was extracted, DNAase treated and then analysed by RT-PCR Expression of message for TLR3, 7, 8 and 9 was detected by RT-PCR from the mixed population of cells in human rheumatoid synovial tissue in three unrelated donors 1-3 (Figure 5, Graph A).

TLR3, 8 and 9 were further investigated using FACS Cells were washed, then blocked with 10% human serum in PBS containing 0 01% azide for 30 minutes at 40C or for intracellular staining cells were fixed in 2% paraformaldehyde and permeabihsed with 0 1% saponin (Sigma, USA) before blocking. Cells were then incubated with FITC conjugated α-TLR3, α-TLR8, α-TLR9 or isotype controls for lhr at 4°C and then washed before analysis on a Becton-Dickinson LSR flow cytometer A directly conjugated antibody was not available to examine TLR7 expression TLR3, 8 and 9 protein expression was detected at low levels on the cell surface but was more readily detected upon intracellular staining (Figure 5, Graph B).

To check if these TLRs were functional in synovial membrane cultures, cells were stimulated with the appropπate TLR hgands at the time of seeding the cells (Figure 5, Graph C). These cells spontaneously release cytokines into the media. TNF production was increased on stimulation of cells with Poly IC for TLR3 (334% ±60 P=0.0002, n=12) and R-848 for TLR7/8 (515% ±76 P<00001, n=l l), but lmiquimod, a TLR 7 ligand and CpG a TLR9 ligand (see Figure 5, Graph C) were unable to stimulate further release of cytokines over the spontaneous levels. This demonstrates that TLR 3 and 8 are both functional in rheumatoid synovial membrane cultures.

In summary, these results shows that TLRs 3, 7, 8 and 9 are expressed in rheumatoid membrane synovial cells but only TLRs 3 and 8 functionally induce increased TNF production in rheumatoid membrane synovial cells

Example 6

We have shown that mianseπne hydrochloπde and promazine hydrochloπde both suppress TNF production from human rheumatoid synovial membrane cultures, and show inhibition of some of the TLRs TLR3, 7, 8 and 9 are classically viewed as having an endosomal localization. Chloroquine has been reported to inhibit the function of TLR3, 7, 8 and 9, as it increases the pH inside vesicles, which is essential for functional signaling from TLR3, 7, 8 and 9 To confirm that inhibition of cytokine release from RA cultures by mianseπne hydrochloπde and promazine hydrochlonde may be through their ability to inhibit signaling through endosomal TLRs, we also measured cytokine release in cells incubated with chloroquine. There was a dose dependant effect of chloroquine with the best inhibition being observed at lOOμM, both TNF and IL-I release were inhibited (Figure 6)

Thus, chloroquine inhibits spontaneous TNF and IL-I release from rheumatoid synovial membrane cultures. Example 7

Primary human macrophages were incubated with 5μg/ml of GBR12909, 5μg/ml of clotrimazole, 5μg/ml of Propidium iodide (PI), 30μg/ml mianserine hydrochloride and 30μg/ml promazine hydrochloride for 30 minutes and then stimulated for 6 hours with the TLR4 ligand LPS (Figure 7A), with R848 a TLR7/8 ligand (Figure 7, Graph B), or with poly IC a TLR3 ligand (Figure 7C). Supernatants were collected and measured for TNF or IP-10. None of the drugs tested were able to inhibit LPS induced TNF (Figure 7, Graph A), only the serotonin receptor antagonists (mianserine hydrochloride and promazine hydrochloride) were able to suppress R-848 induced TNF production (Figure 7, Graph B). All the drugs were able to inhibit IP-10 production induced by Poly IC (Figure 7, Graph C).

The culture of rheumatoid arthritis membrane cells was as described above for Example 1. In the experiment, rheumatoid arthritis synovial membrane cells were cultured for 24 hours in the presence of media alone or media containing 5μg/ml of GBR 12909, 5μg/ml of clotrimazole, 5μg/ml of Propidium iodide (PI) and 50μg/ml mianserine hydrochloride. Supernatants were harvested and levels of the cytokine TNF were measured by ELISA. Addition of GBR 12909, clotrimazole, Propidium iodide at the time of culture did not lead to a significant decrease in the levels of TNF (Figure 7, Graph D). Mianserine hydrochloride was used as a positive control and was able to decrease the TNF levels in these cultures.

Example 8

RA synovial membrane cultures were incubated with either 20μg/ml ondansetron, 5μg/ml ritanserin, lOμg/ml metergoline, 20μg/ml loxapine, 5μg/ml methiothepin or 30μg/ml mianserine hydrochloride for 24 hours (Figure 8). Ondansetron, metergoline, loxapine, ritanserin and methiothepin were purchased from Sigma (USA). TNF production was measured by ELISA. This shows that the serotonin receptor antagonists; ondansetron, metergoline, loxapine, ritanserin, methiothepin and mianserine hydrochloride are able to inhibit spontaneous TNF production from human RA synovial membrane cultures.

Example 9

Primary human macrophages were incubated with media containing 0.3, 1, 10 or 20 μg/ml R-848 with media alone or in the presence of either (A) 2.5, 5 or 10 μg/ml mianserine or (B) 5 μg/ml mianserine for 6 hours. TNF production was measured by ELISA.

This shows that mianserine hydrochloride competitively inhibits the production of TNF induced by R-848 (Figure 9). As the concentration of R-848 increases, higher concentrations of mianserine hydrochloride are required to achieve a 50 % inhibition of the control TNF production levels (see Figure 9(A)). The inhibitory effect of mianserine hydrochloride is diminished with increasing concentrations of R-848 (see Figure 9(B)).

