The Modulation Of Hepc1on The Transgenic Mice Of CTnT^R141W

Objective Hepcidin is a hormone mainly expressed in the tissues of liver, which is invovled in the signals of Fe2+in cell. Hepcidin expresses in heart tissue and it is possible to regulate the function of Fe2+, which has been indicated invovled the physiological function of heart and pathogenesis of heart disese. The paper reported the establishment of heart specific Hepcl transgenic mice and analysis of the effect of the gene Hepcl on the deveopment of dilated cardiomyopathy in the cTnTR141w transgenic mice.Methods The expression of Hepcl gene in both hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) mice were analyzed using gene expression microarray of cTnTR92Q and cTnTR141w myocardium and confirmed by reverse transcriptional polymerase chain reaction (RT-PCR). The transgenic vector was constructed by inserting the mouse Hepc1gene into the downstream of a-MHC promoter. The transgenic mice were created by the method of microinjection. The genotype of transgenic mice of cTnTR141W, Hepc1and Hepc1xcTnTR141w was detected by PCR, the expression level of the Hepc1gene was determined by RT-PCR and slot blotting. Pathologic changes were observed by light microscopy and transmission electronic microscopy. The cardiac structure and function were analyzed with M-mode echocardiography. Survival data of the experimental mice were recorded. The cardiac hypertrophic marker genes were analyzed by RT-PCR and western blotting. The accumulation of p-ERKl/2and ERK1/2were determined by western blotting in wild type, cTnTR141w, Hepcl xcTnTR141w and Hepcl transgenic mice. The expression construct for Hepcl was generated by cloning a PCR-amplified full-length cDNA fragment into pcDNA3.1+vector. H9c2cell line was transfected with Hepc1construct using Lipofectamine2000. The expression level of p-ERK1/2and ERK1/2were also detected in H9c2, DFO-treated H9c2, CMV-Hepcl and FAC-treated CMV-Hepcl cell lines.Results Gene expression microarray analysis, RT-PCR and slot blotting revealed that a lower expression of Hepc1in both DCM mice and HCM mice. C57BL/6J transgenic mice carrying the Hepc1, HepclxcTnTR141w and cTnTR141w genes were all established. The heart of Hepc1transgenic mice showed hypertrophic ventricular wall, reduced ventricular chamber, diastolic dysfunction compared with that of wild type. Thicker myofiber and more mitochondrias of the Hepcl transgenic mice were observed under the transmission electronic microscope. All the pathological changes of Hepcl transgenic mice display light left ventricular hypertrophy. The Hepcl×cTnTR141w transgenic mice showed a thicker ventricular wall, smaller ventricular chamber, improved diastolic function, elongated and lysed myofrils when compared with cTnTR141w transgenic mice. The genes of extracellular matrix protein Col1al, the genes of cytoskeletal protein Actal, were significantly decreased in Hepc1and Hepcl xcTnTR141w transgenic mice, which were increased in cTnTR141w transgenic mice. The gene of calcium-regulation protein ATP2A2was shown to be increased in Hepc1and Hepc1×cTnTR141w transgenic mice,which were decreased in cTnTR141w transgenic mice. Immature death occurred after4months of age and the immature death rate was16%before6months of age in the cTnTR141w mice, while HepclxcTnTR141w transgenic mice showed a low immature death compared with that of cTnTR141w transgenic mice, but higher than that of WT mice. An accumulation of p-ERKl/2was seen both DFO-treated H9c2and CMV-Hepcl cell lines compared with H9c2cell line and FAC-treated CMV-Hepc1cell line. ERK1/2phosphorylation was increased in Hepcl and Hepcl×cTnTR141w transgenic mice compared with cTnTR141w transgenic mice.Conclusions Two heart specific Hepcl transgenic mice lines were established. The Hepcl transgenic mice exihibited an marked improvement on the pathologic phenotype of the cTnTR141w transgenic mice. Hepcl downregulated the iron level in heart tissue, and induced the activation of ERK1/2. These data indicates Hepc1delays the pathophysiological process by downregulation of iron in the heart tissue and it may be a new target in the treatment of dilated cardiomyopathy. Objectives To generate the heart-specific Lrp2bp overexpressing mice, a model for the study of its function and effects on cardiomyopathy.Methods The transgenic vector was constructed by inserting the murine Lrp2bp gene into the downstream of a-MHC promoter. The transgenic mice were created by the method of microinjection. The genotype of transgenic line was identified by PCR and the expression level of the gene was determined by Western blotting. The cardiac function and geometry were detected by echocaridiography. The uLtrastructure changes of cardiomyocytes from Lrp2bp tg mice were observed by transmission electron microsopy.ResuLts Three lines of C57BL/6J transgenic mice with high level of Lrp2bp expression were identified from four transgenic founders. The heart of1-month-old Lrp2bp transgenic mice showed signficantly increased ventricuLar wall, dilated ventricuLar chamber compared with that of wild type whereas ejection fraction (EF%) and fractionl shortening (FS%) were markedly decreased.Conclusions The transgenic mice with cardiac-specific expression of the murine Lrp2bp gene were establised successfuLly and it can be used to crossbreed with the DCM and the HCM models to investigate the function of Lrp2bp gene on the development of caridomyopathy.