Browsing by Author "Baucum, Anthony J. II"

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    Cell-Specific Spinophilin Function Underlying Striatal Motor Adaptations Associated with Amphetamine-Induced Behavioral Sensitization
    (2022-07) Watkins, Darryl Shumon; Yamamoto, Bryan K.; Atwood, Brady K.; Baucum, Anthony J. II; Hudmon, Andy; Logrip, Marian L.
    Striatal-mediated pathological disease-states such as Obsessive-Compulsive Disorder (OCD), Parkinson’s Disease (PD), and psychostimulant drug addiction/abuse are coupled with distinct motor movement abnormalities. In addition, these disorders are associated with perturbed synaptic transmission. Proper synaptic transmission is critical for maintaining neuronal communication. Furthermore, in many striatal-dependent disease-states, the principle striatal neurons, medium spiny neurons (MSNs), exhibit differential perturbations in downstream signaling. Signal transduction pathways that are localized to the glutamatergic post-synaptic density (PSD) of GABAergic MSNs regulate protein phosphorylation in a tightly controlled manner. Alterations in the control of this phosphorylation in striatal MSNs are observed in myriad striatal pathological diseasestates and can give rise to perturbations in synaptic transmission. While serine/threonine kinases obtain substrate specificity, in part, by phosphorylating specific consensus sites, serine/threonine phosphatases such as protein phosphatase 1 (PP1) are much more promiscuous. To obtain substrate selectivity, PP1 associates with targeting proteins. The major targeting protein for PP1 in the PSD of striatal dendritic spines is spinophilin. Spinophilin not only binds PP1, but also concurrently interacts with myriad synaptic proteins. Interestingly, dopamine depletion, an animal model of PD, modulates spinophilin protein-protein interactions in the striatum. However, spinophilin function on basal striatal-mediated motor behaviors such as the rotarod or under hyperdopaminergic states such as those observed following psychostimulant-induced behavioral sensitization are less well characterized. To elucidate spinophilin function more specifically, we have generated multiple transgenic animals that allow for cell type-specific loss of spinophilin as well as cell-specific interrogation of spinophilin protein interactions. Here, I report the functional role of spinophilin in regulating striatal mediated motor behaviors and functional changes associated with amphetamine-induced locomotor sensitization. In addition, we define changes in spinophilin protein-protein interactions that may mediate these behavioral changes. Furthermore, global loss of spinophilin abrogates amphetamine-induced sensitization and plays a critical role in striatal motor learning and performance. The data suggest that the striatal spinophilin protein interactome is upregulated in MSNs following psychostimulant administration. In addition, loss of spinophilin changes protein expression in myriad psychostimulant-mediated striatal adaptations. Taken together the data suggests that spinophilin’s protein-protein interactions in the striatum are obligate for appropriate striatal mediated motor function.
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    Multisystem Effects of Mold Inhalation: A Convergence on the Central Nervous System
    (2020-08) Ladd, Thatcher Bondi; Oblak, Adrian L.; Yoder, Karmen K.; Baucum, Anthony J. II; Truitt, William; Landreth, Gary
    With urbanization, indoor exposure to microbial communities has changed significantly. While indoor bacterial exposure has decreased, indoor fungal exposure has increased. Along with increases in fungal species diversity, indoor air in urbanized countries is characterized by 1,000+ fold differences in mold spore density between buildings. Americans are estimated to spend ~87% of their lives in this new indoor environment, where airborne spore concentrations are unregulated. While the effects of mold exposure on certain respiratory diseases are well established, little is known about how inhaled mold affects extra-respiratory disease. Mold exposure is associated with central nervous system (CNS) symptoms in humans, but very little is known about how mold affects the CNS. Here, I show that subchronic inhalation of a common indoor mold, Aspergillus versicolor, causes neuroinflammatory gene transcription in five out of five brain regions tested, at both 1 and 2 days post inhalation. How peripheral inflammation from mold inhalation causes neuroinflammation is unknown. The mechanisms by which mold is inhaled and cleared implicate the lung, systemic circulation, and gastrointestinal tract as potential areas of immune response. After mold spores are inhaled and deposited in the lung, they are killed by antifungal immunity, cleared from the lung by the mucociliary escalator, swallowed, and excreted through the gastrointestinal tract. Molds produce many mycotoxins which enter enterohepatic recirculation with known toxic effects, including intestinal epithelial disruption. Mycotoxin concentrations in food are regulated in countries comprising ~85% of the world’s population. Inhaled molds produce these same mycotoxins, yet pulmonary exposure is unregulated. The multi-system effects of fungal exposure are poorly understood, and are part of a growing nascent field. Here, I discuss the current state of the indoor fungal environment, known health effects of mold exposure, how fungi activate the immune system, the CNS effects of a common indoor mold, how neuroinflammation from mold exposure might be occurring, future work needed for the systematic analysis of the CNS effects of mold, what is needed to determine the extent to which fungal exposure influences disease, and what might be done to mitigate those effects.