Astrocytes deficient in circadian clock gene Bmal1 show enhanced activation responses to amyloid-beta pathology without changing plaque burden
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ABSTRACT:
PROVIDER: PRJNA942993 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR23795102_1.fastq.gz | Fastqsanger.gz | |||
| SRR23795102_2.fastq.gz | Fastqsanger.gz | |||
| SRR23795103_1.fastq.gz | Fastqsanger.gz | |||
| SRR23795103_2.fastq.gz | Fastqsanger.gz | |||
| SRR23795104_1.fastq.gz | Fastqsanger.gz |
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Project description:An emerging link between circadian clock function and neurodegeneration has indicated a critical role for the molecular clock in brain health. We previously reported that deletion of the core circadian clock gene Bmal1 abrogates clock function and induces cell-autonomous astrocyte activation. Regulation of astrocyte activation has important implications for protein aggregation, inflammation, and neuronal survival in neurodegenerative conditions such as Alzheimer's disease (AD). Here, we investigated how astrocyte activation induced by Bmal1 deletion regulates astrocyte gene expression, amyloid-beta (Aβ) plaque-associated activation, and plaque deposition. To address these questions, we crossed astrocyte-specific Bmal1 knockout mice (Aldh1l1-CreERT2;Bmal1(fl/fl), termed BMAL1 aKO), to the APP/PS1-21 and the APP(NL-G-F) models of Aβ accumulation. Transcriptomic profiling showed that BMAL1 aKO induced a unique transcriptional profile affecting genes involved in both the generation and elimination of Aβ. BMAL1 aKO mice showed exacerbated astrocyte activation around Aβ plaques and altered gene expression. However, this astrogliosis did not affect plaque accumulation or neuronal dystrophy in either model. Our results demonstrate that the striking astrocyte activation induced by Bmal1 knockout does not influence Aβ deposition, which indicates that the effect of astrocyte activation on plaque pathology in general is highly dependent on the molecular mechanism of activation.
2023-03-14 | GSE227063 | GEO
Project description:An emerging link between circadian clock function and neurodegeneration has indicated a critical role for the molecular clock in brain health. We previously reported that deletion of the core circadian clock gene Bmal1 abrogates clock function and induces cell-autonomous astrocyte activation. Regulation of astrocyte activation has important implications for protein aggregation, inflammation, and neuronal survival in neurodegenerative conditions such as Alzheimer's disease (AD). Here, we investigated how astrocyte activation induced by Bmal1 deletion regulates astrocyte gene expression, amyloid-beta (Aβ) plaque-associated activation, and plaque deposition. To address these questions, we crossed astrocyte-specific Bmal1 knockout mice (Aldh1l1-CreERT2;Bmal1fl/fl, termed BMAL1 aKO), to the APP/PS1-21 and the APPNL-G-F models of Aβ accumulation. Transcriptomic profiling showed that BMAL1 aKO induced a unique transcriptional profile affecting genes involved in both the generation and elimination of Aβ. BMAL1 aKO mice showed exacerbated astrocyte activation around Aβ plaques and altered gene expression. However, this astrogliosis did not affect plaque accumulation or neuronal dystrophy in either model. Our results demonstrate that the striking astrocyte activation induced by Bmal1 knockout does not influence Aβ deposition, which indicates that the effect of astrocyte activation on plaque pathology in general is highly dependent on the molecular mechanism of activation.
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Project description:SUMOylation is a post-translational protein modification that consists of the attachment of a SUMO (small ubiquitin-related modifier) moiety to a lysine residue of a target protein. Alteration in protein SUMOylation has been linked to the amyloid pathology apparent in Alzheimer’s disease. In the present work, we aimed to elucidate the role of protein SUMOylation during aging and increased amyloid burden in vivo using a His6-HA-SUMO1 knock-in mouse in the 5XFAD model of Alzheimer’s disease. We performed anti-HA based affinity purification from young (8 weeks) and old (36 weeks) mouse brains, followed by label-free quantification of purified proteins by LC-MS. Interestingly, we did not observe any alteration in the levels of SUMO1 conjugation related to Alzheimer’s disease, but found age-related alterations in global levels of SUMO1 conjugation. The identified SUMO1 candidate substrates are dominantly nuclear proteins, mainly involved in RNA processing. Our findings open novel directions of research for studying a functional link between SUMOylation and its role in guarding nuclear functions during aging.
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Project description:Alzheimer’s disease (AD) is the most common age-related dementia. Lifestyle factors, including alcohol use, can increase the risk of AD. While human studies demonstrate that alcohol use can negatively impact AD risk and disease progression, the underlying alcohol-dependent mechanisms that increase Aβ burden and impair cognition remain elusive. We have recently shown that alcohol (ethanol) can acutely affect microglial dynamics, which are critical to microglial function, and many other studies have reported inflammatory activation of microglia after long-term alcohol exposure in both humans and animal models. Here, we administered 4 weeks of ethanol at dosages that mimic human binge drinking to 2.5-month-old male 5xFAD mice, a common mouse model of AD. After a two-week abstinence period, we performed behavior assays and analyzed amyloid pathology and microglial transcriptome in the hippocampus and morphology in the subiculum where amyloid pathology develops earlier than in other brain regions. We found that ethanol exposure facilitated amyloid pathology and worsened cognitive function in 5xFAD mice, while microglial transcriptomic landscape, arborization and phagocytosis appeared unchanged. Overall, our results suggest that pronounced ethanol exposure, when started early in the disease before amyloid pathology is established, can worsen AD progression in an amyloidosis model.
