Tu Tian, Cai Xiao-Lu, Sun Zhong-Ping, Yang Chen, Jiang Juan, Wan Lily, Ai Jia-Qi, Wang Yan, Coulibaly Sidiki, Tang Bei-Sha, Wang Jian, Wang Jian-Hong, Zhang Yan, Wang Xiao-Ping, Peng Ying, Wang Hua, Pan Aihua, Yan Xiao-Xin, Tu Ewen, Zhang Qi-Lei
Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, 410013, Hunan, China.
Sci Rep. 2025 May 6;15(1):15834. doi: 10.1038/s41598-025-00094-3.
α-Smooth muscle actin (αSMA) is best characterized as the building block of thin filaments in smooth muscle cells. We observed a clear αSMA immunolabeling in adult human hippocampal mossy fibers (MF), prompting us to explore this novel pattern in phylogenic and ontogenic perspectives in the present study. αSMA immunolabeling occurred distinctively at the hippocampal MF terminals in humans from infancy to elderly. Hippocampal MF αSMA immunolabeling was not observed in mice and rats, visible in CA3 in guinea pigs and cats, and prominent in CA3 and dentate hilus in Rhesus monkeys. MF αSMA immunolabeling in human hippocampus emerged and refined from the last gestational trimester to early infancy. A transient overall neuronal labeling of ɑSMA was observed in prenatal human brains. ɑSMA expression was detected in human and rat primary neuronal cultures. The specificity of ɑSMA antibodies was confirmed by ACTA2 small interfering RNA (siRNA) silencing in SH-SY5Y cells. With this validation, we detected a higher αSMA protein level in dentate gyrus lysates relative to other human brain areas. Taken together, αSMA is distinctly expressed in human hippocampal mossy fibers. This pattern is related to hippocampal evolution among mammals and involves a refinement of neuronal αSMA expression during brain development.
α平滑肌肌动蛋白（αSMA）的最佳特征是作为平滑肌细胞中细肌丝的组成部分。我们观察到在成人人类海马苔藓纤维（MF）中有明显的αSMA免疫标记，这促使我们在本研究中从系统发育和个体发育的角度探索这种新模式。从婴儿期到老年期，αSMA免疫标记在人类海马MF终末明显出现。在小鼠和大鼠中未观察到海马MF的αSMA免疫标记，在豚鼠和猫的CA3区可见，在恒河猴的CA3区和齿状回门明显。人类海马中的MF αSMA免疫标记从妊娠晚期到婴儿早期出现并逐渐完善。在产前人类大脑中观察到ɑSMA的短暂整体神经元标记。在人类和大鼠原代神经元培养物中检测到ɑSMA表达。通过在SH-SY5Y细胞中用ACTA2小干扰RNA（siRNA）沉默来确认ɑSMA抗体的特异性。通过这种验证，我们检测到齿状回裂解物中的αSMA蛋白水平相对于其他人类脑区更高。综上所述，αSMA在人类海马苔藓纤维中明显表达。这种模式与哺乳动物海马的进化有关，并且涉及大脑发育过程中神经元αSMA表达的完善。
