CD5L promotes phagocytic removal of Amyloid β oligomers and improves cognitive function in a mouse model of Alzheimer's disease
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE324992 | GEO | 2026/04/20
REPOSITORIES: GEO
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Project description:Alzheimer's disease (AD), a neurodegenerative disorder, is the leading cause of dementia. Amyloid-beta (Aβ) and tau are major contributors to AD onset and progression. Here, we investigate the therapeutic potential of CD5L, a macrophage-specific secretory protein, in reducing Aβ accumulation and improving AD pathology. CD5L directly binds to Aβ, particularly the neurotoxic Aβ42, and blocks their aggregation. Moreover, CD5L enhances microglial phagocytosis against several forms of Aβ40 and Aβ42. In 5xFAD mice, a well-established AD murine model, forced expression of CD5L reduced Aβ plaque size and number. RNA sequencing revealed that CD5L promotes phagocytic activity in microglia within the 5xFAD mouse brain. Furthermore, adeno-associated virus (AAV)-mediated delivery of CD5L improved cognitive function, as demonstrated by enhanced performance in the T-maze test. These findings highlight the role of CD5L in inhibiting Aβ aggregation and facilitating Aβ clearance via enhanced phagocytosis, offering a promising therapeutic strategy for AD.
2026-04-20 | GSE325126 | GEO
Project description:A defining hallmark of Alzheimer's disease (AD) is the synaptic aggregation of the amyloid beta (Aβ) peptide. In vivo, Aβ production results in a diverse mixture of variants, of which Aβ40, Aβ42, and Aβ43 are profusely present in the AD brain, and their relative abundance is recognised to play a role in disease onset and progression. Nonetheless, the occurrence of Aβ40, Aβ42, and Aβ43 hetero-oligomerisation and the subsequent effects on Aβ aggregation remain elusive and were investigated here. Using thioflavin-T (ThT) monitored aggregation assays and native mass spectrometry coupled to ion mobility analysis (IM-MS), we first show that all Aβ peptides are aggregation-competent and self-assemble into homo-oligomers with distinct conformational populations, which are more pronounced between Aβ40 than the longer variants. ThT assays were then conducted on binary mixtures of Aβ variants, revealing that Aβ42 and Aβ43 aggregate independently from Aβ40, but significantly speed-up Aβ40 fibrillation. Aβ42 and Aβ43 were observed to aggregate concurrently and mutually accelerate fibril formation, which likely involves hetero-oligomerisation. Accordingly, native MS analysis revealed pairwise oligomerisation between all variants, with the formation of heterodimers and heterotrimers. Interestingly, IM-MS indicates that hetero-oligomers containing longer Aβ variants are enriched in conformers with lower collision-cross sections when compared to their homo-oligomer counterparts. This suggests that Aβ42 and Aβ43 are capable of remodelling oligomer structure towards a higher compaction level. Altogether, our findings provide a mechanistic description for the hetero-oligomerisation of Aβ variants implicated in AD, contributing to rationalising their in vivo proteotoxic interplay.
2025-01-31 | PXD057653 | Pride
Project description:Proteins associated with amyloid-β (Aβ) pathology are critical biomarkers and potential therapeutic targets for Alzheimer’s disease (AD). Previous studies analyzing Aβ plaque composition relied on micro-dissected plaques from tissue samples. Here, we aimed to study the proteome associated with Aβ40- and Aβ42-plaques to identify protein constituents of Aβ plaques—actual Aβ40- and Aβ42-fibril interactors—, which might drive Aβ plaque development. Biotinylated-Aβ40, or -Aβ42, were incubated to form fibrils, with scrambled peptides used as control, and subjected to pull-down assays using protein extracts from AD and control prefrontal cortex tissues. Aβ-interacting proteins were identified by proteomics. Their dysregulation was assessed in AD tissue samples and a cellular AD model by WB, immunocytochemistry, in silico, and immunohistochemistry. We identified 185 and 874 proteins associated with Aβ40- and Aβ42-fibrils, respectively, with 78 in common. Sixteen were validated as interactors by WB and ex vivo as components of Aβ plaques by IF, displaying altered expression in AD and supporting a functional role for PRKCG in amyloidogenesis, as its modulation alters Aβ fibril formation. This study expands the Aβ plaque-associated proteome characterization, identifies novel fibril interactors, and highlight potential therapeutic targets, as the modulation of PRKCG prevent or reduce Aβ plaque formation in AD.
