Lee SJ, Sanchez-Watts G, Krieger JP, Pignalosa A, Norell PN, Cortella A, Pettersen KG, Vrdoljak D, Hayes MR, Kanoski S, Langhans W, Watts AG.
PMID: - | DOI: 10.1016/j.molmet.2018.03.008
Abstract
Objective
Glucagon-like peptide-1 (GLP-1) neurons in the hindbrain densely innervate the dorsomedial hypothalamus (DMH), a nucleus strongly implicated in body weight regulation and the sympathetic control of brown adipose tissue (BAT) thermogenesis. Therefore, DMH GLP-1 receptors (GLP-1R) are well placed to regulate energy balance by controlling sympathetic outflow and BAT function.
Methods
We investigate this possibility in adult male rats by using direct administration of GLP-1 (0.5 ug) into the DMH, knocking down DMH GLP-1R mRNA with viral-mediated RNA interference, and by examining the neurochemical phenotype of GLP-1R expressing cells in the DMH using in situ hybridization.
Results
GLP-1 administered into the DMH increased BAT thermogenesis and hepatic triglyceride (TG) mobilization. On the other hand, Glp1r knockdown (KD) in the DMH increased body weight gain and adiposity, with a concomitant reduction in energy expenditure (EE), BAT temperature, and uncoupling protein 1 (UCP1) expression. Moreover, DMH Glp1r KD induced hepatic steatosis, increased plasma TG, and elevated liver specific de-novo lipogenesis, effects that collectively contributed to insulin resistance. Interestingly, DMH Glp1r KD increased neuropeptide Y (NPY) mRNA expression in the DMH. GLP-1R mRNA in the DMH, however, was found in GABAergic not NPY neurons, consistent with a GLP-1R-dependent inhibition of NPY neurons that is mediated by local GABAergic neurons. Finally, DMH Glp1r KD attenuated the anorexigenic effects of the GLP-1R agonist exendin-4, highlighting an important role of DMH GLP-1R signaling in GLP-1-based therapies.
Conclusions
Collectively, our data show that DMH GLP-1R signaling plays a key role for BAT thermogenesis and adiposity.
Arterioscler Thromb Vasc Biol.
Perisic Matic L, Rykaczewska U, Razuvaev A, Sabater-Lleal M, Lengquist M, Miller CL, Ericsson I, Röhl S, Kronqvist M, Aldi S, Magné J, Paloschi V, Vesterlund M, Li Y, Jin H, Diez MG, Roy J, Baldassarre D, Veglia F, Humphries SE, de Faire U, Tremoli E, Ode
PMID: 27470516 | DOI: 10.1161/ATVBAHA.116.307893
Abstract
OBJECTIVE:
Key augmented processes in atherosclerosis have been identified, whereas less is known about downregulated pathways. Here, we applied a systems biology approach to examine suppressed molecular signatures, with the hypothesis that they may provide insight into mechanisms contributing to plaque stability.
APPROACH AND RESULTS:
Muscle contraction, muscle development, and actin cytoskeleton were the most downregulated pathways (false discovery rate=6.99e-21, 1.66e-6, 2.54e-10, respectively) in microarrays from human carotid plaques (n=177) versus healthy arteries (n=15). In addition to typical smooth muscle cell (SMC) markers, these pathways also encompassed cytoskeleton-related genes previously not associated with atherosclerosis. SYNPO2, SYNM, LMOD1, PDLIM7, and PLN expression positively correlated to typical SMC markers in plaques (Pearson r>0.6, P<0.0001) and in rat intimal hyperplasia (r>0.8, P<0.0001). By immunohistochemistry, the proteins were expressed in SMCs in normal vessels, but largely absent in human plaques and intimal hyperplasia. Subcellularly, most proteins localized to the cytoskeleton in cultured SMCs and were regulated by active enhancer histone modification H3K27ac by chromatin immunoprecipitation-sequencing. Functionally, the genes were downregulated by PDGFB (platelet-derived growth factor beta) and IFNg (interferron gamma), exposure to shear flow stress, and oxLDL (oxidized low-density lipoprotein) loading. Genetic variants in PDLIM7, PLN, and SYNPO2 loci associated with progression of carotid intima-media thickness in high-risk subjects without symptoms of cardiovascular disease (n=3378). By eQTL (expression quantitative trait locus), rs11746443 also associated with PDLIM7 expression in plaques. Mechanistically, silencing of PDLIM7 in vitro led to downregulation of SMC markers and disruption of the actin cytoskeleton, decreased cell spreading, and increased proliferation.
