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Lipid peroxidation is a major outcome of free radical-mediated injury to brain, where it directly damages membranes and generates a number of oxidized products. Some of the chemically and metabolically stable oxidation products are useful in vivo biomarkers of lipid peroxidation. These include the isoprostanes (IsoPs) and isofurans (IsoFs), derived from arachidonic acid (AA), and neuroprostanes (NeuroPs), derived from docosahexaenoic acid (DHA). We have shown increased levels of IsoPs, NeuroPs, and IsoFs in diseased regions of brain from patients who died from advanced Alzheimer's disease (AD) or Parkinson's disease (PD). Increased cerebrospinal fluid (CSF) levels of IsoPs are present in patients with AD or Huntington's disease (HD) early in the course of their illness, and CSF IsoPs may improve the laboratory diagnostic accuracy for AD. In contrast, quantification of IsoPs in plasma and urine of AD patients has yielded inconsistent results. These results indicate that brain lipid peroxidation is a potential therapeutic target early in the course of AD and HD, that CSF IsoPs may aid in the assessment of anti-oxidant experimental therapeutics and laboratory diagnosis of AD.

We report the first longitudinal analysis of cerebrospinal fluid (CSF) F2-isoprostanes (IsoPs), quantitative in vivo biomarkers of lipid peroxidation, in patients with mild Alzheimer's disease (AD). CSF F2-IsoPs (i) were significantly increased in patients followed over one year, (ii) correlated with some clinical indices of dementia following correction for variation in ventricular enlargement, and (iii) were significantly lower in patients who used both alpha-tocopherol and vitamin C.

Activation of glial innate immunity is widely proposed to contribute to a number of degenerative and destructive diseases of brain. However, the precise role of activated innate immunity has been difficult to define in vivo because of multiple simultaneous pathogenic processes and responses to injury that confound interpretation of results from complex models of disease. Here, we used the model of intracerebroventricular (ICV) injection of lipopolysaccharide (LPS) to test the hypothesis that directly activated glial innate immunity leads to neurodegeneration in cerebrum and to establish the molecular determinants of and neuroprotectants from such innate immunity-mediated neuronal damage. Our results showed that ICV LPS induced delayed, reversible oxidative damage to cerebral neuronal membranes as measured by F4-neuroprostanes that was coincident with degeneration of the hippocampal pyramidal neuron dendritic system, but not neuron death, in adult mice. Both neuronal oxidative damage and dendritic degeneration were NF-kappaB and iNOS dependent and were completely suppressed by ibuprofen and alpha-tocopherol, but not naproxen or gamma-tocopherol. These results prove that activation of glial innate immunity can lead to neurodegeneration independent of other pathologic processes, closely associate oxidative damage to neuronal membranes with degeneration of the dendritic system, and provide a possible explanation for the varying efficacy of neuroprotectants that have been suggested in observational studies of dementia.

Carbonyl stress from products of lipid peroxidation, such as 4-hydroxynonenal (HNE), and products of sugars in diabetes mellitus, such as methylglyoxal (MG) and glyoxal (G), may contribute to neurodegeneration in Alzheimer's disease (AD). We tested the hypothesis that these carbonyls alter the proposed central pathogenic mechanism of AD, intracellular amyloid-beta (A beta)-mediated cytotoxicity, using a human neuroblastoma cell line that conditionally expresses carboxy-terminal fragments (CTFs) of the amyloid precursor protein. HNE was a potent cytotoxin, whereas G was mildly cytotoxic; cytotoxicity from each was independent of A beta/CTF expression and not altered by alpha-tocopherol. In contrast, MG cytotoxicity was enhanced by the induced expression of A beta/CTFs and suppressed by alpha-tocopherol. alpha-tocopherol cytoprotection was accompanied by decreased A beta/CTF aggregation. G also promoted beta/CTF aggregation but by mechanisms unaffected by alpha-tocopherol treatment. Our findings showed that A beta/CTF aggregation and cytotoxicity may be profoundly altered by aldehydes associated with diabetes and that in the case of MG, this process is suppressed by alpha-tocopherol. Moreover, our results suggest that while intracellular aggregation of A beta/CTFs may be necessary for the development of toxicity attributable to their expression in this model, the presence of high-molecular weight aggregated A beta/CTFs does not invariably lead to cytotoxicity.

Lipid peroxidation has been implicated in the pathogenesis of a number of diseases, including neurodegenerative disorders. Evidence that antioxidants can affect the clinical course of neurodegenerative diseases is limited. In the present study, we examined the ability of five common antioxidants or antioxidant combinations, alpha-tocopherol, gamma-tocopherol, ascorbic acid, GSH ethyl ester, and a combination of ascorbate and alpha-tocopherol, to modulate lipid peroxidation in peroxidizing rat cerebral synaptosomes, a well-characterized model of oxidant injury. In these studies, we quantified isoprostanes (IsoPs) derived from arachidonic acid as an index of whole tissue oxidation and neuroprostanes (NeuroPs) formed from docosahexaenoic acid as a marker of selective neuronal peroxidation. We report that these various antioxidants displayed markedly different capacities to inhibit IsoP and NeuroP formation with the most potent effects on IsoPs observed for ascorbate, GSH ethyl ester, and the alpha-tocopherol-ascorbate combination. alpha-Tocopherol was slightly less potent and gamma-tocopherol significantly less effective. The concentration-response relationships were significantly different for NeuroP formation with the antioxidants being significantly less potent than for IsoP generation. In particular, alpha-tocopherol did not inhibit NeuroP formation at concentrations up to 100 microM. We also determined that tocopherols, in particular alpha-tocopherol, act in vitro as reducing agents to convert IsoP and NeuroP endoperoxides to reduced F-ring compounds, a finding we have observed previously in vivo in brain. These studies are of importance because they have further defined the role of antioxidants to modulate the formation of lipid peroxidation products in peroxidizing brain tissue. In addition, they suggest that alpha-tocopherol may not be a particularly effective agent to inhibit oxidant stress in the terminal compartment of neurons in the central nervous system.

