Tranilast inhibits interleukin-1beta-induced monocyte chemoattractant protein-1 expression in rat mesangial cells

In-vitro inhibition of NLRP3 inflammasome by 3,6-dihydroxyflavone (3,6-DHF): a therapeutic strategy for the treatment of chronic inflammatory and autoimmune diseases

Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome complex has an important role in immune system and its abnormal activation is associated with the pathogenesis of various inflammatory and auto-immune diseases. The study reveals the anti-inflammatory effects of 3,6-dihydroxyflavone (3,6-DHF). Here, we aimed to determine the inhibitory effects of 3,6-DHF on NLRP3 inflammasome and its associated components, thereby determining the signaling pathways involved in the inhibition. Reactive oxygen species (ROS) and nitric oxide (NO) were quantified by chemiluminescence and Griess methods, respectively. Inflammatory cell model was induced in human leukemic monocytes (THP-1). mRNA levels were estimated through real-time RT-PCR, protein expressions were evaluated by protein slot blot and immunocytochemistry, MTT and alamar blue assays were employed for toxicity studies. The compound 3,6-DHF was found to be the potent inhibitor of NLRP3 inflammasome by targeting the molecules involve in its activation pathway. Anti-inflammatory effects were revealed by inhibition of ROS and NO, reduction in the transcription of caspase-1, ASC, IL-1β and TLR-4 was observed along with the marked inhibition of NLRP3, IL-18, NF-κB and pNF-κB at translational level. 3,6-DHF was non-toxic on normal human fibroblast (BJ) and THP-1 cells and, could be a potential therapeutic agent in NLRP3 inflammasome driven diseases.

A novel mice model of acute flares in osteoarthritis elicited by intra-articular injection of cultured mast cells

PURPOSE

Mast cells are multifunctional in osteoarthritis (OA), and infiltration of activated mast cells likely contributes to disease severity and progression. However, the detailed mechanisms of action are unclear. The purpose of this study was to elucidate the role of mast cell infiltration in OA at histological level using a new mice model and to investigate pharmacological inhibitory effects of existing mast cell stabilizers in this model.

METHODS

Mice were injected intra-articularly with monosodium iodoacetate (MIA 0.5 mg) or PBS on day 0, and PBS, with or without mast cells (MC: 1 × 10⁶ cells) on day 14. They were divided into four groups: OA flare (MIA + MC), OA (MIA + PBS), MC non-OA (PBS + MC), and PBS non-OA (PBS + PBS). In OA flare, the MC stabilizer drug (tranilast: 400 mg/kg/day) or PBS was administered intraperitoneally from days 15 to 21.

RESULTS

Histologically, modified Mankin score of the OA flare was significantly higher than that of OA (7.0 [1.8] vs. 3.3 [1.3], P < 0.05), and a larger number of mast cells was observed in OA flare than in OA (34.5 [6.3]/mm² vs. 27.2 [2.3]/mm², P < 0.05) on day 22. OA flare also showed acute exacerbation of pain and increased gene expression of pro-inflammatory cytokines and aggrecanase compared with OA. Administration of tranilast to OA flare-up provoked significant improvements in term of histological changes, pain, and gene expression at day 22.

CONCLUSION

Our novel model possibly mimics OA flare conditions, which may open a new strategy of disease-modifying treatment for OA, focused on controlling the multiple functions of mast cells.

Tranilast: a potential anti-Inflammatory and NLRP3 inflammasome inhibitor drug for COVID-19

SARS-CoV-2 is a type of beta-CoV that develops acute pneumonia, which is an inflammatory condition. A cytokine storm has been recognized as one of the leading causes of death in patients with COVID-19. ALI and ARDS along with multiple organ failure have also been presented as the consequences of acute inflammation and cytokine storm. It has been previously confirmed that SARS-CoV, as another member of the beta-CoV family, activates NLRP3 inflammasome and consequently develops acute inflammation in a variety of ways through having complex interactions with the host immune system using structural and nonstructural proteins. Numerous studies conducted on Tranilast have further demonstrated that the given drug can act as an effective anti-chemotactic factor on controlling inflammation, and thus, it can possibly help the improvement of the acute form of COVID-19 by inhibiting some key inflammation-associated transcription factors such as NF-κB and impeding NLRP3 inflammasome. Several studies have comparably revealed the direct effect of this drug on the prevention of inappropriate tissue's remodeling; inhibition of neutrophils, IL-5, and eosinophils; repression of inflammatory cell infiltration into inflammation site; restriction of factors involved in acute airway inflammation like IL-33; and suppression of cytokine IL-13, which increase mucosal secretions. Therefore, Tranilast may be considered as a potential treatment for patients with the acute form of COVID-19 along with other drugs.

Tranilast abrogates cisplatin-induced testicular and epididymal injuries: An insight into its modulatory impact on apoptosis/proliferation

Cisplatin is a chemotherapeutic agent whose therapeutic use is greatly limited by the associated organs' toxicity and particularly, testicular toxicity. Cisplatin-induced testicular damage reported being mediated through mitochondria-mediated apoptosis, inflammation, and oxidative stress. Evidence showed that tranilast (TRN) has the ability to restore the oxidative status and modulate TRAIL/caspase-8 signaling. This led us to hypothesize that TRN could abrogate cisplatin-induced testicular and epididymal injuries via inhibiting oxidative stress and modulating proliferation and TRAIL/caspase-8/cJNK signaling. Cisplatin injection induced oligospermia and abnormalities in testicular and epididymal structure along with impaired oxidative status. TRN administration (100 or 300 mg/kg) for 7 days post-cisplatin injection preserved spermatogenesis and restored testicular and epididymal architecture, but restoration was more so in TRN300 than TRN100. This was in line with the restoration of balanced oxidative status as indicated by the increased total antioxidant capacity, glutathione and superoxide dismutase activity, and the decreased malondialdehyde content in testes (p < 0.05 vs. cisplatin). TRN increased the cell proliferation revealed by the increased expression of proliferating cell nuclear antigen in a dose-dependent manner (p < 0.05 vs. cisplatin) whereas only TRN300 decreased testicular cJNK, TRAIL, and caspase-8 expression (p < 0.05 vs. cisplatin). Moreover, TRN dose-dependently inhibited the pro-inflammatory transcription factor NF-kB and the cytokine TNF-α expressions in testes. In conclusion, TRN300 was more effective than TRN100 in alleviating cisplatin-induced testicular and epididymal injuries and in enhancing spermatogenesis. This curative effect of TRN might be mediated through its antioxidant and anti-inflammatory impacts along with its modulatory impact on cJNK/TRAIL/caspase-8 signaling favoring proliferation rather than apoptosis.

