scholarly journals GDF15 in Appetite and Exercise: Essential Player or Coincidental Bystander?

Endocrinology ◽  
2021 ◽  
Author(s):  
Anders B Klein ◽  
Maximilian Kleinert ◽  
Erik A Richter ◽  
Christoffer Clemmensen
Keyword(s):  
Body Weight ◽  
Cell Types ◽  
Metformin Treatment ◽  
Growth Differentiation Factor 15 ◽  
Disease States ◽  
Stress Signal ◽  
Exogenous Agents ◽  
Potential Impact ◽  
Exercise Induced ◽  
Circulating Levels

Abstract Growth differentiation factor 15 (GDF15) has recently moved to the forefront of metabolism research. When administered pharmacologically, GDF15 reduces food intake and lowers body weight via the hindbrain-situated receptor GFRAL (glial cell-derived neurotrophic factor family receptor alpha like). Endogenous GDF15 is a ubiquitous cellular stress signal that can be produced and secreted by a variety of cell types. Circulating levels are elevated in a series of disease states, but also in response to exogenous agents such as metformin, colchicine, AICAR and cisplatin. Recently, exercise has emerged as a relevant intervention to interrogate GDF15 physiology. Prolonged endurance exercise increases circulating GDF15 to levels otherwise associated with certain pathological states and in response to metformin treatment. Yet, the jury is still out as to whether GDF15 is a functional ‘exerkine’ mediating organ-to-brain cross-talk or whether it is a coincidental bystander. In this review, we discuss the putative physiological implication of exercise-induced GDF15, focusing on the potential impact on appetite and metabolism.

scholarly journals Differential Effects of Toll-Like Receptor Activation and Differential Mediation by MAP Kinases of Immune Responses in Microglial Cells

2021 ◽  
Author(s):  
Jaedeok Kwon ◽  
Christos Arsenis ◽  
Maria Suessmilch ◽  
Alison McColl ◽  
Jonathan Cavanagh ◽  
...  
Keyword(s):  
Map Kinase ◽  
Microglial Activation ◽  
Map Kinases ◽  
Mrna Level ◽  
Cell Types ◽  
Receptor Activation ◽  
Microglial Cells ◽  
Toll Like Receptor ◽  
Disease States ◽  
Nitrite Production

AbstractMicroglial activation is believed to play a role in many psychiatric and neurodegenerative diseases. Based largely on evidence from other cell types, it is widely thought that MAP kinase (ERK, JNK and p38) signalling pathways contribute strongly to microglial activation following immune stimuli acting on toll-like receptor (TLR) 3 or TLR4. We report here that exposure of SimA9 mouse microglial cell line to immune mimetics stimulating TLR4 (lipopolysaccharide—LPS) or TLR7/8 (resiquimod/R848), results in marked MAP kinase activation, followed by induction of nitric oxide synthase, and various cytokines/chemokines. However, in contrast to TLR4 or TLR7/8 stimulation, very few effects of TLR3 stimulation by poly-inosine/cytidine (polyI:C) were detected. Induction of chemokines/cytokines at the mRNA level by LPS and resiquimod were, in general, only marginally affected by MAP kinase inhibition, and expression of TNF, Ccl2 and Ccl5 mRNAs, along with nitrite production, were enhanced by p38 inhibition in a stimulus-specific manner. Selective JNK inhibition enhanced Ccl2 and Ccl5 release. Many distinct responses to stimulation of TLR4 and TLR7 were observed, with JNK mediating TNF protein induction by the latter but not the former, and suppressing Ccl5 release by the former but not the latter. These data reveal complex modulation by MAP kinases of microglial responses to immune challenge, including a dampening of some responses. They demonstrate that abnormal levels of JNK or p38 signalling in microglial cells will perturb their profile of cytokine and chemokine release, potentially contributing to abnormal inflammatory patterns in CNS disease states.

