Joshua Keefe, MD, PhD

All Publications

• Atrial fibroblast-derived macrophage migration inhibitory factor promotes atrial macrophage accumulation in postoperative atrial fibrillation. JCI insight Keefe, J. A., Navarro-Garcia, J. A., Zhao, S., Chelu, M. G., Wehrens, X. H. 2025; 10 (18)

  Abstract

  
  New study: Blocking MIF protein prevents irregular heartbeats after surgery by reducing harmful immune cell buildup in the atria.

  View details for DOI 10.1172/jci.insight.190756

  View details for PubMedID 40811033

  View details for PubMedCentralID PMC12487863

• Macrophage-mediated IL-6 signaling drives ryanodine receptor-2 calcium leak in postoperative atrial fibrillation. The Journal of clinical investigation Keefe, J. A., Aguilar-Sanchez, Y., Navarro-Garcia, J. A., Ong, I., Li, L., Paasche, A., Abu-Taha, I., Tekook, M. A., Bruns, F., Zhao, S., Kamler, M., Shen, Y. H., Chelu, M. G., Li, N., Dobrev, D., Wehrens, X. H. 2025; 135 (9)

  Abstract

  Postoperative atrial fibrillation (poAF) is AF occurring days after surgery, with a prevalence of 33% among patients undergoing open-heart surgery. The degree of postoperative inflammation correlates with poAF risk, but less is known about the cellular and molecular mechanisms driving postoperative atrial arrhythmogenesis. We performed single-cell RNA-seq comparing atrial nonmyocytes from mice with and without poAF, which revealed infiltrating CCR2+ macrophages to be the most altered cell type. Pseudotime trajectory analyses identified Il-6 as a gene of interest driving in macrophages, which we confirmed in pericardial fluid collected from human patients after cardiac surgery. Indeed, macrophage depletion and macrophage-specific Il6ra conditional knockout (cKO) prevented poAF in mice. Downstream STAT3 inhibition with TTI-101 and cardiomyocyte-specific Stat3 cKO rescued poAF, indicating a proarrhythmogenic role of STAT3 in poAF development. Confocal imaging in isolated atrial cardiomyocytes (ACMs) uncovered what we believe to be a novel link between STAT3 and CaMKII-mediated ryanodine receptor-2 (RyR2)-Ser(S)2814 phosphorylation. Indeed, nonphosphorylatable RyR2S2814A mice were protected from poAF, and CaMKII inhibition prevented arrhythmogenic Ca2+ mishandling in ACMs from mice with poAF. Altogether, we provide multiomic, biochemical, and functional evidence from mice and humans that IL-6-STAT3-CaMKII signaling driven by infiltrating atrial macrophages is a pivotal driver of poAF, which portends therapeutic utility for poAF prevention.

  View details for DOI 10.1172/JCI187711

  View details for PubMedID 40048254

  View details for PubMedCentralID PMC12043083

• Immune cells and arrhythmias. Cardiovascular research Keefe, J. A., Wang, J., Song, J., Ni, L., Wehrens, X. H. 2025; 121 (3): 382-395

  Abstract

  Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide. Emerging evidence has demonstrated that resident and infiltrating cardiac immune cells play direct, mechanistic roles in arrhythmia onset and progression. In this review, we provide a comprehensive summary and expert commentary on the role of each immune cell subtype in the pathogenesis of atrial and ventricular arrhythmias.

  View details for DOI 10.1093/cvr/cvaf017

  View details for PubMedID 39937651

  View details for PubMedCentralID PMC12038251

• Tachycardia and Atrial Fibrillation-Related Cardiomyopathies: Potential Mechanisms and Current Therapies. JACC. Heart failure Keefe, J. A., Garber, R., McCauley, M. D., Wehrens, X. H. 2024; 12 (4): 605-615

  Abstract

  Atrial fibrillation (AF) is associated with an increased risk of new-onset ventricular contractile dysfunction, termed arrhythmia-induced cardiomyopathy (AIC). Although cardioembolic stroke remains the most feared and widely studied complication of AF, AIC is also a clinically important consequence of AF that portends significant morbidity and mortality to patients with AF. Current treatments are aimed at restoring sinus rhythm through catheter ablation and rate and rhythm control, but these treatments do not target the underlying molecular mechanisms driving the progression from AF to AIC. Here, we describe the clinical features of the various AIC subtypes, discuss the pathophysiologic mechanisms driving the progression from AF to AIC, and review the evidence surrounding current treatment options. In this review, we aim to identify key knowledge gaps that will enable the development of more effective AIC therapies that target cellular and molecular mechanisms.