CONCLUSIONS:
We identified a panel of genes that reflect the altered phenotype of SMCs in vascular disease and could be early sensitive markers of SMC dedifferentiation.
Chen YW, Das M, Oyarzabal EA, Cheng Q, Plummer NW, Smith KG, Jones GK, Malawsky D, Yakel JL, Shih YI, Jensen P.
PMID: 30214043 | DOI: 10.1038/s41380-018-0245-8
Noradrenergic signaling plays a well-established role in promoting the stress response. Here we identify a subpopulation of noradrenergic neurons, defined by developmental expression of Hoxb1, that has a unique role in modulating stress-related behavior. Using an intersectional chemogenetic strategy, in combination with behavioral and physiological analyses, we show that activation of Hoxb1-noradrenergic (Hoxb1-NE) neurons decreases anxiety-like behavior and promotes an active coping strategy in response to acute stressors. In addition, we use cerebral blood volume-weighted functional magnetic resonance imaging to show that chemoactivation of Hoxb1-NE neurons results in reduced activity in stress-related brain regions, including the bed nucleus of the stria terminalis, amygdala, and locus coeruleus. Thus, the actions of Hoxb1-NE neurons are distinct from the well-documented functions of the locus coeruleus in promoting the stress response, demonstrating that the noradrenergic system contains multiple functionally distinct subpopulations.
Hwang, E;Scarlett, JM;Baquero, AF;Bennett, C;Dong, Y;Chau, D;Brown, JM;Mercer, AJ;Meek, TH;Grove, KL;Phan, BAN;Morton, GJ;Williams, KW;Schwartz, MW;
PMID: 35917179 | DOI: 10.1172/jci.insight.160891
In rodent models of type 2 diabetes (T2D), central administration of fibroblast growth factor 1 (FGF1) normalizes elevated blood glucose levels in a manner that is sustained for weeks or months. Increased activity of NPY/AgRP neurons in the hypothalamic arcuate nucleus (ARC) is implicated in the pathogenesis of hyperglycemia in these animals, and the ARC is a key brain area for the antidiabetic action of FGF1. We therefore sought to determine whether FGF1 inhibits NPY/AgRP neurons, and if so whether this inhibitory effect is sufficiently durable to offer a feasible explanation for sustained diabetes remission induced by central administration of FGF1. Here we show that FGF1 inhibits ARC NPY/AgRP neuron activity, both after icv injection in vivo and when applied ex vivo in a slice preparation, and that the underlying mechanism involves increased input from presynaptic GABAergic neurons. Following central administration, the inhibitory effect of FGF1 on NPY/AgRP neurons is also highly durable, lasting for at least two weeks. To our knowledge, no precedent for such a prolonged inhibitory effect exists. Future studies are warranted to determine whether NPY/AgRP neuron inhibition contributes to the sustained antidiabetic action elicited by icv FGF1 injection in rodent models of T2D. .
Hultman K, Scarlett JM, Baquero AF, Cornea A, Zhang Y, Salinas CBG, Brown J, Morton GJ, Whalen EJ, Grove KL, Koegler FH, Schwartz MW, Mercer AJ.
