Examining sociodemographic correlates of opioid use, misuse, and use disorders in the All of Us Research Program

BACKGROUND

The All of Us Research Program enrolls diverse US participants which provide a unique opportunity to better understand the problem of opioid use. This study aims to estimate the prevalence of opioid use and its association with sociodemographic characteristics from survey data and electronic health record (EHR).

METHODS

A total of 214,206 participants were included in this study who competed survey modules and shared EHR data. Adjusted logistic regressions were used to explore the associations between sociodemographic characteristics and opioid use.

RESULTS

The lifetime prevalence of street opioids was 4%, and the nonmedical use of prescription opioids was 9%. Men had higher odds of lifetime opioid use (aOR: 1.4 to 3.1) but reduced odds of current nonmedical use of prescription opioids (aOR: 0.6). Participants from other racial and ethnic groups were at reduced odds of lifetime use (aOR: 0.2 to 0.9) but increased odds of current use (aOR: 1.9 to 9.9) compared with non-Hispanic White participants. Foreign-born participants were at reduced risks of opioid use and diagnosed with opioid use disorders (OUD) compared with US-born participants (aOR: 0.36 to 0.67). Men, Younger, White, and US-born participants are more likely to have OUD.

CONCLUSIONS

All of Us research data can be used as an indicator of national trends for monitoring the prevalence of receiving prescription opioids, diagnosis of OUD, and non-medical use of opioids in the US. The program employs a longitudinal design for routinely collecting health-related data including EHR data, that will contribute to the literature by providing important clinical information related to opioids over time. Additionally, this data will enhance the estimates of the prevalence of OUD among diverse populations, including groups that are underrepresented in the national survey data.

Achieving a Representative Sample of Asian Americans in Biomedical Research Through Community-Based Approaches: Comparing Demographic Data in the All of Us Research Program With the American Community Survey

BACKGROUND

Underrepresented persons are often not included in biomedical research. It is unknown if the general Asian American population is being represented in All of Us. The purpose of this study was to compare the Asian demographic data in the All of Us cohort with the Asian nationally representative data from the American Community Survey.

METHOD

Demographic characteristics and health literacy of Asians in All of Us were examined. Findings were qualitatively compared with the Asian data in the 2019 American Community Survey 1-year estimate.

RESULTS

Compared with the national composition of Asians, less All of Us participants were born outside the United States (64% vs 79%), were younger, and had higher levels of education (76% vs 52%). Over 60% of All of Us participants reported high levels of health literacy.

CONCLUSION

This study had implications for the development of strategies that ensure diverse populations are represented in biomedical research.

Investigation of hypertension and type 2 diabetes as risk factors for dementia in the All of Us cohort

The World Health Organization recently defined hypertension and type 2 diabetes (T2D) as modifiable comorbidities leading to dementia and Alzheimer's disease. In the United States (US), hypertension and T2D are health disparities, with higher prevalence seen for Black and Hispanic minority groups compared to the majority White population. We hypothesized that elevated prevalence of hypertension and T2D risk factors in Black and Hispanic groups may be associated with dementia disparities. We interrogated this hypothesis using a cross-sectional analysis of participant data from the All of Us (AoU) Research Program, a large observational cohort study of US residents. The specific objectives of our study were: (1) to compare the prevalence of dementia, hypertension, and T2D in the AoU cohort to previously reported prevalence values for the US population, (2) to investigate the association of hypertension, T2D, and race/ethnicity with dementia, and (3) to investigate whether race/ethnicity modify the association of hypertension and T2D with dementia. AoU participants were recruited from 2018 to 2019 as part of the initial project cohort (R2019Q4R3). Participants aged 40-80 with electronic health records and demographic data (age, sex, race, and ethnicity) were included for analysis, yielding a final cohort of 125,637 individuals. AoU participants show similar prevalence of hypertension (32.1%) and T2D (13.9%) compared to the US population (32.0% and 10.5%, respectively); however, the prevalence of dementia for AoU participants (0.44%) is an order of magnitude lower than seen for the US population (5%). AoU participants with dementia show a higher prevalence of hypertension (81.6% vs. 31.9%) and T2D (45.9% vs. 11.4%) compared to non-dementia participants. Dominance analysis of a multivariable logistic regression model with dementia as the outcome shows that hypertension, age, and T2D have the strongest associations with dementia. Hispanic was the only race/ethnicity group that showed a significant association with dementia, and the association of sex with dementia was non-significant. The association of T2D with dementia is likely explained by concurrent hypertension, since > 90% of participants with T2D also had hypertension. Black race and Hispanic ethnicity interact with hypertension, but not T2D, to increase the odds of dementia. This study underscores the utility of the AoU participant cohort to study disease prevalence and risk factors. We do notice a lower participation of aged minorities and participants with dementia, revealing an opportunity for targeted engagement. Our results indicate that targeting hypertension should be a priority for risk factor modifications to reduce dementia incidence.

The All of Us Research Program: Data quality, utility, and diversity

The All of Us Research Program seeks to engage at least one million diverse participants to advance precision medicine and improve human health. We describe here the cloud-based Researcher Workbench that uses a data passport model to democratize access to analytical tools and participant information including survey, physical measurement, and electronic health record (EHR) data. We also present validation study findings for several common complex diseases to demonstrate use of this novel platform in 315,000 participants, 78% of whom are from groups historically underrepresented in biomedical research, including 49% self-reporting non-White races. Replication findings include medication usage pattern differences by race in depression and type 2 diabetes, validation of known cancer associations with smoking, and calculation of cardiovascular risk scores by reported race effects. The cloud-based Researcher Workbench represents an important advance in enabling secure access for a broad range of researchers to this large resource and analytical tools.

