scholarly journals Membrane cholesterol regulates TRPV4 function, cytoskeletal expression, and the cellular response to tension

2021 ◽  
pp. 100145
Author(s):  
Monika Lakk ◽  
Grace F. Hoffmann ◽  
Aruna Gorusupudi ◽  
Eric Enyong ◽  
Amy Lin ◽  
...  
Keyword(s):  
Cellular Response ◽  
Membrane Cholesterol

scholarly journals Membrane cholesterol regulates TRPV4 function, cytoskeletal expression and the cellular response to tension

2020 ◽  
Author(s):  
Monika Lakk ◽  
Grace F. Hoffmann ◽  
Aruna Gorusupudi ◽  
Paul S. Bernstein ◽  
Trine Toft-Bertelsen ◽  
...  
Keyword(s):  
Protein Function ◽  
Cellular Response ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Cyclic Stretch ◽  
Membrane Cholesterol ◽  
Cholesterol Depletion ◽  
Transient Receptor Potential Vanilloid ◽  
Membrane Expression ◽  
Cholesterol Levels

AbstractCholesterol plays important roles in the regulation of membrane viscoelasticity, protein function and cellular health but despite its association with debilitating pressure-related diseases its role in mechanotransduction is not well understood. Here, we investigated how alterations in membrane cholesterol levels impact activation of TRPV4 (transient receptor potential vanilloid isoform 4), a stretch-activated cation channel, in trabecular meshwork (TM) cells that control intraocular pressure in the mammalian eye. Human TM cells responded to pharmacological depletion of free membrane cholesterol with augmented TRPV4 activation by agonist GSK1016790A, swelling and strain, and by increased membrane expression of TRPV4 immunoreactivity. Cyclic stretch increased the membrane cholesterol/phosphatidylcholine ratio and upregulated expression of F-actin, with the low-cholesterol effects reversed by cholesterol supplementation. Cholesterol depletion induced a constitutive current in TRPV4-expressing Xenopus laevis oocytes and obviated its activation by hypotonic swelling. Taken together, these findings suggest that cholesterol regulates translocation and activation of TRPV4, and guides its participation in macromolecular complexes, cytoskeletal architecture and cell-matrix contacts; in turn membrane cholesterol levels are dynamically regulated by the biomechanical milieu. By regulating TM pressure sensitivity, calcium homeostasis and contractility, cholesterol-TRPV4 interactions could influence IOP homeostasis and its role in glaucoma and diabetes.

Caveolin-1, galectin-3 and lipid raft domains in cancer cell signalling

2015 ◽  
Vol 57 ◽  
pp. 189-201 ◽  
Author(s):  
Jay Shankar ◽  
Cecile Boscher ◽  
Ivan R. Nabi
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Cancer Cell ◽  
Cellular Response ◽  
Spatial Organization ◽  
Essential Feature ◽  
Cell Signalling ◽  
Coated Pits ◽  
Signalling Molecules ◽  
Raft Domains

Spatial organization of the plasma membrane is an essential feature of the cellular response to external stimuli. Receptor organization at the cell surface mediates transmission of extracellular stimuli to intracellular signalling molecules and effectors that impact various cellular processes including cell differentiation, metabolism, growth, migration and apoptosis. Membrane domains include morphologically distinct plasma membrane invaginations such as clathrin-coated pits and caveolae, but also less well-defined domains such as lipid rafts and the galectin lattice. In the present chapter, we will discuss interaction between caveolae, lipid rafts and the galectin lattice in the control of cancer cell signalling.

