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.
Delineation of an insula-BNST circuit engaged by struggling behavior that regulates avoidance in mice
Luchsinger, JR;Fetterly, TL;Williford, KM;Salimando, GJ;Doyle, MA;Maldonado, J;Simerly, RB;Winder, DG;Centanni, SW;
PMID: 34117229 | DOI: 10.1038/s41467-021-23674-z
Active responses to stressors involve motor planning, execution, and feedback. Here we identify an insular cortex to BNST (insula→BNST) circuit recruited during restraint stress-induced active struggling that modulates affective behavior. We demonstrate that activity in this circuit tightly follows struggling behavioral events and that the size of the fluorescent sensor transient reports the duration of the struggle event, an effect that fades with repeated exposure to the homotypic stressor. Struggle events are associated with enhanced glutamatergic- and decreased GABAergic signaling in the insular cortex, indicating the involvement of a larger circuit. We delineate the afferent network for this pathway, identifying substantial input from motor- and premotor cortex, somatosensory cortex, and the amygdala. To begin to dissect these incoming signals, we examine the motor cortex input, and show that the cells projecting from motor regions to insular cortex are engaged shortly before struggle event onset. This study thus demonstrates a role for the insula→BNST pathway in monitoring struggling activity and regulating affective behavior.
Kupari J, Häring M, Agirre E, Castelo-Branco G, Ernfors P.
PMID: 31116992 | DOI: 10.1016/j.celrep.2019.04.096
Sensory functions of the vagus nerve are critical for conscious perceptions and for monitoring visceral functions in the cardio-pulmonary and gastrointestinal systems. Here, we present a comprehensive identification, classification, and validation of the neuron types in the neural crest (jugular) and placode (nodose) derived vagal ganglia by single-cell RNA sequencing (scRNA-seq) transcriptomic analysis. Our results reveal major differences between neurons derived from different embryonic origins. Jugular neurons exhibit fundamental similarities to the somatosensory spinal neurons, including major types, such as C-low threshold mechanoreceptors (C-LTMRs), A-LTMRs, Aδ-nociceptors, and cold-, and mechano-heat C-nociceptors. In contrast, the nodose ganglion contains 18 distinct types dedicated to surveying the physiological state of the internal body. Our results reveal a vast diversity of vagal neuron types, including many previously unanticipated types, as well as proposed types that are consistent with chemoreceptors, nutrient detectors, baroreceptors, and stretch and volume mechanoreceptors of the respiratory, gastrointestinal, and cardiovascular systems.
Sol�-Boldo L, Raddatz G, Sch�tz S, Mallm JP, Rippe K, Lonsdorf AS, Rodr�guez-Paredes M, Lyko F
PMID: 32327715 | DOI: 10.1038/s42003-020-0922-4
Fibroblasts are an essential cell population for human skin architecture and function. While fibroblast heterogeneity is well established, this phenomenon has not been analyzed systematically yet. We have used single-cell RNA sequencing to analyze the transcriptomes of more than 5,000 fibroblasts from a sun-protected area in healthy human donors. Our results define four main subpopulations that can be spatially localized and show differential secretory, mesenchymal and pro-inflammatory functional annotations. Importantly, we found that this fibroblast 'priming' becomes reduced with age. We also show that aging causes a substantial reduction in the predicted interactions between dermal fibroblasts and other skin cells, including undifferentiated keratinocytes at the dermal-epidermal junction. Our work thus provides evidence for a functional specialization of human dermal fibroblasts and identifies the partial loss of cellular identity as an important age-related change in the human dermis. These findings have important implications for understanding human skin aging and its associated phenotypes.