4-Hydroxy-2-nonenal (HNE), a potent toxin formed in the brain from oxidation of polyunsaturated fatty acids, is increased in Alzheimer disease (AD), where it is a proposed effector of amyloid beta peptide-mediated neurotoxicity. Detoxification of HNE via the mercapturic acid pathway (MAP) is the primary means by which other organs, such as liver, limit its toxic effects. Here we examined the distribution and activity of MAP detoxification for HNE in cerebrum. Our results showed that rat cerebral cortex and especially synaptosomes were less well equipped to detoxify HNE via the MAP than liver. Glutathione transferases (GSTs) catalyze the committed step in the MAP; GST-mu and GST-pi, but not OST-alpha, were detected in neurons and astrocytes in cerebrum from AD patients and controls. MAP activity in frontal cortex of AD patients was modestly but significantly increased compared to controls. These data suggest that lipid peroxidation may present a greater toxic burden to cerebrum than to other organs, and that a component of response to injury in late stage AD is a slight increase in MAP activity.

Dithiocarbamate (DTC)-based pesticides have been implicated in Parkinson's disease (PD) through epidemiological links to increased risk of PD, clinical reports of parkinsonism following occupational exposure to the DTC-based pesticide maneb, and experimental studies showing dopaminergic neurodegeneration with combined exposure of rats to maneb and paraquat. We hypothesize that the manganese-ethylene-bis-dithiocarbamate (MnEBDC) complex in maneb may produce oxidative stress by catalyzing catechol oxidation. We tested this hypothesis by performing a structure-function analysis of metal-EBDC and metal-diethyldithiocarbamate (DEDC) complexes of Mn2+, Zn2+, and Cu2+ to catalyze oxidation of N-acetyldopamine (NA-DA) and 3,4-dihydroxyphenylacetic acid (DP) in the presence and absence of N-acetylcysteine (NAC), a model of glutathione. Both Mn-DTCs retained the capacity of the parent ion to catalyze one-electron oxidation of NA-DA, but lost the ability to catalyze DP oxidation. Strikingly, while Zn2+ did not catalyze catechol oxidation, both Zn-DTCs catalyzed one-electron oxidation of NA-DA but not DP. While Cu2+ catalyzed oxidation of both catechols, Cu-DTCs were inert. Similar results were obtained with MnEBDC and dopamine or norepinephrine; however, zinc-ethylene-bis-dithiocarbamate was less efficient at catalyzing oxidation of these catechols. Our results point to the potential for manganese- and zinc-containing EBDC pesticides to promote oxidative stress in catecholaminergic regions of the brain.

Dopamine (DA) oxidation is proposed to be a significant contributor to some forms of neurodegeneration, although the mechanisms are not fully resolved. Recent results from in vitro and in vivo models have suggested that some products of oxidized DA metabolized along the mercapturic acid pathway (MAP) may contribute to dopaminergic neurodegeneration. Here we review recent findings on the localization of MAP enzymes in human brain, as well as the concentration and neurotoxicity of their DA thioether products.

To better understand the pathogenesis of herpes simplex virus type 1 (HSV-1) infections of the nervous system, concentrations of F(4)-neuroprostanes (F(4)-NP) and F(2)-isoprostanes (F(2)-IP) in the murine brain were determined following intracerebral inoculation of HSV-1 or normal saline. F(4)-NP are highly selective, quantitative markers of neuronal oxidative damage, while F(2)-IP are markers of oxidative damage to brain tissue not limited to a certain cell type. In contrast to saline-treated control animals, HSV-1-infected animals developed encephalitic symptoms associated with severe inflammation, widespread HSV-1 protein expression, and significantly elevated F(4)-NP and F(2)-IP levels in the brain. Survivors of acute HSV-1 infection showed no encephalitic symptoms 2 to 3 weeks following virus inoculation. Brain tissue derived from mice euthanized 2 month after virus inoculation demonstrated expression of HSV-1 latency-associated transcripts without detectable HSV-1 protein expression. However, brain tissue from these animals showed focal chronic inflammation, moderately elevated F(2)-IP levels, and normal levels of F(4)-NP. These observations provide novel biochemical evidence that oxidant tissue injury is a mechanism underlying neuronal damage during acute HSV-1 encephalitis and suggest that oxidative damage to tissue may continue in the mammalian brain until at least several weeks after recovery from the symptomatic phase of HSV-1 infection.

Oxidative stress can impair proteasome function, both of which are features of neurodegenerative diseases. Inhibition of proteasome function leads to protein accumulation and cell death. We discovered recently the formation of highly reactive g-ketoaldehydes, isoketals (IsoKs), and neuroketals (NeuroKs) as products of the isoprostane and neuroprostane pathways of free radical-induced lipid peroxidation that are analogous to cyclooxygenase-derived levuglandins (LGs). Because aldehydes that are much less reactive than IsoKs have been shown to inhibit proteasome function, we explored the ability of the proteasome to degrade IsoK-adducted proteins/peptides and the effect of IsoK and IsoK-adducted proteins/peptides on proteasome function. Adduction of IsoK to model proteasome substrates significantly reduced their rate of degradation by the 20S proteasome. The ability of IsoK to inhibit proteasome function directly was observed only at very high concentrations. However, at much lower concentrations, an IsoK-adducted protein (ovalbumin) and peptide (Ab1-40) significantly inhibited chymotrypsin-like activity of the 20S proteasome. Moreover, incubation of IsoK with P19 neuroglial cultures dose-dependently inhibited proteasome activity (IC50 = 330 nM) and induced cell death (LC50 = 670 nM). These findings suggest that IsoKs/NeuroKs/LGs can inhibit proteasome activity and, if overproduced, may have relevance to the pathogenesis of neurodegenerative diseases.

Epidemiological and clinical trial data indicate that at least some non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of developing Alzheimer's disease (AD). Advancing age is the most robust risk factor for AD. If NSAIDs mitigate the initiation of AD by affecting processes of aging, and if the target of NSAIDs are cyclooxygenases (COX), then COX activity would be hypothesized to increase with advancing age in brain regions affected by AD. We tested this hypothesis in mouse cerebrum by measuring two outcomes of increased COX activity, prostaglandin (PG) levels and markers of oxidative damage. Our results showed that frontal cortical PGE(2) and 6-keto-PGF(1alpha) levels were significantly increased at 14 months compared to 2 months, but that frontal cortical levels of these PGs at 26 months returned to levels observed at 2 months of age. At all ages, 2-week treatment with indomethacin (14 microg/ml drinking water, or approximately 2.2 mg/kg per day) equally suppressed frontal cortical levels of both PGs. In contrast, basal levels of oxidative damage to cerebral cortex did not increase in mice aged up to 26 months, and indomethacin treatment did not significantly alter basal levels of oxidative damage as assayed by F(2)-isoprostanes or protein carbonyls. These results suggest that indomethacin may influence the initiation of AD by reducing cerebral PG elevation that may occur in middle age, but that it is unlikely to have a direct effect on levels of oxidative damage.

