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Role of PI3-kinase in anti-helminth immunity involving IgE and gastrointestinal mast cells

PI3激酶在涉及IgE和胃肠道肥大细胞的抗蠕虫免疫中的作用

基本信息

批准号：
18390155
负责人：
KOYASU Shigeo
金额：
$ 10.77万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18390155/
关键词：
p85α knockout mouse SCF c-kit integrin IgE AID MAdCAM-1 α4β7インテグリン IL-3 阻害剤 CD40 IL-4

项目摘要

We have previously shown that class IA phosphoinositide 3-kinase (PI3K) is important in the development of gastrointestinal mast cells and anti-helminth immunity against Strongyloides venezuelensis. Since gastrointestinal mast cells as well as IgE are important in anti-henminth immunity, we examined the role of class IA PI3K in gastrointestinal mast cell differentiation and IgE class stitch recombination using mice deficient for the p85α regulatory subunit of class IA PI3K. c-Kit signal was strongly impaired in p85α-deficient mast cells established from the bone marrow with IL-3 as proliferation and JNK activation in response to SCF was severely impaired in p85α-deficient cultured mast cells. Although the expression of a4 (37 integrin that is critical for cellular migration to the intestine was normal in p85α-deficient mast cells, the binding of a4137 to its ligand, MAdCAM was significantly weaker than that of wild type mast cells and migration of p85α-deficient mast cells as examined … More by haptotaxis on MAdCAM-1 coated surface in response to SCF was also impaired. We conclude from these observations that the lack of gastrointestinal mast cells in p85α-deficient mice is due to the deficiency in both migration to and survival in the intestine. Interestingly, helminth infection induced modest mastocytosis in p85α-deficient mice. It is known that IL-3 plays an important role in helminth-induced mastocytosis. PI3K/IL-3 double deficient mice were significantly more sensitive to the infection by S. venezuelensis than each single deficient mouse line as mastocytosis in the intestine and the induction of serum mMCP1 were severely impaired in double deficient mice. These results indicate that production of IL-3 likely supports mastocytosis in 85a-deficient mice. We also examined the role of PI3K in IgE production and found that p85α-deficient mice produced increasing amounts of serum IgE. Purified p85α-deficient B cells produced more IgE than wild type B cells in vitro in response to anti-CD40 mAb and IL-4. PI3K inhibitors wortmannin and IC87114 enhanced IgE production by wild type B cells stimulated with anti-CD40 mAb and IL-4. Under the same condition, antigen receptor cross-linking induced the expression of inhibitor of differentiation-2 (Id2) and suppressed the expression of activation induced cytidine deaminase (AID) and class switch recombination(CSR) in a PI3K-dependent manner. IgE production was also suppressed in a concentrated cell culture condition, which was completely reversed by PI3K inhibition. The selective suppression of IgE production by PI3K was also observed at a protein level after CSR. Our results indicate that PI3K negatively regulates IgE production at both CSR and protein levels. Less

我们之前已经证明IA类磷酸肌肽3-激酶（PI3K）在胃肠道肥大细胞的发育和对委内瑞拉圆线虫的抗蠕虫免疫中很重要。由于胃肠道肥大细胞和IgE在抗爬虫免疫中很重要，我们研究了IA类PI3K在胃肠道肥大细胞分化和IgE类重组中的作用，使用缺乏IA类PI3K的p85α调节亚基的小鼠。在含有IL-3的骨髓中建立的p85α缺陷肥大细胞中，c-Kit信号严重受损，而在培养的p85α缺陷肥大细胞中，细胞增殖和JNK激活对SCF的反应严重受损。尽管a4（37）整合素在p85α-缺陷肥大细胞中表达正常，但a4137与其配体MAdCAM的结合明显弱于野生型肥大细胞，并且p85α-缺陷肥大细胞的迁移能力也受到损害。我们从这些观察中得出结论，p85α-缺陷小鼠胃肠道肥大细胞的缺乏是由于向肠道的迁移和在肠道中的存活不足。有趣的是，蠕虫感染诱导p85α-缺陷小鼠适度肥大细胞增多。已知IL-3在蠕虫诱导的肥大细胞增多症中起重要作用。PI3K/IL-3双缺陷小鼠对委内瑞拉葡萄球菌感染的敏感性明显高于各单缺陷小鼠系，双缺陷小鼠肠道肥大细胞增生和血清mMCP1诱导功能严重受损。这些结果表明，在85a缺陷小鼠中，IL-3的产生可能支持肥大细胞增生。我们还研究了PI3K在IgE产生中的作用，发现p85α-缺陷小鼠产生的血清IgE量增加。纯化的p85α-缺陷B细胞在抗cd40单抗和IL-4的作用下比野生型B细胞产生更多的IgE。PI3K抑制剂wortmannin和IC87114通过抗cd40单抗和IL-4刺激野生型B细胞增强IgE的产生。在相同条件下，抗原受体交联诱导分化抑制剂-2 （Id2）的表达，并以pi3k依赖的方式抑制激活诱导胞苷脱氨酶（AID）和类开关重组酶（CSR）的表达。在细胞浓缩培养条件下，IgE的产生也受到抑制，而PI3K的抑制完全逆转了这种抑制。在CSR后，在蛋白水平上也观察到PI3K对IgE产生的选择性抑制。我们的研究结果表明，PI3K在CSR和蛋白水平上负调控IgE的产生。少