Publications by authors named "Stephen T Turner"

274 Publications

Hypertensive Diseases in Pregnancy and Kidney Function Later in Life: The Genetic Epidemiology Network of Arteriopathy (GENOA) Study.

Mayo Clin Proc 2021 Sep 23. Epub 2021 Sep 23.

University of Mississippi Medical Center, Department of Medicine, Division of Cardiology, Jackson, MS. Electronic address:

Objective: To evaluate the relationship between hypertensive diseases in pregnancy and kidney function later in life.

Methods: We evaluated measured glomerular filtration rate (mGFR) using iothalamate urinary clearance in 725 women of the Genetic Epidemiology Network of Arteriopathy (GENOA) study. Women were classified by self-report as nulliparous (n=62), a history of normotensive pregnancies (n=544), a history of hypertensive pregnancies (n=102), or a history of pre-eclampsia (n=17). We compared adjusted associations among these four groups with mGFR using generalized estimating equations to account for familial clustering. Chronic kidney disease (CKD) was defined as mGFR of less than 60 mL/min per 1.73 m or urinary albumin-creatinine ratio (UACR) greater than or equal to 30 mg/g.

Results: Among women with kidney function measurements (mean age, 59±9 years, 52.9% African American), those with a history of hypertensive pregnancy had lower mGFR (-4.66 ml/min per 1.73 m; 95% CI, -9.12 to -0.20) compared with women with a history of normotensive pregnancies. Compared with women with a history of normotensive pregnancies, women with a history of hypertensive pregnancy also had higher odds of mGFR less than 60 ml/min per 1.73 m (odds ratio, 2.09; 95% CI, 1.21 to 3.60). Additionally, women with a history of hypertensive pregnancy had greater odds for chronic kidney disease (odds ratio, 4.89; 95% CI, 1.55 to 15.44), after adjusting for age, race, education, smoking history, hypertension, body mass index, and diabetes.

Conclusion: A history of hypertension in pregnancy is an important prognostic risk factor for kidney disease. To our knowledge, this is the first and largest investigation showing the association between hypertensive diseases in pregnancy and subsequent kidney disease using mGFR in a large biracial cohort.
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http://dx.doi.org/10.1016/j.mayocp.2021.07.018DOI Listing
September 2021

Cerebral small vessel disease genomics and its implications across the lifespan.

Nat Commun 2020 12 8;11(1):6285. Epub 2020 Dec 8.

University of Alabama at Birmingham School of Medicine, Birmingham, AL, 35233, USA.

White matter hyperintensities (WMH) are the most common brain-imaging feature of cerebral small vessel disease (SVD), hypertension being the main known risk factor. Here, we identify 27 genome-wide loci for WMH-volume in a cohort of 50,970 older individuals, accounting for modification/confounding by hypertension. Aggregated WMH risk variants were associated with altered white matter integrity (p = 2.5×10-7) in brain images from 1,738 young healthy adults, providing insight into the lifetime impact of SVD genetic risk. Mendelian randomization suggested causal association of increasing WMH-volume with stroke, Alzheimer-type dementia, and of increasing blood pressure (BP) with larger WMH-volume, notably also in persons without clinical hypertension. Transcriptome-wide colocalization analyses showed association of WMH-volume with expression of 39 genes, of which four encode known drug targets. Finally, we provide insight into BP-independent biological pathways underlying SVD and suggest potential for genetic stratification of high-risk individuals and for genetically-informed prioritization of drug targets for prevention trials.
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http://dx.doi.org/10.1038/s41467-020-19111-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7722866PMC
December 2020

Discovery of rare variants associated with blood pressure regulation through meta-analysis of 1.3 million individuals.

Nat Genet 2020 12 23;52(12):1314-1332. Epub 2020 Nov 23.

Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Herlev, Denmark.

Genetic studies of blood pressure (BP) to date have mainly analyzed common variants (minor allele frequency > 0.05). In a meta-analysis of up to ~1.3 million participants, we discovered 106 new BP-associated genomic regions and 87 rare (minor allele frequency ≤ 0.01) variant BP associations (P < 5 × 10), of which 32 were in new BP-associated loci and 55 were independent BP-associated single-nucleotide variants within known BP-associated regions. Average effects of rare variants (44% coding) were ~8 times larger than common variant effects and indicate potential candidate causal genes at new and known loci (for example, GATA5 and PLCB3). BP-associated variants (including rare and common) were enriched in regions of active chromatin in fetal tissues, potentially linking fetal development with BP regulation in later life. Multivariable Mendelian randomization suggested possible inverse effects of elevated systolic and diastolic BP on large artery stroke. Our study demonstrates the utility of rare-variant analyses for identifying candidate genes and the results highlight potential therapeutic targets.
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http://dx.doi.org/10.1038/s41588-020-00713-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7610439PMC
December 2020

Genome-Wide Association Meta-Analysis of Individuals of European Ancestry Identifies Suggestive Loci for Sodium Intake, Potassium Intake, and Their Ratio Measured from 24-Hour or Half-Day Urine Samples.

J Nutr 2020 10;150(10):2635-2645

Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA.

Background: Excess sodium intake and insufficient potassium intake are risk factors for hypertension, but there is limited knowledge regarding genetic factors that influence intake. Twenty-hour or half-day urine samples provide robust estimates of sodium and potassium intake, outperforming other measures such as spot urine samples and dietary self-reporting.

Objective: The aim of this study was to investigate genomic regions associated with sodium intake, potassium intake, and sodium-to-potassium ratio measured from 24-h or half-day urine samples.

Methods: Using samples of European ancestry (mean age: 54.2 y; 52.3% women), we conducted a meta-analysis of genome-wide association studies in 4 cohorts with 24-h or half-day urine samples (n = 6,519), followed by gene-based analysis. Suggestive loci (P < 10-6) were examined in additional European (n = 844), African (n = 1,246), and Asian (n = 2,475) ancestry samples.

Results: We found suggestive loci (P < 10-6) for all 3 traits, including 7 for 24-h sodium excretion, 4 for 24-h potassium excretion, and 4 for sodium-to-potassium ratio. The most significant locus was rs77958157 near cocaine- and amphetamine-regulated transcript prepropeptide (CARTPT) , a gene involved in eating behavior and appetite regulation (P = 2.3 × 10-8 with sodium-to-potassium ratio). Two suggestive loci were replicated in additional samples: for sodium excretion, rs12094702 near zinc finger SWIM-type containing 5 (ZSWIM5) was replicated in the Asian ancestry sample reaching Bonferroni-corrected significance (P = 0.007), and for potassium excretion rs34473523 near sodium leak channel (NALCN) was associated at a nominal P value with potassium excretion both in European (P = 0.043) and African (P = 0.043) ancestry cohorts. Gene-based tests identified 1 significant gene for sodium excretion, CDC42 small effector 1 (CDC42SE1), which is associated with blood pressure regulation.

