ACTC1 Research Articles

Exome sequencing data reanalysis of 200 hypertrophic cardiomyopathy patients: the HYPERGEN French cohort 5 years after the initial analysis.

Approximately half of hypertrophic cardiomyopathy (HCM) patients lack a precise genetic diagnosis. The likelihood of identifying clinically relevant variants increased over time. In this study, we conducted a gene-centric reanalysis of exome data of 200 HCM cases 5 years after the initial analysis. This reanalysis prioritized genes with a matched HCM entry in the OMIM database and recently emerging HCM-associated genes gathered using a text mining-based literature review. Further classification of the identified genes and variants was performed using the Clinical Genome Resource (ClinGen) resource and American College of Medical Genetics and Genomics (ACMG) guidelines to assess the robustness of gene-disease association and the clinical actionability of the prioritized variants. As expected, the majority of patients carried variants in MYBPC3 and MYH7 genes, 26% (n = 51) and 8% (n = 16), respectively, in accordance with the initial analysis. The vast majority of pathogenic (P) and likely pathogenic (LP) variants were found in MYBPC3 (22 out of 40 variants) and MYH7 (8 out of 16 variants) genes. Three genes-not included in the initial analysis-were identified: SVIL, FHOD3, and TRIM63. Considering only patients with unique variants in the last three genes, there was a 9% enhancement in variant identification. Importantly, SVIL variant carriers presented apical and septal HCM, aortopathies, and severe scoliosis for one patient. Ten patients (5%) carried variants in the FHOD3 gene, six in hotspot regions (exons 12 and 15). We identified seven variants within the TRIM63 gene in 12 patients (6%). Homozygous variants were detected in 2.5% of the cohort in MYBPC3 (n = 1), MYL3 (n = 1), and TRIM63 (n = 3) genes. Our study revealed that no variants were found in the ACTC1, TPM1, and TNNI3 genes in the HYPERGEN cohort. However, we identified variants in five out of the eight HCM core genes, with a high prevalence in young patients. We identified variants in three recent HCM-associated genes (SVIL, FHOD3, and TRIM63) in 35 patients, with 18 patients carrying unique variants (9%). Our results further emphasize the usefulness of exome data reanalysis, particularly in genotype-negative patients.

Searching for genetic determinants for left ventricular non-compaction.

Left ventricular non-compaction (LVNC) is still a pathology around which there are numerous controversies regarding the criteria for its diagnosis, presentation, prognosis, and even classification into the appropriate group of diseases. So far, about 190 genes in which mutations may be associated with LVNC have been described, and in each of them, several to several dozen different loci have been discovered. We decided to analyze the frequency of single nucleotide variants (SNVs) in correlation to Petersen's criteria. We retrospectively analyzed the results of cardiac magnetic resonance (CMR) studies. Twenty-three patients who met Petersen's criteria agreed to participate in the research and take blood samples for genetic testing. Next, we prospectively included 24 volunteers who did not meet Petersen's criteria. Petersen's criteria were complied with ratio of non-compacted to compacted myocardium (NC/C) ≥2.3. A total of 47 DNA samples were analyzed based on the selected regions of the following genes: β-myosin heavy chain (MYH7), α-cardiac actin (ACTC1), cardiac troponin T (TNNT2), myosin binding protein-C (MYBPC3), LIM-domain binding protein 3 (LBD3), and taffazin (TAZ). In total, 248 substitutions in exons and introns were obtained for all analyzed samples. No statistically significant differences were detected between the mentioned groups. No significant difference in either downward or upward trends in the number of substitutions in relation to the increasing trabeculation is observed. We indicated differences in the occurrence of the studied SNVs between groups, especially for rs8037241 (3'UTR region of ACTC1) and rs2675686 (LDB3), but they also did not show statistical significance. Although we did not find a significant correlation between the co-occurrence of individual mutations with LVNC, it is worth noting that the presence of one of the four mutations in the range rs8037241 (ACTC1 3'UTR), rs3729998 (TNNT2e. 12), and rs727503240 (MYH7e. 39) increases the risk of LVNC more than 4 times. An inverse association between the number of SNVs and the meeting the Petersen's criteria was demonstrated for studied LDB3 region and rs397516254 in exon 39 of the MYH7 gene. To our knowledge, no studies have been published comparing the prevalence of selected SNVs in a group of healthy subjects and in a group meeting the Petersen criteria for LVNC. Among both completely healthy individuals who did not meet the Petersen criteria for LVNC as well as those with symptoms who met these criteria we found a similar incidence of SNVs in the ACTC1, TNNT2, LDB3 and MYH7 genes segments analyzed. Further studies are required to confirm or exclude "potentially protective" SNV in the 39th exon of MYH7 (rs397516254) and the role of co-occurrence of individual SNVs in rs8037241 (ACTC1 3'UTR), rs3729998 (TNNT2), and rs727503240 (MYH7) for the increase of the risk of LVNC.