Our studies suggest mianserine hydrochloride is a competitive inhibitor of R-848.

Example 10

(A) Primary human macrophages were incubated with media containing 5, 10 or 20μg/ml ondansetron for 30 minutes prior to stimulation with 1 μg/ml R-848 for 6 hours. TNF production was measures by ELISA. The results are illustrated in Figure 10(A).

(B) Primary human macrophages were incubated with media containing 30 μg/ml ondansetron for 30 minutes prior to stimulation with 1 μg/ml R-848 or 10ng/ml LPS for 6 hours (n=3). Data is shown as a percentage of the maximal response for R-848 or LPS and was pooled from three separate donors. The results are illustrated in Figure 10(B) * = p<0.05. Figure 10(C) illustrates inhibition of TNF from RA synovial membrane cultures incubated with 20μg/ml ondansetron for 24 hours (n=3), * = p<0 05

This shows that ondansetron inhibits the production of TNF induced by R-848 (Figure 10) and the spontaneous TNF production from human RA synovial cultures.

Example 11

Primary human macrophages were pre-incubated with 10 or lOOμM serotonin (5-HT) for 30 minute and then stimulated with lμg/ml R-848 for 6 hours (Figure 11). TNF production was measured by ELISA. Serotonin (5-HT) was purchased from Sigma

(USA)

This shows that signaling from toll-like receptors TLR8 is not inhibited by serotonin (5-HT) and that the ability of the 5-HT receptor antagonists to inhibit TNF production induced by TLR8 is not due to effects of serotonin.

Example 12

Primary human macrophages were pre-incubated with 30μg/ml ondansetron, lOμg/ml metergohne, 20μg/ml loxapine, 5μg/ml πtanseπn or 5μg/ml methiothepin for 30 minutes and then stimulated with lμg/ml R-848 for 6 hours (Figure 12) TNF production was measured by ELISA. Ondansetron, metergohne, loxapine, πtanseπn and methiothepin were purchased from Sigma (USA).

This shows that Ondansetron, metergohne, loxapine, πtanseπn and methiothepin are able to inhibit R-848 induced TNF induction.

Example 13

RA synovial membrane cultures were incubated with either media alone or media containing 5, 10 or 20μg/ml simvastatin, 20μg/ml mianseπne or as combinations of mianseπne and simvastatin for 24 hours (Figure 13). TNF production from tπphcate cultures was measured by ELISA. Simvastatin was purchased from Sigma (USA) This shows that simvastatin and mianserine are able to inhibit spontaneous TNF production from human RA synovial membrane cultures and produce an additive effect on the inhibition of TNF when incubated together.

Claims

1. A serotonin receptor antagonist for treating inflammatory arthritis or a related condition.

2. The serotonin receptor antagonist according to claim 1, wherein the serotonin receptor antagonist is mianserine, promazine, ketanserine, ondansetron, metergoline, loxapine, ritanserin or methiothepin.

3. The serotonin receptor antagonist according to claim 1 or claim 2, wherein the inflammatory arthritis is rheumatoid arthritis.

4. The serotonin receptor antagonist according to any one of claims 1 to 3, wherein the serotonin receptor antagonist is administered in combination with a further anti-inflammatory agent.

5. The serotonin receptor antagonist according to claim 4, wherein the further anti-inflammatory agent is a non-steroidal anti-inflammatory agent (NSAID), a statin, a disease modifying anti-rheumatic drug (DMARD), a biological agent, a steroid, RNAi, aptemers, an immunosuppressive agent, a salicylate and/or a microbicidal agent.

6. Use of a serotonin receptor antagonist in the manufacture of a medicament for treating inflammatory arthritis or a related condition.

7. A kit comprising a pharmaceutical composition comprising a serotonin receptor antagonist and instructions indicating that the composition is for use in treating inflammatory arthritis or a related condition.

8. The kit of claim 7, wherein the serotonin receptor antagonist is mianserine, promazine, ketanserine, ondansetron, metergoline, loxapine, ritanserin or methiothepin. 9 This lot according to claim 7 or claim 8, wherein the inflammatory arthritis is rheumatoid arthritis

10 The lot according to any one of claims 7 to 9 wherein the serotonin receptor antagonist is administered in combination with a further anti-inflammatory agent

11 The kit according to claim 10, wherein the further anti-inflammatory agent is a non-steroidal anti-inflammatory agent (NSAID), a statin, a disease modifying anti- rheumatic drug (DMARD), a biological agent, a steroid, an immunosuppressive agent, a salicylate and/or a microbicidal agent

12 A method of treating inflammatory arthritis or a related condition in a subject, comprising administration of a serotonin receptor antagonist to the subject

13 The method of claim 12, wherein the serotonin receptor antagonist is mianseπne, promazine, ketanseπne, ondansetron, metergohne, loxapine, πtanseπn or methiothepin

14 The method of claim 12 or claim 13 wherein the subject is a mammal

15 The method of claim 14, wherein the mammal is a human

16 The method of any one of claims 12 to 15, wherein the inflammatory arthritis is rheumatoid arthritis

17 The method according to any one of claims 12 to 16, wherein the serotonin receptor antagonist is administered in combination with a further anti-inflammatory agent

18 The method according to claim 17, wherein the further anti-inflammatory agent is a non-steroidal anti-inflammatory agent (NSAED), a statin, a disease modifying anti-rheumatic drug (DMARD), a biological agent, a steroid, an immunosuppressive agent, a salicylate and/or a microbicidal agent.


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