examples of cellular responses


Steven G. Gray, in Epigenetics in Human Disease, 2012. All rights reserved. Impaired G-protein-coupled receptor signaling, responsible for most of the complications associated with obesity and cardiovascular disorders, activates the MAPK pathway, which ultimately activates downstream transcription factors and gene expression related to cardiac growth. Calcium imaging, or monitoring changes in intracellular calcium, is an extremely useful technique for investigating the variety of roles that calcium ions have in, Reporter genes are valuable tools for studying gene expression, serving as surrogates for genes involved in various signaling pathways and disease conditions., G-Protein Coupled Receptors (GPCRs) are important transmembrane proteins that translate extracellular signals into intracellular responses. CHOP (C/EBP Homologous Protein) is an ER stress-inducible protein which plays a critical role in regulating programmed cell death. A similar genomic library enrichment strategy has been used to successfully identify beneficial genetic traits in E. coli139 and S. cerevisiae.140 Eleven beneficial genes identified in E. coli are able to confer butanol tolerance by overexpression from a plasmid.139 The genes found to confer the strongest alcohol tolerance from plasmid-based overexpression are entC and feoA, which are related to iron metabolism and transport.139 Overexpression of entC and feoA increased the butanol tolerance by 32.8% and 49.1%, respectively.139 Four native S. cerevisiae genes related to isobutanol tolerance have also been identified by the genomic plasmid library enrichment approach.140 Overexpression of the genes encoding INO1 (inositol-1-phosphate synthase), DOG1 (2-deoxyglucose-6-phosphatase), HAL1 (involved in halotolerance), or a truncated form of MSN2 (a stress-responsive transcriptional activator) resulted in increased tolerance to high concentrations of isobutanol.140 The molecular mechanisms of alcohol tolerance conferred by overexpression of these genes remain to be elucidated. Aligned nanofibrous structures for potential use in blood vessel engineering have been proven to control the migration of smooth muscle cells along the axis of aligned nanofibres (Xu et al., 2004). Apr 12, 2022 The half-maximal concentration (EC50) value is directly related to the notion of inhibition of a target; in particular, the EC50 values correspond to the amount of a compound needed to deactivate via phosphorylation 50% of the population of the associated target. This process also involves platelet adherence and degranulation with release of several growth factors (e.g., FGF-2, PDGF, TGF-) into a fibrin meshwork. Specifically, our past results suggest that cell mechanical behaviors are determined at the level of integrative lattice properties and are governed by the prestress borne by the CSK. Time-dependent concentrations of cytokines accompany this very well-balanced sequence of inflammation, remodelling, and maturation in the healing tissue. Topographical cues, such as surface ridges and roughness, not only aid cell alignment but can also affect cell morphology and phenotype (Hasirci et al., 2006). Three different kinases, known as extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs), and p38 MAPKs, are activated by dual phosphorylation on both threonine and tyrosine residues within a Thr-Xaa-Tyr motif. The processes involved include the phenomena of osteoinduction, osteoconduction and osseointegration, resulting in new bone formation, union and incorporation between graft and host, leading to a skeletal tissue environment which is biologically and mechanically matched to the original.

In this chapter, we first review the key role that cell shape and mechanics play in control of cell function, and how cell shape stability is controlled through cellsubstrate interactions. A fully grown plant cell may retain its primary cell wall (sometimes thickening it), or it may deposit an additional, rigidifying layer of different composition; this is the secondary wall. Learn how scientists are advancing discovery with our products and solutions. With the ability to process these signals, cells can interact with each other and the environment. This can allow calcium ions to enter the cytoplasm from the extracellular space, where their concentration is higher. Another arm of this pathway is monitored using a TR-FRET assay for IP1. Some receptors enter the cell still bound to the chemical signal. Understanding and controlling the cellular response to bone graft materials will achieve the positive desired biological interaction between graft material and host site. In addition, CHOP itself directly associates with the histone acetyltransferase KAT3B (p300) to regulate gene expression responses in response to ER stress [226], and importantly, inhibition of HDACs prevents the degradation of the CHOP protein [226]. cell injury aging atrophy death hyperplasia metaplasia hypertrophy dysplasia cellular adaptive responses figure basicmedicalkey This repressor protein has been shown to directly associate with histone deacetylases to repress transcription [230], and this may indicate that BLIMP-1 may utilize histone deacetylases to repress important genes during ER stress.

