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https://doi.org/10.1038/cdd.2014.54
Title: | Ubiquitination by SAG regulates macrophage survival/death and immune response during infection | Authors: | Chang, SC Ding, JL |
Keywords: | Animals Carrier Proteins Cell Death Cell Line Cell Survival Macrophages Mice Pseudomonas Infections Pseudomonas aeruginosa Ubiquitination |
Issue Date: | Sep-2014 | Publisher: | Springer Science and Business Media LLC | Citation: | Chang, SC, Ding, JL (2014-09). Ubiquitination by SAG regulates macrophage survival/death and immune response during infection. CELL DEATH AND DIFFERENTIATION 21 (9) : 1388-1398. ScholarBank@NUS Repository. https://doi.org/10.1038/cdd.2014.54 | Abstract: | The checkpoint between the life and death of macrophages is crucial for the host's frontline immune defense during acute phase infection. However, the mechanism as to how the immune cell equilibrates between apoptosis and immune response is unclear. Using in vitro and ex vivo approaches, we showed that macrophage survival is synchronized by SAG (sensitive to apoptosis gene), which is a key member of the ubiquitin-proteasome system (UPS). When challenged by pathogen-associated molecular patterns (PAMPs), we observed a reciprocal expression profile of pro- and antiapoptotic factors in macrophages. However, SAG knockdown disrupted this balance. Further analysis revealed that ubiquitination of Bax and SARM (sterile α- and HEAT/armadillo-motif- containing protein) by SAG-UPS confers survival advantage to infected macrophages. SAG knockdown caused the accumulation of proapoptotic Bax and SARM, imbalance of Bcl-2/Bax in the mitochondria, induction of cytosolic cytochrome c and activation of caspase-9 and -3, all of which led to disequilibrium between life and death of macrophages. In contrast, SAG-overexpressing macrophages challenged with PAMPs exhibited upregulation of protumorigenic cytokines (IL-1β, IL-6 and TNF-α), and downregulation of antitumorigenic cytokine (IL-12p40) and anti-inflammatory cytokine (IL-10). This suggests that SAG-dependent UPS is a key switch between immune defense and apoptosis or immune overactivation and tumorigenesis. Altogether, our results indicate that SAG-UPS facilitates a timely and appropriate level of immune response, prompting future development of potential immunomodulators of SAG-UPS. © 2014 Macmillan Publishers Limited All rights reserved. | Source Title: | CELL DEATH AND DIFFERENTIATION | URI: | https://scholarbank.nus.edu.sg/handle/10635/234930 | ISSN: | 1350-9047 1476-5403 |
DOI: | 10.1038/cdd.2014.54 |
Appears in Collections: | Staff Publications Elements |
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