Mitochondrial Dysfunction In Neurodegenerative Disorders

As age related diseases increase in prevalence and impact more significantly on medical resources it is imperative to understand these diseases and the mechanisms behind their progression. New research has stimulated a growing interest in mitochondrial involvement in neurodegenerative disorders such as Parkinson’s disease, Alzheimer’s disease and multiple sclerosis and the mechanisms which lead from mitochondrial dysfunction to neurodegeneration. Mitochondrial Dysfunction in Neurodegenerative Disorders brings together contributions from leaders in the field internationally on the various ways in which mitochondrial dysfunction contributes to the pathogenesis of these diseases, guiding the reader through the basic functions of mitochondria and the mechanisms that lead to their dysfunction, to the consequences of this dysfunction on neuronal function before finishing with the modelling of these disorders and discussion of new potential therapeutic targets. Mitochondrial Dysfunction in Neurodegenerative Disorders provides an accessible, authoritative guide to this important area for neurologists; research and clinical neuroscientists; neuropathologists; and residents with an interest in clinical research.

Methods in Toxicology, Volume 2: Mitochondrial Dysfunction provides a source of methods, techniques, and experimental approaches for studying the role of abnormal mitochondrial function in cell injury. The book discusses the methods for the preparation and basic functional assessment of mitochondria from liver, kidney, muscle, and brain; the methods for assessing mitochondrial dysfunction in vivo and in intact organs; and the structural aspects of mitochondrial dysfunction are addressed. The text also describes chemical detoxification and metabolism as well as specific metabolic reactions that are especially important targets or indicators of damage. The methods for measurement of alterations in fatty acid and phospholipid metabolism and for the analysis and manipulation of oxidative injury and antioxidant systems are also considered. The book further tackles additional methods on mitochondrial energetics and transport processes; approaches for assessing impaired function of mitochondria; and genetic and developmental aspects of mitochondrial disease and toxicology. The text also looks into mitochondrial DNA synthesis, covalent binding to mitochondrial DNA, DNA repair, and mitochondrial dysfunction in the context of developing individuals and cellular differentiation. Microbiologists, toxicologists, biochemists, and molecular pharmacologists will find the book invaluable.

Mitochondria have long been the Rodney Dangerfield of cellular organelles. Believed to be the remnants of bacterial infection of eukaryotic cells eons ago, the mitochondrion evolved a symbiotic relationship in which it dutifully served as the efficient source of A TP for cell function. The extraordinary dependence of cells on the energy provided by mito chondrial oxidative metabolism of glucose, especially through critical organs such as the heart and brain, is underlined by the fatal consequences of toxins that interfere with the mitochondrial electron transport system. Consistent with their ancestry, the mitochondria have their own DNA that encodes many but not all of their proteins. The mitochon dria and their genes come from the mother via the ovum since sperm do not possess mitochondria. This extranuclear form of inheritance derived exclusively from the female side has proven to be a powerful tool for tracing the evolution by the number of base substitutions in mtDNA. That mitochondrial gene mutations might be a source of human dis ease became evident a decade ago with the characterization of a group of multisystem disorders, typically involving the nervous system, which are transmitted from mother to child. Specific point mutations in mtDNA have been associated with the different syndromes.

The mitochondrion is a unique and ubiquitous organelle that contains its own genome, encoding essential proteins that are major components of the respiratory chain and energy production system. Mitochondria play a dominant role in the life and function of eukaryotic cells including neurons and glia, as their survival and activity depend upon mitochondrial energy production and supply. Besides energy production, mitochondria also play a vital role in calcium homeostasis and may induce apoptosis by excitotoxicity. Mitochondrial dysfunction is related to common neurological diseases, such as Parkinson's disease, Alzheimer's disease, Friedreich's ataxia, Huntington's disease, and Multiple Sclerosis. An efficient treatment of mitochondrial dysfunction would open new horizons in the therapeutic perspectives of a substantial number of inflammatory and degenerative neurological disorders.

