Genomic description of acquired fluconazole- and echinocandin-resistance in patients with serial Candida glabrata isolates.

Candida glabrata is one of the most common causes of systemic candidiasis, often resistant to antifungal medications. To describe the genomic context of emerging resistance, we conducted a retrospective analysis of 82 serially collected isolates from 33 patients from population-based candidemia surveillance in the United States. We used whole-genome sequencing to determine the genetic relationships between isolates obtained from the same patient. Phylogenetic analysis demonstrated that isolates from 29 patients were clustered by patient. The median SNPs between isolates from the same patient was 30 (range: 7-96 SNPs), while unrelated strains infected four patients. Twenty-one isolates were resistant to echinocandins, and 24 were resistant to fluconazole. All echinocandin-resistant isolates carried a mutation either in the FKS1 or FKS2 HS1 region. Of the 24 fluconazole-resistant isolates, 17 (71%) had non-synonymous polymorphisms in the PDR1 gene, which were absent in susceptible isolates. In 11 patients, a genetically related resistant isolate was collected after recovering susceptible isolates, indicating in vivo acquisition of resistance. These findings allowed us to estimate the intra-host diversity of C. glabrata and propose an upper boundary of 96 SNPs for defining genetically related isolates, which can be used to assess donor-to-host transmission, nosocomial transmission, or acquired resistance. IMPORTANCE In our study, mutations associated to azole resistance and echinocandin resistance were detected in Candida glabrata isolates using a whole-genome sequence. C. glabrata is the second most common cause of candidemia in the United States, which rapidly acquires resistance to antifungals, in vitro and in vivo.

Cocaine-Induced Changes in Sperm Cdkn1a Methylation Are Associated with Cocaine Resistance in Male Offspring.

Paternal environmental perturbations can influence the physiology and behavior of offspring. For example, our previous work showed reduced cocaine reinforcement in male, but not female, progeny of rat sires that self-administered cocaine. The information transfer from sire to progeny may occur through epigenetic marks in sperm, encompassing alterations in small noncoding RNAs, including microRNAs (miRNAs) and/or DNA methylation. Here, no reliable changes in miRNAs in the sperm of cocaine- relative to saline-experienced sires were identified. In contrast, 272 differentially methylated regions were observed in sperm between these groups. Two hypomethylated promoter regions in the sperm of cocaine-experienced rats were upstream of cyclin-dependent kinase inhibitor 1a (Cdkn1a). Cdkn1a mRNA also was selectively increased in the NAc of cocaine-sired male (but not female) offspring. Cocaine self-administration also enhanced Cdkn1a expression in the accumbens of cocaine-sired rats. These results suggest that changes in Cdkn1a may play a role in the reduced cocaine reinforcing efficacy observed in cocaine-sired male rats. Introducing a 90 d delay between sire self-administration and breeding reversed both cocaine resistance and the increase in accumbens Cdkn1a mRNA in male offspring, indicating that cocaine-induced epigenetic modifications are eliminated with sperm turnover. Collectively, our results indicate that cocaine self-administration produces hypomethylation of Cdkn1a in sperm and a selective increase in the expression of this gene in the NAc of male offspring, which is associated with blunted cocaine reinforcement.SIGNIFICANCE STATEMENT The relatively new field of transgenerational epigenetics explores the effects of environmental perturbations on offspring behavior and physiology. Our prior work in rats indicated that male, but not female, progeny of sires that self-administered cocaine displayed reduced cocaine reinforcement. The information transfer from sire to progeny may occur through heritable epigenetic marks in sperm, including DNA methylation. The present findings revealed two hypomethylated promoter regions upstream of the Cdkn1a gene in sire sperm. Remarkably, Cdkn1a expression was selectively decreased in offspring NAc, a brain region that regulates cocaine reinforcement.

Paternal nicotine taking elicits heritable sex-specific phenotypes that are mediated by hippocampal Satb2.

