Biology subjects

Villalobos-Cantor, S.

Publications and source records attributed to Villalobos-Cantor, S..

4 recordsLinked to original sources

bioRxiv2025

Genetic basis of maneb-induced dopaminergic neurodegeneration in Drosophila

Parkinsons disease (PD) is a complex neurodegenerative disease driven by combined genetic and environmental factors. Human studies support increased PD risk following exposure to the pesticide maneb yet animal studies generally report subtle or no dopaminergic phenotypes unless maneb is combined with additional pesticides. Consequently, it is unclear whether exposure to maneb alone promotes dopamine (DA) neurodegeneration and if so, what the underlying mechanisms are. We hypothesized that gene-environment interactions are major determinants of maneb-mediated neurodegeneration and in support of this find that DA neuron viability is quantitatively divergent among 186 maneb-exposed genetically varying fly strains from the Drosophila Genetic Reference Panel (DGRP). Through genome-wide association analysis we identify several candidate genetic modifiers of maneb-induced DA neurodegeneration and further validate two candidate genes, fz2 and CG14186 which we find potentiate maneb-induced DA neurodegeneration when knocked-down. fz2 and the mammalian ortholog of CG14186 (TMEM237) are both thought to be necessary for intact Wnt pathway signaling in nervous system development and maintenance. Accordingly, we find that adult-specific perturbation of Wnt signaling is sufficient to promote maneb-induced DA neuron loss. Collectively, these results support a role for gene-environment interactions in PD etiology and reveal candidate mediators of maneb-related DA neurodegeneration in vivo. ARTICLE SUMMARYExposure to the pesticide maneb has been linked to increased PD risk although animal models of neurodegeneration have produced mixed results. We developed a Drosophila model for delayed onset dopamine neuron loss following maneb exposure and find that maneb-related neurodegeneration is quantitatively divergent across a large collection of Drosophila strains. We use a genome-wide association approach with follow-up validation to identify candidate modifier genes, uncovering roles for fz2 and CG14186. Both genes are implicated in Wnt signaling and we further show that deregulated Wnt signaling in adults promotes maneb-induced dopamine neuron loss. These studies support a role for gene-environment interactions in maneb neurotoxicity and yield insight into the underlying genes involved.

genetics↗

bioRxiv2025

Genome-wide analysis reveals genes mediating resistance to paraquat neurodegeneration in Drosophila

Parkinsons disease (PD) is thought to develop through a complex interplay of genetic and environmental factors. Epidemiological studies have linked exposure to certain pesticides such as paraquat with elevated PD risk, although how a persons genetic makeup influences disease risk upon exposure remains unknown. Here, we used a genome-wide approach to uncover genes that play a role in resistance to paraquat-induced dopaminergic neurodegeneration in Drosophila. We developed a paraquat exposure model displaying delayed-onset dopaminergic (DA) neurodegeneration to recapitulate this aspect of human disease. We reveal that genetic background is a strong determinant of paraquat-induced DA neurodegeneration susceptibility across a series of nearly 200 fly strains called the Drosophila genetic reference panel (DGRP). Through unbiased genome-wide analysis and follow-up validation, we identify two candidate paraquat resistance genes, luna and CG32264. In gene-level studies, decreased expression of luna or CG32264 is associated with paraquat-induced DA neuron loss while overexpression of either gene prevents neurodegeneration in vivo. The mammalian ortholog of CG32264 is Phactr2, which has previously been linked to human idiopathic PD risk in several populations. Hence, our results reveal genes regulating paraquat-induced DA neuron loss that intersect with human PD risk variants, supporting the potential relevance of our findings to PD and underscoring a role for gene-environment interactions in pesticide-related DA neurodegeneration. ARTICLE SUMMARYParaquat is a widely used herbicide linked to increased PD risk and to dopaminergic neurodegeneration in animal studies. Gene-environment interactions likely influence whether an individual exposed to paraquat eventually manifests PD and presents a major opportunity to yield insight into PD genetics. We developed a paraquat-induced neurodegeneration model in Drosophila, applied this model to nearly 200 fly strains belonging to the Drosophila Genetic Reference Panel and used a genome-wide association approach to identify candidate modifier genes of paraquat-induced dopamine neuron loss which we subsequently validated through RNAi and overexpression functional testing. Through this approach, we reveal two novel paraquat resistance genes, luna and CG32264. Strikingly, the putative mammalian ortholog of CG32264 (Phactr2) was previously linked to human PD, supporting the potential relevance of our findings to human disease.

genetics↗

bioRxiv2022

Rapid Cell Type-Specific Nascent Proteome Labeling in Drosophila

Controlled protein synthesis is required to regulate gene expression and is often carried out in a cell type-specific manner. Protein synthesis is commonly measured by labeling the nascent proteome with amino acid analogs or isotope-containing amino acids. These methods have been difficult to implement in vivo as they require lengthy amino acid replacement procedures. O-propargyl-puromycin (OPP) is a puromycin analog that incorporates into nascent polypeptide chains. Through its terminal alkyne, OPP can be conjugated to a fluorophore-azide for directly visualizing nascent protein synthesis, or to a biotin-azide for capture and identification of newly-synthesized proteins. To achieve cell type-specific OPP incorporation, we developed phenylacetyl-OPP (PhAc-OPP), a puromycin analog harboring an enzyme-labile blocking group that can be removed by Penicillin G acylase (PGA). Here, we show that cell type-specific PGA expression in Drosophila can be used to achieve OPP labeling of newly-synthesized proteins in targeted cell populations within the brain. Following a brief 2-hour incubation of intact brains with PhAc-OPP, we observe robust imaging and affinity purification of OPP-labeled nascent proteins in PGA-targeted cell populations. We apply this method to show a pronounced age-related decline in neuronal protein synthesis in the fly brain, demonstrating the capability to quantitatively capture in vivo protein synthesis states using PhAc-OPP. This method, which we call POPPi (PGA-dependent OPP incorporation), should be applicable for rapidly visualizing protein synthesis and identifying nascent proteins synthesized under diverse physiological and pathological conditions with cellular specificity in vivo.

neuroscience↗

bioRxiv2020

Dietary Amino Acids Impact LRRK2-induced Neurodegeneration in Parkinson's Disease Models

The G2019S mutation in leucine-rich repeat kinase 2 (LRRK2) is a common cause of Parkinsons disease (PD) and results in age-related dopamine neuron loss and locomotor dysfunction in Drosophila melanogaster through an aberrant increase in bulk neuronal protein synthesis. Under non-pathologic conditions, protein synthesis is tightly controlled by metabolic regulation. Whether nutritional and metabolic influences on protein synthesis can modulate the pathogenic effect of LRRK2 on protein synthesis and thereby impact neuronal loss is a key unresolved question. Here, we show that LRRK2 G2019S-induced neurodegeneration is critically dependent on dietary amino acid content. Low dietary amino acid concentration prevents aberrant protein synthesis and blocks LRRK2 G2019S-mediated neurodegeneration in Drosophila and rat primary neurons. Unexpectedly, a moderately high amino acid diet also blocks dopamine neuron loss and motor deficits in Drosophila through a separate mechanism involving stress-responsive activation of 5-AMP-activated protein kinase (AMPK) and neuroprotective induction of autophagy, implicating the importance of protein homeostasis to neuronal viability. At the highest amino acid diet of the range tested, PD-related neurodegeneration occurs in an age-related manner, but is also observed in control strains, suggesting that it is independent of mutant LRRK2 expression. We propose that dietary influences on protein synthesis and autophagy are critical determinants of LRRK2 neurodegeneration, opening up possibilities for future therapeutic intervention.

neuroscience↗