Showing papers in "Acta neuropathologica communications in 2023"
TL;DR: In the context of aging, injury, or neuroinflammation, activated microglia signaling with TNF-α, IL-1α, and C1q induces a neurotoxic astrocytic phenotype, classified as A1, A1-like or neuroinflammatory reactive astrocell as mentioned in this paper .
Abstract: In the contexts of aging, injury, or neuroinflammation, activated microglia signaling with TNF-α, IL-1α, and C1q induces a neurotoxic astrocytic phenotype, classified as A1, A1-like, or neuroinflammatory reactive astrocytes. In contrast to typical astrocytes, which promote neuronal survival, support synapses, and maintain blood-brain barrier integrity, these reactive astrocytes downregulate supportive functions and begin to secrete neurotoxic factors, complement components like C3, and chemokines like CXCL10, which may facilitate recruitment of immune cells across the BBB into the CNS. The proportion of pro-inflammatory reactive astrocytes increases with age through associated microglia activation, and these pro-inflammatory reactive astrocytes are particularly abundant in neurodegenerative disorders. As the identification of astrocyte phenotypes progress, their molecular and cellular effects are characterized in a growing array of neuropathologies.
6 citations
TL;DR: In this paper , the impact of hypertension on perivascular-and neuroinflammation in both white matter hyperintensities (WMH) and normal-appearing white matter (NAWM) was investigated.
Abstract: The major vascular cause of dementia is cerebral small vessel disease (SVD), including white matter hyperintensities (WMH) amongst others. While the underlying pathology of SVD remains unclear, chronic hypertension and neuroinflammation are recognized as important risk factors for SVD and for the conversion of normal-appearing white matter (NAWM) to WMH. Unfortunately, most studies investigating the role of neuroinflammation in WMH relied on peripheral blood markers, e.g., markers for systemic or vascular inflammation, as a proxy for inflammation in the brain itself. However, it is unknown whether such markers accurately capture inflammatory changes within the cerebral white matter. Therefore, we aimed to comprehensively investigate the impact of hypertension on perivascular- and neuroinflammation in both WMH and NAWM. We conducted high field brain magnetic resonance imaging (MRI), followed by (immuno-)histopathological staining of neuroinflammatory markers on human post-mortem brains of elderly people with a history of hypertension (n = 17) and age-matched normotensive individuals (n = 5). MRI images were co-registered to (immuno-)histopathological data including stainings for microglia and astroglia to assess changes in MRI-based WMH at microscopic resolution. Perivascular inflammation was carefully assessed based on the severity of perivascular astrogliosis of the smallest vessels throughout white matter regions. Hypertension was associated with a larger inflammatory response in both WMH and NAWM. Notably, the presence of close-range perivascular inflammation was twice as common among those with hypertension than in controls both in WMH and NAWM, suggesting that neurovascular inflammation is critical in the etiology of WMH. Moreover, a higher degree of microglial activation was related to a higher burden of WMH. Our results indicate that neuro(vascular)inflammation at the level of the brain itself is involved in the etiology of WMH. Future therapeutic strategies focusing on multitarget interventions including antihypertensive treatment as well as neuroinflammation may ameliorate WMH progression.
6 citations
TL;DR: In this article , electron cryo-microscopy (cryo-EM) of tau filaments from two cases of sclerosing panencephalitis was used to show that the tau folds of SSPE and CTE are identical.
Abstract: Abstract Subacute sclerosing panencephalitis (SSPE) occurs in some individuals after measles infection, following a symptom-free period of several years. It resembles chronic traumatic encephalopathy (CTE), which happens after repetitive head impacts or exposure to blast waves, following a symptom-free period. As in CTE, the neurofibrillary changes of SSPE are concentrated in superficial cortical layers. Here we used electron cryo-microscopy (cryo-EM) of tau filaments from two cases of SSPE to show that the tau folds of SSPE and CTE are identical. Two types of filaments were each made of two identical protofilaments with an extra density in the β-helix region. Like in CTE, the vast majority of tau filaments were Type I, with a minority of Type II filaments. These findings suggest that the CTE tau fold can be caused by different environmental insults, which may be linked by inflammatory changes.
5 citations
TL;DR: In this article , the authors used RNA sequencing data to analyze the transcriptome profiles of 43 primary-relapse medulloblastoma (MB) pairs in order to identify specific molecular features of relapses within various tumor groups.
Abstract: Abstract Nowadays medulloblastoma (MB) tumors can be treated with risk-stratified approaches with up to 80% success rate. However, disease relapses occur in approximately 30% of patients and successful salvage treatment strategies at relapse remain scarce. Acquired copy number changes or TP53 mutations are known to occur frequently in relapses, while methylation profiles usually remain highly similar to those of the matching primary tumors, indicating that in general molecular subgrouping does not change during the course of the disease. In the current study, we have used RNA sequencing data to analyze the transcriptome profiles of 43 primary-relapse MB pairs in order to identify specific molecular features of relapses within various tumor groups. Gene variance analysis between primary and relapse samples demonstrated the impact of age in SHH-MB: the changes in gene expression relapse profiles were more pronounced in the younger patients (< 10 years old), which were also associated with increased DNA aberrations and somatic mutations at relapse probably driving this effect. For Group 3/4 MB transcriptome data analysis uncovered clear sets of genes either active or decreased at relapse that are significantly associated with survival, thus could be potential predictive markers. In addition, deconvolution analysis of bulk transcriptome data identified progression-associated differences in cell type enrichment. The proportion of undifferentiated progenitors increased in SHH-MB relapses with a concomitant decrease of differentiated neuron-like cells, while in Group 3/4 MB relapses cell cycle activity increases and differentiated neuron-like cells proportion decreases as well. Thus, our findings uncovered significant transcriptome changes in the molecular signatures of relapsed MB and could be potentially useful for further clinical purposes.
3 citations
TL;DR: In this paper , the authors found that retinal degeneration constitutes an early pathological event that directly affects the control of circadian rhythm in Alzheimer's disease (AD) in transgenic APP/PS1 mice.
