Chen X, Liu Z, Ma C, Ma L, Liu X.
PMID: - | DOI: 10.3389/fnbeh.2019.00110
Parvalbumin (PV) expressing GABAergic interneurons provide large source of GABA to spiny projection neurons (SPNs) in the striatum. However, the roles of PV+ interneurons in the regulation of SPNs in the ventral striatum and emotional states are largely unknown. Here, we investigated whether stimulation of ventral striatal (accumbal) PV+ interneurons would drive emotional valence in mice. We found that during conditioned place preference (CPP) training, activation of accumbal PV+ interneurons evoked place preference while suppressing them resulted in conditioned place aversion (CPA). Activation of PV+interneurons during place conditioning increased Fos expression in SPNs in the direct pathway (dSPNs) and impaired lithium chloride-induced CPA. Activation of dSPNs and SPNs in the indirect pathway (iSPNs) induced CPP and CPA, respectively; conversely, suppression of dSPNs or iSPNs induced CPA or CPP. In addition, activation or suppression of calretinin-expressing (CR) GABAergic interneurons did not induce place preference or aversion. These data suggest that PV+ interneurons can bidirectionally determine the emotional valence through their regulation of accumbal SPN activities and raise the possibility that manipulation of PV+ interneuron activity may have the potential to alter emotional valence and treat related mental disorders.
Prrx1b restricts fibrosis and promotes Nrg1-dependent cardiomyocyte proliferation during zebrafish heart regeneration
Development (Cambridge, England)
de Bakker, DEM;Bouwman, M;Dronkers, E;Simões, FC;Riley, PR;Goumans, MJ;Smits, AM;Bakkers, J;
PMID: 34486669 | DOI: 10.1242/dev.198937
Fibroblasts are activated to repair the heart following injury. Fibroblast activation in the mammalian heart leads to a permanent fibrotic scar that impairs cardiac function. In other organisms, like zebrafish, cardiac injury is followed by transient fibrosis and scar-free regeneration. The mechanisms that drive scarring versus scar-free regeneration are not well understood. Here we show that the homeo-box containing transcription factor Prrx1b is required for scar-free regeneration of the zebrafish heart as the loss of Prrx1b results in excessive fibrosis and impaired cardiomyocyte proliferation. Through lineage tracing and single-cell RNA-sequencing we find that Prrx1b is activated in epicardial-derived cells (EPDCs) where it restricts TGF-β ligand expression and collagen production. Furthermore, through combined in vitro experiments in human fetal EPDCs and in vivo rescue experiments in zebrafish, we conclude that Prrx1 stimulates Nrg1 expression and promotes cardiomyocyte proliferation. Collectively, these results indicate that Prrx1 is a key transcription factor that balances fibrosis and regeneration in the injured zebrafish heart.
The Journal of neuroscience : the official journal of the Society for Neuroscience
Feinberg, PA;Becker, SC;Chung, L;Ferrari, L;Stellwagen, D;Anaclet, C;Durán-Laforet, V;Faust, TE;Sumbria, RK;Schafer, DP;
PMID: 35790400 | DOI: 10.1523/JNEUROSCI.0601-22.2022
Interferon regulatory factor 8 (IRF8) is a transcription factor necessary for the maturation of microglia, as well as other peripheral immune cells. It also regulates the transition of microglia and other immune cells to a pro-inflammatory phenotype. Irf8 is also a known risk gene for multiple sclerosis and lupus and it has recently been shown to be downregulated in schizophrenia. While most studies have focused on IRF8-dependent regulation of immune cell function, little is known about how it impacts neural circuits. Here, we show by RNAseq from Irf8-/- male and female mouse brains that several genes involved in regulation of neural activity are dysregulated. We then show these molecular changes are reflected in heightened neural excitability and a profound increase in susceptibility to lethal seizures in male and female Irf8-/- mice. Finally, we identify that TNF-α is elevated specifically in microglia in the CNS and genetic or acute pharmacological blockade of TNF-α in the Irf8-/- central nervous system (CNS) rescued the seizure phenotype. These results provide important insights into the consequences of IRF8 signaling and TNF-α on neural circuits. Our data further suggest that neuronal function is impacted by loss of IRF8, a factor involved in neuropsychiatric and neurodegenerative diseases.SIGNIFICANCE STATEMENTHere, we identify a previously unknown and key role for Interferon regulator factor 8 (IRF8) in regulating neural excitability and seizures. We further determine these effects on neural circuits are through elevated TNF-α in the CNS. As IRF8 has most widely been studied in the context of regulating the development and inflammatory signaling in microglia and other immune cells, we have uncovered a novel function. Further, IRF8 is a risk gene for multiple sclerosis (MS) and lupus, IRF8 is dysregulated in schizophrenia, and elevated TNF-α has been identified in a multitude of neurological conditions. Thus, elucidating these IRF8 and TNF-α-dependent effects on brain circuit function have profound implications for understanding underlying, therapeutically-relevant mechanisms of disease.
