Search

Evidence from nonhuman animal models demonstrates an important role for immune cells in hypertension, but immune cell changes in human hypertension are less clear. Using mass cytometry, we demonstrate novel and selective reductions in CCR10(+) regulatory T cells (Tregs) and PD-1(+)CD57(−)CD8(+) memory T cells. RNA sequencing reveals that CCR10(+) Tregs exhibit gene expression changes consistent with enhanced immunosuppressive function. In addition, CITE-Seq demonstrates that PD-1(+)CD57(−)CD8(+) memory T cells exhibit features of T-cell exhaustion. Taken together, these results provide novel evidence for decreases in anti-inflammatory and/or hypofunctional T-cell populations that may contribute to enhanced inflammation in human hypertension.

SH2B3 (SH2B adaptor protein 3) is an adaptor protein that negatively regulates cytokine signaling and cell proliferation. A common missense single nucleotide polymorphism inWe used CRISPR-Cas9 technology to create mice homozygous for the major (Arg/Arg) and minor (Trp/Trp) alleles of thisTrp/Trp mice exhibit 10 mmHg higher systolic BP during chronic Ang II infusion compared to Arg/Arg controls. Renal injury and perivascular fibrosis are exacerbated in Trp/Trp mice compared to Arg/Arg controls following Ang II infusion. Renal and ex vivo stimulated splenic CD8Taken together, these results suggest that the Trp encoding allele of rs3184504 is causal for BP elevation and renal dysfunction, in part through loss of SH2B3-mediated repression of T cell IL-12 signaling leading to enhanced IFNg production.

Background: SH2B3 (SH2B adaptor protein 3) is an adaptor protein that negatively regulates cytokine signaling and cell proliferation. A common missense single nucleotide polymorphism in SH2B3 (rs3184504) results in substitution of tryptophan (Trp) for arginine (Arg) at amino acid 262 and is a top association signal for hypertension in human genome-wide association studies. Whether this variant is causal for hypertension, and if so, the mechanism by which it impacts pathogenesis is unknown. Methods: We used CRISPR-Cas9 technology to create mice homozygous for the major (Arg/Arg) and minor (Trp/Trp) alleles of this SH2B3 polymorphism. Mice underwent angiotensin II (Ang II) infusion to evaluate differences in blood pressure (BP) elevation and end-organ damage including albuminuria and renal fibrosis. Cytokine production and Stat4 phosphorylation was also assessed in Arg/Arg and Trp/Trp T cells. Results: Trp/Trp mice exhibit 10 mmHg higher systolic BP during chronic Ang II infusion compared to Arg/Arg controls. Renal injury and perivascular fibrosis are exacerbated in Trp/Trp mice compared to Arg/Arg controls following Ang II infusion. Renal and ex vivo stimulated splenic CD8 + T cells from Ang II-infused Trp/Trp mice produce significantly more interferon gamma (IFNg) compared to Arg/Arg controls. Interleukin-12 (IL-12)-induced IFNg production is greater in Trp/Trp compared to Arg/Arg CD8 + T cells. In addition, IL-12 enhances Stat4 phosphorylation to a greater degree in Trp/Trp compared to Arg/Arg CD8 + T cells, suggesting that Trp-encoding SH2B3 exhibits less negative regulation of IL-12 signaling to promote IFNg production. Finally, we demonstrated that a multi-SNP model genetically predicting increased SH2B3 expression in lymphocytes is inversely associated with hypertension and hypertensive chronic kidney disease in humans.. Conclusions: Taken together, these results suggest that the Trp encoding allele of rs3184504 is causal for BP elevation and renal dysfunction, in part through loss of SH2B3-mediated repression of T cell IL-12 signaling leading to enhanced IFNg production.

Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome where patients, despite having a normal left ventricular systolic function, present with symptoms of volume overload. Recent data have shown that HFpEF is associated with elevation of inflammatory biomarkers. In a well-known rodent hypertensive model (DOCA-salt), we isolated CD45+ leukocytes from the heart and then performed CITE-Seq, a novel technique to obtain transcriptomic and surface marker expression on single cells, on a total of 4,359 and 7,600 cells from four sham and four DOCA-salt left ventricles, respectively. Analysis showed significant differential gene expression in the myeloid (macrophage/monocytic) population. We then took the top 20 genes that were differentially expressed between DOCA-salt vs sham treated myeloid cells and performed a genetic analysis called PrediXcan in Vanderbilt’s DNA databank, BioVU. Our analysis used gene expression prediction models built from the GTEx Project and tested its association with the HFpEF phenotype, which was derived on ICD-9 and 10 codes and natural language programming. From BioVU, 88,660 subjects were included in the association analysis. Of the 20 genes, 8 did not meet prediction model criteria for PrediXcan. In the remaining 12 genes, genetically predicted expression of only 2 ( Lgals1 and Ctsl ) are associated with a HFpEF phenotype. Of these, the gene encoding galectin 1, Lgals1 , had the lowest p-value (0.02) and highest beta coefficient (0.32) corresponding to an odds ratio for HFpEF of 1.38. Galectin-1 is a well known mediator of inflammation resolution in infection and tumor biology, however its role in heart failure is unknown. We are currently exploring the role of galectin-1 in the pathophysiology of HFpEF through Lgals1 -/- and LysM-Cre x Lgals1 fl/fl mice. In conclusion, using two different approaches in mice and humans, we identified galectin-1 as a new potential mediator in HFpEF development.

