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At least 19 recordsLinked to original sources

Mapping the causal chain from genetic risk variants to lipid dysmetabolism in Parkinson's disease.

The molecular pathways linking genetic variants to Parkinson's disease (PD) onset and progression remain incompletely defined; however, risk alleles in multiple genes, including GBA1, strongly implicate lipid metabolism. To systematically identify causal biomarker signatures, we analysed comprehensive metabolome profiles from blood plasma in 149 PD patients and 150 controls, along with complementary genetic, RNA-sequencing and metabolic data from other available clinical and pathologic cohorts. Using colocalization and summary-data-based Mendelian randomization, we tested whether expression and metabolic quantitative trait loci mediate the association between implicated genetic variants and PD risk. We further integrated differential metabolomics and proteomics from blood and brain to reveal pertinent mechanisms. We show that common PD risk variants at the serine palmitoyltransferase small subunit B (SPTSSB) locus, a key regulator of de novo sphingolipid biosynthesis, are associated with increased SPTSSB brain expression and elevated plasma ceramides. Additional analyses strongly support our hypothesis that a common SPTSSB causal variant is responsible for PD risk as well as the expression and metabolic quantitative trait loci. Multiple sphingolipids and fatty acid derivatives were perturbed in PD, and we identified both unique and shared features with the Alzheimer's disease metabolome. A PD acylcarnitine signature was further replicated in human post-mortem brain tissue, when comparing those with or without preclinical Lewy body pathology. Integrated analysis of complementary brain proteomic profiles revealed dysregulation of mitochondrial processes dependent on acylcarnitines, including fatty acid beta-oxidation, the tricarboxylic acid cycle and oxidative phosphorylation. Our results identify promising biomarkers and reveal a causal chain linking genetic variation to altered gene/protein expression, lipid dysmetabolism, and the manifestation of PD.

Humans

Lysine methylation is an endogenous post-translational modifications of tau protein in human brain and a modulator of aggregation propensity.

Tau protein undergoes a broad range of post-translational modifications in the brain, influencing its structure, solubility, and propensity to aggregate. This chapter presents an integrated methodological framework for characterizing tau methylation and evaluating its impact on tau biology. We describe procedures for isolating soluble and filamentous tau from post-mortem human brain tissue while preserving modifications for proteomic analysis. These approaches support precise mapping of methylation sites alongside other co-occurring modifications. To model methylation under controlled conditions, we outline protocols for recombinant tau expression, purification, and chemical reductive methylation, including radiolabeled assays for determining modification stoichiometry. We then detail biophysical assays used to assess how methylation alters tau conformation and aggregation propensity. This methodological framework supports experimentation seeking insight into mechanisms relevant to Alzheimer's disease and related tauopathies.

Humans

Alternative splicing in layer 3 pyramidal neurons differs across regions of the human cortical hierarchy.

The primate neocortex is organized as hierarchical networks of functionally distinct regions. In the dorsal visual stream network, information is conveyed from primary visual (V1) to posterior parietal (PPC) and dorsolateral prefrontal (DLPFC) cortices. This information transfer is mediated primarily by layer 3 pyramidal neurons (L3PNs), which differ across these regions in morphology, excitability, and intracellular Ca2+ regulation. These region-specific L3PN properties may be influenced by alternative splicing (AS) of pre-mRNA, which occurs extensively in the human brain. To explore the potential impact of AS of region-specific L3PN properties, we analyzed RNA-seq data from pools of L3PNs dissected from human V1, PPC, and DLPFC. We found that&#x2009;<6% of genes with regional differences in expression also differed in AS. This finding indicates that the absence of transcriptional differences is insufficient to conclude that a gene does not contribute functional differences between regions. Additionally, there were numerous regional differences in AS, particularly between V1 and DLPFC or PPC L3PNs, which involved genes associated with neuron morphology and Ca2+ regulation; >&#x2009;90% of these AS differences involved functionally relevant sequences (eg phosphorylation sites, etc.). These findings suggest AS contributes to region-specific L3PN properties relevant to the function of the dorsal visual stream.

