Haoming Song

HAND1 loss-of-function mutation associated with familial dilated cardiomyopathy

Abstract Background: The basic helix-loop-helix transcription factor HAND1 is essential for cardiac development and structural remodeling, and mutations in HAND1 have been causally linked to various congenital heart diseases. However, whether genetically compromised HAND1 predisposes to dilated cardiomyopathy (DCM) in humans remains unknown. Methods: The whole coding region and splicing junctions of the HAND1 gene were sequenced in 140 unrelated patients with idiopathic DCM. The available family members of the index patient carrying an identified mutation and 260 unrelated ethnically matched healthy individuals used as controls were genotyped for HAND1. The functional effect of the mutant HAND1 was characterized in contrast to its wild-type counterpart by using a dual-luciferase reporter assay system. Results: A novel heterozygous HAND1 mutation, p.R105X, was identified in a family with DCM transmitted as an autosomal dominant trait, which co-segregated with DCM in the family with complete penetrance. The nonsense mutation was absent in 520 control chromosomes. Functional analyses unveiled that the mutant HAND1 had no transcriptional activity. Furthermore, the mutation abolished the synergistic activation between HAND1 and GATA4, another crucial cardiac transcription factors that has been associated with various congenital cardiovascular malformations and DCM. Conclusions: This study firstly reports the association of HAND1 loss-of-function mutation with increased susceptibility to DCM in humans, which provides novel insight into the molecular mechanisms underpinning DCM.

Mutational spectrum of the NKX2-5 gene in patients with lone atrial fibrillation.

Atrial fibrillation (AF) is the most common form of sustained cardiac arrhythmia in humans and is responsible for substantial morbidity and mortality worldwide. Emerging evidence indicates that abnormal cardiovascular development is involved in the pathogenesis of AF. In this study, the coding exons and splice sites of the NKX2-5 gene, which encodes a homeodomain-containing transcription factor essential for cardiovascular genesis, were sequenced in 146 unrelated patients with lone AF as well as the available relatives of the mutation carriers. A total of 700 unrelated ethnically matched healthy individuals used as controls were genotyped. The disease-causing potential of the identified NKX2-5 variations was predicted by MutationTaster and PolyPhen-2. The functional characteristics of the mutant NKX2-5 proteins were analyzed using a dual-luciferase reporter assay system. As a result, two heterozygous NKX2-5 mutations, including a previously reported p.E21Q and a novel p.T180A mutation, were identified in two families with AF transmitted in an autosomal dominant pattern. The mutations co-segregated with AF in the families with complete penetrance. The detected substitutions, which altered the amino acids highly conserved evolutionarily across species, were absent in 700 control individuals and were both predicted to be causative. Functional analyses demonstrated that the NKX2-5 mutants were associated with significantly decreased transcriptional activity compared with their wild-type counterpart. The findings expand the spectrum of NKX2-5 mutations linked to AF and provide additional evidence that dysfunctional NKX2-5 may confer vulnerability to AF, suggesting the potential benefit for the early prophylaxis and personalized treatment of AF.

Symptomatic Venous Thromboembolism Is a Disease Related to Infection and Immune Dysfunction

The characteristics of human genomics and cellular immune function between clinically symptomatic venous thromboembolism (VTE) and controls were systematically compared to explore the immunologic pathogenesis of VTE. Microarray assay showed the mRNA expressions of genes related to non-specific cellarer immune and cytokines were significantly down-regulated. Abnormal expressions of CD3+, CD4+, CD8+, NK marker CD16+56+, CD19 and aberrant CD4+/CD8+ ratio were detected in 54 among 56 patients. In PE patients, microarray assay revealed the imbalance in the expressions of genes related to the immune system. The expressions of genes related to non-specific immune cells and cytokines were markedly up-regulated and those associated with cellular immune were dramatically down-regulated. In VTE patients, cytological examination indicated the functions of NK cells were significantly compromised, and the antigen recognition and killing function of T cells markedly decreased. The consistence between genomic and cytological examination suggests the symptomatic VTE is closely associated with the infection and immune dysfunction.

VE/VCO2 slope and its prognostic value in patients with chronic heart failure.

The minute ventilation/carbon dioxide production (VE/VCO2) slope has been widely demonstrated to have strong prognostic value in patients with chronic heart failure (CHF), and the risk of mortality is believed to increase when the VE/VCO2 slope is >32.8; however, there is little evidence concerning the prognostic value of the VE/VCO2 slope in Chinese patients. In the present study, the prognostic value of the VE/VCO2 slope was investigated in patients with CHF. A total of 258 subjects underwent symptom-limited cardiopulmonary exercise testing (CPET) and were divided into CHF (113 males and 16 females; LVEF <0.49) and control (106 males and 23 females) groups. The cardiac-related events over a median 33.7-month follow-up period subsequent to the CPET were evaluated using receiver operating characteristic curve analysis. The VE/VCO2 slope was significantly different between the CHF and control groups (P<0.001). The area under the curve (AUC) for the VE/VCO2 slope in predicting cardiac-related mortalities in the patients with CHF was 0.670 (P<0.05), and the sensitivity and specificity of the VE/VCO2 slope were 0.667 and 0.620, respectively. The optimal threshold of the VE/VCO2 slope for predicting cardiac-related mortalities in patients with CHF was ≥39.3. The AUC for the VE/VCO2 slope in predicting cardiac-related hospitalizations in patients with CHF was 0.682 (P<0.05), and the sensitivity and specificity of the VE/VCO2 slope were 0.631 and 0.778, respectively. The optimal threshold of the VE/VCO2 slope for predicting cardiac-related hospitalizations in patients with CHF was ≥32.9. In conclusion, ventilatory efficiency decreases in patients with CHF. The VE/VCO2 slope is a strong predictor of cardiac-related mortalities in the patients with CHF analyzed.

