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Anwar MM, Pérez-Martínez L, Pedraza-Alva G. Exploring the Significance of Microglial Phenotypes and Morphological Diversity in Neuroinflammation and Neurodegenerative Diseases: From Mechanisms to Potential Therapeutic Targets. Immunol Invest 2024; 53:891-946. [PMID: 38836373 DOI: 10.1080/08820139.2024.2358446] [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: 06/06/2024]
Abstract
Studying various microglial phenotypes and their functions in neurodegenerative diseases is crucial due to the intricate nature of their phenomics and their vital immunological role. Microglia undergo substantial phenomic changes, encompassing morphological, transcriptional, and functional aspects, resulting in distinct cell types with diverse structures, functions, properties, and implications. The traditional classification of microglia as ramified, M1 (proinflammatory), or M2 (anti-inflammatory) phenotypes is overly simplistic, failing to capture the wide range of recently identified microglial phenotypes in various brain regions affected by neurodegenerative diseases. Altered and activated microglial phenotypes deviating from the typical ramified structure are significant features of many neurodegenerative conditions. Understanding the precise role of each microglial phenotype is intricate and sometimes contradictory. This review specifically focuses on elucidating recent modifications in microglial phenotypes within neurodegenerative diseases. Recognizing the heterogeneity of microglial phenotypes in diseased states can unveil novel therapeutic strategies for targeting microglia in neurodegenerative diseases. Moreover, the exploration of the use of healthy isolated microglia to mitigate disease progression has provided an innovative perspective. In conclusion, this review discusses the dynamic landscape of mysterious microglial phenotypes, emphasizing the need for a nuanced understanding to pave the way for innovative therapeutic strategies for neurodegenerative diseases.
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Affiliation(s)
- Mai M Anwar
- Department of Biochemistry, National Organization for Drug Control and Research (NODCAR)/Egyptian Drug Authority (EDA), Cairo, Egypt
| | - Leonor Pérez-Martínez
- Neuroimmunobiology Laboratory, Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Cuernavaca, Morelos, Mexico
| | - Gustavo Pedraza-Alva
- Neuroimmunobiology Laboratory, Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Cuernavaca, Morelos, Mexico
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2
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Tesla R, Guhl C, Werthmann GC, Dixon D, Cenik B, Addepalli Y, Liang J, Fass DM, Rosenthal Z, Haggarty SJ, Williams NS, Posner BA, Ready JM, Herz J. Benzoxazole-derivatives enhance progranulin expression and reverse the aberrant lysosomal proteome caused by GRN haploinsufficiency. Nat Commun 2024; 15:6125. [PMID: 39033178 PMCID: PMC11271458 DOI: 10.1038/s41467-024-50076-8] [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: 05/29/2023] [Accepted: 07/01/2024] [Indexed: 07/23/2024] Open
Abstract
Heterozygous loss-of-function mutations in the GRN gene are a major cause of hereditary frontotemporal dementia. The mechanisms linking frontotemporal dementia pathogenesis to progranulin deficiency are not well understood, and there is currently no treatment. Our strategy to prevent the onset and progression of frontotemporal dementia in patients with GRN mutations is to utilize small molecule positive regulators of GRN expression to boost progranulin levels from the remaining functional GRN allele, thus restoring progranulin levels back to normal within the brain. This work describes a series of blood-brain-barrier-penetrant small molecules which significantly increase progranulin protein levels in human cellular models, correct progranulin protein deficiency in Grn+/- mouse brains, and reverse lysosomal proteome aberrations, a phenotypic hallmark of frontotemporal dementia, more efficiently than the previously described small molecule suberoylanilide hydroxamic acid. These molecules will allow further elucidation of the cellular functions of progranulin and its role in frontotemporal dementia and will also serve as lead structures for further drug development.
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Affiliation(s)
- Rachel Tesla
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Center for Translational Neurodegeneration Research, Dallas, TX, USA
| | - Charlotte Guhl
- Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Gordon C Werthmann
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Center for Translational Neurodegeneration Research, Dallas, TX, USA
| | - Danielle Dixon
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Center for Translational Neurodegeneration Research, Dallas, TX, USA
| | - Basar Cenik
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Center for Translational Neurodegeneration Research, Dallas, TX, USA
| | - Yesu Addepalli
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jue Liang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Daniel M Fass
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Departments of Neurology and Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Zachary Rosenthal
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Stephen J Haggarty
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Departments of Neurology and Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Noelle S Williams
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bruce A Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joseph M Ready
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joachim Herz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Center for Translational Neurodegeneration Research, Dallas, TX, USA.
