Pyridinyl imidazoles inhibit the inflammatory phase of delayed type hypersensitivity reactions without affecting T-dependent immune responses

Assessing the systemic toxicity in rabbits after sub acute exposure to ocular irritant chemicals

Eye is a highly vascularised organ. There are chances that a foreign substance can enter the systemic circulation through the eye and cause oxidative stress and evoke immune response. Here the eyes of rabbits were exposed, for a period of 7 days, to 5 known ocular irritants: Cetyl pyridinium chloride (CPC), sodium salicylate (SS), imidazole (IMI), acetaminophen (ACT) and nicotinamide (NIC). The eyes were scored according to the draize scoring. Blood collected from the treated rabbit were analyzed for haematological and biochemical parameters. After sacrifice, histological analysis of the eye and analysis of pro-inflammatory biomarkers (IL-1α, IL-1β, IL-8 and TNF-α) in the cornea using ELISA was carried out. Spleen was collected and the proliferation capacities of spleenocytes were analyzed. Liver and brain were collected and assessed for oxidative stress. The eye irritation potential of the chemicals was evident from the redness and swelling of the conjunctiva and cornea. Histopathological analysis and ELISA assay showed signs of inflammation in the eye. However, the haematological and biochemical parameters showed no change. Spleenocyte proliferations showed only slight alterations which were not significant. Also oxidative stress in the brain and liver were negligible. In conclusion, chemicals which cause ocular irritation and inflammation did not show any systemic side-effects in the present scenario.

Characterization of YM-58483/BTP2, a novel store-operated Ca2+ entry blocker, on T cell-mediated immune responses in vivo

YM-58483/BTP2 is a blocker of store-operated Ca2+ entry (SOCE), which regulates the activation of non-excitable cells such as lymphocytes. YM-58483 has been reported to inhibit cytokine production and proliferation in T cells, and to be useful as a probable medicinal candidate for treatment of bronchial asthma. The present study investigated the pharmacological profile and therapeutic potential of YM-58483 in relation to cell-mediated immune responses. In the mouse graft-versus-host disease (GVHD) model, YM-58483 (1-30 mg/kg, p.o.) and cyclosporine A (1-30 mg/kg, p.o.) inhibited donor anti-host cytotoxic T lymphocyte (CTL) activity and IFN-gamma production, and also reduced the number of donor T cells, especially donor CD8+ T cells, in the spleen. YM-58483 and cyclosporine A inhibited T cell proliferation in a one-way mixed lymphocyte reaction (MLR) with IC50 values of 330 and 12.7 nM, respectively. Additionally, YM-58483 (1-10 mg/kg, p.o.) and cyclosporine A (2, 10 mg/kg, p.o.) inhibited the sheep red blood cell (SRBC)-induced delayed type hypersensitivity (DTH) response. These results suggest that the inhibition of SOCE leads to the prevention of antigen-induced T cell responses, which participate in autoimmune diseases such as autoimmune hepatitis and rheumatoid arthritis.

Oral treatment options for degenerative joint disease--presence and future

Alleviation of pain and inhibition of inflammation are the primary goals of pharmacotherapy of osteoarthritis (OA). These therapeutic goals can almost always be accomplished by the use of analgesics and nonsteroidal anti-inflammatory drugs (NSAID). One of the main problems of NSAIDs is their gastrointestinal toxicity, for which a prophylactic medication should be considered particularly amongst risk groups. Recent studies have shown that COX-2-selective and maybe also non-selective NSAIDs increase the cardiovascular risk so that their application is getting now drastically restricted. Pharmacological results published until now suggest that a clinically relevant minor analgesic and/or anti-inflammatory effect can be attained with the use of some of the SYmptomatic Slow Acting Drugs in OA (SYSADOAs). However, no clinical studies exist, which can positively confirm prevention, slowing down or reversal of any advanced joint cartilage destruction by any individual medication. Disease modifying therapy is still in its infancy; discovery and development of novel therapeutic targets and agents are an extremely difficult task, currently challenging many pharmaceutical companies and academic institutions.

Immunomodulation by SanPharma Fungal Metabolic Products

OBJECTIVE

In the present study, a series of fungal metabolite products from SanPharma (Dohren, Germany) were tested for effects on human peripheral blood leukocytes in vitro using standard immunologic methods.

