scholarly journals CAMSAP3 is required for mTORC1-dependent ependymal cell growth and lateral ventricle shaping in mouse brains

Development ◽  
2021 ◽  
Vol 148 (3) ◽  
pp. dev195073
Author(s):  
Toshiya Kimura ◽  
Hiroko Saito ◽  
Miwa Kawasaki ◽  
Masatoshi Takeichi
Keyword(s):  
Cell Growth ◽  
Ependymal Cell ◽  
Ependymal Cells ◽  
Cellular Processes ◽  
Lateral Ventricles ◽  
Apical Domain ◽  
Mtorc1 Signaling ◽  
Subventricular Zones ◽  
Mtorc1 Activation ◽  
Mutant Cells

ABSTRACTMicrotubules (MTs) regulate numerous cellular processes, but their roles in brain morphogenesis are not well known. Here, we show that CAMSAP3, a non-centrosomal microtubule regulator, is important for shaping the lateral ventricles. In differentiating ependymal cells, CAMSAP3 became concentrated at the apical domains, serving to generate MT networks at these sites. Camsap3-mutated mice showed abnormally narrow lateral ventricles, in which excessive stenosis or fusion was induced, leading to a decrease of neural stem cells at the ventricular and subventricular zones. This defect was ascribed at least in part to a failure of neocortical ependymal cells to broaden their apical domain, a process necessary for expanding the ventricular cavities. mTORC1 was required for ependymal cell growth but its activity was downregulated in mutant cells. Lysosomes, which mediate mTORC1 activation, tended to be reduced at the apical regions of the mutant cells, along with disorganized apical MT networks at the corresponding sites. These findings suggest that CAMSAP3 supports mTORC1 signaling required for ependymal cell growth via MT network regulation, and, in turn, shaping of the lateral ventricles.

CAMSAP3 is required for mTORC1-dependent ependymal cell growth and lateral ventricle shaping in mouse brains

2020 ◽  
Author(s):  
Toshiya Kimura ◽  
Hiroko Saito ◽  
Miwa Kawasaki ◽  
Masatoshi Takeichi
Keyword(s):  
Cell Growth ◽  
Ependymal Cell ◽  
Microtubule Assembly ◽  
Ependymal Cells ◽  
Cellular Processes ◽  
Lateral Ventricles ◽  
Mtorc1 Signaling ◽  
Subventricular Zones ◽  
Mtorc1 Activation ◽  
Mutant Cells

AbstractMicrotubules (MTs) regulate numerous cellular processes, but their roles in brain morphogenesis are not well known. Here we show that CAMSAP3, a non-centrosomal microtubule regulator, is important for shaping the lateral ventricles. In differentiating ependymal cells, CAMSAP3 became concentrated at the apical domains, serving to generate MT networks at these sites. Camsap3-mutated mice showed abnormally narrow lateral ventricles, in which excessive stenosis or fusion was induced, leading to a decrease of neural stem cells at the ventricular and subventricular zones. This defect was ascribed at least in part to a failure of neocortical ependymal cells to broaden their apical domain, a process necessary for expanding the ventricular cavities. mTORC1 was required for ependymal cell growth but its activity was downregulated in mutant cells. Lysosomes, which mediate mTORC1 activation, tended to be reduced at the apical regions of the mutant cells, along with disorganized apical MT networks at the corresponding sites. These findings suggest that CAMSAP3 supports mTORC1 signaling required for ependymal cell growth via MT network regulation, and, in turn, shaping of the lateral ventricles.Summary statementCAMSAP3, which mediates non-centrosomal microtubule assembly, is required for mTORC1-dependent maturation of ependymal cells at the neocortex of developing mouse brains. Loss of CAMSAP3 causes deformation of the lateral ventricles.

scholarly journals Peak ependymal cell stretch overlaps with the onset location of periventricular white matter lesions

