1
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Xu X, Niu M, Lamberty BG, Emanuel K, Ramachandran S, Trease AJ, Tabassum M, Lifson JD, Fox HS. Microglia and macrophages alterations in the CNS during acute SIV infection: A single-cell analysis in rhesus macaques. PLoS Pathog 2024; 20:e1012168. [PMID: 39283947 PMCID: PMC11426456 DOI: 10.1371/journal.ppat.1012168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 09/26/2024] [Accepted: 08/26/2024] [Indexed: 09/25/2024] Open
Abstract
Human Immunodeficiency Virus (HIV) is widely acknowledged for its profound impact on the immune system. Although HIV primarily affects peripheral CD4 T cells, its influence on the central nervous system (CNS) cannot be overlooked. Within the brain, microglia and CNS-associated macrophages (CAMs) serve as the primary targets for HIV and the simian immunodeficiency virus (SIV) in nonhuman primates. This infection can lead to neurological effects and establish a viral reservoir. Given the gaps in our understanding of how these cells respond in vivo to acute CNS infection, we conducted single-cell RNA sequencing (scRNA-seq) on myeloid cells from the brains of three rhesus macaques 12 days after SIV infection, along with three uninfected controls. Our analysis revealed six distinct microglial clusters including homeostatic microglia, preactivated microglia, and activated microglia expressing high levels of inflammatory and disease-related molecules. In response to acute SIV infection, the homeostatic and preactivated microglia population decreased, while the activated and disease-related microglia increased. All microglial clusters exhibited upregulation of MHC class I molecules and interferon-related genes, indicating their crucial roles in defending against SIV during the acute phase. All microglia clusters also upregulated genes linked to cellular senescence. Additionally, we identified two distinct CAM populations: CD14lowCD16hi and CD14hiCD16low CAMs. Interestingly, during acute SIV infection, the dominant CAM population changed to one with an inflammatory phenotype. Specific upregulated genes within one microglia and one macrophage cluster were associated with neurodegenerative pathways, suggesting potential links to neurocognitive disorders. This research sheds light on the intricate interactions between viral infection, innate immune responses, and the CNS, providing valuable insights for future investigations.
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Affiliation(s)
- Xiaoke Xu
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Meng Niu
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Benjamin G Lamberty
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Katy Emanuel
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shawn Ramachandran
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Andrew J Trease
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Mehnaz Tabassum
- Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jeffrey D Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory, Frederick, Maryland, United States of America
| | - Howard S Fox
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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2
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Beliën J, Swinnen S, D'hondt R, de Juan LV, Dedoncker N, Matthys P, Bauer J, Vens C, Moylett S, Dubois B. CHIT1 at diagnosis predicts faster disability progression and reflects early microglial activation in multiple sclerosis. Nat Commun 2024; 15:5013. [PMID: 38866782 PMCID: PMC11169395 DOI: 10.1038/s41467-024-49312-y] [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: 11/09/2023] [Accepted: 05/30/2024] [Indexed: 06/14/2024] Open
Abstract
Multiple sclerosis (MS) is characterized by heterogeneity in disease course and prediction of long-term outcome remains a major challenge. Here, we investigate five myeloid markers - CHIT1, CHI3L1, sTREM2, GPNMB and CCL18 - in the cerebrospinal fluid (CSF) at diagnostic lumbar puncture in a longitudinal cohort of 192 MS patients. Through mixed-effects and machine learning models, we show that CHIT1 is a robust predictor for faster disability progression. Integrative analysis of 11 CSF and 26 central nervous system (CNS) parenchyma single-cell/nucleus RNA sequencing samples reveals CHIT1 to be predominantly expressed by microglia located in active MS lesions and enriched for lipid metabolism pathways. Furthermore, we find CHIT1 expression to accompany the transition from a homeostatic towards a more activated, MS-associated cell state in microglia. Neuropathological evaluation in post-mortem tissue from 12 MS patients confirms CHIT1 production by lipid-laden phagocytes in actively demyelinating lesions, already in early disease stages. Altogether, we provide a rationale for CHIT1 as an early biomarker for faster disability progression in MS.
