scholarly journals Tubulin glycylases and glutamylases have distinct functions in stabilization and motility of ependymal cilia

2013 ◽  
Vol 202 (3) ◽  
pp. 441-451 ◽  
Author(s):  
Montserrat Bosch Grau ◽  
Gloria Gonzalez Curto ◽  
Cecilia Rocha ◽  
Maria M. Magiera ◽  
Patricia Marques Sousa ◽  
...  
Keyword(s):  
Brain Development ◽  
Posttranslational Modifications ◽  
Mammalian Brain ◽  
Potential Importance ◽  
Ependymal Cilia ◽  
Motile Cilia ◽  
Cilia And Flagella ◽  
The Brain

Microtubules are subject to a variety of posttranslational modifications that potentially regulate cytoskeletal functions. Two modifications, glutamylation and glycylation, are highly enriched in the axonemes of most eukaryotes, and might therefore play particularly important roles in cilia and flagella. Here we systematically analyze the dynamics of glutamylation and glycylation in developing mouse ependymal cilia and the expression of the corresponding enzymes in the brain. By systematically screening enzymes of the TTLL family for specific functions in ependymal cilia, we demonstrate that the glycylating enzymes TTLL3 and TTLL8 were required for stability and maintenance of ependymal cilia, whereas the polyglutamylase TTLL6 was necessary for coordinated beating behavior. Our work provides evidence for a functional separation of glutamylating and glycylating enzymes in mammalian ependymal cilia. It further advances the elucidation of the functions of tubulin posttranslational modifications in motile cilia of the mammalian brain and their potential importance in brain development and disease.

scholarly journals Computational Modeling of Motile Cilia Generated Cerebral Flow Dynamics in Zebrafish Embryo

2020 ◽  
Author(s):  
Huseyin Enes Salman ◽  
Natalie Jurisch Yaksi ◽  
Huseyin Cagatay Yalcin
Keyword(s):  
Brain Development ◽  
Flow Velocity ◽  
Zebrafish Embryo ◽  
Flow Dynamics ◽  
Csf Flow ◽  
Brain Ventricles ◽  
Ciliary Beating ◽  
Directional Flow ◽  
Motile Cilia ◽  
The Brain

Background: Motile cilia are hair-like microscopic structures, which move the fluids along the epithelial surfaces. Cilia cover a wide range of regions in the nervous system, such as the nasal cavity, spinal cord central canal, and brain ventricles. Motile cilia-driven cerebrospinal fluid (CSF) flow in the brain ventricles has an important role in the brain development. Embryos lacking motile cilia develop neurological defects due to altered CSF flow. Aim: To investigate the effect of motile-cilia motion on the altered CSF flow, and to understand the role of CSF flow in the brain development and physiology. Methods: The dynamics of motile-cilia driven flow is analyzed employing computational fluid dynamics (CFD) modeling. A 2D model is generated using the time-lapse microscopic movies showing movements of a fluorescently labeled motile-cilia in a zebrafish embryo (48-hour post-fertilization). The effects on the generated flow are elucidated by investigating the cilia beating angle, multiple cilia formations, and the phase difference between different ciliary beats. Results: Ciliary beating generated a directional flow in the form of a circulating vortex. The angle of ciliary beating significantly affected the flow velocity. As the angle between the wall and cilia decreases, the flow becomes more efficient by achieving higher velocities. Multiple cilia formations increased the flow velocity but the significance of multiple cilia is not as critical as the beating angle. Interestingly, phase difference between the multiple cilia beats increased the directional flow velocity. Conclusion: Motile-cilia generated flow dynamics are investigated, and it is concluded that out-of-phase multiple ciliary beating is the optimum form of beating in order to generate a directional flow.

scholarly journals Synchronization of mammalian motile cilia in the brain with hydrodynamic forces

2019 ◽  
Author(s):  
Nicola Pellicciotta ◽  
Evelyn Hamilton ◽  
Jurij Kotar ◽  
Marion Faucourt ◽  
Nathalie Degehyr ◽  
...  
Keyword(s):  
Mechanistic Model ◽  
Hydrodynamic Forces ◽  
Coordination Mechanism ◽  
Mammalian Brain ◽  
Similar Frequency ◽  
Multiciliated Cells ◽  
Motile Cilia ◽  
External Flows ◽  
The Brain

