scholarly journals Mapping calcium dynamics in a developing tubular structure

2020 ◽  
Author(s):  
Jorgen Hoyer ◽  
Morsal Saba ◽  
Daniel Dondorp ◽  
Kushal Kolar ◽  
Riccardo Esposito ◽  
...  
Keyword(s):  
Cell Types ◽  
Feedback Mechanism ◽  
Adult Brain ◽  
Actin Dynamics ◽  
Cytoskeletal Network ◽  
Notochord Cell ◽  
Wide Range ◽  
Store Operated Calcium Entry ◽  
And Function ◽  
Cell Intercalation

AbstractCalcium is a ubiquitous and versatile second messenger that plays a central role in the development and function of a wide range of cell types, tissues and organs. Despite significant recent progress in the understanding of calcium (Ca2+) signalling in organs such as the developing and adult brain, we have relatively little knowledge of the contribution of Ca2+ to the development of tubes, structures widely present in multicellular organisms. Here we image Ca2+ dynamics in the developing notochord of Ciona intestinalis. We show that notochord cells exhibit distinct Ca2+ dynamics during specific morphogenetic events such as cell intercalation, cell elongation and tubulogenesis. We used an optogenetically controlled Ca2+ actuator to show that sequestration of Ca2+ results in defective notochord cell intercalation, and pharmacological inhibition to reveal that stretch-activated ion channels (SACs), inositol triphosphate receptor (IP3R) signalling, Store Operated Calcium Entry (SOCE), Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and gap junctions are required for regulating notochord Ca2+ activity during tubulogenesis. Cytoskeletal rearrangements drive the cell shape changes that accompany tubulogenesis. In line with this, we show that Ca2+ signalling modulates reorganization of the cytoskeletal network across the morphogenetic events leading up to and during tubulogenesis of the notochord. We additionally demonstrate that perturbation of the actin cytoskeleton drastically remodels Ca2+ dynamics, suggesting a feedback mechanism between actin dynamics and Ca2+ signalling during notochord development. This work provides a framework to quantitatively define how Ca2+ signalling regulates tubulogenesis using the notochord as model organ, a defining structure of all chordates.

scholarly journals Mutations in the cofilin partner Aip1/Wdr1 cause autoinflammatory disease and macrothrombocytopenia

Blood ◽  
2007 ◽  
Vol 110 (7) ◽  
pp. 2371-2380 ◽  
Author(s):  
Benjamin T. Kile ◽  
Athanasia D. Panopoulos ◽  
Roslynn A. Stirzaker ◽  
Douglas F. Hacking ◽  
Lubna H. Tahtamouni ◽  
...  
Keyword(s):  
Autoinflammatory Disease ◽  
Cell Types ◽  
Actin Dynamics ◽  
Loss Of Function ◽  
Allelic Series ◽  
Interacting Protein ◽  
Normal Platelet ◽  
Cytoskeletal Responses ◽  
Hypomorphic Alleles ◽  
And Function

A pivotal mediator of actin dynamics is the protein cofilin, which promotes filament severing and depolymerization, facilitating the breakdown of existing filaments, and the enhancement of filament growth from newly created barbed ends. It does so in concert with actin interacting protein 1 (Aip1), which serves to accelerate cofilin's activity. While progress has been made in understanding its biochemical functions, the physiologic processes the cofilin/Aip1 complex regulates, particularly in higher organisms, are yet to be determined. We have generated an allelic series for WD40 repeat protein 1 (Wdr1), the mammalian homolog of Aip1, and report that reductions in Wdr1 function produce a dramatic phenotype gradient. While severe loss of function at the Wdr1 locus causes embryonic lethality, macrothrombocytopenia and autoinflammatory disease develop in mice carrying hypomorphic alleles. Macrothrombocytopenia is the result of megakaryocyte maturation defects, which lead to a failure of normal platelet shedding. Autoinflammatory disease, which is bone marrow–derived yet nonlymphoid in origin, is characterized by a massive infiltration of neutrophils into inflammatory lesions. Cytoskeletal responses are impaired in Wdr1 mutant neutrophils. These studies establish an essential requirement for Wdr1 in megakaryocytes and neutrophils, indicating that cofilin-mediated actin dynamics are critically important to the development and function of both cell types.

