TAF15

A new study led by the Medical Research Council's (MRC) Laboratory of Molecular Biology (LMB) has identified a new protein as a potential therapeutic target for frontotemporal dementia, a type of early-onset dementia. Dementia is a progressive neurodegenerative disorder that affects more than 944,000 people in the UK. Frontotemporal dementia occurs from the degeneration of the frontal and temporal lobes of the brain, which control emotions, personality and behaviour, along with speech. Most neurodegenerative diseases involve proteins aggregating into filaments known as amyloids. When identified, researchers can target these proteins for diagnostic tests and treatments. However, in around 10% of frontotemporal dementia cases, researchers had to identify the TAF15 protein. Published in Nature , MRC LMB researchers successfully pinpointed the aggregated structures of the protein using cutting-edge cryo-electron microscopy to study the brains of four patients who had this type of early-onset dementia. The FUS protein is already known to be associated with frontotemporal dementia. However, researchers were surprised to identify the TAF15 protein in the four brains. Additionally, this type of early-onset dementia can sometimes be seen in people living with motor neurone disease (MND), a condition that affects the brain and nerves. Researchers studied two of the individuals who donated their brains who had signs of both diseases and identified the same aggregated structure of TAF15 in brain regions associated with MND. The identification of these proteins and the basic structures of these filaments in this form of early-onset dementia could lead to the development of early diagnostic tests and drugs to combat their formation. Dr Benjamin Ryskeldi-Falcon, study lead at the MRC LMB, said: “Now that we know the key protein and its structure, we have the potential to develop tools to screen for these abnormal protein aggregates in hundreds of patient samples to test how widespread they are” and “start to target it for the diagnosis and therapy of this type of frontotemporal dementia”. The study was funded by the MRC, along with Alzheimer’s Research UK, the US National Institute of Health, the Alzheimer’s Society, the Association for Frontotemporal Degeneration, the Swiss National Science Foundation and the Levehulme Trust.

An international team of researchers has identified a protein found in the brains of people with frontotemporal dementia (FTD), discovering a new target for potential treatments for the disease. An international team of researchers including experts at the Indiana University School of Medicine has identified a protein found in the brains of people with frontotemporal dementia (FTD), discovering a new target for potential treatments for the disease. According to the National Institutes of Health, FTD results from damage to neurons in the frontal and temporal lobes of the brain. People with this type of dementia typically present symptoms, including unusual behaviors, emotional problems, trouble communicating, difficulty with work or in some cases difficulty with walking, between the ages of 25 and 65. Neurodegenerative disorders, including dementias and Amyotrophic Lateral Sclerosis (ALS), occur when specific proteins form amyloid filaments in the nerve cells of the brain and spinal cord. The multidisciplinary team of researchers -- including members from the Medical Research Council (MRC) Laboratory of Molecular Biology, the IU School of Medicine and the University College London Queen Square Institute of Neurology -- found that in cases of FTD, a protein called TAF15 forms these amyloid filaments in the cells of the brain and the spinal cord. On December 6, they published their findings in Nature. Bernardino Ghetti, MD is a Distinguished Professor at the IU School of Medicine and has been studying neurodegenerative dementias for 50 years. As a lead neuropathologist on the project, Ghetti and his team studied the protein aggregates from brains donated by four people who had frontotemporal dementia and motor weakness. Together with their colleagues in the UK, IU researchers used neuropathologic and molecular techniques and cutting-edge cryo-electron microscopy (cryo-EM) at atomic resolution to discover the presence of the amyloid filaments made of TAF15 protein in multiple brain areas. However it is important to note that TAF15 amyloid affects also nerve cells of the motor system. "This discovery represents an important breakthrough that recognizes TAF15 as a potential target for the development of diagnostic and therapeutic strategies toward a lesser-known form of frontotemporal lobar degeneration associated with frontotemporal dementia," Ghetti said. Additional authors on the study are the MRC Laboratory of Molecular Biology's Stephan Tetter, Diana Arseni, Alexey G. Murzin, Sew Y. Peak-Chew and Benjamin Ryskeldi-Falcon; the University College London's Yazead Buhidma and Tammaryn Lashley; and the IU School of Medicine's Holly J. Garringer, Kathy L. Newell, Ruben Vidal and Liana G. Apostolova. The study was in part funded by the NIH's National Institute on Aging and National Instiute of Neurological Disorders and Stroke.