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The All of Us Research Program has released data for over 315,000 participants

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Demonstration projects support the utility and validity of the All of Us dataset

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The cloud-based Researcher Workbench provides secure, low-cost compute power

The engagement of participants in the research process and broad availability of data to diverse researchers are essential elements in building precision medicine equitably available for all. The NIH has established the ambitious All of Us Research Program to build one of the most diverse health databases in history with tools to support research to improve human health. Here, we present the initial launch of the Researcher Workbench with data types including surveys, physical measurements, and electronic health record data with validation studies to support researcher use of this novel platform. Broad access for researchers to data like these is a critical step in returning value to participants seeking to support the advancement of precision medicine and improved health for all.

Geographic Variation in Obesity at the State Level in the All of Us Research Program

INTRODUCTION

National obesity prevention strategies may benefit from precision health approaches involving diverse participants in population health studies. We used cohort data from the National Institutes of Health All of Us Research Program (All of Us) Researcher Workbench to estimate population-level obesity prevalence.

METHODS

To estimate state-level obesity prevalence we used data from physical measurements made during All of Us enrollment visits and data from participant electronic health records (EHRs) where available. Prevalence estimates were calculated and mapped by state for 2 categories of body mass index (BMI) (kg/m2): obesity (BMI >30) and severe obesity (BMI >35). We calculated and mapped prevalence by state, excluding states with fewer than 100 All of Us participants.

RESULTS

Data on height and weight were available for 244,504 All of Us participants from 33 states, and corresponding EHR data were available for 88,840 of these participants. The median and IQR of BMI taken from physical measurements data was 28.4 (24.4- 33.7) and 28.5 (24.5-33.6) from EHR data, where available. Overall obesity prevalence based on physical measurements data was 41.5% (95% CI, 41.3%-41.7%); prevalence of severe obesity was 20.7% (95% CI, 20.6-20.9), with large geographic variations observed across states. Prevalence estimates from states with greater numbers of All of Us participants were more similar to national population-based estimates than states with fewer participants.

CONCLUSION

All of Us participants had a high prevalence of obesity, with state-level geographic variation mirroring national trends. The diversity among All of Us participants may support future investigations on obesity prevention and treatment in diverse populations.

Growth Arrest Specific-6 and Axl Coordinate Inflammation and Hypertension

[Figure: see text].

Predictive Analytics for Glaucoma Using Data From the All of Us Research Program

PURPOSE

To (1) use All of Us (AoU) data to validate a previously published single-center model predicting the need for surgery among individuals with glaucoma, (2) train new models using AoU data, and (3) share insights regarding this novel data source for ophthalmic research.

DESIGN

Development and evaluation of machine learning models.

METHODS

Electronic health record data were extracted from AoU for 1,231 adults diagnosed with primary open-angle glaucoma. The single-center model was applied to AoU data for external validation. AoU data were then used to train new models for predicting the need for glaucoma surgery using multivariable logistic regression, artificial neural networks, and random forests. Five-fold cross-validation was performed. Model performance was evaluated based on area under the receiver operating characteristic curve (AUC), accuracy, precision, and recall.

RESULTS

The mean (standard deviation) age of the AoU cohort was 69.1 (10.5) years, with 57.3% women and 33.5% black, significantly exceeding representation in the single-center cohort (P = .04 and P < .001, respectively). Of 1,231 participants, 286 (23.2%) needed glaucoma surgery. When applying the single-center model to AoU data, accuracy was 0.69 and AUC was only 0.49. Using AoU data to train new models resulted in superior performance: AUCs ranged from 0.80 (logistic regression) to 0.99 (random forests).

CONCLUSIONS

Models trained with national AoU data achieved superior performance compared with using single-center data. Although AoU does not currently include ophthalmic imaging, it offers several strengths over similar big-data sources such as claims data. AoU is a promising new data source for ophthalmic research.

Sodium activates human monocytes via the NADPH oxidase and isolevuglandin formation

AIMS

Prior studies have focused on the role of the kidney and vasculature in salt-induced modulation of blood pressure; however, recent data indicate that sodium accumulates in tissues and can activate immune cells. We sought to examine mechanisms by which salt causes activation of human monocytes both in vivo and in vitro.

METHODS AND RESULTS

To study the effect of salt in human monocytes, monocytes were isolated from volunteers to perform several in vitro experiments. Exposure of human monocytes to elevated Na+ex vivo caused a co-ordinated response involving isolevuglandin (IsoLG)-adduct formation, acquisition of a dendritic cell (DC)-like morphology, expression of activation markers CD83 and CD16, and increased production of pro-inflammatory cytokines tumour necrosis factor-α, interleukin (IL)-6, and IL-1β. High salt also caused a marked change in monocyte gene expression as detected by RNA sequencing and enhanced monocyte migration to the chemokine CC motif chemokine ligand 5. NADPH-oxidase inhibition attenuated monocyte activation and IsoLG-adduct formation. The increase in IsoLG-adducts correlated with risk factors including body mass index, pulse pressure. Monocytes exposed to high salt stimulated IL-17A production from autologous CD4+ and CD8+ T cells. In addition, to evaluate the effect of salt in vivo, monocytes and T cells isolated from humans were adoptively transferred to immunodeficient NSG mice. Salt feeding of humanized mice caused monocyte-dependent activation of human T cells reflected by proliferation and accumulation of T cells in the bone marrow. Moreover, we performed a cross-sectional study in 70 prehypertensive subjects. Blood was collected for flow cytometric analysis and 23Na magnetic resonance imaging was performed for tissue sodium measurements. Monocytes from humans with high skin Na+ exhibited increased IsoLG-adduct accumulation and CD83 expression.