Jais A, Paeger L, Sotelo-Hitschfeld T, Bremser S, Prinzensteiner M, Klemm P, Mykytiuk V, Widdershooven PJM, Vesting AJ, Grzelka K, Min�re M, Cremer AL, Xu J, Korotkova T, Lowell BB, Zeilhofer HU, Backes H, Fenselau H, Wunderlich FT, Kloppenburg P, Br�ning JC
PMID: 32302532 | DOI: 10.1016/j.neuron.2020.03.022
Calorie-rich diets induce hyperphagia and promote obesity, although the underlying mechanisms remain poorly defined. We find that short-term high-fat-diet (HFD) feeding of mice activates prepronociceptin (PNOC)-expressing neurons in the arcuate nucleus of the hypothalamus (ARC). PNOCARC neurons represent a previously unrecognized GABAergic population of ARC neurons distinct from well-defined feeding regulatory AgRP or POMC neurons. PNOCARC neurons arborize densely in the ARC and provide inhibitory synaptic input to nearby anorexigenic POMC neurons. Optogenetic activation of PNOCARC neurons in the ARC and their projections to the bed nucleus of the stria terminalis promotes feeding. Selective ablation of these cells promotes the activation of POMC neurons upon HFD exposure, reduces feeding, and protects from obesity, but it does not affect food intake or body weight under normal chow consumption. We characterize PNOCARC neurons as a novel ARC neuron population activated upon palatable food consumption to promote hyperphagia
Kouvaros, S;Bizup, B;Solis, O;Kumar, M;Ventriglia, E;Curry, FP;Michaelides, M;Tzounopoulos, T;
PMID: 37294760 | DOI: 10.1126/sciadv.adf3525
Synaptic zinc is a neuromodulator that shapes synaptic transmission and sensory processing. The maintenance of synaptic zinc is dependent on the vesicular zinc transporter, ZnT3. Hence, the ZnT3 knockout mouse has been a key tool for studying the mechanisms and functions of synaptic zinc. However, the use of this constitutive knockout mouse has notable limitations, including developmental, compensatory, and brain and cell type specificity issues. To overcome these limitations, we developed and characterized a dual recombinase transgenic mouse, which combines the Cre and Dre recombinase systems. This mouse allows for tamoxifen-inducible Cre-dependent expression of exogenous genes or knockout of floxed genes in ZnT3-expressing neurons and DreO-dependent region and cell type-specific conditional ZnT3 knockout in adult mice. Using this system, we reveal a neuromodulatory mechanism whereby zinc release from thalamic neurons modulates N-methyl-d-aspartate receptor activity in layer 5 pyramidal tract neurons, unmasking previously unknown features of cortical neuromodulation.
Toenhake, CG;Voorberg-van der Wel, A;Wu, H;Kanyal, A;Nieuwenhuis, IG;van der Werff, NM;Hofman, SO;Zeeman, AM;Kocken, CHM;Bártfai, R;
PMID: 37392389 | DOI: 10.1016/j.celrep.2023.112727
Dormancy enables relapsing malaria parasites, such as Plasmodium vivax and cynomolgi, to survive unfavorable conditions. It is enabled by hypnozoites, parasites remaining quiescent inside hepatocytes before reactivating and establishing blood-stage infection. We integrate omics approaches to explore gene-regulatory mechanisms underlying hypnozoite dormancy. Genome-wide profiling of activating and repressing histone marks identifies a few genes that get silenced by heterochromatin during hepatic infection of relapsing parasites. By combining single-cell transcriptomics, chromatin accessibility profiling, and fluorescent in situ RNA hybridization, we show that these genes are expressed in hypnozoites and that their silencing precedes parasite development. Intriguingly, these hypnozoite-specific genes mainly encode proteins with RNA-binding domains. We hence hypothesize that these likely repressive RNA-binding proteins keep hypnozoites in a developmentally competent but dormant state and that heterochromatin-mediated silencing of the corresponding genes aids reactivation. Exploring the regulation and exact function of these proteins hence could provide clues for targeted reactivation and killing of these latent pathogens.
Li, L;Sun, Y;Davis, AE;Shah, SH;Hamed, LK;Wu, MR;Lin, CH;Ding, JB;Wang, S;
PMID: 37269288 | DOI: 10.1016/j.celrep.2023.112596
Neural progenitor cells lengthen their cell cycle to prime themselves for differentiation as development proceeds. It is currently not clear how they counter this lengthening and avoid being halted in the cell cycle. We show that N6-methyladenosine (m6A) methylation of cell-cycle-related mRNAs ensures the proper cell-cycle progression of late-born retinal progenitor cells (RPCs), which are born toward the end of retinogenesis and have long cell-cycle length. Conditional deletion of Mettl14, which is required for depositing m6A, led to delayed cell-cycle exit of late-born RPCs but has no effect on retinal development prior to birth. m6A sequencing and single-cell transcriptomics revealed that mRNAs involved in elongating the cell cycle were highly enriched for m6A, which could target them for degradation and guarantee proper cell-cycle progression. In addition, we identified Zfp292 as a target of m6A and potent inhibitor of RPC cell-cycle progression.
de la O, S;Yao, X;Chang, S;Liu, Z;Sneddon, JB;
PMID: 37178817 | DOI: 10.1016/j.molmet.2023.101735
Numerous studies have characterized the existence of cell subtypes, along with their corresponding transcriptional profiles, within the developing mouse pancreas. The upstream mechanisms that initiate and maintain gene expression programs across cell states, however, remain largely unknown. Here, we generate single-nucleus ATAC-Sequencing data of developing murine pancreas and perform an integrated, multi-omic analysis of both chromatin accessibility and RNA expression to describe the chromatin landscape of the developing pancreas at both E14.5 and E17.5 at single-cell resolution. We identify candidate transcription factors regulating cell fate and construct gene regulatory networks of active transcription factor binding to regulatory regions of downstream target genes. This work serves as a valuable resource for the field of pancreatic biology in general and contributes to our understanding of lineage plasticity among endocrine cell types. In addition, these data identify which epigenetic states should be represented in the differentiation of stem cells to the pancreatic beta cell fate to best recapitulate in vitro the gene regulatory networks that are critical for progression along the beta cell lineage in vivo.