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Project description:TMT analysis of proteomic changes in the gastrocnemius skeletal muscles of WT and Bmal1-KO mice, and Bmal1-KO mice rescued with AAV-mediated muscle-specific expression of Bmal1.
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Project description:In this study, we combined cell-specific laser capture and RNA-seq analysis to investigate transcriptome changes in both amyloid-ß plaque-associated and plaque-distant microglia at different stages of the disease.
2022-09-28 | GSE205048 | GEO
Project description:Treatment strategies that are efficient against established Alzheimer's disease (AD) are needed. BRICHOS is a molecular chaperone domain that prevents amyloid fibril formation and associated cellular toxicity. In this study, we treated an AD mouse model seven months after pathology onset, using intravenous administration of recombinant human (rh) Bri2 BRICHOS R221E. Two injections of rh Bri2 BRICHOS R221E per week for three months in AD mice reduced amyloid b (Ab) burden, and mitigated astro- and microgliosis, as determined by glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba1) immunohistochemistry. Sequencing of RNA from cortical microglia cells showed that BRICHOS treatment normalized expression of identified plaque-induced genes in mice and humans, including clusterin and GFAP. Rh Bri2 BRICHOS R221E passed the blood-brain barrier (BBB) in age-matched wildtype mice as efficiently as in the AD mice, but then had no effect on measures of AD-like pathology, and mainly affected the expression of genes involved in cellular shape and movement. These results indicate a potential of rh Bri2 BRICHOS against advanced AD and underscore the ability of BRICHOS to target amyloid-induced pathology.
2024-09-25 | GSE263166 | GEO
Project description:To define regulation of tissue proteomes by Bmal1, daily feeding rhythm, and the interaction, we employed Bmal1-stopFL mice, which do not express the main transcriptional activator of the molecular clock, Bmal1, except in cre recombinase-expressing cells1,2 (Figure 1A). Bmal1-stopFL mice lacking cre (Bmal1 knockout, KO) are analogous to Bmal1-null mice and display severely impaired behavioral and molecular rhythms1-3. Hepatocyte-specific Alfp-cre and skeletal muscle-specific Hsa-cre genes were introduced to generate a single line wherein both hepatocyte and skeletal muscle Bmal1 were reconstituted (Liver+Muscle-RE), i.e., rescued (Smith, Koronowski et al. 2023). This approach had the benefit of analyzing liver and muscle from the same mice but comes with the qualification that the abundance of some proteins may be influenced by Bmal1 function in the other tissue, or by a synergistic effect of Bmal1 in both tissues, rather than through rescue of local Bmal1 function alone. Proteomic anlaysis was performed in liver and skeletal muscle.
2024-01-26 | PXD040362 | Pride
Project description:Advances in circadian research revealed an intricate relationship between aging and circadian rhythms. However, whether and how the circadian machinery contribute to stem cell aging, especially in primates, remains poorly understood. In this study, we investigated the role of BMAL1, the only non-redundant circadian clock component, during aging in mesenchymal progenitor cells (MPCs). We observed an accelerated aging phenotype in both BMAL1 deficient human and cynomolgus monkey MPCs. Notably, this phenotype is mainly attributed to a transcriptional-independent role of BMAL1 in stabilizing the heterochromatin and thus preventing LINE1 activation. In senescent MPCs from human and cynomolgus monkeys, dampened LINE1 binding capacity of BMAL1 and synergistically activated LINE1 transcripts were observed. Furthermore, similar de-stabilized heterochromatin and aberrant LINE1s transcription was observed in the skin and muscle tissues from BMAL1-deficient cynomolgus monkey. Altogether, these findings uncover a noncanonical role of BMAL1 in stabilizing heterochromatin to inactivate LINE1 that drives aging in primates.
2022-03-18 | PXD030570 | Pride
Project description:Neuroinflammation is thought to contribute to the pathogenesis of Alzheimer’s disease (AD), yet numerous studies have demonstrated a beneficial role for neuroinflammation in amyloid plaque clearance. We have previously shown that sustained expression of IL-1β in the hippocampus of APP/PS1 mice decreases amyloid plaque burden independent of recruited CCR2+ myeloid cells, suggesting resident microglia as the main phagocytic effectors of IL-1β-induced plaque clearance. To date, however, the mechanisms of IL-1β-induced plaque clearance remain poorly understood. To determine whether IL-1β-induced plaque clearance is due to enhanced microglial phagocytosis of Aβ, APP/PS1 mice induced to express mature human IL-1β in the hippocampus via adenoviral transduction were treated with the Aβ fluorescent probe methoxy-X04 (MX04) and microglial internalization of Aβ was analyzed by flow cytometry and immunohistochemistry. We found that resident microglia (CD45loCD11b+) constituted >70% of the MX04+ cells in both control and IL-1β-treated conditions, and that <10% of MX04+ cells were recruited myeloid cells (CD45hiCD11b+). However, we found that IL-1β treatment did not augment the percentage of MX04+ microglia nor the quantity of Aβ internalized by individual microglia. Instead, we found that IL-1β treatment resulted in a significant increase in the total number of MX04+ microglia in the hippocampus due to IL-1β-induced proliferation. Consistent with these results, transcriptomic analyses revealed very similar gene expression profiles between MX04+ and MX04- microglia, indicating IL-1β does not drive enhanced expression of phagocytosis-related genes. By contrast, IL-1β treatment was associated with large-scale changes in the expression of genes related to proliferation, immune function and inflammation. Together, these studies demonstrate that IL-1β induces microglial proliferation and the expression of genes involved in inflammatory immune functions that may be related to Aβ clearance.
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