Somatostatin Interneurons of the Insula Mediate QR2-Dependent Novel Taste Memory Enhancement
Gould, NL;Kolatt Chandran, S;Kayyal, H;Edry, E;Rosenblum, K;
PMID: 34518366 | DOI: 10.1523/ENEURO.0152-21.2021
Forming long-term memories is crucial for adaptive behavior and survival in changing environments. The molecular consolidation processes which underlie the formation of these long-term memories are dependent on protein synthesis in excitatory and SST-expressing neurons. A centrally important, parallel process to this involves the removal of the memory constraint quinone reductase 2 (QR2), which has been recently shown to enhance memory consolidation for novel experiences in the cortex and hippocampus, via redox modulation. However, it is unknown within which cell type in the cortex removal of QR2 occurs, nor how this affects neuronal function. Here, we use novel taste learning in the mouse anterior insular cortex (aIC) to show that similarly to mRNA translation, QR2 removal occurs in excitatory and SST-expressing neurons. Interestingly, both novel taste and QR2 inhibition reduce excitability specifically within SST, but not excitatory neurons. Furthermore, reducing QR2 expression in SST, but not in PV or excitatory neurons, is sufficient to enhance taste memory. Thus, QR2 mediated intrinsic property changes of SST interneurons in the aIC is a central removable factor to allow novel taste memory formation. This previously unknown involvement of QR2 and SST interneurons in resetting aIC activity hours following learning, describes a molecular mechanism to define cell circuits for novel information. Therefore, the QR2 pathway in SST interneurons provides a fresh new avenue by which to tackle age-related cognitive deficits, while shedding new light onto the functional machinations of long-term memory formation for novel information.
Front Cell Neurosci. 2018 Oct 9;12:341.
Yoo T, Cho H, Lee J, Park H, Yoo YE, Yang E, Kim JY, Kim H, Kim E.
PMID: 30356810 | DOI: 10.3389/fncel.2018.00341
Shank3 is an excitatory postsynaptic scaffolding protein implicated in multiple brain disorders, including autism spectrum disorders (ASD) and Phelan-McDermid syndrome (PMS). Although previous neurobiological studies on Shank3 and Shank3-mutant mice have revealed diverse roles of Shank3 in the regulation of synaptic, neuronal and brain functions, whether Shank3 expression in specific cell types distinctly contributes to mouse phenotypes remains largely unclear. In the present study, we generated two Shank3-mutant mouse lines (exons 14-16) carrying global and GABA neuron-specific deletions and characterized their electrophysiological and behavioral phenotypes. These mouse lines show similar decreases in excitatory synaptic input onto dorsolateral striatal neurons. In addition, the abnormal social and locomotor behaviors observed in global Shank3-mutant mice are strongly mimicked by GABA neuron-specific Shank3-mutant mice, whereas the repetitive and anxiety-like behaviors are only partially mimicked. These results suggest that GABAergic Shank3 (exons 14-16) deletion has strong influences on striatal excitatory synaptic transmission and social and locomotor behaviors in mice.
International journal of molecular sciences
Miranda, CO;Hegedüs, K;Kis, G;Antal, M;
PMID: 37108107 | DOI: 10.3390/ijms24086943
A great deal of evidence supports the inevitable importance of spinal glycinergic inhibition in the development of chronic pain conditions. However, it remains unclear how glycinergic neurons contribute to the formation of spinal neural circuits underlying pain-related information processing. Thus, we intended to explore the synaptic targets of spinal glycinergic neurons in the pain processing region (laminae I-III) of the spinal dorsal horn by combining transgenic technology with immunocytochemistry and in situ hybridization accompanied by light and electron microscopy. First, our results suggest that, in addition to neurons in laminae I-III, glycinergic neurons with cell bodies in lamina IV may contribute substantially to spinal pain processing. On the one hand, we show that glycine transporter 2 immunostained glycinergic axon terminals target almost all types of excitatory and inhibitory interneurons identified by their neuronal markers in laminae I-III. Thus, glycinergic postsynaptic inhibition, including glycinergic inhibition of inhibitory interneurons, must be a common functional mechanism of spinal pain processing. On the other hand, our results demonstrate that glycine transporter 2 containing axon terminals target only specific subsets of axon terminals in laminae I-III, including nonpeptidergic nociceptive C fibers binding IB4 and nonnociceptive myelinated A fibers immunoreactive for type 1 vesicular glutamate transporter, indicating that glycinergic presynaptic inhibition may be important for targeting functionally specific subpopulations of primary afferent inputs.