BACKGROUND

Therapeutic strategies used in German biological medicine often include treatment (oral, nasal, rectal, topical, or injection) with fungal or bacterial products, also known as "isopathic remedies," of which some are limited to metabolic products, whereas others include microbial cell lysates and cell wall fragments as well. The SanPharma products are based on metabolites, and do not contain microbial cell wall compounds.

METHODS

Activation of natural killer (NK) cells was evaluated by cell surface immunostaining using CD3, CD56, CD69, and CD25 monoclonal antibodies. Production of interferon-gamma was evaluated by enzyme-linked immunoabsorbent assay (ELISA) on supernatants collected after 5 days' culture of peripheral blood mononuclear cells (PBMC). Direct mitogenic effect was assessed using the lipophilic membrane dye PHK26 (Sigma-Aldrich, St. Louis, MO) in a fluorescence-based proliferation assay, in which fluorescence intensity is reduced upon cell divisions. Cell viability upon exposure to fungal metabolites was assessed using propidium iodide staining and flow cytometry.

RESULTS

All fungal metabolite products specifically induced the expression of the CD69 marker on human CD3-negative, CD56-positive NK cells, but not CD3-positive T cells, in vitro, as shown by the induction of the CD69 marker on up to 50% of NK cells after 18 hours' culture with metabolites. Only one of the five metabolite products, Roqueforti, induced cyclooxygenase-2 (COX-2), indicating that nuclear factor-kappaB (NFkappaB)-mediated signaling may not have been involved in the NK activation by the other four products. The Notatum product reduced baseline levels of COX-2, indicating an anti-inflammatory effect. No evidence of toxic or mitogenic effects was found.

CONCLUSIONS

The fungal metabolite products from SanPharma specifically activate human NK cells in vitro.

LASSBio-468: a new achiral thalidomide analogue which modulates TNF-alpha and NO production and inhibits endotoxic shock and arthritis in an animal model

As part of a program researching the synthesis and immunopharmacological evaluation of novel synthetic compounds, we have described the immune modulatory profile of the new achiral thalidomide analogue LASSBio-468 in the present work. This compound was planned as an N-substituted phthalimide derivate, structurally designed as a hybrid of thalidomide and aryl sulfonamides, which were previously described as tumor necrosis factor-alpha (TNF-alpha) and PDE4 inhibitors. LASSBio-468 was recently demonstrated to inhibit the TNF-alpha production induced by lipopolysaccharide (LPS), in vivo. Here, we investigated whether this compound would affect chronic inflammation processes associated with the production of this pro-inflammatory cytokine. Treatment with LASSBio-468 before a lethal dose injection of LPS in animals greatly inhibited endotoxic shock. This effect seems to be mediated by a specific down regulation of TNF-alpha and nitric oxide production, regulated mainly at the RNA level. In another model, histopathological analysis indicated that this compound also inhibited adjuvant-induced arthritis in rats. Taken together, our data demonstrated a potent anti-inflammatory effect of LASSBio-468, suggesting its use as a potential drug against chronic inflammatory diseases.

Chromatin-mediated regulation of nucleolar structure and RNA Pol I localization by TOR

The target of rapamycin (TOR) protein is a conserved regulator of ribosome biogenesis, an important process for cell growth and proliferation. However, how TOR is involved remains poorly understood. In this study, we find that rapamycin and nutrient starvation, conditions inhibiting TOR, lead to significant nucleolar size reduction in both yeast and mammalian cells. In yeast, this morphological change is accompanied by release of RNA polymerase I (Pol I) from the nucleolus and inhibition of ribosomal DNA (rDNA) transcription. We also present evidence that TOR regulates association of Rpd3-Sin3 histone deacetylase (HDAC) with rDNA chromatin, leading to site-specific deacetylation of histone H4. Moreover, histone H4 hypoacetylation mutations cause nucleolar size reduction and Pol I delocalization, while rpd3Delta and histone H4 hyperacetylation mutations block the nucleolar changes as a result of TOR inhibition. Taken together, our results suggest a chromatin-mediated mechanism by which TOR modulates nucleolar structure, RNA Pol I localization and rRNA gene expression in response to nutrient availability.

