Cathelicidin antimicrobial peptide expression in neutrophils and neurons antagonistically modulates neuroinflammation
Subash Chand Verma, … , Roland Liblau, Julien Diana
Subash Chand Verma, … , Roland Liblau, Julien Diana
Published December 10, 2024
Citation Information: J Clin Invest. 2025;135(3):e184502. https://doi.org/10.1172/JCI184502.
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Research Article Autoimmunity Immunology

Cathelicidin antimicrobial peptide expression in neutrophils and neurons antagonistically modulates neuroinflammation

Abstract

Multiple sclerosis (MS) is an autoimmune disease that affects the CNS, the pathophysiology of which remains unclear and for which there is no definitive cure. Antimicrobial peptides (AMPs) are immunomodulatory molecules expressed in various tissues, including the CNS. Here, we investigated whether the cathelicidin-related AMP (CRAMP) modulated the development of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. We showed that, at an early stage, CNS-recruited neutrophils produced neutrophil extracellular traps (NETs) rich in CRAMP that were required for EAE initiation. NET-associated CRAMP stimulated IL-6 production by dendritic cells via the cGAS/STING pathway, thereby promoting encephalitogenic Th17 response. However, at a later disease stage, neurons also expressed CRAMP that reduced EAE severity. Camp knockdown in neurons led to disease exacerbation, while local injection of CRAMP1–39 at the peak of EAE promoted disease remission. In vitro, CRAMP1–39 regulated the activation of microglia and astrocytes through the formyl peptide receptor (FPR) 2. Finally, administration of butyrate, a gut microbiota-derived metabolite, stimulated the expression of neural CRAMP via the free fatty acids receptors 2/3 (FFAR2/3), and prevented EAE. This study shows that CRAMP produced by different cell types has opposing effects on neuroinflammation, offering therapeutic opportunities for MS and other neuroinflammatory disorders.

Authors

Subash Chand Verma, Emmanuelle Enée, Kanchanadevi Manasse, Feriel Rebhi, Axelle Penc, David Romeo-Guitart, Cuc Bui Thi, Matthias Titeux, Franck Oury, Simon Fillatreau, Roland Liblau, Julien Diana

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Figure 1

Opposite role of CRAMP during EAE.

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Opposite role of CRAMP during EAE. (A) mRNA expression of CRAMP was anal...
(A) mRNA expression of CRAMP was analyzed by RT-qPCR in SC from C57BL/6 WT mice at different days after EAE induction. Data are the median plus or minus interquartile range of 5 to 11 independent mice per group from 4 independent experiments. (B) Camp–/– C57BL/6 mice and WT littermate controls (n = 30 mice per group from 6 independent experiments) were immunized with MOG35-55 to induce EAE. Clinical scores are shown (data are represented as mean ± SEM). (C and D) Cells from draining lymph nodes (C) or SC (D) were recovered on day 7 or 12, respectively, after EAE induction in Camp–/– and WT C57BL/6 mice and stained with I-Ab MOG35-55 tetramer. Data are the frequency and number of tetramer+ cells among CD45+βTCR+CD4+ cells. Median plus or minus interquartile range of 6 independent mice per group from 3 independent experiments is shown. (E) Frequency of IFN-γ+ and IL-17+ cells in CD4+ T cells recovered farom the SC at day 12 after EAE induction in Camp–/– and WT C57BL/6 mice and restimulated for 6 hours with PMA/ionomycin. Median plus or minus interquartile range of 6 independent mice per group is shown from 3 independent experiments. (F−H) WT mice (n = 15 mice per group from 3 independent experiments) were immunized with MOG35-55 to induce EAE. Mice were treated with CRAMP or scCRAMP i.p. at day 7 (F) or at day 15 (G) or i.t. at day 9 (H) after EAE induction. Clinical scores are shown (data are represented as mean ± SEM). (I) NF-L protein levels were measured in the serum 15 days after EAE induction in WT mice treated as in G and in unmanipulated (naive) WT mice. Data are the median plus or minus interquartile range of 7 independent mice per group from 3 independent experiments. (J and K) Expression of CD44 on astrocytes (J) and CD86 on microglia (K) was determined by flow cytometry at day 15 after EAE induction in the SC of WT mice treated as in G and in unmanipulated (naive) WT mice. Data are the median plus or minus interquartile range of 6 independent mice per group from 3 independent experiments. Comparison between each group was performed using the nonparametric Mann-Whitney U test or Kruskal-Wallis test followed up by Dunn’s post test when more than 2 groups were compared. For evaluating differences between EAE scores over time, a 2-way ANOVA with Tukey’s multiple-comparisons test was used.