scholarly journals Novel Insights into the Molecular Events Linking to Cell Death Induced by Tetracycline in the Amitochondriate Protozoan Trichomonas vaginalis

2015 ◽  
Vol 59 (11) ◽  
pp. 6891-6903 ◽  
Author(s):  
Kuo-Yang Huang ◽  
Fu-Man Ku ◽  
Wei-Hung Cheng ◽  
Chi-Ching Lee ◽  
Po-Jung Huang ◽  
...  
Keyword(s):  
Cell Death ◽  
Trichomonas Vaginalis ◽  
Transmitted Disease ◽  
Chemotherapeutic Agents ◽  
Public Health Issue ◽  
Rna Seq ◽  
Content Type ◽  
Sexually Transmitted ◽  
Molecular Events

ABSTRACTTrichomonas vaginaliscolonizes the human urogenital tract and causes trichomoniasis, the most common nonviral sexually transmitted disease. Currently, 5-nitroimidazoles are the only recommended drugs for treating trichomoniasis. However, increased resistance of the parasite to 5-nitroimidazoles has emerged as a highly problematic public health issue. Hence, it is essential to identify alternative chemotherapeutic agents against refractory trichomoniasis. Tetracycline (TET) is a broad-spectrum antibiotic with activity against several protozoan parasites, but the mode of action of TET in parasites remains poorly understood. Thein vitroeffect of TET on the growth ofT. vaginaliswas examined, and the mode of cell death was verified by various apoptosis-related assays. Next-generation sequencing-based RNA sequencing (RNA-seq) was employed to elucidate the transcriptome ofT. vaginalisin response to TET. We show that TET has a cytotoxic effect on both metronidazole (MTZ)-sensitive and -resistantT. vaginalisisolates, inducing some features resembling apoptosis. RNA-seq data reveal that TET significantly alters the transcriptome via activation of specific pathways, such as aminoacyl-tRNA synthetases and carbohydrate metabolism. Functional analyses demonstrate that TET disrupts the hydrogenosomal membrane potential and antioxidant system, which concomitantly elicits a metabolic shift toward glycolysis, suggesting that the hydrogenosomal function is impaired and triggers cell death. Collectively, we providein vitroevidence that TET is a potential alternative therapeutic choice for treating MTZ-resistantT. vaginalis. The in-depth transcriptomic signatures inT. vaginalisupon TET treatment presented here will shed light on the signaling pathways linking to cell death in amitochondriate organisms.

A Review on Herbal Treatments for Trichomonas Vaginalis

2021 ◽  
Author(s):  
Fatemeh Rahmani ◽  
Yahya Ehteshaminia ◽  
Hamid Mohammadi ◽  
Seif Ali Mahdavi
Keyword(s):  
Side Effects ◽  
Trichomonas Vaginalis ◽  
Transmitted Disease ◽  
Protozoan Parasite ◽  
Patient Acceptance ◽  
Therapeutic Effects ◽  
Men And Women ◽  
Sexually Transmitted ◽  
Advantages And Disadvantages

Introduction: Trichomonas vaginalis is a protozoan parasite that infects the urogenital tract of men and women and causes trichomoniasis, a common sexually transmitted disease in both men and women. The infection is often asymptomatic, but it can be accompanied by symptoms such as severe inflammation, itching and burning, foamy discharge and foul-smelling mucus. In one year, 250 million cases of Trichomonas vaginalis were reported worldwide. Material and Methods: In this study, the websites of PubMed, Google Scholar, SID, and Margiran were searched and related articles were reviewed.    Results: Today, the most common treatment for this disease is the use of metronidazole. However, its side effects, which include hematological and neurotoxic effects, cannot be ignored. Because of these side effects, researchers are looking for a suitable replacement for metronidazole in the treatment of trichomoniasis. Researchers' desire to use  herbs can be due to various reasons such as fewer side effects, better patient acceptance, recommendation of traditional medicine, lower prices of herbs and also compatibility with the normal physiological function of the human body. Conclusion: Considering the inhibitory effects of medicinal plants on the growth and proliferation of Trichomonas vaginalis in vitro, it can be concluded that the use of these plants can have many applications in the treatment of trichomoniasis. As a result, by studying more about their advantages and disadvantages, it is possible to make a drug that has higher therapeutic effects with fewer side effects.

