Folia Parasitologica 68:016 (2021) | DOI: 10.14411/fp.2021.016

Toxoplasma gondii ROP17 promotes autophagy via the Bcl-2-Beclin 1 pathway

Min Guo^1,2,4, Jia Sun^1,4, Wen-tao Wang^1,4, Hong-yan Liu^1,3, Yue-hua Liu¹, Ke-ru Qin¹, Jin-rui Hu¹, Xin-yang Li¹, Hong-li Liu¹, Wei Wang¹, Zhao-yang Chen ORCID...^2*, Chun-fang Wang ORCID...^2*, Hai-long Wang ORCID...^1*

¹ School of Basic Medicine, Basic Medical Science Center, Shanxi Medical University, Jinzhong, Shanxi, China;

² Labratory Animal Center, Shanxi Key Laboratory of Experimental Animal Science and Animal Model of Human Disease, Shanxi Medical University, Taiyuan,Shanxi, China;

³ Eugenics and Molecular Medicine Testing Center, Ulanqab Central Hospital, Wulanchabu, Neimenggu, China

⁴ Min Guo, Jia Sun and Wen-tao Wang contributed equally to this work *Address for correspondence: Hai-long Wang, Email: longwty@163.com; Chun-fang Wang, Email: wangchunfang1@163.com; Zhao-yang Chen, Email: ccytycn@163.com; Address: School of Basic Medicine, Shanxi Medical University, No. 55, Wenhua Street, Jinzhong, Shanxi, 030600, China

The apicomplexan Toxoplasma gondii (Nicolle et Manceaux, 1908) secretes a group of serine/threonine kinases from rhoptries, which play vital roles in boosting intracellular infection. Toxoplasma gondii rhoptry organelle protein 17 (ROP17) is one of these important kinase proteins. Nevertheless, its function remains unclear. Here, we showed that ROP17 induced autophagy in vitro and in vivo. The autophagy of small intestine tissues of T. gondii tachyzoite (RH strain)-infected mice was detected by the immunohistochemistry staining of LC3B, Beclin 1 and P62. ROP17 overexpression augmented starvation-induced autophagy in HEK 293T cells as measured by MDC staining, transmission electron microscopy (TEM), fluorescence microscopy and Western blot analysis. Moreover, the interaction of ROP17 and Bcl-2 was confirmed using co-immunoprecipitation analysis, and the data demonstrated that ROP17 had an autophagic role dependent on the Beclin 1-Bcl-2 pathway, which was also revealed in an in vivo model through immunohistochemical staining. Pearson coefficient analysis showed that there existed strong positive correlations between the expression of ROP17 and LC3B, Beclin 1 and phosphorylation of Bcl-2, while strong negative correlations between the expression of ROP17 and p62 and Bcl-2. Collectively, our findings indicate that ROP17 plays a pivotal role in maintaining T. gondii proliferation in host cells via the promotion of autophagy-dependent survival.

Keywords: Toxoplasma, rhoptry organelle protein 17, cellular autophagy, Becn 1, B-cell lymphoma-2

Received: September 1, 2020; Revised: February 26, 2021; Accepted: March 7, 2021; Published online: June 18, 2021  Show citation