Chlamydial YAP activation in host endocervical epithelial cells mediates pro-fibrotic paracrine stimulation of fibroblasts

Liam Caven, Rey Carabeo

Research output: Contribution to journalArticlepeer-review


Infection of the female genital tract by Chlamydia trachomatis can produce severe fibrotic sequelae, including tubal factor infertility and ectopic pregnancy. While infection demonstrably mediates a pro-fibrotic response in host cells, it remains unclear if intrinsic properties of the upper genital tract exacerbate chlamydial fibrosis. The relatively sterile environment of the upper genital tract is primed for a pro-inflammatory response to infection, potentially enhancing fibrosis; however, subclinical C. trachomatis infections still develop fibrosis-related sequelae. Here, we compare infection-associated and steady-state gene expression of primary human cervical and vaginal epithelial cells. In the former, we observe enhanced baseline expression and infection-mediated induction of fibrosis-associated signal factors (e.g., TGFA, IL6, IL8, and IL20), implying predisposition to Chlamydia-associated pro-fibrotic signaling. Transcription factor enrichment analysis identified regulatory targets of YAP, a transcriptional cofactor induced by infection of cervical epithelial cells, but not vaginal epithelial cells. YAP target genes induced by infection include secreted fibroblast-activating signal factors; therefore, we developed an in vitro model involving coculture of infected endocervical epithelial cells with uninfected fibroblasts. Coculture enhanced fibroblast expression of type I collagen, as well as prompting reproducible (albeit statistically insignificant) induction of α-smooth muscle actin. Fibroblast collagen induction was sensitive to siRNA-mediated YAP knockdown in infected epithelial cells, implicating chlamydial YAP activation in this effect. Collectively, our results present a novel mechanism of fibrosis initiated by Chlamydia, wherein infection-mediated induction of host YAP facilitates pro-fibrotic intercellular communication. Chlamydial YAP activation in cervical epithelial cells is thus a determinant of this tissue’s susceptibility to fibrosis.

Original languageEnglish (US)
Issue number6
StatePublished - Dec 2023


  • Chlamydia trachomatis
  • YAP
  • fibrosis
  • host-pathogen interaction

ASJC Scopus subject areas

  • Microbiology
  • Physiology
  • Biochemistry
  • Ecology, Evolution, Behavior and Systematics
  • Modeling and Simulation
  • Molecular Biology
  • Genetics
  • Computer Science Applications


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