Aims Elevated serum immunoglobulins have been associated with experimental and human hypertension for decades but whether immunoglobulins and B cells play a causal role in hypertension pathology is unclear. In this study, we sought to determine the role of B cells and high-affinity class-switched immunoglobulins on hypertension and hypertensive end-organ damage to determine if they might represent viable therapeutic targets for this disease. Methods and results We purified serum IgG from mice exposed to vehicle or angiotensin (Ang) II to induce hypertension and adoptively transferred these to wild type (WT) recipient mice receiving a subpressor dose of Ang II. We found that transfer of IgG from hypertensive animals leads does not affect blood pressure, endothelial function, renal inflammation, albuminuria, or T cell derived cytokine production compared with transfer of IgG from vehicle infused animals. As an alternative approach to investigate the role of high affinity, class-switched immunoglobulins, we studied mice with genetic deletion of activation-induced deaminase (Aicda-/-). These mice have elevated levels of IgM but virtual absence of class-switched immunoglobulins such as IgG subclasses and IgA. Neither male nor female Aicda-/- mice were protected from Ang II-induced hypertension and renal/vascular damage. To determine if IgM or non-immunoglobulin dependent innate functions of B cells play a role in hypertension, we studied mice with severe global B cell deficiency due to deletion of the membrane exon of the IgM heavy chain (μMT-/-). μMT-/- mice were also not protected from hypertension or end-organ damage induced by Ang II infusion or deoxycorticosterone acetate (DOCA)-salt treatment. Conclusions These results suggest that B cells and serum immunoglobulins do not play a causal role in hypertension pathology. Translational perspective Our results suggest that in most cases of essential hypertension, B cells are not a causal factor in the pathophysiology of disease. Thus, elevated serum immunoglobulins seen in hypertensive animals and humans may reflect a biomarker of aberrant immune activation in hypertension and not a therapeutic target. However, autoantibodies may cause hypertension in special cases, and more work is needed to determine whether specific B cell subsets might play an important role that is masked by global B cell deficiency.

Rationale: There is an intimate relationship between the endothelium and monocytes, and activated endothelial cells promote monocyte transformation to macrophages and dendritic cells (DCs). Recently, a subset of human DCs expressing the receptor tyrosine kinase, Axl and the lectin siglec-6 has been described and termed (AS) DCs. Objective: We sought to determine if circulating AS DCs are increased in human hypertension and to examine how Axl signaling contributes to this disease. Methods and Results: We demonstrated that circulating AS DCs are increased in hypertensive humans compared with normotensive controls. Pulse pressure in humans also correlated with plasma levels of the Axl agonist GAS6 (growth arrest specific 6). Exposure of human endothelial cells to 10% cyclical stretch increased release of the GAS6, promoted Axl signaling and caused AS DC formation; events that were inhibited by blockade of Axl with R428 or by siRNA knockdown of either endothelial GAS6 or Axl. GAS6/Axl signaling in human monocytes potentiated interleukin 1β production through NLRP3 (nucleotide-binding oligomerization domain, leucine rich tepeat and pyrin domain containing protein)/caspase-1 and caused accumulation of immunogenic isoLG (isolevuglandin)-protein adducts. In mice, the Axl inhibitor R428 or global deletion of Axl attenuated hypertension and renal inflammation caused by Ang II (angiotensin II) infusion. Bone marrow transplant studies demonstrated a role of both stromal and immunologic Axl in Ang II–induced hypertension. Lastly, in freshly harvested human endothelial cells, a striking correlation was observed between the degree of endothelial cell activation as reflected by ICAM-1 (intracellular adhesion molecule 1), isoLG-adduct accumulation, and intracellular GAS6 levels. Conclusions: We define a previously unrecognized interaction of human endothelial cells and monocytes that promote formation of AS DCs in hypertension and show a critical role of GAS6 and Axl signaling in both immune cells and endothelial cells. This pathway is potentially a novel therapeutic target to reduce inflammation and end organ damage in hypertension.