Conclusions: We identified multiple suggestive loci for sodium and potassium intake near genes associated with eating behavior, nervous system development and function, and blood pressure regulation in individuals of European ancestry. Further research is needed to replicate these findings and to provide insight into the underlying genetic mechanisms by which these genomic regions influence sodium and potassium intake.
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http://dx.doi.org/10.1093/jn/nxaa241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549298PMC
October 2020

Sorting nexin 1 loss results in increased oxidative stress and hypertension.

FASEB J 2020 06 15;34(6):7941-7957. Epub 2020 Apr 15.

Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.

Acute renal depletion of sorting nexin 1 (SNX1) in mice results in blunted natriuretic response and hypertension due to impaired dopamine D receptor (D R) activity. We elucidated the molecular mechanisms for these phenotypes in Snx1 mice. These mice had increased renal expressions of angiotensin II type 1 receptor (AT R), NADPH oxidase (NOX) subunits, D R, and NaCl cotransporter. Basal reactive oxygen species (ROS), NOX activity, and blood pressure (BP) were also higher in Snx1 mice, which were normalized by apocynin, a drug that prevents NOX assembly. Renal proximal tubule (RPT) cells from hypertensive (HT) Euro-American males had deficient SNX1 activity, impaired D R endocytosis, and increased ROS compared with cells from normotensive (NT) Euro-American males. siRNA-mediated depletion of SNX1 in RPT cells from NT subjects led to a blunting of D R agonist-induced increase in cAMP production and decrease in Na transport, effects that were normalized by over-expression of SNX1. Among HT African-Americans, three of the 12 single nucleotide polymorphisms interrogated for the SNX1 gene were associated with a decrease in systolic BP in response to hydrochlorothiazide (HCTZ). The results illustrate a new paradigm for the development of hypertension and imply that the trafficking protein SNX1 may be a crucial determinant for hypertension and response to antihypertensive therapy.
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http://dx.doi.org/10.1096/fj.201902448RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7643053PMC
June 2020

Genetic Architecture of Gene Expression in European and African Americans: An eQTL Mapping Study in GENOA.

Am J Hum Genet 2020 04 26;106(4):496-512. Epub 2020 Mar 26.

Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address:

Most existing expression quantitative trait locus (eQTL) mapping studies have been focused on individuals of European ancestry and are underrepresented in other populations including populations with African ancestry. Lack of large-scale well-powered eQTL mapping studies in populations with African ancestry can both impede the dissemination of eQTL mapping results that would otherwise benefit individuals with African ancestry and hinder the comparable analysis for understanding how gene regulation is shaped through evolution. We fill this critical knowledge gap by performing a large-scale in-depth eQTL mapping study on 1,032 African Americans (AA) and 801 European Americans (EA) in the GENOA cohort. We identified a total of 354,931 eSNPs in AA and 371,309 eSNPs in EA, with 112,316 eSNPs overlapped between the two. We found that eQTL harboring genes (eGenes) are enriched in metabolic pathways and tend to have higher SNP heritability compared to non-eGenes. We found that eGenes that are common in the two populations tend to be less conserved than eGenes that are unique to one population, which are less conserved than non-eGenes. Through conditional analysis, we found that eGenes in AA tend to harbor more independent eQTLs than eGenes in EA, suggesting potentially diverse genetic architecture underlying expression variation in the two populations. Finally, the large sample sizes in GENOA allow us to construct accurate expression prediction models in both AA and EA, facilitating powerful transcriptome-wide association studies. Overall, our results represent an important step toward revealing the genetic architecture underlying expression variation in African Americans.
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http://dx.doi.org/10.1016/j.ajhg.2020.03.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7118581PMC
April 2020

Genome-wide Association Study of 24-Hour Urinary Excretion of Calcium, Magnesium, and Uric Acid.

Mayo Clin Proc Innov Qual Outcomes 2019 Dec 22;3(4):448-460. Epub 2019 Nov 22.

Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, MN.

Objectives: The urinary excretion of organic and inorganic substances and their concentrations have attracted extensive attention for their role in the pathogenesis of urinary stone disease. The urinary excretion of specific factors associates with sex and age and seems to have a hereditary component, but the precise genomic determinants remain ill-defined.

Methods: Genome-wide association studies previously conducted in 3 cohorts (Genetic Epidemiology Network of Arteriopathy study, January 1, 2006, through December 31, 2012; the combined Nurses' Health Study (NHS), NHS II, and Health Professionals Follow-up Study, January 1, 1994, through December 31, 2003; and the Prevention of Renal and Vascular End-stage Disease study, January 1, 1997, through December 31, 1998) were combined into meta-analyses to evaluate genetic associations with available urinary phenotypes relevant to stone pathogenesis (calcium, magnesium, and uric acid excretion; total urine volume).

Results: One region on chromosome 9q21.13 showed strong evidence of an association with urinary magnesium excretion. The strongest signal in this region was near , whose protein product mediates magnesium transport in the colon and kidney, and , , , and (rs1176815; 1.70×10, with each copy of the A allele corresponding to a daily 5.29-mg decrease in magnesium excretion). The single nucleotide polymorphism (SNP) that achieved genome-wide significance for calcium excretion (rs17216707 on chromosome 20; 1.12×10) was previously associated with fibroblast growth factor 23 levels, which regulate phosphorus and vitamin D metabolism. Urine volume and uric acid excretion did not have any genome-wide significant SNPs.

Conclusion: Common variants near genes important for magnesium metabolism and bone health associate with urinary magnesium and calcium excretion.
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http://dx.doi.org/10.1016/j.mayocpiqo.2019.08.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978610PMC
December 2019

Response to: Heterogeneous Treatment Response by Race Cannot Be Claimed in the Absence of Evidence.

Am J Hypertens 2020 02;33(2):e2

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, College of Pharmacy, University of Florida, Gainesville, Florida.

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http://dx.doi.org/10.1093/ajh/hpz168DOI Listing
February 2020

Genome Wide Analysis Approach Suggests Chromosome 2 Locus to be Associated with Thiazide and Thiazide Like-Diuretics Blood Pressure Response.

Sci Rep 2019 11 21;9(1):17323. Epub 2019 Nov 21.

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, Florida, USA.