  View details for DOI 10.1016/j.jchf.2023.11.016

  View details for PubMedID 38206235

• Cyclic AMP-dependent regulation of ryanodine receptors in healthy and diseased hearts. Journal of molecular and cellular cardiology Hulsurkar, M. M., Ong, I., Keefe, J. A., Abu-Taha, I. H., Dobrev, D., Wehrens, X. H. 2026; 211: 53-62

  Abstract

  Cyclic adenosine monophosphate (cAMP) is a critical second messenger in cardiomyocytes, regulating essential cellular functions. Upon G-protein-coupled receptor stimulation, adenylyl cyclase (AC) synthesizes cAMP, which phosphodiesterase (PDE) enzymes subsequently degrade. Recent studies challenge the traditional view of uniform cAMP signaling, revealing nanodomain-specific regulation within cardiomyocytes. This localized cAMP signaling modulates key Ca2+-handling proteins, including ryanodine receptor type-2 (RyR2), through channel-bound protein kinases and PDEs. Additionally, nucleoside-diphosphate kinases (NDPKs), particularly NDPK-C, contribute to cAMP synthesis and RyR2 regulation. Elevated NDPK-C levels in failing hearts correlate with increased cAMP levels, enhanced sarcoplasmic reticulum Ca2+ release, and cardiac arrhythmias. Furthermore, cAMP influences the expression of Ca2+-handling proteins. This review examines the mechanisms governing cAMP levels in the sarcoplasmic reticulum nanodomain and their role in regulating RyR2 function in healthy and diseased hearts.

  View details for DOI 10.1016/j.yjmcc.2025.11.013

  View details for PubMedID 41297693

  View details for PubMedCentralID PMC12968982

• Macrophage Migration Inhibitory Factor: the Next Adjunct to Reperfusion Therapy in Acute Myocardial Infarction? Cardiovascular drugs and therapy Keefe, J. A., Wehrens, X. H. 2025; 39 (6): 1239-1242

  View details for DOI 10.1007/s10557-025-07726-w

  View details for PubMedID 40448808

  View details for PubMedCentralID 7097468

• Multiomic and electrophysiologic analyses reveal that an inherited MRC2 variant causes fibroblast dysfunction and increased atrial fibrillation susceptibility. American journal of physiology. Heart and circulatory physiology Ho, K. S., Keefe, J. A., Zhao, S., Hulsurkar, M. M., Jung, S. Y., Samee, M. A., Wehrens, X. H. 2025; 329 (5): H1055-H1071

  Abstract

  A recent study identified a rare variant in the mannose receptor C type 2 (MRC2) gene in individuals with familial reentrant supraventricular tachycardia, a Wolff-Parkinson-White (WPW) electrocardiogram pattern, and structurally normal hearts. WPW syndrome is associated with atrial fibrillation (AF), and MRC2 was recently proposed as a protective gene for AF. We determined whether the E990G-heterozygous (het) loss-of-function variant in Mrc2 increases AF susceptibility and identified aberrant cellular mechanisms resulting from Mrc2 deficiency in atrial cardiofibroblasts (ACFs) and atrial tissue in mice that may promote AF. Programmed electrical stimulation was performed to determine AF susceptibility in Mrc2 E990G-het mice and wild-type (WT) controls. ACFs were isolated from these mice and cultured, and transcriptomic profiling by RNA sequencing and secretomic/proteomic profiling by mass spectrometry were performed on ACFs and whole atrial tissue. E990G-het mice exhibited increased susceptibility to pacing-induced AF and had decreased atrioventricular effective refractory periods compared with WT controls. Transcriptomic, secretomic, and proteomic profiling of cultured ACFs and whole atrial tissue revealed differential expression of several fibrotic regulators in E990G-het versus WT mice, including decreased ACF expression of matrix metalloproteinase 13, which degrades collagen types I, II, and III; decreased ACF expression and secretion of matrix metalloproteinase 12, which degrades collagen types I, III, IV, elastin, and fibronectin; and increased tissue levels of cellular communication network factor 2/connective tissue growth factor, a profibrotic regulator. In conclusion, Mrc2 E990G-het mice exhibit increased AF susceptibility and differentially regulated fibrotic genes and proteins.NEW & NOTEWORTHY Our study reveals a rare MRC2 gene variant (E990G) linked to familial supraventricular tachycardia and Wolff-Parkinson-White syndrome increases atrial fibrillation (AF) susceptibility in mice. The E990G-heterozygous variant disrupts atrial cardiofibroblast function, reducing protective matrix metalloproteinases (MMP-12 and MMP-13) and elevating profibrotic CCN2/CTGF levels, as shown through transcriptomic and proteomic profiling. This suggests that MRC2 deficiency promotes AF by altering fibrotic regulation in atrial tissue.

  View details for DOI 10.1152/ajpheart.00452.2025

  View details for PubMedID 40983393

  View details for PubMedCentralID PMC12643113

• Mechanisms underlying atrial fibrillation in chronic kidney disease. Journal of molecular and cellular cardiology Navarro-Garcia, J. A., Keefe, J. A., Song, J., Li, N., Wehrens, X. H. 2025; 205: 37-51

  Abstract

  Chronic kidney disease (CKD) is a serious and progressive worldwide health problem affecting 15 % of the global population. CKD is associated with higher mortality rates due to secondary complications such as cardiovascular disease. Common cardiovascular complications found in CKD patients include left ventricular hypertrophy, heart failure, and cardiac arrhythmias. The most common type of cardiac arrhythmia in CKD patients is atrial fibrillation (AF). Proper management of AF is important due to its high risk of cardiovascular complications and stroke. The incidence of AF remains higher in CKD patients than in the healthy population, highlighting the need to improve our understanding of the mechanisms underlying CKD-induced AF. In this review, we discuss well-known systemic factors linking CKD to AF pathogenesis. We highlighted the involvement of several inflammatory mediators in the CKD-induced atrial arrhythmogenesis. We also address special considerations for experimental models of CKD and AF management in CKD patients. Finally, we emphasize the need for a deeper understanding of the molecular underpinning, and for high-quality clinical investigations into the CKD-AF connection.

