Longxian Cheng

Associations Between Single Nucleotide Polymorphisms on Chromosome 9p21 and Risk of Coronary Heart Disease in Chinese Han Population

Objectives—We aimed to determine whether the single nucleotide polymorphisms (SNPs) on chromosome 9p21 were associated with coronary heart disease (CHD) in a Chinese Han population. Methods and Results—We determined the genotypes of rs2383206 and rs2383207 on chromosome 9p21 in 1360 CHD patients and 1360 age- and sex-frequency–matched controls from an unrelated Chinese Han population. GG genotypes in rs2383207 occurred more frequently in CHD patients compared to controls, and the odds ratio (OR) was 1.52 (95% CI 1.13 to 2.04), after adjusting for conventional risk factors. In stratified analysis, the risk associated with the GG genotype of the two SNPs was stronger in subjects who were males, less than 60 years old, overweight, and smokers. The SNP rs2383207 had significant interactions with gender and smoking (P=0.018 and 0.037, respectively). The risk allele G of rs2383207 plus family history of CHD had a cumulative association with CHD (P for trend, 1.0×10−6); the OR for CHD was 4.59 (95% CI 2.52 to 8.37) for those with all the risk factors as compared with subjects without any of the factors. Conclusions—The SNP rs2383207 on chromosome 9p21 is significantly associated with CHD in Chinese. This SNP combined with family history has a cumulative association with CHD.

Plasma levels of Hsp70 and anti-Hsp70 antibody predict risk of acute coronary syndrome

Although immune reactions against heat shock proteins have been implicated in the pathogenesis of atherosclerosis, conflicting associations between Hsp70, anti-Hsp70 antibody and coronary heart disease (CHD) have been reported. This study assessed whether there is a significant association between extracellular human Hsp70, anti-Hsp70 antibody and acute coronary syndrome (ACS) and stable angina (SA), and examined dynamic changes in Hsp70 and anti-Hsp70 antibody levels induced by acute myocardial infarction (AMI). Plasma Hsp70 and anti-Hsp70 antibody levels in 291 patients with ACS (179 AMI, 112 unstable angina), 126 patients with SA and 417 age and sex-matched healthy subjects, and in 40 patients after admission for AMI, and on day 2, 3, and 7 after the onset of AMI were determined using enzyme-linked immunosorbent assays. Hsp70 levels were significantly higher in ACS and SA and anti-Hsp70 antibody levels were only markedly lower in ACS than controls. After adjustment for traditional CHD risk factors, increasing levels of Hsp70 were significantly associated with an increased risk and severity of ACS (P for trend < 0.001), whereas increasing levels of anti-Hsp70 antibody were associated with a decreased risk of ACS (P for trend = 0.0003). High levels of Hsp70 combined with low levels of anti-Hsp70 antibody had a joint effect on the risk of ACS (OR, 5.14, 95% CI, 3.00-8.79; P < 0.0001). In patients with AMI, Hsp70 levels decreased rapidly from days 1-7 after onset, whereas anti-Hsp70 antibody levels increased in patients with AMI. These findings suggest that higher Hsp70 levels or lower anti-Hsp70 antibody levels are independently associated with a higher risk of ACS. Higher Hsp70 levels and lower anti-Hsp70 antibody levels combine to further increase this risk.

Elevated heat shock protein 60 levels are associated with higher risk of coronary heart disease in Chinese.

