Biology subjects

Booze, R. M.

Publications and source records attributed to Booze, R. M..

11 recordsLinked to original sources

bioRxiv2026

NLRP3 inflammasome-related microglial pyroptosis in EcoHIV infected mice

HIV-associated neurocognitive disorders (HAND) have become a major clinical concern, particularly among the aging HIV-1-seropositive population, which is generally characterized by persistent viral reservoirs and a lower level of chronic inflammation. NLRP3 inflammasome activation exhibits its unique role in the progression of many chronic inflammatory diseases. Furthermore, pyroptosis, an inflammatory form of programmed cell death, has been implicated in numerous neurological diseases. However, the mechanisms linking EcoHIV infection, microglial pyroptosis, and NLRP3 inflammasome activation remain incompletely understood. In this study, EcoHIV was retro-orbitally injected into C57BL/6J wild-type mice and analyzed at 14-, 30-, 60-, and 90-days post-infection to establish a NeuroHIV model. Additionally, in vitro, BV2 microglial cell line was infected with EcoHIV and treated with MCC950, an inhibitor of the NLRP3 inflammasome, for three days. Pyroptosis marker GSDMD, NLRP3 inflammasome components, Caspase-1 (a marker of inflammasome activation), HLA-DR (an immune activation marker), Programmed-death 1 (PD-1, an immune checkpoint molecule), and Ki67 (a cellular proliferation marker) were assessed by immunofluorescence staining. Results showed that EcoHIV-infected mice showed a peak in NLRP3 expression at 14 days post-infection, compared with controls, followed by a modest decline at 30 days, while GSDMD expression increased progressively across 14 and 30 days. These findings demonstrate dynamic changes in microglial pyroptosis and NLRP3 inflammasome activation over the course of EcoHIV infection. In vitro, EcoHIV-infected BV2 cells exhibited significantly increased EcoHIV-eGFP fluorescence compared with controls, confirming the utility of BV2 cells as an in vitro model of microglial EcoHIV infection. Expression levels of GSDMD and NLRP3 were elevated following infection, indicating enhanced pyroptosis and neuroinflammation. Treatment with MCC950 significantly reduced the expression of GSDMD, NLRP3, HLA-DR, PD-1, and Ki67, suggesting that inhibition of NLRP3 inflammasome activity suppresses both pyroptosis and microglial activation and proliferation. Together, elucidating the interplay between microglial pyroptosis and NLRP3 inflammasome activation may provide new insights into the pathogenesis and potential therapeutic strategies for NeuroHIV in the aging HIV-1-seropositive population.

neuroscience↗

bioRxiv2026

IMPAIRED BRIDGING OF TEMPORAL DISCONTINUITIES IN OLDER ADULT HIV-1 TG RATS

The advent and widespread uptake of combination antiretroviral therapy dramatically changed the epidemiological features of human immunodeficiency virus type 1 (HIV-1), whereby older individuals (>50 years of age) account for approximately 50% of HIV-1 seropositive individuals in the United States. Nevertheless, to date, there is no extant in vivo biological system to model the unique age-related neurocognitive impairments observed in HIV-1 seropositive individuals. Herein, the utility of the HIV-1 transgenic (Tg) rat as a biological system to model age-related neurocognitive impairments and neuroanatomical alterations was evaluated. Older adult HIV-1 Tg rodents (i.e., >12 months of age upon testing initiation), relative to their control counterparts, exhibited profound neurocognitive alterations characterized by impairments in stimulus-reinforcement learning, sustained attention, and selective attention; neurocognitive deficits which support a fundamental distortion of temporal processing. Neuronal dysfunction in older adult HIV-1 Tg animals was characterized by structural alterations in pyramidal neurons, and their associated dendritic spines, in the medial prefrontal cortex and abnormal accumulation of amyloid beta (A{beta}). Interestingly, the abnormal accumulation of A{beta} mechanistically underlies, at least in part, the profound dendritic spine dysmorphology in male, but not female, HIV-1 Tg rats. More critically, however, neuronal dysfunction mechanistically underlies neurocognitive impairments in both male and female HIV-1 Tg rodents, whereby neuronal dysfunction accounts for 65.4% and 60.8% of the variance in neurocognitive function, respectively. Establishing the utility of the HIV-1 Tg rat for age-related neurocognitive impairments is fundamental to disentangling the role of HIV-1 viral proteins and comorbidities in neurocognitive function.