  View details for DOI 10.1016/j.yjmcc.2025.06.002

  View details for PubMedID 40499614

  View details for PubMedCentralID PMC12809698

• A mechanistic LNK between inflammation and atrial fibrillation? Cardiovascular research Keefe, J. A., Zhao, S., Wehrens, X. H. 2024; 120 (8): 814-816

  View details for DOI 10.1093/cvr/cvae083

  View details for PubMedID 38713542

  View details for PubMedCentralID PMC11218683

• Long-term efficacy and safety of cardiac genome editing for catecholaminergic polymorphic ventricular tachycardia. The journal of cardiovascular aging Moore, O. M., Aguilar-Sanchez, Y., Lahiri, S. K., Hulsurkar, M. M., Alberto Navarro-Garcia, J., Word, T. A., Keefe, J. A., Barazi, D., Munivez, E. M., Moore, C. T., Parthasarathy, V., Davidson, J., Lagor, W. R., Park, S. H., Bao, G., Miyake, C. Y., Wehrens, X. H. 2024; 4 (1)

  Abstract

  Heterozygous autosomal-dominant single nucleotide variants in RYR2 account for 60% of cases of catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited arrhythmia disorder associated with high mortality rates. CRISPR/Cas9-mediated genome editing is a promising therapeutic approach that can permanently cure the disease by removing the mutant RYR2 allele. However, the safety and long-term efficacy of this strategy have not been established in a relevant disease model.The purpose of this study was to assess whether adeno-associated virus type-9 (AAV9)-mediated somatic genome editing could prevent ventricular arrhythmias by removal of the mutant allele in mice that are heterozygous for Ryr2 variant p.Arg176Gln (R176Q/+).Guide RNA and SaCas9 were delivered using AAV9 vectors injected subcutaneously in 10-day-old mice. At 6 weeks after injection, R176Q/+ mice had a 100% reduction in ventricular arrhythmias compared to controls. When aged to 12 months, injected R176Q/+ mice maintained a 100% reduction in arrhythmia induction. Deep RNA sequencing revealed the formation of insertions/deletions at the target site with minimal off-target editing on the wild-type allele. Consequently, CRISPR/SaCas9 editing resulted in a 45% reduction of total Ryr2 mRNA and a 38% reduction in RyR2 protein. Genome editing was well tolerated based on serial echocardiography, revealing unaltered cardiac function and structure up to 12 months after AAV9 injection.Taken together, AAV9-mediated CRISPR/Cas9 genome editing could efficiently disrupt the mutant Ryr2 allele, preventing lethal arrhythmias while preserving normal cardiac function in the R176Q/+ mouse model of CPVT.

  View details for DOI 10.20517/jca.2023.42

  View details for PubMedID 38464671

  View details for PubMedCentralID PMC10919902

• Blocking p38γ/δ, a molecular cardiac defibrillator. Nature cardiovascular research Keefe, J. A., Wehrens, X. H. 2023; 2 (12): 1104-1106

  View details for DOI 10.1038/s44161-023-00363-2

  View details for PubMedID 39196142

  View details for PubMedCentralID 7582802

• Chronic kidney disease promotes atrial fibrillation via inflammasome pathway activation. The Journal of clinical investigation Song, J., Navarro-Garcia, J. A., Wu, J., Saljic, A., Abu-Taha, I., Li, L., Lahiri, S. K., Keefe, J. A., Aguilar-Sanchez, Y., Moore, O. M., Yuan, Y., Wang, X., Kamler, M., Mitch, W. E., Ruiz-Hurtado, G., Hu, Z., Thomas, S. S., Dobrev, D., Wehrens, X. H., Li, N. 2023; 133 (19)

  Abstract

  Chronic kidney disease (CKD) is associated with a higher risk of atrial fibrillation (AF). The mechanistic link between CKD and AF remains elusive. IL-1β, a main effector of NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation, is a key modulator of conditions associated with inflammation, such as AF and CKD. Circulating IL-1β levels were elevated in patients with CKD who had AF (versus patients with CKD in sinus rhythm). Moreover, NLRP3 activity was enhanced in atria of patients with CKD. To elucidate the role of NLRP3/IL-1β signaling in the pathogenesis of CKD-induced AF, Nlrp3-/- and WT mice were subjected to a 2-stage subtotal nephrectomy protocol to induce CKD. Four weeks after surgery, IL-1β levels in serum and atrial tissue were increased in WT CKD (WT-CKD) mice versus sham-operated WT (WT-sham) mice. The increased susceptibility to pacing-induced AF and the longer AF duration in WT-CKD mice were associated with an abbreviated atrial effective refractory period, enlarged atria, and atrial fibrosis. Genetic inhibition of NLRP3 in Nlrp3-/- mice or neutralizing anti-IL-1β antibodies effectively reduced IL-1β levels, normalized left atrial dimensions, and reduced fibrosis and the incidence of AF. These data suggest that CKD creates a substrate for AF development by activating the NLRP3 inflammasome in atria, which is associated with structural and electrical remodeling. Neutralizing IL-1β antibodies may be beneficial in preventing CKD-induced AF.