CONCLUSION

Human monocytes exhibit co-ordinated increases in parameters of activation, conversion to a DC-like phenotype and ability to activate T cells upon both in vitro and in vivo sodium exposure. The ability of monocytes to be activated by sodium is related to in vivo cardiovascular disease risk factors. We therefore propose that in addition to the kidney and vasculature, immune cells like monocytes convey salt-induced cardiovascular risk in humans.

Highly Reactive Isolevuglandins Promote Atrial Fibrillation Caused by Hypertension

Oxidative damage is implicated in atrial fibrillation (AF), but antioxidants are ineffective therapeutically. The authors tested the hypothesis that highly reactive lipid dicarbonyl metabolites, or isolevuglandins (IsoLGs), are principal drivers of AF during hypertension. In a hypertensive murine model and stretched atriomyocytes, the dicarbonyl scavenger 2-hydroxybenzylamine (2-HOBA) prevented IsoLG adducts and preamyloid oligomers (PAOs), and AF susceptibility, whereas the ineffective analog 4-hydroxybenzylamine (4-HOBA) had minimal effect. Natriuretic peptides generated cytotoxic oligomers, a process accelerated by IsoLGs, contributing to atrial PAO formation. These findings support the concept of pre-emptively scavenging reactive downstream oxidative stress mediators as a potential therapeutic approach to prevent AF.

Abstract P160: Hypertension is Associated With Monocytes Activation in the Blood in Mice and Humans

Monocytes play a crucial role in immune activation and the development of hypertension. Deletion of monocytes prevents experimental hypertension, and monocyte derived dendritic cells (DCs) and macrophages promote T cell activation and tissue damage. Our group recently found that monocytes exposed to hypertensive mechanical stretch convert to a pro-inflammatory phenotype denoted by expression CD14 + CD16 + , also known as intermediate monocytes. We aimed to determine whether hypertension has a direct effect on the bone marrow to activate the production and mobilization of monocytes. To study this, we initially analyzed the circulating monocytes from 15 normotensive and 12 hypertensive subjects using flow cytometry and found that hypertensive subjects have an absolute monocytosis compared to normotensives (1014 ± 113 vs. 567.5 ± 97 per uL, p < 0.05). This is associated with high numbers in both the classical CD14 + CD16 - monocytes and the non-classical CD14 low CD16 + monocytes. To further study mechanisms involved, we analyzed monocytes in the blood and bone marrow from C57BL/6 mice following two weeks of sham or Ang II infusion (490 ng/kg/min, s.c.). Similar to the findings in humans, more total monocytes were found in mice with Ang II-induced hypertension (46.7±10.1 vs 18.7±4.7 per μL, p<0.05). Ang II also induced an increase in Ly6C high expressing monocytes (Ang II: 34.1±65.6 vs. Sham: 12.3±3.5 per μL, p<0.05), reflecting activation. We also observed an increase in Ly6C high expressing monocytes in the bone marrow. Taken together, our results suggest that hypertension is associated with monocytosis in humans and mice, and this is likely due to increased BM production. This increase in monocytes may prime the immune system for activation and increased tissue inflammation. Moreover, the level of circulating monocytes might prove to be a useful biomarker of inflammation in hypertension.

Hypertension and increased endothelial mechanical stretch promote monocyte differentiation and activation: roles of STAT3, interleukin 6 and hydrogen peroxide

Aims

Monocytes play an important role in hypertension. Circulating monocytes in humans exist as classical, intermediate, and non-classical forms. Monocyte differentiation can be influenced by the endothelium, which in turn is activated in hypertension by mechanical stretch. We sought to examine the role of increased endothelial stretch and hypertension on monocyte phenotype and function.

Methods and results

Human monocytes were cultured with confluent human aortic endothelial cells undergoing either 5% or 10% cyclical stretch. We also characterized circulating monocytes in normotensive and hypertensive humans. In addition, we quantified accumulation of activated monocytes and monocyte-derived cells in aortas and kidneys of mice with Angiotensin II-induced hypertension. Increased endothelial stretch enhanced monocyte conversion to CD14++CD16+ intermediate monocytes and monocytes bearing the CD209 marker and markedly stimulated monocyte mRNA expression of interleukin (IL)-6, IL-1β, IL-23, chemokine (C-C motif) ligand 4, and tumour necrosis factor α. STAT3 in monocytes was activated by increased endothelial stretch. Inhibition of STAT3, neutralization of IL-6 and scavenging of hydrogen peroxide prevented formation of intermediate monocytes in response to increased endothelial stretch. We also found evidence that nitric oxide (NO) inhibits formation of intermediate monocytes and STAT3 activation. In vivo studies demonstrated that humans with hypertension have increased intermediate and non-classical monocytes and that intermediate monocytes demonstrate evidence of STAT3 activation. Mice with experimental hypertension exhibit increased aortic and renal infiltration of monocytes, dendritic cells, and macrophages with activated STAT3.