Motile cilia are widespread across the animal and plant kingdoms, displaying complex collective dynamics central to their physiology. Their coordination mechanism is not generally understood, with pre-vious work mainly focusing on algae and protists. We study here the synchronization of cilia beat in multiciliated cells from brain ven-tricles. The response to controlled oscillatory external flows shows that strong flows at a similar frequency to the actively beating cilia can entrain cilia oscillations. We find that the hydrodynamic forces required for this entrainment strongly depend on the number of cilia per cell. Cells with few cilia (up to five) can be entrained at flows comparable to the cilia-driven flows reported in vivo. Simulations of a minimal model of cilia interacting hydrodynamically show the same trends observed in cilia. Our results suggest that hydrody-namic forces between cilia are sufficient to be the mechanism behind the synchronization of mammalian brain cilia dynamics.Significance StatementIt is shown experimentally, and also reproducing key qualitative results in a minimal mechanistic model simulated numerically, that in the motile cilia of the brain hydrodynamic forces of the magnitude that cilia themselves can generate are sufficient to establish the coordination of dynamics which is so crucial phys-iologically. This is the first experiment of its kind on multicilated cells, the key result is the unexpected importance of cilia num-ber per cell, with cells with fewer cilia much more susceptible to external flows. This finding changes the way in which we think about the question of collective cilia beating - it is not correct to simply examine isolated cilia and draw conclusions about the behaviour of cilia assemblies in multiciliated cells.

scholarly journals A novel hypomorphic allele of Spag17 causes primary ciliary dyskinesia phenotypes in mice

2020 ◽  
Author(s):  
Zakia Abdelhamed ◽  
Marshall Lukacs ◽  
Sandra Cindric ◽  
Heymut Omran ◽  
Rolf W. Stottmann
Keyword(s):  
Primary Ciliary Dyskinesia ◽  
Molecular Mechanisms ◽  
Premature Stop Codon ◽  
Human Condition ◽  
Csf Flow ◽  
Hypomorphic Allele ◽  
Ependymal Cilia ◽  
Motile Cilia ◽  
The Brain ◽  
Ciliary Dyskinesia

AbstractPrimary ciliary dyskinesia (PCD) is a human condition of dysfunctional motile cilia characterized by recurrent lung infection, infertility, organ laterality defects, and partially penetrant hydrocephalus. We recovered a mouse mutant from a forward genetic screen that developed all the phenotypes of PCD. Whole exome sequencing identified this primary ciliary dyskinesia only (Pcdo) allele to be a nonsense mutation (c.5236A>T) in the Spag17 coding sequence creating a premature stop codon at position 1746 (K1746*). The Pcdo variant abolished different isoforms of SPAG17 in the Pcdo mutant testis but not in the brain. Our data indicate differential requirements for SPAG17 in different motile cilia cell types. SPAG17 is required for proper development of the sperm flagellum, and is essential for either development or stability of the C1 microtubule structure within cilia, but not the brain ependymal cilia. We identified changes in ependymal cilia beating frequency but these did not apparently alter lateral ventricle cerebrospinal fluid (CSF) flow. Aqueductal (Aq) stenosis resulted in significantly slower and abnormally directed CSF flow and we suggest this is the root cause of the hydrocephalus. The Spag17Pcdo homozygous mutant mice are generally viable to adulthood, but have a significantly shortened life span with chronic morbidity. Our data indicate that the c.5236A>T Pcdo variant is a hypomorphic allele of Spag17 gene that causes phenotypes related to motile, but not primary, cilia. Spag17Pcdo is a novel and useful model for elucidating the molecular mechanisms underlying development of PCD in the mouse.

scholarly journals Tubulin glycylation controls primary cilia length

2017 ◽  
Vol 216 (9) ◽  
pp. 2701-2713 ◽  
Author(s):  
Sudarshan Gadadhar ◽  
Hala Dadi ◽  
Satish Bodakuntla ◽  
Anne Schnitzler ◽  
Ivan Bièche ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Primary Cilia ◽  
Cultured Cells ◽  
Dependent Manner ◽  
Specific Antibodies ◽  
Essential Components ◽  
Human Disorders ◽  
Motile Cilia ◽  
Cilia And Flagella

As essential components of the eukaryotic cytoskeleton, microtubules fulfill a variety of functions that can be temporally and spatially controlled by tubulin posttranslational modifications. Tubulin glycylation has so far been mostly found on motile cilia and flagella, where it is involved in the stabilization of the axoneme. In contrast, barely anything is known about the role of glycylation in primary cilia because of limitations in detecting this modification in these organelles. We thus developed novel glycylation-specific antibodies with which we detected glycylation in many primary cilia. Glycylation accumulates in primary cilia in a length-dependent manner, and depletion or overexpression of glycylating enzymes modulates the length of primary cilia in cultured cells. This strongly suggests that glycylation is essential for the homeostasis of primary cilia, which has important implications for human disorders related to primary cilia dysfunctions, such as ciliopathies and certain types of cancer.

