The ISG15/USP18 ubiquitin-like pathway (ISGylation system) in hepatitis C virus infection and resistance to interferon therapy

The ISG15/USP18 pathway modulates cellular functions and is important for the host innate immune response to chronic viral infections such as Hepatitis C Virus (HCV). Interferon stimulated gene 15 (ISG15) was the first ubiquitin-like protein modifier identified. As in ubiquitination, ISG15 conjugates to target proteins (ISGylation) through the sequential enzymatic action of activating E1, conjugating E2, and ligating E3 enzymes. ISGylation modulates signal transduction pathways and host anti-viral response. The ISGylation process is reversible through the action of an ISG15 protease, USP18. Ubiquitin-like specific protease 18 (USP18) has functions that are both ISG15-dependent and ISG15-independent; the importance of the ISG15/USP18 pathway to chronic HCV infection is illustrated by the consistent finding of increased levels of ISG15 and USP18 in the liver tissue of patients who do not respond to interferon-based treatments. Mechanistically, HCV seems to exploit the ISG15/USP18 pathway to promote viral replication and evade innate anti-viral immune responses.     

Discovery of new thienopyrimidine derivatives as potent and orally efficacious phosphoinositide 3-kinase inhibitors

A series of new thienopyrimidine derivatives has been discovered as potent PI3K inhibitors. The systematic SAR studies for these analogues are described. Among them, 8a and 9a exhibit nanomolar enzymatic potencies and sub-micromolar cellular anti-proliferative activities. 8a displays favorable pharmacokinetic profiles, while 9a easily undergoes deacetylation to yield a major metabolite 8a. Furthermore, 8a and 9a potently inhibit tumor growth in a dose-dependent manner in the NCI-H460 xenograft model with an acceptable safety profile.     

Upregulation of miR-582-5p regulates cell proliferation and apoptosis by targeting AKT3 in human endometrial carcinoma

The human endometrial carcinoma is one of the most common female malignancies, and there is an urgent requirement to explore new therapeutic strategies. There is accumulating evidence that microRNAs (miRNAs) can serve as potential diagnostic and prognostic biomarkers for various types of cancer, but the significance of miR-582-5p still remains largely unknown in the endometrial carcinoma. The aims of this study were to understand and identify the influence of miR-582-5p on the proliferation and apoptosis of human endometrial carcinoma and its relevant mechanism. First, quantitative real-time PCR (qRT-PCR) was used to detect miR-582-5p and AKT3 expression in human tissue samples and cells. Then, CyQuant assay and 2D colony assay were employed to evaluate cell proliferation. Western blotting was used to determine protein expression. Subsequently, the luciferase reporter assay was used to identify the target of miR-582-5p. Finally, Annexin V assay was used to detect cell apoptosis. We found that miR-582-5p expression was significantly decreased in human endometrial carcinoma tissues, and miR-582-5p upregulation in human endometrial carcinoma cells inhibit cell proliferation and promote apoptosis. Moreover, AKT3 was validated as a target of miR-582-5p and AKT3 expression was inversely correlated with miR-582-5p expression. Besides, AKT3 upregulation efficiently abrogates the effect of miR-582-5p on the cells. These results demonstrated that miR-582-5p regulates cell proliferation and apoptosis in human endometrial carcinoma via AKT3. Thus, miR-582-5p represents a potential therapeutic target in human endometrial carcinoma meriting further investigation.     

AIDA Selectively Mediates Downregulation of Fat Synthesis Enzymes by ERAD to Retard Intestinal Fat Absorption and Prevent Obesity

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Mitochondrial unfolded protein response gene Clpp is required to maintain ovarian follicular reserve during aging,for oocyte competence,and development of pre‐implantation embryos

Caseinolytic peptidase P mediates degradation of unfolded mitochondrial proteins and activates mitochondrial unfolded protein response (mtUPR) to maintain protein homeostasis. Clpp^?/? female mice generate a lower number of mature oocytes and two‐cell embryos, and no blastocysts. Clpp^?/? oocytes have smaller mitochondria, with lower aspect ratio (length/width), and decreased expression of genes that promote fusion. A 4‐fold increase in atretic follicles at 3 months, and reduced number of primordial follicles at 6–12 months are observed in Clpp^?/? ovaries. This is associated with upregulation of p‐S6, p‐S6K, p‐4EBP1 and p‐AKT473, p‐mTOR2481 consistent with mTORC1 and mTORC2 activation, respectively, and Clpp^?/? oocyte competence is partially rescued by mTOR inhibitor rapamycin. Our findings demonstrate that CLPP is required for oocyte and embryo development and oocyte mitochondrial function and dynamics. Absence of CLPP results in mTOR pathway activation, and accelerated depletion of ovarian follicular reserve.