Proceedings of the National Academy of Sciences of the United States of America
Kim, J;Park, D;Seo, NY;Yoon, TH;Kim, GH;Lee, SH;Seo, J;Um, JW;Lee, KJ;Ko, J;
PMID: 35022233 | DOI: 10.1073/pnas.2110196119
Synaptic cell-adhesion molecules (CAMs) organize the architecture and properties of neural circuits. However, whether synaptic CAMs are involved in activity-dependent remodeling of specific neural circuits is incompletely understood. Leucine-rich repeat transmembrane protein 3 (LRRTM3) is required for the excitatory synapse development of hippocampal dentate gyrus (DG) granule neurons. Here, we report that Lrrtm3-deficient mice exhibit selective reductions in excitatory synapse density and synaptic strength in projections involving the medial entorhinal cortex (MEC) and DG granule neurons, accompanied by increased neurotransmitter release and decreased excitability of granule neurons. LRRTM3 deletion significantly reduced excitatory synaptic innervation of hippocampal mossy fibers (Mf) of DG granule neurons onto thorny excrescences in hippocampal CA3 neurons. Moreover, LRRTM3 loss in DG neurons significantly decreased mossy fiber long-term potentiation (Mf-LTP). Remarkably, silencing MEC-DG circuits protected against the decrease in the excitatory synaptic inputs onto DG and CA3 neurons, excitability of DG granule neurons, and Mf-LTP in Lrrtm3-deficient mice. These results suggest that LRRTM3 may be a critical factor in activity-dependent synchronization of the topography of MEC-DG-CA3 excitatory synaptic connections. Collectively, our data propose that LRRTM3 shapes the target-specific structural and functional properties of specific hippocampal circuits.
Piskol R, Huw LY, Sergin I, Klijn C, Modrusan Z, Kim D, Kljavin NM, Tam R, Patel R, Burton J, Penuel E, Qu X, Koeppen H, Sumiyoshi T, de Sauvage FJ, Lackner MR, de Sousa E Melo F, Kabbarah O.
PMID: 31004000 | DOI: 10.1158/1078-0432.CCR-18-3032
Abstract
PURPOSE:
Four consensus molecular subtypes (CMS1-4) of colorectal cancer (CRC) were identified in primary tumors and found to be associated with distinctive biological features and clinical outcomes. Given that distant metastasis largely accounts for CRC-related mortality, we examined the molecular and clinical attributes of CMS in metastatic CRC (mCRC).
EXPERIMENTAL DESIGN:
We developed a CRC-focused Nanostring based CMS classifier that is ideally suited to interrogate archival tissues. We successfully employ this panel in the CMS classification of FFPE tissues from mCRC cohorts, one of which is comprised of paired primary tumors and metastases. Finally, we developed novel mouse implantation models to enable modelling of CRC in vivo at relevant sites.
RESULTS:
Using our classifier we find that the biological hallmarks of mCRC, including CMS, are in general highly similar to those observed in non-metastatic early stage disease. Importantly, our data demonstrate that CMS1 has the worst outcome in relapsed disease, compared to other CMS. Assigning CMS to primary tumors and their matched metastases revealed mostly concordant subtypes between primary and metastasis. Molecular analysis of matched discordant pairs revealed differences in stromal composition at each site. The development of two novel in vivo orthotopic implantation models further reinforces the notion that extrinsic factors may impact on CMS identification in matched primary and metastatic CRC.
CONCLUSION:
We describe the utility of a Nanostring panel for CMS classification of FFPE clinical samples. Our work reveals the impact of intrinsic and extrinsic factors on CRC heterogeneity during disease progression.