J Neurosci. 2015 May 27;35(21):8232-44.
Li X, Rubio FJ, Zeric T, Bossert JM, Kambhampati S, Cates HM, Kennedy PJ, Liu QR, Cimbro R, Hope BT, Nestler EJ, Shaham Y.
PMID: 26016895 | DOI: 10.1038/jid.2015.200.
Cue-induced methamphetamine seeking progressively increases after withdrawal (incubation of methamphetamine craving), but the underlying mechanisms are largely unknown. We determined whether this incubation is associated with alterations in candidate genes in dorsal striatum (DS), a brain area implicated in cue- and context-induced drug relapse. We first measured mRNA expression of 24 candidate genes in whole DS extracts after short (2 d) or prolonged (1 month) withdrawal in rats following extended-access methamphetamine or saline (control condition) self-administration (9 h/d, 10 d). We found minimal changes. Next, using fluorescence-activated cell sorting, we compared gene expression in Fos-positive dorsal striatal neurons, which were activated during "incubated" cue-induced drug-seeking tests after prolonged withdrawal, with nonactivated Fos-negative neurons. We found significant increases in mRNA expression of immediate early genes (Arc, Egr1), Bdnf and its receptor (Trkb), glutamate receptor subunits (Gria1, Gria3, Grm1), and epigenetic enzymes (Hdac3, Hdac4, Hdac5, GLP, Dnmt3a, Kdm1a) in the Fos-positive neurons only. Using RNAscope to determine striatal subregion and cell-type specificity of the activated neurons, we measured colabeling of Fos with Drd1 and Drd2 in three DS subregions. Fos expression was neither subregion nor cell-type specific (52.5 and 39.2% of Fos expression colabeled with Drd1 and Drd2, respectively). Finally, we found that DS injections of SCH23390 (C17H18ClNO), a D1-family receptor antagonist known to block cue-induced Fos induction, decreased incubated cue-induced methamphetamine seeking after prolonged withdrawal. Results demonstrate a critical role of DS in incubation of methamphetamine craving and that this incubation is associated with selective gene-expression alterations in cue-activated D1- and D2-expressing DS neurons.
Ziminski J, Hessler S, Margetts-Smith G, Sieburg MC, Crombag HS, Koya E.
PMID: 28213443 | DOI: 10.1523/JNEUROSCI.3766-16.2017
Cues that predict the availability of food rewards influence motivational states and elicit food-seeking behaviors. If a cue no longer predicts food availability, animals may adapt accordingly by inhibiting food seeking responses. Sparsely activated sets of neurons, coined neuronal ensembles, have been shown to encode the strength of reward-cue associations. While alterations in intrinsic excitability have been shown to underlie many learning and memory processes, little is known about these properties specifically on cue-activated neuronal ensembles. We examined the activation patterns of cue-activated orbitofrontal cortex (OFC) and nucleus accumbens (NAc) shell ensembles using wild-type and Fos-GFP mice following appetitive conditioning with sucrose and extinction learning. We also investigated the neuronal excitability of recently activated, GFP+ neurons in these brain areas using whole-cell electrophysiology in brain slices. Exposure to a sucrose cue elicited activation of neurons in both the NAc shell and OFC. In the NAc shell, but not the OFC, these activated GFP+ neurons were more excitable than surrounding GFP- neurons. Following extinction, the number of neurons activated in both areas was reduced and activated ensembles in neither area exhibited altered excitability. These data suggest that learning-induced alterations in the intrinsic excitability of neuronal ensembles is regulated dynamically across different brain areas. Furthermore, we show that changes in associative strength modulate the excitability profile of activated ensembles in the NAc shell.SIGNIFICANCE STATEMENTSparsely distributed sets of neurons called 'neuronal ensembles' encode learned associations about food and cues predictive of its availability. Widespread changes in neuronal excitability have been observed in limbic brain areas after associative learning, but little is known about the excitability changes that occur specifically on neuronal ensembles that encode appetitive associations. Here we reveal that sucrose cue exposure recruited a more excitable ensemble in the nucleus accumbens, but not orbitofrontal cortex compared to their surrounding neurons. This excitability difference was not observed when the cue's salience was diminished following extinction learning. These novel data provide evidence that the intrinsic excitability of appetitive memory-encoding ensembles is differentially regulated across brain areas and dynamically adapts to changes in associative strength.
