Inhibitory Effects of Inonotus obliquus Polysaccharide on Inflammatory Response in Toxoplasma gondii- Infected RAW264.7 Macrophages

Kexin Yan; Hongyuan Zhou; Meng Wang; Haitao Li; Rui Sang; Bingjie Ge; Xin Zhao; Chunting Li; Wei Wang; Xuemei Zhang

doi:10.1155/2021/2245496

Inhibitory Effects of Inonotus obliquus Polysaccharide on Inflammatory Response in Toxoplasma gondii- Infected RAW264.7 Macrophages

Evid Based Complement Alternat Med. 2021 Dec 29:2021:2245496. doi: 10.1155/2021/2245496. eCollection 2021.

Authors

Kexin Yan¹, Hongyuan Zhou¹, Meng Wang¹, Haitao Li^{1

2}, Rui Sang¹, Bingjie Ge¹, Xin Zhao¹, Chunting Li¹, Wei Wang¹, Xuemei Zhang^{1

3}

Affiliations

¹ Agricultural College of Yanbian University, Gongyuan Street, Yanji, Jilin 133002, China.
² Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Juye Street, Changchun, Jilin 132109, China.
³ Engineering Research Center of North-East Cold Region Beef Cattle Science & Technology Innovation, Ministry of Education, Yanbian University, Gongyuan Street, Yanji, Jilin 133002, China.

Abstract

Our previous reports have shown that Inonotus obliquus polysaccharide (IOP) has protective effects against Toxoplasma gondii (T. gondii) infection in vivo. The aim of the present research is to explore the in vitro anti-inflammatory effects of IOP and its mechanism in RAW264.7 macrophages infected by T. gondii. In this study, it is indicated that IOP decreased the excessive secretion of inflammatory cytokines tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-4, and IL-6 in T. gondii-infected RAW264.7 macrophages. IOP effectively suppressed the mRNA expression of these cytokines and chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α). Moreover, IOP inhibited the phosphorylation of inhibitor kappa B kinase α/β (IKKα/β), inhibitor κBα (IκBα), p65 in nuclear factor-kappa B (NF-κB) signaling pathway and p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase 1/2 (ERK1/2) in mitogen-activated protein kinases (MAPKs) signaling pathway. Meantime, IOP prevented NF-κB p65 and c-Jun translocation from the cytoplasm to the nucleus. Further, IOP downregulated the protein expression of toll-like receptor 2 (TLR2) and TLR4 in T. gondii-infected RAW264.7 macrophages. The above results suggest that IOP can inhibit the inflammatory response infected with T. gondii via regulating TLR2/TLR4-NF-κB/MAPKs pathways and exerting its anti-T. gondii role in vitro.