Pedroza Mesias, Le Thuy T, Lewis Katherine, Karmouty-Quintana Harry, To Sarah, George Anuh T, Blackburn Michael R, Tweardy David J, Agarwal Sandeep K
*Department of Medicine and Department of Infectious Disease, Baylor College of Medicine, Houston, Texas, USA; and Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston Medical School, Houston, Texas, USA.
*Department of Medicine and Department of Infectious Disease, Baylor College of Medicine, Houston, Texas, USA; and Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston Medical School, Houston, Texas, USA
FASEB J. 2016 Jan;30(1):129-40. doi: 10.1096/fj.15-273953. Epub 2015 Aug 31.
Lung fibrosis is the hallmark of the interstitial lung diseases. Alveolar epithelial cell (AEC) injury is a key step that contributes to a profibrotic microenvironment. Fibroblasts and myofibroblasts subsequently accumulate and deposit excessive extracellular matrix. In addition to TGF-β, the IL-6 family of cytokines, which signal through STAT-3, may also contribute to lung fibrosis. In the current manuscript, the extent to which STAT-3 inhibition decreases lung fibrosis is investigated. Phosphorylated STAT-3 was elevated in lung biopsies from patients with idiopathic pulmonary fibrosis and bleomycin (BLM)-induced fibrotic murine lungs. C-188-9, a small molecule STAT-3 inhibitor, decreased pulmonary fibrosis in the intraperitoneal BLM model as assessed by arterial oxygen saturation (control, 84.4 ± 1.3%; C-188-9, 94.4 ± 0.8%), histology (Ashcroft score: untreated, 5.4 ± 0.25; C-188-9, 3.3 ± 0.14), and attenuated fibrotic markers such as diminished α-smooth muscle actin, reduced collagen deposition. In addition, C-188-9 decreased the expression of epithelial injury markers, including hypoxia-inducible factor-1α (HIF-1α) and plasminogen activator inhibitor-1 (PAI-1). In vitro studies show that inhibition of STAT-3 decreased IL-6- and TGF-β-induced expression of multiple genes, including HIF-1α and PAI-1, in AECs. Furthermore, C-188-9 decreased fibroblast-to-myofibroblast differentiation. Finally, TGF-β stimulation of lung fibroblasts resulted in SMAD2/SMAD3-dependent phosphorylation of STAT-3. These findings demonstrate that STAT-3 contributes to the development of lung fibrosis and suggest that STAT-3 may be a therapeutic target in pulmonary fibrosis.
肺纤维化是间质性肺疾病的标志。肺泡上皮细胞（AEC）损伤是促成促纤维化微环境的关键步骤。成纤维细胞和平滑肌成纤维细胞随后积聚并沉积过多的细胞外基质。除了转化生长因子-β（TGF-β）外，通过信号转导和转录激活因子3（STAT-3）发挥作用的白细胞介素-6（IL-6）细胞因子家族也可能促成肺纤维化。在本手稿中，研究了STAT-3抑制降低肺纤维化的程度。在特发性肺纤维化患者和博来霉素（BLM）诱导的纤维化小鼠肺组织活检中，磷酸化STAT-3水平升高。小分子STAT-3抑制剂C-188-9在腹腔注射BLM模型中可降低肺纤维化，通过动脉血氧饱和度评估（对照组，84.4±1.3%；C-188-9组，94.4±0.8%）、组织学检查（阿什克罗夫特评分：未治疗组，5.4±0.25；C-188-9组，3.3±0.14）以及减轻纤维化标志物，如减少α平滑肌肌动蛋白、降低胶原蛋白沉积。此外，C-188-9降低了上皮损伤标志物的表达，包括缺氧诱导因子-1α（HIF-1α）和纤溶酶原激活物抑制剂-1（PAI-1）。体外研究表明，抑制STAT-3可降低AEC中IL-6和TGF-β诱导的多个基因的表达，包括HIF-1α和PAI-1。此外，C-188-9减少了成纤维细胞向平滑肌成纤维细胞的分化。最后，TGF-β刺激肺成纤维细胞导致STAT-3的SMAD2/SMAD3依赖性磷酸化。这些发现表明STAT-3促成了肺纤维化的发展，并提示STAT-3可能是肺纤维化的治疗靶点。
