Genome-wide association study of white-coat effect in hypertensive patients.

Background: White-coat effect (WCE) confounds diagnosis and treatment of hypertension. The prevalence of white-coat hypertension is higher in Europe and Asia compared to other continents suggesting that genetic factors could play a role. Methods: To study genetic variation affecting WCE, we conducted a two-stage genome-wide association study involving 1343 Finnish subjects. For the discovery stage, we used Genetics of Drug Responsiveness in Essential Hypertension (GENRES) cohort (n = 206), providing the mean WCE values from up to four separate office/ambulatory recordings conducted on placebo. Associations with p values <1 × 10-5 were included in the replication step in three independent cohorts: Haemodynamics in Primary and Secondary Hypertension (DYNAMIC) (n = 182), Finn-Home study (n = 773) and Dietary, Lifestyle and Genetic Determinants of Obesity and Metabolic Syndrome (DILGOM) (n = 182). Results: No single nucleotide polymorphisms reached genome-wide significance for association with either systolic or diastolic WCE. However, two loci provided suggestive evidence for association. A known coronary artery disease risk locus rs2292954 in SPG7 associated with systolic WCE (discovery p value = 2.2 × 10-6, replication p value = 0.03 in Finn-Home, meta-analysis p value 2.6 × 10-4), and rs10033652 in RASGEF1B with diastolic WCE (discovery p value = 4.9 × 10-6, replication p value = 0.04 in DILGOM, meta-analysis p value = 5.0 × 10-3). Conclusion: This study provides evidence for two novel candidate genes, SPG7 and RASGEF1B, associating with WCE. Our results need to be validated in even larger studies carried out in other populations.

Genome-wide association study of nocturnal blood pressure dipping in hypertensive patients.

BACKGROUND: Reduced nocturnal fall (non-dipping) of blood pressure (BP) is a predictor of cardiovascular target organ damage. No genome-wide association studies (GWAS) on BP dipping have been previously reported. METHODS: To study genetic variation affecting BP dipping, we conducted a GWAS in Genetics of Drug Responsiveness in Essential Hypertension (GENRES) cohort (n = 204) using the mean night-to-day BP ratio from up to four ambulatory BP recordings conducted on placebo. Associations with P < 1 × 10- 5 were further tested in two independent cohorts: Haemodynamics in Primary and Secondary Hypertension (DYNAMIC) (n = 183) and Dietary, Lifestyle and Genetic determinants of Obesity and Metabolic Syndrome (DILGOM) (n = 180). We also tested the genome-wide significant single nucleotide polymorphism (SNP) for association with left ventricular hypertrophy in GENRES. RESULTS: In GENRES GWAS, rs4905794 near BCL11B achieved genome-wide significance (ß = - 4.8%, P = 9.6 × 10- 9 for systolic and ß = - 4.3%, P = 2.2 × 10- 6 for diastolic night-to-day BP ratio). Seven additional SNPs in five loci had P values < 1 × 10- 5. The association of rs4905794 did not significantly replicate, even though in DYNAMIC the effect was in the same direction (ß = - 0.8%, P = 0.4 for systolic and ß = - 1.6%, P = 0.13 for diastolic night-to-day BP ratio). In GENRES, the associations remained significant even during administration of four different antihypertensive drugs. In separate analysis in GENRES, rs4905794 was associated with echocardiographic left ventricular mass (ß = - 7.6 g/m2, P = 0.02). CONCLUSIONS: rs4905794 near BCL11B showed evidence for association with nocturnal BP dipping. It also associated with left ventricular mass in GENRES. Combined with earlier data, our results provide support to the idea that BCL11B could play a role in cardiovascular pathophysiology.

Endoplasmic reticulum stress increases AT1R mRNA expression via TIA-1-dependent mechanism.

