Neuronal deletion of the circadian clock gene Bmal1 induces cell-autonomous dopaminergic neurodegeneration
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ABSTRACT:
PROVIDER: PRJNA1006712 | ENA |
REPOSITORIES: ENA
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Project description:Circadian rhythm dysfunction is a hallmark of Parkinson Disease (PD), and diminished expression of the core clock gene Bmal1 has been described in PD patients. BMAL1 is required for core circadian clock function, but also serves non-rhythmic functions. Germline Bmal1 deletion can cause brain oxidative stress and synapse loss in mice, and can exacerbate dopaminergic neurodegeneration in response to MPTP. Here we examined the impact of cell type-specific Bmal1 deletion on dopaminergic neuron viability in vivo. We observed that global, post-natal deletion of Bmal1 caused spontaneous loss of tyrosine hydroxylase-positive (TH+) dopaminergic neurons in the substantia nigra pars compacta (SNpc). This was not due to disruption of behavioral circadian rhythms, and was not induced by astrocyte- or microglia-specific Bmal1 deletion. However, either pan-neuronal or TH neuron-specific Bmal1 deletion caused cell-autonomous loss of TH+ neurons in the SNpc. Finally, global Bmal1 deletion exacerbated TH+ neuron loss following injection of alpha-synclein fibrils. Transcriptomic analysis of neuron-specific Bmal1 KO brain revealed dysregulation of pathways involved in oxidative phosphorylation and Parkinson Disease.
2023-08-18 | GSE241200 | GEO
Project description:In mammals, circadian clocks are strictly suppressed during early embryonic stages as well as pluripotent stem cells, by the lack of CLOCK/BMAL1 mediated circadian feedback loops. During ontogenesis, the innate circadian clocks emerge gradually at a late developmental stage, then, with which the circadian temporal order is invested in each cell level throughout a body. Meanwhile, in the early developmental stage, a segmented body plan is essential for an intact developmental process and somitogenesis is controlled by another cell-autonomous oscillator, the segmentation clock, in the posterior presomitic mesoderm (PSM). In the present study, focusing upon the interaction between circadian key components and the segmentation clock, we investigated the effect of the CLOCK/BMAL1 on the segmentation clock Hes7 oscillation, revealing that the expression of functional CLOCK/BMAL1 severely interferes with the ultradian rhythm of segmentation clock in induced PSM and gastruloids. RNA sequencing analysis showed that the premature expression of CLOCK/BMAL1 affects the Hes7 transcription and its regulatory pathways. These results suggest that the suppression of CLOCK/BMAL1-mediated transcriptional regulation during the somitogenesis may be inevitable for intact mammalian development.
2021-12-09 | GSE181295 | 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;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:Circadian rhythm dysfunction is a hallmark of Parkinson disease (PD), and diminished expression of the core clock gene Bmal1 has been described in patients with PD. BMAL1 is required for core circadian clock function but also serves nonrhythmic functions. Germline Bmal1 deletion can cause brain oxidative stress and synapse loss in mice, and it can exacerbate dopaminergic neurodegeneration in response to the toxin MPTP. Here we examined the effect of cell type-specific Bmal1 deletion on dopaminergic neuron viability in vivo. We observed that global, postnatal deletion of Bmal1 caused spontaneous loss of tyrosine hydroxylase+ (TH+) dopaminergic neurons in the substantia nigra pars compacta (SNpc). This was not replicated by light-induced disruption of behavioral circadian rhythms and was not induced by astrocyte- or microglia-specific Bmal1 deletion. However, either pan-neuronal or TH neuron-specific Bmal1 deletion caused cell-autonomous loss of TH+ neurons in the SNpc. Bmal1 deletion did not change the percentage of TH neuron loss after α-synuclein fibril injection, though Bmal1-KO mice had fewer TH neurons at baseline. Transcriptomics analysis revealed dysregulation of pathways involved in oxidative phosphorylation and Parkinson disease. These findings demonstrate a cell-autonomous role for BMAL1 in regulating dopaminergic neuronal survival and may have important implications for neuroprotection in PD.
| S-EPMC10906231 | biostudies-literature
Project description:The diurnal variation in acetaminophen (APAP) hepatotoxicity (“chronotoxicity”) is thought to be due to oscillations in xenobiotic metabolism that are influenced by the circadian phases of feeding or fasting. Because of APAP’s relevance to human poisoning, we set out to determine the relative contributions of the central clock in the SCN and the autonomous clock in the hepatocyte in modulating the chronotoxicity of APAP. Using a conditional null allele of Mop3 (ArntL, Bmal1) we are able to delete the clock from hepatocytes while keeping the central and other peripheral clocks intact (eg, those controlling food intake). Our data from this hepatocyte-null mouse model suggests that, while the central circadian clock modulates some detoxification pathways indirectly by driving activity patterns and feeding rhythms, the autonomous hepatocyte circadian clock controls major aspects of APAP bioactivation independent of feeding rhythms.