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Affiliation(s)
- Jarne Beliën
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Stijn Swinnen
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Robbe D'hondt
- Department of Public Health and Primary Care, KU Leuven, Kortrijk, Belgium
- Imec research group itec, KU Leuven, Kortrijk, Belgium
| | - Laia Verdú de Juan
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Nina Dedoncker
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Patrick Matthys
- Laboratory of Immunobiology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Jan Bauer
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Celine Vens
- Department of Public Health and Primary Care, KU Leuven, Kortrijk, Belgium
- Imec research group itec, KU Leuven, Kortrijk, Belgium
| | - Sinéad Moylett
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Bénédicte Dubois
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium.
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium.
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3
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Xu X, Niu M, Lamberty BG, Emanuel K, Trease AJ, Tabassum M, Lifson JD, Fox HS. Microglia and macrophages alterations in the CNS during acute SIV infection: a single-cell analysis in rhesus macaques. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588047. [PMID: 38617282 PMCID: PMC11014596 DOI: 10.1101/2024.04.04.588047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Human Immunodeficiency Virus (HIV) is widely acknowledged for its profound impact on the immune system. Although HIV primarily affects peripheral CD4 T cells, its influence on the central nervous system (CNS) cannot be overlooked. Within the brain, microglia and CNS-associated macrophages (CAMs) serve as the primary targets for HIV, as well as for the simian immunodeficiency virus (SIV) in nonhuman primates. This infection can lead to neurological effects and the establishment of a viral reservoir. Given the gaps in our understanding of how these cells respond in vivo to acute CNS infection, we conducted single-cell RNA sequencing (scRNA-seq) on myeloid cells from the brains of three rhesus macaques 12-days after SIV infection, along with three uninfected controls. Our analysis revealed six distinct microglial clusters including homeostatic microglia, preactivated microglia, and activated microglia expressing high levels of inflammatory and disease-related molecules. In response to acute SIV infection, the population of homeostatic and preactivated microglia decreased, while the activated and disease-related microglia increased. All microglial clusters exhibited upregulation of MHC class I molecules and interferon-related genes, indicating their crucial roles in defending against SIV during the acute phase. All microglia clusters also upregulated genes linked to cellular senescence. Additionally, we identified two distinct CAM populations: CD14lowCD16hi and CD14hiCD16low CAMs. Interestingly, during acute SIV infection, the dominant CAM population changed to one with an inflammatory phenotype. Notably, specific upregulated genes within one microglia and one macrophage cluster were associated with neurodegenerative pathways, suggesting potential links to neurocognitive disorders. This research sheds light on the intricate interactions between viral infection, innate immune responses, and the CNS, providing valuable insights for future investigations.