These observations are consistent with the idea that the CSK is organized as a tensegrity structure; this mechanical, stress-supported network maintains its structural stability through the agency of tensile prestress (Ingber, 1993, 2003a; Stamenovi et al., 1996; Volokh et al., 2000). This prestress results from the action of tensional forces that are generated in contractile actin microfilaments (active prestress), transmitted over intermediate filaments, and resisted by adhesive tethers to extracellular matrix (ECM), known as focal adhesions (FAs), to neighboring cells through cellcell junctions, and by other CSK filaments (e.g., microtubules) inside the cell. Create your account today to get full access to integrated content and world-class customer service. Although the mechanical properties of cells govern their form and function and, when abnormal, lead to a wide range of diseases (Ingber, 2003b), little is known about the linked biophysical and biochemical mechanisms by which cells control their deformability. In a consequence, the lack of the head-to-head data has been recognised the main limitation in our knowledge on the cellular response to biocomposites. The level of inhibition of targets by each drug as measured by EC50s or Kds can be obtained from earlier studies in the literature [99, 100] or from databases such as pubchem (http://pubchem.ncbi.nlm.nih.gov/), Library of Integrated Network-based Cellular Signatures (LINCS) (http://commonfund.nih.gov/lincs/). Cell signaling is the collective name for processes, which cells receive signals, interpret, and respond accordingly. Cellular response is critical for a biocompatibility evaluation of biocomposites both on their road to the medical market and in a research performed in order to develop the new ones. Among the major chaperones that are up-regulated in response to both heat and solvent stresses,109 GroESL overexpression in C.acetobutylicum ATCC 824 has been found to prolong and enhance growth while improving metabolism and solvent production up to 40% higher than the wild type.110,124 In all cases, however, the ability to improve n-butanol production by addressing the tolerance limitation alone has not proven to be the key to enhancing n-butanol production. Mutants conferring tolerance were identified, with the improved tolerance linked to the decreased level of intracellular reactive oxygen species and the up-regulation of stress related genes.132,133 Similarly, a mutant library of novel artificial transcription factors composed of zinc finger DNA-binding proteins fused to E. coli CRP was screened to find the variant conferring n-butanol tolerance in E. coli (up to 1.5%).134, Bacterial efflux pumps have also been engineered to improve solvent tolerance.134136 The AcrAB-TolC efflux system is regarded as a suitable protein engineering target for solvent tolerance. The resorptive process involves focal osteoclasts acting on graft surfaces before bone regeneration is achieved via intramembranous or endochondral ossification. In addition, cell signaling constitutes the foundation of development, immune response, and homeostasis in all organisms. A complementary approach of genomic plasmid library enrichment is to screen the non-essential gene knockout collections for the gene deletions conferring alcohol tolerance. If your budget is modest, a single-mode reader dedicated to your main application may b, Scientists take many roads to overcoming bottlenecks in workflows. Cells are transfected with a plasmid containing the reporter gene, Protein kinases are central to the regulation of many cellular processes. Mechanical loads, specifically strain, influence bone remodelling and cause bone to physically adapt in relation to the mechanical loads placed across it.98 Experimental studies have suggested that no strain leads to bone resorption and increasing strain positively alters the anabolic activity of osteocytes directly or indirectly.99 Direct effects have been stated to involve strain-induced changes in the shape of processes within osseous cannaliculi. Although wet chemical methods have been widely applied to modify the surface wettability of biomaterials or to generate new functionalities, some major drawbacks should be noted. Such possibilities develop a new perspective on the cell-biocomposites interaction. Automated liquid handling within the, The use of gene reporters such as luciferase permits highly sensitive and nondestructive monitoring of gene expression. The phylogenetic tree depicting the relationships between the human protein kinases is shown in Fig. The following section details how targeting HDACi in particular may be of benefit in the treatment/management of diabetes. 2.15. All cell walls contain two layers, the middle lamella and the primary cell wall, and many cells produce an additional layer, called the secondary wall. Cyclic AMP is a derivative of adenosine triphosphate, the ubiquitous energy-carrying molecule of the cell. Mitogen-activated protein kinases (MAPKs) are responsible for a diverse range of physiological processes in cells including growth, survival, and apoptosis. L BOSWORTH, S DOWNES, in Cellular Response to Biomaterials, 2009. Learn more about luciferase reporter gene assays with these application notes: Evaluating microplate readers doesnt have to be overwhelming. 2004; Stamenovi et al., 2002a, 2004). The prestress is also generated passively by mechanical distension of the cell. (2003) has proven that human cells are able to attach, proliferate and orient themselves on fibres whose diameters are considerably smaller than their own. The action of calcium ions is also brief because they are rapidly pumped out of the cell or bound to intracellular molecules, lowering the cytoplasmic concentration to the state existing before stimulation.

