Faculty Bibliography

Aging is one of the hottest topics in biomedical research. Advances in research and medicine have helped to preserve human health, leading to an extension of life expectancy. However, the extension of life is an irreversible process that is accompanied by the development of aging-related conditions such as weakness, slower metabolism, and stiffness of vessels. It also debated that aging can be considered an actual disease with aging-derived comorbidities, including cancer or cardiovascular disease. Currently, cardiovascular disorders, including atherosclerosis, are considered as premature aging and represent the first causes of death in developed countries, accounting for 31% of annual deaths globally. Emerging evidence has identified hypoxia-inducible factor-1α as a critical transcription factor with an essential role in aging-related pathology, in particular, regulating cellular senescence associated with cardiovascular aging. In this review, we will focus on the regulation of senescence mediated by hypoxia-inducible factor-1α in age-related pathologies, with particular emphasis on the crosstalk between endothelial and vascular cells in age-associated atherosclerotic lesions. More specifically, we will focus on the characteristics and mechanisms by which cells within the vascular wall, including endothelial and vascular cells, achieve a senescent phenotype.

BACKGROUND:The current trends of unhealthy lifestyle behaviors in underserved communities are disturbing. Thus, effective health promotion strategies constitute an unmet need. OBJECTIVE:To assess the impact of two different lifestyle interventions on parents/caregivers of children attending preschools in a socioeconomically disadvantaged community. METHODS:The FAMILIA study is a cluster-randomized trial involving 15 Head Start preschools in Harlem, New York. Schools, and their children's parents/caregivers, were randomized to receive either an "individual-focused" or "peer-to-peer based" lifestyle intervention program for 12 months or control. The primary outcome was the change from baseline to 12 months in a composite health score related to Blood pressure, Exercise, Weight, Alimentation and Tobacco (Fuster-BEWAT Score, FBS), ranging from 0 to 15 (ideal health=15). To assess the sustainability of the intervention, we evaluated the change of FBS at 24 months. Main pre-specified secondary outcomes included changes in FBS subcomponents and the impact of the knowledge of presence of atherosclerosis as assessed by bilateral carotid/femoral vascular ultrasound. Mixed-effects models were used to test for intervention effects. RESULTS:We enrolled 635 parents/caregivers with a mean age of 38±11 years, 83% female, 57% Hispanic/Latino and 31% African American, and a baseline FBS of 9.3±2.4 points. The mean within-group change in FBS from baseline to 12 months was ∼0.20 points in all groups, with no overall between-group differences. However, high-adherence participants to the intervention exhibited a greater change in FBS than their low-adherence counterparts: 0.30 points (95% CI: 0.03 to 0.57; p-value = 0.025) vs. 0.00 points (95% CI: -0.43 to 0.43; p-value = 1.0), respectively. Furthermore, the knowledge by the participant of the presence of atherosclerosis significantly boosted the intervention effects. Similar results were sustained at 24 months. CONCLUSIONS:Although we did not observe overall significant differences between intervention and control groups, the FAMILIA trial highlights that high adherence rates to lifestyle interventions may improve health outcomes. It also suggests a potential contributory role of the presentation of atherosclerosis pictures, providing helpful information to improve future lifestyle interventions in adults.

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Atherosclerosis is driven by multifaceted contributions of the immune system within the circulation and at vascular focal sites. However, specific characteristics of dysregulated immune cells within atherosclerotic lesions that lead to clinical events such as ischemic stroke or myocardial infarction are poorly understood. Here, using single-cell proteomic and transcriptomic analyses, we uncovered distinct features of both T cells and macrophages in carotid artery plaques of patients with clinically symptomatic disease (recent stroke or transient ischemic attack) compared to asymptomatic disease (no recent stroke). Plaques from symptomatic patients were characterized by a distinct subset of CD4⁺ T cells and by T cells that were activated and differentiated. Moreover, some T cell subsets in these plaques presented markers of T cell exhaustion. Additionally, macrophages from these plaques contained alternatively activated phenotypes, including subsets associated with plaque vulnerability. In plaques from asymptomatic patients, T cells and macrophages were activated and displayed evidence of interleukin-1β signaling. The identification of specific features of innate and adaptive immune cells in plaques that are associated with cerebrovascular events may enable the design of more precisely tailored cardiovascular immunotherapies.

BACKGROUND:Genetic loss-of-function variants (LoFs) associated with disease traits are increasingly recognized as critical evidence for the selection of therapeutic targets. We integrated the analysis of genetic and clinical data from 10,511 individuals in the Mount Sinai BioMe Biobank to identify genes with loss-of-function variants (LoFs) significantly associated with cardiovascular disease (CVD) traits, and used RNA-sequence data of seven metabolic and vascular tissues isolated from 600 CVD patients in the Stockholm-Tartu Atherosclerosis Reverse Network Engineering Task (STARNET) study for validation. We also carried out in vitro functional studies of several candidate genes, and in vivo studies of one gene. RESULTS:We identified LoFs in 433 genes significantly associated with at least one of 10 major CVD traits. Next, we used RNA-sequence data from the STARNET study to validate 115 of the 433 LoF harboring-genes in that their expression levels were concordantly associated with corresponding CVD traits. Together with the documented hepatic lipid-lowering gene, APOC3, the expression levels of six additional liver LoF-genes were positively associated with levels of plasma lipids in STARNET. Candidate LoF-genes were subjected to gene silencing in HepG2 cells with marked overall effects on cellular LDLR, levels of triglycerides and on secreted APOB100 and PCSK9. In addition, we identified novel LoFs in DGAT2 associated with lower plasma cholesterol and glucose levels in BioMe that were also confirmed in STARNET, and showed a selective DGAT2-inhibitor in C57BL/6 mice not only significantly lowered fasting glucose levels but also affected body weight. CONCLUSION:In sum, by integrating genetic and electronic medical record data, and leveraging one of the world's largest human RNA-sequence datasets (STARNET), we identified known and novel CVD-trait related genes that may serve as targets for CVD therapeutics and as such merit further investigation.

