Dysregulation of brain and choroid plexus cell types in severe COVID-19
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ABSTRACT: Though SARS-CoV-2 primarily targets the respiratory system, patients and survivors can suffer neurological symptoms. Yet, an unbiased understanding of the cellular and molecular processes affected in the brains of COVID-19 patients is still missing. Here, we profile 65,309 single-nucleus transcriptomes from 30 frontal cortex and choroid plexus samples across 14 control (including 1 terminal influenza) and 8 COVID-19 patients. While a systematic analysis yields no molecular traces of SARS-CoV-2 in the brain, we observe broad cellular perturbations which predict that choroid plexus barrier cells sense and relay peripheral inflammation into the brain and show that peripheral T cells infiltrate the parenchyma. We discover COVID-19 disease-associated microglia and astrocyte subpopulations that share features with pathological cell states reported in human neurodegenerative disease. Synaptic signaling of upper-layer excitatory neurons—evolutionarily expanded in humans and linked to cognitive function—are preferentially affected in COVID-19. Across cell types, COVID-19 perturbations overlap with those in chronic brain disorders and reside in genetic variants associated with cognition, schizophrenia, and depression. Our findings and public dataset provide a molecular framework to understand COVID-19 related neurological disease observed now and which may emerge later.
Project description:Neurological complications are common in patients with COVID-19. While SARS-CoV-2, the causal pathogen of COVID-19, has been detected in some patient brains, its ability to infect brain cells and impact their function are not well understood, and experimental models using human brain cells are urgently needed. Here we investigated the susceptibility of human induced pluripotent stem cell (hiPSC)-derived monolayer brain cells and region-specific brain organoids to SARS-CoV-2 infection. We found modest numbers of infected neurons and astrocytes, but greater infection of choroid plexus epithelial cells. We optimized a protocol to generate choroid plexus organoids from hiPSCs, which revealed productive SARS-CoV-2 infection that leads to increased cell death and transcriptional dysregulation indicative of an inflammatory response and cellular function deficits. Together, our results provide evidence for SARS-CoV-2 neurotropism and support use of hiPSC-derived brain organoids as a platform to investigate the cellular susceptibility, disease mechanisms, and treatment strategies for SARS-CoV-2 infection.
Project description:Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has been associated with neurological and neuropsychiatric illness in many individuals. We sought to further our understanding of the relationship between brain tropism, neuro-inflammation and host immune response in acute COVID-19 cases. 3 brain regions (dorsolateral prefrontal cortex, medulla oblongata and choroid plexus) from 5 patients with severe COVID-19 and 4 controls were examined. The presence of virus was assessed by western blot against viral spike protein, as well as viral transcriptome analysis covering >99% of SARS-CoV-2 genome and all potential serotypes. Droplet-based single-nucleus RNA sequencing (snRNA-seq) was performed in the same samples to examine the impact of COVID-19 on transcription in individual cells of the brain. Quantification of viral spike S1 protein and viral transcripts did not detect SARS-CoV-2 in the postmortem brain tissue. However, analysis of 68,557 single-nucleus transcriptomes from three distinct regions of the brain identified an increased proportion of stromal cells, monocytes and macrophages in the choroid plexus of COVID-19 patients. Furthermore, differential gene expression, pseudo-temporal trajectory and gene regulatory network analyses revealed transcriptional changes in cortical microglia associated with a range of biological processes, including cellular activation, mobility and phagocytosis. Despite the absence of detectable SARS-CoV-2 in the brain at time of death, the findings suggest significant and persistent neuroinflammation in patients with acute COVID-19.
