title: Mycoplasma genitalium promotes epithelial crossing and peripheral blood mononuclear cell infection by HIV-1.
abstract: BACKGROUND
  Mycoplasma genitalium co-infection in HIV-infected individuals has been reported to increase the shedding of HIV in the urogenital region of females. To better understand this relationship, we investigated the influence of M. genitalium on the transmission and replication of HIV using an in vitro model.
  
  
  METHODS
  The Transwell co-culture system was employed to assess the crossing of an endocervical cell barrier by HIV-1. Immunocytochemistry and confocal microscopy were used to assess the distribution of the nectin-1 molecule on M. genitalium-infected epithelial cells of the End1/E6E7 endocervical cell line, grown as monolayers in the insert wells. Peripheral blood mononuclear cells (PBMC) were cultured in the bottom wells to assess the effects of M. genitalium, passing through the semipermeable culturing membrane, on subsequent HIV infection of susceptible target cells.
  
  
  RESULTS
  Infection of the endocervical cells with the adhesion-positive M. genitalium G37 strain (wild-type) significantly elevated the passage of HIV across the epithelial cell barrier relative to HIV transfer across endocervical cells infected with the adhesion-negative M. genitalium JB1 strain. Immunostaining of the M. genitalium-G37-infected epithelial cells disclosed capping and internalization of the junctional regulatory protein nectin-1, in association with reduced transepithelial resistance (TER) in the cell monolayer. When PBMC were cultured beneath insert wells containing M. genitalium-G37-infected epithelial cell monolayers, we observed significantly enhanced infectivity and replication of HIV added afterward to the cultures.
  
  
  CONCLUSIONS
  M. genitalium influences events on both sides of a cultured mucosal epithelial monolayer: (1) by infecting the epithelial cells and reducing the integrity of the barrier itself, and (2) by activating HIV target cells below it, thereby promoting HIV infection and progeny virus production.
authors.affiliation: Regional Academic Health Center and Department of Microbiology and Immunology, UT Health Science Center at San Antonio, Edinburg, TX 78541, USA; Center of Excellence in Infectious Diseases and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA.
authors.forename: Kishore
authors.initials: K
authors.lastname: Das
authors.affiliation: Regional Academic Health Center and Department of Microbiology and Immunology, UT Health Science Center at San Antonio, Edinburg, TX 78541, USA.
authors.forename: Georgina
authors.initials: G
authors.lastname: De la Garza
authors.affiliation: Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Edward B
authors.initials: EB
authors.lastname: Siwak
authors.affiliation: Regional Academic Health Center and Department of Microbiology and Immunology, UT Health Science Center at San Antonio, Edinburg, TX 78541, USA. Electronic address: scofieldv@uthscsa.edu.
authors.forename: Virginia L
authors.initials: VL
authors.lastname: Scofield
authors.affiliation: Regional Academic Health Center and Department of Microbiology and Immunology, UT Health Science Center at San Antonio, Edinburg, TX 78541, USA; Center of Excellence in Infectious Diseases and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA. Electronic address: s.dhandayuthapani@ttuhsc.edu.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Dhandayuthapani
mesh_terms: D000199:Actins / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D002584:Cervix Uteri / Q000166:cytology / Q000382:microbiology / Q000821:virology; D018920:Coculture Techniques; D060085:Coinfection; D004847:Epithelial Cells / Q000382:microbiology* / Q000821:virology*; D005260:Female; D015658:HIV Infections / Q000473:pathology / Q000635:transmission; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000382:microbiology* / Q000821:virology*; D009175:Mycoplasma Infections / Q000473:pathology; D045704:Mycoplasma genitalium; D000075983:Nectins; D062793:Occludin / Q000378:metabolism; D014779:Virus Replication
chemical_list: D000199:Actins; D015815:Cell Adhesion Molecules; C000619010:NECTIN1 protein, human; D000075983:Nectins; C568985:OCLN protein, human; D062793:Occludin
keywords: Co-infection; Epithelial barrier; HIV; Mycoplasma genitalium; Nectin-1; Sexually transmitted disease