Mechanisms of Signaling through Urokinase Receptor and the Cellular Response

1999 ◽  
Vol 82 (08) ◽  
pp. 305-311 ◽  
Author(s):  
Yuri Koshelnick ◽  
Monika Ehart ◽  
Hannes Stockinger ◽  
Bernd Binder
Keyword(s):  
Cell Surface ◽  
Proteolytic Activity ◽  
Tumor Invasion ◽  
Cellular Response ◽  
Transmembrane Protein ◽  
Urokinase Receptor ◽  
Biological Processes ◽  
In Vivo Models ◽  
Proteolytic Activation ◽  
Core Proteins

IntroductionThe urokinase-urokinase receptor (u-PA-u-PAR) system seems to play a crucial role in a number of biological processes, including local fibrinolysis, tumor invasion, angiogenesis, neointima and atherosclerotic plaque formation, inflammation, and matrix remodeling during wound healing and development.1-6 Binding of urokinase to its specific receptor provides cells with a localized proteolytic potential. It stimulates conversion of cell surface-bound plasminogen into active plasmin, which, in turn, is required for proteolytic degradation of basement membrane components, including fibronectin, collagen, laminin, and proteoglycan core proteins.7 Moreover, plasmin activates other matrix-degrading enzymes, such as matrix metalloproteinases.8 Overexpression of u-PA/u-PAR correlates with tumor invasion and metastasis formation,9-13 while reduction of cell-surface bound u-PA and inhibition of u-PAR expression leads to a significant decrease of invasive and metastatic activity.14 Specific antagonists that suppress binding of u-PA to u-PAR have been shown to inhibit cell-surface plasminogen activation, tumor growth, and angiogenesis both in vitro and in vivo models.15,16 Independently of its proteolytic activity, u-PA is implicated in many biological processes that seem to require u-PAR-mediated intracellular signal transduction, such as proliferation, chemotactic movement and adhesion, migration, and differentiation.17 Data obtained in the late 1980s indicated that u-PA not only provides cells with local proteolytic activity, but might also be capable of transducing signals to the cell.18-22 At that time, however, the u-PAR has just been isolated, cloned, and identified as a glycosylphosphatidylinositol (GPI)-linked protein and not a transmembrane protein. Signaling via the u-PAR was, therefore, regarded as being unlikely, and the effects of u-PA on cell proliferation18-22 were thought to be mediated by proteolytic activation of latent growth factors. The assumption of direct signaling via u-PAR was, in fact, considered controversial, until about 10 years later when a physical association between u-PAR and signaling proteins was found.23 From this report on, several proteins associated with u-PAR have been identified. Now, u-PAR seems to be part of a large “signalosome” associated and interacting with several proteins on both the outside and inside of the cell.

Apoptosis and proliferation ofperipheral blood T-cells as alternative processes in pathogenesis of diabetes mellitus type 1

2019 ◽  
Vol 1 (4) ◽  
pp. 16-20 ◽  
Author(s):  
A. V. Lugovaya ◽  
N. M. Kalinina ◽  
V. Ph. Mitreikin ◽  
Yu. P. Kovaltchuk ◽  
A. V. Artyomova ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
T Cells ◽  
High Risk ◽  
Peripheral Blood ◽  
Cellular Response ◽  
Proliferative Potential ◽  
Autoreactive T Cells ◽  
Alternative Processes

Apoptosis, along with proliferation, is a form of lymphocyte response to activating stimuli. In the early stages of cell differentiation, the apoptotic response prevails and it results to the formation of tolerance to inductor antigen. Mature lymphocytes proliferate in response to stimulation and it means the initial stage in the development of the immune response. Since in this case apoptosis and proliferation acts as alternative processes, their ratio can serve as a measure of the effectiveness of the cellular response to activating signals. The resistance of autoreactive T-cells to apoptosis is the main key point in the development of type 1 diabetes mellitus (T1DM). Autoreactive T-cells migrates from the bloodstream to the islet tissue of the pancreas and take an active part in b cells destruction. The resistance of autoreactive effector T-cells to apoptosis may suggest their high proliferative potential. Therefore, the comparative evaluation of apoptosis and proliferation of peripheral blood lymphocytes can give a more complete picture of their functional state and thus will help to reveal the causes of ineffective peripheral blood T-ceiis apoptosis in patients with T1DM and will help to understand more deeply the pathogenesis of the disease. in this article, the features of proliferative response of peripheral blood T-cells in patients with T1DM and in individuals with high risk of developing T1DM have been studied. Apoptosis of T-cell subpopulations has been investigated. The correlation between the apoptotic markers and the intensity of spontaneous and activation- induced in vitro T-cells proliferation of was revealed. it was determined, that autoreactive peripheral blood T-cells were resistant to apoptosis and demonstrated the increased proliferative potential in patients with T1DM and in individuals with high risk of developing T1DM.

