Explore chapters and articles related to this topic
An Outbreak of Oxidative Stress in Pathogenesis of Alzheimer's Disease
Published in Suvardhan Kanchi, Rajasekhar Chokkareddy, Mashallah Rezakazemi, Smart Nanodevices for Point-of-Care Applications, 2022
Sourbh Suren Garg, Poojith Nuthalapati, Sruchi Devi, Atulika Sharma, Debasis Sahu, Jeena Gupta
Cholesterol is a sterol having a molecular formula of C17H62O23 and, present in the cell membranes [32]. The abundance of cholesterols in microdomains of cell membranes is called lipid raft [33]. The binding of APP with these rafts commands the β-secretase to insert APP in a monolayer of phospholipids which accumulate the Aβ1–42 peptides through a mechanism called the amyloidogenic pathway [34]. The mechanism of propagation of Aβ is favored by esterified cholesterols. The elimination of excess cholesterols in the brain can be achieved by an oxidation reaction. Oxysterols are liberated as an end product of oxidation. The oxidation of cholesterols is helpful to prevent their accumulation in the brain. Cholesterol is the major component of the brain. The biochemical event of cholesterol 24-hydroxylase lays the formation of 24-hydroxycholesterol, which has the potential to cross the blood-brain barrier [35]. The brain is the major site for their formation. In astrocytes, the liver-X-receptor controlled pathway is responsible for mediating the efflux of apoE cholesterols. Together, oxysterol and efflux of apoE upregulate the cholesterol homeostasis in the brain which directly links with the progression of AD [36].
Molecular and Cellular Pathogenesis of Systemic Lupus Erythematosus
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
George C. Tsokos, Yuang-Taung Juang, Christos G. Tsokos, Madhusoodana P. Nambiar
The T cell receptor ζ chain associated with the detergent-insoluble fraction is distributed between cytoskeleton as well as lipid-rich membrane microdomains, composed primarily of sphingolipids and cholesterol, and an enriched subset of proteins that float laterally as ‘rafts’ within the plasma membrane.38 Lipid rafts are preformed functional modules that serve as platforms for signal transduction and membrane trafficking. Recent data indicate that lipid rafts are crucial for effecting T cell receptor signal transduction.39,40 T cell receptor engagement leads to translocation and concentration of tyrosine phosphorylated T cell receptor ζ chain and downstream signal transduction molecules within lipid rafts.41 Conversely, perturbation of the structural integrity of lipid rafts inhibits T cell receptor-induced protein tyrosine phosphorylation and calcium flux.40,42
Fluorescence Spectroscopy Enhancement on Photonic Nanoantennas
Published in Marc Lamy de la Chapelle, Nordin Felidj, Plasmonics in Chemistry and Biology, 2019
Recent progress in cell biology indicates that the cell membrane features transient and fluctuating nanoscale assemblies of sterol and sphingolipids known as lipid rafts (Sezgin, 2017). Investigating the role and formation of these nanodomains is of key interest for cell biology. However, the nanometer and microsecond resolutions that are simultaneously required fall far beyond the reach of standard microscopes (Eggeling, 2009). With their ability to confine light into nanometer dimensions and drastically improve the fluorescence signal from a single molecule, optical nanoantennas offer a promising approach to investigate the nanoscale dynamic organization of living cell membranes (Lohmüller, 2012; Flynn, 2017; Pradhan, 2016; Winkler, 2017; Regmi, 2017). The flat geometry of the lipid bilayer membrane is remarkably well suited for the investigation by planar nanoantenna designs. Demonstrations on model lipid membranes (Winkler, 2017) and CHO cell membranes (Regmi, 2017) highlight the potential of nanoantennas to reveal nanodomains of 10 nm dimensions and sub-millisecond characteristic times. This fully biocompatible approach opens interesting opportunities for living cell biophysics with single-molecule sensitivity at ultrahigh spatial and temporal resolutions.
Recent advances in multifunctional dendrimer-based nanoprobes for breast cancer theranostics
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Prashant Kesharwani, Rahul Chadar, Rahul Shukla, Gaurav K. Jain, Geeta Aggarwal, Mohammed A.S. Abourehab, Amirhossein Sahebkar
There are several risk factors associated with the development of BC including personal and family history, breast tissue density, diet and specific exposures. Consumption of fatty diet is a highly focused risk factor of BC pathophysiology [60]. In a cohort study, it was demonstrated that dietary consumption of cholesterol resulted in a strong breast cancer risk [61]. Recently in the MMTV-PyMT mouse model, the impact of elevated cholesterol on breast tumor pathogenesis was evaluated [62]. It was found that a diet rich in cholesterol and normal in fat content significantly reduces tumor latency and enhances tumor growth which implied that cholesterol itself can play important role in tumor pathophysiology. Cholesterol affects tumor pathophysiology by enhancing lipid raft formation and membrane signaling in the BC cells. It was found that cholesterol metabolite 27 hydroxycholesterol (27HC), functions as an active signaling molecule of endogenous ER modulator and as liver X receptor (LXR) agonist. While 27HC enhances tumor growth by acting on the estrogen receptor of BC cells and on LXR, it also acts by initiating epithelial to mesenchymal transition and metastasis [63, 64]. It was established through several reports, that 27HC level gets increased in breast tumor biopsies compared to a normal breast cell and this strongly evidenced that 27HC plays a significant role in BC pathophysiology [65]. Additionally, hereditary mechanisms also account for a 10-15% portion of BC cases and is mostly associated with genetic mutation inheritance of BRCA1 or BRCA2 genes [66]. Pathophysiological features of tumors can potentially influence the choice for treatment and even probable results or prognosis. Tumor tissues can be assessed for such features through histology, immunohistochemistry, fluorescent in situ hybridization, molecular and genetic profiling [67].