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Active Nanoparticle Targeting: Current Status and Future Challenges
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Siddharth Patel, Janni Mirosevich
The ER, Golgi apparatus, and peroxisome subcellular compartments have received attention for organelle-targeted therapeutics because of their role in various diseases (Mossalam, Dixon, and Lim 2010). Protein folding primarily occurs at the ER (Kleizen and Braakman 2004). Proteins are then transported to the Golgi apparatus where they are further modified and packaged for intracellular distribution or excretion into the extracellular space (Hong 1998). pH-sensitive imino-sugar containing liposomes and ER-targeted PLGA nanoparticles, containing antigenic peptides and fluorescent markers, have been shown to target the ER and the Golgi apparatus (Costin et al. 2002; Sneh-Edri, Likhtenshtein, and Stepensky 2011). Peroxisomes are involved in various metabolic and biochemical pathways in eukaryotic cells and contain many different enzymes responsible for catalyzing reactions, including the breakdown of fatty acids, amino acids, and uric acid, and plasmalogen biosynthesis (Terlecky and Koepke 2007; Bonekamp et al. 2009). Damage to proteins inside peroxisomes can disrupt peroxisomal function, causing several serious diseases. Peroxisomal targeting signal peptide was originally recognized to direct cytoplasmic proteins delivery to peroxisomes (Gould, Keller, and Subramani 1987). This initial discovery led to the development of another peroxisome therapeutic for human hypocatalasemic fibroblasts using SKL (serine-lysine-leucine) peptide (a peroxisomal targeting sequence)-tagged catalase (Terlecky and Koepke 2007).
General Introductory Topics
Published in Vadim Backman, Adam Wax, Hao F. Zhang, A Laboratory Manual in Biophotonics, 2018
Vadim Backman, Adam Wax, Hao F. Zhang
Lysosomes are the main centers of catabolism. Old organelles are delivered to the lysosomes for degradation. Lysosomes are filled with acid hydrolases (about 40 different enzymes) such as proteases (for protein degradation), nucleases, lipases (digestion of lipids), etc. Proteasomes are large protein complexes. Each proteasome is a cylinder-like structure composed of several different proteases. These are responsible for degradation of misfolded proteins. The latter are tagged by protein ubiquitin and fed to a proteasome. The role of peroxisomes is β-oxidation of fatty acids. Much like mitochondria, peroxisomes are self-replicating. The main difference is that peroxisomes lack their own DNA and ribosomes and depend entirely on the availability of proteins free-floating in the cytosol.
Bioenergy Principles and Applications
Published in Eduardo Rincón-Mejía, Alejandro de las Heras, Sustainable Energy Technologies, 2017
Marina Islas-Espinoza, Alejandro de las Heras
Striking examples of hybridization are given by chloroplasts, mitochondria, and peroxisomes, reckoned to have a bacterial origin. Chloroplasts are responsible for photosynthesis. The transformation of solar to chemical energy occurs in the reaction center, where the absorbed excitation energy is converted into a stable charge-separated state by ultrafast electron transfer events (Romero et al., 2014). Mitochondrial oxidation is associated with the respiratory chain and the tricarboxylic cycle that leads to the production of ATP, while peroxisomal metabolism is associated with mechanisms of detoxification and the biosynthesis of specific fatty acids. Peroxisomes cooperate with mitochondria in lipid metabolism, oxidizing fatty acids, and in reactive oxygen species production (Demarquoy and Le Borgne, 2015).
Metabolomics profiling of valproic acid-induced symptoms resembling autism spectrum disorders using 1H NMR spectral analysis in rat model
Published in Journal of Toxicology and Environmental Health, Part A, 2022
Hyang Yeon Kim, Yong-Jae Lee, Sun Jae Kim, Jung Dae Lee, Suhkmann Kim, Mee Jung Ko, Ji-Woon Kim, Chan Young Shin, Kyu-Bong Kim
3-Hydroxyisovalerate and pimelate belong to a class of organic acids and short-chain fatty acids. There is a case study of a child with autism that showed long-chain acyl-CoA dehydrogenase deficiency (Clark-Taylor and Clark-Taylor 2004). Fatty acid β-oxidation is the major pathway to produce ATP and reducing power from different chain lengths of fatty acids, which are activated in the mitochondria and peroxisomes. The first reaction of mitochondrial fatty acid β-oxidation (FAO) in the mitochondria is catalyzed by acyl‐CoA dehydrogenase. With long-chain acyl-CoA dehydrogenase deficiency, the VPA-induced group might contain decreased levels of short-chain fatty acids in urine. In addition, when mitochondrial dysfunction occurs, β-oxidation of polyunsaturated fatty acids is diverted to the peroxisome, leading to generation of FADH2 by β-oxidation and production of hydrogen peroxide (H2O2) rather than energy in the peroxisome. Hydrogen peroxide induces oxidative stress in cells, and evidence suggested a relationship between oxidative stress and autism (Chauhan and Chauhan 2006; Rossignol and Frye 2014). Therefore, data suggested that urinary metabolites such as galactose, galactonate, 3-hydroxyisovalerate, valerate and pimelate might serve as significant biomarkers of VPA-induced effects resembling ASD.
