ABSTRACT
Exercise can afford several benefits to combat mood disorders in both rodents and humans. Engagement in various physical activities upregulates levels of neurotrophic factors in several brain regions and improves mental health. However, the type of exercise that regulates mood and the underlying mechanisms in the brain remain elusive. Herein, we performed two distinct types of exercise and RNA sequencing analyses to investigate the effect of exercise on mood-related behaviors and explain the distinct patterns of gene expression. Specifically, resistance exercise exhibited reduced immobility time in the forced swim test when compared with both no exercise and treadmill exercise (in the aerobic training [AT] group). Interestingly, anxiety-like behaviors in the open field and nest-building tests were ameliorated in the AT group when compared with those in the control group; however, this was not observed in the RT group. To elucidate the mechanism underlying these different behavioral changes caused by distinct exercise types, we examined the shift in the gene expression pattern in the hippocampus, a brain region that plays a critical role in regulating mood. We discovered that 38 and 40 genes were altered in the AT and RT groups, respectively, compared with the control group. Both exercises regulated 16 common genes. Compared with the control group, mitogen-activated protein kinase (MAPK) was enriched in the AT group and phosphatidylinositol-3-kinase (PI3K)/AKT and neurotrophin signaling pathways were enriched in the RT group, as determined by bioinformatics pathway analysis. PCR results revealed that Cebpß expression was increased in AT group, and Dcx expression was upregulated in both groups. Our findings indicate that different exercise types may exert substantially distinct effects on mood-like behaviors. Accordingly, appropriate types of exercise can be undertaken based on the mood disorder to be regulated.
Subject(s)
Brain , Depression , Humans , Mice , Animals , Brain/metabolism , Depression/metabolism , Anxiety/metabolism , Swimming , Signal Transduction/physiology , Hippocampus/metabolismABSTRACT
INTRODUCTION: Cytokines of the common γ chain (γc) family are critical for the development, differentiation, and survival of T lineage cells. Cytokines play key roles in immunodeficiencies, autoimmune diseases, allergies, and cancer. Although γc is considered an assistant receptor to transmit cytokine signals and is an indispensable receptor in the immune system, its regulatory mechanism is not yet well understood. OBJECTIVE: This study focused on the molecular mechanisms that γc expression in T cells is regulated under T cell receptor (TCR) stimulation. METHODS: The γc expression in TCR-stimulated T cells was determined by flow cytometry, western blot and quantitative RT-PCR. The regulatory mechanism of γc expression in activated T cells was examined by promoter-luciferase assay and chromatin immunoprecipitation assays. NFAT1 and NFκB deficient cells generated using CRISPR-Cas9 and specific inhibitors were used to examine their role in regulation of γc expression. Specific binding motif was confirmed by γc promotor mutant cells generated using CRISPR-Cas9. IL-7TgγcTg mice were used to examine regulatory role of γc in cytokine signaling. RESULTS: We found that activated T cells significantly upregulated γc expression, wherein NFAT1 and NFκB were key in transcriptional upregulation via T cell receptor stimulation. Also, we identified the functional binding site of the γc promoter and the synergistic effect of NFAT1 and NFκB in the regulation of γc expression. Increased γc expression inhibited IL-7 signaling and rescued lymphoproliferative disorder in an IL-7Tg animal model, providing novel insights into T cell homeostasis. CONCLUSION: Our results indicate functional cooperation between NFAT1 and NFκB in upregulating γc expression in activated T cells. As γc expression also regulates γc cytokine responsiveness, our study suggests that γc expression should be considered as one of the regulators in γc cytokine signaling and the development of T cell immunotherapies. Video Abstract.
Subject(s)
Receptors, Cytokine , T-Lymphocytes , Animals , Mice , Cytokines , Receptors, Antigen, T-Cell , Signal Transduction , HumansABSTRACT
Aminoacyl-tRNA synthetases (ARSs) are emerging as important regulators in various immune diseases; however, their roles in immune cells remain unclear. In this study, using alanyl-tRNA synthetase (AARS) mutant (sti) mice with neurodegenerative disorder, we investigated the effect of translational fidelity in immune cells. Dysfunctional AARS caused disorders in immune cell responses and cellularity. The impairment was caused by dampened TCR signaling than cytokine signaling. Therefore, sti mutant inhibits TCR signaling, impeding T cell survival and responses. B cell numbers were decreased in sti mice. Despite low B cell cellularity, serum IgM, IgA, and IgE levels were higher in sti mice than in wild-type mice. Misacylation of ARS and the consequent translational infidelity induce disturbances in signaling pathways critical for immune cell survival and responses. Our findings provide a novel mechanism by which translational fidelity might play a critical role in cellular and humoral immune responses.
