无关供者异基因造血干细胞移植中急性移植物抗宿主病与肿瘤坏死因子基因多态性的关系

目的 探讨无关供者异基因造血干细胞移植(allo-HSCT)患者及其干细胞供者的肿瘤坏死因子(TNF)单核苷酸多态性(SNP)与急性移植物抗宿主病(aGVHD)之间的关系.方法 回顾性分析浙江大学医学院附属第一医院移植中心接受无关供者allo-HSCT患者及其供者,共76对,采用多重单碱基延伸SNP分型技术检测TNF基因5个位点的SNP(TNFα-238、TNFα-857、TNFα-863、TNFα-1031、TNFβ+252),分析与aGVHD的发生风险、临床严重程度之间的关系.结果 在23例发生Ⅱ-Ⅳ度aGVHD患者中,其干细胞供者基因型TNFα-857 CC的频率(91.3%)高于基因型CT(8.7%)(P=0.039);TNFβ+252(A/G)位点未检出从基因型,19例患者为GA基因型(82.6%),4例患者为GG基因型(17.4%),3组之间比较差异有统计学意义(P=0.006).而患者与干细胞供者TNFα-238(G/A)、TNFα-863(C/A)和TNFα-1031(T/C)位点的基因多态性均未发现与aGVHD的发生风险相关.结论 干细胞供者TNFα-857 CC基因型与Ⅱ～Ⅳ度aGVHD的发生密切相关,而TNFβ+252为AA基因型的患者不易发生Ⅱ～Ⅳ度aGVHD.     

Ryanodine receptor as a new therapeutic target of heart failure and lethal arrhythmia.

Abnormal intracellular Ca(2+) handling by the sarcoplasmic reticulum (SR) is a critical factor in the development of heart failure (HF). Not only decreased Ca(2+) uptake, but also uncoordinated Ca(2+) release plays a significant role in contractile and relaxation dysfunction. Spontaneous Ca(2+) release through ryanodine receptor (RyR) 2, a huge tetrameric protein, during diastole leads to a decrease in the SR Ca(2+) content, and also triggers delayed after depolarization that is a substrate for lethal arrhythmia. Several disease-linked mutations of RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrhythmogenic right ventricular cardiomyopathy type 2 (ARVC2). The unique distribution of these mutation sites has lead to the concept that an interaction among the putative regulatory domains within RyR may play a key role in regulating channel opening, and that there seems to be a common abnormality in the channel disorder of HF and CPVT/ARVC2. Recent knowledge gained from pathological conditions may lead to the development of a new therapeutic strategy for the treatment of HF or cardiac arrhythmia.     

A mutation in the transmembrane/luminal domain of the ryanodine receptor is associated with abnormal Ca2+ release channel function and severe central core disease

Central core disease is a rare, nonprogressive myopathy that is characterized by hypotonia and proximal muscle weakness. In a large Mexican kindred with an unusually severe and highly penetrant form of the disorder, DNA sequencing identified an I4898T mutation in the C-terminal transmembrane/luminal region of the RyR1 protein that constitutes the skeletal muscle ryanodine receptor. All previously reported RYR1 mutations are located either in the cytoplasmic N terminus or in a central cytoplasmic region of the 5,038-aa protein. The I4898T mutation was introduced into a rabbit RYR1 cDNA and expressed in HEK-293 cells. The response of the mutant RyR1 Ca2+ channel to the agonists halothane and caffeine in a Ca2+ photometry assay was completely abolished. Coexpression of normal and mutant RYR1 cDNAs in a 1:1 ratio, however, produced RyR1 channels with normal halothane and caffeine sensitivities, but maximal levels of Ca2+ release were reduced by 67%. [3H]Ryanodine binding indicated that the heterozygous channel is activated by Ca2+ concentrations 4-fold lower than normal. Single-cell analysis of cotransfected cells showed a significantly increased resting cytoplasmic Ca2+ level and a significantly reduced luminal Ca2+ level. These data are indicative of a leaky channel, possibly caused by a reduction in the Ca2+ concentration required for channel activation. Comparison with two other coexpressed mutant/normal channels suggests that the I4898T mutation produces one of the most abnormal RyR1 channels yet investigated, and this level of abnormality is reflected in the severe and penetrant phenotype of affected central core disease individuals.     