As the formation of ribonucleoprotein complexes is a major mechanism of angiotensin II type 1 receptor (AT1R) regulation, we sought to identify novel AT1R mRNA binding proteins. By affinity purification and mass spectroscopy, we identified TIA-1. This interaction was confirmed by colocalization of AT1R mRNA and TIA-1 by FISH and immunofluorescence microscopy. In immunoprecipitates of endogenous TIA- 1, reverse transcription-PCR amplified AT1R mRNA. TIA-1 has two binding sites within AT1R 3'-UTR. The binding site proximal to the coding region is glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-dependent whereas the distal binding site is not. TIA-1 functions as a part of endoplasmic reticulum (ER) stress response leading to stress granule (SG) formation and translational silencing. We and others have shown that AT1R expression is increased by ER stress-inducing factors. In unstressed cells, TIA-1 binds to AT1R mRNA and decreases AT1R protein expression. Fluorescence microscopy shows that ER stress induced by thapsigargin leads to the transfer of TIA-1 to SGs. In FISH analysis AT1R mRNA remains in the cytoplasm and no longer colocalizes with TIA-1. Thus, release of TIA-1-mediated suppression by ER stress increases AT1R protein expression. In conclusion, AT1R mRNA is regulated by TIA-1 in a ER stress-dependent manner.

Regulation of AT1R expression through HuR by insulin.

Angiotensin II type 1 receptor (AT1R) has a pathophysiological role in hypertension, atherosclerosis and heart failure. Type 2 diabetes is hyperinsulinemic state and a major risk factor for atherosclerosis and hypertension. It is known that hyperinsulinemia upregulates AT1R expression post-transcriptionally by increasing the half-life of AT1R mRNA, but little is known about the mechanism of this effect. In the present study, we first identified AT1R 3'-UTR as a mediator of insulin effect. Using 3'-UTR as a bait, we identified through analysis of insulin-stimulated cell lysates by affinity purification and mass spectrometry HuR as an insulin-regulated AT1R mRNA binding protein. By ribonucleoprotein immunoprecipitation, we found HuR binding to AT1R to be increased by insulin. Overexpression of HuR leads to increased AT1R expression in a 3'-UTR-dependent manner. Both insulin and HuR overexpression stabilize AT1R 3'-UTR and their responsive element within 3'-UTR are located within the same region. Cell fractionation demonstrated that insulin induced HuR translocation from nucleus to cytoplasm increased HuR binding to cytoplasmic AT1R 3'-UTR. Consistent with HuR translocation playing a mechanistic role in HuR effect, a reduction in the cytoplasmic levels of HuR either by silencing of HuR expression or by inhibition of HuR translocation into cytoplasm attenuated insulin response. These results show that HuR translocation to cytoplasm is enhanced by insulin leading to AT1R upregulation through HuR-mediated stabilization of AT1R mRNA.

L-type calcium channel blocker increases VEGF concentrations in retinal cells and human serum.

OBJECTIVE: Vascular endothelial growth factor (VEGF) plays a key role in diabetic retinopathy (DR). Previously, we have reported an association between mutations in a gene coding for the L-type calcium channel subunit, VEGF and DR. L-type calcium channel blockers (LTCCBs) have been widely used as antihypertensive medication (AHM), but their association with VEGF and DR is still unclear. Therefore, we explored the effect of LTCCBs compared to other AHMs on VEGF concentrations in retinal cells and human serum. Furthermore, we evaluated the association between the use of LTCCBs and the risk of severe diabetic eye disease (SDED). RESEARCH DESIGN AND METHODS: Müller cells (MIO-M1) were cultured as per recommended protocol and treated with LTCCBs and other AHMs. VEGF secreted from cells were collected at 24 hours intervals. In an interventional study, 39 individuals received LTCCBs or other AHM for four weeks with a four-week wash-out placebo period between treatments. VEGF was measured during the medication and placebo periods. Finally, we evaluated the risk of SDED associated with LTCCB usage in 192 individuals from the FinnDiane Study in an observational setting. RESULTS: In the cell cultures, the medium VEGF concentration increased time-dependently after amlodipine (P<0.01) treatment, but not after losartan (P>0.01), or lisinopril (P>0.01). Amlodipine, but no other AHM, increased the serum VEGF concentration (P<0.05) during the interventional clinical study. The usage of LTCCB was not associated with the risk of SDED in the observational study. CONCLUSIONS: LTCCB increases VEGF concentrations in retinal cells and human serum. However, the usage of LTCCBs does not appear to be associated with SDED in adults with type 1 diabetes.