Hydrogen peroxide attenuates store-operated calcium entry and enhances calcium extrusion in thyroid FRTL-5 cells

2000 ◽  
Vol 351 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Kid TÖRNQUIST ◽  
Petri J. VAINIO ◽  
Sonja BJÖRKLUND ◽  
Alexey TITIEVSKY ◽  
Benoit DUGUÉ ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Types ◽  
Feedback Mechanism ◽  
Calcium Entry ◽  
Reducing Agent ◽  
Free Calcium ◽  
Dependent Manner ◽  
Thyroid Cells ◽  
Store Operated Calcium Entry ◽  
In Cells

Redox modulation participates in the regulation of intracellular free calcium concentration ([Ca2+]i) in several cell types. In thyroid cells, including FRTL-5 cells, changes in [Ca2+]i regulate several important functions, including the production of H2O2 (hydrogen peroxide). As H2O2 is of crucial importance for the production of thyroid hormones, we investigated the effects of H2O2 on [Ca2+]i in thyroid FRTL-5 cells. H2O2 itself did not modulate basal [Ca2+]i. However, H2O2 attenuated store-operated calcium entry evoked by thapsigargin, both in a sodium-containing buffer and in a sodium-free buffer. The effect of H2O2 was abrogated by the reducing agent β-mercaptoethanol. H2O2 also attenuated the thapsigargin-evoked entry of barium and manganese. The effect of H2O2 was, at least in part, mediated by activation of protein kinase C (PKC), as H2O2 enhanced the binding of [3H]phorbol 12,13-dibutyrate. H2O2 also stimulated the translocation of the isoenzyme PKCε from the cytosolic fraction to the particulate fraction. Furthermore, H2O2 did not attenuate store-operated calcium entry in cells treated with staurosporine or calphostin C, or in cells with down-regulated PKC. H2O2 depolarized the membrane potential in bisoxonol-loaded cells and when patch-clamp in the whole-cell mode was used. The depolarization was attenuated in cells with down-regulated PKC. This depolarization, at least in part, explained the H2O2-evoked inhibition of calcium entry. In addition, H2O2 enhanced the extrusion of calcium from cells stimulated with thapsigargin and this effect was abolished in cells with down-regulated PKC and after treatment of the cells with the reducing agent β-mercaptoethanol. In conclusion H2O2 attenuates an increase in [Ca2+]i. As H2O2 is produced in thyroid cells in a calcium-dependent manner, our results suggest that H2O2 may participate in the regulation of [Ca2+]i in these cells via a negative-feedback mechanism involving activation of PKC.

scholarly journals The Roles of Primary Cilia in Cardiovascular Diseases

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 233 ◽  
Author(s):  
Rajasekharreddy Pala ◽  
Maha Jamal ◽  
Qamar Alshammari ◽  
Surya Nauli
Keyword(s):  
Cardiovascular Diseases ◽  
Primary Cilia ◽  
Cell Types ◽  
Molecular Defects ◽  
Flow Sensing ◽  
Intracellular Signals ◽  
Wide Range ◽  
No Signaling ◽  
Vascular Endothelia ◽  
And Function

Primary cilia are microtubule-based organelles found in most mammalian cell types. Cilia act as sensory organelles that transmit extracellular clues into intracellular signals for molecular and cellular responses. Biochemical and molecular defects in primary cilia are associated with a wide range of diseases, termed ciliopathies, with phenotypes ranging from polycystic kidney disease, liver disorders, mental retardation, and obesity to cardiovascular diseases. Primary cilia in vascular endothelia protrude into the lumen of blood vessels and function as molecular switches for calcium (Ca2+) and nitric oxide (NO) signaling. As mechanosensory organelles, endothelial cilia are involved in blood flow sensing. Dysfunction in endothelial cilia contributes to aberrant fluid-sensing and thus results in vascular disorders, including hypertension, aneurysm, and atherosclerosis. This review focuses on the most recent findings on the roles of endothelial primary cilia within vascular biology and alludes to the possibility of primary cilium as a therapeutic target for cardiovascular disorders.

scholarly journals Structure and function of the immune system in the spleen

2019 ◽  
Vol 4 (33) ◽  
pp. eaau6085 ◽  
Author(s):  
Steven M. Lewis ◽  
Adam Williams ◽  
Stephanie C. Eisenbarth
Keyword(s):  
Cell Types ◽  
Structure And Function ◽  
Lymphoid Organ ◽  
The Body ◽  
Human Spleen ◽  
Cell Clearance ◽  
Wide Range ◽  
Abnormal Cells ◽  
Cell Organization ◽  
And Function

