Unit of Biophysics and Bioengineering, Department of Biomedicine, School of Medicine, Universitat de Barcelona, 08036 Barcelona, Spain.
Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain.
Int J Mol Sci. 2017 Nov 16;18(11):2431. doi: 10.3390/ijms18112431.
Idiopathic pulmonary fibrosis (IPF) is an aggressive disease in which normal lung parenchyma is replaced by a stiff dysfunctional scar rich in activated fibroblasts and collagen-I. We examined how the mechanochemical pro-fibrotic microenvironment provided by matrix stiffening and TGF-β1 cooperates in the transcriptional control of collagen homeostasis in normal and fibrotic conditions. For this purpose we cultured fibroblasts from IPF patients or control donors on hydrogels with tunable elasticity, including 3D collagen-I gels and 2D polyacrylamide (PAA) gels. We found that TGF-β1 consistently increased while decreasing mRNA levels in hydrogels exhibiting pre-fibrotic or fibrotic-like rigidities concomitantly with an enhanced activation of the FAK/Akt pathway, whereas FAK depletion was sufficient to abrogate these effects. We also demonstrate a synergy between matrix stiffening and TGF-β1 that was positive for and negative for . Remarkably, the expression upregulation elicited by TGF-β1 alone or synergistically with matrix stiffening were higher in IPF-fibroblasts compared to control fibroblasts in association with larger FAK and Akt activities in the former cells. These findings provide new insights on how matrix stiffening and TGF-β1 cooperate to elicit excessive collagen-I deposition in IPF, and support a major role of the FAK/Akt pathway in this cooperation.
特发性肺纤维化 (IPF) 是一种侵袭性疾病，正常的肺实质被僵硬的功能失调的疤痕所取代，这些疤痕富含激活的成纤维细胞和胶原-I。我们研究了基质变硬和 TGF-β1 提供的机械化学促纤维化微环境如何在正常和纤维化条件下协同控制胶原稳态的转录控制。为此，我们在具有可调节弹性的水凝胶上培养来自 IPF 患者或对照供体的成纤维细胞，包括 3D 胶原-I 凝胶和 2D 聚丙烯酰胺 (PAA) 凝胶。我们发现 TGF-β1 一致增加 ，而降低 在表现出前纤维化或纤维化样刚性的水凝胶中的 mRNA 水平，同时伴随着 FAK/Akt 途径的激活增强，而 FAK 耗竭足以消除这些影响。我们还证明了基质变硬和 TGF-β1 之间的协同作用，对 呈正相关，对 呈负相关。值得注意的是，与对照成纤维细胞相比，TGF-β1 单独或与基质变硬协同上调的 表达在 IPF 成纤维细胞中更高，与前者细胞中更大的 FAK 和 Akt 活性相关。这些发现提供了新的见解，即基质变硬和 TGF-β1 如何协同作用导致 IPF 中胶原-I 的过度沉积，并支持 FAK/Akt 途径在这种协同作用中的主要作用。