Abstract: Abstract The circadian clock is synchronized to the 24 h day by environmental light which is transmitted from the retina to the suprachiasmatic nucleus (SCN) primarily via the retinohypothalamic tract (RHT). Circadian rhythm abnormalities have been reported in neurodegenerative disorders such as Alzheimer's disease (AD). Whether these AD-related changes are a result of the altered clock gene expression, retina degeneration, including the dysfunction in RHT transmission, loss of retinal ganglion cells and its electrophysiological capabilities, or a combination of all of these pathological mechanisms, is not known. Here, we evaluated transgenic APP/PS1 mouse model of AD and wild-type mice at 6- and 12-month-old, as early and late pathological stage, respectively. We noticed the alteration of circadian clock gene expression not only in the hypothalamus but also in two extra-hypothalamic brain regions, cerebral cortex and hippocampus, in APP/PS1 mice. These alterations were observed in 6-month-old transgenic mice and were exacerbated at 12 months of age. This could be explained by the reduced RHT projections in the SCN of APP/PS1 mice, correlating with downregulation of hypothalamic GABAergic response in APP/PS1 mice in advanced stage of pathology. Importantly, we also report retinal degeneration in APP/PS1 mice, including Aβ deposits and reduced choline acetyltransferase levels, loss of melanopsin retinal ganglion cells and functional integrity mainly of inner retina layers. Our findings support the theory that retinal degeneration constitutes an early pathological event that directly affects the control of circadian rhythm in AD.
3 citations
TL;DR: In this article , site-directed mutagenesis was used to map the domains involved in protein-protein interaction and showed that some of them are required for membrane trafficking of the Popeye domain containing (POPDC) proteins.
Abstract: Abstract The Popeye domain containing (POPDC) genes encode sarcolemma-localized cAMP effector proteins. Mutations in blood vessel epicardial substance ( BVES ) also known as POPDC1 and POPDC2 have been associated with limb-girdle muscular dystrophy and cardiac arrhythmia. Muscle biopsies of affected patients display impaired membrane trafficking of both POPDC isoforms. Biopsy material of patients carrying mutations in BVES were immunostained with POPDC antibodies. The interaction of POPDC proteins was investigated by co-precipitation, proximity ligation, bioluminescence resonance energy transfer and bimolecular fluorescence complementation. Site-directed mutagenesis was utilised to map the domains involved in protein–protein interaction. Patients carrying a novel homozygous variant, BVES (c.547G > T, p.V183F) displayed only a skeletal muscle pathology and a mild impairment of membrane trafficking of both POPDC isoforms. In contrast, variants such as BVES p.Q153X or POPDC2 p.W188X were associated with a greater impairment of membrane trafficking. Co-transfection analysis in HEK293 cells revealed that POPDC proteins interact with each other through a helix-helix interface located at the C-terminus of the Popeye domain. Site-directed mutagenesis of an array of ultra-conserved hydrophobic residues demonstrated that some of them are required for membrane trafficking of the POPDC1–POPDC2 complex. Mutations in POPDC proteins that cause an impairment in membrane localization affect POPDC complex formation while mutations which leave protein–protein interaction intact likely affect some other essential function of POPDC proteins.
3 citations
TL;DR: In this article , the role of insulin-like growth factor-1 (IGF-1) signaling in the development of the central nervous system (CNS) and regulates neuronal survival and myelination in the adult CNS was investigated.
Abstract: Signaling by insulin-like growth factor-1 (IGF-1) is essential for the development of the central nervous system (CNS) and regulates neuronal survival and myelination in the adult CNS. In neuroinflammatory conditions including multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), IGF-1 can regulate cellular survival and activation in a context-dependent and cell-specific manner. Notwithstanding its importance, the functional outcome of IGF-1 signaling in microglia/macrophages, which maintain CNS homeostasis and regulate neuroinflammation, remains undefined. As a result, contradictory reports on the disease-ameliorating efficacy of IGF-1 are difficult to interpret, together precluding its potential use as a therapeutic agent. To fill this gap, we here investigated the role of IGF-1 signaling in CNS-resident microglia and border associated macrophages (BAMs) by conditional genetic deletion of the receptor Igf1r in these cell types. Using a series of techniques including histology, bulk RNA sequencing, flow cytometry and intravital imaging, we show that absence of IGF-1R significantly impacted the morphology of both BAMs and microglia. RNA analysis revealed minor changes in microglia. In BAMs however, we detected an upregulation of functional pathways associated with cellular activation and a decreased expression of adhesion molecules. Notably, genetic deletion of Igf1r from CNS-resident macrophages led to a significant weight gain in mice, suggesting that absence of IGF-1R from CNS-resident myeloid cells indirectly impacts the somatotropic axis. Lastly, we observed a more severe EAE disease course upon Igf1r genetic ablation, thus highlighting an important immunomodulatory role of this signaling pathway in BAMs/microglia. Taken together, our work shows that IGF-1R signaling in CNS-resident macrophages regulates the morphology and transcriptome of these cells while significantly decreasing the severity of autoimmune CNS inflammation.
3 citations
TL;DR: In this paper , the authors use single nucleus RNA sequencing of human post-mortem white matter samples from the brain, cerebellum and spinal cord and subsequent tissue-based validation to identify region-specific oligodendrocyte precursor cells that retain developmental origin markers into adulthood, distinguishing them from mouse OPCs.
Abstract: Abstract The myelinated white matter tracts of the central nervous system (CNS) are essential for fast transmission of electrical impulses and are often differentially affected in human neurodegenerative diseases across CNS region, age and sex. We hypothesize that this selective vulnerability is underpinned by physiological variation in white matter glia. Using single nucleus RNA sequencing of human post-mortem white matter samples from the brain, cerebellum and spinal cord and subsequent tissue-based validation we found substantial glial heterogeneity with tissue region: we identified region-specific oligodendrocyte precursor cells (OPCs) that retain developmental origin markers into adulthood, distinguishing them from mouse OPCs. Region-specific OPCs give rise to similar oligodendrocyte populations, however spinal cord oligodendrocytes exhibit markers such as SKAP2 which are associated with increased myelin production and we found a spinal cord selective population particularly equipped for producing long and thick myelin sheaths based on the expression of genes/proteins such as HCN2 . Spinal cord microglia exhibit a more activated phenotype compared to brain microglia, suggesting that the spinal cord is a more pro-inflammatory environment, a difference that intensifies with age. Astrocyte gene expression correlates strongly with CNS region, however, astrocytes do not show a more activated state with region or age. Across all glia, sex differences are subtle but the consistent increased expression of protein-folding genes in male donors hints at pathways that may contribute to sex differences in disease susceptibility. These findings are essential to consider for understanding selective CNS pathologies and developing tailored therapeutic strategies.
