Brain Pathology最新文献

Spinal muscular atrophy (SMA), a leading genetic cause of infant mortality worldwide, is caused by reduced levels of the ubiquitous survival motor neuron (SMN) protein in SMA patients. Despite significant advancement in recent research and clinical treatments, the cellular pathologies that underlie SMA disease manifestations are not well characterized beyond those of spinal motor neurons (MNs). We previously reported cerebellar abnormalities in an SMA mouse model at the late stage of the disease, including volumetric deficits and lobule-selective structural changes with Purkinje cell degeneration, with colocalized astrocytic reactivity. However, when these cerebellar defects arise and whether they are a consequence of MN degeneration remain unknown. We used magnetic resonance imaging, immunohistochemistry, and electrophysiology to characterize cerebellar pathology in early-stage symptomatic SMNΔ7 mice and late-stage SMA mice with transgenic rescue of SMN in MNs. We found disproportionate structural and lobule-specific surface area deficits, as well as abnormal functional properties in the cerebella of early symptomatic SMA mice, suggesting that cerebellar pathologies may be a primary contributor to murine SMA phenotypes. Moreover, cerebellar pathologies were not ameliorated in SMA mice with MN rescue, suggesting that cerebellar neurons are independently vulnerable to reduced SMN expression. Overall, our study shows that cerebellar defects are a primary pathology in SMA mouse models and that therapies targeting cerebellar neurons in SMA patients may be needed for optimal treatment outcomes.

Since the 2016 update of the WHO Classification of Tumors of the Central Nervous System, omics data have been officially integrated into the diagnostic process for glioblastoma, the most prevalent and aggressive primary malignant brain tumor in adults. This review will examine the current and future integration of omics data in both the diagnosis and therapy of glioblastomas. The current clinical use of omics data primarily focuses on genomics for determining the IDH- and H3-wildtype status of the tumor, and on epigenomics, such as assessing MGMT promoter methylation status as a prognostic and predictive biomarker. However, it can be anticipated that the usage and importance of omics data will likely increase in the future. This work highlights how omics technologies have significantly enhanced our understanding of glioblastoma, particularly of its extensive heterogeneity. This enhanced understanding has not only improved diagnostic accuracy but has also facilitated the identification of new predictive and/or prognostic biomarkers. It is likely that the ongoing integration of omics data will transform many aspects of the diagnostic process, including sample acquisition. Additionally, omics data will be integrated into future glioblastoma treatment procedures, with possible applications ranging from identifying potential therapeutic targets to selecting individual treatment plans. The implications of the ongoing integration of omics data for clinical routine, future classification systems, and trial design are also discussed in this review, outlining the pivotal role omics data play in shaping future glioblastoma diagnosis and treatment.

Synucleinopathies are a group of neurodegenerative diseases characterized by the deposition of misfolded α-synuclein (αSyn), predominantly in oligodendrocytes in multiple system atrophy (MSA) and in neurons in Lewy body diseases (LBD). The contribution of αSyn cytopathologies to the pathogenesis of these diseases is underappreciated. Seed amplification assays of MSA and LBD brains have revealed striking differences in αSyn seeding between regions and cases. Therefore, our aim was to evaluate whether different brain regions containing distinct αSyn cytopathologies contribute to different seeding characteristics. We collected 2-mm micro-punches of regions in MSA (n = 10) and LBD (n = 15) cases from formalin-fixed paraffin-embedded tissues. We performed double immuno-labeling for disease-associated αSyn and cellular markers on tissue microarrays, evaluated co-deposition of other neurodegenerative disease-related proteins and, from the same micro-punched samples, we analyzed αSyn seeding. Based on these variables, machine learning algorithms were used to reduce dimensionality of the dataset and cluster the regions in MSA and LBD cases, revealing that different compositions of αSyn cytopathologies influence αSyn seeding patterns. Our results support the notion of different cellular processing of αSyn and its contribution to the variability in seeding. This has implications for understanding disease progression, interpretation of seed amplification assays, and opens avenues for the development of cell type-specific antibodies against αSyn.

A key role for inflammation in amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) has been identified. It is vital to assess which central nervous system structures are most affected and which inflammatory processes are responsible in humans. The inflammatory transcriptome was characterized in the cervical spinal cord and motor cortex in post-mortem frozen and formalin-fixed paraffin-embedded specimens from human sporadic ALS/MND and control cases using the nCounter® Neuroinflammation Panel. Archival data were reanalyzed and compared with the nCounter data. Immunohistochemistry was used to examine the inflammatory response in the spinal cord and motor cortex and validate changes found during transcriptomic analyses. In the spinal cord, marked inflammation was observed, while less inflammation was detected in the motor cortex. Examination of differentially expressed genes in the spinal cord highlighted TREM2, TYROBP, APOE, and CD163, as well as phagocytic pathways. In sporadic ALS/MND spinal cord, significant microglial reactivity and involvement of TREM2, ApoE (encoded by APOE), and TYROBP were confirmed, suggesting the involvement of the disease-associated microglial (DAM) phenotype. The corticospinal tracts showed greater inflammation than the ventral horns. The precentral gyrus of ALS/MND again showed less immune reactivity to disease when compared to controls. Finally, in the largest cohort assessed to date, we demonstrate an association between the APOE variant and ALS/MND risk, age of onset, and survival. We find confirmed associations between APOE ε3/ε3 and disease and between ε2/ε2 and absence of disease. Further, ε4/ε4 appears to be associated with earlier disease onset and a more aggressive course. We conclude that while there is widespread inflammation in the CNS in sporadic ALS/MND, this is more marked in the spinal cord, especially the corticospinal tract. The specific markers stress the DAM phenotype as having a key role together with a possible influx of somatic macrophages. In addition, APOE function and genotype may be relevant in ALS/MND.

