BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia
Abstract Background The BIN1 locus contains the second-most significant genetic risk factor for late-onset Alzheimer’s disease. BIN1 undergoes alternate splicing to generate tissue- and cell-type-specific BIN1 isoforms, which regulate membrane dynamics in a range of crucial cellular processes. Whils...
| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2022-05-01
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| Series: | Molecular Neurodegeneration |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s13024-022-00535-x |
| _version_ | 1811308186106331136 |
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| author | Ari Sudwarts Supriya Ramesha Tianwen Gao Moorthi Ponnusamy Shuai Wang Mitchell Hansen Alena Kozlova Sara Bitarafan Prateek Kumar David Beaulieu-Abdelahad Xiaolin Zhang Lisa Collier Charles Szekeres Levi B. Wood Jubao Duan Gopal Thinakaran Srikant Rangaraju |
| author_facet | Ari Sudwarts Supriya Ramesha Tianwen Gao Moorthi Ponnusamy Shuai Wang Mitchell Hansen Alena Kozlova Sara Bitarafan Prateek Kumar David Beaulieu-Abdelahad Xiaolin Zhang Lisa Collier Charles Szekeres Levi B. Wood Jubao Duan Gopal Thinakaran Srikant Rangaraju |
| author_sort | Ari Sudwarts |
| collection | DOAJ |
| description | Abstract Background The BIN1 locus contains the second-most significant genetic risk factor for late-onset Alzheimer’s disease. BIN1 undergoes alternate splicing to generate tissue- and cell-type-specific BIN1 isoforms, which regulate membrane dynamics in a range of crucial cellular processes. Whilst the expression of BIN1 in the brain has been characterized in neurons and oligodendrocytes in detail, information regarding microglial BIN1 expression is mainly limited to large-scale transcriptomic and proteomic data. Notably, BIN1 protein expression and its functional roles in microglia, a cell type most relevant to Alzheimer’s disease, have not been examined in depth. Methods Microglial BIN1 expression was analyzed by immunostaining mouse and human brain, as well as by immunoblot and RT-PCR assays of isolated microglia or human iPSC-derived microglial cells. Bin1 expression was ablated by siRNA knockdown in primary microglial cultures in vitro and Cre-lox mediated conditional deletion in adult mouse brain microglia in vivo. Regulation of neuroinflammatory microglial signatures by BIN1 in vitro and in vivo was characterized using NanoString gene panels and flow cytometry methods. The transcriptome data was explored by in silico pathway analysis and validated by complementary molecular approaches. Results Here, we characterized microglial BIN1 expression in vitro and in vivo and ascertained microglia expressed BIN1 isoforms. By silencing Bin1 expression in primary microglial cultures, we demonstrate that BIN1 regulates the activation of proinflammatory and disease-associated responses in microglia as measured by gene expression and cytokine production. Our transcriptomic profiling revealed key homeostatic and lipopolysaccharide (LPS)-induced inflammatory response pathways, as well as transcription factors PU.1 and IRF1 that are regulated by BIN1. Microglia-specific Bin1 conditional knockout in vivo revealed novel roles of BIN1 in regulating the expression of disease-associated genes while counteracting CX3CR1 signaling. The consensus from in vitro and in vivo findings showed that loss of Bin1 impaired the ability of microglia to mount type 1 interferon responses to proinflammatory challenge, particularly the upregulation of a critical type 1 immune response gene, Ifitm3. Conclusions Our convergent findings provide novel insights into microglial BIN1 function and demonstrate an essential role of microglial BIN1 in regulating brain inflammatory response and microglial phenotypic changes. Moreover, for the first time, our study shows a regulatory relationship between Bin1 and Ifitm3, two Alzheimer’s disease-related genes in microglia. The requirement for BIN1 to regulate Ifitm3 upregulation during inflammation has important implications for inflammatory responses during the pathogenesis and progression of many neurodegenerative diseases. Graphical Abstract |
| first_indexed | 2024-04-13T09:18:51Z |
| format | Article |
| id | doaj.art-5b885f3d291245d3b19ec792e0b820ed |
| institution | Directory Open Access Journal |
| issn | 1750-1326 |
| language | English |
| last_indexed | 2024-04-13T09:18:51Z |
| publishDate | 2022-05-01 |
| publisher | BMC |
| record_format | Article |
| series | Molecular Neurodegeneration |
