Elucidation of SIRT-1/PGC-1α-associated mitochondrial dysfunction and autophagy in nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) can lead to chronic liver diseases associated with mitochondrial damages. However, the exact mechanisms involved in the etiology of the disease are not clear. METHODS: To gain new insights, the changes affecting sirtuin 1 (SIRT-1) during liver fat accumulation was investigated in a NAFLD mouse model. In addition, the in vitro research investigated the regulation operated by SIRT-1 on mitochondrial structures, biogenesis, functions, and autophagy. RESULTS: In mice NAFLD, high-fat-diet (HFD) increased body weight gain, upregulated serum total cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, blood glucose, insulin levels, and liver malondialdehyde, and decreased liver superoxide dismutase activity. In liver, the levels of SIRT-1 and peroxisome proliferator-activated receptor-gamma coactivator -1α (PGC-1α) decreased. The expression of peroxisome proliferator-activated receptor-α and Beclin-1 proteins was also reduced, while p62/SQSTM1 expression increased. These results demonstrated SIRT-1 impairment in mouse NAFLD. In a well-established NAFLD cell model, exposure of the HepG2 hepatocyte cell line to oleic acid (OA) for 48 h caused viability reduction, apoptosis, lipid accumulation, and reactive oxygen species production. Disturbance of SIRT-1 expression affected mitochondria. Pre-treatment with Tenovin-6, a SIRT-1 inhibitor, aggravated the effect of OA on hepG2, while this effect was reversed by CAY10602, a SIRT-1 activator. Further investigation demonstrated that SIRT-1 activity was involved in mitochondrial biogenesis through PGC-1α and participated to the balance of autophagy regulatory proteins. CONCLUSION: In conclusion, in high-fat conditions, SIRT-1 regulates multiple cellular properties by influencing on mitochondrial physiology and lipid autophagy via the PGC-1α pathway. The SIRT-1/PGC-1α pathway could be targeted to develop new NAFLD therapeutic strategies.

Proximity hybridization triggered hybridization chain reaction for label-free electrochemical homogeneous aptasensors.

A label-free homogeneous electrochemical aptasensor was developed for detection of thrombin based on proximity hybridization triggered hybridization chain reaction induced G-quadruplex formation. Thrombin promoted the formation of a complex via the proximity hybridization of the aptamer DNA strands, which unfolded the molecular beacon, the stem part of molecular beacon as a primer to initiate the hybridization chain reaction process. Thus, with the electrochemical indicator hemin selectively intercalated into the multiple G-quadruplexes, a significant electrochemical signal drop is observed, which is dependent on the concentration of the target thrombin. Thus, using this"signal-off" mode, label-free homogeneous electrochemical strategy for sensitive thrombin assay with a detection limit of 44 fM is realized. Furthermore, this method also exhibits additional advantages of simplicity and low cost, since both expensive labeling and sophisticated probe immobilization processes are avoided. Its high sensitivity, acceptable accuracy, and satisfactory versatility of analytes led to various applications in bioanalysis.

Phytanoyl-CoA 2-Hydroxylase-Interacting Protein-Like Gene Is a Therapeutic Target Gene for Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is the most common primary CNS cancer and has a poor prognosis. This study searched for significant genes and the mechanisms involved in GBM. We used the Gene Expression Omnibus (GEO) to test the WHO normal and IV glioma database, used R tool to identify the significant gene, and finally, combined these with The Cancer Genome Atlas (TCGA) to verify the significant genes. Subsequently, we explored the biological mechanisms involved. Phytanoyl-CoA 2-hydroxylase-interacting protein-like gene (PHYHIPL) is downregulated in grade IV glioma (GBM). The downregulation of PHYHIPL in GBM is accompanied by poor overall survival in the TCGA database, which indicates that PHYHIPL is a protection gene in GBM development. Bioinformatics analysis shows that the poor prognosis with downregulated PHYHIPL may be the result of the TNF signaling pathway and the IL-17 signaling pathway, but good prognosis accompanied by upregulated PHYHIPL may be the result of retrograde endocannabinoid signaling and the cAMP signaling pathway. Protein-protein interactions (PPI) net indicated that PHYHIPL may play a vital role in cell metabolism, and we hypothesize that the downregulation mechanism may be the result of mutations of the ß-catenin gene and the endogenous siRNA, as shown in previous studies. PHYHIPL may be a target gene for the treatment and prognosis of GBM.

GSK-3ß Promotes Cell Migration and Inhibits Autophagy by Mediating the AMPK Pathway in Breast Cancer.

GSK-3ß is a versatile protein kinase participating in many reactions. Currently, there is insufficient understanding of its influence on breast cancer (BC). In order to explore its influence on migration and invasion in BC, we investigated its expression in BC cell lines using qRT-PCR and Western blot (WB). Immunohistochemistry (IHC) was used to examine the potential of GSK-3ß to predict clinical outcome in BC patients. GSK-3ß knockdown was achieved using an shRNA plasmid vector in T47D cells. Our research explored the biological reactions and downstream pathways involved. We found excessive GSK-3ß expression in BC tissues, which was correlated with worse clinicopathological parameters and clinical outcome. Progression of BC was suppressed by GSK-3ß knockdown. Furthermore, suppression of GSK-3ß function led to a noticeable decrease in ATP generation, and this was associated with stimulation of AMP-activated protein kinase (AMPK) in T47D cells. Activation of AMPK, a typical sign of autophagy stimulation, was triggered after suppression of GSK-3ß function, in parallel with increased generation of LC3 II. Our findings therefore indicate that GSK-3ß participates in regulation of migration as well as stimulation of autophagy via mediating activation of the AMPK pathway. This suggests that GSK-3ß has potential as a predictor of clinical outcome and as a target for BC therapy.