3 citations
TL;DR: In this paper , the effects of the associated SNPs not directly linked to the amino acid exchange in TMEM106B are analyzed by crossing Tmem106b T186S mice with Grn −/− knockout mice, a model for GRN -mediated FTLD.
Abstract: Abstract Genetic variants in TMEM106B are a common risk factor for frontotemporal lobar degeneration and the most important modifier of disease risk in patients with progranulin ( GRN ) mutations (FTLD- GRN ). TMEM106B is encoding a lysosomal transmembrane protein of unknown molecular function. How it mediates its disease-modifying function remains enigmatic. Several TMEM106B single nucleotide polymorphisms (SNPs) are significantly associated with disease risk in FTLD-GRN carriers, of which all except one are within intronic sequences of TMEM106B . Of note, the non-coding SNPs are in high linkage disequilibrium with the coding SNP rs3173615 located in exon six of TMEM106B, resulting in a threonine to serine change at amino acid 185 in the minor allele, which is protective in FTLD- GRN carriers. To investigate the functional consequences of this variant in vivo, we generated and characterized a knockin mouse model harboring the Tmem106b T186S variant. We analyzed the effect of this protective variant on FTLD pathology by crossing Tmem106b T186S mice with Grn −/− knockout mice, a model for GRN -mediated FTLD. We did not observe the amelioration of any of the investigated Grn −/− knockout phenotypes, including transcriptomic changes, lipid alterations, or microgliosis in Tmem106b T186S/T186S × Grn −/− mice, indicating that the Tmem106b T186S variant is not protective in the Grn −/− knockout mouse model. These data suggest that effects of the associated SNPs not directly linked to the amino acid exchange in TMEM106B are critical for the modifying effect.
2 citations
TL;DR: The authors developed a multiplex immunohistochemistry approach (visualizing the immunostain with brightfield microscopy) to examine pathological alterations in the aging human brain in health and disease states.
Abstract: Abstract New histological techniques are needed to examine protein distribution in human tissues, which can reveal cell shape and disease pathology connections. Spatial proteomics has changed the study of tumor microenvironments by identifying spatial relationships of immunomodulatory cells and proteins and contributing to the discovery of new cancer immunotherapy biomarkers. However, the fast-expanding toolkit of spatial proteomic approaches has yet to be systematically applied to investigate pathological alterations in the aging human brain in health and disease states. Moreover, post-mortem human brain tissue presents distinct technical problems due to fixation procedures and autofluorescence, which limit fluorescence methodologies. This study sought to develop a multiplex immunohistochemistry approach (visualizing the immunostain with brightfield microscopy). Quantitative multiplex Immunohistochemistry with Visual colorimetric staining to Enhance Regional protein localization (QUIVER) was developed to address these technical challenges. Using QUIVER, a ten-channel pseudo-fluorescent image was generated using chromogen removal and digital microscopy to identify unique molecular microglia phenotypes. Next, the study asked if the tissue environment, specifically the amyloid plaques and neurofibrillary tangles characteristic of Alzheimer's disease, has any bearing on microglia's cellular and molecular phenotypes. QUIVER allowed the visualization of five molecular microglia/macrophage phenotypes using digital pathology tools. The recognizable reactive and homeostatic microglia/macrophage phenotypes demonstrated spatial polarization towards and away from amyloid plaques, respectively. Yet, microglia morphology appearance did not always correspond to molecular phenotype. This research not only sheds light on the biology of microglia but also offers QUIVER, a new tool for examining pathological alterations in the brains of the elderly.
2 citations
TL;DR: In this paper , the MAPT haplotype influences expression of MAPT and SNCA, encoding the protein α-synuclein (α-syn), on mRNA and protein levels in postmortem brains of PD patients and controls.
Abstract: Abstract The MAPT gene, encoding the microtubule-associated protein tau on chromosome 17q21.31, is result of an inversion polymorphism, leading to two allelic variants (H1 and H2). Homozygosity for the more common haplotype H1 is associated with an increased risk for several tauopathies, but also for the synucleinopathy Parkinson’s disease (PD). In the present study, we aimed to clarify whether the MAPT haplotype influences expression of MAPT and SNCA , encoding the protein α-synuclein (α-syn), on mRNA and protein levels in postmortem brains of PD patients and controls. We also investigated mRNA expression of several other MAPT haplotype-encoded genes. Postmortem tissues from cortex of fusiform gyrus (ctx-fg) and of the cerebellar hemisphere (ctx-cbl) of neuropathologically confirmed PD patients ( n = 95) and age- and sex-matched controls ( n = 81) were MAPT haplotype genotyped to identify cases homozygous for either H1 or H2. Relative expression of genes was quantified using real-time qPCR; soluble and insoluble protein levels of tau and α-syn were determined by Western blotting. Homozygosity for H1 versus H2 was associated with increased total MAPT mRNA expression in ctx-fg regardless of disease state. Inversely, H2 homozygosity was associated with markedly increased expression of the corresponding antisense MAPT-AS1 in ctx-cbl. PD patients had higher levels of insoluble 0N3R and 1N4R tau isoforms regardless of the MAPT genotype. The increased presence of insoluble α-syn in PD patients in ctx-fg validated the selected postmortem brain tissue. Our findings in this small, but well controlled cohort of PD and controls support a putative biological relevance of tau in PD. However, we did not identify any link between the disease-predisposing H1/H1 associated overexpression of MAPT with PD status. Further studies are required to gain a deeper understanding of the potential regulatory role of MAPT-AS1 and its association to the disease-protective H2/H2 condition in the context of PD.
