PTEN differentially regulates endocytosis, migration, and proliferation in the enteric protozoan parasite Entamoeba histolytica

PLoS Pathog. 2022 May 2;18(5):e1010147. doi: 10.1371/journal.ppat.1010147. eCollection 2022 May.

Abstract

PTEN is a lipid phosphatase that is highly conserved and involved in a broad range of biological processes including cytoskeletal reorganization, endocytosis, signal transduction, and cell migration in all eukaryotes. Although regulation of phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] signaling via PTEN has been well established in model organisms and mammals, it remains elusive in the parasitic protist E. histolytica, which heavily relies on PtdIns phosphate(s)-dependent membrane traffic, migration, and phago- and trogocytosis for its pathogenesis. In this study, we characterized the major PTEN from E. histolytica, EhPTEN1, which shows the highest expression at the transcript level in the trophozoite stage among 6 possible PTENs, to understand the significance of PtdIns(3,4,5)P3 signaling in this parasite. Live imaging of GFP-EhPTEN1 expressing amebic trophozoites showed localization mainly in the cytosol with a higher concentration at pseudopods and the extending edge of the phago- and trogocytic cups. Furthermore, quantitative analysis of phago- and trogocytosis using a confocal image cytometer showed that overexpression of EhPTEN1 caused reduction in trogo- and phagocytosis while transcriptional gene silencing of EhPTEN1 gene caused opposite phenotypes. These data suggest that EhPTEN1 has an inhibitory role in these biological processes. Conversely, EhPTEN1 acts as a positive regulator for fluid-phase and receptor-mediated endocytosis in E. histolytica trophozoites. Moreover, we showed that EhPTEN1 was required for optimal growth and migration of this parasite. Finally, the phosphatase activity of EhPTEN1 towards PtdIns(3,4,5)P3 was demonstrated, suggesting that the biological roles of EhPTEN1 are likely linked to its catalytic function. Taken together, these results indicate that EhPTEN1 differentially regulates multiple cellular activities essential for proliferation and pathogenesis of the organism, via PtdIns(3,4,5)P3 signaling. Elucidation of biological roles of PTEN and PtdIns(3,4,5)P3 signaling at the molecular levels promotes our understanding of the pathogenesis of this parasite.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation
  • Endocytosis
  • Entamoeba histolytica* / metabolism
  • Mammals
  • Parasites*
  • Phagocytosis
  • Phosphatidylinositols / metabolism
  • Trophozoites / metabolism

Substances

  • Phosphatidylinositols

Grants and funding

This work was supported by Core-to-Core Program, (JPJSCCB20190010) from the Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (B) (JP18H02650 and JP21H02723 to TN) from the Japan Society for the Promotion of Science, Grant for Science and Technology Research Partnership for Sustainable Development (SATREPS) from AMED and Japan International Cooperation Agency (JICA) (JP20jm0110022) to TN, Grant for research on emerging and re-emerging infectious diseases from Japan Agency for Medical Research and Development (AMED, JP20fk0108138 to TN) and (AMED, JP20fk0108139 to KNT), Grants-in-Aid for Scientific Research (B) and Scientific Research on Innovative Areas (JP19H03463 and JP20H05353 to KNT) from Ministry of Education, Culture, Sports, Science and Technology (MEXT) or Japan Society for Promotion of Sciences (JSPS), Grant-in-Aid for Research Activity start-up (JP20K22758 to NW), Sasagawa Scientific Research Grant from The Japan Science Society (2020-4044 to NW), and Grant-in-Aid for Young Scientists from Wakate (JP21K15426 to NW). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.