College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China.
Section of Anatomy and Histology, Department of Basic Sciences, College of Veterinary and Animal Sciences (CVAS), Jhang, Punjab, Pakistan.
Arch Immunol Ther Exp (Warsz). 2021 Apr 15;69(1):11. doi: 10.1007/s00005-021-00611-y.
Visfatin is a multifunctional protein involved in inflammatory immune stress. The aim of current study was to explore the role of visfatin in lipopolysaccharide (LPS)-induced intestinal mucosal inflammation and to confirm its cellular effect in inflammatory immune response through silencing of Toll-like receptors (TLRs). We divided Kunming mice into three groups: Saline group, LPS group, and LPS + visfatin group and performed hematoxylin and eosin staining, immunohistochemistry, quantitative polymerase chain reaction, Western blot, enzyme linked immunosorbent assay and RNA-seq analysis. Pretreatment of visfatin improves LPS-stimulated reduction of tight junction protein 1 (ZO-1) and secretory immunoglobulin A, inhibits overexpression of Claudin-1 and vascular endothelial growth factor, and reduces intestinal mucosal damage and inflammation. RNA-seq analysis of cellular transcriptomes indicated that visfatin is involved in down-regulation of mRNA level of TLR4 as well as attenuation of protein levels of TLR8 and nucleotide-binding oligomerization domain-containing protein 2, revealing that visfatin could reduce intestinal mucosal inflammation through TLR signaling pathway in mice ileum. In RAW264.7 cells, the genes silencing of Toll/IL-1R family, such as TLR4, TLR2, and IL-1R1, was accompanied by decreased expressions of inflammatory factors (TNF-α, IL-1β, IL-6 and MCP-1) along with lower cellular visfatin levels. Hence, visfatin maintains the intestinal mucosal barrier structure and attenuates the intestinal mucosal inflammation through the TLR signaling pathway. Likewise, the Toll/IL-1R family regulates the release of visfatin, which can participate in the inflammatory reaction through the regulation of inflammatory factors.
内脏脂肪素是一种多功能蛋白，参与炎症免疫应激。本研究旨在探讨内脏脂肪素在脂多糖（LPS）诱导的肠黏膜炎症中的作用，并通过沉默 Toll 样受体（TLRs）来证实其在炎症免疫反应中的细胞效应。我们将昆明小鼠分为三组：生理盐水组、LPS 组和 LPS+内脏脂肪素组，并进行苏木精和伊红染色、免疫组织化学、定量聚合酶链反应、Western blot、酶联免疫吸附试验和 RNA-seq 分析。内脏脂肪素预处理可改善 LPS 刺激引起的紧密连接蛋白 1（ZO-1）和分泌型免疫球蛋白 A 的减少，抑制 Claudin-1 和血管内皮生长因子的过度表达，减少肠黏膜损伤和炎症。细胞转录组的 RNA-seq 分析表明，内脏脂肪素参与下调 TLR4 的 mRNA 水平，并减弱 TLR8 和核苷酸结合寡聚化结构域包含蛋白 2 的蛋白水平，表明内脏脂肪素可通过小鼠回肠中的 TLR 信号通路减轻肠黏膜炎症。在 RAW264.7 细胞中，Toll/IL-1R 家族（如 TLR4、TLR2 和 IL-1R1）的基因沉默伴随着炎症因子（TNF-α、IL-1β、IL-6 和 MCP-1）的表达降低以及细胞内脏脂肪素水平降低。因此，内脏脂肪素通过 TLR 信号通路维持肠黏膜屏障结构并减轻肠黏膜炎症。同样，Toll/IL-1R 家族调节内脏脂肪素的释放，通过调节炎症因子，内脏脂肪素可以参与炎症反应。
