Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is an RNA virus responsible for coronavirus disease 2019 (COVID-19). While SARS-CoV-2 primarily targets the lungs and airways, it can also infect other organs, including the central nervous system (CNS). The aim of this study was to investigate whether the choroid plexus could serve as a potential entry site for SARS-CoV-2 into the brain. Tissue samples from 24 deceased COVID-19-positive individuals were analyzed. Reverse transcription real-time PCR (RT-qPCR) was performed on selected brain regions, including the choroid plexus, to detect SARS-CoV-2 viral RNA. Additionally, immunofluorescence staining and confocal microscopy were used to detect and localize two characteristic proteins of SARS-CoV-2: the spike protein S1 and the nucleocapsid protein. RT-qPCR analysis confirmed the presence of SARS-CoV-2 viral RNA in the choroid plexus. Immunohistochemical staining revealed viral particles localized in the epithelial cells of the choroid plexus, with the spike protein S1 detected in the late endosomes. Our findings suggest that the blood-cerebrospinal fluid (B-CSF) barrier in the choroid plexus serves as a route of entry for SARS-CoV-2 into the CNS. This study contributes to the understanding of the mechanisms underlying CNS involvement in COVID-19 and highlights the importance of further research to explore potential therapeutic strategies targeting this entry pathway.
- MeSH
- COVID-19 * virology MeSH
- Adult MeSH
- Phosphoproteins * metabolism MeSH
- Spike Glycoprotein, Coronavirus * genetics metabolism MeSH
- Blood-Brain Barrier * virology MeSH
- Virus Internalization MeSH
- Coronavirus Nucleocapsid Proteins MeSH
- Middle Aged MeSH
- Humans MeSH
- Choroid Plexus * virology MeSH
- RNA, Viral * genetics MeSH
- SARS-CoV-2 * physiology MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: The choroid plexus (ChP) is the secretory epithelial structure located in the brain ventricles. Choroid plexus tumors (CPTs) are rare neoplasms predominantly occurring in young patients with intensified malignancy in children. CPT treatment is hindered by insufficient knowledge of tumor pathology and the limited availability of valid models. METHODS: Genomic and transcriptomic data from CPT patients were analyzed to identify the putative pathological pathway. Cellular and molecular techniques were employed to validate bioinformatic results in CPT patient samples. Pharmacologic inhibition of Wnt/β-catenin signaling was assessed in CPT cells. Cell-based assays of ChP cell lines were performed following CRISPR-Cas9-derived knockout and overexpression of Wnt/β-catenin pathway genes. A 3D CPT model was generated through CRISPR-Cas9-derived knockout of APC. RESULTS: We discovered that Wnt/β-catenin signaling is activated in human CPTs, likely as a consequence of large-scale chromosomal instability events of the CPT genomes. We demonstrated that CPT-derived cells depend on autocrine Wnt/β-catenin signaling for survival. Constitutive Wnt/β-catenin pathway activation, either through knockout of the negative regulator APC or overexpression of the ligand WNT3A, induced tumorigenic properties in ChP 2D in vitro models. Increased activation of the Wnt/β-catenin pathway in ChP organoids, through treatment with a potent GSK3β inhibitor, reduced the differentiation of mature ChP epithelial cells. Remarkably, the depletion of APC was sufficient to induce the oncogenic transformation of ChP organoids. CONCLUSIONS: Our research identifies Wnt/β-catenin signaling as a critical driver of CPT tumorigenesis and provides the first 3D in vitro model for future pathological and therapeutic studies of CPT.
