Ma Xiaochen, Yu Sejie, Zhang Min, Mei Shaoyi, Ling Yunzhi, Huang Xiaosheng, Dong Songguo, Fan Baojian, Zhao Jun
The Second Clinical Medical College of Jinan University, Department of Ophthalmology, Shenzhen People's Hospital, Shenzhen, 518020, Guangdong, China.
Department of Ophthalmology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China.
Biochem Biophys Res Commun. 2025 Feb 2;747:151123. doi: 10.1016/j.bbrc.2024.151123. Epub 2024 Dec 4.
Phosphoinositide kinase, FYVE-type zinc finger containing (PIKFYVE) was recently identified as a causative gene for cataract. Pikfyve phosphatidylinositol phosphate kinase domain-deficient (pikfyve) zebrafish lens and PIKFYVE-inhibited human lens epithelial cells developed vacuoles, colocalized with late endosome marker RAB7. In this study, the pikfyvezebrafish with vacuole-like cataract underwent transcriptomic and proteomic analyses to explore the underlying mechanisms of vacuole formation. PIKFYVE-knockout and PIKFYVE-inhibited human lens epithelial cells with vacuoles further verified these omics results and rescued with Bafilomycin A1(Baf-A1) and U18666A. We discovered no significant differences in lysosomal fusion, but upregulation in acid hydrolase. The composition of late endosomal membrane was changed, and vacuolar ATPase and endosomal sorting complexes required for transport (ESCRT) at late endosome were upregulated. These changes are related with the late endosome homeostasis. Strikingly, vacuoles in human lens epithelial cells could be partially rescued by Baf-A1 and almost completely rescued by U18666A. Collectively, these findings suggest that vacuoles in pikfyve zebrafish lens and PIKFYVE-inhibited cells were colocalized with swollen late endosomes, and generated by perturbing late endosome homeostasis due to enhanced ESCRT mechanisms and decreased stability in late endosomal membrane. This study expands our understanding of the mechanisms underlying cataract development and reveals potentially effective therapeutic targets.
含FYVE型锌指的磷酸肌醇激酶（PIKFYVE）最近被鉴定为白内障的致病基因。Pikfyve磷脂酰肌醇磷酸激酶结构域缺陷型（pikfyve）斑马鱼晶状体以及PIKFYVE抑制的人晶状体上皮细胞出现空泡，与晚期内体标志物RAB7共定位。在本研究中，对患有空泡样白内障的pikfyve斑马鱼进行了转录组学和蛋白质组学分析，以探索空泡形成的潜在机制。具有空泡的PIKFYVE基因敲除和PIKFYVE抑制的人晶状体上皮细胞进一步验证了这些组学结果，并用巴弗洛霉素A1（Baf-A1）和U18666A进行了挽救。我们发现溶酶体融合无显著差异，但酸性水解酶上调。晚期内体膜的组成发生了变化，晚期内体处的液泡ATP酶和运输所需的内体分选复合物（ESCRT）上调。这些变化与晚期内体稳态有关。引人注目的是，人晶状体上皮细胞中的空泡可被Baf-A1部分挽救，几乎可被U18666A完全挽救。总的来说，这些发现表明，pikfyve斑马鱼晶状体和PIKFYVE抑制细胞中的空泡与肿胀的晚期内体共定位，是由于ESCRT机制增强和晚期内体膜稳定性降低扰乱晚期内体稳态而产生的。本研究扩展了我们对白内障发生机制的理解，并揭示了潜在有效的治疗靶点。