Conclusions

These findings provide insight into how monocytes are activated by the vascular endothelium during hypertension. This is likely in part due to a loss of NO signalling and increased release of IL-6 and hydrogen peroxide by the dysfunctional endothelium and a parallel increase in STAT activation in adjacent monocytes. Interventions to enhance bioavailable NO, reduce IL-6 or hydrogen peroxide production or to inhibit STAT3 may have anti-inflammatory roles in hypertension and related conditions.

Abstract 088: The Immune Mechanisms of Salt-Sensitivity

Salt-sensitivity is present in 50% of all hypertensive individuals. Prior studies have focused on the roles of kidney, vasculature and sympathetic activity in salt-sensitivity but the contribution of immune cells is poorly understood. We recently found that in murine dendritic cells amiloride sensitive channels sense salt and trigger NADPH oxidase-dependent formation of isolevuglandin-(IsolG)-adducts. We tested the hypothesis that human monocytes exhibit salt-sensitivity leading to activation via IsoLG-adduct formation and this is associated with cardiovascular risk factors. In a cohort of 18 subjects, we found that the sodium intake, measured by 24 hours urine excretion (UNa) was positively correlated with plasma levels of IsolGs. We also measured accumulation of interstitial sodium in 70 subjects by Magnetic Sodium Resonance and evaluated their circulating monocytes by flow cytometry. Subjects with high skin sodium had higher levels of IsoLGs in their monocytes (24±6 vs 38±6 %, p<0.05) and higher expression of CD83, an activation and dendritic cell marker (0.04 ± 0.009 vs 0.12± 0.04%, p =0.04). To investigate the ability of monocytes to respond to salt, we cultured monocytes from 17 subjects in high salt environment (HS:190 mM NaCl) or normal media (NS:150mM NaCl) for 48 hours. In culture, 47% of the subjects respond to salt, denoted by an increase of at least 20% in IsoLG formation (NS: 1327±240 vs. HS: 2217±653, p =0.009) as well as increased expression of the activation markers CD83 and CD86. The subjects’ cardiovascular risk factors including pulse pressure, BMI, glucose and total cholesterol positively correlated with the amount of IsolGs produced (ΔHS-NS) in response to salt (r=0.51 p<0.05, r=0.66 p=0.005, r=0.55 p<0.05, p=0.72 p=0.003, respectively). Interestingly, 5 pM of Ouabain, a Na-K-ATPase blocker, increased intracellular sodium and expression of CD86 (NS: 98±11, HS: 203 ±16 vs, NS+ Ouabain: 476 ± 58 MFI, p=0.001) and CD83 (NS: 778±90, HS: 1529 ± 94 vs, NS+ Ouabain: 1649 ± 209 MFI, p=0.003). We suggest that in addition to the kidney and vasculature, human monocytes and monocyte derived cells exhibit salt sensitivity, and that this is conveyed by cardiovascular risk factors and activity of the Na-K-ATPase.

Abstract 127: Axl + Siglec6 + Dendritic Cells: the Role of Salt, Stretch, and Hypertension

We have shown that monocyte-derived dendritic cells (DCs) are activated in hypertension to produce large amounts of cytokines and to activate T cells. DCs from hypertensive mice can convey hypertension when adoptively transferred to recipients. Single cell sequencing has recently identified a novel subset of DCs in humans that express Axl and Sigelc6 + (AS DCs). These cells have been reported to potently drive T cell proliferation and to produce large amounts of IL-8 and IL12. The role of AS DCs in hypertension remains unknown. We isolated total peripheral blood mononuclear cells (PBMCs) from normotensive (n=23) and hypertensive (n=12) patients and assessed DC populations, including AS DCs, using flow cytometry. We found a significant increase in the AS DCs in hypertensive compared to normotensive patients (297 ± 73 vs. 108 ± 26/ml; P=0.0304). In contrast, there were no differences in CD1c + DCs (3398 ± 776 vs. 5245 ± 122/ml) or CD141 + DCs (164 ± 20 vs. 218 ± 49/ml) between normotensive and hypertensive subjects. To investigate the mechanism by which AS DCs are formed in hypertension, we used two in vitro hypertensive stimuli: exposure to salt and hypertensive stretch of adjacent human endothelial cells. Human PBMCs were cultured in either normal NaCl (NS, 150 mM) or high NaCl (HS, 190 mM) for 48 hours. Flow cytometry indicated a striking increase in AS DCs by exposure to HS compared to NS (516 ± 181 vs 201 ± 57/ml) and this was prevented by co-treatment of cells with the salt-sensing Serum Glucocorticoid Kinase 1 inhibitor GSK650394. As a second approach, we co-cultured human aortic endothelial cells (HAECs) with PBMCs from normotensive donors and exposed the HAEC monolayer to either normal (5%) or hypertensive cyclical stretch (10%) for 24 hours. Co-culture of PBMCs with HAECs exposed to 10% stretch doubled AS DCs as compared to PBMCs cultured with HAECs undergoing 5% stretch (1.4 ± 0.5 vs 0.7 ± 0.3%; P=0.0217). These data show that AS DC population are increased in hypertensive patients and that known hypertensive stimuli in vitro promote formation of AS DCs. Thus, AS DCs seem to be an important immune cell subset in human hypertension and might be a novel therapeutic target for this disease.