Polgár, E;Dickie, AC;Gutierrez-Mecinas, M;Bell, AM;Boyle, KA;Quillet, R;Rashid, EA;Clark, RA;German, MT;Watanabe, M;Riddell, JS;Todd, AJ;
PMID: 35543635 | DOI: 10.1097/j.pain.0000000000002677
Neurons in the superficial dorsal horn that express the gastrin-releasing peptide receptor (GRPR) are strongly implicated in spinal itch pathways. However, a recent study reported that many of these correspond to vertical cells, a population of interneurons that are thought to transmit nociceptive information. In this study, we have used a GRPRCreERT2 mouse line to identify and target cells that possess Grpr mRNA. We find that the GRPR cells are highly concentrated in lamina I and the outer part of lamina II, that they are all glutamatergic, and that they account for ∼15% of the excitatory neurons in the superficial dorsal horn. We had previously identified 6 neurochemically distinct excitatory interneuron populations in this region based on neuropeptide expression and the GRPR cells are largely separate from these, although they show some overlap with cells that express substance P. Anatomical analysis revealed that the GRPR neurons are indeed vertical cells, and that their axons target each other, as well as arborising in regions that contain projection neurons: lamina I, the lateral spinal nucleus and the lateral part of lamina V. Surprisingly, given the proposed role of GRPR cells in itch, we found that most of the cells received monosynaptic input from Trpv1-expressing (nociceptive) afferents, that the great majority responded to noxious and pruritic stimuli, and that chemogenetically activating them resulted in pain- and itch-related behaviours. Together, these findings suggest that the GRPR cells are involved in spinal cord circuits that underlie both pain and itch.
Yaeger, JDW;Krupp, KT;Summers, TR;Summers, CH;
PMID: 35724928 | DOI: 10.1016/j.neuropharm.2022.109168
Fear-associated memories and behavior are often expressed in contexts/environments distinctively different from those in which they are created. This generalization process contributes to psychological disorders, particularly PTSD. Stress-related neurocircuits in the basolateral amygdala (BLA) receive inputs from hypothalamic orexin (Orx) neurons, which mediate neuronal activity by targeting orexin 1 (Orx1R) and orexin 2 (Orx2R) receptors via opposing functions. In BLA, inhibition of Orx1R or activation of Orx2R ameliorate stress responsiveness and behavior. We discovered that most Orx1R+ cells also express CamKIIα, while a majority of Orx2R+ cells are colocalized with GAD67. Further, Orx1R gene Hcrtr1 expression was positively correlated, and Orx2R gene Hcrtr2 expression was negatively correlated, with freezing in a phenotype-dependent fashion (Escape vs Stay) in the Stress Alternatives Model (SAM). The SAM consists of 4-days of social interaction between test mice and novel larger aggressors. Exits positioned at opposite ends of the SAM oval arena provide opportunities to actively avoid aggression. By Day 2, mice commit to behavioral phenotypes: Escape or Stay. Pharmacologically manipulating Orx receptor activity in the BLA, before Day 3 of the SAM, was followed with standard tests of anxiety: Open Field (OF) and Elevated Plus Maze (EPM). In Stay mice, freezing in response to social conflict and locomotion during SAM interaction (not home cage locomotion) were generalized to OF, and blocked by intra-BLA Orx1R antagonism, but not Orx2R antagonism. Moreover, patterns of social avoidance for Escape and Stay mice were recapitulated in OF, with generalization mediated by Orx1R and Orx2R antagonism, plus Orx2R stimulation.
