Proteinase 3 and neutrophil elastase enhance inflammation in mice by inactivating antiinflammatory progranulin
Kai Kessenbrock, … , Reinhard Fässler, Dieter E. Jenne
Kai Kessenbrock, … , Reinhard Fässler, Dieter E. Jenne
Published June 20, 2008
Citation Information: J Clin Invest. 2008;118(7):2438-2447. https://doi.org/10.1172/JCI34694.
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Research Article Inflammation

Proteinase 3 and neutrophil elastase enhance inflammation in mice by inactivating antiinflammatory progranulin

Abstract

Neutrophil granulocytes form the body’s first line of antibacterial defense, but they also contribute to tissue injury and noninfectious, chronic inflammation. Proteinase 3 (PR3) and neutrophil elastase (NE) are 2 abundant neutrophil serine proteases implicated in antimicrobial defense with overlapping and potentially redundant substrate specificity. Here, we unraveled a cooperative role for PR3 and NE in neutrophil activation and noninfectious inflammation in vivo, which we believe to be novel. Mice lacking both PR3 and NE demonstrated strongly diminished immune complex–mediated (IC-mediated) neutrophil infiltration in vivo as well as reduced activation of isolated neutrophils by ICs in vitro. In contrast, in mice lacking just NE, neutrophil recruitment to ICs was only marginally impaired. The defects in mice lacking both PR3 and NE were directly linked to the accumulation of antiinflammatory progranulin (PGRN). Both PR3 and NE cleaved PGRN in vitro and during neutrophil activation and inflammation in vivo. Local administration of recombinant PGRN potently inhibited neutrophilic inflammation in vivo, demonstrating that PGRN represents a crucial inflammation-suppressing mediator. We conclude that PR3 and NE enhance neutrophil-dependent inflammation by eliminating the local antiinflammatory activity of PGRN. Our results support the use of serine protease inhibitors as antiinflammatory agents.

Authors

Kai Kessenbrock, Leopold Fröhlich, Michael Sixt, Tim Lämmermann, Heiko Pfister, Andrew Bateman, Azzaq Belaaouaj, Johannes Ring, Markus Ollert, Reinhard Fässler, Dieter E. Jenne

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Figure 2

PR3 and NE are not principally required for neutrophil extravasation and interstitial migration.

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PR3 and NE are not principally required for neutrophil extravasation and...
(A and B) Phorbol ester–treated ear tissues of WT and Prtn3–/–Ela2–/– mice were immunostained for laminin (LN; green) to visualize EBM and Gr-1 (red) to identify neutrophils. Lesions were examined 4 h after stimulus application by fluorescence microscopy as described in Methods. (A) Representative images of tissue from WT and Prtn3–/–Ela2–/– mice. Both genotypes developed strong and widespread neutrophil infiltrations. (B) Higher-magnification images of boxed regions in A. Prtn3–/–Ela2–/– neutrophils showed no retention at the EBM. Scale bars: 200 μm (A); 25 μm (B). (C) Overall neutrophil infiltrates were quantified as the percentage of Gr-1–positive cells per microscopic field. Data are mean ± SEM. Intravascular cells were excluded. No significant difference between WT and Prtn3–/–Ela2–/– mice was found (P = 0.63). In vitro migration of WT and Prtn3–/–Ela2–/– neutrophils directed by C5a through 3-dimensional collagen matrices was analyzed by time-lapse video microscopy (see Supplemental Video 1). (D) The tracks of WT (n = 41) and Prtn3–/–Ela2–/– (n = 42) neutrophils are shown, and the factor for directionality ± SEM is indicated. No impairment was observed regarding chemotactic directionality of Prtn3–/–Ela2–/– versus WT neutrophils (P = 0.19). (E) Velocities of single cells (individual points) were calculated and averaged (red bar). Prtn3–/–Ela2–/– neutrophils showed no significant difference versus WT cells (P = 0.30).