neuroscience↗

bioRxiv2026

A HISTORY OF ADOLESCENT OXYCODONE SELF-ADMINISTRATION: NEURAL MECHANISMS UNDERLYING NEUROCOGNITIVE IMPAIRMENTS

Maturation of the prefrontal cortex and higher-order cognitive processes is ongoing through adolescence and young adulthood; developmental periods associated with the nonmedical use of prescription opioids. Initiation of oxycodone (OXY) self-administration during adolescence induces long-term dose-dependent impairments in neurobehavioral and neurocognitive development. To date, however, the neural mechanisms underlying neurocognitive impairments induced by adolescent prescription opioid use disorder (APOUD) have not been systematically evaluated. A DiOlistic labeling technique, in concert with sophisticated neuronal reconstruction software, revealed a prominent sex- and dose-dependent population shift in the morphological parameters of dendritic spines in pyramidal neurons in the anterior cingulate cortex (ACC) of rodents with a history of adolescent OXY self-administration relative to their control counterparts. Similarly, the biochemical mechanisms underlying dendritic spine dysmorphology, which were investigated using quantitative polymerase chain reaction, were dependent upon biological sex. In male rodents, a dose-dependent decrease in mRNA expression of GRIN1, a N-methyl-D-aspartate receptor, was observed in animals with a history of adolescent OXY self-administration relative to controls. In contrast, female rats with a history of adolescent OXY self-administration exhibited increased mRNA expression of cdk5, a protein kinase involved in the regulation of pre- and post-synaptic function; a transcriptional alteration that may result from excessive glutamate accumulation. Fundamentally, transcriptional dysregulation and dendritic spine dysmorphology mechanistically underlie, at least partly, APOUD-induced neurocognitive impairments. Collectively, results support that sex-dependent glutamatergic dysregulation may underlie dendritic spine dysmorphology in the ACC resulting in APOUD-induced neurocognitive impairments. Glutamatergic dysregulation, therefore, may afford a key target for the development of novel therapeutics. SIGNIFICANCE STATEMENTIndividuals with a history of adolescent prescription opioid use disorder (APOUD) are afflicted with profound neurocognitive impairments. Herein, sex-dependent glutamatergic dysregulation may underlie dendritic spine dysmorphology in the ACC resulting in APOUD-induced neurocognitive impairments, thereby affording a key target for the development of novel therapeutics.

neuroscience↗

bioRxiv2025

S-Equol: A Novel Therapeutic For HIV-1-Associated Gastrointestinal Dysbiosis

HIV-1 infection affects approximately 38.4 million people around the world. The advent of combination anti-retroviral therapy (cART) has greatly improved the quality of life of infected individuals; however, roughly 50% of these individuals will still experience HIV-1-associated neurocognitive disorders (HAND). Additionally, the gastrointestinal microbiome has been reported to be dysbiotic in HIV-1 infected individuals, regardless of adherence to cART. Current research has pointed to the gut-brain-microbiota axis as a potential target to treat both cognitive deficits and microbial changes. The present study investigated S-Equol (SE) as a potential therapeutic for HAND by modulating the gastrointestinal microbiome. The study included 21 HIV-1 Tg rats and 21 F344 control animals to test the effect 0.2mg SE has on cocaine-maintained responding on a PR schedule of reinforcement. Gastrointestinal microbiome alterations between genotypes were found at the phylum and genus level, regardless of treatment group, and SE treatment had both main effects and interactions with genotype. Prevotella_UCG_001 was significantly associated with lever presses for drug, suggesting an effect on motivation for cocaine. Alloprevotella was found to significantly differentiate between genotype by treatment effects, indicating that SE differently affects genotypes.

neuroscience↗

bioRxiv2023

Microglia Proliferation Underlies Synaptic Dysfunction in the Prefrontal Cortex: Implications for the Pathogenesis of HIV-1-Associated Neurocognitive and Affective Alterations

Microglia, which are productively infected by HIV-1, are critical for brain development and maturation, as well as synaptic plasticity. The pathophysiology of HIV-infected microglia and their role in the pathogenesis of HIV-1-associated neurocognitive and affective alterations, however, remains understudied. Three complementary aims were undertaken to critically address this knowledge gap. First, the predominant cell type expressing HIV-1 mRNA in the dorsolateral prefrontal cortex of postmortem HIV-1 seropositive individuals with HAND was investigated. Utilization of a combined RNAscope multiplex fluorescent and immunostaining assay revealed prominent HIV-1 mRNA in microglia of postmortem HIV-1 seropositive individuals with HAND. Second, measures of microglia proliferation and neuronal damage were evaluated in chimeric HIV (EcoHIV) rats. Eight weeks after EcoHIV innoculation, enhanced microglial proliferation was observed in the medial prefrontal cortex (mPFC) of EcoHIV rats, evidenced by an increased number of cells co-localized with both Iba1+ and Ki67+ relative to control animals. Neuronal damage in EcoHIV infected rats was evidenced by pronounced decreases in both synaptophysin and post synaptic density protein 95 (PSD-95), markers of pre-synaptic and post-synaptic damage, respectively. Third, regression analyses were conducted to evaluate whether microglia proliferation mechanistically underlies neuronal damage in EcoHIV and control animals. Indeed, microglia proliferation accounts for 42-68.6% of the variance in synaptic dysfunction. Collectively, microglia proliferation induced by chronic HIV-1 viral protein exposure may underlie the profound synaptodendritic alterations in HIV-1. Understanding how microglia are involved in the pathogenesis of HAND and HIV-1-associated affective disorders affords a key target for the development of novel therapeutics.