2021 ◽  
Author(s):  
Valery Visser ◽  
Henry Rusinek ◽  
Johannes Weickenmeier
Keyword(s):  
White Matter ◽  
Ependymal Cell ◽  
White Matter Lesions ◽  
Magnetic Resonance Images ◽  
Ependymal Cells ◽  
Periventricular White Matter ◽  
Ventricular Wall ◽  
Imaging Data ◽  
Lateral Ventricles ◽  
Cell Stretch

Abstract Deep and periventricular white matter hyperintensities (dWMH/pvWMH) are bright appearing white matter tissue lesions in T2-weighted fluid attenuated inversion recovery magnetic resonance images and are frequent observations in the aging human brain. While early stages of these white matter lesions are only weakly associated with cognitive impairment, their progressive growth is a strong indicator for long-term functional decline. DWMHs are typically associated with vascular degeneration in diffuse white matter locations; for pvWMHs, however, no unifying theory exists to explain their consistent onset around the horns of the lateral ventricles. We use patient imaging data to create anatomically accurate finite element models of the lateral ventricles, white and gray matter, and cerebrospinal fluid, as well as to reconstruct their WMH volumes. We simulated the mechanical loading of the ependymal cells forming the primary brain-fluid interface, the ventricular wall, and its surrounding tissues at peak ventricular pressure during the hemodynamic cycle. We observe that both the maximum principal tissue strain and the largest ependymal cell stretch consistently localize in the anterior and posterior horns. Our simulations show that ependymal cells experience a loading state that causes the ventricular wall to be stretched thin. Moreover, we show that maximum wall loading coincides with the pvWMH locations observed in our patient scans. These results warrant further analysis of white matter pathology in the periventricular zone that includes a mechanics-driven deterioration model for the ventricular wall.

scholarly journals Deletion of murine IQGAP1 results in increased mTOR activation and blunted ketogenic response

2017 ◽  
Author(s):  
Hanna Erickson ◽  
Sayeepriyadarshini Anakk
Keyword(s):  
Ectopic Expression ◽  
Scaffolding Protein ◽  
Iq Motif ◽  
Cellular Processes ◽  
Metabolic Genes ◽  
Mtorc1 Signaling ◽  
Important Regulator ◽  
Mtorc1 Activation ◽  
Mtor Complex 1

AbstractIQ motif-containing GTPase Activating Protein 1 (IQGAP1) is a ubiquitously expressed scaffolding protein that integrates signaling from multiple cellular processes including motility, adhesion, and proliferation. Here, we show that IQGAP1 is induced in the liver upon fasting and can also regulate β-oxidation and ketone body synthesis. Utilizing ketogenic diet and pharmacologic activation we identified that hepatic PPARα activity is compromised in Iqgap1-/-mice. Our data show that IQGAP1 interacts with the mechanistic target of rapamycin (mTOR) and IQGAP1 deletion results in enhanced mTOR complex 1 (mTORC1) activation. Conversely, ectopic expression of IQGAP1 in Iqgap1-/- mice was sufficient to suppress mTORC1 signaling. We also confirmed that modulation of mTORC1 signaling by IQGAP1 is cell autonomous. This increased mTORC1 activation impedes PPARα signaling since mTORC1 inhibition restored a subset of metabolic genes in Iqgap1-/- mice. Overall, we demonstrate a previously unidentified role for IQGAP1 as an important regulator of mTORC1 activity and long-term ketosis.

Scanning Electron Microscopy of the Choroid Plexus and Ventricular Wall Ependyma in the Rhesus Monkey

1971 ◽  
Vol 29 ◽  
pp. 270-271
Author(s):  
Philip P. McGrath ◽  
Ronald G. Clark ◽  
John B. Ewell ◽  
John M. Wehrung
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Choroid Plexus ◽  
Ependymal Cell ◽  
Brain Parenchyma ◽  
Ependymal Cells ◽  
Apical Surface ◽  
Lateral Ventricles ◽  
Scanning Electron

