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Krogman WL, Woodard T, McKay RSF. Anesthetic Mechanisms: Synergistic Interactions With Lipid Rafts and Voltage-Gated Sodium Channels. Anesth Analg 2024; 139:92-106. [PMID: 37968836 DOI: 10.1213/ane.0000000000006738] [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: 11/17/2023]
Abstract
Despite successfully utilizing anesthetics for over 150 years, the mechanism of action remains relatively unknown. Recent studies have shown promising results, but due to the complex interactions between anesthetics and their targets, there remains a clear need for further mechanistic research. We know that lipophilicity is directly connected to anesthetic potency since lipid solubility relates to anesthetic partition into the membrane. However, clinically relevant concentrations of anesthetics do not significantly affect lipid bilayers but continue to influence various molecular targets. Lipid rafts are derived from liquid-ordered phases of the plasma membrane that contain increased concentrations of cholesterol and sphingomyelin and act as staging platforms for membrane proteins, including ion channels. Although anesthetics do not perturb membranes at clinically relevant concentrations, they have recently been shown to target lipid rafts. In this review, we summarize current research on how different types of anesthetics-local, inhalational, and intravenous-bind and affect both lipid rafts and voltage-gated sodium channels, one of their major targets, and how those effects synergize to cause anesthesia and analgesia. Local anesthetics block voltage-gated sodium channel pores while also disrupting lipid packing in ordered membranes. Inhalational anesthetics bind to the channel pore and the voltage-sensing domain while causing an increase in the number, size, and diameter of lipid rafts. Intravenous anesthetics bind to the channel primarily at the voltage-sensing domain and the selectivity filter, while causing lipid raft perturbation. These changes in lipid nanodomain structure possibly give proteins access to substrates that have translocated as a result of these structural alterations, resulting in lipid-driven anesthesia. Overall, anesthetics can impact channel activity either through direct interaction with the channel, indirectly through the lipid raft, or both. Together, these result in decreased sodium ion flux into the cell, disrupting action potentials and producing anesthetic effects. However, more research is needed to elucidate the indirect mechanisms associated with channel disruption through the lipid raft, as not much is known about anionic lipid products and their influence over voltage-gated sodium channels. Anesthetics' effect on S-palmitoylation, a promising mechanism for direct and indirect influence over voltage-gated sodium channels, is another auspicious avenue of research. Understanding the mechanisms of different types of anesthetics will allow anesthesiologists greater flexibility and more specificity when treating patients.
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Affiliation(s)
- William L Krogman
- From the Department of Anesthesiology, University of Kansas School of Medicine - Wichita, Wichita, Kansas
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2
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Grewal T, Nguyen MKL, Buechler C. Cholesterol and COVID-19-therapeutic opportunities at the host/virus interface during cell entry. Life Sci Alliance 2024; 7:e202302453. [PMID: 38388172 PMCID: PMC10883773 DOI: 10.26508/lsa.202302453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/24/2024] Open
Abstract
The rapid development of vaccines to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections has been critical to reduce the severity of COVID-19. However, the continuous emergence of new SARS-CoV-2 subtypes highlights the need to develop additional approaches that oppose viral infections. Targeting host factors that support virus entry, replication, and propagation provide opportunities to lower SARS-CoV-2 infection rates and improve COVID-19 outcome. This includes cellular cholesterol, which is critical for viral spike proteins to capture the host machinery for SARS-CoV-2 cell entry. Once endocytosed, exit of SARS-CoV-2 from the late endosomal/lysosomal compartment occurs in a cholesterol-sensitive manner. In addition, effective release of new viral particles also requires cholesterol. Hence, cholesterol-lowering statins, proprotein convertase subtilisin/kexin type 9 antibodies, and ezetimibe have revealed potential to protect against COVID-19. In addition, pharmacological inhibition of cholesterol exiting late endosomes/lysosomes identified drug candidates, including antifungals, to block SARS-CoV-2 infection. This review describes the multiple roles of cholesterol at the cell surface and endolysosomes for SARS-CoV-2 entry and the potential of drugs targeting cholesterol homeostasis to reduce SARS-CoV-2 infectivity and COVID-19 disease severity.
