Correlative chemical imaging identifies amyloid peptide signatures of neuritic plaques and dystrophy in human sporadic Alzheimer's disease

OBJECTIVE: Alzheimer's disease (AD) is the most common neurodegenerative disease. The predominantly sporadic form of AD (sAD) is age-related, but the underlying pathogenic mechanisms remain not fully understood. Current efforts to combat the disease focus on the main pathological hallmarks, in particular beta-amyloid (Aβ) plaque pathology. According to the amyloid cascade hypothesis, Aβ is the critical early initiator of AD pathogenesis. Plaque pathology is very heterogeneous, where a subset of plaques, neuritic plaques, are considered most neurotoxic rendering their in depth characterization essential to understand Aβ pathogenicity. METHODS: To delineate the chemical traits specific to neuritic plaque types, we investigated senile Aβ pathology in post mortem human sporadic AD brain using advanced correlative biochemical imaging based on immunofluorescence microscopy and mass spectrometry imaging (MSI). RESULTS: Immunostaining-guided MSI identified distinct Aβ signatures of neuritic plaques characterized by increased Aβ 1-42(ox) and Aβ2-42. Moreover, correlation with a marker of dystrophy (reticulon 3, RTN3) identified key Aβ species that both delineate neuritic plaques and display association with neuritic dystrophy. CONCLUSION: Together these correlative imaging data shed light on the complex biochemical architecture of neuritic plaques and associated dystrophic neurites. These in turn are obvious targets for disease-modifying treatment strategies, as well as novel biomarkers of Aβ pathogenicity

Investigating New Applications of a Photoswitchable Fluorescent Norbornadiene as a Multifunctional Probe for Delineation of Amyloid Plaque Polymorphism

Amyloid beta (Aβ) plaques are a major pathological hallmark of Alzheimer’s disease (AD) and constitute of structurally heterogenic entities (polymorphs) that have been implicated in the phenotypic heterogeneity of AD pathology and pathogenesis. Understanding amyloid aggregation has been a critical limiting factor to gain understanding of AD pathogenesis, ultimately reflected in that the underlying mechanism remains elusive. We identified a fluorescent probe in the form of a turn-off photoswitchable norbornadiene derivative (NBD1) with several microenvironment-sensitive properties that make it relevant for applications within advanced fluorescence imaging, for example, multifunctional imaging. We explored the application of NBD1 for in situ delineation of structurally heterogenic Aβ plaques in transgenic AD mouse models. NBD1 plaque imaging shows characteristic broader emission bands in the periphery and more narrow emission bands in the dense cores of mature cored plaques. Further, we demonstrate in situ photoisomerization of NBD1 to quadricyclane and thermal recovery in single plaques, which is relevant for applications within both functional and super-resolution imaging. This is the first time a norbornadiene photoswitch has been used as a probe for fluorescence imaging of Aβ plaque pathology in situ and that its spectroscopic and switching properties have been studied within the specific environment of senile Aβ plaques. These findings open the way toward new applications of NBD-based photoswitchable fluorescent probes for super-resolution or dual-color imaging and multifunctional microscopy of amyloid plaque heterogeneity. This could allow to visualize Aβ plaques with resolution beyond the diffraction limit, label different plaque types, and gain insights into their physicochemical composition

Chemical traits of cerebral amyloid angiopathy in familial British-, Danish-, and non-Alzheimerʼs dementias

