Leithead, AB;Godino, A;Barbier, M;Harony-Nicolas, H;
PMID: 37245781 | DOI: 10.1016/j.biopsych.2023.05.016
The posterior intralaminar (PIL) complex of the thalamus is a multimodal nucleus that has been implicated in maternal behaviors and conspecific social behaviors in male and female rodents. Glutamatergic neurons are a major component of the PIL; however, their specific activity and role during social interactions has not yet been assessed.We used immunohistochemistry for the immediate early gene c-fos as a proxy for neuronal activity in the PIL of mice exposed to a novel social stimulus, a novel object stimulus, or no stimulus. We then used fiber photometry to record neural activity of glutamatergic neurons in the PIL in real-time during social and non-social interactions. Finally, we used inhibitory DREADDs in glutamatergic PIL neurons and tested social preference and social habituation-dishabituation.We observed significantly more c-fos-positive cells in the PIL of mice exposed to social versus object or no stimuli. Neural activity of PIL glutamatergic neurons was increased when male and female mice were engaged in social interaction with a same-sex juvenile or opposite-sex adult, but not a toy mouse. Neural activity positively correlated with social investigation bout length and negatively correlated with chronological order of bouts. Social preference was unaffected by inhibition; however, inhibiting activity of glutamatergic neurons in the PIL delayed the time it took female mice to form social habituation.Together these findings suggest that glutamatergic PIL neurons respond to social stimuli in both male and female mice and may regulate perceptual encoding of social information to facilitate recognition of social stimuli.
Fabre PJ, Leleu M, Mascrez B, Lo Giudice Q, Cobb J, Duboule D.
PMID: 30223853 | DOI: 10.1186/s12915-018-0570-z
Abstract
BACKGROUND:
Global analyses of gene expression during development reveal specific transcription patterns associated with the emergence of various cell types, tissues, and organs. These heterogeneous patterns are instrumental to ensure the proper formation of the different parts of our body, as shown by the phenotypic effects generated by functional genetic approaches. However, variations at the cellular level can be observed within each structure or organ. In the developing mammalian limbs, expression of Hox genes from the HoxD cluster is differentially controlled in space and time, in cells that will pattern the digits and the forearms. While the Hoxd genes broadly share a common regulatory landscape and large-scale analyses have suggested a homogenous Hox gene transcriptional program, it has not previously been clear whether Hoxd genes are expressed together at the same levels in the same cells.
RESULTS:
We report a high degree of heterogeneity in the expression of the Hoxd11 and Hoxd13 genes. We analyzed single-limb bud cell transcriptomes and show that Hox genes are expressed in specific combinations that appear to match particular cell types. In cells giving rise to digits, we find that the expression of the five relevant Hoxd genes (Hoxd9 to Hoxd13) is unbalanced, despite their control by known global enhancers. We also report that specific combinatorial expression follows a pseudo-time sequence, which is established based on the transcriptional diversity of limb progenitors.
CONCLUSIONS:
Our observations reveal the existence of distinct combinations of Hoxd genes at the single-cell level during limb development. In addition, we document that the increasing combinatorial expression of Hoxd genes in this developing structure is associated with specific transcriptional signatures and that these signatures illustrate a temporal progression in the differentiation of these cells.
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.
Kamitakahara A, Wu HH, Levitt P.
PMID: 28758209 | DOI: 10.1002/cne.24294
Detailed anatomical tracing and mapping of the viscerotopic organization of the vagal motor nuclei has provided insight into autonomic function in health and disease. To further define specific cellular identities, we paired information based on visceral connectivity with a cell-type specific marker of a subpopulation of neurons in the dorsal motor nucleus of the vagus (DMV) and nucleus ambiguus (nAmb) that express the autism-associated MET receptor tyrosine kinase. As gastrointestinal disturbances are common in children with autism spectrum disorder (ASD), we sought to define the relationship between MET-expressing (MET+) neurons in the DMV and nAmb, and the gastrointestinal tract. Using wholemount tissue staining and clearing, or retrograde tracing in a METEGFP transgenic mouse, we identify three novel subpopulations of EGFP+ vagal brainstem neurons: 1) EGFP+ neurons in the nAmb projecting to the esophagus or laryngeal muscles, 2) EGFP+ neurons in the medial DMV projecting to the stomach, and 3) EGFP+ neurons in the lateral DMV projecting to the cecum and/or proximal colon. Expression of the MET ligand, hepatocyte growth factor (HGF), by tissues innervated by vagal motor neurons during fetal development reveal potential sites of HGF-MET interaction. Furthermore, similar cellular expression patterns of MET in the brainstem of both the mouse and nonhuman primate suggest that MET expression at these sites is evolutionarily conserved. Together, the data suggest that MET+ neurons in the brainstem vagal motor nuclei are anatomically positioned to regulate distinct portions of the gastrointestinal tract, with implications for the pathophysiology of gastrointestinal comorbidities of ASD.
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.
Dis Model Mech. 2019 Jan 14.
Jones W Jr, Rodriguez J, Bassnett S.
