scholarly journals Ghrelin Receptors Enhance Fat Taste Responsiveness in Female Mice

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1045
Author(s):  
Ashley N. Calder ◽  
Tian Yu ◽  
Naima S. Dahir ◽  
Yuxiang Sun ◽  
Timothy A. Gilbertson
Keyword(s):  
Fluorescent Protein ◽  
Critical Role ◽  
Taste Cell ◽  
Taste Perception ◽  
Cell Marker ◽  
Wild Type ◽  
Taste System ◽  
Growth Hormone Secretagogue ◽  
Ghrelin Receptor ◽  
Female Mice

Ghrelin is a major appetite-stimulating neuropeptide found in circulation. While its role in increasing food intake is well known, its role in affecting taste perception, if any, remains unclear. In this study, we investigated the role of the growth hormone secretagogue receptor’s (GHS-R; a ghrelin receptor) activity in the peripheral taste system using feeding studies and conditioned taste aversion assays by comparing wild-type and GHS-R-knockout models. Using transgenic mice expressing enhanced green fluorescent protein (GFP), we demonstrated GHS-R expression in the taste system in relation phospholipase C ß2 isotype (PLCβ2; type II taste cell marker)- and glutamate decarboxylase type 67 (GAD67; type III taste cell marker)-expressing cells using immunohistochemistry. We observed high levels of co-localization between PLCβ2 and GHS-R within the taste system, while GHS-R rarely co-localized in GAD67-expressing cells. Additionally, following 6 weeks of 60% high-fat diet, female Ghsr−/− mice exhibited reduced responsiveness to linoleic acid (LA) compared to their wild-type (WT) counterparts, while no such differences were observed in male Ghsr−/− and WT mice. Overall, our results are consistent with the interpretation that ghrelin in the taste system is involved in the complex sensing and recognition of fat compounds. Ghrelin-GHS-R signaling may play a critical role in the recognition of fatty acids in female mice, and this differential regulation may contribute to their distinct ingestive behaviors.

scholarly journals Ghrelin Amplifies Dopamine Signaling by Cross Talk Involving Formation of Growth Hormone Secretagogue Receptor/Dopamine Receptor Subtype 1 Heterodimers

2006 ◽  
Vol 20 (8) ◽  
pp. 1772-1785 ◽  
Author(s):  
Hong Jiang ◽  
Lorena Betancourt ◽  
Roy G. Smith
Keyword(s):  
Dopamine Receptor ◽  
Fluorescent Protein ◽  
Green Fluorescent Protein Fluorescence ◽  
Receptor Subtype ◽  
Protein Fluorescence ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ghrelin Receptor ◽  
Dopamine Signaling

Abstract Our objective is to determine the neuromodulatory role of ghrelin in the brain. To identify neurons that express the ghrelin receptor [GH secretagogue receptor (GHS-R)], we generated GHS-R-IRES-tauGFP mice by gene targeting. Neurons expressing the GHS-R exhibit green fluorescence and are clearly evident in the hypothalamus, hippocampus, cortex, and midbrain. Using immunohistochemistry in combination with green fluorescent protein fluorescence, we identified neurons that coexpress the dopamine receptor subtype 1 (D1R) and GHS-R. The potential physiological relevance of coexpression of these two receptors and the direct effect of ghrelin on dopamine signaling was investigated in vitro. Activation of GHS-R by ghrelin amplifies dopamine/D1R-induced cAMP accumulation. Intriguingly, amplification involves a switch in G protein coupling of the GHS-R from Gα11/q to Gαi/o by a mechanism consistent with agonist-dependent formation of GHS-R/D1R heterodimers. Most importantly, these results indicate that ghrelin has the potential to amplify dopamine signaling selectively in neurons that coexpress D1R and GHS-R.

scholarly journals TLR agonists regulate alloresponses and uncover a critical role for donor APCs in allogeneic bone marrow rejection

Blood ◽  
2008 ◽  
Vol 112 (8) ◽  
pp. 3508-3516 ◽  
Author(s):  
Patricia A. Taylor ◽  
Michael J. Ehrhardt ◽  
Christopher J. Lees ◽  
Angela Panoskaltsis-Mortari ◽  
Arthur M. Krieg ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dna Sequences ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Allogeneic Bone ◽  
Wild Type ◽  
Cpg Odns ◽  
Rejection Response ◽  
B Lineage ◽  
Green Fluorescent