致心律失常性右心室心肌病患者桥粒斑蛋白基因突变和单核苷酸多态性检测

目的 调查致心律失常性右心室心肌病（ARVC）患者桥粒斑蛋白（DSP）基因突变和单核苷酸多态性（SNPs）发生率.方法 对初步诊断为ARVC的50例患者采用2010年新诊断标准予以重新评估.应用聚合酶链式反应（PCR）扩增DSP基因全部外显子片段并测序,病例组测序结果与198例正常对照组进行比对分析.结果 37例符合ARVC确诊病例,9例为临界诊断病例,另有4例为疑似诊断病例.确诊病例中有5例（14％）携带5种DSP基因突变,既往均未见报道,包括4种错义突变和1种无义突变,临界诊断与疑似诊断病例均未检出DSP基因突变.同时检出4个非同义SNPs位点,其等位基因频率在对照组和病例组间差异无统计学意义.结论 本组ARVC患者DSP基因突变检出率为14％,且均为新发现突变.DSP基因外显子区域的4个SNPs位点可能与ARVC的发病无相关性.     

Lack of an association between interleukin-12 receptor beta1 polymorphisms and tuberculosis in Koreans

BACKGROUND: The fact that only 10% of people infected with Mycobacterium tuberculosis develop clinical tuberculosis (TB) suggests the presence of genetic factors in the pathogenesis of TB. To date, a number of single nucleotide polymorphisms (SNPs) in several candidate genes have been proposed as genetic risk factors of TB; however, reports are conflicting. OBJECTIVES: We investigated whether SNPs in the interleukin (IL)-12 receptor beta1 gene are associated with TB in Koreans. METHODS: One hundred and fifteen patients with bacteriologically or pathologically confirmed TB and 151 healthy anonymous blood donors were enrolled. The genotypes of 5 SNPs on IL-12 receptor beta1 gene, +705A/G (Q214R), +1158T/C (M365T), +1196G/C (G378R), +1637G/A (A525T) and +1664 C/T (P534S), were determined by PCR-RFLP. RESULTS: No difference was observed between TB patients and controls in terms of the genotype frequencies of the 5 SNPs of the IL-12 receptor beta1 gene or of their haplotypes. CONCLUSIONS: In view of the finding that these SNPs have been reported to be associated with TB in the Japanese and Moroccan populations, our results may reflect racial differences in genetic susceptibility to TB.     

扩张型心肌病患者CD4~+CD25~+Foxp3~+ T细胞的检测及意义

目的:探讨扩张型心肌病(DCM)患者外周血CD4+CD25+Foxp3+T细胞的水平及意义。方法:采用流式细胞术检测DCM患者30例及健康对照组20例外周血CD4+CD25+T细胞和CD4+CD25+Foxp3+T细胞的比例。结果:DCM患者外周血CD4+CD25+T细胞占CD4+T细胞的比例为(8.53±1.64)%,显著低于健康对照组的(11.4±2.17)%,P0.01;DCM患者CD4+CD25+Foxp3+T细胞占CD4+T细胞比例为(0.99±0.54)%,显著低于健康对照组的(1.55±0.55)%,P0.01;且DCM患者心功能越差,CD4+CD25+Foxp3+T细胞占CD4+T细胞的比例越低。结论:DCM患者调节性T细胞比例的减少,可能打破了自身免疫耐受,发生了针对心肌抗原的自身免疫反应,参与了DCM的发病。     

Susceptibility to ankylosing spondylitis: no evidence for the involvement of transforming growth factor beta 1 (TGFB1) gene polymorphisms

BACKGROUND: Genetic factors are thought to be crucial in the pathogenesis of ankylosing spondylitis. Transforming growth factor beta 1 (TGF beta 1) is a multifunctional cytokine that plays a key role in inflammation. Two functional single nucleotide polymorphisms (SNPs) in the TGFB1 gene have been described: TGFB1 T869C and TGFB1 G915C. OBJECTIVE: To determine whether these SNPs contribute to ankylosing spondylitis susceptibility or its disease characteristics. METHODS: Genomic DNA was isolated from the peripheral blood of 134 patients with ankylosing spondylitis and 194 healthy blood donors. All subjects were unrelated and of white Dutch ethnicity. The diagnosis of ankylosing spondylitis was made according to the modified New York criteria. The TGFB1 T869C and TGFB1 G915C SNPs were genotyped by a polymerase chain reaction-single strand conformation polymorphism haplotyping method. RESULTS: No significant differences were found between patients and controls in genotype, allele, and haplotype frequencies or in the carrier rate of the rare alleles of the TGFB1 T869C and TGFB1 G915C SNPs. CONCLUSIONS: TGFB1 T869C and TGFB1 G915C SNPs are not major factors in the susceptibility to ankylosing spondylitis or its disease characteristics.     

