Biology subjects

Joffe, M. E.

Publications and source records attributed to Joffe, M. E..

9 recordsLinked to original sources

bioRxiv2026

Sex differences in cell type-specific transcriptional programs and GPCR signaling in the human subgenual anterior cingulate cortex

Psychiatric conditions show marked sex differences in disease onset, symptom presentation, and response to treatments. Understanding how sex differences manifest across molecularly distinct neuronal populations in individuals without psychiatric conditions may help explain sex-dependent variation in neural circuit function and treatment response. Here, we examined molecularly distinct cell types within the subgenual anterior cingulate cortex (sgACC) of non-psychiatric subjects. Using RNA sequencing data previously generated from laser-capture microdissected neurons, we investigated sex differences in gene expression and co-expression networks in excitatory pyramidal neurons (layers 2/3 and 5/6) and somatostatin (SST)-, parvalbumin (PVALB)-, and vasoactive intestinal peptide (VIP)-expressing inhibitory interneurons (N=10 males, 9 females). We identified sex differences in transcriptomic profiles, biological pathways, and co-expression network connectivity. PVALB cells showed stronger overall female transcriptional enrichment, while SST cells exhibited male-enriched transcriptional signatures. Weighted gene co-expression network analysis identified PVALB and SST modules more connected in males and females, respectively, which included hub genes involved in immune, extracellular matrix, and bioenergetic processes. Since G protein-coupled receptors (GPCRs) are viable therapeutic targets, we examined sex differences in GPCR transcripts. Across all GPCR-cell-type combinations, CHRM2 in PVALB cells showed the second strongest sex difference (enriched in females). To test the functional relevance of this difference, we used patch-clamp electrophysiology in mouse prefrontal cortex. M2 receptor activation increased maximal firing rates in PVALB cells from female but not male mice. Collectively, our findings demonstrate cell type-specific sex differences in the sgACC corresponding to functional differences in neuromodulator signaling, with potential implications for treatment response.

neuroscience↗

bioRxiv2026

Voluntary oral fentanyl intake produces dose- and sex-dependent physical dependence in mice without overt affective disturbances

The ongoing opioid epidemic underscores the need for scalable and translational preclinical models of voluntary opioid intake and dependence. We therefore sought to establish and validate a voluntary two-bottle choice drinking-in-the-dark (DID) model of oral opioid intake in mice and to determine relationships between experimental parameters and behaviors during and after withdrawal. Male and female C57BL/6J mice were given daily access to two bottles during the dark phase for 24 drinking sessions over 5 weeks. Control mice received two bottles containing water. Experimental mice received one water bottle and one bottle containing oxycodone (0.1-1 mg/mL) or fentanyl (10-100 {micro}g/mL) under varying session durations and concentrations. On the final day, physical dependence was assessed using naloxone-precipitated withdrawal and then a behavioral battery to assess negative affect was performed in the following week. Mice voluntarily consumed both oxycodone and fentanyl without taste adulteration and maintained drug preference across most concentrations. Oxycodone intake produced minimal withdrawal symptoms. In contrast, fentanyl intake resulted in naloxone-precipitated withdrawal that was modulated by session duration and concentration. Four-hour sessions produced stronger withdrawal than two-hour sessions at equivalent concentrations. Escalating high-concentration fentanyl exposure revealed emerging sex differences, with females exhibiting greater intake and withdrawal at higher concentrations. Affective behavioral assays following withdrawal revealed minimal persistent alterations in any cohort. These findings establish key parameters for a scalable voluntary fentanyl model that produces dose- and session-dependent physical dependence in male and female mice. This paradigm provides a cost-effective and straightforward platform for future investigations of opioid use and dependence.

neuroscience↗

bioRxiv2026

Validation of an oral self-administration model of xylazine use in mice

Xylazine is a pervasive adulterant in clandestine opioid supplies. This trend is troubling, as xylazine carries its own acute side effects and its long-term cognitive and motivational effects are not known. Thus, we developed and validated a model of oral xylazine self-administration that is conducive to polysubstance studies and can easily be implemented in animal research labs. Mice underwent 4-hour drinking sessions where their only source of drinking water was adulterated with xylazine (10-1000{micro}g/mL). Oral bioavailability and brain penetrance were validated using mass spectrometry on brain and plasma samples collected after a drinking session. Male and female mice decreased fluid intake at high concentrations of xylazine, with male mice consuming less than female mice at intermediate concentrations (100 and 300{micro}g/mL). Female mice had decreased locomotion following drinking sessions at 100, 300, and 1000{micro}g/mL. After a 4-hour drinking session, all mice received brain xylazine concentrations that are above the Ki (affinity) and EC50 (potency) of several known binding targets of xylazine. We then performed a three-bottle choice experiment where mice had the option of drinking from water with xylazine, water with fentanyl, or plain water. In three-bottle choice, mice consumed less xylazine-containing water than fentanyl-containing or plain water. Our results indicate that xylazine is orally bioavailable in mice, that mice will readily drink xylazine to pharmacologically and behaviorally relevant doses, and that mice prefer consuming fentanyl and water over xylazine.

