Depletion of Janus kinase-2 promotes neuronal differentiation of mouse embryonic stem cells.

Janus kinase 2 (JAK2), a non-receptor tyrosine kinase, is a critical component of cytokine and growth factor signaling pathways regulating hematopoietic cell proliferation. JAK2 mutations are associated with multiple myeloproliferative neoplasms. Although physiological and pathological functions of JAK2 in hematopoietic tissues are well-known, such functions of JAK2 in the nervous system are not well studied yet. The present study demonstrated that JAK2 could negatively regulate neuronal differentiation of mouse embryonic stem cells (ESCs). Depletion of JAK2 stimulated neuronal differentiation of mouse ESCs and activated glycogen synthase kinase 3ꞵ, Fyn, and cyclin-dependent kinase 5. Knockdown of JAK2 resulted in accumulation of GTPbound Rac1, a Rho GTPase implicated in the regulation of cytoskeletal dynamics. These findings suggest that JAK2 might negatively regulate neuronal differentiation by suppressing the GSK-3ß/Fyn/CDK5 signaling pathway responsible for morphological maturation. [BMB Reports 2021; 54(12): 626-631].

Fermented garlic protects diabetic, obese mice when fed a high-fat diet by antioxidant effects.

This study examined the bioactivity of yeast (Saccharomyces cerevisiae)-fermented aged black garlic (FBG) on obese mice supplied a high-fat diet (HFD) and its in vitro antioxidant activity. Aged black garlic (BG) exhibits potent antioxidative effects and has been subjected to extensive research. In addition, the bioactivity of some natural products is increased by fermentation. In a preliminary test, this study found that the antioxidant activity of FBG is stronger than that of BG. Therefore, it was hypothesized that the bioactivity of BG would be increased by yeast fermentation and would be a good candidate as a nutraceutical product for improving the oxidative defense systems in older patients or patients affected by various oxidative stresses, for example, diabetes and diabetic complications. To test this hypothesis, the bioactivities of FBG in diabetic and obese mice as well as the antioxidant activity in vitro were examined. After 91 days of continuous HFD supply, the mice showed marked obesity, hyperglycemia, hyperlipemia, and liver and kidney damages. Black garlic and all 3 different doses of FBG showed favorable hepatoprotective, nephroprotective, hypolipidemic, and antiobesity effects compared with the HFD control, but no hypoglycemic effects. In particular, more favorable bioactivity against all 4 HFD-induced diabetic complications was detected in the FBG-treated groups compared with the group given equivalent doses of BG. These findings suggest that the bioactivities of BG can be improved by yeast fermentation.