Nafamostat mesylate, a serine protease inhibitor, demonstrates novel antimicrobial properties and effectiveness in Chlamydia-induced arthritis

Abstract

IntroductionEffective treatment of reactive arthritis would ideally achieve both control of inflammation and eradication of persisting arthritogenic pathogens. We use a model of experimental Chlamydia trachomatis-induced arthritis (CtIA) to evaluate the effectiveness of nafamostat mesilate (NM), a serine protease inhibitor with complement-modifying effects and anticoagulant properties. To date clinical use of NM has largely been in Asia and has been primarily confined to inflammatory states such as pancreatitis.MethodsIn vitro studies examined inhibition of Chlamydia proliferation using fibroblast cell lines as targets and phase contrast microscopy. In vivo studies used an established protocol, experimental CtIA, induced in Lewis rats by injection of synoviocyte-packaged C. trachomatis. NM was dissolved in water and administered by daily intraperitoneal injection at a dose of 10 mg/kg beginning the day prior to the administration of Chlamydia. Readouts in vivo included (i) joint swelling, (ii) histopathology scoring of severity of arthritis, (iii) host clearance of the pathogen (by ELISA, the IDEIA PCE Chlamydia).ResultsNM exerted a dose-dependent inhibition of chlamydial proliferation in vitro. Without NM, the mean number of inclusion bodies (IB) per well was 17,886 (± 1415). At 5 μg/mL NM, there were 8,490 (± 756) IB, at 25 μg/mL NM there were 35 IB and at 50 μg/mL NM no IB was observed. Chlamydial antigens in each well along the concentration gradient were assayed by ELISA, demonstrating that at 25 μg/mL NM inhibition of Chlamydia was almost complete. In the experimental arthritis model, joint swelling was significantly reduced with NM treatment: average joint width for the NM-treated animals was 8.55 mm (s.d. ± 0.6578, n = 10) versus 11.18 mm (s.d. ± 0.5672, n = 10) in controls (P < 0.001). Histopathology scoring indicated that NM resulted in a marked attenuation of the inflammatory infiltration and joint damage: mean pathology score in NM-treated animals was 10.9 (± 2.45, n = 11) versus 15.9 (± 1.45, n = 10) in controls (P < 0.0001). With respect to persistence of Chlamydia within the synovial tissues, NM treatment was accompanied by a reduction in the microbial load in the joint: mean optical density (O.D.) for ELISA with NM treatment was 0.05 (± 0.02, n = 4) versus 0.18 (± 0.05, n = 4) in controls (P < 0.001).ConclusionsNM is a protease inhibitor not previously recognized to possess antimicrobial properties. The present study demonstrates for the first time that NM exerts significant impact on C. trachomatis-induced arthritis and suggests that such approaches may prove clinically useful in chronic reactive arthritis.

Design, Virtual Screening, and Synthesis of Antagonists of αIIbβ3 as Antiplatelet Agents

“…This compound was also identified by Negri et al in their structure-based virtual screening . Nafamostat has some clear drawbacks: it does not possess high antiaggregation activity (IC 50 = 12.5 μM), and it may have some side effects because of its ability to bind different proteins, such as thrombin, urokinase, trypsin, plasmin, etc. − It should, however, be noted that Nafamostat was introduced as an alternative anticoagulant in continuous renal replacement therapy (CRRT) in 1990, but its usage is mainly limited to Japan. , Another selected compound, N -[( E )-[1-(2-{5-[(1 E )-1-(carbamimidamidoimino)­ethyl]-4-methyl-1,3-thiazol-2-yl}-4-methyl-1,3-thiazol-5-yl)­ethylidene]­amino]­guanidine, was not available for purchasing at that moment.…”

The Molecular Aspect of Antitumor Effects of Protease Inhibitor Nafamostat Mesylate and Its Role in Potential Clinical Applications

“…As for antimicrobial activity of NM, Inman et al found that NM exerts a dose-dependent inhibition of chlamydial infection. The in vitro and in vivo models showed that NM could effectively minimized pathological features of chlamydial-induced arthritis, including inflammatory infiltration and joint damage (85). Additionally, NM could inhibit middle east respiratory syndrome coronavirus infections (86) and the ebola virus disease in in vitro studies (87).…”

The discovery and development of transmembrane serine protease 2 (TMPRSS2) inhibitors as candidate drugs for the treatment of COVID-19

“…Nafamostat has been recognized for its antimicrobial and antiviral properties. Specifically, nafamostat mesilate exhibited in vitro inhibition of Chlamydia proliferation and proved to be effective against Chlamydia-induced arthritis [ 75 ]. In the case of viruses, nafamostat mesilate has been effective against influenza virus type A and B in MDCK cells, with EC 50 s of 0.44 and 1.5 μg/mL, respectively.…”