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Feng L, Wang S, Chen F, Zhang C, Wang Q, Zhao Y, Zhang Z. Hepatic Knockdown of Endothelin Type A Receptor (ETAR) Ameliorates Hepatic Insulin Resistance and Hyperglycemia Through Suppressing p66Shc-Mediated Mitochondrial Fragmentation in High-Fat Diet-Fed Mice. Diabetes Metab Syndr Obes 2021; 14:963-981. [PMID: 33688230 PMCID: PMC7936928 DOI: 10.2147/dmso.s299570] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/23/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Emerging evidence from animal studies and clinical trials indicates that systemic inhibition of endothelin1 (ET1) signaling by endothelin receptor antagonists improves pathological features of diabetes and its complications. It is indicated that endothelin type A receptor (ETAR) plays a major role in ET1-mediated pathophysiological actions including diabetic pathology. However, the effects as well as the mechanistic targets of hepatic ET1/ETAR signaling inhibition on the pathology of metabolic diseases remain unclear. This study aimed to investigate the beneficial effects as well as the underlying mechanisms of hepatic ETAR knockdown on metabolism abnormalities in high-fat diet (HFD)-fed mice. METHODS Mice were fed a HFD to induce insulin resistance and metabolism abnormalities. L02 cells were treated with ET1 to assess the action of ET1/ETAR signaling in vitro. Liver-selective knockdown of ETAR was achieved by tail vein injection of adeno-associated virus 8 (AAV8). Systemic and peripheral metabolism abnormalities were determined in vivo and in vitro. Mitochondrial fragmentation was observed by transmission electron microscope (TEM) and mitoTracker red staining. RESULTS Here we provided in vivo and in vitro evidence to demonstrate that liver-selective knockdown of ETAR effectively ameliorated hepatic insulin resistance and hyperglycemia in HFD-fed mice. Mechanistically, hepatic ETAR knockdown alleviated mitochondrial fragmentation and dysfunction via inactivating 66-kDa Src homology 2 domain-containing protein (p66Shc) to recover mitochondrial dynamics, which was mediated by inhibiting protein kinase Cδ (PKCδ), in the livers of HFD-fed mice. Ultimately, hepatic ETAR knockdown attenuated mitochondria-derived oxidative stress and related liver injuries in HFD-fed mice. These ETAR knockdown-mediated actions were confirmed in ET1-treated L02 cells. CONCLUSION This study defined an ameliorative role of hepatic ETAR knockdown in HFD-induced metabolism abnormalities by alleviating p66Shc-mediated mitochondrial fragmentation and consequent oxidative stress-related disorders and indicated that hepatic ETAR knockdown may be a promising therapeutic strategy for metabolic diseases.
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Affiliation(s)
- Li Feng
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
| | - Songhua Wang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
| | - Feng Chen
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
| | - Cheng Zhang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
| | - Qiao Wang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
| | - Yuting Zhao
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
| | - Zifeng Zhang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, People’s Republic of China
- Correspondence: Zifeng Zhang 101 Shanghai Road, Xuzhou, Jiangsu Province, 221116, People’s Republic of ChinaTel + 86 516 83403729 Email
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Banerjee M, Khursheed R, Yadav AK, Singh SK, Gulati M, Pandey DK, Prabhakar PK, Kumar R, Porwal O, Awasthi A, Kumari Y, Kaur G, Ayinkamiye C, Prashar R, Mankotia D, Pandey NK. A Systematic Review on Synthetic Drugs and Phytopharmaceuticals Used to Manage Diabetes. Curr Diabetes Rev 2020; 16:340-356. [PMID: 31438829 DOI: 10.2174/1573399815666190822165141] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/15/2019] [Accepted: 08/04/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Diabetes is a multifactorial disease and a major cause for many microvascular and macrovascular complications. The disease will ultimately lead to high rate mortality if it is not managed properly. Treatment of diabetes without any side effects has always remained a major challenge for health care practitioners. INTRODUCTION The current review discusses the various conventional drugs, herbal drugs, combination therapy and the use of nutraceuticals for the effective management of diabetes mellitus. The biotechnological aspects of various antidiabetic drugs are also discussed. METHODS Structured search of bibliographic databases for previously published peer-reviewed research papers was explored and data was sorted in terms of various approaches that are used for the treatment of diabetes. RESULTS More than 170 papers including both research and review articles, were included in this review in order to produce a comprehensive and easily understandable article. A series of herbal and synthetic drugs have been discussed along with their current status of treatment in terms of dose, mechanism of action and possible side effects. The article also focuses on combination therapies containing synthetic as well as herbal drugs to treat the disease. The role of pre and probiotics in the management of diabetes is also highlighted. CONCLUSION Oral antihyperglycemics which are used to treat diabetes can cause many adverse effects and if given in combination, can lead to drug-drug interactions. The combination of various phytochemicals with synthetic drugs can overcome the challenge faced by the synthetic drug treatment. Herbal and nutraceuticals therapy and the use of probiotics and prebiotics are a more holistic therapy due to their natural origin and traditional use.
