Linkage-specific ubiquitylation patterns as highly sensitive markers for neurodegenerative disease

Linkage specific ubiquitylation patterns as highly sensitive markers for neurodegenerative disease Abstract Despite an intensive effort by the government pharmaceutical companies and academic groups the diagnosis and treatment of Alzheimerandapos s disease remains elusive The incidence of Alzheimerandapos s disease is predicted to increase reaching more than million cases in USA by Thus the development of quantitative simple and reproducible diagnostic markers is extremely important Current methods for diagnosis of Alzheimerandapos s disease are dependent on clinical and neuropsychological assessment cerebrospinal fluid CSF analysis and brain imaging procedures all of which have significant cost and access to care barriers Thus the need for simple blood based biomarkers has never been greater We hypothesize that dysfunction in the ubiquitin proteasome pathway occurs decades before the clinical manifestation of Alzheimerandapos s disease symptoms Neurons generally do not divide and their survival depends heavily on the removal of misfolded proteins The first step in neurodegenerative disease begins with a diminished response to unfolded protein removal and proteasomal dysfunction Therefore neuronal diseases are marked by the appearance or change in pattern of ubiquitylated proteins the main hypothesis of this proposal which describes a unique combination of affinity purification of ubiquitylated proteins and mass spectroscopy approaches to detect ubiquitylated proteins and also determine the nature of the poly ubiquitin chain linkage Although the roles of the ubiquitin pathway in cell physiology and pathology have been recognized for the last three decades surprisingly there are no reliable and sensitive methods available to monitor patterns of ubiquitylation The development of this technology will enable clinicians to make early diagnoses of Alzheimerandapos s disease facilitate the discovery of disease modifying drugs and open doors for cell biologists to rapidly identify patterns of poly ubiquitylated proteins in tissues cells or body fluids PUBLIC HEALTH SIGNIFICANCE The proposed studies are based on the hypothesis that changes in the pattern of ubiquitylation of certain proteins both in extent and in the structure of the polyubiquitin chains appear early on in the onset of neurodegenerative diseases especially Alzheimers Disease AD Identification of these changes by a combination of linkage specific polyubiquitin affinity based purification matrices and high resolution quantitative mass spectrometry should provide lead markers for the development of diagnostic tests for the early detection of AD and new therapeutic approaches