TGFB1 and retinal ischemia: For instance, after retinal ischemia/reperfusion injury, IL-4 promotes microglial polarization toward a neuroprotective phenotype [49], whereas the disruption of transforming growth factor-β (TGF-β) signaling in microglia exacerbates retinal neovascularization in OIR by promoting leukocytosis and Igf1 expression [50].