Role of CHIP in the proteome in a neuronal cell model
Ageing is an important risk factor in the occurrence of neurodegenerative diseases and the proportion of the population suffering from these disorders is increasing. The main aim of this project is to study the role of proteostasis in neuronal cell health and specifically to investigate the role of CHIP, an E3 ligase, in protein homeostasis and cell growth parameters. Although there is evidence that CHIP is related to several pathologies, such as Parkinson’s and Huntington’s disease, the mechanism by which CHIP impacts these conditions is not yet well established. CHIP is a homodimeric quality control E3 ubiquitin ligase that occupies a critical axis in maintenance of cell homeostasis due to its role linking degradation to the protein chaperone machinery. Studies in mouse models have shown that CHIP knock out mice are characterised by accelerated anatomical ageing and cellular senescence, increased protein aggregation and protein oxidation. However, how loss of CHIP function contributes to health or disease in human neurons remains largely unstudied. In this project, CHIP null SHSY5Y cells were generated using CRISPR/Cas9 technology and provide a platform for studying cell growth parameters. Real-time proliferation measurements revealed that CHIP is implicated in neuronal cell growth. Moreover, the level of oxidised proteins in these cells is increased. A comparative proteomic approach to define CHIP-dependent changes in the neuronal proteome showed high levels of neurotrophins in CHIP null cells, which adds to the known list of CHIP functions in human neuronal cell health. In summary, this study shows novel work in the role of CHIP in a neuronal cell model, which may be physiologically relevant in health and disease.