| spelling | doaj.art-5b885f3d291245d3b19ec792e0b820ed2022-12-22T02:52:40ZengBMCMolecular Neurodegeneration1750-13262022-05-0117112710.1186/s13024-022-00535-xBIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microgliaAri Sudwarts0Supriya Ramesha1Tianwen Gao2Moorthi Ponnusamy3Shuai Wang4Mitchell Hansen5Alena Kozlova6Sara Bitarafan7Prateek Kumar8David Beaulieu-Abdelahad9Xiaolin Zhang10Lisa Collier11Charles Szekeres12Levi B. Wood13Jubao Duan14Gopal Thinakaran15Srikant Rangaraju16Byrd Alzheimer’s Center and Research Institute, University of South FloridaDepartment of Neurology, Emory UniversityDepartment of Neurology, Emory UniversityByrd Alzheimer’s Center and Research Institute, University of South FloridaByrd Alzheimer’s Center and Research Institute, University of South FloridaByrd Alzheimer’s Center and Research Institute, University of South FloridaCenter for Psychiatric Genetics, North Shore University Health SystemParker H. Petit Institute for Bioengineering and Bioscience, Wallace H. Coulter Department of Biomedical Engineering, and Georgia W. Woodruff School of Mechanical Engineering, Georgia Institute of TechnologyDepartment of Neurology, Emory UniversityByrd Alzheimer’s Center and Research Institute, University of South FloridaByrd Alzheimer’s Center and Research Institute, University of South FloridaByrd Alzheimer’s Center and Research Institute, University of South FloridaDepartment of Molecular Medicine, Morsani College of Medicine, University of South FloridaParker H. Petit Institute for Bioengineering and Bioscience, Wallace H. Coulter Department of Biomedical Engineering, and Georgia W. Woodruff School of Mechanical Engineering, Georgia Institute of TechnologyCenter for Psychiatric Genetics, North Shore University Health SystemByrd Alzheimer’s Center and Research Institute, University of South FloridaDepartment of Neurology, Emory UniversityAbstract Background The BIN1 locus contains the second-most significant genetic risk factor for late-onset Alzheimer’s disease. BIN1 undergoes alternate splicing to generate tissue- and cell-type-specific BIN1 isoforms, which regulate membrane dynamics in a range of crucial cellular processes. Whilst the expression of BIN1 in the brain has been characterized in neurons and oligodendrocytes in detail, information regarding microglial BIN1 expression is mainly limited to large-scale transcriptomic and proteomic data. Notably, BIN1 protein expression and its functional roles in microglia, a cell type most relevant to Alzheimer’s disease, have not been examined in depth. Methods Microglial BIN1 expression was analyzed by immunostaining mouse and human brain, as well as by immunoblot and RT-PCR assays of isolated microglia or human iPSC-derived microglial cells. Bin1 expression was ablated by siRNA knockdown in primary microglial cultures in vitro and Cre-lox mediated conditional deletion in adult mouse brain microglia in vivo. Regulation of neuroinflammatory microglial signatures by BIN1 in vitro and in vivo was characterized using NanoString gene panels and flow cytometry methods. The transcriptome data was explored by in silico pathway analysis and validated by complementary molecular approaches. Results Here, we characterized microglial BIN1 expression in vitro and in vivo and ascertained microglia expressed BIN1 isoforms. By silencing Bin1 expression in primary microglial cultures, we demonstrate that BIN1 regulates the activation of proinflammatory and disease-associated responses in microglia as measured by gene expression and cytokine production. Our transcriptomic profiling revealed key homeostatic and lipopolysaccharide (LPS)-induced inflammatory response pathways, as well as transcription factors PU.1 and IRF1 that are regulated by BIN1. Microglia-specific Bin1 conditional knockout in vivo revealed novel roles of BIN1 in regulating the expression of disease-associated genes while counteracting CX3CR1 signaling. The consensus from in vitro and in vivo findings showed that loss of Bin1 impaired the ability of microglia to mount type 1 interferon responses to proinflammatory challenge, particularly the upregulation of a critical type 1 immune response gene, Ifitm3. Conclusions Our convergent findings provide novel insights into microglial BIN1 function and demonstrate an essential role of microglial BIN1 in regulating brain inflammatory response and microglial phenotypic changes. Moreover, for the first time, our study shows a regulatory relationship between Bin1 and Ifitm3, two Alzheimer’s disease-related genes in microglia. The requirement for BIN1 to regulate Ifitm3 upregulation during inflammation has important implications for inflammatory responses during the pathogenesis and progression of many neurodegenerative diseases. Graphical Abstracthttps://doi.org/10.1186/s13024-022-00535-xBIN1Alzheimer’s diseaseNeuroinflammationMicrogliaInnate immunityGWAS risk factor |
| spellingShingle | Ari Sudwarts Supriya Ramesha Tianwen Gao Moorthi Ponnusamy Shuai Wang Mitchell Hansen Alena Kozlova Sara Bitarafan Prateek Kumar David Beaulieu-Abdelahad Xiaolin Zhang Lisa Collier Charles Szekeres Levi B. Wood Jubao Duan Gopal Thinakaran Srikant Rangaraju BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia Molecular Neurodegeneration BIN1 Alzheimer’s disease Neuroinflammation Microglia Innate immunity GWAS risk factor |
| title | BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia |
| title_full | BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia |
| title_fullStr | BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia |
| title_full_unstemmed | BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia |
| title_short | BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia |
| title_sort | bin1 is a key regulator of proinflammatory and neurodegeneration related activation in microglia |
| topic | BIN1 Alzheimer’s disease Neuroinflammation Microglia Innate immunity GWAS risk factor |
| url | https://doi.org/10.1186/s13024-022-00535-x |
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