Study of the radiomodifier effect of Pityrocarpa moniliformis extract

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
João Victor Torres de Moraes ◽  
Ricardo Luiz Calazans Luna Filho ◽  
Williams Nascimento de Siqueira ◽  
Hianna Arely Milca Fagundes Silva ◽  
Dewson Rocha Pereira ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Cellular Response ◽  
Biomphalaria Glabrata ◽  
Toxicity Tests ◽  
Antioxidant Compounds ◽  
Blastula Stage ◽  
Natural Substances ◽  
60Co Source ◽  
60Co Gamma ◽  
60Co Gamma Radiation

Ionizing radiation has been applied in several areas of knowledge, among them the study of the radiomodifier activity of natural substances. These substances can modify the cellular response to the damage induced by the radiation. Therefore, this work aimed to evaluate the radiomodifier action of Pityrocarpa moniliformis extract on Biomphalaria glabrata embryos exposed to 60Co gamma radiation. Initially, toxicity tests were performed on the extract against the B. glabrata embryos for the choice of concentration that did not cause death and embryonic malformation. Then, the antioxidant activity of the P. moniliformis extract with flavonoids and phenolic compounds was evaluated by means of the ABTS method. To evaluate the radiomodifier activity of the extract, embryos were selected in the blastula stage and irradiated with 7.5 Gy in a 60Co source (gammacell-Co60). Then, the embryos were exposed for 24 h to the extract of P. moniliformis at a concentration of 250 μg/mL. The results showed that the extract of P. moniliformis presents flavonoids and enzymatic inhibition by ABTS, which demonstrates the presence of antioxidant compounds. However, the tests of the radiomodifier activity did not present radioprotective effect for embryos exposed to ionizing radiation.

Use of Flexible Materials with a Novel Pressure Driven Equibiaxial Cell Stretching Device for Mechanical Stimulation of Single Mammalian Cells

2003 ◽  
Vol 773 ◽  
Author(s):  
James D. Kubicek ◽  
Stephanie Brelsford ◽  
Philip R. LeDuc
Keyword(s):  
Cell Fate ◽  
Mechanical Stimulation ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Single Cells ◽  
Complex Nature ◽  
Cellular Behavior ◽  
Cell Stretching ◽  
Stimulation Of ◽  
Pressure Driven

AbstractMechanical stimulation of single cells has been shown to affect cellular behavior from the molecular scale to ultimate cell fate including apoptosis and proliferation. In this, the ability to control the spatiotemporal application of force on cells through their extracellular matrix connections is critical to understand the cellular response of mechanotransduction. Here, we develop and utilize a novel pressure-driven equibiaxial cell stretching device (PECS) combined with an elastomeric material to control specifically the mechanical stimulation on single cells. Cells were cultured on silicone membranes coated with molecular matrices and then a uniform pressure was introduced to the opposite surface of the membrane to stretch single cells equibiaxially. This allowed us to apply mechanical deformation to investigate the complex nature of cell shape and structure. These results will enhance our knowledge of cellular and molecular function as well as provide insights into fields including biomechanics, tissue engineering, and drug discovery.

