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Acta Pharmacologica Sinica Oct 2022Obesity is an important independent risk factor for cardiovascular diseases, remaining an important health concern worldwide. Evidence shows that saturated fatty...
Obesity is an important independent risk factor for cardiovascular diseases, remaining an important health concern worldwide. Evidence shows that saturated fatty acid-induced inflammation in cardiomyocytes contributes to obesity-related cardiomyopathy. Dapagliflozin (Dapa), a selective SGLT2 inhibitor, exerts a favorable preventive activity in heart failure. In this study, we investigated the protective effect of Dapa against cardiomyopathy caused by high fat diet-induced obesity in vitro and in vivo. Cultured rat cardiomyocyte H9c2 cells were pretreated with Dapa (1, 2.5 μM) for 1.5 h, followed by treatment with palmitic acid (PA, 200 μM) for 24 h. We showed that Dapa pretreatment concentration-dependently attenuated PA-induced cell hypertrophy, fibrosis and apoptosis. Transcriptome analysis revealed that inhibition of PA-activated MAPK/AP-1 pathway contributed to the protective effect of Dapa in H9c2 cells, and this was confirmed by anti-p-cJUN fluorescence staining assay. Using surface plasmon resonance analysis we found the direct binding of Dapa with NHE1. Gain and loss of function experiments further demonstrated the role of NHE1 in the protection of Dapa. In vivo experiments were conducted in mice fed a high fat diet for 5 months. The mice were administered Dapa (1 mg·kg·d, i.g.) in the last 2 months. Dapa administration significantly reduced the body weight and improved the serum lipid profiles. Dapa administration also alleviated HFD-induced cardiac dysfunction and cardiac aberrant remodeling via inhibiting MAPK/AP-1 pathway and ameliorating cardiac inflammation. In conclusion, Dapa exerts a direct protective effect against saturated fatty acid-induced cardiomyocyte injury in addition to the lowering effect on serum lipids. The protective effect results from negative regulating MAPK/AP-1 pathway in a NHE1-dependent way. The current study highlights the potential of clinical use of Dapa in the prevention of obesity-related cardiac dysfunction.
Topics: Animals; Benzhydryl Compounds; Cardiomyopathies; Glucosides; Inflammation; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; Obesity; Palmitic Acid; Rats; Sodium-Glucose Transporter 2 Inhibitors; Transcription Factor AP-1
PubMed: 35217813
DOI: 10.1038/s41401-022-00885-8 -
Oxidative Medicine and Cellular... 2022Diabetes mellitus (DM) can induce cardiomyocyte injury and lead to diabetic cardiomyopathy (DCM) which presently has no specific treatments and consequently increase...
BACKGROUND
Diabetes mellitus (DM) can induce cardiomyocyte injury and lead to diabetic cardiomyopathy (DCM) which presently has no specific treatments and consequently increase risk of mortality.
OBJECTIVE
To characterize the therapeutic effect of 6-gingerol (6-G) on DCM and identify its potential mechanism.
METHODS
In vivo streptozotocin- (STZ-) induced DM model was established by using a high-fat diet and STZ, followed by low-dose (25 mg/kg) and high-dose (75 mg/kg) 6-G intervention. For an in vitro DCM model, H9c2 rat cardiomyoblast cells were stimulated with high glucose (glucose = 33 mM) and palmitic acid (100 M) and then treated with 6-G (100 M). Histological and echocardiographic analyses were used to assess the effect of 6-G on cardiac structure and function in DCM. Western blotting, ELISA, and real-time qPCR were used to assess the expression of ferroptosis, inflammation, and the Nrf2/HO-1 pathway-related proteins and RNAs. Protein expression of collagen I and collagen III was assessed by immunohistochemistry, and kits were used to assay SOD, MDA, and iron levels.
RESULTS
The results showed that 6-G decreased cardiac injury in both mouse and cell models of DCM. The cardiomyocyte hypertrophy and interstitial fibrosis were attenuated by 6-G treatment in vivo and resulted in an improved heart function. 6-G inhibited the expression of ferroptosis-related protein FACL4 and the content of iron and enhanced the expression of anti-ferroptosis-related protein GPX4. In addition, 6-G also diminished the secretion of inflammatory cytokines, including IL-1, IL-6, and TNF-. 6-G treatment activated the Nrf2/HO-1 pathway, enhanced antioxidative stress capacity proved by increased activity of SOD, and decreased MDA production. Compared with in vivo, 6-G treatment of H9c2 cells treated with high glucose and palmitic acid could produce a similar effect.
