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Xiong Y, Luo J, Hong ZY, Zhu WZ, Hu A, Song BL. Hyperactivation of SREBP induces pannexin-1-dependent lytic cell death. J Lipid Res 2024; 65:100579. [PMID: 38880128 PMCID: PMC11284708 DOI: 10.1016/j.jlr.2024.100579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/06/2024] [Accepted: 06/09/2024] [Indexed: 06/18/2024] Open
Abstract
Sterol-regulatory element binding proteins (SREBPs) are a conserved transcription factor family governing lipid metabolism. When cellular cholesterol level is low, SREBP2 is transported from the endoplasmic reticulum to the Golgi apparatus where it undergoes proteolytic activation to generate a soluble N-terminal fragment, which drives the expression of lipid biosynthetic genes. Malfunctional SREBP activation is associated with various metabolic abnormalities. In this study, we find that overexpression of the active nuclear form SREBP2 (nSREBP2) causes caspase-dependent lytic cell death in various types of cells. These cells display typical pyroptotic and necrotic signatures, including plasma membrane ballooning and release of cellular contents. However, this phenotype is independent of the gasdermin family proteins or mixed lineage kinase domain-like (MLKL). Transcriptomic analysis identifies that nSREBP2 induces expression of p73, which further activates caspases. Through whole-genome CRISPR-Cas9 screening, we find that Pannexin-1 (PANX1) acts downstream of caspases to promote membrane rupture. Caspase-3 or 7 cleaves PANX1 at the C-terminal tail and increases permeability. Inhibition of the pore-forming activity of PANX1 alleviates lytic cell death. PANX1 can mediate gasdermins and MLKL-independent cell lysis during TNF-induced or chemotherapeutic reagents (doxorubicin or cisplatin)-induced cell death. Together, this study uncovers a noncanonical function of SREBPs as a potentiator of programmed cell death and suggests that PANX1 can directly promote lytic cell death independent of gasdermins and MLKL.
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Affiliation(s)
- Yanni Xiong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Zi-Yun Hong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Wen-Zhuo Zhu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Ao Hu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan, China.
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Griffiths G, Gruenberg J, Marsh M, Wohlmann J, Jones AT, Parton RG. Nanoparticle entry into cells; the cell biology weak link. Adv Drug Deliv Rev 2022; 188:114403. [PMID: 35777667 DOI: 10.1016/j.addr.2022.114403] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 12/22/2022]
Abstract
Nanoparticles (NP) are attractive options for the therapeutic delivery of active pharmaceutical drugs, proteins and nucleic acids into cells, tissues and organs. Research into the development and application of NP most often starts with a diverse group of scientists, including chemists, bioengineers and material and pharmaceutical scientists, who design, fabricate and characterize NP in vitro (Stage 1). The next step (Stage 2) generally investigates cell toxicity as well as the processes by which NP bind, are internalized and deliver their cargo to appropriate model tissue culture cells. Subsequently, in Stage 3, selected NP are tested in animal systems, mostly mouse. Whereas the chemistry-based development and analysis in Stage 1 is increasingly sophisticated, the investigations in Stage 2 are not what could be regarded as 'state-of-the-art' for the cell biology field and the quality of research into NP interactions with cells is often sub-standard. In this review we describe our current understanding of the mechanisms by which particles gain entry into mammalian cells via endocytosis. We summarize the most important areas for concern, highlight some of the most common mis-conceptions, and identify areas where NP scientists could engage with trained cell biologists. Our survey of the different mechanisms of uptake into cells makes us suspect that claims for roles for caveolae, as well as macropinocytosis, in NP uptake into cells have been exaggerated, whereas phagocytosis has been under-appreciated.
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Affiliation(s)
- Gareth Griffiths
- Department Biosciences, University of Oslo, Blindernveien 31, PO Box 1041, 0316 Oslo, Norway.
| | - Jean Gruenberg
- Department of Biochemistry, University of Geneva, 30 quai E. Ansermet, 1211-Geneva-4, Switzerland
| | - Mark Marsh
- Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jens Wohlmann
- Department Biosciences, University of Oslo, Blindernveien 31, PO Box 1041, 0316 Oslo, Norway
| | - Arwyn T Jones
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF103NB, UK
| | - Robert G Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, The University of Queensland, Qld 4072, Australia
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Chen L, Ma MY, Sun M, Jiang LY, Zhao XT, Fang XX, Man Lam S, Shui GH, Luo J, Shi XJ, Song BL. Endogenous sterol intermediates of the mevalonate pathway regulate HMGCR degradation and SREBP-2 processing. J Lipid Res 2019; 60:1765-1775. [PMID: 31455613 DOI: 10.1194/jlr.ra119000201] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/21/2019] [Indexed: 11/20/2022] Open
Abstract
Sterol-regulated HMG-CoA reductase (HMGCR) degradation and SREBP-2 cleavage are two major feedback regulatory mechanisms governing cholesterol biosynthesis. Reportedly, lanosterol selectively stimulates HMGCR degradation, and cholesterol is a specific regulator of SREBP-2 cleavage. However, it is unclear whether other endogenously generated sterols regulate these events. Here, we investigated the sterol intermediates from the mevalonate pathway of cholesterol biosynthesis using a CRISPR/Cas9-mediated genetic engineering approach. With a constructed HeLa cell line expressing the mevalonate transporter, we individually deleted genes encoding major enzymes in the mevalonate pathway, used lipidomics to measure sterol intermediates, and examined HMGCR and SREBP-2 statuses. We found that the C4-dimethylated sterol intermediates, including lanosterol, 24,25-dihydrolanosterol, follicular fluid meiosis activating sterol, testis meiosis activating sterol, and dihydro-testis meiosis activating sterol, were significantly upregulated upon mevalonate loading. These intermediates augmented both degradation of HMGCR and inhibition of SREBP-2 cleavage. The accumulated lanosterol induced rapid degradation of HMGCR, but did not inhibit SREBP-2 cleavage. The newly synthesized cholesterol from the mevalonate pathway is dispensable for inhibiting SREBP-2 cleavage. Together, these results suggest that lanosterol is a bona fide endogenous regulator that specifically promotes HMGCR degradation, and that other C4-dimethylated sterol intermediates may regulate both HMGCR degradation and SREBP-2 cleavage.
