Gimenez Geoffrey-Alexander, Romijn Maurits, van den Herik Joëlle, Meijer Wouter, Eggers Ruben, Hobo Barbara, De Zeeuw Chris I, Canto Cathrin B, Verhaagen Joost, Carulli Daniela
Department of Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
Department of Cerebellar Coordination & Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
Int J Mol Sci. 2025 Jan 19;26(2):819. doi: 10.3390/ijms26020819.
Semaphorin 3A (Sema3A) is an axon guidance molecule, which is also abundant in the adult central nervous system (CNS), particularly in perineuronal nets (PNNs). PNNs are extracellular matrix structures that restrict plasticity. The cellular sources of Sema3A in PNNs are unknown. Most Sema3A-bearing neurons do not express mRNA, suggesting that Sema3A may be released from other neurons. Another potential source of Sema3A is the choroid plexus. To identify sources of PNN-associated Sema3A, we focused on the cerebellar nuclei, which contain Sema3A PNNs. Cerebellar nuclei neurons receive prominent input from Purkinje cells (PCs), which express high levels of mRNA. By using a non-invasive viral vector approach, we overexpressed Cre in PCs, the choroid plexus, or throughout the CNS of mice. Knocking out in PCs or the choroid plexus was not sufficient to decrease the amount of PNN-associated Sema3A. Alternatively, knocking out throughout the CNS induced a decrease in PNN-associated Sema3A. However, motor deficits, microgliosis, and neurodegeneration were observed, which were due to Cre toxicity. Our study represents the first attempt to unravel cellular sources of PNN-associated Sema3A and shows that non-invasive viral-mediated Cre expression throughout the CNS could lead to toxicity, complicating the interpretation of Cre-mediated knock-out.
信号素3A（Sema3A）是一种轴突导向分子，在成体中枢神经系统（CNS）中也很丰富，尤其是在神经元周围网络（PNNs）中。PNNs是限制可塑性的细胞外基质结构。PNNs中Sema3A的细胞来源尚不清楚。大多数携带Sema3A的神经元不表达mRNA，这表明Sema3A可能从其他神经元释放。Sema3A的另一个潜在来源是脉络丛。为了确定与PNN相关的Sema3A的来源，我们聚焦于含有Sema3A PNNs的小脑核。小脑核神经元接收来自浦肯野细胞（PCs）的显著输入，PCs表达高水平的mRNA。通过使用非侵入性病毒载体方法，我们在PCs、脉络丛或小鼠整个CNS中过表达Cre。在PCs或脉络丛中敲除不足以减少与PNN相关的Sema3A的量。或者，在整个CNS中敲除会导致与PNN相关的Sema3A减少。然而，观察到运动缺陷、小胶质细胞增生和神经退行性变，这是由于Cre毒性所致。我们的研究是首次尝试揭示与PNN相关的Sema3A的细胞来源，并表明在整个CNS中非侵入性病毒介导的Cre表达可能导致毒性，使Cre介导的敲除的解释变得复杂。
