Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan.
Laboratory of Veterinary Anatomy, The Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.
J Vet Med Sci. 2023 Mar 1;85(3):266-270. doi: 10.1292/jvms.22-0552. Epub 2023 Jan 24.
Prosaposin is a precursor of lysosomal hydrolases activator proteins, saposins, and also acts as a secretory protein that is not processed into saposins. Prosaposin elicits neurotrophic function via G protein-coupled receptor (GPR) 37, and prosaposin deficiency causes abnormal vestibuloauditory end-organ development. In this study, immunohistochemistry was used to examine prosaposin and GPR37 expression patterns in the mouse cochlear and vestibular nuclei. Prosaposin immunoreactivity was observed in neurons and glial cells in both nuclei. GPR37 immunoreactivity was observed in only some neurons, and its immunoreactivity in the vestibular nucleus was weaker than that in the cochlear nucleus. This study suggests a possibility that prosaposin deficiency affects not only the end-organs but also the first center of the vestibuloauditory system.
原胆堿脂酶是溶酶体水解酶激活蛋白（saposin）前体，也作为一种分泌蛋白发挥作用，不被加工成 saposin。原胆堿脂酶通过 G 蛋白偶联受体（GPR）37 发挥神经营养作用，原胆堿脂酶缺乏会导致前庭听觉终末器官发育异常。在这项研究中，采用免疫组织化学方法检测了小鼠耳蜗和前庭神经核中原胆堿脂酶和 GPR37 的表达模式。原胆堿脂酶免疫反应性可见于两个核中的神经元和神经胶质细胞。GPR37 免疫反应性仅见于部分神经元，且其在前庭神经核中的免疫反应性弱于耳蜗神经核。本研究提示，原胆堿脂酶缺乏不仅影响终末器官，还可能影响前庭听觉系统的第一中枢。
