OBJECTIVETo study cardiac troponin T (TNNT2) gene mutations in Chinese patients with hypertrophic cardiomyopathy (HCM) and analyze the correlation between the genotype and phenotype.

METHODSNinety-five unrelated Chinese patients with HCM and 120 control individuals were screened for TNNT2 gene mutations. Seven exons (8, 9, 10, 11, 14, 15, and 16) in the functional regions of TNNT2 gene were amplified using PCR and the products were sequenced. The patients with positive results underwent further family screening.

RESULTS AND CONCLUSIONThis study did not find any HCM-caused mutations in TNNT2 gene, a result different from the reported rates of TNNT2 gene mutation ranging from 10% to 20% in other nations, suggesting that TNNT2 gene is not a susceptible gene for HCM in Chinese population.

Asian Continental Ancestry Group ; genetics ; Cardiomyopathy, Hypertrophic ; genetics ; Case-Control Studies ; Humans ; Mutation ; Troponin T ; genetics

Cardiomyopathy, Hypertrophic ; epidemiology ; genetics ; China ; epidemiology ; Humans ; Mutation ; Prevalence ; Troponin T ; genetics

Hypertrophic cardiomyopathy (HCM) is the most common monogenic inherited myocardial disease in children, and mutations in sarcomere genes (such as MYH7 and MYBPC3) are the most common genetic etiology of HCM, among which mutations in the MYH7 gene are the most common and account for 30%-50%. MYH7 gene mutations have the characteristics of being affected by environmental factors, coexisting with multiple genetic variations, and age-dependent penetrance, which leads to different or overlapping clinical phenotypes in children, including various cardiomyopathies and skeletal myopathies. At present, the pathogenesis, course, and prognosis of HCM caused by MYH7 gene mutations in children remain unclear. This article summarizes the possible pathogenesis, clinical phenotype, and treatment of HCM caused by MYH7 gene mutations, in order to facilitate the accurate prognostic evaluation and individualized management and treatment of the children with this disorder.
Child ; Humans ; Cardiomyopathy, Hypertrophic/therapy* ; Phenotype ; Troponin T/genetics* ; Mutation ; Carrier Proteins/genetics* ; Myosin Heavy Chains/genetics* ; Cardiac Myosins/genetics*

AIMTo analyze the distribution of single nucleotide polymorphisms in Han ethnic population from Northern China.

METHODSAllele frequencies in a sample of healthy Chinese Hans (n = 204) were determined by polymerase chain reactions followed by restriction analyses with specific endonucleases.

RESULTSThe SNP 27916722 A/C in exon 11 from the NCBI database was not detected in this population. And there were significant differences between the allele frequencies of the SNPs (27930097 C/G and 27920978 C/T) in Han ethnic population from Northern China and those in the NCBI.

CONCLUSIONIt is suggested that the SNPs of sTnT are different in different ethnic populations.

Adolescent ; Adult ; Ethnic Groups ; genetics ; Exons ; Female ; Gene Frequency ; Genotype ; Humans ; Male ; Polymorphism, Single Nucleotide ; Troponin T ; classification ; genetics

Adolescent ; Adult ; Aged ; Cardiomyopathy, Hypertrophic ; genetics ; Child ; Child, Preschool ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Troponin T ; genetics