Klotho supplementation attenuates blood pressure and albuminuria in murine model of IgA nephropathy

BACKGROUND

Klotho interacts with various membrane proteins, such as transforming growth factor-β (TGFβ) and insulin-like growth factor (IGF) receptors. The renal expression of klotho is diminished in chronic kidney disease.

METHOD

In this study, we assessed the effects of klotho supplementation on a murine model of IgA nephropathy. Twenty-four-week-old hyper serum IgA (HIGA) mice were subcutaneously injected daily with recombinant human klotho protein (20 μg/kg per day) or the vehicle. After 2 months, the mice were killed using an anesthesia overdose and their kidneys were harvested for analysis.

RESULTS

Supplementation of exogenous klotho protein reduced SBP, albuminuria, 8-epi-prostaglandin F2α excretion, glomerular filtration rate, renal angiotensin II concentration, and angiotensinogen expression in HIGA mice. Additionally, it enhanced renal expression of superoxide dismutase (SOD) and renal klotho itself. The findings using laser-manipulated microdissection demonstrated that klotho supplementation reduced the glomerular expression of TGFβ, fibronectin, and IGF, and increased the glomerular expression of connexin (Cx) 40.

CONCLUSION

These results indicate that klotho supplementation reduces blood pressure by suppressing the renin--angiotensin system in HIGA mice. Klotho inhibits IGF signaling to preserve glomerular Cx40 levels, ameliorating albuminuria in HIGA mice. Klotho protein supplementation attenuates mesangial expansion by inhibiting TGFβ signaling in HIGA mice.

Tranilast induces MiR-200c expression through blockade of RelA/p65 activity in leiomyoma smooth muscle cells

OBJECTIVE

To determine the mechanism by which tranilast induces miR-200c expression in leiomyoma smooth muscle cells (LSMCs).

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Blockade of RelA/p65.

MAIN OUTCOME MEASURE(S)

Effects of tranilast and blockade of RelA/p65 on miR-200c expression.

RESULT(S)

Tranilast, an inflammation inhibitor, dose-dependently induced miR-200c in LSMCs and myometrium smooth muscle cells (MSMCs), with a more profound effect in LSMCs than in MSMCs. The treatment of LSMCs with Bay 117082, an inhibitor of IκB phosphorylation, further enhanced miR-200c induction by tranilast. The knockdown of RelA/p65 by small interfering RNA also induced miR-200c expression in LSMCs. Although tranilast had no effect on total RelA/p65 protein levels in LSMCs, it significantly induced RelA/p65 phosphorylation at S536 while reducing its activity as well as its nuclear translocation. ChIP assay indicated that tranilast reduces the binding ability of RelA/p65 to miR-200c promoter, resulting in miR-200c induction. Tranilast also inhibited interleukin-8 (IL8) expression in LSMCs. The induction of miR-200c by tranilast partially mediates the inhibitory effect of tranilast on the expression of IL8 and cyclin-dependent kinase 2 in LSMCs.

CONCLUSION(S)

Induction of miR-200c by tranilast in LSMCs is mediated through a transcriptional mechanism involving inhibition of the nuclear factor κB signaling pathway. These results highlight the significance of inflammation in the pathogenesis of leiomyoma and the potential utility of antiinflammatory drugs for treatment of leiomyomas.

Preventive Effect of Synthetic Tryptophan Metabolite on Silicone Breast Implant-Induced Capsule Formation

BACKGROUND

In the field of plastic surgery, capsular contracture after silicone breast implant surgery is a major clinical problem. This experimental study confirms that the synthetic tryptophan metabolite N-(3',4'-dimethoxycinnamonyl) anthranilic acid (Tranilast) reduces capsule formation and prevents capsular contracture.

METHODS

Eighteen New Zealand white rabbits were divided into 2 groups. In the experimental group, implants were inserted into each rabbit, and oral synthetic tryptophan metabolite was administered daily at a dose of 5 mg/kg in 10 mL of saline. In the control group, rabbits received implants and the same amount of saline without the metabolite. After 2 months, peri-implant tissues were harvested and analyzed.

RESULTS

The thickness of the capsules and the inflammatory cell counts were decreased in the experimental group (P < 0.001). The collagen fibers in the experimental group were thinner, less dense, and more organized than in control group. The results of reverse transcription quantitative polymerase chain reaction analysis showed that the genes for transforming growth factor β1 (P = 0.002), alpha smooth muscle actin (P < 0.001), and collagen types I (P = 0.002) and III (P = 0.004) were underexpressed in the experimental groups. Furthermore, the counts of T-cell immunity-related cytokine presenting cells were decreased in the experimental groups (CD3, 4, 25, 45RA, 45RO, 69, interleukin-2, 4 [P < 0.001], and interferon γ [P = 0.028]).

CONCLUSIONS

This study confirms that a synthetic derivative of a tryptophan metabolite decreases capsule formation and prevents capsular contracture by inhibiting the differentiation of fibroblasts to myofibroblasts, selectively inhibiting collagen synthesis, and decreasing specific T-cell immune responses by changing anti-inflammatory cytokine expression.

Tranilast directly targets NLRP3 to treat inflammasome-driven diseases

The dysregulation of NLRP3 inflammasome can cause uncontrolled inflammation and drive the development of a wide variety of human diseases, but the medications targeting NLRP3 inflammasome are not available in clinic. Here, we show that tranilast (TR), an old anti‐allergic clinical drug, is a direct NLRP3 inhibitor. TR inhibits NLRP3 inflammasome activation in macrophages, but has no effects on AIM2 or NLRC4 inflammasome activation. Mechanismly, TR directly binds to the NACHT domain of NLRP3 and suppresses the assembly of NLRP3 inflammasome by blocking NLRP3 oligomerization. In vivo experiments show that TR has remarkable preventive or therapeutic effects on the mouse models of NLRP3 inflammasome‐related human diseases, including gouty arthritis, cryopyrin‐associated autoinflammatory syndromes, and type 2 diabetes. Furthermore, TR is active ex vivo for synovial fluid mononuclear cells from patients with gout. Thus, our study identifies the old drug TR as a direct NLRP3 inhibitor and provides a potentially practical pharmacological approach for treating NLRP3‐driven diseases.

Current Approaches Including Novel Nano/Microtechniques to Reduce Silicone Implant-Induced Contracture with Adverse Immune Responses

Capsular contracture, which is the pathologic development of fibrous capsules around implants, is a major complication of reconstructive and aesthetic breast surgeries. Capsular contracture can cause implant failure with breast hardening, deformity, and severe pain. The exact mechanisms underlying this complication remain unclear. In addition, anaplastic large cell lymphoma is now widely recognized as a very rare disease associated with breast implants. Foreign body reactions are an inevitable common denominator of capsular contracture. A number of studies have focused on the associated immune responses and their regulation. The present article provides an overview of the currently available techniques, including novel nano/microtechniques, to reduce silicone implant-induced contracture and associated foreign body responses.