Nicotine intake, whether through tobacco smoking or e-cigarettes, remains a global health concern. An emerging preclinical literature indicates that parental nicotine exposure produces behavioral, physiological, and molecular changes in subsequent generations. However, the heritable effects of voluntary parental nicotine taking are unknown. Here, we show increased acquisition of nicotine taking in male and female offspring of sires that self-administered nicotine. In contrast, self-administration of sucrose and cocaine were unaltered in male and female offspring suggesting that the intergenerational effects of paternal nicotine taking may be reinforcer specific. Further characterization revealed memory deficits and increased anxiety-like behaviors in drug-naive male, but not female, offspring of nicotine-experienced sires. Using an unbiased, genome-wide approach, we discovered that these phenotypes were associated with decreased expression of Satb2, a transcription factor known to play important roles in synaptic plasticity and memory formation, in the hippocampus of nicotine-sired male offspring. This effect was sex-specific as no changes in Satb2 expression were found in nicotine-sired female offspring. Finally, increasing Satb2 levels in the hippocampus prevented the escalation of nicotine intake and rescued the memory deficits associated with paternal nicotine taking in male offspring. Collectively, these findings indicate that paternal nicotine taking produces heritable sex-specific molecular changes that promote addiction-like phenotypes and memory impairments in male offspring.

Deep brain stimulation for psychostimulant use disorders.

Safe and effective therapeutics for psychostimulant use disorders remain elusive. Deep brain stimulation (DBS), which is FDA-approved for other indications, is a promising candidate for treating severe substance use disorders. We examine the clinical and preclinical evidence for DBS of the nucleus accumbens as a possible therapeutic option for cocaine and methamphetamine use disorders. Limitations of the literature to date, including the lack of females included in studies evaluating the efficacy of DBS, and new strategies to optimize brain stimulation approaches are also discussed.

GLP-1 receptor signaling in the laterodorsal tegmental nucleus attenuates cocaine seeking by activating GABAergic circuits that project to the VTA.

An emerging preclinical literature suggests that targeting central glucagon-like peptide-1 receptors (GLP-1Rs) may represent a novel approach to treating cocaine use disorder. However, the exact neural circuits and cell types that mediate the suppressive effects of GLP-1R agonists on cocaine-seeking behavior are largely unknown. The laterodorsal tegmental nucleus (LDTg) expresses GLP-1Rs and functions as a neuroanatomical hub connecting the nucleus tractus solitarius (NTS), the primary source of central GLP-1, with midbrain and forebrain nuclei known to regulate cocaine-seeking behavior. The goal of this study was to characterize the role of LDTg GLP-1R-expressing neurons and their projections to the ventral tegmental area (VTA) in the reinstatement of cocaine-seeking behavior, an animal model of relapse. Here, we showed that administration of the GLP-1R agonist exendin-4 (Ex-4) directly into the LDTg significantly attenuated cocaine seeking at a dose that did not affect sucrose seeking, ad libitum food intake, or body weight. In addition, our studies revealed that selectively activating NTS-to-LDTg circuits attenuated cocaine seeking via a GLP-1R-dependent mechanism. We also demonstrated, for the first time, that GLP-1Rs are expressed primarily on GABAergic neurons in the LDTg and that the efficacy of Ex-4 to reduce cocaine seeking depends, in part, on activation of LDTg-to-VTA GABAergic projections. Taken together, these studies identify a central mechanism by which Ex-4 attenuates cocaine seeking and highlight GABAergic GLP-1R-expressing circuits in the midbrain as important anti-craving pathways in regulating cocaine craving-induced relapse.

Impacts of lake breeze meteorology on ozone gradient observations along Lake Michigan Shorelines in Wisconsin.