PMID: PMID: 30642872 | DOI: DOI:10.1242/dmm.037283
Fibrillin is an evolutionarily ancient protein that lends elasticity and resiliency to a variety of tissues. In humans, mutations in fibrillin-1 cause Marfan and related syndromes, conditions in which the eye is often severely affected. To gain insights into the ocular sequelae of Marfan syndrome, we targeted Fbn1 in mouse lens or non-pigmented ciliary epithelium (NPCE). Conditional knockout of Fbn1 in NPCE, but not lens, profoundly affected the ciliary zonule, the system of fibrillin-rich fibers that centers the lens in the eye. The tensile strength of the fibrillin-depleted zonule was reduced substantially, due to a shift toward production of smaller caliber fibers. By three months, zonular fibers invariably ruptured and mice developed ectopia lentis, a hallmark of Marfan syndrome. At later stages, untethered lenses lost their polarity and developed cataracts, and the length and volume of mutant eyes increased. This model thus captures key aspects of Marfan-related syndromes, providing insights into the role of fibrillin-1 in eye development and disease.
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.
Liu, Y;Guerrero-Juarez, C;Xiao, F;Shettigar, N;Ramos, R;Kuan, C;Lin, Y;de Jesus Martinez Lomeli, L;Park, J;Oh, J;Liu, R;Lin, S;Tartaglia, M;Yang, R;Yu, Z;Nie, Q;Li, J;Plikus, M;
| DOI: 10.1016/j.devcel.2022.06.005
Hair follicle stem cells are regulated by dermal papilla fibroblasts, their principal signaling niche. Overactivation of Hedgehog signaling in the niche dramatically accelerates hair growth and induces follicle multiplication in mice. On single-cell RNA sequencing, dermal papilla fibroblasts increase heterogeneity to include new Wnt5ahigh states. Transcriptionally, mutant fibroblasts activate regulatory networks for Gli1, Alx3, Ebf1, Hoxc8, Sox18, and Zfp239. These networks jointly upregulate secreted factors for multiple hair morphogenesis and hair-growth-related pathways. Among these is non-conventional TGF-β ligand Scube3. We show that in normal mouse skin, Scube3 is expressed only in dermal papillae of growing, but not in resting follicles. SCUBE3 protein microinjection is sufficient to induce new hair growth, and pharmacological TGF-β inhibition rescues mutant hair hyper-activation phenotype. Moreover, dermal-papilla-enriched expression of SCUBE3 and its growth-activating effect are partially conserved in human scalp hair follicles. Thus, Hedgehog regulates mesenchymal niche function in the hair follicle via SCUBE3/TGF-β mechanism.
Becker-Krail, D;Ketchesin, K;Burns, J;Zong, W;Hildebrand, M;DePoy, L;Vadnie, C;Tseng, G;Logan, R;Huang, Y;McClung, C;
| DOI: 10.1016/j.biopsych.2022.02.007
Background Substance use disorders (SUDs) are associated with disruptions in circadian rhythms. Both human and animal work has shown the integral role for circadian clocks in the modulation of reward behaviors. Interestingly, astrocytes have emerged as key regulators of circadian rhythmicity. However, no studies to date have identified the role of circadian astrocyte function in the nucleus accumbens (NAc), a hub for reward regulation, or determined the importance of these rhythms for reward-related behavior. Methods Using astrocyte-specific RNA-sequencing across time-of-day, we first characterized diurnal variation of the NAc astrocyte transcriptome. We then investigated the functional significance of this circadian regulation through viral-mediated disruption of molecular clock function in NAc astrocytes, followed by assessment of reward-related behaviors, metabolic-related molecular assays, and whole-cell electrophysiology in the NAc. Results Strikingly, ∼43% of the astrocyte transcriptome has a diurnal rhythm and key metabolic pathways were enriched among the top rhythmic genes. Moreover, mice with a viral-mediated loss of molecular clock function in NAc astrocytes show a significant increase in locomotor response to novelty, exploratory drive, operant food self-administration and motivation. At the molecular level, these animals also show disrupted metabolic gene expression, along with significant downregulation of both lactate and glutathione levels in the NAc. Importantly, loss of NAc astrocyte clock function also significantly altered glutamatergic signaling onto neighboring medium spiny neurons, alongside upregulated glutamate-related gene expression. Conclusions Taken together, these findings demonstrate a novel role for astrocyte circadian molecular clock function in the regulation of the NAc and reward-related behaviors.
