Acta Neuropathologica Communications最新文献

Intertumoral heterogeneity in glioblastoma-driven by both genomic and transcriptomic variation-complicates our understanding of how different tumor cell populations contribute to disease progression. Infiltrating tumor cells, which invade surrounding brain tissue and evade surgical resection, are thought to play a central role in recurrence. To address this, we aimed to characterize the gene expression profiles and cellular states of infiltrative tumor cells in glioblastoma. We performed high-plex spatial transcriptomics using the CosMx Spatial Molecular Imager (NanoString) on tumor tissue from eight glioblastoma patients. Formalin-fixed paraffin-embedded samples were selected to capture both the tumor core and invasive margin. A targeted panel of 1,000 genes enabled spatially resolved gene expression profiling at single-cell resolution, allowing precise identification and localization of malignant and non-malignant cell states. We show that malignant cells can be distinguished from non-malignant populations by using patient-specific clustering. Based on this annotation, we identified several known malignant states-including AC-, OPC-, NPC-, and MES-like cells-as well as a recently characterized glial-progenitor (GPC)-like state. This population co-expressed genes associated with both astrocytic and oligodendrocyte progenitor lineages and was found to be more proliferative than the traditional AC-like state. The GPC-like state was most enriched in the classical glioblastoma subtype and was strongly associated with EGFR amplification or mutation. Spatial analyses investigating malignant differences between tumor and infiltrated tissue showed heterogeneous infiltration patterns across patients. In the most extreme case, the dominant GPC-like population in the tumor core gave way to increased proportions of AC-like cells in infiltrated regions. Our study highlights diverging infiltration patterns across glioblastoma tumors, with indications of a GPC-like to AC-like transition occurring in classical-subtyped tumors. This shift is associated with a decrease in cell proliferation and may have implications for clinical treatment.

Recent RNA-sequencing studies have established a reactive molecular signature and highlighted substantial regional diversity of microglia, underscoring their involvement in neurodegenerative proteinopathies. However, the implications of these findings have not been fully elucidated at the protein expression level in neuropathological settings, especially when comparing different proteinopathies. Using FFPE tissue from postmortem human brains with neuropathologically confirmed sporadic Creutzfeldt-Jakob disease, subtype MM1 (n = 5, formic acid-treated tissue), Alzheimer's disease, Braak stage VI (n = 5), and control brains with no noteworthy pathological changes (n = 2), we (1) verify the reactive microglial signature at the protein expression level utilizing spatial protein profiling, (2) detect a disease-specific amoeboid IBA1+ cell subtype identified with digital morphological profiling, and (3) determine the correlation between identified microglia protein expression profiles and morphology within each and across all brain sample groups. As proof-of-concept, the protein expression and morphology profiling modalities can be bioinformatically integrated to quantify the reactivity of analyzed IBA1+ cells when comparing different neocortical layers (superficial grey matter, deep grey matter, and white matter) and frontal and occipital neocortex across the different diseases. We observed greater microglial reactivity in Creutzfeldt-Jakob disease compared to Alzheimer's disease, and more remarkably, greater reactivity in occipital cortex compared to frontal cortex across both diseases. Both profiling modalities additionally revealed consistent molecular and morphological differences between grey matter and white matter IBA1+ cells, with similar distributional changes observed in the layers across both diseases. This study refines the understanding of canonical, disease-specific, and brain regional features of reactive microglia in two different neurodegenerative proteinopathies and demonstrates the successful application of spatial probe-based protein profiling together with digital morphological profiling on long-term fixed FFPE and even formic acid-treated human brain tissue.

Loss of Cisd2, an iron-sulfur cluster transfer protein, results in type 2 Wolfram syndrome (WS2), a disorder associated with severe impacts on pancreatic β cell and neuronal functions. Cisd2 has been implicated in regulating intracellular Ca²⁺ signaling. However, the molecular basis and cellular consequences remain poorly understood. In this work, we demonstrate that Cisd2 intersects with intracellular Ca²⁺ dynamics at different levels, by interacting with the inositol-1,4,5-trisphosphate receptors and as a regulator of ER-mitochondria tethering. As such, loss of Cisd2 in HeLa cells results in reduced ER-mitochondrial Ca²⁺ transfer while only modestly impacting cytosolic Ca²⁺ signaling. In HeLa cells, Cisd2 deficiency promotes autophagic flux, yet has minimal impact on mitochondrial function. However, studying the impact of Cisd2 deficiency in human induced pluripotent stem cell -derived cortical neurons revealed a severe loss of glutamate-evoked Ca²⁺ responses in cytosol and associated uptake in mitochondria due to loss of ER-mitochondria contact sites. Correlating with the profound changes in cellular Ca²⁺ handling, mitochondrial function (oxygen consumption rate, ATP production, mitochondrial potential maintenance) declined severely, while autophagic flux was increased. Overall, these deficiencies further impact the resilience of Cisd2-deficient cortical neurons to cell stress as Cisd2-KO neurons were highly sensitive to staurosporine, an inducer of apoptosis. Overall, this work is one of the first to decipher the impact of Cisd2 on ER-mitochondria Ca²⁺ handling in a WS2 disease-relevant cell models, thereby revealing a unique dependence of neurons on Cisd2 for their mitochondrial health and cell stress resilience.

