Hypertension 2016 Scientific Sessions Abstracts
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Hypertension 2016 Scientific Sessions Abstracts 001 self-antigens. This transgenic mouse line expresses membrane-bound OVA in pancreatic Hypertension Induces Heightened Activity of islet β cells and kidney proximal tubular cells. the Adaptive Immune System When OT-I cells (5x106) are injected into RIP- mOVA mice, they activate by cross-presentation Tuantuan Zhao, Dept of Biomedical Sciences. of OVA and cause insulitis and diabetes. RIP- Cedars-Sinai Medical Ctr, Los Angeles, CA; Xiao mOVA mice were made hypertensive with Z Shen, Dept of Physiology, Zhejiang Univ Sch of either AngII or L-NAME. When OT-I cells were Med, Hangzhou, Zhejiang, China; Ellen A infused into hypertensive RIP-mOVA mice, they Bernstein, Kenneth E Bernstein, Dept of rapidly developed much higher blood glucose Biomedical Sciences. Cedars-Sinai Medical Ctr, levels as compared to equivalently treated Los Angeles, CA normotensive RIP-mOVA mice. For example, Adaptive immunity plays a key role in the comparing mice 3 weeks after AngII and 1 wk pathogenesis of hypertension, but how does after OT-I cells to normotensive mice 1 wk after hypertension affect immunity? To study this, OT-I cells, blood glucose was 331 ± 47 mg/dl in splenic dendritic cells (DC) and peritoneal the hypertensive mice vs. 168 ± 39 mg/dl in the macrophages were isolated from normotensive normotensive controls. Also, far more and hypertensive angiotensin II (AngII)-infused pancreatic islets were infiltrated by T cells in the C57BL6/J mice (490 ng/kg/min, 2 wk). These hypertensive mice (AngII 78%, 31 of 40; L-NAME antigen presenting cells (APCs) were loaded 72%, 21 of 29; control 13%, 10 of 75). In with ovalbumin (OVA) or the OVA MHC class I conclusion, hypertension itself is associated epitope SIINFEKL (SKL) for 3h. Then, splenocytes with higher activity of APC presentation of from OT-I mice, containing OVA-specific, CD8+ T foreign and self-antigens which may explain cells (OT-I cells), were added for 4h. Flow why hypertension induces inflammation. cytometry showed significantly more activated T. Zhao: None. X.Z. Shen: None. E.A. Bernstein: T cells expressing CD69 when stimulated with None. K.E. Bernstein: None. APCs from AngII-treated mice than equivalent cells from naïve mice (As example, DC+OVA: 2.9 Funding: No ± 0.4% vs. 1.8 ± 0.3% ,P<0.05; DC+SKL: 13.9 ± 0.9 % vs. 7.4 ± 1.1%, P<0.01;). To study antigen Funding Component: presentation in vivo, we immunized AngII and 002 sham treated mice with OVA and adjuvant. Consistently more OVA-specific CD8+ T cells Adoptive Transfer of CD8 T Cells With were induced in the blood (2.7 ± 0.2% vs. 1.2 ± Constitutively Active Pi3kγ Induces 0.4%, P<0.05) and the spleen (2.6 ± 0.3% vs. 1.5 Hypertension in Mice ± 0.2%, P<0.05) of hypertensive mice vs. sham when measured by flow using a H-2kb-SKL Daniela Carnevale, Sapienza Univ of Rome at tetramer. IRCCS Neuromed, Pozzilli (IS), Italy; Maria RIP-mOVA mice were also used to study if Piacenti, Giuseppe Cifelli, Roberta Iacobucci, hypertension affects APC cross-presentation of IRCCS Neuromed, Pozzilli (IS), Italy; Giuseppe Lembo, Sapienza Univ of Rome at IRCCS overactivation of PI3Kγ signaling in this immune Neuromed, Pozzilli (IS), Italy cell type, we performed an adoptive transfer of CD8 T cells isolated from CAAX mice in WT mice. Strikingly we found that CD8 T cells with In the field of research exploring the connection constitutively active PI3Kγ were effective to existing between hypertension and immune induce hypertension in naïve mice. These data system, CD8 effector T cells emerge as the suggest that in the development of possible mediators of target organ colonization. hypertension, PI3Kγ signaling in CD8 T cells is In the absence of overt inflammation or crucial for their accumulation in the kidney, pathogen response, naïve T cells circulate from likely contributing to increase in blood pressure the blood into secondary lymphoid organs, by altering renal function. where, upon challenge, become activated. Then, they differentiate into effector T cells, D. Carnevale: None. M. Piacenti: None. G. which display typical activation patterns. Cifelli: None. R. Iacobucci: None. G. Lembo: However, less is known about the intracellular None. signaling pathways that are responsible for the acquisition of effectors functions in T cells. The Funding: No p110γ isoform of the PI3K family has unique Funding Component: features, being crucially involved in the immune and cardiovascular systems. On this issue, we 003 have described that PI3Kγ has a crucial role in Direct and Indirect Effects of Prostaglandin E2 blood pressure regulation, being KO mice and Its EP1/EP3 Receptors on Dendritic Cell protected from AngII-induced hypertension. Activation in Mice with L-NAME/High Salt- Moreover, we found that mice with a induced Hypertension