The lumen of the lateral ventricles is separated from the brain parenchyma and the circulatory system by a single layer of specialized epithelial cells, the ependyma. This ependyma is divided into choroid plexus ependymal cells, which coat the pia arachnoid invagination in the lateral ventricles, and the wall ependymal cells which separate the lateral ventricle lumen from brain parenchyma. Using transmission electron microscopy, the ultrastructure of these cells has been described with special emphasis on the difference in apical surface membranes. The apical surface of the choroid plexus ependymal cell contains numerous microvilli and an occasional cilia while the wall ependymal cell contains numerous cilia and only a few microvilli. By scanning electron microscope we have demonstrated differences in the apical surface membrane.The specimens were fixed in glutaraldehyde by vascular perfusion or infusion into the ventricles and postfixed in osmium tetroxide. They were rinsed in cacodylate buffer and three changes of distilled water, blotted dry, and freeze dried, using liquid nitrogen. They were coated with gold palladium and examined in a Cambridge Mark II A stereoscan, scanning electron microscope.

scholarly journals Peak ependymal cell stretch overlaps with the onset locations of periventricular white matter lesions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Valery L. Visser ◽  
Henry Rusinek ◽  
Johannes Weickenmeier
Keyword(s):  
White Matter ◽  
Ependymal Cell ◽  
White Matter Lesions ◽  
Magnetic Resonance Images ◽  
Ependymal Cells ◽  
Periventricular White Matter ◽  
Ventricular Wall ◽  
Imaging Data ◽  
Lateral Ventricles ◽  
Cell Stretch

AbstractDeep and periventricular white matter hyperintensities (dWMH/pvWMH) are bright appearing white matter tissue lesions in T2-weighted fluid attenuated inversion recovery magnetic resonance images and are frequent observations in the aging human brain. While early stages of these white matter lesions are only weakly associated with cognitive impairment, their progressive growth is a strong indicator for long-term functional decline. DWMHs are typically associated with vascular degeneration in diffuse white matter locations; for pvWMHs, however, no unifying theory exists to explain their consistent onset around the horns of the lateral ventricles. We use patient imaging data to create anatomically accurate finite element models of the lateral ventricles, white and gray matter, and cerebrospinal fluid, as well as to reconstruct their WMH volumes. We simulated the mechanical loading of the ependymal cells forming the primary brain-fluid interface, the ventricular wall, and its surrounding tissues at peak ventricular pressure during the hemodynamic cycle. We observe that both the maximum principal tissue strain and the largest ependymal cell stretch consistently localize in the anterior and posterior horns. Our simulations show that ependymal cells experience a loading state that causes the ventricular wall to be stretched thin. Moreover, we show that maximum wall loading coincides with the pvWMH locations observed in our patient scans. These results warrant further analysis of white matter pathology in the periventricular zone that includes a mechanics-driven deterioration model for the ventricular wall.

scholarly journals Tracking changes in adaptation to suspension growth for MDCK cells: cell growth correlates with levels of metabolites, enzymes and proteins

2021 ◽  
Vol 105 (5) ◽  
pp. 1861-1874
Author(s):  
Sabine Pech ◽  
Markus Rehberg ◽  
Robert Janke ◽  
Dirk Benndorf ◽  
Yvonne Genzel ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cell Line ◽  
Mdck Cells ◽  
Suspension Cell ◽  
Regulatory Mechanisms ◽  
Adherent Cell ◽  
Holistic View ◽  
Cellular Processes ◽  
Viral Vaccine ◽  
Analytical Approaches