Abstract Cytosine-phosphorothioate-guanine oligodeoxynucleotides (CpG ODNs) are synthetic ODNs with unmethylated DNA sequences that mimic viral and bacterial DNA and protect against infectious agents and tumor challenge. We show that CpG ODNs markedly accelerated graft-versus-host disease (GVHD) lethality by Toll-like receptor 9 (TLR9) ligation of host antigen-presenting cells (APCs), dependent upon host IFNγ but independent of host IL-12, IL-6, or natural killer (NK) cells. Imaging studies showed significantly more green fluorescent protein–positive (GFP+) effector T cells in lymphoid and nonlymphoid organs. In engraftment studies, CpG ODNs promoted allogeneic donor bone marrow (BM) rejection independent of host IFNγ, IL-12, or IL-6. During the course of these studies, we uncovered a previously unknown and critical role of donor BM APCs in modulating the rejection response. CpG ODNs promoted BM rejection by ligation of donor BM, but not host, TLR9. CpG ODNs did not impair engraftment of TLR9−/− BM unless wild-type myeloid (CD11b+) but not B-lineage (CD19+) BM cells were added to the donor inoculum. The importance of donor BM APCs in modulating the strength of the host antidonor rejection response was underscored by the finding that B7-1/B7-2−/− BM was less likely than wild-type BM to be rejected. Collectively, these data offer new insight into the mechanism of alloresponses regulating GVHD and BM rejection.

scholarly journals Keratocan and Lumican Regulate Neutrophil Infiltration and Corneal Clarity in Lipopolysaccharide-induced Keratitis by Direct Interaction with CXCL1

2007 ◽  
Vol 282 (49) ◽  
pp. 35502-35509 ◽  
Author(s):  
Eric C. Carlson ◽  
Michelle Lin ◽  
Chia-Yang Liu ◽  
Winston W-Y. Kao ◽  
Victor L. Perez ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Viral Vectors ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Corneal Thickness ◽  
Neutrophil Migration ◽  
Direct Interaction ◽  
Neutrophil Infiltration ◽  
Wild Type ◽  
Core Proteins

Keratocan and lumican are keratan-sulfate proteoglycans (KSPG), which have a critical role in maintaining corneal clarity. To determine whether these KSPGs have a role in corneal inflammation, we examined Kera–/– and Lum–/– mice in a model of lipopolysaccharide (LPS)-induced keratitis in which wild-type mice develop increased corneal thickness and haze due to neutrophil infiltration to the corneal stroma. Corneal thickness increases caused by LPS mice were significantly lower in Kera–/– and Lum–/– than wild-type mice. Further, LPS-injected Lum–/– mice had elevated corneal haze levels compared with that of Kera–/– and wild-type. At 24 h post-injection, total enhanced green fluorescent protein-positive bone marrow-derived inflammatory cells in chimeric mice was significantly lower in Kera–/– mice and Lum–/– mice compared with wild-type mice. Neutrophil infiltration was inhibited in Kera–/– and Lum–/– mice at 6 and 24 h post-stimulation, with Lum–/– corneas having the most profound defect in neutrophil migration. Reconstitution of keratocan and lumican expression in corneas of Kera–/– and Lum–/– mice using adeno-keratocan and adeno-lumican viral vectors, respectively, resulted in normal neutrophil infiltration in response to LPS. Immunoprecipitation/Western blot analysis showed that lumican and keratocan core proteins bind the CXC chemokine KC during a corneal inflammatory response, indicating that corneal KSPGs mediate neutrophil recruitment to the cornea by regulating chemokine gradient formation. Together, these data support a significant role for lumican and keratocan in a corneal inflammatory response with respect to edema, corneal clarity, and cellular infiltration.

scholarly journals A Novel Spore Protein, ExsM, Regulates Formation of the Exosporium in Bacillus cereus and Bacillus anthracis and Affects Spore Size and Shape

2010 ◽  
Vol 192 (15) ◽  
pp. 4012-4021 ◽  
Author(s):  
Monica M. Fazzini ◽  
Raymond Schuch ◽  
Vincent A. Fischetti
Keyword(s):  
Electron Microscopy ◽  
Bacillus Cereus ◽  
Bacillus Anthracis ◽  
Insertional Mutagenesis ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Basal Layer ◽  
Wild Type ◽  
Wide Range ◽  
Green Fluorescent

