Chen, G;Xu, J;Luo, H;Luo, X;Singh, SK;Ramirez, JJ;James, ML;Mathew, JP;Berger, M;Eroglu, C;Ji, RR;
PMID: 36256481 | DOI: 10.1172/jci.insight.161028
Hevin/Sparcl1 is an astrocyte-secreted protein and regulates synapse formation. Here we show that astrocytic hevin signaling plays a critical role in maintaining chronic pain. Compared to wild-type mice, hevin-null mice exhibited normal mechanical and heat sensitivity but reduced inflammatory pain. Interestingly, hevin-null mice have faster recovery than wild-type mice from neuropathic pain after nerve injury. Intrathecal injection of wild-type hevin was sufficient to induce persistent mechanical allodynia in naïve mice. In hevin-null mice with nerve injury, AAV-mediated re-expression of hevin in GFAP-expressing spinal cord astrocytes could reinstate neuropathic pain. Mechanistically, hevin is crucial for spinal cord NMDA receptor (NMDAR) signaling. Hevin potentiated NMDA currents mediated by the GluN2B-containing NMDARs. Furthermore, intrathecal injection of a neutralizing antibody against hevin alleviated acute and persistent inflammatory pain, postoperative pain, and neuropathic pain. Secreted hevin was detected in mouse cerebrospinal fluid (CSF) and nerve injury significantly increased CSF hevin abundance. Finally, neurosurgery caused rapid and substantial increases in SPARCL1/HEVIN levels in human CSF. Collectively, our findings support a critical role of hevin and astrocytes in the maintenance of chronic pain. Neutralizing of secreted hevin with monoclonal antibody may provide a new therapeutic strategy for treating acute and chronic pain and NMDAR-medicated neurodegeneration.
Cutando, L;Puighermanal, E;Castell, L;Tarot, P;Belle, M;Bertaso, F;Arango-Lievano, M;Ango, F;Rubinstein, M;Quintana, A;Chédotal, A;Mameli, M;Valjent, E;
PMID: 35710984 | DOI: 10.1038/s41593-022-01092-8
The cerebellum, a primary brain structure involved in the control of sensorimotor tasks, also contributes to higher cognitive functions including reward, emotion and social interaction. Although the regulation of these behaviors has been largely ascribed to the monoaminergic system in limbic regions, the contribution of cerebellar dopamine signaling in the modulation of these functions remains largely unknown. By combining cell-type-specific transcriptomics, histological analyses, three-dimensional imaging and patch-clamp recordings, we demonstrate that cerebellar dopamine D2 receptors (D2Rs) in mice are preferentially expressed in Purkinje cells (PCs) and regulate synaptic efficacy onto PCs. Moreover, we found that changes in D2R levels in PCs of male mice during adulthood alter sociability and preference for social novelty without affecting motor functions. Altogether, these findings demonstrate novel roles for D2R in PC function and causally link cerebellar D2R levels of expression to social behaviors.
Liu, JJ;Tsien, RW;Pang, ZP;
PMID: 34980924 | DOI: 10.1038/s41593-021-00984-5
Hypothalamic melanin-concentrating hormone (MCH) polypeptide contributes to regulating energy homeostasis, sleep and memory, although the mechanistic bases of its effects are unknown. In this study, in mice, we uncovered the physiological mechanism underlying the functional role of MCH signaling in projections to the dorsolateral septum (dLS), a region involved in routing hippocampal firing rhythms and encoding spatial memory based on such rhythms. Firing activity within the dLS in response to dorsal CA3 (dCA3) excitation is limited by strong feed-forward inhibition (FFI). We found that MCH synchronizes dLS neuronal firing with its dCA3 inputs by enhancing GABA release, which subsequently reduces the FFI and augments dCA3 excitatory input strength, both via pre-synaptic mechanisms. At the functional level, our data reveal a role for MCH signaling in the dLS in facilitating spatial memory. These findings support a model in which peptidergic signaling within the dLS modulates dorsal hippocampal output and supports memory encoding.
