This competitive renewal requests funding for a program that has been supported by NIH for the past 19 years. The program has demonstrated that ischemia in the lung leads to a reproducible response due to altered mechanotransduction and is characterized by endothelial cell membrane depolarization, activation of cell membrane associated NADPH oxidase (NOX2), generation of reactive oxygen species (ROS), activation of transcription factors (NF(B, AP-1, and others), and endothelial cell proliferation. We postulate that this sequence of events represents a signaling response leading to angiogenesis as a compensatory effort to restore blood flow. Intracellular release of Fe++ in the presence of increased ROS generation can result in oxidation of lipid and protein components leading to cell injury. Evidence of oxidative stress was increased lipid oxidation products and increased protein carbonyls. Thus, this mechanism results in lung signaling but can contribute to pulmonary pathophysiology. This project has made the seminal finding that the syndrome of ischemia-mediated ROS generation can be reproduced with endothelial cells in vitro provided that they have been flow adapted. We propose 4 specific aims to investigate: 1) the role of caveolae in sensing altered shear during ischemia;2) the pathway for linkage between caveolae and endothelial cell depolarization;3) the mechanism for ROS generation with ischemia and 4) the role of PI3Kinase/Akt in linking membrane depolarization with ROS production. The studies will utilize the isolated perfused mouse lung preparation, isolated mouse pulmonary microvascular endothelial cells that have been flow adapted in vitro and hind limb ischemia in vivo. These studies will provide additional insights into a novel mechanism for initiation of endothelial ROS generation and subsequent cell signaling. The proposed mechanism is of potential importance as a source of ROS leading to acute lung injury in association with focal vascular obstruction. PROJECT NARRATIVE: The pulmonary endothelium generates reactive oxygen species (ROS) when the blood flow through a vessel is interrupted due to various pathological conditions. Here we propose to identify the elements on the endothelium that lead to assembly of the reactive oxygen species generating machinery. ROS generation with stop of flow causes cell proliferation;thus understanding the mechanism by which these elements respond to stop of flow to produce ROS can help toward strategies to manipulate cell growth and proliferation in obstructed blood vessels.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Lung Injury, Repair, and Remodeling Study Section (LIRR)
Program Officer
Harabin, Andrea L
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Pennsylvania
Schools of Medicine
United States
Zip Code
Chatterjee, Shampa; Fujiwara, Keigi; Pérez, Néstor Gustavo et al. (2015) Mechanosignaling in the vasculature: emerging concepts in sensing, transduction and physiological responses. Am J Physiol Heart Circ Physiol 308:H1451-62
Chatterjee, Shampa; Nieman, Gary F; Christie, Jason D et al. (2014) Shear stress-related mechanosignaling with lung ischemia: lessons from basic research can inform lung transplantation. Am J Physiol Lung Cell Mol Physiol 307:L668-80
Chowdhury, Ibrul; Fisher, Aron B; Christofidou-Solomidou, Melpo et al. (2014) Keratinocyte growth factor and glucocorticoid induction of human peroxiredoxin 6 gene expression occur by independent mechanisms that are synergistic. Antioxid Redox Signal 20:391-402
Browning, Elizabeth; Wang, Hui; Hong, Nankang et al. (2014) Mechanotransduction drives post ischemic revascularization through K(ATP) channel closure and production of reactive oxygen species. Antioxid Redox Signal 20:872-86
Orndorff, Rebecca L; Hong, Nankang; Yu, Kevin et al. (2014) NOX2 in lung inflammation: quantum dot based in situ imaging of NOX2-mediated expression of vascular cell adhesion molecule-1. Am J Physiol Lung Cell Mol Physiol 306:L260-8
Noel, John; Wang, Hui; Hong, Nankang et al. (2013) PECAM-1 and caveolae form the mechanosensing complex necessary for NOX2 activation and angiogenic signaling with stopped flow in pulmonary endothelium. Am J Physiol Lung Cell Mol Physiol 305:L805-18
Chatterjee, Shampa; Browning, Elizabeth A; Hong, NanKang et al. (2012) Membrane depolarization is the trigger for PI3K/Akt activation and leads to the generation of ROS. Am J Physiol Heart Circ Physiol 302:H105-14
Browning, Elizabeth A; Chatterjee, Shampa; Fisher, Aron B (2012) Stop the flow: a paradigm for cell signaling mediated by reactive oxygen species in the pulmonary endothelium. Annu Rev Physiol 74:403-24
Lien, Yu-Chin; Feinstein, Sheldon I; Dodia, Chandra et al. (2012) The roles of peroxidase and phospholipase A2 activities of peroxiredoxin 6 in protecting pulmonary microvascular endothelial cells against peroxidative stress. Antioxid Redox Signal 16:440-51
Sorokina, Elena M; Feinstein, Sheldon I; Zhou, Suiping et al. (2011) Intracellular targeting of peroxiredoxin 6 to lysosomal organelles requires MAPK activity and binding to 14-3-3?. Am J Physiol Cell Physiol 300:C1430-41

Showing the most recent 10 out of 18 publications