The Putative TCP-1 Chaperonin Is an Important Player Involved in Sialic Acid-Dependent Host Cell Invasion by Toxoplasma gondii

Na Yang; Mengen Xing; Yingying Ding; Dawei Wang; Xiaogai Guo; Xiaoyu Sang; Jiaqi Li; Chenghuan Li; Yanhu Wang; Ying Feng; Ran Chen; Xinyi Wang; Ning Jiang; Qijun Chen

doi:10.3389/fmicb.2020.00258

The Putative TCP-1 Chaperonin Is an Important Player Involved in Sialic Acid-Dependent Host Cell Invasion by Toxoplasma gondii

Front Microbiol. 2020 Feb 21:11:258. doi: 10.3389/fmicb.2020.00258. eCollection 2020.

Authors

Na Yang¹, Mengen Xing^{1

2}, Yingying Ding¹, Dawei Wang^{1

2

3}, Xiaogai Guo¹, Xiaoyu Sang¹, Jiaqi Li¹, Chenghuan Li¹, Yanhu Wang¹, Ying Feng¹, Ran Chen^{1

2}, Xinyi Wang⁴, Ning Jiang^{1

2}, Qijun Chen^{1

2}

Affiliations

¹ Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China.
² The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, Shenyang, China.
³ College of Food Science and Engineering, Shenyang Agricultural University, Shenyang, China.
⁴ College of Basic Sciences, Shenyang Agricultural University, Shenyang, China.

Abstract

Host cell invasion by Toxoplasma gondii is crucial for the survival and proliferation of parasite. The process of T. gondii tachyzoite invasion requires interaction between parasite proteins and receptors on the surface of host cells. Sialic acid is one of the important receptors for host cell invasion by T. gondii. However, the parasite-derived proteins interacting with sialic acid have not been well characterized. In this study, a novel protein named putative TCP-1 chaperonin (TGME49_318410) in T. gondii (TgTCP-1) was targeted and characterized. TgTCP-1 protein colocalized with MIC3 protein, which could be secreted from T. gondii tachyzoites, and this protein showed a specific binding activity to sialic acid, and DC and Vero cells in vitro. The binding of TgTCP-1 protein to DC and Vero cells were inhibited by either pre-incubation with free sialic acid or neuraminidase treatment of the cells. Moreover, a significant reduction of T. gondii invasion in Vero cells was observed after pre-incubation of the cells with recombinant TgTCP-1 protein. These results illustrated that TgTCP-1 is an important molecule involved in sialic acid-dependent host cell invasion by T. gondii.

Keywords: TgTCP-1; Toxoplasma gondii; host cell; invasion; sialic acid receptor.