BACKGROUND:Genetic variants currently known to affect coronary artery disease (CAD) risk explain less than one-quarter of disease heritability. The heritability contribution of gene regulatory networks (GRNs) in CAD, which are modulated by both genetic and environmental factors, is unknown. OBJECTIVES:This study sought to determine the heritability contributions of single nucleotide polymorphisms affecting gene expression (eSNPs) in GRNs causally linked to CAD. METHODS:Seven vascular and metabolic tissues collected in 2 independent genetics-of-gene-expression studies of patients with CAD were used to identify eSNPs and to infer coexpression networks. To construct GRNs with causal relations to CAD, the prior information of eSNPs in the coexpression networks was used in a Bayesian algorithm. Narrow-sense CAD heritability conferred by the GRNs was calculated from individual-level genotype data from 9 European genome-wide association studies (GWAS) (13,612 cases, 13,758 control cases). RESULTS:The authors identified and replicated 28 independent GRNs active in CAD. The genetic variation in these networks contributed to 10.0% of CAD heritability beyond the 22% attributable to risk loci identified by GWAS. GRNs in the atherosclerotic arterial wall (n = 7) and subcutaneous or visceral abdominal fat (n = 9) were most strongly implicated, jointly explaining 8.2% of CAD heritability. In all, these 28 GRNs (each contributing to >0.2% of CAD heritability) comprised 24 to 841 genes, whereof 1 to 28 genes had strong regulatory effects (key disease drivers) and harbored many relevant functions previously associated with CAD. The gene activity in these 28 GRNs also displayed strong associations with genetic and phenotypic cardiometabolic disease variations both in humans and mice, indicative of their pivotal roles as mediators of gene-environmental interactions in CAD. CONCLUSIONS:GRNs capture a major portion of genetic variance and contribute to heritability beyond that of genetic loci currently known to affect CAD risk. These networks provide a framework to identify novel risk genes/pathways and study molecular interactions within and across disease-relevant tissues leading to CAD.

BACKGROUND:Antiretroviral therapy (ART) for HIV infection increases risk for coronary artery disease (CAD), presumably by causing dyslipidemia and increased atherosclerosis. We applied systems pharmacology to identify and validate specific regulatory gene networks through which ART drugs may promote CAD. METHODS:Transcriptional responses of human cell lines to 15 ART drugs retrieved from the Library of Integrated Cellular Signatures (overall 1127 experiments) were used to establish consensus ART gene/transcriptional signatures. Next, enrichments of differentially expressed genes and gene-gene connectivity within these ART-consensus signatures were sought in 30 regulatory gene networks associated with CAD and CAD-related phenotypes in the Stockholm Atherosclerosis Gene Expression study. RESULTS:Ten of 15 ART signatures were significantly enriched both for differential expression and connectivity in a specific atherosclerotic arterial wall regulatory gene network (AR-RGN) causal for CAD involving RNA processing genes. An atherosclerosis in vitro model of cholestryl ester-loaded foam cells was then used for experimental validation. Treatments of these foam cells with ritonavir, nelfinavir, and saquinavir at least doubled cholestryl ester accumulation ( P=0.02, 0.0009, and 0.02, respectively), whereas RNA silencing of the AR-RGN top key driver, PQBP1 (polyglutamine binding protein 1), significantly curbed cholestryl ester accumulation following treatment with any of these ART drugs by >37% ( P<0.05). CONCLUSIONS:By applying a novel systems pharmacology data analysis framework, 3 commonly used ARTs (ritonavir, nelfinavir, and saquinavir) were found altering the activity of AR-RGN, a regulatory gene network promoting foam cell formation and risk of CAD. Targeting AR-RGN or its top key driver PQBP1 may help reduce CAD side effects of these ART drugs.

Whereas a healthy endothelium maintains physiological vascular functions, endothelial damage contributes to the development of cardiovascular diseases. Endothelial senescence is the main determinant of endothelial dysfunction and thus of age-related cardiovascular disease. The objective of this study is to test the involvement of microRNA-126 and HIF-1α in a model of replicative endothelial senescence and the interrelationship between both molecules in this in vitro model. We demonstrated that senescent endothelial cells experience impaired tube formation and delayed wound healing. Senescent endothelial cells failed to express HIF-1α, and the microvesicles released by these cells failed to carry HIF-1α. Of note, HIF-1α protein levels were restored in HIF-1α stabilizer-treated senescent endothelial cells. Finally, we show that microRNA-126 was downregulated in senescent endothelial cells and microvesicles. With regard to the interplay between microRNA-126 and HIF-1α, transfection with a microRNA-126 inhibitor downregulated HIF-1α expression in early passage endothelial cells. Moreover, while HIF-1α inhibition reduced tube formation and wound healing closure, microRNA-126 levels remained unchanged. These data indicate that HIF-1α is a target of miRNA-126 in protective and reparative functions, and suggest that their therapeutic modulation could benefit age-related vascular disease.