miR-92a promotes proliferation and inhibits apoptosis of prostate cancer cells through the PTEN/Akt signaling pathway.

MicroRNAs (miRNAs) play an important role in the development of prostate cancer (PCa). Recent studies have shown that miR-92a expression is significantly increased in various cancers including PCa. However, its specific mechanism in PCa remains unknown. The goal of this study was to investigate the effect of miR-92a expression on the function and mechanism of PCa. PCa cell lines PC-3 and LNCap were transfected with miR-92a inhibitor to reduce the expression of miR-92a, respectively. The cell proliferation, cell viability, apoptosis, cell invasion and migration ability of PCa cells were examined by CCK8 assay, cell cloning, flow cytometry, Transwell assay and scratch assay, respectively. The effects of miR-92a on PTEN/Akt signaling pathway-related factors (PI3k, Akt, p-PI3k, p-Akt, PTEN) were also observed by RT-qPCR and Western blot. Compared with the control group and NC inhibitor group, the viability, cell migration and invasion ability of PC-3 and LNCap cells were decreased and apoptosis was significantly increased after interference with miR-92a expression. In addition, the mRNA and protein levels of PTEN in PC-3 and LNCap cells in the miR-92a inhibitor group were significantly increased, while the phosphorylation levels of PI3K and AKT were significantly decreased. MiR-92a might play a key role in regulating the proliferation, migration and invasion of PCa cells through the PTEN/Akt signaling pathway. Inhibition of miR-92a expression has practical value against PCa and provides ideas for further clinical treatment of patients with PCa.

Leukodystrophy associated with mitochondrial complex I deficiency due to a novel mutation in the NDUFAF1 gene.

Mitochondrial energy metabolism disorder is one of the important reasons of leukodystrophy. Mutations of mitochondrial complex I genes have been implicated in more common neurological disorders such as Leigh syndrome. We describe a case of a child manifested as regression of mental and motor development, aggravated obviously after suffering infection. Physical and auxiliary examinations demonstrated that a series of changes including white matter lesions of magnetic resonance imaging, peripheral neuropathy with high muscle tension and hyperreflexia of limbs pointed to the diagnosis of leukodystrophy, with what can't explain the high levels of lactate and creatine kinase. Spontaneously, genetic analysis covered known leukodystrophy and mitochondrial genes were adapted for this child and his parents. Results showed the child was compound heterozygous mutation (c.278A > G; c.247G > A) within exon 2 in the NDUFAF1 gene, his parents carried a heterozygous mutation each. The authors report a case of leukodystrophy associated with mitochondrial complex I deficiency due to a novel mutation in the NDUFAF1 gene. This is the first report that NDUFAF1 mutations cause leukodystrophy.

Role of p115RhoGEF in lipopolysaccharide-induced mouse brain microvascular endothelial barrier dysfunction.

BACKGROUND: In endothelial cells, exposure to lipopolysaccharide (LPS) results in barrier dysfunction through a complex signaling mechanism. The RhoA/Rho-kinase pathway plays a significant role in endothelial cell permeability. p115RhoGEF, a specific guanine nucleotide exchange factors (GEFs) activates RhoA, triggering RhoA-dependent cytoskeletal remodeling. However, little is known about the role of p115RhoGEF in LPS-induced brain endothelial barrier breakdown. We hypothesized that suppression of p115RhoGEF may inhibit activation of RhoA and prevent LPS-induced brain microvascular endothelial cell hyperpermeability. METHODS: The cultured monolayer of bEnd.3 cells, an immortalized mouse brain endothelial cell line, was used in this study. bEnd.3 cells were pretreated with specific siRNA to knockdown p115RhoGEF or C3 transferase to inhibit RhoA activity, and then incubated with LPS (5µg/ml). The degree of RhoA activation was determined by a Rhotekin-based pull-down assay, and expression of p115RhoGEF, zonula occludens-1 (ZO-1), occludin and claudin-5 proteins were detected by Western blot analysis. The barrier function was measured by transendothelial electrical resistance (TEER). F-actin cytoskeleton was visualized by Rhodamine-phalloidin staining. RESULTS: The expression level of p115RhoGEF protein was significantly increased in LPS-treated bEnd.3 cells. The activity of RhoA was enhanced after LPS stimulation and pretreatment with p115RhoGEF siRNA or exoenzyme C3 transferase reduced RhoA activation significantly as shown by the pull-down assay. Furthermore, depletion of p115RhoGEF partially prevented the LPS-induced decrease in TEER, stress fiber formation and tight junction proteins degradation. CONCLUSIONS: These results suggest that p115RhoGEF is important for LPS signaling to RhoA and LPS-induced endothelial barrier dysfunction, providing new insight into the function of RhoGEFs in inflammation.