Zinc-clotrimazole complexes are effective against Trichomonas vaginalis

Parasitology ◽  
2019 ◽  
Vol 146 (9) ◽  
pp. 1206-1216 ◽  
Author(s):  
Victor Midlej ◽  
Felipe Rubim ◽  
Wilmer Villarreal ◽  
Érica S. Martins-Duarte ◽  
Maribel Navarro ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Transmitted Disease ◽  
Protozoan Parasite ◽  
Parasite Resistance ◽  
Zinc Compounds ◽  
Sexually Transmitted ◽  
Transmission Electron ◽  
Zinc Salts ◽  
Imidazole Compounds

AbstractTrichomonas vaginalis is a protozoan parasite that causes trichomoniasis in humans, the most prevalent non-viral sexually transmitted disease (STD). Imidazole compounds are used for the treatment of trichomoniasis, and metronidazole is the most commonly prescribed. However, these compounds can lead to parasite resistance and unwanted side effects. Therefore, there is a need for an alternative treatment for this disease. Here, we explored the potential of clotrimazole (CTZ) and zinc compounds, as well as CTZ complexed with zinc salts ([1] acetate [Zn(CTZ)2(Ac)2] and [2] a chloride [Zn(CTZ)2Cl2] complexes) against T. vaginalis. We synthesized the zinc complexed CTZ compounds and determined their concentration values that inhibited parasite growth by 50% (IC50). We used scanning and transmission electron microscopy to visualize the ultrastructural alterations induced by CTZ and their zinc complexes. The incubation of the parasites with [Zn(CTZ)2(Ac)2] complex inhibited their growth, yielding an IC50 of 4.9 µm. Moreover, there were changes in the shape of treated parasites, including the formation of surface projections that subsequently detached from the cell, in addition to changes in the hydrogenosomes, endoplasmic reticulum and Golgi complex. We found [Zn(CTZ)2(Ac)2] to be a highly effective compound against T. vaginalis in vitro, suggesting its potential utility as an alternative chemotherapy for trichomoniasis.

scholarly journals Novel Trichomonacidal Spermicides

2011 ◽  
Vol 55 (9) ◽  
pp. 4343-4351 ◽  
Author(s):  
Ashish Jain ◽  
Nand Lal ◽  
Lokesh Kumar ◽  
Vikas Verma ◽  
Rajeev Kumar ◽  
...  
Keyword(s):  
Hela Cells ◽  
Trichomonas Vaginalis ◽  
Human Sperm ◽  
Content Type ◽  
Sexually Transmitted ◽  
Vaginal Microflora ◽  
Anaerobic Energy ◽  
Resistant Strains ◽  
New Compounds

ABSTRACTMetronidazole, the U.S. Food and Drug Administration-approved drug against trichomoniasis, is nonspermicidal and thus cannot offer pregnancy protection when used vaginally. Furthermore, increasing resistance ofTrichomonas vaginalisto 5-nitro-imidazoles is a cause for serious concern. On the other hand, the vaginal spermicide nonoxynol-9 (N-9) does not protect against sexually transmitted diseases and HIV in clinical situations but may in fact increase their incidence due to its nonspecific, surfactant action. We therefore designed dually active, nonsurfactant molecules that were capable of killingTrichomonas vaginalis(both metronidazole-susceptible and -resistant strains) and irreversibly inactivating 100% human sperm at doses that were noncytotoxic to human cervical epithelial (HeLa) cells and vaginal microflora (lactobacilli)in vitro. Anaerobic energy metabolism, cell motility, and defense against reactive oxygen species, which are key to survival of both sperm andTrichomonasin the host after intravaginal inoculation, depend crucially on availability of free thiols. Consequently, molecules were designed with carbodithioic acid moiety as the major pharmacophore, and chemical variations were incorporated to provide high excess of reactive thiols for interacting with accessible thiols on sperm andTrichomonas. We report here thein vitroactivities, structure-activity relationships, and safety profiles of these spermicidal antitrichomonas agents, the most promising of which was more effective than N-9 (the OTC spermicide) in inactivating human sperm and more efficacious than metronidazole in killingTrichomonas vaginalis(including metronidazole-resistant strain). It also significantly reduced the available free thiols on human sperm and inhibited the cytoadherence ofTrichomonason HeLa cells. Experimentallyin vitro, the new compounds appeared to be safer than N-9 for vaginal use.

