Sriramarao P, Anderson W, Wolitzky B A, Broide D H
Laboratory of Immunology and Vascular Biology, La Jolla Institute for Experimental Medicine, California, USA.
Lab Invest. 1996 Mar;74(3):634-43.
Increased numbers of mast cells are noted at sites of wound healing and inflammation. These mast cells are either recruited from the bone marrow or proliferate locally under cytokine stimulation. However, the molecular mechanisms mediating initial adhesive interactions between mast cell precursors and vascular endothelial cells are not well understood. We have used a syngeneic dorsal skinfold chamber model of microcirculation to study early events of mast cell-endothelial cell interactions by intravital fluorescence microscopy. Because "rolling" represents the earliest step of granulocyte adhesion under conditions of flow, our objective was to determine whether vascular selectins promote rolling of immature mouse bone marrow-derived mast cells (MBMMC) on endothelial cells lining murine blood vessels in vivo. In this study, titanium window chambers were implanted on the dorsal skinfolds of BALB/c mice. The passage of injected fluorescently labeled MBMMC within blood vessels of the striated skin muscle was observed by stroboscopic epi-illumination. As previously determined for other leukocytes, MBMMC were observed to roll in venules but not in arterioles or capillaries. Mice were also treated with neutralizing anti-E-selectin (mAb 9A9) and anti-P-selectin (mAb 5H1) antibodies and tested for their ability to block MBMMC rolling on venular endothelial cells. Intravenous administration of mAb 5H1 resulted in a marked decrease in MBMMC rolling, whereas mAb 9A9 and isotype matched control antibodies had no effect on the rolling flux of MBMMC. These studies represent the first identification of P-selectin as a rolling receptor for MBMMC, and demonstrate the use of a dorsal skinfold technique to study MBMMC-endothelial cell interactions under conditions of physiologic flow. Further studies will determine whether vascular selectins participate in the rolling and tissue recruitment of true circulating immature mast cell precursors in vivo.
在伤口愈合和炎症部位可观察到肥大细胞数量增加。这些肥大细胞要么从骨髓募集而来，要么在细胞因子刺激下在局部增殖。然而，介导肥大细胞前体与血管内皮细胞之间初始黏附相互作用的分子机制尚未完全明确。我们利用同基因背皮褶腔微循环模型，通过活体荧光显微镜研究肥大细胞与内皮细胞相互作用的早期事件。由于“滚动”是粒细胞在流动条件下黏附的最早步骤，我们的目的是确定血管选择素是否能促进未成熟小鼠骨髓来源的肥大细胞（MBMMC）在体内小鼠血管内皮细胞上滚动。在本研究中，将钛窗室植入BALB/c小鼠的背部皮褶。通过频闪落射照明观察注射了荧光标记的MBMMC在横纹皮肤肌肉血管内的通过情况。如先前对其他白细胞所确定的那样，观察到MBMMC在小静脉中滚动，但在小动脉或毛细血管中不滚动。还用中和抗E选择素（单克隆抗体9A9）和抗P选择素（单克隆抗体5H1）抗体处理小鼠，并测试它们阻断MBMMC在小静脉内皮细胞上滚动的能力。静脉注射单克隆抗体5H1导致MBMMC滚动显著减少，而单克隆抗体9A9和同型对照抗体对MBMMC的滚动通量没有影响。这些研究首次确定P选择素是MBMMC的滚动受体，并证明了利用背皮褶技术在生理流动条件下研究MBMMC与内皮细胞的相互作用。进一步的研究将确定血管选择素是否参与体内真正循环的未成熟肥大细胞前体的滚动和组织募集。
