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Nam LB, Kim SJ, Nguyen TK, Jeong CY, Lee JY, Lee JS, Seo JT, Moon SJ. Cholesterol sulfate as a negative regulator of cellular cholesterol homeostasis. Mol Cells 2025; 48:100209. [PMID: 40089157 DOI: 10.1016/j.mocell.2025.100209] [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: 11/25/2024] [Revised: 03/05/2025] [Accepted: 03/07/2025] [Indexed: 03/17/2025] Open
Abstract
Cholesterol sulfate (CS), one of the most abundant cholesterol derivatives, recently emerged as a key regulatory molecule in several physiological processes. Here, we demonstrate multiple mechanisms by which CS reduces intracellular cholesterol levels. CS promotes the proteasomal degradation of 3-hydroxy-3-methylglutaryl-CoA reductase reductase by enhancing insulin-induced gene-mediated ubiquitination, thereby inhibiting cholesterol synthesis. In addition, CS blocks low-density lipoprotein receptor endocytosis, reducing low-density lipoprotein cholesterol uptake. CS further suppresses the proteolytic activation of sterol regulatory element-binding protein 2, a master transcription factor governing cholesterol synthesis and uptake. Using in vitro and in vivo models, we show that CS lowers cholesterol by targeting both the cholesterol synthesis and uptake pathways, while also modulating an important feedback loop via sterol regulatory element-binding protein 2. These findings highlight the potential of CS as a modulator of cholesterol metabolism, offering new therapeutic insights into cholesterol-related disorders.
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Affiliation(s)
- Le Ba Nam
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - Sung-Jin Kim
- Department of Oral Histology and Developmental Biology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea
| | - Tan Khanh Nguyen
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - Chang-Yun Jeong
- Department of Microbiology, BK21 PLUS Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - June-Yong Lee
- Department of Microbiology, BK21 PLUS Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jun-Seok Lee
- Department of Pharmacology, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Jeong Taeg Seo
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - Seok Jun Moon
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul 03722, Korea.
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2
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Lee AK, Welander PV. A geranylgeranyl reductase homolog required for cholesterol production in Myxococcota. J Bacteriol 2025; 207:e0049524. [PMID: 40067012 PMCID: PMC12004948 DOI: 10.1128/jb.00495-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2024] [Accepted: 02/14/2025] [Indexed: 04/18/2025] Open
Abstract
Myxococcota is a phylum of sterol-producing bacteria. They exhibit a clade depth for sterol biosynthesis unparalleled in the bacterial domain and produce sterols of a biosynthetic complexity that rivals eukaryotes. Additionally, the sterol biosynthesis pathways found in this phylum have been proposed as a potential source for sterol biosynthesis in the last eukaryotic common ancestor, lending evolutionary importance to our understanding of this pathway in Myxococcota. However, sterol production has only been characterized in a few species, and outstanding questions about the evolutionary history of this pathway remain. Here, we identify two myxobacteria, Minicystis rosea and Sandaracinus amylolyticus, capable of cholesterol biosynthesis. These two myxobacteria possess a cholesterol biosynthesis pathway that differs in both the ordering and enzymes involved in biosynthesis compared with Enhygromyxa salina, a myxobacterium previously demonstrated to produce cholesterol, as well as the canonical pathways found in eukaryotes. We characterize an alternative bacterial reductase responsible for performing C-24 reduction, further delineating bacterial cholesterol production from eukaryotes. Finally, we examine the distribution and phylogenetic relationships of sterol biosynthesis proteins across both cultured and uncultured Myxococcota species, providing evidence for multiple acquisition events and instances of both horizontal and vertical transfer at the family level. Altogether, this work further demonstrates the capacity of myxobacteria to synthesize eukaryotic sterols but with an underlying diversity in the biochemical reactions that govern sterol synthesis, suggesting a complex evolutionary history and refining our understanding of how myxobacterial cholesterol production relates to their eukaryotic counterparts. IMPORTANCE Sterols are essential and ubiquitous lipids in eukaryotes, but their significance in bacteria is less understood. Sterol production in Myxococcota, a phylum of developmentally complex predatory bacteria, has provided insight into novel sterol biochemistry and prompted discussion regarding the evolution of this pathway within both the eukaryotic and bacterial domains. Here, we characterize cholesterol biosynthesis in two myxobacteria, providing evidence for distinct pathway organization and identifying a unique protein responsible for C-24 reduction. We couple these results with the phylogenomic analysis of sterol biosynthesis within Myxococcota, revealing a complicated evolutionary history marked by vertical and horizontal transfer. This suggests a mosaic acquisition of this pathway in Myxococcota and highlights the complex role myxobacteria may have had in sterol transfer to eukaryotes.
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Affiliation(s)
- Alysha K. Lee
- Department of Earth Systems Science, Stanford University, Stanford, California, USA
| | - Paula V. Welander
- Department of Earth Systems Science, Stanford University, Stanford, California, USA
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Yaeger JDW, Sengupta S, Walz AL, Morita M, Morgan TK, Vermeer PD, Francis KR. Cholesterol deficiency directs autophagy-dependent secretion of extracellular vesicles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.01.11.632510. [PMID: 39829772 PMCID: PMC11741461 DOI: 10.1101/2025.01.11.632510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/22/2025]
Abstract
Extracellular vesicle (EV) secretion is an important, though not fully understood, intercellular communication process. Lipid metabolism has been shown to regulate EV activity, though the impact of specific lipid classes is unclear. Through analysis of small EVs (sEVs), we observe aberrant increases in sEV release within genetic models of cholesterol biosynthesis disorders, where cellular cholesterol is diminished. Inhibition of cholesterol synthesis at multiple synthetic steps mimics genetic models in terms of cholesterol reduction and sEVs secreted. Further analyses of sEVs from cholesterol-depleted cells revealed structural deficits and altered surface marker expression, though these sEVs were also more easily internalized by recipient cells. Transmission electron microscopy of cells with impaired cholesterol biosynthesis demonstrated multivesicular and multilamellar structures potentially associated with autophagic defects. We further found autophagic vesicles being redirected toward late endosomes at the expense of autophagolysosomes. Through CRISPR-mediated inhibition of autophagosome formation, we mechanistically determined that release of sEVs after cholesterol depletion is autophagy dependent. We conclude that cholesterol imbalance initiates autophagosome-dependent secretion of sEVs, which may have pathological relevance in diseases of cholesterol disequilibrium.
