FcεRIα is responsible for high-affinity binding with the Fc portion of IgE, which is critical for IgE-dependent disease responses such as allergy responses and anti-parasite immunity. FcεRIα is expressed on a few cell types, including mast cells and basophils.
Functioned as α-subunit of the high-affinity immunoglobulin E receptor (Fcε RIα), Fcε RIα plays a central role in the pathogenesis of Ig-E-mediated allergy and other IgE-related disorders. Fcε RIα is normally expressed only in limited spectrum of cells like basophils and mast cells, but the mechanism of controlling Fcε RIα expression in these cells is less well understood. In this study, we found fully overlapped natural antisense transcript (NATs) of Fcε RIα ( FCER1A -AS) is co-expressed with cognate sense transcript ( FCER1A -S) in IL-3 induced Fcε RIα-expressing cells or in high Fcε RIα-expressing cell line MC/9. When FCER1A -AS is selectively knocked down by CRISPR/RfxCas13d (CasRx) approach in MC/9, expression of mRNA and proteins of FCER1A -S is also markedly decreased. Furthermore, deficiency of FCER1A -AS along with lack of FCER1A -S expression is found in two different lines of gene-targeted mice in which FCER1A locus is disturbed at different sites. More importantly, the FCER1A -AS-deficient homozygous mice display similarly diminished anaphylactic reaction as FCER1A gene knockout mice. Thus, we uncovered in this investigation that the expression of FCER1A -S is positively regulated by co-expressed fully overlapped antisense transcript.
目的 探究细胞因子IL-4抑制骨髓细胞分化产生嗜碱性粒细胞的能力及机制.方法 采用IL-3诱导培养小鼠骨髓细胞,流式细胞术检测FcεRIα+ckit-CD49b+嗜碱性粒细胞以及FcεRIα+ckit-CD49b-新发现的单阳细胞群,并用Ki67检测其增殖状态.流式细胞术分选单阳细胞群后继续用IL-3诱导培养,以确定其后续分化能力.结果 经IL-3诱导培养的骨髓细胞,3～4d后开始有嗜碱性粒细胞出现,至第9天细胞比例达到高峰,然后开始下降.与野生型相比,IL-4缺陷的骨髓细胞诱导出的嗜碱性粒细胞,无论是在细胞比例或数目还是该细胞表达FcεRIα的平均荧光强度都显著增加.在IL-4缺陷型骨髓细胞诱导过程中加入外源重组IL-4可抑制嗜碱性粒细胞的产生;而在野生型骨髓细胞诱导过程中加入抗IL-4抗体则可增加嗜碱性粒细胞的产生,提示诱导过程中产生的IL-4具有负向调控嗜碱性粒细胞形成的作用.与野生型相比,IL-4缺陷鼠骨髓细胞经诱导可产生更多未曾报道过的表型为FcεRIα+ckit-CD49b-的单阳细胞群,且该细胞群的Ki67阳性率更高.单阳细胞群经IL-3刺激后可继续分化出嗜碱性粒细胞.结论 IL-3诱导培养骨髓细胞过程中,内源产生的IL-4可抑制嗜碱性粒细胞的产生及FcεRIα 的表达水平.