González-García, I;García-Clavé, E;Cebrian-Serrano, A;Le Thuc, O;Contreras, RE;Xu, Y;Gruber, T;Schriever, SC;Legutko, B;Lintelmann, J;Adamski, J;Wurst, W;Müller, TD;Woods, SC;Pfluger, PT;Tschöp, MH;Fisette, A;García-Cáceres, C;
PMID: 36889283 | DOI: 10.1016/j.cmet.2023.02.004
Until menopause, women have a lower propensity to develop metabolic diseases than men, suggestive of a protective role for sex hormones. Although a functional synergy between central actions of estrogens and leptin has been demonstrated to protect against metabolic disturbances, the underlying cellular and molecular mechanisms mediating this crosstalk have remained elusive. By using a series of embryonic, adult-onset, and tissue/cell-specific loss-of-function mouse models, we document an unprecedented role of hypothalamic Cbp/P300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 1 (d1) in mediating estradiol (E2)-dependent leptin actions that control feeding specifically in pro-opiomelanocortin (Pomc) neurons. We reveal that within arcuate Pomc neurons, d1 drives leptin's anorectic effects by acting as a co-factor converging E2 and leptin signaling via direct d1-ERα-Stat3 interactions. Together, these results provide new insights on how melanocortin neurons integrate endocrine inputs from gonadal and adipose axes via d1, thereby contributing to the sexual dimorphism in diet-induced obesity.
Choi, M;Schneeberger, M;Fan, W;Bugde, A;Gautron, L;Vale, K;Hammer, RE;Zhang, Y;Friedman, JM;Mangelsdorf, DJ;Kliewer, SA;
PMID: 36889282 | DOI: 10.1016/j.cmet.2023.02.005
Animals that consume fermenting fruit and nectar are at risk of exposure to ethanol and the detrimental effects of inebriation. In this report, we show that the hormone FGF21, which is strongly induced by ethanol in murine and human liver, stimulates arousal from intoxication without changing ethanol catabolism. Mice lacking FGF21 take longer than wild-type littermates to recover their righting reflex and balance following ethanol exposure. Conversely, pharmacologic FGF21 administration reduces the time needed for mice to recover from ethanol-induced unconsciousness and ataxia. FGF21 did not counteract sedation caused by ketamine, diazepam, or pentobarbital, indicating specificity for ethanol. FGF21 mediates its anti-intoxicant effects by directly activating noradrenergic neurons in the locus coeruleus region, which regulates arousal and alertness. These results suggest that this FGF21 liver-brain pathway evolved to protect against ethanol-induced intoxication and that it might be targeted pharmaceutically for treating acute alcohol poisoning.
Subkhankulova, T;Camargo Sosa, K;Uroshlev, LA;Nikaido, M;Shriever, N;Kasianov, AS;Yang, X;Rodrigues, FSLM;Carney, TJ;Bavister, G;Schwetlick, H;Dawes, JHP;Rocco, A;Makeev, VJ;Kelsh, RN;
PMID: 36878908 | DOI: 10.1038/s41467-023-36876-4
Neural crest cells are highly multipotent stem cells, but it remains unclear how their fate restriction to specific fates occurs. The direct fate restriction model hypothesises that migrating cells maintain full multipotency, whilst progressive fate restriction envisages fully multipotent cells transitioning to partially-restricted intermediates before committing to individual fates. Using zebrafish pigment cell development as a model, we show applying NanoString hybridization single cell transcriptional profiling and RNAscope in situ hybridization that neural crest cells retain broad multipotency throughout migration and even in post-migratory cells in vivo, with no evidence for partially-restricted intermediates. We find that leukocyte tyrosine kinase early expression marks a multipotent stage, with signalling driving iridophore differentiation through repression of fate-specific transcription factors for other fates. We reconcile the direct and progressive fate restriction models by proposing that pigment cell development occurs directly, but dynamically, from a highly multipotent state, consistent with our recently-proposed Cyclical Fate Restriction model.
