Muhl, L;Mocci, G;Pietilä, R;Liu, J;He, L;Genové, G;Leptidis, S;Gustafsson, S;Buyandelger, B;Raschperger, E;Hansson, EM;Björkegren, JLM;Vanlandewijck, M;Lendahl, U;Betsholtz, C;
PMID: 36283392 | DOI: 10.1016/j.devcel.2022.09.015
Smooth muscle cells (SMCs) execute important physiological functions in numerous vital organ systems, including the vascular, gastrointestinal, respiratory, and urogenital tracts. SMC differ morphologically and functionally at these different anatomical locations, but the molecular underpinnings of the differences remain poorly understood. Here, using deep single-cell RNA sequencing combined with in situ gene and protein expression analysis in four murine organs-heart, aorta, lung, and colon-we identify a molecular basis for high-level differences among vascular, visceral, and airway SMC, as well as more subtle differences between, for example, SMC in elastic and muscular arteries and zonation of elastic artery SMC along the direction of blood flow. Arterial SMC exhibit extensive organotypic heterogeneity, whereas venous SMC are similar across organs. We further identify a specific SMC subtype within the pulmonary vasculature. This comparative SMC cross-organ resource offers insight into SMC subtypes and their specific functions.
Chen, Z;Chen, G;Zhong, J;Jiang, S;Lai, S;Xu, H;Deng, X;Li, F;Lu, S;Zhou, K;Li, C;Liu, Z;Zhang, X;Zhu, Y;
PMID: 36028570 | DOI: 10.1038/s41380-022-01742-0
Feeding behavior is regulated by both the homeostatic needs of the body and hedonic values of the food. Easy access to palatable energy-dense foods and the consequent obesity epidemic stress the urgent need for a better understanding of neural circuits that regulate hedonic feeding. Here, we report that neurotensin-positive neurons in the lateral septum (LSNts) play a crucial role in regulating hedonic feeding. Silencing LSNts specifically promotes feeding of palatable food, whereas activation of LSNts suppresses overall feeding. LSNts neurons project to the tuberal nucleus (TU) via GABA signaling to regulate hedonic feeding, while the neurotensin signal from LSNts→the supramammillary nucleus (SUM) is sufficient to suppress overall feeding. In vivo calcium imaging and optogenetic manipulation reveal two populations of LSNts neurons that are activated and inhibited during feeding, which contribute to food seeking and consumption, respectively. Chronic activation of LSNts or LSNts→TU is sufficient to reduce high-fat diet-induced obesity. Our findings suggest that LSNts→TU is a key pathway in regulating hedonic feeding.
Qi, Y;Lee, NJ;Ip, CK;Enriquez, R;Tasan, R;Zhang, L;Herzog, H;
PMID: 35167990 | DOI: 10.1016/j.molmet.2022.101455
Aguti-related protein (AGRP) neurons in the arcuate nucleus of the hypothalamus (ARC), which co-express neuropeptide Y (NPY), are key regulators of feeding and energy homeostasis. However, the precise role NPY has within these neurons and the specific pathways that it control are still unclear. In this article, we aimed to determine what aspects of feeding behaviour and energy homeostasis are controlled by NPY originating from AGRP neurons and which Y-receptor pathways are utilised to fulfil this function.Novel conditional Agrpcre/+;Npylox/lox knockout mice were generated and comprehensively phenotyped, both under standard chow as well as high-fat-diet conditions. Designer receptor exclusively activated by designer drugs (DREADD) technology was used to assess the altered responses on feeding and energy homeostasis control in the absence of NPY in these neurons. Rescue experiments utilising Npy1r- and Npy2r-selective NPY ligands were performed to assess which component of the energy homeostasis control is dependent by which specific Y-receptor pathway.We show that the specific deletion of Npy only in AGRP neurons leads to a paradoxical mild obese phenotype associated with reduced locomotion and energy expenditure and increased feeding and Respiratory Quotient (RQ) that remain elevated under a positive energy balance. The activation of Npy-deficient AGRP neurons via DREADD's is still able to drive feeding, yet with a delayed onset. Additionally, Clozapine-N-oxide (CNO) treatment reduces locomotion without impacting on energy expenditure. Rescue experiments re-introducing Npy1r- and Npy2r-selective NPY ligands revealed that the increased feeding and RQ are mostly driven by Npy1r, whereas energy expenditure and locomotion are controlled by Npy2r signalling.Together, these results demonstrate that NPY originating from AGRP neurons is not only critical to initiate but also for continuously driving feeding, and we for the first time identify which Y-receptor controls which pathway.
