Post-mortem Central Nervous System Tissue Research Articles

Soluble CD27 is an intrathecal biomarker of T-cell-mediated lesion activity in multiple sclerosis

ObjectiveSoluble CD27 is a promising cerebrospinal fluid inflammatory biomarker in multiple sclerosis. In this study, we investigate relevant immune and neuro-pathological features of soluble CD27 in multiple sclerosis.MethodsProtein levels of soluble CD27 were correlated to inflammatory cell subpopulations and inflammatory cytokines and chemokines detected in cerebrospinal fluid of 137 patients with multiple sclerosis and 47 patients with inflammatory and non-inflammatory neurological disease from three independent cohorts. Production of soluble CD27 was investigated in cell cultures of activated T and B cells and CD27-knockout T cells. In a study including matched cerebrospinal fluid and post-mortem brain tissues of patients with multiple sclerosis and control cases, levels of soluble CD27 were correlated with perivascular and meningeal infiltrates and with neuropathological features.ResultsWe demonstrate that soluble CD27 favours the differentiation of interferon-γ-producing T cells and is released through a secretory mechanism activated by TCR engagement and regulated by neutral sphingomyelinase. We also show that the levels of soluble CD27 correlate with the representation of inflammatory T cell subsets in the CSF of patients with relapsing-remitting multiple sclerosis and with the magnitude of perivascular and meningeal CD27 + CD4 + and CD8 + T cell infiltrates in post-mortem central nervous system tissue, defining a subgroup of patients with extensive active inflammatory lesions.InterpretationOur results demonstrate that soluble CD27 is a biomarker of disease activity, potentially informative for personalized treatment and monitoring of treatment outcomes.

The Role of Intercellular Adhesion Molecule-1 in the Pathogenesis of Psychiatric Disorders.

Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein that is overexpressed in many pathological states. Although, like many other immune molecules, ICAM-1 plays only a limited role in the abundant concert of the immune response, it may be more important than we realize. In the central nervous system (CNS), ICAM-1 is expressed in microglial cells and astrocytes and in endothelial cells in the white and gray matter of the human forebrain. It is of particular interest in psychiatric disorders for two reasons: It has a key function for the blood–brain barrier, which plays an important role in the biology of psychiatric disorders, and it is a marker for inflammation. Although the blood level of soluble ICAM-1 (sICAM-1) might be lower in acute unmedicated schizophrenia, it has been reported to be increased in many other psychiatric conditions, such as major depression, bipolar disorder, and dementia. In bipolar disorder, high sICAM levels were found during both the depressed and the manic states and also during the euthymic phase (the free interval), possibly indicating that sICAM is a trait marker. High sICAM-1 blood levels have also been found in depression comorbid to a somatic disease state. Interestingly, sICAM-1 levels also increase during aging. Some studies investigated sICAM-1 levels in the cerebrospinal fluid of psychiatric disorders and ICAM-1 expression in postmortem CNS tissue of psychiatric patients and found that the overall duration and duration of the chronic phase of the psychiatric disorder seem to play a role in both. Moreover, confounders, such as antipsychotic and antidepressive medication, have to be considered. sICAM-1 levels seem to be associated with hypopermeability or hyperpermeability of the blood-brain barrier and thus to influence the communication between the CNS immune system, represented by glia cells, and the peripheral immune system. The balance between the influx and efflux of immune molecules into and out of the CNS may be one of the pinpoints in psychiatric disorders, in particular in the chronic phase, e.g., in schizophrenia. This aspect, however, needs further intense research, in particular to enable researchers to develop therapeutic principles based on an immune/inflammatory approach.

Chronic Traumatic Encephalopathy Within an Amyotrophic Lateral Sclerosis Brain Bank Cohort.