Previous studies have revealed four distinct epigenetic consensus pineoblastoma (PB) subtypes. The aim of this study was to confirm and further extend their respective genetic underpinnings. Cytogenetics of 83 PB were analyzed by high-resolution genome-wide molecular inversion probe analysis and methylation profiling. Seventy-nine cases were screened for mutations by next-generation DNA panel sequencing and for 25 samples mRNA expression was analyzed using NanoString. Additionally, 24 further pineal parenchymal tumors were analyzed. Clinical data of 63 patients was available. Our cohort consisted of 48 PB-miRNA1, 19 PB-miRNA2, 8 PB-MYC/FOXR2, and 8 PB-RB1 cases. PB-miRNA subtype tumors had characteristic alterations in microRNA-processing genes; DICER1 mutations (n = 19/64) and homozygous deletions of the DROSHA locus (n = 18/67) were most abundant, followed by DROSHA mutations (n = 12/64). Most frequent cytogenetic aberrations in PB-miRNA cases were chromosome 7 gains (n = 31/67) and chromosome 14 losses (n = 26/67, including 5 cases with copy-neutral LOH). The latter were significantly associated with DICER1 mutations (p < 0.001). OTX2 gain represented the most frequent alteration that occurred in 37/83 PB of all subtypes. In the PB-miRNA subtypes we identified cases with polyploid cytogenetics (n = 16/67). In contrast to previous publications, we did not find a difference in survival for the PB-miRNA subtypes, whereas PB-MYC/FOXR2 and PB-RB1 in infants showed a worse outcome. Epigenetically defined PB subtypes are characterized by distinct genetic events. Frequent gains of the oncogene OTX2 indicate a role in the pathogenesis of PB independent of its subtype.

Human chorionic gonadotropin (hCG) is a hormone that may be abnormally secreted in several tumour types, including intracranial germ cell tumours. In pineal region tumors, hCG is a key tumor marker. In fact, mild elevation typically suggests a germinoma with syncytiotrophoblastic cells, whereas a markedly elevated level indicates a choriocarcinoma or a mixed germ cell tumor with trophoblastic differentiation. While histopathological confirmation remains the diagnostic gold standard, the anatomical situation of the pineal gland makes biopsy very challenging. In certain situations, diagnosis may therefore rely on a constellation of clinical, radiological, and biochemical findings, including cerebrospinal fluid (CSF) β-hCG levels. However, the differential diagnosis of pineal region tumours includes other primary neoplasms of the pineal parenchyma, which differ markedly in both prognosis and therapeutic management. Here, we report two cases of pineoblastoma with unexpectedly elevated CSF β-hCG levels, which might have led to a misdiagnosis of intracranial germinoma. These cases highlight the need for the development of novel, non-invasive biomarkers to improve the diagnostic accuracy of intracranial tumours.

The presence of amyloid and tau pathologies is the pathological hallmark of Alzheimer's disease (AD). However, the presence of non-demented individuals with sufficient AD pathology indicates that AD-linked pathology does not always lead to dementia. The current view is that a non-demented (ND) individual with sufficient AD pathology represents an individual resilient to AD pathology. To gain insight about resilience to AD pathology, we examined the neuropathology in the brainstem monoaminergic (MAergic) neurons in the Nun Study participants with equally high Braak AD stage (V-VI) with dementia and without clinical dementia. Because MAergic pathology is thought to occur in response to cortical AD pathology, any differences in MAergic pathology between the AD and ND groups with similarly advanced AD pathology could reflect the resilience of MAergic neurons to cortical AD pathology. Examination of Locus Coeruleus (LC) and/or Raphe for the presence of tau pathology showed that, despite the similar forebrain pathology, relative levels of perikaryal and neuritic tau pathology were significantly lower in ND than in AD subjects. The ND subjects exhibit greater pathology than control subjects without AD pathology, indicating that cortical AD pathology does impact subcortical neurons in both AD and ND cases. Significantly, the extent of neurodegenerative pathology in LC and Raphe neurons correlated with cognitive performance in AD cases, while no such correlation was seen in ND cases. Our results show that while cortical AD pathology is associated with increased MAergic neuropathology, quantitative differences in the extent of MAergic pathology in the brainstem may reflect underlying resistance to AD pathology.