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Affiliation(s)
- Xiaoke Xu
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Meng Niu
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Benjamin G. Lamberty
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Katy Emanuel
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Andrew J. Trease
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Mehnaz Tabassum
- Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory, Frederick, Maryland, USA
| | - Howard S. Fox
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
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4
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Kodali MC, Antone J, Alsop E, Jayakumar R, Parikh K, Chiot A, Sanchez-Molina P, Ajami B, Arnold SE, Jensen K, Das S, Weinberg MS. Cryopreservation of cerebrospinal fluid cells preserves the transcriptional landscape for single-cell analysis. J Neuroinflammation 2024; 21:71. [PMID: 38521932 PMCID: PMC10960996 DOI: 10.1186/s12974-024-03047-1] [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: 10/04/2023] [Accepted: 02/14/2024] [Indexed: 03/25/2024] Open
Abstract
Cerebrospinal fluid (CSF) matrix biomarkers have become increasingly valuable surrogate markers of neuropsychiatric diseases in research and clinical practice. In contrast, CSF cells have been rarely investigated due to their relative scarcity and fragility, and lack of common collection and cryopreservation protocols, with limited exceptions for neurooncology and primary immune-based diseases like multiple sclerosis. the advent of a microfluidics-based multi-omics approach to studying individual cells has allowed for the study of cellular phenotyping, intracellular dynamics, and intercellular relationships that provide multidimensionality unable to be obtained through acellular fluid-phase analyses. challenges to cell-based research include site-to-site differences in handling, storage, and thawing methods, which can lead to inaccuracy and inter-assay variability. In the present study, we performed single-cell RNA sequencing (10x Genomics) on fresh or previously cryopreserved human CSF samples from three alternative cryopreservation methods: Fetal Bovine Serum with Dimethyl sulfoxide (FBS/DMSO), FBS/DMSO after a DNase step (a step often included in epigenetic studies), and cryopreservation using commercially available Recovery© media. In comparing relative differences between fresh and cryopreserved samples, we found little effect of the cryopreservation method on being able to resolve donor-linked cell type proportions, markers of cellular stress, and overall gene expression at the single-cell level, whereas donor-specific differences were readily discernable. We further demonstrate the compatibility of fresh and cryopreserved CSF immune cell sequencing using biologically relevant sexually dimorphic gene expression differences by donor. Our findings support the utility and interchangeability of FBS/DMSO and Recovery cryopreservation with fresh sample analysis, providing a methodological grounding that will enable researchers to further expand our understanding of the CSF immune cell contributions to neurological and psychiatric disease.
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Affiliation(s)
- Mahesh Chandra Kodali
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
| | - Jerry Antone
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Eric Alsop
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | | | - Khushi Parikh
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Aude Chiot
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
- Department of Behavioral and Systems Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Paula Sanchez-Molina
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
- Department of Behavioral and Systems Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Bahareh Ajami
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
- Department of Behavioral and Systems Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Steven E Arnold
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Kendall Jensen
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Sudeshna Das
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Marc S Weinberg
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.
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5
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He Z, Chen Q, Wang K, Lin J, Peng Y, Zhang J, Yan X, Jie Y. Single-cell transcriptomics analysis of cellular heterogeneity and immune mechanisms in neurodegenerative diseases. Eur J Neurosci 2024; 59:333-357. [PMID: 38221677 DOI: 10.1111/ejn.16242] [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: 05/17/2023] [Revised: 12/04/2023] [Accepted: 12/12/2023] [Indexed: 01/16/2024]
Abstract
Single-cell transcriptomics analysis is an advanced technology that can describe the intracellular transcriptome in complex tissues. It profiles and analyses datasets by single-cell RNA sequencing. Neurodegenerative diseases are identified by the abnormal apoptosis of neurons in the brain with few or no effective therapy strategies at present, which has been a growing healthcare concern and brought a great burden to society. The transcriptome of individual cells provides deep insights into previously unforeseen cellular heterogeneity and gene expression differences in neurodegenerative disorders. It detects multiple cell subsets and functional changes during pathological progression, which deepens the understanding of the molecular underpinnings and cellular basis of neurodegenerative diseases. Furthermore, the transcriptome analysis of immune cells shows the regulation of immune response. Different subtypes of immune cells and their interaction are found to contribute to disease progression. This finding enables the discovery of novel targets and biomarkers for early diagnosis. In this review, we emphasize the principles of the technology, and its recent progress in the study of cellular heterogeneity and immune mechanisms in neurodegenerative diseases. The application of single-cell transcriptomics analysis in neurodegenerative disorders would help explore the pathogenesis of these diseases and develop novel therapeutic methods.