The novel JAK-3 inhibitor CP-690550 is a potent immunosuppressive agent in various murine models

JAK-3 has been shown to play a key role in cytokine signaling via gammac, e.g. IL-2, 4, 7, 9, 15, 21. The current study describes the immunosuppressive effects of CP-690550, a novel, small molecule inhibitor of JAK-3, in various murine models. In vitro, CP-690550 effectively inhibited a murine mixed lymphocyte reaction (MLR) (IC50= 91 nm). Mice chronically dosed with CP-690550 (1.5-15 mg/kg/day) demonstrated dose- and time-dependent alterations in lymphocyte subsets when examined by flow cytometry. The most dramatic change observed was a 96% reduction in splenic NK1.1 + TCRbeta- cell numbers following 21 days of treatment. Delayed-type hypersensitivity (DTH) responses in sensitized mice were reduced in a dose-dependent manner following treatment with the JAK-3 inhibitor (1.87-30 mg/kg, s.c.). Extended survival of neonatal Balb/c hearts implanted into the ear pinna of MHC mismatched C3H/HEN mice was observed with CP-690550 monotherapy (10-30 mg/kg/day), but improved upon combination with cyclosporin (10 mg/kg/day). These data support the participation of JAK-3 in various lymphocyte homeostatic functions in mature mice. Furthermore, the ability of CP-690550 to extend cardiac allograft survival in murine models suggests it may afford a new treatment for prevention of transplant rejection.

JNK and p38 MAP kinases in CD4+ and CD8+ T cells

The c-Jun aminoterminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinase signaling pathways have been associated with cell death, differentiation and proliferation. CD4+ and CD8+ T cells have different effector functions after antigen stimulation and control specific aspects of the immune response. The studies carried out in our group indicate that the role of JNK and p38 MAP kinases in CD4+ T cells is different from their role in CD8+ T cells. Moreover, these two pathways are not redundant in either T cell population. We have also shown that p38 MAP kinase regulates early stages of T cell development in the thymus. It is therefore important to consider the specific function of these kinases in each T cell population when pharmacological inhibitors of JNK and p38 MAP kinases are used for therapeutic purposes to control the immune response.

Inhibition of the p38 pathway upregulates macrophage JNK and ERK activities, and the ERK, JNK, and p38 MAP kinase pathways are reprogrammed during differentiation of the murine myeloid M1 cell line

Mitogen-activated protein (MAP) kinases have been implicated as important mediators of the inflammatory response. Here we report that c-Jun NH(2)-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 MAP kinase activities are reprogrammed during the IL-6 induced macrophage-like differentiation of the murine myeloid M1 cell line. Moreover, p38 inhibition upregulates JNK and ERK activity in M1 cells and in thioglycollate-elicited peritoneal exudate macrophages. IL-6-induced M1 differentiation also induces expression of the anti-inflammatory cytokine IL-10, and p38 inhibition potentiates this increase in IL-10 expression in an ERK-dependent manner. Thus, we speculate that during inflammatory conditions in vivo macrophage p38 may regulate JNK and ERK activity and inhibit IL-10 expression. These data highlight the importance of p38 in the molecular mechanisms of macrophage function.

Selective suppression of neutrophil accumulation in ongoing pulmonary inflammation by systemic inhibition of p38 mitogen-activated protein kinase

The p38 mitogen-activated protein kinase (MAPK) signaling pathway regulates a wide range of inflammatory responses in many different cells. Inhibition of p38 MAPK before exposing a cell to stress stimuli has profound anti-inflammatory effects, but little is known about the effects of p38 MAPK inhibition on ongoing inflammatory responses. LPS-induced activation of p38 MAPK in human neutrophils was inhibited by poststimulation exposure to a p38 MAPK inhibitor (M39). Release of TNF-alpha, macrophage-inflammatory protein (MIP)-2 (MIP-1beta), and IL-8 by LPS-stimulated neutrophils was also reduced by poststimulation p38 MAPK inhibition. In contrast, release of monocyte chemoattractant protein-1 was found to be p38 MAPK independent. Ongoing chemotaxis toward IL-8 was eliminated by p38 MAPK inhibition, although the rate of nondirectional movement was not reduced. A murine model of acute LPS-induced lung inflammation was used to study the effect of p38 MAPK inhibition in ongoing pulmonary inflammation. Initial pulmonary cell responses occur within 4 h of stimulation in this model, so M39 was administered 4 h or 12 h after exposure of the animals to aerosolized LPS to avoid inhibition of cytokine release. Quantities of TNF-alpha, MIP-2, KC, or monocyte chemoattractant protein-1 recovered from bronchial alveolar lavage or serum were not changed. Recruitment of neutrophils, but not other leukocytes, to the airspaces was significantly reduced. Together, these data demonstrate the selective reduction of LPS-induced neutrophil recruitment to the airspaces, independent of suppression of other inflammatory responses. These findings support the feasibility of p38 MAPK inhibition as a selective intervention to reduce neutrophilic inflammation.