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disorder linked to repetitive head impacts and has been associated with amyotrophic lateral sclerosis (ALS), a fatal, degenerative neuromuscular disorder. The Department of Veterans Affairs Biorepository Brain Bank (VABBB) is a tissue repository that collects antemortem disease progression data and postmortem central nervous system tissue from veterans with ALS. We set out to determine the frequency of co-morbid ALS and CTE in the VABBB cohort and to characterize the clinical, genetic, and pathological distinctions between participants with ALS only and those with both ALS and CTE (ALS+CTE). Of 155 participants, 9 (5.8%) had neuropathologically confirmed ALS+CTE. Participants with ALS+CTE were more likely to have a history of traumatic brain injury (p < 0.001), served during the first Persian Gulf War (p < 0.05), and to have more severe tau pathology within the frontal cortex and spinal cord (p < 0.05). The most common exposures to head impacts included contact sports (n = 5) and military service (n = 2). Clinically, participants with ALS+CTE were more likely to have bulbar onset ALS (p = 0.006), behavioral changes (p = 0.002), and/or mood changes (p < 0.001). Overall, compared with ALS in isolation, comorbid ALS+CTE is associated with a history of TBI and has a distinct clinical and pathological presentation.

Integrated multi-cohort transcriptional meta-analysis of neurodegenerative diseases.

IntroductionNeurodegenerative diseases share common pathologic features including neuroinflammation, mitochondrial dysfunction and protein aggregation, suggesting common underlying mechanisms of neurodegeneration. We undertook a meta-analysis of public gene expression data for neurodegenerative diseases to identify a common transcriptional signature of neurodegeneration.ResultsUsing 1,270 post-mortem central nervous system tissue samples from 13 patient cohorts covering four neurodegenerative diseases, we identified 243 differentially expressed genes, which were similarly dysregulated in 15 additional patient cohorts of 205 samples including seven neurodegenerative diseases. This gene signature correlated with histologic disease severity. Metallothioneins featured prominently among differentially expressed genes, and functional pathway analysis identified specific convergent themes of dysregulation. MetaCore network analyses revealed various novel candidate hub genes (e.g. STAU2). Genes associated with M1-polarized macrophages and reactive astrocytes were strongly enriched in the meta-analysis data. Evaluation of genes enriched in neurons revealed 70 down-regulated genes, over half not previously associated with neurodegeneration. Comparison with aging brain data (3 patient cohorts, 221 samples) revealed 53 of these to be unique to neurodegenerative disease, many of which are strong candidates to be important in neuropathogenesis (e.g. NDN, NAP1L2). ENCODE ChIP-seq analysis predicted common upstream transcriptional regulators not associated with normal aging (REST, RBBP5, SIN3A, SP2, YY1, ZNF143, IKZF1). Finally, we removed genes common to neurodegeneration from disease-specific gene signatures, revealing uniquely robust immune response and JAK-STAT signaling in amyotrophic lateral sclerosis.ConclusionsOur results implicate pervasive bioenergetic deficits, M1-type microglial activation and gliosis as unifying themes of neurodegeneration, and identify numerous novel genes associated with neurodegenerative processes.Electronic supplementary materialThe online version of this article (doi:10.1186/s40478-014-0093-y) contains supplementary material, which is available to authorized users.

Integrated multi-cohort transcriptional meta-analysis of neurodegenerative diseases

Neurodegenerative diseases share common pathologic features including neuroinflammation, mitochondrial dysfunction and protein aggregation, suggesting common underlying mechanisms of neurodegeneration. We undertook a meta-analysis of public gene expression data for neurodegenerative diseases to identify a common transcriptional signature of neurodegeneration. Using 1,270 post-mortem central nervous system tissue samples from 13 patient cohorts covering four neurodegenerative diseases, we identified 243 differentially expressed genes, which were similarly dysregulated in 15 additional patient cohorts of 205 samples including seven neurodegenerative diseases. This gene signature correlated with histologic disease severity. Metallothioneins featured prominently among differentially expressed genes, and functional pathway analysis identified specific convergent themes of dysregulation. MetaCore network analyses revealed various novel candidate hub genes (e.g. STAU2). Genes associated with M1-polarized macrophages and reactive astrocytes were strongly enriched in the meta-analysis data. Evaluation of genes enriched in neurons revealed 70 down-regulated genes, over half not previously associated with neurodegeneration. Comparison with aging brain data (3 patient cohorts, 221 samples) revealed 53 of these to be unique to neurodegenerative disease, many of which are strong candidates to be important in neuropathogenesis (e.g. NDN, NAP1L2). ENCODE ChIP-seq analysis predicted common upstream transcriptional regulators not associated with normal aging (REST, RBBP5, SIN3A, SP2, YY1, ZNF143, IKZF1). Finally, we removed genes common to neurodegeneration from disease-specific gene signatures, revealing uniquely robust immune response and JAK-STAT signaling in amyotrophic lateral sclerosis. Our results implicate pervasive bioenergetic deficits, M1-type microglial activation and gliosis as unifying themes of neurodegeneration, and identify numerous novel genes associated with neurodegenerative processes.