Yaeger, J;Krupp, K;Jacobs, B;Onserio, B;Meyerink, B;Cain, J;Ronan, P;Renner, K;DiLeone, R;Summers, C;
| DOI: 10.1016/j.biopsych.2021.12.019
BACKGROUND Stress produces differential behavioral responses through select molecular modifications to specific neurocircuitry elements. The orexin system targets key components of this neurocircuitry in the basolateral amygdala (BLA). METHODS We assessed the contribution of intra-BLA Orexin 1 receptors (Orx1R) in the expression of stress-induced phenotypes of mice. Using the Stress Alternatives Model (SAM), a social stress paradigm that produces two behavioral phenotypes, we characterized the role of intra-BLA Orx1R using acute pharmacological inhibition (SB-674042) and genetic knockdown (AAV-U6-Orx1R-shRNA) strategies. RESULTS In the BLA, we observed that Orx1R (HCRTR1) mRNA is predominantly expressed in CamKIIα+ glutamatergic neurons and rarely in GABAergic cells. While there is a slight overlap in HCRTR1 and Orexin 2 receptor (Orx2R; HCRTR2) mRNA expression in the BLA, we find that these receptors are most often expressed in separate cells. Antagonism of intra-BLA Orx1R after phenotype formation shifted behavioral expression from stress sensitive (Stay) to resilient (Escape) responses, an effect that was mimicked by genetic knockdown. Acute inhibition of Orx1R in the BLA also reduced contextual and cued fear freezing responses in Stay animals. This phenotype-specific behavioral change was accompanied by biased molecular transcription favoring HCRTR2 over HCRTR1, and MAPK3 over PLCB1 cell signaling cascades and enhanced BDNF mRNA. CONCLUSIONS Functional reorganization of intra-BLA gene expression is produced by antagonism of Orx1R, which promotes elevated HCRTR2, greater MAPK3, and increased BDNF expression. Together, these results provide evidence for a receptor-driven mechanism that balances pro- and anti-stress responses within the BLA.
Hernández VS, Hernández OR, Perez de la Mora M, Gómora ML, Fuxe K, Eiden LE, Zhang L.
PMID: - | DOI: 10.3389/fncir.2016.00092
The arginine-vasopressin (AVP)-containing hypothalamic magnocellular neurosecretory neurons (VPMNNs) are known for their role in hydro-electrolytic balance control via their projections to the neurohypophysis. Recently, projections from these same neurons to hippocampus, habenula and other brain regions in which vasopressin infusion modulates contingent social and emotionally-affected behaviors, have been reported. Here, we present evidence that VPMNN collaterals also project to the amygdaloid complex, and establish synaptic connections with neurons in central amygdala (CeA). The density of AVP innervation in amygdala was substantially increased in adult rats that had experienced neonatal maternal separation (MS), consistent with our previous observations that MS enhances VPMNN number in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. In the CeA, V1a AVP receptor mRNA was only observed in GABAergic neurons, demonstrated by complete co-localization of V1a transcripts in neurons expressing Gad1 and Gad2 transcripts in CeA using the RNAscope method. V1b and V2 receptor mRNAs were not detected, using the same method. Water-deprivation (WD) for 24 h, which increased the metabolic activity of VPMNNs, also increased anxiety-like behavior measured using the elevated plus maze (EPM) test, and this effect was mimicked by bilateral microinfusion of AVP into the CeA. Anxious behavior induced by either WD or AVP infusion was reversed by CeA infusion of V1a antagonist. VPMNNs are thus a newly discovered source of CeA inhibitory circuit modulation, through which both early-life and adult stress coping signals are conveyed from the hypothalamus to the amygdala.
The Journal of neuroscience : the official journal of the Society for Neuroscience
Fudge, JL;Kelly, EA;Hackett, TA;
PMID: 36280261 | DOI: 10.1523/JNEUROSCI.1453-22.2022
The central extended amygdala (CEA) and ventral pallidum (VP) are involved in diverse motivated behaviors based on rodent models. These structures are conserved, but expanded, in higher primates including human. Corticotropin releasing factor (CRF), a canonical 'stress molecule' associated with the CEA and VP circuitry across species, is dynamically regulated by stress and drugs of abuse and misuse. CRF's effects on circuits critically depend on its colocation with primary 'fast' transmitters, making this crucial for understanding circuit effects. We surveyed the distribution and colocalization of CRF-, VGluT2- (vesicular glutamate transporter 2) and VGAT- (vesicular GABA transporter) mRNA in specific subregions of the CEA and VP in