Biology subjects

Djekidel, M. N.

Publications and source records attributed to Djekidel, M. N..

5 recordsLinked to original sources

bioRxiv2023

Phosphorylation of 53BP1 by ATM enforce neurodevelopmental programs in cortical organoids

53BP1 is a well-established DNA damage repair factor recently shown to regulate gene expression and critically influence tumor suppression and neural development. For gene regulation, how 53BP1 is regulated remains unclear. Here, we showed that 53BP1-serine 25 phosphorylation by ATM is required for neural progenitor cell proliferation and neuronal differentiation in cortical organoids. 53BP1-serine 25 phosphorylation dynamics controls 53BP1 target genes for neuronal differentiation and function, cellular response to stress, and apoptosis. Beyond 53BP1, ATM is required for phosphorylation of factors in neuronal differentiation, cytoskeleton, p53 regulation, and ATM, BNDF, and WNT signaling pathways for cortical organoid differentiation. Overall, our data suggest that 53BP1 and ATM control key genetic programs required for human cortical development.

developmental biology↗

bioRxiv2022

Understanding prefrontal cortex functions by decoding its molecular, cellular and circuit organization

The prefrontal cortex (PFC) is functionally one of the most complex regions of mammalian brain. Unlike other cortical areas that process single sensory modalities (like vision, touch, smell, etc.), the PFC integrates information across brain regions to regulate diverse functions ranging from cognition, emotion, executive action to even pain sensitivity. However, it is unclear how such diverse functions are organized at the cellular and circuit levels within the anatomical modules of the PFC. Here we employed spatially resolved single-cell transcriptome profiling to decode PFCs organizational heterogeneity. The results revealed that PFC has very distinct cell type composition relative to all neighboring cortical areas. Interestingly, PFC also adopts specialized transcriptional features, different from all neighbors, with differentially expressed genes regulating neuronal excitability. The projections to major subcortical targets of PFC emerge from combinations of neuron subclusters determined in a target-intrinsic fashion. These cellular and molecular features further segregated within subregions of PFC, alluding to the subregion-specific specialization of several PFC functions. Finally, using these unique cellular, molecular and projection properties, we identified distinct cell types and circuits in PFC that engage in pathogenesis of chronic pain. Collectively, we not only present a comprehensive organizational map of the PFC, critical for supporting its diverse functions, but also reveal the cluster and circuit identity of a pathway underlying chronic pain, a rapidly escalating healthcare challenge limited by molecular understanding of maladaptive PFC circuits. Major pointsO_LIPFC adopts unique cellular composition, distinct from other cortical areas C_LIO_LISelective transcriptomic features emerge in PFC to support its divergent functional portfolio C_LIO_LISubcortical projections of PFC assume target-intrinsic specification for innervating clusters C_LIO_LIA molecularly defined L5 projection neuron cluster (to PAG) potentially mediates chronic pain pathogenesis C_LI

neuroscience↗

bioRxiv2022

Snip1-PRC2 governs the intrinsic apoptosis program in the developing brain

Brain development requires the intricate balance between division, death, and differentiation of neural progenitor cells (NPCs). Here, we report the discovery of Snip1 as a key regulator of these NPC phases. The conditional deletion of Snip1 in the mouse embryonic brain causes dysplasia with robust induction of caspase 9-dependent apoptosis. In NPCs, Snip1 suppresses the genetic programs of apoptosis and developmental signaling pathways and promotes the genetic programs of cell cycle, neurogenesis, and cortical development. Mechanistically, Snip1 binds to the Polycomb complex PRC2, co-occupies gene targets with PRC2, and regulates H3K27 marks. Deletion of PRC2 is sufficient to reduce apoptosis and brain dysplasia and partially restore genetic programs and tissue development in the Snip1-depleted brain. Our findings suggest that Snip1 exerts loci-dependent regulation of PRC2 and H3K27me3 to toggle between cell fates in the developing brain.

developmental biology↗

bioRxiv2021

Decoding molecular and cellular heterogeneity of nucleus accumbens with high-throughput scRNA-seq and MERFISH

The nucleus accumbens (NAc) plays an important role in regulating multiple behaviors and its dysfunction has been linked to many neural disorders. However, the molecular, cellular and anatomic heterogeneity underlying its functional diversity remains incompletely understood. Here, we generate a cell census of the mouse NAc using high-throughput single cell RNA sequencing and multiplexed error-robust FISH, revealing a high level of cell heterogeneity in this brain region. We show that the transcriptional and spatial diversity of neuron subtypes underlie NAcs anatomic and functional heterogeneity, and possibly contribute to the pathogenesis of different neurological disorders. These findings explain how the seemingly simple neuronal composition of the NAc achieves its highly heterogenous structure and diverse functions. Collectively, our study generates a spatially resolved cell taxonomy for understanding the NAc structure and function, which demonstrates the importance of combining molecular and spatial information in revealing the fundamental features of the nervous system.

neuroscience↗

bioRxiv2021

CovidExpress: an interactive portal for intuitive investigation on SARS-CoV-2 related transcriptomes

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in humans could cause coronavirus disease 2019 (COVID-19). Since its first discovery in Dec 2019, SARS-CoV-2 has become a global pandemic and caused 3.3 million direct/indirect deaths (2021 May). Amongst the scientific communitys response to COVID-19, data sharing has emerged as an essential aspect of the combat against SARS-CoV-2. Despite the ever-growing studies about SARS-CoV-2 and COVID-19, to date, only a few databases were curated to enable access to gene expression data. Furthermore, these databases curated only a small set of data and do not provide easy access for investigators without computational skills to perform analyses. To fill this gap and advance open-access to the growing gene expression data on this deadly virus, we collected about 1,500 human bulk RNA-seq datasets from publicly available resources, developed a database and visualization tool, named CovidExpress (https://stjudecab.github.io/covidexpress). This open access database will allow research investigators to examine the gene expression in various tissues, cell lines, and their response to SARS-CoV-2 under different experimental conditions, accelerating the understanding of the etiology of this disease to inform the drug and vaccine development. Our integrative analysis of this big dataset highlights a set of commonly regulated genes in SARS-CoV-2 infected lung and Rhinovirus infected nasal tissues, including OASL that were under-studied in COVID-19 related reports. Our results also suggested a potential FURIN positive feedback loop that might explain the evolutional advantage of SARS-CoV-2.

bioinformatics↗