Rytova V, Ganella DE, Hawkes D, Bathgate RAD, Ma S and Gundlach AL
PMID: 30891856 | DOI: 10.1002/hipo.23089
Anxiety disorders are highly prevalent in modern society and better treatments are required. Key brain areas and signaling systems underlying anxiety include prefrontal cortex, hippocampus, and amygdala, and monoaminergic and peptidergic systems, respectively. Hindbrain GABAergic projection neurons that express the peptide, relaxin-3, broadly innervate the forebrain, particularly the septum and hippocampus, and relaxin-3 acts via a Gi/o -protein-coupled receptor known as the relaxin-family peptide 3 receptor (RXFP3). Thus, relaxin-3/RXFP3 signaling is implicated in modulation of arousal, motivation, mood, memory, and anxiety. Ventral hippocampus (vHip) is central to affective and cognitive processing and displays a high density of relaxin-3-positive nerve fibers and RXFP3 binding sites, but the identity of target neurons and associated effects on behavior are unknown. Therefore, in adult, male rats, we assessed the neurochemical nature of hippocampal RXFP3 mRNA-expressing neurons and anxiety-like and social behavior following chronic RXFP3 activation in vHip by viral vector expression of an RXFP3-selective agonist peptide, R3/I5. RXFP3 mRNA detected by fluorescent in situ hybridization was topographically distributed across the hippocampus in somatostatin- and parvalbumin-mRNA expressing GABA neurons. Chronic RXFP3 activation in vHip increased anxiety-like behavior in the light-dark box and elevated-plus maze, but not the large open-field test, and reduced social interaction with a conspecific stranger. Our data reveal disruptive effects of persistent RXFP3 signaling on hippocampal GABA networks important in anxiety; and identify a potential therapeutic target for anxiety disorders that warrants further investigation in relevant preclinical models.
Newton, D;Oh, H;Shukla, R;Misquitta, K;Fee, C;Banasr, M;Sibille, E;
| DOI: 10.1016/j.biopsych.2021.10.015
Introduction Information processing in cortical cell microcircuits involves regulation of excitatory pyramidal (PYR) cells by inhibitory Somatostatin- (SST), Parvalbumin- (PV), and Vasoactive intestinal peptide- (VIP) expressing interneurons. Human post-mortem and rodent studies show impaired PYR-cell dendritic morphology and decreased SST-cell markers in MDD or after chronic stress. However, knowledge of coordinated changes across microcircuit cell-types is virtually absent. Methods We investigated the transcriptomic effects of unpredictable chronic mild stress (UCMS) on distinct microcircuit cell-types in the medial prefrontal cortex (Cingulate regions 24a/b and 32) in mice. C57Bl/6 mice, exposed to UCMS or control housing for five weeks, were assessed for anxiety- and depressive-like behaviors. Microcircuit cell-types were laser-microdissected and processed for RNA-sequencing. Results UCMS induced predicted elevations in behavioral emotionality in mice. DESeq2 analysis revealed unique differentially-expressed genes in each cell-type after UCMS. Pre-synaptic functions, oxidative stress response, metabolism, and translational regulation were differentially dysregulated across cell-types, whereas nearly all cell-types showed downregulated post-synaptic gene signatures. Across the cortical microcircuit, we observed a shift from a distributed transcriptomic coordination across cell-types in controls towards UCMS-induced increased coordination between PYR-, SST- and PV-cells, and hub-like role for PYR-cells. Lastly, we identified a microcircuit-wide coexpression network enriched in synaptic, bioenergetic, and oxidative stress response genes that correlated with UCMS-induced behaviors. Conclusions These findings suggest cell-specific deficits, microcircuit-wide synaptic reorganization, and a shift in cells regulating the cortical excitation-inhibition balance, suggesting increased coordinated regulation of PYR-cells by SST- and PV-cells.