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Affiliation(s)
- Thomas Grewal
- https://ror.org/0384j8v12 School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Mai Khanh Linh Nguyen
- https://ror.org/0384j8v12 School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Christa Buechler
- https://ror.org/01226dv09 Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
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3
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Petersen EN, Pavel MA, Hansen SS, Gudheti M, Wang H, Yuan Z, Murphy KR, Ja W, Ferris HA, Jorgensen E, Hansen SB. Mechanical activation of TWIK-related potassium channel by nanoscopic movement and rapid second messenger signaling. eLife 2024; 12:RP89465. [PMID: 38407149 PMCID: PMC10942622 DOI: 10.7554/elife.89465] [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] [Indexed: 02/27/2024] Open
Abstract
Rapid conversion of force into a biological signal enables living cells to respond to mechanical forces in their environment. The force is believed to initially affect the plasma membrane and then alter the behavior of membrane proteins. Phospholipase D2 (PLD2) is a mechanosensitive enzyme that is regulated by a structured membrane-lipid site comprised of cholesterol and saturated ganglioside (GM1). Here we show stretch activation of TWIK-related K+ channel (TREK-1) is mechanically evoked by PLD2 and spatial patterning involving ordered GM1 and 4,5-bisphosphate (PIP2) clusters in mammalian cells. First, mechanical force deforms the ordered lipids, which disrupts the interaction of PLD2 with the GM1 lipids and allows a complex of TREK-1 and PLD2 to associate with PIP2 clusters. The association with PIP2 activates the enzyme, which produces the second messenger phosphatidic acid (PA) that gates the channel. Co-expression of catalytically inactive PLD2 inhibits TREK-1 stretch currents in a biological membrane. Cellular uptake of cholesterol inhibits TREK-1 currents in culture and depletion of cholesterol from astrocytes releases TREK-1 from GM1 lipids in mouse brain. Depletion of the PLD2 ortholog in flies results in hypersensitivity to mechanical force. We conclude PLD2 mechanosensitivity combines with TREK-1 ion permeability to elicit a mechanically evoked response.
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Affiliation(s)
- E Nicholas Petersen
- Departments of Molecular Medicine, The Scripps Research Institute, ScrippsJupiterUnited States
- Scripps Research Skaggs Graduate School of Chemical and Biological Science, The Scripps Research Institute, Scripps,JupiterUnited States
| | - Mahmud Arif Pavel
- Departments of Molecular Medicine, The Scripps Research Institute, ScrippsJupiterUnited States
| | - Samuel S Hansen
- Departments of Molecular Medicine, The Scripps Research Institute, ScrippsJupiterUnited States
| | - Manasa Gudheti
- Division of Endocrinology and Metabolism, Center for Brain Immunology and Glia, Department of Neuroscience, University of VirginiaCharlottesvilleUnited States
| | - Hao Wang
- Departments of Molecular Medicine, The Scripps Research Institute, ScrippsJupiterUnited States
- Scripps Research Skaggs Graduate School of Chemical and Biological Science, The Scripps Research Institute, Scripps,JupiterUnited States
| | - Zixuan Yuan
- Departments of Molecular Medicine, The Scripps Research Institute, ScrippsJupiterUnited States
- Scripps Research Skaggs Graduate School of Chemical and Biological Science, The Scripps Research Institute, Scripps,JupiterUnited States
| | - Keith R Murphy
- Department of Neuroscience, The Scripps Research Institute, ScrippsJupiterUnited States
- Center on Aging,The Scripps Research Institute, ScrippsJupiterUnited States
| | - William Ja
- Department of Neuroscience, The Scripps Research Institute, ScrippsJupiterUnited States
- Center on Aging,The Scripps Research Institute, ScrippsJupiterUnited States
| | - Heather A Ferris
- Division of Endocrinology and Metabolism, Center for Brain Immunology and Glia, Department of Neuroscience, University of VirginiaCharlottesvilleUnited States
| | - Erik Jorgensen
- Department of Biology, Howard Hughes Medical Institute, University of UtahSalt Lake CityUnited States
| | - Scott B Hansen
- Departments of Molecular Medicine, The Scripps Research Institute, ScrippsJupiterUnited States
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4
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Roy AV, Chan M, Banadyga L, He S, Zhu W, Chrétien M, Mbikay M. Quercetin inhibits SARS-CoV-2 infection and prevents syncytium formation by cells co-expressing the viral spike protein and human ACE2. Virol J 2024; 21:29. [PMID: 38273400 PMCID: PMC10811921 DOI: 10.1186/s12985-024-02299-w] [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: 11/20/2023] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Several in silico studies have determined that quercetin, a plant flavonol, could bind with strong affinity and low free energy to SARS-CoV-2 proteins involved in viral entry and replication, suggesting it could block infection of human cells by the virus. In the present study, we examined the ex vivo ability of quercetin to inhibit of SARS-CoV-2 replication and explored the mechanisms of this inhibition. METHODS Green monkey kidney Vero E6 cells and in human colon carcinoma Caco-2 cells were infected with SARS-CoV-2 and incubated in presence of quercetin; the amount of replicated viral RNA was measured in spent media by RT-qPCR. Since the formation of syncytia is a mechanism of SARS-CoV-2 propagation, a syncytialization model was set up using human embryonic kidney HEK293 co-expressing SARS-CoV-2 Spike (S) protein and human angiotensin converting enzyme 2 (ACE2), [HEK293(S + ACE2) cells], to assess the effect of quercetin on this cytopathic event by microscopic imaging and protein immunoblotting. RESULTS Quercetin inhibited SARS-CoV-2 replication in Vero E6 cells and Caco-2 cells in a concentration-dependent manner with a half inhibitory concentration (IC50) of 166.6 and 145.2 µM, respectively. It also inhibited syncytialization of HEK293(S + ACE2) cells with an IC50 of 156.7 µM. Spike and ACE2 co-expression was associated with decreased expression, increased proteolytic processing of the S protein, and diminished production of the fusogenic S2' fragment of S. Furin, a proposed protease for this processing, was inhibited by quercetin in vitro with an IC50 of 116 µM. CONCLUSION These findings suggest that at low 3-digit micromolar concentrations of quercetin could impair SARS-CoV-2 infection of human cells partly by blocking the fusion process that promotes its propagation.
