Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro

ABSTRACT Vav proteins are guanine exchange factors that activate Rac1/RhoA signaling to regulate many biological processes including inflammatory responses. Here, the expression and functional significance of Vav’s were investigated during dengue virus (DENV) infection. In primary monocyte-derived m...

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Main Authors: Evangeline Cowell, Hawraa Jaber, Luke P. Kris, Madeleine G. Fitzgerald, Valeria M. Sanders, Aidan J. Norbury, Nicholas S. Eyre, Jillian M. Carr
Format: Article
Language:English
Published: American Society for Microbiology 2024-01-01
Series:Microbiology Spectrum
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/spectrum.02391-23
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author Evangeline Cowell
Hawraa Jaber
Luke P. Kris
Madeleine G. Fitzgerald
Valeria M. Sanders
Aidan J. Norbury
Nicholas S. Eyre
Jillian M. Carr
author_facet Evangeline Cowell
Hawraa Jaber
Luke P. Kris
Madeleine G. Fitzgerald
Valeria M. Sanders
Aidan J. Norbury
Nicholas S. Eyre
Jillian M. Carr
author_sort Evangeline Cowell
collection DOAJ
description ABSTRACT Vav proteins are guanine exchange factors that activate Rac1/RhoA signaling to regulate many biological processes including inflammatory responses. Here, the expression and functional significance of Vav’s were investigated during dengue virus (DENV) infection. In primary monocyte-derived macrophages, Vav1, −2, and −3 mRNA levels demonstrate variable responses to DENV infection and correlate with DENV-induced host inflammatory (IL-6 and TNF-α), antiviral (viperin), or cell adhesion [intercellular cell adhesion molecule (ICAM-1)] mRNA induction. Strong positive correlations were seen in particular for Vav2 with TNF-α and Vav3 with IL-6 mRNA. In the retinal pigmented epithelial cell line, ARPE-19, Vav2 was the main Vav expressed and was not affected by DENV infection. Heterologous Vav1 expression in ARPE-19 cells induced an increase in basal IL-6 mRNA but did not enhance DENV-induced mRNA responses. DENV RNA and DENV-induced viperin and IL-6 mRNA responses were also unaffected by Vav2 siRNA knockdown. Treatment of DENV-infected ARPE-19 cells with EHop-016 to block Vav signaling did not affect DENV RNA levels but increased DENV-mediated induction of IL-6 mRNA. More detailed assessment of DENV-induced responses to azathioprine, a clinically used immunosuppressant that can also block Vav signaling and act as a nucleoside analog, similarly demonstrated no change in DENV RNA levels but resulted in inhibition of DENV-induced phospho-ERK and increased DENV-induced-IL-6 and viperin mRNA in ARPE-19 cells. Thus, levels of Vav are associated with DENV-induced inflammatory responses, and blocking Vav signaling pathways does not compromise control of viral replication but may influence DENV-induced host responses. IMPORTANCE Dengue disease is characterized by an inflammatory-mediated immunopathology, with elevated levels of circulating factors including TNF-α and IL-6. If the damaging inflammatory pathways could be blocked without loss of antiviral responses or exacerbating viral replication, then this would be of potential therapeutic benefit. The study here has investigated the Vav guanine exchange factors as a potential alternative signaling pathway that may drive dengue virus (DENV)-induced inflammatory responses, with a focus on Vav1 and 2. While Vav proteins were positively associated with mRNA for inflammatory cytokines, blocking Vav signaling didn’t affect DENV replication but prevented DENV-induction of p-ERK and enhanced IL-6 (inflammatory) and viperin (antiviral) mRNA. These initial data suggest that Vav proteins could be a target that does not compromise control of viral replication and should be investigated further for broader impact on host inflammatory responses, in settings such as antibody-dependent enhancement of infection and in different cell types.