CONCLUSION
These findings suggest that 6-G could protect against DCM by the mechanism of ferroptosis inhibition and inflammation reduction via enhancing the Nrf2/HO-1 pathway.
Topics: Rats; Mice; Animals; Diabetic Cardiomyopathies; NF-E2-Related Factor 2; Palmitic Acid; Oxidative Stress; Inflammation; Glucose; Superoxide Dismutase; Diabetes Mellitus
PubMed: 36624878
DOI: 10.1155/2022/3027514 -
Cell Metabolism Mar 2021The health effect of dietary fat has been one of the most vexing issues in the field of nutrition. Few animal studies have examined the impact of high-fat diets on...
The health effect of dietary fat has been one of the most vexing issues in the field of nutrition. Few animal studies have examined the impact of high-fat diets on lifespan by controlling energy intake. In this study, we found that compared to a normal diet, an isocaloric moderately high-fat diet (IHF) significantly prolonged lifespan by decreasing the profiles of free fatty acids (FFAs) in serum and multiple tissues via downregulating FFA anabolism and upregulating catabolism pathways in rats and flies. Proteomics analysis in rats identified PPRC1 as a key protein that was significantly upregulated by nearly 2-fold by IHF, and among the FFAs, only palmitic acid (PA) was robustly and negatively associated with the expression of PPRC1. Using PPRC1 transgenic RNAi/overexpression flies and in vitro experiments, we demonstrated that IHF significantly reduced PA, which could upregulate PPRC1 through PPARG, resulting in improvements in oxidative stress and inflammation and prolonging the lifespan.
Topics: 3-Hydroxybutyric Acid; Animals; Dietary Fats; Drosophila; Drosophila Proteins; Fatty Acids, Nonesterified; Liver; Longevity; Male; Obesity; Oxidative Stress; PPAR gamma; Palmitic Acid; RNA Interference; RNA, Small Interfering; Rats; Rats, Wistar; Transcription Factors; Up-Regulation
PubMed: 33440166
DOI: 10.1016/j.cmet.2020.12.017 -
Journal of Cellular and Molecular... May 2020Non-alcohol fatty liver disease (NAFLD) is a common disease which causes serious liver damage. Geniposide (GEN), a kind of iridoid glycoside extracted from Gardenia...
Non-alcohol fatty liver disease (NAFLD) is a common disease which causes serious liver damage. Geniposide (GEN), a kind of iridoid glycoside extracted from Gardenia jasminoides fruit, has many biological effects, such as resistance to cell damage and anti-neurodegenerative disorder. Lipid accumulation was obvious in tyloxapol-induced liver and oil acid (OA) with palmitic acid (PA)-induced HepG2 cells compared with the control groups while GEN improved the increasing conditions. GEN significantly lessened the total cholesterol (TC), the triglyceride (TG), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), myeloperoxidase (MPO), reactive oxygen species (ROS) and increased high-density lipoprotein (HDL), superoxide dismutase (SOD) to response the oxidative stress via activating nuclear factor erythroid-2-related factor 2 (Nrf2), haeme oxygenase (HO)-1 and peroxisome proliferator-activated receptor (PPAR)α which may influence the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) signalling pathway in mice and cells. Additionally, GEN evidently decreased the contents of sterol regulatory element-binding proteins (SREBP)-1c, phosphorylation (P)-mechanistic target of rapamycin complex (mTORC), P-S6K, P-S6 and high mobility group protein (HMGB) 1 via inhibiting the expression of phosphoinositide 3-kinase (PI3K), and these were totally abrogated in Nrf2 mice. Our study firstly proved the protective effect of GEN on lipid accumulation via enhancing the ability of antioxidative stress and anti-inflammation which were mostly depend on up-regulating the protein expression of Nrf2/HO-1 and AMPK signalling pathways, thereby suppressed the phosphorylation of mTORC and its related protein.
Topics: AMP-Activated Protein Kinases; Animals; Gene Expression Regulation; Hep G2 Cells; Humans; Inflammation; Iridoids; Lipids; Male; Mice; Mice, Inbred C57BL; NF-E2-Related Factor 2; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Palmitic Acid; Phosphatidylinositol 3-Kinases; Phosphorylation; Polyethylene Glycols; Signal Transduction; TOR Serine-Threonine Kinases
PubMed: 32293113
DOI: 10.1111/jcmm.15139 -
Cells Nov 2021Non-alcoholic fatty liver disease (NAFLD) is a global clinical problem. The MD2-TLR4 pathway exacerbates NAFLD progression by promoting inflammation. Long-term exercise...