Pharmacoepigenetics of hypertension: genome-wide methylation analysis of responsiveness to four classes of antihypertensive drugs using a double-blind crossover study design.

Essential hypertension remains the leading risk factor of global disease burden, but its treatment goals are often not met. We investigated whether DNA methylation is associated with antihypertensive responses to a diuretic, a beta-blocker, a calcium channel blocker or an angiotensin receptor antagonist. In addition, since we previously showed an SNP at the transcription start site (TSS) of the catecholamine biosynthesis-related ACY3 gene to associate with blood pressure (BP) response to beta-blockers, we specifically analysed the association of methylation sites close to the ACY3 TSS with BP responses to beta-blockers. We conducted an epigenome-wide association study between leukocyte DNA methylation and BP responses to antihypertensive monotherapies in two hypertensive Finnish cohorts: the GENRES (https://clinicaltrials.gov/ct2/show/NCT03276598; amlodipine 5 mg, bisoprolol 5 mg, hydrochlorothiazide 25 mg, or losartan 50 mg daily) and the LIFE-Fin studies (https://clinicaltrials.gov/ct2/show/NCT00338260; atenolol 50 mg or losartan 50 mg daily). The monotherapy groups consisted of approximately 200 individuals each. We identified 64 methylation sites to suggestively associate (P < 1E-5) with either systolic or diastolic BP responses to a particular study drug in GENRES. These associations did not replicate in LIFE-Fin . Three methylation sites close to the ACY3 TSS were associated with systolic BP responses to bisoprolol in GENRES but not genome-wide significantly (P < 0.05). No robust associations between DNA methylation and BP responses to four different antihypertensive drugs were identified. However, the findings on the methylation sites close to the ACY3 TSS may support the role of ACY3 genetic and epigenetic variation in BP response to bisoprolol.

Chromosomal Region 11p14.1 is Associated with Pharmacokinetics and Pharmacodynamics of Bisoprolol.

Purpose: Bisoprolol is a widely used beta-blocker in patients with cardiovascular diseases. As with other beta-blockers, there is variability in response to bisoprolol, but the underlying reasons for this have not been clearly elucidated. Our aim was to investigate genetic factors that affect bisoprolol pharmacokinetics (PK) and pharmacodynamics (PD), and potentially the clinical outcomes. Patients and Methods: Patients with non-ST elevation acute coronary syndrome were recruited prospectively on admission to hospital and followed up for up to 2 years. Patients from this cohort who were on treatment with bisoprolol, at any dose, had bisoprolol adherence data and a plasma sample, one month after discharge from index hospitalisation were included in the study. Individual bisoprolol clearance values were estimated using population pharmacokinetic modeling. Genome-wide association analysis after genotyping was undertaken using an Illumina HumanOmniExpressExome-8 v1.0 BeadChip array, while CYP2D6 copy number variations were determined by PCR techniques and phenotypes for CYP2D6 and CYP3A were inferred from the genotype. GWAS significant SNPs were analysed for heart rate response to bisoprolol in an independent cohort of hypertensive subjects. Results: Six hundred twenty-two patients on bisoprolol underwent both PK and genome wide analysis. The mean (IQR) of the estimated clearance in this population was 13.6 (10.0-18.0) L/h. Bisoprolol clearance was associated with rs11029955 (p=7.17×10-9) mapped to the region of coiled-coil domain containing 34 region (CCDC34) on chromosome 11, and with rs116702638 (p=2.54×10-8). Each copy of the minor allele of rs11029955 was associated with 2.2 L/h increase in clearance. In an independent cohort of hypertensive subjects, rs11029955 was associated with 24-hour heart rate response to 4-week treatment with bisoprolol (p= 9.3×10-5), but not with rs116702638. Conclusion: A novel locus on the chromosomal region 11p14.1 was associated with bisoprolol clearance in a real-world cohort of patients and was validated in independent cohort with a pharmacodynamic association.