PMID: 30809795 | DOI: 10.1002/cne.24668
Central activation of fibroblast growth factor (FGF) receptors regulates peripheral glucose homeostasis and reduces food intake in preclinical models of obesity and diabetes. The current work was undertaken to advance our understanding of the receptor expression, as sites of ligand action by FGF19, FGF21, and FGF1 in the mammalian brain remains unresolved. Recent advances in automated RNAscope in situ hybridization and droplet digital PCR (ddPCR) technology allowed us to interrogate central FGFR/beta klotho (Klb) system at the cellular level in the mouse, with relevant comparisons to nonhuman primate and human brain. FGFR1-3 gene expression was broadly distributed throughout the CNS in Mus musculus, with FGFR1 exhibiting the greatest heterogeneity. FGFR4 expression localized only in the medial habenula and subcommissural organ of mice. Likewise, Klb mRNA was restricted to the suprachiasmatic nucleus (SCh) and select midbrain and hindbrain nuclei. ddPCR in the rodent hypothalamus confirmed that, although expression levels are indeed low for Klb, there is nonetheless a bonafide subpopulation of Klb+ cells in the hypothalamus. In NHP and human midbrain and hindbrain, Klb + cells are quite rare, as is expression of FGFR4. Collectively, these data provide the most robust central map of the FGFR/Klb system to date and highlight central regions that may be of critical importance to assess central ligand effects with pharmacological dosing, such as the putative interactions between the endocrine FGFs and FGFR1/Klb, or FGF19 with FGFR4.
Nash, MJ;Dobrinskikh, E;Newsom, SA;Messaoudi, I;Janssen, RC;Aagaard, KM;McCurdy, CE;Gannon, M;Kievit, P;Friedman, JE;Wesolowski, SR;
PMID: 34935645 | DOI: 10.1172/jci.insight.154093
Maternal obesity affects nearly one-third of pregnancies and is a major risk factor for nonalcoholic fatty liver disease (NAFLD) in adolescent offspring, yet the mechanisms behind NAFLD remain poorly understood. Here, we demonstrate that nonhuman primate fetuses exposed to maternal Western-style diet (WSD) displayed increased fibrillar collagen deposition in the liver periportal region, with increased ACTA2 and TIMP1 staining, indicating localized hepatic stellate cell (HSC) and myofibroblast activation. This collagen deposition pattern persisted in 1-year-old offspring, despite weaning to a control diet (CD). Maternal WSD exposure increased the frequency of DCs and reduced memory CD4+ T cells in fetal liver without affecting systemic or hepatic inflammatory cytokines. Switching obese dams from WSD to CD before conception or supplementation of the WSD with resveratrol decreased fetal hepatic collagen deposition and reduced markers of portal triad fibrosis, oxidative stress, and fetal hypoxemia. These results demonstrate that HSCs and myofibroblasts are sensitive to maternal WSD-associated oxidative stress in the fetal liver, which is accompanied by increased periportal collagen deposition, indicative of early fibrogenesis beginning in utero. Alleviating maternal WSD-driven oxidative stress in the fetal liver holds promise for halting steatosis and fibrosis and preventing developmental programming of NAFLD.
CNS Neuroscience and Therapeutics
Grabon, W;Bodennec, J;Belmeguenai, A;Bezin, L;
: The endocannabinoid system is recognized as an important player in neuromodulation in the central nervous system (CNS). It comprises cannabinoid receptors, endogenous molecules called endocannabinoids (eCBs) that activate these receptors, and enzymes that synthesize and degrade eCBs. 1 The most abundant eCBs are anandamide and 2-arachidoylglycerol. Many effects of eCBs are mediated by type 1 (CB1R) and type 2 (CB2R) cannabinoid receptors, which are the best known and involved in the homeostatic control of several physiological functions in the brain and other organs. 2 CB1R and CB2R are G protein-coupled receptors (GPCRs) that, in addition to interacting with eCBs, are also activated by synthetic and plantderived cannabinoids. Both were cloned in the early 1990s from human leukemia cells. 3,4 However, it is important to note here that we must take a much broader view of this system. Indeed, studies over the last decade have revealed the existence of a wide range of lipid mediators with eCB-like properties, novel enzymes, and new receptors, effectively complicating our picture of the endocannabinoid system and justifying the use of endocannabinoidome to describe it. 5 CB1R is the most prevalent GPCR in the CNS and is expressed extensively by most neuron types. 6 This receptor is the major mediator of the psychoactive effects of Cannabis sativa and its derivatives.
