Transforming Growth Factor-β1 (TGF-β1)-stimulated Fibroblast to Myofibroblast Differentiation Is Mediated by Hyaluronan (HA)-facilitated Epidermal Growth Factor Receptor (EGFR) and CD44 Co-localization in Lipid Rafts
Transforming Growth Factor-β1 (TGF-β1)-stimulated Fibroblast to Myofibroblast Differentiation Is Mediated by Hyaluronan (HA)-facilitated Epidermal Growth Factor Receptor (EGFR) and CD44 Co-localization in Lipid Rafts
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DOI：
10.1074/jbc.m113.451336
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发表时间：
2013-05-24
影响因子：
4.8
通讯作者：
Steadman, Robert
中科院分区：
文献类型：
--
作者：
Midgley, Adam C.;Rogers, Mathew;Steadman, Robert
成纤维细胞向肌成纤维细胞的分化促进了伤口的有效愈合，并在很大程度上受细胞因子转化生长因子-β1(TGF-β1)的调节。肌成纤维细胞表达α-平滑肌肌动蛋白，存在于肉芽组织中，在肉芽组织中负责伤口收缩。我们以前的研究表明，成纤维细胞对转化生长因子-β1的反应依赖于并由线性多糖透明质酸(HA)介导。HA受体CD44和表皮生长因子受体(EGFR)都参与了这种分化反应。本研究的目的是了解HA、CD44和EGFR调节的转化生长因子-β1依赖分化的机制。CD44和EGFR在膜结合的脂筏中的共同定位是分化所必需的，这触发了下游丝裂原活化蛋白激酶(MAPK/ERK)和钙/钙调蛋白激酶II(CaMKII)的激活。我们还发现，ERK的磷酸化是CaMKII磷酸化的上游，ERK的激活是CaMKII信号转导所必需的，这两种酶对分化都是必不可少的。此外，HA合成酶-2(HAS2)siRNA减弱了ERK和CaMKII信号和CD44在脂筏中的滞留，阻止了分化。综上所述，这些数据表明，依赖HAS2的HA的产生通过促进CD44与膜结合的脂筏中的EGFR的相互作用来促进依赖于转化生长因子-β1的成纤维细胞的分化。这会诱导MAPK/ERK，然后激活CaMKII，导致分化。该通路与经典的依赖于转化生长因子-β1的SMAD信号通路协同作用，可能为创伤愈合的干预提供新的机会。
Fibroblast to myofibroblast differentiation drives effective wound healing and is largely regulated by the cytokine transforming growth factor-beta 1 (TGF-beta 1). Myofibroblasts express alpha-smooth muscle actin and are present in granulation tissue, where they are responsible for wound contraction. Our previous studies show that fibroblast differentiation in response to TGF-beta 1 is dependent on and mediated by the linear polysaccharide hyaluronan (HA). Both the HA receptor, CD44, and the epidermal growth factor receptor (EGFR) are involved in this differentiation response. The aim of this study was to understand the mechanisms linking HA-, CD44-, and EGFR-regulated TGF-beta 1-dependent differentiation. CD44 and EGFR co-localization within membrane-bound lipid rafts was necessary for differentiation, and this triggered downstream mitogen-activated protein kinase (MAPK/ERK) and Ca2+/calmodulin kinase II (CaMKII) activation. We also found that ERK phosphorylation was upstream of CaMKII phosphorylation, that ERK activation was necessary for CaMKII signaling, and that both kinases were essential for differentiation. In addition, HA synthase-2 (HAS2) siRNA attenuated both ERK and CaMKII signaling and sequestration of CD44 into lipid rafts, preventing differentiation. In summary, the data suggest that HAS2-dependent production of HA facilitates TGF-beta 1-dependent fibroblast differentiation through promoting CD44 interaction with EGFR held within membrane-bound lipid rafts. This induces MAPK/ERK, followed by CaMKII activation, leading to differentiation. This pathway is synergistic with the classical TGF-beta 1-dependent SMAD-signaling pathway and may provide a novel opportunity for intervention in wound healing.