constitutively active PI3Kγ isoform (CAAX mice) were spontaneously hypertensive (SBP: CAAX Liang Xiao, Hana A Itani, Maria P Kraemer, 135 ± 3 vs WT 105 ± 4 mmHg, p<0.001). Richard M Breyer, David G Harrison, Vanderbilt Interestingly, PI3Kγ is known to play a selective Univ, Nashville, TN role in regulating the migration of effector CD8 T cells, even though there was no effect of PI3Kγ in naïve T cells. Thus we explored the We recently identified a pathway underlying possible involvement of PI3Kγ in the crosstalk immune activation in hypertension. Proteins between hypertension and immunity. CAAX oxidatively modified by reactive γ- mice displayed a significant infiltration of ketoaldehydes (isoketals) accumulate in activated CD8+CD69+ T cells in kidney, as dendritic cells (DCs). These are immunogenic compared to WT mice (10.2 ± 2.1 vs 2.8 ± 0.6 and lead to subsequent T lymphocytes *104 cells/kidney, p<0.01). At the functional activation. The local signals that stimulate DCs level, this phenotype was associated with to accumulate isoketal adducts remain enlarged Bowman’s spaces and fibrosis in the undefined. Prostaglandin E2 (PGE2) has been kidney of CAAX mice, leading to disruption of implicated in the inflammation associated with renal function, as shown by later development hypertension. We hypothesized that PGE2 via its of proteinuria. In the end, to demonstrate EP3 receptor contributes to DC activation in whether the CAAX hypertensive phenotype, hypertension. EP3-/- mice and wild type (WT) associated to renal damage after CD8 littermates were exposed to sequential colonization, could be ascribed to the hypertensive stimuli involving an initial 2-week exposure to the NOS inhibitor L-NAME (LN) in Aberrant CD4+ T Cell Function in Stroke-prone drinking water, a 2 week washout period, and a Hypertensive Rats Due to a Mutation in Stim1 subsequent 4% high salt diet (HS) for 3 weeks. In WT mice, this protocol increased systolic Isha S Dhande, Mykola Mamenko, Yaming Zhu, pressure from 123±2 to 148±8 mmHg (p<0.05), Oleh Pochynyuk, Univ of Texas Health Science and renal CD4+ and CD8+ effector memory T Ctr, Houston, TX; Scott Wenderfer, Michael cells by 2 to 3 fold. This was associated with a Braun, Baylor Coll of Med, Houston, TX; Peter striking accumulation of isoketal protein Doris, Univ of Texas Health Science Ctr, adducts in splenic DCs. However, the increases Houston, TX in blood pressure, renal T cell infiltration and DC isoketal formation were completely prevented The genetic mechanism of end organ injury in -/- in EP3 mice. We further hypothesized that EP3 hypertension may involve gene variation in receptors contribute to oxidative stress genes participating in inflammation and its production in the kidney. As measured by regulation. We identified a novel truncating dihydroethidium with confocal microscopy, the mutation in the hypertensive end organ injury- LNHS protocol induced marked increases in prone spontaneously hypertensive rat (SHR- superoxide production in WT mice, but not in A3/SHRSP) line affecting the C-terminus of -/- EP3 mice. To examine the direct effects of STIM1, a protein involved in the store-operated PGE2, splenic DCs were incubated with PGE2 in Ca2+ entry (SOCE) pathway. The genomes of vitro for 24 hours. PGE2 dose-dependently injury-resistant SHR lines, including SHR-B2 increased isoketal-adduct formation in DCs used here, encode the ‘wild-type’ STIM1. SOCE (vehicle: 8.8±5.1% vs. 50 nM PGE2: 41.4±11.7%, is required by T cells to activate the p<0.05). Interestingly, this effect was not transcription factor NFAT and regulate T cell blocked by the EP3 receptor antagonist DG-041 proliferation and cytokine production. T cell (30 nM), but was completely prevented by the receptor (TCR) stimulation depletes intracellular EP1 receptor blocker SC-51322 (20 μM). These Ca2+ stores, activates the ER Ca2+-sensor STIM1 data indicate both direct and indirect roles of and results in SOCE. We tested the effect of PGE2 in DC activation in hypertension. In vivo, STIM1 mutation on lymphocyte SOCE and found PGE2 has a predominant effect on EP3 receptors it was dramatically reduced in SHR-A3, but not to enhance renal vascular ROS production, 2+ in SHR-B2 (maximal [Ca ]i: 150.5±34.9 vs which likely leads to isoketal-adduct formation 521.5±42.6 nM, p<0.0001). Flow cytometric and accumulation in DCs. PGE2 also acts directly analysis of circulating T cell subsets revealed on DCs via its EP1 receptors to stimulate comparable levels of CD4+ and CD8+ T cells in intracellular isoketal formation. Together, these both lines, however circulating findings provide additional information as to + + + CD4 CD25 FoxP3 Tregs were reduced in SHR-A3 how PGE2 modulates inflammation in compared to SHR-B2 (4.34±0.59 vs 7.12±0.33%, hypertension. p=0.01). TCR-induced lymphocyte proliferation L. Xiao: None. H.A. Itani: None. M.P. Kraemer: was similar in both SHR-A3 and SHR-B2.