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Affiliation(s)
- Mayukh Banerjee
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Rubiya Khursheed
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Ankit Kumar Yadav
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Sachin Kumar Singh
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Monica Gulati
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Devendra Kumar Pandey
- Department of Biotechnology, Lovely Faculty of Technology and Sciences, Lovely Professional University, Phagwara 144402, Punjab, India
| | - Pranav Kumar Prabhakar
- Department of Medical Laboratory Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Rajesh Kumar
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Omji Porwal
- Faculty of Pharmacy, Ishik University, Erbil, Iraq
| | - Ankit Awasthi
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Yogita Kumari
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Gurmandeep Kaur
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Clarisse Ayinkamiye
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Rahul Prashar
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Diksha Mankotia
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
| | - Narendra Kumar Pandey
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara - 144411, Punjab, India
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Parra-Abarca J, Rivera-Ramírez N, Villa-Maldonado LF, García-Hernández U, Aguilera P, Arias-Montaño JA. Histamine H 1 and H 3 receptor activation increases the expression of Glucose Transporter 1 (GLUT-1) in rat cerebro-cortical astrocytes in primary culture. Neurochem Int 2019; 131:104565. [PMID: 31586591 DOI: 10.1016/j.neuint.2019.104565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 09/11/2019] [Accepted: 10/02/2019] [Indexed: 01/05/2023]
Abstract
Astrocytes take up glucose via the 45 kDa isoform of the Glucose Transporter 1 (GLUT-1), and in this work we have investigated whether histamine regulates GLUT-1 expression in rat cerebro-cortical astrocytes in primary culture. Cultured astrocytes expressed histamine H1 and H3 receptors (H1Rs and H3Rs) as evaluated by radioligand binding. Receptor functionality was confirmed by the increase in the intracellular concentration of Ca2+ (H1R) and the inhibition of forskolin-induced cAMP accumulation (H3R). Quantitative RT-PCR showed that histamine and selective H1R and H3R agonists (1 h incubation) significantly increased GLUT-1 mRNA to 153 ± 7, 163 ± 2 and 168 ± 13% of control values, respectively. In immunoblot assays, incubation (3 h) with histamine or H1R and H3R agonists increased GLUT-1 protein levels to 224 ± 12, 305 ± 11 and 193 ± 13% of control values, respectively, an action confirmed by inmunocytochemistry. The effects of H1R and H3R agonists were blocked by the selective antagonists mepyramine (H1R) and clobenpropit (H3R). The pharmacological inhibition of protein kinase C (PKC) prevented the increase in GLUT-1 protein induced by either H1R or H3R activation. Furthermore, histamine increased ERK-1/2 phosphorylation, and the effect of H1R and H3R activation on GLUT-1 protein levels was reduced or prevented, respectively, by MEK-1/2 inhibition. These results indicate that by activating H1Rs and H3Rs histamine regulates the expression of GLUT-1 by astrocytes. The effect appears to involve the phospholipase C (PLC) → diacylglycerol (DAG)/Ca2+→ PKC and PLC → DAG/Ca2+ → PKC → MAPK pathways.
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Affiliation(s)
- Juan Parra-Abarca
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Zacatenco, 07360, Ciudad de México, Mexico
| | - Nayeli Rivera-Ramírez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Zacatenco, 07360, Ciudad de México, Mexico
| | - Luis-Fernando Villa-Maldonado
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Zacatenco, 07360, Ciudad de México, Mexico
| | - Ubaldo García-Hernández
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Zacatenco, 07360, Ciudad de México, Mexico
| | - Penélope Aguilera
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877, La Fama, 14269, Ciudad de México, Mexico
| | - José-Antonio Arias-Montaño
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Zacatenco, 07360, Ciudad de México, Mexico.