Background— Although heat shock protein 60 (Hsp60) is implicated in the pathogenesis of atherosclerosis, its role in coronary heart disease (CHD) is uncertain. This study explored the influence of circulating Hsp60 on CHD in a large case-control study, as well as the impact of acute myocardial infarction on Hsp60 levels in a prospective study. Methods and Results— Plasma Hsp60 and anti-Hsp60 antibody levels were determined by immunoassay. In the case-control study (1003 patients with CHD, 1003 matched control subjects), Hsp60 levels were higher in patients with CHD and were related to CHD (OR comparing extreme quartiles=4.14, P<0.0001). This association remained after adjustment for traditional risk factors (P for trend <0.0001). Individuals having high levels of Hsp60 (greater than the median of 160.24 ng/mL) and anti-Hsp60 antibody (greater than the median of 38.42 U/mL) were at a greater risk of CHD than those with low levels (OR 2.30, P<0.0001). Stronger additive effects (OR 14.04, P<0.0001) were apparent at higher Hsp60 and anti-Hsp60 antibody levels (>1000 ng/mL and greater than the median of 38.42 U/mL, respectively). The simultaneous presence of high Hsp60 and anti-Hsp60 antibody levels, current smoking, hypertension, and diabetes were cumulatively associated with CHD. Individuals who had any 4 or more of these 5 factors had an OR of 38.61 for CHD (P<0.0001) compared with individuals who had none of these factors. For the prospective study, blood was drawn from 20 patients immediately after admission for acute myocardial infarction and 2, 3, and 7 days thereafter. Hsp60 levels were significantly higher on the day of and the day after arrival than 7 days after an acute myocardial infarction (P=0.011 and P=0.026, respectively). Conclusions— Elevated Hsp60 levels are associated with an increased risk for CHD, and Hsp60 and anti-Hsp60 antibody levels combine to increase this risk. In addition, acute myocardial infarction induces Hsp60 release.

Serum and lymphocyte levels of heat shock protein 70 in aging: a study in the normal Chinese population

Abstract Heat shock proteins (Hsps) have been reported to play an important role in both physiological and pathological processes. Hsps also may serve as biomarkers for evaluating disease states and exposure to environmental stresses. Whether Hsp levels in serum and lymphocytes are correlated with age and sex is largely unknown. In this study, we analyzed serum Hsp70 (the most abundant mammalian Hsp) levels by using Western dot blot in 327 healthy male donors aged between 15 and 50 years. We also investigated the association between Hsp70 levels and age in lymphocytes of 80 normal individuals aged between 40 and 77 years because various chronic diseases increase after the age of 40 years. Our data showed that serum Hsp70 levels were positively correlated with age in subjects aged between 15 and 30 years (P < 0.05) but negatively correlated with age in subjects aged between 30 and 50 years (P < 0.05). Serum Hsp70 levels were the highest in individuals aged between 25 and 30 years among all age groups. In the lymphocyte study there also was a significant age-related decrease in Hsp70 levels in lymphocytes of individuals older than 40 years. The Hsp70 levels were negatively correlated with age (r = −3.708, P < 0.0001) but not with sex (r = −10.536, P = 0.452). This suggests that both serum and lymphocyte Hsp70 levels are age-related and that these may be linked to age-related stress. Thus, age is an important factor in using serum and lymphocyte Hsp70 as biomarkers to evaluate the disease states or exposure to environmental stresses (or both).

Functional SNPs in HSPA1A gene predict risk of coronary heart disease.

Background HSP70 plays crucial roles in endothelial cell apoptosis, which is involved in the early phase and progress of coronary heart disease (CHD). However, the association between polymorphisms of HSP70 genes and the risk of CHD still remains unclear. Our aim was to determine whether genetic variants in the HSPA1A gene are associated with the risk of CHD. Methodology/Principal Findings By resequencing and genotyping, the associations of 2 single nucleotide polymorphisms (SNPs) +190G/C (rs1043618) and −110A/C (rs1008438) in the HSPA1A gene with risk of CHD were determined in a 1,003 pairs case-control study. The SNP function was further analyzed using a luciferase reporter assay in two cell lines. The results indicated that +190CC genotype was associated with significantly higher risk of CHD when compared with +190GG genotype (OR = 1.56, 95% CI: 1.10–2.20, P = 0.012), while association between −110A/C polymorphism and CHD was not statistically significant (P>0.05). However, the −110C/+190C haplotype had a significantly higher risk of CHD when compared with the −110A/+190G haplotype (OR = 1.17, 95% CI: 1.01–1.34, P = 0.031). Luciferase reporter assays showed that the +190C allele resulted in 14%∼45% reduction in luciferase expression in endothelial and non-endothelial cells when compared with the +190G allele. Conclusions/Significance The identified genetic variants in the HSPA1A gene combinatorially contribute towards the susceptibility to CHD likely by affecting the level of synthesis of HSP70. This study may provide useful markers for identification of subjects at risk for CHD.

