Distinct sub-cellular autophagy impairments occur independently of protein aggregation in aged induced neurons from patients with Huntington’s disease
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PROVIDER: PRJNA703003 | ENA |
REPOSITORIES: ENA
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Project description:Huntington’s disease (HD) is an inherited neurodegenerative disorder caused by CAG expansions in the huntingtin (HTT) gene. Modelling HD in the lab has proven challenging as rodent models poorly reproduce the disease process and cellular models fail to include age-dependent processes crucial to the disease. Here we generated induced neurons (iNs) that retained age-dependent epigenetic characteristics of the donors through direct reprogramming of skin fibroblasts. HD-iNs displayed a transcriptionally regulated, distinct neurite specific alteration in autophagy, characterized by reduced transport of late autophagic structures and subsequent cargo degradation. In addition, HD-iNs displayed shorter, smaller and fewer neurites. CRISPRi-mediated silencing of both HTT alleles did not rescue the morphology nor the autophagic defect in HD-iNs. Strikingly, it resulted in additional autophagy alterations when done using ctrl-iNs, highlighting the importance of wt HTT in neuronal autophagy. In summary, our results have identified a distinct subcellular autophagy impairment in aged patient derived HD-neurons. In addition, we have shown a role for normal wt HTT in autophagy. Together this work provides a new rational for future development of autophagy activation therapies while also highlighting problems that may arise using non allele specific HTT silencing approaches, some of which are now in clinical trials.
2022-02-01 | GSE167104 | GEO
Project description:Huntington’s disease (HD) is an inherited neurodegenerative disorder that is caused by CAG expansions in the huntingtin (HTT) gene. Modelling HD in the lab has proven challenging as rodent models poorly reproduce the disease process and cellular models fail to include age-dependent processes crucial to the expression of the disease clinically. Here we generated induced neurons (iNs) through direct reprogramming of skin fibroblasts from HD-patients. This resulted in the generation of patient-derived HD neurons that retained age-dependent epigentic characteristics of the donors. Using these cells, we then undertook a proteomic analysis and demonstrated there was an alteration in the CAMKK-AMPK pathway and autophagy in these HD-iNs, compared to healthy control iN cells. In line with this, HD-iNs displayed a distinct subcellular alteration in autophagy, specifically in the neurites, characterized by a reduction in the transport of late autophagic structures between neurites and the soma and subsequent cargo degradation. In addition to which the HD-iNs displayed shorter, smaller and fewer neurites. CRISPRi-mediated silencing of HTT (both wt and mutant) did not rescue the morphology nor could this rescue the autophagic defect in HD-iNs and indeed resulted in additional autophagy alterations when done using ctrl-iNs, highlighting the importance of wild type HTT in neuronal autophagy. In summary, our results have identified a distinct subcellular autophagy impairment in aged patient derived HD-neurons. In addition, we have shown a role for normal wt Htt in autophagy. Together this work provides a new rational for future development of autophagy activation therapies while also highlighting problems that may arise using non allele specific htt silencing approaches, some of which are now in clinical trials.
