Anti-virulence and bactericidal activities of Stattic against Shigella sonnei.

IMPORTANCE: Shigella sonnei is a major human enteric pathogen that causes bacillary dysentery. The increasing spread of drug-resistant S. sonnei strains has caused an emergent need for the development of new antimicrobial agents against this pathogenic bacterium. In this study, we demonstrate that Stattic employs two antibacterial mechanisms against S. sonnei. It exerted both anti-virulence activity and bactericidal activity against S. sonnei, suggesting that it shows advantages over traditional antibiotics. Moreover, Stattic showed excellent synergistic effects with kanamycin, ampicillin, chloramphenicol, and gentamicin against S. sonnei. Our findings suggest that Stattic has promising potential for development as a new antibiotic or as an adjuvant to antibiotics for infections caused by S. sonnei.

LMWP (S3-3) from the Larvae of Musca domestica Alleviate D-IBS by Adjusting the Gut Microbiota.

Diarrhea-based Irritable Bowel Syndrome (D-IBS) and diarrhea are both associated with ecological imbalance of the gut microbiota. Low Molecular Weight Peptides (LMWP) from the larvae of Musca domestica have been shown to be effective in the treatment of diarrhea and regulation of gut microbiota. Meanwhile, the single polypeptide S3-3 was successfully isolated and identified from LMWP in our previous studies. It remains unclear exactly whether and how LMWP (S3-3) alleviate D-IBS through regulating gut microbiota. We evaluated the gut microbiota and pharmacology to determine the regulation of gut microbiota structure and the alleviating effect on D-IBS through LMWP (S3-3). The rates of loose stools, abdominal withdrawal reflex (AWR) and intestinal tract motility results revealed that LMWP (S3-3) from the larvae of Musca domestica had a regulating effect against diarrhea, visceral hypersensitivity and gastrointestinal (GI) dysfunction in D-IBS model mice. Additionally, 16S rRNA gene sequencing was utilized to examine the gut microbiota, which suggests that LMWP induce structural changes in the gut microbiota and alter the levels of the following gut microbiota: Bacteroidetes, Proteobacteria and Verrucomicrobia. LMWP putatively functioned through regulating 5-HT, SERT, 5-HT2AR, 5-HT3AR and 5-HT4R according to the results of ELISA, qRT-PCR and IHC. The findings of this study will contribute to further understanding how LMWP (S3-3) attenuate the effects of D-IBS on diarrhea, visceral hypersensitivity and GI dysfunction.

Beneficial effect of simvastatin on human umbilical vein endothelial cells gap junctions induced by TNF-α.

Although simvastatin has been shown to inhibit vascular permeability, which might be amplified via gap junction intercellular communication (GJIC), the underlying mechanism of action remains unclear. In the present study, we investigated the effects and mechanisms of simvastatin on endothelial cells GJIC. Specifically, human umbilical vein endothelial cells (HUVECs) were stimulated with TNF-α (10 ng/mL) alone or in combination with simvastatin (5 µM), and their effects on vascular endothelial cell GJIC tested via the scrape loading/dye transfer (SL/DT) assay. Next, we performed immunofluorescence, real-time PCR and western blot assays to analyze expression of Cx37, Cx40 and Cx43 in HUVECs. Results showed that GJIC activity in HUVECs was markedly elevated in HUVECs treated with TNF-α in combination with simvastatin. In addition, simvastatin treatment significantly upregulated expression of Cx37 and Cx40 but downregulated Cx43 mRNAs and proteins. Taken together, these marked changes indicated that simvastatin exerts its regulatory effects on gap junction function by upregulating Cx37 and Cx40 and downregulating Cx43 expression.

Effects of Chang-Kang-Fang Formula on the Microbiota-Gut-Brain Axis in Rats With Irritable Bowel Syndrome.

Chang-Kang-Fang formula (CKF), a multi-herb traditional Chinese medicine, has been used in clinical settings to treat irritable bowel syndrome (IBS). Recent studies show that 5.0 g/kg/d CKF can alleviate the symptoms of IBS rats by modulating the brain-gut axis through the production of brain-gut peptides (BGPs), thus relieving pain, and reversing the effects of intestinal propulsion disorders. However, the exact mechanisms underlying the therapeutic effects of CKF in IBS remain unclear. The microbiota-gut-brain axis (MGBA) is central to the pathogenesis of IBS, regulating BGPs, depression-like behaviors, and gut microbiota. Given that CKF ameliorates IBS via the MGBA, we performed metabolomic analyses, evaluated the gut microbiota, and system pharmacology to elucidate the mechanisms of action of CKF. The results of intestinal tract motility, abdominal withdrawal reflex (AWR), sucrose preference test (SPT), and the forced swimming test (FST) showed that the male Sprague-Dawley rats subjected to chronic acute combining stress (CACS) for 22 days exhibited altered intestinal motility, visceral hypersensitivity, and depression-like behaviors. Treatment of IBS rats with CKF normalized dysfunctions of CACS-induced central and peripheral nervous system. CKF regulated BDNF and 5-HT levels in the colon and hippocampus as well as the expressions of the related BGP pathway genes. Moreover, the system pharmacology assays were used to assess the physiological targets involved in the action of CKF, with results suggesting that CKF putatively functioned through the 5-HT-PKA-CREB-BDNF pathway. LC-MS-based metabolomics identified the significantly altered 5-HT pathway-related metabolites in the CKF treatment group, and thus, the CKF-related signaling pathways were further examined. After pyrosequencing-based analysis of bacterial 16S rRNA (V3 + V4 region) using rat feces, the Lefse analysis of gut microbiota suggested that CKF treatment could induce structural changes in the gut microbiota, thereby regulating it by decreasing Clostridiales, and the F-B ratio while increasing the levels of Lactobacillus. Furthermore, the integrated analysis showed a correlation of CKF-associated microbes with metabolites. These findings showed that CKF effectively alleviated IBS, which was associated with the altered features of the metabolite profiles and the gut microbiota through a bidirectional communication along the microbiota-gut-brain axis.