SMB Faculty Profiles

John Alderete

John Alderete

Room: BLS 437
Office Phone: 509-335-8125
Room: BLS 440
Lab Phone: 509-335-8042


Research & Interests

Trichomonas vaginalis, the number one, non-viral sexually transmitted organism, is the focus of our research program. The study of parasite and host cell-tissue interactions is focused on the identification of surface proteins that contribute to infection and disease pathogenesis.

We have studied several important properties of the biology of the parasite and the host-parasite interaction. These include antigenic diversity, cytoadherence, immune evasion, iron acquisition, and the dsRNA virus infection. The highly evolved and complex nature of the interrelationship between host and parasite is evidenced by the dynamics of the protein-antigen phenotypic variations and the various important protein repertoires, which have been defined. The phenotypic variation of trichomonad protein repertoires can either be coordinated, such as for the immunogens and adhesins, or be independent of one another, as seen for the proteinases. DNA sequence and the other data have been used to determine that an important phenotypically varying immunogen (P270) contains only one immunodominant epitope repeated many times, and the number of repeats varies among clinical isolates. Among most isolate trichomonads, this tandemly-repeated sequence was further found to comprise one-half of the total protein size, illustrating the complexity of the immunogen in terms of silent versus active antibody-generating domains.

The fact that trichomonads survive during phenotypic variation (without surface expression of major immunogens) does not suggest an absence of an important biofunctionality for these molecules. Biofunctional proteins, such as the epithelial cell- and erythrocyte-binding adhesins, also undergo phenotypic variation that is modulated by iron. More recently, we obtained evidence that the phenotypically varying protein plays a role in lipoprotein uptake, an important property given that trichomonads cannot synthesize lipids.

The studies on the immune evasion strategies of T. vaginalis are important for our understanding of the mechanisms of parasite survival during a host antibody response, especially when antibody readily kills the parasite in a complement-independent manner. This information may also lead to interference strategies apart from the development of vaccines to trichomonad proteins, like the adhesins. The future for pharmacologic targeting appears possible with the recent, exciting observation that proteinase activity, apart from degrading immunoglobulins and complement, is necessary for initial and sustained host parasitism.

The importance of a holistic, multidisciplinary approach to dissecting and understanding the complex host-parasite interaction is evidenced by several recent findings. Iron both up- and down-regulates transcription of genes, including adhesins and immunogens. Further, iron modulates compartmentalization and surface expression of the adhesins. Importantly, the adhesins have sequence identity to hydrogenosome metabolic enzymes, thereby invoking molecular mimicry, gene sharing, and functional diversity as important features for surface proteins of this parasite. Finally, the double-stranded RNA virus and satellite dsRNAs infecting T. vaginalis influence expression of many parasite proteins and directly correlate with the property of phenotypic variation.

Several recent new discoveries are the following: 1) There is a relationship between polyamine metabolism and the properties of cytoadherence and cytotoxicity. There is a direct relationship between polyamine depletion and enhanced adherence coupled with complete absence of host cell killing. Moreover, polyamine depletion down-regulates transcription of the cysteine proteinase known to be involved in cytotoxicity. 2) We have established an efficient transfection system that has permitted us to inhibit expression of trichomonad genes, thereby establishing a genetic approach to confirm the function of the adhesins and other virulence genes. 3) We have performed heterologous expression of functional T. vaginalis virulence genes in the bovine trichomonad Tritrichomonas foetus, and this opens exciting new approaches for examining virulence factors in a related organism. 4) We have demonstrated the up-regulation of gene expression in vaginal epithelial cells and in T. vaginalis that result immediately upon contact, showing that there are signaling events taking place in both parasites and host cells. 5) Adhesins and other trichomonad ligands for binding host molecules are among numerous metabolic enzymes of the secretome that become associated with the parasite surface for expression of function, properties that are also found among other microbial pathogens. 6) Finally, a noteworthy new finding is the relationship between seropositivity of men to T. vaginalis and prostate cancer, a finding that will establish a new paradigm for a microbial pathogen—this STD agent—as a causative agent for carcinogenesis.