TL;DR: In this article , the most common malignant brain tumor in children, medulloblastoma (MB), is subdivided into four clinically relevant molecular subgroups, although targeted therapy options informed by understanding of different cellular features are lacking.
Abstract: Abstract The most common malignant brain tumour in children, medulloblastoma (MB), is subdivided into four clinically relevant molecular subgroups, although targeted therapy options informed by understanding of different cellular features are lacking. Here, by comparing the most aggressive subgroup (Group 3) with the intermediate (SHH) subgroup, we identify crucial differences in tumour heterogeneity, including unique metabolism-driven subpopulations in Group 3 and matrix-producing subpopulations in SHH. To analyse tumour heterogeneity, we profiled individual tumour nodules at the cellular level in 3D MB hydrogel models, which recapitulate subgroup specific phenotypes, by single cell RNA sequencing (scRNAseq) and 3D OrbiTrap Secondary Ion Mass Spectrometry (3D OrbiSIMS) imaging. In addition to identifying known metabolites characteristic of MB, we observed intra- and internodular heterogeneity and identified subgroup-specific tumour subpopulations. We showed that extracellular matrix factors and adhesion pathways defined unique SHH subpopulations, and made up a distinct shell-like structure of sulphur-containing species, comprising a combination of small leucine-rich proteoglycans (SLRPs) including the collagen organiser lumican. In contrast, the Group 3 tumour model was characterized by multiple subpopulations with greatly enhanced oxidative phosphorylation and tricarboxylic acid (TCA) cycle activity. Extensive TCA cycle metabolite measurements revealed very high levels of succinate and fumarate with malate levels almost undetectable particularly in Group 3 tumour models. In patients, high fumarate levels (NMR spectroscopy) alongside activated stress response pathways and high Nuclear Factor Erythroid 2-Related Factor 2 (NRF2; gene expression analyses) were associated with poorer survival. Based on these findings we predicted and confirmed that NRF2 inhibition increased sensitivity to vincristine in a long-term 3D drug treatment assay of Group 3 MB. Thus, by combining scRNAseq and 3D OrbiSIMS in a relevant model system we were able to define MB subgroup heterogeneity at the single cell level and elucidate new druggable biomarkers for aggressive Group 3 and low-risk SHH MB.
TL;DR: In this paper , a series of 8 GB and 14 LGG with FGFR3:TACC3 fusion was reported to better characterize them and search for prognostic factors was done by the Kaplan-Meir method.
Abstract: Abstract Background Gliomas with FGFR3::TACC3 fusion mainly occur in adults, display pathological features of glioblastomas (GB) and are usually classified as glioblastoma, IDH -wildtype. However, cases demonstrating pathological features of low-grade glioma (LGG) lead to difficulties in classification and clinical management. We report a series of 8 GB and 14 LGG with FGFR3:TACC3 fusion in order to better characterize them. Methods Centralized pathological examination, search for TERT promoter mutation and DNA-methylation profiling were performed in all cases. Search for prognostic factors was done by the Kaplan–Meir method. Results TERT promoter mutation was recorded in all GB and 6/14 LGG. Among the 7 cases with a methylation score > 0.9 in the classifier (v12.5), 2 were classified as glioblastoma, 4 as ganglioglioma (GG) and 1 as dysembryoplastic neuroepithelial tumor (DNET). t-SNE analysis showed that the 22 cases clustered into three groups: one included 12 cases close to glioblastoma, IDH -wildtype methylation class (MC), 5 cases each clustered with GG or DNET MC but none with PLNTY MC. Unsupervised clustering analysis revealed four groups, two of them being clearly distinct: 5 cases shared age (< 40), pathological features of LGG, lack of TERT promoter mutation, FGFR3 (Exon 17):: TACC3 (Exon 10) fusion type and LGG MC. In contrast, 4 cases shared age (> 40), pathological features of glioblastoma, and were TERT -mutated. Relevant factors associated with a better prognosis were age < 40 and lack of TERT promoter mutation. Conclusion Among gliomas with FGFR3::TACC3 fusion, age, TERT promoter mutation, pathological features, DNA-methylation profiling and fusion subtype are of interest to determine patients’ risk.
TL;DR: In this paper , the authors performed a genetic analysis of epileptogenic brain malformed lesions from 64 patients with focal cortical dysplasia, hemimegalencephy, brain tumors, or hippocampal sclerosis.
Abstract: Focal cortical dysplasia is the most common malformation during cortical development, sometimes excised by epilepsy surgery and often caused by somatic variants of the mTOR pathway genes. In this study, we performed a genetic analysis of epileptogenic brain malformed lesions from 64 patients with focal cortical dysplasia, hemimegalencephy, brain tumors, or hippocampal sclerosis. Targeted sequencing, whole-exome sequencing, and single nucleotide polymorphism microarray detected four germline and 35 somatic variants, comprising three copy number variants and 36 single nucleotide variants and indels in 37 patients. One of the somatic variants in focal cortical dysplasia type IIB was an in-frame deletion in MTOR, in which only gain-of-function missense variants have been reported. In focal cortical dysplasia type I, somatic variants of MAP2K1 and PTPN11 involved in the RAS/MAPK pathway were detected. The in-frame deletions of MTOR and MAP2K1 in this study resulted in the activation of the mTOR pathway in transiently transfected cells. In addition, the PTPN11 missense variant tended to elongate activation of the mTOR or RAS/MAPK pathway, depending on culture conditions. We demonstrate that epileptogenic brain malformed lesions except for focal cortical dysplasia type II arose from somatic variants of diverse genes but were eventually linked to the mTOR pathway.
TL;DR: In this article , the functional impact of histopathological alterations in the murine P301S model of tauopathy was investigated, and a decrease in visual acuity was detected at 6 months, the onset of disease.
Abstract: Tauopathies, including Alzheimer's disease, are characterized by retinal ganglion cell loss associated with amyloid and phosphorylated tau deposits. We investigated the functional impact of these histopathological alterations in the murine P301S model of tauopathy. Visual impairments were demonstrated by a decrease in visual acuity already detectable at 6 months, the onset of disease. Visual signals to the cortex and retina were delayed at 6 and 9 months, respectively. Surprisingly, the retinal output signal was delayed at the light onset and advanced at the light offset. This antagonistic effect, due to a dysfunction of the cone photoreceptor synapse, was associated with changes in the expression of the vesicular glutamate transporter and a microglial reaction. This dysfunction of retinal glutamatergic synapses suggests a novel interpretation for visual deficits in tauopathies and it highlights the potential value of the retina for the diagnostic assessment and the evaluation of therapies in Alzheimer's disease and other tauopathies.