Daytime onshore lake breezes are a critical factor controlling ozone abundance at coastal sites around Lake Michigan. Coastal counties along the western shore of Lake Michigan have historically observed high ozone episodes dating to the 1970s. We classified ozone episode days based on the extent or absence of the lake breeze (i.e., "inland", "near-shore" or "no" lake breeze) to establish a climatology of these events. This work demonstrated variable gradients in ozone abundances based on these different types of meteorology, with the sharpest ozone concentration gradients on days with a near-shore lake breeze. On 76-82% of days in which ozone reached 70 ppb for at least 1 hour, a lake breeze was present. Evidence of ozone gradients from multiple observation platforms during the 2017 Lake Michigan Ozone Study (LMOS 2017) are shown for two days with different depths of lake breezes.

H3.3 Barcoding of Nucleus Accumbens Transcriptional Activity Identifies Novel Molecular Cascades Associated with Cocaine Self-administration in Mice.

Although numerous epigenetic modifications have been associated with addiction, little work has explored the turnover of histone variants. Uniquely, the H3.3 variant incorporates stably and preferentially into chromatin independently of DNA replication at active sites of transcription and transcription factor binding. Thus, genomic regions associated with H3.3-containing nucleosomes are particularly likely to be involved in plasticity, such as following repeated cocaine exposure. A recently developed mouse line expressing a neuron-specific hemagglutinin (HA)-tagged H3.3 protein was used to track transcriptionally active sites cumulatively across 19 d of cocaine self-administration. RNA-seq and H3.3-HA ChIP-seq analyses were performed on NAcc tissue collected following cocaine or food self-administration in male mice. RNA sequencing revealed five genes upregulated in cocaine relative to food self-administering mice: Fosb, Npas4, Vgf, Nptx2, and Pmepa1, which reflect known and novel cocaine plasticity-associated genes. Subsequent ChIP-seq analysis confirmed increased H3.3 aggregation at four of these five loci, thus validating H3.3 insertion as a marker of enhanced cocaine-induced transcription. Further motif recognition analysis of the ChIP-seq data showed that cocaine-associated differential H3.3 accumulation correlated with the presence of several transcription factor binding motifs, including RBPJ1, EGR1, and SOX4, suggesting that these are potentially important regulators of molecular cascades associated with cocaine-induced neuronal plasticity. Additional ontological analysis revealed differential H3.3 accumulation mainly near genes involved in neuronal differentiation and dendrite formation. These results establish the H3.3-HA transgenic mouse line as a compelling molecular barcoding tool to identify the cumulative effects of long-term environmental perturbations, such as exposure to drugs of abuse.SIGNIFICANCE STATEMENT Histone H3.3 is a core histone variant that is stably incorporated at active sites of transcription. We used a tagged version of H3.3 expressed exclusively in neurons to delineate active transcription sites following extended cocaine self-administration in mice. This approach revealed the cumulative list of genes expressed in response to cocaine taking over the course of several weeks. We combined this technique with RNA sequencing of tissue collected from the same animals 24 h after the last cocaine exposure. Comparing these datasets provided a full picture of genes that respond to chronic cocaine exposure in NAcc neurons. These studies revealed novel transcription factors that are likely involved in cocaine-induced plasticity and addiction-like behaviors.

Intratumoral delivery of tavokinogene telseplasmid yields systemic immune responses in metastatic melanoma patients.

BACKGROUND: Interleukin 12 (IL-12) is a pivotal regulator of innate and adaptive immunity. We conducted a prospective open-label, phase II clinical trial of electroporated plasmid IL-12 in advanced melanoma patients (NCT01502293). PATIENTS AND METHODS: Patients with stage III/IV melanoma were treated intratumorally with plasmid encoding IL-12 (tavokinogene telseplasmid; tavo), 0.5 mg/ml followed by electroporation (six pulses, 1500 V/cm) on days 1, 5, and 8 every 90 days in the main study and additional patients were treated in two alternative schedule exploration cohorts. Correlative analyses for programmed death-ligand 1 (PD-L1), flow cytometry to assess changes in immune cell subsets, and analysis of immune-related gene expression were carried out on pre- and post-treatment samples from study patients, as well as from additional patients treated during exploration of additional dosing schedules beyond the pre-specified protocol dosing schedule. Response was measured by study-specific criteria to maximize detection of latent and potentially transient immune responses in patients with multiple skin lesions and toxicities were graded by the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v4.0). RESULTS: The objective overall response rate was 35.7% in the main study (29.8% in all cohorts), with a complete response rate of 17.9% (10.6% in all cohorts). The median progression-free survival in the main study was 3.7 months while the median overall survival was not reached at a median follow up of 29.7 months. A total of 46% of patients in all cohorts with uninjected lesions experienced regression of at least one of these lesions and 25% had a net regression of all untreated lesions. Transcriptomic and immunohistochemistry analysis showed that immune activation and co-stimulatory transcripts were up-regulated but there was also increased adaptive immune resistance. CONCLUSIONS: Intratumoral Tavo was well tolerated and led to systemic immune responses in advanced melanoma patients. While tumor regression and increased immune infiltration were observed in treated as well as untreated/distal lesions, adaptive immune resistance limited the response.

