G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo

IntroductionClinically, a dysbiotic vaginal microbiota (VMB) colonized with anaerobic species such as Gardnerella vaginalis has been linked to increased susceptibility to viral sexually transmitted infections (STIs) such as Herpes Simplex Virus Type 2 (HSV-2). The mechanism is poorly understood due...

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Main Authors: Nuzhat Rahman, M. Firoz Mian, Christina L. Hayes, Aisha Nazli, Charu Kaushic
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-11-01
Series:Frontiers in Immunology
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Online Access:https://www.frontiersin.org/articles/10.3389/fimmu.2024.1487726/full
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author Nuzhat Rahman
Nuzhat Rahman
M. Firoz Mian
M. Firoz Mian
Christina L. Hayes
Christina L. Hayes
Aisha Nazli
Aisha Nazli
Charu Kaushic
Charu Kaushic
author_facet Nuzhat Rahman
Nuzhat Rahman
M. Firoz Mian
M. Firoz Mian
Christina L. Hayes
Christina L. Hayes
Aisha Nazli
Aisha Nazli
Charu Kaushic
Charu Kaushic
author_sort Nuzhat Rahman
collection DOAJ
description IntroductionClinically, a dysbiotic vaginal microbiota (VMB) colonized with anaerobic species such as Gardnerella vaginalis has been linked to increased susceptibility to viral sexually transmitted infections (STIs) such as Herpes Simplex Virus Type 2 (HSV-2). The mechanism is poorly understood due to the lack of small animal models.MethodsMice were inoculated with 107 CFU of the eubiotic bacteria Lactobacillus crispatus, the dysbiotic bacteria G. vaginalis, or PBS as a negative control every 48 h for ten days. On day ten, mice were inoculated with 105 PFU WT HSV-2 333 and survival, pathology, and viral titers were assessed. To elucidate changes in the vaginal microenvironment following bacterial inoculations, vaginal tissue and washes were collected following ten days of inoculations. To assess barrier integrity, tissue was fixed and stained for the barrier protein Desmoglein-1 (DSG-1). To evaluate the immune microenvironment, tissue was processed for flow cytometry to examine tissue-resident T cells and cytokine production by T cells. Vaginal washes were used for multiplex cytokine/chemokine analysis.ResultsG. vaginalis inoculated mice infected with HSV-2 had significantly decreased survival rates, increased pathology, and higher viral titers than PBS and L. crispatus inoculated mice. The vaginal epithelium of G. vaginalis inoculated mice showed decreased DSG-1 staining compared to other groups, indicating compromised barrier function. Decreased total numbers of CD4+ and CD8+ T cells expressing activated mucosal immune markers CD44, CD69, and CD103 were observed in the vaginal tract of G. vaginalis inoculated mice. They also showed increased proportions of T cells expressing inflammatory cytokines TNF-α and IFN-γ, while L. crispatus inoculated mice had increased proportions and absolute counts of T cells expressing the regulatory cytokine IL-10. In the multiplex assay, vaginal washes from G. vaginalis mice had increased inflammatory cytokines and chemokines compared to L. crispatus and PBS groups.DiscussionThese results suggest G. vaginalis inoculation may be increasing HSV-2 infection by disrupting the epithelial barrier, decreasing protective immune responses and increasing tissue inflammation in the vaginal tract.
