Department of Biotechnology and Bioinformatics, School of life Sciences, University of Hyderabad, Hyderabad, Telangana.
Department of Pharmaceutics, JSS College of Pharmacy, Udhagamandalam, Tamil Nadu, India.
Ann Neurol. 2017 Sep;82(3):429-443. doi: 10.1002/ana.25028.
Loss of cognition even after survival is the salient feature of cerebral malaria (CM). Currently, the fate of neuronal morphology is not studied at the ultrastructural level in CM. Recent studies suggest that maintenance of neuronal morphology and dendritic spine density (actin dynamics in particular) are essential for proper cognitive function. LIMK-1/cofilin-1 signaling pathway is known to be involved in the maintenance of actin dynamics through regulation of cofilin-1, and in executing learning and memory functions.
Using an experimental mouse model, we analyzed the behavioral parameters of asymptomatic mice with CM by performing a rapid murine coma and behavior scale experiment. We performed Golgi-Cox staining to assess neuronal morphology, dendritic spine density, and arborization in brain cortex subjected to Plasmodium berghei ANKA infection compared to asymptomatic, anemic, and control groups. We studied the neural gene expression pattern of LIMK-1, cofilin-1, and β-actin in all the experimental groups by semiquantitative and quantitative polymerase chain reaction followed by immunoblotting and immunofluorescence.
We observed significant loss of dendritic spine density, abnormal spine morphology, reduced dendritic arborization, and extensive dendritic varicosities in the cortical neurons of CM-infected brain. Furthermore, these observations correlated with diminished protein levels of LIMK-1, cofilin-1, phospho-cofilin-1, and β-actin in the whole brain lysates as well as formation of actin-cofilin rods in the brain sections of symptomatic mice with CM.
Overall, our findings suggest that the altered neuronal morphology and dysregulation of LIMK-1/cofilin-1 pathway could affect the cognitive outcome after experimental CM. Therefore, this study could help to establish newer therapeutic strategies addressing long-term cognitive impairment after CM. Ann Neurol 2017;82:429-443.
即使在存活后认知丧失也是脑疟疾（CM）的显著特征。目前，CM 中神经元形态的命运尚未在超微结构水平上进行研究。最近的研究表明，维持神经元形态和树突棘密度（特别是肌动蛋白动力学）对于适当的认知功能是必不可少的。LIMK-1/ 丝切蛋白-1 信号通路通过调节丝切蛋白-1 参与肌动蛋白动力学的维持，并执行学习和记忆功能。
使用实验性小鼠模型，我们通过快速鼠昏迷和行为量表实验分析了无症状 CM 小鼠的行为参数。我们进行 Golgi-Cox 染色，以评估与无症状、贫血和对照组相比，受疟原虫伯氏疟原虫 ANKA 感染的大脑皮质中的神经元形态、树突棘密度和分支。我们通过半定量和定量聚合酶链反应以及免疫印迹和免疫荧光研究了所有实验组中 LIMK-1、丝切蛋白-1 和 β-肌动蛋白的神经基因表达模式。
我们观察到 CM 感染大脑皮质神经元中的树突棘密度显著丧失、异常的棘形态、树突分支减少和广泛的树突膨出。此外，这些观察结果与整个脑裂解物中 LIMK-1、丝切蛋白-1、磷酸化丝切蛋白-1 和 β-肌动蛋白的蛋白水平降低以及 CM 症状小鼠脑切片中肌动蛋白-丝切蛋白棒的形成相关。
总体而言，我们的研究结果表明，神经元形态的改变和 LIMK-1/丝切蛋白-1 通路的失调可能会影响实验性 CM 后的认知结果。因此，本研究可以帮助建立针对 CM 后长期认知障碍的新治疗策略。Ann Neurol 2017;82:429-443.