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Affiliation(s)
- Jazmine D. W. Yaeger
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Sonali Sengupta
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Austin L. Walz
- Cancer Biology and Immunotherapies Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Mayu Morita
- Department of Pathology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Terry K. Morgan
- Department of Pathology, Oregon Health & Science University, Portland, OR 97239, USA
- Center for Developmental Health, Oregon Health and Science University, Portland, OR 97239, USA
| | - Paola D. Vermeer
- Cancer Biology and Immunotherapies Group, Sanford Research, Sioux Falls, SD 57104, USA
- Department of Surgery, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA
| | - Kevin R. Francis
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA
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Lapshin NK, Piotrovskii MS, Trofimova MS. How sterols affect protoplasts plasma membrane water permeability and their volume under osmotic shock. JOURNAL OF PLANT RESEARCH 2025; 138:161-172. [PMID: 39609337 DOI: 10.1007/s10265-024-01599-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Accepted: 11/13/2024] [Indexed: 11/30/2024]
Abstract
Protoplasts isolated from Arabidopsis leaves were used to study the initial stages of the plant cell response to osmotic stress. The role of sterols in these processes was investigated by their extraction from the protoplast plasma membrane in the presence of the oligosaccharide - methyl-β-cyclodextrin (MβCD). Depletion of membrane sterols caused by MβCD treatment did not alter protoplast volume under isosmotic conditions; however, volumes changed significantly when protoplasts were exposed to osmotic stress. Estimation of the plasma membrane water permeability coefficient (Pos), calculated from the initial rate of protoplast osmotic shrinkage, showed that control suspension is characterized by a high dispersion of the Pos values. However, Pos became more homogeneous after plasma membrane sterol depletion. Protoplasts were stained with FM 1-43 to assess how sterol extraction affects vesicular transport under osmotic shock. In order to determine the protoplast non-osmotic volume (Vb) steady-state volumes at different external osmolarities were fitted with linear dependences of the Boyle-van't Hoff (BVH) plot. It was found that sterol extraction is accompanied by a change in the slope of the BVH plot and a decrease in the apparent Vb. Several possible mechanisms behind the change in the protoplast volume and plasma membrane Pos regulation by sterols under osmotic stress are discussed.
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Affiliation(s)
- Nikita K Lapshin
- K.A. Timiryazev Institute of Plant Physiology RAS, Moscow, Russia
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Zhu J, Cao Y, Qin X, Liang Q. Budding of Asymmetric Lipid Bilayers: Effects of Cholesterol, Anionic Lipid, and Electric Field. J Phys Chem B 2024; 128:12741-12751. [PMID: 39670354 DOI: 10.1021/acs.jpcb.4c07782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2024]
Abstract
Membrane budding is vital for various cellular processes such as synaptic activity regulation, vesicle transport and release, and endocytosis/exocytosis. Although protein-mediated membrane budding has been extensively investigated, the effects of the lipid asymmetry of the two leaflets and the asymmetrically electrical environments of the cellular membrane on membrane budding remain elusive. In this work, using coarse-grained molecular dynamics simulations, we systematically investigate the impacts of lipid bilayer asymmetry and external electric fields mimicking the asymmetric membrane potential on the membrane budding. The results show that the differential stress induced by the asymmetric distribution of lipids in the two leaflets is a crucial factor for the membrane budding. The unidirectional flip of cholesterol induced by the membrane curvature and the asymmetric ion adsorption induced by the anionic lipids promote the budding process. Furthermore, the external electric field applied perpendicularly to the bilayer plane increases the transmembrane potential and produces an additional differential stress across the leaflets by imposing an asymmetric torque on the lipid headgroups in the two leaflets, facilitating the membrane budding. These findings offer insights into how the structural and the environmental asymmetry in natural cellular membranes influence membrane budding in cellular processes.
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Affiliation(s)
- Jin Zhu
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Yu Cao
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Xiaoxue Qin
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Qing Liang
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
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Iwaya C, Suzuki A, Iwata J. Loss of Sc5d results in micrognathia due to a failure in osteoblast differentiation. J Adv Res 2024; 65:153-165. [PMID: 38086515 PMCID: PMC11519736 DOI: 10.1016/j.jare.2023.12.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/30/2023] [Accepted: 12/09/2023] [Indexed: 01/01/2024] Open
Abstract
INTRODUCTION Mutations in genes related to cholesterol metabolism, or maternal diet and health status, affect craniofacial bone formation. However, the precise role of intracellular cholesterol metabolism in craniofacial bone development remains unclear. OBJECTIVE The aim of this study is to determine how cholesterol metabolism aberrations affect craniofacial bone development. METHODS Mice with a deficiency in Sc5d, which encodes an enzyme involved in cholesterol synthesis, were analyzed with histology, micro computed tomography (microCT), and cellular and molecular biological methods. RESULTS Sc5d null mice exhibited mandible hypoplasia resulting from defects in osteoblast differentiation. The activation of the hedgehog and WNT/β-catenin signaling pathways, which induce expression of osteogenic genes Col1a1 and Spp1, was compromised in the mandible of Sc5d null mice due to a failure in the formation of the primary cilium, a cell surface structure that senses extracellular cues. Treatments with an inducer of hedgehog or WNT/β-catenin signaling or with simvastatin, a drug that restores abnormal cholesterol production, partially rescued the defects in osteoblast differentiation seen in Sc5d mutant cells. CONCLUSION Our results indicate that loss of Sc5d results in mandibular hypoplasia through defective primary cilia-mediated hedgehog and WNT/β-catenin signaling pathways.
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Affiliation(s)
- Chihiro Iwaya
- Department of Diagnostic & Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX 77054, USA; Center for Craniofacial Research, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX 77054, USA
| | - Akiko Suzuki
- Department of Diagnostic & Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX 77054, USA; Center for Craniofacial Research, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX 77054, USA
| | - Junichi Iwata
- Department of Diagnostic & Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX 77054, USA; Center for Craniofacial Research, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX 77054, USA; MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA.
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Venkatraman K, Lee CT, Budin I. Setting the curve: the biophysical properties of lipids in mitochondrial form and function. J Lipid Res 2024; 65:100643. [PMID: 39303982 PMCID: PMC11513603 DOI: 10.1016/j.jlr.2024.100643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2024] [Revised: 09/13/2024] [Accepted: 09/14/2024] [Indexed: 09/22/2024] Open
Abstract
Mitochondrial membranes are defined by their diverse functions, complex geometries, and unique lipidomes. In the inner mitochondrial membrane, highly curved membrane folds known as cristae house the electron transport chain and are the primary sites of cellular energy production. The outer mitochondrial membrane is flat by contrast, but is critical for the initiation and mediation of processes key to mitochondrial physiology: mitophagy, interorganelle contacts, fission and fusion dynamics, and metabolite transport. While the lipid composition of both the inner mitochondrial membrane and outer mitochondrial membrane have been characterized across a variety of cell types, a mechanistic understanding for how individual lipid classes contribute to mitochondrial structure and function remains nebulous. In this review, we address the biophysical properties of mitochondrial lipids and their related functional roles. We highlight the intrinsic curvature of the bulk mitochondrial phospholipid pool, with an emphasis on the nuances surrounding the mitochondrially-synthesized cardiolipin. We also outline emerging questions about other lipid classes - ether lipids, and sterols - with potential roles in mitochondrial physiology. We propose that further investigation is warranted to elucidate the specific properties of these lipids and their influence on mitochondrial architecture and function.
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Affiliation(s)
- Kailash Venkatraman
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Christopher T Lee
- Department of Molecular Biology, University of California San Diego, La Jolla, CA, USA
| | - Itay Budin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA.