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Zhao M, Wang M, Chen X, Gao Y, Chen Q, Wang L, Bao Q, Sun D, Du W, Xu Y, Xie L, Jiang X, Zhang L, Peng L, Zhang B, Yao Y. Targeting progranulin alleviated silica particles-induced pulmonary inflammation and fibrosis via decreasing Il-6 and Tgf-β1/Smad. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133199. [PMID: 38103296 DOI: 10.1016/j.jhazmat.2023.133199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/12/2023] [Accepted: 12/05/2023] [Indexed: 12/19/2023]
Abstract
Long term exposure to silica particles leads to various diseases, among which silicosis is of great concern. Silicosis is an interstitial lung disease caused by inhalation of silica particles in production environments. However, the mechanisms underlying silicosis remains unclear. Our previous studies revealed that progranulin (Pgrn) promoted the expression of pro-inflammatory factors in alveolar macrophages treated with silica particles and the secretion of extracellular matrix of pulmonary fibroblasts. Nevertheless, the role of Pgrn in silica particles-induced silicosis in vivo was unknown. This study found that silica particles increased Pgrn expression in silicosis patients. Pgrn deficiency reduced lung inflammation and fibrosis in silica particles-induced silicosis mouse models. Subsequently, based on transcriptional sequencing and interleukin (Il) -6 knockout mouse models, results demonstrated that Pgrn deficiency might decrease silicosis inflammation by reducing the production of Il-6, thereby modulating pulmonary fibrosis in the early stage of silicosis mouse models. Furthermore, another mechanism through which Pgrn deficiency reduced fibrosis in silicosis mouse models was the regulation of the transforming growth factor (Tgf) -β1/Smad signaling pathway. Conclusively, Pgrn contributed to silicosis inflammation and fibrosis induced by silica particles, indicating that Pgrn could be a promising therapeutic target.
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Affiliation(s)
- Manyu Zhao
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Mengzhu Wang
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Xuxi Chen
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Ying Gao
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Qing Chen
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Liqun Wang
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Qixue Bao
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Donglei Sun
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Wen Du
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Yunyi Xu
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Linshen Xie
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Xia Jiang
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Ling Zhang
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Lijun Peng
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
| | - Ben Zhang
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; Departments of Cardiology, Neurology, and Oncology, Hainan General Hospital and Hainan Affiliated Hospital, Hainan Medical University, Haikou 570311, China.
| | - Yuqin Yao
- Molecular Toxicology Laboratory of Sichuan Provincial Education office, Institute of Systems Epidemiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China; West China Occupational Pneumoconiosis Cohort Study (WCOPCS) working group, Research Center For Prevention and Therapy of Occupational Disease, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China.
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4
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Sung W, Noh MY, Nahm M, Kim YS, Ki CS, Kim YE, Kim HJ, Kim SH. Progranulin haploinsufficiency mediates cytoplasmic TDP-43 aggregation with lysosomal abnormalities in human microglia. J Neuroinflammation 2024; 21:47. [PMID: 38347588 PMCID: PMC10863104 DOI: 10.1186/s12974-024-03039-1] [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: 12/21/2023] [Accepted: 02/07/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND Progranulin (PGRN) haploinsufficiency due to progranulin gene (GRN) variants can cause frontotemporal dementia (FTD) with aberrant TAR DNA-binding protein 43 (TDP-43) accumulation. Despite microglial burden with TDP-43-related pathophysiology, direct microglial TDP-43 pathology has not been clarified yet, only emphasized in neuronal pathology. Thus, the objective of this study was to investigate TDP-43 pathology in microglia of patients with PGRN haploinsufficiency. METHODS To design a human microglial cell model with PGRN haploinsufficiency, monocyte-derived microglia (iMGs) were generated from FTD-GRN patients carrying pathogenic or likely pathogenic variants (p.M1? and p.W147*) and three healthy controls. RESULTS iMGs from FTD-GRN patients with PGRN deficiency exhibited severe neuroinflammation phenotype and failure to maintain their homeostatic molecular signatures, along with impaired phagocytosis. In FTD-GRN patients-derived iMGs, significant cytoplasmic TDP-43 aggregation and accumulation of lipid droplets with profound lysosomal abnormalities were observed. These pathomechanisms were mediated by complement C1q activation and upregulation of pro-inflammatory cytokines. CONCLUSIONS Our study provides considerable cellular and molecular evidence that loss-of-function variants of GRN in human microglia can cause microglial dysfunction with abnormal TDP-43 aggregation induced by inflammatory milieu as well as the impaired lysosome. Elucidating the role of microglial TDP-43 pathology in intensifying neuroinflammation in individuals with FTD due to PGRN deficiency and examining consequential effects on microglial dysfunction might yield novel insights into the mechanisms underlying FTD and neurodegenerative disorders.