ABSTRACT Bacillus cereus spores are assembled with a series of concentric layers that protect them from a wide range of environmental stresses. The outermost layer, or exosporium, is a bag-like structure that interacts with the environment and is composed of more than 20 proteins and glycoproteins. Here, we identified a new spore protein, ExsM, from a β-mercaptoethanol extract of B. cereus ATCC 4342 spores. Subcellular localization of an ExsM-green fluorescent protein (GFP) protein revealed a dynamic pattern of fluorescence that follows the site of formation of the exosporium around the forespore. Under scanning electron microscopy, exsM null mutant spores were smaller and rounder than wild-type spores, which had an extended exosporium (spore length for the wt, 2.40 ± 0.56 μm, versus that for the exsM mutant, 1.66 ± 0.38 μm [P < 0.001]). Thin-section electron microscopy revealed that exsM mutant spores were encased by a double-layer exosporium, both layers of which were composed of a basal layer and a hair-like nap. Mutant exsM spores were more resistant to lysozyme treatment and germinated with higher efficiency than wild-type spores, and they had a delay in outgrowth. Insertional mutagenesis of exsM in Bacillus anthracis ΔSterne resulted in a partial second exosporium and in smaller spores. In all, these findings suggest that ExsM plays a critical role in the formation of the exosporium.

A STAT5 modifier locus on murine chromosome 7 modulates engraftment of hematopoietic stem cells during steady-state hematopoiesis

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1476-1483 ◽  
Author(s):  
Christine Couldrey ◽  
Heath L. Bradley ◽  
Kevin D. Bunting
Keyword(s):  
Stem Cells ◽  
Steady State ◽  
Hematopoietic Stem Cells ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Chromosome 7 ◽  
Wild Type ◽  
Genomic Locus ◽  
Hematopoietic Stem ◽  
Modifier Locus

AbstractHomologous disruption of expression of signal transducer and activator of transcription 5a (STAT5a) and STAT5b (STAT5ab–/–) in mice results in hematopoietic stem cells (HSCs) that can engraft irradiated hosts alone but are noncompetitive against wild-type HSCs. To explore mechanisms for this phenotype, we crossed the STAT5 mutations onto an HW80 background congenic to the original C57BL/6 that differs in a small chromosome 7 genomic locus. We previously demonstrated that C57BL/6 or HW80 background STAT5ab–/– bone marrow (BM) cells showed equal repopulating function either competitively or noncompetitively in irradiated hosts. However, one intraperitoneal injection of wild-type green fluorescent protein (GFP) transgenic BM cells into unconditioned newborn STAT5ab–/– recipients of either background was sufficient for high-level donor engraftment. Furthermore, haploinsufficiency of STAT5 (STAT5ab+/–) allowed improved engraftment over wild-type recipients, indicating a dose-dependent requirement for STAT5 activation. In reciprocal experiments, STAT5ab–/– BM was transplanted into nonirradiated W/Wv hosts. In these mice, C57BL/6 STAT5ab–/– BM cells were 10-fold more defective in long-term engraftment than control wild-type BM cells and HW80 STAT5ab–/– BM cells were 5- to 10-fold more defective than C57BL/6 STAT5ab–/– BM cells. Therefore, we conclude that STAT5 plays a critical role during steady-state HSC engraftment and a chromosome 7 modifier locus regulates this activity.

scholarly journals Recent Progress in the Study of Peroxiredoxin in the Harmful Algal Bloom Species Chattonella marina

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 162
Author(s):  
Yohei Shimasaki ◽  
Koki Mukai ◽  
Yuki Takai ◽  
Xuchun Qiu ◽  
Yuji Oshima
Keyword(s):  
Oxidative Stress ◽  
Growth Phase ◽  
Critical Role ◽  
High Irradiance ◽  
Growth Potential ◽  
Exponential Growth Phase ◽  
Wild Type ◽  
Chattonella Marina ◽  
Strong Light ◽  
Expression Strain