Identification of different myofiber types in pigs muscles and construction of regulatory networks

BackgroundSkeletal muscle is composed of muscle fibers with different physiological characteristics, which plays an important role in regulating skeletal muscle metabolism, movement and body homeostasis. The type of skeletal muscle fiber directly affects meat quality. However, the transcriptome and gene interactions between different types of muscle fibers are not well understood.ResultsIn this paper, we selected 180-days-old Large White pigs and found that longissimus dorsi (LD) muscle was dominated by fast-fermenting myofibrils and soleus (SOL) muscle was dominated by slow-oxidizing myofibrils by frozen sections and related mRNA and protein assays. Here, we selected LD muscle and SOL muscle for transcriptomic sequencing, and identified 312 differentially expressed mRNA (DEmRs), 30 differentially expressed miRNA (DEmiRs), 183 differentially expressed lncRNA (DElRs), and 3417 differentially expressed circRNA (DEcRs). The ceRNA network included ssc-miR-378, ssc-miR-378b-3p, ssc-miR-24-3p, XR_308817, XR_308823, SMIM8, MAVS and FOS as multiple core nodes that play important roles in muscle development. Moreover, we found that different members of the miR-10 family expressed differently in oxidized and glycolytic muscle fibers, among which miR-10a-5p was highly expressed in glycolytic muscle fibers (LD) and could target MYBPH gene mRNA. Therefore, we speculate that miR-10a-5p may be involved in the transformation of muscle fiber types by targeting the MYHBP gene. In addition, PPI analysis of differentially expressed mRNA genes showed that ACTC1, ACTG2 and ACTN2 gene had the highest node degree, suggesting that this gene may play a key role in the regulatory network of muscle fiber type determination.ConclusionsWe can conclude that these genes play a key role in regulating muscle fiber type transformation. Our study provides transcriptomic profiles and ceRNA interaction networks for different muscle fiber types in pigs, providing reference for the transformation of pig muscle fiber types and the improvement of meat quality.

The Definition of Sarcomeric and Non-Sarcomeric Gene Mutations in Hypertrophic Cardiomyopathy Patients: A Multicenter Diagnostic Study Across Türkiye.

Hypertrophic cardiomyopathy is a common genetic heart disease and up to 40%-60% of patients have mutations in cardiac sarcomere protein genes. This genetic diagnosis study aimed to detect pathogenic or likely pathogenic sarcomeric and non-sarcomeric gene mutations and to confirm a final molecular diagnosis in patients diagnosed with hypertrophic cardiomyopathy. A total of 392 patients with hypertrophic cardiomyopathy were included in this nationwide multicenter study conducted at 23 centers across Türkiye. All samples were analyzed with a 17-gene hypertrophic cardiomyopathy panel using next-generation sequencing technology. The gene panel includes ACTC1, DES, FLNC, GLA, LAMP2, MYBPC3, MYH7, MYL2, MYL3, PLN, PRKAG2, PTPN11, TNNC1, TNNI3, TNNT2, TPM1, and TTR genes. The next-generation sequencing panel identified positive genetic variants (variants of unknown significance, likely pathogenic or pathogenic) in 12 genes for 121 of 392 samples, including sarcomeric gene mutations in 30.4% (119/392) of samples tested, galactosidase alpha variants in 0.5% (2/392) of samples and TTR variant in 0.025% (1/392). The likely pathogenic or pathogenic variants identified in 69 (57.0%) of 121 positive samples yielded a confirmed molecular diagnosis. The diagnostic yield was 17.1% (15.8% for hypertrophic cardiomyopathy variants) for hypertrophic cardiomyopathy and hypertrophic cardiomyopathy phenocopies and 0.5% for Fabry disease. Our study showed that the distribution of genetic mutations, the prevalence of Fabry disease, and TTR amyloidosis in the Turkish population diagnosed with hypertrophic cardiomyopathy were similar to the other populations, but the percentage of sarcomeric gene mutations was slightly lower.

Overexpression of PYGO1 promotes early cardiac lineage development in human umbilical cord mesenchymal stromal/stem cells by activating the Wnt/β-catenin pathway.

