Dysfunctional regulatory T cell: May be an obstacle to immunotherapy in cardiovascular diseases.

Inflammatory responses are linked to cardiovascular diseases (CVDs) in various forms. Tregs, members of CD4+ T cells, play important roles in regulating immune system and suppressing inflammatory response, thus contributing to maintaining immune homeostasis. However, Tregs exert their powerful suppressive function relying on the stable phenotype and function. The stability of Tregs primarily depends on the FOXP3 (Forkhead box P3) expression and epigenetic regulation. Although Tregs are quite stable under physiological conditions, prolonged exposure to inflammatory cues, Tregs may lose suppressive function and require proinflammatory phenotype, namely plastic Tregs or ex-Tregs. There are extensive researches have established the beneficial role of Tregs in CVDs. Nevertheless, the potential risks of dysfunctional Tregs lack deep research. Anti-inflammatory and immunological modulation have been hotspots in the treatment of CVDs. Tregs are appealing because of their crucial role in resolving inflammation and promoting tissue repair. If alleviating inflammatory response through modulating Tregs could be a new therapeutic strategy for CVDs, the next step to consider is how to prevent the formation of dysfunctional Tregs or reverse detrimental Tregs to normal phenotype.

Reticulon 3 regulates sphingosine-1-phosphate synthesis in endothelial cells to control blood pressure.

The discovery of the endothelium as a major regulator of vascular tone triggered intense research among basic and clinical investigators to unravel the physiologic and pathophysiologic significance of this phenomenon. Sphingosine-l-phosphate (S1P), derived from the vascular endothelium, is a significant regulator of blood pressure. However, the mechanisms underlying the regulation of S1P biosynthetic pathways in arteries remain to be further clarified. Here, we reported that Reticulon 3 (RTN3) regulated endothelial sphingolipid biosynthesis and blood pressure. We employed public datasets, patients, and mouse models to explore the pathophysiological roles of RTN3 in blood pressure control. The underlying mechanisms were studied in human umbilical vein endothelial cells (HUVECs). We reported that increased RTN3 was found in patients and that RTN3-null mice presented hypotension. In HUVECs, RTN3 can regulate migration and tube formation via the S1P signaling pathway. Mechanistically, RTN3 can interact with CERS2 to promote the selective autophagy of CERS2 and further influence S1P signals to control blood pressure. We also identified an RTN3 variant (c.116C>T, p.T39M) in a family with hypertension. Our data provided the first evidence of the association between RTN3 level changes and blood pressure anomalies and preliminarily elucidated the importance of RTN3 in S1P metabolism and blood pressure regulation.

Correction to: Increased RTN3 phenocopies nonalcoholic fatty liver disease by inhibiting the AMPK-IDH2 pathway.

[This corrects the article DOI: 10.1002/mco2.226.].

Effect of ATG8 or SAC1 deficiency on the cell proliferation and lifespan of the long-lived PMT1 deficiency yeast cells.

Autophagy is pivotal in maintaining intracellular homeostasis, which involves various biological processes, including cellular senescence and lifespan modulation. Being an important member of the protein O-mannosyltransferase (PMT) family of enzymes, Pmt1p deficiency can significantly extend the replicative lifespan (RLS) of yeast cells through an endoplasmic reticulum (ER) unfolded protein response (UPR) pathway, which is participated in protein homeostasis. Nevertheless, the mechanisms that Pmt1p regulates the lifespan of yeast cells still need to be explored. In this study, we found that the long-lived PMT1 deficiency strain (pmt1Δ) elevated the expression levels of most autophagy-related genes, the expression levels of total GFP-Atg8 fusion protein and free GFP protein compared with wild-type yeast strain (BY4742). Moreover, the long-lived pmt1Δ strain showed the greater dot-signal accumulation from GFP-Atg8 fusion protein in the vacuole lumen through a confocal microscope. However, deficiency of SAC1 or ATG8, two essential components of the autophagy process, decreased the cell proliferation ability of the long-lived pmt1Δ yeast cells, and prevented the lifespan extension. In addition, our findings demonstrated that overexpression of ATG8 had no potential effect on the RLS of the pmt1Δ yeast cells, and the maintained incubation of minimal synthetic medium lacking nitrogen (SD-N medium as starvation-induced autophagy) inhibited the cell proliferation ability of the pmt1Δ yeast cells with the culture time, and blocked the lifespan extension, especially in the SD-N medium cultured for 15 days. Our results suggest that the long-lived pmt1Δ strain enhances the basal autophagy activity, while deficiency of SAC1 or ATG8 decreases the cell proliferation ability and shortens the RLS of the long-lived pmt1Δ yeast cells. Moreover, the maintained starvation-induced autophagy impairs extension of the long-lived pmt1Δ yeast cells, and even leads to the cell death.