Interleukin-33 (IL-33) is an alarmin critical for alternative macrophage activation and has been linked to hypertension in humans. The goal of this study was to evaluate whether IL-33 contributes to (deoxycorticosterone acetate) DOCA-salt induced cardiac remodeling and macrophage polarization. C57Bl/6J (WT, n=8) and IL33-deficient (IL-33 KO, n=8) mice underwent uninephrectomy, implantation of a DOCA pellet, and 1% NaCl supplementation of drinking water for three weeks. A control group of WT mice (n=10) underwent a sham procedure and were maintained on normal water. Systolic blood pressure measured by tail cuff showed a significant increase in WT DOCA-salt mice (128±9 mmHg; mean±SD) and IL-33 KO DOCA-salt mice (129±11) compared to WT sham (103±11). Hypertension was accompanied by significantly increased heart to body weight ratios in WT DOCA-salt (7.0±1.0 mg/g) and IL-33 KO DOCA-salt (6.8±0.6) compared to WT sham (5.3±0.3) mice. Glomerular injury was assessed by urine albumin-to-creatinine ratios, which were similarly increased in WT DOCA-salt (0.92±0.4) and IL-33 KO DOCA-salt (0.42±0.09) mice compared to WT controls (0.03±0.003). Echocardiography was performed to assess left ventricle (LV) dimensions and systolic function. IL-33 KO DOCA-salt mice exhibited a significantly higher cardiac output (22±2 mL/min) compared to WT sham (16±3) and WT DOCA-salt (15±3) mice, driven by increased stroke volume. No significant changes in heart rate or ejection fraction were observed between groups. Additionally, IL33-KO DOCA-salt mice had an increased diastolic LV internal dimension (3.2±0.2 mm) compared to WT sham (2.7±0.3) and WT DOCA-salt (2.7±0.3). DOCA-salt induced increased mRNA expression of alternative macrophage activation markers in both LV ( Chil3, Il10) and isolated peritoneal macrophages ( Arg1, Retnla, Tgfb1 ). Peritoneal macrophages deficient in IL-33 expressed less Il10 compared to WT. Cardiac fibrosis evaluated by Masson’s trichrome showed a significant increase in LV collagen deposition in WT DOCA-salt mice (1.09±0.8% trichrome positive) compared to WT sham (0.43±0.3) but no increase in IL-33 KO DOCA-salt mice (0.54±0.3). In conclusion, IL-33 deficiency alters macrophage and cardiac function in the DOCA-salt model of hypertension.

Circadian rhythms govern our daily physiological processes. However, disruption of circadian rhythms, as can occur with ad libitum Western diets, disrupt these processes leading to cardiometabolic diseases. Our lab and others have shown that Th17 cells, which produce interleukin 17A (IL-17A), are implicated in the development of cardiovascular and renal end-organ damage associated with high fat and/or high salt diets. Th17 cell differentiation and trafficking is regulated by the circadian clock and influenced by light-dark cycles. However, whether feeding-fasting rhythms influence Th17 cell responses is poorly understood. We tested the hypothesis that limiting food intake to the 12-hr active period (time-restricted feeding, TRF) mitigates high fat and high salt (HF/HS) diet induced T cell IL-17A production and target organ damage. Beginning at 8 weeks of age, male C57Bl/6J mice were placed on either a normal chow/normal salt (NC/NS) or a HF/HS diet for 20 weeks, with TRF intervention occurring during the last two weeks in the HF/HS + TRF group. Body weight was similarly significantly increased in the HF/HS and HF/HS + TRF groups in comparison to the NC/NS group. Th17 cells were significantly increased (2.6-fold increase, p = 0.02) in the Peyer’s patches (lymphoid aggregates found in the small intestines) of mice on HF/HS diet in comparison to those on NC/NS. Importantly, TRF abolished this increase. Renal CD4 + T cell IL-17A production, as measured by flow cytometry, was increased by HF/HS diet compared to NC/NS (3-fold increase, p = 0.02). Similarly, TRF abolished this increase. This study highlights how Western diets exacerbate intestinal and renal IL-17A production and the potential beneficial impact of a behavioral intervention, TRF, to mitigate the Th17 mediated inflammation associated with diet-induced obesity.