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Affiliation(s)
- Annie V Roy
- Functional Endoproteolysis Laboratory, Montreal Clinical Research Institute, Montreal, QC, Canada
| | - Michael Chan
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Logan Banadyga
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada
| | - Shihua He
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Wenjun Zhu
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
- National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB, Canada
| | - Michel Chrétien
- Functional Endoproteolysis Laboratory, Montreal Clinical Research Institute, Montreal, QC, Canada
| | - Majambu Mbikay
- Functional Endoproteolysis Laboratory, Montreal Clinical Research Institute, Montreal, QC, Canada.
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Hulscher N, Procter BC, Wynn C, McCullough PA. Clinical Approach to Post-acute Sequelae After COVID-19 Infection and Vaccination. Cureus 2023; 15:e49204. [PMID: 38024037 PMCID: PMC10663976 DOI: 10.7759/cureus.49204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2023] [Indexed: 12/01/2023] Open
Abstract
The spike protein of SARS-CoV-2 has been found to exhibit pathogenic characteristics and be a possible cause of post-acute sequelae after SARS-CoV-2 infection or COVID-19 vaccination. COVID-19 vaccines utilize a modified, stabilized prefusion spike protein that may share similar toxic effects with its viral counterpart. The aim of this study is to investigate possible mechanisms of harm to biological systems from SARS-CoV-2 spike protein and vaccine-encoded spike protein and to propose possible mitigation strategies. We searched PubMed, Google Scholar, and 'grey literature' to find studies that (1) investigated the effects of the spike protein on biological systems, (2) helped differentiate between viral and vaccine-generated spike proteins, and (3) identified possible spike protein detoxification protocols and compounds that had signals of benefit and acceptable safety profiles. We found abundant evidence that SARS-CoV-2 spike protein may cause damage in the cardiovascular, hematological, neurological, respiratory, gastrointestinal, and immunological systems. Viral and vaccine-encoded spike proteins have been shown to play a direct role in cardiovascular and thrombotic injuries from both SARS-CoV-2 and vaccination. Detection of spike protein for at least 6-15 months after vaccination and infection in those with post-acute sequelae indicates spike protein as a possible primary contributing factor to long COVID. We rationalized that these findings give support to the potential benefit of spike protein detoxification protocols in those with long-term post-infection and/or vaccine-induced complications. We propose a base spike detoxification protocol, composed of oral nattokinase, bromelain, and curcumin. This approach holds immense promise as a base of clinical care, upon which additional therapeutic agents are applied with the goal of aiding in the resolution of post-acute sequelae after SARS-CoV-2 infection and COVID-19 vaccination. Large-scale, prospective, randomized, double-blind, placebo-controlled trials are warranted in order to determine the relative risks and benefits of the base spike detoxification protocol.
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Affiliation(s)
- Nicolas Hulscher
- Epidemiology, Unversity of Michigan School of Public Health, Ann Arbor, USA
| | | | - Cade Wynn
- Family Medicine, McKinney Family Medicine, McKinney, USA
| | - Peter A McCullough
- Internal Medicine, Cardiology, McKinney Family Medicine, McKinney, USA
- Cardiology, Epidemiology, and Public Health, McCullough Foundation, Dallas, USA
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Call IM, Bois JL, Hansen SB. Super-resolution imaging of potassium channels with genetically encoded EGFP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.13.561998. [PMID: 37873307 PMCID: PMC10592817 DOI: 10.1101/2023.10.13.561998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The plasma membrane is a well-organized structure of lipids and proteins, segmented into lipid compartments under 200 nm in size. This specific spatial patterning is crucial for the function of proteins and necessitates super-resolution imaging for its elucidation. Here, we establish that the genetically encoded enhanced green fluorescent protein (EGFP), when combined with direct optical reconstruction microscopy (dSTORM), tracks shear- and cholesterol-induced nanoscopic patterning of potassium channels overexpressed in HEK293T cells. Leveraging EGFP in dSTORM (EGFP-STORM), our findings indicate that cholesterol directs the C-terminus of TWIK-related potassium channel (TREK-1) to ceramide-enriched lipid ganglioside (GM1) clusters. In the absence of the C-terminus, the channel associates with phosphatidylinositol 4,5-bisphosphate (PIP2) cluster. Similarly, cholesterol derived from astrocytes repositions EGFP-tagged inward-rectifying potassium (Kir) channels into GM1 clusters. Without cholesterol, the channel aligns with PIP2 lipids. We deduce that cholesterol's interaction with Kir sequesters the channel, separating it from its activating lipid PIP2. Fundamentally, a genetically encoded EGFP tag should make any protein amenable to dSTORM analysis.