TL;DR: In this article , a review of new immunotherapy strategies in association with the knowledge of the immune micro-environment is presented, where the authors address the advances in the design of neoantigen vaccines and possible new immune modulators.
Abstract: Glial-origin brain tumors, including glioblastomas (GBM), have one of the worst prognoses due to their rapid and fatal progression. From an oncological point of view, advances in complete surgical resection fail to eliminate the entire tumor and the remaining cells allow a rapid recurrence, which does not respond to traditional therapeutic treatments. Here, we have reviewed new immunotherapy strategies in association with the knowledge of the immune micro-environment. To understand the best lines for the future, we address the advances in the design of neoantigen vaccines and possible new immune modulators. Recently, the efficacy and availability of vaccine development with different formulations, especially liposome plus mRNA vaccines, has been observed. We believe that the application of new strategies used with mRNA vaccines in combination with personalized medicine (guided by different omic's strategies) could give good results in glioma therapy. In addition, a large part of the possible advances in new immunotherapy strategies focused on GBM may be key improving current therapies of immune checkpoint inhibitors (ICI), given the fact that this type of tumor has been highly refractory to ICI.
TL;DR: In this article , the authors explored the molecular alterations of these metastatic lesions and their respective intracranial tumor manifestations, and molecular analyses confirmed true metastatic disease in four meningioma patients.
Abstract: Abstract Extracranial metastases of intracranial meningiomas are rare. Little is known about the mutational pattern of these tumors and their metastatic seeding. Here, we retrospectively explored the molecular alterations of these metastatic lesions and their respective intracranial tumor manifestations. Histology and genome sequencing were performed in intracranial meningiomas and their extracranial metastatic lesions operated upon between 2002 and 2021. Next-generation DNA/RNA sequencing (NGS) and methylome analysis were performed to determine molecular alterations. We analyzed the tumors of five patients with clinically suspected metastases of a meningioma using methylome analysis and next generation panel sequencing of the primary tumors as well as the metastatic lesions. Metastases were found in the spinal cord and one in the lung. In four of these patients, molecular analyses confirmed metastatic disease, while the fifth patient was found to harbor two molecularly distinct meningiomas. On pathological assessment, the primary lesions ranged from CNS WHO grades 1 to 3 (integrated molecular-morphologic meningioma classification scores 2 to 6). Of the four true metastatic cases, three out of the four metastasizing tumors harbored alterations in the BAP1 gene, comprising a stop-mutation combined with copy-number loss (WHO grade 1), copy number loss (WHO grade 3) and a frameshift mutation (WHO grade 2). Furthermore, the latter was confirmed to harbor a BAP1 tumor predisposition syndrome. The fourth metastasizing tumor had copy-number losses in NF2 and PTEN. Only one of four showed CDKN2A homozygous deletion; none showed TERT promotor mutation. Our results molecularly confirm true metastatic disease in four meningioma patients. BAP1 gene alterations were the most frequent. Larger cohorts, most likely from multicenter studies are necessary to evaluate the role of BAP-1 alterations to further understand the metastatic spread in meningiomas. for metastatic spread and might indicate patients at risk for metastatic spread. Further explorations within larger cohorts are necessary to validate these findings which might influence the clinical management in the future.
TL;DR: In this article , translatomes of neuronal cell types from both regions in a new HD mouse model were analyzed and the strongest response with 626 differentially expressed genes in glutamatergic neurons of the cerebellum, a population consisting primarily of granule cells commonly considered disease resistant.
Abstract: Abstract Although Huntington’s disease (HD) is classically defined by the selective vulnerability of striatal projection neurons, there is increasing evidence that cerebellar degeneration modulates clinical symptoms. However, little is known about cell type-specific responses of cerebellar neurons in HD. To dissect early disease mechanisms in the cerebellum and cerebrum, we analyzed translatomes of neuronal cell types from both regions in a new HD mouse model. For this, HdhQ200 knock-in mice were backcrossed with the calm 129S4 strain, to constrain experimental noise caused by variable hyperactivity of mice in a C57BL/6 background. Behavioral and neuropathological characterization showed that these S4-HdhQ200 mice had very mild behavioral abnormalities starting around 12 months of age that remained mild up to 18 months. By 9 months, we observed abundant Huntingtin-positive neuronal intranuclear inclusions (NIIs) in the striatum and cerebellum. The translatome analysis of GABAergic cells of the cerebrum further confirmed changes typical of HD-induced striatal pathology. Surprisingly, we observed the strongest response with 626 differentially expressed genes in glutamatergic neurons of the cerebellum, a population consisting primarily of granule cells, commonly considered disease resistant. Our findings suggest vesicular fusion and exocytosis, as well as differentiation-related pathways are affected in these neurons. Furthermore, increased expression of cyclin D1 ( Ccnd1 ) in the granular layer and upregulated expression of polycomb group complex protein genes and cell cycle regulators Cbx2, Cbx4 and Cbx8 point to a putative role of aberrant cell cycle regulation in cerebellar granule cells in early disease.
TL;DR: In this paper , a comprehensive lipidomic analysis, enzyme activity assays, and western blotting on grey and white matter samples from the heavily-affected frontal lobe and less-affected parietal lobe of FTD- C9orf7 2.
