The mechanisms regulating blood pressure are known to have strong genetic components; however, the specific genes involved in the pathogenesis of hypertension are not well defined. Key regulators are atrial and brain natriuretic peptides (ANP, BNP) signaling through their cognate natriuretic peptide receptor-A (NPRA) and the second messenger cGMP. The ANP-BNP/NPRA system plays critical roles in the regulation of blood pressure and reno-vascular homeostasis. There is a strong association of polymorphisms in the genes that encode ANP (Nppa), BNP (Nppb), and NPRA (Npr1) with high blood pressure and cardiovascular dysfunction in humans. These phenotypes can be recapitulated using global Npr1 gene-knockout system in mice. Both male and female mice lacking global Npr1 gene (Npr1-/-) exhibit high blood pressure, but specifically male Npr1 mice suffer from hypertension, heart failure, and sudden death at adult age. It is not clear how the lack of Npr1 in the specific cell-types of kidneys and vasculature progressively leads to hypertension, nor what underlies the observed sex-differences in the global Npr1-/- mice. The Npr1 deletion exhibiting malignant hypertension in mice is significant and complements clinical findings of polymorphisms in Nppa, Nppb, and Npr1 in humans. The mechanistic understanding of how the absence of Npr1 divergently affects blood pressure in a sex-related manner remains an important yet unanswered question. We hypothesize that cell- specific deletion of Npr1 plays critical roles in the development of molecular and cellular perturbations of immunogenic and inflammatory mechanisms leading to activation of Toll-like receptors (TLRs), redox-sensitive transcription factor nuclear factor kappa B (NF-?B), adaptive T cells, and macrophages. The long-term goal of this proposal is to determine the molecular and genetic factors that contribute to immunogenic chronic inflammation leading to hypertension and reno-vascular dysfunction. The overall objective of the proposed studies is to determine the mechanistic aspects of the loss of nephron tubules (NT)- and vascular smooth muscle cell (SMC)-specific Npr1, leading to hypertension and reno-vascular remodeling and dysfunction. The central hypothesis is that the cell-specific loss of Npr1 in the kidneys and vasculature triggers the immunogenic and inflammatory processes that provoke hypertension and end-organ damage in a sex- dependent manner. The proposed specific aims will test the hypotheses: 1) the damage-associated immune receptors contribute to hypertension and reno-vascular dysfunction; 2) the down-stream redox-sensitive cascades trigger high blood pressure and renal-vascular injury and dysfunction; and 3) immunogenic mechanisms provoke hypertension, and renal-vascular disorders. The successful completion of the proposed studies could lead to the identification of much-needed new biomarkers and therapies for the treatment and prevention of hypertension and renal-vascular dysfunction in both genders in humans.

Public Health Relevance

The proposed studies will utilize genetically modified mouse models to provide new insights to delineate the mechanisms of hypertension and renal and vascular injury and dysfunction in a sex-related manner. Renal and vascular functions can become severely impaired with high blood pressure leading to stroke, reno- vascular disorders, and heart failure. Both men and women can have distinct differences in progression of hypertensive disease state. The present proposal targets unique mechanisms that contribute to the molecular basis of hypertension and renal and vascular dysfunction. The findings will help in developing molecular therapeutic strategies to appropriately target treatment and prevention of hypertension and reno-vascular dysfunction in men and women.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL062147-19
Application #
9930111
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
OH, Youngsuk
Project Start
1998-06-01
Project End
2021-03-31
Budget Start
2020-04-01
Budget End
2021-03-31
Support Year
19
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Tulane University
Department
Physiology
Type
Schools of Medicine
DUNS #
053785812
City
New Orleans
State
LA
Country
United States
Zip Code
70118
Somanna, Naveen K; Mani, Indra; Tripathi, Satyabha et al. (2018) Clathrin-dependent internalization, signaling, and metabolic processing of guanylyl cyclase/natriuretic peptide receptor-A. Mol Cell Biochem 441:135-150
Kumar, Prerna; Gogulamudi, Venkateswara R; Periasamy, Ramu et al. (2017) Inhibition of HDAC enhances STAT acetylation, blocks NF-?B, and suppresses the renal inflammation and fibrosis in Npr1 haplotype male mice. Am J Physiol Renal Physiol 313:F781-F795
Sen, Anagha; Kumar, Prerna; Garg, Renu et al. (2016) Transforming growth factor ?1 antagonizes the transcription, expression and vascular signaling of guanylyl cyclase/natriuretic peptide receptor A - role of ?EF1. FEBS J 283:1767-81
Subramanian, Umadevi; Kumar, Prerna; Mani, Indra et al. (2016) Retinoic acid and sodium butyrate suppress the cardiac expression of hypertrophic markers and proinflammatory mediators in Npr1 gene-disrupted haplotype mice. Physiol Genomics 48:477-90
Mani, Indra; Garg, Renu; Pandey, Kailash N (2016) Role of FQQI motif in the internalization, trafficking, and signaling of guanylyl-cyclase/natriuretic peptide receptor-A in cultured murine mesangial cells. Am J Physiol Renal Physiol 310:F68-84
Mani, Indra; Garg, Renu; Tripathi, Satyabha et al. (2015) Subcellular trafficking of guanylyl cyclase/natriuretic peptide receptor-A with concurrent generation of intracellular cGMP. Biosci Rep 35:
Kumar, Prerna; Periyasamy, Ramu; Das, Subhankar et al. (2014) All-trans retinoic acid and sodium butyrate enhance natriuretic peptide receptor a gene transcription: role of histone modification. Mol Pharmacol 85:946-57
Vellaichamy, Elangovan; Das, Subhankar; Subramanian, Umadevi et al. (2014) Genetically altered mutant mouse models of guanylyl cyclase/natriuretic peptide receptor-A exhibit the cardiac expression of proinflammatory mediators in a gene-dose-dependent manner. Endocrinology 155:1045-56
Zhao, Di; Das, Subhankar; Pandey, Kailash N (2013) Interactive roles of NPR1 gene-dosage and salt diets on cardiac angiotensin II, aldosterone and pro-inflammatory cytokines levels in mutant mice. J Hypertens 31:134-44
Tripathi, Satyabha; Pandey, Kailash N (2012) Guanylyl cyclase/natriuretic peptide receptor-A signaling antagonizes the vascular endothelial growth factor-stimulated MAPKs and downstream effectors AP-1 and CREB in mouse mesangial cells. Mol Cell Biochem 368:47-59

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