Cardiovascular disease still has the highest mortality. Gene-modified mesenchymal stromal/stem cells could be a promising therapy. Pygo plays an important role in embryonic development and regulates life activities with a variety of regulatory mechanisms. Therefore, this study aimed to investigate whether the overexpression of the PYGO1 gene can promote the differentiation of human umbilical cord-derived mesenchymal stromal/stem cells (HUC-MSCs) into early cardiac lineage cells and to preliminary explore the relevant mechanisms. In this study, HUC-MSCs were isolated by the explant method and were identified by flow cytometry and differentiation assay, followed by transfected with lentivirus carrying the PYGO1 plasmid. In PYGO1 group (cells were incubated with lentiviral-PYGO1), the mRNA expressions of cardiac differentiation-specific markers (MESP1, NKX2.5, GATA4, MEF2C, ISL1, TBX5, TNNT2, ACTC1, and MYH6 genes) and the protein expressions of NKX2.5 and cTnT were significantly up-regulated compared with the NC group (cells were incubated with lentiviral-empty vector). In addition, the proportion of NKX2.5, GATA4, and cTnT immunofluorescence-positive cells increased with the inducement time. Overexpression of PYGO1 statistically significantly increased the relative luciferase expression level of Topflash plasmid, the protein expression level of β-catenin and the mRNA expression level of CYCLIND1. Compared with the control group, decreased protein levels of NKX2.5 and cTnT were detected in PYGO1 group after application of XAV-939, the specific inhibitor of the canonical Wnt/β-catenin pathway. Our study suggests that overexpression of PYGO1 significantly promotes the differentiation of HUC-MSCs into early cardiac lineage cells, which is regulated by the canonical Wnt/β-catenin signaling.

Specific actin (ACTC1) missense variants are associated with different overlapping clinical phenotypes and outcomes

Abstract Introduction Pathogenic variants in ACTC1 have been associated with hypertrophic (HCM), dilated (DCM), and left ventricular non-compaction (LVNC) cardiomyopathies. Phenotypes often overlap and atrial septal defects have also been reported. Prognostic data on carriers of these variants are scarce. Methods and results The proprietary database of a cardiovascular genetic laboratory was examined to assess penetrance and survival in the 438 carriers (191 families) of 75 missense variants in ACTC1 associated with disease. Their mean age at diagnosis was 32.4 (±18.7) years; 52% were male. The diagnosis was isolated HCM in 47%, LVNC in 17%, and DCM in 9%. LVNC with either HCM or DCM was present in an additional 8%; 13% had an atrial septal defect. Among carriers with echocardiographic information, left ventricular dilatation and dysfunction were described in 13% and 16%, respectively. Ventricular arrhythmias and conduction defects were reported in 94 and 93 carriers. Percentages have not been calculated for the latter, as we cannot ensure a denominator in whom cardiac conduction defects and arrhythmias were certainly discarded. Overall, 50% of carriers were diagnosed by age 45, and 10% had experienced a major cardiac event. The p.Leu10Met and p.His90Tyr variants (23% of all carriers) demonstrated lower penetrance and a better prognosis than the p.Glu101Lys variant and the other missense variants. Conclusions Missense variants in ACTC1 are associated with a range of phenotypes that often overlap. Overall, penetrance and outcomes are age-dependent with a moderate rate of major cardiac events, which are highly dependent on the specific disease-causing variant Funding Acknowledgement Type of funding sources: None. Figure 1. The graph shows the percentage of carriers of pathogenic or likely pathogenic missense variants in the ACTC1 gene diagnosed at different ages. Considering all the missense variants in ACTC (in red), 50% of carriers had been diagnosed by age 45. It is worth highlighting the percentage of diagnosis (>15%) in the first 15 years of life, which is higher than the figure usually observed in sarcomeric hypertrophic cardiomyopathy.Figure 2. The graph shows the survival free of major cardiovascular events (sudden, heart failure, stroke-related death, appropriate ICD therapy and heart transplant) in individuals with missense variants in ACTC1. Carriers and affected relatives without genetic study were included. Events were infrequent in two of the most informative variants (p.Leu10Met and p.His90Tyr), and significantly different compared with carriers of the other missense variants (p=0.036 for p.Leu10Met and p=0.015 for p.His90Tyr).

Genotype/Phenotype correlation and prognosis for undescribed ACTC1 missense variants