Impaired cocaine-induced behavioral plasticity in the male offspring of cocaine-experienced sires.

Our previous work indicated that male, but not female, offspring of cocaine-experienced sires display blunted cocaine self-administration. We extended this line of investigation to examine behavioral sensitization, a commonly used model of cocaine-induced behavioral and neuronal plasticity. Results indicated that male, but not female, offspring of cocaine-taking sires showed deficits in the ability of repeated systemic cocaine injections to induce augmented locomotor activity. The reduced cocaine sensitization phenotype in male progeny was associated with changes in histone post-translational modifications, epigenetic processes that regulate gene expression by controlling the accessibility of genes to transcriptional machinery, in the nucleus accumbens of first-generation male progeny. Thus, five histone post-translational modifications were significantly altered in the male progeny of cocaine-exposed sires. In contrast, self-administration of nicotine was unaltered in male and female offspring suggesting that the intergenerational effects of paternal cocaine taking may be drug-specific. Interestingly, the reduced sensitivity to cocaine previously observed in the male offspring of cocaine-taking sires dissipated in the grand-offspring. Both male and female grand-progeny of cocaine-exposed sires showed unaltered cocaine-induced behavioral sensitization and cocaine self-administration. Taken together, these findings indicate that paternal cocaine taking produces changes in multiple cocaine addiction-related behaviors in male progeny, which do not persist beyond the first generation of offspring. Moreover, the altered sensitivity to cocaine in first-generation male progeny of cocaine-sired male offspring was associated with epigenetic modifications in the nucleus accumbens, a nucleus that plays a critical role in cocaine-associated behavioral plasticity.

Improving therapeutic efficacy of IL-12 intratumoral gene electrotransfer through novel plasmid design and modified parameters.

The use of immunomodulatory cytokines has been shown effective in regressing a wide range of tumors. However, systemic delivery of recombinant cytokines results in serious, potentially life-threatening, adverse effects. By contrast, nucleic acid transfer via electroporation (EP) is a safe and effective method of delivering plasmid-encoded cytokines to tumors. Intratumoral delivery of IL-12 plasmid DNA by electroporation (IT-pIL12-EP) produced objective response rates in Phase 2 clinical trials in metastatic melanoma. However, only 17.9% of patients receiving IT-pIL12-EP show a complete therapeutic response. Here, we sought to improve the antitumor efficacy of our clinical IT-pIL12-EP plasmid electroporation platform. We evaluated multiple plasmid designs for IL-12 expression. IL-12 expression from a plasmid incorporating a picornavirus-derived co-translational P2A site was the most effective in expressing IL-12p70. In addition, modifying the electroporation parameters improved transfection efficiency and expression of plasmid-derived IL-12p70, as well as its downstream effector IFN-γ in vivo. Finally, using a murine melanoma model that is representative of the intended target patient population, we show that combining modified electroporation conditions with the pIL12-P2A plasmid expression enhances the systemic antitumor response. These improvements to the IT-pIL12-EP platform may improve patient clinical response rates and survival when translated to clinical trials.