neuroscience↗

bioRxiv2022

Motivational Dysregulation with Melanocortin 4 Receptor Haploinsufficiency

Obesity, by any standard, is a global health crisis. Both genetic and dietary contributions to the development and maintenance of obesity were integral factors of our experimental design. As mutations of the melanocortin 4 receptors (MC4R) are the leading monogenetic cause of obesity, MC4R haploinsufficient rats were fed a range of dietary fat (0-12%) in a longitudinal design. Physiological and motivational assessments were performed using a locomotor task, 5-choice sucrose preference task, an operant task with fixed and progressive ratios, as well as a distraction operant task. Dendritic spine morphology of medium spiny neurons (MSNs) of the nucleus accumbens (NAc), cells with ample D1 and D2 receptors, was also assessed. The percentage of lipid deposits in the liver of each rat was also analyzed using the Area Fraction Fractionator probe for stereological measurements. MC4R haploinsufficiency resulted in a phenotypic resemblance for adult-onset obesity that was exacerbated by the consumption of a high-fat diet. Results from the operant tasks indicate that motivational deficits due to MC4R haploinsufficiency were apparent prior to the onset of obesity and exacerbated by dietary fat consumption after obesity was well established. Moreover, MSN morphology shifted to longer spines with smaller head diameters for the MC4R+/- animals under the high-fat diet, suggesting a potential mechanism for the dysregulation of motivation to work for food. Increasing our knowledge of the neural circuitry/mechanisms responsible for the rewarding properties of food has significant implications for understanding energy balance and the development of obesity.

animal behavior and cognition↗

bioRxiv2022

Disrupted Decision-Making: EcoHIV Inoculation Following a History of Cocaine Use

Independently, chronic cocaine use and HIV-1 viral protein exposure induce neuroadaptations in the frontal-striatal circuit; how the frontal-striatal circuit responds to HIV-1 infection following chronic drug use, however, has remained elusive. After establishing a history of both sucrose and cocaine self-administration, a pretest-posttest experimental design was utilized to evaluate preference judgment, a simple form of decision-making dependent upon the integrity of frontal- striatal circuit function. During the pretest assessment, male rats exhibited a clear preference for cocaine, whereas female animals preferred sucrose. Two posttest evaluations (3 Days and 6 Weeks Post Inoculation) revealed that, independent of biological sex, inoculation with chimeric HIV (EcoHIV), but not saline, disrupted decision-making. Prominent structural alterations in frontal-striatal circuit dysfunction were evidenced by synaptodendritic alterations in pyramidal neurons in the medial prefrontal cortex. Thus, the EcoHIV rat affords a biological system to model how the frontal-striatal circuit responds to HIV-1 infection following chronic drug use.

neuroscience↗

bioRxiv2021

SYNAPTIC DYSFUNCTION UNDERLIES ALTERATIONS IN THE INITIATION OF GOAL-DIRECTED BEHAVIORS: IMPLICATIONS FOR HIV-1 ASSOCIATED APATHY

Individuals living with human immunodeficiency virus type 1 (HIV-1) exhibit an increased prevalence of neuropsychiatric comorbities (e.g., apathy) relative to their seronegative counterparts. Given the profound functional consequences associated with apathy, conceptualizing the multidimensional neuropsychiatric syndrome, and associated neural mechanisms, following chronic HIV-1 viral protein exposure remains a critical need. HIV-1 associated apathy was examined by quantifying goal-directed behaviors, indexed using voluntary wheel running, during the diurnal and nocturnal cycle. Apathetic behaviors in the HIV-1 Tg rat were characterized by a profound decrease in the number of running bouts during both the diurnal and nocturnal cycle, supporting a prominent deficit in the self-initiation of spontaneous behaviors. Additionally, HIV-1 Tg animals exhibited a decreased reinforcing efficacy of voluntary wheel running during the nocturnal cycle. Following the completion of voluntary wheel running, synaptic dysfunction in medium spiny neurons (MSNs) of the nucleus accumbens (NAc) was examined as a potential neural mechanism underlying HIV-1 associated apathy. HIV-1 Tg animals displayed prominent synaptic dysfunction in MSNs of the NAc, characterized by decreased synaptic connectivity and a population shift towards an immature dendritic spine phenotype relative to control animals. Synaptic dysfunction accounted for 42.0% to 68.5% of the variance in the number of running bouts affording a key neural mechanism underlying the self-initiation of spontaneous behaviors. The establishment of a fundamental neural mechanism underlying apathy affords a key target for the development of novel therapeutics and cure strategies for affective alterations associated with HIV-1.