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spelling doaj-art-f54c0b21a51145cea689f91d572d957f2024-11-22T06:17:07ZengFrontiers Media S.A.Frontiers in Immunology1664-32242024-11-011510.3389/fimmu.2024.14877261487726G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivoNuzhat Rahman0Nuzhat Rahman1M. Firoz Mian2M. Firoz Mian3Christina L. Hayes4Christina L. Hayes5Aisha Nazli6Aisha Nazli7Charu Kaushic8Charu Kaushic9Department of Medicine, McMaster University, Hamilton, ON, CanadaMcMaster Immunology Research Center, Michael G. DeGroote Center for Learning and Discovery, McMaster University, Hamilton, ON, CanadaDepartment of Medicine, McMaster University, Hamilton, ON, CanadaMcMaster Immunology Research Center, Michael G. DeGroote Center for Learning and Discovery, McMaster University, Hamilton, ON, CanadaDepartment of Medicine, McMaster University, Hamilton, ON, CanadaMcMaster Immunology Research Center, Michael G. DeGroote Center for Learning and Discovery, McMaster University, Hamilton, ON, CanadaDepartment of Medicine, McMaster University, Hamilton, ON, CanadaMcMaster Immunology Research Center, Michael G. DeGroote Center for Learning and Discovery, McMaster University, Hamilton, ON, CanadaDepartment of Medicine, McMaster University, Hamilton, ON, CanadaMcMaster Immunology Research Center, Michael G. DeGroote Center for Learning and Discovery, McMaster University, Hamilton, ON, CanadaIntroductionClinically, a dysbiotic vaginal microbiota (VMB) colonized with anaerobic species such as Gardnerella vaginalis has been linked to increased susceptibility to viral sexually transmitted infections (STIs) such as Herpes Simplex Virus Type 2 (HSV-2). The mechanism is poorly understood due to the lack of small animal models.MethodsMice were inoculated with 107 CFU of the eubiotic bacteria Lactobacillus crispatus, the dysbiotic bacteria G. vaginalis, or PBS as a negative control every 48 h for ten days. On day ten, mice were inoculated with 105 PFU WT HSV-2 333 and survival, pathology, and viral titers were assessed. To elucidate changes in the vaginal microenvironment following bacterial inoculations, vaginal tissue and washes were collected following ten days of inoculations. To assess barrier integrity, tissue was fixed and stained for the barrier protein Desmoglein-1 (DSG-1). To evaluate the immune microenvironment, tissue was processed for flow cytometry to examine tissue-resident T cells and cytokine production by T cells. Vaginal washes were used for multiplex cytokine/chemokine analysis.ResultsG. vaginalis inoculated mice infected with HSV-2 had significantly decreased survival rates, increased pathology, and higher viral titers than PBS and L. crispatus inoculated mice. The vaginal epithelium of G. vaginalis inoculated mice showed decreased DSG-1 staining compared to other groups, indicating compromised barrier function. Decreased total numbers of CD4+ and CD8+ T cells expressing activated mucosal immune markers CD44, CD69, and CD103 were observed in the vaginal tract of G. vaginalis inoculated mice. They also showed increased proportions of T cells expressing inflammatory cytokines TNF-α and IFN-γ, while L. crispatus inoculated mice had increased proportions and absolute counts of T cells expressing the regulatory cytokine IL-10. In the multiplex assay, vaginal washes from G. vaginalis mice had increased inflammatory cytokines and chemokines compared to L. crispatus and PBS groups.DiscussionThese results suggest G. vaginalis inoculation may be increasing HSV-2 infection by disrupting the epithelial barrier, decreasing protective immune responses and increasing tissue inflammation in the vaginal tract.https://www.frontiersin.org/articles/10.3389/fimmu.2024.1487726/fullvaginal microbiota (VMB)Lactobacillusbacterial vaginosisherpes simplex virusinflammationbarrier integrity
spellingShingle Nuzhat Rahman
Nuzhat Rahman
M. Firoz Mian
M. Firoz Mian
Christina L. Hayes
Christina L. Hayes
Aisha Nazli
Aisha Nazli
Charu Kaushic
Charu Kaushic
G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
Frontiers in Immunology
vaginal microbiota (VMB)
Lactobacillus
bacterial vaginosis
herpes simplex virus
inflammation
barrier integrity
title G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
title_full G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
title_fullStr G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
title_full_unstemmed G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
title_short G. vaginalis increases HSV-2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
title_sort g vaginalis increases hsv 2 infection by decreasing vaginal barrier integrity and increasing inflammation in vivo
topic vaginal microbiota (VMB)
Lactobacillus
bacterial vaginosis
herpes simplex virus
inflammation
barrier integrity
url https://www.frontiersin.org/articles/10.3389/fimmu.2024.1487726/full
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