Song Yinghui, Kumar Vivek, Wei Hua-Xing, Qiu Ju, Stanley Pamela
Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, 10461.
Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, 10461
J Immunol. 2016 Jan 1;196(1):232-43. doi: 10.4049/jimmunol.1402421. Epub 2015 Nov 25.
Lunatic, Manic, and Radical Fringe (LFNG, MFNG, and RFNG) are N-acetylglucosaminyltransferases that modify Notch receptors and regulate Notch signaling. Loss of LFNG affects thymic T cell development, and LFNG and MFNG are required for marginal zone (MZ) B cell development. However, roles for MFNG and RFNG in T cell development, RFNG in B cell development, or Fringes in T and B cell activation are not identified. In this study, we show that Lfng/Mfng/Rfng triple knockout (Fng tKO) mice exhibited reduced binding of DLL4 Notch ligand to CD4/CD8 double-negative (DN) T cell progenitors, and reduced expression of NOTCH1 targets Deltex1 and CD25. Fng tKO mice had reduced frequencies of DN1/cKit(+) and DN2 T cell progenitors and CD4(+)CD8(+) double-positive (DP) T cell precursors, but increased frequencies of CD4(+) and CD8(+) single-positive T cells in the thymus. In spleen, Fng tKO mice had reduced frequencies of CD4(+), CD8(+), central memory T cells and MZ B cells, and an increased frequency of effector memory T cells, neutrophils, follicular, and MZ P B cells. The Fng tKO phenotype was cell-autonomous and largely rescued in mice expressing one allele of a single Fng gene. Stimulation of Fng tKO splenocytes with anti-CD3/CD28 beads or LPS gave reduced proliferation compared with controls, and the generation of activated T cells by Concanavalin A or L-PHA was also reduced in Fng tKO mice. Therefore, each Fringe contributes to T and B cell development, and Fringe is required for optimal in vitro stimulation of T and B cells.
Lunatic、Manic和Radical Fringe（LFNG、MFNG和RFNG）是N-乙酰葡糖胺基转移酶，可修饰Notch受体并调节Notch信号通路。LFNG的缺失会影响胸腺T细胞发育，而边缘区（MZ）B细胞发育需要LFNG和MFNG。然而，MFNG和RFNG在T细胞发育中的作用、RFNG在B细胞发育中的作用，或者Fringe在T和B细胞激活中的作用尚未明确。在本研究中，我们发现Lfng/Mfng/Rfng三敲除（Fng tKO）小鼠中，DLL4 Notch配体与CD4/CD8双阴性（DN）T细胞祖细胞的结合减少，NOTCH1靶标Deltex1和CD25的表达降低。Fng tKO小鼠胸腺中DN1/cKit(+)和DN2 T细胞祖细胞以及CD4(+)CD8(+)双阳性（DP）T细胞前体的频率降低，但CD4(+)和CD8(+)单阳性T细胞的频率增加。在脾脏中，Fng tKO小鼠的CD4(+)、CD8(+)、中枢记忆T细胞和MZ B细胞频率降低，效应记忆T细胞、中性粒细胞、滤泡和MZ P B细胞频率增加。Fng tKO表型具有细胞自主性，在表达单个Fng基因一个等位基因的小鼠中基本得到挽救。与对照相比，用抗CD3/CD28磁珠或LPS刺激Fng tKO脾细胞增殖减少，Fng tKO小鼠中伴刀豆球蛋白A或L-PHA激活T细胞的生成也减少。因此，每种Fringe都对T和B细胞发育有贡献，并且Fringe是T和B细胞体外最佳刺激所必需的。
