Hongmei Chang,Siqi Zhao,Yuzhu Lei,Yunhua Hu,Yizhong Yan,Guanling Song
Titanium dioxide nanoparticles (nano-TiO 2 ) can cause a reduction in sperm counts, and lactate production in Sertoli cells plays a key role in spermatogenesis. The aim of this study was to evaluate the effect of nano-TiO 2 on lactate production in mouse Sertoli cell line (TM4 cells) and to investigate whether the effect is mediated through the PI3K/AKT/HIF-1α pathway. After TM4 cells were treated with different concentrations of nano-TiO 2 for 48 h, cell viability, contents of glucose and lactate, and the expression levels of GLUT3 and key enzymes (HK1, HK2, PFKM, ENO1, LDH) during lactate production were detected. PI3K/AKT/HIF-1α pathway proteins were measured. In addition, PI3K agonist (IGF-1) was added to explore whether nano-TiO 2 regulates HIF-1α through PI3K/AKT pathway, thereby affecting the production of lactate in TM4 cells. The results showed that nano-TiO 2 significantly inhibited TM4 cell viability, increased glucose content, decreased lactate content, and downregulated the expression levels of GLUT3 and key enzymes during lactate production. Meanwhile, nano-TiO 2 decreased the expression of PI3K/AKT pathway phosphorylated proteins and HIF-1α, and IGF attenuated this effect of nano-TiO 2 . Collectively, nano-TiO 2 downregulated the expression level of proteins and enzymes related to lactate production in TM4 cells by inhibiting PI3K/AKT/HIF-1α pathway, resulting in the decrease of lactate production in TM4 cells.
Type 2 diabetes (T2D) with high morbidity and mortality is characterized by abnormal glucose and lipid metabolism due in part to insulin resistance in liver, which lead to elevated hyperglycemia and hyperlipidemia. This study sough to explore the effects of corosolic acid (CA) in different T2D models and explored the underlying mechanism. Separated from Eriobotrya japonica leaves, CA purity was above 95% measured by a HPLC method. Compared with cAMP and DEX induced T2D HepG2 model, CA significantly stimulated glucose consumption and improved glycogen accumulation by inhibiting PEPCK mRNA expression. And in cAMP and DEX induced T2D zebrafish model, CA reduced glycogen degradation and increased glucose consumption by regulating some key enzymes in carbon metabolism including GLUT1, GLUT2, GLUT3, LDHA, LDHB, GP, G6Pase, GYS1, and PFKFB3. In addition, insulin receptor signals were also involved in CA-regulated hypoglycemic action. Furthermore, in STZ-induced T2D rat model, compared with diabetic control groups, CA remarkably downregulated the levels of serum lipid, blood glucose, ICAM-1, malonaldehyde and insulin resistance index, while upregulated SOD activity and impaired glucose tolerance. In a conclusion, CA can regulate glucose and lipid metabolic adaptation in T2D like HepG2, zebrafish and rat models partly through reducing inflammation and oxidative stress and suppressing PEPCK .
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