A 24‐month metformin treatment study of children with obesity: Changes in circulating GDF ‐15 and associations with changes in body weight and visceral fat

2021 ◽  
Author(s):  
Gemma Carreras‐Badosa ◽  
Ariadna Gómez‐Vilarrubla ◽  
Berta Mas‐Parés ◽  
José‐María Martínez‐Calcerrada ◽  
Silvia Xargay‐Torrent ◽  
...  
Keyword(s):  
Body Weight ◽  
Visceral Fat ◽  
Metformin Treatment

Abstract MP11: Circulating Plasma Biomarkers Associated With Brain Arteriovenous Malformations

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Sarah E Wetzel-Strong ◽  
Shantel M Weinsheimer ◽  
Jeffrey Nelson ◽  
Ludmila Pawlikowska ◽  
Dewi Clark ◽  
...  
Keyword(s):  
Multiple Testing ◽  
Statistical Significance ◽  
Protein Profiling ◽  
P Value ◽  
P Values ◽  
Plasma Biomarkers ◽  
Standard Curve ◽  
Disease States ◽  
Heparin Plasma ◽  
Circulating Levels

Objective: Circulating plasma protein profiling may aid in the identification of cerebrovascular disease signatures. This study aimed to identify circulating angiogenic and inflammatory biomarkers that may serve as biomarkers to differentiate sporadic brain arteriovenous malformation (bAVM) patients from other conditions with brain AVMs, including hereditary hemorrhagic telangiectasia (HHT) patients. Methods: The Quantibody Human Angiogenesis Array 1000 (Raybiotech) is an ELISA multiplex panel that was used to assess the levels of 60 proteins related to angiogenesis and inflammation in heparin plasma samples from 13 sporadic unruptured bAVM patients (69% male, mean age 51 years) and 37 patients with HHT (40% male, mean age 47 years, n=19 (51%) with bAVM). The Quantibody Q-Analyzer tool was used to calculate biomarker concentrations based on the standard curve for each marker and log-transformed marker levels were evaluated for associations between disease states using a multivariable interval regression model adjusted for age, sex, ethnicity and collection site. Statistical significance was based on Bonferroni correction for multiple testing of 60 biomarkers (P< 8.3x10 - 4 ). Results: Circulating levels of two plasma proteins differed significantly between sporadic bAVM and HHT patients: PDGF-BB (P=2.6x10 -4 , PI= 3.37, 95% CI:1.76-6.46) and CCL5 (P=6.0x10 -6 , PI=3.50, 95% CI=2.04-6.03). When considering markers with a nominal p-value of less than 0.01, MMP1 and angiostatin levels also differed between patients with sporadic bAVM and HHT. Markers with nominal p-values less than 0.05 when comparing sporadic brain AVM and HHT patients also included angiostatin, IL2, VEGF, GRO, CXCL16, ITAC, and TGFB3. Among HHT patients, the circulating levels of UPAR and IL6 were elevated in patients with documented bAVMs when considering markers with nominal p-values less than 0.05. Conclusions: This study identified differential expression of two promising plasma biomarkers that differentiate sporadic bAVMs from patients with HHT. Furthermore, this study allowed us to evaluate markers that are associated with the presence of bAVMs in HHT patients, which may offer insight into mechanisms underlying bAVM pathophysiology.

Skeletal muscle adaptations to exercise are not influenced by metformin treatment in humans: secondary analyses of two randomised, clinical trials.

2021 ◽  
Author(s):  
Nanna Skytt Pilmark ◽  
Laura Oberholzer ◽  
Jens Frey Halling ◽  
Jonas M. Kristensen ◽  
Christina Pedersen Bønding ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Human Skeletal Muscle ◽  
Acute Exercise ◽  
Metformin Treatment ◽  
Ampk Activation ◽  
Double Blind ◽  
Parallel Group ◽  
Exercise Induced

