The Function and Mechanism of Enterovirus 71 (EV71) 3C Protease.

Enterovirus 71 (EV71) is the main pathogen of the hand, foot, and mouth disease. It was firstly isolated from sputum specimens of infants with central nervous system diseases in California in 1969, and has been repeatedly reported in various parts of the world, especially in the Asia-Pacific region. EV71 3C protein is a 183 amino acid cysteine protease that can cleave most structural and non-structural proteins of EV71. Based on the analysis and understanding of EV71 3C protease, it is helpful to study and treat diseases caused by EV71 virus infection. The EV71 3C protease promotes virus replication by cleaving EV71 synthesis or host proteins. Moreover, EV71 3C protease inhibits the innate immune system and causes apoptosis. At present, in order to deal with the damage caused by the EV71, it is urgent to develop antiviral drugs targeting 3C protease. This review will focus on the structure, function, and mechanism of EV71 3C protease.

Notch signalling regulates steroidogenesis in mouse ovarian granulosa cells.

The Notch signalling pathway in the mammalian ovary regulates granulosa cell proliferation. However, the effects of Notch signalling on steroidogenesis are unclear. In this study we cultured mouse ovarian granulosa cells from preantral follicles invitro and observed the effect of Notch signalling on steroidogenesis through overexpression, knockdown and inhibition of Notch signalling. Activation of Notch signalling decreased progesterone and oestrogen secretion. In contrast, inhibition of Notch signalling increased the production of progesterone and oestrogen. Expression of the genes for steroidogenic-related enzymes, including 3ß-hydroxysteroid dehydrogenase, p450 cholesterol side-chain cleavage enzyme and aromatase, was repressed after stimulation of Notch signalling. The expression of upstream transcription factors, including steroidogenic factor 1 (SF1), Wilms' tumour 1 (Wt1), GATA-binding protein 4 (Gata4) and Gata6, was also inhibited after stimulation of Notch signalling. Production of interleukin (IL)-6 was positively correlated with Notch signalling and negatively correlated with the expression of these transcription factors and enzymes. In conclusion, Notch signalling regulated progesterone and oestrogen secretion by affecting the expression of upstream transcription factors SF1, Wt1, Gata4 and Gata6, as well as downstream steroidogenic-related enzymes. IL-6, which may be regulated directly by Notch signalling, may contribute to this process. Our findings add to the understanding of the diverse functions of Notch signalling in the mammalian ovary.

Notch signaling inhibition induces G0/G1 arrest in murine Leydig cells.

As a highly evolutionarily conserved signaling pathway, Notch widely participates in cell-fate decisions and the development of various tissues and organs. In male reproduction, research on the Notch signaling pathway has mainly concentrated on germ cells and Sertoli cells. Leydig cells are the primary producers of testosterone and play important roles in spermatogenesis and maintaining secondary sexual characteristics. In this study, we used TM3 cells, a murine adult Leydig cell line, to investigate the expression profiles of Notch receptors and ligands and observe the effect of Notch signaling on the proliferation of TM3 cells. We found that Notch 1-3 and the ligands Dll-1 and Dll-4 were expressed in TM3 cells, Notch 1-3 and the ligand Dll-1 were expressed in testis interstitial Leydig cells, and Notch signaling inhibition suppressed the proliferation of TM3 cells and induced G0/G1 arrest. Inhibition of Notch signaling increased the expression of p21Waf1/Cip1 and p27. Overall, our results suggest that Notch inhibition suppresses the proliferation of TM3 cells and P21Waf1/Cip1 , and p27 may contribute to this process.

LncPrep + 96kb 2.2 kb Inhibits Estradiol Secretion From Granulosa Cells by Inducing EDF1 Translocation.

LncPrep + 96kb is a novel long non-coding RNA expressed in murine granulosa cells with two transcripts that are 2.2 and 2.8 kb in length. However, the potential roles of lncPrep + 96kb in granulosa cells remain poorly understood. In this study, we investigated the effect of the lncPrep + 96kb 2.2 kb transcript on granulosa cells through the overexpression and knockdown of lncPrep + 96kb 2.2 kb. We found that lncPrep + 96kb 2.2 kb inhibited aromatase expression and estradiol production. Endothelial differentiation-related factor 1 (EDF1) is an evolutionarily conserved transcriptional coactivator. We found that EDF1 knockdown inhibited aromatase expression and estradiol production. The RNA immunoprecipitation results also showed that lncPrep + 96kb 2.2 kb can bind to EDF1 and that overexpression of lncPrep + 96kb 2.2 kb induced the translocation of EDF1 from the nucleus to the cytoplasm. The CatRAPID signature revealed that the 1,979-2,077 and 603-690 nucleotide positions in lncPrep + 96kb 2.2 kb were potential binding sites for EDF1. We found that mutating the 1,979-2,077 site rescued the effects of lncPrep + 96kb 2.2 kb on aromatase expression and estradiol production. In conclusion, we are the first to report that specific expression of lncPrep + 96kb 2.2 kb in granulosa cells inhibits the production of estradiol by influencing the localization of EDF1 in granulosa cells. The 1,979-2,077 site of lncPrep + 96kb 2.2 kb contributes to the ability to bind to EDF1.