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Qie R, Li Q, Zhao Y, Han M, Liu D, Guo C, Zhou Q, Tian G, Huang S, Wu X, Zhang Y, Qin P, Li H, Wang J, Cheng R, Lin J, Sun X, Wu Y, Li Y, Yang X, Zhao Y, Feng Y, Zhang M, Hu D. Association of hypertriglyceridemic waist-to-height ratio and its dynamic status with risk of type 2 diabetes mellitus: The Rural Chinese Cohort Study. Diabetes Res Clin Pract 2021; 179:108997. [PMID: 34371063 DOI: 10.1016/j.diabres.2021.108997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/25/2021] [Accepted: 08/04/2021] [Indexed: 11/29/2022]
Abstract
AIMS To evaluate the risk of type 2 diabetes mellitus (T2DM) in a prospective study with hypertriglyceridemic waist-to-height ratio (HWHtR) and its dynamic status. METHODS We collected data for 12,248 participants ≥18 years in this study. Cox's proportional-hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for T2DM risk by baseline HWHtR. Multiple logistic regression analysis was used to estimate odds ratios (ORs) and 95% CIs for T2DM risk by transformation in HWHtR. RESULTS We identified 839 T2DM cases during a median follow-up of 5.92 years. Compared with normal TG level and normal WHtR, T2DM risk was increased with high TG level and high WHtR (aHR 2.04, 95% CI 1.49-2.79). Similar results were observed in subgroup analyses by sex and age. During follow-up, T2DM risk was increased with stable high TG level and high WHtR (aOR 4.45, 95% CI 2.76-7.17) compared with stable normal TG level and normal WHtR. The results above were robust in sensitivity analyses. CONCLUSIONS HWHtR phenotype and its dynamic status were associated with risk of T2DM. Our study suggests that primary prevention and avoiding the appearance of the HWHtR phenotype in the rural Chinese population may reduce the T2DM risk.
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Affiliation(s)
- Ranran Qie
- Department of Endocrinology, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, PR China.; Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Quanman Li
- Department of Endocrinology, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, PR China.; Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Yang Zhao
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Minghui Han
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Dechen Liu
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Chunmei Guo
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Qionggui Zhou
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Gang Tian
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Shengbing Huang
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Xiaoyan Wu
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Yanyan Zhang
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Pei Qin
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Honghui Li
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Jian Wang
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Ruirong Cheng
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Jinchun Lin
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Xizhuo Sun
- Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Yuying Wu
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Yang Li
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Xingjin Yang
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Yang Zhao
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Yifei Feng
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Ming Zhang
- School of Public Health, Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China
| | - Dongsheng Hu
- Department of Endocrinology, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, PR China.; Study Team of Shenzhen's Sanming Project, The Affiliated Luohu Hospital of Shenzhen University Health Science Center, Shenzhen, Guangdong, People's Republic of China.
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ChaiQi Decoction Alleviates Vascular Endothelial Injury by Downregulating the Inflammatory Response in ApoE-Model Mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:9415819. [PMID: 33628325 PMCID: PMC7889348 DOI: 10.1155/2021/9415819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 12/29/2020] [Accepted: 01/09/2021] [Indexed: 11/30/2022]
Abstract
Metabolic syndrome (MetS) is a pathological state of metabolic disorders that primarily occur in human proteins, fats, and carbohydrates. It is a complex cluster of core metabolic disorder syndromes including obesity, hyperglycemia, dyslipidemia, and hypertension, and vascular endothelial injury, occurring over time. The currently available treatment options cannot effectively manage MetS. In our previous research, we revealed ChaiQi decoction (CQD) as an effective prescription for improving MetS; however, the specific mechanism remains unclear. Herein, we assessed the efficacy and mechanism of CQD in ApoE gene knockout (ApoE-) mice. Mice were administered with CQD daily for 12 weeks, and the measurement of their body weight was taken monthly. To evaluate the metabolic levels of mice, we determined the fasting blood glucose (FBG), fasting serum insulin (FINS), insulin resistance index (IRI), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels. Furthermore, immunohistochemical analysis was adopted to determine the expression of ICAM-1 and VCAM-1 in vascular endothelium, while an optical microscope was adopted to observe the pathological morphology of abdominal aorta in mice. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) levels were determined using the ELISA method, whereas Western blotting was used to determine nuclear factor- (NF-) κB p65. Of note, intragastric CQD administration ameliorated ApoE-model mice, as evidenced by reduced levels of FBG, FINS, IRI, TG, TC, and LDL-C. Furthermore, CQD alleviated vascular endothelial injury and regularized the structure of the abdominal aorta by downregulating the expressions of proinflammatory cytokines TNF-α, IL-6, ICAM-1, VCAM-1, and NF-κB p65. Overall, these findings advocated that CQD ameliorates metabolic levels and vascular endothelial injury in mice by downregulating the inflammatory response and thus may be utilized as a novel MetS therapy.