Familial British dementia (FBD) and familial Danish dementia (FDD) are autosomal dominant forms of dementia caused by mutations in the integral membrane protein 2B (ITM2B, also known as BRI2) gene. Secretase processing of mutant BRI2 leads to secretion and deposition of BRI2-derived amyloidogenic peptides, ABri and ADan that resemble APP/β-amyloid (Aβ) pathology, which is characteristic of Alzheimer's disease (AD). Amyloid pathology in FBD/FDD manifests itself predominantly in the microvasculature by ABri/ADan containing cerebral amyloid angiopathy (CAA). While ABri and ADan peptide sequences differ only in a few C-terminal amino acids, CAA in FDD is characterized by co-aggregation of ADan with Aβ, while in contrast no Aβ deposition is observed in FBD. The fact that FDD patients display an earlier and more severe disease onset than FBD suggests a potential role of ADan and Aβ co-aggregation that promotes a more rapid disease progression in FDD compared to FBD. It is therefore critical to delineate the chemical signatures of amyloid aggregation in these two vascular dementias. This in turn will increase the knowledge on the pathophysiology of these diseases and the pathogenic role of heterogenous amyloid peptide interactions and deposition, respectively. Herein, we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) in combination with hyperspectral, confocal microscopy based on luminescent conjugated oligothiophene probes (LCO) to delineate the structural traits and associated amyloid peptide patterns of single CAA in postmortem brain tissue of patients with FBD, FDD as well as sporadic CAA without AD (CAA+) that show pronounced CAA without parenchymal plaques. The results show that CAA in both FBD and FDD consist of N-terminally truncated- and pyroglutamate-modified amyloid peptide species (ADan and ABri), but that ADan peptides in FDD are also extensively C-terminally truncated as compared to ABri in FBD, which contributes to hydrophobicity of ADan species. Further, CAA in FDD showed co-deposition with Aβ x-42 and Aβ x-40 species. CAA+ vessels were structurally more mature than FDD/FBD CAA and contained significant amounts of pyroglutamated Aβ. When compared with FDD, Aβ in CAA+ showed more C-terminal and less N-terminally truncations. In FDD, ADan showed spatial co-localization with Aβ3pE-40 and Aβ3-40 but not with Aβx-42 species. This suggests an increased aggregation propensity of Aβ in FDD that promotes co-aggregation of both Aβ and ADan. Further, CAA maturity appears to be mainly governed by Aβ content based on the significantly higher 500/580 patterns observed in CAA+ than in FDD and FBD, respectively. Together this is the first study of its kind on comprehensive delineation of Bri2 and APP-derived amyloid peptides in single vascular plaques in both FDD/FBD and sporadic CAA that provides new insight in non-AD-related vascular amyloid pathology. (Figure presented.

Research on dynamic characteristics of three-shafts ring-plate magnet gear

Stable transmission characteristics of reduction gear play an important role in the dynamic performance and structural reliability of reduction gear. To solve the problem of mechanical gear damage of three-ring reducer and improve the working environment of the rotating bearing of the inner ring in magnetic gear with small tooth difference, due to the bearing pressure is larger, a new structure of Three-Shafts Ring-Plate Magnet Gear (TRMG) is proposed by combining the transmission mode of cycloidal permanent magnet gear and ring-plate mechanical gear. Based on its motion mechanism and dynamic model, the balance equations of force and torque of TRMG components are established, and the forces act on the input shaft and support shafts are solved by combining electromagnetic FEM and mathematical analysis. The dynamic characteristics of TRMG are optimized by changing the dynamic input mode of TRMG. Finally, the feasibility of the proposed new transmission mode is verified by multi-body dynamics analysis

Overexpression of DDX49 in prostate cancer is associated with poor prognosis

Abstract Background There is increasing evidence that DEAD-box helicases (DDX) can act either as promoters or suppressors in various cancer types. Nevertheless, the function of DDX49 in prostate cancer (PCa) is unknown. This study reveals the prognostic and predictive value of DDX49 in PCa. Methods First, we evaluated the expression of DDX49 between PCa and normal tissues based on TCGA and GEO databases. Univariate and multivariate regression analyses were conducted to reveal the risk factors for PCa recurrence. A K–M curve was employed to assess the relationship between DDX49 and recurrence-free survival. In vitro, DDX49 expression was evaluated in PCa and normal prostate cell lines. Furthermore, we constructed a shDDX49 lentivirus to knock down the expression of DDX49. Celigo® Image Cytometer and MTT assay were performed to analyse cell proliferation in PC-3 cells. Cell cycle distribution was detected with flow cytometry analysis. Apoptosis affected by the lack of DDX49 was metred with the PathScan® Stress and Apoptosis Signalling Antibody Array Kit. Results This study shows a high increase in DDX49 in PCa tissues in comparison with normal tissues and that increased DDX49 indicates a poor prognosis among PCa patients. Meanwhile, DDX49 knockdown suppressed the proliferation and migration of PC-3 cells, causing cell cycle arrest in the G1 phase. Stress and apoptosis pathway analysis revealed that the phosphorylation of HSP27, p53, and SAPK/JNK was reduced in the DDX49 knockdown group compared with the control group. Conclusions In summary, these results suggest that high expression of DDX49 predicts a poor prognosis among PCa patients. Downregulation of DDX49 can suppress cell proliferation, block the cell cycle, and facilitate cell apoptosis. Therefore, knockdown of DDX49 is a promising novel therapy for treating patients with PCa