Molecular Epidemiology of Metronidazole Resistance in a Population of Trichomonas vaginalis Clinical Isolates

2000 ◽  
Vol 38 (8) ◽  
pp. 3004-3009 ◽  
Author(s):  
Lauren J. Snipes ◽  
Pascale M. Gamard ◽  
Elizabeth M. Narcisi ◽  
C. Ben Beard ◽  
Tovi Lehmann ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Trichomonas Vaginalis ◽  
Random Amplified Polymorphic Dna ◽  
Transmitted Disease ◽  
Clinical Isolates ◽  
Nucleotide Position ◽  
Sexually Transmitted ◽  
Metronidazole Resistance ◽  
High Level

Trichomonas vaginalis, the causative agent for human trichomoniasis, is a problematic sexually transmitted disease mainly in women, where it may be asymptomatic or cause severe vaginitis and cervicitis. Despite its high prevalence, the genetic variability and drug resistance characteristics of this organism are poorly understood. To address these issues, genetic analyses were performed on 109 clinical isolates using three approaches. First, two internal transcribed spacer (ITS) regions flanking the 5.8S subunit of the ribosomal DNA gene were sequenced. The only variation was a point mutation at nucleotide position 66 of the ITS1 region found in 16 isolates (14.7%). Second, the presence of a 5.5-kb double-stranded RNAT. vaginalis virus (TVV) was assessed. TVV was detected in 55 isolates (50%). Finally, a phylogenetic analysis was performed based on random amplified polymorphic DNA data. The resulting phylogeny indicated at least two distinct lineages that correlate with the presence of TVV. A band-sharing index indicating relatedness was created for different groups of isolates. It demonstrated that isolates harboring the virus are significantly more closely related to each other than to the rest of the population, and it indicated a high level of relatedness among isolates with in vitro metronidazole resistance. This finding is consistent with the hypothesis that drug resistance toT. vaginalis resulted from a single or very few mutational events. Permutation tests and nonparametric analyses showed associations between metronidazole resistance and phylogeny, the ITS mutation, and TVV presence. These results suggest the existence of genetic markers with clinical implications for T. vaginalisinfections.

scholarly journals Structure of the RecombinantNeisseria gonorrhoeaeAdhesin Complex Protein (rNg-ACP) and Generation of Murine Antibodies with Bactericidal Activity against Gonococci

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Hannia Liliana Almonacid-Mendoza ◽  
María Victoria Humbert ◽  
Aiste Dijokaite ◽  
David W. Cleary ◽  
Yiwen Soo ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Sexually Transmitted Disease ◽  
Transmitted Disease ◽  
Causative Organism ◽  
Human Lysozyme ◽  
Content Type ◽  
Sexually Transmitted ◽  
Innate Defense ◽  
Complex Protein

ABSTRACTNeisseria gonorrhoeae(gonococcus [Ng]) is the causative organism of the sexually transmitted disease gonorrhoea, and no effective vaccine exists currently. In this study, the structure, biological properties, and vaccine potential of the Ng-adhesin complex protein (Ng-ACP) are presented. The crystal structure of recombinant Ng-ACP (rNg-ACP) protein was solved at 1.65 Å. Diversity and conservation of Ng-ACP were examined in differentNeisseriaspecies and gonococcal isolates (https://pubmlst.org/neisseria/database)in silico, and protein expression among 50 gonococcal strains in the Centers for Disease Control and Prevention/Food and Drug Administration (CDCP/FDA) AR Isolate Bank was examined by Western blotting. Murine antisera were raised to allele 10 (strain P9-17)-encoded rNg-ACP protein with different adjuvants and examined by enzyme-linked immunosorbent assay (ELISA), Western blotting, and a human serum bactericidal assay. Rabbit antiserum to rNg-ACP was tested for its ability to prevent Ng-ACP from inhibiting human lysozyme activityin vitro.Ng-ACP is structurally homologous toNeisseria meningitidisACP and MliC/PliC lysozyme inhibitors. Gonococci expressed predominantly allele 10- and allele 6-encoded Ng-ACP (81% and 15% of isolates, respectively). Murine antisera were bactericidal (titers of 64 to 512,P < 0.05) for the homologous P9-17 strain and heterologous (allele 6) FA1090 strain. Rabbit anti-rNg-ACP serum prevented Ng-ACP from inhibiting human lysozyme with ∼100% efficiency. Ng-ACP protein was expressed by all 50 gonococcal isolates examined with minor differences in the relative levels of expression. rNg-ACP is a potential vaccine candidate that induces antibodies that (i) are bactericidal and (ii) prevent the gonococcus from inhibiting the lytic activity of an innate defense molecule.IMPORTANCENeisseria gonorrhoeae(gonococcus [Ng]) is the causative organism of the sexually transmitted disease gonorrhoea, and the organism is listed by the World Health Organization as a high-priority pathogen for research and development of new control measures, including vaccines. In this study, we demonstrated that theN. gonorrhoeaeadhesin complex protein (Ng-ACP) was conserved and expressed by 50 gonococcal strains and that recombinant proteins induced antibodies in mice that killed the bacteriain vitro. We determined the structure of Ng-ACP by X-ray crystallography and investigated structural conservation withNeisseria meningitidisACP and MliC/PliC proteins from other bacteria which act as inhibitors of the human innate defense molecule lysozyme. These findings are important and suggest that Ng-ACP could provide a potential dual target for tackling gonococcal infections.