Recent studies of cerebrospinal fluid (CSF) have shown increased oxidation of CSF lipoproteins in Alzheimer's disease (AD) patients, and neurotoxicity from oxidized CSF lipoproteins in culture. Since inheritance of different alleles of the apolipoprotein (apo) E gene is a risk factor for AD and apoE is the major lipoprotein trafficking molecule in brain, we hypothesized that apoE may modify the pathogenesis of AD by directing the delivery of oxidized CSF lipoproteins to neurons. To test this hypothesis, we adapted a method previously used with isolated plasma lipoproteins to specifically label lipid particles in situ in native CSF and quantified their delivery to human SK-N-BE(2)C neuroblastoma cells. CSF lipoproteins were delivered to neuronal cells largely through apoE-dependent processes. Importantly, CSF lipoproteins from AD patients were delivered more efficiently than CSF lipoproteins from age-matched controls; this effect was not associated with apoE genotype or degree of CSF lipoprotein oxidation but was associated with apoE monomer concentration that tended to be lower in AD patients. The inverse relationship between apoE monomer concentration and CSF lipoprotein delivery was duplicated in SK-N-BE(2)C cells, but not human astrocytoma cells, using artificial lipid particles and purified human apoE. These results suggest that lipoproteins in CSF from AD patients are delivered more efficiently to neurons than are CSF lipoproteins from controls, and that this abnormality may be explained largely by variations in CSF apoE concentration.

Cerebral oxidative damage is a feature of aging and is increased in a number of neurodegenerative diseases. We pursued the gene-environment interaction of lack of apolipoprotein E (apoE) and modulation of dietary alpha-tocopherol on cerebral oxidative damage in aged male and female mice by quantifying the major isomers of cerebral isoprostanes, derived from arachidonic acid (AA) oxidation, and neuroprostanes, derived from docosahexaenoic acid (DHA) oxidation. Mice fed alpha-tocopherol-deficient, normal, or -supplemented diet had undetectable, 4486 +/- 215, or 6406 +/- 254 ng of alpha-tocopherol per gram of brain tissue (p < 0.0001), respectively. Two factors, male gender and lack of apoE, combined to increase cerebral AA oxidation by 28%, whereas three factors, male gender, lack of apoE, and deficiency in alpha-tocopherol, combined to increase cerebral DHA oxidation by 81%. alpha-Tocopherol supplementation decreased cerebral isoprostanes but not neuroprostanes and enhanced DHA, but not AA, endoperoxide reduction in vivo and in vitro. These results demonstrated that the interaction of gender, inherited susceptibilities, and dietary alpha-tocopherol contributed differently to oxidative damage to cerebral AA and DHA in aged mice.

Objective: To test the hypothesis that quantification of cerebrospinal fluid (CSF) F(2)-isoprostanes (F(2)-IsoPs), in vivo biomarkers of free radical damage, along with CSF Abeta(42) and tau levels improves laboratory diagnostic accuracy for Alzheimer disease (AD)., Participants: Patients with probable AD (n = 19), dementias other than AD (n = 8), and age-matched controls (n = 10)., Main Outcome Measures: Cerebrospinal fluid concentrations of Abeta(42) and tau were determined by a commercially available test (Athena Diagnostics, Worcester, Mass). Cerebrospinal fluid F(2)-IsoP levels were quantified by gas chromatography/mass spectrometry., Results: Individuals were classified as AD or non-AD by a published method using CSF Abeta(42) and tau levels (95% sensitivity, 50% specificity), by CSF F(2)-IsoP levels greater than 25 pg/mL and Abeta(42) concentrations less than 1125 pg/mL (90% sensitivity, 83% specificity), and by combined analysis using CSF F(2)-IsoP, Abeta(42), and tau levels (84% sensitivity, 89% specificity)., Conclusion: Cerebrospinal fluid F(2)-IsoP quantification may enhance the accuracy of the laboratory diagnosis of AD.

Increased generation of neurotoxic lipid peroxidation products is proposed to contribute to the pathogenesis of Alzheimer's disease (AD). Current antioxidant therapies are directed at limiting propagation of brain lipid peroxidation. Another approach would be to scavenge the reactive aldehyde products of lipid peroxidation. N(alpha)-acetyl-L-cysteine (NAC) and aminoguanidine (AG) react rapidly and irreversibly with 4-hydroxy-2-nonenal (HNE) in vitro, and both have been proposed as potential scavengers of HNE in biological systems. We have compared NAC, AG, and a series of congeners as scavengers of HNE and as neuroprotectants from HNE. Our results showed that while both NAC and AG had comparable chemical reactivity with HNE, only NAC and its congeners were able to block HNE-protein adduct formation in vitro and in neuronal cultures. Moreover, NAC and its congeners, but not AG, effectively protected brain mitochondrial respiration and neuronal microtubule structure from the toxic effects of HNE. We conclude that NAC and its congeners, but not AG, may act as neuroprotectants from HNE.

Interest in cerebrospinal fluid (CSF) lipoproteins has been stimulated by the association of certain alleles of the human apolipoprotein E gene (APOE) with an increased risk of Alzheimer's disease (AD), and because apolipoprotein E (apoE) is one of the major apolipoproteins in CSF. CSF lipoproteins (d < 1.210 g/ml fraction) are distinct from their plasma counterparts, and in AD patients CSF may contain novel particles. The protein concentration of CSF lipoproteins is reduced in AD patients. Moreover, the molecular distribution of apoE- and apoAII-containing apolipoproteins in CSF is dictated by APOE. The lipid composition suggests that CSF lipoproteins from AD patients may have undergone increased free radical-mediated damage; experimental data support the possibility that this may occur both before and after lipoprotein assembly. Finally, human CSF lipoproteins oxidized ex vivo are neurotoxic to neuronal cells in culture and disrupt microtubule structure, an activity not observed with oxidized bovine CSF lipoproteins. CSF lipoproteins may represent a means whereby apoE influences the outcome of free radical-mediated damage to brain., (Copyright 2000 Wiley-Liss, Inc.)

