PIP2 regulating calcium signal modulates actin cytoskeleton-dependent cytoadherence and cytolytic capacity in the protozoan parasite Trichomonas vaginalis

PLoS Pathog. 2023 Dec 18;19(12):e1011891. doi: 10.1371/journal.ppat.1011891. eCollection 2023 Dec.

Abstract

Trichomonas vaginalis is a prevalent causative agent that causes trichomoniasis leading to uropathogenic inflammation in the host. The crucial role of the actin cytoskeleton in T. vaginalis cytoadherence has been established but the associated signaling has not been fully elucidated. The present study revealed that the T. vaginalis second messenger PIP2 is located in the recurrent flagellum of the less adherent isolate and is more abundant around the cell membrane of the adherent isolates. The T. vaginalis phosphatidylinositol-4-phosphate 5-kinase (TvPI4P5K) with conserved activity phosphorylating PI(4)P to PI(4, 5)P2 was highly expressed in the adherent isolate and partially colocalized with PIP2 on the plasma membrane but with discrete punctate signals in the cytoplasm. Plasma membrane PIP2 degradation by phospholipase C (PLC)-dependent pathway concomitant with increasing intracellular calcium during flagellate-amoeboid morphogenesis. This could be inhibited by Edelfosine or BAPTA simultaneously repressing parasite actin assembly, morphogenesis, and cytoadherence with inhibitory effects similar to the iron-depleted parasite, supporting the significance of PIP2 and iron in T. vaginalis colonization. Intriguingly, iron is required for the optimal expression and cell membrane trafficking of TvPI4P5K for in situ PIP2 production, which was diminished in the iron-depleted parasites. TvPI4P5K-mediated PIP2 signaling may coordinate with iron to modulate T. vaginalis contact-dependent cytolysis to influence host cell viability. These observations provide novel insights into T. vaginalis cytopathogenesis during the host-parasite interaction.

MeSH terms

  • Actin Cytoskeleton
  • Animals
  • Calcium / metabolism
  • Iron / metabolism
  • Parasites*
  • Trichomonas vaginalis*

Substances

  • Calcium
  • Iron

Grants and funding

This study was supported by grants from the National Science and Technology Council (110-2320-B-002-076- and 112-2320-B-002-060-, Grant Recipient: Dr. Hong-Ming Hsu) and National Taiwan University (NTU-JP-112L7226, Grant Recipient: Dr. Hong-Ming Hsu). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.