Expansion of outer cortical layer Cux2+ neurons required selective adaptations for DNA repair
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE314470 | GEO | 2026/02/02
REPOSITORIES: GEO
Similar Datasets
Project description:Neurodegeneration shows regional and cell-type-specific patterns in ageing and disease1, but the underlying mechanisms for cell type-specific neuronal losses remain poorly understood. Previous studies have shown upper cortical layer thinning in progressive human multiple sclerosis (MS) and that cortical layer 2/3 excitatory neurons (L2/3 ENs) that express CUT like homeobox 2 (CUX2) are selectively vulnerable to degeneration2. Here, we report that L2/3 ENs within MS cortical lesions have elevated DNA damage. DNA damage and selective loss of L2/3 ENs was recapitulated in diverse mouse models of demyelination and pan-cortical inflammation, confirming their intrinsic vulnerability. Functions of Cux2 and Activating transcription factor 4 (Atf4) were essential for resilience of L2/3 ENs during postnatal neuroinflammation, acting in neurons to enhance DNA double strand break repair. Interferon-γ, a cytokine implicated in MS pathogenesis3,4, was sufficient to elevate reactive oxygen species leading to DNA damage-mediated neuronal death in vitro and caused selective depletion of L2/3 neurons in mice. These findings indicate that DNA damage burden and inadequate repair in CUX2+ L2/3 ENs contributes to selective vulnerability in neuroinflammatory injury.
2026-02-02 | GSE314471 | GEO
Project description:Expansion of outer cortical layer Cux2+ neurons required selective adaptations for DNA repair
| PRJNA1391369 | ENA
Project description:Cell cycle deregulation leads to abnormal proliferation and cell death in a context-specific manner. Cell cycle progression driven via Rb pathway forces neurons to undergo S-phase, resulting in cell death associated with the progression of neuronal degeneration. Nevertheless, some Rb- and Rb family (Rb, p107, and p130)-deficient differentiating neurons can proliferate and form tumors. Here, we found that differentiating cerebral cortical excitatory neurons underwent S-phase progression but not cell division after acute Rb family inactivation in differentiating neurons. However, the differentiating neurons underwent cell division and form tumors when Rb family members were inactivated in cortical progenitors. Differentiating neurons generated from Rb -/-; p107 -/-; p130 -/- (Rb-TKO) progenitors, but not acutely inactivated Rb-TKO differentiating neurons, activated DNA double-strand break (DSB) repair pathway without increasing the tri-methylation of histone H4 at lysine 20 (H4K20M3), which is known to protect from DNA damage. The activation of DSB repair pathway was essential for the cell division of Rb-TKO differentiating neurons. These results suggest that newly-born cortical neurons from progenitors epigenetically become protected from DNA damage and cell division in a Rb family-dependent manner. 3 samples of pCAG-control, pCAG-RbTKO, pMAP2-control, and pMAP2-RbTKO cells
2014-01-01 | E-GEOD-37577 | biostudies-arrayexpress
Project description:Cell cycle deregulation leads to abnormal proliferation and cell death in a context-specific manner. Cell cycle progression driven via Rb pathway forces neurons to undergo S-phase, resulting in cell death associated with the progression of neuronal degeneration. Nevertheless, some Rb- and Rb family (Rb, p107, and p130)-deficient differentiating neurons can proliferate and form tumors. Here, we found that differentiating cerebral cortical excitatory neurons underwent S-phase progression but not cell division after acute Rb family inactivation in differentiating neurons. However, the differentiating neurons underwent cell division and form tumors when Rb family members were inactivated in cortical progenitors. Differentiating neurons generated from Rb -/-; p107 -/-; p130 -/- (Rb-TKO) progenitors, but not acutely inactivated Rb-TKO differentiating neurons, activated DNA double-strand break (DSB) repair pathway without increasing the tri-methylation of histone H4 at lysine 20 (H4K20M3), which is known to protect from DNA damage. The activation of DSB repair pathway was essential for the cell division of Rb-TKO differentiating neurons. These results suggest that newly-born cortical neurons from progenitors epigenetically become protected from DNA damage and cell division in a Rb family-dependent manner.
2014-01-01 | GSE37577 | GEO
Project description:Multiple DNA repair pathways collectively protect against DNA damage-induced replicative aging.
| PRJNA170083 | ENA
Project description:Plasma membrane damage-dependent senescence is a novel senescence subtype. Here, we compare the time-resolved proteomic profiles of plasma membrane damage-dependent senescence, DNA damage-dependent senescence, and replicative senescence to find the major differences between the senescence subtypes.