Peroxiredoxin (Prx) is a relatively recently discovered antioxidant enzyme family that scavenges peroxides and is known to be present in organisms from biological taxa ranging from bacteria to multicellular eukaryotes, including photosynthetic organisms. Although there have been many studies of the Prx family in higher plants, green algae, and cyanobacteria, few studies have concerned raphidophytes and dinoflagellates, which are among the eukaryotic algae that cause harmful algal blooms (HABs). In our proteomic study using 2-D electrophoresis, we found a highly expressed 2-Cys peroxiredoxin (2-CysPrx) in the raphidophyte Chattonella marina var. antiqua, a species that induces mass mortality of aquacultured fish. The abundance of the C. marina 2-CysPrx enzyme was highest in the exponential growth phase, during which photosynthetic activity was high, and it then decreased by about a factor of two during the late stationary growth phase. This pattern suggested that 2-CysPrx is a key enzyme involved in the maintenance of high photosynthesis activity. In addition, the fact that the depression of photosynthesis by excessively high irradiance was more severe in the 2-CysPrx low-expression strain (wild type) than in the normal-expression strain (wild type) of C. marina suggested that 2-CysPrx played a critical role in protecting the cell from oxidative stress caused by exposure to excessively high irradiance. In the field of HAB research, estimates of growth potential have been desired to predict the population dynamics of HABs for mitigating damage to fisheries. Therefore, omics approaches have recently begun to be applied to elucidate the physiology of the growth of HAB species. In this review, we describe the progress we have made using a molecular physiological approach to identify the roles of 2-CysPrx and other antioxidant enzymes in mitigating environmental stress associated with strong light and high temperatures and resultant oxidative stress. We also describe results of a survey of expressed Prx genes and their growth-phase-dependent behavior in C. marina using RNA-seq analysis. Finally, we speculate about the function of these genes and the ecological significance of 2-CysPrx, such as its involvement in circadian rhythms and the toxicity of C. marina to fish.

scholarly journals Cannabinoid-Induced Conditioned Place Preference, Intravenous Self-Administration, and Behavioral Stimulation Influenced by Ghrelin Receptor Antagonism in Rats

2021 ◽  
Vol 22 (5) ◽  
pp. 2397
Author(s):  
Chrysostomos Charalambous ◽  
Tereza Havlickova ◽  
Marek Lapka ◽  
Nina Puskina ◽  
Romana Šlamberová ◽  
...  
Keyword(s):  
Conditioned Place Preference ◽  
Fixed Ratio ◽  
Place Preference ◽  
Self Administration ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ghrelin Receptor ◽  
Addiction Therapy ◽  
Significant Efficacy ◽  
Lever Pressing

Cannabis/cannabinoids are widely used for recreational and therapy purposes, but their risks are largely disregarded. However, cannabinoid-associated use disorders and dependence are alarmingly increasing and an effective treatment is lacking. Recently, the growth hormone secretagogue receptor (GHSR1A) antagonism was proposed as a promising mechanism for drug addiction therapy. However, the role of GHS-R1A and its endogenous ligand ghrelin in cannabinoid abuse remains unclear. Therefore, the aim of our study was to investigate whether the GHS-R1A antagonist JMV2959 could reduce the tetrahydrocannabinol (THC)-induced conditioned place preference (CPP) and behavioral stimulation, the WIN55,212-2 intravenous self-administration (IVSA), and the tendency to relapse. Following an ongoing WIN55,212-2 self-administration, JMV2959 3 mg/kg was administered intraperitoneally 20 min before three consequent daily 120-min IVSA sessions under a fixed ratio FR1, which significantly reduced the number of the active lever-pressing, the number of infusions, and the cannabinoid intake. Pretreatment with JMV2959 suggested reduction of the WIN55,212-2-seeking/relapse-like behavior tested in rats on the twelfth day of the forced abstinence period. On the contrary, pretreatment with ghrelin significantly increased the cannabinoid IVSA as well as enhanced the relapse-like behavior. Co-administration of ghrelin with JMV2959 abolished/reduced the significant efficacy of the GHS-R1A antagonist in the cannabinoid IVSA. Pretreatment with JMV2959 significantly and dose-dependently reduced the manifestation of THC-induced CPP. The THC-CPP development was reduced after the simultaneous administration of JMV2959 with THC during conditioning. JMV2959 also significantly reduced the THC-induced behavioral stimulation in the LABORAS cage. Our findings suggest that GHS-R1A importantly participates in the rewarding/reinforcing effects of cannabinoids.

scholarly journals The critical role of T cells in glucocorticoid-induced osteoporosis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Lin Song ◽  
Lijuan Cao ◽  
Rui Liu ◽  
Hui Ma ◽  
Yanan Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
Side Effects ◽  
Critical Role ◽  
Wild Type ◽  
Receptor Activator ◽  
Steady State Levels ◽  
Induced Apoptosis

