Study Populations
The China Patient-centered Evaluative Assessment of Cardiac Events Prospective Heart Failure Study (China PEACE 5p-HF Study) enrolled patients hospitalized primarily for HF from 52 Chinese hospitals located in 20 provinces between August 2016 and May 2018. The protocol of the China PEACE 5p-HF Study has been published43. In brief, 4,866 patients aged 18 years or older, and hospitalized with a primary diagnosis of new-onset HF or decompensation of chronic HF assessed by local physicians, were enrolled in the study, and 4,363were genotyped using Illumina genotyping arrays. In the current analysis, we used data from 3,972 all-cause HF cases and 1,787 NICM cases that passed genotyping QC procedures. The central ethics committee at Fuwai Hospital and local ethics committees at participating hospitals approved the China PEACE 5p-HF Study. The study was registered at www.clinicaltrials.gov (NCT02878811). The investigation conformed with the principles outlined in the Declaration of Helsinki.
The China Health Evaluation And risk Reduction through nationwide Teamwork (ChinaHEART) project is a government funded public health programme designed for screening of cardiovascular disease risk and for intervention in community based populations throughout China. The design of ChinaHEART project has been described previously44. Briefly, from 20 November 2014 through 31 December 2021, 351 county level regions in all 31 provinces in the mainland of China were selected as study sites to provide diversity in geographical distribution, population structure, and exposure to risk factors and disease patterns. Study site selection also considered population size, population stability, and local capacity to support the project. A total of 4.5 million residents were recruited, and 14,853 were genotyped using Illumina genotyping arrays. In this study, a subset of 11,171 controls who were free from cardiovascular disease (CVD) and HF at baseline and during follow up between 2014 and 2017 were available as control subjects for the China PEACE 5p-HF Study. The central ethics committee at the China National Center for Cardiovascular Diseases approved this study (approval no. 2014-574). All enrolled participants provided written informed consent.
Participating cohorts in the BioBank Japan have been previously described in detail45. Briefly, Biobank Japan is a hospital-based Japanese national biobank project including data from approximately 200,000 patients enrolled between 2003-2007. Participants were recruited at 12 medical institutes throughout Japan.
The UK Biobank recruited participants between 40-69 years of age who were registered with a general practitioner of the UK National Health Service (NHS). Between 2006-2010, a total 503,325 individuals were included. All study participants provided informed consent and the study was approved by the North West Multi-centre Research Ethics Committee. Detailed methods used by the UK Biobank have been described elsewhere46.
Phenotyping
All-cause HF cases included participants with a clinical diagnosis of HF of any aetiology from the China PEACE 5p-HF Study. To avoid any misclassification of cases, we also excluded samples with a diagnosis of hypertrophic cardiomyopathy (HCM) due to the substantial Mendelian inheritance pattern of hypertrophic cardiomyopathy. Among all-cause HF patients, nonischemic cardiomyopathy (NICM) was defined on the basis of left ventricular dysfunction and absence of coronary heart disease (CHD), acute myocardial infarction (AMI) and ischemic cardiomyopathy. Non-HF controls were those who were free from cardiovascular disease (CVD) and HF at baseline and during follow up between 2014 and 2017 from the ChinaHEART project to eliminate the possibility of CVD individuals progressing to HF in controls. This definition strategy resulted in 3,972 all-cause HF cases, 1,787 NICM cases and 11,171 controls.
Genotyping and imputation
Genome-wide genotyping of single-nucleotide polymorphisms (SNPs) in the China PEACE 5p-HF Study and the ChinaHEART project was performed on the Illumina Infinium Global Screening Array chip. Based on sample quality control procedures described in Supplemental Table 15, we excluded duplicate samples (positive controls) and samples with a low call rate (<90%), samples with first-degree relatives (prioritizing the cases and/or samples with higher call-rates from each pair) and samples with discordant ethnicity from Han population. Quality control procedures for genotyped SNPs excluded SNPs with significant departure from Hardy-Weinberg Equilibrium (HWE) in controls (P<1x10−6) and SNPs with a low call rate <97% (Supplemental Table 16). This resulted in 640,842 autosomal SNPs that were available for imputation in 15,143 participants.
