Biology subjects

Montilla-Perez, P.

Publications and source records attributed to Montilla-Perez, P..

7 recordsLinked to original sources

bioRxiv2025

The development of FEDUPP: Feeding Experimentation Device Users Processing Package to Assess Learning and Cognitive Flexibility

Cognitive flexibility, the ability to adapt behavior in response to changing contingencies, is a key component of adaptive decision-making and is impaired in multiple neuropsychiatric disorders. Traditional rodent assays of cognitive flexibility are conducted in experimenter-controlled sessions in restrictive environments, limiting ecological validity and temporal resolution. Here, we developed a fully automated, home-cage paradigm using the Feeding Experimentation Device 3 (FED3) and a companion open-source analysis pipeline, the Feeding Experimentation Device Users Processing Package (FEDUPP), to assess learning and cognitive flexibility with minimal experimenter intervention. The paradigm combines a single-day fixed-ratio 1 (FR1) task with a multi-day, reversal learning task in which active port assignment switches every 25 pellets collected. FEDUPP implements multi-scale learning metrics, including overall accuracy, an 80% accuracy milestone, and a machine learning-based classification of meal accuracy to capture motivated, goal-directed feeding. In wild-type mice, the paradigm detected rapid FR1 acquisition and progressive within-block adaptation during reversal. Application to mice with dorsal hippocampal knockdown of the scaffolding protein CASK revealed faster FR1 acquisition and higher accuracy than controls but a delayed onset of the first accurate meal after reversal, suggesting a selective deficit in updating goal-directed feeding behavior. These findings demonstrate that FEDUPP enables high-resolution, continuous assessment of learning and cognitive flexibility in ethologically relevant settings, and that meal-based accuracy provides a sensitive metric for detecting subtle flexibility impairments not captured by traditional measures.

animal behavior and cognition↗

bioRxiv2022

Reelin deficiency exacerbates cocaine-induced hyperlocomotion by enhancing neuronal activity in the dorsomedial striatum.

The Reln gene encodes for the extracellular glycoprotein Reelin, which regulates several brain functions from development to adulthood, including neuronal migration, dendritic growth and branching, and synapse formation and plasticity. Human studies have implicated Reelin signaling in several neurodevelopmental and psychiatric disorders. Mouse studies using the heterozygous Reeler (HR) mice have shown that reduced levels of Reln expression are associated with deficits in learning and memory and increased disinhibition. Although these traits are relevant to substance use disorders, the role of Reelin in cellular and behavioral responses to addictive drugs remains largely unknown. Here, we compared HR mice to wild-type (WT) littermate controls to investigate the contribution of Reelin signaling to the hyper-locomotor and rewarding effects of cocaine. After a single cocaine injection, HR mice showed enhanced cocaine-induced locomotor activity compared to WT controls. After repeated injections of cocaine, Reelin deficiency also led to increased cocaine-induced locomotor sensitization, which persisted after withdrawal. In contrast, Reelin deficiency did not affect the rewarding effects of cocaine measured in the conditioned place preference assay. The elevated cocaine-induced hyper-locomotion in HR mice resulted in increased Fos expression in the dorsal medial striatum (DMS) compared to WT. Lastly, we found that Reln was highly co-expressed with the Drd1 gene, which encodes for the dopamine receptor D1, in the DMS. These findings demonstrated that Reelin signaling contributes to the locomotory effects of cocaine and improved our understanding of the neurobiological mechanisms underlying the cellular and behavioral effects of cocaine.