International journal of molecular sciences
Torz, L;Niss, K;Lundh, S;Rekling, JC;Quintana, CD;Frazier, SED;Mercer, AJ;Cornea, A;Bertelsen, CV;Gerstenberg, MK;Hansen, AMK;Guldbrandt, M;Lykkesfeldt, J;John, LM;Villaescusa, JC;Petersen, N;
PMID: 35328681 | DOI: 10.3390/ijms23063260
Restoring the control of food intake is the key to obesity management and prevention. The arcuate nucleus (ARC) of the hypothalamus is extensively being studied as a potential anti-obesity target. Animal studies showed that neuropeptide FF (NPFF) reduces food intake by its action in neuropeptide Y (NPY) neurons of the hypothalamic ARC, but the detailed mode of action observed in human neurons is missing, due to the lack of a human-neuron-based model for pharmacology testing. Here, we validated and utilized a human-neural-stem-cell-based (hNSC) model of ARC to test the effects of NPFF on cellular pathways and neuronal activity. We found that in the human neurons, decreased cAMP levels by NPFF resulted in a reduced rate of cytoplasmic calcium oscillations, indicating an inhibition of ARC NPY neurons. This suggests the therapeutic potential of NPFFR2 in obesity. In addition, we demonstrate the use of human-stem-cell-derived neurons in pharmacological applications and the potential of this model to address functional aspects of human hypothalamic neurons.
Matsuo, J;Mon, N;Douchi, D;Yamamura, A;Kulkarni, M;Heng, D;Chen, S;Nuttonmanit, N;Li, Y;Yang, H;Lee, M;Tam, W;Osato, M;Chuang, L;Ito, Y;
| DOI: 10.1093/stmcls/sxab009
Mammary gland homeostasis is maintained by adult tissue stem-progenitor cells residing within the luminal and basal epithelia. Dysregulation of mammary stem cells is a key mechanism for cancer development. However, stem cell characterization is challenging because reporter models using cell-specific promoters do not fully recapitulate the mammary stem cell populations. We previously found that a 270-basepair Runx1 enhancer element, named eR1, marked stem cells in the blood and stomach. Here, we identified eR1 activity in a rare subpopulation of the ERα-negative luminal epithelium in mouse mammary glands. Lineage-tracing using an eR1-CreERT2 mouse model revealed that eR1+ luminal cells generated the entire luminal lineage and milk-secreting alveoli - eR1 therefore specifically marks lineage-restricted luminal stem cells. eR1-targeted-conditional knockout of Runx1 led to the expansion of luminal epithelial cells, accompanied by elevated ERα expression. Our findings demonstrate a definitive role for Runx1 in the regulation of the eR1-positive luminal stem cell proliferation during mammary homeostasis. Our findings identify a mechanistic link for Runx1 in stem cell proliferation and its dysregulation in breast cancer. Runx1 inactivation is therefore likely to be an early hit in the cell-of-origin of ERα+ luminal type breast cancer.
bioRxiv : the preprint server for biology
Zhang, W;Zhao, J;Deng, L;Ishimwe, N;Pauli, J;Wu, W;Shan, S;Kempf, W;Ballantyne, MD;Kim, D;Lyu, Q;Bennett, M;Rodor, J;Turner, AW;Lu, YW;Gao, P;Choi, M;Warthi, G;Kim, HW;Barroso, MM;Bryant, WB;Miller, CL;Weintraub, NL;Maegdefessel, L;Miano, JM;Baker, AH;Long, X;
PMID: 36711681 | DOI: 10.1101/2023.01.07.522948
Activation of vascular smooth muscle cells (VSMCs) inflammation is vital to initiate vascular disease. However, the role of human-specific long noncoding RNAs (lncRNAs) in VSMC inflammation is poorly understood.Bulk RNA-seq in differentiated human VSMCs revealed a novel human-specific lncRNA called IN flammatory M K L1 I nteracting L ong N oncoding RNA ( INKILN ). INKILN expression was assessed in multiple in vitro and ex vivo models of VSMC phenotypic modulation and human atherosclerosis and abdominal aortic aneurysm (AAA) samples. The transcriptional regulation of INKILN was determined through luciferase reporter system and chromatin immunoprecipitation assay. Both loss- and gain-of-function approaches and multiple RNA-protein and protein-protein interaction assays were utilized to uncover the role of INKILN in VSMC proinflammatory gene program and underlying mechanisms. Bacterial Artificial Chromosome (BAC) transgenic (Tg) mice were utilized