Talin1 regulates glucose metabolism and endometrial receptivity via GLUT-4 in patients with polycystic ovary syndrome and insulin resistance.

Objectives: Talin1 is a cytoskeletal protein and is localized between cells and the extracellular matrix. This study aimed to investigate the mechanism by which Talin1 affects glucose metabolism and endometrial receptivity via glucose transporter proteins-4 (GLUT-4) in patients with polycystic ovary syndrome (PCOS) and insulin resistance (IR). Methods: We examined the expression of Talin1 and GLUT4 in the receptive endometrium of PCOS-IR and control patients. GLUT4 expression was examined after silencing and overexpression of Talin1 in Ishikawa cells. We validated the interaction between Talin1 and GLUT-4 proteins using a co-immunoprecipitation (Co-IP) assay. After successfully establishing the C57BL/6j mouse model of PCOS-IR, the expression of Talin1 and GLUT-4 were examined in PCOS-IR and control mice. The effect of Talin1 on embryo implantation and the number of live births in mice were examined. Results: Our study found low expression of Talin1 and GLUT-4 in the receptive endometrium of PCOS-IR patients compared to that in control patients (p < 0.01). The level of GLUT-4 expression decreased after silencing Talin1 in Ishikawa cells and increased after overexpression of Talin1. Co-IP results showed that Talin1 interacts with GLUT-4 protein. We successfully established a PCOS-IR C57BL/6j mouse model and found that Talin1 and GLUT-4 expression in the receptive endometrium of PCOS-IR mice were lower than that in control mice (p < 0.05). In vivo experiments confirmed that the knockdown of Talin1 affects embryo implantation (p < 0.05) and live birth rate in mice (p < 0.01). Conclusions: Talin1 and GLUT-4 expression were decreased in the endometrium of PCOS-IR patients, and Talin1 may affect glucose metabolism and endometrial receptivity through GLUT4.

Far-infrared protects vascular endothelial cells from advanced glycation end products-induced injury via PLZF-mediated autophagy in diabetic mice.

The accumulation of advanced glycation end products (AGEs) in diabetic patients induces vascular endothelial injury. Promyelocytic leukemia zinc finger protein (PLZF) is a transcription factor that can be activated by low-temperature far-infrared (FIR) irradiation to exert beneficial effects on the vascular endothelium. In the present study, we investigated the influence of FIR-induced PLZF activation on AGE-induced endothelial injury both in vitro and in vivo. FIR irradiation inhibited AGE-induced apoptosis in human umbilical vein endothelial cells (HUVECs). PLZF activation increased the expression of phosphatidylinositol-3 kinases (PI3K), which are important kinases in the autophagic signaling pathway. FIR-induced PLZF activation led to autophagy in HUVEC, which was mediated through the upregulation of PI3K. Immunofluorescence staining showed that AGEs were engulfed by HUVECs and localized to lysosomes. FIR-induced autophagy promoted AGEs degradation in HUVECs. In nicotinamide/streptozotocin-induced diabetic mice, FIR therapy reduced serum AGEs and AGEs deposition at the vascular endothelium. FIR therapy also reduced diabetes-induced inflammatory markers in the vascular endothelium and improved vascular endothelial function. These protective effects of FIR therapy were not found in PLZF-knockout mice. Our data suggest that FIR-induced PLZF activation in vascular endothelial cells protects the vascular endothelium in diabetic mice from AGE-induced injury.