Isolation of enriched glial populations from post-mortem human CNS material by immuno-laser capture microdissection

Isolating individual populations of cells from post-mortem (PM) central nervous system (CNS) tissue for transcriptomic analysis will provide important insights into the pathogenesis of neurodegenerative diseases. To date, research on individual CNS cell populations has been hindered by the availability of suitable PM material, unreliable sample preparation and difficulties obtaining individual cell populations. In this paper we report how rapid immunohistochemistry combined with laser capture microdissection (immuno-LCM) enables the isolation of specific cell populations from PM CNS tissue, thereby enabling the RNA profile of these individual cell types to be investigated. Specifically, we detail methods for isolating enriched glial populations (astrocytes, oligodendrocytes and microglia) and confirm this cell enrichment by polymerase chain reaction (PCR). In addition, the study details the numbers of each glial population required to obtain 50ng RNA, a suitable amount of starting material required to carry out microarray analysis that potentially may identify alterations of cell-specific genes and pathways associated with a range of neurodegenerative disorders.

ABC Transporter (P-gp/ABCB1, MRP1/ABCC1, BCRP/ABCG2) Expression in the Developing Human CNS

P-glycoprotein (P-gp/ABCB1), multidrug resistance associated protein 1 (MRP1/ABCC1), and breast cancer resistance protein (BCRP/ABCG2) are plasma membrane efflux pumps that limit the intracellular uptake and retention of numerous lipophilic, amphipathic xeno- and endobiotics. Little is known about the neonatal and developmental expression of P-gp/ABCB1, MRP1/ABCC1, and BCRP/ABCG2 in the human central nervous system (CNS), therefore post-mortem CNS tissue from infants born at 22 (0/7)-42 (0/7) weeks of gestation and adults was immunostained to determine their ontogeny and cellular localization. P-gp/ABCB1 immunostaining was observed in microvessel endothelial cells as early as 22 (0/7) weeks, increasing in prevalence and intensity with maturation, and later in gestation in large pyramidal neurons. MRP1/ABCC1 immunostaining was prominent early in the choroid plexus and ventricular ependyma, and noted later in large pyramidal neurons. BCRP/ABCG2 expression was limited to microvessel endothelial cells. P-gp/ABCB1, MRP1/ABCC1 and BCRP/ABCG2 in adult brain matched term newborn CNS but with more intense immunostaining. We conclude that P-gp/ABCB1, MRP1/ABCC1, and BCRP/ABCG2 are expressed in a developmental, cell specific, fashion in the human CNS. The complementary pattern of P-gp/ABCB1 and BCRP/ABCG2 at the blood-brain with MRP1/ABCC1 at the blood-CSF barriers may limit CNS uptake and retention of drugs and toxins in neonates.

The Werner Syndrome Helicase Is a Cofactor for HIV-1 Long Terminal Repeat Transactivation and Retroviral Replication