The Journal of comparative neurology
Karthik, S;Huang, D;Delgado, Y;Laing, JJ;Peltekian, L;Iverson, GN;Grady, F;Miller, RL;McCann, CM;Fritzsch, B;Iskusnykh, IY;Chizhikov, VV;Geerling, JC;
PMID: 35134251 | DOI: 10.1002/cne.25307
Diverse neurons in the parabrachial nucleus (PB) communicate with widespread brain regions. Despite evidence linking them to a variety of homeostatic functions, it remains difficult to determine which PB neurons influence which functions because their subpopulations intermingle extensively. An improved framework for identifying these intermingled subpopulations would help advance our understanding of neural circuit functions linked to this region. Here, we present the foundation of a developmental-genetic ontology that classifies PB neurons based on their intrinsic, molecular features. By combining transcription factor labeling with Cre fate-mapping, we find that the PB is a blend of two, developmentally distinct macropopulations of glutamatergic neurons. Neurons in the first macropopulation express Lmx1b (and, to a lesser extent, Lmx1a) and are mutually exclusive with those in a second macropopulation, which derive from precursors expressing Atoh1. This second, Atoh1-derived macropopulation includes many Foxp2-expressing neurons, but Foxp2 also identifies a subset of Lmx1b-expressing neurons in the Kölliker-Fuse nucleus (KF) and a population of GABAergic neurons ventrolateral to the PB ("caudal KF"). Immediately ventral to the PB, Phox2b-expressing glutamatergic neurons (some coexpressing Lmx1b) occupy the KF, supratrigeminal nucleus, and reticular formation. We show that this molecular framework organizes subsidiary patterns of adult gene expression (including Satb2, Calca, Grp, and Pdyn) and predicts output projections to the amygdala (Lmx1b), hypothalamus (Atoh1), and hindbrain (Phox2b/Lmx1b). Using this molecular ontology to organize, interpret, and communicate PB-related information could accelerate the translation of experimental findings from animal models to human patients.
Vanlandewijck M, He L, Mäe MA, Andrae J, Ando K, Del Gaudio F, Nahar K, Lebouvier T, Laviña B, Gouveia L, Sun Y, Raschperger E, Räsänen M, Zarb Y, Mochizuki N, Keller A, Lendahl U, Betsholtz C.
PMID: 29443965 | DOI: 10.1038/nature25739
Cerebrovascular disease is the third most common cause of death in developed countries, but our understanding of the cells that compose the cerebral vasculature is limited. Here, using vascular single-cell transcriptomics, we provide molecular definitions for the principal types of blood vascular and vessel-associated cells in the adult mouse brain. We uncover the transcriptional basis of the gradual phenotypic change (zonation) along the arteriovenous axis and reveal unexpected cell type differences: a seamless continuum for endothelial cells versus a punctuated continuum for mural cells. We also provide insight into pericyte organotypicity and define a population of perivascular fibroblast-like cells that are present on all vessel types except capillaries. Our work illustrates the power of single-cell transcriptomics to decode the higher organizational principles of a tissue and may provide the initial chapter in a molecular encyclopaedia of the mammalian vasculature.