2013-08-30 | GSE34442 | GEO
Project description:Disruption of local iron homeostasis is a common feature of neurodegenerative diseases. We focused on dopaminergic neurons, asking how iron transport proteins modulate iron homeostasis in vivo. Inactivation of the transmembrane iron exporter ferroportin had no apparent consequences. However, loss of the transferrin receptor 1, involved in iron uptake, caused profound, age-progressive neurodegeneration with features similar to Parkinson’s disease. There was gradual loss of dopaminergic projections in the striatum with subsequent death of dopaminergic neurons in the substantia nigra. After depletion of 30% of the neurons the mice developed neurobehavioral parkinsonism, with evidence of mitochondrial dysfunction and impaired mitochondrial autophagy. Molecular analysis revealed strong signatures indicative of attempted axonal regeneration, a metabolic switch to glycolysis and the unfolded protein response. We speculate that cellular iron deficiency may contribute to neurodegeneration in human patients Using Ribotag technology, from mouse ventral midbrain lysates, we isolated actively translated mRNA species from control and Transferrin receptor 1-null dopaminergic neurons. Two mouse ages were used 3 wks (early neurodegeration) 10 wks (late neurodegeneration)
2015-03-11 | E-GEOD-66730 | biostudies-arrayexpress
Project description:The diurnal variation in acetaminophen (APAP) hepatotoxicity (“chronotoxicity”) is thought to be due to oscillations in xenobiotic metabolism that are influenced by the circadian phases of feeding or fasting. Because of APAP’s relevance to human poisoning, we set out to determine the relative contributions of the central clock in the SCN and the autonomous clock in the hepatocyte in modulating the chronotoxicity of APAP. Using a conditional null allele of Mop3 (ArntL, Bmal1) we are able to delete the clock from hepatocytes while keeping the central and other peripheral clocks intact (eg, those controlling food intake). Our data from this hepatocyte-null mouse model suggests that, while the central circadian clock modulates some detoxification pathways indirectly by driving activity patterns and feeding rhythms, the autonomous hepatocyte circadian clock controls major aspects of APAP bioactivation independent of feeding rhythms, possibly through transcriptional regulation of cytochrome p450-oxidoreductase (Por).
2013-08-30 | GSE34443 | GEO
Project description:The diurnal variation in acetaminophen (APAP) hepatotoxicity (“chronotoxicity”) is thought to be due to oscillations in xenobiotic metabolism that are influenced by the circadian phases of feeding or fasting. Because of APAP’s relevance to human poisoning, we set out to determine the relative contributions of the central clock in the SCN and the autonomous clock in the hepatocyte in modulating the chronotoxicity of APAP. Using a conditional null allele of Mop3 (ArntL, Bmal1) we are able to delete the clock from hepatocytes while keeping the central and other peripheral clocks intact (eg, those controlling food intake). Our data from this hepatocyte-null mouse model suggests that, while the central circadian clock modulates some detoxification pathways indirectly by driving activity patterns and feeding rhythms, the autonomous hepatocyte circadian clock controls major aspects of APAP bioactivation independent of feeding rhythms, possibly through transcriptional regulation of cytochrome p450-oxidoreductase (Por). 10-20 week old Mop3fxfx mice positive or negative for Cre-recombinase driven by the albumin promoter, housed in 12 hour light:12 dark, ad lib feeding and drinking conditions were sacrificed every four hours over two separte days beginning at ZT0. A two color, reference design experiment in which kidney RNA from at least 3 mice per timepoint were pooled and labeled with Cy3 and hybridized according to Agilent protocols against a reference pool of RNA madeup from respective tissue taken from 10 week Mop3fxfx and Mop3fxfxCreAlb mice which was labeled with Cy5.
2013-08-30 | E-GEOD-34443 | biostudies-arrayexpress
Project description:The diurnal variation in acetaminophen (APAP) hepatotoxicity (“chronotoxicity”) is thought to be due to oscillations in xenobiotic metabolism that are influenced by the circadian phases of feeding or fasting. Because of APAP’s relevance to human poisoning, we set out to determine the relative contributions of the central clock in the SCN and the autonomous clock in the hepatocyte in modulating the chronotoxicity of APAP. Using a conditional null allele of Mop3 (ArntL, Bmal1) we are able to delete the clock from hepatocytes while keeping the central and other peripheral clocks intact (eg, those controlling food intake). Our data from this hepatocyte-null mouse model suggests that, while the central circadian clock modulates some detoxification pathways indirectly by driving activity patterns and feeding rhythms, the autonomous hepatocyte circadian clock controls major aspects of APAP bioactivation independent of feeding rhythms. 10-20 week old Mop3fxfx mice positive or negative for Cre-recombinase driven by the albumin promoter, housed in 12 hour light:12 dark, ad lib feeding and drinking conditions were sacrificed every four hours over two separte days beginning at ZT0. A two color, reference design experiment in which liver RNA from at least 3 mice per timepoint were pooled and labeled with Cy3 and hybridized according to Agilent protocols against a reference pool of RNA madeup from respective tissue taken from 10 week Mop3fxfx and Mop3fxfxCreAlb mice which was labeled with Cy5.
2013-08-30 | E-GEOD-34442 | biostudies-arrayexpress
Project description:The mammalian circadian clock is a molecular oscillator composed of a feedback loop that involves transcriptional activators CLOCK and BMAL1, and repressors Cryptochrome (CRY) and Period (PER). Here we show that a direct CLOCK-BMAL1 target gene, Gm129, is a novel regulator of the feedback loop. ChIP analysis revealed that the CLOCK:BMAL1:CRY1 complex strongly occupies the promoter region of Gm129. Both mRNA and protein levels of GM129 exhibit high amplitude circadian oscillations in mouse liver, and Gm129 gene encodes a nuclear-localized protein that directly interacts with BMAL1 and represses CLOCK:BMAL1 activity. In vitro and in vivo protein-DNA interaction results demonstrate that, like CRY1, GM129 functions as a repressor by binding to the CLOCK:BMAL1 complex on DNA. Although Gm129-/- or Cry1-/- Gm129-/- mice retain a robust circadian rhythm, the peaks of Nr1d1 and Dbp mRNAs in liver exhibit significant phase delay compared to control. Our results suggest that, in addition to CRYs and PERs, GM129 protein contributes to the transcriptional feedback loop by modulating CLOCK:BMAL1 activity as a transcriptional repressor. Examination of 3 transcriptional regulators in mouse liver
2014-01-07 | E-GEOD-53828 | biostudies-arrayexpress