Non-alcoholic fatty liver disease (NAFLD) is a global clinical problem. The MD2-TLR4 pathway exacerbates NAFLD progression by promoting inflammation. Long-term exercise is considered to improve NAFLD but the underlying mechanism is still unclear. In this study, we examined the protective effect and molecular mechanism of exercise on high-fat diet (HFD)-induced liver injury. In an HFD-induced NAFLD mouse model, exercise training significantly decreased hepatic steatosis and fibrosis. Interestingly, exercise training blocked the binding of MD2-TLR4 and decreased the downstream inflammatory response. Irisin is a myokine that is highly expressed in response to exercise and exerts anti-inflammatory effects. We found that circulating irisin levels and muscle irisin expression were significantly increased in exercised mice, suggesting that irisin could mediate the effect of exercise on NAFLD. In vitro studies showed that irisin improved lipid metabolism, fibrosis, and inflammation in palmitic acid (PA)-stimulated AML12 cells. Moreover, binding assay results showed that irisin disturbed MD2-TLR4 complex formation by directly binding with MD2 but not TLR4, and interfered with the recognition of stimuli such as PA and lipopolysaccharide with MD2. Our study provides novel evidence that exercise-induced irisin inhibits inflammation via competitive binding with MD2 to improve NAFLD. Thus, irisin could be considered a potential therapy for NAFLD.
Topics: Animals; Binding, Competitive; Blood Circulation; Diet, High-Fat; Fibronectins; Hepatocytes; Inflammation; Lipid Metabolism; Liver; Lymphocyte Antigen 96; MAP Kinase Signaling System; Male; Mice, Inbred C57BL; Muscle, Skeletal; NF-kappa B; Non-alcoholic Fatty Liver Disease; Palmitic Acid; Physical Conditioning, Animal; Protein Binding; Toll-Like Receptor 4; Mice
PubMed: 34943814
DOI: 10.3390/cells10123306 -
Autophagy Jan 2022Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease globally. NAFLD is a consequence of fat accumulation in the liver leading to...
Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease globally. NAFLD is a consequence of fat accumulation in the liver leading to lipotoxicity. Increasing evidence has demonstrated the critical role of autophagy in NAFLD. This study uncovers the unexpected role of immune surveillance protein DDX58/Rig-1 (DExD/H box helicase 58) in activating macroautophagy/autophagy and protecting from lipotoxicity associated with NAFLD. Here we show for the first time that DDX58 protein is significantly reduced in nonalcoholic steatohepatitis (NASH) mouse model, an aggressive form of NAFLD characterized by inflammation and fibrosis of the liver. In addition to decreased expression of DDX58, we found that DDX58 activity can be attenuated by treatments with palmitic acid (PA), a saturated fatty acid. To investigate whether PA inhibition of DDX58 is harmful to the cell, we characterized DDX58 function in hepatocytes when exposed to high doses of PA in the presence and/or absence of DDX58. We show that siRNA knockdown of DDX58 promotes apoptosis. Importantly, we show that stable overexpression of DDX58 is protective against toxic levels of PA and stimulates autophagy. This study begins to demonstrate the regulation of the autophagy receptor protein SQSTM1/p62 through DDX58. DDX58 expression directly influences mRNA and protein levels. This work proposes a model in which activating DDX58 increases an autophagic response and this aids in clearing toxic lipid inclusion bodies, which leads to inflammation and apoptosis. Activating a DDX58-induced autophagy response may be a strategy for treating NAFLD.5'pppdsRNA: 5' triphosphate double-stranded RNA; CDAHFD: choline-deficient, L-amino acid defined high-fat diet; CEBPB: CCAAT/enhancer binding protein (C/EBP), beta; CQ: chloroquine; DDX58/retinoic acid inducible gene 1/Rig-1: DExD/H box helicase 58; h: hours; IFIH1/MDA5: interferon induced with helicase C domain 1; IFNB/IFN-β: interferon beta 1, fibroblast; KO: knockout; MAVS: mitochondrial antiviral signaling protein; NAFLD: nonalcoholic fatty liver disease; NASH: nonalcoholic steatohepatitis; NFKB/NF-κB: nuclear factor of kappa light polypeptide gene enhancer in B cells; PA: palmitic acid; poly:IC: polyinosinic:polycytidylic acid; PRR: pattern recognition receptors; PSR: picrosirus red; RAP: rapamycin; RLR: RIG-I-like receptor; SQSTM1/p62: sequestosome 1; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK-binding kinase 1.