Subject(s)
Amino Acyl-tRNA Synthetases/genetics , B-Lymphocytes/immunology , T-Lymphocytes/immunology , Amino Acyl-tRNA Synthetases/metabolism , Animals , B-Lymphocytes/cytology , B-Lymphocytes/metabolism , Cell Proliferation/drug effects , Cytokines/pharmacology , Female , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Immunoglobulin A/blood , Immunoglobulin E/blood , Immunoglobulin M/blood , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mutagenesis , Receptors, Antigen, T-Cell/metabolism , Signal Transduction/drug effects , T-Lymphocytes/cytology , T-Lymphocytes/metabolismABSTRACT
Hepatic fibrosis is the first stage of liver disease, and can progress to a chronic status, such as cirrhosis or hepatocellular carcinoma. Excessive production of extracellular matrix (ECM) components plays an important role in the development of fibrosis. Mechanistically, transforming growth factor beta (TGFß)-induced phosphorylation of Smad is thought to be a key signaling pathway in the development of liver fibrosis. Although the natural isoquinoline alkaloid oxoglaucine (1,2,9,10-tetramethoxy-7H-dibenzo(de,g)quinolin-7-one) exerts numerous beneficial effects, including anti-cancer, anti-inflammatory, and anti-osteoarthritic effects in diverse cell types, the effects of oxoglaucine on liver fibrosis and fibrogenic gene expression have not been fully elucidated. The aim of this study is to evaluate the signaling pathway and antifibrotic activity of isoquinoline alkaloid oxoglaucine in TFGß-induced hepatic fibrosis in vitro. Using Hepa1c1c7 cells and primary hepatocytes, we demonstrated that oxoglaucine treatment resulted in inhibition of the expression of fibrosis markers such as collagen, fibronectin, and alpha-SMA. Subsequent experiments showed that oxoglaucine suppressed TGFß-induced phosphorylation of Smad2 and reactive oxygen species (ROS) generation, without altering cell proliferation. We further determined that the increase in Smad7 by oxoglaucine treatment is responsible for the inhibition of Smad2 phosphorylation and the anti-fibrogenic effects. These findings indicate that oxoglaucine plays a crucial role in suppression of fibrosis in hepatocytes, thereby making it a potential drug candidate for treatment of liver fibrosis.
Subject(s)
Liver Cirrhosis , Transforming Growth Factor beta , Humans , Transforming Growth Factor beta/metabolism , Phosphorylation , Reactive Oxygen Species/metabolism , Liver Cirrhosis/chemically induced , Liver Cirrhosis/drug therapy , Liver Cirrhosis/metabolism , Fibrosis , Hepatic Stellate Cells , Transforming Growth Factor beta1/metabolism , Smad Proteins/metabolismABSTRACT
Oxidative stress has been demonstrated to play a pivotal role in the pathological processes of many neurodegenerative diseases. In the present study, we demonstrated that Chrysanthemum boreale Makino extract (CBME) suppresses oxidative stress-induced neurotoxicity in human neuroblastoma SH-SY5Y cells and elucidated the underlying molecular mechanism. Our observations revealed that CBME effectively protected neuronal cells against H2O2-induced cell death by preventing caspase-3 activation, Bax upregulation, Bcl-2 downregulation, activation of three mitogen-activated protein kinases (MAPKs), cAMP response element-binding protein (CREB) and NF-κB phosphorylation, and iNOS induction. These results provide evidence that CBME has remarkable neuroprotective properties in SH-SY5Y cells against oxidative damage, suggesting that the complementary or even alternative role of CBME in preventing and treating neurodegenerative diseases is worth further studies.