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Li S, Wang D, He J, Liao C, Zuo Z, Li S, Niu X. Thermophilic fungus uses anthraquinones to modulate ferrous excretion, sterol-mediated endocytosis, and iron storage in response to cold stress. Microb Biotechnol 2024; 17:e70002. [PMID: 39212141 PMCID: PMC11362841 DOI: 10.1111/1751-7915.70002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 08/07/2024] [Indexed: 09/04/2024] Open
Abstract
To date, there are no real physiological mechanisms for iron excretion in eukaryote, and no physiological "actuator" that can control all the three fundamental biologic processes of absorption, storage, and excretion. Here, we observed that the accumulation of anthraquinones by Thermomyces dupontii under cold stress can achieve this process. Through mutation analysis, we found that mutant ΔAn deficiency in anthraquinones accumulated ferrous and total free iron due to adopting a rare lifestyle with no endocytosis but accumulation of membrane-derived vesicles. Anthraquinone complement indicated that the vesicles in ΔAn could coat the extrinsic anthraquinone-induced granules to prevent contact with the fungal interiors. Detailed chemical investigation on ΔAn led to characterization of a rare oxygen-free ergosterene with unstable nature in air as the major membrane steroid in ΔAn, suggesting hypoxia inner in ΔAn cells, consistent with dramatically low oxygen-consuming rates in ΔAn. A series of physiological and metabolic analyses indicated anthraquinones were involved in exporting ferrous and promoting formation of oxygen-containing metabolites, including ergosterols for endocytosis and iron chelators for iron storage. Moreover, we found that both the anticancer agent mitoxantrone with well-known-cardiotoxicity side effect and the major terpenoid-derived polycyclic aromatics from Danshen for treating cardiovascular disease showed potent ferrous transporting capabilities in human cancer cells. Our findings provide a novel insight into the underlying mechanisms of polycyclic aromatics in nature and pharmacology, and offer a new strategy for developing potential therapeutics and agents for membrane transport, iron homestasis, and anticold.
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Affiliation(s)
- Shuhong Li
- State Key Laboratory for Conservation and Utilization of Bio‐Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life SciencesYunnan UniversityKunmingChina
| | - Donglou Wang
- State Key Laboratory for Conservation and Utilization of Bio‐Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life SciencesYunnan UniversityKunmingChina
| | - Jiangbo He
- Kunming Key Laboratory of Respiratory DiseaseKunming UniversityKunmingChina
| | - Chunhua Liao
- State Key Laboratory for Conservation and Utilization of Bio‐Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life SciencesYunnan UniversityKunmingChina
| | - Zhangxin Zuo
- State Key Laboratory for Conservation and Utilization of Bio‐Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life SciencesYunnan UniversityKunmingChina
| | - Shenghong Li
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of BotanyChinese Academy of SciencesKunmingChina
| | - Xuemei Niu
- State Key Laboratory for Conservation and Utilization of Bio‐Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life SciencesYunnan UniversityKunmingChina
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Chinnathambi S, Adithyan A, Chandrashekar M. Lipid role in synapse and nuclear envelope-associated endocytic pathways in Tauopathy. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 143:387-409. [PMID: 39843142 DOI: 10.1016/bs.apcsb.2024.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2025]
Abstract
Lipids play an essential role in synaptic function, significantly impacting synaptic physiology through their dynamic nature and signaling capabilities. Membrane lipids, including cholesterol, phospholipids, and gangliosides, are crucial for synaptic organization and function. They act as structural integrators and signaling molecules, guiding vesicle intracellular movement and regulating enzyme activity to support neuronal activity. The lipid compositions of pre-synaptic and post-synaptic membranes influence vesicle generation and receptor mobility, highlighting their active involvement in synaptic processes. Astrocytes also contribute to synaptic health by upholding the blood-brain barrier, regulating ion levels, and providing metabolic support. Lipid-mediated processes control synaptic plasticity and development, with astrocytes playing a crucial role in glutamate homeostasis. Amyloid-beta and Tau proteins are key in Alzheimer's disease (AD), where synaptic disruption leads to cognitive deficits. Clathrin-mediated endocytosis (CME) and caveolin-mediated endocytosis are critical pathways for lipid-mediated synaptic function, with disruptions in these pathways contributing to AD pathogenesis.
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Affiliation(s)
- Subashchandrabose Chinnathambi
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences Hospital (NIMHANS), Institute of National Importance, Bangalore, Karnataka, India
| | - Anusree Adithyan
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences Hospital (NIMHANS), Institute of National Importance, Bangalore, Karnataka, India
| | - Madhura Chandrashekar
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences Hospital (NIMHANS), Institute of National Importance, Bangalore, Karnataka, India
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10
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Ocket E, Matthaeus C. Insights in caveolae protein structure arrangements and their local lipid environment. Biol Chem 2024; 0:hsz-2024-0046. [PMID: 38970809 DOI: 10.1515/hsz-2024-0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/19/2024] [Indexed: 07/08/2024]
Abstract
Caveolae are 50-80 nm sized plasma membrane invaginations found in adipocytes, endothelial cells or fibroblasts. They are involved in endocytosis, lipid uptake and the regulation of the cellular lipid metabolism as well as sensing and adapting to changes in plasma membrane tension. Caveolae are characterized by their unique lipid composition and their specific protein coat consisting of caveolin and cavin proteins. Recently, detailed structural information was obtained for the major caveolae protein caveolin1 showing the formation of a disc-like 11-mer protein complex. Furthermore, the importance of the cavin disordered regions in the generation of cavin trimers and caveolae at the plasma membrane were revealed. Thus, finally, structural insights about the assembly of the caveolar coat can be elucidated. Here, we review recent developments in caveolae structural biology with regard to caveolae coat formation and caveolae curvature generation. Secondly, we discuss the importance of specific lipid species necessary for caveolae curvature and formation. In the last years, it was shown that specifically sphingolipids, cholesterol and fatty acids can accumulate in caveolae invaginations and may drive caveolae endocytosis. Throughout, we summarize recent studies in the field and highlight future research directions.
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Affiliation(s)
- Esther Ocket
- Institute of Nutritional Science, Cellular Physiology of Nutrition, University of Potsdam, Karl-Liebknecht-Str. 24/25, Building 29, Room 0.08, D-14476 Potsdam, Germany
| | - Claudia Matthaeus
- Institute of Nutritional Science, Cellular Physiology of Nutrition, University of Potsdam, Karl-Liebknecht-Str. 24/25, Building 29, Room 0.08, D-14476 Potsdam, Germany
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Miyazaki S, Shimizu N, Miyahara H, Teranishi H, Umeda R, Yano S, Shimada T, Shiraishi H, Komiya K, Katoh A, Yoshimura A, Hanada R, Hanada T. DHCR7 links cholesterol synthesis with neuronal development and axonal integrity. Biochem Biophys Res Commun 2024; 712-713:149932. [PMID: 38626530 DOI: 10.1016/j.bbrc.2024.149932] [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: 03/19/2024] [Revised: 04/03/2024] [Accepted: 04/10/2024] [Indexed: 04/18/2024]
Abstract
The DHCR7 enzyme converts 7-DHC into cholesterol. Mutations in DHCR7 can block cholesterol production, leading to abnormal accumulation of 7-DHC and causing Smith-Lemli-Opitz syndrome (SLOS). SLOS is an autosomal recessive disorder characterized by multiple malformations, including microcephaly, intellectual disability, behavior reminiscent of autism, sleep disturbances, and attention-deficit/hyperactivity disorder (ADHD)-like hyperactivity. Although 7-DHC affects neuronal differentiation in ex vivo experiments, the precise mechanism of SLOS remains unclear. We generated Dhcr7 deficient (dhcr7-/-) zebrafish that exhibited key features of SLOS, including microcephaly, decreased neural stem cell pools, and behavioral phenotypes similar to those of ADHD-like hyperactivity. These zebrafish demonstrated compromised myelination, synaptic anomalies, and neurotransmitter imbalances. The axons of the dhcr7-/- zebrafish showed increased lysosomes and attenuated autophagy, suggesting that autophagy-related neuronal homeostasis is disrupted.
