METABOLIC DISORDERS, such as PCOS (polycystic ovary syndrome) and T2DM (type 2 diabetes mellitus), are reported to be associated with high miscarriage rates, decreased pregnancy rates, and low live birth rates [1]. PCOS and T2DM are characterized by hyperinsulinemia [2]. PCOS is an endocrine and metabolic disorder with a prevalence ranging from 5 to 13% in women of reproductive age. Moreover, PCOS is often accompanied by menstrual dysfunction, anovulaHigh insulin impaired ovarian function in early pregnant mice and the role of autophagy in this process Abstract. Metabolic disorders, such as PCOS (polycystic ovarian syndrome) and T2DM (type 2 diabetes mellitus), are associated with menstrual dysfunction, anovulation, infertility, and early pregnancy loss. Ovarian dysfunction is not only related to low pregnancy rates but also to the increased risk of miscarriage. Women with PCOS or T2DM, characterized by hyperinsulinemia, commonly experience ovarian dysfunction. In this study, we first explored whether high insulin levels directly affected ovarian functioning during embryo implantation. Mice in the insulin-treated group were given a subcutaneous injection of human recombinant insulin. After insulin treatment, serum levels of E2 (estrogen), PROG (progesterone), LH (luteinizing hormone), and FSH (follicle-stimulating hormone) were obviously lower, and there was a significant decrement of ovarian GDF9 (growth differentiation factor 9) mRNA. H&E (hematoxylin and eosin) staining showed a greater number of immature follicles and less luteinization in the insulin group. Further autophagy was studied in this process. A significant increase of P62 (SQSTM1/Sequestosome1) and a decrease of Cathepsin B, BECN1 (Beclin 1), and ULK1 (Unc-51-like kinase 1) mRNA in ovary was found in the insulin group. Western blot analysis showed that the expressions of LC3 (microtubule-associated protein 1 light chain 3), BECN1, and Cathepsin B proteins in ovaries from insulin group were obviously reduced, while P62 proteins were significantly increased. All these results illustrated that insulin could directly impair ovarian function during embryo implantation and the imbalance of ovarian autophagy due to insulin. Autophagy could enhance the impaired ovarian function results from insulin.

The potential benefit of nutrient starvation in the prevention and treatment of cancer is presently under consideration. Resveratrol (RV), a dietary polyphenol acting as a protein (caloric) restriction mimetic, could substitute for amino acid starvation. The effects of starvation and of caloric restriction are mediated, among others, by autophagy, a process that contributes to cell homeostasis by promoting the lysosomal degradation of damaged and redundant self-constituents. Up-regulation of autophagy favors cell survival under nutrient shortage situation, and may drive cancer cells into a non-replicative, dormant state. Both RV and amino acid starvation effectively induced the aminoacid response and autophagy. These processes were associated with inhibition of the mTOR pathway and disruption of the BECLIN1-BCL-2 complex. The number of transcripts positively impinging on the autophagy pathway was higher in RV-treated than in starved cancer cells. Consistent with our data, it appears that RV treatment is more effective than and can substitute for starvation for inducing autophagy in cancer cells. The present findings are clinically relevant because of the potential therapeutic implications.

Death receptors of TNFSF10/TRAIL (tumor necrosis factor superfamily member 10) contribute to immune surveillance against virus-infected or transformed cells by promoting apoptosis. Many viruses evade antiviral immunity by modulating TNFSF10 receptor signaling, leading to persistent infection. Here, we report that hepatitis B virus (HBV) X protein (HBx) restricts TNFSF10 receptor signaling via macroautophagy/autophagymediated degradation of TNFRSF10B/DR5, a TNFSF10 death receptor, and thus permits survival of virusinfected cells. We demonstrate that the expression of the TNFRSF10B protein is dramatically reduced both in liver tissues of chronic hepatitis B patients and in cell lines transfected with HBV or HBx. HBx-mediated downregulation of TNFRSF10B is caused by the lysosomal, but not proteasomal, degradation pathway. Immunoblotting analysis of LC3B and SQSTM1, and microscopy analysis of tandem-fluorescence-tagged LC3B revealed that HBx promotes complete autophagy. Inhibition of autophagy with a pharmacological inhibitor and LC3B knockdown revealed that HBx-induced autophagy is crucial for TNFRSF10B degradation. Immunoprecipitation and GST affinity isolation assays showed that HBx directly interacts with TNFRSF10B and recruits it to phagophores, the precursors to autophagosomes. We confirmed that autophagy activation is related to the downregulation of the TNFRSF10B protein in liver tissues of chronic hepatitis B patients. Inhibition of autophagy enhanced the susceptibility of HBx-infected hepatocytes to TNFSF10. These results identify the dual function of HBx in TNFRSF10B degradation: HBx plays a role as an autophagy receptor-like molecule, which promotes the association of TNFRSF10B with LC3B; HBx is also an autophagy inducer. Our data suggest a molecular mechanism for HBV evasion from TNFSF10-mediated antiviral immunity, which may contribute to chronic HBV infection.