Goodwin, K;Lemma, B;Zhang, P;Boukind, A;Nelson, CM;
PMID: 36868232 | DOI: 10.1016/j.devcel.2023.02.002
It has been proposed that smooth muscle differentiation may physically sculpt airway epithelial branches in mammalian lungs. Serum response factor (SRF) acts with its co-factor myocardin to activate the expression of contractile smooth muscle markers. In the adult, however, smooth muscle exhibits a variety of phenotypes beyond contractile, and these are independent of SRF/myocardin-induced transcription. To determine whether a similar phenotypic plasticity is exhibited during development, we deleted Srf from the mouse embryonic pulmonary mesenchyme. Srf-mutant lungs branch normally, and the mesenchyme displays mechanical properties indistinguishable from controls. scRNA-seq identified an Srf-null smooth muscle cluster, wrapping the airways of mutant lungs, which lacks contractile smooth muscle markers but retains many features of control smooth muscle. Srf-null embryonic airway smooth muscle exhibits a synthetic phenotype, compared with the contractile phenotype of mature wild-type airway smooth muscle. Our findings identify plasticity in embryonic airway smooth muscle and demonstrate that a synthetic smooth muscle layer promotes airway branching morphogenesis.
Hua, SS;Ding, JJ;Sun, TC;Guo, C;Zhang, Y;Yu, ZH;Cao, YQ;Zhong, LH;Wu, Y;Guo, LY;Luo, JH;Cui, YH;Qiu, S;
PMID: 36842495 | DOI: 10.1016/j.biopsych.2023.02.013
The ventromedial prefrontal cortex (vmPFC) has been viewed as a locus to store and recall extinction memory. However, the synaptic and cellular mechanisms underlying this process remain elusive.We combined transgenic mice, electrophysiological recording, activity-dependent cell labeling, and chemogenetic manipulation to analyze the role of adaptor protein APPL1 in the vmPFC for fear extinction retrieval.We found that both constitutive and conditional APPL1 knockout decreases NMDA receptor (NMDAR) function in the vmPFC and impairs fear extinction retrieval. Moreover, APPL1 undergoes nuclear translocation during extinction retrieval. Blocking APPL1 nucleocytoplasmic translocation reduces NMDAR currents and disrupts extinction retrieval. We further identified a prefrontal neuronal ensemble that is both necessary and sufficient for the storage of extinction memory. Inducible APPL1 knockout in this ensemble abolishes NMDAR-dependent synaptic potentiation and disrupts extinction retrieval, while simultaneously chemogenetic activation of this ensemble rescues the impaired behaviors.Therefore, our results indicate that a prefrontal neuronal ensemble stores extinction memory, and APPL1 signaling supports these neurons to retrieve extinction memory via controlling NMDAR-dependent potentiation.
ACS chemical neuroscience
Dai, D;Li, W;Chen, A;Gao, XF;Xiong, L;
PMID: 35412792 | DOI: 10.1021/acschemneuro.2c00067
The lateral habenula (LHb) is a tiny structure that acts as a hub, relaying signals from the limbic forebrain structures and basal ganglia to the brainstem modulatory area. Facilitated by updated knowledge and more precise manipulation of circuits, the progress in figuring out the neural circuits and functions of the LHb has increased dramatically over the past decade. Importantly, LHb is found to play an integrative role and has profound effects on a variety of behaviors associated with pain, including depression-like and anxiety-like behaviors, antireward or aversion, aggression, defensive behavior, and substance use disorder. Thus, LHb is a potential target for improving pain management and related disorders. In this review, we focused on the functions, related circuits, and neurotransmissions of the LHb in pain processing and related behaviors. A comprehensive understanding of the relationship between the LHb and pain will help to find new pain treatments.
A neural circuit for excessive feeding driven by environmental context in mice
Mohammad, H;Senol, E;Graf, M;Lee, CY;Li, Q;Liu, Q;Yeo, XY;Wang, M;Laskaratos, A;Xu, F;Luo, SX;Jung, S;Augustine, GJ;Fu, Y;
PMID: 34168339 | DOI: 10.1038/s41593-021-00875-9
Despite notable genetic influences, obesity mainly results from the overconsumption of food, which arises from the interplay of physiological, cognitive and environmental factors. In patients with obesity, eating is determined more by external cues than by internal physiological needs. However, how environmental context drives non-homeostatic feeding is elusive. Here, we identify a population of somatostatin (TNSST) neurons in the mouse hypothalamic tuberal nucleus that are preferentially activated by palatable food. Activation of TNSST neurons enabled a context to drive non-homeostatic feeding in sated mice and required inputs from the subiculum. Pairing a context with palatable food greatly potentiated synaptic transmission between the subiculum and TNSST neurons and drove non-homeostatic feeding that could be selectively suppressed by inhibiting TNSST neurons or the subiculum but not other major orexigenic neurons. These results reveal how palatable food, through a specific hypothalamic circuit, empowers environmental context to drive non-homeostatic feeding.
