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Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases

INTRODUCTION: MDSCs express SCHLAFEN 4 (SLFN4) in Helicobacter-infected stomachs coincident with spasmolytic polypeptide-expressing metaplasia (SPEM), a precursor of gastric cancer. We aimed to characterize SLFN4(+) cell identity and the role of Slfn4 in these cells. METHODS: Single-cell RNA sequenc...

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Autores principales: Ding, Lin, Sheriff, Sulaiman, Sontz, Ricky A., Merchant, Juanita L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10272601/
https://www.ncbi.nlm.nih.gov/pubmed/37334372
http://dx.doi.org/10.3389/fimmu.2023.1139391
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author Ding, Lin
Sheriff, Sulaiman
Sontz, Ricky A.
Merchant, Juanita L.
author_facet Ding, Lin
Sheriff, Sulaiman
Sontz, Ricky A.
Merchant, Juanita L.
author_sort Ding, Lin
collection PubMed
description INTRODUCTION: MDSCs express SCHLAFEN 4 (SLFN4) in Helicobacter-infected stomachs coincident with spasmolytic polypeptide-expressing metaplasia (SPEM), a precursor of gastric cancer. We aimed to characterize SLFN4(+) cell identity and the role of Slfn4 in these cells. METHODS: Single-cell RNA sequencing was performed on immune cells sorted from PBMCs and stomachs prepared from uninfected and 6-month H. felis-infected mice. Knockdown of Slfn4 by siRNA or PDE5/6 inhibition by sildenafil were performed in vitro. Intracellular ATP/GTP levels and GTPase activity of immunoprecipitated Slfn4 complexes were measured using the GTPase-Glo assay kit. The intracellular level of ROS was quantified by the DCF-DA fluorescent staining, and apoptosis was determined by cleaved Caspase-3 and Annexin V expression. Gli1CreERT2 x Slfn4 (fl/fl) mice were generated and infected with H. felis. Sildenafil was administered twice over 2 weeks by gavaging H. felis infected mice ~4 months after inoculation once SPEM had developed. RESULTS: Slfn4 was highly induced in both monocytic and granulocytic MDSCs from infected stomachs. Both Slfn4 (+)-MDSC populations exhibited strong transcriptional signatures for type-I interferon responsive GTPases and exhibited T cell suppressor function. SLFN4-containing protein complexes immunoprecipitated from myeloid cell cultures treated with IFNa exhibited GTPase activity. Knocking down Slfn4 or PDE5/6 inhibition with sildenafil blocked IFNa induction of GTP, SLFN4 and NOS2. Moreover, IFNa induction of Slfn (+)-MDSC function was inhibited by inducing their reactive oxygen species (ROS) production and apoptosis through protein kinase G activation. Accordingly, in vivo disruption of Slfn4 in Gli1CreERT2 x Slfn4 (fl/fl) mice or pharmacologic inhibition by sildenafil after Helicobacter infection also suppressed SLFN4 and NOS2, reversed T cell suppression and mitigated SPEM development. CONCLUSION: Taken together, SLFN4 regulates the activity of the GTPase pathway in MDSCs and precludes these cells from succumbing to the massive ROS generation when they acquire MDSC function.
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spelling pubmed-102726012023-06-17 Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases Ding, Lin Sheriff, Sulaiman Sontz, Ricky A. Merchant, Juanita L. Front Immunol Immunology INTRODUCTION: MDSCs express SCHLAFEN 4 (SLFN4) in Helicobacter-infected stomachs coincident with spasmolytic polypeptide-expressing metaplasia (SPEM), a precursor of gastric cancer. We aimed to characterize SLFN4(+) cell identity and the role of Slfn4 in these cells. METHODS: Single-cell RNA sequencing was performed on immune cells sorted from PBMCs and stomachs prepared from uninfected and 6-month H. felis-infected mice. Knockdown of Slfn4 by siRNA or PDE5/6 inhibition by sildenafil were performed in vitro. Intracellular ATP/GTP levels and GTPase activity of immunoprecipitated Slfn4 complexes were measured using the GTPase-Glo assay kit. The intracellular level of ROS was quantified by the DCF-DA fluorescent staining, and apoptosis was determined by cleaved Caspase-3 and Annexin V expression. Gli1CreERT2 x Slfn4 (fl/fl) mice were generated and infected with H. felis. Sildenafil was administered twice over 2 weeks by gavaging H. felis infected mice ~4 months after inoculation once SPEM had developed. RESULTS: Slfn4 was highly induced in both monocytic and granulocytic MDSCs from infected stomachs. Both Slfn4 (+)-MDSC populations exhibited strong transcriptional signatures for type-I interferon responsive GTPases and exhibited T cell suppressor function. SLFN4-containing protein complexes immunoprecipitated from myeloid cell cultures treated with IFNa exhibited GTPase activity. Knocking down Slfn4 or PDE5/6 inhibition with sildenafil blocked IFNa induction of GTP, SLFN4 and NOS2. Moreover, IFNa induction of Slfn (+)-MDSC function was inhibited by inducing their reactive oxygen species (ROS) production and apoptosis through protein kinase G activation. Accordingly, in vivo disruption of Slfn4 in Gli1CreERT2 x Slfn4 (fl/fl) mice or pharmacologic inhibition by sildenafil after Helicobacter infection also suppressed SLFN4 and NOS2, reversed T cell suppression and mitigated SPEM development. CONCLUSION: Taken together, SLFN4 regulates the activity of the GTPase pathway in MDSCs and precludes these cells from succumbing to the massive ROS generation when they acquire MDSC function. Frontiers Media S.A. 2023-06-02 /pmc/articles/PMC10272601/ /pubmed/37334372 http://dx.doi.org/10.3389/fimmu.2023.1139391 Text en Copyright © 2023 Ding, Sheriff, Sontz and Merchant https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Immunology
Ding, Lin
Sheriff, Sulaiman
Sontz, Ricky A.
Merchant, Juanita L.
Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases
title Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases
title_full Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases
title_fullStr Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases
title_full_unstemmed Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases
title_short Schlafen4(+)-MDSC in Helicobacter-induced gastric metaplasia reveals role for GTPases
title_sort schlafen4(+)-mdsc in helicobacter-induced gastric metaplasia reveals role for gtpases
topic Immunology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10272601/
https://www.ncbi.nlm.nih.gov/pubmed/37334372
http://dx.doi.org/10.3389/fimmu.2023.1139391
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