Aged homozygous apolipoprotein E gene-deficient (apoE -/-) mice have been proposed as an experimental model for the role of human apoE isoforms in Alzheimer's disease (AD). However, results from different laboratories have been in conflict regarding the presence or absence of neurodegeneration in these mice. Moreover, despite apoE being the major lipid trafficking molecule in the central nervous system, there has been no investigation of brain lipid levels in apoE -/- mice. Here we have examined male and female apoE -/- and control mice aged 10 to 12 months, testing the hypothesis that lack of apoE leads to some of the neuropathological changes seen in AD. Our results failed to demonstrate significant neurodegeneration, histopathological changes, or reduction in cerebral cortical synaptophysin in apoE -/- mice. However, we did observe a significant reduction in cerebral cortical phospholipids and their constituent fatty acids, as well as elevated lipid peroxidation products, in apoE -/- mice compared to apoE +/+ mice with the same genetic background. Our results suggest that the brains of aged apoE -/- mice display some of the lipid abnormalities associated with AD; however, these changes alone, at the magnitudes achieved in the apoE -/- mice, do not directly lead to the major neurodegenerative changes of AD.

The major apolipoproteins (apo) on human cerebrospinal fluid lipoproteins are apoA-I and apoE. Given the association between inheritance of the varepsilon4 allele of the apoE gene (APOE4) and increased susceptibility to Alzheimer's disease, we tested the hypothesis that cerebrospinal fluid apolipoproteins may be influenced by APOE genotype and Alzheimer's disease. Lipoprotein fractions (d < 1.210 g/ml) were isolated from cerebrospinal fluid obtained from individuals with different APOE genotypes and with or without pathologically verified Alzheimer's disease. Apolipoproteins were separated by SDS-polyacrylamide gel electrophoresis and identified by silver nitrate staining, Western blotting, and N-terminal amino acid sequencing. Four protein species were detected by silver nitrate staining in subjects with an APOE3 allele: apoA-I, apoE monomer, apoE-apoA-II heterodimer, and apoE homodimer. In APOE4 homozygotes, only apoA-I and apoE monomer were detected. ApoA-II homodimer was demonstrated in all subjects by Western blotting. The relative levels of apoE- and apoA-II-containing apolipoproteins correlated with APOE genotype but were not altered by Alzheimer's disease. In contrast to apoE, no apoA-II immunoreactivity was observed with pathological structures in Alzheimer's disease brain. These differences in cerebrospinal fluid apolipoproteins may influence lipoprotein trafficking and may be an element in the stratification of risk for Alzheimer's disease with APOE genotype.

Two major risk factors for late-onset familial and sporadic Alzheimer disease (AD), a leading cause of dementia worldwide, are increasing age and inheritance of the epsilon4 allele of the apolipoprotein E gene (APOE4). Several isoform-specific effects of apoE have been proposed; however, the mechanisms by which apoE isoforms influence the pathogenesis of AD are unknown. Also associated with AD is increased lipid peroxidation in the regions of the brain most damaged by disease. 4-hydroxynonenal (HNE), the most potent neurotoxic product of lipid peroxidation, is thought to be deleterious to cells through reactions with protein nucleophiles. We tested the hypothesis that accumulation of the most common forms of HNE-protein adducts, borohydride-reducible adducts, is associated with AD and examined whether there was a relationship to APOE. Our results demonstrated that reducible HNE adducts were increased in the hippocampus, entorhinal cortex, and temporal cortex of patients with AD. Furthermore, our data showed that the pattern of reducible HNE adduct accumulation was related to APOE genotype; AD patients homozygous for APOE4 had pyramidal neuron cytoplasmic accumulation of reducible HNE adducts, while AD APOE3 homozygotes had both pyramidal neuron and astrocyte accumulation of reducible HNE adducts. This is in contrast to our previous observations that a distinct HNE protein adduct, the pyrrole adduct, accumulates on neurofibrillary tangles in AD patients. We conclude that APOE genotype influences the cellular distribution of increased reducible HNE adduct accumulation in AD.

Alzheimer's disease (AD) is the most common form of dementia in the United States and has been associated with APOE genotype. Apolipoprotein (apo) E along with apoAI serve as the major apolipoproteins in the central nervous system; however, we are unaware of any study addressing lipoprotein metabolism in AD. We tested the hypothesis that lipoprotein metabolism is altered in patients with AD by isolating and characterizing ventricular fluid (VF) lipoproteins obtained during a rapid autopsy protocol from patients with AD and age-matched nondemented control patients. Our results demonstrated abnormalities in the protein and lipid constituents of VF lipoproteins from AD patients. Apolipoprotein concentration was reduced by half in AD patients relative to controls; however, there was no selective reduction in apoE or apoAI. In addition, cholesteryl ester fatty acids, but not phospholipid fatty acids, from AD patients demonstrated a significant reduction in some polyunsaturated fatty acids (18:2 and 22:6) and an enrichment in 18:0. None of these changes were directly related to APOE genotype. Our data indicate that VF lipoprotein composition is altered, at least terminally, in AD patients, and that these changes are not associated with APOE. These findings suggest that altered VF lipoprotein metabolism may be a component of AD pathogenesis.

Increasing age and inheritance of the epsilon 4 allele of apolipoprotein E (APOE4) are significant risk factors for sporadic and late onset familial Alzheimer disease (AD); however, the mechanisms by which either leads to AD are unknown. Numerous studies have associated advancing age with increased indices of oxidative challenge to brain, and with still further increased oxidative damage to relevant brain regions in AD patients. A major consequence of oxidative damage to brain is lipid peroxidation with production of the neurotoxic metabolite 4-hydroxy-2-nonenal (HNE). HNE reacts with protein to yield several adducts, including a pyrrole adduct that forms irreversibly in biological systems. Previously, we have shown in a small number of AD and control patients that HNE pyrrole adduct antiserum is immunoreactive with neurofibrillary tangles (NFT), and that this reactivity was significantly associated with inheritance of APOE4. Others have confirmed this pattern of immunoreactivity in AD brain but did not observe an association with APOE4. Herein, we have expanded the study group to 19 AD patients homozygous for APOE4 or APOE3, as well as 30 patients with other neurodegenerative diseases, including diffuse Lewy body disease, Pick's disease, progressive supranuclear palsy, Parkinson's disease, and human immunodeficiency virus-1 encephalitis. HNE pyrrole adduct immunoreactivity on NFT in AD patients was strongly associated with APOE4 homozygosity. With the exception of rare immunoreactive Pick bodies in one case of Pick's disease, no other structure was recognized by HNE pyrrole adduct antiserum in this series of patients. We propose that there is a significant difference between the interaction of apoE3 and apoE4 with lipid peroxidation in the brains of AD patients.