Humans

Studies of the TSH radioreceptor assay.

We have examined several variables in the reagents and procedures used in the TSH radioreceptor assay, the binding of iodinated TSH to its thyroidal receptor. We found that iodinated bovine TSH (S.A. 30 U/mg) was more effectively bound to receptor than iodinated human TSH (S.A. 7.3 U/mg). Iodination of TSH was the Bolton-Hunter acylation method apparently prevented binding to TSH receptor. Surgically removed human thyroid tissue specifically bound 10.3 +/- 1.0 (mean +/- SEM) of added [125I]TSH, but post-mortem human thyroid bound only 3.9 +/- 0.4% of [125I]TSH (p less than 0.001). Maximal binding of [125I]TSH was found at pH 5.8. Many tissue preparations contained activity, possibly due to proteases, which inactivated TSH, and inclusion of a protease inhibitor, aprotinin, significantly increased specific binding.

Animals

Cloning of human DING: Developmental expression and downregulation by EtOH in-utero.

INTRODUCTION: An estimated 15-20% of women consume alcohol (EtOH) during pregnancy. Women with alcohol use in early pregnancy are likely to have a child with fetal alcohol spectrum disorders (FASD). Recently, we reported neuroprotective effects of human DING (a member of the DING family of phosphatases) against EtOH-mediated toxicity in rats and in human fetal cortical neurons in vitro. Now, we report the sequencing and developmental expression patterns of endogenous DING in human fetal brain. METHODS: DING cDNA was cloned from human U87MG astrocytoma cells with primers specific to the plant DING gene and known prokaryotic DING genes. This cDNA was used to prepare antibodies. The full-length human DING gene p38hu (1095 nucleotide bases) is flanked by the first initiating codon, ATG, and the last, stop codon, TAA. Post-mortem fetal tissues and maternal blood were collected during pregnancy between 8 and 37 weeks' gestation. The developmental, spatial, and temporal expression of DING protein in fetal brain tissue was analyzed by immunohistochemistry. Developmental expression of DING in fetal brain and placenta was quantified by qWestern blots. DING promoter expression was assayed by ddPCR. Statistical analysis included ANOVA. RESULTS: Sequencing revealed different-sized genomic DNA clones. The anti-DING antibody detected proteins ranging in size from 35 to 40 kDa, and high molecular weight precursor protein in fetal brain and placenta. DING protein was present in fetal brain at early stages and its level was increased at later gestational ages. The DING promoter was expressed in fetal brain, neurospheres, and fetal brain-derived exosomes. DING levels were reduced in samples exposed to maternally consumed alcohol. CONCLUSIONS: Because DING is neuroprotective, its reduced expression in fetuses exposed to alcohol may suggest a mechanism that contributes to the pathogenesis of FASD, which could lead to the development of therapeutic tools aimed at preventing, ameliorating or reversing this prevalent group of syndromes that are implicated in as many as 5% of births world-wide.

DING gene cloning

Changes of some putative neurotransmitters in human cerebral infarction.

Dopamine (DA), serotonin (5-HT), tryptophan (TRP), 5-hydroxyindole acetic acid (5-HIAA), and GABA were assayed spectrofluorometrically in various regions of 16 human post-mortem brains with acute and old cerebral infarction. In both recent and older strokes a total depletion of DA and 5-HT in the necrotic tissue was associated with mild reduction of these compounds in remote non-ischemic areas of the injured, and less of the contralateral cerebral hemispheres. 5-HIAA was significantly reduced in acute ischemic necrosis, while the perifocal edema zone showed considerable accumulation of both 5-HT and 5-HIAA. Marked elevation of the 5-HT precursor TRP and of GABA was present in both the necrotic center and perifocal edema of acute infarcts, which also showed a mild reduction of total proteins. The degradation zone surrounding old infarcts showed a mild decrease of both 5-HT and 5-HIAA with normal TRP levels, indicating normalization of the previously increased 5-HT metabolism and turnover after decrease of acute cerebral edema. These data which confirm previous studies in experimental cerebral ischemia and stroke indicate that disorders in the metabolism of brain monoamines and other putative neurotransmitters contribute to the development of postischemic brain damage and the complicating cerebral edema. They are also in keeping with the concept that unilateral focal ischemia produces bilateral effects on brain monoamines.

