Biology subjects

Lowe, C. C.

Publications and source records attributed to Lowe, C. C..

4 recordsLinked to original sources

bioRxiv2023

Sustained Generation of Neurons Destined for Neocortex with Oxidative Metabolic Upregulation upon Filamin Abrogation

Neurons in the neocortex are generated during embryonic development. While the adult ventricular-subventricular zone (V-SVZ) contains cells with neural stem/progenitors characteristics, it remains unclear whether it has the capacity of producing neocortical neurons. Here we show that the generation of neurons exhibiting transcriptomic resemblance to neurons of the upper cortical layers continues in the V-SVZ of mouse models of a human condition known as periventricular heterotopia by abrogating filamin. We found such surplus neurogenesis was associated with V-SVZs transcriptional upregulation of oxidative phosphorylation, mitochondrial biogenesis, and increased vascularization. Our spatial transcriptomics analysis also showed that the neurogenic activation of V-SVZ was coupled with enriched expression of genes in diverse pathways for energetics, signaling, neuronal activities, and metabolic turnovers of nucleic acids and proteins in upper cortical layers. These findings support the potential of generating neocortical neurons in adulthood through enhancing brain-wide vascular circulation, aerobic ATP synthesis, and neuronal vitality.

neuroscience↗

bioRxiv2023

Senescence of cortical neurons following persistent DNA double-strand breaks induces cerebrovascular lesions

DNA double strand breaks (DSBs), neuroinflammation, and vascular alterations in the brain are all associated with neurodegenerative disorders. However, the interconnections between these neuropathological changes and how they act synergistically to promote irreversible neurodegeneration remain unclear. Here we show that abrogating the BRCA1-associated protein Brap in cerebral cortical neurons, as opposed to vascular endothelium cells, causes cerebrovascular defects. This non-cell autonomous effect is mediated by cellular senescence resulting from persistent neuronal DSBs. We show that in the state of senescence, there is a massive upregulation of genes involved in cell secretion, inflammatory responses, and vascular changes, which coincides with cerebral microclots and microbleeds. The vascular lesions intertwine with neuroinflammation and exacerbate neuronal DSBs, culminating in oxidative stress, metabolic alteration, and downregulation of genes essential for neuronal function. By demonstrating the cerebrovascular impact of cortical neuronal DSBs, our data suggest that senescence-associated secretory phenotype can initiate brain-wide neurodegeneration.

neuroscience↗

bioRxiv2021

Nde1 is Required for Heterochromatin Compaction and Stability in Neocortical Neurons

The NDE1 gene encodes a scaffold protein essential for brain development. While biallelic NDE1 loss of function (LOF) causes microcephaly with profound mental retardation, NDE1 missense mutations and copy number variations are associated with multiple neuropsychiatric disorders. However, the etiology of the diverse phenotypes resulting from NDE1 aberrations remains elusive. Here we show Nde1 controls neurogenesis through facilitating heterochromatin compaction via histone H4K20 trimethylation. This mechanism patterns diverse chromatin landscapes and stabilizes constitutive heterochromatin of neocortical neurons. We show NDE1 undergoes dynamic liquid-liquid phase separation, partitioning to the nucleus and interacting with pericentromeric and centromeric satellite repeats. Nde1 LOF results in nuclear architecture aberrations and DNA double strand breaks, as well as instability and derepression of pericentromeric satellite repeats in neocortical neurons. These findings uncover a pivotal role of NDE1/Nde1 in establishing and maintaining neuronal heterochromatin. They suggest that heterochromatin impairments underlie a wide range of brain dysfunction.

genetics↗

bioRxiv2020

Histone H2A ubiquitination resulting from Brap loss of function connects multiple aging hallmarks and accelerates neurodegeneration

Aging is an intricate process that is characterized by multiple hallmarks including stem cell exhaustion, genome instability, epigenome alteration, impaired proteostasis, and cellular senescence. While each of these traits is detrimental at the cellular level, it remains unclear how they are interconnected to cause systemic organ deterioration. Here we show that abrogating Brap, a BRCA1 associated protein important for neurogenesis, results in cellular senescence with persistent DNA double-strand breaks and elevation of histone H2A mono- and poly-ubiquitination (H2Aub). The high H2Aub initiates histone proteolysis, leading to both epigenetic alteration and proteasome overflow. These defects induce neuroinflammation, impair proteostasis, accelerate neurodegeneration, and substantially shorten lifespan in mice carrying Brap deletions in the brain. We further show H2Aub is also increased in human brain tissues of Alzheimers disease. These data together suggest that chromatin aberrations mediated by H2Aub act as a nexus of multiple aging hallmarks and promote tissue-wide degeneration.

neuroscience↗