Chlorthalidone (CTD) is more potent than hydrochlorothiazide (HCTZ) in reducing blood pressure (BP) in hypertensive patients, though both are plagued with BP response variability. However, there is a void in the literature regarding the genetic determinants contributing to the variability observed in BP response to CTD. We performed a discovery genome wide association analysis of BP response post CTD treatment in African Americans (AA) and European Americans (EA) from the Pharmacogenomic Evaluation of Antihypertensive Responses-2 (PEAR-2) study and replication in an independent cohort of AA and EA treated with HCTZ from the PEAR study, followed by a race specific meta-analysis of the two studies. Successfully replicated SNPs were further validated in beta-blocker treated participants from PEAR-2 and PEAR for opposite direction of association. The replicated and validated signals were further evaluated by protein-protein interaction network analysis. An intronic SNP rs79237970 in the WDR92 (eQTL for PPP3R1) was significantly associated with better DBP response to CTD (p = 5.76 × 10, β = -15.75) in the AA cohort. This SNP further replicated in PEAR (p = 0.00046, β = -9.815) with a genome wide significant meta-analysis p-value of 8.49 × 10. This variant was further validated for opposite association in two β-blockers treated cohorts from PEAR-2 metoprolol (p = 9.9 × 10, β = 7.47) and PEAR atenolol (p = 0.04, β = 4.36) for association with DBP. Studies have implicated WDR92 in coronary artery damage. PPP3R1 is the regulatory subunit of the calcineurin complex. Use of calcineurin inhibitors is associated with HTN. Studies have also shown polymorphisms in PPP3R1 to be associated with ventricular hypertrophy in AA hypertensive patients. Protein-protein interaction analysis further identified important hypertension related pathways such as inositol phosphate-mediated signaling and calcineurin-NFAT signaling cascade as important biological process associated with PPP3R1 which further strengthen the potential importance of this signal. These data collectively suggest that WDR92 and PPP3R1 are novel candidates that may help explain the genetic underpinnings of BP response of thiazide and thiazide-like diuretics and help identify the patients better suited for thiazide and thiazide-like diuretics compared to β-blockers for improved BP management. This may further help advance personalized approaches to antihypertensive therapy.
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http://dx.doi.org/10.1038/s41598-019-53345-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6872535PMC
November 2019

Intrinsic and extrinsic epigenetic age acceleration are associated with hypertensive target organ damage in older African Americans.

BMC Med Genomics 2019 10 22;12(1):141. Epub 2019 Oct 22.

Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA.

Background: Epigenetic age acceleration, a measure of biological aging based on DNA methylation, is associated with cardiovascular mortality. However, little is known about its relationship with hypertensive target organ damage to the heart, kidneys, brain, and peripheral arteries.

Methods: We investigated associations between intrinsic (IEAA) or extrinsic (EEAA) epigenetic age acceleration, blood pressure, and six types of organ damage in a primarily hypertensive cohort of 1390 African Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. DNA methylation from peripheral blood leukocytes was collected at baseline (1996-2000), and measures of target organ damage were assessed in a follow-up visit (2000-2004). Linear regression with generalized estimating equations was used to test for associations between epigenetic age acceleration and target organ damage, as well as effect modification of epigenetic age by blood pressure or sex. Sequential Oligogenic Linkage Analysis Routines (SOLAR) was used to test for evidence of shared genetic and/or environmental effects between epigenetic age acceleration and organ damage pairs that were significantly associated.

Results: After adjustment for sex, chronological age, and time between methylation and organ damage measures, higher IEAA was associated with higher urine albumin to creatinine ratio (UACR, p = 0.004), relative wall thickness (RWT, p = 0.022), and left ventricular mass index (LVMI, p = 0.007), and with lower ankle-brachial index (ABI, p = 0.014). EEAA was associated with higher LVMI (p = 0.005). Target organ damage associations for all but IEAA with LVMI remained significant after further adjustment for blood pressure and antihypertensive use (p < 0.05). Further adjustment for diabetes attenuated the IEAA associations with UACR and RWT, and adjustment for smoking attenuated the IEAA association with ABI. No effect modification by age or sex was observed.

Conclusions: Measures of epigenetic age acceleration may help to better characterize the functional mechanisms underlying organ damage from cellular aging and/or hypertension. These measures may act as subclinical biomarkers for damage to the kidney, heart, and peripheral vasculature; however more research is needed to determine whether these relationships remain independent of lifestyle factors and comorbidities.
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http://dx.doi.org/10.1186/s12920-019-0585-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806502PMC
October 2019

Hypertensive APOL1 risk allele carriers demonstrate greater blood pressure reduction with angiotensin receptor blockade compared to low risk carriers.

PLoS One 2019 18;14(9):e0221957. Epub 2019 Sep 18.

Section of Nephrology, University of Chicago, Chicago, Illinois, United States of America.

Background: Hypertension (HTN) disproportionately affects African Americans (AAs), who respond better to thiazide diuretics than other antihypertensives. Variants of the APOL1 gene found in AAs are associated with a higher rate of kidney disease and play a complex role in cardiovascular disease.

Methods: AA subjects from four HTN trials (n = 961) (GERA1, GERA2, PEAR1, and PEAR2) were evaluated for blood pressure (BP) response based on APOL1 genotype after 4-9 weeks of monotherapy with thiazides, beta blockers, or candesartan. APOL1 G1 and G2 variants were determined by direct sequencing or imputation.

Results: Baseline systolic BP (SBP) and diastolic BP (DBP) levels did not differ based on APOL1 genotype. Subjects with 1-2 APOL1 risk alleles had a greater SBP response to candesartan (-12.2 +/- 1.2 vs -7.5 +/- 1.8 mmHg, p = 0.03; GERA2), and a greater decline in albuminuria with candesartan (-8.3 +/- 3.1 vs +3.7 +/- 4.3 mg/day, p = 0.02). APOL1 genotype did not associate with BP response to thiazides or beta blockers. GWAS was performed to determine associations with BP response to candesartan depending on APOL1 genotype. While no SNPs reached genome wide significance, SNP rs10113352, intronic in CSMD1, predicted greater office SBP response to candesartan (p = 3.7 x 10-7) in those with 1-2 risk alleles, while SNP rs286856, intronic in DPP6, predicted greater office SBP response (p = 3.2 x 10-7) in those with 0 risk alleles.

Conclusions: Hypertensive AAs without overt kidney disease who carry 1 or more APOL1 risk variants have a greater BP and albuminuria reduction in response to candesartan therapy. BP response to thiazides or beta blockers did not differ by APOL1 genotype. Future studies confirming this initial finding in an independent cohort are required.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0221957PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6750571PMC
March 2020

Gene Variants at Loci Related to Blood Pressure Account for Variation in Response to Antihypertensive Drugs Between Black and White Individuals.

Hypertension 2019 09 22;74(3):614-622. Epub 2019 Jul 22.

Department of Clinical Pharmacology, King's College London British Heart Foundation Centre, School of Cardiovascular Medicine and Sciences (L.F., P.C.), King's College London, United Kingdom.