Microbial valorization of waste cooking oils for valuable compounds production – a review
Published in Critical Reviews in Environmental Science and Technology, 2020
Marlene Lopes, Sílvia M. Miranda, Isabel Belo
Some filamentous fungi and yeast species were also reported as capable of growing on oily substrates, since these microorganisms are able to (a) synthetize biosurfactants for lipids solubilization, (b) modify the cell surface to enable the adhesion of lipids and (c) secrete extracellular lipases that hydrolyze the triglycerides into glycerol and fatty acids. Particularly in yeasts, fatty acids droplets bind onto the protrusions formed in the cell surface and enter into the cytosol. Here, fatty acids degradation is finalized through the β-oxidation pathway in the peroxisomes, by the interaction between the glyoxylate cycle (peroxisome) and citrate cycle (mitochondrion) or stored in lipid bodies as TAGs and steryl esters (SE). Lipids accumulated intracellularly in lipid bodies could be also mobilized by intracellular lipases, encoded by the TGL genes, to the peroxisome to carry out the β-oxidation (Beopoulos, Chardot, & Nicaud, 2009; Fickers et al., 2005).
Genetic polymorphisms of PPAR genes and human cancers: evidence for gene–environment interactions
Published in Journal of Environmental Science and Health, Part C, 2019
Peroxisomes are single membrane-bound organelles, with a granular matrix, that are found in different types of animal and plant cells. Peroxisomes host diverse metabolic functions, including α- and β-oxidation of fatty acids, bile acid and phospholipid biosynthesis, cholesterol biotransformation, and detoxification of oxygen-based reactive metabolites.1 Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear transcription factors that acquired their name when the first discovered receptor in this group was shown to mediate peroxisome proliferation in rodents upon chemical exposure. PPARs are currently associated with a much wider range of systemic and cellular functions beyond their reported role when first discovered (Figure 1). These receptors mainly regulate cellular functions and gene expression based on an activation by a ligand. Following binding by an agonist, PPARs release histone deacetylase (HDAC) co-repressors, hence enabling their hetero-dimerization with the retinoid X receptor (RXR). The RNA Polymerase II and the rest of the transcription machinery are then recruited to the forming complex in order to bind to PPAR responsive regulatory elements, known as direct repeat elements.2,3 This mechanism underlies PPARs’ involvement in the transcription of target genes that contribute to metabolism of hormones, carbohydrates, various lipids and general adipogenesis, as well as inflammatory responses, cell death, cell proliferation, and oncogenic signaling.3 Whether a PPAR functions as an oncogene or as a tumor suppressor gene is still uncertain. This is mainly due to the complexity of the pathways that are regulated by PPARs, and their tendency to be altered in tumorigenesis in various types of cancer. The fact that PPARs are activated by both endogenous ligands and xenobiotics underlies their potential ability to regulate tumorigenesis dependently or independently of an environmental exposure.4 In addition, their role in cancer-associated biological processes, including apoptosis, cell proliferation, and terminal differentiation, is still under research, with controversial results showing in many published reports.3 Similarly, several studies and systematic reviews investigating an association between PPARs’ polymorphisms and cancer risk are also showing inconsistencies.5–7 However, data on gene–environment interactions potentially underlying these associations remains largely unexamined despite the fact that some studies have suggested PPARs as important factors at the interface between genes and the environment.8 This review aims at comprehensively examining the existing evidence of gene–environment interaction (GxE) underlying PPARs genetic polymorphisms and their association with cancer risk.