Graft-versus-host disease of the CNS is mediated by TNF upregulation in microglia
Nimitha R. Mathew, … , Marco Prinz, Robert Zeiser
Nimitha R. Mathew, … , Marco Prinz, Robert Zeiser
Published December 17, 2019
Citation Information: J Clin Invest. 2020;130(3):1315-1329. https://doi.org/10.1172/JCI130272.
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Research Article

Graft-versus-host disease of the CNS is mediated by TNF upregulation in microglia

Abstract

Acute graft-versus-host disease (GVHD) can affect the central nervous system (CNS). The role of microglia in CNS-GVHD remains undefined. In agreement with microglia activation, we found that profound morphological changes and MHC-II and CD80 upregulation occurred upon GVHD induction. RNA sequencing–based analysis of purified microglia obtained from mice with CNS-GVHD revealed TNF upregulation. Selective TNF gene deletion in microglia of Cx3cr1creER Tnffl/– mice reduced MHC-II expression and decreased CNS T cell infiltrates and VCAM-1+ endothelial cells. GVHD increased microglia TGF-β–activated kinase-1 (TAK1) activation and NF-κB/p38 MAPK signaling. Selective Tak1 deletion in microglia using Cx3cr1creER Tak1fl/fl mice resulted in reduced TNF production and microglial MHC-II and improved neurocognitive activity. Pharmacological TAK1 inhibition reduced TNF production and MHC-II expression by microglia, Th1 and Th17 T cell infiltrates, and VCAM-1+ endothelial cells and improved neurocognitive activity, without blocking graft-versus-leukemia effects. Consistent with these findings in mice, we observed increased activation and TNF production of microglia in the CNS of GVHD patients. In summary, we prove a role for microglia in CNS-GVHD, identify the TAK1/TNF/MHC-II axis as a mediator of CNS-GVHD, and provide a TAK1 inhibitor–based approach against GVHD-induced neurotoxicity.

Authors

Nimitha R. Mathew, Janaki M. Vinnakota, Petya Apostolova, Daniel Erny, Shaimaa Hamarsheh, Geoffroy Andrieux, Jung-Seok Kim, Kathrin Hanke, Tobias Goldmann, Louise Chappell-Maor, Nadia El-Khawanky, Gabriele Ihorst, Dominik Schmidt, Justus Duyster, Jürgen Finke, Thomas Blank, Melanie Boerries, Bruce R. Blazar, Steffen Jung, Marco Prinz, Robert Zeiser

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Figure 4

Downstream targets of TAK1 signaling are elevated in microglia during GVHD.

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Downstream targets of TAK1 signaling are elevated in microglia during GV...
(A) Heatmap based on RNA-Seq showing the top hits of PI3K/Akt/mTOR signaling pathway from the microglia of untreated BALB/c mice (n = 4) or BALB/c mice on day 14 after allo-HCT (n = 4) or syn-HCT (n = 4). Color code represents the Z score log2 intensity. (B) A representative flow cytometry plot showing intracellular phospho–p38 MAPK in microglia (CD45loCD11b+) from brains of untreated BALB/c mice or BALB/c mice on day 7 after syn-HCT or allo-HCT. (C) The scatter plot shows the quantification (fold change of MFI) of intracellular phospho–p38 MAPK expression in microglia from brains of untreated BALB/c mice (n = 14) or BALB/c mice on day 7 after syn-HCT (n = 15) or allo-HCT (n = 15) as indicated. The experiment was repeated 3 times, and the results (mean ± SEM) were pooled. The P values were calculated using 1-way ANOVA. (D–J) Western blot using protein derived from primary murine microglia treated with different concentrations of murine TNF for 24 hours as indicated. (D, F, and H) Representative Western blot images showing the expression of phospho-TAK1 and total TAK1 (D), phospho-JNK and total JNK (F), and phospho–NF-κB p65, total NF-κB p65, and IκB (H) with β-actin as loading control. (E, G, I, and J) Quantification of phospho-TAK1/total TAK1 (E), phospho-JNK/total JNK (G), phospho–NF-κB p65/total NF-κB p65 (I), and IκB (J) normalized to β-actin (fold change with respect to controls treated with vehicle [0 μM TNF]) in microglia treated as described. The experiment was repeated 4 times, and the results (mean ± SEM) were pooled with n = 4 biologically independent samples per group. Each data point represents an individual sample of 1 independent cell culture experiment. P values were calculated using 1-way ANOVA.