- MeSH
- beta Catenin metabolism genetics MeSH
- Carcinogenesis metabolism MeSH
- Humans MeSH
- Tumor Cells, Cultured MeSH
- Choroid Plexus Neoplasms * pathology metabolism genetics MeSH
- Choroid Plexus metabolism pathology MeSH
- Cell Proliferation MeSH
- Gene Expression Regulation, Neoplastic MeSH
- Wnt Signaling Pathway * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Choroid plexus (ChP), the brain structure primarily responsible for cerebrospinal fluid production, contains a robust circadian clock, whose role remains to be elucidated. The aim of our study was to [1] identify rhythmically controlled cellular processes in the mouse ChP and [2] assess the role and nature of signals derived from the master clock in the suprachiasmatic nuclei (SCN) that control ChP rhythms. To accomplish this goal, we used various mouse models (WT, mPer2Luc, ChP-specific Bmal1 knockout) and combined multiple experimental approaches, including surgical lesion of the SCN (SCNx), time-resolved transcriptomics, and single cell luminescence microscopy. In ChP of control (Ctrl) mice collected every 4 h over 2 circadian cycles in darkness, we found that the ChP clock regulates many processes, including the cerebrospinal fluid circadian secretome, precisely times endoplasmic reticulum stress response, and controls genes involved in neurodegenerative diseases (Alzheimer's disease, Huntington's disease, and frontotemporal dementia). In ChP of SCNx mice, the rhythmicity detected in vivo and ex vivo was severely dampened to a comparable extent as in mice with ChP-specific Bmal1 knockout, and the dampened cellular rhythms were restored by daily injections of dexamethasone in mice. Our data demonstrate that the ChP clock controls tissue-specific gene expression and is strongly dependent on the presence of a functional connection with the SCN. The results may contribute to the search for a novel link between ChP clock disruption and impaired brain health.
- MeSH
- Circadian Clocks * physiology MeSH
- Circadian Rhythm physiology MeSH
- Mice, Inbred C57BL MeSH
- Mice, Knockout MeSH
- Mice MeSH
- Suprachiasmatic Nucleus * metabolism physiology MeSH
- Choroid Plexus * metabolism physiology MeSH
- ARNTL Transcription Factors metabolism genetics MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The choroid plexus (ChP) in the brain ventricles has a major influence on brain homeostasis. In this study, we aimed to determine whether the circadian clock located in ChP is affected by chronodisruption caused by misalignment with the external light/dark cycle and/or inflammation. Adult mPer2Luc mice were maintained in the LD12:12 cycle or exposed to one of two models of chronic chronodisruption - constant light for 22-25 weeks (cLL) or 6-hour phase advances of the LD12:12 cycle repeated weekly for 12 weeks (cLD-shifts). Locomotor activity was monitored before the 4th ventricle ChP and suprachiasmatic nuclei (SCN) explants were recorded in real time for PER2-driven population and single-cell bioluminescence rhythms. In addition, plasma immune marker concentrations and gene expression in ChP, prefrontal cortex, hippocampus and cerebellum were analyzed. cLL dampened the SCN clock but did not shorten the inactivity interval (sleep). cLD-shifts had no effect on the SCN clock, but transiently affected sleep duration and fragmentation. Both chronodisruption protocols dampened the ChP clock. Although immune markers were elevated in plasma and hippocampus, levels in ChP were unaffected, and unlike the liver clock, the ChP clock was resistant to lipopolysaccharide treatment. Importantly, both chronodisruption protocols reduced glucocorticoid signaling in ChP. The data demonstrate the high resistance of the ChP clock to inflammation, highlighting its role in protecting the brain from neuroinflammation, and on the other hand its high sensitivity to chronodisruption. Our results provide a novel link between human lifestyle-induced chronodisruption and the impairment of ChP-dependent brain homeostasis.
