Role of TFEB-autophagy lysosomal pathway in palmitic acid induced renal tubular epithelial cell injury.

Lysosomal dysfunction and impaired autophagic flux are involved in the pathogenesis of lipotoxicity in the kidney. Here, we investigated the role of transcription factor EB (TFEB), a master regulator of autophagy-lysosomal pathway, in palmitic acid induced renal tubular epithelial cells injury. We examined lipid accumulation, autophagic flux, expression of Ps211-TFEB, and nuclear translocation of TFEB in HK-2 cells overloaded with palmitic acid (PA). By utilizing immunohistochemistry, we detected TFEB expression in renal biopsy tissues from patients with diabetic nephropathy and normal renal tissue adjacent to surgically removed renal carcinoma (controls), as well as kidney tissues from rat fed with high-fat diet (HFD) and low-fat diet (LFD). We found significant lipid accumulation, increased apoptosis, accompanied with elevated Ps211-TFEB, decreased nuclear TFEB, reduced lysosome biogenesis and insufficient autophagy in HK-2 cells treated with PA. Kidney tissues from patients with diabetic nephropathy had lower nuclear and total levels of TFEB than that in control kidney tissues. Level of renal nuclear TFEB in HFD rats was also lower than that in LFD rats. Exogenous overexpression of TFEB increased the nuclear TFEB level in HK-2 cells treated with PA, promoted lysosomal biogenesis, improved autophagic flux, reduced lipid accumulation and apoptosis. Our results collectively indicate that PA is a strong inducer for TFEB phosphorylation modification at ser211 accompanied with lower nuclear translocation of TFEB. Impairment of TFEB-mediated lysosomal biogenesis and function by palmitic acid may lead to insufficient autophagy and promote HK-2 cells injury.

Study on intervention action of total flavonoids from Ilex Pubescens Radix on animal models of cerebral ischemic tolerance with blood stasis / 中国中药杂志

The mice models of blood stasis were established by injecting dexamethasone into the intramuscular of side the thigh for successive 15 days, and giving related drugs via an intragastric administration. Firstly, the method of blocking the bilateral common carotid artery (CCA) was used for 10 minutes, and then perfusion restore for 5 days. Secondly, the method of CCA was used for 30 minutes, and then reperfusion for 24 hours. The whole blood viscosity and plasma viscosity, the activity of NOS and ATPase and the level of NOS, and the content of Glu in the ischemic brain were measured. The morphological changes of brain tissue were observed by eosin (HE) staining technique. The results showed that compared with IPC model group the large doses of the flavonoids could reduce the viscosity of whole blood significantly (P<0.01). The small and medium doses of flavonoids could reduce the whole blood viscosity low-shear obviously (P<0.01). The medium doses of flavonoids could reduce the midst-shear obviously (P<0.05). The large and medium dose of flavonoids could significantly improve the ATP activity (P<0.01). The medium dose of flavonoids could improve the Na⁺-K⁺-ATPase activity significantly (P<0.01). The small dose of flavonoids could improve the Na⁺-K⁺-ATPase activity obviously (P<0.05). The large doses of flavonoids could reduce the content of gluin the ischemic brain significantly (P<0.01). And the others does of flavonoids could reduce the content of gluin the ischemic brain obviously (P<0.05). The large doses of flavonoids could reduce the activity of TNOS and iNOS significantly (P<0.01). The medium doses of flavonoids could reduce the activity of TNOS and iNOS obviously (P<0.05). The small doses of flavonoids could reduce the activity of iNOS obviously (P<0.05). Total flavonoids could obviously or significantly decrease the whole blood viscosity, the activity of NOS and the content of gluin the ischemic brain, increase the activity of ATPase significantly or obviously, could significantly relieve the degree of pathological injury of brain tissue of animal models.