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Additional file 2: Supplementary Figure 1. Flow cytometry gating strategy. A representative spinal cord sample is shown.

Additional file 1: Supplementary Table 1. Antibodies for flow cytometry.

Spinal cord injury (SCI) induces a glial response in which astrocytes become activated and produce inflammatory mediators. The molecular basis for regulation of glial-innate immune responses remains poorly understood. Here, we examined the activation of retinoic acid inducible gene (RIG)-like receptors (RLRs) and their involvement in regulating inflammation following SCI. We show that astrocytes express two intracellular RLRs: RIG-I and melanoma differentiation-associated gene 5 (MDA5). SCI and stretch injury of cultured astrocytes stimulated RLR signaling as determined by phosphorylation of IRF3 leading to production of type I interferons (IFNs). RLR signaling stimulation with synthetic RNA resulted in RLR activation, phosphorylation of interferon regulatory factor 3 (IRF3), and increased expression of glial fibrillary acidic protein and vimentin, two hallmarks of reactive astrocytes. Moreover, mitochondrial E3 ubiquitin protein ligase 1 (MUL1), an RLR inhibitor, decreased production of glial fibrillary acidic protein (GFAP) and vimentin following RIG-I signaling stimulation. Our findings identify a role for RLR signaling and type I IFN in regulating astrocyte innate immune responses after SCI.