Md Ashraful Alam, Lindsay Brown, in Studies in Natural Products Chemistry, 2012. Next-gen 3D biology lab programs stem cells that differentiate and self-organize into organoid models with higher reproducibility and consistency for screening. In contrast to the permanent stiffness and load-bearing capacity of thick secondary walls, the thin primary walls are capable of serving a structural, supportive role only when the vacuoles within the cell are filled with water to the point that they exert a turgor pressure against the cell wall. This phase is essential for provision of the graft environment with nutrients and cell populations. Luciferase reporter gene assays utilizing luminescent reactions have become a versatile tool for studying gene regulation and cell signaling in both basic research and drug discovery. Turgor-induced stiffening of primary walls is analogous to the stiffening of the sides of a pneumatic tire by air pressure. For example, a workstation including a microplate reader can handle multiple steps, which improves efficiency and adds spee, Calcium imaging, or monitoring changes in intracellular calcium, is an extremely useful technique for investigating the variety of roles that calcium ions have in functioning neurons., Reporter genes are valuable tools for studying gene expression, serving as surrogates for genes involved in various signaling pathways and disease conditions.

PLGA films with nano-structured surface features were developed by treating them in a concentrated NaOH solution (Miller et al., 2004). First, consider your application needs. In addition, the tensegrity model also provides a mechanism to link these integrative system-level properties to changes in forces transferred between distinct load-bearing elements at the molecular level, which is not possible using existing models of cell mechanics. JNKs and p38 MAPKs trigger apoptosis whereas ERKs are responsible for cellular survival in the presence of noxious stimuli. Chen et al. Also, the same chemical signal can trigger different responses in different types of cell. In cancer therapy, this is highly relevant for targeted drugs that target-specific proteins [9397].

Cellular response to materials is dependent on the surrounding interactive environment of mechanical, physicochemical and topographical stimuli (Wong et al., 2004). When the nanofiber-modified PCL was treated with 5M NaOH for 3h, a favorable 3T3 fibroblast cells morphology and strong cell attachment were observed on the modified surface, possibly due to the unique hydrophilic surface topography. Two common intracellular signaling molecules are cyclic AMP and the calcium ion. ScienceDirect is a registered trademark of Elsevier B.V. ScienceDirect is a registered trademark of Elsevier B.V. Role of cellular response in the healing process of tendons and ligaments, Biocompatible three-dimensional scaffolds for tendon tissue engineering using electrospinning, Fabrication of nanofibrous scaffolds for tissue engineering applications, Source: (Illustration reproduced courtesy of Cell Signaling Technology, Inc. (, The Potential of Epigenetic Compounds in Treating Diabetes, CELLULAR TENSEGRITY MODELS AND CELL-SUBSTRATE INTERACTIONS, Engineering Central Metabolism for Production of Higher Alcohol-based Biofuels, Biotechnology for Biofuel Production and Optimization, Cellular response to osteoinductive materials in orthopaedic surgery.