  View details for DOI 10.1172/JCI167517

  View details for PubMedID 37581942

  View details for PubMedCentralID PMC10541185

• Endothelial cell dysfunction: the culprit for cardiac denervation in aging? The journal of cardiovascular aging Moore, O. M., Keefe, J. A., Wehrens, X. H. 2023; 3 (4)

  View details for DOI 10.20517/jca.2023.36

  View details for PubMedID 38235058

  View details for PubMedCentralID PMC10793999

• Anti-Ro/SSA Antibodies in Atrioventricular Block: Innocent Bystander or Mechanistic Driver? JACC. Clinical electrophysiology Keefe, J. A., Wehrens, X. H. 2023; 9 (8 Pt 3): 1649-1651

  View details for DOI 10.1016/j.jacep.2023.04.005

  View details for PubMedID 37354190

• Mouse models of spontaneous atrial fibrillation. Mammalian genome : official journal of the International Mammalian Genome Society Keefe, J. A., Hulsurkar, M. M., Reilly, S., Wehrens, X. H. 2023; 34 (2): 298-311

  Abstract

  Atrial fibrillation (AF) is the most common arrhythmia in adults, with a prevalence increasing with age. Current clinical management of AF is focused on tertiary prevention (i.e., treating the symptoms and sequelae) rather than addressing the underlying molecular pathophysiology. Robust animal models of AF, particularly those that do not require supraphysiologic stimuli to induce AF (i.e., showing spontaneous AF), enable studies that can uncover the underlying mechanisms of AF. Several mouse models of AF have been described to exhibit spontaneous AF, but pathophysiologic drivers of AF differ among models. Here, we describe relevant AF mechanisms and provide an overview of large and small animal models of AF. We then provide an in-depth review of the spontaneous mouse models of AF, highlighting the relevant AF mechanisms for each model.

  View details for DOI 10.1007/s00335-022-09964-x

  View details for PubMedID 36173465

  View details for PubMedCentralID PMC10898345

• Cardiac function, structural, and electrical remodeling by microgravity exposure. American journal of physiology. Heart and circulatory physiology Sy, M. R., Keefe, J. A., Sutton, J. P., Wehrens, X. H. 2023; 324 (1): H1-H13

  Abstract

  Space medicine is key to the human exploration of outer space and pushes the boundaries of science, technology, and medicine. Because of harsh environmental conditions related to microgravity and other factors and hazards in outer space, astronauts and spaceflight participants face unique health and medical challenges, including those related to the heart. In this review, we summarize the literature regarding the effects of spaceflight on cardiac structure and function. We also provide an in-depth review of the literature regarding the effects of microgravity on cardiac calcium handling. Our review can inform future mechanistic and therapeutic studies and is applicable to other physiological states similar to microgravity such as prolonged horizontal bed rest and immobilization.

  View details for DOI 10.1152/ajpheart.00611.2022

  View details for PubMedID 36399385

  View details for PubMedCentralID PMC9762974

• Role of Ca2+ in healthy and pathologic cardiac function: from normal excitation-contraction coupling to mutations that cause inherited arrhythmia. Archives of toxicology Keefe, J. A., Moore, O. M., Ho, K. S., Wehrens, X. H. 2023; 97 (1): 73-92

  Abstract

  Calcium (Ca2+) ions are a key second messenger involved in the rhythmic excitation and contraction of cardiomyocytes throughout the heart. Proper function of Ca2+-handling proteins is required for healthy cardiac function, whereas disruption in any of these can cause cardiac arrhythmias. This comprehensive review provides a broad overview of the roles of Ca2+-handling proteins and their regulators in healthy cardiac function and the mechanisms by which mutations in these proteins contribute to inherited arrhythmias. Major Ca2+ channels and Ca2+-sensitive regulatory proteins involved in cardiac excitation-contraction coupling are discussed, with special emphasis on the function of the RyR2 macromolecular complex. Inherited arrhythmia disorders including catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, Brugada syndrome, short QT syndrome, and arrhythmogenic right-ventricular cardiomyopathy are discussed with particular emphasis on subtypes caused by mutations in Ca2+-handling proteins.

  View details for DOI 10.1007/s00204-022-03385-0

  View details for PubMedID 36214829

  View details for PubMedCentralID PMC10122835

• Abnormalities in cardiac and inflammatory biomarkers in ambulatory subjects after COVID-19 infection. International journal of cardiology. Heart & vasculature Keefe, J. A., Avadhanula, V., Nicholson, E. G., Devaraj, S., Piedra, P. A., Bozkurt, B., Wehrens, X. H. 2022; 43: 101144

