RESUMO
Radial glia (RG), as neurogenic progenitors and neuronal migration scaffolds, play critical roles during cortical neurogenesis. RG transformation into astrocytes, marking the transition from developmental to physiological function of these cells, is an important step during cortical development. In this study, we aim to determine the roles of microRNAs (miRNAs) during this biological process. In a conditional Dicer1-null mouse where Dicer1 is deleted in both RG and their neuronal progeny, we observe delayed RG transformation as revealed by the persistence of their radial processes, and reduced number and complexity of translocated RG cell bodies in the postnatal cerebral cortex. Downregulation of Notch1 signaling is crucial to RG transformation, and consistently we find that Notch1 signaling is enhanced in the Dicer1-null cerebral cortex. In addition, we show that, among the Notch1 ligands, Jagged2 (Jag2) is preferentially upregulated in the postnatal Dicer1-null cerebral cortex as well as primary embryonic cortical cultures with instant Dicer1 deletion. Functionally, Dicer1-deleted postnatal cerebellar cells with elevated Jag2 expression stimulate a stronger Notch1 signaling in a RG clone L2.3 when co-cultured than control cells. Therefore, we unravel a novel non-cell-autonomous mechanism that regulates RG transformation by modulating Notch1 signaling via miRNA-mediated suppression of the Nocth1 ligand Jag2. Furthermore, we validate Jag2 as a miR-124 target gene and demonstrate in vitro that Jag2 expression is highly sensitive to Dicer1 deletion. Finally, we propose a new concept of MiRNA-Sensitive target genes, identification of which may unravel a unique mode of miRNA-mediated gene expression regulation.
Assuntos
Diferenciação Celular/genética , Córtex Cerebral/citologia , RNA Helicases DEAD-box/deficiência , Células Ependimogliais/fisiologia , MicroRNAs/metabolismo , Ribonuclease III/deficiência , Células-Tronco/fisiologia , Animais , Animais Recém-Nascidos , Bromodesoxiuridina , Técnicas de Cocultura , RNA Helicases DEAD-box/genética , Embrião de Mamíferos , Proteína 7 de Ligação a Ácidos Graxos , Proteínas de Ligação a Ácido Graxo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/metabolismo , Neurônios/fisiologia , Receptores Notch/metabolismo , Ribonuclease III/genética , Transdução de Sinais/genética , TransfecçãoRESUMO
The purpose of this study was to identify specific microRNAs (miRNAs) during differentiation and maturation of interneurons and to predict their possible functions by analyzing the expression of miRNAs during in vitro differentiation of the rat interneuron precursor cell line GE6. In the experiment, the interneuron precursor cell line GE6 was cultured under three different conditions, i. e. the first was that had not added growth factors and the normal differentiation cultured for 4 days (Ge6_4d); the second was that cultured with bone morphogenetic protein-2 (BMP2) for 4 days (Ge6_bmp2); and the third was that cultured with sonic hedgehog (SHH) for 4 days (Ge6_ shh). In addition, another group of undifferentiated GE6 (Ge6_u) was applied as a control. We found in this study that the expression levels of a large number of miRNAs changed significantly during GE6 differentiation. The expression levels of miR-710, miR-290-5p and miR-3473 increased in the GE6 cells with secreted factor BMP2. These miRNAs may play important regulatory roles during interneuron differentiation.
Assuntos
Diferenciação Celular , Interneurônios/citologia , MicroRNAs/metabolismo , Animais , Proteína Morfogenética Óssea 2/química , Linhagem Celular , Proteínas Hedgehog/química , Interneurônios/metabolismo , RatosRESUMO
The current guidelines recommend that people consume 2 or more servings of fat-rich fish per week to obtain enough omega-3 (ω-3) polyunsaturated fatty acids to prevent cardiovascular events. However, the cardiovascular benefits of ω-3 polyunsaturated fatty acids in patients with diabetes are unclear, and related large-scale trials have produced conflicting results. We aimed to perform a meta-analysis of all randomized controlled trials that attempted to assess the effects of ω-3 fatty acid supplementation on cardiovascular outcomes in patients with diabetes. In PubMed, EMBASE, and the Cochrane Library, we searched for data from all randomized controlled trials on ω-3 fatty acids and cardiovascular outcomes in patients with diabetes published before July 2022. Eight eligible studies involving 57,754 participants were ultimately included. Meta-analysis showed that ω-3 fatty acid supplementation reduces cardiovascular disease (CVD) risk in patients with diabetes (rate ration [RR] = 0.93; 95% confidence interval [CI]: 0.90, 0.97; P = 0.0009). Among them, eicosapentaenoic acid (EPA), but not EPA plus docosahexaenoic acid (DHA), significantly reduced the risk of CVD in patients with diabetes (EPA [RR = 0.81; 95% CI: 0.73, 0.90; P=0.0001]). This meta-analysis suggests that ω-3 fatty acid supplementation is an effective strategy to prevent CVD in patients with diabetes, but further well-designed, large-scale randomized controlled trials are necessary to evaluate the safety of ω-3 fatty acid supplementation, and its effect on atrial fibrillation. This study was registered with PROSPERO as CRD42022346302.