Introduction
MicroRNA (miRNA) is known to be involved in nerve injury. Our study aimed to identify the role and mechanism of miR-1b in rat neuron proliferation, regeneration and apoptosis.

Material and methods
Neurons were successfully separated and identified using a microscope and immunofluorescence staining of microtubule-associated protein 2 (MAP-2). The expressions of miR-1b and Krüppel-like factor 7 (KLF7) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Neuron viability and apoptosis were detected by MTT assay and flow cytometry, respectively. Neuron regeneration states were observed using a microscope and analysed by the ImageJ software. Expressions of C-caspase-3 and cell regeneration-related proteins (nerve growth factor [NGF], ciliary neurotrophic factor [CNTF] and brain-derived neurotrophic factor [BDNF]) were measured by Western blot. Target genes and potential binding sites of KLF7 and miR-1b were predicted by TargetScan 7.2 and confirmed by dual luciferase reporter assay.

Results
Neurons were identified as MAP-2-positive. Up-regulation of miR-1b reduced neuron viability and regenerative ability, promoted neuron apoptosis and C-caspase-3 expression, and down-regulated the expressions of cell regeneration-related proteins. KLF7 was the target gene of miR-1b. Overexpressed KLF7 rescued the effects of up-regulation of miR-1b on neuron viability, regeneration and apoptosis. Expressions of NGF, CNTF and BDNF were suppressed yet C-caspase-3 expression was up-regulated by miR-1b mimic, which was partially rescued by overexpressed KLF7.

Conclusions
Up-regulation of miR-1b promoted rat neuron proliferation and regeneration yet inhibited apoptosis via targeting KLF7.



中文翻译：

---

MiR-1b 上调抑制大鼠神经元增殖和再生，但通过靶向 KLF7 促进细胞凋亡

介绍
已知微RNA (miRNA) 与神经损伤有关。我们的研究旨在确定 miR-1b 在大鼠神经元增殖、再生和凋亡中的作用和机制。

材料与方法
使用显微镜和微管相关蛋白 2 (MAP-2) 的免疫荧光染色成功分离和鉴定神经元。通过定量实时聚合酶链反应 (qRT-PCR) 检测 miR-1b 和 Krüppel 样因子 7 (KLF7) 的表达。分别通过MTT法和流式细胞术检测神经元活力和细胞凋亡。使用显微镜观察神经元再生状态并通过 ImageJ 软件进行分析。通过蛋白质印迹测量 C-caspase-3 和细胞再生相关蛋白（神经生长因子 [NGF]、睫状神经营养因子 [CNTF] 和脑源性神经营养因子 [BDNF]）的表达。KLF7 和 miR-1b 的靶基因和潜在结合位点由 TargetScan 7.2 预测，并通过双荧光素酶报告基因检测证实。

结果
神经元被鉴定为MAP-2阳性。上调 miR-1b 降低神经元活力和再生能力，促进神经元凋亡和 C-caspase-3 表达，下调细胞再生相关蛋白的表达。KLF7 是 miR-1b 的靶基因。过表达的 KLF7 挽救了 miR-1b 上调对神经元活力、再生和细胞凋亡的影响。NGF、CNTF 和 BDNF 的表达受到抑制，而 C-caspase-3 的表达被 miR-1b 模拟物上调，这部分被过度表达的 KLF7 挽救。

结论
miR-1b 的上调通过靶向 KLF7 促进大鼠神经元增殖和再生，同时抑制细胞凋亡。