Project description:Dengue virus is the most common arbovirus worldwide and represents a significant public health concern. To date, chronic Dengue infections have not been previously reported. While investigating the etiology of central nervous system (CNS) disease in a patient presenting with progressive dementia, we elucidated a chronic dengue infection within the CNS. Comprehensive viral immune responses in both serum and cerebrospinal fluid (CSF) were profiled by a phage-display assay (VirScan). Enrichment of Dengue viral antibodies were detected in the CSF as compared to the serum. No virus was detected in serum or CSF, but post-mortem analysis confirmed Dengue virus in the brain by quantitative polymerase chain reaction (PCR), immunohistochemistry, RNAscope and sequencing. Dengue virus was detectable by PCR and sequencing from brain biopsy tissue collected 33 months ante-mortem, confirming a chronic infection. Comprehensive antibody profiling assays can aid in the diagnosis of encephalitis of unknown etiologies. Our findings suggest that Dengue virus infections may persist in the CNS and should be considered in patients with progressive dementia in endemic regions or with relevant travel history.
Project description:ObjectiveTo determine the underlying etiology in a patient with progressive dementia with extrapyramidal signs and chronic inflammation referred to the National Institutes of Health Undiagnosed Diseases Program.MethodsExtensive investigations included metabolic profile, autoantibody panel, infectious etiologies, genetic screening, whole exome sequencing, and the phage-display assay, VirScan, for viral immune responses. An etiological diagnosis was established postmortem.ResultsUsing VirScan, enrichment of dengue viral antibodies was detected in cerebrospinal fluid as compared to serum. No virus was detected in serum or cerebrospinal fluid, but postmortem analysis confirmed dengue virus in the brain by immunohistochemistry, in situ hybridization, quantitative polymerase chain reaction, and sequencing. Dengue virus was also detectable by polymerase chain reaction and sequencing from brain biopsy tissue collected 33 months antemortem, confirming a chronic infection despite a robust immune response directed against the virus. Immunoprofiling and whole exome sequencing of the patient did not reveal any immunodeficiency, and sequencing of the virus demonstrated wild-type dengue virus in the central nervous system.InterpretationDengue virus is the most common arbovirus worldwide and represents a significant public health concern. Infections with dengue virus are usually self-limiting, and chronic dengue infections have not been previously reported. Our findings suggest that dengue virus infections may persist in the central nervous system causing a panencephalitis and should be considered in patients with progressive dementia with extrapyramidal features in endemic regions or with relevant travel history. Furthermore, this work highlights the utility of comprehensive antibody profiling assays to aid in the diagnosis of encephalitis of unknown etiology. ANN NEUROL 2019;86:695-703.
Project description:Compared to patients with no TBI history, patients with a TBI history at least one month before infectious encephalitis have an increased risk of mortality, epilepsy, and dementia or delirium. Those with a history of TBI have an increased risk of various outcomes, including mortality, epilepsy, and dementia. Bulk RNA sequencing of the hippocampus from mice subjected to CCI injury and VEEV infection demonstrated that key pathways, specifically those involved in granzyme-mediated cell death, were enriched compared to VEEV infection alone.
Project description:Dengue encephalitis, as one of the severe neurological manifestations of dengue virus infection, increasingly recognized for its rising incidence and significant public health implications. However, the pathophysiological mechanisms underlying dengue encephalitis remain inadequately elucidated, and effective prophylactic or therapeutic strategies are notably absent. In this study, we employed single-nucleus RNA sequencing to construct a comprehensive atlas of dengue encephalitis, utilizing brain tissues from dengue virus-infected murine models.
Project description:Finding the differences in gene expression in three regions of the brai, basal ganglia, white matter, and frontal cortex, in normal, HIV infected, HIV inefected with neurocognitive impairment, and HIV infected with both neurocognitive impairment and encephalitis patients. We used microarrays to identify differentially expressed genes in normal, HIV infected, HIV inefected with neurocognitive impairment, and HIV infected with both neurocognitive impairment and encephalitis patients. Samples from three different brain regions from normal, HIV infected, HIV infected with neurocognitive impairment (HAD: HIV-associated dementia), and HIV infected with both neurocognitive impairment and encephalitis (HIVE: HIV encephalitis) patients were collected for RNA isolation and supsequent Affymetrix microarray analysis. We sought to obtain gene expression levels in different brain regions to find implication of HIV and the neurological impairment and inflammation associated with HIV infection.
Project description:Rasmussen encephalitis is a unilateral encephalitis characterized by treatment-resistant epilepsy and progressive cognitive and motor decline. MRI reveals inflammation and neuropathology reveals reactive astrocytes, microglial activation, microglial nodules, T cell infiltration, and neuronal loss.
Despite the abundant evidence of altered signaling pathways in Rasmussen brain tissue and associated genetic variants, the mechanisms remain poorly understood, and it is uncertain which are a part or result of the underlying cause
In Rasmussen brain tissue, we identified by RNAseq altered immune signaling pathways, immune cell type annotation enrichment, and by whole exome sequencing HLA variants more common to Rasmussen. These findings demonstrate immune cell infiltration associated with innate and adaptive immune responses, as well as HLA variants that may increase vulnerability to RE.
Project description:HIV-associated dementia (HAD) is a syndrome occurring in HIV-infected patients with advanced disease that likely develops as a result of macrophage and microglial activation as well as other immune events triggered by virus in the central nervous system. The most relevant experimental model of HAD, rhesus macaques exhibiting SIV encephalitis (SIVE), closely reproduces the human disease and has been successfully used to advance our understanding of mechanisms underlying HAD. In this study we integrate gene expression data from uninfected and SIV-infected hippocampus with a human protein interaction network and discover modules of genes whose expression patterns distinguish these two states, to facilitate identification of neuronal genes that may contribute to SIVE/HIV cognitive deficits. Using this approach we identify several downregulated candidate genes and select one, EGR1, a key molecule in hippocampus-related learning and memory, for further study. We show that EGR1 is downregulated in SIV-infected hippocampus and that it can be downregulated in differentiated human neuroblastoma cells by treatment with CCL8, a product of activated microglia. Integration of expression data with protein interaction data to discover discriminatory modules of interacting proteins can be usefully employed to prioritize differentially expressed genes for further study. Investigation of EGR1, selected in this manner, indicates that its downregulation in SIVE may occur as a consequence of the host response to infection, leading to deficits in cognition. RNA from duplicate hippocampal samples taken from nine control monkeys and nine monkeys with evidence of SIV encephalitis were hybridized to Affymetrix arrays.
Project description:Around 25% of stroke survivors over 65 years old develop progressive cognitive decline more than 3 months post-stroke, with features of vascular dementia. Poststroke dementia (PSD) is associated with pathology in frontal brain regions, in particular dorsal lateral prefrontal cortex (DLPFC) neurons and white matter, remote from the infarct, implicating damage to anterior cognitive circuits (ACC) involved in impaired executive function. We hypothesised that PSD results from progressive neuronal damage in the DLPFC and that this is associated with alterations in the gliovascular unit (GVU) of frontal white matter. We aimed to identify the cellular and molecular basis of PSD by investigating the transcriptomic profile of the neurons and white matter GVU cells previously implicated in pathology. Laser capture microdissected neurons, astrocytes and endothelial cells were obtained from the Cognitive Function After Stroke (COGFAST) cohort. Gene expression was assessed using microarrays and pathways analysis to compare changes in PSD with controls and with poststroke non-dementia (PSND). Laser captured microdissected neurons were obtained from the bilateral carotid artery stenosis (BCAS) model and equivalent SHAM animals