Inhibitory Effects of Tranilast on Cytokine, Chemokine, Adhesion Molecule, and Matrix Metalloproteinase Expression in Human Corneal Fibroblasts Exposed to Poly(I:C)

Purpose/Aim: Viral infection of the cornea can result in inflammation and scarring and eventually cause blindness. Polyinosinic-polycytidylic acid [poly(I:C)], an analog of viral double-stranded RNA, induces the synthesis of various cytokines, chemokines, adhesion molecules, and matrix metalloproteinases (MMPs) in corneal fibroblasts. The effects of tranilast on the expression of these molecules in human corneal fibroblasts were examined.

MATERIALS AND METHODS

Human corneal fibroblasts were cultured with or without poly(I:C) or tranilast. The release of the proinflammatory cytokine interleukin (IL)-6 and of the chemokines IL-8 and monocyte chemotactic protein-1 (MCP-1) was measured with enzyme-linked immunosorbent assays. The expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), MMP-1, and MMP-3 was evaluated by immunoblot or immunofluorescence analysis. The phosphorylation of mitogen-activated protein kinases (MAPKs), c-Jun (a component of the transcription factor AP-1), and IκB-α (an endogenous inhibitor of the transcription factor NF-κB) was examined by immunoblot analysis.

RESULTS

Tranilast inhibited in a concentration- and time-dependent manner the production of IL-6, IL-8, MCP-1, ICAM-1, VCAM-1, MMP-1, and MMP-3 by corneal fibroblasts exposed to poly(I:C). It also inhibited the poly(I:C)-induced phosphorylation of c-Jun and the MAPK JNK without affecting that of IκB-α or the MAPKs ERK and p38.

CONCLUSIONS

Tranilast inhibited proinflammatory cytokine, chemokine, adhesion molecule, and MMP expression in human corneal fibroblasts exposed to poly(I:C), with these effects likely being mediated by attenuation of JNK-AP-1 signaling. Tranilast might therefore be expected to limit immune cell infiltration and stromal degradation associated with viral infection of the cornea.

Tranilast ameliorates cyclophosphamide-induced lung injury and nephrotoxicity

The world-wide increase in cancer incidence imposes a corresponding significant increase in the use of chemotherapeutic agents. Nephrotoxicity is a side effect frequently encountered with cyclophosphamide (CP), which is also well-known to cause acute and chronic lung toxicities. The current study focuses on the evaluation of the potential protective efficacy of tranilast against acute and subacute CP-induced lung and kidney injuries in male Swiss Albino mice. Intraperitoneal CP significantly impaired oxidant/anti-oxidant balance and increased inflammatory cell count in bronchoalveolar lavage fluid, serum creatinine, blood urea nitrogen (BUN), tumor necrosis factor-α (TNF-α) and lactate dehydrogenase (LDH) levels, with significant impairment of lung and kidney architectures. Tranilast taken orally for 8 and 14 days significantly enhanced mice anti-oxidant defense mechanisms; it increased lung and kidney SOD activity, GSH content and reduced lipid peroxidation. Tranilast significantly reduced serum creatinine and BUN. Furthermore, it decreased accumulation of inflammatory cells in the lungs. Serum TNF-α, LDH, total lung and kidney protein contents significantly declined as well. Histopathological examination revealed concomitant significant tissue recovery. Such results show a significant protective potential of tranilast against deleterious lung and kidney damage induced by CP, probably by enhancing host antioxidant defense mechanism, decreasing cytotoxicity, and decreasing expression of inflammatory cytokines.

Inhibitory Effect of Tranilast on Transforming Growth Factor-Beta-Induced Protein in Granular Corneal Dystrophy Type 2 Corneal Fibroblasts

PURPOSE

To investigate the effects of tranilast, an inhibitor of chemical mediators and fibroblast proliferation, on the expression of transforming growth factor-beta (TGF-β)-induced protein (TGFBIp) in wild-type (WT) and homozygous (HO) granular corneal dystrophy type 2 corneal fibroblasts.

METHODS

Cell proliferation and cytotoxicity were measured by Cell Counting Kit-8 and lactate dehydrogenase assay. Western blotting and real-time polymerase chain reaction were used to determine changes in the expression of TGFBIp and TGFBI mRNA. We determined the effects of tranilast on phosphorylated Smad2 (pSmad2) and pSmad3, wound-healing, and expression of alpha-smooth muscle actin (α-SMA), type I collagen, and integrins.

RESULTS

High concentrations of tranilast decreased proliferation of corneal fibroblasts but did not cause elevation of lactate dehydrogenase, except at 1.0 mM tranilast. TGF-β increased the expression of TGFBIp and TGFBI mRNA in WT and HO corneal fibroblasts. Cotreatment of corneal fibroblasts with tranilast and TGF-β reduced the levels of TGFBIp and TGFBI mRNA. In addition, application of tranilast reduced pSmad2 in WT and HO corneal fibroblasts and pSmad3 in HO corneal fibroblasts, both of which were increased initially by TGF-β. Tranilast delayed wound healing and reduced the expression of α-SMA, type I collagen, and some of integrins in WT and HO corneal fibroblasts.

CONCLUSIONS

Application of tranilast in WT and HO corneal fibroblasts inhibited the expression of TGFBIp by blocking TGF-β signaling. Thus, tranilast may be useful in delaying or preventing the recurrence of corneal opacity in TGFBI-linked corneal dystrophies if clinical studies confirm these findings.

The tryptophan derivative, tranilast, and conditioned medium with indoleamine 2,3-dioxygenase-expressing cells inhibit the proliferation of lymphoid malignancies

Indoleamine 2,3-dioxygenase (IDO) is an enzyme that catalyzes tryptophan degradation and induces immunosuppression. Although IDO is an important factor that allows tumors to escape from immunological attack, its effect on lymphoid malignancies has not been fully revealed. We evaluated the expression of IDO in samples from patients with B-cell malignancies. The IDO expression in the tumor samples was comparable to those in peripheral blood mononuclear cells from healthy donors and had mainly originated from non-B cell populations. We introduced IDO gene into Chinese hamster ovary (CHO) cells. We then cultured various cell lines using CHO- or CHO-IDO-conditioned medium. Compared with the CHO medium (CHO-CM), the CHO-IDO medium (IDO-CM) decreased the viability of lymphoid cell lines but not those of the non-lymphoid lines. Next, we examined the effects of tryptophan metabolites on lymphoid tumors, and revealed that the drug N-[3',4'-dimethoxycinnamoyl] anthranilic acid (tranilast), a synthetic derivative of the tryptophan metabolite, was able to repress proliferation and dose-dependently induce cell death of lymphoid cell lines. Tranilast induced the activation of the c-Jun N-terminal kinase, which is activated by cellular stress, in lymphoid cells. The effect of tranilast on lymphoid cells was independent of the aryl hydrocarbon receptor (AhR) although tranilast has been reported to be an AhR agonist. Finally, the administration of tranilast decreased murine lymphoid tumor progression in vivo. These results indicated that IDO and tryptophan derivatives, particularly tranilast, can be tools for the therapy for lymphoid malignancies.