Why help others? Insights from rodent to human early childhood research.

Helping behavior are actions aiming at assisting another individual in need or to relieve their distress. The occurrence of this behavior not only depends on automated physiological mechanisms, such as imitation or emotional contagion, that is, the individual's emotion and physiological state matching with others, but also needs motivation to sustain. From a comparative and developmental perspective, we discover that the motivation for helping behavior has a deep foundation both phylogenetically and ontogenetically. For example, empathic concern for others, relieving personal distress and the desire for social contact are universal motivations across rodents, non-human primates and human early childhoods. Therefore, a circle-layered model integrating evidences for motivation for helping behavior from rodent to human early childhood research is proposed: the inner circle contains the emotional-behavioral system and the outer circle contains the affective-cognitive system. The application of this model has significance for both behavioral neuroscience research and cultivating prosocial behavior in human society.

Increased RTN3 phenocopies nonalcoholic fatty liver disease by inhibiting the AMPK-IDH2 pathway.

Reticulon 3 (RTN3), an endoplasmic reticulum protein, is crucial in neurodegenerative and kidney diseases. However, the role of RTN3 in liver tissues has not been described. Here, we employed public datasets, patients, and several animal models to explore the role of RTN3 in nonalcoholic fatty liver disease (NAFLD). The underlying mechanisms were studied in primary hepatocytes and L02 cells in vitro. We found an increased expression of RTN3 in NAFLD patients, high-fat diet mice, and oxidized low-density lipoprotein-treated L02 cells. The RTN3 transgenic mice exhibited the phenotypes of fatty liver and lipid accumulation. Single-cell RNA sequencing analysis indicated that increased RTN3 might induce mitochondrial dysfunction. We further showed this in primary hepatocytes, the L02 cell line, and the Caenorhabditis elegans strain. Mechanistically, RTN3 regulated these events through its interactions with glucose-regulated protein 78 (GRP78), which further inhibited the adenosine 5 monophosphate-activated protein kinase (AMPK)-isocitrate dehydrogenase 2 (IDH2) pathway. In the end, knockout of RTN3 relieved fatty liver and mitochondrial dysfunction. Our study indicated that RTN3 was important in NAFLD and lipid catabolism and that an increase in RTN3 in the liver might be a risk factor for nonalcoholic steatohepatitis and NAFLD.

Conciliatory Anti-Allergic Decoction Attenuates Pyroptosis in RSV-Infected Asthmatic Mice and Lipopolysaccharide (LPS)-Induced 16HBE Cells by Inhibiting TLR3/NLRP3/NF-κB/IRF3 Signaling Pathway.

