Mahoney Edward T, Benton Richard L, Maddie Melissa A, Whittemore Scott R, Hagg Theo
Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA.
J Comp Neurol. 2009 Jan 10;512(2):243-55. doi: 10.1002/cne.21902.
Endothelial cell (EC) loss and subsequent angiogenesis occur over the first week after spinal cord injury (SCI). To identify molecular mechanisms that could be targeted with intravenous (i.v.) treatments, we determined whether transmembrane "a disintegrin and metalloprotease" (ADAM) proteins are expressed in ECs of the injured spinal cord. ADAMs bind to integrins, which are important for EC survival and angiogenesis. Female adult C57Bl/6 mice with a spinal cord contusion had progressively more ADAM8 (CD156) immunostaining in blood vessels and individual ECs between 1 and 28 days following injury. Uninjured spinal cords had little ADAM8 staining. The increase in ADAM8 mRNA and protein was confirmed in spinal cord lysates, and ADAM8 mRNA was present in FACS-enriched ECs. ADAM8 colocalized extensively and exclusively with the EC marker PECAM and also with i.v.-injected lectins. Intravenous isolectin B4 (IB4) labels a subpopulation of blood vessels at and within the injury epicenter 3-7 days after injury, coincident with angiogenesis. Both ADAM8 and the proliferation marker Ki-67 were present in IB4-positive microvessels. ADAM8-positive proliferating cells were seen at the leading end of IB4-positive blood vessels. Angiogenesis was confirmed by BrdU incorporation, binding of i.v.-injected nucleolin antibodies, and MT1-MMP immunostaining in a subset of blood vessels. These data suggest that ADAM8 is vascular selective and plays a role in proliferation and/or migration of ECs during angiogenesis following SCI.
脊髓损伤（SCI）后的第一周内会发生内皮细胞（EC）丢失及随后的血管生成。为了确定可通过静脉注射（i.v.）治疗靶向作用的分子机制，我们研究了跨膜“解聚素和金属蛋白酶”（ADAM）蛋白是否在脊髓损伤部位的内皮细胞中表达。ADAM与整合素结合，而整合素对内皮细胞存活和血管生成至关重要。成年雌性C57Bl/6小鼠脊髓挫伤后1至28天，血管和单个内皮细胞中的ADAM8（CD156）免疫染色逐渐增多。未受伤的脊髓几乎没有ADAM8染色。脊髓裂解物中ADAM8 mRNA和蛋白的增加得到证实，且在通过荧光激活细胞分选（FACS）富集的内皮细胞中存在ADAM8 mRNA。ADAM8与内皮细胞标志物血小板内皮细胞黏附分子（PECAM）广泛且特异性地共定位，也与静脉注射的凝集素共定位。静脉注射异凝集素B4（IB4）可标记损伤后3至7天损伤中心及其内部的一部分血管，这与血管生成时间一致。ADAM8和增殖标志物Ki-67均存在于IB4阳性微血管中。在IB4阳性血管的前端可见ADAM8阳性增殖细胞。通过5-溴脱氧尿嘧啶核苷（BrdU）掺入、静脉注射核仁素抗体结合以及一部分血管中的基质金属蛋白酶-1（MT1-MMP）免疫染色证实了血管生成。这些数据表明，ADAM8具有血管选择性，在脊髓损伤后血管生成过程中在内皮细胞的增殖和/或迁移中发挥作用。