Circulating MicroRNAs and the Occurrence of Acute Myocardial Infarction in Chinese Populations

Background—Circulating microRNAs ( miRNAs) are emerging as novel disease biomarkers. We aimed to explore the association between circulating miRNAs and the occurrence of acute myocardial infarction (AMI) in Chinese populations. Methods and Results—In the discovery stage, the plasma of 20 patients with AMI and 20 controls were pooled respectively and profiled by massively parallel sequencing. Seventy-seven miRNAs showed differential expression. Selected miRNAs were validated in 178 patients with AMI and 198 controls using quantitative reverse transcriptase polymerase chain reaction assays and further replicated in 150 patients with AMI and 150 controls. Results suggest that miR-320b and miR-125b levels were significantly lower in patients with AMI than in controls in both validation populations (P<0.0001). Lower levels of miR-320b and miR-125b were associated with increased occurrence of AMI (adjusted odds ratio, 4.71; 95% confidence interval, 2.96–7.48 and odds ratio, 4.27; 95% confidence interval, 2.84–6.41, respectively). Addition of the 2 miRNAs to traditional risk factors led to a significant improvement in the area under the curve from 0.822 (95% confidence interval, 0.787–0.856) to 0.871 (95% confidence interval, 0.842–0.900), with a net reclassification improvement of 20.45% (P<0.0001) and an integrated discrimination improvement of 0.16 (P<0.0001) for patients with AMI. A functional study showed that miR-320b and miR-125b could regulate the expression profiles of genes enriched in several signal transduction pathways critical for coronary heart disease in human vascular endothelial cells. Conclusions—The plasma levels of miR-320b and miR-125b were significantly lower in patients with AMI when compared with controls, and these miRNAs may be involved in the pathogenesis of coronary heart disease.

Genetic Variants at Newly Identified Lipid Loci Are Associated with Coronary Heart Disease in a Chinese Han Population

Background Recent genome-wide association studies (GWAS) have mapped several novel loci influencing blood lipid levels in Caucasians. We sought to explore whether the genetic variants at newly identified lipid-associated loci were associated with CHD susceptibility in a Chinese Han population. Methodology/Principal Findings We conducted a two-stage case-control study in a Chinese Han population. The first-stage, consisting of 1,376 CHD cases and 1,376 sex and age- frequency matched controls, examined 5 novel lipid-associated single-nucleotide polymorphisms (SNPs) identified from GWAS among Caucasians in relation to CHD risk in Chinese. We then validated significant SNPs in the second-stage, consisting of 1,269 cases and 2,745 controls. We also tested associations between SNPs within the five novel loci and blood lipid levels in 4,121 controls. We identified two novel SNPs (rs599839 in CELSR2-PSRC1-SORT1 and rs16996148 in NCAN-CILP2) that were significantly associated with reduced CHD risk in Chinese (odds ratios (95% confidence intervals) in the dominant model 0.76 (0.61-0.90; P = 0.001), 0.67 (0.57-0.77; P = 3.4×10−8), respectively). Multiple linear regression analyses using dominant model showed that rs599839 was significantly associated with decreased LDL levels (P = 0.022) and rs16996148 was significantly associated with increased LDL and HDL levels (P = 2.9×10−4 and 0.001, respectively). Conclusions/Significance We identified two novel SNPs (rs599839 and rs16996148) at newly identified lipid-associated loci that were significantly associated with CHD susceptibility in a Chinese Han population.

