Molecular Immunopharmacology and Drug Discovery Laboratory, Department of Molecular Physiology and Pharmacology, Tufts University School of Medicine, Boston, MA 02111, USA.
J Allergy Clin Immunol. 2011 Jun;127(6):1522-31.e8. doi: 10.1016/j.jaci.2011.02.005. Epub 2011 Mar 31.
Mast cells derive from hematopoietic cell precursors and participate in tissue allergic, immune, and inflammatory processes. They secrete many mediators, including preformed TNF, in response to allergic, neuropeptide, and environmental triggers. However, regulation of mast cell degranulation is not well understood.
We investigated the role of mitochondrial dynamics in degranulation of human cultured mast cells.
Human umbilical cord blood-derived mast cells (hCBMCs) and Laboratory of Allergic Diseases 2 (LAD2) mast cells were examined by confocal and differential interference contrast microscopy during activation by IgE/antigen and substance P (SP). Mast cells in control and atopic dermatitis (AD) skin were evaluated by transmission electron microscopy. LAD2 cells were pretreated with mitochondrial division inhibitor, a dynamin-related protein 1 (Drp1) inhibitor, and small interfering RNA for Drp1, which is necessary for mitochondrial fission and translocation. Calcineurin and Drp1 gene expression was analyzed in stimulated LAD2 cells and AD skin biopsies.
Stimulation of hCBMCs with IgE/antigen or LAD2 cells with SP leads to rapid (30 minutes) secretion of preformed TNF. Degranulation is accompanied by mitochondrial translocation from a perinuclear location to exocytosis sites. Extracellular calcium depletion prevents these effects, indicating calcium requirement. The calcium-dependent calcineurin and Drp1 are activated 30 minutes after SP stimulation. Reduction of Drp1 activity by mitochondrial division inhibitor and decrease of Drp1 expression using small interfering RNA inhibit mitochondrial translocation, degranulation, and TNF secretion. Mitochondrial translocation is also evident by transmission electron microscopy in skin mast cells from AD biopsies, in which gene expression of calcineurin, Drp1, and SP is higher than in normal skin.
Human mast cell degranulation requires mitochondrial dynamics, also implicated in AD.
肥大细胞来源于造血细胞前体，参与组织过敏、免疫和炎症过程。它们响应过敏、神经肽和环境触发因素，分泌许多介质，包括预先形成的 TNF。然而，肥大细胞脱颗粒的调节机制尚不清楚。
我们研究了线粒体动力学在人培养肥大细胞脱颗粒中的作用。
通过共聚焦和微分干涉对比显微镜观察人脐血衍生的肥大细胞（hCBMC）和实验室过敏病 2 （LAD2）肥大细胞在 IgE/抗原和 P 物质（SP）激活期间的脱颗粒情况。通过透射电子显微镜评估对照和特应性皮炎（AD）皮肤中的肥大细胞。用线粒体分裂抑制剂、一种与动力蛋白相关蛋白 1（Drp1）抑制剂和 Drp1 的小干扰 RNA 预处理 LAD2 细胞，后者对于线粒体裂变和易位是必需的。分析刺激的 LAD2 细胞和 AD 皮肤活检中的钙调神经磷酸酶和 Drp1 基因表达。
用 IgE/抗原刺激 hCBMC 或用 SP 刺激 LAD2 细胞导致预先形成的 TNF 快速（30 分钟）分泌。脱颗粒伴随着线粒体从核周位置向胞吐部位的易位。细胞外钙耗竭可防止这些作用，表明钙的需求。钙依赖性钙调神经磷酸酶和 Drp1 在 SP 刺激后 30 分钟被激活。线粒体分裂抑制剂降低 Drp1 活性和小干扰 RNA 降低 Drp1 表达抑制线粒体易位、脱颗粒和 TNF 分泌。AD 活检皮肤肥大细胞中的透射电子显微镜也显示了线粒体易位，其中钙调神经磷酸酶、Drp1 和 SP 的基因表达高于正常皮肤。
人肥大细胞脱颗粒需要线粒体动力学，这也与 AD 有关。
