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Cartilage Mechanobiology
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Hai Yao, Yongren Wu, Xin L. Lu
Mechanical loading can cause robust fluctuation of intracellular calcium concentration by activating PLC and IP3 pathway [172,194] through IL-4 [183]. As one of the earliest intracellular responses in chondrocytes under mechanical stimulation, calcium signaling can initiate or regulate the secretion of growth factors and cytokines. The released autocrine or paracrine factors may bind to transmembrane receptors, such as G-protein coupled receptors (GPCR), to further initiate MAPK, PKC, and NF-kB pathways. Additionally, it can activate calmodulin kinase, resulting in the activation of transcription factor AP-1. It has been shown that aggrecan gene expression and electrophysiological response were suppressed under cyclic loading (0.33 Hz, 20 min) when the calmodulin pathway was inhibited [172]. Cyclic AMP (cAMP), another important second messenger for PG synthesis, can also cross-talk with calcium signaling [119]. It has been shown that gene expressions of bovine cartilage explants were regulated by cAMP through PKA pathway under static compression [95].
Functional Properties of Muscle
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Ca2+ bind to the protein calmodulin (Section 6.3.1), which activates the enzyme myosin light chain kinase (MLCK). This enzyme phosphorylates the myosin light chain in the myosin head, in the presence of ATP. Only when the myosin head is phosphorylated can it combine with actin to form cross bridges and initiate cross-bridge recycling through ATP splitting. To relax the muscle, the myosin is dephosphorylated by the enzyme myosin light chain phosphatase, which is continuously active in smooth muscle. However, when the concentration of Ca2+ rises, the rate of phosphorylation exceeds that of dephosphorylation and cross-bridge recycling occurs. The converse applies when the concentration of Ca2+ falls.
Implications of CRISPR Technology in Biological Systems
Published in Jyoti Ranjan Rout, Rout George Kerry, Abinash Dutta, Biotechnological Advances for Microbiology, Molecular Biology, and Nanotechnology, 2022
Kikku Sharma, Souvik Sen Gupta
Cardiovascular diseases constitute a major and increasing health problem in today’s world. There are many challenges to gain deeper knowledge about the common and less common causes of cardiovascular mortality. Genetic testing and bioinformatic analyzes have helped to identify the susceptibility of subjects to particular cardiac diseases like coronary and peripheral artery disease (CAD and PAD), rheumatic, hypertensive and congenital heart disease, cerebrovascular disease (stroke), and arrhythmias. The innovative discovery of induced pluripotent stem cells revolutionized the field of genome editing and now the iPS cells are widely used in cardiomyogenesis. iPS cells derived from cardiomyocytes (CM) are used as a unique tool in the field, wherein several scientists have made efforts toward satisfactory in vitro maturation of iPS cells to generate a better model for cardiac pathologies. The iPS cell has many potential functions. For example, if an individual is affected with long QT interval then the iPS cells from this individual may be induced to generate functional CM, which may address the problem. In the case of individuals with structural cardiac defects such as dilated cardio-myopathy (DCM) and hypertrophic cardiomyopathy (HCM), the iPS cells show mutations. The iPS cells derived from DCM show a mutation in a gene that encodes for troponin which leads to abnormality in Ca2+ handling and also abnormal arrangement of sarcomeric actin that leads to a decrease in the contractility of the heart. A single missense mutation in the MYH7 gene of the iPS cells derived from HCM patients show unorganized sarcomere and decreased electrophysiological polarity that leads to serious problems. The CRISPR-CAS9 system has been experimentally used for gene knockin and knockout in human iPS cells. So this technology may be used to correct the genetic mutations in the iPS cell model. Barth syndrome is an X-linked genetic cardiac disease that may be eradicated by the combination of iPS cells and CAS9-mediated genome editing. Mutation in the tafazzin (TAZ) gene of iPS cells of a healthy donor by CAS9-mediated genome editing tools have helped to identify the relationship between TAZ gene mutations that cause the disease and mitochondrial phenotypes. The titin gene mutations in DCM have also been evaluated by the CRISPR-CAS9 system (Motta et al., 2017). The CRISPR-CAS9 system can also edit genes of somatic cells in vivo. It can disrupt the proprotein convertase subtilisin/Kexin type 9 (PCSK9) gene, which leads to the lowering of blood cholesterol resulting in the lowering of coronary heart disease. By rectifying the mutation in the calmodulin gene of iPS cells, we can overcome the problem of long QT syndrome. Long QT-associated calmodulin inactivation occurs due to the mutation in CALM1, CALM2 and CALM 3 gene. The long QT syndrome is mediated by the mutation in six calmodulin producing alleles and CRISPR interference technology can selectively rectify these mutated alleles. In this technique, the dCas9 and its associated g RNA bind to the promoter and inactivate RNA polymerase leading to transcriptional deactivation of the mutant alleles.