Respiratory syncytial virus (RSV) infection can deteriorate asthma by inducing persistent airway inflammation. Increasing evidence elucidated that pyroptosis plays a pivotal role in asthma. Conciliatory anti-allergic decoction (CAD) exhibits an anti-inflammatory effect in ovalbumin (OVA)-induced asthma; however, the effects and mechanisms of CAD in RSV-infected asthmatic mice have not yet been elucidated. The RSV-infected asthmatic mice model and lipopolysaccharide (LPS)-induced 16HBE cell pyroptosis model were established, respectively. Pulmonary function, ELISA, and histopathologic analysis were performed to assess the airway inflammation and remodeling in mice with CAD treatment. Furthermore, ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) was conducted to identify the chemical compounds of high-dose CAD (30 g/kg). Cell viability and apoptosis of 16HBE cells were assessed by CCK-8 and flow cytometry assays, respectively. Finally, the expression levels of apoptosis-, pyroptosis-, and TLR3/NLRP3/NF-κB/IRF3 signaling-related genes were measured with qRT-PCR or western blotting, respectively. Pulmonary function tests showed that CAD significantly ameliorated respiratory dysfunction, airway hyperresponsiveness, inflammation cell recruitment in BALF, pulmonary inflammation, collagen deposition, and cell death in lung tissues. CAD significantly decreased the content of TNF-α, IL-13, IL-4, IL-1ß and IL-5 in the bronchoalveolar lavage fluid (BALF), IL-17, IL-6, and OVA-specific IgE in serum and increased serum IFN-γ in asthma mice. The results of UPLC-Q-TOF/MS showed that high-dose CAD had 88 kinds of chemical components. In vitro, CAD-contained serum significantly suppressed LPS-induced 16HBE cell apoptosis. Additionally, CAD and CAD-contained serum attenuated the up-regulated expressions of Bax, Cleaved caspase-3, NLRP3, ASC, Cleaved caspase-1, GSDMD-N, IL-18, IL-1ß, TLR3, p-P65, p-IκBα, and IRF3 but increased Bcl-1 and GSDMD levels in the asthma mice and LPS-induced 16HBE cells, respectively. These results illustrated that CAD may have a potential role in improving airway inflammation and pyroptosis through inhibition of the TLR3/NLRP3/NF-κB/IRF3 signaling pathway.

N-acetyl cysteine ameliorates aortic fibrosis by promoting M2 macrophage polarization in aging mice.

Background: Vascular fibrosis is a universal phenomenon associated with aging, and oxidative stress plays an important role in the genesis of vascular damage in line with the aging process. However, whether antioxidants can ameliorate vascular fibrosis remains unclear.Objectives: The present study was to determine antioxidant N-acetylcysteine (NAC) could ameliorates aortic fibrosis in aging wild-type C57BL/6 mice.Methods: The aortas were harvested from both 12-week and 60-week wild-type mice. The 60-week mice were treated with and without the NAC for 12 weeks starting at the age of 48 weeks. Hematoxylin and eosin (H&E) staining and Masson's trichrome staining of aortic samples were performed, and the levels of reactive oxygen species (ROS), RNA expression of GAPDH, TNF-α, MCP-1, IL-6, IL-10, IL-4, SIRT-1, SIRT-3, FOXO-1, and macrophage polarization were determined.Results: There is a positive relationship between collagen deposition and the M1/M2 macrophage ratio in the aortic wall of aged wild-type C57BL/6 mice. The higher collagen area percentage in the aortas of 60-week-old mice than in 12-week-old mice was reversed by NAC. NAC could not impact the total number of macrophages, but partly promoted M2 macrophage polarization. By performing qRT-PCR using aortic samples from these mice, we identified that SIRT-1, SIRT-3, FOXO-1 could be somehow responsible for aging-related fibrosis.Conclusions: NAC ameliorates aortic fibrosis in aging wild type mice partly by promoting M2 macrophage polarization.

Whole-Exome Sequencing Identifies a Novel TRPM4 Mutation in a Chinese Family with Atrioventricular Block.

Atrioventricular block (AVB) is a leading cause of sudden cardiac death, and most of AVB cases are presented as autosomal dominant. The electrocardiogram of AVB patients presents an abnormal progressive cardiac conduction disorder between atria and ventricles. Transient receptor potential melastatin 4 (TRPM4) is a nonselective Ca2+-activated cation channel gene defined as a novel disease-causing gene of AVB. So far, 47 mutations of TRPM4 have been recorded in Human Gene Mutation Database. The aim of this study was to explore the relationship between TRPM4 mutation and pathogenesis of AVB. We investigated a Chinese family with AVB by whole-exome sequencing. An arrhythmia-related gene filtering strategy was used to analyze the disease-causing mutations. Three different bioinformatics programs were used to predict the effects of the mutation result. A novel mutation of TRPM4 was identified (c.2455C>T/p.R819C) and cosegregated in the affected family members. The three bioinformatics programs predicted that the novel mutation may lead to damage. Our study will contribute to expand the spectrum of TRPM4 mutations and supply accurate genetic testing information for further research and the clinical therapy of AVB.