Dendritic Cell Amiloride-Sensitive Channels Mediate Sodium-Induced Inflammation and Hypertension

Sodium accumulates in the interstitium and promotes inflammation through poorly defined mechanisms. We describe a pathway by which sodium enters dendritic cells (DCs) through amiloride-sensitive channels including the alpha and gamma subunits of the epithelial sodium channel and the sodium hydrogen exchanger 1. This leads to calcium influx via the sodium calcium exchanger, activation of protein kinase C (PKC), phosphorylation of p47^phox, and association of p47^phox with gp91^phox. The assembled NADPH oxidase produces superoxide with subsequent formation of immunogenic isolevuglandin (IsoLG)-protein adducts. DCs activated by excess sodium produce increased interleukin-1β (IL-1β) and promote T cell production of cytokines IL-17A and interferon gamma (IFN-γ). When adoptively transferred into naive mice, these DCs prime hypertension in response to a sub-pressor dose of angiotensin II. These findings provide a mechanistic link between salt, inflammation, and hypertension involving increased oxidative stress and IsoLG production in DCs.

Abstract 132: Monocytes Activation by Salt is Associated With Cardiovascular Risk Factors

Several studies have established a relationship between hypertension and salt intake; however the mechanisms by which salt causes hypertension are poorly understood. There is also evidence that sodium (Na+) accumulates in the interstitium with aging and hypertension in concentrations exceeding the plasma. We tested the hypothesis that increased NaCl would convert human monocytes to an inflammatory phenotype and to define mechanisms involved. We exposed monocytes from 17 human volunteers to normal physiological NaCl (NS: 150 mM/L), elevated NaCl (HS: 190 mM/L), or an equiosmoloar concentration of mannitol. Exposure of human monocytes to high salt, but not mannitol, increased formation of immunogenic isolevuglandins (isoLG) (NS: 1688±384 vs Mann:1762±429 vs HS: 2381± 635 MFI p<0.002). This was associated with an increase in the dendritic cell (DC) marker CD83 (NS: 503±81 vs Mann: 530± 106 vs HS: 764 ± 136 MFI p<0.001). Exposure to high salt also stimulated production of IL-6 (NS: 2145±771, Mann: 1122±295 and HS: 5187±1146 pg/mL, p=0.04), IL-β (NS: 94±35, Mann: 62±16 and HS: 224±98 pg/mL, p=0.01) and TNF-α (NS:1.9±0.3, Mann: 3.42±1.4 and HS: 4.4±2.1, p<0.0001). In additional experiments, we found that prolonged (7 day) exposure to high salt increased surface expression of CD209, another DC marker (NS: 22±9 vs HS: 34 ± 14, p=0.001) and promoted conversion of the cells to a DC morphology. The propensity for monocytes to respond to NaCl was influence by the patient’s risk factors. The increase in IsoLG (HS-NS) correlated with pulse pressure (mmHg, r=0.51, <0.04), BMI (Kg/m2, r=0.66, p=0.005), total cholesterol (mg/dL, r=0.55, p<0.05) and glucose (mg/dL, r=0.72, p=0.003). Stepwise multivariate regression revealed that BMI and pulse pressure are independent predictors of IsoLG formation in response to salt. These findings suggest that high extracellular NaCl promotes differentiation and activation of monocytes and that these pleotropic inflammatory cells exhibit a previously undefined salt sensitivity corresponding to patients’ underlying risk factor profile.

Abstract 063: Mechanical Stretch on Endothelial Cells Promotes Monocyte Activation and Differentiation into Immunogenic Dendritic Cells via STAT3

Mechanical stretch activates the endothelium to produce reactive oxygen species and expression of adhesion molecules and cytokines. Human monocytes that traverse the endothelium differentiate into dendritic cells (DCs) upon exposure to a pro-inflammatory state. We hypothesized that human endothelial cells exposed to mechanical stretch will promote conversion of human monocytes into activated DCs. We co-cultured human aortic endothelial cells (HAECs) with monocytes from normotensive human donors and exposed the endothelial cells to either normal (5%) or hypertensive (10%) uniaxial cyclical stretch for 48 hours. Co-culturing monocytes with HAECs exposed to 10% stretch showed a marked increase in pro-inflammatory cytokines such as IL-6, IL-23A and IL-1β compared to 5% stretch. HAECs exposed to 10% stretch promoted monocytes in culture to differentiate into DCs. We have shown that DCs from hypertensive mice accumulate isolevuglandins (IsoLGs) that adduct to proteins and promote T cell activation. Thus, we performed intracellular staining and flow cytometry and found that these monocytes significantly accumulate higher levels of IsoLG-adducted proteins compared to 5% stretch (69.7 ± 5.8 vs 10.8 ± 1.85, respectively). In addition, monocytes co-cultured with endothelial cells exposed to 10% stretch expressed phosphorylated STAT3 (pSTAT3), which was blocked by stattic, a STAT3 inhibitor. Similarly, monocytes co-cultured with HAECs exposed to 10% stretch induced a 1,500-fold and a 1,300-fold increase in CD4 + and CD8 + T cell proliferation; while, inhibition of STAT3 prevented this T cell proliferation. To test if this is due to cell-cell contact, we seeded monocytes in a transwell with endothelial cells exposed to either 5% or 10% stretch. We found that these monocytes expressed DC markers, pSTAT3, and accumulated IsoLG-peptides when exposed to hypertensive mechanical stretch. In addition, angiotensin II (490ng/kg/min) infusion of C57Bl/6 mice increased pSTAT3 in monocytes, macrophages, and DCs in the renal and vascular tissue compared to sham controls. Thus, our data indicate that endothelial cells exposed to mechanical stretch cross-talk with monocytes to promote differentiation into DCs known to be immunogenic via STAT3.