Emerging evidence from animal models has demonstrated the importance of multiple innate and adaptive immune cells in hypertension. We hypothesized that the abundance and phenotype of circulating immune cell subsets are altered in human hypertension. To test this, we performed high dimensional single cell profiling of human peripheral blood mononuclear cells using mass cytometry. Unsupervised computational analysis revealed a 40% decrease in CD8 + memory T cells in hypertensive individuals. Using Phenograph to identify subsets of these cells revealed a selective 60% decrease in PD-1 + CD8 + memory T cells in hypertension. This observation was confirmed in a validation cohort using flow cytometry in which PD-1 + CD8 + memory T cells were significantly decreased 44% in hypertensive compared to control individuals. To determine the phenotype of these PD-1 + CD8 + memory T cells, we performed Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-Seq) on four control and four hypertensive individuals. Using antibodies to identify PD-1 + and PD-1 - CD8 + memory T cells, gene set enrichment analysis of the coordinate single cell transcriptomic data revealed that PD-1 + cells exhibit over-representation of features of both immunologically active effector T cells and hypofunctional exhausted T cells. Thus, clustering analysis of PD-1 + CD8 + memory T cells was performed which demonstrated 4 distinct subclusters. One of these subclusters was decreased in hypertension and exhibited selective expression of multiple inhibitory receptors characteristic of exhausted T cells. At the protein level, this subcluster was marked by expression of the inhibitory receptor LAG3 and low levels of CD57. Combining these markers to identify PD-1 + LAG3 + CD57 - CD8 + memory T cells permitted identification of exhausted cells which demonstrated a significant 35% decrease in hypertensive compared to control individuals using flow cytometry. Taken together, these results demonstrate novel and reproducible decreases in circulating PD-1 + CD8 + memory T cells with features of exhaustion in human hypertension. These findings provide new insights into the pathogenesis of human hypertension including loss and/or re-invigoration of exhausted T cells.

Endothelial cells (ECs) activated by hypertensive (10%) cyclical stretch releases factors including IL-6 and hydrogen peroxide that stimulate the conversion of human monocytes to an intermediate inflammatory phenotype. A novel subset of DCs in humans has been identified that express Axl and Sigelc-6 + (AS DCs) which drive T cells proliferation and produce inflammatory cytokines. The interplay between ECs and AS DCs in hypertension is unkown. We assessed AS DCs by flow cytometry in normotensive (n=23) and hypertensive (n=11) subjects and found a significant increase in AS DCs in hypertensive compared to normotensive subjects (297 ± 73 vs. 108 ± 26/ml; p =0.0304). When moncoytes were exposed to human aortic endothelial cells (HAECs) undergoing 10% stretch, the formation of AS DCs was markedly enhanced compared to 5%. The ligand for Axl is growth arrest specific 6 (GAS6), and we found that 10% HAEC stretch caused a 50% increase in the release of GAS6 by ECs comapred to 5%. We knocked down either EC GAS6 or Axl using siRNA and either of these abrogated the ability of ECs to promote AS DC formation. Using flow cytometry to analyze venous ECs that had been harvested from 23 volunteers to quantify EC activation and GAS6 secretion in vivo, we found a positive association between GAS6 and ICAM-1 (R 2 =0.39, p =0.0012). We found a positive association between pulse pressure and plasma GAS6 (R 2 =0.25, p =0.0079) ands systolic blood pressure and GAS6 (R 2 =0.19, p=0.0025) in volunteers. We found that plasma GAS6 is increased in Ang II hypertension and that either genetic deletion or pharmacological inhibition of Axl lowered blood pressure in reposne to Ang II and reduced renal inflammation. To investigate the role of immunological vs. stromal Axl in vivo, we perfomed bone marrow transplant studies and found that both Axl WT/WT ->Axl -/- and Axl -/- ->Axl W/WT had a significant reduction in blood pressure by 20 mmHg compared to the Axl WT/WT -> Axl WT/WT control. These data show that both immunological and stromal Axl contribute to hypertension and inflammation and GAS6/Axl signlaing may be a novel therapeutic target in this disease.

Justification: Hypertension and systemic lupus erythematosus (SLE) share similarities including elevations of blood pressure, proteinuria, inflammation and renal dysfunction and both involve formation of isoLG adducts. We hypothesized that isoLG scavenging would modulate overlapping gene pathways in inflammatory cells in these two conditions. Methods: We performed 10 X genomics single cell sequencing on splenocytes of C57Bl/6 mice with angiotensin II (Ang II)-induced hypertension, Ang II co-treatment with the isoLG scavenger 2HOBA, and 24-week-old B6.SLE123 mice with or without 6-weeks of 2HOBA. Matched C57Bl/6 females were used as controls for the B6.SLE123 mice. Results: Both models exhibited myeloid expansion and genes associated with neutrophil infiltration compared to their respective controls and 2HOBA attenuated this ( Table 1 ). Hypertension was associated with neutrophil expansion whereas SLE was associated an expansion of neutrophils, monocytes, and dendritic cells. In SLE, 2HOBA predominantly modulated gene expression in dendritic cells. Gene ontology revealed 2HOBA downregulated genes governing inflammation including Il1 β (Avglog2(fold change) = -1.6, P adj = 0.002) in both hypertension and SLE. Conclusions: In a mouse model of SLE, scavenging of isoLGs with 2HOBA downregulates inflammatory genes specifically in DCs. In models of both hypertension and SLE, scavenging of isoLG prevents neutrophil expansion. Combined these data describe a shared role of isoLGs in hypertension and SLE and suggest a specific role of DCs and neutrophil activation in the pathogenesis of both conditions. Table 1. Percentage of myeloid derived cells in all groups.