The Werner syndrome helicase (WRN) participates in DNA replication, double strand break repair, telomere maintenance, and p53 activation. Mutations of wrn cause Werner syndrome (WS), an autosomal recessive premature aging disorder associated with cancer predisposition, atherosclerosis, and other aging related symptoms. Here, we report that WRN is a novel cofactor for HIV-1 replication. Immortalized human WRN(-/-) WS fibroblasts, lacking a functional wrn gene, are impaired for basal and Tat-activated HIV-1 transcription. Overexpression of wild-type WRN transactivates the HIV-1 long terminal repeat (LTR) in the absence of Tat, and WRN cooperates with Tat to promote high-level LTR transactivation. Ectopic WRN induces HIV-1 p24(Gag) production and retroviral replication in HIV-1-infected H9(HIV-1IIIB) lymphocytes. A dominant-negative helicase-minus mutant, WRN(K577M), inhibits LTR transactivation and HIV-1 replication. Inhibition of endogenous WRN, through co-expression of WRN(K577M), diminishes recruitment of p300/CREB-binding protein-associated factor (PCAF) and positive transcription elongation factor b (P-TEFb) to Tat/transactivation response-RNA complexes, and immortalized WRN(-/-) WS fibroblasts exhibit comparable defects in recruitment of PCAF and P-TEFb to the HIV-1 LTR. Our results demonstrate that WRN is a novel cellular cofactor for HIV-1 replication and suggest that the WRN helicase participates in the recruitment of PCAF/P-TEFb-containing transcription complexes. WRN may be a plausible target for antiretroviral therapy.

Detection of HHV-6B in post-mortem central nervous system tissue of a post-bone marrow transplant recipient: a multi-virus array analysis

Background HHV-6 has been implicated in a number of neurological disorders. Recent evidence has suggested high incidence of HHV-6 infection in patients (46%) undergoing allogeneic bone marrow transplant (BMT). Objective To investigate whether HHV-6 plays a role in the development of fatal encephalopathy in an allogeneic post-BMT patient using an unbiased approach. Results Detection of HHV-6 viral DNA sequence and RNA expression were demonstrated in fresh frozen post-mortem autopsy material derived from the insular cortex using a multi-virus array platform. In addition, PCR analysis by real-time quantitative TaqMan demonstrated high viral burden in multiple brain regions tested. Sequencing analysis of PCR product confirmed the virus to be HHV-6 variant B. Conclusions Active infection as demonstrated by expression of viral RNA and high viral load in the CNS suggest a possible pathogenic role of HHV-6 in development neurologic complications post-BMT.

HIV-1 Tat Interactions with p300 and PCAF Transcriptional Coactivators Inhibit Histone Acetylation and Neurotrophin Signaling through CREB

The human immunodeficiency virus type-1 (HIV-1) infects microglia, macrophages, and astrocytes in the central nervous system (CNS) and may cause severe neurological diseases, such as AIDS-related dementias or progressive encephalopathies, as a result of CNS inflammation and neurotrophin signaling defects associated with expression of viral antigens and HIV-1 replication in the brain. The HIV Tat protein can be endocytosed by surrounding uninfected cells; interacts with transcriptional coactivators/acetyltransferases, p300/CREB-binding protein, and p300/CREB-binding protein-associated factor (PCAF); and induces neuronal apoptosis. Since nerve growth factor (NGF) receptor and brain-derived neurotrophic factor receptor signaling through CREB requires p300 and PCAF histone acetyltransferases, we sought to determine whether HIV-1 Tat coactivator interactions interfere with neurotrophin receptor signaling in neuronal cells. Here, we demonstrate that Tat-coactivator interactions inhibit NGF- and brain-derived neurotrophic factor-responsive CRE trans-activation and neurotrophin protection against apoptosis in PC12 and IMR-32 neuroblastoma cells. Purified recombinant Tat or Tat-derived synthetic peptides, spanning p300- and PCAF-binding sequences, inhibit histone H3/H4 acetylation in vitro. A Tat mutant, TatK28A/K50A, defective for binding p300 and PCAF, neither repressed NGF-responsive CRE transactivation nor inhibited histone acetylation. HIV-1 Tat interacts in PCAF complexes in post-mortem CNS tissues from donor neuro-AIDS patients, as determined by fluorescence resonance energy transfer immunoconfocal microscopy. Importantly, these findings suggest that HIV-1 Tat-coactivator interactions may contribute to neurotrophin signaling impairments and neuronal apoptosis associated with HIV-1 infections of the CNS.

