Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hypertens. May 10, 2019; 9(2): 17-29
Published online May 10, 2019. doi: 10.5494/wjh.v9.i2.17
Loss of cavin1 and expression of p-caveolin-1 in pulmonary hypertension: Possible role in neointima formation
Jing Huang, Rajamma Mathew
Jing Huang, Rajamma Mathew, Department of Pediatrics, New York Medical College, Valhalla, NY 10595, United States
Rajamma Mathew, Department of Physiology, New York Medical College, Valhalla, NY 10595, United States
Author contributions: Mathew R designed the study, and wrote the paper; Huang J performed the majority of the experiments, and participated in data collection, analysis and discussion.
Supported by: Supported in part by Cardiovascular Medical Research and Education Fund .
Institutional review board statement: All animal experiments were conducted in accordance with the PHS policy and the NIH Guide for the Care and Use of Laboratory Animals.
Institutional animal care and use committee statement: All animal studies were approved by the New York Medical College’s Institutional Care and Use of Animals.
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Rajamma Mathew MD, Professor, Department of Pediatrics and Physiology, New York Medical College, 15 Dana Road, Rm A11, Basic science Building, Valhalla, NY 10595, United States.
Telephone: +1-914-5944750 Fax: +1-914-5944655
Received: October 11, 2018
Peer-review started: October 12, 2018
First decision: December 18, 2019
Revised: January 8, 2019
Accepted: March 12, 2019
Article in press: March 12, 2019
Published online: May 10, 2019

Pulmonary hypertension (PH) is a progressive disease with a high morbidity and mortality rate; and neointima formation leads to the irreversibility of the disease. We have previously reported that in rats, monocrotaline (MCT) injection leads to progressive disruption of endothelial cells (EC), and endothelial caveolin-1 (cav-1) loss, accompanied by the activation of pro-proliferative pathways leading to PH. Four weeks post-MCT, extensive endothelial cav-1 loss is associated with increased cav-1 expression in smooth muscle cells (SMC). Exposing the MCT-treated rats to hypoxia hastens the disease process; and at 4 wk, neointimal lesions and occlusion of the small arteries are observed.


To identify the alterations that occur during the progression of PH that lead to neointima formation.


Male Sprague-Dawley rats (150-175 g) were divided in 4 groups (n = 6-8 per group): controls (C); MCT (M, a single sc injection 40 mg/kg); Hypoxia (H, hypobaric hypoxia); MCT + hypoxia (M+H, MCT-injected rats subjected to hypobaric hypoxia starting on day1). Four weeks later, right ventricular systolic pressure (RVSP), right ventricular hypertrophy (RVH), lung histology, and cav-1 localization using immunofluorescence technique were analyzed. In addition, the expression of cav-1, tyrosine 14 phosphorylated cav-1 (p-cav-1), caveolin-2 (cav-2), cavin-1, vascular endothelial cadherin (VE-Cad) and p-ERK1/2 in the lungs were examined, and the results were compared with the controls.


Significant PH and right ventricular hypertrophy were present in M and H groups [RVSP, mmHg, M 54±5*, H 45±2*, vs C 20±1, P < 0.05; RVH, RV/LV ratio M 0.57±0.02*, H 0.50±0.03*, vs C 0.23±0.007, P < 0.05]; with a further increase in M+H group [RVSP 69±9 mmHg, RV/LV 0.59±0.01 P < 0.05 vs M and H]. All experimental groups revealed medial hypertrophy; but only M+H group exhibited small occluded arteries and neointimal lesions. Immunofluorescence studies revealed endothelial cav-1 loss and increased cav-1 expression in SMC in M group; however, the total cav-1 level in the lungs remained low. In the M+H group, significant endothelial cav-1 loss was associated with increasing expression of cav-1 in SMC; resulting in near normalization of cav-1 levels in the lungs [cav-1, expressed as % control, C 100±0, M 22±4*, H 96±7, M+H 77±6, * = P < 0.05 vs C]. The expression of p-cav-1 was observed in M and M+H groups [M 314±4%, M+H 255±22% P < 0.05 vs C]. Significant loss of cav-2 [% control, C 100±0, M 15±1.4*, H 97±7, M+H 15±2*; M and M+H vs C, * = P < 0.05], cavin-1 [% control, C 100±0, M 20±3*, H 117±7, M+H 20±4*; M and M+H vs C, P < 0.05] and VE-Cad [% control, C 100±0, M 17±4*, H 96±9, M+H 8±3*; M and M+H vs C, P < 0.05] was present in M and M+H groups, confirming extensive disruption of EC. Hypoxia alone did not alter the expression of cav-1 or cav-1 related proteins. Expression of p-ERK1/2 was increased in all 3 PH groups [%control, C 100±0, M 284±23*, H 254±25*, M+H 270±17*; * = P < 0.05 vs C].


Both cavin-1 loss and p-cav-1 expression are known to facilitate cell migration; thus, these alterations may in part play a role in neointima formation in PH.

Keywords: Caveolin-1, Cavin-1, Neointima, Phospho-caveolin1, Pulmonary hypertension

Core tip: Neointima leads to irreversible pulmonary hypertension (PH). Subjecting the monocrotaline (MCT)-injected rats to hypoxia accelerates the disease process; by 4 wks, neointima develops in arteries with extensive disruption of endothelial cells (EC), loss of endothelial caveolin-1 (cav-1), and enhanced cav-1 expression in smooth muscle cells. In addition, the MCT and MCT+ hypoxia groups exhibit significant loss of cavin-1 and the presence of tyrosine phosphorylated cav-1, which may facilitate cell migration and neointima formation. Hypoxia-induced PH does not exhibit EC disruption or alterations in cav-1 expression. Thus, EC integrity may determine the reversibility or irreversibility of PH.