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Affiliation(s)
- Isabelle M. Call
- Departments of Molecular Medicine, UF Scripps, Jupiter Florida 33458, USA
- Department of Neuroscience, UF Scripps, Jupiter Florida 33458, USA
- Department of Biology, Brigham Young University-Idaho; Rexburg ID 83440, USA
| | - Julian L. Bois
- Departments of Molecular Medicine, UF Scripps, Jupiter Florida 33458, USA
- Department of Neuroscience, UF Scripps, Jupiter Florida 33458, USA
| | - Scott B. Hansen
- Departments of Molecular Medicine, UF Scripps, Jupiter Florida 33458, USA
- Department of Neuroscience, UF Scripps, Jupiter Florida 33458, USA
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7
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Pappa M, Panagiotopoulos A, Thomas K, Fanouriakis A. Systemic Lupus Erythematosus and COVID-19. Curr Rheumatol Rep 2023; 25:192-203. [PMID: 37477841 PMCID: PMC10504107 DOI: 10.1007/s11926-023-01110-z] [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] [Accepted: 06/28/2023] [Indexed: 07/22/2023]
Abstract
PURPOSE OF REVIEW To describe the current state of knowledge regarding COVID-19 in patients with systemic lupus erythematosus (SLE). We focus on (i) SARS-CoV-2 vaccination uptake, immunogenicity and safety, and (ii) outcomes of COVID-19 in patients with SLE and pertinent risk factors for adverse sequelae. RECENT FINDINGS Notwithstanding the potential concern of patients about possible post-vaccination side-effects, the safety of anti-SARS-CoV-2 vaccines in patients with SLE has been undisputedly confirmed in numerous studies. Humoral immunogenicity is generally attained in SLE, although affected by the use of background immunosuppressive drugs, especially rituximab. The latter has also clearly been implicated with adverse COVID-19 outcomes in SLE, including need for hospitalization, mechanical ventilation and death. Although the wide adoption of vaccination has significantly improved COVID-19 outcomes, patients with SLE continue to pose challenges during the pandemic, mainly owing to administered immunosuppressive medications.
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Affiliation(s)
- Maria Pappa
- 1st Department of Propaedeutic Internal Medicine, Medical School National and Kapodistrian University of Athens, Athens, Greece
| | - Alexandros Panagiotopoulos
- 1st Department of Propaedeutic Internal Medicine, Medical School National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos Thomas
- 4th Department of Internal Medicine, "Attikon" University Hospital, Medical School National and Kapodistrian University of Athens, Athens, Greece
| | - Antonis Fanouriakis
- Rheumatology and Clinical Immunology, "Attikon" University Hospital of Athens, Medical School National and Kapodistrian University of Athens, Athens, Greece.
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8
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Lin DSH, Tzeng SC, Cha TL, Hung CM, Lin WC, Yang CM, Lu HY, Chang JY, Huang SW. Inhalable chitosan-based hydrogel as a mucosal adjuvant for hydroxychloroquine in the treatment for SARS-CoV-2 infection in a hamster model. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2023; 56:951-960. [PMID: 37620239 DOI: 10.1016/j.jmii.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 04/20/2023] [Accepted: 08/04/2023] [Indexed: 08/26/2023]
Abstract
BACKGROUND Effective therapy for COVID-19 remains limited. Hydroxychloroquine (HCQ) has been considered, but safety and efficacy concerns remain. Chitosan exhibits antiviral and immunomodulatory effects, yet how the combination of HCQ and chitosan performs in treating COVID-19 is unknown. METHODS Male Syrian hamsters were inoculated intranasally with standardized stocks of the SARS-CoV-2 virus. Hamsters were allocated to saline (PBS), chitosan oligosaccharide (COS), HCQ, or COS + HCQ groups and received corresponding drugs. On days 1, 7, and 14 post-infection, two animals from each group were euthanized for sample collection. Viral loads were measured in lung homogenates. Biochemistry markers, cytokines, and immunoglobulins were analyzed from hamster sera. HCQ concentrations were compared between the blood, bronchoalveolar lavage, and lung tissues. All groups underwent histopathology exams of the lungs. Additional hamsters were treated with the same drugs to assess for toxicities to the heart and liver. RESULTS Among all groups, viral loads in the COS + HCQ group were the lowest by day 8. The COS + HCQ group produced the highest interleukin (IL)-6 levels on day 4, and the highest IL-10, IgA and IgG levels on day 8. HCQ concentrations were higher in the COS + HCQ group's lungs than the HCQ group, despite having received half the dose of HCQ. Histopathology demonstrated earlier inflammation resolution and swifter viral clearance in the COS + HCQ group. There was no evidence of cardiac or hepatic injury in hamsters that received HCQ. CONCLUSION In hamsters infected with the SARS-CoV-2 virus, the combination of intranasal COS and HCQ was associated with increased HCQ absorption in the lungs, more effective immune responses, without increasing the risk of hepatic or cardiac injuries.