Genetic association study of adiponectin polymorphisms with risk of Type 2 diabetes mellitus in Korean population.

AIMS: To investigate any association between Type 2 diabetes mellitus and two single nucleotide polymorphisms (SNPs) in the adiponectin gene, T45G and G276T, in the Korean population. METHODS: We genotyped 427 non-diabetic controls and 493 Type 2 diabetic patients for SNPs T45G and G276T of adiponectin gene, measured plasma adiponectin concentrations, and examined clinical parameters in Koreans. RESULTS: There were no statistically significant differences in allele frequencies of SNPs 45 and 276 comparing control with Type 2 diabetic subjects (T frequency 68.3% vs. 71.6%, P=0.13 for SNP45, G frequency 72.2% vs. 68.9%, P=0.12 for SNP276). The genotype distributions of these SNPs had no association with the risk of Type 2 diabetes and metabolic parameters of insulin resistance. Plasma levels of adiponectin were not statistically different according to T45G and G276T either, in both control and Type 2 diabetic subjects. CONCLUSION: The T45G and G276T of the adiponectin gene may not be an important determinant of Type 2 diabetes or insulin resistance in Korean subjects.     

MicroRNA gene polymorphisms in pancreatic cancer

MicroRNAs (miRNAs) act as regulators of gene expression via translational repression. Single nucleotide polymorphisms (SNPs) in miRNAs have been shown to affect the regulatory capacity of miRNAs by influencing miRNA processing and/or miRNA-mRNA interactions. The purpose of this study was to investigate the association between 2 SNPs commonly found in precursor miRNA and the susceptibility and clinicopathological characteristics of pancreatic cancer. The rs11614913/miR-196a2, rs2910164/miR-146a SNPs were genotyped in 93 patients with pancreatic cancer and in 122 healthy controls. No significant differences in genotype distributions between controls and PC patients were observed. However, rs2910164 GG and rs11614913 CC genotypes and the rs2910164C/rs11614913C and rs2910164G/rs11614913C haplotypes were significantly overrepresented in PC patients with T1 and T2 tumor status than in those with T3 and T4. Our findings suggested that the rs2910164 and rs11614913 SNPs might play a role in pancreatic tumorigenesis, but the molecular mechanism underlying the particular sequence variations in miRNA that can cause aberrant expression remains to be determined.     

Functional SNP in the microRNA-367 binding site in the 3'UTR of the calcium channel ryanodine receptor gene 3 (RYR3) affects breast cancer risk and calcification

We have evaluated and provided evidence that the ryanodine receptor 3 gene (RYR3), which encodes a large protein that forms a calcium channel, is important for the growth, morphology, and migration of breast cancer cells. A putative binding site for microRNA-367 (miR-367) exists in the 3'UTR of RYR3, and a genetic variant, rs1044129 A→G, is present in this binding region. We confirmed that miR-367 regulates the expression of a reporter gene driven by the RYR3 3'UTR and that the regulation was affected by the RYR3 genotype. A thermodynamic model based on base pairing and the secondary structure of the RYR3 mRNA and miR-367 miRNA showed that miR-367 had a higher binding affinity for the A genotype than for the G genotype. The rs1044129 SNP was genotyped in 1,532 breast cancer cases and 1,600 healthy Chinese women. The results showed that compared with the AA genotype, G was a risk genotype for breast cancer development and was also associated with breast cancer calcification and poor survival. Thus, rs1044129 is a unique SNP that resides in a miRNA-gene regulatory loop that affects breast cancer risk, calcification, and survival.     

Haplotype analysis in simplex families and novel analytic approaches in a case-control cohort reveal no evidence of association of the CTLA-4 gene with rheumatoid arthritis