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Affiliation(s)
- Shuya Miyazaki
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan; Department of Respiratory Medicine and Infectious Diseases, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Nobuyuki Shimizu
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Hiroaki Miyahara
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Aichi, Japan
| | - Hitoshi Teranishi
- Department of Neurophysiology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Ryohei Umeda
- Department of Advanced Medical Sciences, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Shinji Yano
- Institute for Research Management, Oita University, Yufu, Oita, Japan
| | - Tatsuo Shimada
- Oita Medical Technology School, Japan College of Judo-Therapy, Acupuncture & Moxibustion Therapy, Oita, Japan
| | - Hiroshi Shiraishi
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Kosaku Komiya
- Department of Respiratory Medicine and Infectious Diseases, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Akira Katoh
- Department of Clinical Pharmacology & Therapeutics, Oita University, Yufu, Oita, Japan
| | - Akihiko Yoshimura
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Reiko Hanada
- Department of Neurophysiology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Toshikatsu Hanada
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan.
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12
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Nawara TJ, Yuan J, Seeley LD, Sztul E, Mattheyses AL. Fluidic shear stress alters clathrin dynamics and vesicle formation in endothelial cells. Biophys J 2024:S0006-3495(24)00390-4. [PMID: 38853434 DOI: 10.1016/j.bpj.2024.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/26/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024] Open
Abstract
Endothelial cells (ECs) experience a variety of highly dynamic mechanical stresses. Among others, cyclic stretch and increased plasma membrane tension inhibit clathrin-mediated endocytosis (CME) in non-ECs. It remains elusive how ECs maintain CME in these biophysically unfavorable conditions. Previously, we have used simultaneous two-wavelength axial ratiometry (STAR) microscopy to show that endocytic dynamics are similar between statically cultured human umbilical vein endothelial cells (HUVECs) and fibroblast-like Cos-7 cells. Here, we asked whether biophysical stresses generated by blood flow influence CME. We used our data processing platform-DrSTAR-to examine if clathrin dynamics are altered in HUVECs after experiencing fluidic shear stress (FSS). We found that HUVECs cultivated under a physiological level of FSS had increased clathrin dynamics compared with static controls. FSS increased both clathrin-coated vesicle formation and nonproductive flat clathrin lattices by 2.3-fold and 1.9-fold, respectively. The curvature-positive events had significantly delayed curvature initiation relative to clathrin recruitment in flow-stimulated cells, highlighting a shift toward flat-to-curved clathrin transitions in vesicle formation. Overall, our findings indicate that clathrin dynamics and clathrin-coated vesicle formation can be modulated by the local physiological environment and represent an important regulatory mechanism.
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Affiliation(s)
- Tomasz J Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jie Yuan
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Leslie D Seeley
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Elizabeth Sztul
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama.
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13
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Sengupta S, Yaeger JD, Schultz MM, Francis KR. Dishevelled localization and function are differentially regulated by structurally distinct sterols. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.14.593701. [PMID: 38798572 PMCID: PMC11118412 DOI: 10.1101/2024.05.14.593701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The Dishevelled (DVL) family of proteins form supramolecular protein and lipid complexes at the cytoplasmic interface of the plasma membrane to regulate tissue patterning, proliferation, cell polarity, and oncogenic processes through DVL-dependent signaling, such as Wnt/β-catenin. While DVL binding to cholesterol is required for its membrane association, the specific structural requirements and cellular impacts of DVL-sterol association are unclear. We report that intracellular sterols which accumulate within normal and pathological conditions cause aberrant DVL activity. In silico and molecular analyses suggested orientation of the β- and α-sterol face within the DVL-PDZ domain regulates DVL-sterol binding. Intracellular accumulation of naturally occurring sterols impaired DVL2 plasma membrane association, inducing DVL2 nuclear localization via Foxk2. Changes to intracellular sterols also selectively impaired DVL2 protein-protein interactions This work identifies sterol specificity as a regulator of DVL signaling, suggests intracellular sterols cause distinct impacts on DVL activity, and supports a role for intracellular sterol homeostasis in cell signaling.
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Affiliation(s)
- Sonali Sengupta
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Jazmine D.W. Yaeger
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Maycie M. Schultz
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Kevin R. Francis
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD, 57104, USA
- Department of Pediatrics, University of South Dakota Sanford School of Medicine, Sioux Falls, SD, 57105, USA
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14
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Okayama A, Hoshino T, Wada K, Takahashi H. Comparison of structural effects of cholesterol, lanosterol, and oxysterol on phospholipid (POPC) bilayers. Chem Phys Lipids 2024; 259:105376. [PMID: 38325710 DOI: 10.1016/j.chemphyslip.2024.105376] [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: 10/12/2023] [Revised: 12/26/2023] [Accepted: 01/31/2024] [Indexed: 02/09/2024]
Abstract
Membrane sterols contribute to the function of biomembranes by regulating the physical properties of the lipid bilayers. Cholesterol, a typical mammalian sterol, is biosynthesized by oxidation of lanosterol. From a molecular evolutionary perspective, lanosterol is considered the ancestral molecule of cholesterol. Here, we studied whether cholesterol is superior to lanosterol in regulating the physical properties of the lipid bilayer in terms of the structural effect on model biomembranes composed of a phospholipid. For comparison, oxysterol, which is formed by oxidation of cholesterol, was also studied. The phospholipid used was 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), which is abundantly found in mammalian biomembranes, and 7β-hydroxycholesterol, which is highly cytotoxic, was used as the oxysterol. The apparent molecular volume was calculated from the mass density determined by the flotation method using H2O and D2O, and the bilayer thickness was determined by reconstructing the electron density distribution from X-ray diffraction data of the POPC/sterol mixtures at a sterol concentration of 30 mol%. The apparent occupied area at the bilayer surface was calculated from the above two structural data. The cholesterol system had the thickest bilayer thickness and the smallest occupied area of the three sterols studied here. This indicates that the POPC/cholesterol bilayer has a better barrier property than the other two systems. Compared to cholesterol, the effects of lanosterol and 7β-hydroxycholesterol on lipid bilayer properties can be interpreted as suboptimal for the function of mammalian biomembranes.
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Affiliation(s)
- Ayumi Okayama
- Division of Pure and Applied Science, Faculty of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
| | - Tatsuya Hoshino
- Division of Pure and Applied Science, Faculty of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
| | - Kohei Wada
- Division of Pure and Applied Science, Faculty of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan
| | - Hiroshi Takahashi
- Division of Pure and Applied Science, Faculty of Science and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan.
