Immunosuppressive drugs reduce the incidence of organ rejection following transplantation and the severity of autoimmune diseases;however these drugs can cause endothelial dysfunction and hypertension which is a major limitation to their use. The objective of the current proposal is to elucidate the immunological mechanisms by which alterations in T cells caused by the immunosuppressive drugs cyclosporine A (CsA) and FK506 (tacrolimus) alter endothelial function and blood pressure regulation. We will test the overall hypothesis that CsA- and FK506-induced decreases in beneficial regulatory T cells (Tregs) and increases in detrimental Th17 cells contribute to the development of endothelial dysfunction and hypertension. To test this hypothesis we will pursue 3 aims.
Specific Aim 1 will examine the effects of Treg-derived and Th17 cell-derived cytokines on endothelial function and blood pressure regulation. If decreased Tregs and increased Th17 cells caused by CsA and FK506 contribute to the endothelial dysfunction and hypertension, then cytokines derived from these T cell subsets should directly modulate endothelial function and blood pressure. Specifically, IL-17 should directly induce endothelial dysfunction and hypertension and this should be prevented by Tregs or Treg- derived cytokines.
Specific Aim 2 will determine the direct effects of lymphocytes from CsA-treated and FK506-treated mice on endothelial function. Lymphocytes from mice treated with CsA or FK506 should directly cause endothelial dysfunction in endothelial cells and blood vessels isolated from control mice. Additionally, isolated control endothelial cells and blood vessels should exhibit normal endothelial function following incubation with lymphocytes from CsA-treated or FK506-treated mice following inhibition of Th17 cells or augmentation of Tregs.
Specific Aim 3 will determine the role of lymphocytes in CsA-induced and FK506- induced hypertension. Deficiency of Th17 cells and/or augmentation of Tregs should normalize blood pressure in CsA-treated and FK506-treated mice. Additionally, adoptive transfer of T cells from CsA-treated or FK506- treated mice into control mice should cause endothelial dysfunction and hypertension. To this end, we will use various combinations of pharmacologic and/or genetic perturbations of Tregs and Th17 cells in endothelial cells, isolated blood vessels, and mice. Completion of the aims will identify the molecular mechanisms responsible for, as well as possible therapies to prevent, the endothelial dysfunction and hypertension caused by CsA and FK506.

Public Health Relevance

Immunosuppressive drugs reduce the incidence of organ rejection following transplantation and the severity of autoimmune diseases;however these drugs can cause high blood pressure and cardiovascular disease. Our goal is to determine how these drugs change components of the immune system and how this affects blood vessel function and the development of high blood pressure. Our research will use various genetically altered mice and techniques to understand the mechanisms of how this happens and test various therapies in an effort to prevent high blood pressure caused by these immunosuppressive drugs.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
High Priority, Short Term Project Award (R56)
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Hypertension and Microcirculation Study Section (HM)
Program Officer
Gao, Yunling
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Texas A&M University
Internal Medicine/Medicine
Schools of Medicine
College Station
United States
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Chiasson, Valorie L; Pakanati, Abhinandan R; Hernandez, Marcos et al. (2017) Regulatory T-Cell Augmentation or Interleukin-17 Inhibition Prevents Calcineurin Inhibitor-Induced Hypertension in Mice. Hypertension 70:183-191
Nguyen, Hoanglan; Chiasson, Valorie L; Chatterjee, Piyali et al. (2013) Interleukin-17 causes Rho-kinase-mediated endothelial dysfunction and hypertension. Cardiovasc Res 97:696-704
Chiasson, Valorie L; Jones, Kathleen A; Kopriva, Shelley E et al. (2012) Endothelial cell transforming growth factor-? receptor activation causes tacrolimus-induced renal arteriolar hyalinosis. Kidney Int 82:857-66
Chiasson, Valorie L; Talreja, Deepa; Young, Kristina J et al. (2011) FK506 binding protein 12 deficiency in endothelial and hematopoietic cells decreases regulatory T cells and causes hypertension. Hypertension 57:1167-75
Chiasson, Valorie L; Munshi, Nidhi; Chatterjee, Piyali et al. (2011) Pin1 deficiency causes endothelial dysfunction and hypertension. Hypertension 58:431-8
Tinsley, John H; Chiasson, Valorie L; Mahajan, Ashutosh et al. (2009) Toll-like receptor 3 activation during pregnancy elicits preeclampsia-like symptoms in rats. Am J Hypertens 22:1314-9
Tinsley, John H; Chiasson, Valorie L; South, Sanique et al. (2009) Immunosuppression improves blood pressure and endothelial function in a rat model of pregnancy-induced hypertension. Am J Hypertens 22:1107-14
Cook, Leslie G; Chiasson, Valorie L; Long, Cheng et al. (2009) Tacrolimus reduces nitric oxide synthase function by binding to FKBP rather than by its calcineurin effect. Kidney Int 75:719-26