to study INKLIN expression and function in ligation injury-induced neointimal formation.INKILN expression is downregulated in contractile VSMCs and induced by human atherosclerosis and abdominal aortic aneurysm. INKILN is transcriptionally activated by the p65 pathway, partially through a predicted NF-κB site within its proximal promoter. INKILN activates the proinflammatory gene expression in cultured human VSMCs and ex vivo cultured vessels. Mechanistically, INKILN physically interacts with and stabilizes MKL1, a key activator of VSMC inflammation through the p65/NF-κB pathway. INKILN depletion blocks ILIβ-induced nuclear localization of both p65 and MKL1. Knockdown of INKILN abolishes the physical interaction between p65 and MKL1, and the luciferase activity of an NF-κB reporter. Further, INKILN knockdown enhances MKL1 ubiquitination, likely through the reduced physical interaction with the deubiquitinating enzyme, USP10. INKILN is induced in injured carotid arteries and exacerbates ligation injury-induced neointimal formation in BAC Tg mice.These findings elucidate an important pathway of VSMC inflammation involving an INKILN /MKL1/USP10 regulatory axis. Human BAC Tg mice offer a novel and physiologically relevant approach for investigating human-specific lncRNAs under vascular disease conditions.
Proc Natl Acad Sci U S A. 2014 Nov 3.
Zhang HY, Gao M, Liu QR, Bi GH, Li X, Yang HJ, Gardner EL, Wu J, Xi ZX.
PMID: 25368177 | DOI: 201413210
Cannabinoid CB2 receptors (CB2Rs) have been recently reported to modulate brain dopamine (DA)-related behaviors; however, the cellular mechanisms underlying these actions are unclear. Here we report that CB2Rs are expressed in ventral tegmental area (VTA) DA neurons and functionally modulate DA neuronal excitability and DA-related behavior. In situ hybridization and immunohistochemical assays detected CB2 mRNA and CB2R immunostaining in VTA DA neurons. Electrophysiological studies demonstrated that activation of CB2Rs by JWH133 or other CB2R agonists inhibited VTA DA neuronal firing in vivo and ex vivo, whereas microinjections of JWH133 into the VTA inhibited cocaine self-administration. Importantly, all of the above findings observed in WT or CB1 -/- mice are blocked by CB2R antagonist and absent in CB2 -/- mice. These data suggest that CB2R-mediated reduction of VTA DA neuronal activity may underlie JWH133's modulation of DA-regulated behaviors.
Marinelli, S;Marrone, MC;Di Domenico, M;Marinelli, S;
PMID: 36222019 | DOI: 10.1002/glia.24281
Microglia, the innate immune cells of the central nervous system (CNS), execute their sentinel, housekeeping and defense functions through a panoply of genes, receptors and released cytokines, chemokines and neurotrophic factors. Moreover, microglia functions are closely linked to the constant communication with other cell types, among them neurons. Depending on the signaling pathway and type of stimuli involved, the outcome of microglia operation can be neuroprotective or neurodegenerative. Accordingly, microglia are increasingly becoming considered cellular targets for therapeutic intervention. Among signals controlling microglia activity, the endocannabinoid (EC) system has been shown to exert a neuroprotective role in many neurological diseases. Like neurons, microglia express functional EC receptors and can produce and degrade ECs. Interestingly, boosting EC signaling leads to an anti-inflammatory and neuroprotective microglia phenotype. Nonetheless, little evidence is available on the microglia-mediated therapeutic effects of EC compounds. This review focuses on the EC signals acting on the CNS microglia in physiological and pathological conditions, namely on the CB1R, CB2R and TRPV1-mediated regulation of microglia properties. It also provides new evidence, which strengthens the understanding of mechanisms underlying the control of microglia functions by ECs. Given the broad expression of the EC system in glial and neuronal cells, the resulting picture is the need for in vivo studies in transgenic mouse models to dissect the contribution of EC microglia signaling in the neuroprotective effects of EC-derived compounds.
