New Regulatory Roles of Galectin-3 in High-Affinity IgE Receptor Signaling
New Regulatory Roles of Galectin-3 in High-Affinity IgE Receptor Signaling
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DOI：
10.1128/mcb.00064-16
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发表时间：
2016-05-01
影响因子：
5.3
通讯作者：
Draber, Petr
中科院分区：
文献类型：
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作者：
Bambouskova, Monika;Polakovicova, Iva;Draber, Petr
肥大细胞中IgE的高亲和力受体（Fc β RI）的聚集启动激活事件，导致脱粒和炎症介质的释放。为了更好地了解肥大细胞激活的信号通路和基因，我们开发了一种高通量肥大细胞脱粒试验，适用于使用基于慢病毒的短发夹RNA（shRNA）递送的RNA干扰实验。我们测试了432个针对144个选定基因的shRNA对Fc ε RI介导的肥大细胞脱粒的影响，并确定了15个潜在的调节因子。在进一步的研究中，我们专注于半乳糖凝集素-3（Gal 3），在这项研究中被鉴定为肥大细胞脱粒的负调节剂。Gal 3敲低的Fc γ-受体抑制剂激活的细胞表现出脾酪氨酸激酶和其他几种信号转导分子的酪氨酸磷酸化上调和钙应答增强。我们发现Gal 3促进IgE-Fc β RI复合物的内化，这可能与我们发现Gal 3是Fc β RI泛素化的正调节因子有关。此外，我们发现Gal 3促进肥大细胞在纤连蛋白上的粘附和运动，但负调节抗原诱导的趋化性。组合数据表明Gal 3参与肥大细胞中Fc γ RI介导的信号传导事件的正调控和负调控。
Aggregation of the high-affinity receptor for IgE (Fc epsilon RI) in mast cells initiates activation events that lead to degranulation and release of inflammatory mediators. To better understand the signaling pathways and genes involved in mast cell activation, we developed a high-throughput mast cell degranulation assay suitable for RNA interference experiments using lentivirus-based short hairpin RNA (shRNA) delivery. We tested 432 shRNAs specific for 144 selected genes for effects on Fc epsilon RI-mediated mast cell degranulation and identified 15 potential regulators. In further studies, we focused on galectin-3 (Gal3), identified in this study as a negative regulator of mast cell degranulation. Fc epsilon RI-activated cells with Gal3 knockdown exhibited upregulated tyrosine phosphorylation of spleen tyrosine kinase and several other signal transduction molecules and enhanced calcium response. We show that Gal3 promotes internalization of IgE-Fc epsilon RI complexes; this may be related to our finding that Gal3 is a positive regulator of Fc epsilon RI ubiquitination. Furthermore, we found that Gal3 facilitates mast cell adhesion and motility on fibronectin but negatively regulates antigen-induced chemotaxis. The combined data indicate that Gal3 is involved in both positive and negative regulation of Fc epsilon RI-mediated signaling events in mast cells.