PPARG and scleroderma: Moreover, it is known that PPARγ expression and function are impaired in scleroderma by different factors (TGFβ, CTGF, IFNγ, Wnt proteins, IL-13, hypoxia) while fibrosis development is associated to a mutual inhibitory interaction between TGFβ and PPARγ that contributes to disease progression9, 10.