TNFR2 limits proinflammatory astrocyte functions during EAE induced by pathogenic DR2b-restricted T cells
Itay Raphael, Francisco Gomez-Rivera, Rebecca A. Raphael, Rachel R. Robinson, Saisha Nalawade, Thomas G. Forsthuber
Itay Raphael, Francisco Gomez-Rivera, Rebecca A. Raphael, Rachel R. Robinson, Saisha Nalawade, Thomas G. Forsthuber
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Research Article Immunology

TNFR2 limits proinflammatory astrocyte functions during EAE induced by pathogenic DR2b-restricted T cells

Abstract

Multiple sclerosis (MS) is an autoimmune neuroinflammatory disease where the underlying mechanisms driving disease progression have remained unresolved. HLA-DR2b (DRB1*15:01) is the most common genetic risk factor for MS. Additionally, TNF and its receptors TNFR1 and TNFR2 play key roles in MS and its preclinical animal model, experimental autoimmune encephalomyelitis (EAE). TNFR2 is believed to ameliorate CNS pathology by promoting remyelination and Treg function. Here, we show that transgenic mice expressing the human MHC class II (MHC-II) allele HLA-DR2b and lacking mouse MHC-II and TNFR2 molecules, herein called DR2bΔR2, developed progressive EAE, while disease was not progressive in DR2b littermates. Mechanistically, expression of the HLA-DR2b favored Th17 cell development, whereas T cell–independent TNFR2 expression was critical for restraining of an astrogliosis-induced proinflammatory milieu and Th17 cell responses, while promoting remyelination. Our data suggest the TNFR2 signaling pathway as a potentially novel mechanism for curtailing astrogliosis and promoting remyelination, thus providing new insights into mechanisms limiting progressive MS.

Authors

Itay Raphael, Francisco Gomez-Rivera, Rebecca A. Raphael, Rachel R. Robinson, Saisha Nalawade, Thomas G. Forsthuber

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Figure 6

CNS TNFR2 limits chronic astrogliosis and astrocyte activation.

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CNS TNFR2 limits chronic astrogliosis and astrocyte activation. Passive ...
Passive EAE induced via adoptive transfer of MOG35–55–reactive T cells from DR2b donors into DR2b and DR2bΔR2 recipients. (A) Representative IF staining of cerebellum sections analyzed at the progression phase of disease, showing myelin stain (FluoroMyelin, red) and astrocytes (GFAP, green). Scale bar: 50 μm. (B) Representative IF staining of cerebellum sections analyzed at onset (top), acute phase (middle), and progression phase (bottom) of disease, showing myelin stain (FluoroMyelin, red), astrocytes (GFAP, green), and nuclear stain (DAPI, blue). Scale bar: 200 μm. Representative data from 4 independent experiments with 3–6 mice per group (A and B). (C) Percentage of GFAP-stained area per cerebellum as in B, analyzed at the progression phase of disease. Representative data of 3 independent mice per group. (D) Number of astrocytes during EAE progression phase. Data from 2 independent experiments, n = 8 per group. (E) Concentration of CXCL13 in whole CNS tissue homogenate at acute disease. Pooled data of 3 independent experiments, n = 10 mice per group. (F) mRNA expression level of Cxcl13 in whole CNS tissue homogenate at acute disease. Representative data of 3 independent experiments, n = 3–5 mice per group. (G) Astrocytes were isolated at acute phase and disease progression phase and analyzed for mRNA expression as indicated. Shown are fold changes relative to the experimental mean expression per each gene. Representative data of 2 experiments (Cxcr5 and Mki67) or 3 experiments (Il6, Csf2, Ssp1, Ccl11) with n = 5–8 mice per group. (H) Concentration of IL-6, GM-CSF, and osteopontin (OPN) in whole CNS tissue homogenate at acute disease. Data pooled from 3 independent experiments, n = 6–10 mice per group. Statistical significance was determined by Student’s 2-tailed t test with Welch’s correction and multiple comparisons with Holm-Šídák correction (E). *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001. Error bars indicate mean ± SD.