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Affiliation(s)
- Wonjae Sung
- Department of Neurology, College of Medicine, Hanyang University, 222, Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea
| | - Min-Young Noh
- Department of Neurology, College of Medicine, Hanyang University, 222, Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea
| | - Minyeop Nahm
- Dementia Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Yong Sung Kim
- Department of Neurology, College of Medicine, Hanyang University, 222, Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea
| | | | - Young-Eun Kim
- Department of Laboratory Medicine, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - Hee-Jin Kim
- Department of Neurology, College of Medicine, Hanyang University, 222, Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea
| | - Seung Hyun Kim
- Department of Neurology, College of Medicine, Hanyang University, 222, Wangsimni-Ro, Seongdong-Gu, Seoul, 04763, Republic of Korea.
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5
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Gao C, Jiang J, Tan Y, Chen S. Microglia in neurodegenerative diseases: mechanism and potential therapeutic targets. Signal Transduct Target Ther 2023; 8:359. [PMID: 37735487 PMCID: PMC10514343 DOI: 10.1038/s41392-023-01588-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/11/2023] [Accepted: 08/03/2023] [Indexed: 09/23/2023] Open
Abstract
Microglia activation is observed in various neurodegenerative diseases. Recent advances in single-cell technologies have revealed that these reactive microglia were with high spatial and temporal heterogeneity. Some identified microglia in specific states correlate with pathological hallmarks and are associated with specific functions. Microglia both exert protective function by phagocytosing and clearing pathological protein aggregates and play detrimental roles due to excessive uptake of protein aggregates, which would lead to microglial phagocytic ability impairment, neuroinflammation, and eventually neurodegeneration. In addition, peripheral immune cells infiltration shapes microglia into a pro-inflammatory phenotype and accelerates disease progression. Microglia also act as a mobile vehicle to propagate protein aggregates. Extracellular vesicles released from microglia and autophagy impairment in microglia all contribute to pathological progression and neurodegeneration. Thus, enhancing microglial phagocytosis, reducing microglial-mediated neuroinflammation, inhibiting microglial exosome synthesis and secretion, and promoting microglial conversion into a protective phenotype are considered to be promising strategies for the therapy of neurodegenerative diseases. Here we comprehensively review the biology of microglia and the roles of microglia in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, multiple system atrophy, amyotrophic lateral sclerosis, frontotemporal dementia, progressive supranuclear palsy, corticobasal degeneration, dementia with Lewy bodies and Huntington's disease. We also summarize the possible microglia-targeted interventions and treatments against neurodegenerative diseases with preclinical and clinical evidence in cell experiments, animal studies, and clinical trials.
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Affiliation(s)
- Chao Gao
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Jingwen Jiang
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Yuyan Tan
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China.
| | - Shengdi Chen
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China.
- Lab for Translational Research of Neurodegenerative Diseases, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), Shanghai Tech University, 201210, Shanghai, China.