Gu, X;Zhang, YZ;O'Malley, JJ;De Preter, CC;Penzo, M;Hoon, MA;
PMID: 36894654 | DOI: 10.1038/s41593-023-01268-w
Supraspinal brain regions modify nociceptive signals in response to various stressors including stimuli that elevate pain thresholds. The medulla oblongata has previously been implicated in this type of pain control, but the neurons and molecular circuits involved have remained elusive. Here we identify catecholaminergic neurons in the caudal ventrolateral medulla that are activated by noxious stimuli in mice. Upon activation, these neurons produce bilateral feed-forward inhibition that attenuates nociceptive responses through a pathway involving the locus coeruleus and norepinephrine in the spinal cord. This pathway is sufficient to attenuate injury-induced heat allodynia and is required for counter-stimulus induced analgesia to noxious heat. Our findings define a component of the pain modulatory system that regulates nociceptive responses.
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.
McDermott JE, Goldblatt D, Paradis S.
PMID: 29981480 | DOI: 10.1016/j.mcn.2018.06.008
To understand how proper circuit formation and function is established in the mammalian brain, it is necessary to define the genes and signaling pathways that instruct excitatory and inhibitory synapse development. We previously demonstrated that the ligand-receptor pair, Sema4D and Plexin-B1, regulates inhibitory synapse development on an unprecedentedly fast time-scale while having no effect on excitatory synapse development. Here, we report previously undescribed synaptogenic roles for Sema4A and Plexin-B2 and provide new insight into Sema4D and Plexin-B1 regulation of synapse development in rodent hippocampus. First, we show that Sema4a, Sema4d, Plxnb1, and Plxnb2 have distinct and overlapping expression patterns in neurons and glia in the developing hippocampus. Second, we describe a requirement for Plexin-B1 in both the presynaptic axon of inhibitory interneurons as well as the postsynaptic dendrites of excitatory neurons for Sema4D-dependent inhibitory synapse development. Third, we define a new synaptogenic activity for Sema4A in mediating inhibitory and excitatory synapse development. Specifically, we demonstrate that Sema4A signals through the same pathway as Sema4D, via the postsynaptic Plexin-B1 receptor, to promote inhibitory synapse development. However, Sema4A also signals through the Plexin-B2 receptor to promote excitatory synapse development. Our results shed new light on the molecular cues that promote the development of either inhibitory or excitatory synapses in the mammalian hippocampus.
Becker, LJ;Fillinger, C;Waegaert, R;Journée, SH;Hener, P;Ayazgok, B;Humo, M;Karatas, M;Thouaye, M;Gaikwad, M;Degiorgis, L;Santin, MDN;Mondino, M;Barrot, M;Ibrahim, EC;Turecki, G;Belzeaux, R;Veinante, P;Harsan, LA;Hugel, S;Lutz, PE;Yalcin, I;
PMID: 37069164 | DOI: 10.1038/s41467-023-37878-y
While depression and chronic pain are frequently comorbid, underlying neuronal circuits and their psychopathological relevance remain poorly defined. Here we show in mice that hyperactivity of the neuronal pathway linking the basolateral amygdala to the anterior cingulate cortex is essential for chronic pain-induced depression. Moreover, activation of this pathway in naive male mice, in the absence of on-going pain, is sufficient to trigger depressive-like behaviors, as well as transcriptomic alterations that recapitulate core molecular features of depression in the human brain. These alterations notably impact gene modules related to myelination and the oligodendrocyte lineage. Among these, we show that Sema4a, which was significantly upregulated in both male mice and humans in the context of altered mood, is necessary for the emergence of emotional dysfunction. Overall, these results place the amygdalo-cingulate pathway at the core of pain and depression comorbidity, and unravel the role of Sema4a and impaired myelination in mood control.
Nat Neurosci. 2019 Jan;22(1):47-56.
Fu H, Possenti A, Freer R, Nakano Y, Villegas NCH, Tang M, Cauhy PVM, Lassus BA, Chen S, Fowler SL, Figueroa HY, Huey ED, Johnson GVW, Vendruscolo M, Duff KE.