Abstract Adaptations of animal cells to growth in suspension culture concern in particular viral vaccine production, where very specific aspects of virus-host cell interaction need to be taken into account to achieve high cell specific yields and overall process productivity. So far, the complexity of alterations on the metabolism, enzyme, and proteome level required for adaptation is only poorly understood. In this study, for the first time, we combined several complex analytical approaches with the aim to track cellular changes on different levels and to unravel interconnections and correlations. Therefore, a Madin-Darby canine kidney (MDCK) suspension cell line, adapted earlier to growth in suspension, was cultivated in a 1-L bioreactor. Cell concentrations and cell volumes, extracellular metabolite concentrations, and intracellular enzyme activities were determined. The experimental data set was used as the input for a segregated growth model that was already applied to describe the growth dynamics of the parental adherent cell line. In addition, the cellular proteome was analyzed by liquid chromatography coupled to tandem mass spectrometry using a label-free protein quantification method to unravel altered cellular processes for the suspension and the adherent cell line. Four regulatory mechanisms were identified as a response of the adaptation of adherent MDCK cells to growth in suspension. These regulatory mechanisms were linked to the proteins caveolin, cadherin-1, and pirin. Combining cell, metabolite, enzyme, and protein measurements with mathematical modeling generated a more holistic view on cellular processes involved in the adaptation of an adherent cell line to suspension growth. Key points • Less and more efficient glucose utilization for suspension cell growth • Concerted alteration of metabolic enzyme activity and protein expression • Protein candidates to interfere glycolytic activity in MDCK cells

scholarly journals The Putative Eukaryote-LikeO-GlcNAc Transferase of the Cyanobacterium Synechococcus elongatus PCC 7942 Hydrolyzes UDP-GlcNAc and Is Involved in Multiple Cellular Processes

2014 ◽  
Vol 197 (2) ◽  
pp. 354-361 ◽  
Author(s):  
Kerry A. Sokol ◽  
Neil E. Olszewski
Keyword(s):  
Deletion Mutant ◽  
Bacterial Species ◽  
Synechococcus Elongatus ◽  
Single Amino Acid ◽  
Content Type ◽  
Cellular Processes ◽  
Mutant Phenotypes ◽  
Glcnac Transferase ◽  
Pcc 7942 ◽  
Mutant Cells

The posttranslational addition of a single O-linked β-N-acetylglucosamine (O-GlcNAc) to serine or threonine residues regulates numerous metazoan cellular processes. The enzyme responsible for this modification,O-GlcNAc transferase (OGT), is conserved among a wide variety of organisms and is critical for the viability of many eukaryotes. Although OGTs with domain structures similar to those of eukaryotic OGTs are predicted for many bacterial species, the cellular roles of these OGTs are unknown. We have identified a putative OGT in the cyanobacteriumSynechococcus elongatusPCC 7942 that shows active-site homology and similar domain structure to eukaryotic OGTs. An OGT deletion mutant was created and found to exhibit several phenotypes. Without agitation, mutant cells aggregate and settle out of the medium. The mutant cells have higher free inorganic phosphate levels, wider thylakoid lumen, and differential accumulation of electron-dense inclusion bodies. These phenotypes are rescued by reintroduction of the wild-type OGT but are not fully rescued by OGTs with single amino acid substitutions corresponding to mutations that reduce eukaryotic OGT activity.S. elongatusOGT purified fromEscherichia colihydrolyzed the sugar donor, UDP-GlcNAc, while the mutant OGTs that did not fully rescue the deletion mutant phenotypes had reduced or no activity. These results suggest that bacterial eukaryote-like OGTs, like their eukaryotic counterparts, influence multiple processes.

scholarly journals Prostaglandin E2 activates the mTORC1 pathway through an EP4/cAMP/PKA- and EP1/Ca2+-mediated mechanism in the human pancreatic carcinoma cell line PANC-1

2015 ◽  
Vol 309 (10) ◽  
pp. C639-C649 ◽  
Author(s):  
Hui-Hua Chang ◽  
Steven H. Young ◽  
James Sinnett-Smith ◽  
Caroline Ei Ne Chou ◽  
Aune Moro ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Pancreatic Cancer ◽  
Prostaglandin E2 ◽  
Human Pancreatic Cancer ◽  
Pancreatic Carcinoma Cell Line ◽  
Pancreatic Cancer Cells ◽  
Mtorc1 Signaling ◽  
Mtorc1 Pathway ◽  
Pka Pathway ◽  
Mtorc1 Activation