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6
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Life B, Petkau TL, Cruz GNF, Navarro-Delgado EI, Shen N, Korthauer K, Leavitt BR. FTD-associated behavioural and transcriptomic abnormalities in 'humanized' progranulin-deficient mice: A novel model for progranulin-associated FTD. Neurobiol Dis 2023; 182:106138. [PMID: 37105261 DOI: 10.1016/j.nbd.2023.106138] [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: 03/15/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023] Open
Abstract
Frontotemporal dementia (FTD) is an early onset dementia characterized by neuropathology and behavioural changes. A common genetic cause of FTD is haploinsufficiency of the gene progranulin (GRN). Mouse models of progranulin deficiency have provided insight into progranulin neurobiology, but the description of phenotypes with preclinical relevance has been limited in the currently available heterozygous progranulin-null mice. The identification of robust and reproducible FTD-associated behavioural, neuropathological, and biochemical phenotypes in progranulin deficient mice is a critical step in the preclinical development of therapies for FTD. In this work, we report the generation of a novel, 'humanized' mouse model of progranulin deficiency that expresses a single, targeted copy of human GRN in the absence of mouse progranulin. We also report the in-depth, longitudinal characterization of humanized progranulin-deficient mice and heterozygous progranulin-null mice over 18 months. Our analysis yielded several novel progranulin-dependent physiological and behavioural phenotypes, including increased marble burying, open field hyperactivity, and thalamic microgliosis in both models. RNAseq analysis of cortical tissue revealed an overlapping profile of transcriptomic dysfunction. Further transcriptomic analysis offers new insights into progranulin neurobiology. In sum, we have identified several consistent phenotypes in two independent mouse models of progranulin deficiency that are expected to be useful endpoints in the development of therapies for progranulin-deficient FTD. Furthermore, the presence of the human progranulin gene in the humanized progranulin-deficient mice will expedite the development of clinically translatable gene therapy strategies.
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Affiliation(s)
- Benjamin Life
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 0B3, Canada; BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Terri L Petkau
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 0B3, Canada; BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Giuliano N F Cruz
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Erick I Navarro-Delgado
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ning Shen
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Keegan Korthauer
- BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Department of Statistics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 0B3, Canada; BC Children's Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada; Division of Neurology, Department of Medicine, University of British Columbia Hospital, Vancouver, BC V6T 2B5, Canada; Center for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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7
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Simon MJ, Logan T, DeVos SL, Di Paolo G. Lysosomal functions of progranulin and implications for treatment of frontotemporal dementia. Trends Cell Biol 2023; 33:324-339. [PMID: 36244875 DOI: 10.1016/j.tcb.2022.09.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 12/12/2022]
Abstract
Loss-of-function heterozygous mutations in GRN, the gene encoding progranulin (PGRN), were identified in patients with frontotemporal lobar degeneration (FTLD) almost two decades ago and are generally linked to reduced PGRN protein expression levels. Although initial characterization of PGRN function primarily focused on its role in extracellular signaling as a secreted protein, more recent studies revealed critical roles of PGRN in regulating lysosome function, including proteolysis and lipid degradation, consistent with its lysosomal localization. Emerging from these studies is the notion that PGRN regulates glucocerebrosidase activity via direct chaperone activities and via interaction with prosaposin (i.e., a key regulator of lysosomal sphingolipid-metabolizing enzymes), as well as with the anionic phospholipid bis(monoacylglycero)phosphate. This emerging lysosomal biology of PGRN identified novel and promising opportunities in therapeutic discovery as well as biomarker development.
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Affiliation(s)
| | - Todd Logan
- Denali Therapeutics, South San Francisco, CA, USA
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8
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Henn RE, Guo K, Elzinga SE, Noureldein MH, Mendelson FE, Hayes JM, Rigan DM, Savelieff MG, Hur J, Feldman EL. Single-cell RNA sequencing identifies hippocampal microglial dysregulation in diet-induced obesity. iScience 2023; 26:106164. [PMID: 36915697 PMCID: PMC10006681 DOI: 10.1016/j.isci.2023.106164] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 12/23/2022] [Accepted: 02/02/2023] [Indexed: 02/10/2023] Open
Abstract
Obesity is a growing global concern in adults and youth with a parallel rise in associated complications, including cognitive impairment. Obesity induces brain inflammation and activates microglia, which contribute to cognitive impairment by aberrantly phagocytosing synaptic spines. Local and systemic signals, such as inflammatory cytokines and metabolites likely participate in obesity-induced microglial activation. However, the precise mechanisms mediating microglial activation during obesity remain incompletely understood. Herein, we leveraged our mouse model of high-fat diet (HFD)-induced obesity, which mirrors human obesity, and develops hippocampal-dependent cognitive impairment. We assessed hippocampal microglial activation by morphological and single-cell transcriptomic analysis to evaluate this heterogeneous, functionally diverse, and dynamic class of cells over time after 1 and 3 months of HFD. HFD altered cell-to-cell communication, particularly immune modulation and cellular adhesion signaling, and induced a differential gene expression signature of protein processing in the endoplasmic reticulum in a time-dependent manner.
