Dilated cardiomyopathy (DCM) is characterized by cardiac dilation and systolic dysfunction. So far sixteen genes have been shown to cause autosomal dominant familial dilated cardiomyopathy (FDC). We identified a large Korean family from the Jeju island showing a clear Mendelian inheritance of FDC. A genomewide linkage scan at 9 cM marker density identified a peak multipoint LOD score of 2.82 at D1S195. Haplotyping of the region with 15 additional markers defined a candidate interval that included a known candidate gene encoding the lamin A/C (LMNA). Sequencing of the LMNA exons revealed one missense mutation at C568T (Arg190Trp) in the alpha-helical rod domain of the LMNA gene cosegregating with FDC with conduction-system disease. The same mutation was found in patients of another Korean family with FDC without conduction-system disease. Upon screening 14 sporadic DCM cases, we found three LMNA mutations including a case having a previously described (Glu161Lys) mutation and two having novel mutations (Glu53Val and Glu186Lys). Our results suggest that variable genotypes of laminopathy are implicated in not only familial but also considerable proportion of sporadic DCM.
Pedigree ; Mutation/genetics ; Molecular Sequence Data ; Male ; Lamins/classification/*genetics ; Korea ; Humans ; Genetic Predisposition to Disease ; Female ; Cardiomyopathy, Dilated/*genetics/*pathology ; Base Sequence ; Amino Acid Sequence ; Adult

BACKGROUNDMutations in the lamin A/C gene (LMNA) may cause familial dilated cardiomyopathy (dilated cardiomyopathy) characterized by early onset atrio-ventricular block (A-V block) before the manifestation of dilated cardiomyopathy and high risk of sudden death due to ventricular arrhythmia, which is very similar to the phenotype of gap junction related heart disease. This study aimed to determine the expression and localization of connexins in neonatal myocytes transfected with wild-type (WT) or mutant LMNA to elucidate how these mutations cause heart diseases.

METHODSWe studied the connexin 43 (Cx43) and connexin 40 (Cx40) expression in cultured neonatal myocytes transfected with wild-type (WT) or mutant LMNA (Glu82Lys (E82K) and Arg644Cys (R644C)) using confocal imaging and Western blotting analysis.

RESULTSCx43 protein expression was reduced by 40% in cells transfected with LMNA E82K than that in cells transfected with WT LMNA cDNA. Confocal imaging showed that the Cx43 located inside the cells by LMNA E82K. By contrast, LMNA E82K mutation had no effect on expression and localization of Cx40. LMNA R644C transfection did not show any significant effects on gap junctions at all.

CONCLUSIONSOur findings suggest that LMNA E82K significantly reduced the Cx43 expression and altered its localization which may be one of the pathological mechanisms underlying LMNA-related heart disease.

Animals ; Atrioventricular Node ; pathology ; Blotting, Western ; Cardiomyopathy, Dilated ; metabolism ; pathology ; Cells, Cultured ; Connexin 43 ; metabolism ; Connexins ; metabolism ; Fluorescent Antibody Technique ; Gap Junctions ; metabolism ; Humans ; Lamin Type A ; genetics ; physiology ; Mutation ; Rats ; Transfection

OBJECTIVETo explore the role of interleukin-17 (IL-17) in the evolution of viral myocarditis (VMC) into dilated cardiomyopathy (DCM).

METHODSA mouse model of VMC was established in 100 male Balb/c mice by intraperitoneal injection of coxsackievirus B3. The expression of IL-17 protein in the cardiac tissue of the mice was detected immunohistochemically, and IL-17 mRNA in the splenocytes was examined by reverse transcription-polymerase chain reaction (RT-PCR). IL-17 levels in the plasma, peripheral blood mononuclear cell (PBMC) culture supernatants, and phytohemagglutinin (PHA)-stimulated PBMC culture supernatants were measured in 30 DCM patients, 26 non-DCM patients and 20 normal adults using enzyme-linked immunosorbent assay (ELISA), and IL-17 mRNA expression in the PBMCs was detected using RT-PCR.

RESULTSThe levels of IL-17 mRNA in the splenocytes of the mice with VMC were significantly higher at 4 and 6 weeks than those at 8 weeks (P<0.01), but not detected at 2 weeks. No IL-17 expression was found in the ventricular tissue of the mice at 2 weeks, but peaked at 4 weeks followed by gradual decrease (P<0.01). IL-17 level in PHA-stimulated PBMC culture supernatants but not the plasma, and its mRNA level in PHA-stimulated PBMCs but not the PBMC culture supernatants, were significantly elevated in DCM patients as compared with those in non-DCM patients and normal control subjects.

CONCLUSIONSThe mouse model of VMC in the chronic phase and DCM patients express high levels of IL-17, which may contribute to the transition from VMC to DCM.

Adult ; Animals ; Cardiomyopathy, Dilated ; etiology ; metabolism ; pathology ; Coxsackievirus Infections ; complications ; metabolism ; Enterovirus B, Human ; Female ; Humans ; Interleukin-17 ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Middle Aged ; Myocarditis ; complications ; metabolism ; virology ; RNA, Messenger ; genetics ; metabolism