Subject(s)
Chrysanthemum , Neuroblastoma , Neurodegenerative Diseases , Neuroprotective Agents , Apoptosis , Cell Line, Tumor , Cell Survival , Chrysanthemum/metabolism , Humans , Hydrogen Peroxide/metabolism , Hydrogen Peroxide/pharmacology , Neuroblastoma/pathology , Neuroprotective Agents/pharmacology , Oxidative Stress , Reactive Oxygen Species/metabolismABSTRACT
Scleroderma is an autoimmune disease caused by the abnormal regulation of extracellular matrix synthesis and is activated by non-regulated inflammatory cells and cytokines. Echinochrome A (EchA), a natural pigment isolated from sea urchins, has been demonstrated to have antioxidant activities and beneficial effects in various disease models. The present study demonstrates for the first time that EchA treatment alleviates bleomycin-induced scleroderma by normalizing dermal thickness and suppressing collagen deposition in vivo. EchA treatment reduces the number of activated myofibroblasts expressing α-SMA, vimentin, and phosphorylated Smad3 in bleomycin-induced scleroderma. In addition, it decreased the number of macrophages, including M1 and M2 types in the affected skin, suggesting the induction of an anti-inflammatory effect. Furthermore, EchA treatment markedly attenuated serum levels of inflammatory cytokines, such as tumor necrosis factor-α and interferon-γ, in a murine scleroderma model. Taken together, these results suggest that EchA is highly useful for the treatment of scleroderma, exerting anti-fibrosis and anti-inflammatory effects.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Macrophages/drug effects , Myofibroblasts/drug effects , Naphthoquinones/pharmacology , Scleroderma, Systemic/prevention & control , Skin/drug effects , Actins/metabolism , Animals , Bleomycin , Collagen/metabolism , Cytokines/metabolism , Disease Models, Animal , Fibrosis , Humans , Inflammation Mediators/metabolism , Macrophages/immunology , Macrophages/metabolism , Macrophages/pathology , Male , Mice , Mice, Inbred C57BL , Myofibroblasts/immunology , Myofibroblasts/metabolism , Myofibroblasts/pathology , Phosphorylation , RAW 264.7 Cells , Scleroderma, Systemic/chemically induced , Scleroderma, Systemic/immunology , Scleroderma, Systemic/metabolism , Skin/immunology , Skin/metabolism , Skin/pathology , Smad3 Protein/metabolism , Vimentin/metabolismABSTRACT
Anterior gradient protein 2 homolog (AGR2) belongs to the disulfide isomerase family of endoplasmic reticulum proteins. Itis overexpressed in several types of solid tumors, including tumors of the prostate, lung, and pancreas. However, the role of AGR2 in breast cancer and the regulatory mechanisms underlying AGR2 protein expressionare not fullyunderstood. We demonstrated that AGR2 levels are increased under hypoxic conditions and in breast cancer tumors. Mechanistically, Twist1 binds to, and activates the AGR2 promoter via an E-box sequence. Under hypoxic conditions, the increased expression of ARG2 is attenuated when Twist1 levels are reduced by shRNA. Conversely, Twist1 overexpression fully reverses decreased AGR2 levels upon HIF-1α knockdown. Notably, AGR2 is required for Twist1-induced proliferation, migration, and invasion of breast cancer cells. Collectively, these findings extend our understanding of AGR2 regulation in breast cancer and may contribute to development of Twist1-AGR2 targeting therapeutics for breast cancer.
Subject(s)
Breast Neoplasms/genetics , Gene Expression Regulation, Neoplastic , Mucoproteins/genetics , Nuclear Proteins/genetics , Oncogene Proteins/genetics , Twist-Related Protein 1/genetics , Breast Neoplasms/pathology , Cell Line, Tumor , Cell Movement , Cell Proliferation , Female , Humans , Middle Aged , Promoter Regions, GeneticABSTRACT
Excessive alcohol consumption is a major public health problem worldwide. Although drinking habits are known to be inherited, few genes have been identified that are robustly linked to alcohol drinking. We conducted a genome-wide association metaanalysis and replication study among >105,000 individuals of European ancestry and identified ß-Klotho (KLB) as a locus associated with alcohol consumption (rs11940694; P = 9.2 × 10-12). ß-Klotho is an obligate coreceptor for the hormone FGF21, which is secreted from the liver and implicated in macronutrient preference in humans. We show that brain-specific ß-Klotho KO mice have an increased alcohol preference and that FGF21 inhibits alcohol drinking by acting on the brain. These data suggest that a liver-brain endocrine axis may play an important role in the regulation of alcohol drinking behavior and provide a unique pharmacologic target for reducing alcohol consumption.