Posttranscriptional regulation of angiotensin II type 1 receptor expression by glyceraldehyde 3-phosphate dehydrogenase.

Regulation of angiotensin II type 1 receptor (AT1R) has a pathophysiological role in hypertension, atherosclerosis and heart failure. We started from an observation that the 3'-untranslated region (3'-UTR) of AT1R mRNA suppressed AT1R translation. Using affinity purification for the separation of 3'-UTR-binding proteins and mass spectrometry for their identification, we describe glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as an AT1R 3'-UTR-binding protein. RNA electrophoretic mobility shift analysis with purified GAPDH further demonstrated a direct interaction with the 3'-UTR while GAPDH immunoprecipitation confirmed this interaction with endogenous AT1R mRNA. GAPDH-binding site was mapped to 1-100 of 3'-UTR. GAPDH-bound target mRNAs were identified by expression array hybridization. Analysis of secondary structures shared among GAPDH targets led to the identification of a RNA motif rich in adenines and uracils. Silencing of GAPDH increased the expression of both endogenous and transfected AT1R. Similarly, a decrease in GAPDH expression by H(2)O(2) led to an increased level of AT1R expression. Consistent with GAPDH having a central role in H(2)O(2)-mediated AT1R regulation, both the deletion of GAPDH-binding site and GAPDH overexpression attenuated the effect of H(2)O(2) on AT1R mRNA. Taken together, GAPDH is a translational suppressor of AT1R and mediates the effect of H(2)O(2) on AT1R mRNA.

Adverse Cardiovascular Outcomes and Antihypertensive Treatment: A Genome-Wide Interaction Meta-Analysis in the International Consortium for Antihypertensive Pharmacogenomics Studies.

We sought to identify genome-wide variants influencing antihypertensive drug response and adverse cardiovascular outcomes, utilizing data from four randomized controlled trials in the International Consortium for Antihypertensive Pharmacogenomics Studies (ICAPS). Genome-wide antihypertensive drug-single nucleotide polymorphism (SNP) interaction tests for four drug classes (ß-blockers, n = 9,195; calcium channel blockers (CCBs), n = 10,511; thiazide/thiazide-like diuretics, n = 3,516; ACE-inhibitors/ARBs, n = 2,559) and cardiovascular outcomes (incident myocardial infarction, stroke, or death) were analyzed among patients with hypertension of European ancestry. Top SNPs from the meta-analyses were tested for replication of cardiovascular outcomes in an independent Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) study (n = 21,267), blood pressure (BP) response in independent ICAPS studies (n = 1,552), and ethnic validation in African Americans from the Genetics of Hypertension Associated Treatment study (GenHAT; n = 5,115). One signal reached genome-wide significance in the ß-blocker-SNP interaction analysis (rs139945292, Interaction P = 1.56 × 10-8 ). rs139945292 was validated through BP response to ß-blockers, with the T-allele associated with less BP reduction (systolic BP response P = 6 × 10-4 , Beta = 3.09, diastolic BP response P = 5 × 10-3 , Beta = 1.53). The T-allele was also associated with increased adverse cardiovascular risk within the ß-blocker treated patients' subgroup (P = 2.35 × 10-4 , odds ratio = 1.57, 95% confidence interval = 1.23-1.99). The locus showed nominal replication in CHARGE, and consistent directional trends in ß-blocker treated African Americans. rs139945292 is an expression quantitative trait locus for the 50 kb upstream gene NTM (neurotrimin). No SNPs attained genome-wide significance for any other drugs classes. Top SNPs were located near CALB1 (CCB), FLJ367777 (ACE-inhibitor), and CES5AP1 (thiazide). The NTM region is associated with increased risk for adverse cardiovascular outcomes and less BP reduction in ß-blocker treated patients. Further investigation into this region is warranted.

p100 increases AT1R expression through interaction with AT1R 3'-UTR.

