Autophagy dysfunction contributes to NLRP1 inflammasome-linked depressive-like behaviors in mice.

BACKGROUND: Major depressive disorder (MDD) is a common but severe psychiatric illness characterized by depressive mood and diminished interest. Both nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 1 (NLRP1) inflammasome and autophagy have been reported to implicate in the pathological processes of depression. However, the mechanistic interplay between NLRP1 inflammasome, autophagy, and depression is still poorly known. METHODS: Animal model of depression was established by chronic social defeat stress (CSDS). Depressive-like behaviors were determined by social interaction test (SIT), sucrose preference test (SPT), open field test (OFT), forced swim test (FST), and tail-suspension test (TST). The protein expression levels of NLRP1 inflammasome complexes, pro-inflammatory cytokines, phosphorylated-phosphatidylinositol 3-kinase (p-PI3K)/PI3K, phosphorylated-AKT (p-AKT)/AKT, phosphorylated-mechanistic target of rapamycin (p-mTOR)/mTOR, brain-derived neurotrophic factor (BDNF), phosphorylated-tyrosine kinase receptor B (p-TrkB)/TrkB, Bcl-2-associated X protein (Bax)/B-cell lymphoma-2 (Bcl2) and cleaved cysteinyl aspartate-specific proteinase-3 (caspase-3) were examined by western blotting. The mRNA expression levels of pro-inflammatory cytokines were tested by quantitative real-time PCR. The interaction between proteins was detected by immunofluorescence and coimmunoprecipitation. Neuronal injury was assessed by Nissl staining. The autophagosomes were visualized by transmission electron microscopy. Nlrp1a knockdown was performed using an adeno-associated virus (AAV) vector containing Nlrp1a-shRNA-eGFP infusion. RESULTS: CSDS exposure caused a bidirectional change in hippocampal autophagy function, which was activated in the initial period but impaired at the later stage. In addition, CSDS exposure increased the expression levels of hippocampal NLRP1 inflammasome complexes, pro-inflammatory cytokines, p-PI3K, p-AKT and p-mTOR in a time-dependent manner. Interestingly, NLRP1 is immunoprecipitated with mTOR but not PI3K/AKT and CSDS exposure facilitated the immunoprecipitation between them. Hippocampal Nlrp1a knockdown inhibited the activity of PI3K/AKT/mTOR signaling, rescued the impaired autophagy and ameliorated depressive-like behavior induced by CSDS. In addition, rapamycin, an autophagy inducer, abolished NLRP1 inflammasome-driven inflammatory reactions, alleviated depressive-like behavior and exerted a neuroprotective effect. CONCLUSIONS: Autophagy dysfunction contributes to NLRP1 inflammasome-linked depressive-like behavior in mice and the regulation of autophagy could be a valuable therapeutic strategy for the management of depression.

[Difference of lipid-lowering efficacy of "Xinjianqu" before and after fermentation and its mechanism based on LKB1-AMPK pathway and 16S rDNA sequencing technology].