Single Cell Based Microelectrode Array Biosensors

2003 ◽  
Vol 773 ◽  
Author(s):  
Mo Yang ◽  
Shalini Prasad ◽  
Xuan Zhang ◽  
Mihrimah Ozkan ◽  
Cengiz S. Ozkan
Keyword(s):  
Electrical Activity ◽  
Single Cell ◽  
Cellular Response ◽  
Microelectrode Array ◽  
Fast Fourier Transformation ◽  
Chemical Agent ◽  
Extracellular Potential ◽  
Membrane Excitability ◽  
Specific Chemical ◽  
Chemical Agents

AbstractExtracellular potential is an important parameter which indicates the electrical activity of live cells. Membrane excitability in osteoblasts plays a key role in modulating the electrical activity in the presence of chemical agents. The complexity of cell signal makes interpretation of the cellular response to a chemical agent very difficult. By analyzing shifts in the signal power spectrum, it is possible to determine a frequency spectrum also known as Signature Pattern Vectors (SPV) specific to a chemical. It is also essential to characterize single cell sensitivity and response time for specific chemical agents for developing detect-to-warn biosensors. We used a 4x4 multiple Pt microelectrode array to spatially position single osteoblast cells, by using a gradient AC field. Fast Fourier Transformation (FFT) and Wavelet Transformation (WT) analyses were used to extract information pertaining to the frequency of firing from the extracellular potential.

A Photoactivatable α5β1-Specific Integrin Ligand

2018 ◽  
Author(s):  
Roshna Vakkeel ◽  
Aleeza Farrukh ◽  
Aranzazu del Campo
Keyword(s):  
Cellular Response ◽  
Light Exposure ◽  
Matrix Composition ◽  
Cellular Behavior ◽  
Dynamic Variations ◽  
In Situ Activation ◽  
Controlled Exposure ◽  
Cellular Behaviour ◽  
Integrin Ligand

In order to study how dynamic changes of α5β1 integrin engagement affect cellular behaviour, photoactivatable derivatives of α5β1 specific ligands are presented in this article. The presence of the photoremovable protecting group (PRPG) introduced at a relevant position for integrin recognition, temporally inhibits ligand bioactivity. Light exposure at cell-compatible dose efficiently cleaves the PRPG and restores functionality. Selective cell response (attachment, spreading, migration) to the activated ligand on the surface is achieved upon controlled exposure. Spatial and temporal control of the cellular response is demonstrated, including the possibility to in situ activation. Photoactivatable integrin-selective ligands in model microenvironments will allow the study of cellular behavior in response to changes in the activation of individual integrins as consequence of dynamic variations of matrix composition.

Prime-editors (nickases), hRad51–Cas9 nickase fusions and dCas9 have the same problem as conventional CRISPR-Cas9 of plasmid/Cas9 integration after making a double stranded break

2019 ◽  
Author(s):  
Sandeep Chakraborty
Keyword(s):  
Cellular Response ◽  
Sequencing Data ◽  
Dna Breaks ◽  
Precise Integration ◽  
Guide Rna ◽  
Double Strand Dna Breaks ◽  
Human Therapy ◽  
P53 Activation ◽  
Programmable Nucleases

‘Prime-editing’ proposes to replace traditional programmable nucleases (CRISPR-Cas9) using a catalytically impaired Cas9 (dCas9) connected to a engineered reverse transcriptase, and a guide RNA encoding both the target site and the desired change. With just a ‘nick’ on one strand, it is hypothe- sized, the negative, uncontrollable effects arising from double-strand DNA breaks (DSBs) - translocations, complex proteins, integrations and p53 activation - will be eliminated. However, sequencing data pro- vided (Accid:PRJNA565979) reveal plasmid integration, indicating that DSBs occur. Also, looking at only 16 off-targets is inadequate to assert that Prime-editing is more precise. Integration of plasmid occurs in all three versions (PE1/2/3). Interestingly, dCas9 which is known to be toxic in E. coli and yeast, is shown to have residual endonuclease activity. This also affects studies that use dCas9, like base- editors and de/methylations systems. Previous work using hRad51–Cas9 nickases also show significant integration in on-targets, as well as off-target integration [1]. Thus, we show that cellular response to nicking involves DSBs, and subsequent plasmid/Cas9 integration. This is an unacceptable outcome for any in vivo application in human therapy.

Sign in / Sign up

Export Citation Format

Share Document