Oxidative Stress and Hypertensive Diseases

It has become clear that reactive oxygen species (ROS) contribute to the development of hypertension via myriad effects. ROS are essential for normal cell function; however, they mediate pathologic changes in the brain, the kidney, and blood vessels that contribute to the genesis of chronic hypertension. There is also emerging evidence that ROS contribute to immune activation in hypertension. This article discusses these events and how they coordinate to contribute to hypertension and its consequent end-organ damage.

Abstract 054: Mechanical Stretch on Endothelial Cells Promotes Monocyte Differentiation Into Immunogenic Dendritic Cells

We have shown that dendritic cells (DCs) from hypertensive mice and monocytes in humans accumulate highly reactive isolevuloglandins (isoLGs) or isoketals that adduct to protein lysines and promote T cell activation, specifically. Monocytes that traverse the endothelium have three different fates: reemerge into circulation as an activated monocyte; differentiate into macrophages or into monocyte-derived DCs. We hypothesized that human endothelial cells exposed to hypertensive mechanical stretch will promote conversion of human monocytes into immunogenic DCs. We co-cultured human aortic endothelial cells (HAECs) with monocytes from normotensive human donors and exposed the HAEC monolayer to either normal cyclical stretch (5%) or hypertensive uniaxial cyclical stretch (10%) for 48 hours. We found that co-culture of monocytes with HAECs exposed to 10% mechanical stretch markedly increased monocyte mRNA expression of the Th17 polarizing cytokines IL-6, I-23A and IL-1β and the p22 phox subunit of the NADPH oxidase compared to 5% stretch. HAECs exposed to 10% stretch promoted monocytes in culture to differentiate into DCs, as evidenced by the surface expression of DC-SIGN, CD83 and the co-stimulatory marker CD86. These monocytes also accumulated isoLG-modified proteins compared to controls (69.73 ± 5.802 vs 10.79 ± 1.854 respectively, p = 0.0001) as evidenced by intracellular staining and flow cytometry. We also co-cultured these monocytes with T cells from the same patient and examined proliferation of the latter using CFSE. Monocytes co-cultured with 10% stretched HAECs induced a 1,500-fold increase in CD4 + T cell proliferation and a 1,300-fold increase in CD8 + T cells proliferation. In addition, monocytes co-cultured with 10% stretched HAECs had a 2-fold increase in phosphorylated STAT3 expression compared to 5% stretch cultures. Conversely, monocytes-HAEC cultures exposed to 10% stretch and treated with STAT3 inhibitor, stattic, reduced their differentiation into DCs and prevented both CD4 + and CD8 + T cell proliferation. These data show that endothelial cells exposed to mechanical stretch cross-talk with monocytes to promote differentiation into activated DCs potentially via the STAT3 pathway.

Abstract 354: Mechanical Stretch on Endothelial Cells Promotes Monocyte Differentiation into Immunogenic Dendritic Cells

Fatty acid oxidation leads to formation of highly reactive isoketals that adduct to protein lysines. We have shown that dendritic cells (DCs) from hypertensive mice accumulate isoketal-adducted proteins and promote T cell activation. In hypertension, the endothelium is activated to produce reactive oxygen species and to express adhesion molecules and chemokines that attract inflammatory cells. Human monocytes that traverse the endothelium differentiate into monocyte-derived DCs upon exposure to a pro-inflammatory state. We hypothesized that human endothelial cells exposed to mechanical stretch promote conversion of human monocytes into immunogenic DCs. We co-cultured human aortic endothelial cells (HAECs) with monocytes from normotensive human donors and exposed the HAEC monolayer to either normal cyclical stretch (5%) or hypertensive cyclical stretch (10%) using the Flexcell ® Tension System for 48 hours. We found that co-culture of monocytes with HAECs exposed to 10% mechanical stretch markedly increased monocyte mRNA expression of the Th17 polarizing cytokines IL-6, I-23A and IL-1β and monocyte chemokine CCL4 and the p22 phox subunit of the NADPH oxidase compared to 5% stretch. HAECs exposed to 10% stretch promoted monocyte in culture to differentiate into DCs, as evidenced by the surface expression of DC-SIGN, CD83 and the co-stimulatory marker CD86. These monocytes also had an accumulation of isoketal-adducted proteins compared to controls (69.73 ± 5.802 vs 10.79 ± 1.854 respectively, p = 0.0001) as evidenced by intracellular staining and flow cytometry. Monocytes co-cultured with 10%-stretched HAECs induced a 1,500-fold increase in CD4 + T cell proliferation and a 1,300-fold increase in CD8 + T cells proliferation as monitored by CFSE compared to 5% stretch controls. Conversely, monocytes-HAEC cultures exposed to 10% stretch and treated with STAT3 inhibitor, stattic, prevented both CD4 + and CD8 + T cell proliferation. These data show that endothelial cells exposed to mechanical stretch cross-talk with monocytes to promote their differentiation into immunogenic DCs potentially via the JAK/STAT3 pathway. These findings give insight into a new mechanism of lymphocyte activation in the vascular endothelium during hypertension.