Selection of antihypertensive treatment according to self-defined ethnicity is recommended by some guidelines but might be better guided by individual genotype rather than ethnicity or race. We compared the extent to which variation in blood pressure response across different ethnicities may be explained by genetic factors: genetically defined ancestry and gene variants at loci known to be associated with blood pressure. We analyzed data from 5 trials in which genotyping had been performed (n=4696) and in which treatment responses to β-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blocker, thiazide or thiazide-like diuretic and calcium channel blocker were available. Genetically defined ancestry for proportion of African ancestry was computed using the 1000 genomes population database as a reference. Differences in response to the thiazide diuretic hydrochlorothiazide, the β-blockers atenolol and metoprolol, the angiotensin-converting enzyme inhibitor lisinopril, and the angiotensin receptor blocker candesartan were more closely associated to genetically defined ancestry than self-defined ethnicity in admixed subjects. A relatively small number of gene variants related to loci associated with drug-signaling pathways (KCNK3, SULT1C3, AMH, PDE3A, PLCE1, PRKAG2) with large effect size (-3.5 to +3.5 mm Hg difference in response per allele) and differing allele frequencies in black versus white individuals explained a large proportion of the difference in response to candesartan and hydrochlorothiazide between these groups. These findings suggest that a genomic precision medicine approach can be used to individualize antihypertensive treatment within and across populations without recourse to surrogates of genetic structure such as self-defined ethnicity.
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http://dx.doi.org/10.1161/HYPERTENSIONAHA.118.12177DOI Listing
September 2019

β -Adrenergic Receptor Gene Affects the Heart Rate Response of β-Blockers: Evidence From 3 Clinical Studies.

J Clin Pharmacol 2019 11 14;59(11):1462-1470. Epub 2019 May 14.

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, College of Pharmacy, University of Florida, Gainesville, FL, USA.

β-Blockers' heart rate (HR)-lowering effect is an important determinant of the effectiveness for this class of drugs, yet it is variable among β-blocker-treated patients. To date, genetic studies have revealed several genetic signals associated with HR response to β-blockers. However, these genetic signals have not been consistently replicated across multiple independent cohorts. Here we sought to use data from 3 hypertension clinical trials to validate single-nucleotide polymorphisms (SNPs) previously associated with the HR response to β-blockers. Using linear regression analysis, we investigated the effects of 6 SNPs in 3 genes, including ADRB1, ADRB2, and GNB3, relative to the HR response following β-blocker used in the PEAR (n = 757), PEAR-2 (n = 368), and INVEST (n = 1401) trials, adjusting for baseline HR, age, sex, and ancestry. Atenolol was used in PEAR and INVEST, and metoprolol was used in PEAR-2. We found that rs1042714 and rs1042713 in ADRB2 were significantly associated with HR response to both β-blockers in whites (rs1042714 C-allele carriers, meta-analysis β = -0.95 beats per minute [bpm], meta-analysis P = 3×10 ; rs1042713 A-allele carriers, meta-analysis β = -1.15 bpm, meta-analysis P = 2×10 ). In conclusion, the results of our analyses provide strong evidence to support the hypothesis that rs1042714 and rs1042713 in the ADRB2 gene are important predictors of HR response to cardioselective β-blockade in hypertensive patient cohorts.
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http://dx.doi.org/10.1002/jcph.1443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6773496PMC
November 2019

Genomic Association Analysis Reveals Variants Associated With Blood Pressure Response to Beta-Blockers in European Americans.

Clin Transl Sci 2019 09 4;12(5):497-504. Epub 2019 Jun 4.

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, Florida, USA.

European Americans (EA) have a better antihypertensive response to β-blockers when compared with African Americans, albeit with some variability. We undertook a genomewide association study to elucidate the underlying genetic determinants in EA contributing to this variability in blood pressure (BP) response. A discovery genomewide association study of change in BP post-metoprolol treatment was performed in EA participants (n = 201) from the Pharmacogenomic Evaluation of Antihypertensive Responses-2 (PEAR-2) study and tested for replication in the atenolol-treated EA from the PEAR study (n = 233). Rs294610 in the FGD5, which encodes for FYVE, RhoGEF and PH Domain Containing 5, (expression quantitative trait loci for FGD5 in the small intestine) was significantly associated with increased diastolic BP response to β-blockers in the PEAR-2 study (P = 3.41 × 10 , β = -2.70) and replicated (P = 0.01, β = -1.17) in the PEAR study. Post-meta-analysis of these studies, an additional single nucleotide polymorphism rs45545233 in the SLC4A1, encoding for Solute Carrier Family 4 Member 1, (expression quantitative trait loci for dual specificity phosphatase 3 in the artery tibial) was identified that was significantly associated with a poor response to β-blockers (P = 3.43 × 10 , β = 4.57) and was replicated in the atenolol add-on cohort (P = 0.007, β = 4.97). We identified variants in FGD5 and SLC4A1, which have been previously cited as candidate genes for hypertension, to be associated with a β-blocker BP response in EA. Further elucidation is warranted of the underlying mechanisms of these variants and genes by which they influence the BP response to β-blockers.
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http://dx.doi.org/10.1111/cts.12643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6742943PMC
September 2019

Multi-ancestry genome-wide gene-smoking interaction study of 387,272 individuals identifies new loci associated with serum lipids.

Nat Genet 2019 04 29;51(4):636-648. Epub 2019 Mar 29.

Human Genomics Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA.

The concentrations of high- and low-density-lipoprotein cholesterol and triglycerides are influenced by smoking, but it is unknown whether genetic associations with lipids may be modified by smoking. We conducted a multi-ancestry genome-wide gene-smoking interaction study in 133,805 individuals with follow-up in an additional 253,467 individuals. Combined meta-analyses identified 13 new loci associated with lipids, some of which were detected only because association differed by smoking status. Additionally, we demonstrate the importance of including diverse populations, particularly in studies of interactions with lifestyle factors, where genomic and lifestyle differences by ancestry may contribute to novel findings.
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http://dx.doi.org/10.1038/s41588-019-0378-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6467258PMC
April 2019

Longitudinal analysis of epigenome-wide DNA methylation reveals novel smoking-related loci in African Americans.

Epigenetics 2019 02 14;14(2):171-184. Epub 2019 Mar 14.

a Department of Epidemiology , School of Public Health, University of Michigan , Ann Arbor , MI , USA.

Changes in DNA methylation may be a potential mechanism that mediates the effects of smoking on physiological function and subsequent disease risk. Given the dynamic nature of the epigenome, longitudinal studies are indispensable for investigating smoking-induced methylation changes over time. Using blood samples collected approximately five years apart in 380 African Americans (mean age 60.7 years) from the Genetic Epidemiology Network of Arteriopathy (GENOA) study, we measured DNA methylation levels using Illumina HumanMethylation BeadChips. We evaluated the association between Phase 1 smoking status and rate of methylation change, using generalized estimating equation models. Among the 6958 CpG sites examined, smoking status was associated with methylation change for 22 CpGs (false discovery rate q < 0.1), with the majority (91%) becoming less methylated over time. Methylation change was greater in ever smokers than never smokers, and the absolute differences in rates of change ranged from 0.18 to 0.77 per decade in M value, equivalent to a value change of 0.013 to 0.047 per decade. Significant enrichment was observed for CpG islands, enhancers, and DNAse hypersensitivity sites (p < 0.05). Although biological pathway analyses were not significant, most of the 22 CpGs were within genes known to be associated with cardiovascular disease, cancers, and aging. In conclusion, we identified epigenetic signatures for cigarette smoking that may have been missed in cross-sectional analyses, providing insight into the epigenetic effect of smoking and highlighting the importance of longitudinal analysis in understanding the dynamic human epigenome.
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http://dx.doi.org/10.1080/15592294.2019.1581589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6557606PMC
February 2019

Effect of plasma MicroRNA on antihypertensive response to beta blockers in the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) studies.

