Amyloid beta denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid-beta precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ in a cholesterol-dependent process and substrate presentation. Aβ molecules can aggregate to form flexible soluble oligomers which may exist in several forms. It is now believed that certain misfolded oligomers can induce other Aβ molecules to also take the misfolded oligomeric form, leading to a chain reaction akin to a prion infection. The oligomers are toxic to nerve cells. The other protein implicated in Alzheimer's disease, tau protein, also forms such prion-like misfolded oligomers, and there is some evidence that misfolded Aβ can induce tau to misfold.
Amyloid-beta precursor protein (APP) is an integral membrane protein expressed in many tissues and concentrated in the synapses of neurons. It functions as a cell surface receptor and has been implicated as a regulator of synapse formation, neural plasticity, antimicrobial activity, and iron export. It is coded for by the gene APP and regulated by substrate presentation. APP is best known as the precursor molecule whose proteolysis generates amyloid beta (Aβ), a polypeptide containing 37 to 49 amino acid residues, whose amyloid fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer's disease patients.
Amyloid plaques are extracellular deposits of the amyloid beta (Aβ) protein mainly in the grey matter of the brain. Degenerative neuronal elements and an abundance of microglia and astrocytes can be associated with amyloid plaques. Some plaques occur in the brain as a result of aging, but large numbers of plaques and neurofibrillary tangles are characteristic features of Alzheimer's disease. The plaques are highly variable in shape and size; in tissue sections immunostained for Aβ, they comprise a log-normal size distribution curve, with an average plaque area of 400-450 square micrometers (μm2). The smallest plaques, which often consist of diffuse deposits of Aβ, are particularly numerous. Plaques form when Aβ misfolds and aggregates into oligomers and longer polymers, the latter of which are characteristic of amyloid.
A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple system atrophy, tauopathies, and prion diseases. Neurodegeneration can be found in the brain at many different levels of neuronal circuitry, ranging from molecular to systemic. Because there is no known way to reverse the progressive degeneration of neurons, these diseases are considered to be incurable; however research has shown that the two major contributing factors to neurodegeneration are oxidative stress and inflammation. Biomedical research has revealed many similarities between these diseases at the subcellular level, including atypical protein assemblies and induced cell death. These similarities suggest that therapeutic advances against one neurodegenerative disease might ameliorate other diseases as well.
Karen K. Hsiao Ashe is a professor at the Department of Neurology and Neuroscience at the University of Minnesota (UMN) Medical School, where she holds the Edmund Wallace and Anne Marie Tulloch Chairs in Neurology and Neuroscience. She is the founding director of the N. Bud Grossman Center for Memory Research and Care, and her specific research interest is memory loss resulting from Alzheimer's disease and related dementias. Her research has included the development of an animal model of Alzheimer's.
Christine Van Broeckhoven is a Belgian molecular biologist and professor in Molecular genetics at the University of Antwerp. She is also leading the VIB Department of Molecular Genetics, University of Antwerp of the Flanders Institute for Biotechnology (VIB). Christine Van Broeckhoven does research on Alzheimer dementia, bipolar mental disorders and other neurological diseases. Since 1983 she has had her own laboratory for molecular genetics at the University of Antwerp, and since 2005 is focussing her research on neurodegenerative brain diseases. She is an associate editor of the scientific journal Genes, Brain and Behavior.
Sir John Anthony Hardy is a human geneticist and molecular biologist at the Reta Lila Weston Institute of Neurological Studies at University College London with research interests in neurological diseases.
Bart De Strooper is a Belgian molecular biologist and professor at Vlaams Instituut voor Biotechnologie and KU Leuven and the UK Dementia Research Institute and University College London, UK. De Strooper's research seeks to translate genetic data into the identification and treatment of neurodegenerative diseases and treatments. interest are the secretases, proteases which cleave the amyloid precursor protein (APP), resulting in amyloid peptides.
Sir Christopher Martin Dobson was a British chemist, who was the John Humphrey Plummer Professor of Chemical and Structural Biology in the Department of Chemistry at the University of Cambridge, and Master of St John's College, Cambridge.
Peter Henry St George-Hyslop, OC, FRS, FRSC, FRCPC, is a British and Canadian medical scientist, neurologist and molecular geneticist who is known for his research into neurodegenerative diseases. St George-Hyslop is one of the most cited authors in the field of Alzheimer's disease research. He has identified a number of key genes that are responsible for nerve cell degeneration and early-onset forms of Alzheimer's disease. These include the discovery of the presenilins, Nicastrin, and SORL1 genes. Presenilin mutations are the most common cause of familial Alzheimer's disease. St George-Hyslop also co-led the discovery of the gene for the amyloid precursor protein.
Roger Sidney Goody is an English biochemist who served as director at the Max Planck Institute for Molecular Physiology in Dortmund from 1993 until 2013. Since 2013 he is Emeritus Director of the institute.
Kai Simons is a Finnish professor of biochemistry and cell biology and physician, living and working in Germany. He introduced the concept of lipid rafts, and coined the term trans-Golgi network. He is the co-founder and co-organizer of the European Molecular Biology Laboratory and European Molecular Biology Organization, and initiated the foundation of Max Planck Institute of Molecular Cell Biology and Genetics.
Virginia Man-Yee Lee is a Chinese-born American biochemist and neuroscientist who specializes in the research of Alzheimer's disease. She is the current John H. Ware 3rd Endowed Professor in Alzheimer's Research at the Department of Pathology and Laboratory Medicine, and the director of the Center for Neurodegenerative Disease Research and co-director of the Marian S. Ware Alzheimer Drug Discovery Program at the Perelman School of Medicine, University of Pennsylvania. She received the 2020 Breakthrough Prize in Life Sciences.
Chester Mathis is an American chemist who is currently the Distinguished Professor of Radiology at University of Pittsburgh and holds the UPMC Endowed Chair of PET Research.
James Francis Gusella is a Canadian molecular biologist and geneticist known for his work on Huntington's disease and other neurodegenerative diseases in humans. He is the Bullard Professor of Neurogenetics in the Department of Genetics at Harvard Medical School and an investigator at the Center for Genomic Medicine at the Mass General Research Institute.
Colin Louis MastersMD is an Australian neuropathologist who researches Alzheimer's disease and other neurodegenerative disorders. He is laureate professor of pathology at the University of Melbourne.
Eva-Maria Mandelkow is a German neuroscientist and Alzheimer's disease researcher at the German Center for Neurodegenerative Diseases (DZNE), Bonn.
Mathias Jucker is a Swiss neuroscientist, Professor, and a Director at the Hertie Institute for Clinical Brain Research of the University of Tübingen. He is also a group leader at the German Center for Neurodegenerative Diseases in Tübingen. Jucker is known for his research on the basic biologic mechanisms underlying brain aging and Alzheimer's disease.
Lary Walker is an American neuroscientist and researcher at Emory University in Atlanta, Georgia. He is Associate Director of the Goizueta Alzheimer's Disease Research Center at Emory, and he is known for his research on the role of abnormal proteins in the causation of Alzheimer's disease.
Dennis J. Selkoe is an American physician (neurologist) known for his research into the molecular basis of Alzheimer's disease. In 1985 he became Co-Director of the Center for Neurological Diseases and from 1990, Vincent and Stella Coates Professor of Neurological Diseases at Harvard Medical School. He is also a Fellow of the AAAS and a member of the National Academy of Medicine.