Abstract: Abstract Heterozygous mutations in the GRN gene and hexanucleotide repeat expansions in C9orf72 are the two most common genetic causes of Frontotemporal Dementia (FTD) with TDP-43 protein inclusions. The triggers for neurodegeneration in FTD with GRN (FTD- GRN ) or C9orf72 (FTD- C9orf72 ) gene abnormalities are unknown, although evidence from mouse and cell culture models suggests that GRN mutations disrupt lysosomal lipid catabolism. To determine how brain lipid metabolism is affected in familial FTD with TDP-43 inclusions, and how this is related to myelin and lysosomal markers, we undertook comprehensive lipidomic analysis, enzyme activity assays, and western blotting on grey and white matter samples from the heavily-affected frontal lobe and less-affected parietal lobe of FTD- GRN cases, FTD- C9orf72 cases, and age-matched neurologically-normal controls. Substantial loss of myelin-enriched sphingolipids (sulfatide, galactosylceramide, sphingomyelin) and myelin proteins was observed in frontal white matter of FTD- GRN cases. A less-pronounced, yet statistically significant, loss of sphingolipids was also observed in FTD- C9orf7 2. FTD- GRN was distinguished from FTD- C9orf72 and control cases by increased acylcarnitines in frontal grey matter and marked accumulation of cholesterol esters in both frontal and parietal white matter, indicative of myelin break-down. Both FTD- GRN and FTD- C9orf72 cases showed significantly increased lysosomal and phagocytic protein markers, however galactocerebrosidase activity, required for lysosomal catabolism of galactosylceramide and sulfatide, was selectively increased in FTD- GRN . We conclude that both C9orf72 and GRN mutations are associated with disrupted lysosomal homeostasis and white matter lipid loss, but GRN mutations cause a more pronounced disruption to myelin lipid metabolism. Our findings support the hypothesis that hyperactive myelin lipid catabolism is a driver of gliosis and neurodegeneration in FTD- GRN . Since FTD- GRN is associated with white matter hyperintensities by MRI, our data provides important biochemical evidence supporting the use of MRI measures of white matter integrity in the diagnosis and management of FTD.
TL;DR: In this paper , the authors performed a detailed quantitative investigation of reactive astrocytes in post-mortem neocortical tissues from thirteen patients with Alpers' syndrome, eight neurologically normal controls and five sudden unexpected death in epilepsy (SUDEP) patients, to control for generalised epilepsy-associated asthma-associated pathology.
Abstract: Abstract Refractory epilepsy is the main neurological manifestation of Alpers’ syndrome, a severe childhood-onset mitochondrial disease caused by bi-allelic pathogenic variants in the mitochondrial DNA (mtDNA) polymerase gamma gene ( POLG ). The pathophysiological mechanisms underpinning neuronal hyperexcitabilty leading to seizures in Alpers’ syndrome remain unknown. However, pathological changes to reactive astrocytes are hypothesised to exacerbate neural dysfunction and seizure-associated cortical activity in POLG-related disease. Therefore, we sought to phenotypically characterise astrocytic pathology in Alpers’ syndrome. We performed a detailed quantitative investigation of reactive astrocytes in post-mortem neocortical tissues from thirteen patients with Alpers’ syndrome, eight neurologically normal controls and five sudden unexpected death in epilepsy (SUDEP) patients, to control for generalised epilepsy-associated astrocytic pathology. Immunohistochemistry to identify glial fibrillary acidic protein (GFAP)-reactive astrocytes revealed striking reactive astrogliosis localised to the primary visual cortex of Alpers’ syndrome tissues, characterised by abnormal-appearing hypertrophic astrocytes. Phenotypic characterisation of individual GFAP-reactive astrocytes demonstrated decreased abundance of mitochondrial oxidative phosphorylation (OXPHOS) proteins and altered expression of key astrocytic proteins including Kir4.1 (subunit of the inwardly rectifying K + ion channel), AQP4 (astrocytic water channel) and glutamine synthetase (enzyme that metabolises glutamate). These phenotypic astrocytic changes were typically different from the pathology observed in SUDEP tissues, suggesting alternative mechanisms of astrocytic dysfunction between these epilepsies. Crucially, our findings provide further evidence of occipital lobe involvement in Alpers’ syndrome and support the involvement of reactive astrocytes in the pathogenesis of POLG-related disease.
TL;DR: In this paper , a sonic hedgehog (SHH) group-specific circular RNAs (circRNAs) was identified as group specific with its expression confirmed by RNA-FISH analysis in clinical tissue samples.
Abstract: Abstract Medulloblastoma (MB) develops through various genetic, epigenetic, and non-coding (nc) RNA-related mechanisms, but the roles played by ncRNAs, particularly circular RNAs (circRNAs), remain poorly defined. CircRNAs are increasingly recognized as stable non-coding RNA therapeutic targets in many cancers, but little is known about their function in MBs. To determine medulloblastoma subgroup-specific circRNAs, publicly available RNA sequencing (RNA-seq) data from 175 MB patients were interrogated to identify circRNAs that differentiate between MB subgroups. circ_63706 was identified as sonic hedgehog (SHH) group-specific, with its expression confirmed by RNA-FISH analysis in clinical tissue samples. The oncogenic function of circ_63706 was characterized in vitro and in vivo. Further, circ_63706 -depleted cells were subjected to RNA-seq and lipid profiling to identify its molecular function. Finally, we mapped the circ_63706 secondary structure using an advanced random forest classification model and modeled a 3D structure to identify its interacting miRNA partner molecules. Circ_63706 regulates independently of the host coding gene pericentrin ( PCNT ), and its expression is specific to the SHH subgroup. circ_63706 -deleted cells implanted into mice produced smaller tumors, and mice lived longer than parental cell implants. At the molecular level, circ_63706 -deleted cells elevated total ceramide and oxidized lipids and reduced total triglyceride. Our study implicates a novel oncogenic circular RNA in the SHH medulloblastoma subgroup and establishes its molecular function and potential as a future therapeutic target.
TL;DR: Parkinsufficiency in mice was found to increase the ratio of reduced glutathione (GSH) to oxidized GSSG (GSSG) in murine brain, PRKNlinked human cortex and several cell models as mentioned in this paper .