- MeSH
- Leukemia, Lymphocytic, Chronic, B-Cell * MeSH
- Circadian Clocks * MeSH
- Period Circadian Proteins genetics metabolism MeSH
- Circadian Rhythm physiology MeSH
- Humans MeSH
- Mice MeSH
- Choroid Plexus metabolism MeSH
- Inflammation MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The choroid plexus (ChP) produces and is bathed in the cerebrospinal fluid (CSF), which in aging and Alzheimer's disease (AD) shows extensive proteomic alterations including evidence of inflammation. Considering inflammation hampers functions of the involved tissues, the CSF abnormalities reported in these conditions are suggestive of ChP injury. Indeed, several studies document ChP damage in aging and AD, which nevertheless remains to be systematically characterized. We here report that the changes elicited in the CSF by AD are consistent with a perturbed aging process and accompanied by aberrant accumulation of inflammatory signals and metabolically active proteins in the ChP. Magnetic resonance imaging (MRI) imaging shows that these molecular aberrancies correspond to significant remodeling of ChP in AD, which correlates with aging and cognitive decline. Collectively, our preliminary post-mortem and in vivo findings reveal a repertoire of ChP pathologies indicative of its dysfunction and involvement in the pathogenesis of AD. HIGHLIGHTS: Cerebrospinal fluid changes associated with aging are perturbed in Alzheimer's disease Paradoxically, in Alzheimer's disease, the choroid plexus exhibits increased cytokine levels without evidence of inflammatory activation or infiltrates In Alzheimer's disease, increased choroid plexus volumes correlate with age and cognitive performance.
The choroid plexus (ChP) is part of the blood-cerebrospinal fluid barrier, regulating brain homeostasis and the brain's response to peripheral events. Its upregulation and enlargement are considered essential in psychosis. However, the timing of the ChP enlargement has not been established. This study introduces a novel magnetic resonance imaging-based segmentation method to examine ChP volumes in two cohorts of individuals with psychosis. The first sample consists of 41 individuals with early course psychosis (mean duration of illness = 1.78 years) and 30 healthy individuals. The second sample consists of 30 individuals with chronic psychosis (mean duration of illness = 7.96 years) and 34 healthy individuals. We utilized manual segmentation to measure ChP volumes. We applied ANCOVAs to compare normalized ChP volumes between groups and partial correlations to investigate the relationship between ChP, LV volumes, and clinical characteristics. Our segmentation demonstrated good reliability (.87). We further showed a significant ChP volume increase in early psychosis (left: p < .00010, right: p < .00010) and a significant positive correlation between higher ChP and higher LV volumes in chronic psychosis (left: r = .54, p = .0030, right: r = .68; p < .0010). Our study suggests that ChP enlargement may be a marker of acute response around disease onset. It might also play a modulatory role in the chronic enlargement of lateral ventricles, often reported in psychosis. Future longitudinal studies should investigate the dynamics of ChP enlargement as a promising marker for novel therapeutic strategies.
- MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Brain pathology MeSH
- Choroid Plexus * diagnostic imaging pathology MeSH
- Psychotic Disorders * diagnostic imaging pathology MeSH
- Reproducibility of Results MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
Lithium is an effective mood stabilizer, but the mechanism of its therapeutic action is not well understood. We investigated the effect of lithium on the circadian clock located in the ventricle barrier complex containing the choroid plexus (CP), a part of the glymphatic system that influences gross brain function via the production of cerebrospinal fluid. The mPer2Luc mice were injected with lithium chloride (LiCl) or vehicle, and their effects on the clock gene Nr1d1 in CP were detected by RT qPCR. CP organotypic explants were prepared to monitor bioluminescence rhythms in real time and examine the responses of the CP clock to LiCl and inhibitors of glycogen synthase kinase-3 (CHIR-99021) and protein kinase C (chelerythrine). LiCl affected Nr1d1 expression levels in CP in vivo and dose-dependently delayed the phase and prolonged the period of the CP clock in vitro. LiCl and CHIR-99021 had different effects on 1] CP clock parameters (amplitude, period, phase), 2] dexamethasone-induced phase shifts of the CP clock, and 3] dynamics of PER2 degradation and de novo accumulation. LiCl-induced phase delays were significantly reduced by chelerythrine, suggesting the involvement of PKC activity. The effects on the CP clock may be involved in the therapeutic effects of lithium and hypothetically improve brain function in psychiatric patients by aligning the function of the CP clock-related glymphatic system with the sleep-wake cycle. Importantly, our data argue for personalized timing of lithium treatment in BD patients.