Cumulative oxidative damage, including lipid peroxidation, is a central component of cellular aging and is thought to play a role in the pathogenesis of late-onset Alzheimer's disease (AD). Lipid peroxidation produces several cytotoxic aldehydes, one of the most potent being 4-hydroxy-2-nonenal (HNE). We have shown previously that HNE is a potent neurotoxin that covalently modifies and cross-links neuronal cytoskeletal protein in neuroglial cultures, suggesting that HNE may contribute to the pathogenesis of AD. In addition to aging, inheritance of the epsilon 4 allele of APOE is the other major risk factor for development of late-onset AD; however, the mechanisms through which aging and apolipoprotein E isoforms may collaborate in the onset or progression of AD are not known. We tested the hypothesis that HNE may yield a particular type of protein modification, pyrrole adduction, and that this may contribute to the pathogenesis of AD. Our data demonstrated that HNE formed pyrrole adducts with protein. Polyclonal antiserum was raised that specifically recognized HNE pyrrole adducts, and immunohistochemical analysis was performed on hippocampus and temporal cortex of 10 patients with histologically verified AD. Pyramidal neuron cytoplasm was immunoreactive in 4 of 4 APOE4 homozygotes, 2 of 3 APOE3/4 heterozygotes, and none of 3 APOE3 homozygotes (P < 0.05). The pattern of staining was highly suggestive of neurofibrillary tangles as the primary immunoreactive structure. These data suggest that differences in neuronal protein modification by HNE may account in part for the APOE-associated stratification of risk for late-onset AD.

Purpose: To implement and test variants of chemical shift imaging (CSI) acquiring both free induction decays (FIDs) showing all dissolved-phase compartments and spin echoes for specifically assessing INLINEMATH Xe MR thermometry in a rat model of general hypothermia., Methods: Imaging was performed at 2.89 T. INLINEMATH Xe-derived temperature was compared to values from a rectal probe., Results: Global INLINEMATH (spin echo) for turbo spectroscopic imaging., Conclusion: INLINEMATH Xe enables precise temperature measurements in the rat's abdomen using both FID and spin-echo acquisitions with acquisition of spin echoes enabling most precise temperature measurements., (© 2022 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Eukaryotic initiation factor 4F (eIF-4F) is a three-subunit complex that binds the 5' cap structure (m7GpppX, where X is any nucleotide) of eukaryotic mRNAs. This factor facilitates ribosome binding by unwinding the secondary structure in the mRNA 5' noncoding region. The limiting component of the 4F complex is believed to be the 24-kDa cap-binding phosphoprotein, eIF-4E. In this report, we describe the phosphorylation of eIF-4E in response to expression of the tyrosine kinase oncoproteins pp60v-src and pp60c-src527F. The results suggest that eIF-4E functions as a downstream target of the phosphorylation cascade induced by tyrosine-specific protein kinases as well as by effectors of the mitogenic response.

Background: Early detection of dementia and cognitive decline is crucial for effective interventions and overall wellbeing. Although virtual reality (VR) tools offer potential advantages to traditional dementia screening tools, there is a lack of knowledge regarding older adults' acceptance of VR tools, as well as the predictors and features influencing their adoption. This study aims to (i) explore older adults' perceptions of the acceptability and usefulness of VR diagnostic tools for dementia, and (ii) identify demographic predictors of adoption and features of VR applications that contribute to future adoption among older adults. Methods: A cross-sectional study was conducted involving community-dwelling older adults who completed online questionnaires covering demographics, medical history, technology acceptance, previous usage, and perceived usefulness and barriers to VR adoption. Multiple linear regression was employed to assess relationships between sociodemographic factors, prior technology use, perceived ease, usefulness, and intention to adopt VR-based diagnostic tools. Results: Older adults (N = 77, Mage = 73.74, SD = 6.4) were predominantly female and born in English-speaking countries. Perceived usefulness of VR applications and educational attainment emerged as significant predictors of the likelihood to use VR applications for dementia screening. Generally, older adults showed acceptance of VR applications for healthcare and dementia screening. Fully immersive applications were preferred, and older adults were mostly willing to share electronic information from screening with their healthcare providers. Conclusions: The field of research on VR applications in healthcare is expanding. Understanding the demographic characteristics of populations that stand to benefit from healthcare innovations is critical for promoting adoption of digital health technologies and mitigating its barriers to access. [ABSTRACT FROM AUTHOR]

Background: Recent Alzheimer's disease (AD) discoveries are increasingly based on studies from a variety of omics technologies on large cohorts. Currently, there is no easily accessible resource for neuroscientists to browse, query, and visualize these complex datasets in a harmonized manner. Objective: Create an online portal of public omics datasets for AD research. Methods: We developed Alzheimer DataLENS, a web-based portal, using the R Shiny platform to query and visualize publicly available transcriptomics and genetics studies of AD on human cohorts. To ensure consistent representation of AD findings, all datasets were processed through a uniform bioinformatics pipeline. Results: Alzheimer DataLENS currently houses 2 single-nucleus RNA sequencing datasets, over 30 bulk RNA sequencing datasets from 19 brain regions and 3 cohorts, and 2 genome-wide association studies (GWAS). Available visualizations for single-nucleus data include bubble plots, heatmaps, and UMAP plots; for bulk expression data include box plots and heatmaps; for pathways include protein-protein interaction network plots; and for GWAS results include Manhattan plots. Alzheimer DataLENS also links to two other knowledge resources: the AD Progression Atlas and the Astrocyte Atlas. Conclusions: Alzheimer DataLENS is a valuable resource for investigators to quickly and systematically explore omics datasets and is freely accessible at . [ABSTRACT FROM AUTHOR]

