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 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 10

The influence of BM transplantation on inflammation and wound healing.

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The influence of BM transplantation on inflammation and wound healing. (...
(A) PEC number after TG-induced peritonitis in WT or KO (F12–/–) hosts after WT or KO BM transplantation (n = 11–13 transplants/condition). Mean ± SEM. *P < 0.0004 by 1-way ANOVA. (B) Flow cytometry of murine peritoneal lavage fluid 4 hours following TG-induced peritonitis in WT or KO BM–transplanted hosts. PEC were labeled with PE-conjugated anti-CD11b and PerCPCy 5.5–conjugated anti–F4-80 antibodies. Circles indicate the neutrophil subpopulation (CD11b-positive, F4-80–negative cells). The figure shows a representative flow cytogram of n = 4 transplanted animals in each group. (C) NE and pAkt coimmunostaining from day 2 wounds of WT and (D) day 2 wounds of F12–/– BM chimeras. Representative images of n = 4 wounds in each group. Left panels in C and D. Scale bars: 50 μm (left panels); 100 μm (right panels). Original magnification, ×4 (left panels); ×20 (right panels). (E) Number of Ly6G cells/high-power field in day 2 wounds of WT and F12–/– chimeras. n = 6–9 transplants/condition. Mean ± SEM. *P < 0.007, 1-way ANOVA. (F) H&E-stained sections in day 5 wounds of WT and F12–/– BM chimeras. Representative images of n = 6–9 wounds in each group of transplanted animals. Original magnification, ×4. Black lines demarcate the total length of original wound; yellow line represents the remaining wound gap. Red arrows represent the ingrowing epithelial tongues, closing wound. In photographs in which a red asterisk is seen, the wound gap is 0, indicating that the wound has completely reepithelialized. Scale bars: 100 μm. Histologic sections were obtained using a Leica SCN 400 slide scanner equipped with a Hamamatsu line sensor color camera. Analysis was performed using ImageJ software. (G) Wound closure in WT and F12–/– BM chimeras, n = 6–9 wounds/group. Mean ± SEM. *P = 0.0004, 1-way ANOVA.