RESUMO
INTRODUCTION: Diabetic nephropathy (DN) is one of the most common and lethal diabetic complications worldwide and is associated with a high risk of mortality. However, the exact mechanism behind its development is unknown. The mesangial cells (MCs) and non-coding RNAs are critical for DN, but it is unknown whether a MEG3/miR-21/ORAI1 regulatory axis exists in MCs. Hence, in this study, we aimed to understand whether the MEG3/miR-21/ORAI1 regulatory axis has a role in the pathophysiology of DN. RESULTS: We demonstrated that high-glucose stimuli downregulated MEG3 and ORAI1 expression while enhancing miR-21 expression. Exogenous miR-21 mimics inhibited ORAI1 expression, which was partially salvaged or reversed by MEG3 overexpression. Furthermore, RIP assay demonstrated that the beads labeled with AGO2 antibody could enrich more miR-21 and MEG3 than those labeled with control IgG antibody; both of them formed the RNA-induced silencing complex. Further, the biochemical indicators of db/db mice significantly improved, and renal fibrinoid necrosis was ameliorated using a miR-21 inhibitor. CONCLUSION: The MEG3/miR-21/ORAI1 axis regulates the manifestation of DN in diabetic mice and MCs, and the miR-21 inhibitor can be a potential therapeutic strategy to alleviate DN, once the presence of such an axis is found in humans.
Assuntos
Diabetes Mellitus Experimental , Nefropatias Diabéticas , MicroRNAs , RNA Longo não Codificante , Animais , Humanos , Camundongos , Diabetes Mellitus Experimental/metabolismo , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Necrose , Proteína ORAI1 , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
Rab5a is a regulatory guanosine triphosphatase that is associated with the transport and fusion of endocytic vesicles, and participates in regulation of intracellular signaling pathways embraced by cells to adapt to the specific environment. Rab5a is also correlated with lung, stomach, and hepatocellular carcinomas. Here, we detected Rab5a in paraffin-embedded samples of 20 ovarian cysts, 20 benign cystadenomas, and 39 ovarian cancers by immunohistochemistry, and observed that Rab5a expression was significantly higher in ovarian cancer (P = 0.0001). By setting up stable HO-8910 cell lines expressing Rab5a or dominant negative Rab5a (Rab5a:S34N), we found that Rab5a overexpression enhanced the cell growth by promoting G1 into S phase. In contrast, Rab5a:S34N inhibited this process. Additionally, APPL1 (adaptor protein containing PH domain, PTB domain, and Leucine zipper motif), a downstream effector of Rab5a, was also involved in promoting HO-8910 cell cycle progress. But this function was blocked by Rab5a:S34N. Laser scanning confocal microscopy represented the colocalization of APPL1 and Rab5a in the plasmolemma, which changed with the time of epidermal growth factor (EGF) stimulation. We also found APPL1 could transfer from the membranes into the nucleus where it interacted with NuRD/MeCP1 (the nucleosome remodeling and histone deacetylase multiprotein complex). NuRD is reported to be involved in the deacetylation of histone H3 and H4 to regulate nuclear transcription. So Rab5a promoted proliferation of ovarian cancer cells, which may be associated with the APPL1-related epidermal growth factor signaling pathway.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Fator de Crescimento Epidérmico/fisiologia , Neoplasias Ovarianas/patologia , Transdução de Sinais/fisiologia , Proteínas rab5 de Ligação ao GTP/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Ciclo Celular , Proliferação de Células , Ciclina D1/genética , Feminino , Regulação da Expressão Gênica , Humanos , Pessoa de Meia-Idade , Proteínas rab5 de Ligação ao GTP/genéticaRESUMO
This study was purposed to investigate the effects of siRNA targeting c-myc on apoptosis induction, proliferation in inhibition as well as c-myc protein and mRNA expression in human myeloid leukemia cell line HL-60 cells. C-myc siRNA synthesized in vitro was transfected into HL-60 cells by liposome. Changes of cell morphology were observed. Growth inhibition was detected by MTT assay and colony formation assay, and cell apoptosis was determined by DNA ladder. The expressions of c-myc mRNA and protein were detected by RT-PCR and Western-blot respectively. The results indicated that c-myc siRNA remarkably inhibited the cell proliferation, with an IC(50) value of 150 nmol/L. Data of DNA ladder showed that HL-60 cells apoptosis could be efficiently induced by c-myc siRNA, the apoptosis rate positively correlated with the time duration of treatment with drugs. The c-myc mRNA and protein expressions on HL-60 cells decreased after treatment with c-myc siRNA, which negatively correlated with time duration of treatment. It is concluded that c-myc siRNA can efficiently induce growth inhibition, decrease the expressions of c-myc mRNA and protein, and induce apoptosis in HL-60 cells.