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Xia MF, Lin HD, Chen LY, Wu L, Ma H, Li Q, Aleteng Q, Chen Y, Sun YX, Hu Y, Pan BS, Li XY, Gao X. Association of visceral adiposity and its longitudinal increase with the risk of diabetes in Chinese adults: A prospective cohort study. Diabetes Metab Res Rev 2018; 34:e3048. [PMID: 30035847 DOI: 10.1002/dmrr.3048] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 07/04/2018] [Accepted: 07/15/2018] [Indexed: 12/31/2022]
Abstract
OBJECTIVE A Chinese visceral adiposity index (CVAI) was recently established to estimate the visceral fat area in Chinese adults. This study aimed to investigate the risk of incident prediabetes and diabetes in relation to visceral adiposity calculated by CVAI. METHODS A total of 2558 subjects with normal plasma glucose levels from the Shanghai Changfeng Study were enrolled in a prospective cohort study. The independent associations of basal visceral fat area by CVAI and its longitudinal change with incident prediabetes and diabetes were identified using Cox regression analyses. RESULTS During an average of 4.4 years of follow-up, 546 (21.3%) and 99 (3.9%) of 2558 nondiabetic subjects developed prediabetes and diabetes, respectively. Visceral fat area by CVAI and its longitudinal increase were independently associated with incident prediabetes and diabetes in Chinese adults. In a multivariable-adjusted regression model, CVAI, as well as its annual change, was the strongest independent predictor of incident prediabetes (HR, 1.383 [1.162-1.647]) and diabetes (HR, 1.607 [1.092-2.364]) compared with other estimates of obesity (BMI and waist circumference). Receiver operating characteristic curve analyses showed that CVAI had better performance than BMI and waist circumference for the prediction of prediabetes and diabetes in Chinese adults. CONCLUSIONS Visceral adiposity plays a pivotal role in the pathogenesis of diabetes, and the visceral adiposity estimated by CVAI is superior to the traditional estimates of obesity for the prediction of incident prediabetes and diabetes in Chinese adults.