Eur J Pharm Sci 2019 Apr 10;131:93-98. Epub 2019 Feb 10.

Department of Pharmacotherapy and Translational Research, Center for Pharmacogenomics, College of Pharmacy, University of Florida, Gainesville, FL, USA. Electronic address:

β-blockers show variable efficacy as antihypertensives. Herein, we evaluated plasma miRNAs as biomarkers for defining antihypertensive response to β-blockers. Expression of 22 β-blocker pharmacodynamics-related miRNAs was assessed in baseline plasma samples from 30 responders and 30 non-responders to metoprolol from the PEAR-2 study (Discovery). Logistic regression was performed to identify miRNAs significantly associated with metoprolol response. Those miRNAs were profiled in baseline plasma samples from 25 responders and 25 non-responders to atenolol from the PEAR study (validation). In discovery, miR-101, miR-27a, miR-22, miR-19a, and let-7e were significantly associated with metoprolol response (P = 0.01, 0.017, 0.025, 0.025, and 0.04, respectively). In validation, miR-19a was significantly associated with atenolol response (P = 0.038). Meta-analysis between PEAR-2 and PEAR revealed significant association between miR-19a (P = 0.004), miR-101 (P = 0.006), and let-7e (P = 0.012) and β-blocker response. Hence, miR-19a, miR-101, and let-7e, which regulate β1-adrenergic receptor and other β-blocker pharmacodynamics-related genes, may be biomarkers for antihypertensive response to β-blockers.
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http://dx.doi.org/10.1016/j.ejps.2019.02.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6467266PMC
April 2019

Plasma Renin Activity Is a Predictive Biomarker of Blood Pressure Response in European but not in African Americans With Uncomplicated Hypertension.

Am J Hypertens 2019 06;32(7):668-675

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, College of Pharmacy, University of Florida, Gainesville, Florida, USA.

Background: Interindividual variability in blood pressure (BP) response to antihypertensives has been reported. Although plasma renin activity (PRA) is a potential biomarker for personalizing antihypertensive therapy in European American (EA) and African American (AA) hypertensives, clinical utility of PRA-guided prescribing is incompletely understood.

Methods: Using systematic-phased approach, PRA's clinical utility was assessed. After categorizing by baseline PRA, clinic systolic BP (SBP) responses to metoprolol and chlorthalidone were compared in 134 EAs and 102 AAs enrolled in the Pharmacogenomics Evaluation of Antihypertensive Responses-2 (PEAR-2) trial. Receiver operating characteristic (ROC) analysis was conducted in EAs. Data from PEAR-2 AAs were used to estimate an optimal PRA cut point using multivariable linear regression models. The derived cut point in AAs was tested in a meta-analysis of 2 independent AA cohorts, and its sensitivity and specificity were assessed.

Results: EAs with PRA < 0.65 ng/ml/hour had a greater decrease in SBP to chlorthalidone than metoprolol (by -15.9 mm Hg, adjusted P < 0.0001), whereas those with PRA ≥ 0.65 ng/ml/hour had a greater decrease in SBP to metoprolol than chlorthalidone (by 3.3 mm Hg, adjusted P = 0.04). Area under ROC curve (0.69, P = 0.0001) showed that PRA can predict SBP response among EAs. However, we observed no association between PRA and SBP response in PEAR-2 AAs. Among independent AA cohorts, those with PRA ≥ 1.3 ng/ml/hour (PEAR-2-derived cut point) responded better to atenolol/candesartan than hydrochlorothiazide (meta-analysis P = 0.01). However, sensitivity of the derived cut point was 10%.

Conclusions: PRA at the previously established 0.60-0.65 ng/ml/hour cut point is an effective predictive biomarker of BP response in EAs. However, we were unable to identify PRA cut point that could be used to guide antihypertensive selection in AAs.

Trial Registration: NCT01203852, NCT00246519, NCT00005520.
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http://dx.doi.org/10.1093/ajh/hpz022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558666PMC
June 2019

Associations of Mitochondrial and Nuclear Mitochondrial Variants and Genes with Seven Metabolic Traits.

Am J Hum Genet 2019 01 27;104(1):112-138. Epub 2018 Dec 27.

School of Medicine, Division of Endocrinology, Diabetes and Nutrition, and Program for Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.

Mitochondria (MT), the major site of cellular energy production, are under dual genetic control by 37 mitochondrial DNA (mtDNA) genes and numerous nuclear genes (MT-nDNA). In the CHARGEmtDNA+ Consortium, we studied genetic associations of mtDNA and MT-nDNA associations with body mass index (BMI), waist-hip-ratio (WHR), glucose, insulin, HOMA-B, HOMA-IR, and HbA1c. This 45-cohort collaboration comprised 70,775 (insulin) to 170,202 (BMI) pan-ancestry individuals. Validation and imputation of mtDNA variants was followed by single-variant and gene-based association testing. We report two significant common variants, one in MT-ATP6 associated (p ≤ 5E-04) with WHR and one in the D-loop with glucose. Five rare variants in MT-ATP6, MT-ND5, and MT-ND6 associated with BMI, WHR, or insulin. Gene-based meta-analysis identified MT-ND3 associated with BMI (p ≤ 1E-03). We considered 2,282 MT-nDNA candidate gene associations compiled from online summary results for our traits (20 unique studies with 31 dataset consortia's genome-wide associations [GWASs]). Of these, 109 genes associated (p ≤ 1E-06) with at least 1 of our 7 traits. We assessed regulatory features of variants in the 109 genes, cis- and trans-gene expression regulation, and performed enrichment and protein-protein interactions analyses. Of the identified mtDNA and MT-nDNA genes, 79 associated with adipose measures, 49 with glucose/insulin, 13 with risk for type 2 diabetes, and 18 with cardiovascular disease, indicating for pleiotropic effects with health implications. Additionally, 21 genes related to cholesterol, suggesting additional important roles for the genes identified. Our results suggest that mtDNA and MT-nDNA genes and variants reported make important contributions to glucose and insulin metabolism, adipocyte regulation, diabetes, and cardiovascular disease.
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http://dx.doi.org/10.1016/j.ajhg.2018.12.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6323610PMC
January 2019

Targeted sequencing identifies a missense variant in the BEST3 gene associated with antihypertensive response to hydrochlorothiazide.

