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Hu LL, Zou K, Chen Y, Wu LJ, Cao J, Xiong XY, Wang L, Cheng XS, Xiao QZ, Yang RQ. Functional role and molecular mechanisms underlying prohibitin 2 in platelet mitophagy and activation. Mol Med Rep 2021; 23:384. [PMID: 33760146 PMCID: PMC7986013 DOI: 10.3892/mmr.2021.12023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/24/2021] [Indexed: 12/20/2022] Open
Abstract
Platelet mitophagy is a major pathway involved in the clearance of injured mitochondria during hemostasis and thrombosis. Prohibitin 2 (PHB2) has recently emerged as an inner mitochondrial membrane receptor involved in mitophagy. However, the mechanisms underlying PHB2-mediated platelet mitophagy and activation are not completely understood. PHB2 is a highly conserved inner mitochondrial membrane protein that regulates mitochondrial assembly and function due to its unique localization on the mitochondrial membrane. The present study aimed to investigate the role and mechanism underlying PHB2 in platelet mitophagy and activation. Phorbol-12-myristate-13-acetate (PMA) was used to induce MEG-01 cells maturation and differentiate into platelets following PHB2 knockdown. Cell Counting Kit-8 assays were performed to examine platelet viability. Flow cytometry was performed to assess platelet mitochondrial membrane potential. RT-qPCR and western blotting were conducted to measure mRNA and protein expression levels, respectively. Subsequently, platelets were exposed to CCCP and the role of PHB2 was assessed. The results of the present study identified a crucial role for PHB2 in platelet mitophagy and activation, suggesting that PHB2-mediated regulation of mitophagy may serve as a novel strategy for downregulating the expression of platelet activation genes. Although further research into mitophagy is required, the present study suggested that PHB2 may serve as a novel therapeutic target for thrombosis-related diseases due to its unique localization on the mitochondrial membrane.
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Affiliation(s)
- Long-Long Hu
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Kai Zou
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Yuan Chen
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Li-Juan Wu
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Jie Cao
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Xiao-Ying Xiong
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Ling Wang
- Medicine Lab, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Xiao-Shu Cheng
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Qing-Zhong Xiao
- Department of Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Ren-Qiang Yang
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
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Luo XL, Jiang JY, Huang Z, Chen LX. Autophagic regulation of platelet biology. J Cell Physiol 2019; 234:14483-14488. [PMID: 30714132 DOI: 10.1002/jcp.28243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/25/2018] [Accepted: 01/10/2019] [Indexed: 01/24/2023]
Abstract
Platelets, developed from megakaryocytes, are characterized by anucleate and short-life span hemocyte in mammal vessel. Platelets are very important in the cardiovascular system. Studies indicate the occurrence of autophagy platelets and megakaryocytes. Moreover, abnormal autophagy decreases the number of platelets and suppresses platelet aggregation. In addition, mitophagy, as a kind of selective autophagy, could inhibit platelet aggregation under oxidative stress or hypoxic, whereas promote platelet aggregation after reperfusion. Finally, autophagy regulates hemorrhagic and thrombosis diseases by influencing the number and function of platelets. In this paper, the role of autophagy in platelets and megakaryocytes, as well as coupled with the promotive or inhibitory role of hemorrhagic and thrombosis diseases are elucidated. Therefore, autophagy may be a potentially therapeutic target in modulating the platelet-related diseases.
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Affiliation(s)
- Xu-Ling Luo
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Jin-Yong Jiang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Zhen Huang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Lin-Xi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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Banerjee M, Huang Y, Ouseph MM, Joshi S, Pokrovskaya I, Storrie B, Zhang J, Whiteheart SW, Wang QJ. Autophagy in Platelets. Methods Mol Biol 2019; 1880:511-528. [PMID: 30610718 DOI: 10.1007/978-1-4939-8873-0_32] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Anucleate platelets are produced by fragmentation of megakaryocytes. Platelets circulate in the bloodstream for a finite period: upon vessel injury, they are activated to participate in hemostasis; upon senescence, unused platelets are cleared. Platelet hypofunction leads to bleeding. Conversely, pathogenic platelet activation leads to occlusive events that precipitate strokes and heart attacks. Recently, we and others have shown that autophagy occurs in platelets and is important for platelet production and normal functions including hemostasis and thrombosis. Due to the unique properties of platelets, such as their lack of nuclei and their propensity for activation, methods for studying platelet autophagy must be specifically tailored. Here, we describe useful methods for examining autophagy in both human and mouse platelets.
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Affiliation(s)
- Meenakshi Banerjee
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Yunjie Huang
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Madhu M Ouseph
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Smita Joshi
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Irina Pokrovskaya
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Brian Storrie
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jinchao Zhang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Sidney W Whiteheart
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Qing Jun Wang
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY, USA.
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Abstract
Autophagy is important for maintaining cellular homeostasis, and thus its deficiency is implicated in a broad spectrum of human diseases. Its role in platelet function has only recently been examined. Our biochemical and imaging studies demonstrate that the core autophagy machinery exists in platelets, and that autophagy is constitutively active in resting platelets. Moreover, autophagy is induced upon platelet activation, as indicated by agonist-induced loss of the autophagy marker LC3II. Additional experiments, using inhibitors of platelet activation, proteases, and lysosomal acidification, as well as platelets from knockout mouse strains, show that agonist-induced LC3II loss is a consequence of platelet signaling cascades and requires proteases, acidic compartments, and membrane fusion. To assess the physiological role of platelet autophagy, we generated a mouse strain with a megakaryocyte- and platelet-specific deletion of Atg7, an enzyme required for LC3II production. Ex vivo analysis of platelets from these mice shows modest defects in aggregation and granule cargo packaging. Although these mice have normal platelet numbers and size distributions, they exhibit a robust bleeding diathesis in the tail-bleeding assay and a prolonged occlusion time in the FeCl3-induced carotid injury model. Our results demonstrate that autophagy occurs in platelets and is important for hemostasis and thrombosis.
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