Physician-reported Clinical Unmet Needs, Burden and Treatment Patterns of Paediatric Psoriasis Patients: A US and EU Real-world Evidence Study.

This study is a retrospective analysis using data collected from the Adelphi Paediatric Psoriasis Disease-Specific Programme cross-sectional survey. Despite being treated for their psoriasis, a substantial proportion of paediatric patients presented with moderate (18.3%) or severe (1.3%) disease at sampling; 42.9% and 92.0% had a body surface area (BSA) of >10%, and 38.8% and 100.0% had a Psoriasis Area Severity Index (PASI) score >10, respectively. Overall, 69.9% of patients had only ever been treated with a topical therapy for their psoriasis. For patients with moderate or severe disease at sampling, 16.3% and 14.4% were currently receiving conventional systemics or biologic therapy, respectively. There is a clinical unmet need in this paediatric population; a considerable percentage of patients still experienced moderate or severe disease and persistent psoriasis symptoms, with numerous body areas affected. A significant proportion of patients were undertreated, which may explain the high burden of disease observed.

Label-free Quantitative Proteomics of Mouse Cerebrospinal Fluid Detects ß-Site APP Cleaving Enzyme (BACE1) Protease Substrates In Vivo.

Analysis of murine cerebrospinal fluid (CSF) by quantitative mass spectrometry is challenging because of low CSF volume, low total protein concentration, and the presence of highly abundant proteins such as albumin. We demonstrate that the CSF proteome of individual mice can be analyzed in a quantitative manner to a depth of several hundred proteins in a robust and simple workflow consisting of single ultra HPLC runs on a benchtop mass spectrometer. The workflow is validated by a comparative analysis of BACE1-/- and wild-type mice using label-free quantification. The protease BACE1 cleaves the amyloid precursor protein (APP) as well as several other substrates and is a major drug target in Alzheimer's disease. We identified a total of 715 proteins with at least 2 unique peptides and quantified 522 of those proteins in CSF from BACE1-/- and wild-type mice. Several proteins, including the known BACE1 substrates APP, APLP1, CHL1 and contactin-2 showed lower abundance in the CSF of BACE1-/- mice, demonstrating that BACE1 substrate identification is possible from CSF. Additionally, ectonucleotide pyrophosphatase 5 was identified as a novel BACE1 substrate and validated in cells using immunoblots and by an in vitro BACE1 protease assay. Likewise, receptor-type tyrosine-protein phosphatase N2 and plexin domain-containing 2 were confirmed as BACE1 substrates by in vitro assays. Taken together, our study shows the deepest characterization of the mouse CSF proteome to date and the first quantitative analysis of the CSF proteome of individual mice. The BACE1 substrates identified in CSF may serve as biomarkers to monitor BACE1 activity in Alzheimer patients treated with BACE inhibitors.

Inhibition of amyloid-ß plaque formation by α-synuclein.

Amyloid-ß (Aß) plaques and α-synuclein (α-syn)-rich Lewy bodies are the major neuropathological hallmarks of Alzheimer's disease (AD) and Parkinson's disease, respectively. An overlap of pathologies is found in most individuals with dementia with Lewy bodies (DLB) and in more than 50% of AD cases. Their brains display substantial α-syn accumulation not only in Lewy bodies, but also in dystrophic neurites decorating Aß plaques. Several studies report binding and coaggregation of Aß and α-syn, yet the precise role of α-syn in amyloid plaque formation remains elusive. Here we performed intracerebral injections of α-syn-containing preparations into amyloid precursor protein (APP) transgenic mice (expressing APP695(KM670/671NL) and PSEN1(L166P) under the control of the neuron-specific Thy-1 promoter; referred to here as 'APPPS1'). Unexpectedly, α-syn failed to cross-seed Aß plaques in vivo, but rather it inhibited plaque formation in APPPS1 mice coexpressing SNCA(A30P) (referred to here as 'APPPS1 × [A30P]aSYN' double-transgenic mice). This was accompanied by increased Aß levels in cerebrospinal fluid despite unchanged overall Aß levels. Notably, the seeding activity of Aß-containing brain homogenates was considerably reduced by α-syn, and Aß deposition was suppressed in grafted tissue from [A30P]aSYN transgenic mice. Thus, we conclude that an interaction between Aß and α-syn leads to inhibition of Aß deposition and to reduced plaque formation.

Clustering of plaques contributes to plaque growth in a mouse model of Alzheimer's disease.

Amyloid-ß (Aß) plaque deposition plays a central role in the pathogenesis of Alzheimer's disease (AD). Post-mortem analysis of plaque development in mouse models of AD revealed that plaques are initially small, but then increase in size and become more numerous with age. There is evidence that plaques can grow uniformly over time; however, a complementary hypothesis of plaque development is that small plaques cluster and grow together thereby forming larger plaques. To investigate the latter hypothesis, we studied plaque formation in APPPS1 mice using in vivo two-photon microscopy and immunohistochemical analysis. We used sequential pre- and post-mortem staining techniques to label plaques at different stages of development and to detect newly emerged plaques. Post-mortem analysis revealed that a subset (22 %) of newly formed plaques appeared very close (<40 µm) to pre-existing plaques and that many close plaques (25 %) that were initially separate merged over time to form one single large plaque. Our results suggest that small plaques can cluster together, thus forming larger plaques as a complementary mechanism to simple uniform plaque growth from a single initial plaque. This study deepens our understanding of Aß deposition and demonstrates that there are multiple mechanisms at play in plaque development.