young male monkeys. Although CRF-containing neurons were clustered in the lateral central bed nucleus (BSTLcn), the majority were broadly dispersed throughout other CEA subregions, and the VP. CRF/VGAT-only neurons were highest in the BSTLcn, lateral central amygdala nucleus (CeLcn), and medial central amygdala nucleus (CeM) (74%, 73%, and 85%, respectively). In contrast, lower percentages of CRF/VGAT only neurons populated the sublenticular extended amygdala (SLEAc), ventrolateral bed nucleus (BSTLP), and VP (53%, 54%, 17%, respectively), which had higher complements of CRF/VGAT/VGluT2 labeled neurons (33%, 29%, 67%, respectively). Thus, the majority of CRF-neurons at the 'poles' (BSTLcn and CeLcn/CeM) of the CEA are inhibitory, while the 'extended' BSTLP and SLEAc subregions, and neighboring VP, have a more complex profile with admixtures of 'multiplexed' excitatory CRF neurons. CRF's colocalization with its various fast transmitters is likely circuit-specific, and relevant for understanding CRF actions on specific target sites.SIGNIFICANCE STATEMENT:The central extended amygdala (CEA) and ventral pallidum (VP) regulate multiple motivated behaviors through differential downstream projections. The stress neuropeptide corticotropin releasing factor (CRF) is enriched in the CEA, and is thought to 'set the gain' through modulatory effects on co-expressed primary transmitters. Using protein and transcript assays in monkey, we found that CRF neurons are broadly and diffusely distributed in CEA and VP. CRF mRNA+ neurons colocalize with VGAT (GABA) and VGluT2 (glutamate) mRNAs in different proportions depending on subregion. CRF mRNA was also co-expressed in a subpopulation of VGAT/VGluT2 mRNA ('multiplexed') cells which were most prominent in the VP and 'pallidal'-like parts of the CEA. Heterogeneous CRF and fast transmitter co-expression across CEA/VP subregions implies circuit-specific effects.
Oh, H;Lee, S;Oh, Y;Kim, S;Kim, YS;Yang, Y;Choi, W;Yoo, YE;Cho, H;Lee, S;Yang, E;Koh, W;Won, W;Kim, R;Lee, CJ;Kim, H;Kang, H;Kim, JY;Ku, T;Paik, SB;Kim, E;
PMID: 37321992 | DOI: 10.1038/s41467-023-39203-z
Autism spectrum disorders (ASD) represent neurodevelopmental disorders characterized by social deficits, repetitive behaviors, and various comorbidities, including epilepsy. ANK2, which encodes a neuronal scaffolding protein, is frequently mutated in ASD, but its in vivo functions and disease-related mechanisms are largely unknown. Here, we report that mice with Ank2 knockout restricted to cortical and hippocampal excitatory neurons (Ank2-cKO mice) show ASD-related behavioral abnormalities and juvenile seizure-related death. Ank2-cKO cortical neurons show abnormally increased excitability and firing rate. These changes accompanied decreases in the total level and function of the Kv7.2/KCNQ2 and Kv7.3/KCNQ3 potassium channels and the density of these channels in the enlengthened axon initial segment. Importantly, the Kv7 agonist, retigabine, rescued neuronal excitability, juvenile seizure-related death, and hyperactivity in Ank2-cKO mice. These results suggest that Ank2 regulates neuronal excitability by regulating the length of and Kv7 density in the AIS and that Kv7 channelopathy is involved in Ank2-related brain dysfunctions.
Ataman B, Boulting GL, Harmin DA, Yang MG, Baker-Salisbury M, Yap EL, Malik AN, Mei K, Rubin AA, Spiegel I, Durresi E, Sharma N, Hu LS, Pletikos M, Griffith EC, Partlow JN, Stevens CR, Adli M, Chahrour M, Sestan N, Walsh CA, Berezovskii VK, Livingstone MS
PMID: 27830782 | DOI: 10.1038/nature20111
Sensory stimuli drive the maturation and function of the mammalian nervous system in part through the activation of gene expressionnetworks that regulate synapse development and plasticity. These networks have primarily been studied in mice, and it is not known whether there are species- or clade-specific activity-regulated genes that control features of brain development and function. Here we use transcriptional profiling of human fetal brain cultures to identify an activity-dependent secreted factor, Osteocrin (OSTN), that is induced by membrane depolarization of human but not mouse neurons. We find that OSTN has been repurposed in primates through the evolutionary acquisition of DNA regulatory elements that bind the activity-regulated transcription factor MEF2. In addition, we demonstrate that OSTN is expressed in primate neocortex and restricts activity-dependent dendritic growth in human neurons. These findings suggest that, in response to sensory input, OSTN regulates features of neuronal structure and function that are unique to primates.
