# The influence of TC0668 on glycometabolism modulation in Chlamydia muridarum-infected host cells

## TL;DR

The study explores how the Chlamydia muridarum protein TC0668 affects host cell metabolism and enhances infection through the PI3K/AKT pathway.

## Contribution

The study reveals a novel mechanism by which TC0668 modulates host glycometabolism to enhance Chlamydia pathogenicity.

## Key findings

- TC0668 induces a hypermetabolic state in host cells, altering glucose consumption and ATP levels.
- PI3K/AKT pathway activation is crucial for TC0668-induced glycometabolism changes in infected cells.
- Inhibition of PI3K/AKT reduces glucose consumption and ATP levels in HUVECs but not in HeLa cells.

## Abstract

Chlamydia, an obligate intracellular parasite, depends entirely on host cells for energy and biosynthesis while exerting pathogenic effects through its virulence factors. Chlamydia muridarum (Cm), an alternative model strain to Chlamydia trachomatis (Ct), modulates cellular metabolism to enhance its survival and pathogenicity during infection. We found that TC0668, a crucial Cm virulence protein associated with fallopian tube lesions in infected mice, induces a hypermetabolic state in host cells upon Cm stimulation. This results in alterations in glucose consumption, mitochondrial TCA cycle activity, aerobic glycolysis, and intracellular ATP levels. Specifically, infection with the Cm TC0668wt strain in HeLa and HUVEC cells led to the activation of PI3K (p110) and substantial phosphorylation of AKT at S473. This activation was significantly reduced by LY-294002, a potent PI3K/AKT pathway inhibitor, which led to decreased glucose consumption and ATP levels in HUVECs. However, in HeLa cells, inhibition of the pathway primarily affected GLUT1 expression and ATP levels without impacting glucose consumption. These findings underscore the pivotal role of PI3K/AKT signaling in regulating cellular glycometabolism under the influence of the TC0668 protein during Cm infection.

Previous studies have identified that TC0668, as a virulence factor involved in the formation of fallopian tube hydrosalpinx caused by Chlamydia muridarum (Cm), is primarily involved in metabolic processes, cellular processes, and biological regulation, and there are notable differences in PI3K activation and AKT phosphorylation induced by Cm tc0668 single-gene strains. However, the relationship between TC0668’s influence on Cm-regulated glycometabolism and the activation of the PI3K/AKT pathway remains unclear. Our study established a vitro cell infection model of Cm using HeLa cells and HUVEC cells, and employed techniques such as Western blotting to reveal a novel mechanism of TC0668 in enhancing the pathogenicity of Cm by regulating host glycometabolism. The study advances our understanding of intracellular pathogen-host interactions and provides novel therapeutic strategies for Chlamydia infections.