The spleen is the largest secondary lymphoid organ in the body and, as such, hosts a wide range of immunologic functions alongside its roles in hematopoiesis and red blood cell clearance. The physical organization of the spleen allows it to filter blood of pathogens and abnormal cells and facilitate low-probability interactions between antigen-presenting cells (APCs) and cognate lymphocytes. APCs specific to the spleen regulate the T and B cell response to these antigenic targets in the blood. This review will focus on cell types, cell organization, and immunologic functions specific to the spleen and how these affect initiation of adaptive immunity to systemic blood-borne antigens. Potential differences in structure and function between mouse and human spleen will also be discussed.

scholarly journals Bone Anabolic Effects of Soluble Si:In VitroStudies with Human Mesenchymal Stem Cells and CD14+ Osteoclast Precursors

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
J. Costa-Rodrigues ◽  
S. Reis ◽  
A. Castro ◽  
M. H. Fernandes
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Plasma Levels ◽  
Human Mesenchymal Stem Cells ◽  
Cell Types ◽  
Osteoclast Precursors ◽  
Wide Range ◽  
Basal Plasma ◽  
Important Player ◽  
And Function

Silicon (Si) is indispensable for many cellular processes including bone tissue metabolism. In this work, the effects of Si on human osteogenesis and osteoclastogenesis were characterized. Human mesenchymal stem cells (hMSC) and CD14+ stem cells, as osteoblast and osteoclast precursors, were treated with a wide range of Si concentrations, covering the physiological plasma levels. Si promoted a dose-dependent increase in hMSC proliferation, differentiation, and function, at levels similar to the normal basal plasma levels. Additionally, a decrease in the expression of the osteoclastogenic activators M-CSF and RANKL was observed. Also, Si elicited a decrease in osteoclastogenesis, which became significant at higher concentrations, as those observed after meals. Among the intracellular mechanisms studied, an upregulation of MEK and PKC signalling pathways was observed in both cell types. In conclusion, Si appears to have a direct positive effect on human osteogenesis, at basal plasma levels. On the other hand, it also seemed to be an inhibitor of osteoclastogenesis, but at higher concentrations, though yet in the physiological range. Further, an indirect effect of Si on osteoclastogenesis may also occur, through a downregulation of M-CSF and RANKL expression by osteoblasts. Thus, Si may be an important player in bone anabolic regenerative approaches.

scholarly journals Morphology and function of three VIP-expressing amacrine cell types in the mouse retina

2015 ◽  
Vol 114 (4) ◽  
pp. 2431-2438 ◽  
Author(s):  
Alejandro Akrouh ◽  
Daniel Kerschensteiner
Keyword(s):  
Mammalian Species ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell Types ◽  
Mouse Retina ◽  
Inner Plexiform Layer ◽  
Light Responses ◽  
Wide Range ◽  
Asymmetric Distributions ◽  
And Function

Amacrine cells (ACs) are the most diverse class of neurons in the retina. The variety of signals provided by ACs allows the retina to encode a wide range of visual features. Of the 30–50 AC types in mammalian species, few have been studied in detail. Here, we combine genetic and viral strategies to identify and to characterize morphologically three vasoactive intestinal polypeptide-expressing GABAergic AC types (VIP1-, VIP2-, and VIP3-ACs) in mice. Somata of VIP1- and VIP2-ACs reside in the inner nuclear layer and somata of VIP3-ACs in the ganglion cell layer, and they show asymmetric distributions along the dorsoventral axis of the retina. Neurite arbors of VIP-ACs differ in size (VIP1-ACs ≈ VIP3-ACs > VIP2-ACs) and stratify in distinct sublaminae of the inner plexiform layer. To analyze light responses and underlying synaptic inputs, we target VIP-ACs under 2-photon guidance for patch-clamp recordings. VIP1-ACs depolarize strongly to light increments (ON) over a wide range of stimulus sizes but show size-selective responses to light decrements (OFF), depolarizing to small and hyperpolarizing to large stimuli. The switch in polarity of OFF responses is caused by pre- and postsynaptic surround inhibition. VIP2- and VIP3-ACs both show small depolarizations to ON stimuli and large hyperpolarizations to OFF stimuli but differ in their spatial response profiles. Depolarizations are caused by ON excitation outweighing ON inhibition, whereas hyperpolarizations result from pre- and postsynaptic OFF-ON crossover inhibition. VIP1-, VIP2-, and VIP3-ACs thus differ in response polarity and spatial tuning and contribute to the diversity of inhibitory and neuromodulatory signals in the retina.