HIV Protease Inhibitors Alter Amyloid Precursor Protein Processing via ß-Site Amyloid Precursor Protein Cleaving Enzyme-1 Translational Up-Regulation.

Mounting evidence implicates antiretroviral (ARV) drugs as potential contributors to the persistence and evolution of clinical and pathological presentation of HIV-associated neurocognitive disorders in the post-ARV era. Based on their ability to induce endoplasmic reticulum (ER) stress in various cell types, we hypothesized that ARV-mediated ER stress in the central nervous system resulted in chronic dysregulation of the unfolded protein response and altered amyloid precursor protein (APP) processing. We used in vitro and in vivo models to show that HIV protease inhibitor (PI) class ARVs induced neuronal damage and ER stress, leading to PKR-like ER kinase-dependent phosphorylation of the eukaryotic translation initiation factor 2α and enhanced translation of ß-site APP cleaving enzyme-1 (BACE1). In addition, PIs induced ß-amyloid production, indicative of increased BACE1-mediated APP processing, in rodent neuroglial cultures and human APP-expressing Chinese hamster ovary cells. Inhibition of BACE1 activity protected against neuronal damage. Finally, ARVs administered to mice and SIV-infected macaques resulted in neuronal damage and BACE1 up-regulation in the central nervous system. These findings implicate a subset of PIs as potential mediators of neurodegeneration in HIV-associated neurocognitive disorders.

Paternal cocaine taking elicits epigenetic remodeling and memory deficits in male progeny.

Paternal environmental perturbations including exposure to drugs of abuse can produce profound effects on the physiology and behavior of offspring via epigenetic modifications. Here we show that adult drug-naive male offspring of cocaine-exposed sires have memory formation deficits and associated reductions in NMDA receptor-mediated hippocampal synaptic plasticity. Reduced levels of the endogenous NMDA receptor co-agonist d-serine were accompanied by increased expression of the d-serine degrading enzyme d-amino acid oxidase (Dao1) in the hippocampus of cocaine-sired male progeny. Increased Dao1 transcription was associated with enrichment of permissive epigenetic marks on histone proteins in the hippocampus of male cocaine-sired progeny, some of which were enhanced near the Dao1 locus. Finally, hippocampal administration of d-serine reversed both the memory formation and synaptic plasticity deficits. Collectively, these results demonstrate that paternal cocaine exposure produces epigenetic remodeling in the hippocampus leading to NMDA receptor-dependent memory formation and synaptic plasticity impairments only in male progeny, which has significant implications for the male descendants of chronic cocaine users.

Paternal cocaine taking elicits epigenetic remodeling and memory deficits in male progeny.

This corrects the article DOI: 10.1038/mp.2017.8.

Tropospheric Emissions: Monitoring of Pollution (TEMPO).

TEMPO was selected in 2012 by NASA as the first Earth Venture Instrument, for launch between 2018 and 2021. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO observes from Mexico City, Cuba, and the Bahamas to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution (~2.1 km N/S×4.4 km E/W at 36.5°N, 100°W). TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry, as well as contributing to carbon cycle knowledge. Measurements are made hourly from geostationary (GEO) orbit, to capture the high variability present in the diurnal cycle of emissions and chemistry that are unobservable from current low-Earth orbit (LEO) satellites that measure once per day. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a commercial GEO host spacecraft to provide a modest cost mission that measures the spectra required to retrieve ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (H2CO), glyoxal (C2H2O2), bromine monoxide (BrO), IO (iodine monoxide),water vapor, aerosols, cloud parameters, ultraviolet radiation, and foliage properties. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides these near-real-time air quality products that will be made publicly available. TEMPO will launch at a prime time to be the North American component of the global geostationary constellation of pollution monitoring together with the European Sentinel-4 (S4) and Korean Geostationary Environment Monitoring Spectrometer (GEMS) instruments.

Frequency of endoscopic surveillance for Barrett's esophagus is influenced by health insurance status: results from a population-based analysis.