Project description:The objective of the study was to characterize the immunoreactivity profiles of IgG-reactive epitopes in COVID-19 patients with distinct disease trajectories as well as SARS-CoV-2-naïve sera, using a high-density SARS-CoV-2 whole proteome peptide microarray. The microarray comprised of a total of 5347 individual peptides, each consisting of 15 amino acids with an overlap of 13 amino acids printed in duplicate. The microarray also had a panel of the most relevant mutations from SARS-CoV-2 variants of concern like omicron, alpha, beta, gamma, delta, and others. This study consisted of 29 participants, including 10 naïve controls (5 pre-pandemic and 5 SARS-CoV-2 seronegative) and 19 RT-PCR-confirmed COVID-19 patients. The COVID-19 patients were stratified into two distinct cohorts based on their disease trajectories: the severe cohort (S), in which the patients presented moderate COVID-19 symptoms initially but eventually progressed toward severity; and the recovered cohort (R), in which severe COVID-19 patients progressed toward recovery. Our findings contribute to a deeper understanding of the immunopathogenesis of COVID-19 in patients with different disease trajectories, the effect of mutations on immunoreactivity, and potential cross-reactivity due to exposure to common cold viruses.
Project description:The numerous neurological syndromes associated with COVID-19 implicate an effect of viral pathogenesis on neuronal function, yet reports of direct SARS-CoV-2 infection in the brain are conflicting. We used a well-established organotypic brain slice culture to determine the permissivity of hamster brain tissues to SARS-CoV-2 infection. We found levels of live virus waned after inoculation and observed no evidence of cell-to-cell spread, indicating that SARS-CoV-2 infection was non-productive. Nonetheless, we identified a small number of infected cells with glial phenotypes; yet no evidence of viral infection or replication was observed in neurons. Our data corroborates several clinical studies that have assessed patients with COVID-19 and their association with neurological involvement.
Project description:Objectives: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes the worldwide COVID-19 pandemic. While SARS-CoV-2 can infect people of all ages and both sexes, senior populations are at greatest risk of severe disease and worse outcomes, and sexual dimorphism has been reported in COVID-19. COVID-19 causes damage to multiple organ systems, including the brain. Neurological symptoms are widely observed in patients with Covid-19, with many survivors suffering from persistent neurological impairment, potentially accelerating Alzheimer’s disease (AD). This study aims to investigate the mechanisms underlying the impact of age, and sex on neuroinflammation due to SARS-CoV-2 infection using mouse models. Methods: Wild-type C57BL/6 mice were subjected to intranasal inoculation of SARS-CoV-2 lineage B.1.351, followed by daily body weight monitoring. At 7 dpi, viral burden and inflammatory cytokine/chemokine responses in the lung and brain were determined by quantitative RT-PCR, followed by immunohistochemical and transcriptomic analyses. Results: Older age, male sex, showed increased lung viral loads and severity of SARS-CoV-2 infection in mice. No viral RNA was detected in the brains of infected mice; however, IL-6 and CCL2 mRNA increased significantly, particularly in brains of old and APOE4 mice. Unbiased brain RNA-seq/transcriptomic analysis showed that SARS-CoV-2 infection caused significant changes in gene expression profiles, and pathway analysis identified innate immunity and defense response to virus and other organisms as the major molecular networks affected in the brain by SARS-CoV-2 infection. Conclusions: Our findings demonstrate that age, and sex, modify the progression and outcome of SARS-CoV-2 infection. SARS-CoV-2 infection triggers neuroinflammatory responses despite the lack of detectable virus in the brain. Changes in molecular networks of innate immunity and defense response to microorganisms underlie the impact of SARS-CoV-2 infection in the brain. These findings in mice mimic epidemiological and clinical observations in humans with Covid-19.
Project description:Why individuals with Down Syndrome (DS, trisomy 21) are particularly susceptible to SARS-CoV-2 induced disease remains largely unclear. The choroid plexus secrets the cerebrospinal fluid and strongly expresses the ACE2 receptor and the chromosome 21 encoded TMPRSS2 protease. To investigate the role of the choroid plexus in SARS-CoV-2 central nervous system infection in DS, we established a new type of brain organoid from DS and isogenic euploid control iPSC that consists of a core of appropriately patterned functional cortical neuronal cell types that is surrounded by a patent and functional choroid plexus (CPCOs). Remarkably, DS-CPCOs not only recapitulated abnormal features of DS cortical development but also revealed defects in ciliogenesis and epithelial cell polarity of the developing choroid plexus. We next demonstrate that the choroid plexus layer facilitates SARS-CoV-2 replication and infection of cortical neuronal cells, and that this is increased in DS-CPCOs. We further show that inhibition of TMPRSS2 activity in DS-CPCOs inhibits SARS-CoV-2 infectivity. We conclude that CPCOs are a useful model for dissecting the role of the choroid plexus in euploid and DS forebrain development and enables screening for therapeutics that can inhibit SARS-CoV-2 induced neuro-pathogenesis.