Subject(s)
Alcohol Drinking/genetics , Alcohol Drinking/physiopathology , Fibroblast Growth Factors/physiology , Membrane Proteins/genetics , Animals , Behavior, Animal/physiology , Brain/physiopathology , Emotions/physiology , Female , Genome-Wide Association Study , Humans , Klotho Proteins , Liver/physiopathology , Male , Membrane Proteins/deficiency , Membrane Proteins/physiology , Mice , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Knockout , Polymorphism, Single NucleotideABSTRACT
Secretory proteins play important roles in the cross-talk of individual functional units, including cells. Since secretory proteins are essential for signal transduction, they are closely related with disease development, including metabolic and neural diseases. In metabolic diseases, adipokines, myokines, and hepatokines are secreted from respective organs under specific environmental conditions, and play roles in glucose homeostasis, angiogenesis, and inflammation. In neural diseases, astrocytes and microglia cells secrete cytokines and chemokines that play roles in neurotoxic and neuroprotective responses. Mass spectrometry-based secretome profiling is a powerful strategy to identify and characterize secretory proteins. This strategy involves stepwise processes such as the collection of conditioned medium (CM) containing secretome proteins and concentration of the CM, peptide preparation, mass analysis, database search, and filtering of secretory proteins; each step requires certain conditions to obtain reliable results. Proteomic analysis of extracellular vesicles has become a new research focus for understanding the additional extracellular functions of intracellular proteins. Here, we provide a review of the insights obtained from secretome analyses with regard to disease mechanisms, and highlight the future prospects of this technology. Continued research in this field is expected to provide valuable information on cell-to-cell communication and uncover new pathological mechanisms.
Subject(s)
Extracellular Vesicles/metabolism , Proteins/metabolism , Proteomics/methods , Animals , Chromatography, Liquid/methods , Extracellular Vesicles/chemistry , Humans , Metabolic Diseases/metabolism , Nervous System Diseases/metabolism , Proteins/analysis , Tandem Mass Spectrometry/methods , Vascular Diseases/metabolismABSTRACT
Elevated levels of the free fatty acid palmitate are found in the plasma of obese patients and induce insulin resistance. Skeletal muscle secretes myokines as extracellular signaling mediators in response to pathophysiological conditions. Here, we identified and characterized the skeletal muscle secretome in response to palmitate-induced insulin resistance. Using a quantitative proteomic approach, we identified 36 secretory proteins modulated by palmitate-induced insulin resistance. Bioinformatics analysis revealed that palmitate-induced insulin resistance induced cellular stress and modulated secretory events. We found that the decrease in the level of annexin A1, a secretory protein, depended on palmitate, and that annexin A1 and its receptor, formyl peptide receptor 2 agonist, played a protective role in the palmitate-induced insulin resistance of L6 myotubes through PKC-θ modulation. In mice fed with a high-fat diet, treatment with the formyl peptide receptor 2 agonist improved systemic insulin sensitivity. Thus, we identified myokine candidates modulated by palmitate-induced insulin resistance and found that the annexin A1- formyl peptide receptor 2 pathway mediated the insulin resistance of skeletal muscle, as well as systemic insulin sensitivity.
Subject(s)
Annexin A1/metabolism , Insulin Resistance , Muscle Fibers, Skeletal/metabolism , Palmitates/pharmacology , Proteomics/methods , Receptors, Formyl Peptide/agonists , Animals , Annexin A1/agonists , Cell Line , Computational Biology , Culture Media, Conditioned/pharmacology , Diet, High-Fat , Insulin/pharmacology , Male , Mice, Inbred C57BL , Muscle Fibers, Skeletal/drug effects , Oligopeptides/pharmacology , Rats , Receptors, Formyl Peptide/metabolismABSTRACT
OBJECTIVE: Aberrant regulation of the proliferation, survival, and migration of endothelial cells (ECs) is closely related to the abnormal angiogenesis that occurs in hypoxia-induced pathological situations, such as cancer and vascular retinopathy. Hypoxic conditions and the subsequent upregulation of hypoxia-inducible factor-1α and target genes are important for the angiogenic functions of ECs. Phospholipase D2 (PLD2) is a crucial signaling mediator that stimulates the production of the second messenger phosphatidic acid. PLD2 is involved in various cellular functions; however, its specific roles in ECs under hypoxia and in vivo angiogenesis remain unclear. In the present study, we investigated the potential roles of PLD2 in ECs under hypoxia and in hypoxia-induced pathological angiogenesis in vivo. APPROACH AND RESULTS: Pld2 knockout ECs exhibited decreased hypoxia-induced cellular responses in survival, migration, and thus vessel sprouting. Analysis of hypoxia-induced gene expression revealed that PLD2 deficiency disrupted the upregulation of hypoxia-inducible factor-1α target genes, including VEGF, PFKFB3, HMOX-1, and NTRK2. Consistent with this, PLD2 contributed to hypoxia-induced hypoxia-inducible factor-1α expression at the translational level. The roles of PLD2 in hypoxia-induced in vivo pathological angiogenesis were assessed using oxygen-induced retinopathy and tumor implantation models in endothelial-specific Pld2 knockout mice. Pld2 endothelial-specific knockout retinae showed decreased neovascular tuft formation, despite a larger avascular region. Tumor growth and tumor blood vessel formation were also reduced in Pld2 endothelial-specific knockout mice. CONCLUSIONS: Our findings demonstrate a novel role for endothelial PLD2 in the survival and migration of ECs under hypoxia via the expression of hypoxia-inducible factor-1α and in pathological retinal angiogenesis and tumor angiogenesis in vivo.