scholarly journals The regulatory roles of motile cilia in CSF circulation and hydrocephalus

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Vijay Kumar ◽  
Zobia Umair ◽  
Shiv Kumar ◽  
Ravi Shankar Goutam ◽  
Soochul Park ◽  
...  
Keyword(s):  
Brain Development ◽  
Main Body ◽  
Csf Circulation ◽  
Multiciliated Cells ◽  
Abnormal Accumulation ◽  
Motile Cilia ◽  
The Brain ◽  
Severe Hydrocephalus ◽  
Ependymal Lining

Abstract Background Cerebrospinal fluid (CSF) is an ultra-filtrated colorless brain fluid that circulates within brain spaces like the ventricular cavities, subarachnoid space, and the spine. Its continuous flow serves many primary functions, including nourishment, brain protection, and waste removal. Main body The abnormal accumulation of CSF in brain cavities triggers severe hydrocephalus. Accumulating evidence had indicated that synchronized beats of motile cilia (cilia from multiciliated cells or the ependymal lining in brain ventricles) provide forceful pressure to generate and restrain CSF flow and maintain overall CSF circulation within brain spaces. In humans, the disorders caused by defective primary and/or motile cilia are generally referred to as ciliopathies. The key role of CSF circulation in brain development and its functioning has not been fully elucidated. Conclusions In this review, we briefly discuss the underlying role of motile cilia in CSF circulation and hydrocephalus. We have reviewed cilia and ciliated cells in the brain and the existing evidence for the regulatory role of functional cilia in CSF circulation in the brain. We further discuss the findings obtained for defective cilia and their potential involvement in hydrocephalus. Furthermore, this review will reinforce the idea of motile cilia as master regulators of CSF movements, brain development, and neuronal diseases.

scholarly journals An architectonic type principle in the development of laminar patterns of cortico-cortical connections

2021 ◽  
Author(s):  
Sarah F. Beul ◽  
Alexandros Goulas ◽  
Claus C. Hilgetag
Keyword(s):  
Structural Connectivity ◽  
Macaque Monkey ◽  
Brain Regions ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Cortical Connections ◽  
Cortical Projections ◽  
Structural Connections ◽  
High Degree ◽  
The Brain

AbstractStructural connections between cortical areas form an intricate network with a high degree of specificity. Many aspects of this complex network organization in the adult mammalian cortex are captured by an architectonic type principle, which relates structural connections to the architectonic differentiation of brain regions. In particular, the laminar patterns of projection origins are a prominent feature of structural connections that varies in a graded manner with the relative architectonic differentiation of connected areas in the adult brain. Here we show that the architectonic type principle is already apparent for the laminar origins of cortico-cortical projections in the immature cortex of the macaque monkey. We find that prenatal and neonatal laminar patterns correlate with cortical architectonic differentiation, and that the relation of laminar patterns to architectonic differences between connected areas is not substantially altered by the complete loss of visual input. Moreover, we find that the degree of change in laminar patterns that projections undergo during development varies in proportion to the relative architectonic differentiation of the connected areas. Hence, it appears that initial biases in laminar projection patterns become progressively strengthened by later developmental processes. These findings suggest that early neurogenetic processes during the formation of the brain are sufficient to establish the characteristic laminar projection patterns. This conclusion is in line with previously suggested mechanistic explanations underlying the emergence of the architectonic type principle and provides further constraints for exploring the fundamental factors that shape structural connectivity in the mammalian brain.

scholarly journals Tubulin glycylation controls axonemal dynein activity, flagellar beat, and male fertility

Science ◽  
2021 ◽  
Vol 371 (6525) ◽  
pp. eabd4914
Author(s):  
Sudarshan Gadadhar ◽  
Gonzalo Alvarez Viar ◽  
Jan Niklas Hansen ◽  
An Gong ◽  
Aleksandr Kostarev ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Male Fertility ◽  
Electron Tomography ◽  
Structural Basis ◽  
Cellular Functions ◽  
Flagellar Beat ◽  
Cryo Electron Tomography ◽  
Axonemal Dynein ◽  
Dynein Arms ◽  
Cilia And Flagella