Abstract: We recently discovered that the expression of PRKN, a young-onset Parkinson disease-linked gene, confers redox homeostasis. To further examine the protective effects of parkin in an oxidative stress model, we first combined the loss of prkn with Sod2 haploinsufficiency in mice. Although adult prkn-/-//Sod2± animals did not develop dopamine cell loss in the S. nigra, they had more reactive oxidative species and a higher concentration of carbonylated proteins in the brain; bi-genic mice also showed a trend for more nitrotyrosinated proteins. Because these redox changes were seen in the cytosol rather than mitochondria, we next explored the thiol network in the context of PRKN expression. We detected a parkin deficiency-associated increase in the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) in murine brain, PRKN-linked human cortex and several cell models. This shift resulted from enhanced recycling of GSSG back to GSH via upregulated glutathione reductase activity; it also correlated with altered activities of redox-sensitive enzymes in mitochondria isolated from mouse brain (e.g., aconitase-2; creatine kinase). Intriguingly, human parkin itself showed glutathione-recycling activity in vitro and in cells: For each GSSG dipeptide encountered, parkin regenerated one GSH molecule and was S-glutathionylated by the other (GSSG + P-SH [Formula: see text] GSH + P-S-SG), including at cysteines 59, 95 and 377. Moreover, parkin's S-glutathionylation was reversible by glutaredoxin activity. In summary, we found that PRKN gene expression contributes to the network of available thiols in the cell, including by parkin's participation in glutathione recycling, which involves a reversible, posttranslational modification at select cysteines. Further, parkin's impact on redox homeostasis in the cytosol can affect enzyme activities elsewhere, such as in mitochondria. We posit that antioxidant functions of parkin may explain many of its previously described, protective effects in vertebrates and invertebrates that are unrelated to E3 ligase activity.
TL;DR: In this paper , the authors used RNA-sequencing data (bulk, single cell, and single nucleus) and antibody labeling in highly preserved enucleated human eyes to identify expression of NAD synthesizing enzyme machinery.
Abstract: Glaucoma is the leading cause of irreversible blindness and is a major health and economic burden. Current treatments do not address the neurodegenerative component of glaucoma. In animal models of glaucoma, the capacity to maintain retinal nicotinamide adenine dinucleotide (NAD) pools declines early during disease pathogenesis. Treatment with nicotinamide, an NAD precursor through the NAD salvage pathway, robustly protects against neurodegeneration in a number of glaucoma models and improves vision in existing glaucoma patients. However, it remains unknown in humans what retinal cell types are able to process nicotinamide to NAD and how these are affected in glaucoma. To address this, we utilized publicly available RNA-sequencing data (bulk, single cell, and single nucleus) and antibody labelling in highly preserved enucleated human eyes to identify expression of NAD synthesizing enzyme machinery. This identifies that the neural retina favors expression of the NAD salvage pathway, and that retinal ganglion cells are particularly enriched for these enzymes. NMNAT2, a key terminal enzyme in the salvage pathway, is predominantly expressed in retinal ganglion cell relevant layers of the retina and declines in glaucoma. These findings suggest that human retinal ganglion cells can directly utilize nicotinamide and could maintain a capacity to do so in glaucoma, showing promise for ongoing clinical trials.
TL;DR: In this article , the authors describe an 87-year-old woman with a 7-year history of cognitive decline, hand tremor and gait problems, who was thought to have Alzheimer's disease.
Abstract: Frontotemporal lobar degeneration (FTLD) is a group of disorders characterized by degeneration of the frontal and temporal lobes, leading to progressive decline in language, behavior, and motor function. FTLD can be further subdivided into three main subtypes, FTLD-tau, FTLD-TDP and FTLD-FUS based which of the three major proteins - tau, TDP-43 or FUS - forms pathological inclusions in neurons and glia. In this report, we describe an 87-year-old woman with a 7-year history of cognitive decline, hand tremor and gait problems, who was thought to have Alzheimer's disease. At autopsy, histopathological analysis revealed severe neuronal loss, gliosis and spongiosis in the medial temporal lobe, orbitofrontal cortex, cingulate gyrus, amygdala, basal forebrain, nucleus accumbens, caudate nucleus and anteromedial thalamus. Tau immunohistochemistry showed numerous argyrophilic grains, pretangles, thorn-shaped astrocytes, and ballooned neurons in the amygdala, hippocampus, parahippocampal gyrus, anteromedial thalamus, insular cortex, superior temporal gyrus and cingulate gyrus, consistent with diffuse argyrophilic grain disease (AGD). TDP-43 pathology in the form of small, dense, rounded neuronal cytoplasmic inclusion with few short dystrophic neurites was observed in the limbic regions, superior temporal gyrus, striatum and midbrain. No neuronal intranuclear inclusion was observed. Additionally, FUS-positive inclusions were observed in the dentate gyrus. Compact, eosinophilic intranuclear inclusions, so-called "cherry spots," that were visible on histologic stains were immunopositive for α-internexin. Taken together, the patient had a mixed neurodegenerative disease with features of diffuse AGD, TDP-43 proteinopathy and neuronal intermediate filament inclusion disease. She met criteria for three subtypes of FTLD: FTLD-tau, FTLD-TDP and FTLD-FUS. Her amnestic symptoms that were suggestive of Alzheimer's type dementia are best explained by diffuse AGD and medial temporal TDP-43 proteinopathy, and her motor symptoms were likely explained by neuronal loss and gliosis due to tau pathology in the substantia nigra. This case underscores the importance of considering multiple proteinopathies in the diagnosis of neurodegenerative diseases.
TL;DR: In this article , the authors examined NRG1 mRNA and protein expression levels in human and mouse SMA tissues and observed reduced expression in SMA spinal cord and in ventral, but not dorsal root axons.
Abstract: Abstract Intercellular communication between axons and Schwann cells is critical for attaining the complex morphological steps necessary for axon maturation. In the early onset motor neuron disease spinal muscular atrophy (SMA), many motor axons are not ensheathed by Schwann cells nor grow sufficiently in radial diameter to become myelinated. These developmentally arrested motor axons are dysfunctional and vulnerable to rapid degeneration, limiting efficacy of current SMA therapeutics. We hypothesized that accelerating SMA motor axon maturation would improve their function and reduce disease features. A principle regulator of peripheral axon development is neuregulin 1 type III (NRG1-III). Expressed on axon surfaces, it interacts with Schwann cell receptors to mediate axon ensheathment and myelination. We examined NRG1 mRNA and protein expression levels in human and mouse SMA tissues and observed reduced expression in SMA spinal cord and in ventral, but not dorsal root axons. To determine the impact of neuronal NRG1-III overexpression on SMA motor axon development, we bred NRG1-III overexpressing mice to SMA∆7 mice. Neonatally, elevated NRG1-III expression increased SMA ventral root size as well as axon segregation, diameter, and myelination resulting in improved motor axon conduction velocities. NRG1-III was not able to prevent distal axonal degeneration nor improve axon electrophysiology, motor behavior, or survival of older mice. Together these findings demonstrate that early SMA motor axon developmental impairments can be ameliorated by a molecular strategy independent of SMN replacement providing hope for future SMA combinatorial therapeutic approaches.