pharmacology and toxicology↗

bioRxiv2024

Mu and Delta Opioid Receptors Modulate Inhibition within the Prefrontal Cortex through Dissociable Cellular and Molecular Mechanisms

Aberrant signaling within cortical inhibitory microcircuits has been identified as a common signature of neuropsychiatric disorders. Interneuron (IN) activity is precisely regulated by neuromodulatory systems that evoke widespread changes in synaptic transmission and principal cell output. Cortical interneurons express high levels of Mu and Delta opioid receptors (MOR and DOR), positioning opioid signaling as a critical regulator of inhibitory transmission. However, we lack a complete understanding of how MOR and DOR regulate prefrontal cortex (PFC) microcircuitry. Here, we combine whole-cell patch-clamp electrophysiology, optogenetics, and viral tools to provide an extensive characterization MOR and DOR regulation of inhibitory transmission. We show that DOR activation is more effective at suppressing spontaneous inhibitory transmission in the prelimbic PFC, while MOR causes a greater acute suppression of electrically-evoked GABA release. Cell type-specific optogenetics revealed that MOR and DOR differentially regulate inhibitory transmission from parvalbumin, somatostatin, cholecystokinin, and vasoactive intestinal peptide-expressing INs. Finally, we demonstrate that DOR regulates inhibitory transmission through pre- and postsynaptic modifications to IN physiology, whereas MOR function is predominantly observed in somato-dendritic or presynaptic compartments depending on cell type. Significance StatementThe endogenous opioid system regulates behaviors that rely on prefrontal cortex (PFC) function. Previous studies have described Mu and Delta opioid receptor expression within cortical GABAergic interneurons, but a detailed understanding of how opioids regulate different interneuron subtypes and cortical microcircuits has not been reported. We use whole-cell patch-clamp electrophysiology, genetically engineered mice, and optogenetics to assess MOR and DOR regulation of PFC inhibitory transmission, demonstrating that MOR and DOR inhibition of interneurons display qualitative and quantitative variation across GABAergic circuits within mouse prelimbic PFC.

neuroscience↗

bioRxiv2023

Parvalbumin interneuron mGlu5 receptors govern sex differences in prefrontal cortex physiology and binge drinking

Despite established sex differences in the prevalence and presentation of psychiatric disorders, little is known about the cellular and synaptic mechanisms that guide these differences under basal conditions. Proper function of the prefrontal cortex (PFC) is essential for the top-down regulation of motivated behaviors. Activity of the PFC is tightly controlled by parvalbumin-expressing interneurons (PV-INs), a key subpopulation of fast-spiking GABAergic cells that regulate cortical excitability through direct innervations onto the perisomatic regions of nearby pyramidal cells. Recent rodent studies have identified notable sex differences in PV-IN activity and adaptations to experiences such as binge drinking. Here, we investigated the cellular and molecular mechanisms that underlie sex-specific regulation of PFC PV-IN function. Using whole-cell patch clamp electrophysiology and selective pharmacology, we report that PV-INs from female mice are more excitable than those from males. Moreover, we find that mGlu1 and mGlu5 metabotropic glutamate receptors regulate cell excitability, excitatory drive, and endocannabinoid signaling at PFC PV-INs in a sex-dependent manner. Genetic deletion of mGlu5 receptors from PV-expressing cells abrogates all sex differences observed in PV-IN membrane and synaptic physiology. Lastly, we report that female, but not male, PV-mGlu5-/- mice exhibit decreased voluntary drinking on an intermittent access schedule, which could be related to changes in ethanols stimulant properties. Importantly, these studies identify mGlu1 and mGlu5 receptors as candidate signaling molecules involved in sex differences in PV-IN activity and behaviors relevant for alcohol use.

neuroscience↗

bioRxiv2023

Acute alcohol and chronic drinking bidirectionally regulate the excitability of prefrontal cortex vasoactive intestinal peptide interneurons

The prefrontal cortex (PFC) regulates drinking behaviors and affective changes following chronic alcohol use. PFC activity is dynamically modulated by local inhibitory interneurons (INs), which can be divided into non-overlapping groups with distinct functional roles. Within deeper layers of neocortex, INs that express either parvalbumin or somatostatin directly inhibit pyramidal cells. By contrast, the plurality of all remaining INs express vasoactive intestinal peptide (VIP), reside within superficial layers, and preferentially target other types of INs. While recent studies have described adaptations to PFC parvalbumin-INs and somatostatin-INs in alcohol use models, whether ethanol or drinking affect the physiology of PFC VIP-INs has not been reported. To address this gap, we used genetically engineered female and male mice to target VIP-INs in layers 1-3 of prelimbic PFC for whole-cell patch-clamp electrophysiology. We found that ethanol (20 mM, [~]0.09 BEC) application to PFC brain slices enhances VIP-IN excitability. We next examined effects following chronic drinking by providing mice with 4 weeks of intermittent access (IA) ethanol two-bottle choice in the home cage. In these studies, VIP-INs from female and male IA ethanol mice displayed reduced excitability relative to cells from water-only controls. Finally, we assessed whether these effects continue into abstinence. After 7-11 days without ethanol, the hypo-excitability of VIP-INs from male IA ethanol mice persisted, whereas cells from female IA ethanol mice were not different from their controls. Together, these findings illustrate that acute ethanol enhances VIP-IN excitability and suggest these cells undergo pronounced homeostatic changes following long-term drinking.

neuroscience↗

bioRxiv2022

Differences in self-reported benefits for student-artist versus faculty experiences in a virtual artist-in-residence program.

