3-Hydroxykynurenamine, also known as 3-Hydroxy-L-kynurenamine or 3-HKA, is a biogenic amine produced via an alternative pathway of tryptophan metabolism. In vitro, 3-HKA has an anti-inflammatory profile by inhibiting the IFN-γ mediated STAT1 NF-κΒ pathway in both mouse and human dendritic cells (DCs) with a consequent decrease in the release of pro-inflammatory chemokines and cytokines, most notably TNF, IL-6, and IL12p70. 3-HKA has protective effects in an experimental mouse model of psoriasis by decreasing skin thickness, erythema, scaling and fissuring, reducing TNF, IL-1β, IFN-γ, and IL-17 production, and inhibiting generation of effector CD8+ T cells. Similarly, in a mouse model of nephrotoxic nephritis, besides reducing inflammatory cytokines, 3-HKA improves proteinuria and serum urea nitrogen, overall ameliorating immune-mediated glomerulonephritis and renal dysfunction.This compound is unstable in powder form and other related salt forms are recommended.
Talabostat (PT100, Val-boroPro) is a potent, nonselective and orally available dipeptidyl peptidase IV (DPP-IV) inhibitor with a Ki of 0.18 nM. Talabostat is a nonselective DPP-IV inhibitor, inhibiting DPP8 9, FAP, DPP2 and some other DASH family enzymes essentially as potently as it inhibits DPP-IV[1]. Talabostat stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. The inhibition of two serine proteases, DPP8 and DPP9, activates the proprotein form of caspase-1 independent of the inflammasome adaptor ASC[2]. Talabostat competitively inhibits the dipeptidyl peptidase (DPP) activity of FAP and CD26 DPP-IV, and there is a high-affinity interaction with the catalytic site due to the formation of a complex between Ser630 624 and the boron of talabostat[3]. Talabostat can stimulate immune responses against tumors involving both the innate and adaptive branches of the immune system. In WEHI 164 fibrosarcoma and EL4 and A20 2J lymphoma models, PT-100 causes regression and rejection of tumors. The antitumor effect appears to involve tumor-specific CTL and protective immunological memory. Talabostat treatment of WEHI 164-inoculated mice increases mRNA expression of cytokines and chemokines known to promote T-cell priming and chemoattraction of T cells and innate effector cells[3]. Talabostat treated mice show significant less fibrosis and FAP expression is reduced. Upon PT100 treatment, significant differences in the MMP-12, MIP-1α, and MCP-3 mRNA expression levels in the lungs are also observed. Treatment with PT100 in this murine model of pulmonary fibrosis has an anti-fibro-proliferative effect and increases macrophage activation[4]. [1]. Connolly BA, et al. Dipeptide boronic acid inhibitors of dipeptidyl peptidase IV: determinants of potencyand in vivo efficacy and safety. J Med Chem. 2008 Oct 9;51(19):6005-13. [2]. Okondo MC, et al. DPP8 and DPP9 inhibition induces pro-caspase-1-dependent monocyte and macrophage pyroptosis. Nat Chem Biol. 2017 Jan;13(1):46-53. [3]. Adams S, et al. PT-100, a small molecule dipeptidyl peptidase inhibitor, has potent antitumor effects and augments antibody-mediated cytotoxicity via a novel immune mechanism. Cancer Res. 2004 Aug 1;64(15):5471-80. [4]. Egger C, et al. Effects of the fibroblast activation protein inhibitor, PT100, in a murine model of pulmonary fibrosis. Eur J Pharmacol. 2017 Aug 15;809:64-72.
AMG 487 is an effective and selective antagonist of chemokine receptor 3. AMG 487 inhibited CXCR3-mediated cell migration induced by three CXCR3 chemokines, IP-10, ITAC and MIG (IC50: 8, 15 and 36 nM, respectively).
Antileukinate is a synthetic hexapeptide with an acetylated amino terminus and an amidated carboxyl terminus that inhibits the binding of CXC chemokines to the chemokine receptor CXCR2. It inhibits IL-8 binding to neutrophils (Ki = 2.7-13 μM), prevents neutrophil chemotaxis and β-glucuronidase release, and blocks IL-8-induced skin edema in rabbits. At 53 mg/kg, antileukinate has been shown to protect mice against acute pancreatitis and associated lung injury.
IMMH001, also known as SYL930, is an orally active compound that exhibits potent selectivity as an agonist for the S1P1 receptor, which is the sphingosine-1-phosphate receptor 1. This compound effectively reduces the levels of various chemokines and proinflammatory cytokines, such as IL-1β, IL-5, IL-18, IP10, CCL3, and CCL5. IMMH001 finds utility in research focused on rheumatoid arthritis (RA) [1] [2].