Vascular smooth muscle (VSM) and endothelium play primary roles in pregnancy-associated vascular adaptations. Peptides of the calcitonin gene-related peptide (CGRP)-family-CGRP, adrenomedullin (AM), and intermedin (IMD)-have been shown to play significant roles in these adaptations. CGRP, AM, and IMD share common receptor components, calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein (RAMP)1, 2, and 3, in different combinations in exerting their biological functions. During the previous funding periods, we have demonstrated that CGRP, AM, and IMD play critical roles in regulating pregnancy-associated vascular adaptations, utero placental functions, and fetal growth. Interestingly, the effect of these peptides varied depending on the vascular bed and between VSM and endothelial cells. Our new preliminary findings suggest variable associations and competitive interactions of RAMPs with CRLR could contribute to the observed differences in peptide-induced relaxation between mesenteric artery (MA) and uterine artery (UA). Tumor necrosis factor- ? (TNF) caused differential and selective decreases in RAMPs or CRLR in VSM and endothelial cells. We hypothesize that differences in vasorelaxations to CGRP, AM, and IMD in both MA and UA are determined by differential association and competitive interaction of different RAMPs with CRLR and that these associations and interactions are cell-specifically downregulated by TNF?. We will utilize intracellular cAMP measurements, shRNA-mediated receptor knockdowns, novel proximity ligation assay (in situ method to quantitatively detect CRLR and RAMP protein proximity associations at the cell membrane level), and functional vascular reactivity studies to test our hypotheses.
Four specific aims are proposed.
Specific Aim 1 : To investigate molecular mechanisms of action for 3 peptides of the CGRP family on MA VSM cells. We will determine competitive association of specific RAMPs with CRLR and cAMP generation in MA VSM cells and vasorelaxation responses to peptides in MA rings with knockdown of specific RAMPs.
Specific Aim 2 : To assess molecular mechanisms of action for 3 peptides of the CGRP family on UA VSM cells. We will determine association of RAMPs with CRLR and cAMP generation in UA VSM and relaxation response to peptides in UA rings with knockdown of specific RAMPs.
Specific Aim 3 : To investigate expression and association of RAMPs with CRLR in endothelial cells and assess effects of 3 peptides on eNOS expression and phosphorylation and NO production.
Specific Aim 4 : To determine if TNF? alters expression and molecular interactions of RAMPs and CRLR and, therefore, actions of 3 peptides in VSM and endothelial cells. These findings will significantly advance our knowledge of molecular mechanisms underlying CGRP family peptide-induced vascular adaptations and offer important original insights into the possible mechanisms of vascular dysfunction in pathological pregnancies.

Public Health Relevance

Preeclampsia is a major medical disorder occurring during pregnancy and brings about more than 50,000 maternal deaths worldwide, with an estimated 45,000 deaths in the US alone. While the biological mechanisms of preeclampsia are unknown, we will investigate the molecular mechanisms of vascular adaptations that occur during pregnancy and seek understanding in how these adaptations may fail, resulting in preeclampsia. Our investigation will focus on the calcitonin gene-related peptide family and its role in these processes, with the goal of using these new mechanistic studies to develop approaches to prevent and treat preeclampsia, and to thereby reduce in women morbidity and mortality related to the cardiovascular system.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Pregnancy and Neonatology Study Section (PN)
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Ershow, Abby
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Baylor College of Medicine
Obstetrics & Gynecology
Schools of Medicine
United States
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Chauhan, Madhu; Balakrishnan, Meena; Vidaeff, Alex et al. (2016) Adrenomedullin2 (ADM2)/Intermedin (IMD): A Potential Role in the Pathophysiology of Preeclampsia. J Clin Endocrinol Metab 101:4478-4488
Gao, Haijun; Tanchico, Daren Tubianosa; Yallampalli, Uma et al. (2016) A Low-Protein Diet Enhances Angiotensin II Production in the Lung of Pregnant Rats but not Nonpregnant Rats. J Pregnancy 2016:4293431
Blesson, Chellakkan S; Schutt, Amy K; Balakrishnan, Meena P et al. (2016) Novel lean type 2 diabetic rat model using gestational low-protein programming. Am J Obstet Gynecol 214:540.e1-7
Gao, Haijun; Tanchico, Daren T; Yallampalli, Uma et al. (2015) Appetite regulation is independent of the changes in ghrelin levels in pregnant rats fed low-protein diet. Physiol Rep 3:
Chauhan, Madhu; Balakrishnan, Meena; Blesson, Chellakkan S et al. (2015) Adrenomedullin2 (ADM2)/intermedin (IMD) in rat ovary: changes in estrous cycle and pregnancy and its role in ovulation and steroidogenesis. Biol Reprod 92:39
More, Amar S; Mishra, Jay S; Hankins, Gary D V et al. (2015) Enalapril Normalizes Endothelium-Derived Hyperpolarizing Factor-Mediated Relaxation in Mesenteric Artery of Adult Hypertensive Rats Prenatally Exposed to Testosterone. Biol Reprod 92:155
Dong, Yuanlin; Betancourt, Ancizar; Chauhan, Madhu et al. (2015) Pregnancy Increases Relaxation in Human Omental Arteries to the CGRP Family of Peptides. Biol Reprod 93:134
Chauhan, Madhu; Balakrishnan, Meena; Chan, Rexanna et al. (2015) Adrenomedullin 2 (ADM2) Regulates Mucin 1 at the Maternal-Fetal Interface in Human Pregnancy. Biol Reprod 93:136
Chauhan, Madhu; Yallampalli, Uma; Banadakappa, Manu et al. (2015) Involvement of Receptor Activity-Modifying Protein 3 (RAMP3) in the Vascular Actions of Adrenomedullin in Rat Mesenteric Artery Smooth Muscle Cells. Biol Reprod 93:116
Blesson, Chellakkan S; Chinnathambi, Vijayakumar; Hankins, Gary D et al. (2015) Prenatal testosterone exposure induces hypertension in adult females via androgen receptor-dependent protein kinase Cδ-mediated mechanism. Hypertension 65:683-90

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