Background: Metabolic remodeling precedes most alterations during cardiac hypertrophic growth under hemodynamic stress. The elevation of glucose utilization has been recognized as a hallmark of metabolic remodeling. However, its role in cardiac hypertrophic growth and heart failure in response to pressure overload remains to be fully illustrated. Here, we aimed to dissect the role of cardiac PKM1 (pyruvate kinase muscle isozyme 1) in glucose metabolic regulation and cardiac response under pressure overload. Methods: Cardiac-specific deletion of PKM1 was achieved by crossing the floxed PKM1 mouse model with the cardiomyocyte-specific Cre transgenic mouse. PKM1 transgenic mice were generated under the control of tetracycline response elements, and cardiac-specific overexpression of PKM1 was induced by doxycycline administration in adult mice. Pressure overload was triggered by transverse aortic constriction. Primary neonatal rat ventricular myocytes were used to dissect molecular mechanisms. Moreover, metabolomics and nuclear magnetic resonance spectroscopy analyses were conducted to determine cardiac metabolic flux in response to pressure overload. Results: We found that PKM1 expression is reduced in failing human and mouse hearts. It is important to note that cardiomyocyte-specific deletion of PKM1 exacerbates cardiac dysfunction and fibrosis in response to pressure overload. Inducible overexpression of PKM1 in cardiomyocytes protects the heart against transverse aortic constriction–induced cardiomyopathy and heart failure. At the mechanistic level, PKM1 is required for the augmentation of glycolytic flux, mitochondrial respiration, and ATP production under pressure overload. Furthermore, deficiency of PKM1 causes a defect in cardiomyocyte growth and a decrease in pyruvate dehydrogenase complex activity at both in vitro and in vivo levels. Conclusions: These findings suggest that PKM1 plays an essential role in maintaining a homeostatic response in the heart under hemodynamic stress.

Elevated cardiovascular risk including stroke, heart failure, and heart attack is present even after normalization of blood pressure in patients with hypertension. Underlying immune cell activation is a likely culprit. Although immune cells are important for protection against invading pathogens, their chronic overactivation may lead to tissue damage and high blood pressure. Triggers that may initiate immune activation include viral infections, autoimmunity, and lifestyle factors such as excess dietary salt. These conditions activate the immune system either directly or through their impact on the gut microbiome, which ultimately produces chronic inflammation and hypertension. T cells are central to the immune responses contributing to hypertension. They are activated in part by binding specific antigens that are presented in major histocompatibility complex molecules on professional antigen-presenting cells, and they generate repertoires of rearranged T-cell receptors. Activated T cells infiltrate tissues and produce cytokines including interleukin 17A, which promote renal and vascular dysfunction and end-organ damage leading to hypertension. In this comprehensive review, we highlight environmental, genetic, and microbial associated mechanisms contributing to both innate and adaptive immune cell activation leading to hypertension. Targeting the underlying chronic immune cell activation in hypertension has the potential to mitigate the excess cardiovascular risk associated with this common and deadly disease.

Introduction: Inflammation and oxidative stress are linked to multiple risk factors for atrial fibrillation (AF), and to AF itself in the setting of sterile injury (e.g. after catheter ablation or cardiac surgery). However, anti-inflammatory therapies and conventional antioxidants cause adverse effects or are ineffective to prevent AF. Highly reactive mediators of lipid peroxidation such as isolevuglandins (IsoLGs) have been identified as a major component of oxidative stress-related injury. We hypothesized that during AF promoted by cardiac inflammation, a scavenger of IsoLG will decrease AF susceptibility. Methods: We studied mice with a systemic inflammatory phenotype due to deficiency in the lymphocyte adaptor protein ( Lnk -/- ), a negative regulator of cytokine signaling. At weaning, Lnk -/- mice and their wild-type (WT) littermates received either vehicle or a potent IsoLG scavenger, 2-hydroxybenzylamine (2-HOBA), by oral administration. At age 14 weeks, animals underwent transesophageal burst pacing, echocardiography, and tissue harvest or flow cytometry to measure atrial inflammation and IsoLG-adducts. Results: Cardiac histology and echocardiography revealed no major histologic or structural abnormalities in Lnk -/- mice. Nevertheless, Lnk -/- mice demonstrated a significant increase in AF burden compared to WT controls (124.8±43.3 vs 6.8±3 sec, respectively [mean±SEM, n=28, 12; P 30 sec; 48.1% vs 0%; P-/- mice, with a significant increase in CD3, CD19, NK1.1, and CD11b/MHCII positive cells, compared to atria from WT control mice. Furthermore, there was a 2 to 4-fold increase in IsoLG-adducts for Lnk -/- atrial immune cells positive for CD3, CD19, NK1.1 and CD11b/MHCII, compared to cells from WT atria. Lnk -/- mice treated with 2-HOBA had significantly reduced AF burden (4.7±4.5 sec, n=7; P Conclusions: IsoLGs play a critical role in the pathogenesis of inflammation-mediated AF, and 2-HOBA, a scavenger of IsoLGs, represents a potentially novel therapeutic strategy for AF in this clinical setting.

