Misfolding Of Amyloid Beta And Tau In Alzheimers And Other Neurodegenerative Diseases

Neurofibrillary tangles (NFTs) composed of intracellular aggregates of tau protein are a key neuropathological feature of Alzheimer’s Disease (AD) and other neurodegenerative diseases, collectively termed tauopathies. The abundance of NFTs has been reported to correlate positively with the severity of cognitive impairment in AD. However, accumulating evidences derived from studies of experimental models have identified that NFTs themselves may not be neurotoxic. Now, many of tau researchers are seeking a “toxic” form of tau protein. Moreover, it was suggested that a “toxic” tau was capable to seed aggregation of native tau protein and to propagate in a prion-like manner. However, the exact neurotoxic tau species remain unclear. Because mature tangles seem to be non-toxic component, “tau oligomers” as the candidate of “toxic” tau have been investigated for more than one decade. In this topic, we will discuss our consensus of “tau oligomers” because the term of “tau oligomers” [e.g. dimer (disulfide bond-dependent or independent), multimer (more than dimer), granular (definition by EM or AFM) and maybe small filamentous aggregates] has been used by each researchers definition. From a biochemical point of view, tau protein has several unique characteristics such as natively unfolded conformation, thermo-stability, acid-stability, and capability of post-translational modifications. Although tau protein research has been continued for a long time, we are still missing the mechanisms of NFT formation. It is unclear how the conversion is occurred from natively unfolded protein to abnormally mis-folded protein. It remains unknown how tau protein can be formed filaments [e.g. paired helical filament (PHF), straight filament and twisted filament] in cells albeit in vitro studies confirmed tau self-assembly by several inducing factors. Researchers are still debating whether tau oligomerization is primary event rather than tau phosphorylation in the tau pathogenesis. Inhibition of either tau phosphorylation or aggregation has been investigated for the prevention of tauopathies, however, it will make an irrelevant result if we don’t know an exact target of neurotoxicity. It is a time to have a consensus of definition, terminology and methodology for the identification of “tau oligomers”.

This book highlights the pathophysiological complexities of the mechanisms and factors that are likely to be involved in a range of neuroinflammatory and neurodegenerative diseases including Alzheimer's disease, other Dementia, Parkinson Diseases and Multiple Sclerosis. The spectrum of diverse factors involved in neurodegeneration, such as protein aggregation, oxidative stress, caspases and secretase, regulators, cholesterol, zinc, microglia, astrocytes, oligodendrocytes, etc, have been discussed in the context of disease progression. In addition, novel approaches to therapeutic interventions have also been presented. It is hoped that students, scientists and clinicians shall find this very informative book immensely useful and thought-provoking.

The Molecular and Cellular Basis of Neurodegenerative Diseases: Underlying Mechanisms presents the pathology, genetics, biochemistry and cell biology of the major human neurodegenerative diseases, including Alzheimer’s, Parkinson’s, frontotemporal dementia, ALS, Huntington’s, and prion diseases. Edited and authored by internationally recognized leaders in the field, the book's chapters explore their pathogenic commonalities and differences, also including discussions of animal models and prospects for therapeutics. Diseases are presented first, with common mechanisms later. Individual chapters discuss each major neurodegenerative disease, integrating this information to offer multiple molecular and cellular mechanisms that diseases may have in common. This book provides readers with a timely update on this rapidly advancing area of investigation, presenting an invaluable resource for researchers in the field. Covers the spectrum of neurodegenerative diseases and their complex genetic, pathological, biochemical and cellular features Focuses on leading hypotheses regarding the biochemical and cellular dysfunctions that cause neurodegeneration Details features, advantages and limitations of animal models, as well as prospects for therapeutic development Authored by internationally recognized leaders in the field Includes illustrations that help clarify and consolidate complex concepts

Alzheimer disease causes the gradual deterioration of cognitive function, including severe memory loss and impairments in abstraction and reasoning. Understanding the complex changes that occur in the brain as the disease progressesincluding the accumulation of amyloid plaques and neurofibrillary tanglesis critical for the development of successful therapeutic approaches. Written and edited by leading experts in the field, this collection from Cold Spring Harbor Perspectives in Medicine includes contributions covering all aspects of Alzheimer disease, from our current molecular understanding to therapeutic agents that could be used to treat and, ultimately, prevent it. Contributors discuss the biochemistry and cell biology of amyloid -protein precursor (APP), tau, presenilin, -secretase, and apolipoprotein E and their involvement in Alzheimer disease. They also review the clinical, neuropathological, imaging, and biomarker phenotypes of the disease; genetic alterations associated with the disorder; and epidemiological insights into its causation and pathogenesis. This comprehensive volume, which includes discussions of therapeutic strategies that are currently used or under development, is a vital reference for neurobiologists, cell biologists, pathologists, and other scientists pursuing the biological basis of Alzheimer disease, as well as investigators, clinicians, and students interested in its pathogenesis, treatment, and prevention.

This is the first book to assemble the leading researchers in the field of LRRK2 biology and neurology and provide a snapshot of the current state of knowledge, encompassing all major aspects of its function and dysfunction. The contributors are experts in cell biology and physiology, neurobiology, and medicinal chemistry, bringing a multidisciplinary perspective on the gene and its role in disease. The book covers the identification of LRRK2 as a major contributor to the pathogenesis of Parkinson's Disease. It also discusses the current state of the field after a decade of research, putative normal physiological roles of LRRK2, and the various pathways that have been identified in the search for the mechanism(s) of its induction of neurodegeneration.

The misfolding and aggregation of specific proteins is an early and obligatory event in many of the age-related neurodegenerative diseases of humans. The initial cause of this pathogenic cascade and the means whereby disease spreads through the nervous system, remain uncertain. A recent surge of research, first instigated by pathologic similarities between prion disease and Alzheimer’s disease, increasingly implicates the conversion of disease-specific proteins into an aggregate-prone b-sheet-rich state as the prime mover of the neurodegenerative process. This prion-like corruptive protein templating or seeding now characterizes such clinically and etiologically diverse neurological disorders as Alzheimer ́s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and frontotemporal lobar degeneration. Understanding the misfolding, aggregation, trafficking and pathogenicity of the affected proteins could therefore reveal universal pathomechanistic principles for some of the most devastating and intractable human brain disorders. It is time to accept that the prion concept is no longer confined to prionoses but is a promising concept for the understanding and treatment of a remarkable variety of diseases that afflict primarily our aging society. ​

Alzheimer’s disease is an increasingly common form of dementia and despite rising interest in discovery of novel treatments and investigation into aetiology, there are no currently approved treatments that directly tackle the causes of the condition. Due to its multifactorial pathogenesis, current treatments are directed against symptoms and even precise diagnosis remains difficult as the majority of cases are diagnosed symptomatically and usually confirmed only by autopsy. Alzheimer’s Disease: Recent Findings in Pathophysiology, Diagnostic and Therapeutic Modalities provides a comprehensive overview from aetiology and neurochemistry to diagnosis, evaluation and management of Alzheimer's disease, and latest therapeutic approaches. Intended to provide an introduction to all aspects of the disease and latest developments, this book is ideal for students, postgraduates and researchers in neurochemistry, neurological drug discovery and Alzheimer’s disease.