scholarly journals LPA signaling acts as a cell-extrinsic mechanism to initiate cilia disassembly and promote neurogenesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Huai-Bin Hu ◽  
Zeng-Qing Song ◽  
Guang-Ping Song ◽  
Sen Li ◽  
Hai-Qing Tu ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Neural Progenitor Cells ◽  
Regulatory Mechanisms ◽  
Systematic Analysis ◽  
Lpa Receptor ◽  
Genetic Inactivation ◽  
Dynamic Assembly ◽  
A Cell ◽  
Extracellular Factor ◽  
Serum Components

AbstractDynamic assembly and disassembly of primary cilia controls embryonic development and tissue homeostasis. Dysregulation of ciliogenesis causes human developmental diseases termed ciliopathies. Cell-intrinsic regulatory mechanisms of cilia disassembly have been well-studied. The extracellular cues controlling cilia disassembly remain elusive, however. Here, we show that lysophosphatidic acid (LPA), a multifunctional bioactive phospholipid, acts as a physiological extracellular factor to initiate cilia disassembly and promote neurogenesis. Through systematic analysis of serum components, we identify a small molecular—LPA as the major driver of cilia disassembly. Genetic inactivation and pharmacological inhibition of LPA receptor 1 (LPAR1) abrogate cilia disassembly triggered by serum. The LPA-LPAR-G-protein pathway promotes the transcription and phosphorylation of cilia disassembly factors-Aurora A, through activating the transcription coactivators YAP/TAZ and calcium/CaM pathway, respectively. Deletion of Lpar1 in mice causes abnormally elongated cilia and decreased proliferation in neural progenitor cells, thereby resulting in defective neurogenesis. Collectively, our findings establish LPA as a physiological initiator of cilia disassembly and suggest targeting the metabolism of LPA and the LPA pathway as potential therapies for diseases with dysfunctional ciliogenesis.

scholarly journals Emerging Role of ODC1 in Neurodevelopmental Disorders and Brain Development

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 470
Author(s):  
Jeremy W. Prokop ◽  
Caleb P. Bupp ◽  
Austin Frisch ◽  
Stephanie M. Bilinovich ◽  
Daniel B. Campbell ◽  
...  
Keyword(s):  
Brain Development ◽  
Neural Progenitor Cells ◽  
Neurodevelopmental Disorder ◽  
Fetal Brain ◽  
Missense Variant ◽  
Neural Progenitor ◽  
Loss Of Function ◽  
Gain Of Function ◽  
Systematic Analysis ◽  
Function Expression

Ornithine decarboxylase 1 (ODC1 gene) has been linked through gain-of-function variants to a rare disease featuring developmental delay, alopecia, macrocephaly, and structural brain anomalies. ODC1 has been linked to additional diseases like cancer, with growing evidence for neurological contributions to schizophrenia, mood disorders, anxiety, epilepsy, learning, and suicidal behavior. The evidence of ODC1 connection to neural disorders highlights the need for a systematic analysis of ODC1 genotype-to-phenotype associations. An analysis of variants from ClinVar, Geno2MP, TOPMed, gnomAD, and COSMIC revealed an intellectual disability and seizure connected loss-of-function variant, ODC G84R (rs138359527, NC_000002.12:g.10444500C > T). The missense variant is found in ~1% of South Asian individuals and results in 2.5-fold decrease in enzyme function. Expression quantitative trait loci (eQTLs) reveal multiple functionally annotated, non-coding variants regulating ODC1 that associate with psychiatric/neurological phenotypes. Further dissection of RNA-Seq during fetal brain development and within cerebral organoids showed an association of ODC1 expression with cell proliferation of neural progenitor cells, suggesting gain-of-function variants with neural over-proliferation and loss-of-function variants with neural depletion. The linkage from the expression data of ODC1 in early neural progenitor proliferation to phenotypes of neurodevelopmental delay and to the connection of polyamine metabolites in brain function establish ODC1 as a bona fide neurodevelopmental disorder gene.

scholarly journals Multiplex enCas12a screens detect functional buffering among paralogs otherwise masked in monogenic Cas9 knockout screens

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Merve Dede ◽  
Megan McLaughlin ◽  
Eiru Kim ◽  
Traver Hart
Keyword(s):  
Cell Lines ◽  
Protein Complexes ◽  
Gene Knockout ◽  
Essential Genes ◽  
Loss Of Function ◽  
Systematic Analysis ◽  
Synthetic Lethal ◽  
Synthetic Lethal Interactions ◽  
Crispr Screen ◽  
A Cell