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15
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Mandal T, Biswas A, Ghosh T, Manikandan S, Kundu A, Banerjee A, Mitra D, Sinha B. Mechano-regulation by clathrin pit-formation and passive cholesterol-dependent tubules during de-adhesion. Cell Mol Life Sci 2024; 81:43. [PMID: 38217571 PMCID: PMC10787898 DOI: 10.1007/s00018-023-05072-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 11/10/2023] [Accepted: 11/30/2023] [Indexed: 01/15/2024]
Abstract
Adherent cells ensure membrane homeostasis during de-adhesion by various mechanisms, including endocytosis. Although mechano-chemical feedbacks involved in this process have been studied, the step-by-step build-up and resolution of the mechanical changes by endocytosis are poorly understood. To investigate this, we studied the de-adhesion of HeLa cells using a combination of interference reflection microscopy, optical trapping and fluorescence experiments. We found that de-adhesion enhanced membrane height fluctuations of the basal membrane in the presence of an intact cortex. A reduction in the tether force was also noted at the apical side. However, membrane fluctuations reveal phases of an initial drop in effective tension followed by saturation. The area fractions of early (Rab5-labelled) and recycling (Rab4-labelled) endosomes, as well as transferrin-labelled pits close to the basal plasma membrane, also transiently increased. On blocking dynamin-dependent scission of endocytic pits, the regulation of fluctuations was not blocked, but knocking down AP2-dependent pit formation stopped the tension recovery. Interestingly, the regulation could not be suppressed by ATP or cholesterol depletion individually but was arrested by depleting both. The data strongly supports Clathrin and AP2-dependent pit-formation to be central to the reduction in fluctuations confirmed by super-resolution microscopy. Furthermore, we propose that cholesterol-dependent pits spontaneously regulate tension under ATP-depleted conditions.
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Affiliation(s)
- Tithi Mandal
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246, India
| | - Arikta Biswas
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246, India
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Tanmoy Ghosh
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246, India
| | - Sreekanth Manikandan
- NORDITA, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, 10691, Stockholm, Sweden
| | - Avijit Kundu
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246, India
- Experimental Physics I, Universität Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Ayan Banerjee
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246, India
| | - Dhrubaditya Mitra
- NORDITA, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, 10691, Stockholm, Sweden
| | - Bidisha Sinha
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, Mohanpur, 741246, India.
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16
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Pöhnl M, Trollmann MFW, Böckmann RA. Nonuniversal impact of cholesterol on membranes mobility, curvature sensing and elasticity. Nat Commun 2023; 14:8038. [PMID: 38081812 PMCID: PMC10713574 DOI: 10.1038/s41467-023-43892-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Biological membranes, composed mainly of phospholipids and cholesterol, play a vital role as cellular barriers. They undergo localized reshaping in response to environmental cues and protein interactions, with the energetics of deformations crucial for exerting biological functions. This study investigates the non-universal role of cholesterol on the structure and elasticity of saturated and unsaturated lipid membranes. Our study uncovers a highly cooperative relationship between thermal membrane bending and local cholesterol redistribution, with cholesterol showing a strong preference for the compressed membrane leaflet. Remarkably, in unsaturated membranes, increased cholesterol mobility enhances cooperativity, resulting in membrane softening despite membrane thickening and lipid compression caused by cholesterol. These findings elucidate the intricate interplay between thermodynamic forces and local molecular interactions that govern collective properties of membranes.
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Affiliation(s)
- Matthias Pöhnl
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Marius F W Trollmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Erlangen National High Perfomance Computing Center (NHR@FAU), Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
- Erlangen National High Perfomance Computing Center (NHR@FAU), Erlangen, Germany.
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17
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Navyasree KV, Ramesh ST, Umasankar PK. Cholesterol regulates insulin-induced mTORC1 signaling. J Cell Sci 2023; 136:jcs261402. [PMID: 37921368 DOI: 10.1242/jcs.261402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023] Open
Abstract
The rapid activation of the crucial kinase mechanistic target of rapamycin complex-1 (mTORC1) by insulin is key to cell growth in mammals, but the regulatory factors remain unclear. Here, we demonstrate that cholesterol plays a crucial role in the regulation of insulin-stimulated mTORC1 signaling. The rapid progression of insulin-induced mTORC1 signaling declines in sterol-depleted cells and restores in cholesterol-repleted cells. In insulin-stimulated cells, cholesterol promotes recruitment of mTORC1 onto lysosomes without affecting insulin-induced dissociation of the TSC complex from lysosomes, thereby enabling complete activation of mTORC1. We also show that under prolonged starvation conditions, cholesterol coordinates with autophagy to support mTORC1 reactivation on lysosomes thereby restoring insulin-responsive mTORC1 signaling. Furthermore, we identify that fibroblasts from individuals with Smith-Lemli-Opitz Syndrome (SLOS) and model HeLa-SLOS cells, which are deficient in cholesterol biosynthesis, exhibit defects in the insulin-mTORC1 growth axis. These defects are rescued by supplementation of exogenous cholesterol or by expression of constitutively active Rag GTPase, a downstream activator of mTORC1. Overall, our findings propose novel signal integration mechanisms to achieve spatial and temporal control of mTORC1-dependent growth signaling and their aberrations in disease.
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Affiliation(s)
- Kolaparamba V Navyasree
- Intracellular Trafficking Laboratory, Transdisciplinary Biology Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala 695014, India
- PhD Program, Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Shikha T Ramesh
- Intracellular Trafficking Laboratory, Transdisciplinary Biology Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala 695014, India
- PhD Program, Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Perunthottathu K Umasankar
- Intracellular Trafficking Laboratory, Transdisciplinary Biology Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala 695014, India
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18
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Sun Q, Liu D, Cui W, Cheng H, Huang L, Zhang R, Gu J, Liu S, Zhuang X, Lu Y, Chu B, Li J. Cholesterol mediated ferroptosis suppression reveals essential roles of Coenzyme Q and squalene. Commun Biol 2023; 6:1108. [PMID: 37914914 PMCID: PMC10620397 DOI: 10.1038/s42003-023-05477-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 10/17/2023] [Indexed: 11/03/2023] Open
Abstract
Recent findings have shown that fatty acid metabolism is profoundly involved in ferroptosis. However, the role of cholesterol in this process remains incompletely understood. In this work, we show that modulating cholesterol levels changes vulnerability of cells to ferroptosis. Cholesterol alters metabolic flux of the mevalonate pathway by promoting Squalene Epoxidase (SQLE) degradation, a rate limiting step in cholesterol biosynthesis, thereby increasing both CoQ10 and squalene levels. Importantly, whereas inactivation of Farnesyl-Diphosphate Farnesyltransferase 1 (FDFT1), the branch point of cholesterol biosynthesis pathway, exhibits minimal effect on ferroptosis, simultaneous inhibition of both CoQ10 and squalene biosynthesis completely abrogates the effect of cholesterol. Mouse models of ischemia-reperfusion and doxorubicin induced hepatoxicity confirm the protective role of cholesterol in ferroptosis. Our study elucidates a potential role of ferroptosis in diseases related to dysregulation of cholesterol metabolism and suggests a possible therapeutic target that involves ferroptotic cell death.