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Affiliation(s)
- Donna Shu-Han Lin
- Division of Cardiology, Department of Internal Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Shian Chiuan Tzeng
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
| | - Tai-Lung Cha
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Chin-Mao Hung
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Chin Lin
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan; Department of Pathology and Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Chuen-Mi Yang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Hsuan-Ying Lu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Jia-Yu Chang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Shu-Wei Huang
- Department of Orthopedics, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
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Vanderlinden E, Boonen A, Noppen S, Schoofs G, Imbrechts M, Geukens N, Snoeck R, Stevaert A, Naesens L, Andrei G, Schols D. PRO-2000 exhibits SARS-CoV-2 antiviral activity by interfering with spike-heparin binding. Antiviral Res 2023; 217:105700. [PMID: 37562608 DOI: 10.1016/j.antiviral.2023.105700] [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: 06/02/2023] [Revised: 07/29/2023] [Accepted: 08/06/2023] [Indexed: 08/12/2023]
Abstract
Here, we report on the anti-SARS-CoV-2 activity of PRO-2000, a sulfonated polyanionic compound. In Vero cells infected with the Wuhan, alpha, beta, delta or omicron variant, PRO-2000 displayed EC50 values of 1.1 μM, 2.4 μM, 1.3 μM, 2.1 μM and 0.11 μM, respectively, and an average selectivity index (i.e. ratio of cytotoxic versus antiviral concentration) of 172. Its anti-SARS-CoV-2 activity was confirmed by virus yield assays in Vero cells, Caco2 cells and A549 cells overexpressing ACE2 and TMPRSS2 (A549-AT). Using pseudoviruses bearing the SARS-CoV-2 spike (S), PRO-2000 was shown to block the S-mediated pseudovirus entry in Vero cells and A549-AT cells, with EC50 values of 0.091 μM and 1.6 μM, respectively. This entry process is initiated by interaction of the S glycoprotein with angiotensin-converting enzyme 2 (ACE2) and heparan sulfate proteoglycans. Surface Plasmon Resonance (SPR) studies showed that PRO-2000 binds to the receptor-binding domain (RBD) of S with a KD of 1.6 nM. Similar KD values (range: 1.2 nM-2.1 nM) were obtained with the RBDs of the alpha, beta, delta and omicron variants. In an SPR neutralization assay, PRO-2000 had no effect on the interaction between the RBD and ACE2. Instead, PRO-2000 was proven to inhibit binding of the RBD to a heparin-coated sensor chip, yielding an IC50 of 1.1 nM. To conclude, PRO-2000 has the potential to inhibit a broad range of SARS-CoV-2 variants by blocking the heparin-binding site on the S protein.
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Affiliation(s)
- Evelien Vanderlinden
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium.
| | - Arnaud Boonen
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Sam Noppen
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Geert Schoofs
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Maya Imbrechts
- PharmAbs, The KU Leuven Antibody Center, Herestraat 49 box 820, 3000, Leuven, Belgium
| | - Nick Geukens
- PharmAbs, The KU Leuven Antibody Center, Herestraat 49 box 820, 3000, Leuven, Belgium
| | - Robert Snoeck
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Annelies Stevaert
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Lieve Naesens
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Graciela Andrei
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
| | - Dominique Schols
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000, Leuven, Belgium
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10
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Hansen SB, Wang H. The shared role of cholesterol in neuronal and peripheral inflammation. Pharmacol Ther 2023; 249:108486. [PMID: 37390970 DOI: 10.1016/j.pharmthera.2023.108486] [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: 03/17/2023] [Revised: 06/22/2023] [Accepted: 06/27/2023] [Indexed: 07/02/2023]
Abstract
Neurodegeneration and its loss of cognitive function is associated with inflammation and an accumulation of lipids. In the periphery, cholesterol's uptake drives a major component of chronic inflammation. In this perspective, we describe the cellular and molecular roles of cholesterol in neuroinflammation and contrast them with those in the periphery. Incorporating shared mechanisms from the periphery, cholesterol emerges as a central signal originating in astrocytes and connecting inflammatory escalation in neurons and microglia. A cholesterol uptake pathway is proposed for neuroinflammation, and we speculate on the binding of cholesterol transport protein apolipoprotein E (apoE), including the Christchurch mutant (R136S), to cell surface receptors as a potential protective modality against uptake of astrocyte cholesterol and escalated neuroinflammation. Lastly, we discuss the molecular basis of cholesterol signaling through nanoscopic clustering and peripheral sources of cholesterol after opening of the blood brain barrier.
