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Cleary SJ, Seo Y, Tian JJ, Kwaan N, Bulkley DP, Bentlage AEH, Vidarsson G, Boilard É, Spirig R, Zimring JC, Looney MR. IgG hexamers initiate complement-dependent acute lung injury. J Clin Invest 2024:e178351. [PMID: 38530369 DOI: 10.1172/jci178351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024] Open
Abstract
Antibodies can initiate lung injury in a variety of disease states such as autoimmunity, transfusion reactions, or after organ transplantation, but the key factors determining in vivo pathogenicity of injury-inducing antibodies are unclear. Harmful antibodies often activate the complement cascade. A model for how IgG antibodies trigger complement activation involves interactions between IgG Fc domains driving assembly of IgG hexamer structures that activate C1 complexes. The importance of IgG hexamers in initiating injury responses was unclear, so we tested their relevance in a mouse model of alloantibody and complement-mediated acute lung injury. We used three approaches to block alloantibody hexamerization (antibody carbamylation, the K439E Fc mutation, or treatment with domain B from Staphylococcal protein A), all of which reduced acute lung injury. Conversely, Fc mutations promoting spontaneous hexamerization made a harmful alloantibody into a more potent inducer of acute lung injury and rendered an innocuous alloantibody pathogenic. Treatment with a recombinant Fc hexamer 'decoy' therapeutic protected mice from lung injury, including in a model with transgenic human FCGR2A expression that exacerbated pathology. These results indicate an in vivo role of IgG hexamerization in initiating acute lung injury and the potential for therapeutics that inhibit or mimic hexamerization to treat antibody-mediated diseases.
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Affiliation(s)
- Simon J Cleary
- Department of Medicine, UCSF, San Francisco, United States of America
| | - Yurim Seo
- Department of Medicine, UCSF, San Francisco, United States of America
| | - Jennifer J Tian
- Department of Medicine, UCSF, San Francisco, United States of America
| | - Nicholas Kwaan
- Department of Medicine, UCSF, San Francisco, United States of America
| | - David P Bulkley
- Department of Biochemistry and Biophysics, UCSF, San Francisco, United States of America
| | - Arthur E H Bentlage
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, Netherlands
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, Netherlands
| | - Éric Boilard
- Infectious and Immune Diseases, Research Center of the University Hospital of Quebec - Laval University, Quebec, Canada
| | - Rolf Spirig
- Research, CSL Behring Biologics Research Center, Bern, Switzerland
| | - James C Zimring
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, United States of America
| | - Mark R Looney
- Department of Medicine, UCSF, San Francisco, United States of America
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Cleary SJ, Seo Y, Tian JJ, Kwaan N, Bulkley DP, Bentlage AEH, Vidarsson G, Boilard É, Spirig R, Zimring JC, Looney MR. IgG hexamers initiate acute lung injury. bioRxiv 2024:2024.01.24.577129. [PMID: 38328049 PMCID: PMC10849723 DOI: 10.1101/2024.01.24.577129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Antibodies can initiate lung injury in a variety of disease states such as autoimmunity, transfusion reactions, or after organ transplantation, but the key factors determining in vivo pathogenicity of injury-inducing antibodies are unclear. A previously overlooked step in complement activation by IgG antibodies has been elucidated involving interactions between IgG Fc domains that enable assembly of IgG hexamers, which can optimally activate the complement cascade. Here, we tested the in vivo relevance of IgG hexamers in a complement-dependent alloantibody model of acute lung injury. We used three approaches to block alloantibody hexamerization (antibody carbamylation, the K439E Fc mutation, or treatment with domain B from Staphylococcal protein A), all of which reduced acute lung injury. Conversely, Fc mutations promoting spontaneous hexamerization made a harmful alloantibody into a more potent inducer of acute lung injury and rendered an innocuous alloantibody pathogenic. Treatment with a recombinant Fc hexamer 'decoy' therapeutic protected mice from lung injury, including in a model with transgenic human FCGR2A expression that exacerbated pathology. These results indicate a direct in vivo role of IgG hexamerization in initiating acute lung injury and the potential for therapeutics that inhibit or mimic hexamerization to treat antibody-mediated diseases.
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Affiliation(s)
- Simon J. Cleary
- Department of Medicine, University of California, San Francisco (UCSF), CA, USA
| | - Yurim Seo
- Department of Medicine, University of California, San Francisco (UCSF), CA, USA
| | - Jennifer J. Tian
- Department of Medicine, University of California, San Francisco (UCSF), CA, USA
| | - Nicholas Kwaan
- Department of Medicine, University of California, San Francisco (UCSF), CA, USA
| | - David P. Bulkley
- Department of Biochemistry and Biophysics, University of California, San Francisco (UCSF), CA, USA
| | | | | | - Éric Boilard
- Centre de Recherche du Centre Hospitalier Universitaire de Québec - Université Laval, Québec, QC, Canada
| | - Rolf Spirig
- CSL Behring, Research, CSL Behring Biologics Research Center, Bern, Switzerland
| | - James C. Zimring
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Mark R. Looney
- Department of Medicine, University of California, San Francisco (UCSF), CA, USA
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Sun M, Azumaya CM, Tse E, Bulkley DP, Harrington MB, Gilbert G, Frost A, Southworth D, Verba KA, Cheng Y, Agard DA. Practical considerations for using K3 cameras in CDS mode for high-resolution and high-throughput single particle cryo-EM. J Struct Biol 2021; 213:107745. [PMID: 33984504 DOI: 10.1016/j.jsb.2021.107745] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
Detector technology plays a pivotal role in high-resolution and high-throughput cryo-EM structure determination. Compared with the first-generation, single-electron counting direct detection camera (Gatan K2), the latest K3 camera is faster, larger, and now offers a correlated-double sampling mode (CDS). Importantly this results in a higher DQE and improved throughput compared to its predecessor. In this study, we focused on optimizing camera data collection parameters for daily use within a cryo-EM facility and explored the balance between throughput and resolution. In total, eight data sets of murine heavy-chain apoferritin were collected at different dose rates and magnifications, using 9-hole image shift data collection strategies. The performance of the camera was characterized by the quality of the resultant 3D reconstructions. Our results demonstrated that the Gatan K3 operating in CDS mode outperformed standard (nonCDS) mode in terms of reconstruction resolution in all tested conditions with 8 electrons per pixel per second being the optimal dose rate. At low magnification (64kx) we were able to achieve reconstruction resolutions of 149% of the physical Nyquist limit (1.8 Å with a 1.346 Å physical pixel size). Low magnification allows more particles to be collected per image, aiding analysis of heterogeneous samples requiring large data sets. At moderate magnification (105kx, 0.834 Å physical pixel size) we achieved a resolution of 1.65 Å within 8-h of data collection, a condition optimal for achieving high-resolution on well behaved samples. Our results also show that for an optimal sample like apoferritin, one can achieve better than 2.5 Å resolution with 5 min of data collection. Together, our studies validate the most efficient ways of imaging protein complexes using the K3 direct detector and will greatly benefit the cryo-EM community.
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Affiliation(s)
- Ming Sun
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Caleigh M Azumaya
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Eric Tse
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94158, United States
| | - David P Bulkley
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Matthew B Harrington
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Glenn Gilbert
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Adam Frost
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States; Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, United States
| | - Daniel Southworth
- Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94158, United States
| | - Kliment A Verba
- Quantitative Biosciences Institute (QBI), University of California, San Francisco, CA 94158, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, United States
| | - Yifan Cheng
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States; Howard Hughes Medical Institute, University of California, San Francisco, CA 94158, United States
| | - David A Agard
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States.
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