Metformin and exercise both improve glycemic control, but in vitro studies have indicated that an interaction between metformin and exercise occurs in skeletal muscle, suggesting a blunting effect of metformin on exercise training adaptations. Two studies (a double-blind, parallel-group, randomized clinical trial conducted in 29 glucose-intolerant individuals and a double-blind, cross-over trial conducted in 15 healthy lean males) were included in this paper. In both studies, the effect of acute exercise +/- metformin treatment on different skeletal muscle variables, previously suggested to be involved in a pharmaco-physiological interaction between metformin and exercise, was assessed. Furthermore, in the parallel-group trial, the effect of 12 weeks of exercise training was assessed. Skeletal muscle biopsies were obtained before and after acute exercise and 12 weeks of exercise training, and mitochondrial respiration, oxidative stress and AMPK activation was determined. Metformin did not significantly affect the effects of acute exercise or exercise training on mitochondrial respiration, oxidative stress or AMPK activation, indicating that the response to acute exercise and exercise training adaptations in skeletal muscle is not affected by metformin treatment. Further studies are needed to investigate whether an interaction between metformin and exercise is present in other tissues, e.g. the gut. Trial registration: ClinicalTrials.gov (NCT03316690 and NCT02951260). Novelty bullets • Metformin does not affect exercise-induced alterations in mitochondrial respiratory capacity in human skeletal muscle • Metformin does not affect exercise-induced alterations in systemic levels of oxidative stress nor emission of reactive oxygen species from human skeletal muscle • Metformin does not affect exercise-induced AMPK activation in human skeletal muscle

scholarly journals Silencing of Unintegrated Retroviral DNAs

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2248
Author(s):  
Stephen P. Goff
Keyword(s):  
Embryonic Stem ◽  
Cell Types ◽  
Retroviral Infection ◽  
Double Stranded Dna ◽  
Immunodeficiency Virus ◽  
Unintegrated Dna ◽  
Potential Impact ◽  
Leukemia Viruses ◽  
Present Understanding

Retroviral infection delivers an RNA genome into the cytoplasm that serves as the template for the synthesis of a linear double-stranded DNA copy by the viral reverse transcriptase. Within the nucleus this linear DNA gives rise to extrachromosomal circular forms, and in a key step of the life cycle is inserted into the host genome to form the integrated provirus. The unintegrated DNA forms, like those of DNAs entering cells by other means, are rapidly loaded with nucleosomes and heavily silenced by epigenetic histone modifications. This review summarizes our present understanding of the silencing machinery for the DNAs of the mouse leukemia viruses and human immunodeficiency virus type 1. We consider the potential impact of the silencing on virus replication, on the sensing of the virus by the innate immune system, and on the formation of latent proviruses. We also speculate on the changeover to high expression from the integrated proviruses in permissive cell types, and briefly consider the silencing of proviruses even after integration in embryonic stem cells and other developmentally primitive cell types.

scholarly journals Exercise, weight loss, and changes in body composition in mice: phenotypic relationships and genetic architecture

2011 ◽  
Vol 43 (4) ◽  
pp. 199-212 ◽  
Author(s):  
Scott A. Kelly ◽  
Derrick L. Nehrenberg ◽  
Kunjie Hua ◽  
Theodore Garland ◽  
Daniel Pomp
Keyword(s):  
Weight Loss ◽  
Body Composition ◽  
Body Weight ◽  
Food Consumption ◽  
Genetic Architecture ◽  
Interval Mapping ◽  
Voluntary Exercise ◽  
Exercise Induced ◽  
Running Wheels ◽  
The Relationship

The regulation of body weight and composition is complex, simultaneously affected by genetic architecture, the environment, and their interactions. We sought to analyze the complex phenotypic relationships between voluntary exercise, food consumption, and changes in body weight and composition and simultaneously localize quantitative trait loci (QTL) controlling these traits. A large ( n = 815) murine advanced intercross line (G4) was created from a reciprocal cross between a high-running line and the inbred strain C57BL/6J. Body weight and composition (% fat, % lean) were measured at 4, 6, and 8 wk of age. After measurements at 8 wk of age, mice were given access to running wheels, during which food consumption was quantified and after which body weight and composition were assessed to evaluate exercise-induced changes. Phenotypic correlations indicated that the relationship between exercise and overall change in weight and adiposity depended on body composition before the initiation of exercise. Interval mapping revealed QTL for body weight, % fat, and % lean at 4, 6, and 8 wk of age. Furthermore, QTL were observed for food consumption and changes in weight, % fat, and % lean in response to short-term exercise. Here we provide some clarity for the relationship between weight loss, reduction in adiposity, food consumption, and exercise. Simultaneously, we reinforce the genetic basis for body weight and composition with some independent loci controlling growth at different ages. Finally, we present unique QTL providing insight regarding variation in weight loss and reduction in adiposity in response to exercise.

