UBB+1-induced activation of autophagy reduces cytotoxicity of amyloid-β in yeast
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PROVIDER: PRJNA532446 | ENA |
REPOSITORIES: ENA
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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:UBB+1 is a mutated version of ubiquitin B peptide caused by a transcriptional frameshift due to the RNA polymerase II "slippage". The accumulation of UBB+1 has been linked to ubiquitin-proteasome system (UPS) dysfunction and neurodegeneration. Alzheimer's disease (AD) is defined as a progressive neurodegeneration and aggregation of amyloid-β peptides (Aβ) is a prominent neuropathological feature of AD. In our previous study, we found that yeast cells expressing UBB+1 at lower level display an increased resistance to cellular stresses under conditions of chronological aging. In order to examine the molecular mechanisms behind, here we performed genome-wide transcriptional analyses and molecular/cellular biology assays. We found that low UBB+1 expression activated the autophagy pathway, increased vacuolar activity, and promoted transport of autophagic marker ATG8p into vacuole. Furthermore, we introduced low UBB+1 expression to our humanized yeast AD models, that constitutively express Aβ42 and Aβ40 peptide, respectively. The co-expression of UBB+1 with Aβ42 or Aβ40 peptide led to reduced intracellular Aβ levels, ameliorated viability, and increased chronological life span. In an autophagy deficient background strain (atg1Δ), intracellular Aβ levels were not affected by UBB+1 expression. Our findings offer insights for reducing intracellular Aβ toxicity via autophagy-dependent cellular pathways under low level of UBB+1 expression.
| S-EPMC8610117 | biostudies-literature
Project description:Microglia are essential to maintain brain homeostasis, but when dysregulated, exert pathogenic functions in Alzheimer’s disease (AD). Recent evidence has implicated senescent/dystrophic microglia in the pathological process of AD. Whether microglial senescence is a cause or consequence of AD pathogenesis however is unclear. Here we report that autophagy, a lysosomal degradation pathway, restricts cellular senescence of microglia and confer neuroprotection in AD mouse model. Autophagy-deficient microglia show hallmarks of cellular senescence evidenced by reduced proliferation, increased Cdkn1a/p21Cip, dystrophy, and typical secretory phenotype. While disease-associated microglia (DAM) surrounding amyloid plaques exhibit heightened autophagy, autophagy deficient, senescent microglia (SAM) disengage from and thus fail to limit the diffusive amyloid plaques, causing enhanced tau phosphorylation and neurotoxicity in AD model. Treatment of senolytic drugs removes senescent microglia and alleviates neuropathology. Our study demonstrates a causal role of autophagy impairment in microglial senescence and neurotoxicity and suggests therapeutic potential of senolytic treatment for AD.
2023-04-24 | GSE192964 | GEO
Project description:Potassium starvation induces autophagy in yeast
| PRJNA637607 | ENA
Project description:Deposition of amyloid beta (Aβ) and hyperphosphorylated tau along with glial cell-mediated neuroinflammation are prominent pathogenic hallmarks of Alzheimer’s disease (AD). In recent years, impairment of autophagy has been found to be another important feature contributing to AD progression. Therefore, the potential of the autophagy activator spermidine, a small body-endogenous polyamine often used as dietary supplement, was assessed on Aβ pathology and glial cell-mediated neuroinflammation. Oral treatment of the amyloid prone AD-like APPPS1 mice with spermidine reduced neurotoxic soluble Aβ and decreased AD-associated neuroinflammation during disease progression. Mechanistically, single nuclei sequencing revealed AD-associated microglia to be the main target of spermidine. This microglia population was characterized by increased AXL levels and expression of genes implicated in cell migration and phagocytosis. Our data highlight that the autophagy activator spermidine holds the potential to enhance Aβ degradation and to counteract glia-mediated neuroinflammation in AD pathology.
2022-07-04 | GSE206202 | GEO
Project description:Metabolic profiling in wild type and autophagy-deficient human embryonic stem cell (hESC)-derived neurons after 3 weeks of neuronal differentiation.
Autophagy is a homeostatic process critical for cellular survival, and its malfunction is implicated in myriad human diseases including neurodegeneration. Loss of autophagy contributes to cytotoxicity and tissue degeneration, but the mechanistic understanding of this phenomenon remains elusive. Here we have generated autophagy-deficient human embryonic stem cells (hESCs), from which we have established human neuronal platform to investigate how loss of autophagy affects neuronal survival. ATG5 deficient neurons exhibit basal cytotoxicity accompanied by metabolic defects. Depletion of nicotinamide adenine dinucleotide (NAD) due to hyperactivation of NAD-consuming enzymes is found to trigger cell death via mitochondrial depolarisation in ATG5 deficient neurons. Boosting intracellular NAD levels improve cell viability by restoring mitochondrial bioenergetics and proteostasis in ATG5 deficient neurons. Our findings elucidate a mechanistic link between autophagy deficiency and neuronal cell death that can be targeted for therapeutic interventions in neurodegenerative and lysosomal storage diseases associated with autophagic defect.