Trichomonads have an ellipsoid morphology when grown in batch culture and when adherent to the HeLa epithelial cells (a transformed cell line). Note the flagella and undulating membranes are on the side opposite adherent to the epithelial cells.
This is a cross-section electron photomicrograph showing the parasite (dark cell) intimacy with the vaginal epithelial cell (light cell). The vaginal epithelial cell is the tropic cell during colonization of the vaginal epithelium following infection. The membrane-membrane, parasite-host cell interaction is indicative of very specific ligand-receptor binding reactions.
 organisms arriving and attaching to the epithelial cell
After attachment of a single parasite to the host cell, there appears to be signaling by the parasite to attract other parasites to the parasitized cell. This leads to numerous organisms arriving and attaching to the epithelial cell.
adherence to vaginal epithelial cells
Unlike attachment to HeLa epithelial cells, adherence to vaginal epithelial cells leads to dramatic morphologic transformation from ellipsoid to amoeboid with many filopodia and pseudopodia (the membrane extensions). The fact that this change in morphology occurs only with vaginal epithelial cells is indicative of specific signaling by the host cell to the parasite.
Select Publications
  • Chen, Y-C., Y.-L. Huang, E.A. Platz, L. Zheng, J.R. Stark, J.F. Alderete, E. Giovannucci, and S. Sutcliffe. (2011) Toll-like receptor 4 polymorphisms modify the assoviation between Trichomonas vaginalis serostatus and prostate cancer risk. Cancer Causes & Control PMID: PMCID:
  • Hernandez-Romano, P., R. Arroyo, J.F. Alderete, R. Hernandez, and I. Lopez-Villasenor. (2010) Identification and characterization of a surface-associated subtilisin-like serine protease in Trichomonas vaginalis. Parasitology 137:1621-1635 PMID: 20602853 PMCID:
  • Nogueira, S.V., M.L. Rodrigues, V. Mundodi, E.A. Abi-Chacra, M.S. Winters, J.F. Alderete, and C.M. de Almeida Soares. (2010) Paracoccidioides brasiliensis enolase is a surface protein that binds plasminogen and mediates interaction of yeast forms with host cells. Infect. Immun. 78:4040-4050 PMID: 20605975 PMCID:
  • Stark JR, Judson G, Alderete JF, Mundodi V, Kucknoor AS, Giovannucci EL, Platz EA, Sutcliffe S, Fall K, Kurth T, Ma J, Stampfer MJ, Mucci LA. J (2009) Prospective study of Trichomonas vaginalis infection and prostate cancer incidence and mortality: Physicians' Health Study. Natl Cancer Inst. 101(20):1406-11 PMID: 19741211 PMCID:
  • Sutcliffe S, Kawachi I, Alderete JF, Gaydos CA, Jacobson LP, Jenkins FJ, Viscidi RP, Zenilman JM, Platz EA. (2009) Correlates of sexually transmitted infection histories in a cohort of American male health professionals. Cancer Causes Control 20(9):1623-34 PMID: 19452169 PMCID:
  • Lama A, Kucknoor A, Mundodi V, Alderete JF. (2009) Glyceraldehyde-3-phosphate dehydrogenase is a surface-associated, fibronectin-binding protein of Trichomonas vaginalis. Infect Immun 77(7):2703-11 PMID: 19380472 PMCID:
  • Kucknoor AS, Mundodi V, Alderete J. (2009) Genetic identity and differential gene expression between Trichomonas vaginalis and Trichomonas tenax. BMC Microbiol. 9:58 PMID: 19296850 PMCID:
  • Torres-Machorro AL, Hernández R, Alderete JF, López-Villaseñor I. (2009) Comparative analyses among the Trichomonas vaginalis, Trichomonas tenax, and Tritrichomonas foetus 5S ribosomal RNA genes. Curr Genet. 55(2):199-210 PMID: 19290527 PMCID:
  • utcliffe S, Alderete JF, Till C, Goodman PJ, Hsing AW, Zenilman JM, De Marzo AM, Platz EA. (2009) Trichomonosis and subsequent risk of prostate cancer in the Prostate Cancer Prevention Trial. Int J Cancer 124(9):2082-7 PMID: 19117055 PMCID:
  • Gerhold RW, Allison AB, Sellers H, Linnemann E, Chang TH, Alderete JF. (2009) Examination for double-stranded RNA viruses in Trichomonas gallinae and identification of a novel sequence of a Trichomonas vaginalis virus. Parasitol Res. 105(3):775-9. PMID: 19452169 PMCID:
  • Alvarez-Sánchez ME, Carvajal-Gamez BI, Solano-González E, Martínez-Benitez M, Garcia AF, Alderete JF, Arroyo R. (2008) Polyamine depletion down-regulates expression of the Trichomonas vaginalis cytotoxic CP65, a 65-kDa cysteine proteinase involved in cellular damage. Int J Biochem Cell Biol 40(11):2442-51 PMID: 18586550 PMCID:
  • Mundodi V, Kucknoor AS, Alderete JF. (2008) Immunogenic and plasminogen-binding surface-associated alpha-enolase of Trichomonas vaginalis. Infect Immun 76(2):523-31 PMID: 18070902 PMCID:
  • Mazet M, Diogon M, Alderete JF, Vivarès CP, Delbac F. (2008) First molecular characterisation of hydrogenosomes in the protozoan parasite Histomonas meleagridis. Int J Parasitol. 38(2):177-90. PMID: 17697679 PMCID:
  • Garcia AF, Alderete J. (2007) Characterization of the Trichomonas vaginalis surface-associated AP65 and binding domain interacting with trichomonads and host cells. BMC Microbiol 7:116. PMID: 18158858 PMCID:
  • Mundodi V, Kucknoor AS, Alderete JF. (2007) Antisense RNA decreases AP33 gene expression and cytoadherence by T. vaginalis. BMC Microbiol. 7:64. PMID: 17608941 PMCID:
  • Kucknoor AS, Mundodi V, Alderete JF. (2007) The proteins secreted by Trichomonas vaginalis and vaginal epithelial cell response to secreted and episomally expressed AP65. Cell Microbiol. 9(11):2586-97 PMID: 17590165 PMCID:
  • Kang, J.H., H.O. Song, J.S. Ryu, M.H. Shin, J.M. Kim, Y.S. Cho, J.F. Alderete, M.H. Ahn, and D.Y. Min. (2006) Trichomonas vaginalis promotes apoptosis of human neutrophils by activating caspase-3 and reducing Mcl-1 expression. Parasite Immunol 28:439-446. PMID: PMCID:
  • Sutcliffe, S., E. Giovannucci, J.F. Alderete, T.-H. Chang, C.A. Gaydos, J.M. Zenilman, A.M. De Marzo, W.C. Willett, and E.A. Platz. (2006) Plasma antibodies against Trichomonas vaginalis and subsequent risk of prostate cancer. Cancer, Epidemiol. Biomarkers Prev. 15:939-945. PMID: PMCID:
  • Mundodi, V., A.S. Kucknoor, and J.F. Alderete. (2006) A novel surface protein of Trichomonas vaginalis is regulated independently by low iron and contact with vaginal epithelial cells. BMC Microbiol. 6:6 PMID: PMCID:
  • da Costa, R.F., W. de Souza, M. Benchimol, J.F. Alderete, and J.A. Morgado-Diaz. (2005) Trichomonas vaginalis perturbs the junctional complex in epithelial cells. Cell Res. 15:704-716. PMID: PMCID:
  • Kucknoor, A., V. Mundodi, and J.F. Alderete. (2005) Adherence to human vaginal epithelial cells signals for increased expression of Trichomonas vaginalis genes. Infect. Immun. 73:6472-6478. PMID: PMCID:
  • Kucknoor, A., V. Mundodi, and J.F. Alderete. (2005) Trichomonas vaginalis adherence mediates differential gene expression in human vaginal epithelial cells. Cell Microbiol. 7:887-897. PMID: PMCID:
  • Kucknoor, A., V. Mundodi, and J.F. Alderete. (2005) Heterologous expression in Tritrichomonas foetus of Functional Trichomonas vaginalis AP65 adhesin. BMC Mol. Biol. 6:5. PMID: PMCID:
  • Tasca, T., C.D. Bonan, G.A. DeCarli, J.J. Freitas Sarkis, and J.F. Alderete. (2005) Heterogeneity in extracellular nucleotide hydrolysis among clinical isolates of Trichomonas vaginalis. Parasitol. 131:71-78. PMID: PMCID:
  • Garcia, A., M. Benchimol, and J.F. Alderete. (2005) Trichomonas vaginalis polyamine metabolism is linked to host cell adherence and cytotoxicity. Infect. Immun. 73:2602-2610. PMID: PMCID:
  • Alderete, J.F., J. Nguyen, V. Mundodi, and M.W. Lehker. (2004) Heme-iron increases levels of AP65-mediated adherence by Trichomonas vaginalis. Microbial Pathogenesis. 36:263-271. PMID: PMCID:
  • Mundodi, V., A.S. Kucknoor, D.J. Klumpp, and J.F. Alderete. (2004) Silencing the ap65 gene reduces adherence to vaginal epithelial cells by Trichomonas vaginalis. Mol. Microbiol. 53:1099-1108. PMID: PMCID:
  • Lehker, M.W., M. Benchimol, and J.F. Alderete. (2004) Assigning function to putative virulence genes of Trichomonas vaginalis: utility of targeted, selectable gene-replacement. Recent Res. Devel. Microbiology 8:97-119. PMID: PMCID:
Washington State University