2024-12-20 | PXD047976 | JPOST Repository
Project description:Comprehensive Model Description
Overview
This model simulates the cellular response to DNA damage under conditions of ATM/ATR deficiency—such as in ataxia telangiectasia—and predicts the potential benefits of drug repositioning with Omaveloxolone and spermidine. It integrates several interconnected modules: DNA damage production and repair, ATM/ATR–p53 signaling, NRF2/KEAP1 regulation, spermidine-induced autophagy (with additional positive modulation of ATR signaling), and downstream p53 effectors involved in cell fate decisions.
1. DNA Damage Production and Repair Module
Basal DNA Damage Production:
DNA damage is continuously generated at a constant rate, representing both endogenous processes and low-level environmental stress. This reaction acts as a source term for the DNA_damage species.
Repair Pathways:
Several mechanisms work to reduce DNA damage:
ATM-Mediated Repair: Active ATM facilitates the direct repair of DNA damage.
ATR-Mediated Repair: Active ATR, in cooperation with CHK1, repairs DNA damage.
NRF2-Mediated Repair: Active NRF2 triggers antioxidant responses that reduce DNA damage.
Autophagy-Mediated Repair: The autophagy pathway, induced by spermidine, repairs DNA damage in a saturable manner (modeled using Michaelis–Menten kinetics). This ensures that even a significant pulse of damage is only partially repaired, leaving a nonzero steady-state level.
2. ATM/ATR–p53 Signaling Module
ATM and ATR Activation:
DNA damage, along with a positive input from TOPBP1, converts inactive ATM and ATR to their active forms. Under ATM/ATR-deficient conditions (as in ataxia telangiectasia), the activation is severely reduced, resulting in higher levels of unrepaired DNA damage.
p53 Activation:
Both ATM_active and ATR_active phosphorylate and activate p53. Active p53 then acts as a central integrator of the DNA damage signal.
Regulatory Proteins:
HDAC4:
HDAC4 cycles between inactive and active states. Its active form can attenuate p53 activity.
TOPBP1:
TOPBP1 is activated in a DNA damage–dependent manner and helps promote ATR activation.
CK2:
CK2 is a constitutively active kinase that supports TOPBP1 activation.
3. NRF2/KEAP1 Module and Omaveloxolone
NRF2 Activation:
DNA damage stimulates the conversion of NRF2_inactive to NRF2_active. Active NRF2 enhances antioxidant defenses and promotes DNA repair.
KEAP1-Mediated Degradation:
Under normal conditions, KEAP1 targets NRF2_inactive for degradation, keeping NRF2 activity low.
Modulation by Omaveloxolone:
Omaveloxolone is modeled as a constant (boundary) species. It inhibits KEAP1’s activity, thereby reducing NRF2 degradation. This shifts the balance in favor of increased NRF2_active, which boosts the cell’s antioxidant and repair responses.
4. Spermidine-Induced Autophagy and Positive Modulation of ATR Signaling
Spermidine is modeled as a constant species and has two major effects:
Induction of Autophagy:
Spermidine promotes the conversion of Autophagy_inactive to Autophagy_active. The active autophagy machinery repairs DNA damage using a saturable (Michaelis–Menten) mechanism. This pathway helps clear DNA damage but is limited by its maximum capacity.
Enhancement of ATR Signaling:
Spermidine also positively modulates ATR signaling by enhancing the CK2-mediated activation of TOPBP1. In the model, the effective rate of TOPBP1 activation is increased proportionally to the concentration of spermidine. This is represented by a modulation factor, where the effective rate constant for TOPBP1 activation is multiplied by a term that increases with spermidine concentration. The boosted TOPBP1_active level in turn enhances ATR activation, partially compensating for the loss of ATM/ATR function.
5. Downstream p53 Targets: Cell Fate Decisions
Activated p53 regulates cell fate by inducing the production of several downstream effectors:
p21:
p21 is produced in response to p53 activation and is associated with cell cycle arrest and senescence. Its production is balanced by a degradation reaction.
BAX and PUMA:
Both BAX and PUMA are pro-apoptotic proteins. They are produced in proportion to p53_active and are subsequently degraded. Their relative levels help determine whether the cell will undergo apoptosis.
6. Reaction Kinetics (Qualitative Overview)
Mass-Action and Michaelis–Menten Kinetics:
Most reactions in the model are governed by mass-action kinetics. For example, activation and deactivation reactions (such as ATM activation by DNA damage or p53 activation by ATM/ATR) follow simple proportional relationships.
Saturable Repair Processes:
The autophagy-mediated DNA repair reaction uses Michaelis–Menten kinetics to reflect a saturation effect; when DNA damage is high, the repair rate approaches a maximum value, ensuring that not all damage is cleared immediately.
Modulatory Effects:
Spermidine increases the effective rate of TOPBP1 activation (and hence ATR activation) via a modulation term that is proportional to its concentration. Omaveloxolone reduces the degradation rate of NRF2 by inhibiting KEAP1.
