Neuron stem cell NLRP6 sustains hippocampal neurogenesis to resist stress-induced depression

Neurogenesis decline in hippocampal dentate gyrus (DG) participates in stress-induced depressive-like behaviors, but the underlying mechanism remains poorly understood. Here, we observed low-expression of NOD-like receptor family pyrin domain containing 6 (NLRP6) in hippocampus of stress-stimulated mice, being consistent with high corticosterone level. NLRP6 was found to be abundantly expressed in neural stem cells (NSCs) of DG. Both Nlrp6 knockout (Nlrp6-/-) and NSC-conditional Nlrp6 knockout (Nlrp6CKO) mice were susceptible to stress, being more likely to develop depressive-like behaviors. Interestingly, NLRP6 was required for NSC proliferation in sustaining hippocampal neurogenesis and reinforcing stress resilience during growing up. Nlrp6 deficiency promoted esophageal cancer-related gene 4 (ECRG4) expression and caused mitochondrial dysfunction. Corticosterone as a stress factor significantly down-regulated NLRP6 expression, damaged mitochondrial function and suppressed cell proliferation in NSCs, which were blocked by Nlrp6 overexpression. ECRG4 knockdown reversed corticosterone-induced NSC mitochondrial function and cell proliferation disorders. Pioglitazone, a well-known clinical drug, up-regulated NLRP6 expression to inhibit ECRG4 expression in its protection against corticosterone-induced NSC mitochondrial dysfunction and proliferation restriction. In conclusion, this study demonstrates that NLRP6 is essential to maintain mitochondrial homeostasis and proliferation in NSCs, and identifies NLRP6 as a promising therapeutic target for hippocampal neurogenesis decline linked to depression.

Effect and Mechanism of Intestinal Flora on Mucin 2 / 胃肠病学

Mucin 2 (MUC2) is a kind of heavily glycosylated protein secreted by intestinal goblet cells. As the main component of intestinal mucus, MUC2 plays an important role in preventing the pathogenic microorganism from invasion as well as in assisting the colonization of intestinal probiotics. Intestinal flora is involved in many physiological functions of the human body. It modulates the synthesis, secretion and degradation of MUC2 through different mechanisms to affect the quality and quantity of MUC2. This article reviewed the effect and mechanism of intestinal flora on MUC2.