Biology subjects

Bagnoli, S.

Publications and source records attributed to Bagnoli, S..

6 recordsLinked to original sources

bioRxiv2024

Event-Related Potential Markers of Subject Cognitive Decline and Mild Cognitive Impairment during a sustained visuo-attentive task

Subjective cognitive decline (SCD), mild cognitive impairment (MCI), or severe Alzheimers disease stages are still lacking clear electrophysiological correlates. In 178 individuals (119 SCD, 40 MCI, and 19 healthy subjects (HS)), we analysed event-related potentials recorded during a sustained visual attention task, aiming to distinguish biomarkers associated with clinical conditions and task performance. We observed condition-specific anomalies in event-related potentials (ERPs) during visual encoding (P1/N1/P2) and decision-making (P300/P600/P900): SCD individuals showed attenuated dynamics compared to HS, while MCI individuals showed amplified dynamics, except for P300, which matched clinical severity. ERP features confirmed a non-monotonic trend, with MCI showing higher neural resource recruitment. Moreover, task performance correlated with condition-specific ERP gain and latencies across early and late ERP components. These findings enhanced the understanding of the neural mechanisms underlying cognitive decline in SCD and MCI and suggested potential biomarkers for early diagnosis and intervention. HighlightsO_LIIn encoding (P1/N1/P2) and decision (P600/P900) ERPs, SCD individuals showed attenuated dynamics compared to HS, while MCI individuals exhibited amplified dynamics compared to SCD. C_LIO_LIP300 dynamics matched clinical severity. C_LIO_LIMCI individuals demonstrated higher recruitment of neural resources, indicating a non-monotonic trend in ERP features between clinical conditions. C_LIO_LITask performance correlated with condition-specific gain and latencies across multiple ERP components. C_LI

neuroscience↗

bioRxiv2023

A comprehensive atlas of the aging vertebrate brain reveals signatures of progressive proteostasis dysfunction

Aging and neurodegeneration entail diverse cellular and molecular hallmarks. Here, we studied the effects of aging on the transcriptome, translatome, and multiple layers of the proteome in the brain of a short-lived killifish. We reveal that aging causes widespread reduction of proteins enriched in basic amino acids that is independent of mRNA regulation, and it is not due to impaired proteasome activity. Instead, we identify a cascade of events where aberrant translation pausing leads to reduced ribosome availability resulting in proteome remodeling independently of transcriptional regulation. Our research uncovers a vulnerable point in the aging brains biology - the biogenesis of basic DNA/RNA binding proteins. This vulnerability may represent a unifying principle that connects various aging hallmarks, encompassing genome integrity and the biosynthesis of macromolecules. One-Sentence SummaryTranslation pausing reshapes the aging brain proteome, revealing vulnerabilities in the biogenesis of nucleic-acid protein.

systems biology↗

bioRxiv2023

Proteomic analysis across patient iPSC-based models and human post-mortem hippocampal tissue reveals early cellular dysfunction, progression, and prion-like spread of Alzheimer s disease pathogenesis

The hippocampus is a primary region affected in Alzheimers disease (AD). Because AD postmortem brain tissue is not available prior to symptomatic stage, we lack understanding of early cellular pathogenic mechanisms. To address this issue, we examined the cellular origin and progression of AD pathogenesis in patient-based model systems including iPSC-derived brain cells transplanted into the mouse brain hippocampus. Notably, proteomic analysis of the graft enabled the identification of proteomic alterations in AD patient brain cells, associated with increased levels of {beta}-sheet structures and A{beta}42 peptides. Interestingly, the host cells surrounding the AD graft also presented alterations in cellular biological pathways. Furthermore, proteomic analysis across human iPSC-based models and human post-mortem hippocampal tissue projected coherent longitudinal cellular changes indicative of disease progression from early to end stage AD. Our data showcase patient-based models to study the cellular origin, progression, and prion-like spread of AD pathogenesis. Highlights- AD patient iPSC-derived brain cells survive in the hippocampus of immunodeficient mice 6 months post-transplantation. - Proteomic analysis of the grafts reveals profound alterations in cellular biological pathways in iPSC-derived hippocampal cells despite absence of senile plaques. - Proteomic alterations within transplanted AD iPSC-derived hippocampal cells are reminiscent of early/prodromal AD. - AD-grafted cells induce proteomic changes in host mouse cells.

neuroscience↗

bioRxiv2021

Aging is associated with a degeneration of noradrenergic-, but not dopaminergic-neurons, in the short-lived killifish Nothobranchius furzeri.

