Oh Sun Young, Brandal Stephanie, Kapur Reuben, Zhu Zhou, Takemoto Clifford M
Division of Allergy and Clinical Immunology, Johns Hopkins Allergy and Asthma Center, Baltimore, MD, USA.
Division of Pediatric Hematology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Exp Hematol. 2014 Oct;42(10):919-23.e1. doi: 10.1016/j.exphem.2014.07.266. Epub 2014 Sep 6.
MicroRNAs (miRNAs) are small, noncoding RNAs that have been shown to play a critical role in normal physiology and disease, such as hematopoietic development and cancer. However, their role in mast-cell function and development is poorly understood. The major objective of this study was to determine how global miRNA expression affects mast-cell physiology. The RNase III endonuclease, Dicer, is required for the processing of pre-miRNAs into mature miRNAs. To investigate the effect of global miRNA depletion on mast cells in vivo, we generated a mast-cell-specific knock out of Dicer in mice. Transgenic mice (Mcpt5-Cre) that express Cre selectively in connective tissue mast cells were crossed with mice carrying the floxed conditional Dicer allele (Dicer fl/fl). Mcpt5-Cre × Dicer fl/fl mice with homozygous Dicer gene deletion in mast cells were found to have a profound mast-cell deficiency with near complete loss of peritoneal, gastrointestinal, and skin mast cells. We examined the in vivo functional consequence of mast-cell-specific Dicer deletion using an immunoglobulin-E-dependent passive systemic anaphylaxis murine model. Immunoglobulin-E-sensitized wild type Mcpt5-Cre × Dicer +/+ and heterozygous Mcpt5-Cre × Dicer fl/+ mice show marked hypothermia with antigen; however, homozygous Mcpt5-Cre × Dicer fl/fl mice were completely unresponsive to antigen challenge. These studies suggest a critical role for Dicer and miRNA expression for establishment of tissue compartments of functional mast cells in vivo.
微小RNA（miRNA）是一类小的非编码RNA，已被证明在正常生理和疾病（如造血发育和癌症）中起关键作用。然而，它们在肥大细胞功能和发育中的作用却知之甚少。本研究的主要目的是确定整体miRNA表达如何影响肥大细胞生理。RNase III核酸内切酶Dicer是将前体miRNA加工成成熟miRNA所必需的。为了研究整体miRNA缺失对体内肥大细胞的影响，我们构建了小鼠肥大细胞特异性Dicer基因敲除模型。在结缔组织肥大细胞中选择性表达Cre的转基因小鼠（Mcpt5-Cre）与携带floxed条件性Dicer等位基因（Dicer fl/fl）的小鼠杂交。发现肥大细胞中Dicer基因纯合缺失的Mcpt5-Cre×Dicer fl/fl小鼠存在严重的肥大细胞缺陷，腹膜、胃肠道和皮肤肥大细胞几乎完全丧失。我们使用免疫球蛋白E依赖性被动全身过敏反应小鼠模型检查了肥大细胞特异性Dicer缺失的体内功能后果。免疫球蛋白E致敏的野生型Mcpt5-Cre×Dicer +/+和杂合Mcpt5-Cre×Dicer fl/+小鼠在接触抗原后出现明显体温过低；然而，纯合Mcpt5-Cre×Dicer fl/fl小鼠对抗原刺激完全无反应。这些研究表明Dicer和miRNA表达对于体内功能性肥大细胞组织区室的建立起关键作用。
