Objective: To investigate the effects of abated microRNA-21 (miRNA-21) on phosphatase and tensin homologue on chromosome ten protein (PTEN) and PI3K/Akt/mTOR pathway, as well as their further influence on the autophagy in high glucose (HG, 25.0 mmol/L) induced rat glomerular mesangial cells. Methods: MiRNA-21 inhibitor and negative control were transfected by liposome 2000 into rat glomerular mesangial cells (HBZY-1). The cells were divided into normal glucose (5.5 mmol/L) group, normal glucose+negative control group, normal glucose+miRNA-21 inhibitor group, HG group, HG+negative control group and HG+miRNA-21 inhibitor group. Cell proliferation and hypertrophy were assayed by MTT and the ratio of total protein to cell number respectively. The miRNA-21 expression was detected using real time PCR. The expressions of PTEN/Akt/mTOR signaling signatures, autophagy-associated protein (p62 and LC3 Ⅱ) and collagen Ⅰ was detected by Western blotting and real time PCR. Autophagosomes were observed using electron microscopy. Results: Compared with those in normal glucose group, in HG group cells had hypertrophy and proliferation, up-regulated miRNA-21 expression, and down-regulated PTEN protein and mRNA expressions (all P<0.01). Also there were and up-regulated p-Akt, p-mTOR, p62 and collagen Ⅰ expression, and lower LC3 Ⅱ expression and autophagosomes (all P<0.01). Further, compared with those in HG group, cells hypertrophy and proliferation in HG+miRNA-21 inhibitor group were reduced, expressions of p-Akt, p-mTOR, p62 and collagen Ⅰ were down-regulated, while expressions of PTEN and LC3 Ⅱ and autophagosomes were up-regulated (all P<0.01). Conclusions MiRNA-21 inhibitor up-regulates PTEN expression, which inhibits the activation of Akt/mTOR signaling pathway, ameliorates cell hypertrophy, proliferation and enhances autophagy to reduce extracellular matrix accumulation.

Objective To investigate the effects of nuclear respiratory factor 1(NRF1)on mitochondrial and cog-nitive dysfunction in Alzheimer's disease(AD)model mice.Methods The 5 × FAD mice were utilized as a mod-el for Alzheimer's disease,and the sparsely labeled AAV virus overexpressing NRF1(AAV-NRF1)was adminis-tered via stereotaxic injection into the brain.The expression of NRF1 in hippocampus was determined by Western blot,the morphology of mitochondria in hippocampus was observed by transmission electron microscope,the den-dritic spines of sparsely labeled neurons in the CA1 region were visualized and quantified using confocal laser mi-croscopy,cognitive and memory functions of mice were evaluated using the Morris water maze test,while electro-physiological methods were employed to detect long-term potentiation(LTP)of synaptic efficacy.Results The ex-pression of NRF1 in the hippocampus was significantly upregulated following stereotactic injection of AAV-NRF1(P＜0.001).This intervention led to notable improvements in mitochondrial morphology within hippocampal neurons,as well as enhanced cognitive and memory functions in mice(P＜0.01).Moreover,there was a significant in-crease in dendritic spine density among neurons located in the CA1 region of the hippocampus(P＜0.001),ac-companied by long-lasting and stable long-term potentiation(LTP)and a substantial elevation in fEPSP slope(P＜0.01).Conclusion The overexpression of NRF1 in a 5 × FAD mouse model of Alzheimer's disease(AD)initia-ted the restoration of mitochondrial dysfunction and enhanced synaptic plasticity,indicating that these alterations may contribute to the therapeutic efficacy of NRF1 overexpression in ameliorating cognitive dysfunction associated with AD.