neuroscience↗

bioRxiv2021

Neurodevelopmental processes in the prefrontal cortex derailed by chronic HIV-1 viral protein exposure

Due to the widespread access to, and implementation of, combination antiretroviral therapy, individuals perinatally infected with human immunodeficiency virus type 1 (HIV-1) are living into adolescence and adulthood. Perinatally infected adolescents living with HIV-1 (pALHIV) are plagued by progressive, chronic neurocognitive impairments; the pathophysiological mechanisms underlying these deficits, however, remains understudied. A longitudinal experimental design from postnatal day (PD) 30 to PD 180 was utilized to establish the development of pyramidal neurons, and associated dendritic spines, from layers II-III of the medial prefrontal cortex (mPFC). Three putative neuroinflammatory markers (i.e., IL-1{beta}, IL-6, and TNF-) were evaluated early in development (i.e., PD 30) as a potential mechanism underlying synaptic dysfunction in the mPFC. Constitutive expression of HIV-1 viral proteins induced prominent neurodevelopmental alterations, independent of biological sex, in pyramidal neurons from layers II-III of the mPFC. Specifically, HIV-1 transgenic rats exhibited prominent deficits in dendritic and synaptic pruning, a developmental decrease in synaptic connectivity, and an age-related decline in synaptic efficacy. Examination of dendritic spine morphology revealed an age-related population shift towards a more immature dendritic spine phenotype in HIV-1 transgenic animals. There was no compelling evidence for neuroinflammation in the mPFC during early development. Understanding the neural mechanisms underlying chronic neurocognitive impairments in pALHIV may afford a key target for innovative therapeutics and cure strategies; an urgent need given the growing population of pALHIV.

neuroscience↗

bioRxiv2021

Chronic SSRI treatment reverses HIV-1 protein-mediated synaptodendritic damage

HIV-1 infection affects approximately 37 million individuals and approximately 50% of seropositive individuals will develop symptoms of clinical depression and apathy. Dysfunctions of both serotonergic and dopaminergic neurotransmission have been implicated in the pathogenesis of motivational alterations. The present study evaluated the efficacy of a SSRI (escitalopram) in the HIV-1 transgenic (Tg) rat. Behavioral, neurochemical, and neuroanatomical outcomes with respect to HIV-1 and sex were evaluated to determine the efficacy of chronic escitalopram treatment. Escitalopram treatment restored function in each of the behavioral tasks that were sensitive to HIV-1 induced impairments. Further, escitalopram treatment restored HIV-1-mediated synaptodendritic damage in the nucleus accumbens; treatment with escitalopram significantly increased dendritic proliferation in HIV-1 Tg rats. However, restoration did not consistently occur with the neurochemical analysis in the HIV-1 rat. Taken together, these results suggest a role for SSRI therapies in repairing long-term HIV-1 protein-mediated neuronal damage and restoring function.

neuroscience↗

bioRxiv2020

Valid statistical approaches for clustered data: A Monte Carlo simulation study

The translation of preclinical studies to human applications is associated with a high failure rate, which may be exacerbated by limited training in experimental design and statistical analysis. Nested experimental designs, which occur when data have a multilevel structure (e.g., in vitro: cells within a culture dish; in vivo: rats within a litter), often violate the independent observation assumption underlying many traditional statistical techniques. Although previous studies have empirically evaluated the analytic challenges associated with multilevel data, existing work has not focused on key parameters and design components typically observed in preclinical research. To address this knowledge gap, a Monte Carlo simulation study was conducted to systematically assess the effects of inappropriately modeling multilevel data via a fixed effects ANOVA in studies with sparse observations, no between group comparison within a single cluster, and interactive effects. Simulation results revealed a dramatic increase in the probability of type 1 error and relative bias of the standard error as the number of level-1 (e.g., cells; rats) units per cell increased in the fixed effects ANOVA; these effects were largely attenuated when the nesting was appropriately accounted for via a random effects ANOVA. Thus, failure to account for a nested experimental design may lead to reproducibility challenges and inaccurate conclusions. Appropriately accounting for multilevel data, however, may enhance statistical reliability, thereby leading to improvements in translatability. Valid analytic strategies are provided for a variety of design scenarios.

scientific communication and education↗