Chang Claire W, Cheng Ni, Bai Yanyan, Skidgel Randal A, Du Xiaoping
Department of Pharmacology, University of Illinois at Chicago, Chicago, IL.
Department of Bioengineering, University of Illinois at Chicago, Chicago, IL; and.
J Immunol. 2021 Dec 15;207(12):3038-3049. doi: 10.4049/jimmunol.2001385. Epub 2021 Nov 19.
Neutrophil migration requires β integrins and chemoattractant receptor signaling for motility and directionality. G protein subunit Gα can facilitate cell migration by mediating RhoA activation induced by G protein-coupled receptors. However, the possible role of Gα-integrin interaction in migration is unclear. In this study, we show that Gα neutrophils are deficient in transendothelial migration and migration on β integrin ligand ICAM-1. However, unlike G protein-coupled receptors and integrin inside-out signaling pathways, Gα is important in migration velocity and neutrophil spreading but not in directionality nor cell adhesion. Importantly, neutrophil recruitment in vivo was also inhibited in Gα mice, suggesting the importance of Gα in transendothelial migration of neutrophils in vitro and in vivo. Furthermore, a synthetic peptide (MB2mP6) derived from the Gα binding site of β inhibited Gα-β interaction and Gα-mediated transient RhoA inhibition in neutrophils, suggesting that this peptide inhibited integrin outside-in signaling. MB2mP6 inhibited migration of control neutrophils through endothelial cell monolayers or ICAM-1-coated filters, but was without further effect on Gα neutrophils. It also inhibited integrin-dependent neutrophil migration velocity without affecting directionality. In vivo, MB2mP6 markedly inhibited neutrophil infiltration into the cardiac tissues induced by ischemia/reperfusion injury. Thus, Gα-dependent outside-in signaling enables integrin-dependent neutrophil motility without affecting directionality and may be a new therapeutic target for inhibiting neutrophil trafficking but not adhesion.
中性粒细胞迁移需要β整合素和趋化因子受体信号来实现运动性和方向性。G蛋白亚基Gα可通过介导G蛋白偶联受体诱导的RhoA激活来促进细胞迁移。然而，Gα-整合素相互作用在迁移中的可能作用尚不清楚。在本研究中，我们发现Gα缺陷的中性粒细胞在内皮迁移以及在β整合素配体ICAM-1上的迁移存在缺陷。然而，与G蛋白偶联受体和整合素外向内信号通路不同，Gα在迁移速度和中性粒细胞铺展中起重要作用，但在方向性和细胞黏附中不起作用。重要的是，Gα缺陷小鼠体内的中性粒细胞募集也受到抑制，这表明Gα在中性粒细胞体外和体内的跨内皮迁移中具有重要作用。此外，一种源自β的Gα结合位点的合成肽（MB2mP6）可抑制中性粒细胞中Gα-β相互作用以及Gα介导的RhoA瞬时抑制，这表明该肽抑制了整合素内向内信号。MB2mP6抑制对照中性粒细胞通过内皮细胞单层或ICAM-1包被滤膜的迁移，但对Gα缺陷的中性粒细胞没有进一步影响。它还抑制整合素依赖性中性粒细胞迁移速度，但不影响方向性。在体内，MB2mP6显著抑制缺血/再灌注损伤诱导的中性粒细胞向心脏组织的浸润。因此，Gα依赖性内向内信号使整合素依赖性中性粒细胞具有运动性，而不影响方向性，可能是抑制中性粒细胞转运而非黏附的新治疗靶点。
