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.
OPC-167832 is a potent and orally active dprE1 Inhibitor with an IC50 of 0.258 μM. OPC-167832 has antituberculosis activity and can be used for the research of tuberculosis caused by Mycobacterium tuberculosis[1]. OPC-167832 exhibits very low MICs against laboratory strains of M. tuberculosis H37Rv (MIC: 0.0005 μg ml) and Kurono (MIC: 0.0005 μg ml) and strains with monoresistance to rifampin (RIF), isoniazid (INH), ethambutol (EMB), streptomycin (STR), and pyrazinamide (PZA) (MIC: 0.00024-0.001 μg ml). However, OPC-167832 has minimal or no activity against standard strains of nonmycobacterial aerobic and anaerobic bacteria[1].The IC90 values of OPC-167832 against intracellular M. tuberculosis strains H37Rv and Kurono are 0.0048 and 0.0027 μg ml, respectively. OPC-167832 shows bactericidal activity against intracellular M. tuberculosis at a low concentration, and the bactericidal activity is saturated at concentrations of 0.004 μg ml or higher[1]. OPC-167832 (oral administration; 0.625-10 mg kg) exhibits a good pharmacokinetic characteristic. The plasma reaches peak at 0.5 h to 1.0 h (tmax) and is eliminated with a half-life (t1 2) of 1.3 h to 2.1 h OPC-167832 distribution in the lungs is approximately 2 times higher than that in plasma, and the Cmax and AUCt of OPC-167832 in plasma and the lungs shows dose dependency[1].OPC-167832 (oral administration; 0.625-10 mg kg; 4 weeks) significantly reduces lung CFU compared to the vehicle group. The dose-dependent decrease of lung CFU is observed from 0.625 mg kg to 2.5 mg kg. In a M. tuberculosis Kurono-infected ICR female mice model. OPC-167832 combines with DMD, BDQ, or LVX via oral gavage exhibits significantly higher efficacies than each single agent alone[1].[1].OPC-167832 (oral gavage; 2.5 mg kg; combination with DCMB; 12 weeks) demonstrates the most potent efficacy when compares with DC, DCB. The lung CFU count after 6 weeks of treatment is below the detection limit, and at the end of just 8 weeks of treatment, the bacteria in the lungs of all the evaluated mice had already been eradicate[1]. [1]. Norimitsu Hariguchi, et al. OPC-167832, a Novel Carbostyril Derivative with Potent Antituberculosis Activity as a DprE1 Inhibitor.Antimicrob Agents Chemother. 2020 May 21;64(6):e02020-19.
7-Methylguanosine 5’-diphosphate (7-Methyl-GDP) sodium, a cap analog, can be used in the synthesis of mRNA cap analogues[1]. 7-Methylguanosine 5’-diphosphate sodium inhibits binding of eukaryotic initiation factors to reovirus capped mRNA and complex formation involving uncapped mRNA or 18 S rRNA[1].T. brucei mRNA decapping enzyme (TbDcp2) that cleaves 7-Methylguanosine 5’-diphosphate sodium from capped RNA to generate pRNA, a substrate for TbCe1[2]. [1]. Sonenberg N, et al. Nonspecific effect of m7GMP on protein-RNA interactions. J Biol Chem. 1978;253(19):6630-6632.[2]. Ignatochkina AV, et al. The messenger RNA decapping and recapping pathway in Trypanosoma. Proc Natl Acad Sci U S A. 2015;112(22):6967-6972.
(±)19(20)-EpDTE is an oxylipin and an oxidative metabolite of docosapentaenoic acid . It is formed via cytochrome P450 (CYP) metabolism of DPA and can be further metabolized to (±)19(20)-DiHDTE by epoxide hydrolase.
Deltorphin II is a peptide agonist of δ2-opioid receptors.1,2It is selective for δ-opioid receptors over μ- and κ-opioid receptors in radioligand bindings assays (Kis = 0.0033, >1, and >1 μM, respectively) and induces [35S]GTPγS binding in mouse brain membrane preparations (EC50= 0.034 μM). Deltorphin II (0.12 mg kg) decreases the infarction zone:risk zone ratio in a rat model of myocardial ischemia-reperfusion injury induced by coronary occlusion, an effect that can be reversed by the δ2-opioid receptor antagonist naltriben but not the δ1-opioid receptor antagonist BNTX.3Intrathecal administration of deltorphin II (15 μg animal) increases latency to withdraw in the paw pressure and tail-flick tests in rats.4 1.Raynor, K., Kong, H., Chen, Y., et al.Pharmacological characterization of the cloned κ-, δ-, and μ-opioid receptorsMol. Pharm.45(2)330-334(1994) 2.Scherrer, G., Befort, K., Contet, C., et al.The delta agonists DPDPE and deltorphin II recruit predominantly mu receptors to produce thermal analgesia: A parallel study of mu, delta and combinatorial opioid receptor knockout miceEur. J. Neurosci.19(8)2239-2248(2004) 3.Maslov, L.N., Barzakh, E.I., Krylatov, A.V., et al.Opioid peptide deltorphin II simulates the cardioprotective effect of ischemic preconditioning: role of δ2-opioid receptors, protein kinase C, and KATP channelsBull. Exp. Biol. Med.149(5)591-593(2010) 4.Labuz, D., Toth, G., Machelska, H., et al.Antinociceptive effects of isoleucine derivatives of deltorphin I and deltorphin II in rat spinal cord: A search for selectivity of delta receptor subtypesNeuropeptides32(6)511-517(1998)