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 Article has an altmetric score of 4

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 6

LPMs express higher levels of MIF and CCL2 than SPMs.

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LPMs express higher levels of MIF and CCL2 than SPMs. (A–C) Confirmation...
(A–C) Confirmation of MIF-dependent regulation of Tnfa, Il1a, and Il1b expression by SPMs in contrast to LPMs. Quantitative expression by qPCR of (A) Tnfa, (B) Il1a, and (C) Il1b in SPMs and LPMs isolated from WT and Mif–/– animals 22 hours after CLP. n = 4 animals per group with replication (2-way ANOVA with Sidak’s multiple-comparison test). (D–G) We confirmed cellular protein expression in SPMs and LPMs by flow cytometry. Intracellular cytokine expression assessed by flow cytometry in post-CLP SPMs and LPMs showing (D) cytokine-expressing macrophages as percentage of total SPMs/LPMs and (E) MFI as percentage of fluorescence-minus-one (FMO) control. (F and G) Flow cytometry analysis of the MIF receptors CD74, CXCR2, and CXCR4 expressed by SPMs and LPMs after CLP, (F) expressed as percentage of total SPMs/LPMs, and as (G) MFI percentage of FMO control. Results are from 3 independent experiments, n = 6 animals per group, 2-way ANOVA with Sidak’s multiple-comparison test. (H and I) In vitro confirmation of induced production of MIF and CCL2 by LPMs versus SPMs. (H) MIF and (I) CCL2 production from WT SPMs and LPMs stimulated with LPS (100 ng/mL, 1 × 105 cells/well). Cytokine concentrations in supernatants were measured by ELISA. The results are from 3 independent experiments, and data are expressed as mean ± SEM, n = 5 to 11 samples per time point. Significance determined by 1-way ANOVA with Tukey’s multiple-comparison test (H) or Kruskal-Wallis test with Dunn’s multiple-comparison test (I). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.