Abstract Purpose Establish the genotype/phenotype correlation for missense undescribed variants in ACTC1, and evaluate their prognostic implications. Methods A systematic screening for the ACTC1 gene was performed using NGS in 17,683 individuals with inherited cardiovascular disease, 6,984 of them with hypertrophic cardiomyopathy, 3,507 with dilated cardiomyopathy, and 760 left ventricular non-compaction. These phenotypes were clinically diagnosed by each center prior to the genetic study. Frequency of the variants was compared with gene gnomAD and ClinVar databases. A systematic review of the literature was performed to search for previously reported variants. We evaluated available follow up data and constructed Kaplan-Meier survival curves free from cardiovascular death (sudden death, Heart transplant, heart failure death, appropriate ICD discharge and stroke related death). Log-rank test was used to compare event-free survival time between males and females. Results 39 missense variants were identified in 283 carriers (125 index cases; 158 first-degree relatives). Twenty-two have not been previously described or identified in public databases. 17 have been reported in gnomAD or Clinvar. Carriers phenotypes were: 120 HCM; 43 LVNC; 16 DCM; three had cardiac septal defect and two had sudden death. Some of the carriers had overlapped or combined phenotypes: 7 HCM and LVNC, 7 septal defects and LVNC, 3 HCM and septal defects, 4 MCD and LVNC. 24 were healthy carriers, and we have no phenotypic data of the remaining individuals. Family studies were performed in 12 families out of the 22 undescribed variants, showing cosegregation in 8 variants. One case was “de novo”. Interestingly, a rare variant, previously identified as VUS in ClinVar, showed a clearly cosegregation with HCM. The Leu10Met variant with a frequency of 9/282084 alleles in gnomAD (1/15671 individuals) was identified in 20 index cases, which represents 1/884 of all the genotyped (0.11%), and 1/387 patients with HCM (0.35%). We found it in 2/9289 patients with other phenotypes (p<0.001). 51 patients (18%) presented an event during follow up. In several cases, carriers developed early atrial fibrillation. The survival curve shows adverse events from the first decade of life, with a 10% cumulative rate of events at age 40, 80% survival at age 60, and a 60% survival at age 70. No significant differences in the incidence of cardiovascular death between men and women were observed. Conclusion HCM is the most frequent phenotype in carriers of ACTC1 variants, followed by LVNC, and DCM. Septal defects are not rare, and they are usually described in combination with cardiomyopathies. Disease course seems to have a good prognosis. Sudden death is an exception at early ages and appears to be associated with severe morphological expression. Given the presence of cosegregation with disease in rare variants, many of the ACTC1 variants may have an incomplete penetrance, and late disease expression. ACTC1 Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Health in Code

The Dark Side of Actin: Cardiac actin variants highlight the role of allostery in disease development

Mutations in the α-cardiac actin ACTC1 gene cause dilated or hypertrophic cardiomyopathy. These diseases are the result of changes in protein interactions between ACTC protein and force-generating β-myosin or the calcium-dependent cardiac-tropomyosin (cTm) and cardiac troponin (cTn) regulatory complex, altering the overall contractile force. The T126I and S271F ACTC variants possess amino acid substitutions on the other side of actin relative to the myosin or regulatory protein binding sites on what we call the “dark side” of actin. The T126I change results in hyposensitivity to calcium, in accordance with the calcium sensitivity pathway of cardiomyopathy development while the S271F change alters the maximum in vitro motility sliding speed, reflecting a change in maximum force. These results demonstrate the role of actin allostery in the cardiac disease development.

Comprehensive analysis reveals a six-gene signature and associated drugs in mimic inguinal hernia model.

Inguinal hernia often occurs in elderly men, and more than one in five men will undergo inguinal hernia repair during their lifetime. Nevertheless, the underlying molecular mechanisms of the pathogenesis behind hernia formation is still unclear. The aims in this study are finding out the potential gene markers and available drugs. Firstly, we re-analyzed the GSE92748 datasets, including four high and four low expressions of humanized aromatase transgenic mice, which refers to mimic humanized hernia, to identify differentially expressed genes (DEGs) in AromhumH group compared with AromhumL group by the criteria: fold change ≥ 1.4 and adjust P value < 0.05. Secondly, the gene ontology and signaling pathway enrichment analyses of these DEGs were performed through online databases. In addition to the protein and protein interaction networks among these DEGs were constructed and the significant gene modules were chosen for further gene-drug interaction analysis. Lastly, the existing drugs target to these module genes were screen to explore the therapeutic effect for treatment of hernia. We have identified 64 DEGs, which were associated with muscle system process, actomyosin structure organization etc. Moreover, the significant module genes in PPI networks were Cmya1, Casq2, Cmya5, Ttn, Csrp3 and Actc1, and one existing drug, DEXAMETHASONE, have targeted to Actc1 gene. In the paper, we identified 6 potential genes and one existing drug for inguinal hernia, which might be used as targets and drugs for the study of inguinal hernia.

Inhibition of myostatin prevents microgravity-induced loss of skeletal muscle mass and strength.