OBJECTIVE: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a negative regulator of T cells and is, therefore, a strong candidate susceptibility gene for T cell-mediated autoimmune diseases. The association of CTLA-4 single-nucleotide polymorphisms (SNPs) with rheumatoid arthritis (RA) has been investigated previously, with inconsistent results. Recently, SNPs mapping to the gene (and not previously investigated in RA) have been associated with both type 1 diabetes mellitus and Graves' disease. The aim of this study was to investigate the association of the CTLA-4 polymorphism with RA. METHODS: Primer extension methods were used to genotype 5 haplotype-tagging SNPs (htSNPs) (-1722 T/C, -1661 A/G, -658 C/T, -319 C/T, and +49 A/G), and the TaqMan 5' allelic discrimination assay was used to genotype an additional 2 SNPs (CT60 and rs1863800) mapping to the CTLA-4 gene. Association to the 5 htSNPs was investigated using the transmission disequilibrium test in RA simplex families (n = 122). Allele frequencies for the htSNPs were also investigated in affected sibling pairs (n = 96) and unrelated controls (n = 173). For the SNPs CT60 and rs1863800, unrelated patients with RA (n = 759) were compared with controls (n = 755). RESULTS: No evidence for association to single markers or haplotypes of the 5 htSNPs was detected in either RA simplex families or the affected sibling-control cohort. Neither of the 2 SNPs recently associated with Graves' disease showed evidence for association in the unrelated patient-control cohort. CONCLUSION: No evidence for association of CTLA-4 with RA was detected using family or case-control methods.     

The genetic basis of cardiomyopathy

Cardiomyopathies are the primary disorders of cardiac myocytes, and their cause is usually genetic. The three common forms are hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC). Mutations in sarcomeric proteins typically cause HCM and, less commonly, DCM. Mutations in cytoskeletal proteins cause DCM, and those in desmosomal proteins cause ARVC. The pathways from mutations to the clinical phenotype could be categorized into three stages of initial functional defects leading to expression and activation of molecular events that mediate development of morphologic and structural phenotypes. Advances in understanding the molecular genetics and pathogenesis of cardiomyopathies could provide the opportunity for preclinical diagnosis and interventions to prevent, attenuate, or reverse the evolving phenotypes.     

脂联素基因SNPs＋45T＞G和SNPs＋276G＞T与老年非糖尿病冠心病的相关性

目的探讨老年人脂联素基因SNPs＋45T〉G和SNPs＋276G〉T与老年非糖尿病冠心病的相关性。方法选择2005年11月至2009年12月人住我院心血管内科病房,行冠状动脉造影、年龄≥65岁的非糖尿病患者688例,根据冠状动脉造影结果分为冠心病组396例和对照组292例。采用聚合酶链式反应／连接酶检测反应方法检测多态性位点。结果SNPs＋45T〉G基因表型为突变型GG者发生冠心病的危险性较TT型者显著增加（OR=2．65,P〈0．01）;SNPs＋276G〉T基因表型为GG型者发生冠心病的危险性较TT型者显著增加（OR=2．36,P〈0．01）;杂合子GT型者发生冠心病的危险陛也较TT型者显著增加（OR=1．66,P〈0．05）。logistic回归分析显示,SNPs＋45T〉G基因表型为GG型,SNPs＋276G〉T基因表型为GG和GT型是冠心病发病独立的危险因素。SNPs＋45T〉G和SNPs＋276G〉T位点存在连锁不平衡,脂联素基因SNPs＋45T〉G基因表型为突变型GG型者SNPs＋276G〉T基因表型均为GG型,而SNPs＋276G〉T基因表型为突变型TT型者SNPs＋45T〉G基因表型均为TT型,即GGGG基因表型和TTTT基因表型,且SNPs＋45T〉G和SNPs＋276G〉T位点基因表型为GGGG型者发生冠心病的危险性显著高于TTTT型者（OR=4．77,P〈0．01）。结论在老年非糖尿病者中,脂联素基因SNPs＋45T〉G基因表型为GG型者和SNPs＋276G〉T基因表型为GG或GT型者可能是冠心病的易感人群。     

心脏型肌球蛋白结合蛋白C基因13261 G＞A突变导致肥厚型心肌病的临床表型分析

目的研究中国人肥厚型心肌病致病基因,分析基因型与临床表型的关系。方法在一肥厚型心肌病家系中进行心脏型肌球蛋白结合蛋白C基因（MYBPC3）和β-肌球蛋白重链基因（MYH7）突变筛查,利用聚合酶链反应（PCR）扩增其功能区的外显子片段,双脱氧末段终止法测序。家系调查资料包括临床表现、体格检查、心脏超声和心电图。结果在该家系27例有血缘关系的研究对象中9例携带MYBPC3 13261 G〉A（G758D）突变,正常对照组同一位置未见异常。该突变位点是MYBPC3基因第23号外显子的甘氨酸突变为天冬氨酸,其中2例携带者发病,一例表现为心室扩大,左室射血分数减低等扩张型心肌病样表现,伴室间隔不对称肥厚,厚度为14mm,另外一例患者为典型的肥厚型心肌病表现。MYH7基因未发现突变。结论MYBPC3基因13261 G〉A突变是该肥厚型心肌病家系的致病突变,其外显率为22％,其中一例患者表现为肥厚型心肌病的扩张相,MYBPC3基因G758D突变可能是肥厚型心肌病进展为扩张型心肌病样改变的原因之一。对临床表现为扩张型心肌病的患者进行家族史调查及基因检查十分必要。     