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Affiliation(s)
- Rosemary E. Henn
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Kai Guo
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Sarah E. Elzinga
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Mohamed H. Noureldein
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Faye E. Mendelson
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - John M. Hayes
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Diana M. Rigan
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Masha G. Savelieff
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND, USA
| | - Eva L. Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- NeuroNetwork for Emerging Therapies, University of Michigan, Ann Arbor, MI, USA
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9
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Vijaya AK, Iešmantaitė M, Mela V, Baltriukienė D, Burokas A. Microglia isolation from aging mice for cell culture: A beginner's guide. Front Cell Neurosci 2023; 17:1082180. [PMID: 36744004 PMCID: PMC9893793 DOI: 10.3389/fncel.2023.1082180] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/03/2023] [Indexed: 01/20/2023] Open
Abstract
Microglia, the innate immune cell of the central nervous system, play significant roles in brain development, maintenance, homeostasis, and neuroinflammation. Although numerous methods have been developed to isolate microglia from embryonic or postnatal mouse brains, still major difficulties exist in isolating microglia from adult mice, often resulting in low yield and risk of cellular activation. Therefore, there is a need for a more efficient method to isolate pure and high-yield microglia from adult mice to study various neurodegenerative diseases. The aim of this study was to develop a fully functional protocol for the isolation of microglia by comparing different protocols. We investigated the efficacy of three protocols in terms of cell yield, purity, cellular activation, cellular aging, and migration properties and proposed the modified protocol (PROTOCOL 1), which provides an optimal yield of functional microglial cells with a minimum of material and equipment and allows young researchers with little experience to isolate microglia and helps them to delve deeper into the world of neuroscience.
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Affiliation(s)
- Akshay Kumar Vijaya
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Monika Iešmantaitė
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Virginia Mela
- Department of Medicine and Dermatology, Faculty of Medicine, University of Malaga, Málaga, Spain
| | - Daiva Baltriukienė
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania,*Correspondence: Daiva Baltriukienė,
| | - Aurelijus Burokas
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania,Aurelijus Burokas,
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Plasma Small Extracellular Vesicle Cathepsin D Dysregulation in GRN/C9orf72 and Sporadic Frontotemporal Lobar Degeneration. Int J Mol Sci 2022; 23:ijms231810693. [PMID: 36142612 PMCID: PMC9504770 DOI: 10.3390/ijms231810693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/08/2022] [Accepted: 09/11/2022] [Indexed: 11/22/2022] Open
Abstract
Emerging data suggest the roles of endo-lysosomal dysfunctions in frontotemporal lobar degeneration (FTLD) and in other dementias. Cathepsin D is one of the major lysosomal proteases, mediating the degradation of unfolded protein aggregates. In this retrospective study, we investigated cathepsin D levels in human plasma and in the plasma small extracellular vesicles (sEVs) of 161 subjects (40 sporadic FTLD, 33 intermediate/pathological C9orf72 expansion carriers, 45 heterozygous/homozygous GRN mutation carriers, and 43 controls). Cathepsin D was quantified by ELISA, and nanoparticle tracking analysis data (sEV concentration for the cathepsin D level normalization) were extracted from our previously published dataset or were newly generated. First, we revealed a positive correlation of the cathepsin D levels with the age of the patients and controls. Even if no significant differences were found in the cathepsin D plasma levels, we observed a progressive reduction in plasma cathepsin D moving from the intermediate to C9orf72 pathological expansion carriers. Observing the sEVs nano-compartment, we observed increased cathepsin D sEV cargo (ng/sEV) levels in genetic/sporadic FTLD. The diagnostic performance of this biomarker was fairly high (AUC = 0.85). Moreover, sEV and plasma cathepsin D levels were positively correlated with age at onset. In conclusion, our study further emphasizes the common occurrence of endo-lysosomal dysregulation in GRN/C9orf72 and sporadic FTLD.