A Novel Nonsense Mutation of ABCA8 in a Han-Chinese Family With ASCVD Leads to the Reduction of HDL-c Levels.

Arteriosclerotic cardiovascular disease (ASCVD) is one of the major causes of death worldwide and most commonly develops as a result of atherosclerosis (AS). As we all know, dyslipidemia is a leading pathogenic risk factor for ASCVD, which leads to cardiac ischemic injury and myocardial infarction. Dyslipidemias include hypercholesterolemia, hypertriglyceridemia, increased low-density lipoprotein cholesterol (LDL-c) and decreased high density lipoproteins cholesterol (HDL-c). Mutations of dyslipidemia related genes have been proved to be the crucial contributor to the development of AS and ASCVD. In this study, a Han-Chinese family with ASCVD was enrolled and the lipid testing discovered an obvious reduced levels of HDL-c in the affected members. We then performed whole exome sequencing to detect the candidate genes of the family. After data filtering, a novel heterozygous nonsense mutation (NM_007168: c.3460C>T; p.R1154X) of ABCA8 was detected and validated to be co-separated in the family members by Sanger sequencing. Previous studies have proved that deleterious heterozygous ABCA8 variants may disrupt cholesterol efflux and reduce HDL-c levels in humans and mice. This study may be the second report related to ABCA8 mutations in patients with reduced levels of HDL-c. Our study not only contributed to the genetic counseling and prenatal genetic diagnosis of patients with ASCVD caused by reduced HDL-c levels, but also provided a new sight among ABCA8, cholesterol efflux and HDL-c levels.

Efficacy and safety of coenzyme A versus fenofibrate in patients with hyperlipidemia: a multicenter, double-blind, double-mimic, randomized clinical trial.

Background: We investigated the lipid-lowering efficacy and safety of coenzyme A (CoA) versus fenofibrate in Chinese patients with moderate dyslipidemia.Methods: A total of 417 subjects (aged 18-75 years) diagnosed with moderate dyslipidemia (triglyceride 2.3-6.5 mmol/L) from 13 large cardiovascular centers in China were recruited and randomly divided into a fenofibrate group (n = 207), which received 200 mg of fenofibrate orally once daily, and a CoA group (n = 210), which received 400 mg of CoA orally once a day. Blood lipoproteins, liver and renal function, creatine kinase, and blood glucose were measured at baseline, and after 4 and 8 weeks of treatment.Results: The baseline triglyceride (TG) level in the fenofibrate group and the CoA group was 3.39 ± 0.99 mmol/L and 3.60 ± 1.11 mmol/L, respectively. After treatment for 4 and 8 weeks with fenofibrate, TG was reduced by 31.62% and 33.13%. In the CoA group, TG was reduced by 17.29% and 23.80%. Compared with baseline, total cholesterol (TC) was significantly decreased in both groups after either 4 or 8 weeks of treatment (p < .05). CoA increased high-density lipoprotein cholesterol (HDL-C) after 4 weeks of treatment, whereas it had no significant effect on HDL-C after 8 weeks of treatment. Low-density lipoprotein cholesterol (LDL-C) was not modified in either group. The incidence of side effects was significantly lower in the CoA group compared with the fenofibrate group (p < .05).Conclusions: Compared with fenofibrate, CoA has less effect on reducing plasma TG levels in subjects with moderate dyslipidemia. However, it has fewer adverse effects.

GAS1 Deficient Enhances UPR Activity in Saccharomyces cerevisiae.