Imputation procedures were performed using IMPUTE247 and genotype calls were based on phase3 1000 G Mixed population. Analyses with the imputed data set excluded SNPs with INFO scores <0.8 and with minor allele frequencies (MAF) <0.1% (Supplemental Table 16). This resulted in 6,976,826 autosomal SNPs that were available for a GWAS analysis in 15,143 Han Chinese subjects.
GWAS for HF and NICM in the China PEACE 5p-HF/ChinaHEART
Autosomal SNPs were tested for association with HF and NICM using logistic regression, assuming additive genetic effects. GWAS analyses for HF were also conducted in a sex-specific fashion. GWAS analyses were performed with PLINK v2.0 with adjustment for age, sex (except for sex-stratified GWAS), and the first 3 principal components48. The genome-wide significance threshold was set at P=5.0x10-8. Manhattan and quantile-quantile plots were constructed using ‘qqman’ package (v0.1.8) in R.
Meta-analyses for HF in the China PEACE 5p-HF/ChinaHEART and BioBank Japan
Publicly available summary statistics for HF with 8,678,732 SNPs from the Biobank Japan with 9,413 cases and 203,040 controls were downloaded11. We carried out a fixed-effects meta-analysis in 13,385 cases and 214,211 controls with 5,887,000 SNPs common to the China PEACE 5p-HF/ChinaHEART and the Biobank Japan datasets assuming an additive model, as implemented in METAL49. The genome-wide threshold for significant association was set at P=5.0x10-8. A locus was defined as novel if our lead SNP was >1Mb away or in weak or no (r2≤0.1) linkage disequilibrium (LD) with the lead variants at the 57 previously reported loci for HF7-13. Replication of the 57 known HF loci was considered significant at a Bonferroni-corrected threshold of P=8.8x10-4 (0.05/57).
Sex-stratified Meta-analyses for HF in the China PEACE 5p-HF/ChinaHEART and BioBank Japan
Sex-stratified meta-analyses for all-cause HFassociation was carried out with GWAS result in the China PEACE 5p-HF/ChinaHEART and summary level data in BioBank Japan11 in males (8,419 HF cases and 107,613 controls) and females (4,966 HF cases and 106,598 controls) separately (Supplemental Table 1). Cochran’s Q statistics for heterogeneity P-values between males and females (P-het) were considered significant at the Bonferroni-corrected threshold for testing 5 novel loci (0.05/5=0.01).
Meta-analyses for NICM in the China PEACE 5p-HF/ChinaHEART and the UK BioBank
Publicly available summary statistics for NICM with 7,736,183 SNPs from the UK Biobank with 1,816 cases and 388,326 controls were downloaded8. We carried out a fixed-effects meta-analysis in 3,603 cases and 399,497 controls with 4,566,441 SNPs common to the China PEACE 5p-HF/ChinaHEART and the UK Biobank datasets assuming an additive model, as implemented in METAL49. The genome-wide threshold for significant association was set at P=5.0x10-8. A locus was defined as novel if our lead SNP was >1Mb away or in weak or no (r2≤0.1) linkage disequilibrium (LD) with the lead variants at the 57 previously reported loci for HF7-13.
Association of novel loci with HF risk factors
The lead variants at the newly identified HF loci were evaluated for association with various HF risk factors from previously published studies, including body mass index (BMI)50, blood pressure (systolic blood pressure, diastolic blood pressure, and pulse pressure)51, plasma lipids (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides)52, estimated glomerular filtration rate (eGFR)53, atrial fibrillation (AF)14, coronary artery disease (CAD)54, myocardial infarction (MI)55, and type 2 diabetes (T2D)56. A Bonferroni-corrected P=7.7x10-4 (0.05/65) for testing 5 loci and 13 traits was considered as the threshold for significant associations with HF risk factors.
Association of novel loci with cardiac magnetic resonance imaging (MRI)-derived left ventricular measure
Evaluation of the novel HF loci for association with cardiac magnetic resonance imaging (MRI)-derived left ventricular measure, including left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and stroke volume (SV) were carried out using a previously published study in the UK Biobank15. Associations with P≤ Bonferroni-corrected threshold for testing 5 SNPs and 4 traits (0.05/20=2.5x10-3) were considered significant.
Data-driven Expression-Prioritized Integration for Complex Traits (DEPICT)
Additional gene prioritization analysis and tissue enrichment analysis were carried out by DEPICT (version 1.1)57 using 207 SNPs with false discovery rates (FDRs) < 0.05 (P<1.75x10-6) associated with HF that were identified in the meta-analysis with the China PEACE 5p-HF/ChinaHEARTand BioBank Japan. Both nominal P-values and FDRs were calculated for gene set enrichment and tissue enrichment.