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Affiliation(s)
- Ziping He
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Medicine Eight-Year Program, Xiangya School of Medicine, Central South University, Changsha, China
| | - Qianqian Chen
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
| | - Kaiyue Wang
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
- Clinical Medicine Eight-Year Program, Xiangya School of Medicine, Central South University, Changsha, China
| | - Jiang Lin
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
| | - Yilin Peng
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
| | - Jinlong Zhang
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, China
| | - Xisheng Yan
- Department of Cardiovascular Medicine, Wuhan Third Hospital & Tongren Hospital of Wuhan University, Wuhan, China
| | - Yan Jie
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, China
- Department of Forensic Science, School of Basic Medical Science, Xinjiang Medical University, Urumqi, China
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6
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Robinson JA, Niu M, Fox HS, Burdo TH. Antiretroviral Therapy Ameliorates Simian Immunodeficiency Virus-Associated Myocardial Inflammation by Dampening Interferon Signaling and Pathogen Response in the Heart. J Infect Dis 2023; 228:276-280. [PMID: 37073617 PMCID: PMC10686685 DOI: 10.1093/infdis/jiad105] [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: 11/16/2022] [Revised: 04/04/2023] [Accepted: 04/13/2023] [Indexed: 04/20/2023] Open
Abstract
People with human immunodeficiency virus have an increased risk of developing cardiovascular disease. RNA-Seq was performed on hearts from simian immunodeficiency virus (SIV)-infected rhesus macaques with or without antiretroviral therapy (ART). SIV infection led to high plasma viral load with very little myocardial viral RNA. SIV infection promoted an inflammatory environment in the heart through interferon and pathogen signaling, in the absence of myocardial viral RNA. While ART dampened interferon and cytokine response in the heart, SIV-infected animals receiving ART had deficits in the expression of genes directly involved in fatty acid metabolism relative to SIV-uninfected animals.
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Affiliation(s)
- Jake A Robinson
- Department of Microbiology, Immunology, and Inflammation, Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Meng Niu
- Department of Genetics, Cell Biology and Anatomy, and Bioinformatics and Systems Biology Core, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Howard S Fox
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Tricia H Burdo
- Department of Microbiology, Immunology, and Inflammation, Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
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7
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Fox HS, Niu M, Morsey BM, Lamberty BG, Emanuel K, Periyasamy P, Callen S, Acharya A, Kubik G, Eudy J, Guda C, Dyavar SR, Fletcher CV, Byrareddy SN, Buch S. Morphine suppresses peripheral responses and transforms brain myeloid gene expression to favor neuropathogenesis in SIV infection. Front Immunol 2022; 13:1012884. [PMID: 36466814 PMCID: PMC9709286 DOI: 10.3389/fimmu.2022.1012884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 10/31/2022] [Indexed: 11/18/2022] Open
Abstract
The twin pandemics of opioid abuse and HIV infection can have devastating effects on physiological systems, including on the brain. Our previous work found that morphine increased the viral reservoir in the brains of treated SIV-infected macaques. In this study, we investigated the interaction of morphine and SIV to identify novel host-specific targets using a multimodal approach. We probed systemic parameters and performed single-cell examination of the targets for infection in the brain, microglia and macrophages. Morphine treatment created an immunosuppressive environment, blunting initial responses to infection, which persisted during antiretroviral treatment. Antiretroviral drug concentrations and penetration into the cerebrospinal fluid and brain were unchanged by morphine treatment. Interestingly, the transcriptional signature of both microglia and brain macrophages was transformed to one of a neurodegenerative phenotype. Notably, the expression of osteopontin, a pleiotropic cytokine, was significantly elevated in microglia. This was especially notable in the white matter, which is also dually affected by HIV and opioids. Increased osteopontin expression was linked to numerous HIV neuropathogenic mechanisms, including those that can maintain a viral reservoir. The opioid morphine is detrimental to SIV/HIV infection, especially in the brain.