Eur J Neurosci. 2018 Oct 11.
Rubio FJ, Quintana-Feliciano R, Warren BL, Li X, Witonsky KFR, Soto Del Valle F, Selvam PV, Caprioli D, Venniro M, Bossert JM, Shaham Y, Hope BT.
PMID: 30307667 | DOI: 10.1111/ejn.14203
Many preclinical studies examined cue-induced relapse to heroin and cocaine seeking in animal models, but most of these studies examined only one drug at a time. In human addicts, however, polydrug use of cocaine and heroin is common. We used a polydrug self-administration relapse model in rats to determine similarities and differences in brain areas activated during cue-induced reinstatement of heroin and cocaine seeking. We trained rats to lever press for cocaine (1.0 mg/kg/infusion, 3-h/d, 18 d) or heroin (0.03 mg/kg/infusion) on alternating days (9 d for each drug); drug infusions were paired with either intermittent or continuous light cue. Next, the rats underwent extinction training followed by tests for cue-induced reinstatement where they were exposed to either heroin- or cocaine-associated cues. We observed cue-selective reinstatement of drug seeking: the heroin cue selectively reinstated heroin seeking and the cocaine cue selectively reinstated cocaine seeking. We used Fos immunohistochemistry to assess cue-induced neuronal activation in different subregions of the medial prefrontal cortex (mPFC), dorsal striatum (DS), nucleus accumbens (NAc), and amygdala. Fos expression results indicated that only the prelimbic cortex (PL) was activated by both heroin and cocaine cues; in contrast, no significant cue-induced neuronal activation was observed in other brain areas. RNA in situ hybridization indicated that the proportion of glutamatergic and GABAergic markers in PL Fos-expressing cells were similar for the heroin and cocaine cue-activated neurons. Overall the results indicate that PL may be a common brain area involved in both heroin and cocaine seeking during polydrug use.
Pharmacology Biochemistry and Behavior
Lewis MH, Rajpal H, Muehlmann AM.
PMID: - | DOI: 10.1016/j.pbb.2019.04.006
Repetitive behaviors are diagnostic for autism spectrum disorder (ASD) and commonly observed in other neurodevelopmental disorders. Currently, there are no effective pharmacological treatments for repetitive behavior in these clinical conditions. This is due to the lack of information about the specific neural circuitry that mediates the development and expression of repetitive behavior. Our previous work in mouse models has linked repetitive behavior to decreased activation of the subthalamic nucleus, a brain region in the indirect and hyperdirect pathways in the basal ganglia circuitry. The present experiments were designed to further test our hypothesis that pharmacological activation of the indirect pathway would reduce repetitive behavior. We used a combination of adenosine A1 and A2A receptor agonists that have been shown to alter the firing frequency of dorsal striatal neurons within the indirect pathway of the basal ganglia. This drug combination markedly and selectively reduced repetitive behavior in both male and female C58 mice over a six-hour period, an effect that required both A1 and A2A agonists as neither alone reduced repetitive behavior. The adenosine A1 and A2A receptor agonist combination also significantly increased the number of Fos transcripts and Fospositive cells in dorsal striatum. Fos induction was found in both direct and indirect pathway neurons suggesting that the drug combination restored the balance of activation across these complementary basal ganglia pathways. The adenosine A1 and A2A receptor agonist combination also maintained its effectiveness in reducing repetitive behavior over a 7-day period. These findings point to novel potential therapeutic targets for development of drug therapies for repetitive behavior in clinical disorders.
Caprioli D, Venniro M, Zhang M, Bossert JM, Warren BL, Hope BT, Shaham Y.
