Mutations in the Leucine-rich repeat kinase 2 (LRRK2) gene are the most prevalent cause of familial Parkinson's disease (PD). The increase in LRRK2 kinase activity observed in the pathogenic G2019S mutation is important for PD development. Several studies have reported that increased LRRK2 kinase activity and treatment with LRRK2 kinase inhibitors decreased and increased ciliogenesis, respectively, in mouse embryonic fibroblasts (MEFs) and retinal pigment epithelium (RPE) cells. In contrast, treatment of SH-SY5Y dopaminergic neuronal cells with PD-causing chemicals increased ciliogenesis. Because these reports were somewhat contradictory, we tested the effect of LRRK2 kinase activity on ciliogenesis in neurons. In SH-SY5Y cells, LRRK2 inhibitor treatment slightly increased ciliogenesis, but serum starvation showed no increase. In rat primary neurons, LRRK2 inhibitor treatment repeatedly showed no significant change. Little difference was observed between primary cortical neurons prepared from wild-type (WT) and G2019S^+/- mice. However, a significant increase in ciliogenesis was observed in G2019S^+/- compared to WT human fibroblasts, and this pattern was maintained in neural stem cells (NSCs) differentiated from the induced pluripotent stem cells (iPSCs) prepared from the same WT/G2019S fibroblast pair. NSCs differentiated from G2019S and its gene-corrected WT counterpart iPSCs were also used to test ciliogenesis in an isogenic background. The results showed no significant difference between WT and G2019S regardless of kinase inhibitor treatment and B27-deprivation-mimicking serum starvation. These results suggest that LRRK2 kinase activity may be not a direct regulator of ciliogenesis and ciliogenesis varies depending upon the cell type or genetic background.

中文翻译：

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纤毛发生不受神经元中 LRRK2 激酶活性的直接调节。

富含亮氨酸重复激酶 2 ( LRRK2) 的突变) 基因是家族性帕金森病 (PD) 的最常见原因。在致病性 G2019S 突变中观察到的 LRRK2 激酶活性的增加对于 PD 发展很重要。几项研究报告称，在小鼠胚胎成纤维细胞 (MEF) 和视网膜色素上皮 (RPE) 细胞中，LRRK2 激酶活性的增加和 LRRK2 激酶抑制剂的治疗分别减少和增加了纤毛发生。相比之下，用引起 PD 的化学物质处理 SH-SY5Y 多巴胺能神经元细胞会增加纤毛发生。因为这些报告有些矛盾，我们测试了 LRRK2 激酶活性对神经元纤毛发生的影响。在 SH-SY5Y 细胞中，LRRK2 抑制剂处理略微增加了纤毛发生，但血清饥饿没有增加。在大鼠初级神经元中，LRRK2抑制剂反复治疗未见明显变化。从野生型 (WT) 和 G2019S 制备的原代皮层神经元之间几乎没有差异^+/-小鼠。然而，与 WT 人成纤维细胞相比，在 G2019S ^+/-中观察到纤毛发生显着增加，并且这种模式在由相同 WT/G2019S 成纤维细胞制备的诱导多能干细胞 (iPSC) 分化的神经干细胞 (NSC) 中得以维持一对。从 G2019S 分化出来的 NSCs 及其基因校正的 WT 对应物 iPSCs 也被用于测试等基因背景下的纤毛发生。结果表明，无论激酶抑制剂治疗和 B27 剥夺模拟血清饥饿如何，WT 和 G2019S 之间没有显着差异。这些结果表明 LRRK2 激酶活性可能不是纤毛发生的直接调节因子，纤毛发生因细胞类型或遗传背景而异。