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Affiliation(s)
- Qi Sun
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Diming Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Weiwei Cui
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Huimin Cheng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Lixia Huang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Ruihao Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Junlian Gu
- School of Nursing and Rehabilitation, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Shuo Liu
- Department of Geriatric Medicine, Qilu Hospital, Shandong University, Wenhuaxi Road 107, Jinan, Shandong, 250012, China
| | - Xiao Zhuang
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China
| | - Yi Lu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.
| | - Bo Chu
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.
| | - Jian Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China.
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19
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Pistek M, Kahlig CI, Hackl M, Unterthurner S, Kraus B, Grabherr R, Grillari J, Hernandez Bort JA. Comprehensive mRNA-sequencing-based characterization of three HEK-293 cell lines during an rAAV production process for gene therapy applications. Biotechnol J 2023; 18:e2200513. [PMID: 37191240 DOI: 10.1002/biot.202200513] [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: 10/11/2022] [Revised: 04/20/2023] [Accepted: 05/10/2023] [Indexed: 05/17/2023]
Abstract
Human embryonal kidney cells (HEK-293) are the most common host cells used for transient recombinant adeno-associated virus (rAAV) production in pharmaceutical industry. To better cover the expected gene therapy product demands in the future, different traditional strategies such as cell line sub-cloning and/or addition of chemical substances to the fermentation media have been used to maximize titers and improve product quality. A more effective and advanced approach to boost yield can be envisaged by characterizing the transcriptome of different HEK-293 cell line pedigrees with distinct rAAV productivity patterns to subsequently identify potential gene targets for cell engineering. In this work, the mRNA expression profile of three HEK-293 cell lines, resulting in various yields during a fermentation batch process for rAAV production, was investigated to gain basic insight into cell variability and eventually to identify genes that correlate with productivity. Mock runs using only transfection reagents were performed in parallel as a control. It finds significant differences in gene regulatory behaviors between the three cell lines at different growth and production stages. The evaluation of these transcriptomics profiles combined with collected in-process control parameters and titers shed some light on potential cell engineering targets to maximize transient production of rAAV in HEK-293 cells.
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Affiliation(s)
- Martina Pistek
- Biotherapeutics Process Development, Baxalta Innovations GmbH, a part of Takeda companies, Orth an der Donau, Austria
| | - Carolin-Isabel Kahlig
- Biotherapeutics Process Development, Baxalta Innovations GmbH, a part of Takeda companies, Orth an der Donau, Austria
| | | | - Sabine Unterthurner
- Biotherapeutics Process Development, Baxalta Innovations GmbH, a part of Takeda companies, Orth an der Donau, Austria
| | - Barbara Kraus
- Biotherapeutics Process Development, Baxalta Innovations GmbH, a part of Takeda companies, Orth an der Donau, Austria
| | - Reingard Grabherr
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Johannes Grillari
- TAmiRNA, Vienna, Austria
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Collaboration with AUVA, Vienna, Austria
| | - Juan A Hernandez Bort
- Biotherapeutics Process Development, Baxalta Innovations GmbH, a part of Takeda companies, Orth an der Donau, Austria
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20
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Brocks JJ, Nettersheim BJ, Adam P, Schaeffer P, Jarrett AJM, Güneli N, Liyanage T, van Maldegem LM, Hallmann C, Hope JM. Lost world of complex life and the late rise of the eukaryotic crown. Nature 2023:10.1038/s41586-023-06170-w. [PMID: 37286610 DOI: 10.1038/s41586-023-06170-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 05/04/2023] [Indexed: 06/09/2023]
Abstract
Eukaryotic life appears to have flourished surprisingly late in the history of our planet. This view is based on the low diversity of diagnostic eukaryotic fossils in marine sediments of mid-Proterozoic age (around 1,600 to 800 million years ago) and an absence of steranes, the molecular fossils of eukaryotic membrane sterols1,2. This scarcity of eukaryotic remains is difficult to reconcile with molecular clocks that suggest that the last eukaryotic common ancestor (LECA) had already emerged between around 1,200 and more than 1,800 million years ago. LECA, in turn, must have been preceded by stem-group eukaryotic forms by several hundred million years3. Here we report the discovery of abundant protosteroids in sedimentary rocks of mid-Proterozoic age. These primordial compounds had previously remained unnoticed because their structures represent early intermediates of the modern sterol biosynthetic pathway, as predicted by Konrad Bloch4. The protosteroids reveal an ecologically prominent 'protosterol biota' that was widespread and abundant in aquatic environments from at least 1,640 to around 800 million years ago and that probably comprised ancient protosterol-producing bacteria and deep-branching stem-group eukaryotes. Modern eukaryotes started to appear in the Tonian period (1,000 to 720 million years ago), fuelled by the proliferation of red algae (rhodophytes) by around 800 million years ago. This 'Tonian transformation' emerges as one of the most profound ecological turning points in the Earth's history.
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Affiliation(s)
- Jochen J Brocks
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia.
| | - Benjamin J Nettersheim
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia.
- MARUM-Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany.
| | - Pierre Adam
- Université de Strasbourg, CNRS, Institut de Chimie de Strasbourg UMR 7177, Strasbourg, France
| | - Philippe Schaeffer
- Université de Strasbourg, CNRS, Institut de Chimie de Strasbourg UMR 7177, Strasbourg, France
| | - Amber J M Jarrett
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Northern Territory Geological Survey, Darwin, Northern Territory, Australia
| | - Nur Güneli
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Tharika Liyanage
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Lennart M van Maldegem
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | | | - Janet M Hope
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
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21
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Abstract
The formation of membrane vesicles is a common feature in all eukaryotes. Lipid rafts are the best-studied example of membrane domains for both eukaryotes and prokaryotes, and their existence also is suggested in Archaea membranes. Lipid rafts are involved in the formation of transport vesicles, endocytic vesicles, exocytic vesicles, synaptic vesicles and extracellular vesicles, as well as enveloped viruses. Two mechanisms of how rafts are involved in vesicle formation have been proposed: first, that raft proteins and/or lipids located in lipid rafts associate with coat proteins that form a budding vesicle, and second, vesicle budding is triggered by enzymatic generation of cone-shaped ceramides and inverted cone-shaped lyso-phospholipids. In both cases, induction of curvature is also facilitated by the relaxation of tension in the raft domain. In this Review, we discuss the role of raft-derived vesicles in several intracellular trafficking pathways. We also highlight their role in different pathways of endocytosis, and in the formation of intraluminal vesicles (ILVs) through budding inwards from the multivesicular body (MVB) membrane, because rafts inside MVB membranes are likely to be involved in loading RNA into ILVs. Finally, we discuss the association of glycoproteins with rafts via the glycocalyx.