Parkinsons disease (PD) is characterized by phosphorylation and aggregation of the protein -Synuclein and ensuing neuronal death progressing from the noradrenergic locus coeruleus to midbrain dopaminergic neurons. In 2019, Matsui and colleagues reported in Cell Reports a spontaneous age-dependent degeneration of dopaminergic neurons and an even greater neurodegeneration of the noradrenergic neurons in the short-lived killifish Nothobranchius furzeri. Given the great possible relevance of a spontaneous model for PD, we set to confirm their results by whole-brain clarification and 3D nuclei reconstruction to quantify total cell numbers. We observed an age dependent neurodegeneration limited to the locus coeruleus and not involving the posterior tuberculum. In addition, we observed the presence of phospho-Synuclein in the soma of locus coeruleus neurons detectable already at a young age and increasing during aging. Our result demonstrates that N. furzeri models the early stages of PD, but not the degeneration of dopaminergic neurons.

neuroscience↗

bioRxiv2021

New lessons on TDP-43 from the killifish N. furzeri

Frontotemporal dementia and amyotrophic lateral sclerosis are fatal and incurable neurodegenerative diseases linked to the pathological aggregation of the TDP-43 protein. This is an essential DNA/RNA binding protein involved in transcription regulation, pre-RNA processing and RNA transport. Having suitable animal models to study the mechanisms of TDP-43 aggregation is crucial to develop treatments against disease. We have previously demonstrated that the killifish Nothobranchius furzeri offers the unique advantage as a model system that it is an organism with compressed lifespan and a conserved ageing phenotype that develops within months, making this organism the available shortest-lived vertebrate with a clear ageing phenotype. Here, we show that the two paralogs of TDP-43 from the killifish N. furzeri share high sequence homology with the human protein and recapitulate its cellular and biophysical behaviour. We prove that, during ageing, N. furzeri TDP-43 spontaneously forms insoluble intracellular TDP-43 aggregates that have amyloid characteristics and colocalize with the stress granule core protein G3BP. Our results propose this organism as a valuable model of TDP-43-related pathologies and show that even minute differences between the human and N. furzeri proteins may help to shed new light onto the role of TDP-43 in RNA recognition and granule formation.

neuroscience↗

bioRxiv2019

Reduced proteasome activity in the aging brain results in ribosome stoichiometry loss and aggregation

A progressive loss of protein homeostasis is characteristic of aging and a driver of neurodegeneration. To investigate this process quantitatively, we characterized proteome dynamics during brain aging in the short-lived vertebrate Nothobranchius furzeri combining transcriptomics and proteomics. We detected a progressive reduction in the correlation between protein and mRNA, mainly due to post-transcriptional mechanisms that account for over 40% of the age-regulated proteins. These changes cause a progressive loss of stoichiometry in several protein complexes, including ribosomes, which show impaired assembly / dis-assembly and are enriched in protein aggregates in old brains. Mechanistically, we show that reduction of proteasome activity is an early event during brain aging and is sufficient to induce proteomic signatures of aging and loss of stoichiometry in vivo. Using longitudinal transcriptomic data, we show that the magnitude of early life decline in proteasome levels is the major risk factor for mortality. Our work defines causative events in the aging process that can be targeted to prevent loss of protein homeostasis and delay the onset of age-related neurodegeneration. HighlightsO_LIProgressive loss of stoichiometry affects multiple protein complexes C_LIO_LIRibosomes aggregate in old brains C_LIO_LIPartial reduction of proteasome activity is sufficient to induce loss of stoichiometry C_LIO_LIReduced proteasome levels are a major risk factor for early death in killifish C_LI

systems biology↗