Aged

Characterization of the brain virome in human immunodeficiency virus infection and substance use disorder.

Viruses can infect the brain in individuals with and without HIV-infection: however, the brain virome is poorly characterized. Metabolic alterations have been identified which predispose people to substance use disorder (SUD), but whether these could be triggered by viral infection of the brain is unknown. We used a target-enrichment, deep sequencing platform and bioinformatic pipeline named "ViroFind", for the unbiased characterization of DNA and RNA viruses in brain samples obtained from the National Neuro-AIDS Tissue Consortium. We analyzed fresh frozen post-mortem prefrontal cortex from 72 individuals without known viral infection of the brain, including 16 HIV+/SUD+, 20 HIV+/SUD-, 16 HIV-/SUD+, and 20 HIV-/SUD-. The average age was 52.3 y and 62.5% were males. We identified sequences from 26 viruses belonging to 11 viral taxa. These included viruses with and without known pathogenic potential or tropism to the nervous system, with sequence coverage ranging from 0.03 to 99.73% of the viral genomes. In SUD+ people, HIV-infection was associated with a higher total number of viruses, and HIV+/SUD+ compared to HIV-/SUD+ individuals had an increased frequency of Adenovirus (68.8 vs 0%; p<0.001) and Epstein-Barr virus (EBV) (43.8 vs 6.3%; p=0.037) as well as an increase in Torque Teno virus (TTV) burden. Conversely, in HIV+ people, SUD was associated with an increase in frequency of Hepatitis C virus, (25 in HIV+/SUD+ vs 0% in HIV+/SUD-; p=0.031). Finally, HIV+/SUD- compared to HIV-/SUD- individuals had an increased frequency of EBV (50 vs 0%; p<0.001) and an increase in TTV viral burden, but a decreased Adenovirus viral burden. These data demonstrate an unexpectedly high variety in the human brain virome, identifying targets for future research into the impact of these taxa on the central nervous system. ViroFind could become a valuable tool for monitoring viral dynamics in various compartments, monitoring outbreaks, and informing vaccine development.

Male

Targeting DNA mismatch repair in Huntington's disease.

Somatic expansion of the HTT CAG repeat is a key feature of Huntington's disease (HD) pathogenesis. Mismatch repair (MMR) enzymes drive this process through erroneous DNA repair, with variants in MMR genes modifying the onset and progression of disease features. Cell-type-specific CAG repeat sizing recently confirmed that elevated somatic expansion underlies the selective vulnerability of HD medium spiny neurons, with expansion beyond certain CAG thresholds associated with distinct stages of cellular pathogenesis. In this review, we synthesise insights from post-mortem brain tissue, cell systems, and mouse models, detailing key CAG repeat-length-dependent changes. In addition, we critically evaluate the MMR proteins MSH3, MLH3, and PMS1 as therapeutic targets for slowing somatic expansion and outline key safety considerations for emerging MMR-modulating approaches.

Huntington Disease

Pneumococcal antigen in pneumonia. A post-mortem study with the histological and bacteriological findings.

Pneumococcal capsular antigens can be detected in lung tissue by counter-current immunoelectrophoresis even when, following antibiotics, post-mortem bacterilogy suggests that Escherichia coli has replaced pneumococci. The results suggest that antipneumococcal therapy would benefit at least 55% of patients critically ill with lung infection and that the potentially toxic drugs directed at coliform bacteria may be unnecessary.

Aged

Elevated intron retention implicates neuroinflammation in brains of individuals with alcohol use disorder.