scholarly journals 20S Proteasome as a Drug Target in Trichomonas vaginalis

2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Anthony J. O’Donoghue ◽  
Betsaida Bibo-Verdugo ◽  
Yukiko Miyamoto ◽  
Steven C Wang ◽  
Justin Z. Yang ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Critical Role ◽  
Transmitted Disease ◽  
Proteasome Inhibitors ◽  
Parasite Burden ◽  
Marine Natural Product ◽  
Reference Drug ◽  
Content Type ◽  
Proteasome Subunits

ABSTRACT Trichomoniasis is a sexually transmitted disease with hundreds of millions of annual cases worldwide. Approved treatment options are limited to two related nitro-heterocyclic compounds, yet resistance to these drugs is an increasing concern. New antimicrobials against the causative agent, Trichomonas vaginalis, are urgently needed. We show here that clinically approved anticancer drugs that inhibit the proteasome, a large protease complex with a critical role in degrading intracellular proteins in eukaryotes, have submicromolar activity against the parasite in vitro and on-target activity against the enriched T. vaginalis proteasome in cell-free assays. Proteomic analysis confirmed that the parasite has all seven α and seven β subunits of the eukaryotic proteasome although they have only modest sequence identities, ranging from 28 to 52%, relative to the respective human proteasome subunits. A screen of proteasome inhibitors derived from a marine natural product, carmaphycin, revealed one derivative, carmaphycin-17, with greater activity against T. vaginalis than the reference drug metronidazole, the ability to overcome metronidazole resistance, and reduced human cytotoxicity compared to that of the anticancer proteasome inhibitors. The increased selectivity of carmaphycin-17 for T. vaginalis was related to its >5-fold greater potency against the β1 and β5 catalytic subunits of the T. vaginalis proteasome than against the human proteasome subunits. In a murine model of vaginal trichomonad infection, proteasome inhibitors eliminated or significantly reduced parasite burden upon topical treatment without any apparent adverse effects. Together, these findings validate the proteasome of T. vaginalis as a therapeutic target for development of a novel class of trichomonacidal agents.

scholarly journals Clinical Evaluation of the Cepheid Xpert TV Assay for Detection of Trichomonas vaginalis with Prospectively Collected Specimens from Men and Women

2017 ◽  
Vol 56 (2) ◽  
Author(s):  
Jane R. Schwebke ◽  
C. A. Gaydos ◽  
T. Davis ◽  
J. Marrazzo ◽  
D. Furgerson ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Transmitted Disease ◽  
The United States ◽  
Nucleic Acid Amplification ◽  
Urine Samples ◽  
Broth Culture ◽  
Men And Women ◽  
Content Type ◽  
Sexually Transmitted ◽  
Diagnostic Sensitivity And Specificity

ABSTRACT Trichomoniasis is the most prevalent curable sexually transmitted disease (STD). It has been associated with preterm birth and the acquisition and transmission of HIV. Recently, nucleic acid amplification tests (NAAT) have been FDA cleared in the United States for detection of Trichomonas vaginalis in specimens from both women and men. This study reports the results of a multicenter study recently conducted using the Xpert TV (T. vaginalis) assay to test specimens from both men and women. On-demand results were available in as little as 40 min for positive specimens. A total of 1,867 women and 4,791 men were eligible for inclusion in the analysis. In women, the performance of the Xpert TV assay was compared to the patient infected status (PIS) derived from the results of InPouch TV broth culture and Aptima NAAT for T. vaginalis. The diagnostic sensitivities and specificities of the Xpert TV assay for the combined female specimens (urine samples, self-collected vaginal swabs, and endocervical swabs) ranged from 99.5 to 100% and 99.4 to 99.9%, respectively. For male urine samples, the diagnostic sensitivity and specificity were 97.2% and 99.9%, respectively, compared to PIS results derived from the results of broth culture for T. vaginalis and bidirectional gene sequencing of amplicons. Excellent performance characteristics were seen using both female and male specimens. The ease of using the Xpert TV assay should result in opportunities for enhanced screening for T. vaginalis in both men and women and, hopefully, improved control of this infection.