Pharmacogenet Genomics 2018 11;28(11):251-255

Departments of Pharmacotherapy and Translational Research and Center for Pharmacogenomics.

Chromosome 12q15 was identified in Genetic Epidemiology of Response Assessment (GERA) and replicated in Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) for its association with blood pressure (BP) response to hydrochlorothiazide (HCTZ). However, the functional variant is unknown and we aimed to identify the likely functional variants through targeted sequencing. The chromosome 12q15 region was sequenced in 397 best and worst responders to HCTZ in PEAR (N=199) and GERA (N=198) hypertensive study participants. Logistic regression was used for the association analysis adjusting for age, sex, race, and principal components 1 and 2. For validation, the significant single nucleotide polymorphism was tested for association with the change in systolic (ΔSBP) and diastolic BP (ΔDBP) post-treatment in the entire PEAR (N=370) and GERA (N=570) cohorts. A novel missense polymorphism (G>A, Pro383Leu) in BEST3, rs61747221, was significantly associated with better HCTZ response (P=0.0021, odds ratio=2.05). It was validated in the entire cohort of PEAR (ΔSBP: P=0.021, β=-1.60, ΔDBP: P=0.023, β=-1.08) and GERA (ΔSBP: P=0.028, β=-1.95, ΔDBP: P=0.032, β=-1.28). BEST3 encodes the calcium sensitive chloride channel in the vascular smooth muscle implicated in the regulation of BP, especially in response to vasoconstrictors like angiotensin II. These results suggest that BEST3 is involved in the chronic BP lowering mechanism of thiazides and highlight its importance as a genetic predictor of the BP response to thiazide diuretics.
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http://dx.doi.org/10.1097/FPC.0000000000000353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6262886PMC
November 2018

Adverse effects of long-term weight gain on microvascular endothelial function.

Obes Res Clin Pract 2018 Sep - Oct;12(5):452-458. Epub 2018 Jun 28.

Department of Medicine, Division of Cardiovascular Diseases, Mayo Clinic, 200 First St. SW. Rochester, MN 55901, USA. Electronic address:

Background: Endothelial dysfunction is the first stage of the atherosclerotic cascade, and independently associated with cardiovascular events. We evaluated the associations of longitudinal changes in weight, waist circumference, body fat percentage and lean mass index with changes in endothelial function.

Methods: 521 community-based subjects who belonged to hypertensive sibships and had no history of myocardial infarction or stroke had their anthropometric measures and endothelial function assessed a mean of 8.5 years apart. Endothelial function was assessed with brachial artery ultrasound, yielding measures of flow-mediated dilation and reactive hyperemia. We used multivariable linear regression with generalised estimating equations to assess the associations of longitudinal changes (Δ) in anthropometric measures with Δ flow-mediated dilation and reactive hyperemia, adjusting for potential confounders.

Results: Mean±standard deviation age was 57.6±8.7years, 58% were women, and 72% were hypertensive. Most (84%) were overweight or obese at baseline. At end of follow-up, flow-mediated dilation and reactive hyperemia increased by 1.9±7.6% and 51.2±605.8% on average, respectively. In multivariable linear regression, changes in anthropometric measures were not associated with changes in flow-mediated dilation. However, Δ weight (β±SE: -9.00±2.35), Δ waist circumference (-6.78±2.21) and Δ body fat percentage (-19.72±5.62, P<0.0001 for each) were inversely associated with Δ reactive hyperemia. Δ lean mass index was not associated with Δ reactive hyperemia.

Conclusions: Long-term increases in weight, waist circumference and body fat percentage are associated with progressive worsening of microvascular endothelial function, but not conduit vessel endothelial function, in subjects without a history of cardiovascular events, independently of risk factors.
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http://dx.doi.org/10.1016/j.orcp.2018.06.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6146400PMC
March 2019

Exome Chip Analysis Identifies Low-Frequency and Rare Variants in MRPL38 for White Matter Hyperintensities on Brain Magnetic Resonance Imaging.

Stroke 2018 08;49(8):1812-1819

Department of Biochemistry (D.W.B., N.D.P.), Wake Forest School of Medicine, Winston-Salem, NC.

Background and Purpose- White matter hyperintensities (WMH) on brain magnetic resonance imaging are typical signs of cerebral small vessel disease and may indicate various preclinical, age-related neurological disorders, such as stroke. Though WMH are highly heritable, known common variants explain a small proportion of the WMH variance. The contribution of low-frequency/rare coding variants to WMH burden has not been explored. Methods- In the discovery sample we recruited 20 719 stroke/dementia-free adults from 13 population-based cohort studies within the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium, among which 17 790 were of European ancestry and 2929 of African ancestry. We genotyped these participants at ≈250 000 mostly exonic variants with Illumina HumanExome BeadChip arrays. We performed ethnicity-specific linear regression on rank-normalized WMH in each study separately, which were then combined in meta-analyses to test for association with single variants and genes aggregating the effects of putatively functional low-frequency/rare variants. We then sought replication of the top findings in 1192 adults (European ancestry) with whole exome/genome sequencing data from 2 independent studies. Results- At 17q25, we confirmed the association of multiple common variants in TRIM65, FBF1, and ACOX1 ( P<6×10). We also identified a novel association with 2 low-frequency nonsynonymous variants in MRPL38 (lead, rs34136221; P=4.5×10) partially independent of known common signal ( P=1.4×10). We further identified a locus at 2q33 containing common variants in NBEAL1, CARF, and WDR12 (lead, rs2351524; P=1.9×10). Although our novel findings were not replicated because of limited power and possible differences in study design, meta-analysis of the discovery and replication samples yielded stronger association for the 2 low-frequency MRPL38 variants ( P=2.8×10). Conclusions- Both common and low-frequency/rare functional variants influence WMH. Larger replication and experimental follow-up are essential to confirm our findings and uncover the biological causal mechanisms of age-related WMH.
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http://dx.doi.org/10.1161/STROKEAHA.118.020689DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6202149PMC
August 2018

Genome-wide meta-analysis of macronutrient intake of 91,114 European ancestry participants from the cohorts for heart and aging research in genomic epidemiology consortium.

Mol Psychiatry 2019 12 9;24(12):1920-1932. Epub 2018 Jul 9.

Department of Clinical Chemistry, Fimlab Laboratories, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.