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Affiliation(s)
- Scott B Hansen
- Department of Molecular Medicine, UF Scripps, Jupiter, FL 33458, USA; Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA.
| | - Hao Wang
- The Scripps Research Institute, Jupiter, FL 33458, USA
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11
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Ren M, Ma Z, Zhao L, Wang Y, An H, Sun F. Self-Association of ACE-2 with Different RBD Amounts: A Dynamic Simulation Perspective on SARS-CoV-2 Infection. J Chem Inf Model 2023; 63:4423-4432. [PMID: 37382878 DOI: 10.1021/acs.jcim.3c00041] [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: 06/30/2023]
Abstract
Transmissibility of SARS-CoV-2 initially relies on its trimeric Spike-RBDs to tether the ACE-2 on host cells, and enhanced self-association of ACE-2 engaged with Spike facilitates the viral infection. Two primary packing modes of Spike-ACE2 heteroproteins exist potentially due to discrepant amounts of RBDs loading on ACE-2, but the resultant self-association difference is inherently unclear. We used extensive coarse-grained dynamic simulations to characterize the self-association efficiency, the conformation relevance, and the molecular mechanism of ACE-2 with different RBD amounts. It was revealed that the ACE-2 hanging two/full RBDs (Mode-A) rapidly dimerized into the heteroprotein complex in a compact "linear" conformation, while the bare ACE-2 showed weakened self-association and a protein complex. The RBD-tethered ectodomains of ACE-2 presented a more upright conformation relative to the membrane, and the intermolecular ectodomains were predominantly packed by the neck domains, which was obligated to the rapid protein self-association in a compact pattern. Noted is the fact that the ACE-2 tethered by a single RBD (Mode-B) retained considerable self-association efficiency and clustering capability, which unravels the interrelation of ACE-2 colocalization and protein cross-linkage. The molecular perspectives in this study expound the self-association potency of ACE-2 with different RBD amounts and the viral activity implications, which can greatly enhance our comprehension of SARS-CoV-2 infection details.
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Affiliation(s)
- Meina Ren
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Health Science & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Ziyi Ma
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Health Science & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Lina Zhao
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Health Science & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Yanjiao Wang
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Health Science & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Hailong An
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Health Science & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Fude Sun
- Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Health Science & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
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12
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Wing PAC, Schmidt NM, Peters R, Erdmann M, Brown R, Wang H, Swadling L, Newman J, Thakur N, Shionoya K, Morgan SB, Hinks TSC, Watashi K, Bailey D, Hansen SB, Davidson AD, Maini MK, McKeating JA. An ACAT inhibitor suppresses SARS-CoV-2 replication and boosts antiviral T cell activity. PLoS Pathog 2023; 19:e1011323. [PMID: 37134108 PMCID: PMC10202285 DOI: 10.1371/journal.ppat.1011323] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 05/22/2023] [Accepted: 03/27/2023] [Indexed: 05/04/2023] Open
Abstract
The severity of disease following infection with SARS-CoV-2 is determined by viral replication kinetics and host immunity, with early T cell responses and/or suppression of viraemia driving a favourable outcome. Recent studies uncovered a role for cholesterol metabolism in the SARS-CoV-2 life cycle and in T cell function. Here we show that blockade of the enzyme Acyl-CoA:cholesterol acyltransferase (ACAT) with Avasimibe inhibits SARS-CoV-2 pseudoparticle infection and disrupts the association of ACE2 and GM1 lipid rafts on the cell membrane, perturbing viral attachment. Imaging SARS-CoV-2 RNAs at the single cell level using a viral replicon model identifies the capacity of Avasimibe to limit the establishment of replication complexes required for RNA replication. Genetic studies to transiently silence or overexpress ACAT isoforms confirmed a role for ACAT in SARS-CoV-2 infection. Furthermore, Avasimibe boosts the expansion of functional SARS-CoV-2-specific T cells from the blood of patients sampled during the acute phase of infection. Thus, re-purposing of ACAT inhibitors provides a compelling therapeutic strategy for the treatment of COVID-19 to achieve both antiviral and immunomodulatory effects. Trial registration: NCT04318314.
