Apoptosis in Laminin alpha2-Deficient Muscle Pathology

层粘连蛋白 α2 缺陷的肌肉病理学中的细胞凋亡

• 批准号: 7046786
• 负责人: Janice A Dominov
• 金额: $ 37.7万
• 依托单位: BOSTON BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7046786
• 关键词: BCL2 gene /protein; Bax gene /protein; RNA interference; apoptosis; basement membrane; congenital disorders; gene expression; gene mutation; genetic models; genetically modified animals; histology; immunocytochemistry; laboratory mouse; laminin; muscle cells; muscular dystrophy; pathologic process; protein deficiency; protein structure function; terminal nick end labeling; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Congenital muscular dystrophy is often caused by deficiency in laminin a2 (merosin) expression in the basement membrane surrounding muscle fibers. Merosin-deficient congenital muscular dystrophy (MCMD) is characterized by severe muscle weakness shortly after birth that does not improve significantly enough to allow normal ambulatory motion. The dy mutant mouse lines also lack normal laminin u2 expression and provide an experimental models for this disease. Severe mutants such as the dyw strain undergo muscle fiber degeneration followed by regeneration, but these fibers die in a process involving apoptosis. Ultimately mice die within 4 months of age. We have found that muscle specific overexpression of Bcl-2 (an inhibitor of apoptosis) can significantly prolong the survival dyw mice and improve post-weaning growth thus indicating that regulation of the cell death specifically in muscle cells has a dramatic effect on this disease progression. Additionally, we find that d/v animals deficient in Bax, a related pro-apoptotic protein, exhibit even greater longevity and growth along with reduced hind limb paralysis associated with laminin a2- deficient myelination defects. Experiments are proposed to further explore the role of Bcl-2 and Bax in the progression of laminin a2-deficient muscle pathology and determine their effects on apoptosis, regeneration and survival at both early and later stages of disease. We will also examine expression of other apoptotic regulatory molecules, specifically FLIPL, ARC, XIAP, and Apaf-1, in normal and laminin a2-deficient muscle cells. Expression of these proteins will be experimentally altered in vivo to determine whether or not they can regulate the survival of laminin u2-deficient muscle and if disease progression can be modulated at different stages by altering their levels. These results will further our understanding of mechanisms controlling the apoptotic process during laminin a2-deficient muscle degeneration and possibly identify pathways that could serve as targets for therapeutic intervention in the treatment of human MCMD.

描述（由申请人提供）：先天性肌营养不良症通常是由肌纤维周围基底膜层粘连蛋白a2（肌球蛋白）表达不足引起的。缺裂素型先天性肌营养不良症（MCMD）的特征是出生后不久就出现严重的肌无力，其改善不足以使患者能够进行正常的步行运动。dy突变小鼠系也缺乏正常的层粘连蛋白u2表达，并为这种疾病提供了实验模型。严重的突变体，如dyw菌株经历肌纤维变性，然后再生，但这些纤维在涉及细胞凋亡的过程中死亡。最终小鼠在4个月内死亡。我们已经发现，肌肉特异性过表达Bcl-2（细胞凋亡抑制剂）可以显著延长存活dyw小鼠并改善断奶后生长，因此表明肌肉细胞中特异性细胞死亡的调节对这种疾病进展具有显著影响。此外，我们发现Bax（一种相关的促凋亡蛋白）缺陷的d/v动物表现出更长的寿命和生长沿着减少的与层粘连蛋白α 2缺陷髓鞘形成缺陷相关的后肢瘫痪。提出实验进一步探索Bcl-2和Bax在层粘连蛋白a2缺陷肌肉病理学进展中的作用，并确定它们在疾病早期和晚期对细胞凋亡、再生和存活的影响。我们还将研究其他凋亡调控分子的表达，特别是FLIPL，ARC，XIAP和Apaf-1，在正常和层粘连蛋白α 2缺陷的肌肉细胞。这些蛋白质的表达将在体内实验性改变，以确定它们是否可以调节层粘连蛋白u2缺陷肌肉的存活，以及是否可以通过改变它们的水平在不同阶段调节疾病进展。这些结果将进一步了解层粘连蛋白α 2缺陷性肌肉变性过程中控制细胞凋亡过程的机制，并可能确定可作为人类MCMD治疗干预靶点的途径。