Besides, cells may be engaged in producing biocomposites components. Instead, studies with cultured cells suggest that adherent cells control their mechanical behavior by altering the level of prestress borne by their CSK (Hubmayr et al., 1996; Pourati et al., 1998; Rosenblatt et al., 2004; Stamenovi et al., 2002a, 2004; Wang and Ingber, 1994; Wang et al., 2001, 2002). In addition, gene expression and growth factor levels as a function of time after injury are presented. Because CSK filaments can chemically depolymerize and repolymerize, it was assumed in the past that cells alter their mechanical properties via sol-gel transitions (cf. Intracellular stress mediated via free radical generation and other proinflammatory mediators may activate the MAPKs. Moreover, there is vascular invasion into the graft which may also originate from pre-existing Haversian and Volkmann canal systems. Others activate membrane enzymes, which produce certain intracellular chemical mediators. For anticancer targeted drugs, the targets of interest are usually the kinases and the human Kinome consists of around 518 proteins [98]. Cells are transfected with a plasmid containing the reporter gene and a sequence of interest, typically a promoter or other transcriptional control element. For many years, assays of kinase activity were performed using radioactive isotopes or highly specific antibodies. Cell signaling via G protein-coupled receptors (GPCRs) can be assessed by monitoring the downstream effectors calcium or cyclic AMP (cAMP). Cell surface receptors work in several ways when they are occupied. HDACi can enhance insulin-induced glucose uptake, HDACi such as phenylbutyrate can act as chemical chaperones to alleviate ER stress in the pancreas. G protein-coupled receptor (GPCR) signaling can be studied using assays ranging from calcium flux, which can be monitored using fluorescence dyes, to changes in downstream effector molecules assessed by TR-FRET. The detection of cellular signals and responses can help us elucidate the role of cell-to-cell interactions in diseases. That portion of the membrane containing the aggregated receptors is then taken into the cell, where it fuses with various membrane-bounded organelles in the cytoplasm. The important integral factors within local tissues in the zone of implantation include the vascularity of the graft bed alongside the number and competence of the endothelial and osteo-progenitor cells. To allow for cell wall expansion during growth, primary walls are thinner and less rigid than those of cells that have stopped growing. Polyphenolic compounds possessing strong antioxidant and antiinflammatory properties improve stress-activated disorders such as hypertension, atherosclerosis, cardiac hypertrophy, and remodeling. Changes in this cellular force balance may alter cell deformability by promoting structural rearrangements within the CSK and by altering the dynamic mechanical behavior of individual CSK filaments. How can we help you today? This surface modification method is used not only on 2D film surfaces but also on 3D constructs. The intracellular concentrations of both cyclic AMP and calcium ions are normally very low. 2.15. Cellular signaling allows cells to respond to their environment and communicate with other cells. HTRF is a versatile technology developed by Cisbio Bioassays for detecting biomolecular interactions. In general, most of these phases are orchestrated by a variety of inflammatory mediators such as kinins, prostaglandins, vasoactive amines, nitric oxide, interleukins, complement, angiogenic and growth factors. As previously stated the GR signaling pathway has been shown to be affected by the activities of HDACs and chaperones. Fibroblasts also produce collagen which occurs in response to various stimulatory factors (e.g., TGF-) combined with the response to extent of collagen degradation by factors such as metalloproteinases also released by fibroblasts, as well as macrophages.97 The vascularisation process involves the development of fibrovascular tissue within the graft and in the immediate tissue periphery. In the context of diabetes one of the central regulators of ER stress responses is a glucose-responsive gene, Glucose Regulated Protein 78 (GRP78 or BiP). Firefly luciferase, a 61 kD monomeric protein, is especially, Western blot, imaging, and injectors on one configurable microplate reader, Multi-user microplate readers with a large touchscreen and NFC functionality, Configurable readers with triple-mode cuvette ports, validation tools, and compliance software, Precise optics, fluidic transfer, and assay flexibility on one integrated microplate reader, Sensitive luminometer with programmable injector options for 96- and 384-well microplates. Scar tissue exhibits lower biomechanical properties and is prone to rerupture. Calcium flux in response to Gq protein-coupled receptor activation is commonly monitored in live cells in real time using calcium-sensitive dyes on a fluorescence plate reader. If your budget is modest, a single-mode reader dedicated to your, Scientists take many roads to overcoming bottlenecks in workflows. Direct measurement of the dynamic calcium flux within neuronal networks reveals how neurons process signals from the extracellular space. Polymeric nanofibres in tissue engineered constructs make ideal environments for cells to be able to attach, proliferate and maintain their phenotype. This application note demonstrates the feasibility of measuring intracellular calcium flux in primary rat cortical neurons in a fluorescent microplate format: Reporter gene assays are important tools for studying gene expression associated with the activation of cellular pathways.