Tranilast: a review of its therapeutic applications

Tranilast (N-[3',4'-dimethoxycinnamoyl]-anthranilic acid) is an analog of a tryptophan metabolite. Initially, tranilast was identified as an anti-allergic agent, and used in the treatment of inflammatory diseases, such as bronchial asthma, atypical dermatitis, allergic conjunctivitis, keloids and hypertrophic scars. Subsequently, the results showed that it could be also effective in the management of a wide range of conditions. The beneficial effects of tranilast have also been seen in a variety of disease states, such as fibrosis, proliferative disorders, cancer, cardiovascular problems, autoimmune disorders, ocular diseases, diabetes and renal diseases. Moreover, several trials have shown that it has very low adverse effects and it is generally well tolerated by patients. In this review, we have attempted to accurately summarize previously published studies relating to the use of tranilast for a range of disorders and discuss the drug's possible mode of action. The major mode of the drug's efficacy appears to be the suppression of the expression and/or action of the TGF-β pathway, but the drug affects other factors as well. The findings presented in this review demonstrate the potential of tranilast for the control of a vast array of pathological situations, furthermore, it is a prescribed drug without severe side effects.

Protection against ovariectomy-induced bone loss by tranilast

Background

Tranilast (N-(3′,4′-dimethoxycinnamonyl) anthranilic acid) has been shown to be therapeutically effective, exerting anti-inflammatory and anti-oxidative effects via acting on macrophage. We hypothesized that Tranilast may protect against oxidative stress-induced bone loss via action in osteoclasts (OCs) that shares precursors with macrophage.

Methodology and Principal Findings

To elucidate the role of Tranilast, ovariectomy (OVX)-induced bone loss in vivo and OC differentiation in vitro were evaluated by µCT and tartrate-resistant acid phosphatase staining, respectively. Oral administration of Tranilast protected against OVX-induced bone loss with decreased serum level of reactive oxygen species (ROS) in mice. Tranilast inhibited OC formation in vitro. Decreased osteoclastogenesis by Tranilast was due to a defect of receptor activator of nuclear factor-κB ligand (RANKL) signaling, at least partly via decreased activation of nuclear factor-κB and reduced induction and nuclear translocation of nuclear factor of activated T cells, cytoplasmic 1 (or NFAT2). Tranilast also decreased RANKL-induced a long lasting ROS level as well as TGF-β to inhibit osteoclastogenesis. Reduced ROS caused by Tranilast was due to the induction of ROS scavenging enzymes (peroxiredoxin 1, heme oxygenase-1, and glutathione peroxidase 1) as well as impaired ROS generation.

Conclusions/Significance

Our data suggests the therapeutic potential of Tranilast for amelioration of bone loss and oxidative stress due to loss of ovarian function.

PAR2-induced inflammatory responses in human kidney tubular epithelial cells

Protease-activated receptor-2 (PAR2) is a G protein-coupled receptor abundantly expressed in the kidney. The aim of this study was to profile inflammatory gene and protein expression induced by PAR2 activation in human kidney tubular epithelial cells (HTEC). A novel PAR2 antagonist, GB88, was used to confirm agonist specificity. Intracellular Ca(2+) (iCa(2+)) mobilization, confocal microscopy, gene expression profiling, qRTPCR, and protein expression were used to characterize PAR2 activation. PAR2 induced a pronounced increase in iCa(2+) concentration that was blocked by the PAR2 antagonist. Treatment with SLIGKV-NH2 at the apical or basolateral cell surface for 5 h induced expression of a range of inflammatory genes by greater than fourfold, including IL-1β, TRAF1, IL-6, and MMP-1, as assessed by cDNA microarray and qRTPCR analysis. Using antibody arrays, GM-CSF, ICAM-1, TNF-α, MMP-1, and MMP-10 were among the induced proteins secreted. Cytokine-specific ELISAs identified three- to sixfold increases in GM-CSF, IL-6, IL-8, and TNF-α, which were blocked by GB88 and protein kinase C inhibitors. Treatment of cells at the basolateral surface induced more potent inflammatory responses, with release of MCP-1 and fibronectin to the apical and basolateral compartments; apical treatment only increased secretion of these factors to the apical compartment. PAR2 activation at the basolateral surface dramatically reduced transepithelial electrical resistance (TEER) whereas apical treatment had no effect. There was very little leakage (<5%) of peptides across the cell monolayer (liquid chromatography-mass spectrometry). In summary, SLIGKV-NH2 induced robust proinflammatory responses in HTEC that were antagonized by GB88. These results suggest that PAR2 antagonists could be useful disease-modifying, anti-inflammatory agents in kidney disease.

Tranilast ameliorates impaired hepatic functions in Schistosoma mansoni-infected mice

The ability of tranilast, a mast cell stabilizer and anti-transforming growth factor(β) (TGF(β)) to improve impaired hepatic functions in Schistosoma mansoni (S. mansoni)-infected mice, was investigated, providing the first evidence on the ability of tranilast to improve hepatic impairment due to schistosomal infection. Tranilast had significant beneficial effects against progression of hepatic fibrosis in S. mansoni-infected mice treated with praziquantel and those untreated. Different aspects of drug activity were investigated. Its effect on serum liver functions was evaluated by estimating: alanine aminotransferase, aspartate aminotransferase, total bilirubin, alkaline phosphatase and albumin. Its effect on the extent of liver fibrosis, through estimation of hepatic hydroxyproline and hepatic collagen content in liver hydrolysates, was also evaluated. Also, the expression of profibrogenic mediators, such as serum TGF(β1), was estimated. Finally, the effect on S. mansoni infection itself was studied, via histopathological examination of liver specimens stained with both hematoxylin-eosin and Masson's trichome stains. Tranilast ameliorated the harmful effects of S. mansoni infection on the liver. Such action was manifested in its significant ability to improve impaired hepatic functions, reduce histopathological changes, lower hepatic collagen content and finally reduce serum TGF(β1) levels. The beneficial effect of tranilast may be in part due to its ability to reduce the production of profibrogenic mediators in the infected animals by improving the host immune response or by interfering with critical steps in the fibrogenic cascade.

A dual-inhibition study on vascular smooth muscle cells with meclofenamic acid and β-irradiation for the prevention of restenosis

PURPOSE

Restenosis is still one of the major limitations after angioplasty. A therapeutic treatment combining β-irradiation and pharmacologic cyclooxygenase-2 inhibition was employed to study the impact on vascular smooth muscle cells (SMCs).

