Packer Davin, Martin Paul T
Neuroscience Graduate Program, The Ohio State University, Columbus, OH, USA.
Center for Gene Therapy, Abigail Wexner Research Institute, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
Mol Ther Methods Clin Dev. 2021 Feb 9;21:274-287. doi: 10.1016/j.omtm.2021.02.004. eCollection 2021 Jun 11.
Gene replacement for laminin-α2-deficient congenital muscular dystrophy 1A (MDC1A) is currently not possible using a single adeno-associated virus (AAV) vector due to the large size of the gene. encodes laminin-α2, a subunit of the trimeric laminin-211 extracellular matrix (ECM) protein that is the predominant laminin expressed in skeletal muscle. expression stabilizes skeletal muscle, in part by binding membrane receptors via its five globular (G) domains. We created a small, AAV-deliverable, micro-laminin gene therapy that expresses these G1-5 domains, , to test their therapeutic efficacy in the dy mouse model for MDC1A. We also fused the heparin-binding (HB) domain from HB epidermal growth factor-like growth factor (HB-EGF) to to test whether this would increase muscle ECM expression. dy mice treated intravenously with rAAV9.CMV. showed increased muscle ECM expression of transgenic protein relative to mice treated with rAAV9.CMV. and showed improved weight-normalized forelimb grip strength relative to untreated dy mice. Additionally, dy muscle fibers expressing either micro-laminin protein showed some measures of reduced pathology, although levels of muscle cell apoptosis and inflammation were not decreased. Although systemic expression of rAAV9.CMV. did not inhibit all disease phenotypes, these studies demonstrate the feasibility of using a micro-laminin gene therapy strategy to deliver gene replacement for MDC1A.
由于层粘连蛋白α2基因（LAMA2）的大小，目前使用单个腺相关病毒（AAV）载体对层粘连蛋白α2缺乏的先天性肌营养不良1A型（MDC1A）进行基因替代是不可能的。LAMA2编码层粘连蛋白α2，它是三聚体层粘连蛋白-211细胞外基质（ECM）蛋白的一个亚基，是骨骼肌中表达的主要层粘连蛋白。层粘连蛋白α2的表达使骨骼肌稳定，部分原因是通过其五个球状（G）结构域与膜受体结合。我们创建了一种小型的、可通过AAV递送的微层粘连蛋白基因疗法，该疗法表达这些G1-5结构域，即μLam，以在MDC1A的dy小鼠模型中测试其治疗效果。我们还将来自肝素结合（HB）表皮生长因子样生长因子（HB-EGF）的肝素结合（HB）结构域与μLam融合，以测试这是否会增加肌肉ECM的表达。用rAAV9.CMV.μLam静脉注射治疗的dy小鼠相对于用rAAV9.CMV.治疗的小鼠，转基因蛋白的肌肉ECM表达增加，并且相对于未治疗的dy小鼠，体重标准化的前肢握力有所改善。此外，表达任一微层粘连蛋白的dy肌纤维都显示出一些病理减轻的指标，尽管肌肉细胞凋亡和炎症水平没有降低。虽然rAAV9.CMV.μLam的全身表达并未抑制所有疾病表型，但这些研究证明了使用微层粘连蛋白基因治疗策略为MDC1A进行基因替代的可行性。
