Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Department of Pharmacology, Physiology, & Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07101.
Proc Natl Acad Sci U S A. 2022 Mar 29;119(13):e2107391119. doi: 10.1073/pnas.2107391119. Epub 2022 Mar 21.
Connexin 43 (Cx43) gap junctions and hemichannels mediate astrocyte intercellular communication in the central nervous system under normal conditions and contribute to astrocyte-mediated neurotoxicity in amyotrophic lateral sclerosis (ALS). Here, we show that astrocyte-specific knockout of Cx43 in a mouse model of ALS slows disease progression both spatially and temporally, provides motor neuron (MN) protection, and improves survival. In addition, Cx43 expression is up-regulated in human postmortem tissue and cerebrospinal fluid from ALS patients. Using human induced pluripotent stem cell–derived astrocytes (hiPSC-A) from both familial and sporadic ALS, we establish that Cx43 is up-regulated and that Cx43-hemichannels are enriched at the astrocyte membrane. We also demonstrate that the pharmacological blockade of Cx43-hemichannels in ALS astrocytes using GAP 19, a mimetic peptide blocker, and tonabersat, a clinically tested small molecule, provides neuroprotection of hiPSC-MN and reduces ALS astrocyte-mediated neuronal hyperexcitability. Extending the in vitro application of tonabersat with chronic administration to SOD1G93A mice results in MN protection with a reduction in reactive astrocytosis and microgliosis. Taking these data together, our studies identify Cx43 hemichannels as conduits of astrocyte-mediated disease progression and a pharmacological target for disease-modifying ALS therapies.
间隙连接蛋白 43（Cx43）连接子和半通道在正常条件下介导中枢神经系统星形胶质细胞细胞间通讯，并有助于肌萎缩侧索硬化症（ALS）中的星形胶质细胞介导的神经毒性。在这里，我们表明，ALS 小鼠模型中星形胶质细胞特异性敲除 Cx43 可在空间和时间上减缓疾病进展，提供运动神经元（MN）保护并提高生存率。此外，Cx43 在人类 ALS 患者的尸检组织和脑脊液中表达上调。使用来自家族性和散发性 ALS 的人诱导多能干细胞衍生的星形胶质细胞（hiPSC-A），我们确定 Cx43 上调，并且 Cx43-半通道在星形胶质细胞膜上富集。我们还证明，使用 GAP 19（一种模拟肽阻滞剂）和 tonabersat（一种经过临床测试的小分子）在 ALS 星形胶质细胞中阻断 Cx43-半通道可提供 hiPSC-MN 的神经保护作用，并降低 ALS 星形胶质细胞介导的神经元过度兴奋。将 tonabersat 的慢性给药的体外应用扩展到 SOD1G93A 小鼠中，导致 MN 保护，减少反应性星形胶质细胞增生和小胶质细胞增生。将这些数据综合起来，我们的研究确定 Cx43 半通道是星形胶质细胞介导的疾病进展的通道，也是用于改变疾病的 ALS 治疗的药理学靶标。