2022-10-14 | PXD024286 | Pride
Project description:Distinct sub-cellular autophagy impairments independent of protein aggregation in induced neurons from patients with Huntington disease
| PRJNA758255 | ENA
Project description:Huntington’s disease is a fatal autosomal dominant neurodegenerative disorder, characterized by neuronal cell loss, primarily in the striatum, cortex, and hippocampus, causing motor, cognitive, and psychiatric impairments. Unfortunately, no treatments are yet available to modify the progression of the disease. Recent evidence from Huntington’s disease mouse models suggests that protein phosphorylation (catalysed by kinases and hydrolysed by phosphatases) might be dysregulated, making this major posttranslational modification a potential area of interest to find novel therapeutic targets. Furthermore, environmental enrichment (EE), used to model an active lifestyle in preclinical models, has been shown to alleviate Huntington’s disease-related motor and cognitive symptoms. However, the molecular mechanisms leading to these therapeutic effects are still largely unknown. In this study, we applied a phosphoproteomics approach combined with proteomic analyses on brain samples from pre-motor symptomatic R6/1 Huntington’s disease male mice (HD mice) and their wild-type (WT) littermates, after being housed either in EE conditions, or in standard housing (SH) conditions from 4 to 8 weeks of age (n=6 per group). We hypothesised that protein phosphorylation dysregulations occur prior to motor onset in this mouse model, in two highly affected brain regions, the striatum and hippocampus. Furthermore, we hypothesised that these phosphoproteome alterations are rescued by EE. When comparing 8-week-old HD mice and WT mice in SH conditions, our analysis revealed 229 differentially phosphorylated peptides in the striatum, compared to only 15 differentially phosphorylated peptides in the hippocampus (statistical thresholds FDR0.05, FC1.5). At the same disease stage, minor differences were found in protein expression, with 24 and 22 proteins dysregulated in the striatum and hippocampus, respectively. Notably, we found no differences in striatal protein phosphorylation and protein expression when comparing HD mice and their WT littermates in EE conditions. In the hippocampus, only four peptides were differentially phosphorylated between the two genotypes under EE conditions, and 22 proteins were differentially expressed. Together, our data indicates that protein phosphorylation dysregulations occur in the striatum of HD mice, prior to motor symptoms, and that the kinases and phosphatases leading to these changes in protein phosphorylation might be viable drug targets to consider for this disorder. Furthermore, we show that an early environmental intervention was able to rescue the changes observed in protein expression and phosphorylation in the striatum of HD mice and might underlie the beneficial effects of EE, thus identifying novel therapeutic targets.
2023-03-11 | PXD032205 | Pride
Project description:Humanized APOE genotypes influence lifespan independently of tau aggregation in the P301S mouse model of tauopathy
| PRJNA938486 | ENA
Project description:A loss of the checkpoint kinase ATM leads to impairments in the DNA damage response, and in humans causes cerebellar neurodegeneration, and a high risk to cancer. A loss of ATM is also associated with increased protein aggregation. The relevance and characteristics of this aggregation are still incompletely understood. Moreover, it is unclear to what extent other genotoxic conditions can trigger protein aggregation as well. Here, we show that targeting ATM, but also ATR or DNA topoisomerases result in a similar, widespread aggregation of a metastable, disease-associated subfraction of the proteome. Aggregation-prone model substrates, including expanded polyglutamine repeats, aggregate faster under these conditions. This increased aggregation results from an overload of chaperone systems, which lowers the cell-intrinsic threshold for proteins to aggregate. In line with this, we find that inhibition of the HSP70 chaperone system further exacerbates the increased protein aggregation. Moreover, we identify the molecular chaperone HSPB5 as a potent suppressor of it. Our findings reveal that various genotoxic conditions trigger protein aggregation, in a manner that is highly reminiscent of the widespread aggregation occurring in situations of proteotoxic stress and in proteinopathies.
2022-02-07 | GSE173940 | GEO
Project description:Reduced empathy and alexithymic traits are common across the autism spectrum, but it is unknown whether this is also true for intellectually advanced adults with autism spectrum disorder. The aim of this study was to examine whether college students with autism spectrum disorder experience difficulties with empathy and alexithymia, and whether this is associated with their cognitive levels of executive functioning. In total, 53 college students with autism spectrum disorder were compared to a gender-matched group of 29 neurotypical students on cognitive and affective dimensions of empathy and alexithymia. In addition, cognitive performance on executive functioning was measured with computerized and paper-and-pencil tasks. The autism spectrum disorder group scored significantly lower on cognitive empathy and higher on cognitive alexithymia (both d = 0.65). The difference on cognitive empathy also remained significant after controlling for levels of cognitive alexithymia. There were no group differences on affective empathy and alexithymia. No significant relations between executive functioning and cognitive alexithymia or cognitive empathy were detected. Together, these findings suggest that intellectually advanced individuals with autism spectrum disorder experience serious impairments in the cognitive processing of social-emotional information. However, these impairments cannot be attributed to individual levels of cognitive executive functioning.