Acta pharmacologica Sinica
Zhang, YM;Ye, LY;Li, TY;Guo, F;Guo, F;Li, Y;Li, YF;
PMID: 34811511 | DOI: 10.1038/s41401-021-00807-0
Hypidone hydrochloride (YL-0919) is a novel antidepressant in clinical phase II trial. Previous studies show that YL-0919 is a selective 5-HT (serotonin) reuptake inhibitor, 5-HT1A receptor partial agonist, and 5-HT6 receptor agonist, which exerts antidepressant effects in various animal models, but its effects on neural function remain unclear. Medial prefrontal cortex (mPFC), a highly evolved brain region, controls highest order cognitive functions and emotion regulation. In this study we investigated the effects of YL-0919 on the mPFC function, including the changes in neuronal activities using electrophysiological recordings. Extracellular recording (in vivo) showed that chronic administration of YL-0919 significantly increased the spontaneous discharges of mPFC neurons. In mouse mPFC slices, whole-cell recording revealed that perfusion of YL-0919 significantly increased the frequency of sEPSCs, but decreased the frequency of sIPSCs. Then we conducted whole-cell recording in mPFC slices of GAD67-GFP transgenic mice, and demonstrated that YL-0919 significantly inhibited the excitability of GABAergic neurons. In contrast, it did not alter the excitability of pyramidal neurons in mPFC slices of normal mice. Moreover, the inhibition of GABAergic neurons by YL-0919 was prevented by pre-treatment with 5-HT1A receptor antagonist WAY 100635. Finally, chronic administration of YL-0919 significantly increased the phosphorylation levels of mTOR and GSK-3β in the mPFC as compared with vehicle. Taken together, our results demonstrate that YL-0919 enhances the excitability of mPFC via a disinhibition mechanism to fulfill its rapid antidepressant neural mechanism, which was accomplished by 5-HT1A receptor-mediated inhibition of inhibitory GABAergic interneurons.
J Periodontal Res. 2015 Jul 27.
Matthews BG, Roguljic H, Franceschetti T, Roeder E, Matic I, Vidovic I, Joshi P, Kum KY, Kalajzic I.
PMID: 26215316 | DOI: 10.1111/jre.12309
Abstract BACKGROUND AND OBJECTIVE: Cementum and bone are similar mineralized tissues, but cementum accumulates much more slowly than bone, does not have vasculature or innervation and does not undergo remodeling. Despite these differences, there are no well-established markers to distinguish cementoblasts from other mature mineralizing cells such as osteoblasts and odontoblasts. The purpose of this study was to assess differences in gene expression between cementoblasts and osteoblasts using gene profiling of cell populations isolated directly from osteocalcin-green fluorescent protein (OC-GFP) transgenic mice. MATERIAL AND METHODS: OC-GFP reporter mice were used as they show labeling of cementoblasts, osteoblasts and odontoblasts, but not of periodontal ligament fibroblasts, within the periodontium. We sorted cells digested from the molar root surface to isolate OC-GFP+ cementoblasts. Osteoblasts were isolated from calvarial digests. Microarray analysis was performed, and selected results were confirmed by real-time PCR and immunostaining or in situ hybridization. RESULTS: Microarray analysis identified 95 genes that were expressed at least two-fold higher in cementoblasts than in osteoblasts. Our analysis indicated that the Wnt signaling pathway was differentially regulated, as were genes related to skeletal development. Real-time PCR confirmed that expression of the Wnt inhibitors Wnt inhibitory factor 1 (Wif1) and secreted frizzled-related protein 1 (Sfrp1) was elevated in cementoblasts compared with osteoblasts, and Wif1 expression was localized to the apical root region. In addition, the transcription factor BARX homeobox 1 (Barx1) was expressed at higher levels in cementoblasts, and immunohistochemistry indicated that BARX1 was expressed in apical cementoblasts and cementocytes, but not in osteoblasts or odontoblasts. CONCLUSION: The OC-GFP mouse provides a good model for selectively isolating cementoblasts, and allowed for identification of differentially expressed genes between cementoblasts and osteoblasts.
Biological Psychiatry Global Open Science
Jiang, S;Zhang, H;Eiden, L;
| DOI: 10.1016/j.bpsgos.2023.04.001
Background The neuropeptide PACAP is a master regulator of central and peripheral stress responses, yet it is not clear how PACAP projections throughout the brain execute endocrine and behavioral stress responses. Methods We used AAV neuronal tracing, an acute restraint stress (ARS) paradigm, and intersectional genetics, in C57Bl6 mice, to identify PACAP-containing circuits controlling stress-induced behavior and endocrine activation. Results PACAP deletion from forebrain excitatory neurons, including a projection directly from medial prefrontal cortex (mPFC) to hypothalamus, impairs c-fos activation and CRH mRNA elevation in PVN after 2 hr of restraint, without affecting ARS-induced hypophagia, or c-fos elevation in non-hypothalamic brain. Elimination of PACAP within projections from lateral parabrachial nucleus to extended amygdala (EA), on the other hand, attenuates ARS-induced hypophagia, along with EA fos induction, without affecting ARS-induced CRH mRNA elevation in PVN. PACAP projections to EA terminate at PKCδ neurons in both central amygdala (CeA) and oval nuclei of bed nucleus of stria terminalis (BNSTov). Silencing of PKCδ neurons in CeA, but not in BNSTov, attenuates ARS-induced hypophagia. Experiments were carried out in mice of both sexes with n>5 per group. Conclusions A frontocortical descending PACAP projection controls PVN CRH mRNA production, to maintain hypothalamo-pituitary adrenal (HPA) axis activation, and regulate the endocrine response to stress. An ascending PACAPergic projection from eLPBn to PKCδ neurons in central amygdala regulates behavioral responses to stress. Defining two separate limbs of the acute stress response provides broader insight into the specific brain circuitry engaged by the psychogenic stress response.