Correlative Chemical Imaging and Spatial Chemometrics Delineate Alzheimer Plaque Heterogeneity at High Resolution

We present a novel, correlative chemical imaging strategy based on multimodal matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI), hyperspectral microscopy, and spatial chemometrics. Our workflow overcomes challenges associated with correlative MSI data acquisition and alignment by implementing 1+1-evolutionary image registration for precise geometric alignment of multimodal imaging data. This enabled multivariate statistical modeling of multimodal imaging data using a novel multiblock orthogonal component analysis approach to identify covariations of biochemical signatures between and within imaging modalities at MSI pixel resolution. We demonstrate the method’s potential through its application towards delineating chemical traits of Alzheimer’s disease (AD) pathology. Here, trimodal MALDI MSI of transgenic AD mouse brain delineates beta-amyloid (Aβ) plaque-associated co-localization of lipids and Aβ peptides. Finally, we establish an improved image fusion approach for correlative MSI and functional amyloid microscopy. This allowed high resolution prediction of correlative, multimodal MSI signatures towards distinct amyloid structures within single plaque features critically implicated in Aβ pathogenicity

Additional file 4 of Identification and validation of an E2F-related gene signature for predicting recurrence-free survival in human prostate cancer

Additional file 4: Table S4. The GSVA results of GSE116918 dataset

Additional file 2 of Identification and validation of an E2F-related gene signature for predicting recurrence-free survival in human prostate cancer

Additional file 2: Table S2. The GSVA results of TCGA-PRAD dataset

Chemical imaging of sphingolipids and phospholipids at the single amyloid-β plaque level in post-mortem human Alzheimer’s disease brain

Lipids dysregulations have been critically implicated in Alzheimer’s disease (AD) pathology. Chemical analysis of amyloid-β (Aβ) plaque pathology in transgenic AD mouse models has demonstrated alterations in the microenvironment in direct proximity to Aβ plaque pathology. In mouse studies, differences in lipid patterns linked to structural polymorphism among Aβ pathology, such as diffuse, immature, and mature fibrillary aggregate have also been reported. To date, no comprehensive analysis of neuronal lipids microenvironment changes in human AD tissue has been performed. Here, for the first time we leverage matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) though high speed and spatial resolution commercial time-of-light instrument, as well as high mass resolution in-house developed orbitrap system to characterize the lipid microenvironment in postmortem human brain tissue from AD patients carrying Presenilin 1 mutations (PSEN 1) that lead to familial forms of AD (fAD). Interrogation of the spatially resolved MSI data on a single Aβ plaque allowed us to verify nearly 40 sphingolipid and phospholipid species from diverse subclasses being enriched and depleted in relation to the Aβ deposits. This included monosialo-gangliosides (GM), ceramide monohexosides (HexCer), ceramide-1-phosphates (CerP), ceramide phosphoethanolamine conjugates (PE-Cer), sulfatides (ST), as well as phosphatidylinositols (PI), phosphatidylethanolamines (PE), and phosphatidic acid (PA) species (including Lyso-forms). Indeed, many of the sphingolipids species overlap with the species previously seen in transgenic AD mouse models. Interestingly, in comparison to the animal studies, we observed an increased localization of PE and PI species containing arachidonic acid (AA). These finding are highly relevant, demonstrating for the first time Aβ plaque pathology-related alteration in the lipid microenvironment in humans. They provide a basis for development of potential lipid biomarkers for AD characterization and insight into human-specific molecular pathway alterations

Additional file 7 of Identification and validation of an E2F-related gene signature for predicting recurrence-free survival in human prostate cancer

Additional file 7: Table S7. The results of univariate Cox regression analysis in the MSKCC cohort