Expression of heat shock proteins in myocardium of patients with atrial fibrillation

Abstract Atrial fibrillation (AF) is the most common sustained arrhythmia. Because heat shock proteins (Hsp) can protect cells from stress, we compared the levels of Hsp60, Hsp72, Hsc73, and Hsp27 in atrial myocardium from 17 patients with AF (8 paroxysmal and 9 persistent) and 7 controls in sinus rhythm (SR). Hsp60, Hsp72, and Hsc73 levels were not significantly different among the 3 groups. Hsp27 expression was slightly higher in paroxysmal AF than in SR and in persistent AF, and a borderline significant difference (P = 0.064) was seen between the paroxysmal and persistent AF subgroups. Hsp60 levels in the moderate, severe, and profound myolysis groups were significantly lower than the light myolysis group, but no differences were found in other Hsps. In summary, the data indicate that expression of Hsp27 and Hsc73 may be associated with different stages of AF and that Hsp60 also may be associated with the degree of atrial myolysis.

Curcumin serves as a human kv1.3 blocker to inhibit effector memory T lymphocyte activities.

Curcumin, the principal active component of turmeric, has long been used to treat various diseases in India and China. Recent studies show that curcumin can serve as a therapeutic agent for autoimmune diseases via a variety of mechanisms. Effector memory T cells (TEM, CCR7‐CD45RO+ T lymphocyte) have been demonstrated to play a crucial role in the pathogenesis of T cell‐mediated autoimmune diseases, such as multiple sclerosis (MS) or rheumatoid arthritis (RA). Kv1.3 channels are predominantly expressed in TEM cells and control TEM activities. In the present study, we examined the effect of curcumin on human Kv1.3 (hKv1.3) channels stably expressed in HEK‐293 cells and its ability to inhibit proliferation and cytokine secretion of TEM cells isolated from patients with MS or RA. Curcumin exhibited a direct blockage of hKv1.3 channels in a time‐dependent and concentration‐dependent manner. Moreover, the activation curve was shifted to a more positive potential, which was consistent with an open‐channel blockade. Paralleling hKv1.3 inhibition, curcumin significantly inhibited proliferation and interferon‐γ secretion of TEM cells. Our findings demonstrate that curcumin is able to inhibit proliferation and proinflammatory cytokine secretion of TEM cells probably through inhibition of hKv1.3 channels, which contributes to the potency of curcumin for the treatment of autoimmune diseases. This is probably one of pharmacological mechanisms of curcumin used to treat autoimmune diseases. Copyright

The Antibody Targeting the E314 Peptide of Human Kv1.3 Pore Region Serves as a Novel, Potent and Specific Channel Blocker

Selective blockade of Kv1.3 channels in effector memory T (TEM) cells was validated to ameliorate autoimmune or autoimmune-associated diseases. We generated the antibody directed against one peptide of human Kv1.3 (hKv1.3) extracellular loop as a novel and possible Kv1.3 blocker. One peptide of hKv1.3 extracellular loop E3 containing 14 amino acids (E314) was chosen as an antigenic determinant to generate the E314 antibody. The E314 antibody specifically recognized 63.8KD protein stably expressed in hKv1.3-HEK 293 cell lines, whereas it did not recognize or cross-react to human Kv1.1(hKv1.1), Kv1.2(hKv1.2), Kv1.4(hKv1.4), Kv1.5(hKv1.5), KCa3.1(hKCa3.1), HERG, hKCNQ1/hKCNE1, Nav1.5 and Cav1.2 proteins stably expressed in HEK 293 cell lines or in human atrial or ventricular myocytes by Western blotting analysis and immunostaining detection. By the technique of whole-cell patch clamp, the E314 antibody was shown to have a directly inhibitory effect on hKv1.3 currents expressed in HEK 293 or Jurkat T cells and the inhibition showed a concentration-dependence. However, it exerted no significant difference on hKv1.1, hKv1.2, hKv1.4, hKv1.5, hKCa3.1, HERG, hKCNQ1/hKCNE1, L-type Ca2+ or voltage-gated Na+ currents. The present study demonstrates that the antibody targeting the E314 peptide of hKv1.3 pore region could be a novel, potent and specific hKv1.3 blocker without affecting a variety of closely related Kv1 channels, KCa3.1 channels and functional cardiac ion channels underlying central nervous systerm (CNS) disorders or drug-acquired arrhythmias, which is required as a safe clinic-promising channel blocker.