Farnesoid X receptor (FXR) inhibits coagulation process via inducing hepatic antithrombin III expression in mice / 生理学报

Farnesoid X receptor (FXR) has been identified as an inhibitor of platelet function and an inducer of fibrinogen protein complex. However, the regulatory mechanism of FXR in hemostatic system remains incompletely understood. In this study, we aimed to investigate the functions of FXR in regulating antithrombin III (AT III). C57BL/6 mice and FXR knockout (FXR KO) mice were treated with or without GW4064 (30 mg/kg per day). FXR activation significantly prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT), lowered activity of activated factor X (FXa) and concentrations of thrombin-antithrombin complex (TAT) and activated factor II (FIIa), and increased level of AT III, whereas all of these effects were markedly reversed in FXR KO mice. In vivo, hepatic AT III mRNA and protein expression levels were up-regulated in wild-type mice after FXR activation, but down-regulated in FXR KO mice. In vitro study showed that FXR activation induced, while FXR knockdown inhibited, AT III expression in mouse primary hepatocytes. The luciferase assay and ChIP assay revealed that FXR can bind to the promoter region of AT III gene where FXR activation increased AT III transcription. These results suggest FXR activation inhibits coagulation process via inducing hepatic AT III expression in mice. The present study reveals a new role of FXR in hemostatic homeostasis and indicates that FXR might act as a potential therapeutic target for diseases related to hypercoagulation.

Positive Association of Human SHC3 Gene with Schizophrenia in a Northeast Chinese Han Population

Objective@#Schizophrenia is one of the most devastating neuropsychiatric disorders. Genetic epidemiological studies have confirmed that schizophrenia is a genetic disease. Genes promoting neurodevelopment may be potential candidates for schizophrenia. As an adaptor linking a number of tyrosine kinase receptors in multiple intracellular signaling cascades, Src homology 2 domain containing transforming protein 3 (SHC3) is a member of the Shc-like adaptor protein family, and expressed predominantly in the mature neurons of the central nervous system (CNS). In the present study, we aimed to investigate the association of SHC3 and schizophrenia. @*Methods@#An independent case-control association study was performed in a sample including 710 schizophrenia patients and 1314 healthy controls from a Northeast Chinese Han population. @*Results@#The allelic and genotypic association analyses showed that four SNPs in SHC3 significantly associated with schizophrenia (rs2316280, rs4877041, rs944485 and rs7021743). The haplotype composing of these four SNPs also showed significantly individual and global association with schizophrenia. @*Conclusion@#Our present results suggest SHC3 as a susceptibility gene for schizophrenia.

Role of pregnane X receptor (PXR) in endobiotic metabolism / 生理学报

As a member of the nuclear receptor superfamily, the pregnane X receptor (PXR) is a ligand-activated transcription factor. PXR is highly expressed in liver and intestinal tissues, and also found in other tissues and organs, such as stomach and kidney. After heterodimerization with retinoid X receptor (RXR), PXR recruits numerous co-activating factors, and binds to specific DNA response elements to perform transcriptional regulation of the downstream target genes. As an acknowledged receptor for xenobiotics, PXR was initially considered as a nuclear receptor regulating drug metabolizing enzymes and transporters. However, nowadays, PXR has also been recognized as an important endobiotic receptor. Recent studies have shown that PXR activation can regulate glucose metabolism, lipid metabolism, steroid endocrine homeostasis, detoxification of cholic acid and bilirubin, bone mineral balance, and immune inflammation in vivo. This review focuses on the role of PXR in metabolism of endogenous substances.