Elastin fragments drive disease progression in a murine model of emphysema
A. McGarry Houghton, … , obert M. Senior,, Steven D. Shapiro
A. McGarry Houghton, … , obert M. Senior,, Steven D. Shapiro
Published March 1, 2006
Citation Information: J Clin Invest. 2006;116(3):753-759. https://doi.org/10.1172/JCI25617.
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Research Article Inflammation

Elastin fragments drive disease progression in a murine model of emphysema

Abstract

Mice lacking macrophage elastase (matrix metalloproteinase-12, or MMP-12) were previously shown to be protected from the development of cigarette smoke–induced emphysema and from the accumulation of lung macrophages normally induced by chronic exposure to cigarette smoke. To determine the basis for macrophage accumulation in experimental emphysema, we now show that bronchoalveolar lavage fluid from WT smoke-exposed animals contained chemotactic activity for monocytes in vitro that was absent in lavage fluid from macrophage elastase–deficient mice. Fractionation of the bronchoalveolar lavage fluid demonstrated the presence of elastin fragments only in the fractions containing chemotactic activity. An mAb against elastin fragments eliminated both the in vitro chemotactic activity and cigarette smoke–induced monocyte recruitment to the lung in vivo. Porcine pancreatic elastase was used to recruit monocytes to the lung and to generate emphysema. Elastin fragment antagonism in this model abrogated both macrophage accumulation and airspace enlargement.

Authors

A. McGarry Houghton, Pablo A. Quintero, David L. Perkins, Dale K. Kobayashi, Diane G. Kelley, Luiz A. Marconcini, Robert P. Mecham, obert M. Senior,, Steven D. Shapiro

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Figure 1

EFs display monocyte chemotactic activity.

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EFs display monocyte chemotactic activity. Human monocytes were isolated...
Human monocytes were isolated by elutriation, and chemotaxis assays were performed in a modified Boyden chamber. (A) BALF from smoke-exposed mice (2 months) was used as the chemoattractant. Data are from a representative experiment performed in triplicate. Net monocyte movement = total monocytes – media control (= 40). Bars represent SEM. *P < 0.01 vs. control. (B) The BAL samples from MMP-12+/+ and MMP-12–/– mice were subjected to gel filtration. The fractions were tested for monocyte chemotactic activity (control activity with PBS alone = 0). (C) Western blot was performed against gel filtration fractions (nos. 11 and 37 shown here) using a polyclonal anti-elastin antibody. A 45-kDa fragment in MMP-12+/+ active fractions was detected. (D) The assays of monocyte chemotaxis were repeated using lung homogenates from mice exposed to smoke for 2 months as the chemoattractant. BA4 and IgG1 preimmune antibodies were used at a concentration of 50 nM. Data are from a representative experiment performed in triplicate. Net monocyte movement per high-powered field = total monocytes – media control (= 46). Bars represent SEM. *P < 0.01 vs. control. hpf, high-powered field; NS, non–smoke exposed; Sm, smoke exposed.