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Affiliation(s)
- Howard S. Fox
- Departments of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, United States,*Correspondence: Howard S. Fox,
| | - Meng Niu
- Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Brenda M. Morsey
- Departments of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Benjamin G. Lamberty
- Departments of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Katy Emanuel
- Departments of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Palsamy Periyasamy
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
| | - Shannon Callen
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
| | - Arpan Acharya
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
| | - Gregory Kubik
- The Genomics Core Facility, University of Nebraska Medical Center, Omaha, NE, United States
| | - James Eudy
- Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Chittibabu Guda
- Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Shetty Ravi Dyavar
- The Antiviral Pharmacology Laboratory, University of Nebraska Medical Center, Omaha, NE, United States
| | - Courtney V. Fletcher
- The Antiviral Pharmacology Laboratory, University of Nebraska Medical Center, Omaha, NE, United States
| | - Siddappa N. Byrareddy
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
| | - Shilpa Buch
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
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8
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Trease AJ, Niu M, Morsey B, Guda C, Byrareddy SN, Buch S, Fox HS. Antiretroviral therapy restores the homeostatic state of microglia in SIV-infected rhesus macaques. J Leukoc Biol 2022; 112:969-981. [PMID: 35686500 PMCID: PMC9796061 DOI: 10.1002/jlb.3hi0422-635r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/11/2022] [Indexed: 12/31/2022] Open
Abstract
Microglia and macrophages are essential for homeostatic maintenance and innate immune response in the brain. They are the first line of defense against infections such as HIV/SIV in the brain. However, they are susceptible to infection and function as viral reservoirs even under effective viral suppression. While current antiretroviral regimens successfully suppress viremia and improve quality of life and lifespan, neurologic complications persist and are in part attributed to activated microglia. We sought to test the hypothesis that brain microglia return to a more homeostatic-like state when viremia is suppressed by combination antiretroviral therapy. Using the SIV-rhesus macaque model, we combined single-cell RNA sequencing, bioinformatics, and pathway analysis to compare gene expression profiles of brain myeloid cells under 4 conditions: uninfected, SIV infected, SIV infected with cART suppression, and SIV encephalitis (SIVE). Our study reveals greater myeloid diversity and an elevated proinflammatory state are associated with untreated SIV infection compared with uninfected animals. The development of encephalitis and suppression of viremia both reduced myeloid diversity. However, they had converse effects on the activation state of microglia and inflammation. Notably, suggestive of a restoration of a homeostatic state in microglia, gene expression and activation of pathways related to inflammation and immune response in cART-suppressed monkeys were most similar to that in uninfected monkeys. Untreated SIV infection shared characteristics, especially in brain macrophages to SIVE, with SIVE showing dramatic inflammation. In support of our hypothesis, our study demonstrates that cART indeed restores this key component of the brain's homeostatic state. Summary: ScRNA-seq of rhesus monkey microglia reveals clusters of cells in activated states in the setting of SIV infection, which is primarily reversed by suppressing viremia with combination antiretroviral therapy.
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Affiliation(s)
- Andrew J. Trease
- Department of Neurological SciencesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Meng Niu
- Department of Genetics, Cell Biology and AnatomyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Brenda Morsey
- Department of Neurological SciencesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Chittibabu Guda
- Department of Genetics, Cell Biology and AnatomyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Siddappa N. Byrareddy
- Department of Pharmacology and Experimental NeuroscienceUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Shilpa Buch
- Department of Pharmacology and Experimental NeuroscienceUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Howard S. Fox
- Department of Neurological SciencesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
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9
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Abstract
The single-cell revolution in the field of genomics is in full bloom, with clever new molecular biology tricks appearing regularly that allow researchers to explore new modalities or scale up their projects to millions of cells and beyond. Techniques abound to measure RNA expression, DNA alterations, protein abundance, chromatin accessibility, and more, all with single-cell resolution and often in combination. Despite such a rapidly changing technology landscape, there are several fundamental principles that are applicable to the majority of experimental workflows to help users avoid pitfalls and exploit the advantages of the chosen platform. In this overview article, we describe a variety of popular single-cell genomics technologies and address some common questions pertaining to study design, sample preparation, quality control, and sequencing strategy. As the majority of relevant publications currently revolve around single-cell RNA-seq, we will prioritize this genomics modality in our discussion. © 2022 Wiley Periodicals LLC.