| S-EPMC6625032 | biostudies-literature
Project description:Protein aggregation is a hallmark of many neurodegenerative diseases. In order to cope with misfolding and aggregation, cells have evolved an elaborate network of molecular chaperones, composed of different families. But while chaperoning mechanisms for different families are well established, functional and regulatory diversification within chaperone families is still largely a mystery. Here we decided to explore chaperone functional diversity, through the lens of pathological aggregation. We revealed that different naturally-occurring isoforms of DNAJ chaperones showed differential effects on different types of aggregates. We performed a chaperone screen for modulators of two neurodegeneration-related aggregating proteins, the Huntington’s disease-related HTT-polyQ, and the ALS-related mutant FUS (mutFUS). The screen identified known modulators of HTT-polyQ aggregation, confirming the validity of our approach. Surprisingly, modulators of mutFUS aggregation were completely different than those of HTT-polyQ. Interestingly, different naturally-occurring isoforms of DNAJ chaperones had opposing effects on HTT-polyQ vs. mutFUS aggregation. We identified a complex of the full length (FL) DNAJB14 and DNAJB12 isoforms which substantially alleviated mutFUS aggregation, in an HSP70-dependent manner. Their naturally occurring short isoforms were unable to form the complex, nor to interact with HSP70, and lost their ability to reduce mutFUS aggregation. In contrast, the short isoform of DNAJB12 significantly alleviated HTT-polyQ aggregation, while DNAJB12-FL aggravated HTT-polyQ aggregation. Finally, we demonstrated that full-length DNAJB14 ameliorated mutFUS aggregation compared to DNAJB14-short in primary neurons. Together, our data unraveled distinct molecular properties required for aggregation protection in different neurodegenerative diseases, and revealed a new layer of complexity of the chaperone network elicited by naturally occurring J-protein isoforms, highlighting functional diversity among the DNAJ family.
2021-12-07 | GSE165317 | GEO
Project description:Huntington’s disease (HD) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat in the Huntingtin (HTT) gene, encoding a homopolymeric polyglutamine (polyQ) tract. Although mutant HTT (mHTT) protein is known to aggregate, the links between aggregation and neurotoxicity remain unclear. Here we show that both translation and aggregation of wild-type and mHTT are regulated by a stress-responsive upstream open reading frame, and that polyQ expansions cause abortive translation termination and release of truncated, aggregation-prone mHTT fragments. Notably, we find that mHTT depletes translation elongation factor eIF5A in brains of symptomatic HD mice and cultured HD cells, leading to pervasive ribosome pausing and collisions. Loss of eIF5A disrupts homeostatic controls and impairs recovery from acute stress. Importantly, drugs that inhibit translation initiation reduce premature termination and mitigate this escalating cascade of ribotoxic stress and dysfunction in HD.
2024-03-13 | PXD026012 | Pride
Project description:Huntington’s disease(HD)is a hereditary neurodegenerative disorder that is caused by CAGexpansionsin the huntingtin(HTT)gene. Modelling HD in the lab has proven challenging asrodent models poorly reproduce the disease process and cellular models fail to include age-dependent processescrucial tothe disease. Here we generatedinduced neurons(iNs)throughdirect reprogrammingof fibroblastfrombothHD-patients and healthy controls. This procedureresultedin the generation ofpatient-derived HD neurons that retainedage-dependentcharacteristics. We found that HD-iNsconsistentlydisplayedshorterandfewerneuritescomparted to ctrl-iNsandthat thisphenotypecould be rescuedbyCRISPRi-mediated silencingof mHTT.Proteomics analysis demonstrated an alteration in AMPK-signalling and autophagyin HD-iNs. In line with this,HD-iNs displayeda distinctalteration inautophagy activity,characterizedby areduction in thetransportoflate autophagic structuresfrom neurites tothecell-bodyand subsequent cargo degradation.These results identify a novel therapeutic targetfor HD and provides a rational for futuredevelopmentof CRISPR-based approaches to treatHD
2022-07-22 | GSE182866 | GEO