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spelling doaj.art-db36f6f0df084dcf994127bb0bba593a2024-01-11T14:04:37ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972024-01-0112110.1128/spectrum.02391-23Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitroEvangeline Cowell0Hawraa Jaber1Luke P. Kris2Madeleine G. Fitzgerald3Valeria M. Sanders4Aidan J. Norbury5Nicholas S. Eyre6Jillian M. Carr7College of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaCollege of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaCollege of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaCollege of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaCollege of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaFaculty of Health and Medical Sciences, University of Adelaide , Adelaide, South Australia, AustraliaCollege of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaCollege of Medicine and Public Health and Flinders Health and Medical Research Institute, Flinders University , Bedford Park, Adelaide, South Australia, AustraliaABSTRACT Vav proteins are guanine exchange factors that activate Rac1/RhoA signaling to regulate many biological processes including inflammatory responses. Here, the expression and functional significance of Vav’s were investigated during dengue virus (DENV) infection. In primary monocyte-derived macrophages, Vav1, −2, and −3 mRNA levels demonstrate variable responses to DENV infection and correlate with DENV-induced host inflammatory (IL-6 and TNF-α), antiviral (viperin), or cell adhesion [intercellular cell adhesion molecule (ICAM-1)] mRNA induction. Strong positive correlations were seen in particular for Vav2 with TNF-α and Vav3 with IL-6 mRNA. In the retinal pigmented epithelial cell line, ARPE-19, Vav2 was the main Vav expressed and was not affected by DENV infection. Heterologous Vav1 expression in ARPE-19 cells induced an increase in basal IL-6 mRNA but did not enhance DENV-induced mRNA responses. DENV RNA and DENV-induced viperin and IL-6 mRNA responses were also unaffected by Vav2 siRNA knockdown. Treatment of DENV-infected ARPE-19 cells with EHop-016 to block Vav signaling did not affect DENV RNA levels but increased DENV-mediated induction of IL-6 mRNA. More detailed assessment of DENV-induced responses to azathioprine, a clinically used immunosuppressant that can also block Vav signaling and act as a nucleoside analog, similarly demonstrated no change in DENV RNA levels but resulted in inhibition of DENV-induced phospho-ERK and increased DENV-induced-IL-6 and viperin mRNA in ARPE-19 cells. Thus, levels of Vav are associated with DENV-induced inflammatory responses, and blocking Vav signaling pathways does not compromise control of viral replication but may influence DENV-induced host responses. IMPORTANCE Dengue disease is characterized by an inflammatory-mediated immunopathology, with elevated levels of circulating factors including TNF-α and IL-6. If the damaging inflammatory pathways could be blocked without loss of antiviral responses or exacerbating viral replication, then this would be of potential therapeutic benefit. The study here has investigated the Vav guanine exchange factors as a potential alternative signaling pathway that may drive dengue virus (DENV)-induced inflammatory responses, with a focus on Vav1 and 2. While Vav proteins were positively associated with mRNA for inflammatory cytokines, blocking Vav signaling didn’t affect DENV replication but prevented DENV-induction of p-ERK and enhanced IL-6 (inflammatory) and viperin (antiviral) mRNA. These initial data suggest that Vav proteins could be a target that does not compromise control of viral replication and should be investigated further for broader impact on host inflammatory responses, in settings such as antibody-dependent enhancement of infection and in different cell types.https://journals.asm.org/doi/10.1128/spectrum.02391-23dengue virusVavinflammationazathioprineinterleukin-6viperin
spellingShingle Evangeline Cowell
Hawraa Jaber
Luke P. Kris
Madeleine G. Fitzgerald
Valeria M. Sanders
Aidan J. Norbury
Nicholas S. Eyre
Jillian M. Carr
Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro
Microbiology Spectrum
dengue virus
Vav
inflammation
azathioprine
interleukin-6
viperin
title Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro
title_full Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro
title_fullStr Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro
title_full_unstemmed Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro
title_short Vav proteins do not influence dengue virus replication but are associated with induction of phospho-ERK, IL-6, and viperin mRNA following DENV infection in vitro
title_sort vav proteins do not influence dengue virus replication but are associated with induction of phospho erk il 6 and viperin mrna following denv infection in vitro
topic dengue virus
Vav
inflammation
azathioprine
interleukin-6
viperin
url https://journals.asm.org/doi/10.1128/spectrum.02391-23
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