PROJECT SUMMARY/ABSTRACT
The consequences of prenatal alcohol exposure for the immature central nervous system represents a
devastating but likely underestimated public health hazard, producing a range of ethanol-induced
developmental defects including cognitive impairments having long-term impacts on society. Damage to
neurons also includes cells within the retina, producing visual system facets of these fetal alcohol spectrum
disorders (FASD). Critical gaps in knowledge remain regarding the specific mechanisms underlying ethanol-
mediated damage to neurons, and their intrinsic vulnerabilities and neuroprotective features, which might be
monitored, enhanced and/or exploited in some way to rescue neurons from damage. One proposed cellular
target for ethanol damage is disruption in neurons of critical protein homeostasis pathways including the
ubiquitin system. Our long-term goal is develop an understanding of the molecules and mechanisms
producing photoreceptor neuron dysfunction and degeneration, and to elucidate potential rescue strategies.
The overall objective of the current proposal is to determine the contribution of ubiquitin-system impairment
to tissue damage by ethanol in these specific neurons, and the feasibility of ubiquitin-system manipulations
to rescue neuronal function. The central hypothesis of our proposal is that binge-like ethanol exposure
disrupts fundamental protein turnover mechanisms in photoreceptor neurons, undermining normal cell
proteostasis. Our hypothesis is based on preliminary data from our lab demonstrating that binge-like
exposure to ethanol produces loss of visual function in larval zebrafish, an advantageous model for FASD,
with partial rescue of function via pharmacological enhancement of autophagy and the ubiquitin-proteasome
system; ubiquitin-system impairment in photoreceptor-derived cells and photoreceptor neurons after ethanol
exposure; and previously reported evidence for ubiquitin-system changes in the brain with ethanol. We plan
to test our central hypothesis and accomplish the main objective of this proposal by completing the following
specific aims: (1) determine the effects on ubiquitin-system manipulations on cone photoreceptor neuron
function and proteostasis in the context of damaging exposure to alcohol; and (2) interrogate the changing
landscape of ubiquitin-modified proteins in cone photoreceptors following ethanol exposure. These studies
will involve molecular manipulations, including cell-specific expression of reporter proteins for ubiquitin-
system impairment and CRISPR/Cas9 gene disruption specifically in cone photoreceptors; biochemistry;
visual performance assays; ERG recordings; and photoreceptor-specific ubiquitin proteomics. The expected
outcomes of these studies are an enhanced understanding of the relationship between early alcohol
exposure, neuronal damage, and the ubiquitin system, and a mechanistic foundation for the possible
development of therapeutic approaches to mitigate neuronal damage caused by alcohol abuse.