PMID: 30559469 | DOI: 10.1038/s41593-018-0298-7
Excitatory neurons are preferentially impaired in early Alzheimer's disease but the pathways contributing to their relative vulnerability remain largely unknown. Here we report that pathological tau accumulation takes place predominantly in excitatory neurons compared to inhibitory neurons, not only in the entorhinal cortex, a brain region affected in early Alzheimer's disease, but also in areas affected later by the disease. By analyzing RNA transcripts from single-nucleus RNA datasets, we identified a specific tau homeostasis signature of genes differentially expressed in excitatory compared to inhibitory neurons. One of the genes, BCL2-associated athanogene 3 (BAG3), a facilitator of autophagy, was identified as a hub, or master regulator, gene. We verified that reducing BAG3 levels in primary neurons exacerbated pathological tau accumulation, whereas BAG3 overexpression attenuated it. These results define a tau homeostasis signature that underlies the cellular and regional vulnerability of excitatory neurons to tau pathology.
Yu, XD;Zhu, Y;Sun, QX;Deng, F;Wan, J;Zheng, D;Gong, W;Xie, SZ;Shen, CJ;Fu, JY;Huang, H;Lai, HY;Jin, J;Li, Y;Li, XM;
PMID: 36446933 | DOI: 10.1038/s41593-022-01200-8
Anxiety-like behaviors in mice include social avoidance and avoidance of bright spaces. Whether these features are distinctly regulated is unclear. We demonstrate that in mice, social and anxiogenic stimuli, respectively, increase and decrease serotonin (5-HT) levels in basal amygdala (BA). In dorsal raphe nucleus (DRN), 5-HT∩vGluT3 neurons projecting to BA parvalbumin (DRN5-HT∩vGluT3-BAPV) and pyramidal (DRN5-HT∩vGluT3-BAPyr) neurons have distinct intrinsic properties and gene expression and respond to anxiogenic and social stimuli, respectively. Activation of DRN5-HT∩vGluT3→BAPV inhibits 5-HT release via GABAB receptors on serotonergic terminals in BA, inducing social avoidance and avoidance of bright spaces. Activation of DRN5-HT∩vGluT3→BA neurons inhibits two subsets of BAPyr neurons via 5-HT1A receptors (HTR1A) and 5-HT1B receptors (HTR1B). Pharmacological inhibition of HTR1A and HTR1B in BA induces avoidance of bright spaces and social avoidance, respectively. These findings highlight the functional significance of heterogenic inputs from DRN to BA subpopulations in the regulation of separate anxiety-related behaviors.
Proceedings of the National Academy of Sciences of the United States of America
Dias, CM;Issac, B;Sun, L;Lukowicz, A;Talukdar, M;Akula, SK;Miller, MB;Walsh, K;Rockowitz, S;Walsh, CA;
PMID: 37252957 | DOI: 10.1073/pnas.2300052120
Short trinucleotide expansions at the FMR1 locus are associated with the late-onset condition fragile X-associated tremor/ataxia syndrome (FXTAS), which shows very different clinical and pathological features from fragile X syndrome (associated with longer expansions), with no clear molecular explanation for these marked differences. One prevailing theory posits that the shorter, premutation expansion uniquely causes extreme neurotoxic increases in FMR1 mRNA (i.e., four to eightfold increases), but evidence to support this hypothesis is largely derived from analysis of peripheral blood. We applied single-nucleus RNA sequencing to postmortem frontal cortex and cerebellum from 7 individuals with premutation and matched controls (n = 6) to assess cell type-specific molecular neuropathology. We found only modest upregulation (~1.3-fold) of FMR1 in some glial populations associated with premutation expansions. In premutation cases, we also identified decreased astrocyte proportions in the cortex. Differential expression and gene ontology analysis demonstrated altered neuroregulatory roles of glia. Using network analyses, we identified cell type-specific and region-specific patterns of FMR1 protein target gene dysregulation unique to premutation cases, with notable network dysregulation in the cortical oligodendrocyte lineage. We used pseudotime trajectory analysis to determine how oligodendrocyte development was altered and identified differences in early gene expression in oligodendrocyte trajectories in premutation cases specifically, implicating early cortical glial developmental perturbations. These findings challenge dogma regarding extremely elevated FMR1 increases in FXTAS and implicate glial dysregulation as a critical facet of premutation pathophysiology, representing potential unique therapeutic targets directly derived from the human condition.
