Departmental Papers (Dental)
Document Type
Journal Article
Date of this Version
1-2020
Publication Source
Pathogens
Volume
9
Issue
1
DOI
10.3390/pathogens9010038
Abstract
The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces lymphocytes to undergo cell-cycle arrest and apoptosis; toxicity is dependent upon the active Cdt subunit, CdtB. We now demonstrate that p21CIP1/WAF1 is critical to Cdt-induced apoptosis. Cdt induces increases in the levels of p21CIP1/WAF1 in lymphoid cell lines, Jurkat and MyLa, and in primary human lymphocytes. These increases were dependent upon CdtB’s ability to function as a phosphatidylinositol (PI) 3,4,5-triphosphate (PIP3) phosphatase. It is noteworthy that Cdt-induced increases in the levels of p21CIP1/WAF1 were accompanied by a significant decline in the levels of phosphorylated p21CIP1/WAF1. The significance of Cdt-induced p21CIP1/WAF1 increase was assessed by preventing these changes with a two-pronged approach; pre-incubation with the novel p21CIP1/WAF1 inhibitor, UC2288, and development of a p21CIP1/WAF1-deficient cell line (Jurkatp21−) using clustered regularly interspaced short palindromic repeats (CRISPR)/cas9 gene editing. UC2288 blocked toxininduced increases in p21CIP1/WAF1, and JurkatWT cells treated with this inhibitor exhibited reduced suscepstibility to Cdt-induced apoptosis. Likewise, Jurkatp21− cells failed to undergo toxin-induced apoptosis. The linkage between Cdt, p21CIP1/WAF1, and apoptosis was further established by demonstrating that Cdt-induced increases in levels of the pro-apoptotic proteins Bid, Bax, and Bak were dependent upon p21CIP1/WAF1 as these changes were not observed in Jurkatp21− cells. Finally, we determined that the p21CIP1/WAF1 increases were dependent upon toxin-induced increases in the level and activity of the chaperone heat shock protein (HSP) 90. We propose that p21CIP1/WAF1 plays a key pro-apoptotic role in mediating Cdt-induced toxicity. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
Aggregatibacter actinomycetemcomitans; Apoptosis; Cytolethal distending toxin; Lymphocytes; Virulence
Recommended Citation
Shenker, B. J., Walker, L. M., Zekavat, A., Weiss, R. H., & Boesze-Battaglia, K. (2020). The Cell-Cycle Regulatory Protein P21cip1/Waf1 is Required for Cytolethal Distending Toxin (Cdt)-Induced Apoptosis. Pathogens, 9 (1), http://dx.doi.org/10.3390/pathogens9010038
Date Posted: 08 December 2022
This document has been peer reviewed.