Expression Quantitative Trait Locus (eQTL) and Splice Quantitative Trait Locus (sQTL) analyses
Functional evaluation of SNPs at the 5 novel HF loci and prioritization of candidate causal genes was determined using multi-tissue expression (eQTL) and splice (sQTL) data from the GTEx Project (version 8)16 and other datasets, such as the eQTLgen Consortium58, the Human Protein Atlas (HPA)59 or previously published studies available through the PhenoScanner database17. Consideration was only given to cis eQTLs and cis sQTLs with P<5.0x10−5 that were derived from our lead GWAS variants.
Cell culture and treatment
H9C2 cells obtained from ATCC (Manassas, VA, USA) were cultured in Dulbecco’s modified Eagle’s medium (iCell Bioscience) supplemented with 10% fetal bovine serum (Gibco) and 1% penicillin/streptomycin (Gibco) in a humidified incubator with 5% CO2 at 37℃. When the cell coverage rate reached 70%, trypsin (Gibco) was used to dissociate H9C2. In the cell model of heart failure, phenylephrine (PE) was utilized as agonists according to previous studies60-62. Firstly, H9C2 cells were seeded in 12-well culture plates or confocal dishes at the density of 2×105 cells per well, and then incubated in complete medium for 24 h. Next, serum-free medium was adopted for another 24 h, siRNA transfection could be performed in the meanwhile. Subsequently, PE dissolved in PBS was added to the medium at a final concentration of 100 μM for 48 h. Equal volumes of PBS (vehicle) were administered in control group. After incubation, subsequent experiments were performed, including total RNA extraction for RT-qPCR and cell surface area measured by staining of FITC-labelled Phalloidin. All the cell experiments were repeated three times independently.
SiRNA transfection
The expression levels of SVIL in H9C2 cells were suppressed by siRNA-mediated knockdown targeting SVIL gene. Lipofectamine RNAimax (Invitrogen) was utilized for siSVIL (RiboBio) or non-targeting siRNA (siCtrl) transfection following the manufacturer’s instruments.
In vitro hypertrophy assays
H9C2 cells prepared for immunofluorescence microscopy were seeded in confocal dishes and exposed to hypertrophic agonist PE for 48 h. After activation, cells were fixed in 4% paraformaldehyde and stained with FITC-conjugated phalloidin (Biosharp) for 30 min. DAPI was used for cell nuclei staining. A Leica TCS SP8 STED microscope and Image J software was used to acquire images and measure cell surface area. Fold changes in the average surface area of treated cells were calculated relative to that of untreated ones.
Quantitative real-time PCR
Total RNA was extracted from H9C2 cells using the TRIzol reagent (Invitrogen) as described in the manufacturer’s manual. The obtained RNA was then used for cDNA synthesis with HiScript III RT SuperMix (Vazyme) and subsequently performed qPCR with AceQ qPCR SYBR Green Master Mix (Vazyme). The mRNA expression levels of BNP and ANP were normalized to the housekeeping gene GAPDH. Relative gene expression levels were calculated using ΔΔCt-method. The following primers were used for qRT-PCR: BNP, forward, 5’-GAACAATCCACGATGCAGAAGC-3’ and reverse, 5’-GGGCCTTGGTCCTTTGAGAG-3’; ANP, forward, 5’-GAGGAGAAGATGCCGGTAG-3’ and reverse, 5’- CTAGAGAGGGAGCTAAGTG-3’.
Western blot
For immunoblotting, cells were homogenized in cell lysis buffer (150 mM NaCl, 50 mM HEPES pH 7.4, 1% Triton X-100). Bicinchoninic Acid (BCA) Protein Assay Kit (Thermo Fisher) was used to determine the protein concentration of the samples. Samples were loaded on 10% SDS-PAGE gels and then transferred to polyvinylidene fluoride (PVDF) membranes. The PVDF membrane was incubated in blocking buffer (Beyotime) for 1 h at room temperature. Subsequently, primary antibodies diluted as 1:1000 were applied to the blot overnight at 4℃ with gentle rocking. Antibodies were purchased as follows: supervillin (Santa; sc-53556), caveolin-3 (Proteintech; 28358-1-AP), α-sarcoglycan (Santa; ab189254), GAPDH (ZSGB-bio; TA-08). HRP‑labeled antibody diluted as 1:5000 was used as the secondary antibody and incubated with the membrane for 1 h. Enhanced chemiluminescence (ECL) solution was added on the membrane for its development and photograph.