Beta-1,3-glucanosyltransferase (Gas1p) plays important roles in cell wall biosynthesis and morphogenesis and has been implicated in DNA damage responses and cell cycle regulation in fungi. Yeast Gas1p has also been reported to participate in endoplasmic reticulum (ER) stress responses. However, the precise roles and molecular mechanisms through which Gas1p affects these responses have yet to be elucidated. In this study, we constructed GAS1-deficient (gas1Δ) and GAS1-overexpressing (GAS1 OE) yeast strains and observed that the gas1Δ strain exhibited a decreased proliferation ability and a shorter replicative lifespan (RLS), as well as enhanced activity of the unfolded protein response (UPR) in the absence of stress. However, under the high-tunicamycin-concentration (an ER stress-inducing agent; 1.0 µg/mL) stress, the gas1Δ yeast cells exhibited an increased proliferation ability compared with the wild-type yeast strain. In addition, our findings demonstrated that IRE1 and HAC1 (two upstream modulators of the UPR) are required for the survival of gas1Δ yeast cells under the tunicamycin stress. On the other hand, we provided evidence that the GAS1 overexpression caused an obvious sensitivity to the low-tunicamycin-concentration (0.25 µg/mL). Collectively, our results indicate that Gas1p plays an important role in the ageing and ER stress responses in yeast.

Transcatheter Closure of Complex Post-Myocardial Infarction Left Ventricular Pseudoaneurysm and Unique Post-Traumatic Right Ventricular Pseudoaneurysm.

Ventricular pseudoaneurysm (PSA) is a rare, yet life-threatening complication of myocardial infarction, cardiac surgery, and transcatheter valve replacement. Although conventional surgery is the preferred treatment strategy, transcatheter closure has emerged as an effective alternative in selected candidates. In this report, we describe successful transcatheter closure of two unique cases of ventricular pseudoaneurysm (PSA): first, a complex post-myocardial infarction left ventricular PSA (LVPSA) with multi-communications, and second, a case of post-traumatic right ventricular PSA (RVPSA) following blunt chest injury caused by domestic violence.

Whole-Exome Sequencing Identifies a Novel Mutation (p.L320R) of Alpha-Actinin 2 in a Chinese Family with Dilated Cardiomyopathy and Ventricular Tachycardia.

Dilated cardiomyopathy (DCM) is a severe cardiovascular disease which can lead to heart failure and sudden cardiac death (SCD). The typical feature of DCM is left ventricular enlargement or dilatation. In some conditions, DCM and arrhythmia can occur concurrently, apparently promoting the prevalence of SCD. According to previous studies, mutations in more than 100 genes have been detected in DCM and/or arrhythmia patients. Here, we report a Chinese family with typical DCM, ventricular tachycardia, syncope, and SCD. Using whole-exome sequencing, a novel, likely pathogenic mutation (c.959T>G/p.L320R) of actinin alpha 2 (ACTN2) was identified in all affected family members. This novel mutation was also predicted to be disease-causing by MutationTaster, SIFT, and Polyphen-2. Our study not only expands the spectrum of ACTN2 mutations and contributes to the genetic diagnosis and counseling of the family, but also provides a new case with overlap phenotype that may be caused by the ACTN2 variant.

A de novo mutation of SMYD1 (p.F272L) is responsible for hypertrophic cardiomyopathy in a Chinese patient.

