Physical Strain & Hypertrophic Scar--Integrin Signaling

严重烧伤患者高度紧张的组织中的毁容、功能障碍的增生性瘢痕(HS)给人留下了不可磨灭的印象。目前尚不清楚高组织张力如何促进HS，但很明显，环境压力通过整合素连接的细胞-细胞和细胞外基质(ECM)相互作用调节成纤维细胞的基因表达、成纤维细胞的排列和细胞外基质(ECM)的形态。整合素的构象变化介导粘着斑激酶(FAK)的激活和随后酪氨酸残基的磷酸化。因此，FAK及其相关蛋白可能在HS的形成过程中起着关键作用。该项目广泛的长期目标是解开压力诱导HS生长的信号通路。需要检验的假设是愈合伤口中HS形成的机械应变促进。(1)比较机械应变HS、正常人瘢痕和正常人真皮成纤维细胞(NHDF)中β1整合素、FAK和talin的时间磷酸化模式和肌球蛋白轻链激酶的激活。(2)描述酪氨酸激酶抑制对HS、正常人SCAR和NHDF中Beta1、整合素、FAK和talin酪氨酸磷酸化和MLCK活性的影响。(3)记录全身应用酪氨酸磷酸酶抑制剂原钒酸盐对紧致皮肤小鼠创面HS样结节肌成纤维细胞形成和创面收缩的影响，并与匹配的正常小鼠创面进行比较。

The disfiguring, dysfunctional hypertrophic scar (HS) in the highly strained tissue of a badly burned patient leaves an indelible impression. It is not well understood how high tissue-tension promotes HS, but it is clear that environmental strain regulates fibroblast gene expression, fibroblast alignment and extracellular matrix (ECM) morphology through integrin linked cell-cell and cell ECM interactions. Conformational changes in integrins mediate focal adhesion kinase (FAK) activation and subsequent phosphorylation of tyrosine residues. Therefore, FAK and associated proteins likely play a pivotal role in HS formation. The broad long-term objective of the project is to unravel the signaling pathways underlying strain induced HS growth. The hypothesis to be tested is mechanical strain promotion of HS formation in healed wounds. A novel in vitro mechanical strain device and tight-skin mouse wound-healing model will be used to investigate three aims: (1) Compare temporal phosphorylation patterning of beta1 integrin, FAK, and talin and myosin light chain kinase activation in mechanically strained HS, normal human scar and normal human dermal fibroblasts (NHDF). (2) Describe how tyrosine kinase inhibition affects phosphorylation of beta1, integrin, FAK, and talin tyrosine phosphorylation and MLCK activity in physically strained HS, normal human scar and NHDF. (3) Document how systemic administration of the tyrosine phosphatase inhibitor, orthovanadate, affects HS-like nodule myofibroblast formation and wound contraction in tight-skin mouse wounds and compare to matched normal mouse wounds.