研究人员发现由微生物群在肠上皮细胞中诱导的视黄醇结合蛋白-血清淀粉样蛋白A(SAA)将视黄醇递送到骨髓细胞。研究人员发现低密度脂蛋白(LDL)受体相关蛋白1(LRP1) 是 SAA的受体，可内吞SAA-视黄醇复合物并促进产生视黄酸(RA)使肠髓细胞获得视黄醇。因此，SAA和LRP1对维生素A依赖性免疫至关重要，包括B和T细胞归巢至肠道以及免疫球蛋白A的产生。该研究结果揭示了维生素A促进肠道免疫的关键机制。
据介绍，维生素A及其衍生物视黄醇对于肠道适应性免疫的形成至关重要。产生RA的骨髓细胞在这一过程中发挥核心作用，但尚不清楚骨髓细胞如何获得视黄醇以转化为RA。
附：英文原文
Title: Serum amyloid A delivers retinol to intestinal myeloid cells to promote adaptive immunity
Author: Ye-Ji Bang, Zehan Hu, Yun Li, Sureka Gattu, Kelly A. Ruhn, Prithvi Raj, Joachim Herz, Lora V. Hooper
Issue&Volume: 2021-09-17
Abstract: Vitamin A and its derivative retinol are essential for the development of intestinal adaptive immunity. Retinoic acid (RA)–producing myeloid cells are central to this process, but how myeloid cells acquire retinol for conversion to RA is unknown. Here, we show that serum amyloid A (SAA) proteins—retinol-binding proteins induced in intestinal epithelial cells by the microbiota—deliver retinol to myeloid cells. We identify low-density lipoprotein (LDL) receptor–related protein 1 (LRP1) as an SAA receptor that endocytoses SAA-retinol complexes and promotes retinol acquisition by RA-producing intestinal myeloid cells. Consequently, SAA and LRP1 are essential for vitamin A–dependent immunity, including B and T cell homing to the intestine and immunoglobulin A production. Our findings identify a key mechanism by which vitamin A promotes intestinal immunity.
DOI: abf9232
Source: https://www.science.org/doi/10.1126/science.abf9232