Domain-Independent Inhibition of CBP/p300 Attenuates α-Synuclein Aggregation.
Ontology highlight
ABSTRACT:
SUBMITTER: Hlushchuk I
PROVIDER: S-EPMC8291498 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:RationaleSynucleinopathies, including Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), share a distinct pathological feature, that is, a widespread accumulation of α-synuclein (α-syn) in the brain. There is a significant clinical unmet need for disease-modifying treatments for synucleinopathies. Recently, a seaweed-derived mixture of oligosaccharides sodium oligomannate, GV-971, was approved for Phase 2 clinical trials for PD. This study aimed to further evaluate the therapeutic effects of GV-971 on synucleinopathies using cellular and animal models and explore its associated molecular mechanisms.Methodsα-Syn aggregation was assessed, in vitro and ex vivo, by ThT assay. A dopaminergic neuron cell line, Prnp-SNCAA53T mice, and brain slices from PD and DLB patients were used to determine the efficacy of GV-971 in ameliorating α-syn pathology. Measurements of motor functions, including pole, cylinder, and rotarod tests, were conducted on Prnp-SNCAA53T mice 4 weeks after intragastric administration of GV-971 (200 mg day-1 kg-1 ).ResultsGV-971 effectively prevented α-syn aggregation and even disassembled pre-aggregated α-syn fibrils, in vitro and ex vivo. In addition, GV-971 was able to rescue α-syn-induced neuronal damage and reduced release of extracellular vesicles (EVs), likely via modulating Alix expression. In the Prnp-SNCAA53T mouse model, when treated at the age of 5 months, GV-971 significantly decreased α-syn deposition in the cortex, midbrain, and cerebellum regions, along with ameliorating the motor dysfunctions.ConclusionsOur results indicate that GV-971, when administered at a relatively early stage of the disease process, significantly reduced α-syn accumulation and aggregation in Prnp-SNCAA53T mice. Furthermore, GV-971 corrected α-syn-induced inhibition of EVs release in neurons, contributing to neuronal protection. Future studies are needed to further assess GV-971 as a promising disease-modifying therapy for PD and other synucleinopathies.
| S-EPMC10848097 | biostudies-literature
Project description:α-Synuclein (aSyn) aggregation is an attractive target for therapeutic development for a range of neurodegenerative conditions, collectively termed synucleinopathies. Here, we probe the mechanism of action of a peptide 4554W, (KDGIVNGVKA), previously identified through intracellular library screening, to prevent aSyn aggregation and associated toxicity. We utilize NMR to probe association and identify that 4554W associates with a "partially aggregated" form of aSyn, with enhanced association occurring over time. We also report the ability of 4554W to undergo modification through deamidation of the central asparagine residue, occurring on the same timescale as aSyn aggregation in vitro, with peptide modification enhancing its association with aSyn. Additionally, we report that 4554W can act to reduce fibril formation of five Parkinson's disease associated aSyn mutants. Inhibitory peptide binding to partially aggregated forms of aSyn, as identified here, is particularly attractive from a therapeutic perspective, as it would eliminate the need to administer the therapy at pre-aggregation stages, which are difficult to diagnose. Taken together the data suggest that 4554W could be a suitable candidate for future therapeutic development against wild-type, and most mutant aSyn aggregation.
| S-EPMC7594713 | biostudies-literature
Project description:p300 and CBP participate as transcriptional coregulators in the execution of a wide spectrum of cellular gene expression programs controlling cell differentiation, growth and homeostasis. Both proteins act together with sequence-specific transcription factors to modify chromatin structure of target genes via their intrinsic acetyltransferase activity directed towards core histones and some transcription factors. So far, p300-related proteins have been described in animals ranging from Drosophila and Caenorhabditis elegans to humans. In this report, we describe p300/CBP-like polypeptides in the plant Arabidopsis thaliana. Interestingly, homology between animal and plant p300/CBP is largely restricted to a C-terminal segment, about 600 amino acids in length, which encompasses acetyltransferase and E1A-binding domains. We have examined whether this conservation in sequence is paralleled by a conservation in function. The same amino acid residues critical for acetyltransferase activity in human p300 are also critical for the function of one of the plant orthologs. Remarkably, plant proteins bind to the adenovirus E1A protein in a manner recapitulating the binding specificity of mammalian p300/CBP. The striking conservation of an extended segment of p300/CBP suggests that it may constitute a functional entity fulfilling functions that may be essential for all metazoan organisms.