Abstract P616: Renal Sympathetic Outflow And Beta-adrenergic Signaling Promote Dendritic Cell Activation In Hypertension

Hypertension is associated with increased sympathetic outflow and activation of adaptive immunity. In hypertensive states, proteins that are oxidatively modified by highly reactive γ-ketoaldehydes (isoketals) accumulate in dendritic cells (DCs). These isoketal-protein adducts are immunogenic and lead to subsequent activation of T cells. We hypothesized that renal sympathetic nerves link the central nervous system to immune activation in hypertension. To test this, we performed bilateral renal denervation (RDN) in C57BL/6 mice by applying phenol to the renal artery. One week later, mice received an subcutaneous infusion of angiotensin II (490 ng/kg/min) for 14 days. RDN lowered the hypertensive response to angiotensin II infusion (130±3 vs. 161±3 mmHg) as measured by telemetry. By flow cytometry, we found that RDN reduced accumulation of T cells in the kidney. Ang II infusion caused resulted in 15-25% increases in expression of the maturation markers CD80 and CD86, as well as 2-fold increase in isoketal adducts in the DCs of spleen. It also increased IL-1α, IL-1β, and IL-6 production by splenic DCs by 4 to 6-fold. These increases were attenuated by RDN. Having confirmed that DCs express almost every subtype of adrenergic receptor by real time PCR, we further determined if sympathetic neurotransmitters contribute to DC activation by treating bone marrow-derived DCs with either norepinephrine (NE) or neuropeptide Y (NPY) in vitro. As measured by flow cytometry, NE dose-dependently increased isoketal-protein adducts in DCs (vehicle: 19 ± 3 vs. 3 μmol/L: 39 ± 4%). This was prevented by pretreating cells with the β-adrenergic antagonist propranolol (1 μmol/L), but not by blocking α 1 or α 2 adrenoreceptors with prazosin and yohimbine. In contrast, NPY did not affect DC isoketal-protein content. Therefore, our data indicate that renal sympathetic nerves increase isoketal-adduct formation in DCs via β-adrenergic signaling and that this contributes to the activation of adaptive immunity in hypertension. These data suggest that beta blockade might have previously unappreciated anti-inflammatory effects in the treatment of hypertension.

Renal Denervation Prevents Immune Cell Activation and Renal Inflammation in Angiotensin II-Induced Hypertension

RATIONALE

Inflammation and adaptive immunity play a crucial role in the development of hypertension. Angiotensin II and probably other hypertensive stimuli activate the central nervous system and promote T-cell activation and end-organ damage in peripheral tissues.

OBJECTIVE

To determine if renal sympathetic nerves mediate renal inflammation and T-cell activation in hypertension.

METHODS AND RESULTS

Bilateral renal denervation using phenol application to the renal arteries reduced renal norepinephrine levels and blunted angiotensin II-induced hypertension. Bilateral renal denervation also reduced inflammation, as reflected by decreased accumulation of total leukocytes, T cells, and both CD4+ and CD8+ T cells in the kidney. This was associated with a marked reduction in renal fibrosis, albuminuria, and nephrinuria. Unilateral renal denervation, which partly attenuated blood pressure, only reduced inflammation in the denervated kidney, suggesting that this effect is pressure independent. Angiotensin II also increased immunogenic isoketal-protein adducts in renal dendritic cells (DCs) and increased surface expression of costimulation markers and production of interleukin (IL)-1α, IL-1β, and IL-6 from splenic DCs. Norepinephrine also dose dependently stimulated isoketal formation in cultured DCs. Adoptive transfer of splenic DCs from angiotensin II-treated mice primed T-cell activation and hypertension in recipient mice. Renal denervation prevented these effects of hypertension on DCs. In contrast to these beneficial effects of ablating all renal nerves, renal afferent disruption with capsaicin had no effect on blood pressure or renal inflammation.

CONCLUSIONS

Renal sympathetic nerves contribute to DC activation, subsequent T-cell infiltration and end-organ damage in the kidney in the development of hypertension.

DC isoketal-modified proteins activate T cells and promote hypertension

Oxidative damage and inflammation are both implicated in the genesis of hypertension; however, the mechanisms by which these stimuli promote hypertension are not fully understood. Here, we have described a pathway in which hypertensive stimuli promote dendritic cell (DC) activation of T cells, ultimately leading to hypertension. Using multiple murine models of hypertension, we determined that proteins oxidatively modified by highly reactive γ-ketoaldehydes (isoketals) are formed in hypertension and accumulate in DCs. Isoketal accumulation was associated with DC production of IL-6, IL-1β, and IL-23 and an increase in costimulatory proteins CD80 and CD86. These activated DCs promoted T cell, particularly CD8+ T cell, proliferation; production of IFN-γ and IL-17A; and hypertension. Moreover, isoketal scavengers prevented these hypertension-associated events. Plasma F2-isoprostanes, which are formed in concert with isoketals, were found to be elevated in humans with treated hypertension and were markedly elevated in patients with resistant hypertension. Isoketal-modified proteins were also markedly elevated in circulating monocytes and DCs from humans with hypertension. Our data reveal that hypertension activates DCs, in large part by promoting the formation of isoketals, and suggest that reducing isoketals has potential as a treatment strategy for this disease.