Topics: Animals; Autophagy; Cell Death; Inflammation; Mice; Non-alcoholic Fatty Liver Disease; Palmitic Acid; Sequestosome-1 Protein
PubMed: 33966599
DOI: 10.1080/15548627.2021.1920818 -
Biochemical Pharmacology Sep 2023Post-translational modifications are an important mechanism in the regulation of protein expression, function, and degradation. Well-known post-translational... (Review)
Review
Post-translational modifications are an important mechanism in the regulation of protein expression, function, and degradation. Well-known post-translational modifications are phosphorylation, glycosylation, and ubiquitination. However, lipid modifications, including myristoylation, prenylation, and palmitoylation, are poorly studied. Since the early 2000s, researchers have become more interested in lipid modifications, especially palmitoylation. The number of articles in PubMed increased from about 350 between 2000 and 2005 to more than 600 annually during the past ten years. S-palmitoylation, where the 16-carbon saturated (C16:0) palmitic acid is added to free cysteine residues of proteins, is a reversible protein modification that can affect the expression, membrane localization, and function of the modified proteins. Various diseases like Huntington's and Alzheimer's disease have been linked to changes in protein palmitoylation. In humans, the addition of palmitic acid is mediated by 23 palmitoyl acyltransferases, also called DHHC proteins. The modification can be reversed by a few thioesterases or hydrolases. Numerous soluble and membrane-attached proteins are known to be palmitoylated, but among the approximately 400 solute carriers that are classified in 66 families, only 15 found in 8 families have so far been documented to be palmitoylated. Among the best-characterized transporters are the glucose transporters GLUT1 (SLC2A1) and GLUT4 (SLC2A4), the three monoamine transporters norepinephrine transporter (NET; SLC6A2), dopamine transporter (DAT; SLC6A3), and serotonin transporter (SERT; SLC6A4), and the sodium-calcium exchanger NCX1 (SLC8A1). While there is evidence from recent proteomics experiments that numerous solute carriers are palmitoylated, no details beyond the 15 transporters covered in this review are available.
Topics: Humans; Palmitic Acid; Lipoylation; Protein Processing, Post-Translational; Phosphorylation; Membrane Proteins; Serotonin Plasma Membrane Transport Proteins
PubMed: 37481134
DOI: 10.1016/j.bcp.2023.115695 -
Journal of Cellular and Molecular... Jan 2020Both PNPLA3 I148M and hepatic inflammation are associated with nonalcoholic fatty liver disease (NAFLD) progression. This study aimed to elucidate whether PNPLA3 I148M...
Both PNPLA3 I148M and hepatic inflammation are associated with nonalcoholic fatty liver disease (NAFLD) progression. This study aimed to elucidate whether PNPLA3 I148M is involved in NF-kB-related inflammation regulation in NAFLD. HepG2 cells homozygous for the PNPLA3 I148M mutation were used. The human PNPLA3 promoter sequence was screened for NF-kB binding sites using the MATCH and PATCH tools. NF-kB-mediated transcriptional regulation of the PNPLA3 gene was assessed by luciferase reporter assay, EMSA and ChIP-qPCR. Wild-type (I148I) and mutant (M148M) PNPLA3 were overexpressed using stable lentivirus-mediated transfection. The pCMV vector and siRNA were transiently transfected into cells to direct NF-kB overexpression and PNPLA3 silencing, respectively. A putative NF-kB binding site in the human PNPLA3 promoter was shown to be necessary for basal and NF-kB-driven transcriptional activation of PNPLA3 and protein/DNA complex formation. Supershift analysis demonstrated a protein/DNA complex specifically containing the NF-kB p65 and p50 subunits. ChIP-qPCR confirmed the endogenous binding of NF-kB to the human PNPLA3 promoter in response to NF-kB overexpression and palmitic acid (PA) challenge. The silencing of PNPLA3 blocked the overexpression of NF-kB or PA-induced TNF-α up-regulation. Moreover, mutant PNPLA3 overexpression prevented NF-kB inhibitor-induced down-regulation of TNF-α expression in PA-treated HepG2 cells. Finally, the overexpression of mutant but not wild-type PNPLA3 increased TNF-α expression and activated the ER stress-mediated and NF-kB-independent inflammatory IRE-1α/JNK/c-Jun pathway. Human PNPLA3 was shown to be a target of NF-kB, and PNPLA3 I148M mediated the regulatory effect of NF-kB on inflammation in PA-treated HepG2 cells, most likely via the IRE-1α/JNK/c-Jun ER stress pathway.