| S-EPMC30400 | biostudies-literature
Project description:p300/CBP-associated factor (PCAF), a histone acetyltransferase, is involved in many cellular processes such as differentiation, proliferation, apoptosis, and reaction to cell damage by modulating the activities of several genes and proteins through the acetylation of either the histones or transcription factors. Here, we examined a pathogenic role of PCAF and its potential as a novel therapeutic target in the progression of renal tubulointerstitial fibrosis induced by non-diabetic unilateral ureteral obstruction (UUO) in male C57BL/6 mice. Administration of garcinol, a PCAF inhibitor, reversed a UUO-induced increase in the renal expression of total PCAF and histone 3 lysine 9 acetylation and reduced positive areas of trichrome and α-smooth muscle actin and collagen content. Treatment with garcinol also decreased mRNA levels of transforming growth factor-β, matrix metalloproteinase (MMP)-2, MMP-9, and fibronectin. Furthermore, garcinol suppressed nuclear factor-κB (NF-κB) and pro-inflammatory cytokines such as tumor necrosis factor-α and IL-6, whereas it preserved the nuclear expression of nuclear factor erythroid-derived 2-like factor 2 (Nrf2) and levels of Nrf2-dependent antioxidants including heme oxygense-1, catalase, superoxide dismutase 1, and NAD(P)H:quinone oxidoreductase 1. These results suggest that the inhibition of inordinately enhanced PCAF could mitigate renal fibrosis by redressing aberrant balance between inflammatory signaling and antioxidant response through the modulation of NF-κB and Nrf2.
| S-EPMC6479343 | biostudies-literature
Project description:The GACKIX activator binding domain has been a compelling target for small-molecule probe discovery because of the central role of activator-GACKIX complexes in diseases ranging from leukemia to memory disorders. Additionally, GACKIX is an ideal model to dissect the context-dependent function of activator-coactivator complexes. However, the dynamic and transient protein-protein interactions (PPIs) formed by GACKIX are difficult targets for small molecules. An additional complication is that activator-binding motifs, such as GACKIX, are found in multiple coactivators, making specificity difficult to attain. In this study, we demonstrate that the strategy of tethering can be used to rapidly discover highly specific covalent modulators of the dynamic PPIs between activators and coactivators. These serve as both ortho- and allosteric modulators, enabling the tunable assembly or disassembly of the activator-coactivator complexes formed between the KIX domain and its cognate activator binding partners MLL and CREB. The molecules maintain their function and selectivity, even in human cell lysates and in bacterial cells, and thus, will ultimately be highly useful probes for cellular studies.
| S-EPMC10900128 | biostudies-literature
Project description:Several genetic and environmental risk factors for Parkinson’s disease have been identified that converge on mitochondria as central elements in the disease process. However, the mechanisms by which mitochondrial dysfunction contributes to neurodegeneration remain incompletely understood. Non-bioenergetic pathways of the mitochondria are increasingly appreciated, but confounding bioenergetic defects are a major barrier to experimental validation. Here, we describe a novel bioenergetics-independent mechanism by which mild mitochondrial protein import stress augments neurodegeneration. We induced this mitochondrial protein import stress in an established mouse model of Parkinson’s disease expressing the A53T mutated form of human alpha-synuclein (SNCA). Mice with import stress in addition to the A53T mutation demonstrated increased size of SNCA aggregates, co-aggregation of mitochondrial preproteins with SNCA protein, worsened neurodegeneration and changes in gene expression, as determined by whole-transcriptome RNA-sequencing analysis of the forebrain (striatum), cerebellum, spinal cord, as well as heart and skeletal muscle.