Project description:Why individuals with Down Syndrome (DS, trisomy 21) are particularly susceptible to SARS-CoV-2 induced disease remains largely unclear. The choroid plexus secrets the cerebrospinal fluid and strongly expresses the ACE2 receptor and the chromosome 21 encoded TMPRSS2 protease. To investigate the role of the choroid plexus in SARS-CoV-2 central nervous system infection in DS, we established a new type of brain organoid from DS and isogenic euploid control iPSC that consists of a core of appropriately patterned functional cortical neuronal cell types that is surrounded by a patent and functional choroid plexus (CPCOs). Remarkably, DS-CPCOs not only recapitulated abnormal features of DS cortical development but also revealed defects in ciliogenesis and epithelial cell polarity of the developing choroid plexus. We next demonstrate that the choroid plexus layer facilitates SARS-CoV-2 replication and infection of cortical neuronal cells, and that this is increased in DS-CPCOs. We further show that inhibition of TMPRSS2 activity in DS-CPCOs inhibits SARS-CoV-2 infectivity. We conclude that CPCOs are a useful model for dissecting the role of the choroid plexus in euploid and DS forebrain development and enables screening for therapeutics that can inhibit SARS-CoV-2 induced neuro-pathogenesis.
Project description:SARS-Cov-2 infection is frequently associated with Nervous System (NS) manifestations. However, it is not clear how SARS-CoV-2 can cause neurological dysfunctions and which molecular processes affects. In this work, we examined the frontal cortex tissue of patients who died of COVID-19 for the presence of SARS-CoV-2, comparing qRT-PCR with ddPCR. We also investigated the transcriptomic profile of frontal cortex from COVID-19 patients and matched controls by RNA-seq analysis to characterize the transcriptional signature.
Project description:COVID-19 patients commonly present with neurological signs of central nervous system (CNS) and/or peripheral nervous system dysfunction. However, which neural cells are permissive to infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been controversial. Here, we show that midbrain dopamine (DA) neurons derived from human pluripotent stem cells (hPSCs) are selectively susceptible and permissive to SARS-CoV-2 infection, and that SARS-CoV-2 infection triggers a DA neuron inflammatory and cellular senescence response. A high-throughput screen in hPSC-derived DA neurons identified several FDA approved drugs, including riluzole, metformin, and imatinib, that can rescue the cellular senescence phenotype by preventing SARS-CoV-2 infection. RNA-seq analysis of human ventral midbrain tissue from COVID-19 patients, using formalin-fixed paraffin-embedded autopsy samples, confirmed the induction of an inflammatory and cellular senescence signature and identified low levels of SARS-CoV-2 transcripts. Our findings demonstrate that hPSC-derived DA neurons can serve as a disease model to study neuronal susceptibility to SARS-CoV-2 and to identify candidate neuroprotective drugs for COVID-19 patients. The susceptibility of hPSC-derived DA neurons to SARS-CoV-2 and the observed inflammatory and senescence transcriptional responses suggest the need for careful, long-term monitoring of neurological problems in COVID-19 patients.
Project description:COVID-19 patients may exhibit neuropsychiatric and neurological symptoms. We found that anxiety and cognitive impairment are manifested by 28-56% of SARS-CoV-2-infected individuals with mild respiratory symptoms and are associated with altered cerebral cortical thickness. Using an independent cohort, we found histopathological signs of brain damage in 25% of individuals who died of COVID-19. All of the affected brain tissues exhibited foci of SARS-CoV-2 infection and replication, particularly in astrocytes. Infection of neural stem cell-derived astrocytes changed energy metabolism, altered key proteins and metabolites used to fuel neurons and for biogenesis of neurotransmitters, and elicited a secretory phenotype that reduces neuronal viability. Our data support the model where SARS-CoV-2 reaches the brain, infects astrocytes and triggers neuropathological changes that contribute to the structural and functional alterations in the brain of COVID-19 patients.