Mitochondria In Pathogenesis

Mitochondria are organelles in each cell outside the nucleus and are the energy source of all cells. As such, they are crucial to the healthy functioning of cells. Recent research has shown that mitochondrial dysfunction underlies a broad spectrum of disease, from maternally inherited genetic disorders to metabolism defects, aging, stroke, and neurodegenerative diseases such as Parkinson's, Alzheimer's, and Lou Gehrig's disease. This book brings together top researchers whose work in examining the pathophysiologic processes will lead to new strategies for prevention and treatment.

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.

The concept of mitochondrial diseases originated in 1962 with the description by Luft and coworkers of a patient with nonthyroidal hypermetabolism due to loose coupling of oxidation and phosphorylation in muscle mitochondria. Over the following quarter of a century, thanks to W. King Engel's "ragged-red fibres" as convenient markers for mitochondrial pathology, numerous papers described clinical, morphological, and biochemical features of "mitochondrial myopathies." In 1988 the discovery of mutations in mitochondrial DNA led to an explosive expansion of research into mitochondrial disorders. Throughout the 1990s the rapid identification of multiple mitochondrial gene defects associated with clinically diverse disorders has left practitioners puzzled about diagnosing such heterogeneous and complex syndromes. Through updated data, this book discusses now what Luft aptly called "mitochondrial medicine." In so doing, it considers the pivotal role of mitochondria in drug sensitivity, their key roles in ageing, apoptosis, and neurodegeneration along with primary mitochondrial diseases due to mutations in the nuclear genome, in the mitochondrial genome, or in the cross-talk between the two genomes.

Mitochondria are subcellular organelles evolved by the endosymbiosis of bacteria with eukaryotic cells. They are the main source of ATP in the cell and engaged in other aspects of cell metabolism and cell function, including the regulation of ion homeostasis, cell growth, redox status, and cell signaling. Due to their central role in cell life and death, mitochondria are also involved in the pathogenesis and progression of human diseases/conditions, including neurodegenerative and cardiovascular disorders, cancer, diabetes, inflammation, and aging. However, despite the increasing number of studies, precise mechanisms whereby mitochondria are involved in the regulation of basic physiological functions, as well as their role in the cell under pathophysiological conditions, remain unknown. A lack of in-depth knowledge of the regulatory mechanisms of mitochondrial metabolism and function, as well as interplay between the factors that transform the organelle from its role in pro-survival to pro-death, have hindered the development of new mitochondria-targeted pharmacological and conditional approaches for the treatment of human diseases. This book highlights the latest achievements in elucidating the role of mitochondria under physiological conditions, in various cell/animal models of human diseases, and in patients.

Mitochondrial Metabolism: An Approach for Disease Management covers mitotherapy from three combined perspectives, Pharmacology, Toxicology and Biochemistry. After an introduction from world-renowned experts, the book's chapters cover the balancing role in reduction/oxidation mitochondria play, mitochondria as targets for therapeutics through its metabolism, mitochondrial contributions to the cell death process, mitochondrial response to environmental toxicants, the mitochondrial role in aging, the impact of calorie restrictive diets, new advances in the identification of altered mitochondria associated signaling pathways in carcinogenesis, and much more. This book provides bioscientists new horizons to realize the importance of mitochondria in present-day research on therapies dealing with mitochondria associated chronic diseases, including diabetes, cancer and neurodegenerative disorders. Details the significant role of mitochondria in chronic diseases Presents new insights on the targeting of mitochondria for therapeutic purposes Includes updated results on mitotherapy and other mitochondria-oriented therapies

Mitochondria are essential organelles in eukaryotic cells that control such diverse processes as energy metabolism, calcium buffering, and cell death. Recent studies have revealed that changes in mitochondrial morphology by fission and fusion, a process known as mitochondrial dynamics, is particularly important for neuronal function and survival. Defects in this process are commonly found in neurodegenerative diseases, offering a new paradigm for investigating mechanisms of neurodegeneration. To provide researchers working on neurodegenerative diseases and mitochondria with updated information on this rapidly progressing field, we have invited experts in the field to critically review recent progresses and identify future research directions. The topics include genetics of mitochondrial dynamics, mitochondrial dynamics and bioenergetics, autophagy, apoptosis, and axonal transport, and its role in neurological diseases, including Alzheimer’s, Parkinson’s, and Huntington’s diseases.

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.