MIF but not MIF-2 recruits inflammatory macrophages in an experimental polymicrobial sepsis model
Pathricia Veronica Tilstam, … , Günter Fingerle-Rowson, Richard Bucala
Pathricia Veronica Tilstam, … , Günter Fingerle-Rowson, Richard Bucala
Published December 1, 2021
Citation Information: J Clin Invest. 2021;131(23):e127171. https://doi.org/10.1172/JCI127171.
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Research Article Immunology Inflammation

MIF but not MIF-2 recruits inflammatory macrophages in an experimental polymicrobial sepsis model

Abstract

Excessive inflammation drives the progression from sepsis to septic shock. Macrophage migration inhibitory factor (MIF) is of interest because MIF promoter polymorphisms predict mortality in different infections, and anti-MIF antibody improves survival in experimental models when administered 8 hours after infectious insult. The recent description of a second MIF superfamily member, D-dopachrome tautomerase (D-DT/MIF-2), prompted closer investigation of MIF-dependent responses. We subjected Mif–/– and Mif-2–/– mice to polymicrobial sepsis and observed a survival benefit with Mif but not Mif-2 deficiency. Survival was associated with reduced numbers of small peritoneal macrophages (SPMs) that, in contrast to large peritoneal macrophages (LPMs), were recruited into the peritoneal cavity. LPMs produced higher quantities of MIF than SPMs, but SPMs expressed higher levels of inflammatory cytokines and the MIF receptors CD74 and CXCR2. Adoptive transfer of WT SPMs into Mif–/– hosts reduced the protective effect of Mif deficiency in polymicrobial sepsis. Notably, MIF-2 lacks the pseudo-(E)LR motif present in MIF that mediates CXCR2 engagement and SPM migration, supporting a specific role for MIF in the recruitment and accumulation of inflammatory SPMs.

Authors

Pathricia Veronica Tilstam, Wibke Schulte, Thomas Holowka, Bong-Sung Kim, Jessica Nouws, Maor Sauler, Marta Piecychna, Georgios Pantouris, Elias Lolis, Lin Leng, Jürgen Bernhagen, Günter Fingerle-Rowson, Richard Bucala

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Figure 8

CCL2 and MIF regulation of LPMs and SPMs during i.p. sepsis.

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CCL2 and MIF regulation of LPMs and SPMs during i.p. sepsis. (A) Impact ...
(A) Impact of CCL2 antagonism (R&D Systems, AF-479-NA, 25 μg/kg, i.p.) and CXCR2 antagonism (SB225002, 10 mg/kg, i.p.) on SPM migration into LPS-conditioned peritonea (LPS 12.5 mg/kg, i.p., 2 hours previously). Data are from n = 11 to 19 animals (1-way ANOVA with Tukey’s multiple-comparison test). (B) Quantitative expression of Ccl2 by SPMs and LPMs from WT and Mif–/– mice 22 hours after CLP induction (n = 4 mice per group, 2-way ANOVA with Sidak’s multiple-comparison test). (C and D) Myeloid-derived MIF mediates i.p. SPM accumulation. Absolute cell count analyses of SPMs (C) and LPMs (D) in the peritoneal lavage of LysM-Cre+/+ Miffl/fl, LysM-Cre+/+, or Miffl/fl mice after sham or CLP surgery. LysM-Cre+/– Miffl/fl (visualized in the figure as half-filled circles) demonstrated similar SPM and LPM cell numbers as homozygous LysM-Cre+/+ Miffl/fl mice and were combined as 1 group. Flow cytometric analyses were performed on peritoneal cells collected 22 hours after CLP or sham surgery and included CountBright absolute counting beads in n = 3 animals/genotype. One-way ANOVA with Tukey’s multiple-comparison test. (E) Impact of Cxcr2 or Cd74 deficiency on SPM migration into LPS-conditioned peritonea. SPMs were isolated from WT, Cxcr2–/–, or Cd74–/– mice (after LPS injection, 12.5 mg/kg); labeled with CellTracker Orange and 1 × 106 cells transferred (i.v.) into WT mice; and followed 2 hours later by LPS challenge (12.5 mg/kg, i.p.). Labeled CellTracker Orange+ SPMs were measured in the peritoneal lavage by flow cytometry 18 hours later (Mif–/– recipients also shown as controls). Data are from n = 4 to 8 animals per group and representative of 2 replicate experiments, 1-way ANOVA with Tukey’s multiple-comparison test. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.