Abstract Background Pooled library CRISPR/Cas9 knockout screening across hundreds of cell lines has identified genes whose disruption leads to fitness defects, a critical step in identifying candidate cancer targets. However, the number of essential genes detected from these monogenic knockout screens is low compared to the number of constitutively expressed genes in a cell. Results Through a systematic analysis of screen data in cancer cell lines generated by the Cancer Dependency Map, we observe that half of all constitutively expressed genes are never detected in any CRISPR screen and that these never-essentials are highly enriched for paralogs. We investigated functional buffering among approximately 400 candidate paralog pairs using CRISPR/enCas12a dual-gene knockout screening in three cell lines. We observe 24 synthetic lethal paralog pairs that have escaped detection by monogenic knockout screens at stringent thresholds. Nineteen of 24 (79%) synthetic lethal interactions are present in at least two out of three cell lines and 14 of 24 (58%) are present in all three cell lines tested, including alternate subunits of stable protein complexes as well as functionally redundant enzymes. Conclusions Together, these observations strongly suggest that functionally redundant paralogs represent a targetable set of genetic dependencies that are systematically under-represented among cell-essential genes in monogenic CRISPR-based loss of function screens.

scholarly journals SEPT7 Interacts with KIF20A and Regulates the Proliferative State of Neural Progenitor Cells During Cortical Development

2019 ◽  
Vol 30 (5) ◽  
pp. 3030-3043 ◽  
Author(s):  
Runxiang Qiu ◽  
Qiu Runxiang ◽  
Anqi Geng ◽  
Jiancheng Liu ◽  
C Wilson Xu ◽  
...  
Keyword(s):  
Cell Division ◽  
Progenitor Cells ◽  
Neuronal Differentiation ◽  
Cell Fate ◽  
Neural Progenitor Cells ◽  
Cortical Development ◽  
Neural Progenitor ◽  
Mammalian Brain ◽  
Additional Cell ◽  
A Cell

Abstract Balanced proliferation and differentiation of neural progenitor cells (NPCs) are critical for brain development, but how the process is regulated and what components of the cell division machinery is involved are not well understood. Here we report that SEPT7, a cell division regulator originally identified in Saccharomyces cerevisiae, interacts with KIF20A in the intercellular bridge of dividing NPCs and plays an essential role in maintaining the proliferative state of NPCs during cortical development. Knockdown of SEPT7 in NPCs results in displacement of KIF20A from the midbody and early neuronal differentiation. NPC-specific inducible knockout of Sept7 causes early cell cycle exit, precocious neuronal differentiation, and ventriculomegaly in the cortex, but surprisingly does not lead to noticeable cytokinesis defect. Our data uncover an interaction of SEPT7 and KIF20A during NPC divisions and demonstrate a crucial role of SEPT7 in cell fate determination. In addition, this study presents a functional approach for identifying additional cell fate regulators of the mammalian brain.

scholarly journals Mammalian Fat and Dachsous cadherins regulate apical membrane organization in the embryonic cerebral cortex

2009 ◽  
Vol 185 (6) ◽  
pp. 959-967 ◽  
Author(s):  
Takashi Ishiuchi ◽  
Kazuyo Misaki ◽  
Shigenobu Yonemura ◽  
Masatoshi Takeichi ◽  
Takuji Tanoue
Keyword(s):  
Cerebral Cortex ◽  
Plasma Membrane ◽  
Progenitor Cells ◽  
Neural Progenitor Cells ◽  
Apical Membrane ◽  
Neural Progenitor ◽  
Apical Plasma Membrane ◽  
Cell Contact ◽  
Membrane Organization ◽  
A Cell

Compartmentalization of the plasma membrane in a cell is fundamental for its proper functions. In this study, we present evidence that mammalian Fat4 and Dachsous1 cadherins regulate the apical plasma membrane organization in the embryonic cerebral cortex. In neural progenitor cells of the cortex, Fat4 and Dachsous1 were concentrated together in a cell–cell contact area positioned more apically than the adherens junction (AJ). These molecules interacted in a heterophilic fashion, affecting their respective protein levels. We further found that Fat4 associated and colocalized with the Pals1 complex. Ultrastructurally, the apical junctions of the progenitor cells comprised the AJ and a stretch of plasma membrane apposition extending apically from the AJ, which positionally corresponded to the Fat4–Dachsous1-positive zone. Depletion of Fat4 or Pals1 abolished this membrane apposition. These results highlight the importance of the Fat4–Dachsous1–Pals1 complex in organizing the apical membrane architecture of neural progenitor cells.

scholarly journals Multiplex enCas12a screens show functional buffering by paralogs is systematically absent from genome-wide CRISPR/Cas9 knockout screens

