Identification of Small Molecule Inhibitors of the Pathogen Box against Vibrio cholerae.

Antimicrobial resistance (AMR) has become a serious public and economic threat. The rate of bacteria acquiring AMR surpasses the rate of new antibiotics discovery, projecting more deadly AMR infections in the future. The Pathogen Box is an open-source library of drug-like compounds that can be screened for antibiotic activity. We have screened molecules of the Pathogen Box against Vibrio cholerae, the cholera-causing pathogen, and successfully identified two compounds, MMV687807 and MMV675968, that inhibit growth. RNA-seq analyses of V. cholerae after incubation with each compound revealed that both compounds affect cellular functions on multiple levels including carbon metabolism, iron homeostasis, and biofilm formation. In addition, whole-genome sequencing analysis of spontaneous resistance mutants identified an efflux system that confers resistance to MMV687807. We also identified that the dihydrofolate reductase is the likely target of MMV675968 suggesting it acts as an analog of trimethoprim but with a MIC 14-fold lower than trimethoprim in molar concentration. In summary, these two compounds that effectively inhibit V. cholerae and other bacteria may lead to the development of new antibiotics for better treatment of the cholera disease. IMPORTANCE Cholera is a serious infectious disease in tropical regions causing millions of infections annually. Vibrio cholerae, the causative agent of cholera, has gained multi-antibiotic resistance over the years, posing greater threat to public health and current treatment strategies. Here we report two compounds that effectively target the growth of V. cholerae and have the potential to control cholera infection.

Red Pepper (Capsicum annuum L.) Seed Extract Decreased Hepatic Gluconeogenesis and Increased Muscle Glucose Uptake In Vitro.

Red pepper seed, a by-product of red pepper, has been reported to have antioxidant and antiobesity activities. However, its role in diabetes has not yet been highly investigated. Glucose homeostasis is mainly maintained by insulin, which suppresses glucose production in the liver and enhances glucose uptake in peripheral tissues. In this study, we investigated the underlying mechanisms through which red pepper seed extract (RPSE) affects glucose production in AML12 hepatocytes and glucose uptake in C2C12 myotubes. RPSE reduced glucose production in a dose-dependent manner in AML12 cells. The levels of glucose 6 phosphatase, phosphoenolpyruvate carboxykinase, and critical enzymes for hepatic gluconeogenesis were decreased by RPSE. Gluconeogenesis regulating proteins, Akt and forkhead box protein O1, were also activated by RPSE. In addition, RPSE increased glucose uptake in C2C12 via inducing translocation of glucose transporter type 4 from cytosol to plasma membrane. Analysis of the insulin-dependent pathway showed that the activities of insulin receptor substrate 1, phosphatidylinositol 3-kinase, and Akt were significantly stimulated by RPSE. In conclusion, RPSE might improve glucose homeostasis by reducing hepatic gluconeogenesis and increasing peripheral glucose uptake. Results obtained also suggest that RPSE can be a compelling antidiabetic nutraceutical.

Medium-Chain Enriched Diacylglycerol (MCE-DAG) Oil Decreases Body Fat Mass in Mice by Increasing Lipolysis and Thermogenesis in Adipose Tissue.

Medium chain fatty acid (MCFA) escapes the formation of chylomicrons in the small intestine, resulting in energy expenditure through beta-oxidation. Diacylglycerol (DAG) is susceptible to oxidation rather than being stored in the adipose tissue. This study was conducted to verify the effect of MCE-DAG oil on body fat mass in vivo. Male C57BL/6 mice were randomly assigned to four groups (n = 12) as follows: (1) normal diet (18% kcal from fat), (2) canola oil as a control (40% kcal from canola oil), (3) MCE-DAG10 (10% kcal from MCE-DAG + 30% kcal from canola oil), and (4) MCE-DAG20 (20% kcal from MCE-DAG + 20% kcal from canola oil). The body weight and fat mass of MCE-DAG20 group mice were decreased relative to those of control mice (P < 0.05 and P < 0.001, respectively). Serum triacylglycerol (TAG) was decreased in both MCE-DAG10 and MCE-DAG20 groups (P < 0.01 and P < 0.05, respectively). Hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) were increased in the MCE-DAG20 group relative to the control in white adipose tissue (WAT) (P < 0.05). Uncoupling protein 1 (UCP1) was also increased in the MCE-DAG20 group relative to the control in brown adipose tissue (BAT) (P < 0.05). In summary, MCE-DAG reduced body fat mass likely by stimulating lipolysis in WAT and thermogenesis in BAT.