Polymorphic Membrane Protein 17G of Chlamydia psittaci Mediated the Binding and Invasion of Bacteria to Host Cells by Interacting and Activating EGFR of the Host.

Xiaohui Li,Zonghui Zuo,Cheng He,Johannes H Hegemann,Yihui Wang

doi:10.3389/fimmu.2021.818487

Abstract

Chlamydia psittaci (C. psittaci) is an obligate intracellular, gram-negative bacterium, and mainly causes systemic disease in psittacine birds, domestic poultry, and wild fowl. The pathogen is threating to human beings due to closely contacted to employees in poultry industry. The polymorphic membrane proteins (Pmps) enriched in C. psittaci includes six subtypes (A, B/C, D, E/F, G/I and H). Compared to that of the 1 pmpG gene in Chlamydia trachomatis (C. trachomatis), the diverse pmpG gene-coding proteins of C. psittaci remain elusive. In the present study, polymorphic membrane protein 17G (Pmp17G) of C. psittaci mediated adhesion to different host cells. More importantly, expression of Pmp17G in C. trachomatis upregulated infections to host cells. Afterwards, crosstalk between Pmp17G and EGFR was screened and identified by MALDI-MS and Co-IP. Subsequently, EGFR overexpression in CHO-K1 cells and EGFR knockout in HeLa 229 cells were assessed to determine whether Pmp17G directly correlated with EGFR during Chlamydial adhesion. Finally, the EGFR phosphorylation was recognized by Grb2, triggering chlamydial invasion. Based on above evidence, Pmp17G possesses adhesive property that serves as an adhesin and activate intracellular bacterial internalization by recognizing EGFR during C. psittaci infection

Highlights

Chlamydia psittaci (C. psittaci) is an important zoonotic agent with a wide host spectrum [1]
Strong polymorphic membrane protein 17G (Pmp17G) adhesion was found to HeLa 229 cells, and secondary higher attaching capability was observed in Vero cells than DF-1 cells did
Early adhesion was observed at 15 min, and an increasing attachment was correlated with prolonged incubation and the strongest signal was detected at 120 min, while secondary adhesion occurred at 60 min in Vero cells and 120 min in DF-1 cells, respectively (Figure 1A)

Summary

Introduction

Chlamydia psittaci (C. psittaci) is an important zoonotic agent with a wide host spectrum [1]. It causes systemic infection, especially in birds, which leads to profound economic losses in poultry annually [2]. For reporting cases of C. psittaci infection, a national surveillance program in the United States (U.S.) has been operational since 1998. No surveillance or case reporting system has been implemented for identifying human chlamydiosis in China. Case of human psittacosis has increased gradually, and 15 workers were reported to be infected in a U.S poultry slaughterhouse. Human psittacosis has increased gradually in China due to implementation of generation genomic sequencing. The mechanism by which the target hosts is infected and tissue tropism exhibited by C. psittaci upon infection remain unknown

Methods

Results

Conclusion