Nuclear Factor-κB Pathway Mediates the Molecular Pathogenesis of LMNA-Related Muscular Dystrophies

LMNA -related muscular dystrophies are caused by mutations of the LMNA gene. Inflammatory changes and cellular apoptosis are significant pathological findings in the muscle cells of these patients. We aimed to investigate the roles of nuclear factor-κB (NF-κB) mediated inflammation as a molecular mechanism for the pathogenesis of LMNA -related muscular dystrophies. Muscle specimen of a patient with LMNA gene mutation (c.1117A>G, p.I373V, reported in our previous work) showed significant inflammatory changes. The ultrastructure of muscle cells showed severe nuclear abnormalities compared with the control. Therefore, we used this mutation to establish mutant cell line for in vitro studies. Transfected human embryonic kidney 293 (HEK293) cells containing a mutant construct from this patient showed irregular nuclear morphology. Mass spectrometry analysis suggested genomic instability and augmented expression of apoptosis-related genes. We detected activation of NF-κB pathway in LMNA mutant cells which promoted the expression of downstream inflammatory factors. The LMNA mutation also activated the molecular pathway of apoptosis in LMNA mutant cells. These are important molecular mechanisms underlying the pathogenesis of LMNA -related muscular dystrophies. Our research provides crucial evidence for future pathogenetic studies and possible treatment strategies for LMNA -related muscular dystrophies.