neuroscience↗

bioRxiv2022

Nuclear Receptor 5A2 Regulation of Agrp underlies Olanzapine-induced Hyperphagia

Summary/AbstractAntipsychotic (AP) drugs are highly efficacious treatments for psychiatric disorders, but a serious side effect of their use is excessive weight gain and subsequent development of metabolic disease. Increased food intake is the underlying driver of AP-induced weight gain, although the underlying mechanisms remain unknown. In previous studies, we identified hypothalamic genes whose expression level was altered following APs-induced hyperphagia. Among these genes, the orexigenic peptide Agrp and the transcription factor nuclear receptor subfamily 5 group A member 2 (Nr5a2) were two of the most significantly upregulated genes by APs. NR5a2 is broadly expressed throughout the body, but little is known about its role in the brain. In this study, we investigated the role of hypothalamic NR5a2 in AP-induced hyperphagia and weight gain. In hypothalamic cell lines, OLZ treatment resulted in a dose-dependent increase in gene expression of NR5a2 and Agrp. In mice, administration of a specific Nr5a2 inhibitor decreased olanzapine-induced hyperphagia and weight gain, while knockdown of Nr5a2 in the arcuate nucleus (ARC) partially reversed olanzapine-induced hyperphagia. Chromatin-immunoprecipitation-PCR studies showed for the first time that NR5a2 directly binds to the Agrp promoter region. In addition, in situ hybridization studies confirm that NR5a2 and Agrp are co-localized in a subset of cells in the arcuate nucleus. In summary, we identify Nr5a2 as a key mechanistic driver of AP-induced food intake and these findings can be used to inform future clinical development of APs that do not activate hyperphagia and weight gain.

physiology↗

bioRxiv2022

GR-regulated enhancers play a central role in the gene regulatory networks underlying drug addiction

Substance abuse and addiction represent a significant public health problem that impacts multiple dimensions of society, including healthcare, the economy, and the workforce. In 2021, over 100,000 drug overdose deaths were reported in the US, with an alarming increase in fatalities related to opioids and psychostimulants. Understanding the fundamental gene regulatory mechanisms underlying addiction and related behaviors could facilitate more effective treatments. To explore how repeated drug exposure alters gene regulatory networks in the brain, we combined capped small (cs)RNA-seq, which accurately captures nascent-like initiating transcripts from total RNA, with Hi-C and single nuclei (sn)ATAC-seq. We profiled initiating transcripts in two addiction-related brain regions, the prefrontal cortex (PFC) and the nucleus accumbens (NAc), from rats that were never exposed to drugs or were subjected to prolonged abstinence after oxycodone or cocaine intravenous self-administration (IVSA). Interrogating over 100,000 active transcription start regions (TSRs) revealed that most TSRs had hallmarks of bonafide enhancers and highlighted the KLF/SP1, RFX, and AP1 transcription factors families as central to establishing brain-specific gene regulatory programs. Analysis of rats with addiction-like behaviors versus controls identified addiction-associated repression of transcription at regulatory enhancers recognized by nuclear receptor subfamily 3 group C (NR3C) factors, which include glucocorticoid receptors. Cell-type deconvolution analysis using snATAC-seq uncovered a potential role of glial cells in driving the gene regulatory programs associated with addiction-related phenotypes. These findings highlight the power of advanced transcriptomics methods to provide insight into how addiction perturbs gene regulatory programs in the brain.

neuroscience↗

bioRxiv2021

Chronic adolescent exposure to cannabis in mice leads to long-term sex-biased changes in gene expression networks across brain regions

During adolescence, frequent and heavy cannabis use can lead to serious adverse health effects and cannabis use disorders (CUD). Rodent models of adolescent exposure to the main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), mimic the behavioral alterations observed in adolescent users. However, the underlying molecular mechanisms remain largely unknown. Here, we treated female and male mice with high doses of THC during early adolescence and assessed their memory and social behaviors in late adolescence. We then profiled the transcriptome of five brain regions involved in cognitive and addiction-related processes. We applied gene coexpression network analysis and identified gene coexpression modules, termed cognitive modules, that simultaneously correlated with THC treatment and memory traits reduced by THC. The cognitive modules were related to endocannabinoid signaling in the female dorsal medial striatum, inflammation in the female ventral tegmental area, and synaptic transmission in the male nucleus accumbens. Moreover, cross-brain region module-module interaction networks uncovered intra- and inter-region molecular circuitries influenced by THC. Lastly, we identified key driver genes of gene networks associated with THC in mice and genetic susceptibility to CUD in humans. This analysis revealed a common regulatory mechanism linked to CUD vulnerability in the nucleus accumbens of females and males, which shared four key drivers (Hapln4, Kcnc1, Elav12, Zcchc12). These genes regulate transcriptional subnetworks implicated in addiction processes, synaptic transmission, brain development, and lipid metabolism. Our study provides novel insights into disease mechanisms regulated by adolescent exposure to THC in a sex- and brain region-specific manner.

