{
  "abstract": "Introduction Background: Systemic sclerosis (SSc) is marked by ongoing activation of fibroblasts, their transformation into myofibroblasts, and excessive buildup of extracellular matrix (ECM), especially type I collagen (COL1A1). A key driver of this fibrotic process is transforming growth factor beta 1 (TGFB1), which signals through both Smad-dependent and Smad-independent pathways. The chromatin remodeler SMARCA4 (also known as Brg1) plays a crucial role in this process by enabling TGFB1-induced myofibroblast differentiation and supporting the expression of TGFB1–Smad2 target genes. This highlights SMARCA4’s essential function in promoting fibrosis.Objectives: To investigate whether treprostinil inhibits profibrotic activity in systemic sclerosis fibroblasts (SSc-FBs) and to identify the underlying signaling pathways involved.Material and Methods Dermal fibroblasts were isolated from the affected skin of six patients with systemic sclerosis (SSc) and from matched healthy controls. SSc fibroblasts (SSc-FBs) were treated with treprostinil, either alone or in combination with antagonists targeting EP2, IP, PPARG, or Brg1, for 24 to 96 hours. Gene and protein expression levels of COL1A1, ACTA2, PFKP, IP, EP2, PTGIS, PPARG, TGFB1, SMAD3, and Brg1 were quantified using qPCR and Western blots. Cell proliferation and migration were monitored using Incucyte live-cell imaging.Results Compared to NL-FBs, SSc-FBs exhibited elevated expression of COL1A1, alpha smooth muscle (SMA) EP2, PFKP, Brg1, TGFB1, and SMAD3, along with reduced levels of PPARG and IP. Treatment with treprostinil significantly downregulated COL1A1, and compared to normal fibroblasts (NL-FBs), SSc fibroblasts (SSc-FBs) exhibited elevated expression of COL1A1, SMA, EP2, PFKP, Brg1, TGFB1, and SMAD3, along with reduced levels of PPARG and IP. Treatment with treprostinil significantly downregulated COL1A1 and SMA and inhibited both cell proliferation and migration. These antifibrotic effects were reversed by the EP2 antagonist PF-04418948 and the PPARG antagonist GW9662, but not by the IP antagonist RO1138452. Treprostinil also upregulated PPARG and suppressed PFKP, Brg1, TGFB1, and SMAD3 expression. Notably, inhibition of Brg1 using PFI-3 independently reduced COL1A1 expression in SSc-FBs but did not affect NL-FBs SMA, inhibited both cell proliferation and migration. These antifibrotic effects were reversed by the EP2 antagonist PF-04418948 and the PPARG antagonist GW9662, but not by the IP antagonist RO1138452. Treprostinil also upregulated PPARG and suppressed PFKP, Brg1, TGFB1, and SMAD3 expression. Notably, inhibition of Brg1 using PFI-3 independently reduced COL1A1 expression in SSc-FBs but had no effect in NL-FBs.Conclusions SSc-FBs demonstrate impaired prostacyclin–IP antifibrotic signaling. Treprostinil exerts its antifibrotic effects primarily through EP2 activation and PPARG upregulation, leading to suppression of key fibrotic mediators.",
  "authors": [
    {
      "affiliations": [
        "Universtity of Toledo, Toledo, USA"
      ],
      "name": "Bashar Kahaleh"
    },
    {
      "affiliations": [
        "Universtity of Toledo, Toledo, USA"
      ],
      "name": "Yongqing Wang"
    }
  ],
  "title": "P.026 Treprostinil, a prostacyclin analog, mitigates profibrotic signaling in scleroderma fibroblasts via the EP2–PPARG–SMARCA4 pathway",
  "uid": "551b5c8e-7f7a-590f-9675-3aa5f0f44a11"
}