Subject(s)
Carcinoma, Lewis Lung/blood supply , Endothelial Cells/enzymology , Hypoxia/complications , Neovascularization, Pathologic , Phospholipase D/deficiency , Retinal Neovascularization/enzymology , Retinal Vessels/enzymology , Animals , Animals, Newborn , Cell Hypoxia , Cell Movement , Cell Proliferation , Cell Survival , Cells, Cultured , Disease Models, Animal , Endothelial Cells/pathology , Gene Expression Regulation , Human Umbilical Vein Endothelial Cells/enzymology , Human Umbilical Vein Endothelial Cells/pathology , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Phospholipase D/genetics , RNA Interference , Retinal Neovascularization/etiology , Retinal Neovascularization/genetics , Retinal Neovascularization/pathology , Retinal Vessels/pathology , Time Factors , Tissue Culture Techniques , TransfectionABSTRACT
Voluntary exercise is known to have an antidepressant effect. However, the underlying mechanism for this antidepressant action of exercise remains unclear, and little progress has been made in identifying genes that are directly involved. We have identified macrophage migration inhibitory factor (MIF) by analyzing existing mRNA microarray data and confirmed the augmented expression of selected genes under two experimental conditions: voluntary exercise and electroconvulsive seizure. A proinflammatory cytokine, MIF is expressed in the central nervous system and involved in innate and adaptive immune responses. A recent study reported that MIF is involved in antidepressant-induced hippocampal neurogenesis, but the mechanism remains elusive. In our data, tryptophan hydroxylase 2 (Tph2) and brain-derived neurotrophic factor (Bdnf) expression were induced after MIF treatment in vitro, as well as during both exercise and electroconvulsive seizure in vivo. This increment of Tph2 was accompanied by increases in the levels of total serotonin in vitro. Moreover, the MIF receptor CD74 and the ERK1/2 pathway mediate the MIF-induced Tph2 and Bdnf gene expression as well as serotonin content. Experiments in Mif(-/-) mice revealed depression-like behaviors and a blunted antidepressant effect of exercise, as reflected by changes in Tph2 and Bdnf expression in the forced swim test. In addition, administration of recombinant MIF protein produced antidepressant-like behavior in rats in the forced swim test. Taken together, these results suggest a role of MIF in mediating the antidepressant action of exercise, probably by enhancing serotonin neurotransmission and neurotrophic factor-induced neurogenesis in the brain.
