Analysis Of Downstream Genes For LMNA Mutations In Dilated Cardiomyopathy

Lamin A is the structural component of nuclear lamina,and plays a role of scaffold and structural in the nuclear inner membrane.The LMNA gene encoding lamin A is located on chromosome 1 and includes 12 exons,and mainly encoding Lamin A and Lamin C.Mutations in LMNA gene has been found to cause a variety of diseases which affecting the striated muscle tissue,surrounding nerve and adipose tissue.Furthermore,some mutations even lead to severe phenotypic changes by affecting several tissues.The effects caused by LMNA mutations mainly include changes in nuclear structure,abnormal localization and expression of interacting proteins,activation of various cell signaling pathways and alterations in gene expression.At present,the pathogenesis of LMNA gene mutation is not fully understood,and the molecular mechanism of different mutations is not exactly the same.In the previous work,a de novo LMNA gene mutation was identified in a family of dilated cardiomyopathy with atrioventricular block.The mutation was located at the end of intron 9 and the mutated LMNA lacked of exon 10.To explore the alterations in gene expression and pathogenesis caused by this mutation,the following experiments were performed:（1）RNA sequencing of HEK-293-TSA cells after transfection with LMNA wild and mutant plasmids;（2）The differentially expressed genes were analyzed and verified at the cell level.The results of RNA sequencing indicated that there were 52differentially expressed genes,among which 6 up-regulated and 46 down-regulated,and35 genes encoding protein were up-regulated by 2 and down-regulated by 33.After screening according to the two parameters of fold change and significance level,25differentially expressed genes were verified by qRT-PCR,and it was confirmed that XPO1was down-regulated at both mRNA and protein levels.In addition,the other 3 reported LMNA mutations leading to heart disease also resulted in down-regulation of XPO1protein level,but the most significant was LMNA^E82K.After treatment with XPO1 inhibitor,cell apoptosis was promoted,which is consistent with the pathogenesis of LMNA^E82K82K promoting apoptosis.In conclusion,in this research,it was found that XPO1 may be a downstream gene affected by LMNA mutation and involved in the pathogenesis of dilated cardiomyopathy.The expression of XPO1 may be involved in the occurrence of disease by affecting apoptosis,and the exact molecular mechanism remains to be further explored.