Macronutrient intake, the proportion of calories consumed from carbohydrate, fat, and protein, is an important risk factor for metabolic diseases with significant familial aggregation. Previous studies have identified two genetic loci for macronutrient intake, but incomplete coverage of genetic variation and modest sample sizes have hindered the discovery of additional loci. Here, we expanded the genetic landscape of macronutrient intake, identifying 12 suggestively significant loci (P < 1 × 10) associated with intake of any macronutrient in 91,114 European ancestry participants. Four loci replicated and reached genome-wide significance in a combined meta-analysis including 123,659 European descent participants, unraveling two novel loci; a common variant in RARB locus for carbohydrate intake and a rare variant in DRAM1 locus for protein intake, and corroborating earlier FGF21 and FTO findings. In additional analysis of 144,770 participants from the UK Biobank, all identified associations from the two-stage analysis were confirmed except for DRAM1. Identified loci might have implications in brain and adipose tissue biology and have clinical impact in obesity-related phenotypes. Our findings provide new insight into biological functions related to macronutrient intake.
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http://dx.doi.org/10.1038/s41380-018-0079-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326896PMC
December 2019

Blood pressure signature genes and blood pressure response to thiazide diuretics: results from the PEAR and PEAR-2 studies.

BMC Med Genomics 2018 Jun 20;11(1):55. Epub 2018 Jun 20.

Center for Pharmacogenomics, Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, P.O.Box 100484, Gainesville, FL, 32610-0486, USA.

Background: Recently, 34 genes had been associated with differential expression relative to blood pressure (BP)/ hypertension (HTN). We hypothesize that some of the genes associated with BP/HTN are also associated with BP response to antihypertensive treatment with thiazide diuretics.

Methods: We assessed these 34 genes for association with differential expression to BP response to thiazide diuretics with RNA sequencing in whole blood samples from 150 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) and PEAR-2 studies. PEAR white and PEAR-2 white and black participants (n = 50 for each group) were selected based on the upper and lower quartile of BP response to hydrochlorothiazide (HCTZ) and to chlorthalidone.

Results: FOS, DUSP1 and PPP1R15A were differentially expressed across all cohorts (meta-analysis p-value < 2.0 × 10), and responders to HCTZ or chlorthalidone presented up-regulated transcripts. Rs11065987 in chromosome 12, a trans-eQTL for expression of FOS, PPP1R15A and other genes, is also associated with BP response to HCTZ in PEAR whites (SBP: β = - 2.1; p = 1.7 × 10; DBP: β = - 1.4; p = 2.9 × 10).

Conclusions: These findings suggest FOS, DUSP1 and PPP1R15A as potential molecular determinants of antihypertensive response to thiazide diuretics.

Trial Registration: NCT00246519 , NCT01203852 www.clinicaltrials.gov.
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http://dx.doi.org/10.1186/s12920-018-0370-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6011347PMC
June 2018

Novel genetic associations for blood pressure identified via gene-alcohol interaction in up to 570K individuals across multiple ancestries.

PLoS One 2018 18;13(6):e0198166. Epub 2018 Jun 18.

Icelandic Heart Association, Kopavogur, Iceland.

Heavy alcohol consumption is an established risk factor for hypertension; the mechanism by which alcohol consumption impact blood pressure (BP) regulation remains unknown. We hypothesized that a genome-wide association study accounting for gene-alcohol consumption interaction for BP might identify additional BP loci and contribute to the understanding of alcohol-related BP regulation. We conducted a large two-stage investigation incorporating joint testing of main genetic effects and single nucleotide variant (SNV)-alcohol consumption interactions. In Stage 1, genome-wide discovery meta-analyses in ≈131K individuals across several ancestry groups yielded 3,514 SNVs (245 loci) with suggestive evidence of association (P < 1.0 x 10-5). In Stage 2, these SNVs were tested for independent external replication in ≈440K individuals across multiple ancestries. We identified and replicated (at Bonferroni correction threshold) five novel BP loci (380 SNVs in 21 genes) and 49 previously reported BP loci (2,159 SNVs in 109 genes) in European ancestry, and in multi-ancestry meta-analyses (P < 5.0 x 10-8). For African ancestry samples, we detected 18 potentially novel BP loci (P < 5.0 x 10-8) in Stage 1 that warrant further replication. Additionally, correlated meta-analysis identified eight novel BP loci (11 genes). Several genes in these loci (e.g., PINX1, GATA4, BLK, FTO and GABBR2) have been previously reported to be associated with alcohol consumption. These findings provide insights into the role of alcohol consumption in the genetic architecture of hypertension.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0198166PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005576PMC
January 2019

DNA methylation in the APOE genomic region is associated with cognitive function in African Americans.

BMC Med Genomics 2018 05 8;11(1):43. Epub 2018 May 8.

Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, 4602 SPH Tower, Ann Arbor, MI, 48109-2029, USA.

Background: Genetic variations in apolipoprotein E (APOE) and proximal genes (PVRL2, TOMM40, and APOC1) are associated with cognitive function and dementia, particularly Alzheimer's disease. Epigenetic mechanisms such as DNA methylation play a central role in the regulation of gene expression. Recent studies have found evidence that DNA methylation may contribute to the pathogenesis of dementia, but its association with cognitive function in populations without dementia remains unclear.

Methods: We assessed DNA methylation levels of 48 CpG sites in the APOE genomic region in peripheral blood leukocytes collected from 289 African Americans (mean age = 67 years) from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. Using linear regression, we examined the relationship between methylation in the APOE genomic region and multiple cognitive measures including learning, memory, processing speed, concentration, language and global cognitive function.

Results: We identified eight CpG sites in three genes (PVRL2, TOMM40, and APOE) that showed an inverse association between methylation level and delayed recall, a measure of memory, after adjusting for age and sex (False Discovery Rate q-value < 0.1). All eight CpGs are located in either CpG islands (CGIs) or CGI shelves, and six of them are in promoter regions. Education and APOE ε4 carrier status significantly modified the effect of methylation in cg08583001 (PVRL2) and cg22024783 (TOMM40), respectively. Together, methylation of the eight CpGs explained an additional 8.7% of the variance in delayed recall, after adjustment for age, sex, education, and APOE ε4 carrier status. Methylation was not significantly associated with any other cognitive measures.

Conclusions: Our results suggest that methylation levels at multiple CpGs in the APOE genomic region are inversely associated with delayed recall during normal cognitive aging, even after accounting for known genetic predictors for cognition. Our findings highlight the important role of epigenetic mechanisms in influencing cognitive performance, and suggest that changes in blood methylation may be an early indicator of individuals at risk for dementia as well as potential targets for intervention in asymptomatic populations.
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http://dx.doi.org/10.1186/s12920-018-0363-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5941603PMC
May 2018

Genetic Variants Influencing Plasma Renin Activity in Hypertensive Patients From the PEAR Study (Pharmacogenomic Evaluation of Antihypertensive Responses).