2023-10-08 | GSE236975 | GEO
Project description:Lysine acetylation is becoming increasingly recognized as a general biological principle in cellular homeostasis, and is subject to abnormal control in different human pathologies. Here, we describe a global effect on amyloid-like protein aggregation in human cells that results from aberrant lysine acetylation. Bromodomain reader proteins are involved in the aggregation process and, using chemical biology and gene silencing, we establish that p300/CBP bromodomains are necessary for aggregation to occur. Moreover, protein aggregation disturbs proteostasis by impairing the ubiquitin proteasome system (UPS) and protein translation, resulting in decreased cell viability. p300/CBP bromodomain inhibitors impede aggregation, which coincides with enhanced UPS function and increased cell viability. Aggregation of a pathologically relevant form of huntingtin protein is similarly affected by p300/CBP inhibition. Our results have implications for understanding the molecular basis of protein aggregation, and highlight the possibility of treating amyloid-like pathologies and related protein folding diseases with bromodomain inhibitor-based strategies.
| S-EPMC5266481 | biostudies-literature
Project description:The pathological accumulation of α-Synuclein (α-Syn) is the hallmark of neurodegenerative α-synucleinopathies, including Parkinsons's disease (PD). In contrast to the mostly non-phosphorylated soluble α-Syn, aggregated α-Syn is usually phosphorylated at serine 129 (S129). Therefore, S129-phosphorylation is suspected to interfere with α-Syn aggregation. Among other kinases, protein kinase CK1 (CK1) is known to phosphorylate α-Syn at S129. We overexpressed CK1 binding protein (CK1BP) to inhibit CK1 kinase activity. Using Bimolecular Fluorescence Complementation (BiFC) in combination with biochemical methods, we monitored the S129 phosphorylation and oligomerization of α-Syn in HEK293T cells. We found that CK1BP reduced the overall protein levels of α-Syn. Moreover, CK1BP concomitantly reduced S129 phosphorylation, oligomerization and the amount of insoluble α-Syn. Analyzing different α-Syn variants including S129 mutations, we show that the effects of CK1BP on α-Syn accumulation were independent of S129 phosphorylation. Further analysis of an aggregating polyglutamine (polyQ) protein confirmed a phosphorylation-independent decrease in aggregation. Our results imply that the inhibition of CK1 activity by CK1BP might exert beneficial effects on NDDs in general. Accordingly, CK1BP represents a promising target for the rational design of therapeutic approaches to cease or at least delay the progression of α-synucleinopathies.
| S-EPMC8616157 | biostudies-literature
Project description:Parkinson's disease (PD) is linked to the aberrant self-assembly of the amyloid protein, α-synuclein (αS), where αS monomers aggregate to form oligomers and fibrils. Out of the three conformers, αS oligomers are the major toxic agents in PD, while αS fibrils may work as a reservoir for toxic oligomeric conformers. Thus, compounds that inhibit aggregation of αS monomers and disaggregate αS oligomers and fibrils may serve as therapeutic agents against PD. In this regard, resveratrol and its synthetic derivatives (e.g., AM17, which contains a copper ion-selective ionophoric motif) have previously been examined for their inhibitory effects on aggregation of amyloid proteins, such as the β-amyloid peptide implicated in Alzheimer's disease. In the current study, we employed an array of experimental tools, such as Thioflavin T fluorescence, transmission electron microscopy, immuno-dot blot assays, SDS- and native-PAGE, and circular dichroism, to determine the impact of AM17 and resveratrol on αS aggregation. To the best of our knowledge, we show for the first time that AM17 not only inhibits aggregation of αS monomers but also disaggregates αS oligomers and fibrils, independent of the copper ions. Similar αS aggregation inhibitory effects were observed with resveratrol only in the presence of the copper ion. The present study supports the high promise of applicability of AM17 as an effective amyloid aggregation inhibitor for various conformers and protein sequences.
| S-EPMC8431946 | biostudies-literature
Project description:Using NMR spectroscopy, we identified and characterized a previously unrecognized structured domain near the N-terminus (residues 35-121) of the ETS family transcription factor GABP alpha. The monomeric domain folds as a five-stranded beta-sheet crossed by a distorted helix. Although globally resembling ubiquitin, the GABP alpha fragment differs in its secondary structure topology and thus appears to represent a new protein fold that we term the OST (On-SighT) domain. The surface of the GABP alpha OST domain contains two predominant clusters of negatively-charged residues suggestive of electrostatically driven interactions with positively-charged partner proteins. Following a best-candidate approach to identify such a partner, we demonstrated through NMR-monitored titrations and glutathione S-transferase pulldown assays that the OST domain binds to the CH1 and CH3 domains of the co-activator histone acetyltransferase CBP/p300. This provides a direct structural link between GABP and a central component of the transcriptional machinery.
| S-EPMC2486348 | biostudies-literature