Abstract 1433: The Cardioregulatory Peptide Apelin is Preferentially Expressed by Endothelial Cells and Upregulated in Myocardial Disease States

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Ramendra K Kundu ◽  
Ahmad Y Sheikh ◽  
Michael Y Ho ◽  
Hyung J Chun ◽  
Diem T Huynh ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Reporter Gene ◽  
Fold Increase ◽  
Cell Types ◽  
Heart Tissue ◽  
Capillary Endothelium ◽  
Lacz Gene ◽  
Lacz Reporter ◽  
Rt Pcr ◽  
Disease States

Introduction: The APJ receptor and its ligand, apelin, comprise a homeostatic, cardio-regulatory pathway. Although cardiac apelin expression levels are altered in humans with cardiac failure, the cell type responsible for apelin expression and modulation in disease states remains unknown. Hypothesis: Apelin production is restricted to the endothelial compartment and is upregulated in states of cardiovascular stress. Methods: Transgenic apelin-LacZ reporter mice (SVJ background) were created by insertion of the nuclear localizing bacterial LacZ gene immediately downstream of the apelin promoter. Mice (n=12) were randomized to left anterior descending coronary artery (LAD) ligation, thoracic aortic constriction (TAC) or sham groups. Hearts were harvested 3 and 8 weeks post-TAC or LAD ligation, respectively. Localization of apelin expression was determined by Xgal staining. Endothelial phenotype of lacZ positive cells was confirmed by CD31 co-staining. Apelin expressing cells were quantified by histology. Apelin reporter results were confirmed by quantitating apelin expression in WT animals following LAD ligation (n=11) or sham (n=11) procedure by RT-PCR. Results: Extensive immunohistochemistry studies of heart tissue revealed lacZ reporter gene expression to be restricted to the coronary venous and capillary endothelium, with no expression by cardiomyocytes. Following both LAD ligation and TAC, the number of LacZ-apelin (+) endothelial cells significantly increased (p<0.002) in all chambers of the heart (Table ), with no evidence of apelin expression by other cell types. Evaluation of WT hearts by RT-PCR for the apelin gene confirmed the reporter gene findings with 1.3±0.3 fold increase (p<0.05) of apelin expression induced by LAD ligation compared to sham. Conclusions: Apelin is primary expressed by endothelial cells within the heart and is upregulated in response to myocardial stress. Apelin-LacZ Expressing Endothelial Cells are Increased Following Myocardial Injury

scholarly journals A randomized controlled trial of metformin on left ventricular hypertrophy in patients with coronary artery disease without diabetes: the MET-REMODEL trial

2019 ◽  
Vol 40 (41) ◽  
pp. 3409-3417 ◽  
Author(s):  
Mohapradeep Mohan ◽  
Shaween Al-Talabany ◽  
Angela McKinnie ◽  
Ify R Mordi ◽  
Jagdeep S S Singh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Coronary Artery Disease ◽  
Body Weight ◽  
Coronary Artery ◽  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Left Ventricular ◽  
Haemoglobin A1c ◽  
Metformin Treatment ◽  
Artery Disease