Cytokine genotypes correlate with pain and radiologically defined joint damage in patients with juvenile rheumatoid arthritis

OBJECTIVES: Single nucleotide polymorphisms (SNPs) in cytokine genes have been associated with risk of a number of autoimmune diseases. Moreover, some SNPs are associated with variations in rates of in vitro gene expression, and it is therefore possible that these functional polymorphisms may differentially affect inflammatory processes and disease outcome. This project's objective was to determine whether cytokine genotypes correlate with disease outcomes in patients with juvenile rheumatoid arthritis (JRA). METHODS: Genotypes of SNPs of pro-inflammatory cytokines, tumour necrosis factor-alpha -308G -->A, interleukin-6 (IL-6) -174G -->C and interferon-gamma +874G -->A, and anti-inflammatory, immunosuppressive cytokines, interleukin-10 -1082G -->A, -819C -->T and -592A -->C and transforming growth factor-beta1 (TGF-beta1) codon 10T -->C and codon 25G -->C, were determined for patients with JRA who previously participated in a long-term outcome study. Cytokine genotypes and clinical variables showing significant correlations with clinical outcomes at the alpha = 0.100 level in univariate analyses were entered in multivariate tests. RESULTS: In multivariate tests, the IL-6 genotype -174G/G was positively correlated with pain [regression coefficient B = 0.899, 95% confidence intervals (CI) 0.185, 1.612, P = 0.014]. The homozygous TGF-beta1 codon 25G/G genotype showed a protective effect against joint space narrowing on radiographs taken within 2 yr of disease onset, but confidence intervals were wide [odds ratio (OR) 0.176, 95% CI 0.037, 0.837 P = 0.029]. CONCLUSIONS: The correlation of IL-6 genotype with pain and the possible association of the TGF-beta1 codon 25 genotype with short-term radiographic damage (G/C with greater risk and G/G with decreased risk) suggests that both these polymorphisms may be useful early prognostic indicators. Further studies of the relation between cytokine genotypes and outcomes in patients with all forms of juvenile idiopathic arthritis (JIA) are warranted.     

扩张型心肌病患者外周血CD4＋CD25＋T细胞变化及临床意义

目的探讨扩张型心肌病（DCM）患者外周血CD4＋CD2＋5T细胞变化及临床意义。方法采用流式细胞分析法检测30例DCM患者（DCM组）及20例健康者（对照组）的外周血CD4＋CD2＋5T细胞。结果外周血CD4＋CD2＋5T细胞占CD4＋T细胞的比例DCM组为（8.53±1.64）%,对照组为（11.4±2.17）%,两组比较有统计学差异（P〈0.01）;且DCM患者心功能越差,CD4＋CD2＋5T细胞占CD4＋T细胞的比例越低。结论DCM患者CD4＋CD2＋5T细胞比例减少,可能打破自身免疫耐受,发生针对心肌抗原的免疫反应,参与DCM发病。     

Cytokine Gene Polymorphisms in Iranian Patients with Beta-Thalassemia Major

Background: β-thalassemia as a hereditary disease is defined as defective synthesis of   β-globin chains, resulting in erythropoiesis abnormalities and severe anemia. Different studies have shown that cytokines and cytokine gene polymorphisms play a major role in the pathogenesis of   β-thalassemia. Single nucleotide polymorphisms (SNPs) within the promoter region or other regulatory sequences of cytokine genes lead to overall production of cytokines.   Objective: To analyze the genetic profile of Th1 and Th2 cytokines in Iranian patients with   β-thalassemia major. Methods: Allelic and genotype frequencies of cytokine genes were determined in 30 thalassemia patients and 40 healthy subjects using PCR-SSP assay. Allele and genotype frequencies were calculated and compared with those of normal controls.   Results: The results of our study show a significant decrease in A allele at position UTR 5644 IFN-   γ, G alleles at position -238 TNF-   α and 166 IL-2, and C allele at position -590 IL-4. TGF- β   haplotype TG/TG increased whereas TGF-β haplotype CG/CG and IL-10 haplotype GCC/ACC decreased significantly in all patients.   Conclusion: Data of this investigation suggest that variations among cytokine gene polymorphisms may contribute to the disease susceptibility. A finding which needs to be fairly clarified in other ethnic groups.     