p100 protein (SND1, Tudor-SN) is a multifunctional protein that functions as a co-activator for several transcription factors, has a role in mRNA processing and participates in RNAi-induced silencing complex (RISC) with yet unknown function. In this study we identified a novel function for p100 as a regulator of angiotensin II type 1 receptor (AT1R) expression. The binding of p100 to AT1R 3'-untranslated region (3'-UTR) via staphylococcal nuclease-like (SN-like) domains increased receptor expression by decreasing the rate of mRNA decay and enhancing its translation. Overexpression of p100 increased AT1R expression, whereas decrease in p100 binding to 3'-UTR either by p100 silencing or by the deletion of p100 binding site downregulated receptor expression. The effect of p100 through AT1R 3'-UTR was independent of Argonaute2 (Ago2), a known p100 partner, and was thus RISC-independent. Nucleotides 118 to 120 of the AT1R 3'-UTR were found to be critical for the binding of p100 to 3'-UTR. In summary, p100 is a multifunctional regulator of gene expression that regulates transcription, mRNA maturation, and as described in this article, also mRNA stability and translation.

Effect of four classes of antihypertensive drugs on cardiac repolarization heterogeneity: A double-blind rotational study.

BACKGROUND: T-wave area dispersion (TW-Ad) is a novel electrocardiographic (ECG) repolarization marker associated with sudden cardiac death. However, limited data is available on the clinical correlates of TW-Ad. In addition, there are no previous studies on cardiovascular drug effects on TW-Ad. In this study, we examined the relation between TW-Ad and left ventricular mass. We also studied the effects of four commonly used antihypertensive drugs on TW-Ad. METHODS: A total of 242 moderately hypertensive males (age, 51±6 years; office systolic/diastolic blood pressure during placebo, 153±14/100±8 mmHg), participating in the GENRES study, were included. Left ventricular mass index was determined by transthoracic echocardiography. Antihypertensive four-week monotherapies (a diuretic, a beta-blocker, a calcium channel blocker, and an angiotensin receptor antagonist) were administered in a randomized rotational fashion. Four-week placebo periods preceded all monotherapies. The average value of measurements (over 1700 ECGs in total) from all available placebo periods served as a reference to which measurements during each drug period were compared. RESULTS: Lower, i.e. risk-associated TW-Ad values correlated with a higher left ventricular mass index (r = -0.14, p = 0.03). Bisoprolol, a beta-blocker, elicited a positive change in TW-Ad (p = 1.9×10-5), but the three other drugs had no significant effect on TW-Ad. CONCLUSIONS: Our results show that TW-Ad is correlated with left ventricular mass and can be modified favorably by the use of bisoprolol, although demonstration of any effects on clinical endpoints requires long-term prospective studies. Altogether, our results suggest that TW-Ad is an ECG repolarization measure of left ventricular arrhythmogenic substrate.

Human essential hypertension: no significant association of polygenic risk scores with antihypertensive drug responses.

Polygenic risk scores (PRSs) for essential hypertension, calculated from > 900 genomic loci, were recently found to explain a significant fraction of hypertension heritability and complications. To investigate whether variation of hypertension PRS also captures variation of antihypertensive drug responsiveness, we calculated two different PRSs for both systolic and diastolic blood pressure: one based on the top 793 independent hypertension-associated single nucleotide polymorphisms and another based on over 1 million genome-wide variants. Using our pharmacogenomic GENRES study comprising four different antihypertensive monotherapies (n ~ 200 for all drugs), we identified a weak, but (after Bonferroni correction) statistically nonsignificant association of higher genome-wide PRSs with weaker response to a diuretic. In addition, we noticed a correlation between high genome-wide PRS and electrocardiographic left ventricular hypertrophy. Finally, using data of the Finnish arm of the LIFE study (n = 346), we found that PRSs for systolic blood pressure were slightly higher in patients with drug-resistant hypertension than in those with drug-controlled hypertension (p = 0.03, not significant after Bonferroni correction). In conclusion, our results indicate that patients with elevated hypertension PRSs may be predisposed to difficult-to-control hypertension and complications thereof. No general association between a high PRS and less efficient drug responsiveness was noticed.

Genome-Wide Meta-Analysis of Blood Pressure Response to ß1-Blockers: Results From ICAPS (International Consortium of Antihypertensive Pharmacogenomics Studies).