The value of science communication in engaging the public has been well established. While many new programs bridge the arts and sciences, conducting comprehensive examination of exiting art-science programs can produce more efficient training and program development guidance for improving visual communications in the sciences. Here, we recruited a variety of scientists and artists to collaborate in creating visual science communication products over three summers. Using survey data, we performed qualitative and quantitative analyses to define sources for negative and positive experiences and outcomes from the Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4) Artist-in-Residence (AiR) program. Further, we analyze responses from participants, student-artists and faculty, to specify areas for improvement and areas successful in producing a positive experience and outcome in an AiR program. We found that time and virtual delivery of the program could be modified to improve the experience. Additionally, we found that student participants had more positive responses about "learning something new" from the program than faculty members. However, the most surprising aspect of our analysis suggests that for both "way of thinking" and "science communication to the public or general audience," there may be more significant beneficial gains for faculty compared to students. We conclude this analysis with suggestions to enhance the benefits and outcomes of an AiR program and ways to minimize the difficulties, such as communication and collaboration, faced by participants and program designers.

scientific communication and education↗

bioRxiv2020

Activating mGlu3 metabotropic glutamate receptors rescues schizophrenia-like cognitive deficits through metaplastic adaptations within the hippocampus.

BackgroundPolymorphisms in GRM3, the gene encoding the mGlu3 metabotropic glutamate receptor, are associated with impaired cognition and neuropsychiatric disorders such as schizophrenia. Limited availability of selective genetic and molecular tools has hindered progress in developing a clear understanding of the mechanisms through which mGlu3 receptors regulate synaptic plasticity and cognition. MethodsWe examined associative learning in mice with trace fear conditioning, a hippocampal-dependent learning task disrupted in patients with schizophrenia. Underlying cellular mechanisms were assessed using ex vivo hippocampal slice preparations with selective pharmacological tools and selective genetic deletion of mGlu3 receptor expression in specific neuronal subpopulations. ResultsmGlu3 receptor activation enhanced trace fear conditioning and reversed deficits induced by subchronic phencyclidine. Mechanistic studies revealed that mGlu3 receptor activation induced metaplastic changes, biasing afferent stimulation to induce long-term potentiation through a mGlu5 receptor-dependent, endocannabinoid-mediated, disinhibitory mechanism. Selective genetic deletion of either mGlu3 or mGlu5 from hippocampal pyramidal cells eliminated effects of mGlu3 activation, revealing a novel mechanism by which mGlu3 and mGlu5 interact to enhance cognitive function. ConclusionsThese data demonstrate that activation of mGlu3 receptors in hippocampal pyramidal cells enhances hippocampal-dependent cognition in control and impaired mice by inducing a novel form of metaplasticity to regulate circuit function - providing a clear mechanism through which genetic variation in GRM3 can contribute to cognitive deficits. Developing approaches to positively modulate mGlu3 receptor function represents an encouraging new avenue for treating cognitive disruption in schizophrenia and other psychiatric diseases.

pharmacology and toxicology↗

bioRxiv2020

Contrasting adaptations to synaptic physiology of prefrontal cortex interneuron subtypes in a mouse model of binge drinking

Alcohol use disorder (AUD) affects all sexes, however women who develop AUD may be particularly susceptible to cravings and other components of the disease. While many brain regions are involved in AUD etiology, proper function of the prefrontal cortex (PFC) is particularly important for top-down craving management and the moderation of drinking behaviors. Essential regulation of PFC output is provided by local inhibitory interneurons, yet the effects of chronic drinking on interneuron physiology remain poorly understood, particularly in female individuals. To address this gap, we generated fluorescent reporter transgenic mice to label the two major classes of interneuron in deep layer prelimbic PFC, based on expression of parvalbumin (PV-IN) or somatostatin (SST-IN). We then interrogated PV-IN and SST-IN membrane and synaptic physiology in a rodent model of binge drinking. Beginning in late adolescence, mice received 3-4 weeks of intermittent access (IA) ethanol. One day after the last drinking session, adaptations to PV-IN and SST-IN intrinsic physiology were observed in male mice but not in female mice. Furthermore, IA ethanol precipitated diametrically opposing changes to PV-IN synaptic physiology based on sex. IA ethanol decreased excitatory synaptic strength onto PV-INs from female mice and potentiated excitatory transmission onto PV-INs male mice. In contrast, decreased synaptic strength onto SST-INs was observed following IA ethanol in all groups of mice. Together, these findings illustrate novel sex differences in drinking-related PFC pathophysiology. Discovering means to restore PV-IN and SST-IN dysfunction following extended drinking provides opportunities for developing new treatments for all AUD patients.

neuroscience↗