Abstract 069: Isoketals in Monocyte-Derived Dendritic Cells Activate T Cells and Promote Hypertension

Fatty acid oxidation leads to formation of highly reactive γ-ketoaldehydes termed isoketals that adduct to protein lysines. We have shown that hypertension causes isoketals to accumulate in dendritic cells (DCs) and activate T cells. Human monocytes traversing the endothelium differentiate into DCs expressing CD83, MHC-II, and CD11c. We hypothesized that oxidative stress catalyzes the formation of isoketals which alters monocyte and DC function to promote monocyte transformation to DCs and T cell activation. Thus, we co-cultured human monocytes with aortic endothelial cells exposed to either a hypertensive 10% stretch or a normotensive 5% stretch for 48 hours using the Uniflex® culture system. We used flow cytometry to detect human DC markers (CD14-/CD83+) in monocytes exposed to stretch. We detected conversion of CD14-/CD83+ from CD14+ human monocytes and found they contained increased levels of isoketal-ligated proteins in the 10% compared to 5% stretch (77.47 ± 7.3 vs. 12.14 ± 3.5). We also found a 1.8 fold increase of the CD86 activation marker compared to controls. Exposure of murine monocyte-derived DCs to tert-butyl hydroperoxide (t-BHP) led to a 3-fold increase in isoketals and a 2-fold increase in CD86 in the CD11b+/CD11c+ population compared to controls. Isoketal formation in DCs exposed to t-BHP was scavenged with pre-treatment of 2-hydroxybenzylamine (2-HOBA) in vitro. DCs treated with t-BHP were co-cultured with T cells for 7 days. This promoted T cell survival and proliferation of CD8+ and CD4+ T cells compared to untreated controls; this effect was attenuated with pre-treatment of 2-HOBA. Moreover, adoptive transfer of t-BHP treated DCs to normal mice elevated the hypertensive response to a generally subpressor dose of angiotensin-II (128 ± 0.80 vs. 114 ± 0.48 in controls). We conclude that oxidant stress and isoketal formation in murine DCs promote T cell activation and hypertension. We hypothesize that exposure to hypertensive stretch in human endothelial cells transfers an oxidant signal to monocytes and promotes their transformation to DCs, which mature and promote an immune response. These findings provide a mechanism as to how T cells are activated in hypertension and provide insight into the inflammatory nature of this disease.

Abstract 624: Induction of Oxidative Stress in Dendritic Cells Promotes Isoketal Formation and Activation of T Cells

We and others have previously shown that T cells play an important role in hypertension, but the mechanisms by which they are activated remains undefined. Dendritic cells present antigens and secrete cytokines that modify T cell polarization. The NADPH oxidase also contributes to hypertension via multiple mechanisms. We have found that dendritic cells (DCs) from ang II-infused mice have a 5-fold increase in superoxide production by NADPH oxidase. Superoxide catalyzes the formation of H2-isoprostanes, which rearrange to form reactive γ-ketoaldehydes termed isoketals that adduct to protein lysines which renders them immunogenic. We hypothesized that oxidative stress catalyzes the formation of isoketals which alters the function of dendritic cells leading to inflammation and hypertension. Thus, we exposed DCs from spleens of C57Bl/6 mice to tert-Butyl hydroperoxide (t-BHP) for 30 minutes. Using flow cytometry, we found that t-BHP exposure increased levels of isoketal-ligated proteins in the CD11b+/CD11c+ DCs population compared to control (19.6 ± 3.7 vs. 10.6 ± 2.5, respectively; P=0.035). Importantly, we found DCs exposed to t-BHP become capable of activating T cells. After exposure to this oxidant for 30 minutes, DCs were cultured with autologous T cells for 7 days and proliferation was monitored by carboxyfluorescein succinimidyl ester (CFSE) and flow cytometry. Exposure of DCs to t-BHP promoted a 4-fold increase in proliferation of autologous CD8+ T cells compared to controls. This was also associated with a modest proliferation of CD4+ T cells. Thus, hypertension promotes oxidative stress in DCs. Induction of oxidative stress in DCs leads to formation of highly reactive isoketals, which alters the function of endogenous proteins. Formation of isoketals in DCs leads to T cell and, in particular, CD8 activation. These findings provide a mechanism as to how T cells are activated in hypertension and provide insight into the inflammatory nature of this disease.

The c-Myb target gene neuromedin U functions as a novel cofactor during the early stages of erythropoiesis

The requirement of c-Myb during erythropoiesis spurred an interest in identifying c-Myb target genes that are important for erythroid development. Here, we determined that the neuropeptide neuromedin U (NmU) is a c-Myb target gene. Silencing NmU, c-myb, or NmU's cognate receptor NMUR1 expression in human CD34(+) cells impaired burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) formation compared with control. Exogenous addition of NmU peptide to NmU or c-myb siRNA-treated CD34(+) cells rescued BFU-E and yielded a greater number of CFU-E than observed with control. No rescue of BFU-E and CFU-E growth was observed when NmU peptide was exogenously added to NMUR1 siRNA-treated cells compared with NMUR1 siRNA-treated cells cultured without NmU peptide. In K562 and CD34(+) cells, NmU activated protein kinase C-βII, a factor associated with hematopoietic differentiation-proliferation. CD34(+) cells cultured under erythroid-inducing conditions, with NmU peptide and erythropoietin added at day 6, revealed an increase in endogenous NmU and c-myb gene expression at day 8 and a 16% expansion of early erythroblasts at day 10 compared to cultures without NmU peptide. Combined, these data strongly support that the c-Myb target gene NmU functions as a novel cofactor for erythropoiesis and expands early erythroblasts.