BackgroundThere exists a wide interindividual variability in blood pressure (BP) response to ß1-blockers. To identify the genetic determinants of this variability, we performed a pharmacogenomic genome-wide meta-analysis of genetic variants influencing ß1-blocker BP response.Methods and ResultsGenome-wide association analysis for systolic BP and diastolic BP response to ß1-blockers from 5 randomized clinical trials consisting of 1254 patients with hypertension of European ancestry were combined in meta-analysis and single nucleotide polymorphisms (SNPs) with P<10-4 were tested for replication in 2 independent randomized clinical trials of ß1-blocker-treated patients of European ancestry (n=1552). Regions harboring the replicated SNPs were validated in a ß1-blocker-treated black cohort from 2 randomized clinical trials (n=315). A missense SNP rs28404156 in BST1 was associated with systolic BP response to ß1-blockers in the discovery meta-analysis (P=9.33×10-5, ß=-3.21 mm Hg) and replicated at Bonferroni significance (P=1.85×10-4, ß=-4.86 mm Hg) in the replication meta-analysis with combined meta-analysis approaching genome-wide significance (P=2.18×10-7). This SNP in BST1 is in linkage disequilibrium with several SNPs with putative regulatory functions in nearby genes, including CD38, FBXL5, and FGFBP1, all of which have been implicated in BP regulation. SNPs in this genetic region were also associated with BP response in the black cohort.ConclusionsData from randomized clinical trials of 8 European ancestry and 2 black cohorts support the assumption that BST1 containing locus on chromosome 4 is associated with ß1-blocker BP response. Given the previous associations of this region with BP, this is a strong candidate region for future functional studies and potential use in precision medicine approaches for BP management and risk prediction.

Effect of hydrochlorothiazide on serum uric acid concentration: a genome-wide association study.

AIM: To recognize genetic associations of hydrochlorothiazide-induced change in serum uric acid (SUA) concentration. PATIENTS & METHODS: We conducted a genome-wide association study on hydrochlorothiazide-induced change in SUA in 214 Finnish men from the GENRES study. Replication analyses were performed in 465 Finns from the LIFE study. RESULTS: In GENRES, we identified 31 loci associated with hydrochlorothiazide-induced change in SUA at p < 5 × 10-5. rs1002976 near VEGFC associated with the change in GENRES and in LIFE. rs950569 near BRINP3 associated with the change in SUA in GENRES and LIFE. The analysis of previously reported SNPs and candidate genes provided some proof for PADI4 and ABCC4. CONCLUSION: We report genetic markers that may predict the increase in SUA concentration during thiazide treatment.

Effects of four different antihypertensive drugs on plasma metabolomic profiles in patients with essential hypertension.

OBJECTIVE: In order to search for metabolic biomarkers of antihypertensive drug responsiveness, we measured >600 biochemicals in plasma samples of subjects participating in the GENRES Study. Hypertensive men received in a double-blind rotational fashion amlodipine, bisoprolol, hydrochlorothiazide and losartan, each as a monotherapy for one month, with intervening one-month placebo cycles. METHODS: Metabolomic analysis was carried out using ultra high performance liquid chromatography-tandem mass spectrometry. Full metabolomic signatures (the drug cycles and the mean of the 3 placebo cycles) became available in 38 to 42 patients for each drug. Blood pressure was monitored by 24-h recordings. RESULTS: Amlodipine (P values down to 0.002), bisoprolol (P values down to 2 x 10-5) and losartan (P values down to 2 x 10-4) consistently decreased the circulating levels of long-chain acylcarnitines. Bisoprolol tended to decrease (P values down to 0.002) the levels of several medium- and long-chain fatty acids. Hydrochlorothiazide administration was associated with an increase of plasma uric acid level (P = 5 x 10-4) and urea cycle metabolites. Decreases of both systolic (P = 0.06) and diastolic (P = 0.04) blood pressure after amlodipine administration tended to associate with a decrease of plasma hexadecanedioate, a dicarboxylic fatty acid recently linked to blood pressure regulation. CONCLUSIONS: Although this systematic metabolomics study failed to identify circulating metabolites convincingly predicting favorable antihypertensive response to four different drug classes, it provided accumulating evidence linking fatty acid metabolism to human hypertension.