Emerging studies underscore the pivotal role of glymphatic system (GS) dysfunction in the pathogenesis of cerebral edema following brain injury. The transient receptor potential vanilloid 4 (TRPV4) channels have been implicated in modulating the polarization of aquaporin-4 (AQP4), a key protein involved in GS function. This study investigates the potential of targeting TRPV4 to alleviate GS dysfunction and reduce cerebral edema following ischemic stroke. TRPV4 inhibitor HC067047 or a vehicle was administered via lateral ventricle cannulation in a mouse model of middle cerebral artery occlusion and reperfusion (MCAO/R). The function of the GS was assessed through tracer injection experiments, including in vivo transcranial imaging, ex vivo brain tissue and section analysis, and fluorescence retention in deep cervical lymph nodes (dCLNs). Cerebral edema was quantified using magnetic resonance imaging. AQP4 polarization and β-dystroglycan (β-DG) expression were evaluated by immunofluorescence. Western blotting was employed to measure protein levels of β-DG, matrix metalloproteinase-9 (MMP9), and Ras homolog family member A (RhoA). Long-term neurological outcomes were assessed via behavioral testing. MCAO/R mice exhibited significant GS dysfunction, cerebral edema, and disrupted AQP4 polarization. Additionally, β-DG expression was markedly reduced, while TRPV4 expression was elevated in the ischemic penumbra. Western blotting revealed increased expression of MMP9 and RhoA. The inhibition of TRPV4 by HC067047 significantly improved GS function, reduced cerebral edema, and enhanced neurological recovery. Mechanistically, HC067047 partially restored AQP4 polarization, upregulated β-DG expression, and suppressed the expression of MMP9 and RhoA. These findings highlight the therapeutic potential of TRPV4 inhibition in ischemic stroke by restoring GS function, mitigating cerebral edema, and promoting neurological recovery, thereby positioning TRPV4 as a promising target for future interventions.

Glioblastomas represent the most common and lethal primary brain tumors in the world. Despite therapeutic advances during the last two decades, patient prognosis remains very poor. The Hippo signaling pathway effectors YAP/TAZ-TEADs play a crucial role in tumor progression and represent promising therapeutic targets in gliomas. In this study, we identified and investigated the clinical and biological significance of TEAD transcription factors. Through comprehensive analyses of TCGA glioma data and patient samples, we identified TEAD3-4 transcription factors as robust prognostic markers of patient outcome. Using up to five different patient-derived glioblastoma stem cell cultures, we confirmed the preferential expression and activation of TEAD3-4 along with their transcriptional coactivators YAP/TAZ. Pharmacological inhibition of YAP/TAZ-TEAD interaction by Verteporfin significantly decreased tumor cell growth, whereas specific inhibition of TEAD3 did not impact cell proliferation but affected sterol/cholesterol biosynthetic and metabolic processes. This study contributes to a better understanding of the role of Hippo effectors in glioblastoma pathophysiology. These transcription factors, particularly TEAD3, could potentially serve as therapeutic targets, especially considering recent data on cholesterol homeostasis in glioblastomas.

Dysregulation of the complement system plays an important role in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD). In post-mortem AD brains, complement is deposited in and around amyloid plaques, and peri-plaque complement activation drives synapse loss in AD mouse models. Studies to date have focused on amyloid pathology; however, aggregated tau is also involved in neuronal loss in AD. Primary tauopathies are characterised by tau pathology in the absence of amyloid. The role of complement in human tauopathies remains largely unexplored. Here, we address this knowledge gap by assessing complement activation in human tauopathy brains using immunohistochemistry and well-characterised detection tools. Post-mortem pre-frontal cortex was obtained from three tauopathy subtypes, Pick's disease (PiD), globular glial tauopathy (GGT) and corticobasal degeneration (CBD) (3–5 cases each). C1q and the complement activation markers iC3b and terminal complement complex (TCC) were assessed by immunohistochemistry and were elevated in all tauopathy cases compared to controls, with C1q and C3b/iC3b deposition particularly prominent on neurons, demonstrating complement activation on these cells. TCC deposits were present on and adjacent neurons in all tauopathy brains examined and were significantly increased compared to controls in CBD and GGT. Uniquely in GGT, abundant deposition of C3b/iC3b on myelin was also observed, implicating complement in GGT-associated demyelination. To validate these findings, complement proteins (C1q, C3, factor B), regulators (factor I, clusterin) and activation products (Ba, C3b/iC3b, and TCC) were measured in brain homogenates by ELISA, revealing significant elevation in C3b/iC3b, Ba, and FI in CBD and GGT cases compared to controls. Together, our data demonstrate complement activation on and adjacent neurons in post-mortem brains from all tauopathy subtypes.