Characteristics of the complement system gene expression deficiency in patients with symptomatic pulmonary embolism

Abstract Introduction Pulmonary embolism (PE) is a disease with a high mortality and morbidity rate, and the pathogenesis of PE remains still unclear. We aimed to investigate the gene expression differences of the complement system in peripheral blood mononuclear cells (PBMCs) from patients with symptomatic PE and controls. Methods Twenty cases of PE patients and twenty sex and age matched controls were recruited into the study. Human cDNA microarray analysis was used to detect the gene expression difference of the complement system between the two groups. Results 1). Expression of twenty-one genes encoding complement components was detected. In PE patients, expression of the genes encoding C1qα, C1qβ, C4b, C5 and Factor P was significantly greater (P<0.05) than controls, while C6, C7, C9, mannose-binding lectin (MBL) and mannan-binding lectin serine peptidase 1 (MASP1) mRNAs were lower (P<0.05) than controls. 2). Expression of seven genes encoding complement receptors was examined. In PE patients, CR1, integrin αM, integrin αX and C5aR mRNAs were significantly up-regulated (P<0.01) compared with controls. 3). Seven genes encoding complement regulators were examined. The mRNA expression of CD59 and CD55 was significantly up-regulated (P<0.05), whereas Factor I mRNA was significantly down-regulated (P<0.05) in PE patients than controls. Conclusions In PE patients, the mRNA expressions of complement components, receptors and regulators were unbalanced, suggesting dysfunction and/or deficiency of the complement system, which leads to decreased function of MAC-induced cell lysis in PE patients finally.

Analysis on the pathogenesis of symptomatic pulmonary embolism with human genomics.

BACKGROUND: In the present study, the whole human genome oligo microarray was employed to investigate the gene expression profile in symptomatic pulmonary embolism (PE). METHODS: Twenty patients with PE and 20 age and gender matched patients without PE as controls were enrolled into the present study in the same period. The diagnosis of PE was based on the clinical manifestations and findings on imaging examinations. Acute arterial and/or venous thrombosis was excluded in controls. The whole human genome oligo microarray was employed for detection. Statistical analysis was performed with t test following analysis of very small samples of repeated measurements and Gene Ontology (GO) analysis. RESULTS: Genomic data showed no damage to vascular endothelial cells in PE patients. Genomic data only found increased mRNA expression of a small amount of coagulation factors in PE patients. In the PE group, anticoagulant proteins, Fibrinolytic system and proteins related to platelet functions only played partial roles in the pathogenesis of PE. In addition, the mRNA expressions of a fraction of adhesion molecules were markedly up-regulated. Gene Ontology analysis showed the genes with down-regulated expressions mainly explain the compromised T cell immunity. Symptomatic VTE patients have compromised T cell immunity. CONCLUSION: The damage to vascular endothelial cells is not necessary in the pathogenesis of VTE, and only a fraction of factors involved in the shared coagulation cascade are activated. Genomic results may provide a new clue for clinical diagnosis, treatment and prevention of VTE.

Immune Cell Repertoire and Their Mediators in Patients with Acute Myocardial Infarction or Stable Angina Pectoris

Background: To evaluate the natural innate and adaptive immunity through gene expression and cytology levels in peripheral blood mononuclear cells in patients with acute myocardial infarction (AMI), stable angina pectoris (SAP) and controls. Methods: 210 patients with AMI, 210 with SAP, and 250 clinical controls were recruited. Whole human genome microarray analysis was performed in 20 randomly chosen subjects per group were examined to detect the expressions of complement markers, natural killer cells, T cells and B cells. The quantity of these cells and related cytokines as well as immunoglobulin levels were measured in all subjects. Results: In AMI group, the mRNA expressions of late complement component, markers of natural killer cells, CD3+, CD8+ T cells and B cells were down-regulated, while those of early complement component and CD4+T cells were up-regulated (p<0.05). In both AMI and SAP patients, the quantity of natural killer cells, CD3+, CD8+ T cells, B cells, IgM and IgG were significantly lower than those of the controls. CD4+ T cells, CH50, C3, C4, IL-2, IL-4, IL-6 and IFN-γ were significantly higher (p<0.05). Conclusions: In AMI patients, both of gene expressions related to complement, natural killer cells, CD3+, CD8+ T cells, B cells and the quantity of these immune cells decreased while cell number reduced in SAP patients. Immune function in both AMI and SAP patients decreased especially in AMI patients with declined gene and protein levels. To improve the immune system is a potential target for medical interventions and prevention in AMI.