  Abstract

  Coronavirus-2019 (COVID-19) is known to affect the heart and is associated with a pro-inflammatory state. Most studies to date have focused on clinically sick subjects. Here, we report cardiac and proinflammatory biomarkers levels in ambulatory young adults with asymptomatic or mild COVID-19 infection compared to those without infection 4-8 weeks after severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) testing.131 asymptomatic or mildly symptomatic subjects were enrolled following testing for SARS-COV-2. Fifty subjects tested negative, and 81 subjects tested positive. Serum samples were collected for measurement of C-reactive protein, ferritin, interleukin-6, NT-pro-B-type natriuretic peptide, and cardiac troponin 28-55 days after SARS-COV-2 RT-PCR testing.Biomarker levels trended higher in SARS-COV-2-positive vs negative subjects, but differences in biomarker levels or proportion of subjects with elevated biomarkers were not statistically significant with respect to SARS-COV-2 status. Among individuals with ≥ 1 comorbidity, odds of elevated CRP were greater compared to individuals without any comorbidities (odds ratio [OR] = 2.90); this effect size was increased 1.4-fold among SARS-COV-2-positive subjects (OR = 4.03). Similarly, NT-pro-BNP was associated with CVD, with the strongest association in COVID-positive individuals (OR = 16.9).In a relatively young, healthy adult population, mild COVID-19 infection was associated with mild elevations in cardiac and proinflammatory biomarkers within 4-8 weeks of mild or asymptomatic COVID-19 infection in individuals with preexisting comorbidities, but not among individuals without comorbidities. For the general population of young adults, we did not find evidence of elevation of cardiac or proinflammatory biomarkers 4-8 weeks after COVID-19 infection.Clinical Perspective: This is a characterization of cardiac and proinflammatory biomarkers in ambulatory subjects following asymptomatic or mild COVID-19 infection. Young, ambulatory individuals did not have cardiac and proinflammatory biomarker elevation 4-8 weeks after mild COVID-19 infection. However, COVID-19 infection was associated with biomarker elevations in select individuals with comorbidities.Clinical study number: H-47423.

  View details for DOI 10.1016/j.ijcha.2022.101144

  View details for PubMedID 36321063

  View details for PubMedCentralID PMC9613792

• Diagnosing atrial fibrillation: Can we do better than the ECG? Heart rhythm Ho, K. S., Keefe, J. A., Wehrens, X. H. 2022; 19 (9): 1459-1460

  View details for DOI 10.1016/j.hrthm.2022.06.007

  View details for PubMedID 35697327

  View details for PubMedCentralID PMC10077874

• Common disease-promoting signalling pathways in heart failure and atrial fibrillation: putative underlying mechanisms and potential therapeutic consequences. Cardiovascular research Keefe, J. A., Wehrens, X. H., Dobrev, D. 2022; 118 (11): 2397-2399

  View details for DOI 10.1093/cvr/cvac107

  View details for PubMedID 35788838

• In-depth characterization of a mouse model of postoperative atrial fibrillation. The journal of cardiovascular aging Keefe, J. A., Navarro-Garcia, J. A., Ni, L., Reilly, S., Dobrev, D., Wehrens, X. H. 2022; 2

  Abstract

  Postoperative atrial fibrillation (POAF), characterized as AF that arises 1-3 days after surgery, occurs after 30%-40% of cardiac and 10%-20% of non-cardiac surgeries, and is thought to arise due to transient surgery-induced triggers acting on a preexisting vulnerable atrial substrate often associated with inflammation and autonomic nervous system dysfunction. Current experimental studies often rely on human atrial tissue samples, collected during surgery prior to arrhythmia development, or animal models such as sterile pericarditis and atriotomy, which have not been robustly characterized.To characterize the demographic, electrophysiologic, and inflammatory properties of a POAF mouse model.A total of 131 wild-type C57BL/6J mice were included in this study. A total of 86 (65.6%) mice underwent cardiothoracic surgery (THOR), which consisted of bi-atrial pericardiectomy with 20 s of aortic cross-clamping; 45 (34.3%) mice underwent a sham procedure consisting of dissection down to but not into the thoracic cavity. Intracardiac pacing, performed 72 h after surgery, was used to assess AF inducibility. THOR mice showed greater AF inducibility (38.4%) compared to Sham mice (17.8%, P = 0.027). Stratifying the cohort by tertiles of age showed that the greatest risk of POAF after THOR compared to Sham occurred in the 12-19-week age group. Stratifying by sex showed that cardiothoracic (CT) surgery increased POAF risk in females but had no significant effect in males. Quantitative polymerase chain reaction of atrial samples revealed upregulation of transforming growth factor beta 1 (TGF-β1) and interleukin 6 (IL6) and 18 (IL18) expression in THOR compared to Sham mice.Here, we demonstrate that the increased POAF risk associated with CT surgery is most pronounced in female and 12-19-week-old mice, and that the expression of inflammatory cytokines is upregulated in the atria of THOR mice prone to inducible AF.