Obesity, a known risk factor for pancreatic cancer, is associated with inflammation and insulin resistance. Proinflammatory prostaglandin E2 (PGE2) and elevated insulin-like growth factor type 1 (IGF-1), related to insulin resistance, are shown to play critical roles in pancreatic cancer progression. We aimed to explore a potential cross talk between PGE2 signaling and the IGF-1/Akt/mammalian target of rapamycin complex 1 (mTORC1) pathway in pancreatic cancer, which may be a key to unraveling the obesity-cancer link. In PANC-1 human pancreatic cancer cells, we showed that PGE2 stimulated mTORC1 activity independently of Akt, as evaluated by downstream signaling events. Subsequently, using pharmacological and genetic approaches, we demonstrated that PGE2-induced mTORC1 activation is mediated by the EP4/cAMP/PKA pathway, as well as an EP1/Ca2+-dependent pathway. The cooperative roles of the two pathways were supported by the maximal inhibition achieved with the combined pharmacological blockade, and the coexistence of highly expressed EP1 (mediating the Ca2+ response) and EP2 or EP4 (mediating the cAMP/PKA pathway) in PANC-1 cells and in the prostate cancer line PC-3, which also robustly exhibited PGE2-induced mTORC1 activation, as identified from a screen in various cancer cell lines. Importantly, we showed a reinforcing interaction between PGE2 and IGF-1 on mTORC1 signaling, with an increase in IL-23 production as a cellular outcome. Our data reveal a previously unrecognized mechanism of PGE2-stimulated mTORC1 activation mediated by EP4/cAMP/PKA and EP1/Ca2+ signaling, which may be of great importance in elucidating the promoting effects of obesity in pancreatic cancer. Ultimately, a precise understanding of these molecular links may provide novel targets for efficacious interventions devoid of adverse effects.

Tight junctions

1998 ◽  
Vol 111 (5) ◽  
pp. 541-547 ◽  
Author(s):  
M.S. Balda ◽  
K. Matter
Keyword(s):  
Endothelial Cells ◽  
Cell Growth ◽  
Tight Junctions ◽  
Diffusion Barrier ◽  
Basolateral Membrane ◽  
Intercellular Junctions ◽  
Cellular Level ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Membrane Components

Tight junctions are the most apical intercellular junctions of epithelial and endothelial cells and create a regulatable semipermeable diffusion barrier between individual cells. On a cellular level, they form an intramembrane diffusion fence that restricts the intermixing of apical and basolateral membrane components. In addition to these well defined functions, more recent evidence suggests that tight junctions are also involved in basic cellular processes like the regulation of cell growth and differentiation.

scholarly journals Mitochondrial Histone-Like DNA-Binding Proteins Are Essential for Normal Cell Growth and Mitochondrial Function in Crithidia fasciculata

2004 ◽  
Vol 3 (2) ◽  
pp. 518-526 ◽  
Author(s):  
Nuraly K. Avliyakulov ◽  
Julius Lukeš ◽  
Dan S. Ray
Keyword(s):  
Cell Growth ◽  
Dna Binding ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Mrna Levels ◽  
Chromosomal Dna ◽  
Double Knockout ◽  
Crithidia Fasciculata ◽  
Sequence Encoding ◽  
Mutant Cells

ABSTRACT The Crithidia fasciculata KAP2 and KAP3 proteins are closely related kinetoplast-specific histone-like DNA-binding proteins. The KAP2 and KAP3 genes are 46% identical and are arranged in tandem on the chromosomal DNA. Disruption of both alleles of either gene alone shows no detectable phenotype. However, replacement of both copies of the sequence encoding the entire KAP2 and KAP3 locus increases maxicircle mRNA levels two- to fourfold. These double-knockout cells are viable but grow extremely slowly, have reduced respiration and very abnormal cell morphologies, and accumulate numerous large vacuoles. The extreme phenotype of these mutant cells suggests an important role for the KAP2 and KAP3 proteins in mitochondrial metabolism and cell growth.

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