Factors that influence the frequency of surveillance endoscopy for nondysplastic Barrett's esophagus are not well understood. The objective of this study is to assess factors which influence the frequency of endoscopic surveillance for Barrett's esophagus, including health insurance/third-party payer status. Cases of nondysplastic Barrett's esophagus undergoing esophagogastroduodenoscopy with biopsy were identified using longitudinal data from the Healthcare Utilization Project database in 2005-2006 and followed through 2011. The threshold for appropriate surveillance utilization was defined as two to four surveillance esophagogastroduodenoscopies over a standardized 5-year period. Patients' insurance status was designated as either Medicare, Medicaid, private, or noninsured. 36,676 cases of nondysplastic Barrett's esophagus were identified. Among these, 4,632 patients (12.6%) underwent between two and four surveillance esophagogastroduodenoscopies in 5 years of follow-up versus 31,975 patients (87.3%) who underwent fewer than two esophagogastroduodenoscopies during follow-up. Multivariate analysis found that Barrett's patients insured through Medicaid (OR 1.273; 95% CI = 1.065-1.522) or without insurance (OR = 2.453; 95% CI = 1.67-3.603) were at increased likelihood of being under-surveilled. This study identified a difference in frequency of surveillance esophagogastroduodenoscopy for Barrett's esophagus by payer status. Patients without health insurance and those whose primary insurance was Medicaid were at increased odds for under-surveillance. These data suggest that a more robust system for tracking and ensuring longitudinal follow-up of patients with Barrett's esophagus, with attention to the uninsured and underinsured population, may be needed to ensure optimal surveillance.

ADAR2-dependent GluA2 editing regulates cocaine seeking.

Activation of AMPA receptors (AMPARs) in the nucleus accumbens is necessary for the reinstatement of cocaine-seeking behavior, an animal model of drug craving and relapse. AMPARs are tetrameric protein complexes that consist of GluA1-4 subunits, of which GluA2 imparts calcium permeability. Adenosine deaminase acting on RNA 2 (ADAR2) is a nuclear enzyme that is essential for editing GluA2 pre-mRNA at Q/R site 607. Unedited GluA2(Q) subunits form calcium-permeable AMPARs (CP-AMPARs), whereas edited GluA2(R) subunits form calcium-impermeable channels (CI-AMPARs). Emerging evidence suggests that the reinstatement of cocaine seeking is associated with increased synaptic expression of CP-AMPARs in the nucleus accumbens. However, the role of GluA2 Q/R site editing and ADAR2 in cocaine seeking is unclear. In the present study, we investigated the effects of forced cocaine abstinence on GluA2 Q/R site editing and ADAR2 expression in the nucleus accumbens. Our results demonstrate that 7 days of cocaine abstinence is associated with decreased GluA2 Q/R site editing and reduced ADAR2 expression in the accumbens shell, but not core, of cocaine-experienced rats compared with yoked saline controls. To examine the functional significance of ADAR2 and GluA2 Q/R site editing in cocaine seeking, we used viral-mediated gene delivery to overexpress ADAR2b in the accumbens shell. Increased ADAR2b expression in the shell attenuated cocaine priming-induced reinstatement of drug seeking and was associated with increased GluA2 Q/R site editing and surface expression of GluA2-containing AMPARs. Taken together, these findings support the novel hypothesis that an increased contribution of accumbens shell CP-AMPARs containing unedited GluA2(Q) promotes cocaine seeking. Therefore, CP-AMPARs containing unedited GluA2(Q) represent a novel target for cocaine addiction pharmacotherapies.

Interannual Variability in Baseline Ozone and Its Relationship to Surface Ozone in the Western U.S.