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Affiliation(s)
- Liang Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Mei-Yan Ma
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ming Sun
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Lu-Yi Jiang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xue-Tong Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xian-Xiu Fang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology , Chinese Academy of Sciences, Beijing 100101, China
| | - Guang-Hou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology , Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiong-Jie Shi
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
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Jeong A, Suazo KF, Wood WG, Distefano MD, Li L. Isoprenoids and protein prenylation: implications in the pathogenesis and therapeutic intervention of Alzheimer's disease. Crit Rev Biochem Mol Biol 2018; 53:279-310. [PMID: 29718780 PMCID: PMC6101676 DOI: 10.1080/10409238.2018.1458070] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The mevalonate-isoprenoid-cholesterol biosynthesis pathway plays a key role in human health and disease. The importance of this pathway is underscored by the discovery that two major isoprenoids, farnesyl and geranylgeranyl pyrophosphate, are required to modify an array of proteins through a process known as protein prenylation, catalyzed by prenyltransferases. The lipophilic prenyl group facilitates the anchoring of proteins in cell membranes, mediating protein-protein interactions and signal transduction. Numerous essential intracellular proteins undergo prenylation, including most members of the small GTPase superfamily as well as heterotrimeric G proteins and nuclear lamins, and are involved in regulating a plethora of cellular processes and functions. Dysregulation of isoprenoids and protein prenylation is implicated in various disorders, including cardiovascular and cerebrovascular diseases, cancers, bone diseases, infectious diseases, progeria, and neurodegenerative diseases including Alzheimer's disease (AD). Therefore, isoprenoids and/or prenyltransferases have emerged as attractive targets for developing therapeutic agents. Here, we provide a general overview of isoprenoid synthesis, the process of protein prenylation and the complexity of prenylated proteins, and pharmacological agents that regulate isoprenoids and protein prenylation. Recent findings that connect isoprenoids/protein prenylation with AD are summarized and potential applications of new prenylomic technologies for uncovering the role of prenylated proteins in the pathogenesis of AD are discussed.
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Affiliation(s)
- Angela Jeong
- Departments of Experimental and Clinical Pharmacolog,University of Minnesota, Minneapolis, MN 55455
| | | | - W. Gibson Wood
- Departments of Pharmacology, University of Minnesota, Minneapolis, MN 55455
| | - Mark D. Distefano
- Departments of Chemistry,University of Minnesota, Minneapolis, MN 55455
| | - Ling Li
- Departments of Experimental and Clinical Pharmacolog,University of Minnesota, Minneapolis, MN 55455
- Departments of Pharmacology, University of Minnesota, Minneapolis, MN 55455
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Torday JS. Pleiotropy as the Mechanism for Evolving Novelty: Same Signal, Different Result. BIOLOGY 2015; 4:443-59. [PMID: 26103090 PMCID: PMC4498309 DOI: 10.3390/biology4020443] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/02/2015] [Accepted: 06/10/2015] [Indexed: 11/22/2022]
Abstract
In contrast to the probabilistic way of thinking about pleiotropy as the random expression of a single gene that generates two or more distinct phenotypic traits, it is actually a deterministic consequence of the evolution of complex physiology from the unicellular state. Pleiotropic novelties emerge through recombinations and permutations of cell-cell signaling exercised during reproduction based on both past and present physical and physiologic conditions, in service to the future needs of the organism for its continued survival. Functional homologies ranging from the lung to the kidney, skin, brain, thyroid and pituitary exemplify the evolutionary mechanistic strategy of pleiotropy. The power of this perspective is exemplified by the resolution of evolutionary gradualism and punctuated equilibrium in much the same way that Niels Bohr resolved the paradoxical duality of light as Complementarity.
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Affiliation(s)
- John S Torday
- Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA 90502-2006, USA.
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Bissig C, Gruenberg J. ALIX and the multivesicular endosome: ALIX in Wonderland. Trends Cell Biol 2014; 24:19-25. [DOI: 10.1016/j.tcb.2013.10.009] [Citation(s) in RCA: 216] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/29/2013] [Accepted: 10/30/2013] [Indexed: 01/19/2023]
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