- MeSH
- Circadian Clocks * MeSH
- Period Circadian Proteins genetics MeSH
- Circadian Rhythm genetics MeSH
- Lithium pharmacology MeSH
- Mice MeSH
- Choroid Plexus metabolism MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- MeSH
- Circumventricular Organs physiology physiopathology MeSH
- Blood-Brain Barrier physiology physiopathology MeSH
- Humans MeSH
- Cerebrospinal Fluid * diagnostic imaging physiology MeSH
- Choroid Plexus physiology physiopathology MeSH
- Spinal Puncture methods MeSH
- Cerebrospinal Fluid Pressure physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
The epithelial cells of choroid plexus (CP) in brain ventricles produce cerebrospinal fluid and act as the blood-cerebrospinal fluid barrier. In this study, we confirmed that CP in the 4th ventricle is composed of cellular oscillators that all harbor glucocorticoid receptors and are mutually synchronized to produce a robust clock gene expression rhythm detectable at the tissue level in vivo and in vitro. Animals lacking glucocorticoids (GCs) due to surgical removal of adrenal glands had Per1, Per2, Nr1d1 and Bmal1 clock gene rhythmicity in their CP significantly dampened, whereas subjecting them to daily bouts of synthetic GC analog, dexamethasone (DEX), reinforced those rhythms. We verified these in vivo effects using an in vitro model of organotypic CP explants; depending on the time of its application, DEX significantly increased the amplitude and efficiently reset the phase of the CP clock. The results are the first description of a PRC for a non-neuronal clock in the brain, demonstrating that CP clock shares some properties with the non-neuronal clocks elsewhere in the body. Finally, we found that DEX exhibited multiple synergic effects on the CP clock, including acute activation of Per1 expression and change of PER2 protein turnover rate. The DEX-induced shifts of the CP clock were partially mediated via PKA-ERK1/2 pathway. The results provide the first evidence that the GC rhythm strengthens and entrains the clock in the CP helping thus fine-tune the brain environment according to time of day.
- MeSH
- Circadian Clocks * MeSH
- Period Circadian Proteins genetics metabolism MeSH
- Dexamethasone MeSH
- Glucocorticoids metabolism MeSH
- MAP Kinase Signaling System MeSH
- Adrenal Glands metabolism MeSH
- Suprachiasmatic Nucleus metabolism MeSH
- Choroid Plexus metabolism MeSH
- Rats, Wistar MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The choroid plexus (ChP) in each brain ventricle produces cerebrospinal fluid (CSF) and forms the blood-CSF barrier. Here, we construct a single-cell and spatial atlas of each ChP in the developing, adult, and aged mouse brain. We delineate diverse cell types, subtypes, cell states, and expression programs in epithelial and mesenchymal cells across ages and ventricles. In the developing ChP, we predict a common progenitor pool for epithelial and neuronal cells, validated by lineage tracing. Epithelial and fibroblast cells show regionalized expression by ventricle, starting at embryonic stages and persisting with age, with a dramatic transcriptional shift with maturation, and a smaller shift in each aged cell type. With aging, epithelial cells upregulate host-defense programs, and resident macrophages upregulate interleukin-1β (IL-1β) signaling genes. Our atlas reveals cellular diversity, architecture and signaling across ventricles during development, maturation, and aging of the ChP-brain barrier.
- MeSH
- Single-Cell Analysis MeSH
- Cell Differentiation genetics MeSH
- Cell Lineage genetics MeSH
- Epithelial Cells metabolism MeSH
- Blood-Brain Barrier metabolism MeSH
- Brain metabolism physiology MeSH
- Mice, Inbred C57BL MeSH
- Mice embryology MeSH
- Brain Diseases genetics physiopathology MeSH
- Choroid Plexus embryology metabolism physiology MeSH
- Signal Transduction MeSH
- Aging physiology MeSH
- Age Factors MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice embryology MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