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11
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Aktories P, Petry P, Kierdorf K. Microglia in a Dish—Which Techniques Are on the Menu for Functional Studies? Front Cell Neurosci 2022; 16:908315. [PMID: 35722614 PMCID: PMC9204042 DOI: 10.3389/fncel.2022.908315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/11/2022] [Indexed: 12/12/2022] Open
Abstract
Microglia build the first line of defense in the central nervous system (CNS) and play central roles during development and homeostasis. Indeed, they serve a plethora of diverse functions in the CNS of which many are not yet fully described and more are still to be discovered. Research of the last decades unraveled an implication of microglia in nearly every neurodegenerative and neuroinflammatory disease, making it even more challenging to elucidate molecular mechanisms behind microglial functions and to modulate aberrant microglial behavior. To understand microglial functions and the underlying signaling machinery, many attempts were made to employ functional in vitro studies of microglia. However, the range of available cell culture models is wide and they come with different advantages and disadvantages for functional assays. Here we aim to provide a condensed summary of common microglia in vitro systems and discuss their potentials and shortcomings for functional studies in vitro.
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Affiliation(s)
- Philipp Aktories
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Philippe Petry
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- *Correspondence: Katrin Kierdorf
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12
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Amin S, Carling G, Gan L. New insights and therapeutic opportunities for progranulin-deficient frontotemporal dementia. Curr Opin Neurobiol 2022; 72:131-139. [PMID: 34826653 DOI: 10.1016/j.conb.2021.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/19/2021] [Indexed: 01/02/2023]
Abstract
Frontotemporal dementia (FTD) is the second most common form of dementia. It affects the frontal and temporal lobes of the brain and has a highly heterogeneous clinical representation with patients presenting with a wide range of behavioral, language, and executive dysfunctions. Etiology of FTD is complex and consists of both familial and sporadic cases. Heterozygous mutations in the GRN gene, resulting in GRN haploinsufficiency, cause progranulin (PGRN)-deficient FTD characterized with cytoplasmic mislocalization of TAR DNA-binding protein 43 kDa (TDP-43) aggregates. GRN codes for PGRN, a secreted protein that is also localized in the endolysosomes and plays a critical role in regulating lysosomal homeostasis. How PGRN deficiency modulates immunity and causes TDP-43 pathology and FTD-related neurodegeneration remains an active area of intense investigation. In the current review, we discuss some of the significant progress made in the past two years that links PGRN deficiency with microglial-associated neuroinflammation, TDP-43 pathology, and lysosomal dysfunction. We also review the opportunities and challenges toward developing therapies and biomarkers to treat PGRN-deficient FTD.
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Affiliation(s)
- Sadaf Amin
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Gillian Carling
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA; Neuroscience Graduate Program, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Li Gan
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA.
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13
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Wu Y, Shao W, Todd TW, Tong J, Yue M, Koga S, Castanedes-Casey M, Librero AL, Lee CW, Mackenzie IR, Dickson DW, Zhang YJ, Petrucelli L, Prudencio M. Microglial lysosome dysfunction contributes to white matter pathology and TDP-43 proteinopathy in GRN-associated FTD. Cell Rep 2021; 36:109581. [PMID: 34433069 PMCID: PMC8491969 DOI: 10.1016/j.celrep.2021.109581] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/07/2021] [Accepted: 07/29/2021] [Indexed: 11/04/2022] Open
Abstract
Loss-of-function mutations in the progranulin gene (GRN), which encodes progranulin (PGRN), are a major cause of frontotemporal dementia (FTD). GRN-associated FTD is characterized by TDP-43 inclusions and neuroinflammation, but how PGRN loss causes disease remains elusive. We show that Grn knockout (KO) mice have increased microgliosis in white matter and an accumulation of myelin debris in microglial lysosomes in the same regions. Accumulation of myelin debris is also observed in white matter of patients with GRN-associated FTD. In addition, our findings also suggest that PGRN insufficiency in microglia leads to impaired lysosomal-mediated clearance of myelin debris. Finally, Grn KO mice that are deficient in cathepsin D (Ctsd), a key lysosomal enzyme, have augmented myelin debris and increased neuronal TDP-43 pathology. Together, our data strongly imply that PGRN loss affects microglial activation and lysosomal function, resulting in the accumulation of myelin debris and contributing to TDP-43 pathology. Wu et al. show increased microgliosis in white matter of Grn knockout mice. Microglial lysosomes accumulate myelin debris in both Grn knockout mice and patients with GRN-associated FTD, and reducing cathespin D levels exacerbates both myelin debris accumulation and pTdp-43 aggregation. Thus, lysosomal dysfunction affects these pathologies in GRN-related FTD.