Intron retention, a form of alternative RNA splicing, can occur as part of normal gene regulation or result from disruption of the splicing machinery. Retained introns can potentially form double-stranded RNA, activating innate immune sensors and inflammation. This mechanism has been implicated in cancer but has not been studied in neuropsychiatric diseases like alcohol use disorder. We systematically analysed transcriptome-wide intron retention events in post-mortem brain tissue from 142 individuals (66 with alcohol use disorder and 76 controls), encompassing 320 region-specific samples from the superior frontal cortex, nucleus accumbens, central nucleus and basolateral amygdala. Analyses were adjusted for demographic, technical and biological covariates. Validation was performed in alcohol-preferring (P) rats using long-read sequencing. In complementary experiments, immunofluorescent staining was used to detect double-stranded RNA in rat brain tissue, while single-cell RNA-sequencing was performed to test activation of double-stranded RNA-sensing pathways in human brains. Brains from individuals with alcohol use disorder showed significantly higher total intron retention compared with controls, independent of age, with females showing greater increases than males. A total of 368 introns were positively associated with alcohol use disorder, and these introns were significantly longer and had weaker splice acceptor sites compared with non-associated introns. Genes harbouring these intron retention events were enriched in Purkinje neurons, visual cortex neurons and oligodendrocytes. Computational predictions indicated these long introns could form duplex RNA structures. Increased double-stranded RNA was confirmed experimentally in multiple brain regions of alcohol-consuming rats, where it co-localized primarily with neuronal nuclei and dendrites. In individuals with alcohol use disorder, we found that multiple pathways including double-stranded RNA responses, neuroinflammation, interferon and NF-&#x3ba;B signalling, adaptive immunity and apoptosis were activated. In addition, NeuN-positive neuronal counts significantly decreased in both the prefrontal and visual cortices. Furthermore, single-cell analysis demonstrated upregulation of TICAM1, the target of double-stranded RNA sensor TLR3, in oligodendrocytes, as well as widespread activation of downstream inflammatory pathways across glial and neuronal cell types. These findings provide the first evidence that chronic alcohol consumption promotes an overall increase of intron retention in the brain and is associated with the presence of double-stranded RNA. Furthermore, the double-stranded RNA may contribute to neuronal loss and brain pathology by activating a neuroinflammatory response.

alcohol use disorder

A benign deficiency of typeB beta-galactosidase in human liver.

The type A or 'acid' and type B or 'neutral' beta-galactosidase activities have been measured in post-mortem liver samples from individuals dying of non-genetic diseases and patients dying of ganglioside storage disease other than GM1 gangliosidosis. The type A activities fell within the established normal range in all samples. The type B activities showed a biomodal distribution suggesting the occurrence of two distinct populations of human individuals. The greater proportion had activities within the range 11.67 pkat/mg of protein (+/- 3.33, S.D.), while others had lower activities in the range 0.48 pkat/mg of protein (+/- 0.38, S.D.). No clinical symptoms were associated with the much lower type B beta-galactosidase activities and it appears that this beta-galactosidase deficiency could be found in the original tissues. Methods of screening for type B beta-galactosidase deficiency are described and the significance of this enzyme deficiency is discussed.

Chromatography, DEAE-Cellulose

Single-cell analysis of dup15q syndrome reveals developmental and postnatal molecular changes in autism.

Duplication 15q (dup15q) syndrome is a leading genetic cause of autism spectrum disorder, offering a key model for studying autism-related mechanisms. Using single-cell and single-nucleus RNA sequencing of cortical organoids from dup15q patient-derived iPSCs and post-mortem brain samples, we identify increased glycolysis, disrupted layer-specific marker expression, and aberrant morphology in deep-layer neurons during fetal-stage organoid development. In adolescent-adult postmortem brains, upper-layer neurons exhibit heightened transcriptional burden related to synaptic signaling, a pattern shared with idiopathic autism. Using spatial transcriptomics, we confirm these cell-type-specific disruptions in brain tissue. By gene co-expression network analysis, we reveal disease-associated modules that are well preserved between postmortem and organoid samples, suggesting metabolic dysregulation that may lead to altered neuron projection, synaptic dysfunction, and neuron hyperexcitability in dup15q syndrome.