SH2B3, also known as LNK, is an adaptor protein that negatively regulates growth factor and cytokine signaling. The minor allele of a single nucleotide polymorphism in SH2B3 (rs3184504) encodes a tryptophan (Trp) at amino acid 262 as opposed to arginine (Arg) and is strongly associated with hypertension in genome-wide association studies. Whether this variant is causal and how it impacts hypertension development and end-organ damage is unknown. We used CRISPR-Cas9 to engineer mice homozygous for the major and minor alleles of this SH2B3 polymorphism, resulting in Arg/Arg and Trp/Trp mice, respectively. Trp/Trp mice exhibited increased systolic blood pressure (SBP) by radiotelemetry during weeks 3-4 of angiotensin II (Ang II) infusion compared to Arg/Arg mice (nighttime SBP 168 vs 158 mm Hg, respectively). Renal dysfunction was also exacerbated in Ang II-treated Trp/Trp compared to Arg/Arg mice, as evidenced by significantly increased urinary albumin/creatinine ratio (0.41 vs 0.17), renal perivascular fibrosis (fibrosis score 2.0 vs 1.0), and renal macrophages (8,341 vs 6,413 per kidney). In addition, renal CD8 + T cells from Ang II-treated Trp/Trp mice produced significantly more IFNγ compared to Arg/Arg controls (median fluorescence intensity 20,455 vs 14,134), and ex vivo stimulated splenic CD8 + T cells from Trp/Trp compared to Arg/Arg mice made 2.7-fold more IFNγ. To determine a mechanism for increased T cell IFNγ production, dendritic cells and naïve T cells from Trp/Trp and Arg/Arg mice were co-cultured in different combinations. The greatest increase in GM-CSF-induced IFNγ production occurred when both dendritic cells and T cells came from Trp/Trp mice (3.4-fold greater than both cell types from Arg/Arg mice). This effect appears to be due to loss of SH2B3-mediated suppression of GM-CSF signaling, as overexpression of Trp-encoding SH2B3 in HEK cells exhibited significantly less repression of GM-CSF-induced Stat5 activation compared to Arg-encoding SH2B3. Taken together, these findings suggest that the Trp encoding allele of rs3184504 is a causal variant promoting blood pressure elevation and renal dysfunction, at least in part through loss of SH2B3-mediated repression of T cell IFNγ production.

Deoxycorticosterone acetate (DOCA)-salt is a common hypertension model in mice and has recently been used to study heart failure with preserved ejection fraction (HFpEF) in rats. Our goal was to validate DOCA-salt as a mouse model of HFpEF and determine how DOCA-salt alters the cardiac immunological landscape to identify novel therapeutic targets for this disease. DOCA-salt mice underwent uninephrectomy, implantion of a DOCA pellet, and supplementation of the drinking water with 1% NaCl water for three weeks. Control mice underwent a sham procedure and received normal water. Compared to control mice, DOCA-salt mice exhibited elevated systolic BP, increased heart weight to body weight ratios (5.6 vs 7.1), increased lung wet to dry weight ratios (4.4 vs 4.8) indicative of pulmonary congestion, and decreased time to exhaustion upon treadmill exercise testing (23.0 vs. 18.5 seconds). On conscious echocardiography, DOCA-salt mice exhibited a preserved ejection fraction. Invasive hemodynamic studies revealed an increased tau constant (5.7 vs 8.2) and increased end-diastolic pressures in DOCA-salt mice (1.7 vs 2.6), consistent with diastolic dysfunction. CITE-seq, a novel technique to obtain transcriptomic and surface marker expression on single cells, was performed on a total of 4,359 and 7,600 cells sorted live CD45+ leukocytes from four sham and four DOCA-salt left ventricles, respectively. Unsupervised computational analysis revealed 29 clusters of immune cells. Six clusters containing natural killer, T lymphocyte and myeloid cell populations were overrepresented and five B cell clusters were underrepresented in DOCA-salt samples. Differential expression analysis of CD11b+CD64+ cardiac macrophages revealed transcriptional changes between groups with 146 significantly upregulated and 111 downregulated genes. Gene set enrichment analysis showed upregulation of leukocyte migration, response to type I interferon, and cytokine-mediated signaling pathways in DOCA-salt macrophages. In conclusion, the DOCA-salt mouse model recapitulates key features of HFpEF including diastolic dysfunction with preserved ejection fraction, cardiac hypertrophy, and pulmonary congestion and is associated with an altered cardiac immune cell profile.