  View details for DOI 10.20517/jca.2022.21

  View details for PubMedID 36337729

  View details for PubMedCentralID PMC9632544

• An Integrative Genomic Strategy Identifies sRAGE as a Causal and Protective Biomarker of Lung Function. Chest Keefe, J., Yao, C., Hwang, S. J., Courchesne, P., Lee, G. Y., Dupuis, J., Mizgerd, J. P., O'Connor, G., Washko, G. R., Cho, M. H., Silverman, E. K., Levy, D. 2022; 161 (1): 76-84

  Abstract

  There are few clinically useful circulating biomarkers of lung function and lung disease. We hypothesized that genome-wide association studies (GWAS) of circulating proteins in conjunction with GWAS of pulmonary traits represents a clinically relevant approach to identifying causal proteins and therapeutically useful insights into mechanisms related to lung function and disease.Can an integrative genomic strategy using GWAS of plasma soluble receptor for advanced glycation end-products (sRAGE) levels in conjunction with GWAS of lung function traits identify putatively causal relations of sRAGE to lung function?Plasma sRAGE levels were measured in 6,861 Framingham Heart Study participants and GWAS of sRAGE was conducted to identify protein quantitative trait loci (pQTL), including cis-pQTL variants at the sRAGE protein-coding gene locus (AGER). We integrated sRAGE pQTL variants with variants from GWAS of lung traits. Colocalization of sRAGE pQTL variants with lung trait GWAS variants was conducted, and Mendelian randomization was performed using sRAGE cis-pQTL variants to infer causality of sRAGE for pulmonary traits. Cross-sectional and longitudinal protein-trait association analyses were conducted for sRAGE in relation to lung traits.Colocalization identified shared genetic signals for sRAGE with lung traits. Mendelian randomization analyses suggested protective causal relations of sRAGE to several pulmonary traits. Protein-trait association analyses demonstrated higher sRAGE levels to be cross-sectionally and longitudinally associated with preserved lung function.sRAGE is produced by type I alveolar cells, and it acts as a decoy receptor to block the inflammatory cascade. Our integrative genomics approach provides evidence for sRAGE as a causal and protective biomarker of lung function, and the pattern of associations is suggestive of a protective role of sRAGE against restrictive lung physiology. We speculate that targeting the AGER/sRAGE axis may be therapeutically beneficial for the treatment and prevention of inflammation-related lung disease.

  View details for DOI 10.1016/j.chest.2021.06.053

  View details for PubMedID 34237330

  View details for PubMedCentralID PMC8783029

• Integrative Genomic Analysis Reveals Four Protein Biomarkers for Platelet Traits. Circulation research Lee, D. H., Yao, C., Bhan, A., Schlaeger, T., Keefe, J., Rodriguez, B. A., Hwang, S. J., Chen, M. H., Levy, D., Johnson, A. D. 2020; 127 (9): 1182-1194

  Abstract

  Mean platelet volume (MPV) and platelet count (PLT) are platelet measures that have been linked to cardiovascular disease (CVD) and mortality risk. Identifying protein biomarkers for these measures may yield insights into CVD mechanisms.We aimed to identify causal protein biomarkers for MPV and PLT among 71 CVD-related plasma proteins measured in FHS (Framingham Heart Study) participants.We conducted integrative analyses of genetic variants associated with PLT/MPV with protein quantitative trait locus variants associated with plasma proteins followed by Mendelian randomization to infer causal relations of proteins for PLT/MPV. We also tested protein-PLT/MPV association in FHS participants. Using induced pluripotent stem cell-derived megakaryocyte clones that produce functional platelets, we conducted RNA-sequencing and analyzed expression differences between low- and high-platelet producing clones. We then performed small interfering RNA gene knockdown experiments targeting genes encoding proteins with putatively causal platelet effects in megakaryocyte clones to examine effects on platelet production. In protein-trait association analyses, ten proteins were associated with MPV and 31 with PLT. Mendelian randomization identified 4 putatively causal proteins for MPV and 4 for PLT. GP-5 (Glycoprotein V), GRN (granulin), and MCAM (melanoma cell adhesion molecule) were associated with PLT, while MPO (myeloperoxidase) showed significant association with MPV in both analyses. RNA-sequencing analysis results were directionally concordant with observed and Mendelian randomization-inferred associations for GP-5, GRN, and MCAM. In siRNA gene knockdown experiments, silencing GP-5, GRN, and MPO decreased PLTs. Genome-wide association study results suggest several of these may be linked to CVD risk.We identified 4 proteins that are causally linked to PLTs. These proteins may also have roles in the pathogenesis of CVD via a platelet/blood coagulation-based mechanism.

  View details for DOI 10.1161/CIRCRESAHA.119.316447

  View details for PubMedID 32781905

  View details for PubMedCentralID PMC8411925

• Epigenome-wide association study of DNA methylation and microRNA expression highlights novel pathways for human complex traits. Epigenetics Huan, T., Mendelson, M., Joehanes, R., Yao, C., Liu, C., Song, C., Bhattacharya, A., Rong, J., Tanriverdi, K., Keefe, J., Murabito, J. M., Courchesne, P., Larson, M. G., Freedman, J. E., Levy, D. 2020; 15 (1-2): 183-198