neuroscience↗

bioRxiv2020

Functional validation of a finding from a mouse genome-wide association study demonstrates that a mutant allele of Azi2 alters sensitivity to methamphetamine

Methamphetamine is a widely abused psychostimulant. In a previous genome-wide association study (GWAS), we identified a locus that influenced the stimulant response to methamphetamine. That locus was also an eQTL for the gene Azi2. Based on those findings, we hypothesized that heritable differences in the expression of Azi2 were causally related to the differential response to methamphetamine. In this study, we created a mutant Azi2 allele that caused lower Azi2 expression and enhanced the locomotor response to methamphetamine; however, based on the GWAS findings, we had expected lower Azi2 to decrease rather than increase the stimulant response to methamphetamine. We then sought to explore the mechanism by which Azi2 influenced methamphetamine sensitivity. A recent publication had reported that the 3UTR of Azi2 mRNA downregulates the expression of Slc6a3, which encodes the dopamine transporter (DAT), which is a key target of methamphetamine. We evaluated the relationship between Azi2/Azi2 3UTR and Slc6a3 expression in the VTA in the mutant Azi2 mice and in a new cohort of CFW mice. We did not observe any correlation between Azi2 and Slc6a3 in the VTA in either cohort. However, RNA sequencing confirmed that the Azi2 mutation altered Azi2 expression and also revealed a number of potentially important genes and pathways that were regulated by Azi2, including the metabotropic glutamate receptor group III pathway and nicotinic acetylcholine receptor signaling pathway. Our results support a role for Azi2 in methamphetamine sensitivity; however, the exact mechanism does not appear to involve regulation of Slc6a3 and thus remains unknown.

animal behavior and cognition↗

bioRxiv2020

Reelin deficiency contributes to long-term behavioral abnormalities induced by chronic adolescent exposure to Δ9-tetrahydrocannabinol in mice

Heavy and frequent use of cannabis during adolescence increases the risk of developing psychiatric disorders. However, the neurobiological mechanisms underlying this vulnerability remain largely unknown. Here, we explore whether adolescent vulnerability to long-term behavioral effects of cannabis is modulated by Reelin, a gene implicated in the development of the brain and of psychiatric disorders. To this aim, heterozygous Reeler (HR) mice, that express reduced level of Reelin, were chronically exposed during adolescence to high doses (10mg/kg) of {Delta}9-tetrahydrocannabinol (THC), a major psychoactive component of cannabis. Mice were tested in early adulthood with multiple behavioral assays, including working memory, social interaction, locomotor activity, anxiety-like responses, stress reactivity, and pre-pulse inhibition. Compared to wild-type (WT), HR mice treated with THC showed impaired social behaviors, elevated disinhibitory phenotypes and increased responsiveness to aversive situations, in a sex-specific manner. Independent of THC exposure, HR mice also spent more time exploring unfamiliar objects, indicating that Reelin modulates novelty seeking behavior. To identify the neuronal ensemble underlying this elevated novelty seeking in HR mice, we mapped the regional brain expression of the immediate early gene, Fos, in mice exposed to novel objects. HR mice exhibited reduced neuronal activation in the lateral septum, a subcortical brain structure implicated in emotions, cognition and reward processes. Overall, these findings show that (1) Reelin deficiency influences behavioral abnormalities caused by heavy consumption of THC during adolescence, and (2) that Reelin plays a role in the neurobiological mechanisms underlying disinhibitory behaviors, such as novelty seeking. Significant StatementThe link between cannabis abuse and the development psychiatric disorders, especially in adolescents, makes understanding the neurobiological mechanisms underlying cannabis effects on the brain a significant biomedical problem. Reelin is a key signaling molecule in the development of the adolescent brain and of psychiatric disorders, but its role in modulating the behavioral changes induced by cannabis remain unknown. Here, we report an interaction between Reelin deficiency and chronic adolescent exposure to THC, a major psychoactive component of cannabis. This interaction led to cognitive deficits, disinhibitory behaviors and altered emotional reactivity in mice, in a sex-specific manner. These experiments are the first to establish a link between Reelin signaling and the endocannabinoid system targeted by THC.

neuroscience↗