Subject(s)
Depression/therapy , Electroshock/methods , Intramolecular Oxidoreductases/pharmacology , Macrophage Migration-Inhibitory Factors/pharmacology , Motor Activity/physiology , Analysis of Variance , Animals , Blotting, Western , Brain-Derived Neurotrophic Factor/metabolism , Cells, Cultured , DNA Primers/genetics , Immunohistochemistry , Infusions, Intraventricular , Intramolecular Oxidoreductases/administration & dosage , Intramolecular Oxidoreductases/genetics , Macrophage Migration-Inhibitory Factors/administration & dosage , Macrophage Migration-Inhibitory Factors/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Motor Activity/drug effects , Rats , Rats, Sprague-Dawley , Real-Time Polymerase Chain Reaction , Recombinant Proteins/pharmacology , Reverse Transcriptase Polymerase Chain Reaction , Serotonin/metabolism , Tryptophan Hydroxylase/metabolismABSTRACT
AIMS/HYPOTHESIS: Obesity-induced inflammation is initiated by the recruitment of macrophages into adipose tissue. The recruited macrophages, called adipose tissue macrophages, secrete several proinflammatory cytokines that cause low-grade systemic inflammation and insulin resistance. The aim of this study was to find macrophage-recruiting factors that are thought to provide a crucial connection between obesity and insulin resistance. METHODS: We used chemotaxis assay, reverse phase HPLC and tandem MS analysis to find chemotactic factors from adipocytes. The expression of chemokines and macrophage markers was evaluated by quantitative RT-PCR, immunohistochemistry and FACS analysis. RESULTS: We report our finding that the chemokine (C-X-C motif) ligand 12 (CXCL12, also known as stromal cell-derived factor 1), identified from 3T3-L1 adipocyte conditioned medium, induces monocyte migration via its receptor chemokine (C-X-C motif) receptor 4 (CXCR4). Diet-induced obese mice demonstrated a robust increase of CXCL12 expression in white adipose tissue (WAT). Treatment of obese mice with a CXCR4 antagonist reduced macrophage accumulation and production of proinflammatory cytokines in WAT, and improved systemic insulin sensitivity. CONCLUSIONS/INTERPRETATION: In this study we found that CXCL12 is an adipocyte-derived chemotactic factor that recruits macrophages, and that it is a required factor for the establishment of obesity-induced adipose tissue inflammation and systemic insulin resistance.
Subject(s)
Adipose Tissue/metabolism , Chemokine CXCL12/metabolism , Insulin Resistance/physiology , Macrophages/metabolism , 3T3-L1 Cells , Adipocytes/metabolism , Animals , Cell Line , Chemotaxis/physiology , Mice , Obesity/metabolismABSTRACT
AMP-activated protein kinase has been described as a key signaling protein that can regulate energy homeostasis. Here, we aimed to characterize novel AMP-activated kinase (AMPK)-activating compounds that have a much lower effective concentration than metformin. As a result, emodin, a natural anthraquinone derivative, was shown to stimulate AMPK activity in skeletal muscle and liver cells. Emodin enhanced GLUT4 translocation and [(14)C]glucose uptake into the myotube in an AMPK-dependent manner. Also, emodin inhibited glucose production by suppressing the expression of key gluconeogenic genes, such as phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, in hepatocytes. Furthermore, we found that emodin can activate AMPK by inhibiting mitochondrial respiratory complex I activity, leading to increased reactive oxygen species and Ca(2+)/calmodulin-dependent protein kinase kinase activity. Finally, we confirmed that a single dose administration of emodin significantly decreased the fasting plasma glucose levels and improved glucose tolerance in C57Bl/6J mice. Increased insulin sensitivity was also confirmed after daily injection of emodin for 8 days using an insulin tolerance test and insulin-stimulated PI3K phosphorylation in wild type and high fat diet-induced diabetic mouse models. Our study suggests that emodin regulates glucose homeostasis in vivo by AMPK activation and that this may represent a novel therapeutic principle in the treatment of type 2 diabetic models.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Diabetes Mellitus, Type 2/drug therapy , Emodin/pharmacology , Gene Expression Regulation , Glucose/metabolism , Animals , Blood Glucose/metabolism , Calcium/metabolism , Cell Line , Enzyme Activation , Glucose Tolerance Test , Insulin Resistance , Liver/metabolism , Male , Mice , Models, Genetic , Muscle, Skeletal/cytology , Myoblasts/cytologyABSTRACT
The liver is vulnerable to various hepatotoxins, including carbon tetrachloride (CCl4), which induces oxidative stress and apoptosis by producing reactive oxygen species (ROS) and activating the mitogen-activated protein kinase (MAPK) pathway. Cereblon (CRBN), a multifunctional protein implicated in various cellular processes, functions in the pathogenesis of various diseases; however, its function in liver injury remains unknown. We established a CRBN-knockout (KO) HepG2 cell line and examined its effect on CCl4-induced hepatocellular damage. CRBN-KO cells exhibited reduced sensitivity to CCl4-induced cytotoxicity, as evidenced by decreased levels of apoptosis markers, such as cleaved caspase-3, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. CRBN deficiency enhanced antioxidant defense, with increased superoxide dismutase activity and glutathione ratios (GSH/GSSG), as well as reduced pro-inflammatory cytokine expression. Mechanistically, the protective effects of CRBN deficiency appeared to involve the attenuation of the MAPK-mediated pathways, particularly through decreased phosphorylation of JNK and ERK. Overall, these results suggest the crucial role of CRBN in mediating the hepatocellular response to oxidative stress and inflammation triggered by CCl4 exposure, offering potential clinical implications for liver injury in a wide range of liver diseases.