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Affiliation(s)
- Karolina Sapoń
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Rafał Mańka
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Teresa Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Tadeusz Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
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22
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Chattopadhyay A, Sharma A. Smith-Lemli-Opitz syndrome: A pathophysiological manifestation of the Bloch hypothesis. Front Mol Biosci 2023; 10:1120373. [PMID: 36714259 PMCID: PMC9878332 DOI: 10.3389/fmolb.2023.1120373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/02/2023] [Indexed: 01/15/2023] Open
Abstract
The biosynthesis of cholesterol, an essential component of higher eukaryotic membranes, was worked out by Konrad Bloch (and Feodor Lynen) in the 1960s and they received the Nobel Prize around that time in recognition of their pioneering contributions. An elegant consequence of this was a hypothesis proposed by Konrad Bloch (the Bloch hypothesis) which suggests that each subsequent intermediate in the cholesterol biosynthesis pathway is superior in supporting membrane function in higher eukaryotes relative to its precursor. In this review, we discuss an autosomal recessive metabolic disorder, known as Smith-Lemli-Opitz syndrome (SLOS), associated with a defect in the Kandutsch-Russell pathway of cholesterol biosynthesis that results in accumulation of the immediate precursor of cholesterol in its biosynthetic pathway (7-dehydrocholesterol) and an altered cholesterol to total sterol ratio. Patients suffering from SLOS have several developmental, behavioral and cognitive abnormalities for which no drug is available yet. We characterize SLOS as a manifestation of the Bloch hypothesis and review its molecular etiology and current treatment. We further discuss defective Hedgehog signaling in SLOS and focus on the role of the serotonin1A receptor, a representative neurotransmitter receptor belonging to the GPCR family, in SLOS. Notably, ligand binding activity and cellular signaling of serotonin1A receptors are impaired in SLOS-like condition. Importantly, cellular localization and intracellular trafficking of the serotonin1A receptor (which constitute an important determinant of a GPCR cellular function) are compromised in SLOS. We highlight some of the recent developments and emerging concepts in SLOS pathobiology and suggest that novel therapies based on trafficking defects of target receptors could provide new insight into treatment of SLOS.
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Affiliation(s)
- Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India,Academy of Scientific and Innovative Research, Ghaziabad, India,*Correspondence: Amitabha Chattopadhyay,
| | - Ashwani Sharma
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India,Academy of Scientific and Innovative Research, Ghaziabad, India
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23
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Madsen JJ, Rossman JS. Cholesterol and M2 Rendezvous in Budding and Scission of Influenza A Virus. Subcell Biochem 2023; 106:441-459. [PMID: 38159237 DOI: 10.1007/978-3-031-40086-5_16] [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] [Indexed: 01/03/2024]
Abstract
The cholesterol of the host cell plasma membrane and viral M2 protein plays a crucial role in multiple stages of infection and replication of the influenza A virus. Cholesterol is required for the formation of heterogeneous membrane microdomains (or rafts) in the budozone of the host cell that serves as assembly sites for the viral components. The raft microstructures act as scaffolds for several proteins. Cholesterol may further contribute to the mechanical forces necessary for membrane scission in the last stage of budding and help to maintain the stability of the virus envelope. The M2 protein has been shown to cause membrane scission in model systems by promoting the formation of curved lipid bilayer structures that, in turn, can lead to membrane vesicles budding off or scission intermediates. Membrane remodeling by M2 is intimately linked with cholesterol as it affects local lipid composition, fluidity, and stability of the membrane. Thus, both cholesterol and M2 protein contribute to the efficient and proper release of newly formed influenza viruses from the virus-infected cells.
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Affiliation(s)
- Jesper J Madsen
- Global and Planetary Health, Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA.
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Jeremy S Rossman
- School of Biosciences, University of Kent, Canterbury, Kent, UK
- Research-Aid Networks, Chicago, IL, USA
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24
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Freel BA, Kelvington BA, Sengupta S, Mukherjee M, Francis KR. Sterol dysregulation in Smith-Lemli-Opitz syndrome causes astrocyte immune reactivity through microglia crosstalk. Dis Model Mech 2022; 15:dmm049843. [PMID: 36524414 PMCID: PMC10655813 DOI: 10.1242/dmm.049843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/17/2022] [Indexed: 12/23/2022] Open
Abstract
Owing to the need for de novo cholesterol synthesis and cholesterol-enriched structures within the nervous system, cholesterol homeostasis is critical to neurodevelopment. Diseases caused by genetic disruption of cholesterol biosynthesis, such as Smith-Lemli-Opitz syndrome, which is caused by mutations in 7-dehydrocholesterol reductase (DHCR7), frequently result in broad neurological deficits. Although astrocytes regulate multiple neural processes ranging from cell migration to network-level communication, immunological activation of astrocytes is a hallmark pathology in many diseases. However, the impact of DHCR7 on astrocyte function and immune activation remains unknown. We demonstrate that astrocytes from Dhcr7 mutant mice display hallmark signs of reactivity, including increased expression of glial fibrillary acidic protein (GFAP) and cellular hypertrophy. Transcript analyses demonstrate extensive Dhcr7 astrocyte immune activation, hyper-responsiveness to glutamate stimulation and altered calcium flux. We further determine that the impacts of Dhcr7 are not astrocyte intrinsic but result from non-cell-autonomous effects of microglia. Our data suggest that astrocyte-microglia crosstalk likely contributes to the neurological phenotypes observed in disorders of cholesterol biosynthesis. Additionally, these data further elucidate a role for cholesterol metabolism within the astrocyte-microglia immune axis, with possible implications in other neurological diseases.
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Affiliation(s)
- Bethany A. Freel
- Basic Biomedical Sciences, University of South Dakota, Vermillion, SD 57069, USA
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Benjamin A. Kelvington
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Sonali Sengupta
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Malini Mukherjee
- Functional Genomics and Bioinformatics Core, Sanford Research, Sioux Falls, SD 57104, USA
| | - Kevin R. Francis
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, SD 57104, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA
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25
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Matthaeus C, Sochacki KA, Dickey AM, Puchkov D, Haucke V, Lehmann M, Taraska JW. The molecular organization of differentially curved caveolae indicates bendable structural units at the plasma membrane. Nat Commun 2022; 13:7234. [PMID: 36433988 PMCID: PMC9700719 DOI: 10.1038/s41467-022-34958-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022] Open
Abstract
Caveolae are small coated plasma membrane invaginations with diverse functions. Caveolae undergo curvature changes. Yet, it is unclear which proteins regulate this process. To address this gap, we develop a correlative stimulated emission depletion (STED) fluorescence and platinum replica electron microscopy imaging (CLEM) method to image proteins at single caveolae. Caveolins and cavins are found at all caveolae, independent of curvature. EHD2 is detected at both low and highly curved caveolae. Pacsin2 associates with low curved caveolae and EHBP1 with mostly highly curved caveolae. Dynamin is absent from caveolae. Cells lacking dynamin show no substantial changes to caveolae, suggesting that dynamin is not directly involved in caveolae curvature. We propose a model where caveolins, cavins, and EHD2 assemble as a cohesive structural unit regulated by intermittent associations with pacsin2 and EHBP1. These coats can flatten and curve to enable lipid traffic, signaling, and changes to the surface area of the cell.