The Prognostic Value of Peak Cardiac Power Output in Chinese Patients with Chronic Heart Failure.

Background Cardiopulmonary exercise testing has been widely used to risk stratify patients with chronic heart failure (CHF). Peak oxygen consumption (peakVO2) was regarded as a powerful predictor of survival, as it is a surrogate for peak cardiac output (CO), which by most is considered the “true” measure of heart failure. Therefore, it is reasonable to hypothesize that CO is an even stronger predictor than peak VO2. The present study is aimed to investigate the prognostic value of peak cardiac power output (peak CPO) in comparison with peakVO2 in Chinese patients with CHF. Methods Participants provided written informed consent to participate in this study. Totally 129 patients with CHF underwent symptom-limited cardiopulmonary exercise testing (CPET), with mean age 59.1±11.4 years, 87.6% male, 57.4% ischemic etiology, body mass index (BMI) 24.7±3.7 kg/m2 and LVEF 38±9%. CO was measured using an inert gas rebreathing method. The primary endpoints are cardiac deaths. Results Over median 33.7-month follow-up, 19 cardiac deaths were reported. Among peak VO2,VE/VCO2 slope and Peak CPO, their area under ROC were 0.64, 0.67, 0.68, respectively (Ρ<0.05).The optimal thresholds for predicting cardiac deaths were peak VO2≤13.4 ml.kg-1.min-1, and VE/VCO2 slope≥39.3 and peak CPO≤ 1.1 respectively by ROC analysis. Finally, in patients with a peak VO2≤13.4 ml.kg-1.min-1 those with peak CPO>1.1W had better survival than those with peak CPO ≤ 1.1W. However, by multivariate analysis adjusted for age, sex, BMI, resting heart rate, LVMI, LVEF, Peak CPO was not an independent predictor of cardiac deaths (P> 0.05). Conclusions Peak CPO was not a predictor of cardiac death in Chinese CHF patients.

Immune function of peripheral T cells in patients with venous thromboembolism or coronary artery atherosclerosis.

INTRODUCTION AND OBJECTIVES Recent studies have shown that the major risk factors for arterial thrombotic diseases are closely associated with venous thromboembolism (VTE). This study aimed to investigate the expression of CD3, CD4 and CD8 in T lymphocytes, the CD4/CD8 ratio and high-sensitivity C-reactive protein (hs-CRP) levels in patients with VTE, coronary artery atherosclerosis (CAA) and healthy subjects. METHODS A total of 82 healthy subjects, 51 VTE patients and 114 CAA patients were recruited, and the expression of CD3, CD4 and CD8 in T lymphocytes and the CD4/CD8 ratio were determined. Serum hs-CRP was also measured. RESULTS Compared to healthy subjects, VTE patients had significantly reduced CD3 expression (p=0.019), comparable CD4 expression (p=0.868), significantly reduced CD8 expression (p<0.001) and increased CD4/CD8 ratio (p=0.044). However, VTE patients had comparable expression of CD3, CD4 and CD8 and CD4/CD8 ratio to CAA patients. In addition, among patients with VTE or CAA, the proportion of patients with reduced CD3+ and CD8+ T lymphocytes or increased CD4/CD8 ratio was significantly higher than in healthy subjects. In addition, hs-CRP in both VTE and CAA groups was significantly higher than in healthy subjects. CONCLUSIONS The antigen recognition and signal transduction activation of T cells is significantly reduced in patients with VTE or CAA, and the killing effect of T cells on pathogens, including viruses, is also significantly compromised. In addition, inflammatory and immune mechanisms are involved in the occurrence and development of venous and arterial thrombosis.

GENOMIC CHARACTERISTICS OF ADHESION MOLECULES IN PATIENTS WITH SYMPTOMATIC PULMONARY EMBOLISM

Objectives To find out the differences of cell adhesion molecule-related mRNAs expression between symptomatic pulmonary embolism (PE) and control group, and to investigate the interactions among activated leukocytes, platelets and endothelial cells. Methods Whole human gene chip was applied to detect cell adhesion molecule-related mRNAs expression in symptomatic PE and control group, and then statistical analysis was performed. Results In patients with PE, the expression of most mRNAs related to integrins which located in leukocytes and platelets was significantly up-regulated; the expression of mRNAs related to L-selectin and P-selectin glycoprotein ligand was significantly up-regulated, while the expression of mRNA related to E-selectin was significantly down-regulated; the expression of mRNAs related to classic cadherins and protocadherins tended to down-regulate as a whole, and the expression of mRNA related to vascular endothelial cell cadherin was significantly down-regulated; the expression of mRNAs related to the immunoglobulin superfamily had no obvious difference between the two groups. Conclusions The results demonstrated that, in symptomatic PE patients, the adhesion of leukocytes and platelets were enhanced; the activation of endothelial cells was obviously weakened; the adherens junctions among endothelial cells were weakened, with the endothelium becoming more permeable.