MATERIALS AND METHODS

The effects of meclofenamic acid in combination with yttrium-90 ((90)Y) on cell growth, clonogenic activity, cell migration, and cell cycle distribution of human aortic SMCs were investigated. Treatment was sustained over a period of 4 days and recovery of cells was determined until day 20 after initiation. The hypothesis was that there is no difference between control and treated groups.

RESULTS

A dose-dependent growth inhibition was observed in single and combined treatment groups for meclofenamic acid and β-irradiation. Cumulative radiation dosage of 8 Gy completely inhibited colony formation. This was also observed for 200 μM meclofenamic acid alone or in combination with minor β-irradiation dosages. Results of the migration tests showed also a dose dependency with additive effects of combined therapy. Meclofenamic acid 200 μM alone and with cumulative β-irradiation dosages resulted in an increased G2/M-phase share.

CONCLUSIONS

Incubating human SMCs with meclofenamic acid and (90)Y for a period of 4 d (ie, 1.5 half-life times) resulted in an effective inhibition of smooth muscle cell proliferation, colony formation, and migration.

Tranilast attenuates the up-regulation of thioredoxin-interacting protein and oxidative stress in an experimental model of diabetic nephropathy

BACKGROUND

Diabetic nephropathy is the leading cause of kidney failure in the developed world. Tranilast has been reported to not only act as an anti-inflammatory and anti-fibrotic compound, but it also exerts anti-oxidative stress effects in diabetic nephropathy. Thioredoxin-interacting protein (Txnip) is the endogenous inhibitor of the anti-oxidant thioredoxin and is highly up-regulated in diabetic nephropathy, leading to oxidative stress and fibrosis. In this study, we aimed to investigate whether tranilast exerts its anti-oxidant properties through the inhibition of Txnip.

METHODS

Heterozygous Ren-2 rats were rendered diabetic with streptozotocin. Another group of rats were injected with citrate buffer alone and treated as non-diabetic controls. After 6 weeks of diabetes, diabetic rats were divided into two groups: one group gavaged with tranilast at 200 mg/kg/day and another group with vehicle.

RESULTS

Diabetic rats had a significant increase in albuminuria, tubulointerstitial fibrosis, peritubular collagen IV accumulation, reactive oxygen species (ROS) and macrophage infiltration (all P < 0.05). These changes were associated with an increase in Txnip mRNA and protein expression in the tubules and glomeruli of diabetic kidney. Treatment with tranilast for 4 weeks significantly attenuated Txnip up-regulation in diabetic rats and this was associated with a reduction in ROS, fibrosis and macrophage infiltration (all P < 0.05).

CONCLUSIONS

This is the first study to demonstrate that tranilast not only has anti-inflammatory and anti-fibrotic effects as previously reported but also attenuates the up-regulation of Txnip and oxidative stress in diabetic nephropathy.

Expanded network of inflammatory markers of atherogenesis: where are we now?

Inflammatory biomarkers play a pivotal role in atherosclerotic lesions. The plasma levels of these markers are predictive of adverse outcomes such as myocardial infarction and cardiovascular death. The immune system is involved at all stages of atherogenesis via activation of monocytes/macrophages and T lymphocytes. Circulating proinflammatory cytokines and chemokines produced by these cells interact with specific receptors on various cells and activate specific signaling pathways, leading to inflammation-induced atherosclerotic lesions. Recent studies have focused on predictive value of inflammatory biomarkers such as C-reactive protein and interleukin-6. These biomarkers were shown to be associated with poor quality of life and predictive of adverse events in coronary atherosclerosis and left ventricular dysfunction. Vascular predictive value of other numerous inflammatory markers is being investigated. We herein analyze the role of several mediators of inflammation, affecting vascular functions and leading toward atherosclerotic lesions.

Expanded Network of Inflammatory Markers of Atherogenesis: Where Are We Now?

Inflammatory biomarkers play a pivotal role in atherosclerotic lesions. The plasma levels of these markers are predictive of adverse outcomes such as myocardial infarction and cardiovascular death. The immune system is involved at all stages of atherogenesisviaactivation of monocytes/macrophages and T lymphocytes.Circulating proinflammatory cytokines and chemokines produced by these cells interact with specific receptors on various cells and activate specific signaling pathways, leading to inflammation-induced atherosclerotic lesions. Recent studies have focused on predictive value of inflammatory biomarkers such as C-reactive protein and interleukin-6. These biomarkers were shown to be associated with poor quality of life and predictive of adverse events in coronary atherosclerosis and left ventricular dysfunction. Vascular predictive value of other numerous inflammatory markers is being investigated. We herein analyze the role of several mediators of inflammation, affecting vascular functions and leading toward atherosclerotic lesions.

Effect of tranilast on matrix metalloproteinase production from neutrophils in-vitro

Tranilast is an anti-allergic agent that blocks the release of chemical mediators, such as histamine and leukotrienes from mast cells, and has been reported to suppress keloid and hypertrophic scar formation. Since matrix metalloproteinases (MMPs) play an essential role in tissue remodelling, this study was undertaken to determine whether tranilast suppresses MMP production from neutrophils after lipopolysaccharide (LPS) stimulation in-vitro. Neutrophils from five healthy donors (1times105 cells/mL) were stimulated with 1.0 μg mL−1 LPS in the presence or absence of various concentrations of tranilast for 24 h. MMP-7, MMP-8, MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 levels in the culture supernatants were assayed by ELISA. In addition, the influence of tranilast on MMP mRNA expression and transcriptional factor activation in cells cultured for 12 h and 4 h was also evaluated by reverse transcriptase—polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Tranilast inhibited MMP and TIMP-1 production from neutrophils when cells were treated with the agent at more than 5.0times10−5  m. It also suppressed MMP mRNA expression and transcriptional factor activation induced in neutrophils by LPS stimulation. The results suggest that tranilast inhibits the formation of keloid scarring through the suppression of factors such as MMPs and TIMP, which are essential for tissue remodelling, from inflammatory cells.

The anti-allergic compound tranilast attenuates inflammation and inhibits bone destruction in collagen-induced arthritis in mice

BACKGROUND AND PURPOSE

Recent findings suggest the importance of mast cells in the pathogenesis of rheumatoid arthritis and their potential as a therapeutic target. Tranilast is an anti-allergic compound with a potent membrane-stabilizing effect on mast cells and a wide range of anti-inflammatory effects, thus may be advantageous in the treatment of arthritis. Here, we have evaluated the effects of tranilast on the progression of collagen-induced arthritis in mice.