We have shown that dendritic cells (DCs) from hypertensive mice convey hypertension when adoptively transferred to recipients. Recently a novel subset of DCs in humans that express Axl and Sigelc-6 + (AS DCs) have been identified which drive T cell proliferation and produce IL-1β, IL-6 and IL-23, consistent with DCs we have observed in hypertension. We hypothesized that AS cells are increased in hypertension and contribute to immune activation in this disease. We quantified circulating AS DCs by flow cytometry in normotensive (n=23) and hypertensive (n=11) subjects and found a more than 2-fold increase in circulating AS DCs in hypertensive compared to normotensive subjects (297 ± 73 vs. 108 ± 26/ml; p =0.0304). To investigate the mechanism by which AS DCs are formed in hypertension, we co-cultured human aortic endothelial cells (HAECs) undergoing either normotensive (5%) or hypertensive (10%) cyclical stretch for 48 hours with CD14 + monocytes from normotensive donors. Co-culture of monocytes with HAECs exposed to 10% stretch significantly increased AS DCs and AS DC IL-1β production when compared to 5% stretch alone as assessed by flow cytometry (21 ± 5 vs. 131 ± 32 IL-1β + AS DCs). Moreover, inhibition of Axl signaling with R248, completely abolished the production of IL-1β in AS DCs (34 ± 8 IL-1β + AS DCs). In additional experiments we found that 10% stretch caused a 50% increase in release of growth arrest 6 (GAS6), the ligand for Axl, from HAECs compared to 5% stretch. Treatment of human monocytes with GAS6 mimicked the effect of 10% stretch in promoting AS cell formation and IL-1β production. Based on the increased secretion of GAS6 from HAECs, we used a J-wire to harvest human endothelial cells from 23 additional volunteers to assess endothelial cell activation and GAS6 secretion in vivo. We found a positive association between pulse pressure and plasma GAS6 (R 2 =0.25, p =0.0079) and a striking positive association between GAS6 and ICAM-1 (R 2 =0.39, p =0.0012). These data show that secretion of GAS6 by an activated endothelial seems to promote the formation and activation of AS DCs. Thus, the interplay between endothelial-derived GAS6 and AS DCs seem to be an important mechanism in human hypertension and might be a novel therapeutic target for this disease.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is the cause of the global pandemic of coronavirus disease‐2019 (COVID‐19). SARS‐CoV‐2 is a zoonotic disease, but little is known about variations in species susceptibility that could identify potential reservoir species, animal models, and the risk to pets, wildlife, and livestock. Certain species, such as domestic cats and tigers, are susceptible to SARS‐CoV‐2 infection, while other species such as mice and chickens are not. Most animal species, including those in close contact with humans, have unknown susceptibility. Hence, methods to predict the infection risk of animal species are urgently needed. SARS‐CoV‐2 spike protein binding to angiotensin‐converting enzyme 2 (ACE2) is critical for viral cell entry and infection. Here we integrate species differences in susceptibility with multiple in‐depth structural analyses to identify key ACE2 amino acid positions including 30, 83, 90, 322, and 354 that distinguish susceptible from resistant species. Using differences in these residues across species, we developed a susceptibility score that predicts an elevated risk of SARS‐CoV‐2 infection for multiple species including horses and camels. We also demonstrate that SARS‐CoV‐2 is nearly optimal for binding ACE2 of humans compared to other animals, which may underlie the highly contagious transmissibility of this virus among humans. Taken together, our findings define potential ACE2 and SARS‐CoV‐2 residues for therapeutic targeting and identification of animal species on which to focus research and protection measures for environmental and public health.