In the process, we explain how molecular-scale shifts in force between discrete internal and external load-bearing elements in the CSK and ECM adhesive substrate control the mechanical behavior of the whole cell.

Monitoring changes in intracellular calcium is an extremely useful technique for investigating the variety of roles that calcium ions play in functioning neurons. Our team-oriented corporate culture ensures diversity of thought, perspective, and a strong relationship of trust. Some cAMP assays require other detection modes, such as time-resolved fluorescence.

In fact, individual bundles of microfilaments (stress fibers), intermediate filaments, and microtubules often remain structurally intact for periods of minutes to hours, even though individual subcomponents may bind and unbind to filaments on the outer surface of the bundle. The primary wall is the cellulose-containing layer laid down by cells that are dividing and growing. Aggresomes are a cellular response to misfolded protein accumulation as a consequence of ER stress. This prosurvival ER chaperone is induced under conditions of ER stress, and has been shown to be regulated via histone PTMs and chromatin remodeling through the activities of protein arginine methyltransferases (PRMT1) and K-acetyltransferases (KAT3B) [227]. Electrospun PLLA nanofibrous scaffolds were used as a matrix for mineralization of hydroxyapatite (Zhu et al., 2002). First, consider your application needs. For instance, during cytokeratin aggresome (Mallory bodies) formation in hepatocytes, decreased lysine acetyltransferase and increased histone deacetylase activity was observed [223], while in a model of oxidative stress-induced inclusion formation, treatment with the HDACi 4-phenylbutyrate was found to alleviate the formation of these inclusions [224]. Such functions include: (1) providing the protoplast, or living cell, with mechanical protection and a chemically buffered environment, (2) providing a porous medium for the circulation and distribution of water, minerals, and other small nutrient molecules, (3) providing rigid building blocks from which stable structures of higher order, such as leaves and stems, can be produced, and (4) providing a storage site of regulatory molecules that sense the presence of pathogenic microbes and control the development of tissues. The action of cyclic AMP is brief because it is rapidly degraded by specific enzymes. Many previous sophisticated attempts to develop a comprehensive model of cell rheology have typically focused on examining only specific molecular mechanisms or individual types of cytoskeletal components, while disregarding the architectural organization of the whole cytoskeletal network. On the other hand biocomposites may direct cell fate becoming a useful tool in cell-based therapies. (2005) found that aligned nanofibres provided sufficient contact guidance for parallel neural stem cell growth. Thus, for a drug, a target with a lower EC50 is the one that will be heavily inhibited at low drug concentration levels. Other than the description of a drug provided by the chemical descriptors, we can also characterize the drugs in terms of the targets that it inhibits or stimulates. Providing our customers with innovative bioanalytical solutions for protein and cell biology for over 30 years. Immethun, T.S. The cellular response to a biomaterial may be enhanced in synthetic polymer formulations by mimicking the surface roughness created by the associated nano-structured ECM components of natural tissue.