scholarly journals The ProtozoanTrichomonas vaginalisTargets Bacteria with Laterally Acquired NlpC/P60 Peptidoglycan Hydrolases

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Jully Pinheiro ◽  
Jacob Biboy ◽  
Waldemar Vollmer ◽  
Robert P. Hirt ◽  
Jeremy R. Keown ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Close Association ◽  
Transmitted Disease ◽  
Mixed Cultures ◽  
Vaginal Mucosa ◽  
Transmitted Infection ◽  
Content Type ◽  
Sexually Transmitted ◽  
Study Results ◽  
Peptidoglycan Hydrolases

ABSTRACTThe human eukaryotic pathogenTrichomonas vaginaliscauses trichomoniasis, a prevalent sexually transmitted infection. This extracellular protozoan is intimately associated with the human vaginal mucosa and microbiota, but key aspects of the complex interactions between the parasite and the vaginal bacteria remain elusive. We report thatT. vaginalishas acquired, by lateral gene transfer from bacteria, genes encoding peptidoglycan hydrolases of the NlpC/P60 family. Two of theT. vaginalisenzymes were active against bacterial peptidoglycan, retaining the active-site fold and specificity asdl-endopeptidases. The endogenous NlpC/P60 genes are transcriptionally upregulated inT. vaginalisin the presence of bacteria. The overexpression of an exogenous copy enables the parasite to outcompete bacteria from mixed cultures, consistent with the biochemical activity of the enzyme. Our study results highlight the relevance of the interactions of this eukaryotic pathogen with bacteria, a poorly understood aspect of the biology of this important human parasite.IMPORTANCETrichomonas vaginalisis a parasitic protozoan of the human urogenital tract that causes trichomoniasis, a very common sexually transmitted disease. Despite residing extracellularly and in close association with the vaginal bacteria (i.e., the microbiota), very little is known about the nature of the parasite-bacterium interactions. Our study showed that this parasite had acquired genes from bacteria which retained their original function. They produce active enzymes capable of degrading peptidoglycan, a unique polymer of the bacterial cell envelope, helping the parasite to outcompete bacteria in mixed cultures. This study was the first to show that a laterally acquired group of genes enables a eukaryotic mucosal pathogen to control bacterial population. We highlight the importance of understanding the interactions between pathogens and microbiota, as the outcomes of these interactions are increasingly understood to have important implications on health and disease.

scholarly journals Structure of a Protozoan Virus from the Human Genitourinary Parasite Trichomonas vaginalis

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Kristin N. Parent ◽  
Yuko Takagi ◽  
Giovanni Cardone ◽  
Norman H. Olson ◽  
Maria Ericsson ◽  
...  
Keyword(s):  
Viral Genome ◽  
Trichomonas Vaginalis ◽  
Transmitted Disease ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Ribosomal Frameshifting ◽  
Double Stranded Rna ◽  
Content Type ◽  
Sexually Transmitted ◽  
Dsrna Viruses