TRPC1: a core component of store-operated calcium channels

2007 ◽  
Vol 35 (1) ◽  
pp. 96-100 ◽  
Author(s):  
I.S. Ambudkar
Keyword(s):  
Calcium Release ◽  
Transient Receptor Potential ◽  
Calcium Signalling ◽  
Receptor Potential ◽  
Cell Types ◽  
Surface Expression ◽  
Membrane Microdomains ◽  
Store Operated Calcium Entry ◽  
Transient Receptor ◽  
And Function

The TRPC (transient receptor potential canonical) proteins are activated in response to agonist-stimulated PIP2 (phosphatidylinositol 4,5-bisphosphate) hydrolysis and have been suggested as candidate components of the elusive SOC (store-operated calcium channel). TRPC1 is currently the strongest candidate component of SOC. Endogenous TRPC1 has been shown to contribute to SOCE (store-operated calcium entry) in several different cell types. However, the mechanisms involved in the regulation of TRPC1 and its exact physiological function have yet to be established. Studies from our laboratory and several others have demonstrated that TRPC1 is assembled in a signalling complex with key calcium signalling proteins in functionally specific plasma membrane microdomains. Furthermore, critical interactions between TRPC1 monomers as well as interactions between TRPC1 and other proteins determine the surface expression and function of TRPC1-containing channels. Recent studies have revealed novel regulators of TRPC1-containing SOCs and have demonstrated a common molecular basis for the regulation of CRAC (calcium-release-activated calcium) and SOC channels. In the present paper, we will revisit the role of TRPC1 in SOCE and discuss how studies with TRPC1 provide an experimental basis for validating the mechanism of SOCE.

Transcriptional activity of MEF2 during mouse embryogenesis monitored with a MEF2-dependent transgene

Development ◽  
1999 ◽  
Vol 126 (10) ◽  
pp. 2045-2052 ◽  
Author(s):  
F.J. Naya ◽  
C. Wu ◽  
J.A. Richardson ◽  
P. Overbeek ◽  
E.N. Olson
Keyword(s):  
Dna Sequences ◽  
Transcriptional Activity ◽  
Cell Types ◽  
Neural Cell ◽  
Adult Brain ◽  
Mouse Embryogenesis ◽  
Cell Lineages ◽  
Nonmuscle Cell ◽  
Wide Range ◽  
Flanking Sequences

The four members of the MEF2 family of MADS-box transcription factors, MEF2-A, MEF2-B, MEF2-C and MEF2-D, are expressed in overlapping patterns in developing muscle and neural cell lineages during embryogenesis. However, during late fetal development and postnatally, MEF2 transcripts are also expressed in a wide range of cell types. Because MEF2 expression is controlled by translational and post-translational mechanisms, it has been unclear whether the presence of MEF2 transcripts in the embryo reflects transcriptionally active MEF2 proteins. To define the temporospatial expression pattern of transcriptionally active MEF2 proteins during mouse embryogenesis, we generated transgenic mice harboring a lacZ reporter gene controlled by three tandem copies of the MEF2 site and flanking sequences from the desmin enhancer, which is active in cardiac, skeletal and smooth muscle cells. Expression of this MEF2-dependent transgene paralleled expression of MEF2 mRNAs in developing myogenic lineages and regions of the adult brain. However, it was not expressed in other cell types that express MEF2 transcripts. Tandem copies of the MEF2 site from the c-jun promoter directed expression in a similar pattern to the desmin MEF2 site, suggesting that transgene expression reflects the presence of transcriptionally active MEF2 proteins, rather than other factors specific for DNA sequences flanking the MEF2 site. These results demonstrate the presence of transcriptionally active MEF2 proteins in the early muscle and neural cell lineages during embryogenesis and argue against the existence of lineage-restricted MEF2 cofactors that discriminate between MEF2 sites with different immediate flanking sequences. The discordance between MEF2 mRNA expression and MEF2 transcriptional activity in nonmuscle cell types of embryos and adults also supports the notion that post-transcriptional mechanisms regulate the expression of MEF2 proteins.