PMID: 28123032 | DOI: 10.1523/JNEUROSCI.3091-16.2017
Abstract
We recently developed a rat model of incubation of methamphetamine craving after choice-based voluntary abstinence. Here, we studied the role of dorsolateral striatum (DLS) and dorsomedial striatum (DMS) in this incubation. We trained rats to self-administer palatable food pellets (6 d, 6 h/d) and methamphetamine (12 d, 6 h/d). We then assessed relapse to methamphetamine seeking under extinction conditions after 1 and 21 abstinence days. Between tests, the rats underwent voluntary abstinence (using a discrete choice procedure between methamphetamine and food; 20 trials/d) for 19 d. We used in situ hybridization to measure the colabeling of the activity marker Fos with Drd1 and Drd2 in DMS and DLS after the tests. Based on the in situ hybridization colabeling results, we tested the causal role of DMS D1 and D2family receptors, and DMS neuronal ensembles in "incubated" methamphetamine seeking, using selective dopamine receptor antagonists (SCH39166 or raclopride) and the Daun02 chemogenetic inactivation procedure, respectively. Methamphetamine seeking was higher after 21 d of voluntary abstinence than after 1 d (incubation of methamphetamine craving). The incubated response was associated with increased Fos expression in DMS but not in DLS; Fos was colabeled with both Drd1 and Drd2 DMS injections of SCH39166 or raclopride selectively decreased methamphetamine seeking after 21 abstinence days. In Fos-lacZ transgenic rats, selective inactivation of relapse test-activated Fos neurons in DMS on abstinence day 18 decreased incubated methamphetamine seeking on day 21. Results demonstrate a role of DMS dopamine D1 and D2 receptors in the incubation of methamphetamine craving after voluntary abstinence and that DMS neuronal ensembles mediate this incubation.
SIGNIFICANCE STATEMENT:
In human addicts, abstinence is often self-imposed and relapse can be triggered by exposure to drug-associated cues that induce drug craving. We recently developed a rat model of incubation of methamphetamine craving after choice-based voluntary abstinence. Here, we used classical pharmacology, in situ hybridization, immunohistochemistry, and the Daun02 inactivation procedure to demonstrate a critical role of dorsomedial striatum neuronal ensembles in this new form of incubation of drug craving.
Bernanke, A;Burnette, E;Murphy, J;Hernandez, N;Zimmerman, S;Walker, QD;Wander, R;Sette, S;Reavis, Z;Francis, R;Armstrong, C;Risher, ML;Kuhn, C;
PMID: 34898621 | DOI: 10.1371/journal.pone.0260577
Females are more affected by psychiatric illnesses including eating disorders, depression, and post-traumatic stress disorder than males. However, the neural mechanisms mediating these sex differences are poorly understood. Animal models can be useful in exploring such neural mechanisms. Conditioned taste aversion (CTA) is a behavioral task that assesses how animals process the competition between associated reinforcing and aversive stimuli in subsequent task performance, a process critical to healthy behavior in many domains. The purpose of the present study was to identify sex differences in this behavior and associated neural responses. We hypothesized that females would value the rewarding stimulus (Boost ) relative to the aversive stimulus (LiCl) more than males in performing CTA. We evaluated behavior (Boost intake, LiCl-induced behaviors, ultrasonic vocalizations (USVs), CTA performance) and Fos activation in relevant brain regions after the acute stimuli [acute Boost (AB), acute LiCl (AL)] and the context-only task control (COT), Boost only task (BOT) and Boost -LiCl task (BLT). Acutely, females drank more Boost than males but showed similar aversive behaviors after LiCl. Females and males performed CTA similarly. Both sexes produced 55 kHz USVs anticipating BOT and inhibited these calls in the BLT. However, more females emitted both 22 kHz and 55 kHz USVs in the BLT than males: the latter correlated with less CTA. Estrous cycle stage also influenced 55 kHz USVs. Fos responses were similar in males and females after AB or AL. Females engaged the gustatory cortex and ventral tegmental area (VTA) more than males during the BOT and males engaged the amygdala more than females in both the BOT and BLT. Network analysis of correlated Fos responses across brain regions identified two unique networks characterizing the BOT and BLT, in both of which the VTA played a central role. In situ hybridization with RNAscope identified a population of D1-receptor expressing cells in the CeA that responded to Boost and D2 receptor-expressing cells that responded to LiCl. The present study suggests that males and females differentially process the affective valence of a stimulus to produce the same goal-directed behavior.
