Lovastatin Enhances Clearance of Apoptotic Cells (Efferocytosis) with Implications for Chronic Obstructive Pulmonary Disease

• Published in: Journal of Immunology Vol. 176; no. 12; pp. 7657 - 7665
• Main Authors: Morimoto, Konosuke, Janssen, William J, Fessler, Michael B, McPhillips, Kathleen A, Borges, Valeria M, Bowler, Russell P, Xiao, Yi-Qun, Kench, Jennifer A, Henson, Peter M, Vandivier, R. William
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15.06.2006
• Subjects: Animals; Apoptosis - drug effects; Apoptosis - physiology; CD36 Antigens - biosynthesis; Cells, Cultured; Female; Humans; Hydroxymethylglutaryl CoA Reductases - physiology; Hydroxymethylglutaryl-CoA Reductase Inhibitors - pharmacology; Jurkat Cells; Lovastatin - administration & dosage; Lovastatin - pharmacology; Lung - cytology; Lung - drug effects; Lung - enzymology; Lysophospholipids - antagonists & inhibitors; Lysophospholipids - pharmacology; Macrophages - cytology; Macrophages - drug effects; Macrophages, Alveolar - cytology; Macrophages, Alveolar - drug effects; Macrophages, Alveolar - enzymology; Membrane Proteins - antagonists & inhibitors; Membrane Proteins - metabolism; Mice; Mice, Inbred ICR; Monocytes - cytology; Phagocytosis - physiology; Protein Prenylation - drug effects; Protein Prenylation - physiology; Pulmonary Disease, Chronic Obstructive - drug therapy; Pulmonary Disease, Chronic Obstructive - enzymology; Pulmonary Disease, Chronic Obstructive - pathology; rac1 GTP-Binding Protein - antagonists & inhibitors; rac1 GTP-Binding Protein - metabolism; rhoA GTP-Binding Protein - antagonists & inhibitors; rhoA GTP-Binding Protein - metabolism
• ISSN: 0022-1767; 1550-6606; 1365-2567
• DOI: 10.4049/jimmunol.176.12.7657

Statins are potent, cholesterol-lowering agents with newly appreciated, broad anti-inflammatory properties, largely based upon their ability to block the prenylation of Rho GTPases, including RhoA. Because phagocytosis of apoptotic cells (efferocytosis) is a pivotal regulator of inflammation, which is inhibited by RhoA, we sought to determine whether statins enhanced efferocytosis. The effect of lovastatin on efferocytosis was investigated in primary human macrophages, in the murine lung, and in human alveolar macrophages taken from patients with chronic obstructive pulmonary disease. In this study, we show that lovastatin increased efferocytosis in vitro in an 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase-dependent manner. Lovastatin acted by inhibiting both geranylgeranylation and farnesylation, and not by altering expression of key uptake receptors or by increasing binding of apoptotic cells to phagocytes. Lovastatin appeared to exert its positive effect on efferocytosis by inhibiting RhoA, because it 1) decreased membrane localization of RhoA, to a greater extent than Rac-1, and 2) prevented impaired efferocytosis by lysophosphatidic acid, a potent inducer of RhoA. Finally, lovastatin increased efferocytosis in the naive murine lung and ex vivo in chronic obstructive pulmonary disease alveolar macrophages in an HMG-CoA reductase-dependent manner. These findings indicate that statins enhance efferocytosis in vitro and in vivo, and suggest that they may play an important therapeutic role in diseases where efferocytosis is impaired and inflammation is dysregulated.