Humans

Proteomic profiling of bone for the estimation of post-mortem interval and post-mortem submersion interval: a systematic review.

Accurate estimation of the Post-Mortem Interval (PMI) and Post-Mortem Submersion Interval (PMSI) remains a persistent challenge in forensic science, especially when traditional morphological and entomological methods fail due to advanced decomposition or in aquatic environments. Proteomic profiling of bone tissues has recently emerged as a promising approach, leveraging the predictable degradation patterns of bone proteins to estimate time since death more reliably. This systematic review, conducted in accordance with PRISMA guidelines, analyzed 24 peer-reviewed studies focusing on the application of proteomic techniques to bone tissue for PMI and PMSI estimation. The included studies were evaluated based on sample type, analytical techniques used, identified biomarkers, environmental conditions assessed, and the overall reliability and reproducibility of the findings. The review found that specific bone proteins, particularly collagen, osteocalcin, fetuin-A, etc. exhibited consistent degradation patterns that correlated strongly with elapsed post-mortem time. Cortical bone was identified as a more stable and informative matrix compared to trabecular bone. Mass spectrometry, especially LC-MS/MS, emerged as the predominant analytical technique due to its high sensitivity and accuracy in detecting low-abundance proteins over extended PMIs and PMSIs. However, protein degradation rates were significantly influenced by environmental variables such as temperature, humidity, soil pH, and microbial activity. This review also emphasizes the transformative role of bone proteomics in advancing forensic science while identifying key gaps that must be addressed to achieve global standardization and practical implementation in diverse forensic contexts. The integration of proteomics with other emerging technologies, such as machine learning algorithms and computational modeling, may further enhance the precision of PMI and PMSI estimation in future applications.

Postmortem Changes

Neurotransmitter-related enzymes and indices of hypoxia in senile dementia and other abiotrophies.

Fifty-six brains from middle-aged and elderly normal as well as demented subjects and patients with provisional clinical diagnosis of other neurological and psychiatric diseases were assessed histologically. On this basis the specimens were classified into 14 diagnostic groups. A survey of potential indices of specific neurons has been carried out on these brains in which neurotransmitter-related enzymes, gamma-GTP (a potential index of capillaries) and specific proteins have been determined in up to 20 brain regions. In addition, the agonal state has been tentatively assessed by examining the post-mortem states of the circulatory and respiratory systems. CAT and gamma-GTP activities and the concentration of a soluble neuronal-type protein (neuronin S-5) were found to be relatively unaffected by the agonal state. When cases of senile dementia were compared to controls (matched with respect to the cause of death) the activity of CAT (the potential index of cholinergic neurons) appears to be reduced in the cerebral cortex. This is a preliminary finding, although a correlation was indicated between CAT activity and 'senile' morphological changes, the activity was markedly reduced in only 3 brains. However, despite inconsistencies in the literature (Karczmar, 1975) at least one pharmacological study on humans appears to show that the cholinergic system may be involved in age-related memory degeneration (Drachman and Leavitt, 1974). Cholinergic neurons may be abnormal in the other abiotrophies examined (Huntington's chorea, motor neuron disease and mixed vascular and senile dementia). gamma-GTP and neuronin S-5 (identical in most respects to the soluble acidic neuronal protein 14-3-2 of antigen alpha) were not reduced in senile dementia. The activities of brain decarboxylase (GAD and AAD) and the concentration of another soluble acidic brain protein (neuronin S-6) appear to be affected by the agonal state. This is remarkable because GAD and, in particular, neuronin S6, are relatively unaffected by post-mortem autolysis. As judged by the state of the extraneural systems which regulated the blood and oxygen supply to the brain it appears that terminal 'cerebral hypoxia' is responsible for the depletion of these brain constituents. This effect appears to be particularly marked in deep grey matter. In non-demented patients that die of bronchopneumonia, the areas of the cortex which are depleted in neuronin S-6 are consistent with the pattern of the 'selective vulnerability' of the cortex to hypoxia, suggesting that the terminal state can also affect the neocortex. If so, then this is particularly relevant to studies on senile dementia, for the effect of the terminal bronchopneumonia that so often occurs in these patients (and in patients with other abiotrophies) may be exacerbated by a terminal reduction in cerebral blood flow...