Cell apoptosis detection
Annexin V-FITC Apoptosis Detection Kit (abcam, ab14085) was used to evaluate the effect of SVIL deficiency and PE treatment on H9C2 cell apoptosis. In brief, H9C2 cells were collected and washed twice with PBS precooled at 4°C. After centrifugation, the supernatant was discarded and the cell pellet was resuspended with 500 μL of 1 × binding buffer. Then, 5 μL annexin V-FITC and 5 μL propidium iodide (PI) were added, mixed gently, and incubated at room temperature in darkness for 15 min. A cell group without staining was set as negative control, and a single dye staining group (stained with only one dye) were set for the voltage of flow cytometry and its compensation, and the apoptosis rate of the cells was detected. Finally, the data were analyzed and plotted with FlowJo V10.
Cell viability assay
The Cell Counting Kit 8 (CCK8) (YEASEN) was applied to measure cell viability. H9C2 cells were seeded into 96-well plates at a density of 2×103 cells/well. After 48 h-treatment, 10 μL CCK8 solution was added into the wells and the cells were incubated for 4 h at 37℃ in the dark. Finally, the absorbance was measured at 450 nm by a microplate reader.
Library construction for RNA-seq and sequencing procedures
Total RNA was isolated using MJzol animal RNA Extraction Kit (MagBeads). Paired-end libraries were synthesized using the TruSeq® RNA Sample Preparation Kit (Illumina, USA) following TruSeq® RNA Sample Preparation Guide. Briefly, the poly-A containing mRNA molecules were purified using poly-T oligo-attached magnetic beads. Following purification, the mRNA was fragmented into small pieces using divalent cations under 94℃ for 8 min. The cleaved RNA fragments were copied into first strand cDNA using reverse transcriptase and random primers, followed by second strand cDNA synthesis using DNA Polymerase I and RNase H. These cDNA fragments then went through an end repair process, the addition of a single ‘A’ base, and then ligation of the adapters. The products were purified and enriched with PCR to create the final cDNA library. Purified libraries were quantified by Qubit® 2.0 Fluorometer (Life Technologies, USA) and validated by Agilent 2100 bioanalyzer (Agilent Technologies, USA) to confirm the insert size and calculate the mole concentration. Cluster was generated by cBot with the library diluted to 10 pM and then sequenced on the Illumina Nova 6000 (Illumina, USA).
Data analysis and identification of differentially expressed genes (DEGs)
Sequencing raw reads were preprocessed by filtering out rRNA reads, sequencing adapters, short-fragment reads and other low-quality reads. We used Hisat2 (version:2.0.4)63 to map the cleaned reads to the rat Rnor_6.0 reference genome with two mismatches. After genome mapping, Stringtie (version:1.3.0)64,65 was used with a reference annotation to generate fragments per kilobase per million reads (FPKM) values for known gene models. Differentially expressed genes (DEGs) were identified using edgeR66. The p-value significance threshold in multiple tests was set by the FDR. The fold-changes were also estimated according to the FPKM in each sample. The DEGs were selected using the following filter criteria: FDR ≤0.05 and fold-change ≥2.
Gene Ontology (GO) enrichment analysis
For functional enrichment analysis, all DEGs were mapped to terms in the GO databases, and then significantly enriched GO terms were defined with P<0.05 and rich factor ≥5 as the threshold. GO term analysis was classified into three subgroups, namely biological process (BP), cellular component (CC) and molecular function (MF).
URLs. Biobank Japan, https://biobankjp.org/english/index.html; The UK Biobank, https://www.ukbiobank.ac.uk/ ; METAL, http://csg.sph.umich.edu/abecasis/metal/index.html;
Genotype-Tissue Expression Project, http://gtexportal.org/; Phenoscanner, http://www.phenoscanner.medschl.cam.ac.uk/phenoscanner; The Human Protein Atlas, https://www.proteinatlas.org; The eQTLgen Consortium, https://www.eqtlgen.org; R statistical software, http://www.R-project.org/.