Centre de Recherche en Rhumatologie et Immunologie du Centre Hospitalier Universitaire de Québec, Department of Microbiology-Infectiology and Immunology, Faculty of Medicine, Laval University, Quebec, Canada.
FASEB J. 2010 Jun;24(6):2116-25. doi: 10.1096/fj.09-146167. Epub 2010 Feb 12.
We shed new light on the expression and function of the proteinase-activated receptor (PAR) family, associated with inflammation and hyperalgesia, in human granulocytes. Resting cells expressed constitutive levels of PAR-2 and PAR-3 mRNA but not PAR-1 or PAR-4. Based on flow cytometry, stimulation with opsonized bacteria (Bop) specifically up-regulated cell surface expression of PAR-2 in a concentration-dependent and time-dependent manner, independent of transcription or de novo protein synthesis. Primary granules were identified as a source of preformed PAR-2 that can readily be mobilized at the surface on fusion with the plasma membrane. Cellular response to PAR-2 activation, measured as changes in intracellular calcium concentration, was enhanced in PAR-2 up-regulated cells. Increase of cell-surface PAR-2 and of cell responsiveness were dependent specifically on the engagement of immunoglobulin (Ig)-binding receptors. Together, our results reveal that mobilization of intracellular granules, in response to Ig-receptor activation, up-regulates PAR-2 surface expression and makes neutrophils more responsive to proteinase activity. This enhanced response to PAR-2 activation indicates that molecular communication between pain and inflammation may be more important than previously believed.
我们深入研究了与炎症和痛觉过敏相关的蛋白酶激活受体（PAR）家族在人嗜中性粒细胞中的表达和功能。静止细胞表达组成型 PAR-2 和 PAR-3 mRNA，但不表达 PAR-1 或 PAR-4。基于流式细胞术，用调理细菌（Bop）刺激可特异性地上调 PAR-2 的细胞表面表达，呈浓度和时间依赖性，而不依赖于转录或从头蛋白质合成。初级颗粒被鉴定为预先形成的 PAR-2 的来源，可在与质膜融合时迅速在表面被动员。通过测量细胞内钙离子浓度的变化来测量细胞对 PAR-2 激活的反应，在 PAR-2 上调的细胞中增强。细胞表面 PAR-2 和细胞反应性的增加特异性地依赖于免疫球蛋白（Ig）结合受体的参与。总之，我们的研究结果揭示了细胞内颗粒对 Ig 受体激活的反应，可上调 PAR-2 的表面表达，使嗜中性粒细胞对蛋白酶活性更敏感。这种对 PAR-2 激活的增强反应表明，疼痛和炎症之间的分子通讯可能比以前认为的更为重要。
