Invariant natural killer T (iNKT) cells are highly conserved innate-like T lymphocytes that originate from CD4⁺CD8⁺ double-positive (DP) thymocytes. Here, we report that serine/arginine splicing factor 1 (SRSF1) intrinsically regulates iNKT cell development by directly targeting Myb and balancing the abundance of short and long isoforms. Conditional ablation of SRSF1 in DP cells led to a substantially diminished iNKT cell pool due to defects in proliferation, survival, and TCRα rearrangement. The transition from stage 0 to stage 1 of iNKT cells was substantially blocked, and the iNKT2 subset was notably diminished in SRSF1-deficient mice. SRSF1 deficiency resulted in aberrant expression of a series of regulators that are tightly correlated with iNKT cell development and iNKT2 differentiation, including Myb, PLZF, Gata3, ICOS, and CD5. In particular, we found that SRSF1 directly binds and regulates pre-mRNA alternative splicing of Myb and that the expression of the short isoform of Myb is substantially reduced in SRSF1-deficient DP and iNKT cells. Strikingly, ectopic expression of the Myb short isoform partially rectified the defects caused by ablation of SRSF1. Furthermore, we confirmed that the SRSF1-deficient mice exhibited resistance to acute liver injury upon α-GalCer and Con A induction. Our findings thus uncovered a previously unknown role of SRSF1 as an essential post-transcriptional regulator in iNKT cell development and functional differentiation, providing new clinical insights into iNKT-correlated disease.

不变的自然杀伤 T (iNKT) 细胞是高度保守的先天样 T 淋巴细胞，源自 CD4 ⁺ CD8 ⁺双阳性 (DP) 胸腺细胞。在这里，我们报告丝氨酸/精氨酸剪接因子 1 (SRSF1) 通过直接靶向 Myb 并平衡短和长亚型的丰度，从本质上调节 iNKT 细胞的发育。由于增殖、存活和 TCRα 重排缺陷，DP 细胞中 SRSF1 的条件性消融导致 iNKT 细胞库大幅减少。iNKT 细胞从第 0 阶段到第 1 阶段的转变基本上被阻断，并且 iNKT2 子集在 SRSF1 缺陷小鼠中显着减少。SRSF1 缺陷导致一系列与 iNKT 细胞发育和 iNKT2 分化密切相关的调节因子的异常表达，包括 Myb、PLZF、Gata3、ICOS 和 CD5。特别是，我们发现 SRSF1 直接结合并调节Myb的 pre-mRNA 选择性剪接并且在 SRSF1 缺陷型 DP 和 iNKT 细胞中，Myb 的短同种型的表达显着降低。引人注目的是，Myb 短同种型的异位表达部分纠正了 SRSF1 消融引起的缺陷。此外，我们证实 SRSF1 缺陷小鼠在 α-GalCer 和 Con A 诱导后表现出对急性肝损伤的抵抗力。因此，我们的研究结果揭示了 SRSF1 在 iNKT 细胞发育和功能分化中作为重要转录后调节因子的先前未知作用，为 iNKT 相关疾病提供了新的临床见解。