Abnormal phosphorylation of the microtubule-binding protein tau in the brain is a key pathological marker for Alzheimer's disease and additional neurodegenerative tauopathies. However, how hyperphosphorylated tau causes cellular dysfunction or death that underlies neurodegeneration remains an unsolved question critical for the understanding of disease mechanism and the design of efficacious drugs. Using a recombinant hyperphosphorylated tau protein (p-tau) synthesized by the PIMAX approach, we examined how cells responded to the cytotoxic tau and explored means to enhance cellular resistance to tau attack. Upon p-tau uptake, the intracellular calcium levels rose promptly. Gene expression analyses revealed that p-tau potently triggered endoplasmic reticulum (ER) stress, unfolded protein response (UPR), ER stress-associated apoptosis, and pro-inflammation in cells. Proteomics studies showed that p-tau diminished heme oxygenase-1 (HO-1), an ER stress-associated anti-inflammation and anti-oxidative stress regulator, while stimulated the accumulation of MIOS and other proteins. p-Tau-induced ER stress-associated apoptosis and pro-inflammation are ameliorated by apomorphine, a brain-permeable prescription drug widely used to treat Parkinson's disease symptoms, and by overexpression of HO-1. Our results reveal probable cellular functions targeted by hyperphosphorylated tau. Some of these dysfunctions and stress responses have been linked to neurodegeneration in Alzheimer's disease. The observations that the ill effects of p-tau can be mitigated by a small compound and by overexpressing HO-1 that is otherwise diminished in the treated cells inform new directions of Alzheimer's disease drug discovery. [ABSTRACT FROM AUTHOR]

Background: Sequencing the mitochondrial genome has been increasingly important for the investigation of primary mitochondrial diseases (PMD) and mitochondrial genetics. To overcome the limitations originating from PCR-based mtDNA enrichment, we set out to develop and evaluate a PCR-independent approach in this study, named Pime-Seq (PCR-independent mtDNA enrichment and next generation Sequencing). Results: By using the optimized mtDNA enrichment procedure, the mtDNA reads ratio reached 88.0 ± 7.9% in the sequencing library when applied on human PBMC samples. We found the variants called by Pime-Seq were highly consistent among technical repeats. To evaluate the accuracy and reliability of this method, we compared Pime-Seq with lrPCR based NGS by performing both methods simultaneously on 45 samples, yielding 1677 concordant variants, as well as 146 discordant variants with low-level heteroplasmic fraction, in which Pime-Seq showed higher reliability. Furthermore, we applied Pime-Seq on 4 samples of PMD patients retrospectively, and successfully detected all the pathogenic mtDNA variants. In addition, we performed a prospective study on 192 apparently healthy pregnant women during prenatal screening, in which Pime-Seq identified pathogenic mtDNA variants in 4 samples, providing extra information for better health monitoring in these cases. Conclusions: Pime-Seq can obtain highly enriched mtDNA in a PCR-independent manner for high quality and reliable mtDNA deep-sequencing, which provides us an effective and promising tool for detecting mtDNA variants for both clinical and research purposes. [ABSTRACT FROM AUTHOR]

Some individuals show a discrepancy between cognition and the amount of neuropathological changes characteristic for Alzheimer's disease (AD). This phenomenon has been referred to as 'resilience'. The molecular and cellular underpinnings of resilience remain poorly understood. To obtain an unbiased understanding of the molecular changes underlying resilience, we investigated global changes in gene expression in the superior frontal gyrus of a cohort of cognitively and pathologically well-defined AD patients, resilient individuals and age-matched controls (n = 11–12 per group). 897 genes were significantly altered between AD and control, 1121 between resilient and control and 6 between resilient and AD. Gene set enrichment analysis (GSEA) revealed that the expression of metallothionein (MT) and of genes related to mitochondrial processes was higher in the resilient donors. Weighted gene co-expression network analysis (WGCNA) identified gene modules related to the unfolded protein response, mitochondrial processes and synaptic signaling to be differentially associated with resilience or dementia. As changes in MT, mitochondria, heat shock proteins and the unfolded protein response (UPR) were the most pronounced changes in the GSEA and/or WGCNA, immunohistochemistry was used to further validate these processes. MT was significantly increased in astrocytes in resilient individuals. A higher proportion of the mitochondrial gene MT-CO1 was detected outside the cell body versus inside the cell body in the resilient compared to the control group and there were higher levels of heat shock protein 70 (HSP70) and X-box-binding protein 1 spliced (XBP1s), two proteins related to heat shock proteins and the UPR, in the AD donors. Finally, we show evidence for putative sex-specific alterations in resilience, including gene expression differences related to autophagy in females compared to males. Taken together, these results show possible mechanisms involving MTs, mitochondrial processes and the UPR by which individuals might maintain cognition despite the presence of AD pathology. [ABSTRACT FROM AUTHOR]

During growth phase, antlers exhibit a very rapid rate of chondrogenesis. The antler is formed from its growth center reserve mesenchyme (RM) cells, which have been found to be the derivatives of paired related homeobox 1 (Prrx1)-positive periosteal cells. However, the underlying mechanism that drives rapid chondrogenesis is not known. Herein, the miRNA expression profiles and chromatin states of three tissue layers (RM, precartilage, and cartilage) at different stages of differentiation within the antler growth center were analyzed by RNA-sequencing and ATAC-sequencing. We found that miR-140-3p was the miRNA that exhibited the greatest degree of upregulation in the rapidly growing antler, increasing from the RM to the cartilage layer. We also showed that Prrx1 was a key upstream regulator of miR-140-3p, which firmly confirmed by Prrx1 CUT&Tag sequencing of RM cells. Through multiple approaches (three-dimensional chondrogenic culture and xenogeneic antler model), we demonstrated that Prrx1 and miR-140-3p functioned as reciprocal negative feedback in the antler growth center, and downregulating PRRX1/upregulating miR-140-3p promoted rapid chondrogenesis of RM cells and xenogeneic antler. Thus, we conclude that the reciprocal negative feedback between Prrx1 and miR-140-3p is essential for balancing mesenchymal proliferation and chondrogenic differentiation in the regenerating antler. We further propose that the mechanism underlying chondrogenesis in the regenerating antler would provide a reference for helping understand the regulation of human cartilage regeneration and repair. [ABSTRACT FROM AUTHOR]