  Abstract

  DNA methylation (DNAm) and microRNAs (miRNAs) have been implicated in a wide-range of human diseases. While often studied in isolation, DNAm and miRNAs are not independent. We analyzed associations of expression of 283 miRNAs with DNAm at >400K CpG sites in whole blood obtained from 3565 individuals and identified 227 CpGs at which differential methylation was associated with the expression of 40 nearby miRNAs (cis-miR-eQTMs) at FDR<0.01, including 91 independent CpG sites at r2 < 0.2. cis-miR-eQTMs were enriched for CpGs in promoter and polycomb-repressed state regions, and 60% were inversely associated with miRNA expression. Bidirectional Mendelian randomization (MR) analysis further identified 58 cis-miR-eQTMCpG-miRNA pairs where DNAm changes appeared to drive miRNA expression changes and opposite directional effects were unlikely. Integration of genetic variants in joint analyses revealed an average partial between cis-miR-eQTM CpGs and miRNAs of 2% after conditioning on site-specific genetic variation, suggesting that DNAm is an important epigenetic regulator of miRNA expression. Finally, two-step MR analysis was performed to identify putatively causal CpGs driving miRNA expression in relation to human complex traits. We found that an imprinted region on 14q32 that was previously identified in relation to age at menarche is enriched with cis-miR-eQTMs. Nine CpGs and three miRNAs at this locus tested causal for age at menarche, reflecting novel epigenetic-driven molecular pathways underlying this complex trait. Our study sheds light on the joint genetic and epigenetic regulation of miRNA expression and provides insights into the relations of miRNAs to their targets and to complex phenotypes.

  View details for DOI 10.1080/15592294.2019.1640547

  View details for PubMedID 31282290

  View details for PubMedCentralID PMC6961684

• Lipidomic profiling identifies signatures of metabolic risk. EBioMedicine Yin, X., Willinger, C. M., Keefe, J., Liu, J., Fernández-Ortiz, A., Ibáñez, B., Peñalvo, J., Adourian, A., Chen, G., Corella, D., Pamplona, R., Portero-Otin, M., Jove, M., Courchesne, P., van Duijn, C. M., Fuster, V., Ordovás, J. M., Demirkan, A., Larson, M. G., Levy, D. 2020; 51: 102520

  Abstract

  Metabolic syndrome (MetS), the clustering of metabolic risk factors, is associated with cardiovascular disease risk. We sought to determine if dysregulation of the lipidome may contribute to metabolic risk factors.We measured 154 circulating lipid species in 658 participants from the Framingham Heart Study (FHS) using liquid chromatography-tandem mass spectrometry and tested for associations with obesity, dysglycemia, and dyslipidemia. Independent external validation was sought in three independent cohorts. Follow-up data from the FHS were used to test for lipid metabolites associated with longitudinal changes in metabolic risk factors.Thirty-nine lipids were associated with obesity and eight with dysglycemia in the FHS. Of 32 lipids that were available for replication for obesity and six for dyslipidemia, 28 (88%) replicated for obesity and five (83%) for dysglycemia. Four lipids were associated with longitudinal changes in body mass index and four were associated with changes in fasting blood glucose in the FHS.We identified and replicated several novel lipid biomarkers of key metabolic traits. The lipid moieties identified in this study are involved in biological pathways of metabolic risk and can be explored for prognostic and therapeutic utility.

  View details for DOI 10.1016/j.ebiom.2019.10.046

  View details for PubMedID 31877415

  View details for PubMedCentralID PMC6938899

• Genome-wide identification of DNA methylation QTLs in whole blood highlights pathways for cardiovascular disease. Nature communications Huan, T., Joehanes, R., Song, C., Peng, F., Guo, Y., Mendelson, M., Yao, C., Liu, C., Ma, J., Richard, M., Agha, G., Guan, W., Almli, L. M., Conneely, K. N., Keefe, J., Hwang, S. J., Johnson, A. D., Fornage, M., Liang, L., Levy, D. 2019; 10 (1): 4267

  Abstract

  Identifying methylation quantitative trait loci (meQTLs) and integrating them with disease-associated variants from genome-wide association studies (GWAS) may illuminate functional mechanisms underlying genetic variant-disease associations. Here, we perform GWAS of >415 thousand CpG methylation sites in whole blood from 4170 individuals and map 4.7 million cis- and 630 thousand trans-meQTL variants targeting >120 thousand CpGs. Independent replication is performed in 1347 participants from two studies. By linking cis-meQTL variants with GWAS results for cardiovascular disease (CVD) traits, we identify 92 putatively causal CpGs for CVD traits by Mendelian randomization analysis. Further integrating gene expression data reveals evidence of cis CpG-transcript pairs causally linked to CVD. In addition, we identify 22 trans-meQTL hotspots each targeting more than 30 CpGs and find that trans-meQTL hotspots appear to act in cis on expression of nearby transcriptional regulatory genes. Our findings provide a powerful meQTL resource and shed light on DNA methylation involvement in human diseases.

  View details for DOI 10.1038/s41467-019-12228-z

  View details for PubMedID 31537805

  View details for PubMedCentralID PMC6753136

• Evidence for a Causal Role of the SH2B3-β2M Axis in Blood Pressure Regulation. Hypertension (Dallas, Tex. : 1979) Keefe, J. A., Hwang, S. J., Huan, T., Mendelson, M., Yao, C., Courchesne, P., Saleh, M. A., Madhur, M. S., Levy, D. 2019; 73 (2): 497-503