Scientists have identified abnormal aggregates of a protein called TAF15 in the brains of individuals with early-onset dementia, known as frontotemporal dementia, where the cause was not previously known. Most neurodegenerative diseases, including dementias, involve proteins aggregating into filaments called amyloids. In most of these diseases, researchers have identified the proteins that aggregate, allowing them to target these proteins for diagnostic tests and treatments. But, in around 10% of cases of frontotemporal dementia, scientists had yet to identify the rogue protein. Now, scientists have pinpointed aggregated structures of the protein TAF15 in these cases. Frontotemporal dementia results from the degeneration of the frontal and temporal lobes of the brain, which control emotions, personality and behaviour, as well speech and understanding of words. It tends to start at a younger age than Alzheimer's disease, often being diagnosed in people aged 45 to 65, although it can also affect younger or older people. In a paper published today in the journal Nature, research led by scientists from the Medical Research Council (MRC) Laboratory of Molecular Biology, in Cambridge, UK, has identified aggregated structures of a protein that could provide a target for the future development of diagnostic tests and treatments. Dr Benjamin Ryskeldi-Falcon, who led the study at the MRC Laboratory of Molecular Biology, said: "This discovery transforms our understanding of the molecular basis of frontotemporal dementia. It is a rare finding of a new member of the small group of proteins known to aggregate in neurodegenerative disease. "Now that we have identified the key protein and its structure, we can start to target it for the diagnosis and therapy of this type of frontotemporal dementia, similar to strategies already in the pipeline for targeting the aggregates of amyloid-beta and tau proteins that characterise Alzheimer's disease." The scientists used cutting-edge cryo-electron microscopy (cryo-EM) to study protein aggregates from the brains of four people who had this type of frontotemporal dementia at atomic resolution. The donated brains were identified by Tammaryn Lashley at the University College London Queen Square Institute of Neurology and Bernardino Ghetti at the Indiana University School of Medicine. In this type of dementia, scientists had long thought that a protein called FUS aggregated, based on similarities with other neurodegenerative diseases. Using cryo-EM, the researchers at the MRC Laboratory of Molecular Biology were able to identify that the protein aggregates from each brain had the same atomic structure. Surprisingly, the protein was not FUS -- it was another protein called TAF15. Dr Stephan Tetter, also from the MRC Laboratory of Molecular Biology, who is first author on the paper, said: "This is an unexpected result because, before this study, TAF15 was not known to form amyloid filaments in neurodegenerative diseases and no structures of the protein existed. Cryo-EM is transforming our understanding of the molecular pathology of dementia and neurodegenerative diseases more broadly by giving us insights that were beyond the capabilities of previous technologies." Dr Ryskeldi-Falcon added: "The technical challenge of performing cryo-EM meant that we were only able to look at the brains of four individuals. However, now that we know the key protein and its structure, we have the potential to develop tools to screen for these abnormal protein aggregates in hundreds of patient samples to test how widespread they are." Frontotemporal dementia and motor neuron disease Some people who have frontotemporal dementia also have motor neuron disease, a condition in which individuals progressively lose control over their muscles. In this study, two of the individuals who donated their brains had signs of both diseases. For these individuals, the researchers identified the same aggregated structure of TAF15 in brain regions associated with motor neuron disease. Dr Ryskeldi-Falcon said: "The presence of the same TAF15 aggregates in two individuals who had frontotemporal dementia and signs of motor neuron disease raises the possibility that TAF15 may contribute to both diseases. We are now studying whether aberrant aggregated TAF15 is present in people who have motor neurone disease in the absence of frontotemporal dementia." This study was funded by the Medical Research Council, Alzheimer's Research UK, the US National Institutes of Health, the Alzheimer's Society, the Association for Frontotemporal Degeneration, the Swiss National Science Foundation, and the Leverhulme Trust. Dr Charlotte Durkin, Head of the Medical Research Council's Molecular and Cellular Medicine Board, said: "Decades of world-leading research at the MRC Laboratory of Molecular Biology brought the breakthrough of cryoelectron microscopy -- gaining Dr Richard Henderson a Nobel Prize in 2017. This latest study identifying the protein linked to a type of frontotemporal dementia continues the MRC LMB's success in elucidating dementia-related protein structures by cryoEM, which includes the first structure for the key dementia protein tau. Knowing the identity and basic structure of these filaments in this rare form of early-onset dementia is vital to developing early diagnostic tests and drugs to combat their formation."