2026-01-24 | PXD061100 | Pride
Project description:Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. Oligomers of Amyloid-β peptides (Aβ) are thought to play a pivotal role in AD pathogenesis, yet the mechanisms involved remain unclear. Two major isoforms of Aβ associated with AD are Aβ40 and Aβ42, the latter being more prone to form oligomers and toxic. Humanized yeast models are currently applied to unravel the cellular mechanisms behind Aβ toxicity. Here, we took a systems biology approach to study two yeast AD models which expressed either Aβ40 or Aβ42 in bioreactor cultures. Strict control of oxygen availability and culture pH, strongly affected the chronological lifespan and reduced confounding effects of variations during cell growth. Reduced growth rates and biomass yields were observed upon expression of Aβ42, indicating a redirection of energy from growth to maintenance. Quantitative physiology analyses furthermore revealed reduced mitochondrial functionality and ATP generation in Aβ42 expressing cells, which matched with observed aberrant fragmented mitochondrial structures. Genome-wide expression levels analysis showed that Aβ42 expression triggers strong ER stress and unfolded protein responses (UPR). Expression of Aβ40 induced only mild ER stress, leading to activation of UPR target genes that cope with misfolded proteins, which resulted in hardly affected physiology. The combination of well-controlled cultures and AD yeast models strengthen our understanding of how cells translate different levels of Aβ toxicity signals into particular cell fate programs, and further enhance their role as a discovery platform to identify potential therapies.
2017-08-31 | GSE94793 | GEO
Project description:Despite the importance of Aβ aggregation in Alzheimer’s disease etiology, our understanding of the sequence determinants of aggregation is sparse and largely derived from in vitro studies. For example, in vitro proline and alanine scanning mutagenesis of Aβ40 proposed core regions important for aggregation. However, we lack even this limited mutagenesis data for the more disease-relevant Aβ42. Thus, to better understand the molecular determinants of Aβ42 aggregation in a cell-based system, we combined a yeast DHFR aggregation assay with deep mutational scanning. We measured the effect of 791 of the 798 possible single amino acid substitutions on the aggregation propensity of Aβ42. We found that ~75% of substitutions, largely to hydrophobic residues, maintained or increased aggregation. We identified 11 positions at which substitutions, particularly to hydrophilic and charged amino acids, disrupted Aβ aggregation. These critical positions were similar but not identical to critical positions identified in previous Aβ mutagenesis studies. Finally, we analyzed our large-scale mutagenesis data in the context of different Aβ aggregate structural models, finding that the mutagenesis data agreed best with models derived from fibrils seeded using brain-derived Aβ aggregates.
2019-10-21 | GSE139122 | GEO
Project description:The gut microbiota and innate immune system play critical roles in Alzheimer’s disease (AD). Bacteroides is elevated in AD patients and correlates with cerebrospinal fluid levels of Aβ and tau. We found that increased amyloid-β (Aβ) plaques in Bacteroides fragilis treated APP/PS1-21 mice were associated with altered cortical expression Aβ processing genes. B. fragilis suppressed peripheral CD4+ T cell production of GM-CSF and IL-4 and transcriptional changes in microglia related to GM-CSF and IL-4 signaling, phagocytosis, and protein degradation. Furthermore, B. fragilis impaired the microglial uptake of intracranially injected Aβ42, whereas Erysipelotrichaceae strains increased uptake. Depleting murine Bacteroidetes with metronidazole decreased amyloid load in aged 5xFAD mice, increased CD4+ T cell GM-CSF production, and activated microglial pathways related to cytokine signaling, phagocytosis and lysosomal degradation. These data suggest that the gut microbiome may contribute to AD pathogenesis by suppressing peripheral cytokines and microglia phagocytic function, leading to impaired immune-mediated Aβ clearance.
2024-10-12 | GSE215439 | GEO
Project description:The gut microbiota and innate immune system play critical roles in Alzheimer’s disease (AD). Bacteroides is elevated in AD patients and correlates with cerebrospinal fluid levels of Aβ and tau. We found that increased amyloid-β (Aβ) plaques in Bacteroides fragilis treated APP/PS1-21 mice were associated with altered cortical expression Aβ processing genes. B. fragilis suppressed peripheral CD4+ T cell production of GM-CSF and IL-4 and transcriptional changes in microglia related to GM-CSF and IL-4 signaling, phagocytosis, and protein degradation. Furthermore, B. fragilis impaired the microglial uptake of intracranially injected Aβ42, whereas Erysipelotrichaceae strains increased uptake. Depleting murine Bacteroidetes with metronidazole decreased amyloid load in aged 5xFAD mice, increased CD4+ T cell GM-CSF production, and activated microglial pathways related to cytokine signaling, phagocytosis and lysosomal degradation. These data suggest that the gut microbiome may contribute to AD pathogenesis by suppressing peripheral cytokines and microglia phagocytic function, leading to impaired immune-mediated Aβ clearance.