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Affiliation(s)
- Peter A. C. Wing
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nathalie M. Schmidt
- Division of Infection and Immunity and Institute of Immunity and Transplantation, UCL, London, United Kingdom
| | - Rory Peters
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Maximilian Erdmann
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Rachel Brown
- Division of Infection and Immunity and Institute of Immunity and Transplantation, UCL, London, United Kingdom
- UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Hao Wang
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, San Diego, California, United States of America
- Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, San Diego, California, United States of America
| | - Leo Swadling
- Division of Infection and Immunity and Institute of Immunity and Transplantation, UCL, London, United Kingdom
| | | | | | | | - Kaho Shionoya
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Applied Biological Science, Tokyo University of Science, Noda, Japan
- Research Centre for Drug and Vaccine Development, National Institute of Infectious Diseases, Tokyo, Japan
| | - Sophie B. Morgan
- Respiratory Medicine Unit and National Institute for Health Research Oxford Biomedical Research Centre, Nuffield Department of Medicine, Experimental Medicine, University of Oxford, Oxford, United Kingdom
| | - Timothy SC Hinks
- Respiratory Medicine Unit and National Institute for Health Research Oxford Biomedical Research Centre, Nuffield Department of Medicine, Experimental Medicine, University of Oxford, Oxford, United Kingdom
| | - Koichi Watashi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Applied Biological Science, Tokyo University of Science, Noda, Japan
- Research Centre for Drug and Vaccine Development, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Scott B. Hansen
- UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Andrew D. Davidson
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Mala K. Maini
- Division of Infection and Immunity and Institute of Immunity and Transplantation, UCL, London, United Kingdom
| | - Jane A. McKeating
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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13
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Toussi SS, Hammond JL, Gerstenberger BS, Anderson AS. Therapeutics for COVID-19. Nat Microbiol 2023; 8:771-786. [PMID: 37142688 DOI: 10.1038/s41564-023-01356-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 03/09/2023] [Indexed: 05/06/2023]
Abstract
Vaccines and monoclonal antibody treatments to prevent severe coronavirus disease 2019 (COVID-19) illness were available within a year of the pandemic being declared but there remained an urgent need for therapeutics to treat patients who were not vaccinated, were immunocompromised or whose vaccine immunity had waned. Initial results for investigational therapies were mixed. AT-527, a repurposed nucleoside inhibitor for hepatitis C virus, enabled viral load reduction in a hospitalized cohort but did not reduce viral load in outpatients. The nucleoside inhibitor molnupiravir prevented death but failed to prevent hospitalization. Nirmatrelvir, an inhibitor of the main protease (Mpro), co-dosed with the pharmacokinetic booster ritonavir, reduced hospitalization and death. Nirmatrelvir-ritonavir and molnupiravir received an Emergency Use Authorization in the United States at the end of 2021. Immunomodulatory drugs such as baricitinib, tocilizumab and corticosteroid, which target host-driven COVID-19 symptoms, are also in use. We highlight the development of COVID-19 therapies and the challenges that remain for anticoronavirals.
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14
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Wang H, Yuan Z, Pavel MA, Jablonski SM, Jablonski J, Hobson R, Valente S, Reddy CB, Hansen SB. The role of high cholesterol in SARS-CoV-2 infectivity. J Biol Chem 2023:104763. [PMID: 37119851 PMCID: PMC10140059 DOI: 10.1016/j.jbc.2023.104763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/11/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023] Open
Abstract
Coronavirus disease 2019 (COVID19) is a respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus binds to angiotensinogen converting enzyme 2 (ACE2) which mediates viral entry into mammalian cells. COVID19 is notably severe in elderly and those with underlying chronic conditions. The cause of selective severity is not well understood. Here we show cholesterol and the signaling lipid phosphatidyl-inositol 4,5 bisphosphate (PIP2) regulate viral infectivity through the localization of ACE2's into nanoscopic (<200 nm) lipid clusters. Uptake of cholesterol into cell membranes (a condition common to chronic disease) causes ACE2 to move from PIP2 lipids to endocytic ganglioside (GM1) lipids, where the virus is optimally located for viral entry. In mice, age, and high fat diet increase lung tissue cholesterol by up to 40%. And in smokers with chronic disease, cholesterol is elevated two-fold, a magnitude of change that dramatically increases infectivity of virus in cell culture. We conclude increasing the ACE2 location near endocytic lipids increases viral infectivity and may help explain the selective severity of COVID-19 in aged and diseased populations.
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Affiliation(s)
- Hao Wang
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, 33458, USA; Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Zixuan Yuan
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, 33458, USA; Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Mahmud Arif Pavel
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | | | - Joseph Jablonski
- Department of Immunology and Virology, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Robert Hobson
- Bruker Nano Surfaces, Fitchburg, WI, 53711, USA; Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Susana Valente
- Department of Immunology and Virology, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Chakravarthy B Reddy
- Department of Internal Medicine, University of Utah Health Sciences Center, Salt Lake City, UT, 84112, USA
| | - Scott B Hansen
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, 33458, USA.