Differential effects of SB 242235, a selective p38 mitogen-activated protein kinase inhibitor, on IL-1 treated bovine and human cartilage/chondrocyte cultures

The p38 MAP kinase inhibitor, SB 242235, was evaluated for its effects on the metabolism of bovine and human cartilage and primary chondrocyte cultures. SB 242235 had no effect on proteoglycan synthesis (PG) in bovine articular cartilage explants (BAC), as measured by [(35)S]-sulfate incorporation into glycosaminoglycans (GAGs). In addition, the compound had no effect on IL-1 alpha-induced GAG release from these cultures. However, there was a potent, dose-dependent inhibition of nitric oxide (NO) release from IL-1 alpha-stimulated BAC with an IC(50)of approximately 0.6 microM, with similar effects observed in primary chondrocytes. The effect on BAC was time dependent, and mechanistically did not appear to be the result of inhibition of protein kinase C (PKC), protein kinase A (PKA) or MEK-1. The effect on NO release in bovine chondrocytes was at the level of inducible nitric oxide synthase (iNOS) gene expression, which was inhibited at similar concentrations as nitrite production. In primary human chondrocytes, IL-1 beta induction of p38 MAP kinase was inhibited by SB 242235 with an IC(50)of approximately 1 microM. Surprisingly, however, treatment of IL-beta-stimulated human cartilage or chondrocytes with SB 242235 did not inhibit either NO production or the induction of iNOS. On the other hand, the natural product hymenialdisine (HYM), a protein tyrosine kinase (PTK) inhibitor, inhibited NO production and iNOS in both species. In contrast to the differential control of iNOS, PGE(2)was inhibited by SB 242235 in both IL-1-stimulated bovine and human chondrocyte cultures. These studies indicate that there are species differences in the control of iNOS by p38 inhibitors and also that different pathways may control IL-1-induced proteoglycan breakdown and NO production.

The JNK and P38 MAP kinase signaling pathways in T cell-mediated immune responses

The mitogen-activated protein (MAP) kinase family members, which include the extracellular response kinases (ERK), p38, and c-Jun amino terminal kinases (JNK), play a role in mediating signals triggered by cytokines, growth factors, and environmental stress. JNK and p38 MAP kinases have been involved in inflammatory processes induced by a variety of stimuli, such as oxidative stress. Here, we describe the role of the JNK and p38 MAP kinase signaling pathways in the development of T cells in the thymus, and activation and differentiation of T cells in the peripheral immune system.

Role of p38 mitogen-activated protein kinase in a murine model of pulmonary inflammation

Early inflammatory events include cytokine release, activation, and rapid accumulation of neutrophils, with subsequent recruitment of mononuclear cells. The p38 mitogen-activated protein kinase (MAPK) intracellular signaling pathway plays a central role in regulating a wide range of inflammatory responses in many different cells. A murine model of mild LPS-induced lung inflammation was developed to investigate the role of the p38 MAPK pathway in the initiation of pulmonary inflammation. A novel p38 MAPK inhibitor, M39, was used to determine the functional consequences of p38 MAPK activation. In vitro exposure to M39 inhibited p38 MAPK activity in LPS-stimulated murine and human neutrophils and macrophages, blocked TNF-alpha and macrophage inflammatory protein-2 (MIP-2) release, and eliminated migration of murine neutrophils toward the chemokines MIP-2 and KC. In contrast, alveolar macrophages required a 1000-fold greater concentration of M39 to block release of TNF-alpha and MIP-2. Systemic inhibition of p38 MAPK resulted in significant decreases in the release of TNF-alpha and neutrophil accumulation in the airspaces following intratracheal administration of LPS. Recovery of MIP-2 and KC from the airspaces was not affected by inhibition of p38 MAPK, and accumulation of mononuclear cells was not significantly reduced. When KC was instilled as a proinflammatory stimulus, neutrophil accumulation was significantly decreased by p38 MAPK inhibition independent of TNF-alpha or LPS. Together, these results demonstrate a much greater dependence on the p38 MAPK cascade in the neutrophil when compared with other leukocytes, and suggest a means of selectively studying and potentially modulating early inflammation in the lung.