  Abstract

  Genetic variants at SH2B3 are associated with blood pressure and circulating β2M (β-2 microglobulin), a well-characterized kidney filtration biomarker. We hypothesize that circulating β2M is an independent risk predictor of hypertension and may causally contribute to its development. The study sample consisted of 7 065 Framingham Heart Study participants with measurements of plasma β2M. Generalized estimating equations were used to test the association of β2M with prevalent and new-onset hypertension. There were 2 145 (30%) cases of prevalent hypertension at baseline and 886 (21%) cases of incident hypertension during 6 years of follow-up. A 1-SD increase in baseline plasma β2M was associated with a greater risk of prevalent (odds ratio 1.14, 95% CI 1.05-1.24) and new-onset (odds ratio 1.18, 95% CI 1.07-1.32) hypertension. Individuals within the top β2M quartile had a greater risk than the bottom quartile for prevalent (odds ratio 1.29, 95% CI 1.05-1.57) and new-onset (odds ratio 1.59, 95% CI 1.20-2.11) hypertension. These associations remained essentially unchanged in analyses restricted to participants free of albuminuria and chronic kidney disease. Mendelian randomization demonstrated that lower SH2B3 expression is causal for increased circulating β2M levels, and in a hypertensive mouse model, knockout of Sh2b3 increased β 2 M gene expression. In a community-based study of healthy individuals, higher plasma β2M levels are associated with increased risk of prevalent and incident hypertension independent of chronic kidney disease status. Overlapping genetic signals for hypertension and β2M, in conjunction with mouse knockout experiments, suggest that the SH2B3-β2M axis plays a causal role in hypertension.

  View details for DOI 10.1161/HYPERTENSIONAHA.118.12094

  View details for PubMedID 30624993

  View details for PubMedCentralID PMC6334659

• Genome-wide mapping of plasma protein QTLs identifies putatively causal genes and pathways for cardiovascular disease. Nature communications Yao, C., Chen, G., Song, C., Keefe, J., Mendelson, M., Huan, T., Sun, B. B., Laser, A., Maranville, J. C., Wu, H., Ho, J. E., Courchesne, P., Lyass, A., Larson, M. G., Gieger, C., Graumann, J., Johnson, A. D., Danesh, J., Runz, H., Hwang, S. J., Liu, C., Butterworth, A. S., Suhre, K., Levy, D. 2018; 9 (1): 3268

  Abstract

  Identifying genetic variants associated with circulating protein concentrations (protein quantitative trait loci; pQTLs) and integrating them with variants from genome-wide association studies (GWAS) may illuminate the proteome's causal role in disease and bridge a knowledge gap regarding SNP-disease associations. We provide the results of GWAS of 71 high-value cardiovascular disease proteins in 6861 Framingham Heart Study participants and independent external replication. We report the mapping of over 16,000 pQTL variants and their functional relevance. We provide an integrated plasma protein-QTL database. Thirteen proteins harbor pQTL variants that match coronary disease-risk variants from GWAS or test causal for coronary disease by Mendelian randomization. Eight of these proteins predict new-onset cardiovascular disease events in Framingham participants. We demonstrate that identifying pQTLs, integrating them with GWAS results, employing Mendelian randomization, and prospectively testing protein-trait associations holds potential for elucidating causal genes, proteins, and pathways for cardiovascular disease and may identify targets for its prevention and treatment.

  View details for DOI 10.1038/s41467-018-05512-x

  View details for PubMedID 30111768

  View details for PubMedCentralID PMC6093935

• Multigenerational memory and adaptive adhesion in early bacterial biofilm communities. Proceedings of the National Academy of Sciences of the United States of America Lee, C. K., de Anda, J., Baker, A. E., Bennett, R. R., Luo, Y., Lee, E. Y., Keefe, J. A., Helali, J. S., Ma, J., Zhao, K., Golestanian, R., O'Toole, G. A., Wong, G. C. 2018; 115 (17): 4471-4476

  Abstract

  Using multigenerational, single-cell tracking we explore the earliest events of biofilm formation by Pseudomonas aeruginosa During initial stages of surface engagement (≤20 h), the surface cell population of this microbe comprises overwhelmingly cells that attach poorly (∼95% stay <30 s, well below the ∼1-h division time) with little increase in surface population. If we harvest cells previously exposed to a surface and direct them to a virgin surface, we find that these surface-exposed cells and their descendants attach strongly and then rapidly increase the surface cell population. This "adaptive," time-delayed adhesion requires determinants we showed previously are critical for surface sensing: type IV pili (TFP) and cAMP signaling via the Pil-Chp-TFP system. We show that these surface-adapted cells exhibit damped, coupled out-of-phase oscillations of intracellular cAMP levels and associated TFP activity that persist for multiple generations, whereas surface-naïve cells show uncorrelated cAMP and TFP activity. These correlated cAMP-TFP oscillations, which effectively impart intergenerational memory to cells in a lineage, can be understood in terms of a Turing stochastic model based on the Pil-Chp-TFP framework. Importantly, these cAMP-TFP oscillations create a state characterized by a suppression of TFP motility coordinated across entire lineages and lead to a drastic increase in the number of surface-associated cells with near-zero translational motion. The appearance of this surface-adapted state, which can serve to define the historical classification of "irreversibly attached" cells, correlates with family tree architectures that facilitate exponential increases in surface cell populations necessary for biofilm formation.

  View details for DOI 10.1073/pnas.1720071115

  View details for PubMedID 29559526

  View details for PubMedCentralID PMC5924909