Posttranslational modifications of the microtubule cytoskeleton have emerged as key regulators of cellular functions, and their perturbations have been linked to a growing number of human pathologies. Tubulin glycylation modifies microtubules specifically in cilia and flagella, but its functional and mechanistic roles remain unclear. In this study, we generated a mouse model entirely lacking tubulin glycylation. Male mice were subfertile owing to aberrant beat patterns of their sperm flagella, which impeded the straight swimming of sperm cells. Using cryo–electron tomography, we showed that lack of glycylation caused abnormal conformations of the dynein arms within sperm axonemes, providing the structural basis for the observed dysfunction. Our findings reveal the importance of microtubule glycylation for controlled flagellar beating, directional sperm swimming, and male fertility.

scholarly journals Modeling temperature- and Cav3 subtype-dependent alterations in T-type calcium channel mediated burst firing

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fernando R. Fernandez ◽  
Mircea C. Iftinca ◽  
Gerald W. Zamponi ◽  
Ray W. Turner
Keyword(s):  
Calcium Channel ◽  
Neuronal Excitability ◽  
Neuronal Firing ◽  
Mammalian Brain ◽  
Peripheral Tissues ◽  
Window Current ◽  
Modeling Data ◽  
The Brain ◽  
Firing Neuron ◽  
Cav3 Channel

AbstractT-type calcium channels are important regulators of neuronal excitability. The mammalian brain expresses three T-type channel isoforms (Cav3.1, Cav3.2 and Cav3.3) with distinct biophysical properties that are critically regulated by temperature. Here, we test the effects of how temperature affects spike output in a reduced firing neuron model expressing specific Cav3 channel isoforms. The modeling data revealed only a minimal effect on baseline spontaneous firing near rest, but a dramatic increase in rebound burst discharge frequency for Cav3.1 compared to Cav3.2 or Cav3.3 due to differences in window current or activation/recovery time constants. The reduced response by Cav3.2 could optimize its activity where it is expressed in peripheral tissues more subject to temperature variations than Cav3.1 or Cav3.3 channels expressed prominently in the brain. These tests thus reveal that aspects of neuronal firing behavior are critically dependent on both temperature and T-type calcium channel subtype.

scholarly journals Involvement of Thyroid Hormones in Brain Development and Cancer

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2693
Author(s):  
Gabriella Schiera ◽  
Carlo Maria Di Liegro ◽  
Italia Di Liegro
Keyword(s):  
Nervous System ◽  
Thyroid Hormones ◽  
Brain Development ◽  
Placental Transfer ◽  
Regulation Of Gene Expression ◽  
Mammalian Brain ◽  
Cancer Proliferation ◽  
Fetal Thyroid ◽  
Genomic Effects ◽  
And Function

The development and maturation of the mammalian brain are regulated by thyroid hormones (THs). Both hypothyroidism and hyperthyroidism cause serious anomalies in the organization and function of the nervous system. Most importantly, brain development is sensitive to TH supply well before the onset of the fetal thyroid function, and thus depends on the trans-placental transfer of maternal THs during pregnancy. Although the mechanism of action of THs mainly involves direct regulation of gene expression (genomic effects), mediated by nuclear receptors (THRs), it is now clear that THs can elicit cell responses also by binding to plasma membrane sites (non-genomic effects). Genomic and non-genomic effects of THs cooperate in modeling chromatin organization and function, thus controlling proliferation, maturation, and metabolism of the nervous system. However, the complex interplay of THs with their targets has also been suggested to impact cancer proliferation as well as metastatic processes. Herein, after discussing the general mechanisms of action of THs and their physiological effects on the nervous system, we will summarize a collection of data showing that thyroid hormone levels might influence cancer proliferation and invasion.

XVI. Note on the minute structure of the grey matter of the convolutions of the brain of man, the sheep, cat, and dog

1863 ◽  
Vol 12 ◽  
pp. 671-673
Keyword(s):  
Grey Matter ◽  
Nerve Cells ◽  
Mammalian Brain ◽  
New Process ◽  
The Brain ◽  
Thick Fibre

By a new process of investigation, I have succeeded in demonstrating the connexion between the nerve-cells and fibres in the grey matter of the convolutions and in other parts of the mammalian brain, and have followed individual fibres for a much greater distance than can be effected in sections prepared by other processes of investigation which I have tried. In many instances one thick fibre is continuous with one or other extremity of the “cell,” while from its opposite portion from three to six or eight thinner fibres diverge in a direction onwards and outwards. This arrangement is particularly distinct in the grey matter of the sheep’s brain.

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