In only a few months, the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic, leaving physicians, scientists, and public health officials racing to understand, treat, and contain this zoonotic disease. SARS-CoV-2 has made the leap from animals to humans, but little is known about variations in species susceptibility that could identify potential reservoir species, animal models, and the risk to pets, wildlife, and livestock. While there is evidence that certain species, such as cats, are susceptible, the vast majority of animal species, including those in close contact with humans, have unknown susceptibility. Hence, methods to predict their infection risk are urgently needed. SARS-CoV-2 spike protein binding to angiotensin converting enzyme 2 (ACE2) is critical for viral cell entry and infection. Here we identified key ACE2 residues that distinguish susceptible from resistant species using in-depth sequence and structural analyses of ACE2 and its binding to SARS-CoV-2. Our findings have important implications for identification of ACE2 and SARS-CoV-2 residues for therapeutic targeting and identification of animal species with increased susceptibility for infection on which to focus research and protection measures for environmental and public health.

We describe a mechanism responsible for systemic lupus erythematosus (SLE). In humans with SLE and in 2 SLE murine models, there was marked enrichment of isolevuglandin-adducted proteins (isoLG adducts) in monocytes and dendritic cells. We found that antibodies formed against isoLG adducts in both SLE-prone mice and humans with SLE. In addition, isoLG ligation of the transcription factor PU.1 at a critical DNA binding site markedly reduced transcription of all C1q subunits. Treatment of SLE-prone mice with the specific isoLG scavenger 2-hydroxybenzylamine (2-HOBA) ameliorated parameters of autoimmunity, including plasma cell expansion, circulating IgG levels, and anti-dsDNA antibody titers. 2-HOBA also lowered blood pressure, attenuated renal injury, and reduced inflammatory gene expression uniquely in C1q-expressing dendritic cells. Thus, isoLG adducts play an essential role in the genesis and maintenance of systemic autoimmunity and hypertension in SLE.

We and others have demonstrated that interleukin-17A (IL-17A) plays a critical role in the pathogenesis of cardiovascular disease and hypertension. Patients with psoriasis, an IL-17A mediated autoimmune disease, are at elevated risk for cardiovascular events. New biologic therapies for psoriasis have been developed that target IL-17A (secukinumab) or its receptor (brodalumab), but their impact on incident hypertension and its associated complications is unknown and remain unexplored outside of short-term safety in clinical trials. Our goal is to perform a retrospective case-control study utilizing the Synthetic Derivative (Vanderbilt’s de-identified version of the electronic health record) to determine whether incident hypertension or other major adverse cardiovascular events is reduced in patients with psoriasis receiving IL-17A targeted therapies versus other therapeutics. Patients are defined as cases by 2 or more mentions of a psoriasis ICD9 or ICD10 code and at least one documented prescription for secukinumab or brodalumab. Controls are defined by the presence of 2 or more psoriasis ICD codes, no documented exposure to the drugs of interest, and a mention of “psoriasis” in their Problem List. Using these definitions, we identified 571 cases and 4484 controls in the Synthetic Derivative. Of the 571 potential cases identified, 65 were confirmed by manual review for an initial validation study. Of the manually confirmed cases, 22 (34%) were male and 43 (66%) were female. Manually reviewed cases had a mean record length of 5.0 years with an average of 29.9 discrete ICD mentions. Twenty-three cases (35%) had an ICD code for hypertension, which predated the first documented psoriasis code in eight patients. Thus, we are able to use the Synthetic Derivative to identify patients with psoriasis receiving biologic therapies and assess temporal relationships relevant to hypertension. We plan to expand this study to the larger cohort identified and analyze rates of hypertension and a composite outcome of hypertension complications, including stroke, myocardial infarction, heart failure, and chronic kidney disease, in cases and controls matched for age, gender, race, and BMI.

T and B cells have been implicated in hypertension, but the mechanisms by which they produce a coordinated response is unknown. T follicular helper (Tfh) cells that produce interleukin 21 (IL21) promote germinal center (GC) B cell responses leading to immunoglobulin (Ig) production. Here we investigate the role of IL21 and Tfh cells in hypertension. In response to angiotensin (Ang) II-induced hypertension, T cell IL21 production is increased, and Il21-/- mice develop blunted hypertension, attenuated vascular end-organ damage, and decreased interleukin 17A (IL17A) and interferon gamma production. Tfh-like cells and GC B cells accumulate in the aorta and plasma IgG1 is increased in hypertensive WT but not Il21-/-mice. Furthermore, Tfh cell deficient mice develop blunted hypertension and vascular hypertrophy in response to Ang II infusion. Importantly, IL21 neutralization reduces blood pressure (BP) and reverses endothelial dysfunction and vascular inflammation. Moreover, recombinant IL21 impairs endothelium-dependent relaxation ex vivo and decreases nitric oxide production from cultured endothelial cells. Finally, we show in humans that peripheral blood T cell production of IL21 correlates with systolic BP and IL17A production. These data suggest that IL21 may be a novel therapeutic target for the treatment of hypertension and its micro- and macrovascular complications.