Molecular Biology, Cell Biology, & Biochemistry Graduate Program, Brown University, Providence, RI, USA.
Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA.
Sci Rep. 2022 Mar 17;12(1):4630. doi: 10.1038/s41598-022-08455-y.
miRNAs are necessary for neuromuscular junction (NMJ) health; however, little is known about the proteins required for their activity in this regard. We examined expression of Argonaute 2 (Ago2) and miRNA biogenesis genes in skeletal muscles during development, following nerve injury and in the SOD1 ALS mouse model. We found that these genes are enriched in neonate muscles and in adult muscles following nerve injury. Despite widespread NMJ deterioration, these genes were not increased in muscles of SOD1 mice. We also found that Ago2 distribution is linked to maturation, innervation, and health of NMJs. Ago2 increasingly concentrates in synaptic regions during NMJ maturation, disperses following experimental denervation and reconcentrates at the NMJ upon reinnervation. Similar to experimentally denervated muscles, a homogenous distribution of Ago2 was observed in SOD1 muscle fibers. To determine if Ago2 is necessary for the health of adult muscles, we excised Ago2 from Ago2 mice using adeno-associated virus mediated Cre recombinase expression. We observed modest changes in muscle histology after 3 months of Ago2 knockdown. Together, these data provide critical insights into the role of Ago2 and miRNA biogenesis genes in healthy and ALS-afflicted skeletal muscles and NMJs.
miRNAs 对于神经肌肉接头（NMJ）的健康是必要的；然而，对于在这方面发挥作用所需的蛋白质知之甚少。我们在发育过程中、神经损伤后以及 SOD1 ALS 小鼠模型中检查了 Argonaute 2（Ago2）和 miRNA 生物发生基因在骨骼肌中的表达。我们发现这些基因在新生儿肌肉和成年肌肉在神经损伤后丰富。尽管 NMJ 广泛恶化，但这些基因在 SOD1 小鼠的肌肉中没有增加。我们还发现 Ago2 的分布与 NMJ 的成熟、神经支配和健康有关。Ago2 在 NMJ 成熟过程中逐渐集中在突触区域，在实验性去神经支配后分散，并在重新神经支配时重新集中在 NMJ 上。与实验性去神经支配的肌肉类似，在 SOD1 肌纤维中观察到 Ago2 的均匀分布。为了确定 Ago2 是否对于成年肌肉的健康是必要的，我们使用腺相关病毒介导的 Cre 重组酶表达从 Ago2 小鼠中切除了 Ago2。在 Ago2 敲低 3 个月后，我们观察到肌肉组织学的轻微变化。总之，这些数据为 Ago2 和 miRNA 生物发生基因在健康和 ALS 受累骨骼肌和 NMJ 中的作用提供了重要的见解。
