Inhibition of Fgr Prevents Pulmonary Fibrosis

肺纤维化可自发发生，如特发性肺纤维化（IPF），或在电离辐射后发生。 辐射、二氧化硅暴露或COVID-19感染。衰老与辐射引起的 肺纤维化（RIPF）和IPF。衰老先于小鼠RIPF的纤维化，并在COVID-19中报道 患者通过衰老清除药物清除衰老细胞（SC）是一种有吸引力的抗纤维化策略。 然而，senolytics可能是非特异性的，可以去除潜在的有益和有害的SC。之甚少 衰老细胞如何诱发肺纤维化SC退出细胞周期，诱导p16，增加 衰老相关β-半乳糖苷酶（SA-β-gal），并分泌衰老相关的分泌型 表型（SASP）蛋白。SASP包括可能引发和加重纤维化的促炎细胞因子。 因此，利用辐射作为诱导衰老的模型系统，我们建议建立并验证一个 通过靶向一种衰老蛋白而不去除SC来特异性减轻肺纤维化。通过RNA-seq 纯的SC和通过照射肺的单细胞RNA-seq（scRNAseq），我们发现酪氨酸激酶Fgr是 在衰老细胞中高度诱导。Fgr阳性小鼠肺细胞在体外诱导纤维化的生物标志物， 抑制剂TL 02 -59处理消除了促纤维化基因的诱导。我们的初步数据显示：1）在 小鼠肺衰老细胞，Fgr抑制剂TL 02 -59消除靶细胞中促纤维化基因的诱导，2） 在Fgr基因敲除小鼠的肺细胞中，辐射引起衰老，但不能诱导肺细胞中的促纤维化基因。 靶细胞，3）来自RIPF、硅肺和IPF的人肺显示Fgr和衰老标志物的诱导 p16，4）TL 02 -59减少促纤维化SASP趋化因子的分泌以吸引免疫细胞， 通过TL 02 -59或通过衰老抑制剂MMS 350的体内Fgr降低纤维化基因的表达。我们 假设衰老细胞中Fgr通过分泌促炎SASP蛋白引发肺纤维化 以及通过向肺部募集炎症免疫细胞。我们进一步假设，Fgr的抑制，小 分子TL 02 -59或通过衰老抑制剂MMS 350间接地将防止肺纤维化。我们将使用 来自C57 BL/6对照和Fgr敲除（Fgr-/-）小鼠的小鼠原代肺细胞，以证实Fgr在体内的作用 在C57 BL/6和C57 BL/6 Fgr-/-小鼠中。最后，我们将确定特异性抑制Fgr可防止肺 纤维化具体目标1将确定肺细胞衰老诱导Fgr并启动肺纤维化 通过分泌的促炎SASP和骨髓向肺的募集作用， 衍生的炎性细胞。具体目标2将使用Fgr -/-确定肺纤维化需要Fgr 小鼠具体目标3将确立Fgr的特异性和靶向药理学抑制阻断肺纤维化。 我们的创新方法将确定衰老肺细胞中Fgr的诱导 通过分泌促炎SASP蛋白和趋化性募集 炎症细胞我们提出的研究将导致开发一种新的肺纤维化缓解剂。

Pulmonary fibrosis can arise spontaneously as in idiopathic pulmonary fibrosis (IPF), or following ionizing irradiation, silica exposure, or COVID-19 infection. Senescence has been implicated in both radiation-induced pulmonary fibrosis (RIPF) and IPF. Senescence precedes fibrosis in mouse RIPF and reported in COVID-19 patients. Clearance of senescent cells (SCs) by senolytic drugs present an attractive anti-fibrosis strategy. However, senolytics may be non-specific and remove potentially beneficial as well as harmful SCs. Little is known about how senescent cells induce pulmonary fibrosis. SCs exit cell cycle, induce p16, increase senescence associated beta-galactosidase (SA-𝝱-gal), and secrete senescence associated secretory phenotype (SASP) proteins. SASP include proinflammatory cytokines that may initiate and exacerbate fibrosis. Therefore, using radiation as a model system to induce senescence, we propose to establish and validate a specific mitigator of lung fibrosis by targeting one senescent protein while not removing the SCs. By RNA-seq of pure SCs and by single cell RNA-seq (scRNAseq) of irradiated lungs, we discovered that tyrosine kinase Fgr is highly induced in senescent cells. Fgr positive mouse lung cells induce biomarkers of fibrosis in vitro, and Fgr inhibitor, TL02-59 treatment, abrogates the induction of profibrotic genes. Our preliminary data show: 1) in mouse lung senescent cells, Fgr inhibitor TL02-59 abrogates the induction of profibrotic genes in target cells, 2) in lung cells from Fgr knockout mouse, senescence occurs with radiation, but fail to induce profibrotic genes in target cells, 3) human lungs from RIPF, silicosis, and IPF show induction of Fgr and senescent marker p16, 4) TL02-59 reduces secretion of profibrotic SASP chemokines for attracting immunocytes, 5) inhibition of Fgr in vivo, either by TL02-59, or by senescence inhibitor MMS350, reduces expression of fibrotic genes. We hypothesize, Fgr in senescent cells initiates pulmonary fibrosis by secretion of proinflammatory SASP proteins and by recruiting inflammatory immunocytes to the lungs. We further hypothesize that inhibition of Fgr by small molecule TL02-59 or indirectly by the senescence inhibitor, MMS350, will prevent lung fibrosis. We will use mouse primary lung cells from C57BL/6 control and Fgr knockout (Fgr-/-) mice to confirm the role of Fgr in vivo in C57BL/6 and C57BL/6 Fgr-/- mice. Finally, we will establish that specific inhibition of Fgr prevents lung fibrosis. Specific Aim 1 will establish that lung cell senescence induces Fgr and initiates pulmonary fibrosis by the actions of secreted proinflammatory SASP and recruitment to the lungs of bone marrow derived inflammatory cells. Specific Aim 2 will establish that Fgr is required for pulmonary fibrosis using Fgr -/- mice. Specific Aim 3 will establish that specific and targeted pharmacologic inhibition of Fgr blocks lung fibrosis. Our innovative approach will establish that Fgr induction in senescent lung cells causes pulmonary fibrosis through secretion of proinflammatory SASP proteins and chemotactic recruitment of inflammatory cells. Our proposed studies will lead to the development of a new mitigator of pulmonary fibrosis.