Related Experiment Video

Updated: Mar 8, 2026

In-vitro Reconstitution of Bacterial Ubiquitination and VCP/p97-mediated Elimination
07:58

In-vitro Reconstitution of Bacterial Ubiquitination and VCP/p97-mediated Elimination

Published on: January 2, 2026

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Intracellular fate of Ureaplasma parvum entrapped by host cellular autophagy

Fumiko Nishiumi1, Michinaga Ogawa2, Yukiko Nakura1

  • 1Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan.

Microbiologyopen
|January 16, 2017
PubMed

Insights

Ureaplasma parvum, a bacterium linked to preterm birth, invades host cells and uses cellular compartments to evade immune detection. This survival strategy involves exosomes, highlighting a novel mechanism for bacterial persistence.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Genital mycoplasmas, including Ureaplasma spp., are small pathogenic bacteria implicated in preterm birth.
  • Understanding Ureaplasma parvum's interaction with host cells is crucial for addressing associated health issues.

Purpose of the Study:

  • To investigate the intracellular survival mechanisms of Ureaplasma parvum within host cells.
  • To explore the role of host cellular compartments and exosomes in Ureaplasma spp. evasion of the immune system.

Main Methods:

  • Electron microscopy to observe U. parvum morphology.
  • Cell culture experiments using HeLa cells and atg7-/- MEF cells to track bacterial internalization and intracellular trafficking.
  • Immunofluorescence labeling for endosomal and autophagy markers (EEA1, Rab7, LAMP-1, LC3, Rab11).
  • Exosome purification and analysis from infected cell culture medium.

Main Results:

  • Ureaplasma parvum was internalized into HeLa cells via clathrin-mediated endocytosis and survived for at least 14 days, primarily around the perinuclear region.
  • Intracellular U. parvum trafficked through endosomes and was targeted by autophagy (LC3), although autophagy was insufficient for complete elimination in atg7-/- cells.
  • U. parvum was found within exosomes released from infected cells, along with bacterial and host cellular proteins.

Conclusions:

  • Ureaplasma spp. employ host cellular membrane compartments, including endosomes and exosomes, to evade the host immune system.
  • The internalization and intracellular survival of U. parvum suggest a complex interaction aimed at persistence within the host.
  • Exosome-mediated dissemination or protection represents a potential novel mechanism for Ureaplasma spp. pathogenesis.
Keywords:
Ureaplasma sppautophagyendocytosisexosomegalectin

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