Guangrong Zhou

Insulin resistance caused by the overexpression of protein tyrosine phosphatase 1 B (PTP1B) as well as the dephosphorylation of its target is one of the main causes of type 2 diabetes (T2D). A newly discovered proteoglycan, Fudan-Yueyang Ganoderma lucidum (FYGL) extracted from Ganoderma lucidum, was first reported to be capable of competitively inhibiting PTP1B activity in vitro in our previous work. In the present study, we sought to reveal the mechanism of PTP1B inhibition by FYGL at the animal and cellular levels. We found that FYGL can decrease blood glucose, reduce body weight and ameliorate insulin resistance in ob/ob mice. Decrease of PTP1B expression and increase of the phosphorylation of PTP1B targets in the insulin signaling pathway of skeletal muscles were observed. In order to clearly reveal the underlying mechanism of the hypoglycemic effect caused by FYGL, we further investigated the effects of FYGL on the PTP1B-involved insulin signaling pathway in rat myoblast L6 cells. We demonstrated that FYGL had excellent cell permeability by using a confocal laser scanning microscope and a flow cytometer. We found that FYGL had a positive effect on insulin-stimulated glucose uptake by using the 2-deoxyglucose (2-DG) method. FYGL could inhibit PTP1B expression at the mRNA level, phosphorylating insulin receptor substrate-1 (IRS1), as well as activating phosphatidylinositol-3 kinase (PI3K) and protein kinase B (Akt). Finally, FYGL increased the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and consequently up-regulated the expression of glucose transporter type 4 (GLUT4), promoting GLUT4 transportation to the plasma membrane in PTP1B-transfected L6 cells. Our study provides theoretical evidence for FYGL to be potentially used in T2D management.

The cell division cycle associated 5(CDCA5) was reported to be associated with progression of several human cancers, however, its clinical significance and biological role still remain unknown in gastric cancer(GC). By analyzing The Cancer Genome Atlas(TCGA), we found CDCA5 was significantly upregulated in GC tissues compared to adjacent normal tissues. Tissue microarray(TMA) indicated upregulation of CDCA5 was significantly correlated with more advanced clinicopathological features, and acts as an independent risk factor for worse overall survival(OS) in GC patients. Moreover, silence of CDCA5 suppresses proliferation of GC cells by inducing G1-phase arrest via downregulating Cyclin E1(CCNE1). Our results demonstrate upregulation of CDCA5 promotes GC malignant progression, which may offer a potential prognostic and therapeutic strategy.

Neurodegenerative diseases involve the disorder of protein folding in which normally soluble proteins are deposited as abnormally insoluble fibrils that disrupt tissue structure and cause disease. Aluminum ion, Al(III), is known to induce formation of the insoluble β-sheet-rich fibrils, while curcumin is considered capable of binding both metal ions and neurodegenerative disease-related proteins. In the present work, silk fibroin (SF) which have essential and sufficient amino acid sequences for the protein fibrillation on nucleation-dependent conformation transition mechanism similar to that for the fibrillation of neurodegenerative proteins, was used as a model protein to reveal the influence of curcumin on Al(III)-induced conformation transition of proteins. It was demonstrated that Al(III) could induce the conformation of SF into β-sheet, while curcumin could inhibit the event. In particular, Al(III)–curcumin complexes formed at [Al(III)]/[curcumin] ratios from 1 : 1 to 1 : 2 could reverse the conformation of SF from β-sheet into random coil. These findings would be of revelatory significance for developing an efficient approach inhibiting the fibrillation of neurodegenerative proteins.