EXPERIMENTAL APPROACH

Tranilast (400 mg.kg(-1).day(-1)) was orally administered for 8 weeks to mice with established collagen-induced arthritis. Arthritis was assessed by clinical signs and X-ray scores. In paw tissue, the numbers of mast cells and osteoclasts were measured by histological analysis, and several inflammatory factors were assessed by RT-PCR and Western blot analysis.*

KEY RESULTS

TNF-alpha-positive mast cells were present extensively throughout the inflamed synovium of vehicle-treated arthritic mice, with some mast cells in close proximity to osteoclasts in areas of marked bone and cartilage destruction. Tranilast significantly reduced clinical and X-ray scores of arthritis and decreased numbers of TNF-alpha-positive mast cells and mRNA levels of TNF-alpha, chymase (mouse mast cell protease 4), tryptase (mouse mast cell protease 6), stem cell factor, interleukin-6, cathepsin-K, receptor activator of nuclear factor-kappaB, and of receptor activator of nuclear factor-kappaB-ligand, but increased interleukin-10 mRNA level in paws of arthritic mice. Osteoclast numbers were decreased by treatment with tranilast.

CONCLUSIONS AND IMPLICATIONS

Tranilast possesses significant anti-rheumatic efficacy and, probably, this therapeutic effect is partly mediated by inhibition of mast cell activation and osteoclastogenesis.

Pathobiology of transforming growth factor beta in cancer, fibrosis and immunologic disease, and therapeutic considerations

Transforming growth factor beta (TGF-beta) is a highly pleiotropic cytokine that plays an important role in wound healing, angiogenesis, immunoregulation and cancer. The cells of the immune system produce the TGF-beta1 isoform, which exerts powerful anti-inflammatory functions, and is a master regulator of the immune response. However, this is context dependent, because TGF-beta can contribute to the differentiation of both regulatory (suppressive) T cells (Tr cells) and inflammatory Th17 cells. While TGF-beta might be underproduced in some autoimmune diseases, it is overproduced in many pathological conditions. This includes pulmonary fibrosis, glomerulosclerosis, renal interstitial fibrosis, cirrhosis, Crohn's disease, cardiomyopathy, scleroderma and chronic graft-vs-host disease. In neoplastic disease, TGF-beta suppresses the progression of early lesions, but later this effect is lost and cancer cells produce TGF-beta, which then promotes metastasis. This cytokine also contributes to the formation of the tumor stroma, angiogenesis and immunosuppression. In view of this, several approaches are being studied to inhibit TGF-beta activity, including neutralizing antibodies, soluble receptors, receptor kinase antagonist drugs, antisense reagents and a number of less specific drugs such as angiotensin II antagonists and tranilast. It might be assumed that TGF-beta blockade would result in severe inflammatory disease, but this has not been the case, presumably because the neutralization is only partial. In contrast, the systemic administration of TGF-beta for therapeutic purposes is limited by toxicity and safety concerns, but local administration appears feasible, especially to promote wound healing. Immunotherapy or vaccination stimulating TGF-beta production and/or Tr differentiation might be applied to the treatment of autoimmune diseases. The benefits of new therapies targeting TGF-beta are under intense investigation.

Reduction of post-surgical adhesion formation with tranilast

BACKGROUND

Preclinical studies using the rabbit sidewall and double uterine horn models were used to assess time and dose response of tranilast delivered via subcutaneous pump, p.o., or as an intraperitoneal bolus in viscoelastic gels as well as an intraperitoneal biodegradable poly(p-dioxanone) fiber in reducing adhesions compared to vehicle controls.

MATERIALS AND METHODS

New Zealand white rabbits underwent laparotomy followed by: 1) uterine horn abrasion and peripheral devascularization or 2) cecal abrasion and sidewall deperitonealization. Tranilast treatment using various vehicles and dosages was compared to vehicle alone versus no treatment. Animals were euthanized after 7 to 21 days. Adhesion formation was assessed by two independent observers.

RESULTS

There were reductions in adhesion formation when drug was delivered topically, but oral drug alone was not effective. When tranilast was given preoperatively, oral drug added to the adhesion reduction of intraperitoneal administered drug. Tranilast in a viscoelastic carrier as well as in a biodegradable fiber was effective at reducing adhesions in the double uterine horn model. The slow release of tranilast from a biodegradable rod produced overall the best results. There were no safety issues.

CONCLUSION

Tranilast was effective in reducing adhesions when given in a variety of vehicles in different rabbit models of adhesion formation. Overall, the sustained intraperitoneal delivery of tranilast from biodegradable fibers was the most suitable for clinical testing.

Effect of tranilast in early-stage diabetic nephropathy

BACKGROUND

Tranilast is an antifibrotic drug known to suppress collagen synthesis by fibroblasts by interfering with the effects of TGF-beta. We recently reported that it slowed the progression rate of advanced diabetic nephropathy (DN) by reducing the accumulation of collagens in renal tissue. The present study was undertaken to examine the effect of tranilast on early-stage DN.

METHODS

Among out-patients with diabetes mellitus, we selected patients with (i) urinary albumin excretion of 30-1000 mg/g creatinine (/gCr) in the first morning urine, (ii) serum creatinine (SCr) < or =1.2 mg/dl and no haematuria and (iii) currently taking an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. Twenty patients fulfilled the criteria, of whom 10 were selected at random and commenced on tranilast [100 mg, 3 times daily; T(+) group]. The remaining 10 patients comprised the T(-) group. Excretion of both urinary type IV collagen (U-IV) and albumin (U-A) in the first morning urine was measured every 3 months. The follow-up period was 1 year.

RESULTS

At baseline, no significant differences were observed in SCr, HbA(1c), blood pressure and U-A excretion between the T(+) and T(-) groups, but U-IV excretion in the T(+) group was higher than in the T(-) group (6.4 +/- 0.66 vs 3.7 +/- 0.36 microg/gCr, mean +/- SEM, P < 0.01). At 1 year, SCr was not different from the baseline in either group. In the T(+) group, however, excretion rates of both U-IV and U-A tended to decrease with time, and after 1 year, were significantly decreased compared with excretion at baseline (U-A: 279 +/- 78 to 191 +/- 62 mg/gCr; P = 0.049, U-IV: 6.4 +/- 0.66 to 4.4 +/- 0.99 microg/gCr; P = 0.02). In contrast, in the T(-) group, excretion of both U-A and U-IV tended to increase with time. The changes of both U-A and U-IV excretions in the two groups took statistically different trends through tranilast treatment (P = 0.01 and P = 0.04, respectively).

CONCLUSIONS

Our results suggest that tranilast could be therapeutically beneficial in early-stage DN.