Subject(s)
Adaptor Proteins, Signal Transducing , Apoptosis , Carbon Tetrachloride , Chemical and Drug Induced Liver Injury , Oxidative Stress , Humans , Apoptosis/drug effects , Hep G2 Cells , Carbon Tetrachloride/toxicity , Chemical and Drug Induced Liver Injury/metabolism , Chemical and Drug Induced Liver Injury/etiology , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Signal Transducing/genetics , Oxidative Stress/drug effects , Ubiquitin-Protein Ligases/metabolism , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/deficiency , MAP Kinase Signaling System/drug effects , Mitogen-Activated Protein Kinases/metabolism , Reactive Oxygen Species/metabolismABSTRACT
Oxysterols are oxygenated cholesterol derivatives and important regulators of cholesterol metabolism, lipid homeostasis, the immune system, and membrane fluidity regulation. Although the detailed mechanism of action of oxysterols remains unclear, activation of some nuclear receptors, such as liver X receptor α (LXRα) and RAR-related orphan receptors, have been believed to be critical for the regulation of various physiological processes in multiple tissues. 27-Hydroxycholesterol (27-OHC) is an endogenous oxysterol, which has an intermediate function in cholesterol catabolism to bile acid synthesis. According to previous studies, however, there are opposing opinions on whether 27-OHC activates human LXR. Recently, several studies have shown that 27-OHC can activate or inhibit the function of estrogen receptors ERα and ERß in a tissue-specific manner, indicating that the understanding of 27-OHC-mediated biological output is very complicated. This review summarizes the pathophysiological relevance of 27-OHC in various tissues, with a special discussion on their functions in human diseases.
Subject(s)
Hydroxycholesterols , Orphan Nuclear Receptors , Humans , Hydroxycholesterols/metabolism , Hydroxycholesterols/pharmacology , Orphan Nuclear Receptors/metabolism , Receptors, Estrogen/metabolismABSTRACT
Oxysterols are oxygenated derivatives of cholesterol that contain an additional hydroxy, epoxide, or ketone group in the sterol nucleus and/or a hydroxyl group in the side chain of the cholesterol molecule. 27-Hydroxycholesterol (27HC) is a side-chain oxysterol that is oxygenated at the 27th carbon atom of cholesterol. The oxysterol (27HC) is produced via oxidation by sterol 27-hydroxylase (CYP27A1) and metabolized via oxysterol 7a-hydroxylase (CYP7B1) for bile acid synthesis in the liver. A previous study has demonstrated that treatment with the alternative Estrogen receptor alpha (ERα) ligand 27HC induces ERα-dependent hematopoietic stem cell (HSC) mobilization. In addition, Cyp27a1-deficient mice demonstrate significantly reduced 27HC levels and HSC mobilization. Here, we report that exogenous 27HC treatment leads to a substantial reduction in the hematopoietic stem and progenitor cell (HSPC) population owing to significantly increased reactive oxygen species (ROS) levels and apoptosis in the bone marrow (BM). However, 27HC does not influence the population of mature hematopoietic cells in the BM. Furthermore, exogenous 27HC treatment suppresses cell growth and promotes ROS production and apoptosis in leukemic cells. Moreover, acute myeloid leukemia (AML) patients with high CYP7B1 expression (expected to have inhibition of 27HC) had significantly shorter survival than those with low CYP7B1 expression (expected to have an elevation of 27HC). Single-cell RNA-sequencing (scRNA seq) analysis revealed that the expression of CYP7B1 was significantly increased in AML patients. Thus, our study suggests that 27HC may serve as a potent agent for regulating pools of HSPCs and may have an application as a novel therapeutic target for hematological malignancies. Collectively, pharmacological inhibition of CYP7B1 (expected to have an elevation of 27HC) would potentially have fewer long-term hematological side effects, particularly when used in combination with chemotherapy or radiation for the treatment of leukemia patients.