Adult

The neurochemistry of Parkinson's disease: effect of L-dopa therapy.

Post-mortem brain material from control and Parkinson's disease patients was examined to elucidate further the neurochemistry of this disease and to determine the mechanism of action of L-dopa as a therapeutic agent. The activities of L-aromatic amino acid decarboxylase (dopa D), tyrosine hydroxylase, monoamine oxidase and catechol-O-methyl transferase were examined; in addition the tissue levels of dopa, 3-O-methyldopa, dopamine (DA) and homovanillic acid (HVA) were determined. In the non-dopa-treated Parkinsonian patients, the greatest decreases were detected for striatal DA and dopa D, with homovanillic acid and tyrosine hydroxylase levels showing a lesser change. The activities of monoamine oxidase and catechol-O-methyl transferase in the striatal nuclei were not different from the controls. The putamen was consistently the most severely affected region. Dopa and 3-O-methyldopa were detectable in all brain areas only in those patients treated with L-dopa shortly before death. The mean concentrations of DA in the striatum of these patients were 1) 9 to 15 times higher than those in non-dopa-treated patients, 2) related to the time before death of the last dose of L-dopa and 3) greater in the striatum of patients clinically classified as "good responders" as compared to "poor responders." Although L-dopa therapy increased homovanillic acid levels in all brain areas, a preferential increase was observed in the striatum. It was concluded that L-dopa's principal therapeutic effects in Parkinson's disease are consistent with its transformation to DA in the striatum.

Aged

Distinct spatial transcriptomic patterns of substantia Nigra in Parkinson disease and Parkinsonian subtype of multiple system atrophy.

To investigate transcriptomic signatures of Parkinson's disease (PD) and the Parkinsonian subtype of Multiple System Atrophy (MSA-P) in substantia nigra pars compacta (SNpc), we conducted transcriptome analysis using in-situ hybridization on paraffin-embedded SNpc tissues from post-mortem brains. The study included 2 MSA-P patients, 2 PD patients, and 2 healthy controls (HC), with 12 regions of interest (ROIs) selected from the dorsal to ventral and medial to lateral aspects of the SNpc. A total of 72 ROIs from 6 participants were analyzed, and differentially expressed genes (DEGs) were identified by comparing MSA-P, PD and HC groups. The MSA-P group showed 88 upregulated DEGs and 326 downregulated DEGs (adjusted &#x1d45d;<0.05) compared to HC. The downregulated DEGs were significantly enriched in pathways related to ribosomal translation, immune processes, mitochondrial function, and autophagy. Notably, the dorsomedial quadrant was uniquely linked to antigen presentation, while other quadrants showed downregulation of protein synthesis. The PD group exhibited 165 upregulated DEGs and 350 downregulated DEGs (adjusted &#x1d45d;<0.05) compared to HC, with downregulated DEGs associated with ribosomal translation, mitochondrial function, and the ubiquitin-proteasome system. In both MSA-P and PD, the upregulated DEGs were not associated with any pathways or biological process in gene enrichment analysis. In network propagation analysis, amyloid precursor protein was the most significant network hub among DEGs in both MSA-P and PD. Comparing the transcriptomic signatures of SNpc between MSA-P and PD, we found immune/inflammation, mitochondrial function and neural signaling related genes were significantly downregulated in MSA-P compared to PD. Overall, the transcriptomic signature of the SNpc in MSA-P and PD revealed overlapping but distinct features, including alterations in protein synthesis, immune processes, mitochondrial function, and protein degradation systems. Future studies with larger cohorts and functional validation are needed to further elucidate these findings.

Humans