The 25 kDa-sized protein Lipocalin 2 (LCN2) was originally isolated from human neutrophil granulocytes more than 30 years ago. LCN2 is an emerging player in innate immune defense, as it reduces bacterial growth due to its ability to sequester iron-containing bacterial siderophores. On the other hand, LCN2 also serves as a transporter for various hydrophobic substances due to its β-barrel shaped structure. Over the years, LCN2 has been detected in many other cell types including epithelial cells, astrocytes, and hepatocytes. Studies have clearly shown that aberrant expression of LCN2 is associated with a variety of disorders and malignancies, including several diseases of the reproductive system. Furthermore, LCN2 was proposed as a non-invasive prognostic and/or diagnostic biomarker in this context. Although several studies have shed light on the role of LCN2 in various disorders of the female and male reproductive systems, including tumorigenesis, a comprehensive understanding of the physiological function of LCN2 in the reproductive tract is still lacking. However, there is evidence that LCN2 is directly related to fertility, as global depletion of Lcn2 in mice has a negative effect on their pregnancy rate. Since LCN2 expression can be regulated by steroid hormones, it is not surprising that its expression fluctuates greatly during remodeling processes in the female reproductive tract, especially in the uterus. Well-founded details about the expression and regulation of LCN2 in a healthy reproductive state and also about possible changes during reproductive aging could contribute to a better understanding of LCN2 as a target in various diseases. Therefore, the present review summarizes current knowledge about LCN2 in the reproductive system, including studies in rodents and humans, and discusses changes in LCN2 expression during pathological events. The limited data suggest that LCN2 is expressed and regulated differently in healthy male and female reproductive organs. [ABSTRACT FROM AUTHOR]

Background: Apolipoproteins and contactin 5 are proteins associated with Alzheimer's disease (AD) pathophysiology. Apolipoproteins act on transport and clearance of cholesterol and phospholipids during synaptic turnover and terminal proliferation. Contactin 5 is a neuronal membrane protein involved in key processes of neurodevelopment. Objective: To investigate the interactions between contactin 5 and apolipoproteins in AD, and the role of these proteins in response to neuronal damage. Methods: Apolipoproteins (measured by Luminex), contactin 5 (measured by Olink's proximity extension assay), and cholesterol (measured by liquid chromatography mass spectrometry) were assessed in the cerebrospinal fluid (CSF) and plasma of cognitively unimpaired participants (n = 93). Gene expression was measured using polymerase chain reaction in the frontal cortex of autopsied-confirmed AD (n = 57) and control subjects (n = 31) and in the hippocampi of mice following entorhinal cortex lesions. Results: Contactin 5 positively correlated with apolipoproteins B (p = 5.4×10–8), D (p = 1.86×10–4), E (p = 2.92×10–9), J (p = 2.65×10–9), and with cholesterol (p = 0.0096) in the CSF, and with cholesterol (p = 0.02), HDL (p = 0.0143), and LDL (p = 0.0121) in the plasma. Negative correlations were seen between CNTN5, APOB (p = 0.034) and APOE (p = 0.015) mRNA levels in the brains of control subjects. In the mouse model, apoe and apoj gene expression increased during the reinnervation phase (p < 0.05), while apob (p = 0.023) and apod (p = 0.006) increased in the deafferentation stage. Conclusions: Extensive interactions were observed between contactin 5 and apolipoproteins and cholesterol, possibly due to neuronal damage. The alterations in gene expression of apolipoproteins suggest a role in axonal, terminal, and synaptic remodeling in response to entorhinal cortex damage. [ABSTRACT FROM AUTHOR]

Eukaryotic cellular mRNAs have a 5' cap structure (m7 GpppX) that facilitates binding to ribosomes and is required for efficient translation. A specific initiation factor, eIF-4F, mediates the function of the cap and consists of three subunits, one of which, eIF-4E, binds the cap. This subunit is present in limiting amounts in the cell, and is thought to be regulated by phosphorylation: decreased phosphorylation of eIF-4E following various treatments correlates with a decrease in cellular translation rate. These observations suggest that eIF-4E lies on the mitogenic signal transduction pathway, and we reasoned that overexpression of eIF-4E might profoundly affect cellular growth properties. We report here that overexpression of eIF-4E in NIH 3T3 and Rat 2 fibroblasts causes their tumorigenic transformation as determined by three criteria: formation of transformed foci on a monolayer of cells; anchorage-independent growth; and tumour formation in nude mice.

Increased phosphorylation of ribosomal protein S6 has been extensively correlated with an increased rate of protein synthesis. We report here that under two separate conditions in Ehrlich cells an increase in the level of S6 phosphorylation does not result in any increase in the rate of protein synthesis. 1) In glutamine-deprived cells TPA stimulates S6 phosphorylation but has no effect on the rate of protein synthesis, 2) In cells deprived of serum growth factors, addition of serum stimulates both S6 phosphorylation and protein synthesis while TPA stimulates only S6 phosphorylation. These results show that increased phosphorylation of S6 is not sufficient to cause increased rates of protein synthesis, and suggest that additional factors may play a more direct role.

Transcription factors (TFs) orchestrating lineage-development often control genes required for cellular survival. However, it is not well understood how cells survive when such TFs are lost, for example in cancer. PU.1 is an essential TF for myeloid fate, and mice with downregulated PU.1 levels develop acute myeloid leukemia (AML). Combining a multi-omics approach with a functional genetic screen, we reveal that PU.1-downregulated cells fundamentally change their survival control from cytokine-driven pathways to overexpression of an autophagy-predominated stem cell gene program, for which we also find evidence in human AML. Control of this program involves redirected chromatin occupancy of the PU.1 partner TF Runx1 to a lineage-inappropriate binding site repertoire. Hence, genomic reallocation of TF binding upon loss of a partner TF can act as a pro-oncogenic failsafe mechanism by sustaining cell survival during leukemogenesis., Competing Interests: Disclosure and competing interests statement The authors declare no competing interests., (© 2024. The Author(s).)