2024-10-12 | GSE215438 | GEO
Project description:UBB+1 is a mutated version of ubiquitin B caused by a transcriptional frameshift. The accumulation of UBB+1, has been linked to ubiquitin-proteasome system (UPS) dysfunction and neurodegeneration. Alzheimer’s disease (AD) is the most common form of neurodegeneration and accumulation of amyloid β (Aβ) in the brain is a prominent neuropathological feature of AD. In our previous study, we found that low expression of UBB+1 could protect cells against several stresses during chronological aging. Here, we applied the genome-wide expression analyses and found that low UBB+1 expression activated the autophagy pathway. Low UBB+1 expression was shown to upregulate vacuolar activity and promote transport of the ATG8p (autophagic marker) to the vacuole. To further study the effects, we expressed low level of UBB+1 in our humanized yeast Aβ models with the expression of either Aβ42 or Aβ40. Interestingly, the co-expression of UBB+1 with Aβ42 or Aβ40 showed a reduction of intracellular Aβ levels and increased chronological life span. In the autophagy deficient mutant background (atg1∆), the intracellular Aβ levels were not affected by UBB+1 expression. Our findings suggest a mechanism of UBB+1 action in reducing intracellular levels of Aβ.
2021-03-12 | GSE129688 | GEO
Project description:In order to identify endogenous factors that modulate Aβ production, we performed a transcriptome analysis on neuronal cells derived from human induced pluripotent stem cells (hiPS) because these cells changed the Aβ production during neuronal differentiation. When the expression of APP and the ratio Aβ42/40 of the secreted proteins were measured at days 38, 45, and 52 during differentiation, both APP expression and the secretion of Aβ40 and Aβ42 at days 45 and 52 were significantly increased compared to those at day 38. Furthermore, the ratio of Aβ42/40 was dramatically reduced at days 45 and 52 compared to that at day 38. We hypothesized that transcriptional changes during the differentiation into neuronal cells may affect APP production and/or processing. To test this hypothesis, we performed microarray analyses using three independent neuronal cell cultures that were differentiated from each of three hiPS cells, namely 201B7, 253G4, and AD4F-1 (nine cell lines in total). Total RNA was prepared at three differentiation time points (days 38, 45, and 52) and subjected to an Affymetrix Gene Chip Human Exon 1.0 ST array. Compare between samples from 38-day cultures and samples from 45- and 52-day cultures.
2020-01-24 | E-MTAB-7852 | biostudies-arrayexpress
Project description:Gamma oscillations (20-50Hz) are a common local field potential signature in many brain regions that are generated by a resonant circuit between fast-spiking parvalbumin (PV)-positive interneurons and pyramidal cells. Changes in the magnitude and frequency of gamma have been observed in several neuropsychiatric disorders. However, it is unclear how disruptions in gamma oscillations affect cellular pathologies seen in these disorders. Here, we investigate this using the 5XFAD mouse model of Alzheimer’s disease (AD) and find reduced power and magnitude of behaviorally driven gamma oscillatory activity — even before the onset of plaque formation or measurable cognitive decline. Because of the early onset, we aimed to determine if exogenous manipulations of gamma could influence the progression of disease pathology. We find that driving PV-positive neurons at gamma frequency (40Hz) using channelrhodopsin-2 reduced total levels of amyloid-β (Aβ) 40 and 42 isoforms in the hippocampus of 5XFAD mouse. Driving PV-positive neurons at other frequencies, or driving excitatory neurons, did not reduce Aβ levels. Furthermore, driving PV-positive neurons reduced enlarged endosomes in hippocampal neurons and cleavage intermediates of APP in 5XFAD mouse. Gene expression profiling revealed a neuroprotective response with morphological transformation of microglia and markedly increased phagocytosis of Aβ by microglia. Inspired by these observations, we designed a non-invasive light-flickering paradigm that drives 40Hz gamma activity in mouse visual cortex. The light-flickering paradigm profoundly reduced Aβ40 and Aβ42 levels in the visual cortex of pre-symptomatic mice and greatly mitigated plaque load in the visual cortex of aged, symptomatic mice. This reduction was completely blocked by a GABA-A antagonist, providing further support for an essential role of GABAergic signaling in mediating neuroprotective gamma activity. Overall, our findings uncover a dramatic and previously unappreciated function of the brain’s endogenous gamma rhythms in reducing the production and increasing the clearance of Aβ peptides, whose accumulation is believed to drive the pathogenesis of AD.
2016-12-07 | GSE77471 | GEO