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(involved in cell migration) was found in astrocytes and monocyte-derived macrophages. IL-6 (involved
in inflammation) was only present in neurons treated with these EVs (i.e., 100k > 10k > 2k). HTLV-1 EVs
were able to facilitate HTLV-1 viral spread in monocytic cell-derived dendritic cells via cell-cell contact.
Finally, an increase in proviral DNA and RNA levels in humanized mice tissue (i.e., Blood, Lymph Node,
and Spleen) were noticed following treatment with 2k and 10k HTLV-1 EVs, indicating the importance
of these EVs in HTLV-1 spread. These findings indicate that different HTLV-1 EV subpopulations induce
cytokine expression, tissue damage, and viral spread. These EV subpopulations could potentially contribute
to the development of ATLL or HAM/TSP. Further mechanistic understanding of these EVs in HTLV-1
pathogenesis will be discussed for the development of preventative measures and treatment options for this
devastating disease.

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1. Gallo RC. Research and discovery of the first human cancer virus, HTLV-1. Best Pract Res Clin Haematol 2011;24:559-65.
2. Gessain A, Cassar O. Epidemiological aspects and world distribution of HTLV-1 infection. Front Microbiol 2012;3:388.
3. Jaworski E, Narayanan A, Van Duyne R, et al. Human T-lymphotropic virus type 1-infected cells secrete exosomes that contain tax
protein. J Biol Chem 2014;289:22284-305.
4. Pinto DO, DeMarino C, Pleet ML, et al. HTLV-1 extracellular vesicles promote cell-to-cell contact. Front Microbiol 2019;10:2147.

9. Proteomics of cerebellar exosomal proteins: therapeutic and biomarker implications in
spinocerebellar ataxia-1

Authors: Ribhav Mishra, Puneet Opal
E-mail: ribhav.mishra@northwestern.edu
Affiliations: Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Abstracts: Exosomes are observed to carry proteins, RNA, and also some chromosomal DNA released
by cells. These biomolecules are found to travel from one cell to another and thus acts as a messenger
to communicate signals between different cells. In the nervous system, they are found to be critical
for neuron-neuron, neuron-glia communications. The emerging roles of exosomes in different
neurodegenerative pathologies like Alzheimer’s, Parkinson, and Prion suggests that exosomes can help in
the spread of these toxic proteinaceous inclusions and hence they are a potential therapeutic target in such
diseases. Exosomal biology in the diseases of Spinocerebellar ataxia-1 (SCA1) is not understood with no
report present to define the role of exosomes in the SCA1 pathology. Since cerebellar cells are the primary
cells affected in the SCA1, hence, we have characterized the exosomes isolated from the primary mixed
culture of cerebellar cells using a variety of biochemical methods and biophysical techniques. Furthermore,
we have identified the proteomic content of the exosomal lysate using the LC-MS/Mass Spectrometry and
have found proteins that are enriched for the biological functions in the extracellular matrix, myelin sheath
formation, axonal growth cone development. We will use this data to identify proteins that are necessary
for the development and functions of the cerebellum and can derive a conclusion on the role of exosomes
in SCA1. Exosomes also carry molecules that are relevant to disease-specific diagnosis and so they are
also proposed as a biomarker tool in neurodegenerative pathologies of Alzheimer’s, Parkinson. However,
their role as a biomarker candidate in SCA1 pathology is not defined and their use of a biomarker strategy
is tested for the very first time by us. To validate exosomes as a biomarker in SCA1 pathology, we plan to
isolate and characterize exosomes from the body fluids (blood and CSF) of WT 2Q/2Q and SCA1 154Q/2Q knock-
in mouse models in different age groups of pre-symptomatic, early symptomatic, and late symptomatic.
The exosomal proteins will be identified using the various proteomics-based approach and then compared
between WT 2Q/2Q and SCA1 154Q/2Q knock-in mice and any alterations in the level of proteins will be studied
further for use as a biomarker in SCA1 pathology. The results of the above work will also be tested as a
biomarker candidate in SCA1 patients. The overall findings of our work will provide clues on the role of
exosomes in the pathology of SCA1 and may well establish them as a biomarker in the pathology of SCA1.