The microgravity conditions of prolonged spaceflight are known to result in skeletal muscle atrophy that leads to diminished functional performance. To assess if inhibition of the growth factor myostatin has potential to reverse these effects, mice were treated with a myostatin antibody while housed on the International Space Station. Grip strength of ground control mice increased 3.1% compared to baseline values over the 6 weeks of the study, whereas grip strength measured for the first time in space showed flight animals to be -7.8% decreased in strength compared to baseline values. Control mice in space exhibited, compared to ground-based controls, a smaller increase in DEXA-measured muscle mass (+3.9% vs +5.6% respectively) although the difference was not significant. All individual flight limb muscles analyzed (except for the EDL) weighed significantly less than their ground counterparts at the study end (range -4.4% to -28.4%). Treatment with myostatin antibody YN41 was able to prevent many of these space-induced muscle changes. YN41 was able to block the reduction in muscle grip strength caused by spaceflight and was able to significantly increase the weight of all muscles of flight mice (apart from the EDL). Muscles of YN41-treated flight mice weighed as much as muscles from Ground IgG mice, with the exception of the soleus, demonstrating the ability to prevent spaceflight-induced atrophy. Muscle gene expression analysis demonstrated significant effects of microgravity and myostatin inhibition on many genes. Gamt and Actc1 gene expression was modulated by microgravity and YN41 in opposing directions. Myostatin inhibition did not overcome the significant reduction of microgravity on femoral BMD nor did it increase femoral or vertebral BMD in ground control mice. In summary, myostatin inhibition may be an effective countermeasure to detrimental consequences of skeletal muscle under microgravity conditions.

Syndrome of Primary Myocardial Hypertrophy: Clinical and Morphological, Genetic Diagnostics and Comparison of Sarcomerial Variants of Cardiomyopathy and its Phenocopy

Aim. To study the nosological spectrum in the syndrome of primary left ventricle hypertrophy (PLVH) using morphological and genetic diagnostics and to compare the clinical course of true hypertrophic cardiomyopathy (HCM) and its phenocopy.Material and methods. Fifty five adult patients (29 men, 48.2±17.0 years) with PLVH (12 mm and more) were included. The exclusion criteria were athletic heart, hypertensive heart disease, severe valvular disease and other causes of secondary left ventricle (LV) hypertrophy. We performed 11 endomyocardial biopsy, 8 intraoperative biopsy, 1 study of explanted heart, 1 autopsy with virus investigation (real-time polymerase chain reaction) of the blood and myocardium. Mutational screening had included simultaneous sequencing of the MYBPC3, TAZ, TPM1, LDB3, MYL2, ACTC1, MYL3, MYH7, TNNI3 and TNNT2 genes based on NGS technology (Ion Torrent PGMTM) with following Sanger resequencing of potentially significant genetic variants. For patients with a phenotype of particular genetic syndrome the Sanger sequencing of target gene(s) for performed first. Clinical examination had included electrocardiography, Holter monitoring, echocardiography, coronary angiography, computer tomography/magnetic resonance imaging (by indication). The mean follow-up was 8 [3;32] month.Results. Isolated HCM was found in 28 patients, and 10 have a combination of HCM and noncompaction myocardium (NCM). Mutations in the MYH7 and MYBPC3 genes were detected in six cases. In 17 cases (30.9%) the non-sarcomeric causes of LVHS were detected. Three patients had Fabry disease, 2 ‒ had Danon disease, in 10patients we found amyloidoses, in 1 – Friedreich ataxia, and 1 patient was diagnosed with LEOPARD syndrome (all cases were confirmed by DNA diagnostics). Genotype-positive diagnosis was established in 23.6% of patients. In patients with HCM were significantly more frequent asymmetric septal hypertrophy with obstruction and muscle bridges, in other forms of primary hypertrophy – right ventricular hypertrophy, low QRS voltage, QS complexes and increasing of ejection fraction (EF) (55.7±12.5% vs 62.5±10.1% in HCM, p=0.08). The morphologic signs of myocarditis were in 46.7% of patients with HCM detected: in 3 patients with NCM and in 4 patients with isolated HCM. The viral genome in the myocardium was in 11 patients with HCM (73.3%) detected, previously human herpes virus type 6 (it was correlation with myocarditis) and parvovirus B19. Eleven patients died due to a stroke/heart failure without no significant differences between patients with HCM and phenocopy.Conclusion. The spectrum of causes of the primary left ventricular hypertrophy is very wide. The frequency of myocarditis associated with sarcomeric HCM was 46.7%. When lower EF and heart failure in patients with HCM can be result of myocarditis, in patients with storage disease they are the result of disease itself.

Analyses of MicroRNA and mRNA Expression Profiles Reveal the Crucial Interaction Networks and Pathways for Regulation of Chicken Breast Muscle Development.