DNA Methylation Abnormality and Brain Dysfunction of Neural Stem Cells Caused by Chronic Inflammation by Nanoparticle Exposure

Impact ◽  
2020 ◽  
Vol 2020 (7) ◽  
pp. 28-30
Author(s):  
Ken Tachibana
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Neural Development ◽  
Broad Class ◽  
Cell Types ◽  
Associate Professor ◽  
Adult Brain ◽  
Wide Range ◽  
The Creation ◽  
The Brain

The biological development of a human is an extremely complex and delicate process. It starts from fertilisation and continues until long after birth. The creation and development of the brain is particularly complicated and susceptible to disruptions to its progression. The primary cells responsible for the development of the brain are the neural stem cells. These are a broad class of cells that can differentiate into the wide range of cell types that form the adult brain. To achieve this complex process, different cells need to undergo a range of gene expression changes at the right time. This is delicate and its disturbance is a key cause of pathology in a wide range of diseases. There are many external factors that are known to disrupt neural development however, there are several common chemicals whose effects remain largely unknown. One such group are broadly described as nanoparticles. These are small particles that are being increasingly used by many industries as they can help in the creation of products with better properties. However, their effect on the environment and the human body – particularly that of a developing brain – have been largely unexamined. Associate Professor Ken Tachibana of the Division of Hygienic Chemistry, Sanyo-Onoda City University, Japan is researching the effects of nanoparticles on neural development.

scholarly journals Flagellar Synchronization Is a Simple Alternative to Cell Cycle Synchronization for Ciliary and Flagellar Studies

mSphere ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Soumita Dutta ◽  
Prachee Avasthi
Keyword(s):  
Cell Cycle ◽  
Chlamydomonas Reinhardtii ◽  
Cell Types ◽  
Model System ◽  
Content Type ◽  
Cell Synchronization ◽  
Cilium Formation ◽  
Wide Range ◽  
Cilia And Flagella ◽  
And Function

ABSTRACT Cilia and flagella are highly conserved antenna-like organelles that found in nearly all mammalian cell types. They perform sensory and motile functions contributing to numerous physiological and developmental processes. Defects in their assembly and function are implicated in a wide range of human diseases ranging from retinal degeneration to cancer. Chlamydomonas reinhardtii is an algal model system for studying mammalian cilium formation and function. Here, we report a simple synchronization method that allows detection of small changes in ciliary length by minimizing variability in the population. We find that this method alters the key relationship between cell size and the amount of protein accumulated for flagellar growth. This provides a rapid alternative to traditional methods of cell synchronization for uncovering novel regulators of cilia. The unicellular green alga Chlamydomonas reinhardtii is an ideal model organism for studies of ciliary function and assembly. In assays for biological and biochemical effects of various factors on flagellar structure and function, synchronous culture is advantageous for minimizing variability. Here, we have characterized a method in which 100% synchronization is achieved with respect to flagellar length but not with respect to the cell cycle. The method requires inducing flagellar regeneration by amputation of the entire cell population and limiting regeneration time. This results in a maximally homogeneous distribution of flagellar lengths at 3 h postamputation. We found that time-limiting new protein synthesis during flagellar synchronization limits variability in the unassembled pool of limiting flagellar protein and variability in flagellar length without affecting the range of cell volumes. We also found that long- and short-flagella mutants that regenerate normally require longer and shorter synchronization times, respectively. By minimizing flagellar length variability using a simple method requiring only hours and no changes in media, flagellar synchronization facilitates the detection of small changes in flagellar length resulting from both chemical and genetic perturbations in Chlamydomonas. This method increases our ability to probe the basic biology of ciliary size regulation and related disease etiologies. IMPORTANCE Cilia and flagella are highly conserved antenna-like organelles that found in nearly all mammalian cell types. They perform sensory and motile functions contributing to numerous physiological and developmental processes. Defects in their assembly and function are implicated in a wide range of human diseases ranging from retinal degeneration to cancer. Chlamydomonas reinhardtii is an algal model system for studying mammalian cilium formation and function. Here, we report a simple synchronization method that allows detection of small changes in ciliary length by minimizing variability in the population. We find that this method alters the key relationship between cell size and the amount of protein accumulated for flagellar growth. This provides a rapid alternative to traditional methods of cell synchronization for uncovering novel regulators of cilia.

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