Background Hypertrophic cardiomyopathy (HCM) is a serious disorder and one of the leading causes of mortality worldwide. HCM is characterized as left ventricular hypertrophy in the absence of any other loading conditions. In previous studies, mutations in at least 50 genes have been identified in HCM patients. Methods In this research, the genetic lesion of an HCM patient was identified by whole exome sequencing. Real-time polymerase chain reaction (PCR), immunofluorescence and Western blot were used to analyze the effects of the identified mutation. Results According to whole exome sequencing, we identified a de novo mutation (c.814T>C/p.F272L) of SET and MYND domain containing histone methyltransferase 1 (SMYD1) in a Chinese patient with HCM exhibiting syncope. We then generated HIS-SMYD1-pcDNA3.1+ (WT and c.814T>C/p.F272L) plasmids for transfection into AC16 cells to functionalize the mutation. The immunofluorescence experiments indicated that this mutation may block the SMYD1 protein from entering the nucleus. Both Western blot and real-time PCR revealed that, compared with cells transfected with WT plasmids, the expression of HCM-associated genes such as ß-myosin heavy chains, SMYD1 chaperones (HSP90) and downstream targets including TGF-ß were all disrupted in cells transfected with the mutant plasmid. Previous studies have demonstrated that SMYD1 plays a crucial role in sarcomere organization and heart development. Conclusions This novel mutation (c.814T>C/p.F272L) may be the first identified disease-causing mutation of SMYD1 in HCM patients worldwide. Our research expands the spectrum of HCM-causing genes and contributes to genetic counseling for HCM patients.

Exome sequencing identifies a novel nonsense mutation of Ring Finger Protein 207 in a Chinese family with Long QT syndrome and syncope.

Long QT syndrome (LQTS) is a rare inherited arrhythmia disease characterized by a prolonged QT interval on 12-lead electrocardiograms. It is the crucial factor to induce syncope, ventricular fibrillation, and even sudden cardiac death. Previous studies have proved that mutations of ion channels-related genes play an important role in LQTS patients. In this study, we enrolled a Chinese family with LQTS and syncope. With the help of whole-exome sequencing, we identified a novel nonsense mutation (c.439C>T/p.Q147X) of Ring Finger Protein 207 (RNF207) in this family. The novel mutation, resulting in a premature stop codon in exon 4 of the RNF207 gene, co-segregated with the affected individuals. Bioinformatics analysis and real-time PCR further proved that the newly identified mutation might induce nonsense-mediated mRNA decay. In mutation carriers, the level of RNF207 mRNA expression was much lower than controls, which may affect potassium channel KCNH2 and lead to LQTS and syncope. In this research, we reported a rare novel mutation of RNF207 in LQTS and syncope patients which further supports the significant role of RNF207 in potassium channel activation and expanded the spectrum of RNF207 mutations. These data may contribute to the genetic diagnosis and counseling of families with LQTS and syncope.

Whole-exome sequencing reveals doubly novel heterozygous Myosin Binding Protein C and Titin mutations in a Chinese patient with severe dilated cardiomyopathy.

BACKGROUND: Dilated Cardiomyopathy is a serious heart disorder that may induce sudden cardiac death and heart failure. Significant progress has been made in understanding the molecular basis of dilated cardiomyopathy. In previous studies, mutations in more than fifty genes have been identified in dilated cardiomyopathy patients. The purpose of this study was to detect the genetic lesion in a family from the central south of China affected by severe dilated cardiomyopathy. METHODS: Whole-exome sequencing combined with cardiomyopathy-related genes list were used to analyse the mutations of the proband. Co-segregation analysis was performed by Sanger sequencing.Results and conclusionsTwo novel heterozygous mutations - Myosin Binding Protein C: p.L1014RfsX6 and Titin: p.R9793X - were identified in the proband. The deletion mutation c.3041delT/p.L1014RfsX6 caused a premature stop codon at position 1020 in exon 28 of the Myosin Binding Protein C. The nonsense mutation, c.29377 C>T/ p. R9793X, of Titin was located in the highly evolutionarily conserved domain, resulting in truncation of the Titin protein as well. Co-segregation analysis further revealed that the Myosin Binding Protein C mutation came from his mother and the Titin mutation came from his father. Both mutations are reported in dilated cardiomyopathy patients for the first time. Our study not only provides a unique example of the genes and molecular mechanisms involved in dilated cardiomyopathy but also expands the spectrum of Myosin Binding Protein C and Titin mutations and contributes to the genetic diagnosis and counselling of dilated cardiomyopathy patients.

Increased Reticulon 3 (RTN3) Leads to Obesity and Hypertriglyceridemia by Interacting With Heat Shock Protein Family A (Hsp70) Member 5 (HSPA5).