There is a lack of understanding surrounding the molecular mechanisms involved in the development of chicken skeletal muscle in the late postnatal stage, especially in the regulation of breast muscle development related genes, pathways, miRNAs and other factors. In this study, 12 cDNA libraries and 4 small RNA libraries were constructed from Gushi chicken breast muscle samples from 6, 14, 22, and 30 weeks. A total of 15,508 known transcripts, 25,718 novel transcripts, 388 known miRNAs and 31 novel miRNAs were identified by RNA-seq in breast muscle at the four developmental stages. Through correlation analysis of miRNA and mRNA expression profiles, it was found that 417, 370, 240, 1,418, 496, and 363 negatively correlated miRNA–mRNA pairs of W14 vs. W6, W22 vs. W6, W22 vs. W14, W30 vs. W6, W30 vs. W14, and W30 vs. W22 comparisons, respectively. Based on the annotation analysis of these miRNA–mRNA pairs, we constructed the miRNA–mRNA interaction network related to biological processes, such as muscle cell differentiation, striated muscle tissue development and skeletal muscle cell differentiation. The interaction networks for signaling pathways related to five KEGG pathways (the focal adhesion, ECM-receptor interaction, FoxO signaling, cell cycle, and p53 signaling pathways) and PPI networks were also constructed. We found that ANKRD1, EYA2, JSC, AGT, MYBPC3, MYH11, ACTC1, FHL2, RCAN1, FOS, EGR1, and FOXO3, PTEN, AKT1, GADD45, PLK1, CCNB2, CCNB3 and other genes were the key core nodes of these networks, most of which are targets of miRNAs. The FoxO signaling pathway was in the center of the five pathway-related networks. In the PPI network, there was a clear interaction among PLK1 and CDK1, CCNB2, CDK1, and GADD45B, and CDC45, ORC1 and MCM3 genes. These results increase the understanding for the molecular mechanisms of chicken breast muscle development, and also provide a basis for studying the interactions between genes and miRNAs, as well as the functions of the pathways involved in postnatal developmental regulation of chicken breast muscle.

Novel phenotype–genotype correlations of hypertrophic cardiomyopathy caused by mutation in α-actin and myosin-binding protein genes in three unrelated Chinese families

BackgroundThe correlations between genotype and phenotype in hypertrophic cardiomyopathy (HCM) have not been established. Mutation of α-actin gene (ACTC1) is a rare cause of HCM. This study aimed to explore novel genotype–phenotype correlations in HCM patients with the variants in ACTC1 and myosin-binding protein (MYBPC3) genes in three unrelated Chinese families. MethodsClinical, electrocardiographic, and echocardiographic examinations were performed in three Han pedigrees. Exon and boarding intron analysis of 96 cardio-disease-related genes was performed using second-generation sequencing on three probands. The candidate variants were validated in 14 available family members and 300 unrelated healthy controls by bi-directional Sanger sequencing. The pathogenicity and conservation were calculated using MutationTaster, PolyPhen-2, SIFT, and Clustal X. Pathogenicity classification of the variants was based on American College of Medical Genetics and Genomics (ACMG) guidelines. ResultsNine members fulfilled diagnostic criteria for HCM with clinical characteristics, electrocardiographic, and echocardiographic findings. Two candidate variants in ACTC1 p.Asp26Asn (ACTC1-D26N) and MYBPC3 p.Arg215Cys (MYBPC3-R215C) were identified in patients. Only ACTC1-D26N strongly co-segregated with the HCM phenotype. Seven patients who harbored variant ACTC-D26N only were diagnosed with non-obstructive HCM, and four of these patients exhibited a triphasic left ventricular (LV) filling pattern. Two patients carrying both ACTC1-D26N and MYBPC3-R215C variants showed a higher LV outflow tract pressure gradient. Bioinformatics analysis revealed that the two variants were deleterious and highly conserved across species. According to ACMG guidelines, ACTC1-D26N is classified as a likely pathogenic mutation. The second variation MYBPC3-R215C may function as a genetic modifier, which remains uncertain here. ConclusionsNovel p.(Asp26Asn) mutation of ACTC1 was associated with HCM phenotype, and the penetrance is extremely high (∼81.8%) in adults. The second variation, MYBPC3-R215C may function as a genetic modifier, which remains uncertain here.

Genomic structure and expression of the porcine ACTC1 gene

A partial cDNA (~1200 bp) of the porcine ACTC1 gene was identified in the subtracted foetal hind limb muscle cDNA library (44 days of gestation; using m. biceps femoris cDNA as the driver). Using specific polymerase chain reaction (PCR) primers, a bacterial artificial chromosome (BAC) clone containing the genomic ACTC1 gene was identified and the gene was sequenced. Specific PCR primers designed from the BAC and cDNA sequences were used for amplification and comparative sequencing of ACTC1 of Pietrain and Meishan pigs. The gene is approximately 5.4 kb in length, is composed of 7 exons, and has a coding sequence containing 1134 bp. The gene was mapped using the INRA-Minnesota porcine radiation hybrid (IMpRH) panel to chromosome 1, with SW65 as the closest marker (41 cR; LOD = 7.73). Differences were observed in tissue-specific expression of ACTC1 that was studied by transcription profiling in 28 porcine tissues. Developmental differences in muscle and heart were analysed by real-time quantitative PCR (RT-qPCR). Two single nucleotide polymorphisms (SNPs) were found in intron 1. One adequately informative SNP (FM212567.1:g.901C&amp;gt;G) was genotyped by PCR-restriction fragment length polymorphism, and allele frequencies in eight pig breeds were calculated.