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Affiliation(s)
- Claire Regan
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
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10
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Muskovic W, Powell JE. DropletQC: improved identification of empty droplets and damaged cells in single-cell RNA-seq data. Genome Biol 2021; 22:329. [PMID: 34857027 PMCID: PMC8641258 DOI: 10.1186/s13059-021-02547-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/19/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Advances in droplet-based single-cell RNA-sequencing (scRNA-seq) have dramatically increased throughput, allowing tens of thousands of cells to be routinely sequenced in a single experiment. In addition to cells, droplets capture cell-free "ambient" RNA predominantly caused by lysis of cells during sample preparation. Samples with high ambient RNA concentration can create challenges in accurately distinguishing cell-containing droplets and droplets containing ambient RNA. Current methods to separate these groups often retain a significant number of droplets that do not contain cells or empty droplets. Additionally, there are currently no methods available to detect droplets containing damaged cells, which comprise partially lysed cells, the original source of the ambient RNA. RESULTS Here, we describe DropletQC, a new method that is able to detect empty droplets, damaged, and intact cells, and accurately distinguish them from one another. This approach is based on a novel quality control metric, the nuclear fraction, which quantifies for each droplet the fraction of RNA originating from unspliced, nuclear pre-mRNA. We demonstrate how DropletQC provides a powerful extension to existing computational methods for identifying empty droplets such as EmptyDrops. CONCLUSIONS We implement DropletQC as an R package, which can be easily integrated into existing single-cell analysis workflows.
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Affiliation(s)
- Walter Muskovic
- Garvan Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst, NSW 2010 Australia
| | - Joseph E. Powell
- Garvan Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst, NSW 2010 Australia
- UNSW Cellular Genomics Futures Institute, University of New South Wales, Sydney, NSW 2052 Australia
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11
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Machado L, Relaix F, Mourikis P. Stress relief: emerging methods to mitigate dissociation-induced artefacts. Trends Cell Biol 2021; 31:888-897. [PMID: 34074577 DOI: 10.1016/j.tcb.2021.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 12/29/2022]
Abstract
The rapid progress of single-cell RNA-sequencing (scRNA-seq) at large scales has led to what seemed impossible until recently: the generation of comprehensive transcriptional maps of nearly all cells in multicellular tissues. We pinpoint three key elements as being critical to the production of these maps: scalability, spatial information, and accuracy of the transcriptome of the individual cells. Here, we discuss the ramifications of traditional cell-isolation protocols when capturing the transcriptional signature of cells as they exist in their native tissue context, the methods that have been developed to avoid these distortions, and the biological processes that have unraveled on account of these upgraded methodological approaches.
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Affiliation(s)
- Léo Machado
- Université Paris Est Créteil, Institut National de la Santé et de la Recherche Médicale (INSERM), Mondor Institute for Biomedical Research (IMRB), F-94010 Créteil, France
| | - Frederic Relaix
- Université Paris Est Créteil, Institut National de la Santé et de la Recherche Médicale (INSERM), Mondor Institute for Biomedical Research (IMRB), F-94010 Créteil, France; EnvA, IMRB, F-94700 Maisons-Alfort, France; Etablissement Français du Sang (EFS), IMRB, F-94010 Creteil, France; Assistance Publique-Hôpitaux de Paris, Hopital Mondor, Service d'Histologie, F-94010 Creteil, France.
| | - Philippos Mourikis
- Université Paris Est Créteil, Institut National de la Santé et de la Recherche Médicale (INSERM), Mondor Institute for Biomedical Research (IMRB), F-94010 Créteil, France.
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