The cellular ceramide transport protein CERT promotesChlamydia psittaciinfection and controls bacterial sphingolipid uptake

Abstract

Chlamydiaceae are bacterial pathogens that cause diverse diseases in humans and animals. Despite their broad host and tissue tropism, all Chlamydia species share an obligate intracellular cycle of development and have evolved sophisticated mechanisms to interact with their eukaryotic host cells. Here, we have analysed interactions of the zoonotic pathogen Chlamydia psittaci with a human epithelial cell line. We found that C. psittaci recruits the ceramide transport protein (CERT) to its inclusion. Chemical inhibition and CRISPR/Cas9-mediated knockout of CERT showed that CERT is a crucial factor for C. psittaci infections thereby affecting different stages of the infection including inclusion growth and infectious progeny formation. Interestingly, the uptake of fluorescently labelled sphingolipids in bacteria inside the inclusion was accelerated in CERT-knockout cells indicating that C. psittaci can exploit CERT-independent sphingolipid uptake pathways. Moreover, the CERT-specific inhibitor HPA-12 strongly diminished sphingolipid transport to inclusions of infected CERT-knockout cells, suggesting that other HPA-12-sensitive factors are involved in sphingolipid trafficking to C. psittaci. Further analysis is required to decipher these interactions and to understand their contributions to bacterial development, host range, tissue tropism, and disease outcome.

Chlamydia trachomatis‐infected human cells convert ceramide to sphingomyelin without sphingomyelin synthases 1 and 2

“…Previous studies have shown that sphingolipids derived from host cells are required for the proliferation of C. trachomatis . In addition, CERT is required for the proliferation of several Chlamydia species ( C. trachomatis , C. muridarum , and C. psittaci ). CERT is recruited to the inclusion membrane by binding to the inclusion membrane protein IncD , which is encoded by the C. trachomatis genome.…”

A Comprehensive Review on the Manipulation of the Sphingolipid Pathway by Pathogenic Bacteria

“…In contrast to M. tuberculosis, Chlamydia trachomatis , a Gram-negative obligate intracellular pathogen responsible for trachoma and sexually transmitted diseases, develops, after binding and entry into target cells, a membrane-bound vacuole, termed inclusion that minimizes the interaction with immune defenses and other host-derived molecules. It has been shown that the inclusion membrane contains sphingomyelin (Hackstadt et al, 1996) and that C. trochomatis and Chlamydia psittaci actively redirect sphingomyelin biosynthesis at the inclusion membrane by recruitment of sphingomyelin synthases, a step strictly necessary for inclusion growth and stability (Elwell et al, 2011; Koch-Edelmann et al, 2017).…”

Development of a Plasmid Shuttle Vector System for Genetic Manipulation of Chlamydia psittaci

“…Reinhold et al established a bovine respiratory model of acute C. psittaci infection using strain 02DC15 ( 27 ). Koch-Edelmann et al demonstrated the importance of lipid metabolism in C. psittaci 02DC15 infection ( 25 ). Dutow et al elucidated the role of effector of the complement (C3a) in C. psittaci 02DC15 infection ( 22 ).…”

“…S8), we were able to show that all of the genes present in C. psittaci 6BC are encountered in C. psittaci 02DC15 as well, thus indicating their genetic equivalence. Due to the genome similarity between C. psittaci 6BC and C. psittaci 02DC15, C. psittaci 02DC15 is widely used for a number of immunological and cell biological studies, as well as animal infection trials (22)(23)(24)(25)(26)(27)(28). Reinhold et al established a bovine respiratory model of acute C. psittaci infection using strain 02DC15 (27).…”