THE URGENCY OF GENETIC VERIFICATION OF NON-COMPACTION CARDIOMYOPATHY IN CHILDREN: CLINICAL CASES

Background. Non-compaction cardiomyopathy is a group of genetically heterogeneous, poorly studied myocardial diseases with a variety of clinical manifestations (from asymptomatic course to progressive systolic dysfunction with symptoms of chronic heart failure, arrhythmias, and thromboembolic complications). Considering the variety of genetic disorders associated with the development of noncompaction cardiomyopathy, genetic verification of the diagnosis is important for determining the prognosis and conducting genetic counselling of families with cases of the disease.Description of the Clinical Case. The article presents two clinical observations of a severe course of non-compaction cardiomyopathy with remodeling of the heart cavities according to the dilated phenotype. In order to clarify the disease etiology, a molecular genetic study was conducted using the method of direct automatic sequencing with the analysis of targeted regions of 404 genes which mutations are described in hereditary diseases of the heart and blood vessels. After verifying the mutation (in the ACTC1 and MYBPC3 genes), we performed a search for the detected nucleotide substitution in the venous blood samples of parents and in one case — in the fetal DNA sample. The mode of inheritance has been determined; the probability of recurrence of the disease in siblings in subsequent pregnancies has been estimated.Conclusion. The description of clinical cases shows the importance of genetic verification of the diagnosis in patients with non-compaction cardiomyopathy for determining the disease prognosis and developing an algorithm for monitoring relatives of a proband.

Cardiogenic effects of characterized Geum urbanum extracts on adipose-derived human mesenchymal stem cells.

Stem cell therapy is considered as a promising treatment for cardiovascular diseases. Adipose-derived mesenchymal stem cells (ADMSCs) have the ability to undergo cardiomyogenesis. Medicinal plants are effective and safe candidates for cell differentiation. Therefore, the aim of our study was to investigate cardiogenic effects of characterized (HPLC-UV) extracts of Geum urbanum on ADMSCs of adipose tissue. The methanolic extracts of the root and aerial parts of G. urbanum were obtained and MTT assay was used for studying their cytotoxic effects. Then, cells were treated with 50 or 100 μg/mL of the extracts from root and aerial parts of G. urbanum. MTT assay showed that the extracts of G. urbanum did not have any toxic effects on ADMSCs. Immunostaining results showed increase in the expression of α-actinin and cardiac troponin I (cTnI), and quantitative real-time reverse-transcription PCR data confirmed the upregulation of ACTN, ACTC1, and TNNI3 genes in ADMSCs after treatment. According to HPLC fingerprinting, some cardiogenic effects of G. urbanum extracts are probably due to ellagic and gallic acid derivatives. Our findings indicated that G. urbanum extracts effectively upregulated some essential cardiogenic markers, which confirmed the therapeutic role of this plant as a traditional cardiac medicine.

Steps toward Maturation of Embryonic Stem Cell-Derived Cardiomyocytes by Defined Physical Signals.

SummaryCardiovascular disease remains a leading cause of mortality and morbidity worldwide. Embryonic stem cell-derived cardiomyocytes (ESC-CMs) may offer significant advances in creating in vitro cardiac tissues for disease modeling, drug testing, and elucidating developmental processes; however, the induction of ESCs to a more adult-like CM phenotype remains challenging. In this study, we developed a bioreactor system to employ pulsatile flow (1.48 mL/min), cyclic strain (5%), and extended culture time to improve the maturation of murine and human ESC-CMs. Dynamically-cultured ESC-CMs showed an increased expression of cardiac-associated proteins and genes, cardiac ion channel genes, as well as increased SERCA activity and a Raman fingerprint with the presence of maturation-associated peaks similar to primary CMs. We present a bioreactor platform that can serve as a foundation for the development of human-based cardiac in vitro models to verify drug candidates, and facilitates the study of cardiovascular development and disease.

Proteomic analysis of retinal proteins in rabbits following intravitreal PBS injection: analysis with tandem mass tag labeling coupled with LC-MS/MS.

