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The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity

Human lymphocytes exposed to Aggregatibacter actinomycetemcomitans (Aa) cytolethal distending toxin (Cdt) undergo cell cycle arrest and apoptosis. In previous studies, we demonstrated that the active Cdt subunit, CdtB, is a potent phosphatidylinositol (PI) 3,4,5-triphosphate phosphatase. Moreover, A...

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Autores principales: Huang, Grace, Boesze-Battaglia, Kathleen, Walker, Lisa P., Zekavat, Ali, Schaefer, Zachary P., Blanke, Steven R., Shenker, Bruce J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039388/
https://www.ncbi.nlm.nih.gov/pubmed/33854985
http://dx.doi.org/10.3389/fcimb.2021.664221
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author Huang, Grace
Boesze-Battaglia, Kathleen
Walker, Lisa P.
Zekavat, Ali
Schaefer, Zachary P.
Blanke, Steven R.
Shenker, Bruce J.
author_facet Huang, Grace
Boesze-Battaglia, Kathleen
Walker, Lisa P.
Zekavat, Ali
Schaefer, Zachary P.
Blanke, Steven R.
Shenker, Bruce J.
author_sort Huang, Grace
collection PubMed
description Human lymphocytes exposed to Aggregatibacter actinomycetemcomitans (Aa) cytolethal distending toxin (Cdt) undergo cell cycle arrest and apoptosis. In previous studies, we demonstrated that the active Cdt subunit, CdtB, is a potent phosphatidylinositol (PI) 3,4,5-triphosphate phosphatase. Moreover, AaCdt-treated cells exhibit evidence of PI-3-kinase (PI-3K) signaling blockade characterized by reduced levels of PIP3, pAkt, and pGSK3β. We have also demonstrated that PI-3K blockade is a requisite of AaCdt-induced toxicity in lymphocytes. In this study, we extended our observations to include assessment of Cdts from Haemophilus ducreyi (HdCdt) and Campylobacter jejuni (CjCdt). We now report that the CdtB subunit from HdCdt and CjCdt, similar to that of AaCdt, exhibit potent PIP3 phosphatase activity and that Jurkat cells treated with these Cdts exhibit PI-3K signaling blockade: reduced levels of pAkt and pGSK3β. Since non-phosphorylated GSK3β is the active form of this kinase, we compared Cdts for dependence on GSK3β activity. Two GSK3β inhibitors were employed, LY2090314 and CHIR99021; both inhibitors blocked the ability of Cdts to induce cell cycle arrest. We have previously demonstrated that AaCdt induces increases in the CDK inhibitor, p21(CIP1/WAF1), and, further, that this was a requisite for toxin-induced cell death via apoptosis. We now demonstrate that HdCdt and CjCdt also share this requirement. It is also noteworthy that p21(CIP1/WAF1) was not involved in the ability of the three Cdts to induce cell cycle arrest. Finally, we demonstrate that, like AaCdt, HdCdt is dependent upon the host cell protein, cellugyrin, for its toxicity (and presumably internalization of CdtB); CjCdt was not dependent upon this protein. The implications of these findings as they relate to Cdt’s molecular mode of action are discussed.
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spelling pubmed-80393882021-04-13 The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity Huang, Grace Boesze-Battaglia, Kathleen Walker, Lisa P. Zekavat, Ali Schaefer, Zachary P. Blanke, Steven R. Shenker, Bruce J. Front Cell Infect Microbiol Cellular and Infection Microbiology Human lymphocytes exposed to Aggregatibacter actinomycetemcomitans (Aa) cytolethal distending toxin (Cdt) undergo cell cycle arrest and apoptosis. In previous studies, we demonstrated that the active Cdt subunit, CdtB, is a potent phosphatidylinositol (PI) 3,4,5-triphosphate phosphatase. Moreover, AaCdt-treated cells exhibit evidence of PI-3-kinase (PI-3K) signaling blockade characterized by reduced levels of PIP3, pAkt, and pGSK3β. We have also demonstrated that PI-3K blockade is a requisite of AaCdt-induced toxicity in lymphocytes. In this study, we extended our observations to include assessment of Cdts from Haemophilus ducreyi (HdCdt) and Campylobacter jejuni (CjCdt). We now report that the CdtB subunit from HdCdt and CjCdt, similar to that of AaCdt, exhibit potent PIP3 phosphatase activity and that Jurkat cells treated with these Cdts exhibit PI-3K signaling blockade: reduced levels of pAkt and pGSK3β. Since non-phosphorylated GSK3β is the active form of this kinase, we compared Cdts for dependence on GSK3β activity. Two GSK3β inhibitors were employed, LY2090314 and CHIR99021; both inhibitors blocked the ability of Cdts to induce cell cycle arrest. We have previously demonstrated that AaCdt induces increases in the CDK inhibitor, p21(CIP1/WAF1), and, further, that this was a requisite for toxin-induced cell death via apoptosis. We now demonstrate that HdCdt and CjCdt also share this requirement. It is also noteworthy that p21(CIP1/WAF1) was not involved in the ability of the three Cdts to induce cell cycle arrest. Finally, we demonstrate that, like AaCdt, HdCdt is dependent upon the host cell protein, cellugyrin, for its toxicity (and presumably internalization of CdtB); CjCdt was not dependent upon this protein. The implications of these findings as they relate to Cdt’s molecular mode of action are discussed. Frontiers Media S.A. 2021-03-29 /pmc/articles/PMC8039388/ /pubmed/33854985 http://dx.doi.org/10.3389/fcimb.2021.664221 Text en Copyright © 2021 Huang, Boesze-Battaglia, Walker, Zekavat, Schaefer, Blanke and Shenker 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 Cellular and Infection Microbiology
Huang, Grace
Boesze-Battaglia, Kathleen
Walker, Lisa P.
Zekavat, Ali
Schaefer, Zachary P.
Blanke, Steven R.
Shenker, Bruce J.
The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity
title The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity
title_full The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity
title_fullStr The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity
title_full_unstemmed The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity
title_short The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity
title_sort active subunit of the cytolethal distending toxin, cdtb, derived from both haemophilus ducreyi and campylobacter jejuni exhibits potent phosphatidylinositol-3,4,5-triphosphate phosphatase activity
topic Cellular and Infection Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039388/
https://www.ncbi.nlm.nih.gov/pubmed/33854985
http://dx.doi.org/10.3389/fcimb.2021.664221
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