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Affiliation(s)
- Ming-Feng Xia
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Huan-Dong Lin
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Ling-Yan Chen
- Department of Geriatrics, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Li Wu
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Hui Ma
- Department of Geriatrics, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qian Li
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Qiqige Aleteng
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Ying Chen
- Department of Endocrinology and Metabolism, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Yi-Xuan Sun
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Yu Hu
- Department of Geriatrics, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Bai-Shen Pan
- Department of Laboratory Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiao-Ying Li
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China
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Shin S, Seong JK, Bae YS. Ahnak stimulates BMP2-mediated adipocyte differentiation through Smad1 activation. Obesity (Silver Spring) 2016; 24:398-407. [PMID: 26813528 DOI: 10.1002/oby.21367] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/09/2015] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Previous reports have indicated that Ahnak-deficient mice were protected from high-fat diet-induced obesity. However, the molecular mechanism in which Ahnak mediates adipocyte differentiation and high-fat diet-induced obesity is unclear. METHODS Adipocytes from Ahnak knockout (Ahnak(-/-) ) mice and knockdown of Ahnak in C3H10T1/2 were used to investigate the function of Ahnak in adipocyte differentiation. Ahnak-induced adipocyte differentiation was analyzed by Oil Red O staining. RESULTS Adipocytes from Ahnak(-/-) mice were smaller than those from wild-type mice. Silencing of Ahnak in C3H10T1/2 and adipose tissue-derived mesenchymal stem cells (ADSCs) from Ahnak(-/-) mice showed severely impaired adipocyte differentiation. Down-regulation of Ahnak in C3H10T1/2 cells and ADSCs from Ahnak(-/-) mice attenuated the phosphorylation and nuclear localization of Smad1 in response to BMP2, whereas Ahnak overexpression in 3T3-L1 cells significantly increased Smad1 activation. Because PPARγ is a well-known transcriptional factor in adipocyte differentiation, the PPARγ expression in Ahnak-mediated adipocyte differentiation was investigated. Transfection of C3H10T1/2 cells with Ahnak siRNA resulted in reduced PPARγ expression apparently through inhibited binding of Smad1 to the Smad1-binding site in the PPARγ promoter. These results suggest that Ahnak regulates adipogenesis by regulating Smad1-dependent PPARγ expression. CONCLUSIONS A molecular mechanism was proposed in which Ahnak regulates adipocyte differentiation through Smad1 activation.
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Affiliation(s)
- Sunmee Shin
- Department of Life Science, Ewha Womans University, Seoul, Korea
| | - Je Kyung Seong
- Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, and BK21 Program for Veterinary Science, Seoul National University, Daehak-Dong, Gwanak-Gu, Seoul, Korea
| | - Yun Soo Bae
- Department of Life Science, Ewha Womans University, Seoul, Korea
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Chen C, Du J, Feng W, Song Y, Lu Z, Xu M, Li Z, Zhang Y. β-Adrenergic receptors stimulate interleukin-6 production through Epac-dependent activation of PKCδ/p38 MAPK signalling in neonatal mouse cardiac fibroblasts. Br J Pharmacol 2012; 166:676-88. [PMID: 22103274 DOI: 10.1111/j.1476-5381.2011.01785.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE IL-6 plays crucial roles in cardiac hypertrophy, cardiac fibrosis and heart failure. Activation of β-adrenoceptors induced IL-6 production in neonatal mouse cardiac fibroblasts (NMCFs) through a G(s) /adenylate cyclase/cAMP/p38 MAPK pathway but independent of PKA. However, how cAMP activates p38 MAPK is still not defined. In this study, we have assessed the role of the exchange protein directly activated by cAMP (Epac) and PKCδ in p38 MAPK activation and IL-6 production by stimulated by the β-adrenoceptor agonist isoprenaline in NMCFs. EXPERIMENTAL APPROACH The IL-6 concentration in cell culture supernatants was measured by ELISA. The levels of phosphorylated and total p38 MAPK and PKCδ were determined by Western blot analysis. The translocation of PKCδ was determined by immunoblotting the soluble and particulate fractions. Expression of Epac1 or PKCδ was knocked down by the corresponding, adenovirus-mediated, small hairpin RNA (shRNA). RESULTS In NMCFs, activation of β-adrenoceptors enhanced PKCδ phosphorylation and translocation. Furthermore, knock-down of the PKCδ isoform using an adenovirus-mediated shRNA markedly down-regulated IL-6 induction by NMCFs stimulated with isoprenaline. Moreover, knock-down of Epac1 confirmed that Epac1 was upstream of PKCδ in IL-6 production. Additionally, both Epac1 and PKCδ mediated the p38 MAPK activation induced by isoprenaline. CONCLUSIONS AND IMPLICATIONS β-Adrenoceptor agonists activate a cAMP/Epac/PKCδ/p38 MAPK pathway to produce IL-6 in NMCFs. This study identifies Epac as the link between cAMP and p38 MAPK signalling pathways and demonstrates that PKCδ can function as a novel downstream effector of this β-adrenoceptor/cAMP/Epac pathway.