Intravitreal (IVT) injection has become one of the most commonly performed ophthalmologic procedures. We investigated the changes in retinal function and proteomics in rabbits receiving IVT injection of PBS to evaluate the safety of IVT injection. Twenty Chinchilla rabbits were subjected to IVT injection of 50 µL PBS in the right eyes. On days 0, 4, 7 and day 14, the retinas of the rabbits were isolated after routine ophthalmic and electroretinogram examinations. The protein expressions in the retinas were quantified using tandem mass tag (TMT)-labeling coupled with LC-MS/MS, and bioinformatic analysis of the differentially expressed proteins (DEPs) was performed based on KEGG database to identify significantly enriched pathways. Functional network of the significant DEPs was analyzed using STRING. No noticeable fundus or functional changes occurred in the rabbit eyes following IVT injection of PBS. A total of 6042 retinal proteins were identified in the retina following the injection, among which 49 proteins (0.81%) exhibited over 5.0-fold up-regulation or over 80% down- regulation relative to the control. Most of the distinctly up-regulated or down-regulated proteins were associated with the cytoskeleton. Significantly enriched pathways involved focal adhesion, tight junction, riboflavin metabolism, extracellular matrix-receptor interaction and regulation of actin cytoskeleton. Functional network analysis showed that ACTC1 and ISG15 played central roles in the protein interaction networks. IVT PBS injection in rabbits causes alterations in proteins associated with cell adhesion, morphology, migration, differentiation, signal transduction and riboflavin metabolism, but the alterations of the retinal proteins appear not sufficient to cause observable pathology of the retina.

Congenital heart defects are rarely caused by mutations in cardiac and smooth muscle actin genes.

Background. Congenital heart defects (CHDs) often have genetic background due to missense mutations in cardiomyocyte-specific genes. For example, cardiac actin was shown to be involved in pathogenesis of cardiac septum defects and smooth muscle actin in pathogenesis of aortic aneurysm in combination with patent ductus arteriosus (PDA). In the present study, we further searched for mutations in human α-cardiac actin (ACTC1) and smooth muscle α-actin (ACTA2) genes as a possible cause of atrial septum defect type II (ASDII) and PDA. Findings. Total genomic DNA was extracted from peripheral blood of 86 individuals with ASDs and 100 individuals with PDA. Coding exons and flanking intron regions of ACTC1 (NM_005159.4) and ACTA2 (NM_001613) were amplified by PCR with specific primers designed according to the corresponding gene reference sequences. PCR fragments were directly sequenced and analyzed. Sequence analysis of ACTC1 and ACTA2 did not identify any nucleotide changes that altered the coding sense of the genes. In ACTC1 gene, we were able to detect one previously described nucleotide polymorphism (rs2307493) resulting in a synonymous substitution. The frequency of this SNP was similar in the study and control group, thus excluding it from the possible disease-associated variants. Conclusions. Our results confirmed that the mutations in ACTC1 gene are rare (at least <1%) cause of ASDII. Mutations in ACTA2 gene were not detected in patients with PDA, thus being excluded from the list of frequent PDA-associated genetic defects.

Polymorphism in the Alpha Cardiac Muscle Actin 1 Gene Is Associated to Susceptibility to Chronic Inflammatory Cardiomyopathy

AimsChagas disease, caused by the protozoan Trypanosoma cruzi is endemic in Latin America, and may lead to a life-threatening inflammatory dilated, chronic Chagas cardiomyopathy (CCC). One third of T. cruzi-infected individuals progress to CCC while the others remain asymptomatic (ASY). A possible genetic component to disease progression was suggested by familial aggregation of cases and the association of markers of innate and adaptive immunity genes with CCC development. Since mutations in multiple sarcomeric genes, including alpha-cardiac actin (ACTC1) have been involved in hereditary dilated cardiomyopathy, we investigated the involvement of the ACTC1 gene in CCC pathogenesis. Methods and ResultsWe conducted a proteomic and genetic study on a Brazilian study population. The genetic study was done on a main cohort including 118 seropositive asymptomatic subjects and 315 cases and the replication was done on 36 asymptomatic and 102 CCC cases. ACTC1 protein and mRNA levels were lower in myocardial tissue from patients with end-stage CCC than those found in hearts from organ donors. Genotyping a case-control cohort of CCC and ASY subjects for all informative single nucleotide polymorphism (SNP) in the ACTC1 gene identified rs640249 SNP, located at the 5’ region, as associated to CCC. Associations are borderline after correction for multiple testing. Correlation and haplotype analysis led to the identification of a susceptibility haplotype. Functional assays have shown that the rs640249A/C polymorphism affects the binding of transcriptional factors in the promoter regions of the ACTC1 gene. Confirmation of the detected association on a larger independent replication cohort will be useful.ConclusionsGenetic variations at the ACTC1 gene may contribute to progression to chronic Chagas Cardiomyopathy among T. cruzi-infected patients, possibly by modulating transcription factor binding to ACTC1 promoter regions.