Replicated evidence for aminoacylase 3 and nephrin gene variations to predict antihypertensive drug responses.

AIM: To replicate the genome-wide associations of the antihypertensive effects of bisoprolol and losartan in GENRES, using the Finnish patients of LIFE study. PATIENTS & METHODS: We analyzed association of four SNPs with atenolol and three SNPs with losartan response in 927 Finnish LIFE patients (467 for atenolol and 460 for losartan). RESULTS: rs2514036, a variation at a transcription start site of ACY3, was associated with blood pressure response to atenolol in men in LIFE. Response to bisoprolol was correlated to baseline plasma levels of N-acetylphenylalanine and phenylalanine (ACY3 substrate and end product, respectively) in GENRES study. NPHS1 variation rs3814995 was associated with losartan effect in LIFE. CONCLUSION: We provide support for two pharmacogenomic markers for beta-blockers and angiotensin receptor antagonists.

Genome-Wide and Gene-Based Meta-Analyses Identify Novel Loci Influencing Blood Pressure Response to Hydrochlorothiazide.

This study aimed to identify novel loci influencing the antihypertensive response to hydrochlorothiazide monotherapy. A genome-wide meta-analysis of blood pressure (BP) response to hydrochlorothiazide was performed in 1739 white hypertensives from 6 clinical trials within the International Consortium for Antihypertensive Pharmacogenomics Studies, making it the largest study to date of its kind. No signals reached genome-wide significance (P<5×10-8), and the suggestive regions (P<10-5) were cross-validated in 2 black cohorts treated with hydrochlorothiazide. In addition, a gene-based analysis was performed on candidate genes with previous evidence of involvement in diuretic response, in BP regulation, or in hypertension susceptibility. Using the genome-wide meta-analysis approach, with validation in blacks, we identified 2 suggestive regulatory regions linked to gap junction protein α1 gene (GJA1) and forkhead box A1 gene (FOXA1), relevant for cardiovascular and kidney function. With the gene-based approach, we identified hydroxy-delta-5-steroid dehydrogenase, 3 ß- and steroid δ-isomerase 1 gene (HSD3B1) as significantly associated with BP response (P<2.28×10-4 ). HSD3B1 encodes the 3ß-hydroxysteroid dehydrogenase enzyme and plays a crucial role in the biosynthesis of aldosterone and endogenous ouabain. By amassing all of the available pharmacogenomic studies of BP response to hydrochlorothiazide, and using 2 different analytic approaches, we identified 3 novel loci influencing BP response to hydrochlorothiazide. The gene-based analysis, never before applied to pharmacogenomics of antihypertensive drugs to our knowledge, provided a powerful strategy to identify a locus of interest, which was not identified in the genome-wide meta-analysis because of high allelic heterogeneity. These data pave the way for future investigations on new pathways and drug targets to enhance the current understanding of personalized antihypertensive treatment.

Pharmacogenomics of hypertension: a genome­wide, placebo­controlled cross­over study, using four classes of antihypertensive drugs.

BACKGROUND: Identification of genetic markers of antihypertensive drug responses could assist in individualization of hypertension treatment. METHODS AND RESULTS: We conducted a genome-wide association study to identify gene loci influencing the responsiveness of 228 male patients to 4 classes of antihypertensive drugs. The Genetics of Drug Responsiveness in Essential Hypertension (GENRES) study is a double-blind, placebo-controlled cross-over study where each subject received amlodipine, bisoprolol,hydrochlorothiazide, and losartan, each as a monotherapy, in a randomized order. Replication analyses were performed in 4 studies with patients of European ancestry (PEAR Study, N=386; GERA I and II Studies, N=196 and N=198; SOPHIA Study, N=372). We identified 3 single-nucleotide polymorphisms within the ACY3 gene that showed associations with bisoprolol response reaching genome-wide significance (P<5x10(-8))however, this could not be replicated in the PEAR Study using atenolol. In addition, 39 single-nucleotide polymorphisms showed P values of 10(-5) to 10(-7). The 20 top-associated single-nucleotide polymorphisms were different for each antihypertensive drug. None of these top single-nucleotide polymorphisms co-localized with the panel of >40 genes identified in genome-wide association studies of hypertension. Replication analyses of GENRES results provided suggestive evidence for a missense variant (rs3814995) in the NPHS1 (nephrin) gene influencing losartan response, and for 2 variants influencing hydrochlorothiazide response, located within or close to the ALDH1A3 (rs3825926) and CLIC5 (rs321329) genes. CONCLUSIONS: These data provide some evidence for a link between biology of the glomerular protein nephrin and antihypertensive action of angiotensin receptor antagonists and encourage additional studies on aldehyde dehydrogenase­mediated reactions in antihypertensive drug action.