Cardiac troponin T (cTnT) serves as a structural protein of myocardial fiber, and participates in heart excitation-contraction coupling process. Here, we generated tnnt2a (cTnT-coding gene) deletion mutant zebrafish via CRISPR/Cas9 technique, and performed phenotypic analysis of the identified tnnt2a mutants. We observed that there was no significant difference between heterozygous mutant and wild type zebrafish, and the homozygous mutants displayed significant malformations in heart, including cardiac arrest, atrium and ventricle enlargement, pericardium effusion, and the individuals usually died before 7 day post fertilization (dpf). We further analyzed the expression alternations of heart sarcomere genes (tnnt2a, actc1a, tpm4a, myl7, vmhc) at transcriptional level in tnnt2a(Δ2) zebrafish by performing real time RT-PCR, and found that the RNA expression level of tnnt2a in tnnt2azebrafish decreased constantly at each time point of developmental stages, and actc1a, tpm4a, myl7 and vmhc all showed higher expressions at early developmental stages and lower expressions at late developmental stages, in comparison with those of wild type zebrafish. Lastly, electron microscopy on cardiac tissues suggested that there were significant changes of the thick or thin filament structures in tnnt2a(Δ2) zebrafish, which was further confirmed by F-actin and Tpm4 immunofluorescence staining. The tnnt2azebrafish generated by CRISPR/Cas9 bears the most common symptoms of patients with dilated cardiomyopathy, and therefore can be used as a tool to study TNNT2-deficiency related cardiomyopathy.
Animals ; CRISPR-Cas Systems ; Disease Models, Animal ; Gene Knockout Techniques ; Myocardium ; pathology ; Sequence Deletion ; Troponin T ; genetics ; Zebrafish ; Zebrafish Proteins ; genetics

OBJECTIVEThe aim of this study was to screen the disease-causing gene mutations and investigate the genotype-phenotype correlation in 10 Chinese pedigrees with familial hypertrophic cardiomyopathy (HCM).

METHODSThere are 91 family members from these 10 pedigrees and 5 members were normal mutated carriers, 23 members were HCM patients (14 male) aged from 1.5 to 73 years old. The functional regions of myosin heavy chain gene (MYH7), cardiac myosin-binding protein C (MYBPC3) and cardiac troponin T gene (TNNT2) were screened with PCR and direct sequencing technique. Clinical information from all patients was also evaluated in regard to the genotype.

RESULTSMutations were found in 5 out of 10 pedigrees. Mutations in MYH7 (Arg663His, Glu924Lys and Ile736Thr) were found in 3 pedigrees and 3 patients from these pedigrees suffered sudden death at age 20-48 years old during sport. Mutations in MYBPC3 were found in 2 pedigrees, 1 with complex mutation (Arg502Trp and splicing mutation IVS27 + 12C > T) and 1 with novel frame shift mutation (Gly347fs) and the latter pedigree has sudden death history. No mutation was identified in TNNT2.

CONCLUSIONSAlthough the Han Chinese is a relatively homogeneous ethnic group, different HCM gene mutations were responsible for familiar HCM suggesting the heterogeneity nature of the disease-causing genes and HCM MYH7 mutations are associated with a higher risk of sudden death in this cohort. Furthermore, identical mutation might result in different phenotypes suggesting that multiple factors might be involved in the pathogenesis of familiar HCM.

Adolescent ; Adult ; Aged ; Asian Continental Ancestry Group ; genetics ; Cardiac Myosins ; genetics ; Cardiomyopathy, Hypertrophic, Familial ; ethnology ; genetics ; Carrier Proteins ; genetics ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Middle Aged ; Mutation ; Myosin Heavy Chains ; genetics ; Pedigree ; Phenotype ; Troponin T ; genetics ; Young Adult

OBJECTIVETo investigate the expression of Junctophilin 1 (JP1) in cardiogenesis of mammalian.

METHODSCardiac differentiation of embryonic stem cells (ESCs) was generated by hanging drop method. Fetal heart was obtained from the rats aged d 14-20 of gestation. The expression of JP1 and JP2 during cardiogenesis of ESCs and rat embryos was analyzed by RT-PCR or Western blotting. Immunofluorescence staining was employed to reveal the distribution of JP1 and JP2 in embryoid body (EB), probing for merging of JP1 and JP2 and cardiac sarcomeric α-Actinin or Troponin-T. Percentage of JP1 and JP2-positive staining cells was analyzed quantitatively by FCS on d17.

RESULTSJP1 mRNA was up-regulated at the early stage (d 5-11) and then decreased. The expression of JP1 protein was up-regulated at the early stage (d 7-9), then decreased gradually and disappeared after d 15. While JP2 gene and protein expression increased in a time-dependent manner during cardiogenesis of rat embryos. The results of immunofluorescence staining showed that there was a parallel co-localization of JP2 with Troponin-T or α-Actinin on d17, while JP1 failed to express in the sarcomeric positive area at the same time point. Furthermore, FCS analysis showed that about 16.59% of cells were JP2-positive, while no cells were stained positively for JP1 in d17 EBs.