Zhang, K;Erkan, EP;Jamalzadeh, S;Dai, J;Andersson, N;Kaipio, K;Lamminen, T;Mansuri, N;Huhtinen, K;Carpén, O;Hietanen, S;Oikkonen, J;Hynninen, J;Virtanen, A;Häkkinen, A;Hautaniemi, S;Vähärautio, A;
PMID: 35196078 | DOI: 10.1126/sciadv.abm1831
Chemotherapy resistance is a critical contributor to cancer mortality and thus an urgent unmet challenge in oncology. To characterize chemotherapy resistance processes in high-grade serous ovarian cancer, we prospectively collected tissue samples before and after chemotherapy and analyzed their transcriptomic profiles at a single-cell resolution. After removing patient-specific signals by a novel analysis approach, PRIMUS, we found a consistent increase in stress-associated cell state during chemotherapy, which was validated by RNA in situ hybridization and bulk RNA sequencing. The stress-associated state exists before chemotherapy, is subclonally enriched during the treatment, and associates with poor progression-free survival. Co-occurrence with an inflammatory cancer-associated fibroblast subtype in tumors implies that chemotherapy is associated with stress response in both cancer cells and stroma, driving a paracrine feed-forward loop. In summary, we have found a resistant state that integrates stromal signaling and subclonal evolution and offers targets to overcome chemotherapy resistance.
Kiss1 is differentially regulated in male and female mice by the homeodomain transcription factor VAX1
Molecular and cellular endocrinology
Lavalle, SN;Chou, T;Hernandez, J;Naing, NCP;Tonsfeldt, KJ;Hoffmann, HM;Mellon, PL;
PMID: 34098016 | DOI: 10.1016/j.mce.2021.111358
Regulation of Kiss1 transcription is crucial to the development and function of the reproductive axis. The homeodomain transcription factor, ventral anterior homeobox 1 (VAX1), has been implicated as a potential regulator of Kiss1 transcription. However, it is unknown whether VAX1 directly mediates transcription within kisspeptin neurons or works indirectly by acting upstream of kisspeptin neuron populations. This study tested the hypothesis that VAX1 within kisspeptin neurons regulates Kiss1 gene expression. We found that VAX1 acts as a repressor of Kiss1 in vitro and within the male arcuate nucleus in vivo. In female mice, we found that the loss of VAX1 caused a reduction in Kiss1 expression and Kiss1-containing neurons in the anteroventral periventricular nucleus at the time of the preovulatory luteinizing hormone surge, but was compensated by an increase in Kiss1-cFos colocalization. Despite changes in Kiss1 transcription, gonadotropin levels were unaffected and there were no impairments to fertility.
Dohnalová, L;Lundgren, P;Carty, JRE;Goldstein, N;Wenski, SL;Nanudorn, P;Thiengmag, S;Huang, KP;Litichevskiy, L;Descamps, HC;Chellappa, K;Glassman, A;Kessler, S;Kim, J;Cox, TO;Dmitrieva-Posocco, O;Wong, AC;Allman, EL;Ghosh, S;Sharma, N;Sengupta, K;Cornes, B;Dean, N;Churchill, GA;Khurana, TS;Sellmyer, MA;FitzGerald, GA;Patterson, AD;Baur, JA;Alhadeff, AL;Helfrich, EJN;Levy, M;Betley, JN;Thaiss, CA;
PMID: 36517598 | DOI: 10.1038/s41586-022-05525-z
Exercise exerts a wide range of beneficial effects for healthy physiology1. However, the mechanisms regulating an individual's motivation to engage in physical activity remain incompletely understood. An important factor stimulating the engagement in both competitive and recreational exercise is the motivating pleasure derived from prolonged physical activity, which is triggered by exercise-induced neurochemical changes in the brain. Here, we report on the discovery of a gut-brain connection in mice that enhances exercise performance by augmenting dopamine signalling during physical activity. We find that microbiome-dependent production of endocannabinoid metabolites in the gut stimulates the activity of TRPV1-expressing sensory neurons and thereby elevates dopamine levels in the ventral striatum during exercise. Stimulation of this pathway improves running performance, whereas microbiome depletion, peripheral endocannabinoid receptor inhibition, ablation of spinal afferent neurons or dopamine blockade abrogate exercise capacity. These findings indicate that the rewarding properties of exercise are influenced by gut-derived interoceptive circuits and provide a microbiome-dependent explanation for interindividual variability in exercise performance. Our study also suggests that interoceptomimetic molecules that stimulate the transmission of gut-derived signals to the brain may enhance the motivation for exercise.