On the basis of establishing the prescription of Xinjianqu and clarifying the increase of the lipid-lowering active ingredients of Xinjianqu by fermentation, this paper further compared the differences in the lipid-lowering effects of Xinjianqu before and after fermentation, and studied the mechanism of Xinjianqu in the treatment of hyperlipidemia. Seventy SD rats were randomly divided into seven groups, including normal group, model group, positive drug simvastatin group(0.02 g·kg~(-1)), and low-dose and high-dose Xinjianqu groups before and after fermentation(1.6 g·kg~(-1) and 8 g·kg~(-1)), with ten rats in each group. Rats in each group were given high-fat diet continuously for six weeks to establish the model of hyperlipidemia(HLP). After successful modeling, the rats were given high-fat diet and gavaged by the corresponding drugs for six weeks, once a day, to compare the effects of Xinjianqu on the body mass, liver coefficient, and small intestine propulsion rate of rats with HLP before and after fermentation. The effects of Xinjianqu before and after fermentation on total cholesterol(TC), triacylglyceride(TG), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), alanine aminotransferase(ALT), aspartate aminotransferase(AST), blood urea nitrogen(BUN), creatinine(Cr), motilin(MTL), gastrin(GAS), and the Na~+-K~+-ATPase levels were determined by enzyme-linked immunosorbent assay(ELISA). The effects of Xinjianqu on liver morphology of rats with HLP were investigated by hematoxylin-eosin(HE) staining and oil red O fat staining. The effects of Xinjianqu on the protein expression of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK), phosphorylated AMPK(p-AMPK), liver kinase B1(LKB1), and 3-hydroxy-3-methylglutarate monoacyl coenzyme A reductase(HMGCR) in liver tissues were investigated by immunohistochemistry. The effects of Xinjianqu on the regulation of intestinal flora structure of rats with HLP were studied based on 16S rDNA high-throughput sequencing technology. The results showed that compared with those in the normal group, rats in the model group had significantly higher body mass and liver coefficient(P<0.01), significantly lower small intestine propulsion rate(P<0.01), significantly higher serum levels of TC, TG, LDL-C, ALT, AST, BUN, Cr, and AQP2(P<0.01), and significantly lower serum levels of HDL-C, MTL, GAS, Na~+-K~+-ATP levels(P<0.01). The protein expression of AMPK, p-AMPK, and LKB1 in the livers of rats in the model group was significantly decreased(P<0.01), and that of HMGCR was significantly increased(P<0.01). In addition, the observed＿otus, Shannon, and Chao1 indices were significantly decreased(P<0.05 or P<0.01) in rat fecal flora in the model group. Besides, in the model group, the relative abundance of Firmicutes was reduced, while that of Verrucomicrobia and Proteobacteria was increased, and the relative abundance of beneficial genera such as Ligilactobacillus and Lachnospiraceae＿NK4A136＿group was reduced. Compared with the model group, all Xinjianqu groups regulated the body mass, liver coefficient, and small intestine index of rats with HLP(P<0.05 or P<0.01), reduced the serum levels of TC, TG, LDL-C, ALT, AST, BUN, Cr, and AQP2, increased the serum levels of HDL-C, MTL, GAS, and Na~+-K~+-ATP, improved the liver morphology, and increased the protein expression gray value of AMPK, p-AMPK, and LKB1 in the liver of rats with HLP and decreased that of LKB1. Xinjianqu groups could regulate the intestinal flora structure of rats with HLP, increased observed＿otus, Shannon, Chao1 indices, and increased the relative abundance of Firmicutes, Ligilactobacillus(genus), Lachnospiraceae＿NK4A136＿group(genus). Besides, the high-dose Xinjianqu-fermented group had significant effects on body mass, liver coefficient, small intestine propulsion rate, and serum index levels of rats with HLP(P<0.01), and the effects were better than those of Xinjianqu groups before fermentation. The above results show that Xinjianqu can improve the blood lipid level, liver and kidney function, and gastrointestinal motility of rats with HLP, and the improvement effect of Xinjianqu on hyperlipidemia is significantly enhanced by fermentation. The mechanism may be related to AMPK, p-AMPK, LKB1, and HMGCR protein in the LKB1-AMPK pathway and the regulation of intestinal flora structure.

[Quality control of human chorionic gonadotrophin subunit dissociation].

Human chorionic gonadotrophin (hCG), a glycohormone widely used in treatment of infertility, is a heterodimer composed of an alpha- and a beta-subunit. The heterodimer could be dissociated during production and storage with an impact on its bioactivity. A CE-SDS method for quantitative analysis of hCG subunit dissociation was established in this study by optimization of a variety of method conditions including sample preparation buffer compositions, incubation temperature, separation voltage, and capillary temperature. This method was validated for good sensitivity, linearity, precision, and accuracy for both α- and ß-subunit. CE-SDS also showed much better precision and accuracy than SDS-PAGE. The method was successfully used in both recombinant hCG (r-hCG) produced by cell culture and hCG (u-hCG) derived from urine. The CE-SDS method was used in the study of hCG development and stability. Therefore, it is an useful tool for the quality control of hCG.