Our laboratory previously discovered a central role for ceramide in the development of emphysema. We demonstrated that ceramide is a proximal hub of amplification for apoptosis, oxidative stress, and for its own synthesis, and is both necessary and sufficient to induce airspace enlargement and functional decreases of lung elastance, fundamental characteristics of emphysema. In this application we address the novel concept that cigarette smoke (CS) exposure disrupts sphingolipid homeostasis in the lung to generate distinct acute and chronic ceramide responses, responsible for the death of structural alveolar epithelial and endothelial cells, inhibition of clearance of apoptotic cells by alveolar macrophages, and impairment of cell repair that sustain an irreversible lung destruction in emphysema. We hypothesize that CS-induced ceramides trigger alveolar cell death, impair proper removal of apoptotic bodies, and disrupt cell repair due to sequential activation of acid sphingomyelinase followed by de novo ceramide synthesis. We will test this hypothesis by using transgenic in vivo approaches complemented with pharmacological inhibition of target enzymes and by assessing structural and functional endpoints that characterize cigarette smoke-induced emphysema. Sphingolipid measurements and their effect on alveolar apoptosis and clearance of apoptotic cells will be studied by tandem mass spectrometry and intravital/time-lapse two-photon microscopy, respectively.
The specific aims are: 1) To determine that the CS-activated acid sphingomyelinase triggers alveolar cell apoptosis and causes airspace enlargement in mice. 2) To establish that CS and paracellular ceramides activate the de novo pathway in alveolar macrophages causing inhibition of apoptotic body removal. 3) To elucidate if the paracrine activation of de novo ceramide synthesis causes alveolar cell apoptosis and decreased lung repair by CS. Our experimental questions and approach will address fundamental questions of emphysema pathogenesis and will provide the rationale and basis for developing a therapeutic strategy for patients with COPD.

Public Health Relevance

We propose to renew our studies on the role of ceramides in emphysema with a new investigation to identify specific regulatory and amplifying sphingolipid pathways triggered by progressive cigarette smoke exposure. Ceramide molecular species are differentially regulated via either synthesis or metabolism through enzymatic pathways activated in distinct cellular subcompartments. Our work will address fundamental questions of emphysema pathogenesis by defining processes that occur in the early stages of CS exposure and mechanistically linking them to the development of chronic injury. Our results will provide the rationale and basis for developing a therapeutic strategy for patients with COPD, will define several sphingolipids as sensor molecules of CS-induced lung tissue damage, and will link alveolar epithelial and endothelial cell damage to paracellular releases of ceramides which may lead paracrine and systemic COPD manifestations.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL077328-08
Application #
8450855
Study Section
Lung Injury, Repair, and Remodeling Study Section (LIRR)
Program Officer
Postow, Lisa
Project Start
2004-07-01
Project End
2016-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
8
Fiscal Year
2013
Total Cost
$432,917
Indirect Cost
$141,605
Name
Indiana University-Purdue University at Indianapolis
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
603007902
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Barwinska, Daria; Oueini, Houssam; Poirier, Christophe et al. (2018) AMD3100 ameliorates cigarette smoke-induced emphysema-like manifestations in mice. Am J Physiol Lung Cell Mol Physiol 315:L382-L386
Justice, Matthew J; Bronova, Irina; Schweitzer, Kelly S et al. (2018) Inhibition of acid sphingomyelinase disrupts LYNUS signaling and triggers autophagy. J Lipid Res 59:596-606
Frump, Andrea L; Selej, Mona; Wood, Jordan A et al. (2018) Hypoxia Upregulates Estrogen Receptor ? in Pulmonary Artery Endothelial Cells in a HIF-1?-Dependent Manner. Am J Respir Cell Mol Biol 59:114-126
Mizumura, Kenji; Justice, Matthew J; Schweitzer, Kelly S et al. (2018) Sphingolipid regulation of lung epithelial cell mitophagy and necroptosis during cigarette smoke exposure. FASEB J 32:1880-1890
Suratt, Benjamin T; Ubags, Niki D J; Rastogi, Deepa et al. (2017) An Official American Thoracic Society Workshop Report: Obesity and Metabolism. An Emerging Frontier in Lung Health and Disease. Ann Am Thorac Soc 14:1050-1059
Ni, Kevin; Serban, Karina A; Batra, Chanan et al. (2016) Alpha-1 Antitrypsin Investigations Using Animal Models of Emphysema. Ann Am Thorac Soc 13 Suppl 4:S311-6
Klionsky, Daniel J (see original citation for additional authors) (2016) Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition). Autophagy 12:1-222
Serban, Karina A; Rezania, Samin; Petrusca, Daniela N et al. (2016) Structural and functional characterization of endothelial microparticles released by cigarette smoke. Sci Rep 6:31596
Petrache, Irina; Berdyshev, Evgeny V (2016) Ceramide Signaling and Metabolism in Pathophysiological States of the Lung. Annu Rev Physiol 78:463-80
Bowler, Russell P; Jacobson, Sean; Cruickshank, Charmion et al. (2015) Plasma sphingolipids associated with chronic obstructive pulmonary disease phenotypes. Am J Respir Crit Care Med 191:275-84

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