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Affiliation(s)
- Yanwei Wu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wei Shao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Tiffany W Todd
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Jimei Tong
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Mei Yue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Shunsuke Koga
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Ariston L Librero
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Chris W Lee
- Atlantic Health System, Morristown, NJ 07960, USA; Biomedical Research Institute of New Jersey, Cedar Knolls, NJ 07927, USA
| | - Ian R Mackenzie
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Yong-Jie Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA.
| | - Mercedes Prudencio
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA.
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Natarajan K, Eisfeldt J, Hammond M, Laffita-Mesa JM, Patra K, Khoshnood B, Öijerstedt L, Graff C. Single-cell multimodal analysis in a case with reduced penetrance of Progranulin-Frontotemporal Dementia. Acta Neuropathol Commun 2021; 9:132. [PMID: 34344473 PMCID: PMC8336016 DOI: 10.1186/s40478-021-01234-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/23/2021] [Indexed: 11/10/2022] Open
Abstract
We identified an autosomal dominant progranulin mutation carrier without symptoms of dementia in her lifetime (Reduced Penetrance Mutation Carrier, RedPenMC). This resistance to develop expected pathology presents a unique opportunity to interrogate neurodegenerative mechanisms. We performed multimodal single-nuclei analyses of post-mortem frontal cortex from RedPenMC, including transcriptomics and global levels of chromatin marks. RedPenMC had an increased ratio of GRN-expressing microglia, higher levels of activating histone mark H3k4me3 in microglia and lower levels of the repressive chromatin marks H3k9me1 and H3k9me3 in the frontal cortex than her affected mutation carrier son and evidence of higher protein levels of progranulin in both plasma and brain homogenates. Although the study is limited to one case, the results support that restoring brain progranulin levels may be sufficient to escape neurodegeneration and FTD. In addition to previously identified modifier genes, it is possible that epigenetic marks may contribute to the increased progranulin expression in cases of reduced penetrance. These findings may stimulate similar follow-up studies and new therapeutic approaches.
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15
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Steuten K, Kim H, Widen JC, Babin BM, Onguka O, Lovell S, Bolgi O, Cerikan B, Neufeldt CJ, Cortese M, Muir RK, Bennett JM, Geiss-Friedlander R, Peters C, Bartenschlager R, Bogyo M. Challenges for Targeting SARS-CoV-2 Proteases as a Therapeutic Strategy for COVID-19. ACS Infect Dis 2021; 7:1457-1468. [PMID: 33570381 PMCID: PMC7901237 DOI: 10.1021/acsinfecdis.0c00815] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Indexed: 12/31/2022]
Abstract
Two proteases produced by the SARS-CoV-2 virus, the main protease and papain-like protease, are essential for viral replication and have become the focus of drug development programs for treatment of COVID-19. We screened a highly focused library of compounds containing covalent warheads designed to target cysteine proteases to identify new lead scaffolds for both Mpro and PLpro proteases. These efforts identified a small number of hits for the Mpro protease and no viable hits for the PLpro protease. Of the Mpro hits identified as inhibitors of the purified recombinant protease, only two compounds inhibited viral infectivity in cellular infection assays. However, we observed a substantial drop in antiviral potency upon expression of TMPRSS2, a transmembrane serine protease that acts in an alternative viral entry pathway to the lysosomal cathepsins. This loss of potency is explained by the fact that our lead Mpro inhibitors are also potent inhibitors of host cell cysteine cathepsins. To determine if this is a general property of Mpro inhibitors, we evaluated several recently reported compounds and found that they are also effective inhibitors of purified human cathepsins L and B and showed similar loss in activity in cells expressing TMPRSS2. Our results highlight the challenges of targeting Mpro and PLpro proteases and demonstrate the need to carefully assess selectivity of SARS-CoV-2 protease inhibitors to prevent clinical advancement of compounds that function through inhibition of a redundant viral entry pathway.
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Affiliation(s)
- Kas Steuten
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Heeyoung Kim
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany
- German Center for Infection Research (DZIF), Heidelberg partner site, Heidelberg, Germany
| | - John C. Widen
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Brett M. Babin
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Ouma Onguka
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Scott Lovell
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Oguz Bolgi
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
| | - Berati Cerikan
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Christopher J. Neufeldt
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Mirko Cortese
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Ryan K. Muir
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - John M. Bennett
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
| | - Ruth Geiss-Friedlander
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
| | - Christoph Peters
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany
- Division Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, German
- German Center for Infection Research (DZIF), Heidelberg partner site, Heidelberg, Germany
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, United States
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