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Affiliation(s)
- Chao Chen
- Institute of Vascular Medicine, Peking University Third Hospital, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health and Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
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Higa JK, Panee J. Bamboo extract reduces interleukin 6 (IL-6) overproduction under lipotoxic conditions through inhibiting the activation of NF-κB and AP-1 pathways. Cytokine 2011; 55:18-23. [PMID: 21474329 DOI: 10.1016/j.cyto.2011.02.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 02/02/2011] [Accepted: 02/19/2011] [Indexed: 12/11/2022]
Abstract
Interleukin 6 (IL-6) is an inflammatory cytokine overexpressed in obese individuals that contributes to the development of diseases such as insulin resistance, type 2 diabetes, and cardiovascular disease. This study investigated the inhibitory effect of an extract from the bamboo Phyllostachys edulis (BEX) on lipotoxicity-induced over-production of IL-6 in metabolic cell lines. Palmitic acid (PA, 0.4mM) was used to induce lipotoxicity in murine C2C12, 3T3-L1, and Hepa6 cells. Both intra- and extra-cellular protein concentrations of IL-6 were measured in the three cell lines after PA treatment with or without the presence of BEX using cytometric bead assays. IL-6 mRNA levels were quantified using real-time PCR, and nuclear concentrations of c-fos, p50 and p65 proteins were measured using DNA-binding ELISA in 3T3-L1 cells. Lipotoxicity increased IL-6 protein concentration in both cytosol and media collected from myoblast and myotube C2C12, as well as preadipose and adipose 3T3-L1, and the presence of BEX (0.5%, v/v) effectively inhibited this overproduction. IL-6 protein expression in hepatic Hepa6 cells was less affected by lipotoxicity. BEX significantly ameliorated PA-induced upregulation of IL-6 mRNA, which correlated with a reduction in nuclear translocation of p50, p65, and c-fos proteins with the presence of BEX, indicating inhibition of NF-κB and AP-1 activation. In summary, BEX inhibits lipotoxicity-induced IL-6 overproduction in muscle and adipose cell lines through the NF-κB and AP-1 pathways, implicating a potential application of this natural product as a cost-effective anti-inflammation nutraceutical.
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Affiliation(s)
- Jason K Higa
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street BSB 222, Honolulu, HI 96813, USA
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Wong CK, Ho AWY, Tong PCY, Yeung CY, Kong APS, Lun SWM, Chan JCN, Lam CWK. Aberrant activation profile of cytokines and mitogen-activated protein kinases in type 2 diabetic patients with nephropathy. Clin Exp Immunol 2007; 149:123-31. [PMID: 17425653 PMCID: PMC1942021 DOI: 10.1111/j.1365-2249.2007.03389.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cytokine-induced inflammation is involved in the pathogenesis of type 2 diabetes mellitus (DM). We investigated plasma concentrations and ex vivo production of cytokines and chemokines, and intracellular signalling molecules, mitogen-activated protein kinases (MAPK) in T helper (Th) cells and monocytes in 94 type 2 diabetic patients with or without nephropathy and 20 healthy controls. Plasma concentrations of inflammatory cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-18 and chemokine CCL2 in patients with diabetic nephropathy (DN) were significantly higher than control subjects, while IL-10, CXCL8, CXCL9, CXCL10 and adiponectin concentrations of DN were significantly higher than patients without diabetic nephropathy (NDN) and control subjects (all P < 0.05). Plasma concentrations of TNF-alpha, IL-6, IL-10, IL-18, CCL2, CXCL8, CXCL9, CXCL10 and adiponectin exhibited significant positive correlation with urine albumin : creatinine ratio in DN patients. The percentage increases of ex vivo production of IL-6, CXCL8, CXCL10, CCL2 and CCL5 upon TNF-alpha activation were significantly higher in both NDN and DN patients than controls (all P < 0.05). The percentage increases in IL-18-induced phosphorylation of extracellular signal-regulated kinase (ERK) in Th cells of NDN and DN were significantly higher than controls (P < 0.05), while the percentage increase in TNF-alpha-induced phosphorylation of p38 MAPK in monocytes and IL-18-induced phosphorylation of p38 MAPK in Th cells and monocytes were significantly higher in NDN patients than controls. These results confirmed that the aberrant production of inflammatory cytokines and chemokines and differential activation of MAPK in different leucocytes are the underlying immunopathological mechanisms of type 2 DM patients with DN.