TL;DR: In this article , a 51-year-old woman with unremarkable family history presented abruptly with aphasia and right hemiparesis. A cerebral left lobar haemorrhagic stroke was documented by neuroimaging.
Abstract: Cerebral amyloid angiopathy (CAA) is a small vessel disease, causing spontaneous intracerebral hemorrhage (ICH) in the elderly. It is strongly associated with Alzheimer disease (AD), as most CAA patients show deposition of Aβ-i.e. the basic component of parenchymal Alzheimer amyloid deposits-in the cerebral vessels. Iatrogenic early-onset CAA has been recently identified in patients with a history of traumatic brain injury or other cerebral as well as extra-cerebral lesions that led to neurosurgery or other medical procedures as intravascular embolization by cadaveric dura mater extracts many years before the first ICH event. In those patients, a transmission of Aβ seeds from neurosurgical instruments or from cadaveric dura mater exposure was suggested. We report a 51-year-old woman with unremarkable family history who presented abruptly with aphasia and right hemiparesis. A cerebral left lobar haemorrhagic stroke was documented by neuroimaging. Accurate anamnesis revealed a neurosurgical procedure with cadaveric dura mater graft at the age of 2 years for an arachnoid cyst. The neuropathological examination of the cerebral parietal biopsy showed severe amyloid angiopathy in many leptomeningeal and cortical vessels, as well as abundant parenchymal Aβ deposits, neurofibrillary tangles and neuropil threads. The mechanism involved in the human-to-human transmission of the Aβ proteinopathy remains to be clarified. In our patient the cadaver derived dura used for grafting is a very strong candidate as the source of the transmission. A systematic monitoring of individuals who have had neurosurgical procedures in early life, especially those involving cadaveric dural grafts, is required to determine the ratio of those affected by CAA many years later and unaffected. Moreover, our report confirms that in addition to vascular and parenchymal Aβ pathology, neurofibrillary changes indistinguishable from AD may develop in specific conditions with long latency period from the neurosurgical or embolization procedure.
TL;DR: In this paper , the authors examined synapses with a focus on mitochondrial deficits in presynaptic axonal terminals and dendritic spines in cortical biopsy samples from clinically diagnosed AD and age-matched non-AD control patients.
Abstract: Loss of synapses is the most robust pathological correlate of Alzheimer's disease (AD)-associated cognitive deficits, although the underlying mechanism remains incompletely understood. Synaptic terminals have abundant mitochondria which play an indispensable role in synaptic function through ATP provision and calcium buffering. Mitochondrial dysfunction is an early and prominent feature in AD which could contribute to synaptic deficits. Here, using electron microscopy, we examined synapses with a focus on mitochondrial deficits in presynaptic axonal terminals and dendritic spines in cortical biopsy samples from clinically diagnosed AD and age-matched non-AD control patients. Synaptic vesicle density within the presynaptic axon terminals was significantly decreased in AD cases which appeared largely due to significantly decreased reserve pool, but there were significantly more presynaptic axons containing enlarged synaptic vesicles or dense core vesicles in AD. Importantly, there was reduced number of mitochondria along with significantly increased damaged mitochondria in the presynapse of AD which correlated with changes in SV density. Mitochondria in the post-synaptic dendritic spines were also enlarged and damaged in the AD biopsy samples. This study provided evidence of presynaptic vesicle loss as synaptic deficits in AD and suggested that mitochondrial dysfunction in both pre- and post-synaptic compartments contribute to synaptic deficits in AD.
TL;DR: Wang et al. as mentioned in this paper described a patient with a five-year history of Richardson syndrome and a family history of PSP in her mother and sister, and concluded that this patient had an unclassified tauopathy and features of both progressive supranuclear palsy and corticobasal degeneration.
Abstract: Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are distinct clinicopathological subtypes of frontotemporal lobar degeneration. They both have atypical parkinsonism, and they usually have distinct clinical features. The most common clinical presentation of PSP is Richardson syndrome, and the most common presentation of CBD is corticobasal syndrome. In this report, we describe a patient with a five-year history of Richardson syndrome and a family history of PSP in her mother and sister. A tau PET scan (18F-APN-1607) revealed low-to-moderate uptake in the substantia nigra, globus pallidus, thalamus and posterior cortical areas, including temporal, parietal and occipital cortices. Neuropathological evaluation revealed widespread neuronal and glial tau pathology in cortical and subcortical structures, including tufted astrocytes in the motor cortex, striatum and midbrain tegmentum. The subthalamic nucleus had mild-to-moderate neuronal loss with globose neurofibrillary tangles, consistent with PSP. On the other hand, there were also astrocytic plaques, a pathological hallmark of CBD, in the neocortex and striatum. To further characterize the mixed pathology, we applied two machine learning-based diagnostic pipelines. These models suggested diagnoses of PSP and CBD depending on the brain region - PSP in the motor cortex and superior frontal gyrus and CBD in caudate nucleus. Western blots of insoluble tau from motor cortex showed a banding pattern consistent with mixed features of PSP and CBD, whereas tau from the superior frontal gyrus showed a pattern consistent with CBD. Real-time quaking-induced conversion (RT-QuIC) using brain homogenates from the motor cortex and superior frontal gyrus showed ThT maxima consistent with PSP, while reaction kinetics were consistent with CBD. There were no pathogenic variants in MAPT with whole genome sequencing. We conclude that this patient had an unclassified tauopathy and features of both PSP and CBD. The different pathologies in specific brain regions suggests caution in diagnosis of tauopathies with limited sampling.