Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
School of Clinical Medicine, UNSW Medicine and Health, University of New South Wales Sydney, Kensington, NSW 2052, Australia.
Int J Mol Sci. 2023 Jul 14;24(14):11475. doi: 10.3390/ijms241411475.
Transglutaminase 2 (TG2) plays a role in cellular processes that are relevant to wound healing, but to date no studies of wound healing in TG2 knockout mice have been reported. Here, using 129T2/SvEmsJ (129)- or C57BL/6 (B6)-backcrossed TG2 knockout mice, we show that TG2 facilitates murine wound healing in a strain-dependent manner. Early healing of in vivo cutaneous wounds and closure of in vitro scratch wounds in murine embryonic fibroblast (MEF) monolayers were delayed in 129, but not B6, TG2 knockouts, relative to their wild-type counterparts, with wound closure in 129 being faster than in B6 wild-types. A single dose of exogenous recombinant wild-type TG2 to 129 TG2 mice or MEFs immediately post-wounding accelerated wound closure. Neutrophil and monocyte recruitment to 129 cutaneous wounds was not affected by deletion up to 5 days post-wounding. mRNA and TG2 protein abundance were higher in 129 than in B6 wild-types and increased in abundance following cutaneous and scratch wounding. and factor XIIA () mRNA abundance increased post-wounding, but there was no compensation by TG family members in TG2 relative to TG2 mice in either strain before or after wounding. 129 TG2 MEF adhesion was greater and spreading was faster than that of B6 TG2 MEFs, and was dependent on syndecan binding in the presence, but not absence, of RGD inhibition of integrin binding. Adhesion and spreading of 129, but not B6, TG2 MEFs was impaired relative to their wild-type counterparts and was accelerated by exogenous addition or transfection of TG2 protein or cDNA, respectively, and was independent of the transamidase or GTP-binding activity of TG2. Rho-family GTPase activation, central to cytoskeletal organization, was altered in 129 TG2 MEFs, with delayed RhoA and earlier Rac1 activation than in TG2 MEFs. These findings indicate that the rate of wound healing is different between 129 and B6 mouse strains, correlating with TG2 abundance, and although not essential for wound healing, TG2 facilitates integrin- and syndecan-mediated RhoA- and Rac1-activation in fibroblasts to promote efficient wound contraction.
转谷氨酰胺酶 2（TG2）在与伤口愈合相关的细胞过程中发挥作用，但迄今为止，尚未有关于 TG2 基因敲除小鼠伤口愈合的研究报告。在这里，我们使用 129T2/SvEmsJ（129）或 C57BL/6（B6）回交 TG2 基因敲除小鼠，表明 TG2 以依赖于品系的方式促进小鼠伤口愈合。体内皮肤伤口的早期愈合和体外单层鼠胚胎成纤维细胞（MEF）划痕伤口的闭合在 129 中延迟，但在 B6 中不延迟，与野生型相比，129 的伤口闭合更快。在创伤后立即向 129 TG2 小鼠或 MEF 给予外源性重组野生型 TG2 可加速伤口闭合。在创伤后 5 天内，中性粒细胞和单核细胞向 129 皮肤伤口的募集不受缺失的影响。与 B6 野生型相比，129 的 mRNA 和 TG2 蛋白丰度更高，并且在皮肤和划痕创伤后增加。在两种品系中，创伤后 和因子 XIIA（）mRNA 丰度增加，但在创伤前或创伤后，TG2 相对于 TG2 小鼠，TG 家族成员的丰度没有代偿。129 TG2 MEF 的黏附和铺展速度大于 B6 TG2 MEF，并且在存在 syndecan 结合的情况下依赖于整合素结合，但在不存在 RGD 抑制整合素结合的情况下则不然。129 的黏附和铺展相对于其野生型对照受损，但通过外源性添加或转染 TG2 蛋白或 cDNA 分别得到加速，并且独立于 TG2 的转胺酶或 GTP 结合活性。细胞骨架组织中的核心 Rho 家族 GTPase 激活在 129 TG2 MEF 中发生改变，与 TG2 MEF 相比，RhoA 激活延迟，Rac1 激活更早。这些发现表明，129 和 B6 小鼠品系之间的伤口愈合速度不同，与 TG2 丰度相关，尽管不是伤口愈合所必需的，但 TG2 促进整合素和 syndecan 介导的 RhoA 和 Rac1 激活，以促进有效的伤口收缩。