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Affiliation(s)
- C K Wong
- Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China
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Samuel VT, Liu ZX, Wang A, Beddow SA, Geisler JG, Kahn M, Zhang XM, Monia BP, Bhanot S, Shulman GI. Inhibition of protein kinase Cepsilon prevents hepatic insulin resistance in nonalcoholic fatty liver disease. J Clin Invest 2007; 117:739-45. [PMID: 17318260 PMCID: PMC1797607 DOI: 10.1172/jci30400] [Citation(s) in RCA: 376] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Accepted: 01/03/2007] [Indexed: 12/25/2022] Open
Abstract
Nonalcoholic fatty liver disease is strongly associated with hepatic insulin resistance and type 2 diabetes mellitus, but the molecular signals linking hepatic fat accumulation to hepatic insulin resistance are unknown. Three days of high-fat feeding in rats results specifically in hepatic steatosis and hepatic insulin resistance. In this setting, PKCepsilon, but not other isoforms of PKC, is activated. To determine whether PKCepsilon plays a causal role in the pathogenesis of hepatic insulin resistance, we treated rats with an antisense oligonucleotide against PKCepsilon and subjected them to 3 days of high-fat feeding. Knocking down PKCepsilon expression protects rats from fat-induced hepatic insulin resistance and reverses fat-induced defects in hepatic insulin signaling. Furthermore, we show that PKCepsilon associates with the insulin receptor in vivo and impairs insulin receptor kinase activity both in vivo and in vitro. These data support the hypothesis that PKCepsilon plays a critical role in mediating fat-induced hepatic insulin resistance and represents a novel therapeutic target for type 2 diabetes.
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Affiliation(s)
- Varman T. Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Zhen-Xiang Liu
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Amy Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sara A. Beddow
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - John G. Geisler
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Mario Kahn
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Xian-man Zhang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Brett P. Monia
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sanjay Bhanot
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Veterans Administration Medical Center, West Haven, Connecticut, USA.
Isis Pharmaceuticals Inc., Carlsbad, California, USA.
Department of Cellular and Molecular Physiology and
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
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Samuel VT, Liu ZX, Wang A, Beddow SA, Geisler JG, Kahn M, Zhang XM, Monia BP, Bhanot S, Shulman GI. Inhibition of protein kinase Cepsilon prevents hepatic insulin resistance in nonalcoholic fatty liver disease. J Clin Invest 2007. [PMID: 17318260 DOI: 10.1172/jci3040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Nonalcoholic fatty liver disease is strongly associated with hepatic insulin resistance and type 2 diabetes mellitus, but the molecular signals linking hepatic fat accumulation to hepatic insulin resistance are unknown. Three days of high-fat feeding in rats results specifically in hepatic steatosis and hepatic insulin resistance. In this setting, PKCepsilon, but not other isoforms of PKC, is activated. To determine whether PKCepsilon plays a causal role in the pathogenesis of hepatic insulin resistance, we treated rats with an antisense oligonucleotide against PKCepsilon and subjected them to 3 days of high-fat feeding. Knocking down PKCepsilon expression protects rats from fat-induced hepatic insulin resistance and reverses fat-induced defects in hepatic insulin signaling. Furthermore, we show that PKCepsilon associates with the insulin receptor in vivo and impairs insulin receptor kinase activity both in vivo and in vitro. These data support the hypothesis that PKCepsilon plays a critical role in mediating fat-induced hepatic insulin resistance and represents a novel therapeutic target for type 2 diabetes.