Circ Genom Precis Med 2018 04;11(4):e001854

Department of Pharmacotherapy and Translational Research, Center for Pharmacogenomics (C.W.M., O.M., A.C.C.S., N.M.E.R., M.K.-S., M.S., J.G.G., R.M.C.-D., Y.G., J.A.J.), Department of Pharmaceutical Outcomes and Policy (C.D.), Department of Pharmaceutics, College of Pharmacy (A.N.D., R.S.P.S.), Genetics & Genomics Graduate Program, Genetics Institute (A.C.C.S., Y.S.), Department of Biology, College of Liberal Arts and Sciences (W.M.), Department of Community Health and Family Medicine, College of Medicine (J.G.G.), and Division of Cardiovascular Medicine, Department of Medicine (R.M.C.-D., J.A.J.), University of Florida, Gainesville; School of Pharmacy, College of Health Professions, Pacific University, Hillsboro, OR (M.K.-S.); Department of Clinical Pharmacy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt (M.S.); Division of Biomedical Statistics and Informatics, Department of Health Sciences Research (K.R.B.) and Division of Nephrology and Hypertension, Department of Medicine (S.T.T.), Mayo Clinic, Rochester, MN; Human Genetics Center, Institute of Molecular Medicine, University of Texas Health Science Center, Houston (E.B.); Section of Nephrology, Department of Medicine, University of Chicago, IL (A.B.C.); Department of Biomedical Informatics, Center for Pharmacogenomics (A.W.) and Department of Cancer Biology and Genetics, College of Medicine (W.S.), Ohio State University, Columbus; and Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX (S.E.S.).

Background: Plasma renin is an important regulator of blood pressure (BP). Plasma renin activity (PRA) has been shown to correlate with variability in BP response to antihypertensive agents. We conducted a genome-wide association study to identify single-nucleotide polymorphisms (SNPs) associated with baseline PRA using data from the PEAR study (Pharmacogenomic Evaluation of Antihypertensive Responses).

Methods: Multiple linear regression analysis was performed in 461 whites and 297 blacks using an additive model, adjusting for age, sex, and ancestry-specific principal components. Top SNPs were prioritized by testing the expected direction of association for BP response to atenolol and hydrochlorothiazide. Top regions from the BP response prioritization were tested for functional evidence through differences in gene expression by genotype using RNA sequencing data. Regions with functional evidence were assessed for replication with baseline PRA in an independent study (PEAR-2).

Results: Our top SNP rs3784921 was in the gene region. The G allele of rs3784921 was associated with higher baseline PRA (β=0.47; =2.09×10) and smaller systolic BP reduction in response to hydrochlorothiazide (β=2.97; 1-sided =0.006). In addition, expression differed by rs3784921 genotype (=0.007), and rs1802409, a proxy SNP for rs3784921 (=0.98-1.00), replicated in PEAR-2 (β=0.15; 1-sided =0.038). Additional SNPs associated with baseline PRA that passed BP response prioritization were in/near the genes and CONCLUSIONS: We identified multiple regions associated with baseline PRA that were prioritized through BP response signals to 2 mechanistically different antihypertensive drugs.

Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00246519.
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http://dx.doi.org/10.1161/CIRCGEN.117.001854DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5901893PMC
April 2018

Genome Wide Association Study Identifies the Locus to be Associated With Chlorthalidone Induced Glucose Increase in Hypertensive Patients.

J Am Heart Assoc 2018 03 9;7(6). Epub 2018 Mar 9.

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, University of Florida, Gainesville, FL.

Background: Thiazide and thiazide-like diuretics are first-line medications for treating uncomplicated hypertension. However, their use has been associated with adverse metabolic events, including hyperglycemia and incident diabetes mellitus, with incompletely understood mechanisms. Our goal was to identify genomic variants associated with thiazide-like diuretic/chlorthalidone-induced glucose change.

Methods And Results: Genome-wide analysis of glucose change after treatment with chlorthalidone was performed by race among the white (n=175) and black (n=135) participants from the PEAR-2 (Pharmacogenomic Evaluation of Antihypertensive Responses-2). Single-nucleotide polymorphisms with <5×10 were further prioritized using in silico analysis based on their expression quantitative trait loci function. Among blacks, an intronic single-nucleotide polymorphism (rs9943291) in the was associated with increase in glucose levels following chlorthalidone treatment (ß=12.5; =4.17×10). G-allele carriers of had higher glucose levels (glucose change=+16.29 mg/dL) post chlorthalidone treatment compared with noncarriers of G allele (glucose change=+2.80 mg/dL). This association was successfully replicated in an independent replication cohort of hydrochlorothiazide-treated participants from the PEAR study (ß=5.54; =0.023). A meta-analysis of the 2 studies was performed by race in Meta-Analysis Helper, where this single-nucleotide polymorphism, rs9943291, was genome-wide significant with a meta-analysis value of 3.71×10. , a part of the HMG-CoA synthase family, is important for ketogenesis and cholesterol synthesis pathways that are essential in glucose homeostasis.

Conclusions: These results suggest that is a promising candidate gene involved in chlorthalidone and Hydrochlorothiazide (HCTZ)-induced glucose change. This may provide insights into the mechanisms involved in thiazide-induced hyperglycemia that may ultimately facilitate personalized approaches to antihypertensive selection for hypertension treatment.

Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00246519 and NCT01203852.
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http://dx.doi.org/10.1161/JAHA.117.007339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5907544PMC
March 2018

Genome-Wide Association Approach Identified Novel Genetic Predictors of Heart Rate Response to β-Blockers.

J Am Heart Assoc 2018 02 24;7(5). Epub 2018 Feb 24.

Department of Pharmacotherapy and Translational Research and Center for Pharmacogenomics, College of Pharmacy, University of Florida, Gainesville, FL

Background: For many indications, the negative chronotropic effect of β-blockers is important to their efficacy, yet the heart rate (HR) response to β-blockers varies. Herein, we sought to use a genome-wide association approach to identify novel single nucleotide polymorphisms (SNPs) associated with HR response to β-blockers.

Methods And Results: We first performed 4 genome-wide association analyses for HR response to atenolol (a β1-adrenergic receptor blocker) as: (1) monotherapy or (2) add-on therapy, in 426 whites and 273 blacks separately from the PEAR (Pharmacogenomic Evaluation of Antihypertensive Responses) study. A meta-analysis was then performed between the genome-wide association analysis performed in PEAR atenolol monotherapy and add-on therapy, in each race separately, using the inverse variance method assuming fixed effects. From this analysis, SNPs associated with HR response to atenolol at a <1E-05 were tested for replication in whites (n=200) and blacks (n=168) treated with metoprolol (a β1-adrenergic receptor blocker). From the genome-wide association meta-analyses, SNP rs17117817 near olfactory receptor family10 subfamily-p-member1 (), and SNP rs2364349 in sorting nexin-9 () replicated in blacks. The combined studies meta-analysis values for the rs17117817 and rs2364349 reached genome-wide significance (rs17117817G-allele; Meta-β=5.53 beats per minute, Meta-=2E-09 and rs2364349 A-allele; Meta-β=3.5 beats per minute, Meta-=1E-08). Additionally, SNPs in the and gene regions were also associated with HR response in whites.

Conclusions: This study highlights and as novel genes associated with changes in HR in response to β-blockers.

Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00246519.
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http://dx.doi.org/10.1161/JAHA.117.006463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5866313PMC
February 2018
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