2023-03-10 | MSV000091468 | MassIVE
Project description:Complement inhibitor C4b-binding protein (C4BP) is synthesized in liver and pancreas and composed of 7 identical alpha chains and one unique beta chain. We showed previously that C4BP binds islet amyloid polypeptide (IAPP) and affects fibril formation in vitro. Now we found that polymeric C4BP inhibited lysis of human erythrocytes incubated with monomeric IAPP while no erythrocyte lysis was observed after incubation with preformed IAPP fibrils. In contrast, monomeric alpha chain of C4BP had significantly reduced activity. Further, addition of monomeric IAPP to a rat insulinoma cell line (INS-1) resulted in decreased cell viability, which was restored in the presence of physiological concentrations of C4BP. Accordingly, addition of C4BP rescued the ability of INS-1 cells and isolated rat islets to respond to glucose stimulation with insulin secretion, which was impaired in the presence of IAPP alone. C4BP was internalized together with IAPP into INS-1 cells and therefore we aimed to study its effect on gene expression. Pathway analyses of mRNA expression microarray data indicated that cells exposed to C4BP and IAPP in comparison to IAPP alone increased expression of genes involved in cholesterol synthesis. Depletion of cholesterol through methyl-β-cyclodextrin or cholesterol oxidase abolished the protective effect of C4BP on IAPP cytotoxicity of INS-1 cells. Also, inhibition of phosphoinositide 3-kinase but not NF-κB had a similar effect. Taken together, one of the mechanisms by which C4BP protects beta-cells from IAPP cytotoxicity is by enhancing cholesterol synthesis. The INS-1 cells were grown as 5 separate clones for 10 passages before plating in a 12-well plate (Nunc) at 100.000 cells per well and grown in complete RPMI 1640 medium to 70% confluency for approximately 48 h. The cells were then challenged by adding 77 μM monomeric IAPP alone or together with C4BP (0.6 μM). DMSO (1%) used as solvent for IAPP as well as C4BP (0.6 μM) alone were used as controls. RNA was extracted after 10h incubation and analysis carried out using Rat Gene 2.0 array chip (Affymetrix).
2016-08-25 | E-GEOD-79224 | biostudies-arrayexpress
Project description:Metabolic profiling in wild type and autophagy-deficient human embryonic stem cell (hESC)-derived neurons after 3 weeks of neuronal differentiation.
Autophagy is a homeostatic process critical for cellular survival, and its malfunction is implicated in myriad human diseases including neurodegeneration. Loss of autophagy contributes to cytotoxicity and tissue degeneration, but the mechanistic understanding of this phenomenon remains elusive. Here we have generated autophagy-deficient human embryonic stem cells (hESCs), from which we have established human neuronal platform to investigate how loss of autophagy affects neuronal survival. ATG5 deficient neurons exhibit basal cytotoxicity accompanied by metabolic defects. Depletion of nicotinamide adenine dinucleotide (NAD) due to hyperactivation of NAD-consuming enzymes is found to trigger cell death via mitochondrial depolarisation in ATG5 deficient neurons. Boosting intracellular NAD levels improve cell viability by restoring mitochondrial bioenergetics and proteostasis in ATG5 deficient neurons. Our findings elucidate a mechanistic link between autophagy deficiency and neuronal cell death that can be targeted for therapeutic interventions in neurodegenerative and lysosomal storage diseases associated with autophagic defect.
2023-03-10 | MSV000091468 | GNPS
Project description:Alzheimer’s disease (AD) is the most common form of neurodegenerations, with oligomerization and aggregation of amyloid-β peptides (Aβ) being one of its histopathological hallmarks. Recently, graphene oxide (GO) nanoflakes have attracted significant attention in biomedical fields by suppression of protein aggregation in vitro. However, the impact of GO on aggregated proteins in vivo is poorly understood. In earlier work, we developed a humanized AD model in yeast Saccharomyces cerevisiae by constitutively expressing Aβ42 peptides to mimic the chronic cytotoxicity during AD progression. Here we apply this in vivo model system to investigate the impact of GO on Aβ42 aggregates and cytotoxicity.
2023-09-28 | PXD029382 | Pride
Project description:Synthesis and degradation of cellular constituents must be balanced to maintain cellular homeostasis, especially during adaptation to environmental stress. The role of autophagy in the degradation of proteins and organelles is well-characterized. However, autophagy-mediated RNA degradation in response to stress and the potential preference of specific RNAs to undergo autophagy-mediated degradation have not been examined. In this study, we demonstrate selective mRNA degradation by rapamycin-induced autophagy in yeast. Profiling of mRNAs from the vacuole reveals that subsets of mRNAs, such as those encoding amino acid biosynthesis and ribosomal proteins, are preferentially delivered to the vacuole by autophagy for degradation. We also reveal that autophagy-mediated mRNA degradation is tightly coupled with translation by ribosomes. Genome-wide ribosome profiling suggested a high correspondence between ribosome association and targeting to the vacuole. We propose that autophagy-mediated mRNA degradation is a unique and previously-unappreciated function of autophagy that affords post-transcriptional gene regulation.
2021-03-08 | GSE149016 | GEO