Mitochondria are critical to the survival of cells, therefore, it is not surprising that abnormalities in mitochondrial function may lead to human disease. This book concentrates on the biology and pathology of mitochondria, covering some ot the important basic science features of the biology of mitochondria. It then moves on to discuss the breadth of human diseases related to mitochondrial dysfunction, including Parkinson's disease, Amyotrophic Lateral Sclerosis (ALS), and Alzheimer's disease. * Provides comprehensive coverage of basic science and clinical features of mitochondrial dysfunction * Presents detailed analysis of "hot" topics in mitochondrial function and neurodegenerative diseases * Includes outstanding list of contributing authors

The discovery that several major human neurodegenerative diseases are associated with mitochondrial dysfunction has provided new opportunities for a better understanding of these diseases. In this book, major figures in the field offer state-of-the-art reviews of the role of mitochondrial dysfunction and oxidative damage in the pathogenesis of neurodegenerative diseases. Because many of the topics presented overlap with one another, the result is the most comprehensive review of the subject to date. Mitochondria and Free Radicals in Neurodegenerative Diseases begins with a historical overview of the field presented by one of its distinguished founders. The book goes on to supply detailed information on energy metabolism in normal brain function and to explore the role of oxidative damage—which may be a consequence of mitochondrial dysfunction—in the nervous system. Other early chapters focus on energy dysfunction leading to excitotoxic cell damage, the role of mitochondrial toxins in the pathogenesis of animal models of neurodegenerative diseases, and the role of mitochondria in aging. Additional topics include: Neurologic and neuropathologic consequences of mitochondrial disorders The role of mitochondria and oxidative damage in amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease, Alzheimer's disease, and cerebellar degenerations Using MRI spectroscopy to assess energy defects in patients with neurodegenerative diseases Potential therapies for neurodegenerative diseases The role of glutamate receptor antagonists for therapy Known approaches to improving energy function in mitochondrial disorders Free radical scavengers and other innovative therapeutic approaches Cover image: Three-dimensional reconstruction of an isolated, condensed rat-liver mitochondrion, obtained by electron tomography, courtesy of Dr. Carmen A. Mannella and Wadsworth Center. Reproduced with permission from TiBS (1997) vol. 22, issue 2, pp. 37-38.

Several pathogenic mechanisms are involved in the pathogenesis of Parkinson’s Disease (PD), a neurodegenerative disease characterized by the loss of substantial nigra (SN) dopamine (DA) neurons. Alterations in calcium (Ca2+) homeostasis, cellular proteostasis, axonal transport, mitochondrial function, and neuroinflammation are linked to PD. However, research involving inter-organelle communication and their significance as precise mechanisms underlying neuronal death in PD remain to be elucidated. Evidence showed that perturbations in the mitochondria-endoplasmic reticulum (ER) network play an important role in the pathogenesis of PD. Alterations in the mitochondria-ER interface have been reported in PARK2 knockout mice and patients harboring PARK2 mutations. Enhanced parkin levels maintain mitochondria-ER cross-talk and assure regulated Ca2+ transfer to sustain cell bioenergetics. Several familial PD-related proteins, including Parkin and PINK1, may lead to modifications in the mitochondria-ER signaling. Interestingly, mitochondria-ER tethering suppresses mitophagy and parkin/PINK1-dependent mechanism regulates the destruction of mitochondria-ER contact sites by catalyzing a rapid burst of Mfn2 phospho-ubiquitination to trigger p97-dependent disassembly of Mfn2 complexes from the outer mitochondrial membrane. Mitofusin-mediated ER stress elicited neurodegeneration in Pink1/Parkin models of PD. α-Synuclein, a presynaptic protein, can bind to the ER-mitochondria tethering protein vesicle-associated membrane protein-associated protein B (VAPB) to disrupt Ca2+ homeostasis and mitochondrial ATP production. It has been reported that ER stress and mitochondrial cell death pathways might mediate A53T mutant α-synuclein-induced toxicity. Mitochondria-ER signaling mechanism is poorly characterized in neurons and its association in neuronal pathophysiology remains uncertain. The presence of mitochondria-ER contacts in neurons, preferentially at synapses, suggests a potential role in regulating synaptic activity. Alterations in mitochondria-ER associations are expected to be potentially detrimental to neurons, especially to SN DA neurons. Compounds from an unbiased chemical screen reverse both ER-to-Golgi trafficking defects and associated mitochondrial dysfunction in different PD models. In addition, a dibenzoylmethane derivative protects DA neurons against ER stress. Thus, mitochondria-ER signaling may represent a possible upstream drug target as potential therapeutic strategy for PD. In this Research Topic, we bring together knowledge that emphasizes the importance of mitochondria-ER communication and its impact to further dissect the pathogenic mechanisms in PD.