Subject(s)
Estrogen Receptor alpha , Oxysterols , Mice , Animals , Reactive Oxygen Species , Estrogen Receptor alpha/metabolism , Hydroxycholesterols/pharmacology , Hydroxycholesterols/metabolism , Hematopoietic Stem Cells/metabolism , Cholesterol , Myeloid Cells/metabolism , ApoptosisABSTRACT
There is a strong possibility that skeletal muscle can respond to irregular metabolic states by secreting specific cytokines. Obesity-related chronic inflammation, mediated by pro-inflammatory cytokines, is believed to be one of the causes of insulin resistance that results in type 2 diabetes. Here, we attempted to identify and characterize the members of the skeletal muscle secretome in response to tumor necrosis factor-alpha (TNF-α)-induced insulin resistance. To conduct this study, we comparatively analyzed the media levels of proteins released from L6 skeletal muscle cells. We found 28 TNF-α modulated secretory proteins by using separate filtering methods: Gene Ontology, SignalP, and SecretomeP, as well as the normalized Spectral Index for label-free quantification. Ten of these secretory proteins were increased and 18 secretory proteins were decreased by TNF-α treatment. Using microarray analysis of Zuker diabetic rat skeletal muscle combined with bioinformatics and Q-PCR, we found a correlation between TNF-α-mediated insulin resistance and type 2 diabetes. This novel approach combining analysis of the conditioned secretome and transcriptome has identified several previously unknown, TNF-α-dependent secretory proteins, which establish a foothold for research on the different causes of insulin resistance and their relationships with each other.
Subject(s)
Cytokines/metabolism , Muscle Fibers, Skeletal/drug effects , Muscle Proteins/metabolism , Muscle, Skeletal/metabolism , Proteomics/methods , Tumor Necrosis Factor-alpha/pharmacology , Animals , Blotting, Western , Cells, Cultured , Computational Biology , Culture Media, Conditioned , Cytokines/analysis , Databases, Protein , Diabetes Mellitus, Type 2/metabolism , Gene Expression Profiling/methods , Glucose Transporter Type 4/metabolism , Insulin/pharmacology , Insulin Resistance , Male , Mass Spectrometry/methods , Muscle Fibers, Skeletal/metabolism , Muscle Fibers, Skeletal/pathology , Muscle Proteins/analysis , Muscle, Skeletal/drug effects , Muscle, Skeletal/pathology , Rats , Real-Time Polymerase Chain Reaction , TranscriptomeABSTRACT
Brown adipose tissue (BAT) plays an important role in thermogenic regulation, which contributes to alleviating diet-induced obesity through uncoupling protein 1 (UCP1) expression. While cold exposure and physical exercise are known to increase BAT development and UCP1 expression, the contribution of hyperbaric oxygen (HBO) therapy to BAT maturation remains largely unknown. Here, we show that HBO treatment sufficiently increases BAT volumes and thermogenic protein levels in Sprague-Dawley rats. Through 18F-FDG PET/CT analysis, we found that exposure to high-pressure oxygen (1.5-2.5 ATA) for 7 consecutive days increased radiolabeled glucose uptake and BAT development to an extent comparable to cold exposure. Consistent with BAT maturation, thermogenic protein levels, such as those of UCP1 and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), were largely increased by HBO treatment. Taken together, we suggest HBO therapy as a novel method of inducing BAT development, considering its therapeutic potential for the treatment of metabolic disorders.
Subject(s)
Adipose Tissue, Brown , Hyperbaric Oxygenation , Animals , Cold Temperature , Positron Emission Tomography Computed Tomography , Rats , Rats, Sprague-Dawley , Uncoupling Protein 1/geneticsABSTRACT
Proteomics has become an important field in molecular sciences, as it provides valuable information on the identity, expression levels, and modification of proteins. For example, cancer proteomics unraveled key information in mechanistic studies on tumor growth and metastasis, which has contributed to the identification of clinically applicable biomarkers as well as therapeutic targets. Several cancer proteome databases have been established and are being shared worldwide. Importantly, the integration of proteomics studies with other omics is providing extensive data related to molecular mechanisms and target modulators. These data may be analyzed and processed through bioinformatic pipelines to obtain useful information. The purpose of this review is to provide an overview of cancer proteomics and recent advances in proteomic techniques. In particular, we aim to offer insights into current proteomics studies of brain cancer, in which proteomic applications are in a relatively early stage. This review covers applications of proteomics from the discovery of biomarkers to the characterization of molecular mechanisms through advances in technology. Moreover, it addresses global trends in proteomics approaches for translational research. As a core method in translational research, the continued development of this field is expected to provide valuable information at a scale beyond that previously seen.