Developmental effects of von Hippel–Lindau gene deficiency

The histogenetic origin and the basis of the distribution of central nervous system (CNS) hemangioblastomas in the von Hippel-Lindau (VHL) tumor suppressor gene syndrome, VHL disease, are unknown. To better understand hemangioblastoma histogenesis, we analyzed postmortem CNS tissues from four patients with well-established diagnosis of VHL disease including development of characteristic tumors and positive family history. Numerous angiomesenchymal tumorlets, which resembled hemangioblastoma, but which also consistently showed distinct histological features, were distributed in the nerve roots, spinal cord, and cerebellum. Genetic analysis consistently showed deletion of the wild-type VHL allele in these tumorlets. Most angiomesenchymal tumorlets were in the dorsal nerve roots; the anterior roots and cerebellum were less frequently affected. Tumorlet distribution was highly consistent in the four cases. In analogy to the wide morphological spectrum of lesions known to exist in VHL kidneys, nerve roots appear to harbor more wide-spread and morphologically heterogeneous changes than previously appreciated. The abundance of tumorlets, associated with highly consistent morphology and topography, suggests a developmental origin of hemangioblastoma. Therefore, in VHL disease, inactivation of the VHL wild-type allele appears necessary, but not sufficient, for the formation of tumor that produces symptoms and neurological disability.

The neurobiology of bipolar disorder: findings using human postmortem central nervous system tissue

Objective: Postmortem brain studies have been undertaken to understand changes in the molecular architecture of the central nervous system (CNS) of subjects with bipolar disorder. These studies, along with a limited number of functional neuroimaging studies, have been reviewed to provide information on the neurobiology underlying the disorder. Method: Findings from the study of postmortem brain tissue and neuroimaging were reviewed if their focus was on the molecular architecture of the human CNS to identify future lines of research required to understand the underlying pathology of bipolar disorder. Results: There is considerable evidence to implicate the serotonergic system of the CNS and abnormalities in signal transduction pathways in the pathology of bipolar disorder. In addition, preliminary findings suggest that changes in the benzodiazepine binding site on the γ aminobutyric acid A receptor may be affected in bipolar disorder. Conclusions: Further systematic studies on the serotonergic systems of the CNS, as well as the interaction between neurotransmitter receptors, G-proteins and signal transduction pathways are required to better understand the pathology of bipolar disorder. In addition, findings on the serotonin transporter indicate that changes in presynaptic function may be a critical component of the pathology of bipolar disorder.

Evidence for persistent enterovirus infection of the central nervous system in patients with previous paralytic poliomyelitis.

It has been suggested that late onset neurological deterioration after poliomyelitis may be due in some cases to persistent poliovirus infection of the central nervous system. In view of this, we decide to determine whether polioviruses and other enteroviruses can persist in the central nervous system. In a previous study, one of us (M.K.S.) reported serological evidence of persistent poliovirus infection of the central nervous system (CNS) in a proportion of these patients. We have now studied cerebrospinal fluid (CSF) from these patients for the presence of enterovirus RNA sequences using the polymerase chain reaction (PCR). Enteroviral RNA was detected in 3 of 24 patients with a clinical diagnosis of post-polio syndrome, but in none of 36 patients with stable poliomyelitis, and none of 36 patients with other neurological conditions of noninfective origin. All 3 patients in whom viral RNA was detected had high intrathecal levels of poliovirus-specific oligoclonal IgM bands. In a second study we examined formalin-fixed postmortem CNS tissue from 7 patients with a history of paralytic poliomyelitis. Enterovirus RNA was detected in tissue from the spinal cord from 3 patients, but not in the cerebral cortex. We are now conducting a larger prospective, blind study of patients with evidence of late deterioration. Analysis of the first 30 patients studied revealed the presence of enterovirus RNA in CSF of 1 of 4 patients with unexplained late-onset post-polio weakness, 1 of 6 with some evidence of clinical deterioration, but none of 20 without inexplicable signs of post-polio weakness. Enteroviral RNA was also detected in spinal cord from 2 of 3 patients who died from other causes during this study. These studies provide virological evidence that enteroviruses may persist in the CNS of man. Further study is required in order to understand fully the biological and clinical significance of these findings.