Lightning Oral Talk 25th Annual Lorne Proteomics Symposium 2020

Revealing the proteome of brain derived exosomes isolated from human amyotrophic lateral sclerosis post-mortem tissues (#61)

Natasha Vassileff 1 , Kolin Harinda Rajapaksha 1 , Mitch Shambrook 1 , Amirmohammad Nasiri Kenari 1 , Jacky Chan 2 , Catriona Mclean 2 3 , Andrew Hill 1 , Laura Vella 2 , Lesley Cheng 1
  1. La Trobe Institute for Molecular Science, Bundoora, VICTORIA, Australia
  2. The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
  3. Department of Anatomical Pathology, Alfred Health, Melbourne, Victoria, Australia

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterised by the deposition of misfolded proteins in the motor cortex and motor neurons. Although a multitude of ALS-associated mutated proteins have been identified, few have been linked to exosomes, a form of extracellular vesicles involved in inter-cellular communication. Additionally, the role of exosomes in ALS is undetermined, specifically in relation to pathogenic stress granule formation, a response to cellular stress involving aggregation of non-coding RNAs and their RNA binding proteins. Therefore, this study aimed to determine the proteome of brain derived exosomes (BDEs) isolated from ALS subjects and identify novel ALS-associated deregulated proteins and their potential contributions to pathogenic pathways in ALS. BDEs were isolated from human post-mortem ALS (n=10) and control (n=5) motor cortex brain tissues through a novel ultracentrifugation protocol (1). Following thorough characterisation, BDEs successfully met the minimum criteria required by The International Society for Extracellular Vesicles to be classified as exosomes (2). The BDEs’ protein content subsequently underwent mass spectrometry analysis, allowing for a panel of novel ALS-associated proteins to be identified. This panel consisted of 16 statistically significant differentially packaged proteins identified in the ALS BDEs compared to the control BDEs. This included several up-regulated RNA binding proteins which were determined through pathway analysis to be associated with stress granule dynamics. The identification of these RNA binding proteins in the ALS BDEs suggests there may be a relationship between ALS-associated stress granules and ALS BDE packaging, highlighting a potential role for exosomes in the pathogenesis of ALS.

  1. 1. Vella LJ, Scicluna BJ, Cheng L, Bawden EG, Masters CL, Ang C-S, Willamson N, McLean C, Barnham KJ, Hill AF (2017) A rigorous method to enrich for exosomes from brain tissue. Journal of Extracellular Vesicles 6: 1348885
  2. 2. Lötvall J, Hill AF, Hochberg F, Buzás EI, Di Vizio D, Gardiner C, Gho YS, Kurochkin IV, Mathivanan S, Quesenberry P, Sahoo S, Tahara H, Wauben MH, Witwer KW, Théry C (2014) Minimal experimental requirements for definition of extracellular vesicles and their functions: a position statement from the International Society for Extracellular Vesicles. Journal of Extracellular Vesicles 3: 26913