Topics: Base Sequence; Binding Sites; Endoplasmic Reticulum Stress; Endoribonucleases; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Inflammation; JNK Mitogen-Activated Protein Kinases; Lipase; Membrane Proteins; Models, Biological; NF-kappa B; Palmitic Acid; Polymorphism, Single Nucleotide; Promoter Regions, Genetic; Protein Binding; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-jun; Signal Transduction; Tumor Necrosis Factor-alpha
PubMed: 31793207
DOI: 10.1111/jcmm.14839 -
International Journal of Molecular... Apr 2022Patients with psoriasis are frequently complicated with metabolic syndrome; however, it is not fully understood how obesity and dyslipidemia contribute to the...
Patients with psoriasis are frequently complicated with metabolic syndrome; however, it is not fully understood how obesity and dyslipidemia contribute to the pathogenesis of psoriasis. To investigate the mechanisms by which obesity and dyslipidemia exacerbate psoriasis using murine models and neonatal human epidermal keratinocytes (NHEKs), we used wild-type and -deficient dyslipidemic mice, and administered a high-fat diet for 10 weeks to induce obesity. Imiquimod was applied to the ear for 5 days to induce psoriatic dermatitis. To examine the innate immune responses of NHEKs, we cultured and stimulated NHEKs using IL-17A, TNF-α, palmitic acid, and leptin. We found that obesity and dyslipidemia synergistically aggravated psoriatic dermatitis associated with increased gene expression of pro-inflammatory cytokines and chemokines. Treatment of NHEKs with palmitic acid and leptin amplified pro-inflammatory responses in combination with TNF-α and IL-17A. Additionally, pretreatment with palmitic acid and leptin enhanced IL-17A-mediated c-Jun N-terminal kinase phosphorylation. These results revealed that obesity and dyslipidemia synergistically exacerbate psoriatic skin inflammation, and that metabolic-disorder-associated inflammatory factors, palmitic acid, and leptin augment the activation of epidermal keratinocytes. Our results emphasize that management of concomitant metabolic disorders is essential for preventing disease exacerbation in patients with psoriasis.
Topics: Animals; Dermatitis; Dyslipidemias; Humans; Inflammation; Interleukin-17; Keratinocytes; Leptin; Mice; Obesity; Palmitic Acid; Psoriasis; Skin; Tumor Necrosis Factor-alpha
PubMed: 35457132
DOI: 10.3390/ijms23084312 -
Cell Reports. Medicine Mar 2023Dysregulated maternal fatty acid metabolism increases the risk of congenital heart disease (CHD) in offspring with an unknown mechanism, and the effect of folic acid...
Dysregulated maternal fatty acid metabolism increases the risk of congenital heart disease (CHD) in offspring with an unknown mechanism, and the effect of folic acid fortification in preventing CHD is controversial. Using gas chromatography coupled to either a flame ionization detector or mass spectrometer (GC-FID/MS) analysis, we find that the palmitic acid (PA) concentration increases significantly in serum samples of pregnant women bearing children with CHD. Feeding pregnant mice with PA increased CHD risk in offspring and cannot be rescued by folic acid supplementation. We further find that PA promotes methionyl-tRNA synthetase (MARS) expression and protein lysine homocysteinylation (K-Hcy) of GATA4 and results in GATA4 inhibition and abnormal heart development. Targeting K-Hcy modification by either genetic ablation of Mars or using N-acetyl-L-cysteine (NAC) decreases CHD onset in high-PA-diet-fed mice. In summary, our work links maternal malnutrition and MARS/K-Hcy with the onset of CHD and provides a potential strategy in preventing CHD by targeting K-Hcy other than folic acid supplementation.
Topics: Animals; Female; Humans; Mice; Pregnancy; Folic Acid; Heart Defects, Congenital; Myocardial Infarction; Palmitic Acid; Signal Transduction
PubMed: 36809766
DOI: 10.1016/j.xcrm.2023.100953