Reactive oxygen species (ROS) are metabolic by-products that constitute an indispensable component of physiological processes, albeit their heightened presence may proffer substantial perils to biological entities. Such a proliferation gives rise to a gradual escalation of oxidative stress within the organism, thereby compromising mitochondrial functionality and inflicting harm upon various bodily systems, with a particular predilection for the central nervous system. In its nascent stages, it is plausible that inflammation has been a facilitator in the progression of the malady. The precise role of inflammation in Alzheimer's disease (AD) remains somewhat enigmatic, although it is conceivable that activated microglia and astrocytes might be implicated in the removal of amyloid-β (Aβ) deposits. Nonetheless, prolonged microglial activation is associated with Tau phosphorylation and Aβ aggregation. Research studies have indicated that AD brains upregulate complementary molecules, inflammatory cytokines, acute phase reacting agents, and other inflammatory mediators that may cause neurodegeneration. In this review, oxidative damage products will be discussed as potential peripheral biomarkers for AD and its early stages. The disordered excretion of pro-inflammatory cytokines, chemokines, oxygen, and nitrogen-reactive species, along with the stimulation of the complement system by glial cells, has the potential to disrupt the functionality of neuronal termini. This perturbation, in turn, culminates in compromised synaptic function, a phenomenon empirically linked to the manifestation of cognitive impairments. The management of neurodegenerative conditions in the context of dementia necessitates therapeutic interventions that specifically target the excessive production of inflammatory and oxidative agents. Furthermore, we shall deliberate upon the function of microglia and oxidative injury in the etiology of AD and the ensuing neurodegenerative processes., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Microglia are highly dynamic cells that play a critical role in tissue homeostasis through the surveillance of brain parenchyma and response to cues associated with damage. Aging and APOE4 genotype are the strongest risk factors for Alzheimer’s disease (AD), but how they affect microglial dynamics remains unclear. Using ex vivo confocal microscopy, we analyzed microglial dynamic behaviors in the entorhinal cortex (EC) and hippocampus CA1 of 6-, 12-, and 21-month-old mice APOE3 or APOE4 knock-in mice expressing GFP under the CX3CR1 promoter. To study microglia surveillance, we imaged microglia baseline motility for 20 min and measured the extension and retraction of processes. We found that APOE4 microglia exhibited significantly less brain surveillance (27%) compared to APOE3 microglia in 6-month-old mice; aging exacerbated this deficit. To measure microglia response to damage, we imaged process motility in response to ATP, an injury-associated signal, for 30 min. We found APOE4 microglia extended their processes significantly slower (0.9 µm/min, p < 0.005) than APOE3 microglia (1.1 μm/min) in 6-month-old animals. APOE-associated alterations in microglia motility were observed in 12- and 21-month-old animals, and this effect was exacerbated with aging in APOE4 microglia. We measured protein and mRNA levels of P2RY12, a core microglial receptor required for process movement in response to damage. We found that APOE4 microglia express significantly less P2RY12 receptors compared to APOE3 microglia despite no changes in P2RY12 transcripts. To examine if the effect of APOE4 on the microglial response to ATP also applied to amyloid β (Aβ), we infused locally Hi-Lyte Fluor 555-labeled Aβ in acute brain slices of 6-month-old mice and imaged microglia movement for 2 h. APOE4 microglia showed a significantly slower (p < 0.0001) process movement toward the Aβ, and less Aβ coverage at early time points after Aβ injection. To test whether P2RY12 is involved in process movement in response to Aβ, we treated acute brain slices with a P2RY12 antagonist before Aβ injection; microglial processes no longer migrated towards Aβ. These results provide mechanistic insights into the impact of APOE4 genotype and aging in dynamic microglial behaviors prior to gross Aβ pathology and could help explain how APOE4 brains are more susceptible to AD pathogenesis. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease neuropathologic changes (AD-NC) are important to identify people with high risk for AD dementia (ADD) and subtyping ADD. Objective: Develop imputation models based on clinical measures to infer AD-NC. Methods: We used penalized generalized linear regression to train imputation models for four AD-NC traits (amyloid-β, tangles, global AD pathology, and pathologic AD) in Rush Memory and Aging Project decedents, using clinical measures at the last visit prior to death as predictors. We validated these models by inferring AD-NC traits with clinical measures at the last visit prior to death for independent Religious Orders Study (ROS) decedents. We inferred baseline AD-NC traits for all ROS participants at study entry, and then tested if inferred AD-NC traits at study entry predicted incident ADD and postmortem pathologic AD. Results: Inferred AD-NC traits at the last visit prior to death were related to postmortem measures with R2 = (0.188,0.316,0.262) respectively for amyloid-β, tangles, and global AD pathology, and prediction Area Under the receiver operating characteristic Curve (AUC) 0.765 for pathologic AD. Inferred baseline levels of all four AD-NC traits predicted ADD. The strongest prediction was obtained by the inferred baseline probabilities of pathologic AD with AUC = (0.919,0.896) for predicting the development of ADD in 3 and 5 years from baseline. The inferred baseline levels of all four AD-NC traits significantly discriminated pathologic AD profiled eight years later with p-values < 1.4×10-10. Conclusions: Inferred AD-NC traits based on clinical measures may provide effective AD biomarkers that can estimate the burden of AD-NC traits in aging adults. [ABSTRACT FROM AUTHOR]

Glioblastoma (GB), the most common and aggressive brain tumor, demonstrates intrinsic resistance to current therapies, resulting in poor clinical outcomes. Cancer progression can be partially attributed to the deregulation of protein translation mechanisms that drive cancer cell growth. In this study, we present the translatome landscape of GB as a valuable data resource. Eight patient-derived GB sphere cultures (GSCs) were analyzed using ribosome profiling and messenger RNA (mRNA) sequencing. We investigated inter-cell-line differences through differential expression analysis at both the translatome and transcriptome levels. Translational changes post-radiotherapy were assessed at 30 and 60 min. The translation of non-coding RNAs (ncRNAs) was validated using in-house and public mass spectrometry (MS) data, whereas RNA expression was confirmed by quantitative PCR (qPCR). Our findings demonstrate that ribosome sequencing provides more detailed information than MS or transcriptional analyses. Transcriptional similarities among GSCs correlate with translational similarities, aligning with previously defined subtypes such as proneural and mesenchymal. Additionally, we identified a broad spectrum of open reading frame types in both coding and non-coding mRNA regions, including long non-coding RNAs (lncRNAs) and pseudogenes undergoing active translation. Translation of ncRNAs into peptides was independently confirmed by in-house data and external MS data. We also observed that translational regulation of histones (downregulated) and splicing factors (upregulated) occurs in response to radiotherapy. These data offer new insights into genome-wide protein synthesis, identifying translationally regulated genes and alternative translation initiation sites in GB under normal and radiotherapeutic conditions, providing a rich resource for GB research. Further functional validation of differentially expressed genes after radiotherapy is needed. Understanding translational control in GB can reveal mechanistic insights and identify currently unknown biomarkers, ultimately enhancing the diagnosis and treatment of this aggressive brain cancer., (© 2024 The Author(s). Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)