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Understanding the Interaction of Nanoparticles at the Cellular Interface
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
The dynamics of the interaction of NPs with cells and their organelle explains the process of how the NPs end-up inside lysosomes and endosomes. These play a significant role in regulating the intracellular transport and degradation of foreign bodies. Utilizing NPs as carriers of biomolecules or drugs has found a new dimension into medical requirements with improved technical expertise. NPs, after endocytosis, are transported into early endosomes where most of the sorting occurs. Parallelly, the transport of some NPs moves to recycle endosomes, where finally they are excreted out from the cells. NPs inside the early endosomes move into the cell interior along the microtubules. The transport of cargos from late endosomes to lysosomes is a unidirectional process where late endosomes fuse with lysosomal bodies [55]. There are approximately 50−1000 lysosomes of sizes ranging from as small as 0.1 µm to as large as 1.5 µm in a cell. The size and number of lysosomes vary widely based on the environmental cue, type of cell, and disease conditions [56]. The primary function of lysosome is to hydrolyze any biomolecule that comes into it, implying the presence of hydrolases inside the lumen of the organelle. Its lumen also contains various enzyme activators, transport proteins (NPC2), and other protective factors with an acidic pH of 4.5−5.0 maintained with the help of vacuolar ATPase [57].
Cell Biology for Bioprocessing
Published in Wei-Shou Hu, Cell Culture Bioprocess Engineering, 2020
Lysosomes are small organelles where the degradation of many cellular materials takes place. Its lumen is a low pH environment (pH ~4.5) and it contains many enzymes that hydrolyze proteins, nucleic acids, and lipids (Panel 2.13). It has proton pumps in the membrane to maintain a low interior pH. It is the site of degradation of both ingested materials and cellular materials that are no longer needed by the cell. Most cellular materials have a finite life span, regardless of whether they are catalyzing chemical reactions or playing structural or mechanical roles. Over time, any cellular material can be oxidized or chemically modified in other ways in some part of its structure. The accumulation of such “damages” may render a protein non-functional. Thus, most proteins and other cellular materials, such as RNAs and lipids, are turned over after a finite period of time. Many of such processes occur in lysosomes. For some proteins, this occurs in proteasomes. Proteasomes are complexes of proteolytic enzymes that are capable of degrading proteins. Proteins that need to be turned over are tagged by ubiquitin and sent to the proteasome for degradation. Lysosomes are not trash cans, but rather more like recycling centers. They play an important role in lipid homeostasis. Lipids taken up from the extracellular environment and other organelles are processed and then redistributed to maintain the proper lipid composition in the membranes of different organelles.
Outdoor Air Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
The lysosomal degradation pathway of autophagy is known as a self-digestion process by which cells not only get rid of misfolded proteins, damaged organelles, and infectious microorganisms, but also provide nutrients during fasting. Of course, fasting is essential in chemical sensitivity and is used frequently to clear pain, lack of energy, and brain dysfunction. The defect of this process has found an emerging role in many human diseases such as cancer, neurodegeneration, diabetes, aging, and disorders of the liver, muscle, and heart.193–195 There are a few reports on the involvement of defective autophagy in toxic effects of pesticides. A relationship between autophagy and paraquat-induced apoptosis in neuroblastoma cells was shown by Gonzalez-Polo and colleagues in 2007.196 This effect was confirmed in another study in which paraquat-induced autophagy was attributed to the occurrence of ER stress.197 Lindane, a broad-spectrum organochlorine pesticide, has been reported to promote its toxicity through the disruption of an autophagic process in primary rat hepatocytes.198 All of these substances have been shown to trigger chemical sensitivity.
Apigenin attenuates tetrabromobisphenol A-induced cytotoxicity in neuronal SK-N-MC cells
Published in Journal of Environmental Science and Health, Part A, 2023
Eun Mi Choi, So Young Park, Kwang Sik Suh, Suk Chon
Autophagy involves the delivery of large protein aggregates, defective organelles, and other cellular debris to lysosomes for degradation and recycling. Generally, autophagy promotes the self-renewal of organisms, which helps recycling of materials and facilitates cell survival in adverse environments.[38,39] On the other hand, excessive autophagy causes structural damage to cellular components, leading to cell senescence or death.[40] Autophagy was upregulated in the brain of AD patients but downregulated in normal aging cohorts, indicating that autophagy protects brain cells from aging in the physiological process but acts as a death mechanism when overactivated in the pathologic event.[41,42] We observed TBBPA-induced cytotoxic, but not pro-survival, autophagy, leading to death of SK-N-MC cells, suggesting that inhibition of autophagy may contribute to the survival of neurons. Moreover, apigenin partially reversed TBBPA‐induced neuronal death through the attenuation of autophagy. Taken together, our data suggest that apigenin has neuroprotective potential against TBBPA through the inhibition of autophagy, apoptosis, and necrosis.
Accumulation, subcellular distribution, and ecological risk assessment of Pb and Cd in Bellamya aeruginosa from the Xiangjiang River, China
Published in Chemistry and Ecology, 2020
Jun Liu, Wei Huang, Zhiliang Li, Jingsong Hu, Yunhua Zhu, Hongyan Xie, Cuiying Peng
Lysosomes are ‘digestive organs’ in cells, which contain acidic hydrolases and can degrade and remove hazardous substances effectively. Studies have shown that lysosomes release hydrolase after interaction with Cd [48], Cd binds with enzyme proteins to form a Cd complex and the thiol groups of the lysosomal enzyme chelate with Cd, making it ‘inactive’, thereby alleviating the toxic effect of Cd on cells [49]. channels on the surface of mitochondria, Cd binds to proteins associated with calcium, causing increased permeability of mitochondrial membranes [50], passes through the pore into the mitochondria, binds to the sulfhydryl group of the electron-transporting complex on the inner membrane, and enhances mitochondrial respiratory activity [51]. Cd has a high affinity for sulfhydryl groups and can chelate thiol-containing proteins such as metallothionein and glutathione, which are abundant in the mitochondrial membranes and their matrix [52]. Chelated Cd is in an ‘inactive’ state, thereby alleviating its toxic effects on cells. Lysosomes and mitochondria are important target sites and accumulation sites for Cd in B. aeruginosa, the Cd accumulation of which was much higher than that in other subcellular components. This showed that the cell membrane of the foot and visceral mass is highly permeable to Cd, causing a large proportion of Cd to influx into the interior of cells and was mainly distributed in lysosome and mitochondrial components, whereas Cd was rarely enriched in the nuclei, cell membrane, and microsomes. This subcellular distribution of Cd in B. aeruginosa is a detoxification mechanism to reduce the damage of Cd to the ‘genetic control centre’-nucleus.
Exenatide promotes the autophagic function in the diabetic hippocampus: a review
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Eman Mohammed Elsaeed, Ahmed Gamal Abdelghafour Hamad, Omnia S. Erfan, Mona A. El-Shahat, Fathy Abd Elghany Ebrahim
The degradation of cellular components can be achieved by two major systems: the ubiquitin-proteasome system and autophagy. The ubiquitin-proteasome system is concerned with the degradation of the short-lived proteins, as they are tagged by ubiquitin, and recognized and degraded by the proteasome. Autophagy is the process by which eukaryotic cells get rid of intracellular organelles and protein aggregates that cannot be degraded by the proteasome. It degrades long-lived proteins, lipids, and cytoplasmic organelles via a lysosome-driven process [15, 16]. It occurs at a basal level in all cells, and it helps maintain cellular homeostasis. Also, it is proven to have a role in development and disease [17].