Girbl T, Lenn T, Perez L, Rolas L, Barkaway A, Thiriot A, del Fresno C, Lynam E, Hub E, Thelen M, Graham G, Alon R, Sancho D, von Andrian UH, Voisin MB, Rot A, Nourshargh S.
PMID: 30446388 | DOI: 10.1016/j.immuni.2018.09.018
Neutrophils require directional cues to navigate through the complex structure of venular walls and into inflamed tissues. Here we applied confocal intravital microscopy to analyze neutrophil emigration in cytokine-stimulated mouse cremaster muscles. We identified differential and non-redundant roles for the chemokines CXCL1 and CXCL2, governed by their distinct cellular sources. CXCL1 was produced mainly by TNF-stimulated endothelial cells (ECs) and pericytes and supported luminal and sub-EC neutrophil crawling. Conversely, neutrophils were the main producers of CXCL2, and this chemokine was critical for correct breaching of endothelial junctions. This pro-migratory activity of CXCL2 depended on the atypical chemokine receptor 1 (ACKR1), which is enriched within endothelial junctions. Transmigrating neutrophils promoted a self-guided migration response through EC junctions, creating a junctional chemokine "depot" in the form of ACKR1-presented CXCL2 that enabled efficient unidirectional luminal-to-abluminal migration. Thus, CXCL1 and CXCL2 act in a sequential manner to guide neutrophils through venular walls as governed by their distinct cellular sources.
Frontiers in neuroendocrinology
Beekly, BG;Rupp, A;Burgess, CR;Elias, CF;
PMID: 37149229 | DOI: 10.1016/j.yfrne.2023.101069
Hypothalamic melanin-concentrating hormone (MCH) neurons participate in many fundamental neuroendocrine processes. While some of their effects can be attributed to MCH itself, others appear to depend on co-released neurotransmitters. Historically, the subject of fast neurotransmitter co-release from MCH neurons has been contentious, with data to support MCH neurons releasing GABA, glutamate, both, and neither. Rather than assuming a position in that debate, this review considers the evidence for all sides and presents an alternative explanation: neurochemical identity, including classical neurotransmitter content, is subject to change. With an emphasis on the variability of experimental details, we posit that MCH neurons may release GABA and/or glutamate at different points according to environmental and contextual factors. Through the lens of the MCH system, we offer evidence that the field of neuroendocrinology would benefit from a more nuanced and dynamic interpretation of neurotransmitter identity.
Angelozzi, M;Pellegrino da Silva, R;Gonzalez, MV;Lefebvre, V;
PMID: 35830813 | DOI: 10.1016/j.celrep.2022.111045
The mammalian skull vault is essential to shape the head and protect the brain, but the cellular and molecular events underlying its development remain incompletely understood. Single-cell transcriptomic profiling from early to late mouse embryonic stages provides a detailed atlas of cranial lineages. It distinguishes various populations of progenitors and reveals a high expression of SOXC genes (encoding the SOX4, SOX11, and SOX12 transcription factors) early in development in actively proliferating and myofibroblast-like osteodermal progenitors. SOXC inactivation in these cells causes severe skull and skin underdevelopment due to the limited expansion of cell populations before and upon lineage commitment. SOXC genes enhance the expression of gene signatures conferring dynamic cellular and molecular properties, including actin cytoskeleton assembly, chromatin remodeling, and signaling pathway induction and responsiveness. These findings shed light onto craniogenic mechanisms and SOXC functions and suggest that similar mechanisms could decisively control many developmental, adult, pathological, and regenerative processes.
