MicroRNA-29 regulates high-glucose-induced apoptosis in human retinal pigment epithelial cells through PTEN.

Hyperglycemia or high-glucose (HG)-induced apoptosis in human retinal pigment epithelial (RPE) cells is a characteristic process in diabetic retinopathy. In our study, we examined whether microRNA-29 (miR-29) may regulate HG-induced RPE cell apoptosis. Human RPE cell line, ARPE-19 cells, was treated with various high concentration of glucose in vitro. HG-induced RPE cell apoptosis was examined by terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay and miR-29 gene expression by quantitative RT-PCR (qRT-PCR). miR-29 was then downregulated in RPE cells, and its effect on HG-induced apoptosis was examined by TUNEL assay and western blot assay on caspase-7 protein. Association of miR-29 on its downstream target, PTEN, in HG-induced RPE cell apoptosis was evaluated by dual-luciferase assay and qRT-PCR. PTEN was silenced in RPE cells. The effects of PTEN downregulation on miR-29-mediated HG-induced RPE cell apoptosis were also examined by TUNEL and western blot assays. HG induced significant apoptosis in RPE cells in a dose-dependent manner. miR-29 was upregulated by HG in RPE cells. miR-29 downregulation protected HG-induced apoptosis and reduced the production of caspase-7 protein in RPE cells. PTEN was shown to be directly downregulated by HG and then upregulated by miR-29 downregulation in RPE cells. Small interfering RNA (siRNA)-mediated PTEN downregulation reversed the protective effect of miR-29 downregulation on HG-induced RPE cell apoptosis. This study demonstrates that miR-29, through inverse association of PTEN, plays an important role in the process of HG-induced apoptosis in RPE cells.

Increased activation of toll-like receptors-7 and -8 of peripheral blood mononuclear cells and upregulated serum cytokines in patients with pediatric systemic lupus erythematosus.

Autoimmune disease systemic lupus erythematosus (SLE) is associated with increased expression of pro-inflammatory cytokines such as interferons (IFNs) and specific interleukins (ILs), which are induced by toll-like receptors (TLRs). The present study aimed to examine the serum levels of cytokines, the activation of TLR-7 and TLR-8 of peripheral blood mononuclear cells (PBMCs) from pediatric SLE patients, and to investigate the response of those PBMCs to viral RNA via the TLR-7 and TLR-8 signaling. Results demonstrated that pediatric SLE patients had increased serum concentrations of interleukin (IL)-1ß, IL-6, IL-8, IL-10, and IFN-α, and promoted activation of TLR-7 and TLR-8, compared to control subjects. Moreover, the peripheral blood mononuclear cells (PBMCs) from pediatric SLE patients were more sensitive to the stimulation by the transfection with viral RNA from influenza virus, with a promoted activation of TLR-7 and TLR-8 signaling. In conclusion, pro-inflammatory cytokines, such as IL-1ß, IL-6, IL-8, IL-10, and IFN-α were promoted in pediatric SLE patients, with an increased activation of TLR-7 and TLR-8 to the stimuli, such as virus infection. It implies the TLR-7 and TLR-8 activation by virus infection might play an important role in the pathogenesis of pediatric SLE.