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Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells
Proteins of the BCL-2 family are evolutionarily conserved modulators of apoptosis that function as sensors of cellular integrity. Over the past three decades multiple BCL-2 family members have been identified, many of which are now fully incorporated into regulatory networks governing the mitochondr...
Autores principales: | , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985252/ https://www.ncbi.nlm.nih.gov/pubmed/31988296 http://dx.doi.org/10.1038/s41419-020-2263-0 |
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author | Woznicki, Jerzy A. Flood, Peter Bustamante-Garrido, Milan Stamou, Panagiota Moloney, Gerry Fanning, Aine Zulquernain, Syed Akbar McCarthy, Jane Shanahan, Fergus Melgar, Silvia Nally, Ken |
author_facet | Woznicki, Jerzy A. Flood, Peter Bustamante-Garrido, Milan Stamou, Panagiota Moloney, Gerry Fanning, Aine Zulquernain, Syed Akbar McCarthy, Jane Shanahan, Fergus Melgar, Silvia Nally, Ken |
author_sort | Woznicki, Jerzy A. |
collection | PubMed |
description | Proteins of the BCL-2 family are evolutionarily conserved modulators of apoptosis that function as sensors of cellular integrity. Over the past three decades multiple BCL-2 family members have been identified, many of which are now fully incorporated into regulatory networks governing the mitochondrial apoptotic pathway. For some, however, an exact role in cell death signalling remains unclear. One such ‘orphan’ BCL-2 family member is BCL-G (or BCL2L14). In this study we analysed gastrointestinal expression of human BCL-G in health and disease states, and investigated its contribution to inflammation-induced tissue damage by exposing intestinal epithelial cells (IEC) to IFN-γ and TNF-α, two pro-inflammatory mediators associated with gut immunopathology. We found that both BCL-G splice variants — BCL-G(S) (short) and BCL-G(L) (long) — were highly expressed in healthy gut tissue, and that their mRNA levels decreased in active inflammatory bowel diseases (for BCL-G(S)) and colorectal cancer (for BCL-G(S/L)). In vitro studies revealed that IFN-γ and TNF-α synergised to upregulate BCL-G(S/L) and to trigger apoptosis in colonic epithelial cell lines and primary human colonic organoids. Using RNAi, we showed that synergistic induction of IEC death was STAT1-dependent while optimal expression of BCL-G(S/L) required STAT1, NF-κB/p65 and SWI/SNF-associated chromatin remodellers BRM and BRG1. To test the direct contribution of BCL-G to the effects of IFN-γ and TNF-α on epithelial cells, we used RNAi- and CRISPR/Cas9-based perturbations in parallel with isoform-specific overexpression of BCL-G, and found that BCL-G was dispensable for Th1 cytokine-induced apoptosis of human IEC. Instead, we discovered that depletion of BCL-G differentially affected secretion of inflammatory chemokines CCL5 and CCL20, thus uncovering a non-apoptotic immunoregulatory function of this BCL-2 family member. Taken together, our data indicate that BCL-G may be involved in shaping immune responses in the human gut in health and disease states through regulation of chemokine secretion rather than intestinal apoptosis. |
format | Online Article Text |
id | pubmed-6985252 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-69852522020-01-28 Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells Woznicki, Jerzy A. Flood, Peter Bustamante-Garrido, Milan Stamou, Panagiota Moloney, Gerry Fanning, Aine Zulquernain, Syed Akbar McCarthy, Jane Shanahan, Fergus Melgar, Silvia Nally, Ken Cell Death Dis Article Proteins of the BCL-2 family are evolutionarily conserved modulators of apoptosis that function as sensors of cellular integrity. Over the past three decades multiple BCL-2 family members have been identified, many of which are now fully incorporated into regulatory networks governing the mitochondrial apoptotic pathway. For some, however, an exact role in cell death signalling remains unclear. One such ‘orphan’ BCL-2 family member is BCL-G (or BCL2L14). In this study we analysed gastrointestinal expression of human BCL-G in health and disease states, and investigated its contribution to inflammation-induced tissue damage by exposing intestinal epithelial cells (IEC) to IFN-γ and TNF-α, two pro-inflammatory mediators associated with gut immunopathology. We found that both BCL-G splice variants — BCL-G(S) (short) and BCL-G(L) (long) — were highly expressed in healthy gut tissue, and that their mRNA levels decreased in active inflammatory bowel diseases (for BCL-G(S)) and colorectal cancer (for BCL-G(S/L)). In vitro studies revealed that IFN-γ and TNF-α synergised to upregulate BCL-G(S/L) and to trigger apoptosis in colonic epithelial cell lines and primary human colonic organoids. Using RNAi, we showed that synergistic induction of IEC death was STAT1-dependent while optimal expression of BCL-G(S/L) required STAT1, NF-κB/p65 and SWI/SNF-associated chromatin remodellers BRM and BRG1. To test the direct contribution of BCL-G to the effects of IFN-γ and TNF-α on epithelial cells, we used RNAi- and CRISPR/Cas9-based perturbations in parallel with isoform-specific overexpression of BCL-G, and found that BCL-G was dispensable for Th1 cytokine-induced apoptosis of human IEC. Instead, we discovered that depletion of BCL-G differentially affected secretion of inflammatory chemokines CCL5 and CCL20, thus uncovering a non-apoptotic immunoregulatory function of this BCL-2 family member. Taken together, our data indicate that BCL-G may be involved in shaping immune responses in the human gut in health and disease states through regulation of chemokine secretion rather than intestinal apoptosis. Nature Publishing Group UK 2020-01-27 /pmc/articles/PMC6985252/ /pubmed/31988296 http://dx.doi.org/10.1038/s41419-020-2263-0 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Article Woznicki, Jerzy A. Flood, Peter Bustamante-Garrido, Milan Stamou, Panagiota Moloney, Gerry Fanning, Aine Zulquernain, Syed Akbar McCarthy, Jane Shanahan, Fergus Melgar, Silvia Nally, Ken Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells |
title | Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells |
title_full | Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells |
title_fullStr | Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells |
title_full_unstemmed | Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells |
title_short | Human BCL-G regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by IFN-γ and TNF-α in intestinal epithelial cells |
title_sort | human bcl-g regulates secretion of inflammatory chemokines but is dispensable for induction of apoptosis by ifn-γ and tnf-α in intestinal epithelial cells |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985252/ https://www.ncbi.nlm.nih.gov/pubmed/31988296 http://dx.doi.org/10.1038/s41419-020-2263-0 |
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