BACKGROUND: Reticulon 3 (RTN3) is an endoplasmic reticulum protein that has previously been shown to play a role in neurodegenerative diseases, but little is known about its role in lipid metabolism. METHODS: Obese patients (n=149), hypertriglyceridemic patients (n=343), and healthy control subjects (n=84) were enrolled to assess their levels of RTN3. To explore the pathophysiological roles of RTN3 in the control of lipid metabolism, we used transgenic mice overexpressing the wild-type human RTN3 gene, the RTN3-null transgenic mouse model, and multiple Caenorhabditis legans strains for molecular characterization. The underlying mechanisms were studied with 3T3L1 cell cultures in vitro. RESULTS: We report that overexpressed RTN3 in mice induces obesity and higher accumulation of triglycerides. Increased RTN3 expression is also found in patients with obesity and hypertriglyceridemia. We reveal that RTN3 plays critical roles in regulating the biosynthesis and storage of triglycerides and in controlling lipid droplet expansion. Mechanistically, RTN3 regulates these events through its interactions with heat shock protein family A (Hsp70) member 5, and this enhanced interaction increases sterol regulatory element-binding protein 1c and AMP-activated kinase activity. CONCLUSIONS: This study provides evidence for a role of RTN3 in inducing obesity and triglyceride accumulation and suggests that inhibiting the expression of RTN3 in fat tissue may be a novel therapeutic approach to treat obesity and hypertriglyceridemia.

Whole-exome sequencing identifies a Novel SCN5A mutation (C335R) in a Chinese family with arrhythmia.

BACKGROUND: SCN5A encodes sodium-channel α-subunit Nav1.5. The mutations of SCN5A can lead to hereditary cardiac arrhythmias such as the long-QT syndrome type 3 and Brugada syndrome. Here we sought to identify novel mutations in a family with arrhythmia. METHODS: Genomic DNA was isolated from blood of the proband, who was diagnosed with atrial flutter. Illumina Hiseq 2000 whole-exome sequencing was performed and an arrhythmia-related gene-filtering strategy was used to analyse the pathogenic genes. Sanger sequencing was applied to verify the mutation co-segregated in the family.Results and conclusionsA novel missense mutation in SCN5A (C335R) was identified, and this mutation co-segregated within the affected family members. This missense mutation was predicted to result in amplitude reduction in peak Na+ current, further leading to channel protein dysfunction. Our study expands the spectrum of SCN5A mutations and contributes to genetic counselling of families with arrhythmia.

Whole exome sequencing identifies a novel mutation (c.333 + 2T > C) of TNNI3K in a Chinese family with dilated cardiomyopathy and cardiac conduction disease.

Dilated Cardiomyopathy (DCM) and cardiac conduction disease (CCD) are two kinds if diseases that can induce heart failure, syncope and even sudden cardiac death (SCD). DCM patients can experience CCD at the same time. In recent research, some disease-causing genes and variants have been identified in patients with DCM and CCD, such as Alpha-Actinin-2 and TNNI3 Interacting Kinase (TNNI3K). In this study, we employed whole-exome sequencing (WES) to explore the potential causative genes in a Chinese family with DCM and CCD. A novel splice site mutation (c.333 + 2 T > C) of TNNI3K was identified and co-segregated with the affected family members. This novel mutation was also absent in 200 healthy local controls and predicted to be disease-causing by Mutationtaster. The splice site mutation (c.333 + 2 T > C) may result in a premature stop codon in exon 4 of the TNNI3K gene and can induce nonsense-mediated mRNA decay. Real-time qPCR also confirmed that the level of TNNI3K mRNA expression was decreased significantly compared with the controls, which may lead to myocardial structural disorder and arrhythmia. In this study we reported the third novel mutation of TNNI3K in DCM and CCD patients which further supported the important role of TNNI3K in heart development and expanded the spectrum of TNNI3K mutations. The results may contribute to the genetic diagnosis and counseling of families with DCM and CCD.