Myocardial Inflammation and Sudden Death in the Inherited Cardiomyopathies

The best studied of the inherited cardiomyopathies—hypertrophic (HCM), dilated (DCM) and arrhythmogenic (ACM)—present overlapping clinical phenotypes with varying, often unrecognized, risk of sudden death. Risk assessment is informed by patient sex and by the specific disease-causing variant. HCM and arrhythmogenic right ventricular cardiomyopathy (ARVC) remain important causes of sudden death. A phenotype mimicking DCM in patients with inherited ACM is associated with premature sudden death in families with overlapping DCM and ACM phenotypes. The role of inflammation as a determinant of disease development and progression and sudden death is poorly understood but potentially important. Sudden death registries report myocarditis as the cause in 5% to 13%; examination of 30 hearts from victims of ARVC sudden death found focal myocarditis in areas of myocyte necrosis in 20 (67%). The link to specific disease-causing variants remains to be explored, including genetic determinants of the immune response. Clinical and experimental studies support immune- and autoimmune-mediated disease in DCM and ACM. Immunosuppression in biopsy-proven noninfectious myocarditis and inflammatory DCM is a treatment option. Recognition of ACM requires greater focus on distinguishing ACM from DCM. The potential to recognize disease before adverse events and to characterize patients who may benefit from immunosuppression or device therapy highlights the importance of more comprehensive genetic and immunologic characterization of patients with myocarditis and in those with a family history or clinical presentation of an inherited cardiomyopathy. This review will examine from a predominantly clinical perspective the potential importance of myocardial inflammation as a determinant of sudden death in inherited HCM, DCM, and ACM.     

Magnetic resonance imaging findings in suspected arrhythmogenic right ventricular dysplasia.

INTRODUCTION: Cardiac magnetic resonance imaging (CMRI) has been used to evaluate right ventricular morphology in suspected arrhythmogenic right ventricular cardiomyopathy (ARVC). We report qualitative CMRI findings in patients with suspected ARVD. METHODS: A retrospective review of images in 35 patients referred for CMRI with clinically suspected ARVD. RESULTS: Eleven patients were considered to have alterations on CMRI. In 5 patients a dilated outflow tract and/or right ventricle was identified; a high intramyocardial T1 fat signal was identified in one patient, regional dyskinesia in two patients, and small excavated pouches in 4 patients. Prominent right ventricular trabeculae were present in 4 patients. CONCLUSIONS: CMRI alterations used for diagnosis of ARVC were identified in approximately one-third of patients referred to our center with either clinical suspicion or diagnosis of ARVC.     

Does nitric oxide modulate cardiac ryanodine receptor function? Implications for excitation-contraction coupling

Nitric oxide (NO) is a highly reactive, free radical signalling molecule that is constitutively released in cardiomyocytes by both the endothelial and neuronal isoforms of nitric oxide synthase (eNOS and nNOS, respectively). There are increasing data indicating that NO modulates various proteins involved in excitation-contraction coupling (ECC), and here we discuss the evidence that NO may modulate the function of the ryanodine receptor Ca(2+) release channel (RyR2) on the cardiac sarcoplasmic reticulum (SR). Both constitutive isoforms of NOS have been shown to co-immunoprecipitate with RyR2, suggesting that the channel may be a target protein for NO. eNOS gene deletion has been shown to abolish the increase in spontaneous Ca(2+) spark frequency in cardiomyocytes exposed to sustained stretch, whereas the effect of nNOS-derived NO on RyR2 function remains to be investigated. Single channel studies have been performed with RyR2 reconstituted in planar lipid bilayers and exposed to various NO donors and, under these conditions, NO appears to have a dose-dependent, stimulatory effect on channel open probability (P(open)). We discuss whether NO has a direct effect on RyR2 via covalent S-nitrosylation of reactive thiol residues within the protein, or whether there are downstream effects via cyclic nucleotides, phosphodiesterases, and protein kinases. Finally, we consider whether the proposed migration of nNOS from the SR to the sarcolemma in the failing heart may have consequences for the nitrosative vs. oxidative balance at the level of the RyR2, and whether this may contribute to an increased diastolic Ca(2+) leak, depleted SR Ca(2+) store, and reduced contractility in heart failure.