Macrophages as modulators of repair after neonatal stroke

描述（由申请人提供）：成人或新生儿中风后有自我修复的潜力，但内源性神经发生是短暂的和无效的。我们的目标是加强新生儿中风后的修复。成人中风后血管新生通过形成“神经血管生态位”促进神经新生。脑巨噬细胞可以通过影响脑微环境和直接影响血管生成和神经发生来调节脑卒中后的修复和功能恢复。半乳糖凝集素-3 （Gal-3）最近被认为与血管生成过程有关。假定Gal-3能够为神经血管生态位的形成提供一个“对接点”，并介导vegf诱导的血管生成，这使该分子成为增强修复的一个有吸引力的靶点，但其对新生儿中风后修复的影响尚不清楚。我们假设小胶质细胞/巨噬细胞对新生儿中风后的长期恢复有重要影响，部分是通过增强gal -3依赖性血管生成。利用我们建立的新生大鼠和小鼠大脑中动脉短暂性闭塞模型，我们将确定血管生成和神经发生是否依赖于脑巨噬细胞中产生的Gal-3。在目的1中，我们将确定小胶质细胞耗竭对新生儿中风后血管生成和神经血管生态位形成的影响。我们将通过生物发光来监测活体动物的轴突生长。在Aim 2中，我们将通过特定分子探针靶向vss3整合素的超声增强来研究Gal-3信号增强或中断对活体大鼠内皮细胞激活的影响。在TLR2启动子下携带双luc/gfp报告基因的新生儿缺血性Gal-3敲除小鼠中，修复将被进一步研究。在Aim 3中，我们将通过超声和VEGFR2特异性探针描绘损伤活鼠在Gal-3或VEGFR2抑制后神经血管生态位的形成。vegf介导的血管生成将在受损的Gal-3敲除小鼠中进行测定。新生儿中风后小胶质细胞耗竭和Gal-3操作的功能后果将被确定。了解调节修复的机制是成功的从床到床的翻译，以增强受伤新生儿大脑的修复的重要的第一步。

DESCRIPTION (provided by applicant): There is a potential for self-repair after adult or neonatal stroke, but endogenous neurogenesis is short- lived and ineffective. Our goal is to enhance the repair after neonatal stroke. Angiogenesis facilitates neurogenesis after adult stroke through the formation of a "neurovascular niche." Brain macrophages can modulate repair and functional recovery after stroke through effects on the brain microenvironment and direct effects on angiogenesis and neurogenesis. Galectin-3 (Gal-3) has recently been implicated in the process of angiogenesis. The postulated ability of Gal-3 to provide a "docking point" for the formation of a neurovascular niche and to mediate VEGF-induced angiogenesis makes this molecule an attractive target for enhancing repair, but its effect on repair after neonatal stroke is not known. We hypothesize that microglia/macrophages critically affect long-term recovery after neonatal stroke, in part through enhanced Gal-3-dependent angiogenesis. Using our established models of transient middle cerebral artery occlusion in neonatal rats and mice, we wil determine whether angiogenesis and neurogenesis depend on Gal-3 produced in brain macrophages. In Aim 1, we will determine the effects of microglial depletion on angiogenesis and neurovascular niche formation after neonatal stroke. We will monitor axonal outgrowth in living animals by bioluminescence. In Aim 2, we will investigate the effects of enhanced or disrupted Gal-3 signaling on endothelial activation in living rats by ultrasound enhanced with specific molecular probes to target �vss3 integrin. Repair will be further studied in neonatal ischemic Gal-3 knockout mice bearing the dual luc/gfp reporter under the TLR2 promoter. In Aim 3, we will delineate neurovascular niche formation folowing Gal-3 or VEGFR2 inhibition in injured living rats by using ultrasound and specific probes for VEGFR2. VEGF-mediated angiogenesis will be determined in injured Gal-3 knockout mice. Functional consequences of microglial depletion and Gal-3 manipulations after neonatal stroke will be determined. Understanding the mechanisms regulating repair is an important first step on the way to successful bench-to-bed translation to enhance repair in injured newborn brains.