Tranilast attenuates connective tissue growth factor-induced extracellular matrix accumulation in renal cells

Tranilast (N-[3,4-dimethoxycinnamoyl]anthranilic acid) is a synthetic compound that we have recently reported to inhibit transforming growth factor-beta1 (TGF-beta1)-induced tubulointerstitial fibrosis in the kidney. Connective tissue growth factor (CTGF) is recognized as a potent downstream mediator of TGF-beta1. Both proximal tubule cells (PTCs) and cortical fibroblasts (CFs) are considered to be responsible for the production of tubulointerstitial extracellular matrix (ECM). These studies were undertaken to assess the profibrotic effects of CTGF in an in vitro model of the human PTCs and CFs, and to determine whether tranilast is effective in limiting the in vitro matrix responses induced by CTGF. Primary cultures of PTCs and CFs were exposed to CTGF (20 ng/ml)+/-tranilast (100 microM). Cell hypertrophy and the secretion of the ECM proteins fibronectin and collagen IV were determined. The effects of tranilast on TGF-beta1-induced CTGF mRNA expression and on phosphorylation of Smad2 were determined. CTGF significantly induced cell hypertrophy, increased fibronectin, and collagen IV secretion in PTCs and CFs. In all cases, the CTGF-induced increase in ECM protein was inhibited in the presence of tranilast. Tranilast reduced CTGF mRNA and phosphorylation of Smad2, which were induced by TGF-beta1 in PTCs and CFs. These results suggest that tranilast is a potential effective antifibrotic compound in the kidney, exerting its effects via inhibition of TGF-beta1-induced CTGF expression and downstream activation of the Smad2 pathway in both PTCs and CFs.

Liquid chromatographic/tandem mass spectrometric method for the quantitation of tranilast in human plasma

An analytical method for the determination of tranilast in human plasma using tramadol as the internal standard has been developed based on liquid chromatography/tandem mass spectrometry. Sample preparation involved protein precipitation with methanol. Separation by reversed-phase high-performance liquid chromatography using methanol/10 mM ammonium acetate (70: 30, v/v) as mobile phase was complete in a run time of 2.4 min. Detection on a Q TRAP system used multiple reaction monitoring. The method was linear in the range 0.06-20 microg/mL with intra- and inter-day precisions (as relative standard deviation) of 2.2-2.6% and 2.3-2.9%, respectively. Accuracy (as relative error) was <-2.5%. The method was applied in a pharmacokinetic study in healthy volunteers treated with a single 80 mg oral dose of tranilast.

Tranilast: A novel weapon against insulin resistance

Oxidative stress and inflammatory cytokines such as monocyte chemoattractant protein 1 (MCP-1), TGF-beta, and IL-2 are supposed to play crucial roles in the pathogenesis of insulin resistance (IR). Tranilast is an anti-allergic drug which exerts anti-inflammatory and anti-angiogenesis effects through inhibition of expression of MCP-1, TGF-beta, and antigen-induced IL-2 lymphocyte responsiveness. It also possesses a certain antioxidant activity. Considering the above facts and in view of its safety, tranilast may prove invaluable in the treatment of IR.

The antiatherogenic potential of oat phenolic compounds

Avenanthramides are phenolic antioxidants, which are present in oats. Avenanthramides A, B, and C are the major constituents of the total soluble antioxidant phenolic compounds in oats. We tested the potential antiatherogenic activity of partially purified avenanthramides from oats by examining their effects on adhesion of monocytes to human aortic endothelial cell (HAEC) monolayers, expression of adhesion molecules, and production of proinflammatory cytokines and chemokines by HAEC. The oat avenanthramides mixture was prepared and partially purified by column chromatography. This avenanthramide-enriched mixture (AEM) had no toxicity to HAEC as tested up to 40 ng/ml. The pre-incubation of HAEC with 4, 20, and 40ng/ml AEM for 24h significantly decreased adhesion of U937 monocytic cells to interleukin (IL)-1beta-stimulated HAEC in a concentration-dependent manner. Pre-incubation of HAEC with AEM at 20 and 40 microg/ml, but not at 4 microg/ml, for 24h significantly suppressed IL-1beta-stimulated expressions of intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin and the secretion of proinflammatory cytokines IL-6, chemokines IL-8 and monocyte chemoattractant protein (MCP)-1. These data provide evidence for the potential anti-inflammatory and antiatherogenic effects of antioxidant avenanthramides present in oats.

Tranilast attenuates myocardial fibrosis in association with suppression of monocyte/macrophage infiltration in DOCA/salt hypertensive rats

OBJECTIVE

In order to study the association between myocardial fibrosis and inflammatory cell infiltration in the hypertensive heart, we investigated whether N(3,4-dimethoxycinnamoyl) anthranilic acid (tranilast), an anti-inflammatory drug, would suppress myocardial fibrosis via inhibition of inflammatory cell infiltration in deoxycorticosterone-acetate (DOCA) hypertensive rats.

METHODS

Sprague-Dawley rats treated with DOCA combined with the addition of 1% NaCl and 0.2% KCl in the drinking water after left nephrectomy were given tranilast (100 mg/kg per day, n = 15) or vehicle (n = 15) for up to 4 weeks. Systolic blood pressure (SBP), amount of myocardial interstitial fibrosis, perivascular fibrosis and type I and III collagen, and mRNA expression of procollagen I (PI) and procollagen III (PIII), transforming growth factor (TGF)-beta1, type-1 plasminogen activator inhibitor (PAI-1), monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6 were determined.

RESULTS

SBP was increased significantly 2 weeks after treatment with DOCA and salt. Myocardial interstitial fibrosis, perivascular fibrosis and collagen accumulation increased significantly 4 weeks after the treatment. Two weeks after the treatment with DOCA and salt, mRNA expression of PI and PIII, TGF-beta1, PAI-1, MCP-1 and IL-6 increased significantly. Although the SBP was similar in animals treated with tranilast or vehicle, monocyte/macrophage infiltration was suppressed, mRNA expression of TGF-beta1, PAI-1, MCP-1, IL-6, PI and PIII was attenuated, and myocardial fibrosis and collagen accumulation were suppressed in hypertensive animals receiving tranilast.

CONCLUSION

Myocardial fibrosis seen in DOCA/salt hypertensive rats might be associated with the inflammation/wound healing response. Tranilast suppresses both infiltration of monocytes/macrophages and myocardial fibrosis.

Preventive Effect of Tranilast on Oleic Acid-Induced Lung Injury in Guinea Pigs

Acute respiratory distress syndrome or acute lung injury (ARDS)/(ALI) involve the severe lung injury with pulmonary vascular hyper-permeability and hypoxemia induced by inflammatory reactions. Since ARDS/ALI carries high mortality, the development of new drugs against ARDS/ALI is required. We examined the effect of tranilast, an anti-allergic drug, on vascular hyper-permeability in the lungs and airways, and on hypoxemia, in oleic acid (OA)-induced acute lung injury, an animal model of ARDS/ALI. The increase in pulmonary and airway vascular permeability and the decrease in partial oxygen pressure of arterial blood induced by an intravenous injection of OA were drastically ameliorated by the oral administration of tranilast in a dose-dependent manner. This is the first report to prove that tranilast prevents pulmonary and airway vascular permeability and hypoxemia induced by OA. These results suggest that tranilast may be a candidate drug for the treatment of ARDS/ALI.

