Taken together, these novel results strongly support that restoring a balanced pool of host-derived kynurenine-based and microbiota-derived indole-based ligands of AHR via post-stroke administration of indole-based ligands of AHR can improve stroke outcomes in mice through the regulation of MG-mediated neuroinflammation and surface molecules directly involved in antigen presentation and immune co-stimulation. The gene discussed is AHR; the disease is Stroke.