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Affiliation(s)
- Claudia Matthaeus
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kem A Sochacki
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Andrea M Dickey
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- Faculty of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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26
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Abstract
Monitoring the proteins and lipids that mediate all cellular processes requires imaging methods with increased spatial and temporal resolution. STED (stimulated emission depletion) nanoscopy enables fast imaging of nanoscale structures in living cells but is limited by photobleaching. Here, we present event-triggered STED, an automated multiscale method capable of rapidly initiating two-dimensional (2D) and 3D STED imaging after detecting cellular events such as protein recruitment, vesicle trafficking and second messengers activity using biosensors. STED is applied in the vicinity of detected events to maximize the temporal resolution. We imaged synaptic vesicle dynamics at up to 24 Hz, 40 ms after local calcium activity; endocytosis and exocytosis events at up to 11 Hz, 40 ms after local protein recruitment or pH changes; and the interaction between endosomal vesicles at up to 3 Hz, 70 ms after approaching one another. Event-triggered STED extends the capabilities of live nanoscale imaging, enabling novel biological observations in real time.
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Affiliation(s)
- Jonatan Alvelid
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Martina Damenti
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Chiara Sgattoni
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ilaria Testa
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden.
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27
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Ariano C, Riganti C, Corà D, Valdembri D, Mana G, Astanina E, Serini G, Bussolino F, Doronzo G. TFEB controls integrin-mediated endothelial cell adhesion by the regulation of cholesterol metabolism. Angiogenesis 2022; 25:471-492. [PMID: 35545719 PMCID: PMC9519734 DOI: 10.1007/s10456-022-09840-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/18/2022] [Indexed: 11/30/2022]
Abstract
The dynamic integrin-mediated adhesion of endothelial cells (ECs) to the surrounding ECM is fundamental for angiogenesis both in physiological and pathological conditions, such as embryonic development and cancer progression. The dynamics of EC-to-ECM adhesions relies on the regulation of the conformational activation and trafficking of integrins. Here, we reveal that oncogenic transcription factor EB (TFEB), a known regulator of lysosomal biogenesis and metabolism, also controls a transcriptional program that influences the turnover of ECM adhesions in ECs by regulating cholesterol metabolism. We show that TFEB favors ECM adhesion turnover by promoting the transcription of genes that drive the synthesis of cholesterol, which promotes the aggregation of caveolin-1, and the caveolin-dependent endocytosis of integrin β1. These findings suggest that TFEB might represent a novel target for the pharmacological control of pathological angiogenesis and bring new insights in the mechanism sustaining TFEB control of endocytosis.
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Affiliation(s)
- Camilla Ariano
- Department of Oncology, University of Torino, Candiolo, Italy.,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy
| | - Chiara Riganti
- Department of Oncology, University of Torino, Torino, Italy
| | - Davide Corà
- Department of Translational Medicine, Piemonte Orientale University, Novara, Italy.,Center for Translational Research on Autoimmune and Allergic Diseases-CAAD, Novara, Italy
| | - Donatella Valdembri
- Department of Oncology, University of Torino, Candiolo, Italy.,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy
| | - Giulia Mana
- Department of Oncology, University of Torino, Candiolo, Italy.,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy
| | - Elena Astanina
- Department of Oncology, University of Torino, Candiolo, Italy.,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy
| | - Guido Serini
- Department of Oncology, University of Torino, Candiolo, Italy.,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy
| | - Federico Bussolino
- Department of Oncology, University of Torino, Candiolo, Italy. .,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy.
| | - Gabriella Doronzo
- Department of Oncology, University of Torino, Candiolo, Italy. .,Candiolo Cancer Institute- FPO-IRCCS, Candiolo, Italy.
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28
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Dutta A, Sarkar P, Shrivastava S, Chattopadhyay A. Effect of Hypoxia on the Function of the Human Serotonin 1A Receptor. ACS Chem Neurosci 2022; 13:1456-1466. [PMID: 35467841 DOI: 10.1021/acschemneuro.2c00181] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Cellular hypoxia causes numerous pathophysiological conditions associated with the disruption of oxygen homeostasis. Under oxygen-deficient conditions, cells adapt by controlling the cellular functions to facilitate the judicious use of available oxygen, such as cessation of cell growth and proliferation. In higher eukaryotes, the process of cholesterol biosynthesis is intimately coupled to the availability of oxygen, where the synthesis of one molecule of cholesterol requires 11 molecules of O2. Cholesterol is an essential component of higher eukaryotic membranes and is crucial for the physiological functions of several membrane proteins and receptors. The serotonin1A receptor, an important neurotransmitter G protein-coupled receptor associated with cognition and memory, has previously been shown to depend on cholesterol for its signaling and function. In this work, in order to explore the interdependence of oxygen levels, cholesterol biosynthesis, and the function of the serotonin1A receptor, we developed a cellular hypoxia model to explore the function of the human serotonin1A receptor heterologously expressed in Chinese hamster ovary cells. We observed cell cycle arrest at G1/S phase and the accumulation of lanosterol in cell membranes under hypoxic conditions, thereby validating our cellular model. Interestingly, we observed a significant reduction in ligand binding and disruption of downstream cAMP signaling of the serotonin1A receptor under hypoxic conditions. To the best of our knowledge, our results represent the first report linking the function of the serotonin1A receptor with hypoxia. From a broader perspective, these results contribute to our overall understanding of the molecular basis underlying neurological conditions often associated with hypoxia-induced brain dysfunction.
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Affiliation(s)
- Aritri Dutta
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Sandeep Shrivastava
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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29
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Glitscher M, Hildt E. Endosomal Cholesterol in Viral Infections - A Common Denominator? Front Physiol 2021; 12:750544. [PMID: 34858206 PMCID: PMC8632007 DOI: 10.3389/fphys.2021.750544] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 10/22/2021] [Indexed: 12/24/2022] Open
Abstract
Cholesterol has gained tremendous attention as an essential lipid in the life cycle of virtually all viruses. These seem to have developed manifold strategies to modulate the cholesterol metabolism to the side of lipid uptake and de novo synthesis. In turn, affecting the cholesterol homeostasis has emerged as novel broad-spectrum antiviral strategy. On the other hand, the innate immune system is similarly regulated by the lipid and stimulated by its derivatives. This certainly requires attention in the design of antiviral strategies aiming to decrease cellular cholesterol, as evidence accumulates that withdrawal of cholesterol hampers innate immunity. Secondly, there are exceptions to the rule of the abovementioned virus-induced metabolic shift toward cholesterol anabolism. It therefore is of interest to dissect underlying regulatory mechanisms, which we aimed for in this minireview. We further collected evidence for intracellular cholesterol concentrations being less important in viral life cycles as compared to the spatial distribution of the lipid. Various routes of cholesterol trafficking were found to be hijacked in viral infections with respect to organelle-endosome contact sites mediating cholesterol shuttling. Thus, re-distribution of cellular cholesterol in the context of viral infections requires more attention in ongoing research. As a final aim, a pan-antiviral treatment could be found just within the transport and re-adjustment of local cholesterol concentrations. Thus, we aimed to emphasize the importance of the regulatory roles the endosomal system fulfils herein and hope to stimulate research in this field.
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Affiliation(s)
| | - Eberhard Hildt
- Department of Virology, Paul-Ehrlich-Institute, Langen, Germany
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