Biological Implications and Model Utility
ATM/ATR Deficiency:
In ataxia telangiectasia, ATM/ATR functions are diminished, leading to increased DNA damage. The model simulates this scenario and examines how alternative pathways (NRF2-mediated repair, autophagy, and enhanced ATR signaling via spermidine) help mitigate the damage.
Drug Repositioning Predictions:
The model can be used to predict the outcomes of repositioning drugs:
Omaveloxolone is expected to stabilize NRF2, enhancing antioxidant defenses and reducing DNA damage.
Spermidine acts dually by promoting autophagy (with a saturable repair capacity) and by boosting ATR signaling via TOPBP1 activation.
Cell Fate Outcomes:
The downstream p53 targets (p21, BAX, and PUMA) serve as markers for cell cycle arrest/senescence and apoptosis. By simulating the dynamics of these proteins, the model can predict whether a cell is likely to survive, arrest its cycle, or undergo apoptosis based on the integrated response to DNA damage and drug interventions.
Conclusion
This detailed and comprehensive model integrates multiple layers of the cellular response to DNA damage in ATM/ATR-deficient conditions. It includes upstream damage sensing, multiple repair pathways (including direct kinase-mediated repair, antioxidant responses via NRF2, and autophagy-mediated repair), and downstream effectors that determine cell fate. Omaveloxolone and spermidine are modeled to specifically modulate the NRF2/KEAP1 pathway and ATR signaling (via TOPBP1 activation), respectively. This framework provides a robust platform for exploring drug repositioning strategies and predicting cellular outcomes in diseases such as ataxia telangiectasia.
2025-11-25 | MODEL2503190002 | BioModels
Project description:Cortical development is under control of transcriptional programs that are orchestrated by activation of key determinants such as transcription factors. But stable inheritance of temporo-spatial activity of factors influencing cell fate and regionalization in different layers is only partly understood. We report that chromatin methylation at H3K79 transmits cell fate and layering information from early to late progenitors. Activity of DOT1L, mediating H3K79 methylation, prevents premature cell cycle exit by increasing expression of genes regulating asymmetric cell division (Vangl2, Cenpj). Transcriptional programs characteristic for upper layer neurons are less active in Dot1l-deficient mice already at developmental stages that precede upper layer neuron generation. DOT1L activates expression of many key determinants such as Cux1, Cux2, Satb2 or Pou3f3. Additionally, DOT1L affects transcription of Sox family members, suggesting an evolutionary conserved mechanism. In part, DOT1L and H3K79me2 replace inactivating H3K9me3 at Sox family promoters and allow for transcriptional activation during neural differentiation.
2017-12-31 | GSE95833 | GEO
Project description:Cortical development is under control of transcriptional programs that are orchestrated by activation of key determinants such as transcription factors. But stable inheritance of temporo-spatial activity of factors influencing cell fate and regionalization in different layers is only partly understood. We report that chromatin methylation at H3K79 transmits cell fate and layering information from early to late progenitors. Activity of DOT1L, mediating H3K79 methylation, prevents premature cell cycle exit by increasing expression of genes regulating asymmetric cell division (Vangl2, Cenpj). Transcriptional programs characteristic for upper layer neurons are less active in Dot1l-deficient mice already at developmental stages that precede upper layer neuron generation. DOT1L activates expression of many key determinants such as Cux1, Cux2, Satb2 or Pou3f3. Additionally, DOT1L affects transcription of Sox family members, suggesting an evolutionary conserved mechanism. In part, DOT1L and H3K79me2 replace inactivating H3K9me3 at Sox family promoters and allow for transcriptional activation during neural differentiation.
2017-12-31 | GSE95832 | GEO
Project description:Cortical development is under control of transcriptional programs that are orchestrated by activation of key determinants such as transcription factors. But stable inheritance of temporo-spatial activity of factors influencing cell fate and regionalization in different layers is only partly understood. We report that chromatin methylation at H3K79 transmits cell fate and layering information from early to late progenitors. Activity of DOT1L, mediating H3K79 methylation, prevents premature cell cycle exit by increasing expression of genes regulating asymmetric cell division (Vangl2, Cenpj). Transcriptional programs characteristic for upper layer neurons are less active in Dot1l-deficient mice already at developmental stages that precede upper layer neuron generation. DOT1L activates expression of many key determinants such as Cux1, Cux2, Satb2 or Pou3f3. Additionally, DOT1L affects transcription of Sox family members, suggesting an evolutionary conserved mechanism. In part, DOT1L and H3K79me2 replace inactivating H3K9me3 at Sox family promoters and allow for transcriptional activation during neural differentiation.
2017-12-31 | GSE95831 | GEO