RalA exerts an inhibitory effect on IL-1β/IL-18 secretion by blocking NLRP3 inflammasome activation in levornidazole-treated human THP-1 macrophages

NLR family pyrin domain containing 3 (NLRP3) inflammasomes and peripheral neuropathic pain - Emphasis on microRNAs (miRNAs) as important regulators

Neuropathic pain is caused by the lesion or disease of the somatosensory system and can be initiated and/or maintained by both central and peripheral mechanisms. Nerve injury leads to neuronal damage and apoptosis associated with the release of an array of pathogen- or damage-associated molecular patterns to activate inflammasomes. The activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome contributes to neuropathic pain and may represent a novel target for pain therapeutic development. In the current review, we provide an up-to-date summary of the recent findings on the involvement of NLRP3 inflammasome in modulating neuropathic pain development and maintenance, focusing on peripheral neuropathic conditions. Here we provide a detailed review of the mechanisms whereby NLRP3 inflammasomes contribute to neuropathic pain via (1) neuroinflammation, (2) apoptosis, (3) pyroptosis, (4) proinflammatory cytokine release, (5) mitochondrial dysfunction, and (6) oxidative stress. We then present the current research literature reporting on the antinociceptive effects of several natural products and pharmacological interventions that target activation, expression, and/or regulation of NLRP3 inflammasome. Furthermore, we emphasize the effects of microRNAs as another regulator of NLRP3 inflammasome. In conclusion, we summarize the possible caveats and future perspectives that might provide successful therapeutic approaches against NLRP3 inflammasome for treating or preventing neuropathic pain conditions.

A network pharmacology strategy combined with in vitro experiments to investigate the potential anti-inflammatory mechanism of Prunus cerasifera Ehrhart

This study aimed to investigate the anti-inflammatory activity of Prunus cerasifera Ehrhart (EHP). LC-MS/MS, network pharmacology, enzyme-linked immunosorbent assay (ELISA), and Western blot analysis methods were used to investigate the chemical composition and the anti-inflammatory mechanism of EHP. The LC-MS/MS results showed that flavonoids and phenolic acids were the major compounds in EHP. The network pharmacology analysis results indicated that EHP was related to TNF, inflammatory cytokine, and MAPK signaling pathway. ELISA and Western blot results showed that EHP impeded the increase in inflammatory factors, inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), nuclear transcription factors κB (p65), MAPK pathway, pyrolytic relevant proteins nod-like receptor family pyrin domain-containing 3 (NLRP3), and interleukin-1β (IL-1β) induced by lipopolysaccharide (LPS) and activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) pathway. Therefore, this research highlighted the potential application of P. cerasifera in the development of anti-inflammatory foods that prevented inflammatory diseases. PRACTICAL APPLICATIONS: In recent years, many synthetic drugs with anti-inflammatory effect have the disadvantages of high price and side effects. Thus, the development of anti-inflammatory drugs from natural resources has its application value. In this study, LPS-stimulated RAW264.7 cells were used to establish inflammatory model to verify the anti-inflammatory effect of Prunus cerasifera (EHP). The results showed that P. cerasifera possessed anti-inflammatory activity through inhibiting pro-inflammatory cytokines secretion, NF-κB, MAPK pathway, and NLRP3 inflammasome activation. Therefore, P. cerasifera has the potential to develop into functional food to prevent the progress of various inflammatory-related diseases.

Luteolin increases susceptibility to macrolides by inhibiting MsrA efflux pump in Trueperella pyogenes

Trueperella pyogenes (T. pyogenes) is an opportunistic pathogen associated with a variety of diseases in many domestic animals. Therapeutic treatment options for T. pyogenes infections are becoming limited due to antimicrobial resistance, in which efflux pumps play an important role. This study aims to evaluate the inhibitory activity of luteolin, a natural flavonoid, on the MsrA efflux pump and investigate its mechanism. The results of antimicrobial susceptibility testing indicated that the susceptibility of msrA-positive T. pyogenes isolates to six macrolides increased after luteolin treatment, while the susceptibility of msrA-negative isolates showed no change after luteolin treatment. It is suspected that luteolin may increase the susceptibility of T. pyogenes isolates by inhibiting MsrA activity. After 1/2 MIC luteolin treatment for 36 h, the transcription level of the msrA gene and the expression level of the MsrA protein decreased by 55.0-97.7% and 36.5-71.5%, respectively. The results of an affinity test showed that the equilibrium dissociation constant (KD) of luteolin and MsrA was 6.462 × 10-5 M, and hydrogen bonding was predominant in the interaction of luteolin and MsrA. Luteolin may inhibit the ATPase activity of the MsrA protein, resulting in its lack of an energy source. The current study illustrates the effect of luteolin on MsrA in T. pyogenes isolates and provides insight into the development of luteolin as an innovative agent in combating infections caused by antimicrobial-resistant bacteria.

Troxerutin Improves Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Screening potential compounds for improving ulcerative colitis (UC) from clinical medication is an effective strategy for drug repurposing. We applied bioinformatics and network pharmacology to the drug screening process in this study, which helped us to screen out troxerutin that could improve UC. Troxerutin belongs to flavonoids and is used clinically as an anticoagulant and thrombolytic agent. This study found a new pharmacological activity of troxerutin, that is, it had a significant improvement effect on UC in mice. Experimental results of in vitro and in vivo levels showed that troxerutin could effectively reduce the level of oxidative stress that caused damages in intestinal epithelial cells and colonic tissue, maintain the distribution and expression of tight junction-related proteins, and protect the barrier function of colon tissue. In addition to the oxidative stress, severe inflammatory response is also an important pathological factor that aggravates UC. However, troxerutin could reduce the infiltration of inflammatory cells in the colon tissue and decrease the expression of inflammation-related proteins and proinflammatory cytokines. Due to its antioxidant and anti-inflammatory effects, troxerutin inhibited the process of cell apoptosis in the colon tissue and relieved the degree of colonic fibrosis. Bioinformatics analysis showed that the ameliorating effect of troxerutin on UC was probably related to its network regulation of signaling pathways. In summary, we discovered a new pharmacological activity of the flavonoid troxerutin against UC, which is conducive to the expansion and application of flavonoids in the treatment of human diseases.