PTPRD gene associated with blood pressure response to atenolol and resistant hypertension.

OBJECTIVE: The aim of this study is to identify single-nucleotide polymorphisms (SNPs) influencing blood pressure (BP) response to the ß-blocker atenolol. METHODS: Genome-wide association analysis of BP response to atenolol monotherapy was performed in 233 white participants with uncomplicated hypertension in the pharmacogenomic evaluation of antihypertensive responses study. Forty-two polymorphisms with P less than 10 for association with either diastolic or systolic response to atenolol monotherapy were validated in four independent groups of hypertensive individuals (total n = 2114). RESULTS: In whites, two polymorphisms near the gene PTPRD (rs12346562 and rs1104514) were associated with DBP response to atenolol (P = 3.2 × 10 and P = 5.9 × 10, respectively) with directionally opposite association for response to hydrochlorothiazide in another group of 228 whites (P = 0.0018 and P = 0.00012). A different polymorphism (rs10739150) near PTPRD was associated with response to atenolol in 150 black hypertensive individuals (P = 8.25 × 10). rs12346562 had a similar trend in association with response to bisoprolol (a different ß-blocker) in 207 Finnish men in the genetics of drug responsiveness in essential hypertension study. In addition, an intronic single-nucleotide polymorphism (rs4742610) in the PTPRD gene was associated with resistant hypertension in whites and Hispanics in the international verapamil SR trandolapril study (meta-analysis P = 3.2 × 10). CONCLUSION: PTPRD was identified as a novel locus potentially associated with BP response to atenolol and resistant hypertension in multiple ethnic groups.

TET2 and CSMD1 genes affect SBP response to hydrochlorothiazide in never-treated essential hypertensives.

BACKGROUND: Thiazide diuretics have been recommended as a first-line antihypertensive treatment, although the choice of 'the right drug in the individual essential hypertensive patient' remains still empirical. Essential hypertension is a complex, polygenic disease derived from the interaction of patient's genetic background with the environment. Pharmacogenomics could be a useful tool to pinpoint gene variants involved in antihypertensive drug response, thus optimizing therapeutic advantages and minimizing side effects. METHODS AND RESULTS: We looked for variants associated with blood pressure response to hydrochlorothiazide over an 8-week follow-up by means of a genome-wide association analysis in two Italian cohorts of never-treated essential hypertensive patients: 343 samples from Sardinia and 142 from Milan. TET2 and CSMD1 as plausible candidate genes to affect SBP response to hydrochlorothiazide were identified. The specificity of our findings for hydrochlorothiazide was confirmed in an independent cohort of essential hypertensive patients treated with losartan. Our best findings were also tested for replication in four independent hypertensive samples of European Ancestry, such as GENetics of drug RESponsiveness in essential hypertension, Genetic Epidemiology of Responses to Antihypertensives, NORdic DILtiazem intervention, Pharmacogenomics Evaluation of Antihypertensive Responses, and Campania Salute Network-StayOnDiur. We validated a polymorphism in CSMD1 and UGGT2. CONCLUSION: This exploratory study reports two plausible loci associated with SBP response to hydrochlorothiazide: TET2, an aldosterone-responsive mediator of αENaC gene transcription; and CSMD1, previously described as associated with hypertension in a case-control study.