Lovastatin Inhibits Low Molecular Weight Hyaluronan Induced Chemokine Expression via LFA-1 and Decreases Bleomycin-Induced Pulmonary Fibrosis

BACKGROUND: Lovastatin has a unique ability to bind Leukocyte Function Antigen-1 (LFA-1), an integrin necessary for the full expression of inflammatory cytokines induced by the low molecular weight form of the extracellular matrix glycosaminoglycan hyaluronan (LMW HA). We hypothesized that lovastatin could inhibit LMW HA inflammatory signals via interaction with LFA-1, and attenuate bleomycin induced pulmonary fibrosis. METHODS: We evaluated the effects of lovastatin, pravastatin, LFA-1 blocking antibodies, and a novel LFA-1 inhibitor LFA 878 on LMW HA induced cytokine production in alveolar macrophages. We evaluated the effect of lovastatin in a bleomycin model of lung injury. RESULTS: Lovastatin immediately inhibited the LMW HA induced cytokine MIP 1-α (p=0.001) independent of HMG CoA reductase. Pravastatin showed no inhibitory profile when administered simultaneously with LMW HA. LFA-1 blocking antibodies and the small molecule statin derivative LFA 878 showed an inhibitory profile similar to lovastatin. Lovastatin showed decreased fibrosis on histopathology and improved survival at day 14, with a decrease in fibrocytes noted at day 8. CONCLUSION: Lovastatin and LFA 878 inhibit LMW HA inflammatory signaling independent of HMG-CoA decreasing the chemotactic cytokine MIP 1-α. Lovastatin treatment improves survival in bleomycin lung injury with decreased fibrocytes and fibrosis.