Baseline ozone refers to observed concentrations of tropospheric ozone at sites that have a negligible influence from local emissions. The Mount Bachelor Observatory (MBO) was established in 2004 to examine baseline air masses as they arrive to North America from the west. In May 2012, we observed an O3 increase of 2.0-8.5 ppbv in monthly average maximum daily 8-hour average O3 mixing ratio (MDA8 O3) at MBO and numerous other sites in the western U.S. compared to previous years. This shift in the O3 distribution had an impact on the number of exceedance days. We also observed a good correlation between daily MDA8 variations at MBO and at downwind sites. This suggests that under specific meteorological conditions, synoptic variation in O3 at MBO can be observed at other surface sites in the western U.S. At MBO, the elevated O3 concentrations in May 2012 are associated with low CO values and low water vapor values, consistent with transport from the upper troposphere/lower stratosphere (UT/LS). Furthermore, the Real-time Air Quality Modeling System (RAQMS) analyses indicate that a large flux of O3 from the UT/LS in May 2012 contributed to the observed enhanced O3 across the western U.S. Our results suggest that a network of mountaintop observations, LiDAR and satellite observations of O3 could provide key data on daily and interannual variations in baseline O3.

Enhanced anxiety in the male offspring of sires that self-administered cocaine.

We previously showed that paternal cocaine exposure reduced the reinforcing efficacy of cocaine in male offspring. Here, we sought to determine whether paternal cocaine experience could also influence anxiety levels in offspring. Male rats were allowed to self-administer cocaine (controls received saline passively) for 60 days and then were bred with naïve females. Measures of anxiety and cocaine-induced anxiogenic effects were assessed in the adult offspring. Cocaine-sired male offspring exhibited increased anxiety-like behaviors, as measured using the novelty-induced hypophagia and defensive burying tasks, relative to saline-sired males. In contrast, sire cocaine experience had no effect on anxiety-like behaviors in female offspring. When challenged with an anxiogenic (but not anorectic) dose of cocaine (2.5 mg/kg, i.p.), anxiety-like behavior was enhanced in all animals to an equal degree regardless of sire drug experience. Since anxiety and depression are often co-morbid, we also assessed measures of depressive-like behavior. Sire cocaine experience had no effect on depression-like behaviors, as measured by the forced swim task, among male offspring. In a separate group of naïve littermates, select neuronal correlates of anxiety were measured. Male offspring of cocaine-experienced sires showed increased mRNA and protein expression of corticotropin-releasing factor receptor 2 in the hippocampus. Together, these results indicate that cocaine-experienced sires produce male progeny that have increased baseline anxiety, which is unaltered by subsequent cocaine exposure.

Glucagon-like peptide-1 receptor activation in the nucleus accumbens core suppresses feeding by increasing glutamatergic AMPA/kainate signaling.

Glucagon-like peptide-1 receptor (GLP-1R) activation in the nucleus accumbens (NAc) core is pharmacologically and physiologically relevant for regulating palatable food intake. Here, we assess whether GLP-1R signaling in the NAc core of rats modulates GABAergic medium spiny neurons (MSNs) through presynaptic-glutamatergic and/or presynaptic-dopaminergic signaling to control feeding. First, ex vivo fast-scan cyclic voltammetry showed that the GLP-1R agonist exendin-4 (Ex-4) does not alter dopamine release in the NAc core. Instead, support for a glutamatergic mechanism was provided by ex vivo electrophysiological analyses showing that Ex-4 activates presynaptic GLP-1Rs in the NAc core to increase the activity of MSNs via a glutamatergic, AMPA/kainate receptor-mediated mechanism, indicated by increased mEPSC frequency and decreased paired pulse ratio in core MSNs. Only a small, direct excitatory effect on MSNs by Ex-4 was observed, suggesting that the contribution of postsynaptic GLP-1R to MSN activity is minimal. The behavioral relevance of the electrophysiological data was confirmed by the finding that intracore injection of the AMPA/kainate receptor antagonist CNQX attenuated the ability of NAc core GLP-1R activation by Ex-4 microinjection to suppress food intake and body weight gain; in contrast, intracore NMDA receptor blockade by AP-5 did not inhibit the energy balance effects of NAc core Ex-4. Together, these data provide evidence for a novel glutamatergic, but not dopaminergic, mechanism by which NAc core GLP-1Rs promote negative energy balance.