Involvement of protein kinase Cδ and extracellular signal-regulated kinase-2 in the suppression of microglial inducible nitric oxide synthase expression by N-[3,4-dimethoxycinnamoyl]-anthranilic acid (tranilast)

Excess nitric oxide (NO) in the brain released by microglial cells contributes to neuronal damage in various pathologies of the central nervous system (CNS) including neurodegenerative diseases and multiple sclerosis. N-[3,4-Dimethoxycinnamoyl]-anthranilic acid (tranilast, TNL) is an anti-allergic compound which suppresses the activation of monocytes. We show that inducible nitric oxide synthase (iNOS) mRNA and protein expression and the release of NO from N9 microglial cells stimulated with the bacterial endotoxin lipopolysaccharide (LPS) are inhibited when the cells are exposed to TNL. TNL fails to modulate LPS-stimulated nuclear factor-kappaB (NF-kappaB) reporter gene activity and phosphorylation of inhibitory kappaB (IkappaB), indicating that NF-kappaB is not involved in the TNL-mediated suppression of LPS-induced iNOS expression. Moreover, TNL inhibits LPS-induced phosphorylation of extracellular signal-regulated kinase 2 (ERK-2). Finally, TNL abolishes translocation of protein kinase Cdelta (PKCdelta) to the nucleus and suppresses the phosphorylation of the PKCdelta substrate, myristoylated alanin-rich C kinase substrate (MARCKS). We conclude that the anti-allergic compound TNL suppresses microglial iNOS induction by LPS via inhibition of a signalling pathway involving PKCdelta and ERK-2.

Involvement of p38 MAPK, JNK, p42/p44 ERK and NF-kappaB in IL-1beta-induced chemokine release in human airway smooth muscle cells

Asthma is an inflammatory disease, in which eotaxin, MCP-1 and MCP-3 play a crucial role. These chemokines have been shown to be expressed and produced by IL-1beta-stimulated human airway smooth muscle cells (HASMC) in culture. In the present study we were interested to unravel the IL-1beta-induced signal transduction leading to chemokine production. Using Western blot, we observed an activation of p38 MAPK, JNK kinase and p42/p44 ERK when HASMC were stimulated with IL-1beta. We also observed a significant decrease in the expression and the release of eotaxin, MCP-1 and MCP-3 in the presence of SB203580, an inhibitor of p38 MAPK (71 +/- 6%, P < 0.05, n = 8 and 39 +/- 10% P < 0.01, n = 10 respectively), curcumin, an inhibitor of JNK kinase (83 +/- 4.9% and 88 +/- 3.4% respectively, P < 0.01, n = 4). U0126, an inhibitor of p42/p44 ERK, also produced a significant decrease in chemokine production (46.3 +/- 9%, P < 0.01 n = 10 and 67.8 +/- 12%, P < 0.01, n = 12). Pyrrolydine dithiocarbamate, an inhibitor of NF-kappaB was also able to reduce the eotaxin, MCP-1 and MCP-3 expression and production (50 +/- 13%, P < 0.05, n = 10 and 23 +/- 7%, P < 0.05, n = 12). We conclude that p38 MAPK, JNK kinase, ERK and NF-kappaB are involved in the IL-1beta-induced eotaxin, MCP-1, and MCP-3 expression and release in HASMC.

Bone morphogenetic protein-7 inhibits constitutive and interleukin-1 beta-induced monocyte chemoattractant protein-1 expression in human mesangial cells: role for JNK/AP-1 pathway

Bone morphogenetic protein-7 (BMP-7), which belongs to the TGF-beta superfamily, has been shown to reduce macrophage infiltration and tissue injury in animal models of inflammatory renal disease. To explore the mechanism involved in the anti-inflammatory effect, we investigated the effect of BMP-7 on monocyte chemoattractant protein-1 (MCP-1) expression in cultured human mesangial cells. BMP- 7 significantly inhibited constitutive and IL-1 beta-induced MCP-1 protein production and MCP-1 mRNA expression by mesangial cells in a time- and concentration-dependent manner. BMP-7 also inhibited IL-1 beta-induced monocyte chemotactic activity released from the mesangial cells. We examined the role of transcription factors NF-kappa B and AP-1 in BMP-7 inhibition of IL-1 beta-induced MCP-1 expression. IL-1 beta increased NF-kappa B and AP-1 activity and both transcription factors mediated IL-1 beta-induced MCP-1 expression in mesangial cells. BMP-7 inhibited IL-1 beta-induced AP-1 activity in a concentration-dependent manner. In contrast, IL-1 beta-induced NF-kappa B activity and I kappa B alpha degradation were not affected by BMP-7. Furthermore, IL-1 beta-induced phosphorylation of c-Jun N-terminal kinase was inhibited by BMP-7. These data suggest that BMP-7 inhibits constitutive and IL-1 beta-induced MCP-1 expression in human mesangial cells partly by inhibiting c-Jun N-terminal kinase activity and subsequent AP-1 activity, and provide new insight into the therapeutic potential of BMP-7 in the inflammatory renal diseases.

Interleukin-1beta stimulates macrophage inflammatory protein-1alpha and -1beta expression in human neuronal cells (NT2-N)

Chemokines are important mediators in immune responses and inflammatory processes of neuroimmunologic and infectious diseases. Although chemokines are expressed predominantly by cells of the immune system, neurons also express chemokines and chemokine receptors. We report herein that human neuronal cells (NT2-N) produce macrophage inflammatory protein-1alpha and -1beta (MIP-1alpha and MIP-1beta), which could be enhanced by interleukin (IL)-1beta at both mRNA and protein levels. The addition of supernatants from human peripheral blood monocyte-derived macrophage (MDM) cultures induced MIP-1beta mRNA expression in NT2-N cells. Anti-IL-1beta antibody removed most, but not all, of the MDM culture supernatant-induced MIP-1beta mRNA expression in NT2-N cells, suggesting that IL-1beta in the MDM culture supernatants is a major factor in the induction of MIP-1beta expression. Investigation of the mechanism(s) responsible for IL-1beta-induced MIP-1alpha and -1beta expression demonstrated that IL-1beta activated nuclear factor kappa B (NF-kappaB) promoter-directed luciferase activity in NT2-N cells. Caffeic acid phenethyl ester, a potent and specific inhibitor of activation of NF-kappaB, not only blocked IL-1beta-induced activation of the NF-kappaB promoter but also decreased IL-1beta-induced MIP-1alpha and -1beta expression in NT2-N cells. These data suggest that NF-kappaB is at least partially involved in the IL-1beta-mediated action on MIP-1alpha and -1beta in NT2-N cells. IL-1beta-mediated up-regulation of beta-chemokine expression may have important implications in the immunopathogenesis of inflammatory diseases in the CNS.