Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, Jiangsu, China.
Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, 210009, Jiangsu, China.
Reprod Biol Endocrinol. 2024 Apr 3;22(1):36. doi: 10.1186/s12958-024-01204-y.
Microtubule-associated protein 1a (Map1a) is a microtubule (MT) regulatory protein that binds to the MT protofilaments in mammalian cells to promote MT stabilization. Maps work with MT cleavage proteins and other MT catastrophe-inducing proteins to confer MT dynamics to support changes in the Sertoli cell shape to sustain spermatogenesis. However, no functional studies are found in the literature to probe its role in spermatogenesis. Using an RNAi approach, coupled with the use of toxicant-induced testis (in vivo)- and Sertoli cell (in vitro)-injury models, RNA-Seq analysis, transcriptome profiling, and relevant bioinformatics analysis, immunofluorescence analysis, and pertinent biochemical assays for cytoskeletal organization, we have delineated the functional role of Map1a in Sertoli cells and testes. Map1a was shown to support MT structural organization, and its knockdown (KD) also perturbed the structural organization of actin, vimentin, and septin cytoskeletons as these cytoskeletons are intimately related, working in concert to support spermatogenesis. More importantly, cadmium-induced Sertoli cell injury that perturbed the MT structural organization across the cell cytoplasm was associated with disruptive changes in the distribution of Map1a and a surge in p-p38-MAPK (phosphorylated p38-mitogen-activated protein kinase) expression but not total p38-MAPK. These findings thus support the notion that p-p38-MAPK activation is involved in cadmium-induced Sertoli cell injury. This conclusion was supported by studies using doramapimod, a specific p38-MAPK phosphorylation (activation) inhibitor, which was capable of restoring the cadmium-induced disruptive structural organization of MTs across the Sertoli cell cytoplasm. In summary: this study provides mechanistic insights regarding restoration of toxicant-induced Sertoli cell and testis injury and male infertility.
微管相关蛋白 1a（Map1a）是一种微管（MT）调节蛋白，它与哺乳动物细胞中的 MT 原纤维结合，促进 MT 的稳定。Maps 与 MT 切割蛋白和其他诱导 MT 崩溃的蛋白一起作用，赋予 MT 动力学特性，以支持支持生精的 Sertoli 细胞形状变化。然而，在文献中没有发现功能研究来探讨其在生精中的作用。我们采用 RNAi 方法，结合使用有毒物质诱导的睾丸（体内）和 Sertoli 细胞（体外）损伤模型、RNA-Seq 分析、转录组分析、相关生物信息学分析、免疫荧光分析和有关细胞骨架组织的生化分析，阐明了 Map1a 在 Sertoli 细胞和睾丸中的功能作用。结果表明 Map1a 支持 MT 结构组织，其敲低（KD）也扰乱了肌动蛋白、波形蛋白和 septin 细胞骨架的结构组织，因为这些细胞骨架密切相关，协同作用支持生精。更重要的是，镉诱导的 Sertoli 细胞损伤扰乱了整个细胞质中的 MT 结构组织，与 Map1a 分布的破坏性变化以及 p-p38-MAPK（磷酸化 p38-有丝分裂原激活蛋白激酶）表达的激增有关，但与总 p38-MAPK 无关。这些发现支持了 p-p38-MAPK 激活参与镉诱导的 Sertoli 细胞损伤的观点。这一结论得到了使用 doramapimod（一种特异性 p38-MAPK 磷酸化（激活）抑制剂）的研究的支持，该抑制剂能够恢复镉诱导的 Sertoli 细胞质中 MT 的破坏性结构组织。总之：本研究为恢复有毒物质诱导的 Sertoli 细胞和睾丸损伤以及男性不育提供了机制见解。
