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Radiolabeled Nanoparticles for Cancer Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
Angiogenesis, the formation of new blood vessels can be studied with RNPs. Integrins are expressed on tumor cells as well as actively proliferating endothelial cells that promote tumor cell invasion, angiogenesis that resulting in metastasis [68–72]. Radiolabeled tracers such as 18F-galacto-RGD, 111In-RP747, and 99mTc-NC100692 for SPECT imaging have been reported for detecting αvβ3 integrin expression related to angiogenesis in tumor [73–76]. Integrin αvβ3-targeted 111In-labeled perfluoro-carbon (PFC) NPs were used to detect angiogenesis in tumor tissue in New Zealand white rabbits bearing tumors and at 18 h after injection, and it was observed the mean tumor radioactivity of integrin αvβ3-targeted PFC NP was four-times than those with non-targeted group (control group) [77].
Nanomagnetic Actuation: Controlling Cell Behavior with Magnetic Nanoparticles
Published in Jeffrey N. Anker, O. Thompson Mefford, Biomedical Applications of Magnetic Particles, 2020
The precise methods by which the various cell types monitor and respond to mechanical stimuli are not fully understood. However, the methods by which cells attach and monitor their various extracellular matrices, share numerous commonalities. One such method is by attaching directly to the extracellular matrix via transmembrane glycoproteins known as cell surface integrins. These heterodimeric proteins consist of two distinct subunits known as α and β. There are currently 16α and 9β subunits known to exist, which can combine to form a variety of integrins with distinct binding specificities. The intracellular region of the α chain is physically connected to the cytoskeleton via interaction with talin, vinculin, and α-actinin. It is this connection that enables integrins to transduce mechanical stimuli from the extracellular matrix into the intracellular environment (Burridge et al. 1988).
Cell Biology for Bioprocessing
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
The biological role of ECM is not merely to provide a surface appropriate for cell adhesion, but also to provide cell-surface interactions that are linked to the expression of special cell characteristics and growth control (Panel 2.32, Figure 2.17). Cells of the same type may exhibit very different shape and other cell behavior when cultured on different ECMs. The different responses to different ECMs is mediated by transmembrane cell surface receptors, called integrins, that connect the extracellular ECM to the intracellular cytoskeleton and relay the chemical and physical features of the extracellular microenvironment to intracellular signaling events. The integrins are heterodimers of different α and β chains. Different combinations of α and β chains gives the specificity of binding to different ECM molecules. For example, α5β1 integrin binds to fibronectin, while α6β1 binds to laminin. On the intracellular side, integrin binds mostly to actin filaments with the help of some auxiliary binding proteins. Different cell types express different α and β chains and thus form different integrin complexes with different binding affinities for various ECM components. As a result, different cell types often have different ECM requirements for adhesion, growth, or maintaining their differentiated properties. To establish strong and stable interactions between ECM and the cytoskeleton, multiple cell–matrix junction complexes cluster together to form focal adhesion.
Modelling the role of membrane mechanics in cell adhesion on titanium oxide nanotubes
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Matej Daniel, Kristina Eleršič Filipič, Eva Filová, Tobias Judl, Jaroslav Fojt
It is well accepted that the deformation of the cell membrane, interacting with the attached cytoskeleton, affects cell proliferation and differentiation (Pontes et al. 2013). For cell adhesion, a complex network of transmembrane integrins and cytoplasmic proteins is of the utmost importance (Luo et al. 2018). Extracellular components of integrins attach to the extracellular matrix while their intracellular components are attached to F-actin through adapter proteins (Kanchanawong et al. 2010) and may directly affect cell nucleus shape (Anselme et al. 2018). Park et al. (2007) proposed the hypothesis that the optimal diameter of nanotubes is determined by integrin size. The size of an extracellular domain of integrins is about 10 to 12 nm (Kanchanawong et al. 2010) and thus the close packing of integrins results in their optimal activation. This hypothesis is supported by the measurements showing that the 15–20 nm spacing is optimal for cell adhesion, proliferation, migration, and differentiation (Park et al. 2007, 2009a). This theory was further implemented into the mathematical model of osteoblast adhesion (Gongadze et al. 2013). The model well explains the narrow window of optimal diameter observed by Park et al. (2009a) but fails to explain the stability of larger diameters observed experimentally (Table 1).
Epidemiology, virology and clinical aspects of hantavirus infections: an overview
Published in International Journal of Environmental Health Research, 2022
Sima Singh, Arshid Numan, Dinesh Sharma, Rahul Shukla, Amit Alexander, Gaurav Kumar Jain, Farhan Jalees Ahmad, Prashant Kesharwani
The hantavirus genome synthesis of viral RNAs includes transcription and replication. Transcription helps to produce to produce viral protein-encoding mRNAs and replication to produce viral genomic RNA as shown in Figure 3. The viral RNA-dependent RNA polymerase (RdRp) is responsible for all of these functions (Sironen and Plyusnin 2011). Hantavirus is replicated in macrophages and vascular endothelial cells in patients, especially in the lungs and kidneys (Yanagihara and Silverman 1990). Moreover, thus, cultures of endothelial cells are used for hantavirus infection as in vitro models. The entry of hantaviruses into cells is thought to be mediated by certain host cell surface proteins. The replication cycle starts by attaching pathogens to the receptor of the host cell surface (Markotić et al. 2007). Several findings clearly indicate that the viral Gn protein interacts with integrin receptors on the surface of host cells to mediate binding (Mir and Panganiban 2010). Integrins are a heterodimeric protein family that contain α-chain and β-chain. It promotes cell-cell adhesion as well as cell-extracellular matrix adhesion (Takagi and Springer 2002; Campbell and Humphries 2011).
Bioinks—materials used in printing cells in designed 3D forms
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Dilara Goksu Tamay, Nesrin Hasirci
Gelatin is the denatured, partially hydrolyzed and soluble form of collagen which is present in cartilage, bone and skin of mammalians as the main component of extracellular matrix. The conformation is completely different than the collagen due to the thermal denaturation or disintegration of the hydrolysis process. Due to its biocompatibility, it is widely used in pharmacy and cosmetics. In its structure, there are the biological cues as RGD sequence, which enhances the cell adherence via integrin receptors. This makes gelatin attractive material for making scaffolds for tissue engineering applications [72,102–104] and carriers for bioactive agents used in pharmacy [105–111]. In one study, transglutaminase-crosslinked gelatin 3D printed constructs were prepared and its ability for development of vascularized constructs was searched, so that these constructs may be used as tissue or tumor models [112]. Gelatin can also be coated on different materials to enhance their biocompatibility. It was showed that gelatin immobilized onto porous scaffolds by physical entrapment and chemical crosslinking showed greatly enhanced surface properties on attachment, proliferation, and ECM deposition of osteoblasts, endothelial cells or stem cells [113–116].