Factor XII and uPAR upregulate neutrophil functions to influence wound healing
Evi X. Stavrou, … , Thomas Renné, Alvin H. Schmaier
Evi X. Stavrou, … , Thomas Renné, Alvin H. Schmaier
Published March 1, 2018; First published January 29, 2018
Citation Information: J Clin Invest. 2018;128(3):944-959. https://doi.org/10.1172/JCI92880.
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Research Article Cell biology Inflammation

Factor XII and uPAR upregulate neutrophil functions to influence wound healing

Abstract

Coagulation factor XII (FXII) deficiency is associated with decreased neutrophil migration, but the mechanisms remain uncharacterized. Here, we examine how FXII contributes to the inflammatory response. In 2 models of sterile inflammation, FXII-deficient mice (F12–/–) had fewer neutrophils recruited than WT mice. We discovered that neutrophils produced a pool of FXII that is functionally distinct from hepatic-derived FXII and contributes to neutrophil trafficking at sites of inflammation. FXII signals in neutrophils through urokinase plasminogen activator receptor–mediated (uPAR-mediated) Akt2 phosphorylation at S474 (pAktS474). Downstream of pAkt2S474, FXII stimulation of neutrophils upregulated surface expression of αMβ2 integrin, increased intracellular calcium, and promoted extracellular DNA release. The sum of these activities contributed to neutrophil cell adhesion, migration, and release of neutrophil extracellular traps in a process called NETosis. Decreased neutrophil signaling in F12–/– mice resulted in less inflammation and faster wound healing. Targeting hepatic F12 with siRNA did not affect neutrophil migration, whereas WT BM transplanted into F12–/– hosts was sufficient to correct the neutrophil migration defect in F12–/– mice and restore wound inflammation. Importantly, these activities were a zymogen FXII function and independent of FXIIa and contact activation, highlighting that FXII has a sophisticated role in vivo that has not been previously appreciated.

Authors

Evi X. Stavrou, Chao Fang, Kara L. Bane, Andy T. Long, Clément Naudin, Erdem Kucukal, Agharnan Gandhi, Adina Brett-Morris, Michele M. Mumaw, Sudeh Izadmehr, Alona Merkulova, Cindy C. Reynolds, Omar Alhalabi, Lalitha Nayak, Wen-Mei Yu, Cheng-Kui Qu, Howard J. Meyerson, George R. Dubyak, Umut A. Gurkan, Marvin T. Nieman, Anirban Sen Gupta, Thomas Renné, Alvin H. Schmaier

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Figure 3

Influence of FXII on wound healing.

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Influence of FXII on wound healing. (A) Full thickness wounds from WT an...
(A) Full thickness wounds from WT and F12–/– mice (n = 12 mice/group) were imaged daily until closure using a Nikon SMZ-U dissecting microscope. Original magnification, ×1. (B) The wound area (mm2) was measured daily from day 0 until closure in WT (n = 20) and F12–/– (n = 28) mice. Wounds were considered closed when their areas relative to day 0 were less than 5%. Mean ± SEM. *P < 0.05, 2-way ANOVA. (C) H&E-stained sections from day 5 were analyzed to determine the degree of reepithelialization. Black line demarcates the total length of wound space; yellow line represents the remaining wound gap. Red arrows indicate the epithelial tongues showing ingrowing epithelium. All histologic sections were obtained using a Leica SCN 400 slide scanner equipped with a Hamamatsu line sensor color camera at ×4 magnification. Scale bar: 100 μm. (D) The percentage of reepithelialization (% wound closure) was determined using the ImageJ software and is shown for WT (n = 16) and F12–/– (n = 10) mice. Mean ± SEM. *P < 0.05, Student’s t test. (E and G) Sections from day 2 wounds were stained for NE (E) at ×20 magnification or H3Cit (G) at ×10 magnification, respectively. Scale bars: 50 μm (E); 20 μm (G). (F) NE content was determined in the wound bed immediately beneath the scab in day 2 wounds and presented as percentage of NE-stained cells to total number of cells per high-power field. WT, n = 6; F12–/–, n = 7. Mean ± SEM. *P = 0.001, Student’s t test. (H) H3Cit content of day 2 wounds is presented as total number of cells per high-power field. WT, n = 8; F12–/–, n = 15. Mean ± SEM. *P < 0.04, Student’s t test.