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Affiliation(s)
- Varman T Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
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10
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Samuel VT, Liu ZX, Wang A, Beddow SA, Geisler JG, Kahn M, Zhang XM, Monia BP, Bhanot S, Shulman GI. Inhibition of protein kinase Cepsilon prevents hepatic insulin resistance in nonalcoholic fatty liver disease. J Clin Invest 2007. [PMID: 17318260 DOI: 10.1172/jci130400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nonalcoholic fatty liver disease is strongly associated with hepatic insulin resistance and type 2 diabetes mellitus, but the molecular signals linking hepatic fat accumulation to hepatic insulin resistance are unknown. Three days of high-fat feeding in rats results specifically in hepatic steatosis and hepatic insulin resistance. In this setting, PKCepsilon, but not other isoforms of PKC, is activated. To determine whether PKCepsilon plays a causal role in the pathogenesis of hepatic insulin resistance, we treated rats with an antisense oligonucleotide against PKCepsilon and subjected them to 3 days of high-fat feeding. Knocking down PKCepsilon expression protects rats from fat-induced hepatic insulin resistance and reverses fat-induced defects in hepatic insulin signaling. Furthermore, we show that PKCepsilon associates with the insulin receptor in vivo and impairs insulin receptor kinase activity both in vivo and in vitro. These data support the hypothesis that PKCepsilon plays a critical role in mediating fat-induced hepatic insulin resistance and represents a novel therapeutic target for type 2 diabetes.
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Affiliation(s)
- Varman T Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
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Torres LM, Cefaratti C, Perry B, Romani A. Involvement of ERK1/2 and p38 in Mg2+ accumulation in liver cells. Mol Cell Biochem 2006; 288:191-9. [PMID: 16652208 DOI: 10.1007/s11010-006-9139-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Accepted: 01/17/2006] [Indexed: 10/24/2022]
Abstract
Activation of PKC signaling induces Mg(2+) accumulation in liver cells. To test the hypothesis that PKC induces Mg(2+) accumulation via MAPKs activation, hepatocytes were incubated in the presence of PD98059 and SB202190 as specific inhibitors of ERK1/2 and p38, respectively, and stimulated for Mg(2+) accumulation by addition of PMA or OAG. Accumulation of Mg(2+) within the cells was measured by atomic absorbance spectrophotometry in the acid extract of cell pellet. The presence of either inhibitor completely abolished Mg(2+) accumulation irrespective of the dose of agonist utilized while having no discernible effect on beta -adrenoceptor mediated Mg(2+) extrusion. A partial inhibition on alpha (1)-adrenoceptor mediated Mg(2+) extrusion was observed only in cells treated with PD98059. To confirm the inhibitory effect of PD98509 and SB202190, total and basolateral liver plasma membrane vesicles were purified in the presence of either MAPK inhibitor during the isolation procedure. Consistent with the data obtained in intact cells, liver plasma membrane vesicles purified in the presence of PD98509 or SB202190 lost the ability to accumulate Mg(2+)in exchange for intra-vesicular entrapped Na(+) while retaining the ability to extrude entrapped Mg(2+) in exchange for extra-vesicular Na(+). These data indicate that ERK1/2 and p38 are involved in mediating Mg(2+) accumulation in liver cells following activation of PKC signaling. The absence of a detectable effect of either inhibitor on beta -adrenoceptor induced, Na(+)-dependent Mg(2+) extrusion in intact cells and in purified plasma membrane vesicles further support the hypothesis that Mg(2+) extrusion and accumulation occur through distinct and differently regulated transport mechanisms.