Lead alters intracellular protein signaling and suppresses pro-inflammatory activation in TLR4 and IFNR-stimulated murine RAW 264.7 cells, in vitro
Published in Journal of Toxicology and Environmental Health, Part A, 2019
R.J. Williams, E. Karpuzoglu, H. Connell, D.J. Hurley, S.D Holladay, R.M. Gogal
Lead is a divalent cation that has no known beneficial biological function in any organism, yet upon entry, displays the ability to compete with essential divalent cations for cellular binding sites in the body. Previously, Kirberger and Yang (2008) and Kirberger et al. (2013) demonstrated that Pb competed with calcium and bind calmodulin at the 4 EF calcium-binding sites and through opportunistic binding along the central helix of the protein. Calmodulin is a ubiquitously expressed protein located in the cytoplasm of cells that selectively binds calcium. Once calcium binding occurs, calmodulin activates downstream proteins in the cascade including kinases, which further relay the cellular signal (Soderling 1999). One class of proteins that is a target for calmodulin is the calcium/calmodulin-dependent protein kinases (CaMK) (Wayman et al. 2011). Proteins within this class include CaMKK, CaMKI, CaMKIV, and CaMKII, which are involved in the regulation of a vast array of cellular functions (Wayman et al. 2011). Binding of Pb to calmodulin induces conformational changes in the protein, which exhibits the potential to inhibit activation of downstream kinases and thus limit responses to cellular stimuli (Kirberger et al. 2013).
A generalized study of the distribution of buffer over calcium on a fractional dimension
Published in Applied Mathematics in Science and Engineering, 2023
Sanjay Bhatter, Kamlesh Jangid, Shyamsunder Kumawat, Sunil Dutt Purohit, Dumitru Baleanu, D. L. Suthar
In this paper, we have discussed four buffers (EGTA, Troponine, Calmodulin, BAPTA). BAPTA primarily protects cells against toxic calcium overload. EGTA is a chelating agent with a high affinity for calcium ions. EGTA is used as a buffer equal to the pH of the living cell. Calmodulin is a critical neuronal protein that is a crucial mediator of several -dependent intracellular signalling cascades in the brain. Calmodulin modulates synaptic transmission and synaptic plasticity through Ca, which relies on its target proteins in pre and postsynaptic compartments. Calmodulin is a regulatory protein used to detect changes in calcium ion concentration.
A novel colorimetric assay for calcium ion and calmodulin detection based on gold nanoparticles
Published in Inorganic and Nano-Metal Chemistry, 2020
Calmodulin, as a cellular Ca2+ -binding protein, consists of two globular domains at C- and N-terminus, and each contains two canonical EF hands as Ca2+-binding motifs.[9] Calmodulin can mediate a series of intracellular signaling transductions by binding to Ca2+, playing a key role in the human body.[10] Consequently, the development of facile and reliable for Ca2+ and calmodulin detection is essential in life science study.