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Gonzalez CD, Resnik R, Vaccaro MI. Secretory Autophagy and Its Relevance in Metabolic and Degenerative Disease. Front Endocrinol (Lausanne) 2020; 11:266. [PMID: 32477265 PMCID: PMC7232537 DOI: 10.3389/fendo.2020.00266] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 04/09/2020] [Indexed: 12/11/2022] Open
Abstract
Proteins to be secreted through so-called "conventional mechanisms" are characterized by the presence of an N-terminal peptide that is a leader or signal peptide, needed for access to the endoplasmic reticulum and the Golgi apparatus for further secretion. However, some relevant cytosolic proteins lack of this signal peptides and should be secreted by different unconventional or "non-canonical" processes. One form of this unconventional secretion was named secretory autophagy (SA) because it is specifically associated with the autophagy pathway. It is defined by ATG proteins that regulate the biogenesis of the autophagosome, its representative organelle. The canonical macroautophagy involves the fusion of the autophagosomes with lysosomes for content degradation, whereas the SA pathway bypasses this degradative process to allow the secretion. ATG5, as well as other factors involved in autophagy such as BCN1, are also activated as part of the secretory pathway. SA has been recognized as a new mechanism that is becoming of increasing relevance to explain the unconventional secretion of a series of cytosolic proteins that have critical biological importance. Also, SA may play a role in the release of aggregation-prone protein since it has been related to the autophagosome biogenesis machinery. SA requires the autophagic pathway and both, secretory autophagy and canonical degradative autophagy are at the same time, integrated and highly regulated processes that interact in ultimate cross-talking molecular mechanisms. The potential implications of alterations in SA, its cargos, pathways, and regulation in human diseases such as metabolic/aging pathological processes are predictable. Further research of SA as potential target of therapeutic intervention is deserved.
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Affiliation(s)
- Claudio Daniel Gonzalez
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
- CEMIC University Institute, Buenos Aires, Argentina
| | - Roxana Resnik
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
- CEMIC University Institute, Buenos Aires, Argentina
| | - Maria Ines Vaccaro
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
- CEMIC University Institute, Buenos Aires, Argentina
- *Correspondence: Maria Ines Vaccaro ;
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Zi Y, Yi-An Y, Bing J, Yan L, Jing T, Chun-Yu G, Fan P, Hao L, Jia-Ni T, Han-Jin H, Fei C, Xue-Bo L. Sirt6-induced autophagy restricted TREM-1-mediated pyroptosis in ox-LDL-treated endothelial cells: relevance to prognostication of patients with acute myocardial infarction. Cell Death Discov 2019; 5:88. [PMID: 30993014 PMCID: PMC6461678 DOI: 10.1038/s41420-019-0168-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/12/2019] [Accepted: 03/21/2019] [Indexed: 01/29/2023] Open
Abstract
Inflammation mediated by myeloid cells trigger receptors 1 (TREM-1) is important for atherosclerosis development, while sirtuin 6 (Sirt6) levels decrease in atheroscleoritc plaque. Here we demonstrate that oxidatively modified low density lipoprotein (ox-LDL)-treated endothelial cells (ECs) exhibited increased TREM-1-mediated pyroptosis and decreased Sirt6-induced autophagy. We show that high sTREM-1 and low sSirt6 levels were independent predictors of boosted endothelial microparticles (EMPs) on admission, and were associated with increased risk for all-cause mortality and major adverse cardiovascular events (MACE) at median 24 months (interquartile range, 18–26) follow-up in acute myocardial infarction (AMI) patients. Additionally, blockage of Sirt6-induced autophagy led to augmented TREM-1-mediated pyroptosis, whereas Sirt6 overexpression attenuated ECs inflammation and pyroptosis following ox-LDL treatment. Our findings indicate that TREM-1 and in a reversed trend Sirt6 appeared to be markers of endothelial inflammation with potential for use in risk stratification.
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Affiliation(s)
- Ye Zi
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Yao Yi-An
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Ji Bing
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Lai Yan
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Tong Jing
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Guan Chun-Yu
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Ping Fan
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Lin Hao
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Tang Jia-Ni
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Hou Han-Jin
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Chen Fei
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
| | - Liu Xue-Bo
- Department of Cardiology, Shanghai Tongji Hospital, Tongji University, Shanghai, China
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Cypryk W, Nyman TA, Matikainen S. From Inflammasome to Exosome-Does Extracellular Vesicle Secretion Constitute an Inflammasome-Dependent Immune Response? Front Immunol 2018; 9:2188. [PMID: 30319640 PMCID: PMC6167409 DOI: 10.3389/fimmu.2018.02188] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/04/2018] [Indexed: 12/11/2022] Open
Abstract
Inflammasomes are intracellular protein complexes of pattern recognition receptors and caspase-1, with essential functions in regulating inflammatory responses of macrophages and dendritic cells. The primary role of inflammasomes is to catalyze processing and secretion of pro-inflammatory cytokines IL-1β and IL-18. Recently, intracellular non-canonical inflammasome activation by caspases-4/5, which are also regulators of pyroptosis via processing gasdermin D, has been elucidated. Caspase-1, the effector protease of inflammasome complex, is also known to modulate secretion of large number of other proteins. Thereby, besides its known role in processing pro-inflammatory cytokines, the inflammasome turns into a universal regulator of protein secretion, which allows the danger-exposed cells to release various proteins in order to alert and guide neighboring cells. Majority of these proteins are not secreted through the conventional ER-Golgi secretory pathway. Instead, they are segregated in membrane-enclosed compartment and secreted in nanosized extracellular vesicles, which protect their cargo and guide it for delivery. Growing evidence indicates that inflammasome activity correlates with enhanced secretion of extracellular vesicles and modulation of their protein cargo. This inflammasome-driven unconventional, vesicle-mediated secretion of multitude of immunoregulatory proteins may constitute a novel paradigm in inflammatory responses. In this mini review we discuss the current knowledge and highlight unsolved questions about metabolic processes, signals, and mechanisms linking inflammasome activity with regulated extracellular vesicle secretion of proteins. Further investigations on this relationship may in the future help understanding the significance of extracellular vesicle secretion in inflammatory diseases such as atherosclerosis, gouty arthritis, asthma, Alzheimer's and many others.
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Affiliation(s)
- Wojciech Cypryk
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland
| | - Tuula A Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Rikshospitalet Oslo, Oslo, Norway
| | - Sampsa Matikainen
- Division of Rheumatology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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