ABSTRACT: Microglia-mediated neuroinflammation plays a dual role in various brain diseases due to distinct microglial phenotypes, including deleterious M1 and neuroprotective M2. There is growing evidence that the peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone prevents lipopolysaccharide (LPS)-induced microglial activation. Here, we observed that antagonizing PPARγ promoted LPS-stimulated changes in polarization from the M1 to the M2 phenotype in primary microglia. PPARγ antagonist T0070907 increased the expression of M2 markers, including CD206, IL-4, IGF-1, TGF-β1, TGF-β2, TGF-β3, G-CSF, and GM-CSF, and reduced the expression of M1 markers, such as CD86, Cox-2, iNOS, IL-1β, IL-6, TNF-α, IFN-γ, and CCL2, thereby inhibiting NFκB-IKKβ activation. Moreover, antagonizing PPA