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Title: Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells

Abstract

Marijuana smoking is associated with a number of abnormal findings in the lungs of habitual smokers. Previous studies revealed that {delta}{sup 9}-tetrahydrocannabinol (THC) caused mitochondrial injury in primary lung epithelial cells and in the cell line, A549 [Sarafian, T. A., Kouyoumjian, S., Khoshaghideh, F., Tashkin, D. P., and Roth, M. D. (2003). Delta 9-tetrahydrocannabinol disrupts mitochondrial function and cell energetics. Am J Physiol Lung Cell Mol Physiol 284, L298-306; Sarafian, T., Habib, N., Mao, J. T., Tsu, I. H., Yamamoto, M. L., Hsu, E., Tashkin, D. P., and Roth, M. D. (2005). Gene expression changes in human small airway epithelial cells exposed to Delta9-tetrahydrocannabinol. Toxicol Lett 158, 95-107]. The role of cannabinoid receptors in this injury was unclear, as was the potential impact on cell function. In order to investigate these questions, A549 cells were engineered to over-express the type 2 cannabinoid receptor (CB2R) using a self-inactivating lentiviral vector. This transduction resulted in a 60-fold increase in CB2R mRNA relative to cells transduced with a control vector. Transduced cell lines were used to study the effects of THC on chemotactic activity and mitochondrial function. Chemotaxis in response to a 10% serum gradient was suppressed in a concentration-dependent manner by exposuremore » to THC. CB2R-transduced cells exhibited less intrinsic chemotactic activity (p < 0.05) and were 80- to 100-fold more sensitive to the inhibitory effects of THC. Studies using SR144528, a selective CB2R antagonist, verified that these effects were mediated by the CB2R. Marijuana smoke extract, but not smoke extracts from tobacco or placebo marijuana cigarettes, reproduced these effects (p < 0.05). THC decreased ATP level and mitochondrial membrane potential ({psi}{sub m}) in both control and CB2R-transduced cells. However, these decreases did not play a significant role in chemotaxis inhibition since cyclosporine A, which protected against ATP loss, did not increase cell migration. Moreover, CB2R-transduced cells displayed higher {psi}{sub m} than did control cells. Since both {psi}{sub m} and chemotaxis are regulated by intracellular signaling, we investigated the effects of THC on the activation of multiple signaling pathways. Serum exposure activated several signaling events of which phosphorylation of I{kappa}B-{alpha} and JNK was regulated in a CB2R- and THC-dependent manner. We conclude that airway epithelial cells are sensitive to both CB2R-dependent and independent effects mediated by THC.« less

Authors:
 [1]; ;  [2];  [3];  [2];  [4];  [2];  [5]; ;  [2];  [2];  [6]
  1. Division of Pulmonary and Critical Care, Department of Medicine, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095 (United States), E-mail: tsarafian@mednet.ucla.edu
  2. Division of Pulmonary and Critical Care, Department of Medicine, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095 (United States)
  3. Interdepartmental Program in Molecular Toxicology, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095 (United States)
  4. Division of Gastroenterology, Department of Medicine, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095 (United States)
  5. Department of Biostatistics, UCLA School of Public Health, 37-131 CHS, Los Angeles, CA 90095 (United States)
  6. (United States)
Publication Date:
OSTI Identifier:
21140952
Resource Type:
Journal Article
Resource Relation:
Journal Name: Toxicology and Applied Pharmacology; Journal Volume: 231; Journal Issue: 3; Other Information: DOI: 10.1016/j.taap.2008.05.001; PII: S0041-008X(08)00202-0; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ATP; CYCLOSPORINE; INJURIES; LUNGS; MARIHUANA; MITOCHONDRIA; PHOSPHORYLATION; RECEPTORS; RESPIRATORY TRACT CELLS; SMOKES; TOBACCO

