Abstract

Alzheimer’s
disease (AD) is a neurodegenerative disease that is characterised by massive
neuronal death and a progressive decline of cognitive functions. Currently
available therapeutic treatments offer symptomatic relief to modestly slow the
rate of cognitive impairment but are ineffective at halting the disease
progression. Since neuronal loss contributes to disease progression in AD,
there is interest in developing regenerative treatments that stimulate
neurogenesis. Neurogenesis is an endogenous neuroprotective mechanism that mainly
occurs in the subventricular zone (SVZ) along the lateral ventricles and the
subgranular zone (SGZ) of the dentate gyrus (DG) in the adult hippocampus. An in
vitro phenotypic screen was employed to discover small molecules that could
modulate neurogenesis in SVZ- and DG-derived murine neural stem cells (NSCs). A
hit compound OXS‑N1 found to increase neurogenesis in vitro was also
found to stimulate SGZ neurogenesis after oral administration to wild-type
mice. However, the molecular targets of OXS-N1 and the mechanism of its
proneurogenic activity are unknown. We aim to use a chemoproteomics approach to
elucidate the mechanism of OXS-N1 and probe pathways involved in neurogenesis
and NSC specification.

A series
of affinity probes and fluorescent-tagged derivatives was synthesised to assess
the molecular interactions of OXS-N1 and its localisation in NSCs using
affinity-based protein profiling (AfBPP) and confocal microscopy. We have
identified a hit protein target through pull-down experiments and LC-MS/MS. The
protein target was validated using western blot, and OXS-N1 was found to bind
to a recombinant form of this protein through waterLOGSY and mass spectrometry.
We are doing further target validation studies to understand the mode of
binding to the protein and how this protein is involved in pathways of
neurogenesis.