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15
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Hansen SB, Yuan Z. Getting in on the action: New tools to see SARS-CoV-2 infect a cell. Cell Chem Biol 2023; 30:233-234. [PMID: 36931249 PMCID: PMC10018748 DOI: 10.1016/j.chembiol.2023.02.010] [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: 03/18/2023]
Abstract
In this issue of Cell Chemical Biology, Miao et al. develop probes for live cell tracking of SARS-CoV-2. The probes reveal the endocytic pathway for viral entry. Unexpectedly, the antiviral compound BafA1 traps the virus on the cell surface, highlighting the power of super-resolution imaging in live cells.
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Affiliation(s)
- Scott B Hansen
- Department of Molecular Medicine, UF Scripps, Jupiter, FL 33458, USA; Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA.
| | - Zixuan Yuan
- Department of Molecular Medicine, UF Scripps, Jupiter, FL 33458, USA; Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA; Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL 33458, USA
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16
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Miao L, Yan C, Chen Y, Zhou W, Zhou X, Qiao Q, Xu Z. SIM imaging resolves endocytosis of SARS-CoV-2 spike RBD in living cells. Cell Chem Biol 2023; 30:248-260.e4. [PMID: 36889309 PMCID: PMC9990177 DOI: 10.1016/j.chembiol.2023.02.001] [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: 07/15/2022] [Revised: 01/05/2023] [Accepted: 02/03/2023] [Indexed: 03/09/2023]
Abstract
It is urgent to understand the infection mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the prevention and treatment of COVID-19. The infection of SARS-CoV-2 starts when the receptor-binding domain (RBD) of viral spike protein binds to angiotensin-converting enzyme 2 (ACE2) of the host cell, but the endocytosis details after this binding are not clear. Here, RBD and ACE2 were genetically coded and labeled with organic dyes to track RBD endocytosis in living cells. The photostable dyes enable long-term structured illumination microscopy (SIM) imaging and to quantify RBD-ACE2 binding (RAB) by the intensity ratio of RBD/ACE2 fluorescence. We resolved RAB endocytosis in living cells, including RBD-ACE2 recognition, cofactor-regulated membrane internalization, RAB-bearing vesicle formation and transport, RAB degradation, and downregulation of ACE2. The RAB was found to activate the RBD internalization. After vesicles were transported and matured within cells, RAB was finally degraded after being taken up by lysosomes. This strategy is a promising tool to understand the infection mechanism of SARS-CoV-2.
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Affiliation(s)
- Lu Miao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Chunyu Yan
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China; Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116012, China
| | - Yingzhu Chen
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Wei Zhou
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China; Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116012, China
| | - Xuelian Zhou
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China; Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116012, China
| | - Qinglong Qiao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zhaochao Xu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China; Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116012, China.
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17
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Yuan Z, Hansen SB. Cholesterol Regulation of Membrane Proteins Revealed by Two-Color Super-Resolution Imaging. MEMBRANES 2023; 13:membranes13020250. [PMID: 36837753 PMCID: PMC9966874 DOI: 10.3390/membranes13020250] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 05/15/2023]
Abstract
Cholesterol and phosphatidyl inositol 4,5-bisphosphate (PIP2) are hydrophobic molecules that regulate protein function in the plasma membrane of all cells. In this review, we discuss how changes in cholesterol concentration cause nanoscopic (<200 nm) movements of membrane proteins to regulate their function. Cholesterol is known to cluster many membrane proteins (often palmitoylated proteins) with long-chain saturated lipids. Although PIP2 is better known for gating ion channels, in this review, we will discuss a second independent function as a regulator of nanoscopic protein movement that opposes cholesterol clustering. The understanding of the movement of proteins between nanoscopic lipid domains emerged largely through the recent advent of super-resolution imaging and the establishment of two-color techniques to label lipids separate from proteins. We discuss the labeling techniques for imaging, their strengths and weakness, and how they are used to reveal novel mechanisms for an ion channel, transporter, and enzyme function. Among the mechanisms, we describe substrate and ligand presentation and their ability to activate enzymes, gate channels, and transporters rapidly and potently. Finally, we define cholesterol-regulated proteins (CRP) and discuss the role of PIP2 in opposing the regulation of cholesterol, as seen through super-resolution imaging.
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Affiliation(s)
- Zixuan Yuan
- Department of Molecular Medicine, Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA
- Department of Neuroscience UF Scripps, Jupiter, FL 33458, USA
- Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Scott B. Hansen
- Department of Molecular Medicine, Department of Neuroscience, UF Scripps, Jupiter, FL 33458, USA
- Department of Neuroscience UF Scripps, Jupiter, FL 33458, USA
- Correspondence:
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