Disease-modifying activity of SB 242235, a selective inhibitor of p38 mitogen-activated protein kinase, in rat adjuvant-induced arthritis

OBJECTIVE

To evaluate the effects of SB 242235, a potent and selective inhibitor of p38 mitogen-activated protein (MAP) kinase, on joint integrity in rats with adjuvant-induced arthritis (AIA).

METHODS

Male Lewis rats with AIA were orally treated either prophylactically (days 0-20) or therapeutically (days 10-20) with SB 242235. Efficacy was determined by measurements of paw inflammation, dual-energy x-ray absorptiometry for bone-mineral density (BMD), magnetic resonance imaging (MRI), microcomputed tomography (CT), and histologic evaluation. Serum tumor necrosis factor alpha (TNFalpha) in normal (non-AIA) rats and serum interleukin-6 (IL-6) levels in rats with AIA were measured as markers of the antiinflammatory effects of the compound.

RESULTS

SB 242235 inhibited lipopolysaccharide-stimulated serum levels of TNFalpha in normal rats, with a median effective dose of 3.99 mg/kg. When SB 242235 was administered to AIA rats prophylactically on days 0-20, it inhibited paw edema at 30 mg/kg and 10 mg/kg per day by 56% and 33%, respectively. Therapeutic administration on days 10-20 was also effective, and inhibition of paw edema was observed at 60, 30, and 10 mg/kg (73%, 51%, and 19%, respectively). Significant improvement in joint integrity was demonstrated by showing normalization of BMD and also by MRI and micro-CT analysis. Protection of bone, cartilage, and soft tissues was also shown histologically. Serum IL-6 levels were decreased in AIA rats treated with the 60 mg/kg dose of compound.

CONCLUSION

Symptoms of AIA in rats were significantly reduced by both prophylactic and therapeutic treatment with the p38 MAP kinase inhibitor, SB 242235. Results from measurements of paw inflammation, assessment of BMD, MRI, and micro-CT indicate that this compound exerts a protective effect on joint integrity, and thus appears to have disease-modifying properties.

Interferon-gamma expression by Th1 effector T cells mediated by the p38 MAP kinase signaling pathway

Signal transduction via MAP kinase pathways plays a key role in a variety of cellular responses, including growth factor-induced proliferation, differentiation and cell death. In mammalian cells, p38 MAP kinase can be activated by multiple stimuli, such as pro-inflammatory cytokines and environmental stress. Although p38 MAP kinase is implicated in the control of inflammatory responses, the molecular mechanisms remain unclear. Upon activation, CD4+ T cells differentiate into Th2 cells, which potentiate the humoral immune response or pro-inflammatory Th1 cells. Here, we show that pyridinyl imidazole compounds (specific inhibitors of p38 MAP kinase) block the production of interferon-gamma (IFNgamma) by Th1 cells without affecting IL-4 production by Th2 cells. These drugs also inhibit transcription driven by the IFNgamma promoter. In transgenic mice, inhibition of the p38 MAP kinase pathway by the expression of dominant-negative p38 MAP kinase results in selective impairment of Th1 responses. In contrast, activation of the p38 MAP kinase pathway by the expression of constitutivelyactivated MAP kinase kinase 6 in transgenic mice caused increased production of IFNgamma during the differentiation and activation of Th1 cells. Together, these data demonstrate that the p38 MAP kinase is relevant for Th1 cells, not Th2 cells, and that inhibition of p38 MAP kinase represents a possible site of therapeutic intervention in diseases where a predominant Th1 immune response leads to a pathological outcome. Moreover, our study provides an additional mechanism by which the p38 MAP kinase pathway controls inflammatory responses.