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Affiliation(s)
- Lisa M Torres
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, USA
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Lessmann E, Leitges M, Huber M. A redundant role for PKC-epsilon in mast cell signaling and effector function. Int Immunol 2006; 18:767-73. [PMID: 16569674 DOI: 10.1093/intimm/dxl012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Protein kinase (PK) C-epsilon is strongly expressed in mast cells (MCs) and activated in response to antigen-mediated high-affinity receptor for IgE (Fc epsilonR1) engagement. A critical role of PKC-epsilon in antigen-triggered activation of various signaling pathways was observed in basophilic leukemia cells. To study the function of PKC-epsilon in MCs differentiated in vitro from murine bone marrow, we used our established PKC-epsilon null mice. Unexpectedly, we did not reveal any difference in antigen-induced activation of many central signaling molecules (PKB, mitogen-activated protein kinase, p38, Jun-N-terminal kinase, phospholipase C-gamma1, Bruton's tyrosine kinase, PKD, Fos and PKC-delta) in time-course as well as dose-response studies between PKC-epsilon-deficient and wild-type MCs. In correlation, antigen-triggered degranulation, release of arachidonic acid and secretion of IL-6 were unaltered by the loss of PKC-epsilon. Furthermore, stimulation of MCs via different receptor systems [Steel factor receptor (c-kit) and toll-like receptor 4] did not lead to differences in the measured responses between both cell types. These results strongly suggest that PKC-epsilon plays a redundant role in MCs stimulated by antigen as well as other well-known MC stimuli.
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Affiliation(s)
- Eva Lessmann
- Department of Molecular Immunology, Institute for Biology III, University of Freiburg and Max Planck Institute for Immunobiology, Stübeweg 51, 79108 Freiburg, Germany
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Waters CE, Shi-Wen X, Denton CP, Abraham DJ, Pearson JD. Signaling pathways regulating intercellular adhesion molecule 1 expression by endothelin 1: Comparison with interleukin-1β in normal and scleroderma dermal fibroblasts. ACTA ACUST UNITED AC 2006; 54:649-60. [PMID: 16447227 DOI: 10.1002/art.21572] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Endothelin 1 (ET-1) has been implicated in the pathogenesis of fibrotic and inflammatory diseases, including scleroderma. In addition to modulating vascular tone and extracellular matrix turnover, ET-1 up-regulates cell surface adhesion molecules including intercellular adhesion molecule 1 (ICAM-1), which is key to cell-cell and cell-matrix adhesion and leukocyte infiltration. This study was undertaken to delineate the signal transduction pathways utilized by ET-1 and compare them with those adopted by proinflammatory cytokine interleukin-1beta (IL-1beta) in normal and scleroderma dermal fibroblasts. METHODS Protein expression induced by ET-1 and IL-1beta on normal dermal fibroblasts, with or without signaling inhibitors, was detected by enzyme-linked immunosorbent assay, while messenger RNA (mRNA) levels were analyzed by LightCycler polymerase chain reaction. Expression of protein kinase Cdelta (PKCdelta) and PKCepsilon protein in normal dermal fibroblasts and scleroderma dermal fibroblasts was determined by Western blotting, and PKCepsilon involvement in ET-1 signaling was confirmed through transfection of an ICAM-1 promoter construct into murine PKCepsilon-/- fibroblasts. NF-kappaB activation was confirmed via electrophoretic mobility supershift assay, and analysis of the ICAM-1 promoter region was achieved via transfection of deletion constructs into human dermal fibroblasts. RESULTS In normal dermal fibroblasts, ET-1 induced ICAM-1 mRNA and surface protein expression in a dose- and time-dependent manner via both receptor subtypes, ET(A) and ET(B); antagonism of both abolished the ET-1 response. MEK was involved in the signaling cascade, but phosphatidylinositol 3-kinase and p38 MAPK were not. Key to the cascade was activation of NF-kappaB, achieved by ligation of either receptor subtype. PKCepsilon activation led to downstream activation of MEK and, in part, NF-kappaB. IL-1beta signaling required NF-kappaB and MEK activation, along with activation of PKCdelta. ET-1 and IL-1beta each utilized the same ICAM-1 promoter region and the same NF-kappaB site at -157 bp. Responses to ET-1 and IL-1beta differed in scleroderma dermal fibroblasts, with ET-1 sensitivity decreasing and IL-1beta responses remaining intact. Expression of PKCepsilon and PKCdelta in scleroderma dermal fibroblasts was also altered. CONCLUSION The findings of this study indicate that differences in sensitivity to ET-1 and IL-1beta in scleroderma dermal fibroblasts may be explained by altered expression of the PKC isoforms and cytokine receptors.
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