ABSTRACTThe flagellated protozoanTrichomonas vaginalisis an obligate human genitourinary parasite and the most frequent cause of sexually transmitted disease worldwide. Most clinical isolates ofT. vaginalisare persistently infected with one or more double-stranded RNA (dsRNA) viruses from the genusTrichomonasvirus, familyTotiviridae, which appear to influence not only protozoan biology but also human disease. Here we describe the three-dimensional structure ofTrichomonas vaginalisvirus 1 (TVV1) virions, as determined by electron cryomicroscopy and icosahedral image reconstruction. The structure reveals aT= 1 capsid comprising 120 subunits, 60 in each of two nonequivalent positions, designated A and B, as previously observed for fungalTotiviridaefamily members. The putative protomer is identified as an asymmetric AB dimer consistent with either decamer or tetramer assembly intermediates. The capsid surface is notable for raised plateaus around the icosahedral 5-fold axes, with canyons connecting the 2- and 3-fold axes. Capsid-spanning channels at the 5-fold axes are unusually wide and may facilitate release of the viral genome, promoting dsRNA-dependent immunoinflammatory responses, as recently shown upon the exposure of human cervicovaginal epithelial cells to either TVV-infectedT. vaginalisor purified TVV1 virions. Despite extensive sequence divergence, conservative features of the capsid reveal a helix-rich fold probably derived from an ancestor shared with fungalTotiviridaefamily members. Also notable are mass spectrometry results assessing the virion proteins as a complement to structure determination, which suggest that translation of the TVV1 RNA-dependent RNA polymerase in fusion with its capsid protein involves −2, and not +1, ribosomal frameshifting, an uncommonly found mechanism to date.IMPORTANCETrichomonas vaginaliscauses ~250 million new cases of sexually transmitted disease each year worldwide and is associated with serious complications, including premature birth and increased transmission of other pathogens, including HIV. It is an extracellular parasite that, in turn, commonly hosts infections with double-stranded RNA (dsRNA) viruses, trichomonasviruses, which appear to exacerbate disease through signaling of immunoinflammatory responses by human epithelial cells. Here we report the first three-dimensional structure of a trichomonasvirus, which is also the first such structure of any protozoan dsRNA virus; show that it has unusually wide channels at the capsid vertices, with potential for releasing the viral genome and promoting dsRNA-dependent responses by human cells; and provide evidence that it uses −2 ribosomal frameshifting, an uncommon mechanism, to translate its RNA polymerase in fusion with its capsid protein. These findings provide both mechanistic and translational insights concerning the role of trichomonasviruses in aggravating disease attributable toT. vaginalis.

scholarly journals Small RNAs Are Implicated in Regulation of Gene and Transposable Element Expression in the Protist Trichomonas vaginalis

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Sally D. Warring ◽  
Frances Blow ◽  
Grace Avecilla ◽  
Jordan C. Orosco ◽  
Steven A. Sullivan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Rna ◽  
Trichomonas Vaginalis ◽  
Repetitive Elements ◽  
Rna Seq ◽  
Transmitted Infection ◽  
Protein Coding ◽  
Content Type ◽  
Rna Molecules ◽  
Sexually Transmitted

ABSTRACT Trichomonas vaginalis is the causative agent of trichomoniasis, the most prevalent nonviral sexually transmitted infection worldwide. Repetitive elements, including transposable elements (TEs) and virally derived repeats, comprise more than half of the ∼160-Mb T. vaginalis genome. An intriguing question is how the parasite controls its potentially lethal complement of mobile elements, which can disrupt transcription of protein-coding genes and genome functions. In this study, we generated high-throughput RNA sequencing (RNA-Seq) and small RNA-Seq data sets in triplicate for the T. vaginalis G3 reference strain and characterized the mRNA and small RNA populations and their mapping patterns along all six chromosomes. Mapping the RNA-Seq transcripts to the genome revealed that the majority of genes predicted within repetitive elements are not expressed. Interestingly, we identified a novel species of small RNA that maps bidirectionally along the chromosomes and is correlated with reduced protein-coding gene expression and reduced RNA-Seq coverage in repetitive elements. This novel small RNA family may play a regulatory role in gene and repetitive element expression. Our results identify a possible small RNA pathway mechanism by which the parasite regulates expression of genes and TEs and raise intriguing questions as to the role repeats may play in shaping T. vaginalis genome evolution and the diversity of small RNA pathways in general. IMPORTANCE Trichomoniasis, caused by the protozoan Trichomonas vaginalis, is the most common nonviral sexually transmitted infection in humans. The millions of cases each year have sequelae that may include complications during pregnancy and increased risk of HIV infection. Given its evident success in this niche, it is paradoxical that T. vaginalis harbors in its genome thousands of transposable elements that have the potential to be extremely detrimental to normal genomic function. In many organisms, transposon expression is regulated by the activity of endogenously expressed short (∼21 to 35 nucleotides [nt]) small RNA molecules that effect gene silencing by targeting mRNAs for degradation or by recruiting epigenetic silencing machinery to locations in the genome. Our research has identified small RNA molecules correlated with reduced expression of T. vaginalis genes and transposons. This suggests that a small RNA pathway is a major contributor to gene expression patterns in the parasite and opens up new avenues for investigation into small RNA biogenesis, function, and diversity.

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