Citation Formats

Sarafian, Theodore, Montes, Cindy, Harui, Airi, Beedanagari, Sudheer R., Kiertscher, Sylvia, Stripecke, Renata, Hossepian, Derik, Kitchen, Christina, Kern, Rita, Belperio, John, Roth, Michael D., and Interdepartmental Program in Molecular Toxicology, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095. Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells. United States: N. p., 2008. Web. doi:10.1016/j.taap.2008.05.001.
Sarafian, Theodore, Montes, Cindy, Harui, Airi, Beedanagari, Sudheer R., Kiertscher, Sylvia, Stripecke, Renata, Hossepian, Derik, Kitchen, Christina, Kern, Rita, Belperio, John, Roth, Michael D., & Interdepartmental Program in Molecular Toxicology, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095. Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells. United States. doi:10.1016/j.taap.2008.05.001.
Sarafian, Theodore, Montes, Cindy, Harui, Airi, Beedanagari, Sudheer R., Kiertscher, Sylvia, Stripecke, Renata, Hossepian, Derik, Kitchen, Christina, Kern, Rita, Belperio, John, Roth, Michael D., and Interdepartmental Program in Molecular Toxicology, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095. Mon . "Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells". United States. doi:10.1016/j.taap.2008.05.001.
@article{osti_21140952,
title = {Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells},
author = {Sarafian, Theodore and Montes, Cindy and Harui, Airi and Beedanagari, Sudheer R. and Kiertscher, Sylvia and Stripecke, Renata and Hossepian, Derik and Kitchen, Christina and Kern, Rita and Belperio, John and Roth, Michael D. and Interdepartmental Program in Molecular Toxicology, David Geffen School of Medicine at UCLA, 37-131 CHS, Los Angeles, CA 90095},
abstractNote = {Marijuana smoking is associated with a number of abnormal findings in the lungs of habitual smokers. Previous studies revealed that {delta}{sup 9}-tetrahydrocannabinol (THC) caused mitochondrial injury in primary lung epithelial cells and in the cell line, A549 [Sarafian, T. A., Kouyoumjian, S., Khoshaghideh, F., Tashkin, D. P., and Roth, M. D. (2003). Delta 9-tetrahydrocannabinol disrupts mitochondrial function and cell energetics. Am J Physiol Lung Cell Mol Physiol 284, L298-306; Sarafian, T., Habib, N., Mao, J. T., Tsu, I. H., Yamamoto, M. L., Hsu, E., Tashkin, D. P., and Roth, M. D. (2005). Gene expression changes in human small airway epithelial cells exposed to Delta9-tetrahydrocannabinol. Toxicol Lett 158, 95-107]. The role of cannabinoid receptors in this injury was unclear, as was the potential impact on cell function. In order to investigate these questions, A549 cells were engineered to over-express the type 2 cannabinoid receptor (CB2R) using a self-inactivating lentiviral vector. This transduction resulted in a 60-fold increase in CB2R mRNA relative to cells transduced with a control vector. Transduced cell lines were used to study the effects of THC on chemotactic activity and mitochondrial function. Chemotaxis in response to a 10% serum gradient was suppressed in a concentration-dependent manner by exposure to THC. CB2R-transduced cells exhibited less intrinsic chemotactic activity (p < 0.05) and were 80- to 100-fold more sensitive to the inhibitory effects of THC. Studies using SR144528, a selective CB2R antagonist, verified that these effects were mediated by the CB2R. Marijuana smoke extract, but not smoke extracts from tobacco or placebo marijuana cigarettes, reproduced these effects (p < 0.05). THC decreased ATP level and mitochondrial membrane potential ({psi}{sub m}) in both control and CB2R-transduced cells. However, these decreases did not play a significant role in chemotaxis inhibition since cyclosporine A, which protected against ATP loss, did not increase cell migration. Moreover, CB2R-transduced cells displayed higher {psi}{sub m} than did control cells. Since both {psi}{sub m} and chemotaxis are regulated by intracellular signaling, we investigated the effects of THC on the activation of multiple signaling pathways. Serum exposure activated several signaling events of which phosphorylation of I{kappa}B-{alpha} and JNK was regulated in a CB2R- and THC-dependent manner. We conclude that airway epithelial cells are sensitive to both CB2R-dependent and independent effects mediated by THC.},
doi = {10.1016/j.taap.2008.05.001},
journal = {Toxicology and Applied Pharmacology},
number = 3,
volume = 231,
place = {United States},
year = {Mon Sep 15 00:00:00 EDT 2008},
month = {Mon Sep 15 00:00:00 EDT 2008}
}