Lysophosphatidic acid stimulates epidermal growth factor-family ectodomain shedding and paracrine signaling from human lung fibroblasts.
Lysophosphatidic acid stimulates epidermal growth factor-family ectodomain shedding and paracrine signaling from human lung fibroblasts.
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DOI：
10.1111/j.1524-475x.2010.00655.x
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发表时间：
2011-03
期刊：
影响因子：
--
通讯作者：
Tschumperlin DJ
中科院分区：
文献类型：
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作者：
Shiomi T;Boudreault F;Padem N;Higashiyama S;Drazen JM;Tschumperlin DJ
溶血磷脂酸（LPA）是一种生物活性脂质介质，参与组织修复和伤口愈合。它在成纤维细胞中介导多种功能效应，包括增殖、迁移和收缩，但对其向参与伤口愈合的其他细胞类型诱发旁分泌信号传导的能力知之甚少。我们假设LPA刺激的人肺成纤维细胞会表现出EGFR配体的胞外域脱落，这些配体向肺上皮细胞发出信号。为了验证这一假设，我们使用碱性磷酸酶（AP）标记的表皮生长因子受体（EGFR）配体质粒转染到CCL-151肺成纤维细胞，ELISA检测脱落的天然配体。LPA诱导转染的AP标记的HB-EGF、双调蛋白和TGF-α的脱落;未转染的成纤维细胞在基线条件下脱落双调蛋白和HB-EGF，并且响应于LPA增加HB-EGF的脱落。用LPA（10 μM）处理成纤维细胞导致ERK 1/2磷酸化水平升高（5分钟时诱导增加3.3 ± 0.04倍），c-fos（30分钟时增加59 ± 7.9倍）、HB-EGF（4小时时增加28 ± 4.7倍）和双调蛋白（4小时时增加5.7 ± 1.8倍）的mRNA表达增强，96小时时增殖增强。然而，这些成纤维细胞对LPA的反应都不需要胞外域脱落或EGFR活性。为了测试LPA刺激来自成纤维细胞的旁分泌信号传导的能力，我们从LPA刺激的CCL-151细胞中转移条件培养基，并且发现报告基因A549细胞中增强的EGFR和ERK 1/2磷酸化超过了单独转移的LPA所能解释的。约三分之一（37%，P < 0.05）的缓解归因于EGFR活化。这些数据表明，LPA介导EGF家族胞外域脱落，导致从肺成纤维细胞到上皮细胞的旁分泌信号增强。
Lysophospatidic acid (LPA) is a bioactive lipid mediator implicated in tissue repair and wound healing. It mediates diverse functional effects in fibroblasts, including proliferation, migration and contraction, but less is known about its ability to evoke paracrine signaling to other cell types involved in wound healing. We hypothesized that human pulmonary fibroblasts stimulated by LPA would exhibit ectodomain shedding of EGFR ligands that signal to lung epithelial cells. To test this hypothesis, we used alkaline phosphatase (AP) -tagged EGF receptor (EGFR) ligand plasmids transfected into CCL-151 lung fibroblasts, and ELISAs to detect shedding of native ligands. LPA induced shedding of transfected AP-tagged HB-EGF, amphiregulin and TGF-alpha;non-transfected fibroblasts shed amphiregulin and HB-EGF under baseline conditions, and increased shedding of HB-EGF in response to LPA.. Treatment of fibroblasts with LPA (10 μM) resulted in elevated phosphorylation of ERK1/2 (3.3 ± 0.04 fold induction at 5 minutes), enhanced expression of mRNA for c-fos (59 ± 7.9-fold at 30 minutes), HB-EGF (28 ± 4.7-fold at 4 hours) and amphiregulin (5.7 ± 1.8-fold at 4 hours), and enhanced proliferation at 96 hours. However, none of these fibroblast responses to LPA required ectodomain shedding or EGFR activity. To test the ability of LPA to stimulate paracrine signaling from fibroblasts, we transferred conditioned medium from LPA stimulated- CCL-151 cells, and found enhanced EGFR and ERK1/2 phosphorylation in reporter A549 cells in excess of what could be accounted for by transferred LPA alone. About one-third of th response (37%, P < 0.05) was attributable to EGFR activation. These data demonstrate that LPA mediates EGF-family ectodomain shedding, resulting in enhanced paracrine signaling from lung fibroblasts to epithelial cells.