PgmNr Z611: Macrophages mediate the repair of brain vascular rupture through direct physical adhesion and mechanical traction.

Authors:
Lingfei Luo 1 ; Chi Liu 1 ; Chuan Wu 1 ; Qifen Yang 1 ; Jing Gao 2 ; Li Li 1 ; Deqin Yang 2


Institutes
1) School of Life Sciences, Southwest University, Chongqing, China; 2) The Affiliated Hospital of Stomatology, Chongqing Medical University, Chongqing, China.


Abstract:

Hemorrhagic stroke and brain microbleeds are caused by cerebrovascular ruptures. Fast repair of such ruptures is the most promising therapeutic approach. Due to a lack of high resolution in vivo real-time studies, the dynamic cellular events involved in cerebrovascular repair remain unknown. Here, we have developed a cerebrovascular rupture system in zebrafish using multi-photon laser, which generates a lesion with two endothelial ends. In vivo time-lapse imaging showed that a macrophage arrives at the lesion and extended filopodia or lamellipodia to physically adhere to both endothelial ends. This macrophage generated mechanical traction forces to pull the endothelial ends and facilitate their ligation, thus mediating the repair of the rupture. Both depolymerization of microfilaments and inhibition of phosphatidylinositide 3-kinase or Rac1 activity disrupted macrophage-endothelial adhesion and impaired cerebrovascular repair. Our study reveals a hitherto unexpected role for macrophage in mediating repair of cerebrovascular ruptures through direct physical adhesion and mechanical traction..