AbstractGlucocorticoids (GC) are widely used clinically, despite the presence of significant side effects, including glucocorticoid-induced osteoporosis (GIOP). While GC are believed to act directly on osteoblasts and osteoclasts to promote osteoporosis, the detailed underlying molecular mechanism of GC-induced osteoporosis is still not fully elucidated. Here, we show that lymphocytes play a pivotal role in regulating GC-induced osteoporosis. We show that GIOP could not be induced in SCID mice that lack T cells, but it could be re-established by adoptive transfer of splenic T cells from wild-type mice. As expected, T cells in the periphery are greatly reduced by GC; instead, they accumulate in the bone marrow where they are protected from GC-induced apoptosis. These bone marrow T cells in GC-treated mice express high steady-state levels of NF-κB receptor activator ligand (RANKL), which promotes the formation and maturation of osteoclasts and induces osteoporosis. Taken together, these findings reveal a critical role for T cells in GIOP.

scholarly journals Mechanism of Aurora-B Degradation and Its Dependency on Intact KEN and A-Boxes: Identification of an Aneuploidy-Promoting Property

2005 ◽  
Vol 25 (12) ◽  
pp. 4977-4992 ◽  
Author(s):  
Hao G. Nguyen ◽  
Dharmaraj Chinnappan ◽  
Takeshi Urano ◽  
Katya Ravid
Keyword(s):  
Chromosome Segregation ◽  
Fluorescent Protein ◽  
Point Mutations ◽  
Degradation Pathway ◽  
Aurora B ◽  
Stable Form ◽  
Wild Type ◽  
Green Fluorescent ◽  
Critical Regions

ABSTRACT The kinase Aurora-B, a regulator of chromosome segregation and cytokinesis, is highly expressed in a variety of tumors. During the cell cycle, the level of this protein is tightly controlled, and its deregulated abundance is suspected to contribute to aneuploidy. Here, we provide evidence that Aurora-B is a short-lived protein degraded by the proteasome via the anaphase-promoting cyclosome complex (APC/c) pathway. Aurora-B interacts with the APC/c through the Cdc27 subunit, Aurora-B is ubiquitinated, and its level is increased upon treatment with inhibitors of the proteasome. Aurora-B binds in vivo to the degradation-targeting proteins Cdh1 and Cdc20, the overexpression of which accelerates Aurora-B degradation. Using deletions or point mutations of the five putative degradation signals in Aurora-B, we show that degradation of this protein does not depend on its D-boxes (RXXL), but it does require intact KEN boxes and A-boxes (QRVL) located within the first 65 amino acids. Cells transfected with wild-type or A-box-mutated or KEN box-mutated Aurora-B fused to green fluorescent protein display the protein localized to the chromosomes and then to the midzone during mitosis, but the mutated forms are detected at greater intensities. Hence, we identified the degradation pathway for Aurora-B as well as critical regions for its clearance. Intriguingly, overexpression of a stable form of Aurora-B alone induces aneuploidy and anchorage-independent growth.

scholarly journals Subfertility in androgen-insensitive female mice is rescued by transgenic FSH

2017 ◽  
Vol 29 (7) ◽  
pp. 1426 ◽  
Author(s):  
K. A. Walters ◽  
M. C. Edwards ◽  
M. Jimenez ◽  
D. J. Handelsman ◽  
C. M. Allan
Keyword(s):  
Androgen Receptor ◽  
Litter Size ◽  
Ovarian Function ◽  
Reproductive Function ◽  
Antral Follicle ◽  
Female Fertility ◽  
Wild Type ◽  
Female Reproduction ◽  
Androgen Insensitivity ◽  
Female Mice

Androgens synergise with FSH in female reproduction but the nature of their interaction in ovarian function and fertility is not clear. In the present study, we investigated this interaction, notably whether higher endogenous FSH can overcome defective androgen actions in androgen receptor (AR)-knockout (ARKO) mice. We generated and investigated the reproductive function of mutant mice exhibiting AR resistance with or without expression of human transgenic FSH (Tg-FSH). On the background of inactivated AR signalling, which alone resulted in irregular oestrous cycles and reduced pups per litter, ovulation rates and antral follicle health, Tg-FSH expression restored follicle health, ovulation rates and litter size to wild-type levels. However, Tg-FSH was only able to partially rectify the abnormal oestrous cycles observed in ARKO females. Hence, elevated endogenous FSH rescued the intraovarian defects, and partially rescued the extraovarian defects due to androgen insensitivity. In addition, the observed increase in litter size in Tg-FSH females was not observed in the presence of AR signalling inactivation. In summary, the findings of the present study reveal that FSH can rescue impaired female fertility and ovarian function due to androgen insensitivity in female ARKO mice by maintaining follicle health and ovulation rates, and thereby optimal female fertility.

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