Abstract Aim We tested the hypothesis that metformin may regress left ventricular hypertrophy (LVH) in patients who have coronary artery disease (CAD), with insulin resistance (IR) and/or pre-diabetes. Methods and results We randomly assigned 68 patients (mean age 65 ± 8 years) without diabetes who have CAD with IR and/or pre-diabetes to receive either metformin XL (2000 mg daily dose) or placebo for 12 months. Primary endpoint was change in left ventricular mass indexed to height1.7 (LVMI), assessed by magnetic resonance imaging. In the modified intention-to-treat analysis (n = 63), metformin treatment significantly reduced LVMI compared with placebo group (absolute mean difference −1.37 (95% confidence interval: −2.63 to −0.12, P = 0.033). Metformin also significantly reduced other secondary study endpoints such as: LVM (P = 0.032), body weight (P = 0.001), subcutaneous adipose tissue (P = 0.024), office systolic blood pressure (BP, P = 0.022) and concentration of thiobarbituric acid reactive substances, a biomarker for oxidative stress (P = 0.04). The glycated haemoglobin A1C concentration and fasting IR index did not differ between study groups at the end of the study. Conclusion Metformin treatment significantly reduced LVMI, LVM, office systolic BP, body weight, and oxidative stress. Although LVH is a good surrogate marker of cardiovascular (CV) outcome, conclusive evidence for the cardio-protective role of metformin is required from large CV outcomes trials.

scholarly journals DLK1 Expressed in Mouse Orexin Neurons Modulates Anxio-Depressive Behavior but Not Energy Balance

2020 ◽  
Vol 10 (12) ◽  
pp. 975
Author(s):  
Tatiyana Harris ◽  
Raluca Bugescu ◽  
Jaylyn Kelly ◽  
Anna Makela ◽  
Morgan Sotzen ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Balance ◽  
Ingestive Behavior ◽  
Hypothalamic Area ◽  
Disease States ◽  
Adult Mice ◽  
Plus Maze ◽  
And Behavior ◽  
Physiologic Role

Lateral hypothalamic area (LHA) neurons expressing the neuropeptide orexin (OX) are implicated in obesity and anxio-depression. However, these neurons release OX as well as a host of other proteins that might contribute to normal physiology and disease states. We hypothesized that delta-like homolog 1 (DLK1), a protein reported to be co-expressed by all OX neurons, contributes to the regulation of energy balance and/or anxio-depression. Consistent with previous reports, we found that all rat OX neurons co-express DLK1. Yet, in mice and humans only a subset of OX neurons co-expressed DLK1. Since human OX-DLK1 distribution is more similar to mice than rats, mice are a comparable model to assess the human physiologic role of DLK1. We therefore used a viral lesion strategy to selectively delete DLK1 within the LHA of adult mice (DLK1Null) to reveal its role in body weight and behavior. Adult-onset DLK1 deletion had no impact on body weight or ingestive behavior. However, DLK1Null mice engaged in more locomotor activity than control mice and had decreased anxiety and depression measured via the elevated plus maze and forced swim tests. These data suggest that DLK1 expression via DLK1-expressing OX neurons primarily contributes to anxio-depression behaviors without impacting body weight.

scholarly journals Emerging role of extracellular vesicles in liver diseases

2019 ◽  
Vol 317 (5) ◽  
pp. G739-G749 ◽  
Author(s):  
Harmeet Malhi
Keyword(s):  
Extracellular Vesicles ◽  
Cell Communication ◽  
Cell Types ◽  
Cell Responses ◽  
Therapeutic Delivery ◽  
Disease States ◽  
Therapeutic Uses ◽  
Potential Biomarker ◽  
Secretion Pathways

Extracellular vesicles (EVs) are membrane-defined nanoparticles released by most cell types. The EVs released by cells may differ quantitatively and qualitatively from physiological states to disease states. There are several unique properties of EVs, including their proteins, lipids and nucleic acid cargoes, stability in circulation, and presence in biofluids, which make them a critical vector for cell-to-cell communication and impart utility as a biomarker. EVs may also serve as a vehicle for selective cargo secretion. Similarly, EV cargo may be selectively manipulated for targeted therapeutic delivery. In this review an overview is provided on the EV classification, biogenesis, and secretion pathways, which are conserved across cell types. Next, cargo characterization and effector cell responses are discussed in the context of nonalcoholic steatohepatitis, alcoholic hepatitis, and acetaminophen-induced liver injury. The review also discusses the potential biomarker and therapeutic uses of circulating EVs.

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