Spag6 Mutant Mice Have Defects in Development and Function of Spiral Ganglion Neurons, Apoptosis, and Higher Sensitivity to Paclitaxel
作者
Li, XF;Xu, L;Sun, GY;Wu, XM;Bai, XH;Li, JF;Strauss, JF;Zhang, ZB;Wang, HB
作者单位
[Li, Xiaofei; Xu, Lei; Wu, Xianmin; Wang, Haibo] Shandong Univ, Prov Hosp, Otolaryngol Head & Neck Surg, Jinan, Shandong, Peoples R China.;-;[Li, Xiaofei; Sun, Gaoying; Bai, Xiaohui; Li, Jianfeng; Wang, Haibo] Shandong Prov Key Lab Otol, Jinan, Shandong, Peoples R China.;-;[Strauss, Jerome F.; Zhang, Zhibing] Virginia Commonwealth Univ, Dept Obstet & Gynecol, Richmond, VA 23298 USA.;-;[Strauss, Jerome F.; Zhang, Zhibing] Virginia Commonwealth Univ, Dept Biochem & Mol Biol, Richmond, VA 23298 USA.;-;[Wu, Xianmin] Wenzhou Med Univ, Affiliated Hosp 1, Dept Otolaryngol Head & Neck Surg, Wenzhou, Peoples R China.
摘要
Mammalian Sperm Associated Antigen 6 (SPAG6) is the orthologue of Chlamydomonas PF16, a protein localized in the axoneme central apparatus. Recent studies showed that Spag6 has a role in brain neuronal proliferation and differentiation. The mammalian spiral ganglion neurons (SGNs) are specialzed bipolar neurons in the inner ear. However, the role of SPAG6 in SGN has not been elucidated. Therefore, We hypothesized that a Spag6 knockout would affect the development and function of SGNs. We utilized Spag6-deficient mice and SGN explants to define the role of SPAG6. On postnatal day 30 (P30) mutant mice had lower SGN density compared to their wild-type littermates, and more apoptosis was evident in the mutants. Increased Bax expression, a disturbed distribution of cytochrome c, and cleaved caspase-3 positive staining indicated that increased apoptosis involved a mitochondrial pathway. Transmission electron microscopy revealed abnormalities in the ultrastructure of mutant SGNs as early as P7. In vitro, lack of SPAG6 affected the growth of neurites and growth cones. Additionally, SPAG6 deficiency decreased synapse density in SGN explants. Finally, Spag6 mutant SGNs were more sensitive to the microtubule stabilizing agent, paclitaxel. These findings suggest that Spag6 plays a crucial role in SGN development and function.
关键词
MICROTUBULE-ASSOCIATED PROTEIN; MINIMAL RESIDUAL DISEASE; GROWTH; CANCER; EXPRESSION; GENES; CELLS; IDENTIFICATION; REGENERATION; MIGRATION
基本信息