2020 ◽  
Author(s):  
Merve Dede ◽  
Megan McLaughlin ◽  
Eiru Kim ◽  
Traver Hart
Keyword(s):  
Cell Lines ◽  
Protein Complexes ◽  
Essential Genes ◽  
Systematic Analysis ◽  
Synthetic Lethal ◽  
Genome Wide ◽  
Synthetic Lethal Interactions ◽  
Crispr Screen ◽  
A Cell ◽  
Genetic Buffering

AbstractMajor efforts on pooled library CRISPR knockout screening across hundreds of cell lines have identified genes whose disruption leads to fitness defects, a critical step in identifying candidate cancer targets. However, the number of essential genes detected from these monogenic knockout screens are very low compared to the number of constitutively expressed genes in a cell, raising the question of why there are so few essential genes. Through a systematic analysis of screen data in cancer cell lines generated by the Cancer Dependency Map, we observed that half of all constitutively-expressed genes are never hits in any CRISPR screen, and that these never-essentials are highly enriched for paralogs. We investigated paralog buffering through systematic dual-gene CRISPR knockout screening by testing algorithmically defined ~400 candidate paralog pairs with the enCas12a multiplex knockout system in three cell lines. We observed 24 synthetic lethal paralog pairs which have escaped detection by monogenic knockout screens at stringent thresholds. Nineteen of 24 (79%) synthetic lethal interactions were present in at least two out of three cell lines and 14 of 24 (58%) were present in all three cell lines tested, including alternate subunits of stable protein complexes as well as functionally redundant enzymes. Together these observations strongly suggest that paralogs represent a targetable set of genetic dependencies that are systematically under-represented among cell-essential genes due to genetic buffering in monogenic CRISPR-based mammalian functional genomics approaches.

scholarly journals Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling

2013 ◽  
Vol 304 (11) ◽  
pp. G1013-G1024 ◽  
Author(s):  
Anatoliy I. Masyuk ◽  
Bing Q. Huang ◽  
Brynn N. Radtke ◽  
Gabriella B. Gajdos ◽  
Patrick L. Splinter ◽  
...  
Keyword(s):  
Bile Acid ◽  
Functional Response ◽  
Primary Cilia ◽  
Intracellular Camp ◽  
Ciliated Cells ◽  
Functional Responses ◽  
Polycystic Liver ◽  
A Cell ◽  
And Function ◽  
In Cells

TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling.

scholarly journals Cell and molecular biology of Notch

2007 ◽  
Vol 194 (3) ◽  
pp. 459-474 ◽  
Author(s):  
Ulla-Maj Fiúza ◽  
Alfonso Martinez Arias
Keyword(s):  
Cell Fate ◽  
Cell Communication ◽  
Notch Signalling ◽  
Multiple Roles ◽  
Communication Process ◽  
Regulatory Mechanisms ◽  
Cell Populations ◽  
Notch Signalling Pathway ◽  
A Cell ◽  
Stem Cell Populations

Notch signalling is a cell–cell communication process, which allows the establishment of patterns of gene expression and differentiation, regulates binary cell fate choice and the maintenance of stem cell populations. So far, the data published has elucidated the main players in the Notch signalling pathway. However, its regulatory mechanisms are exhibiting an increasing complexity which could account for the multitude of roles it has during development and in adult organisms. In this review, we will describe the multiple roles of Notch and how various factors can regulate Notch signalling.

scholarly journals A synthetic metabolic network for physicochemical homeostasis

2019 ◽  
Author(s):  
Tjeerd Pols ◽  
Hendrik R. Sikkema ◽  
Bauke F. Gaastra ◽  
Jacopo Frallicciardi ◽  
Wojciech M. Śmigiel ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Living Cells ◽  
Metabolic Energy ◽  
Regulatory Mechanisms ◽  
Atp Production ◽  
Physical Chemical ◽  
A Cell ◽  
Chemical Conditions ◽  
Molecular Components

AbstractOne of the grand challenges in chemistry is the construction of functional out-of-equilibrium networks, which are typical of living cells. Building such a system from molecular components requires control over the formation and degradation of the interacting chemicals and homeostasis of the internal physical-chemical conditions. The provision and consumption of ATP lies at the heart of this challenge. We report the in vitro construction in vesicles of a pathway for sustained ATP production that is maintained away from equilibrium by control of energy dissipation. We maintain a constant level of ATP with varying load on the system. The pathway enables us to control the transmembrane fluxes of osmolytes and to demonstrate basic physicochemical homeostasis. Our work demonstrates metabolic energy conservation and cell volume regulatory mechanisms in a cell-like system at a level of complexity minimally needed for life.

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