CONCLUSIONJP1 gene is expressed during the whole process of cardiogenesis, while JP1 protein only appears on the early stage. The expression of JP1 in cardiogenesis of ESCs is consistent with that of rat embryos.

Actinin ; genetics ; metabolism ; Animals ; Cell Differentiation ; Cell Line ; Embryonic Stem Cells ; cytology ; metabolism ; Heart ; embryology ; Membrane Proteins ; genetics ; metabolism ; Mice ; Mice, Inbred ICR ; Myocytes, Cardiac ; cytology ; metabolism ; RNA, Messenger ; genetics ; Rats ; Troponin T ; genetics ; metabolism

OBJECTIVETo investigate the protective effects of c-jun antisense gene recombinant transfection on rat cardiomyocytes inflicted by hypoxia and burn serum.

METHODSCardiomyocytes from Wistar rat were isolated and cultured before being divided into normal control (C), transfection (T) and non-transfection (NT) groups. C-jun antisense gene recombinant was constructed and transfected into cardiomyocytes, which were then treated by hypoxia and burn serum in T group, while those in NT group were simply treated by hypoxia and burn serum. The changes in the c-jun mRNA expression were determined by RT-PCR at 1, 3 and 7 hours after the cardiomyocytes being stimulated, and the changes in the expressions of c-jun protein, troponin-T (TnT) and beta-tubulin were assayed by Western blot. The morphological changes in the cardiomyocytes were observed by LM and EM.

RESULTS1) The expressions of c-jun mRNA and protein in the NT group were increased evidently when compared with those in C and T groups. 2) The expressions of TnT and beta-tubulin in NT group were decreased evidently in contrast to those in C and T groups. In addition, there exhibited evident structural derangement, dissolution and fragmentation to granules of cardiomyocytes in NT group, while the myocardial cytoskeletal structure was well preserved with scarce fragmentation and dissolution in T group.

CONCLUSIONIncreased expression of c-jun in rat cardiomyocytes resulting in myocardial injury could be induced by combined treatment of hypoxia and burn serum, while c-jun antisense gene recombinant transfection might protect rat cardiomyocytes from injury.

Animals ; Burns ; blood ; complications ; genetics ; Cells, Cultured ; Hypoxia ; blood ; complications ; genetics ; Myocytes, Cardiac ; metabolism ; Proto-Oncogene Proteins c-jun ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Transfection ; Troponin T ; metabolism ; Tubulin ; metabolism

OBJECTIVETo clone a novel gene relative to blood glucose regulation.

METHODSRat modes of autonomous regulation of blood glucose was made by intra jugular vein to right atrium injection of high concentration of glucose solution, and the control rats were injected with 0.9%NaCl both before skeletal muscles were separated for gene analysis. The differentially expressed fragments were identified by differential display technology (DDRT-PCR). After slot blot and Northern blot analysis, the artificial positive fragments were excluded and the true EST (expression sequence tag) differentially expressed was obtained. These positive EST were used as probes to screen cDNA library of rat skeletal muscle.

RESULTSA novel full-length cDNA, named as Fang-2 was obtained. GenBank Accession No. was AF399874. Fang-2 was found rat homologue of human troponin T by blast software (NCBI). It shared 78% identical nucleotides, which showed the family proteins were conservative. After high concentration of glucose stimulation of rats, the expression of Fang-2 was down-regulated.

CONCLUSIONSA novel gene relative to blood glucose regulation was cloned from rat skeletal muscle. The gene can regulate blood glucose level by effect certain mechanisms unknown yet with down-regulation expression.

Amino Acid Sequence ; Animals ; Base Sequence ; Blood Glucose ; metabolism ; Cloning, Molecular ; DNA, Complementary ; isolation & purification ; Gene Expression Profiling ; Male ; Models, Animal ; Molecular Sequence Data ; Muscle, Skeletal ; metabolism ; Rats ; Rats, Sprague-Dawley ; Troponin T ; genetics