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Mitochondria and Embryo Viability
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Irene Corachan Garcia, Laura Iñiguez Quiles, Antonio Diez-Juan
Mitochondria play a critical role in the generation of metabolic energy in eukaryotic cells, using oxidative phosphorylation to derive energy (ATP) from carbohydrates and fatty acids. Mitochondria contain their own DNA, which encodes tRNAs, rRNAs, and some mitochondrial proteins (1). Ranging in size from 0.5 to 1.0 μm in diameter (2), these unique organelles have a double-membrane system consisting of inner and outer membranes separated by an intermembrane space (1). The outer mitochondrial membrane encloses the matrix (internal space) and contains a large number of proteins that form channels allowing small molecules to pass. The inner mitochondrial membrane, which is folded into structures (cristae) that increase the surface area, is less permeable, blocking the movement of ions and other small molecules. Both the inner and outer membranes contain specific transport proteins that can move molecules by a passive or active transport (2) (Figure 15.1).
Exercise Training, Mitochondrial Adaptations, and Aging
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Nashwa Cheema, Matthew Triolo, David A. Hood
Mitochondria not only produce energy but also play an integral part in intracellular calcium regulation, the regulation of the membrane potential, steroid synthesis, hormone signalling, and apoptosis. Mitochondria have an important role in the intrinsic pathway of apoptosis, as the intermembrane space houses many proteins that are integral in initiating apoptosis. Once a cell death stimulus is received, apoptotic factors in the cytosol translocate to the mitochondria and permeabilize the outer mitochondrial membrane. Cytochrome c is released into the cytosol which cleaves procaspase 9, thus activating its caspase activity. A subsequent caspase cascade is initiated, which results in DNA fragmentation, the formation of apoptotic bodies, and ultimately cell death.
Genetic Disorders of the Autonomic Nervous System
Published in David Robertson, Italo Biaggioni, Disorders of the Autonomic Nervous System, 2019
Monoamine oxidase (MAO) (EC1.4.3.4) is a flavin-containing enzyme involved in the breakdown of a number of biogenic amines, including noradrenaline, dopamine and serotonin (Murphy, 1978). It is located in the outer mitochondrial membrane of most cell types throughout the body. Of the two forms of the enzyme, monoamine oxidase A (MAOA) was originally defined by its sensitivity to inhibition by low concentrations of clorgyline (Johnston, 1968) and monoamine oxidase Β (MAOB) by its sensitivity to inhibition by low concentrations of selegiline (Knoll and Magyar, 1972). MAOA selectively deaminates noradrenaline and serotonin, while MAOB selectively deaminates phenylethylamine and benzylamine (Garrick and Murphy, 1982). MAOA is often localized in association with catecholamine neurons, while MAOB is often associated with serotonin-containing neurons (Thorpe etal., 1987).
Apoptosis is involved in paraoxon-induced histological changes in rat cerebellum
Published in Drug and Chemical Toxicology, 2022
Zohreh Zare, Sam Zarbakhsh, Shamim Mashhadban, Afshin Moradgholi, Moslem Mohammadi
Apoptosis can be initiated through activation of intrinsic (mitochondrial), extrinsic (death receptor), and perforin/granzyme pathways. The B-cell lymphoma-2 (Bcl-2) family of proteins plays a central role in the regulation of the apoptosis process. These proteins control mitochondrial membrane permeability and can be either pro-apoptotic (e.g., Bax and Bad) or anti-apoptotic (e.g., Bcl-2 and Bcl-x). Pro-apoptotic proteins cause perturbation of the outer mitochondrial membrane and subsequent release of cytochrome c into the cytoplasm, while anti-apoptotic proteins inhibit cytochrome c release. The release of cytochrome c into the cytosol triggers activation of caspase-9 and caspase-3. Caspases are a family of cysteine proteases that cleave proteins at aspartic acid residues after activation and finally lead to cell death (Elmore 2007, Slotkin and Seidler 2012).
RIP1 Regulates Mitochondrial Fission during Skeletal Muscle Ischemia Reperfusion Injury
Published in Journal of Investigative Surgery, 2022
Yu Cao, Shunli Chen, Xiangqing Xiong, Lina Lin, Wantie Wang, Liangrong Wang
As is well-known, mitochondria are incredibly dynamic organelles that regulate multiple metabolic functions, meanwhile they have a great impact on the pathogenesis of various diseases when mitochondrial dynamic is out of balance in response to various stimuli [1]. Excessive mitochondrial fission causes increased mitochondrial fragmentation, impaired energy metabolism and elevated reactive oxygen species (ROS) production, contributing to ischemia reperfusion (IR) injury [2–4]. Dynamin related protein 1 (Drp1) is a large cytosolic GTPase that can be recruited to the mitochondrial outer membrane after being post-translationally modified, which is widely recognized to initiate mitochondrial fission by interacting with outer mitochondrial membrane receptors, and inhibiting Drp1’s activity with Mdivi-1 is able to prevent heart and brain from IR injury in cellular and animal models [3, 4]. The mitochondria are important and essential organelles in the skeletal muscle that closely related to muscle contractibility and plasticity, but the role of Drp1-mediated mitochondrial fission in skeletal muscle IR injury is currently unknown.
Targeting mitochondria in dermatological therapy: beyond oxidative damage and skin aging
Published in Expert Opinion on Therapeutic Targets, 2022
Tongyu C Wikramanayake, Jérémy Chéret, Alec Sevilla, Mark Birch-Machin, Ralf Paus
Before going into details, it may be useful to recapitulate some essentials of mitochondrial biology. Reminiscent of their endosymbiont past, mitochondria are surrounded by two phospholipidic membranes, the outer mitochondrial membrane (OMM) and the inner mitochondrial membrane (IMM), which divide the organelle into two compartments, the matrix and the intermembrane space (IMS) [212] (see Figure 2 for details). Mitochondria contain their own DNA (mtDNA) and translation system. The location of mtDNA in the matrix, in close proximity to the ETC, a major source of reactive oxygen species (ROS), makes it particularly vulnerable to oxidation, resulting in mtDNA mutations that could contribute to the pathogenesis of cancer, diabetes and aging [213]. Mutations in mtDNA are functionally recessive – a biochemical phenotype is only observed when the levels of mutated mtDNA reach a critical threshold, and the proportion of mutated versus wild-type mtDNA has a strong impact on the severity of the pathological phenotypes. Coenzyme Q (CoQ10), a ROS scavenger, and mitochondrial sirtuins (SIRT3 and SIRT4) have been implicated in maintaining mitochondrial health [109,214].