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Lien CC, Jiang JL, Jian DY, Kwok CF, Ho LT, Juan CC. Chronic endothelin-1 infusion causes adipocyte hyperplasia in rats. Obesity (Silver Spring) 2016; 24:643-53. [PMID: 26833777 DOI: 10.1002/oby.21394] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/10/2015] [Accepted: 10/03/2015] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The aim of this study was to investigate the regulatory mechanism of endothelin-1 (ET-1), an endothelium-derived vasoconstrictor, on adipogenesis in vitro and in vivo. METHODS 3T3-L1 preadipocytes were used to explore the mechanisms mediating ET-1 actions on preadipocyte proliferation and adipocyte differentiation. To investigate the in vivo effect of ET-1, male Sprague-Dawley rats were infused with ET-1 or saline for 4 weeks via intraperitoneally implanted osmotic pumps, and the fat pad weight and adipocyte size of adipose tissues were measured. RESULTS ET-1 stimulated preadipocyte proliferation and increased the cell number at the mitotic clonal expansion stage of adipocyte differentiation via the endothelin A receptor (ETAR) and activation of the protein kinase C (PKC) pathway. ET-1, via ETAR, inhibited adipocyte differentiation partially through an ERK-dependent pathway. Furthermore, no significant difference in the body weight and fat pad weight was observed in either ET-1- or saline-infused rats. Compared with saline-infused rats, the adipocyte cell number was significantly increased but the adipocyte size was significantly decreased in ET-1-infused rats. CONCLUSIONS Chronic ET-1 infusion increased the number of small adipocytes without the change of white adipose tissue mass in rats, which were associated with ET-1-stimulated preadipocyte proliferation, but not ET-1-suppressed adipocyte differentiation.
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Affiliation(s)
- Chih-Chan Lien
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Jia-Ling Jiang
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Deng-Yuan Jian
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Nephrology, Wen-Lin Hemodialysis Unit, Taipei, Taiwan
| | - Ching-Fai Kwok
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Low-Tone Ho
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chi-Chang Juan
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
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Chai SP, Fong JC. Synergistic induction of insulin resistance by endothelin-1 and cAMP in 3T3-L1 adipocytes. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2048-55. [PMID: 26143144 DOI: 10.1016/j.bbadis.2015.06.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 05/30/2015] [Accepted: 06/25/2015] [Indexed: 12/27/2022]
Abstract
Both endothelin-1 (ET-1) and cAMP are implicated for inducing insulin resistance. Since we have shown previously that there is a crosstalk between ET-1 and cAMP signaling pathways in regulating glucose uptake in 3T3-L1 adipocytes, we extended our investigation in this study on whether they may have a synergistic effect on inducing insulin resistance. Our results showed that it was indeed the case. Insulin-stimulated glucose uptake, phosphorylation of PKB, IRS-1-associated PI3K, and IRS-1 tyrosine phosphorylation were all inhibited by ET-1 and 8-bromo cAMP in a synergistic manner. IRS-1 protein levels were similarly decreased by ET-1 and 8-bromo cAMP, attributable to suppressed mRNA expression. In addition, after correction for the loss in IRS-1 protein, the inhibition of insulin-stimulated IRS-1 tyrosine phosphorylation or IRS-1-associated PI3K was mainly caused by cAMP. Moreover, whereas IRS-2 protein levels were increased by cAMP or ET-1 plus cAMP, insulin-stimulated IRS-2-associated PI3K activities were abolished by both treatments. Furthermore, ET-1 and β-adrenergic agonists had similar synergistic inhibition on insulin-stimulated glucose uptake. In conclusion, we have shown that ET-1 and cAMP may synergistically induce insulin resistance in adipocytes via inhibiting IRS-1 expression as well as insulin-stimulated IRS-1/IRS-2 activities.
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Affiliation(s)
- Shin-Pei Chai
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan, ROC
| | - Jim C Fong
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan, ROC.
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Ku HC, Tsuei YW, Kao CC, Weng JT, Shih LJ, Chang HH, Liu CW, Tsai SW, Kuo YC, Kao YH. Green tea (-)-epigallocatechin gallate suppresses IGF-I and IGF-II stimulation of 3T3-L1 adipocyte glucose uptake via the glucose transporter 4, but not glucose transporter 1 pathway. Gen Comp Endocrinol 2014; 199:46-55. [PMID: 24486085 DOI: 10.1016/j.ygcen.2014.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 01/13/2014] [Accepted: 01/17/2014] [Indexed: 01/26/2023]
Abstract
This study investigated the pathways involved in EGCG modulation of insulin-like growth factor (IGF)-stimulated glucose uptake in 3T3-L1 adipocytes. EGCG inhibited IGF-I and IGF-II stimulation of adipocyte glucose uptake with dose and time dependencies. EGCG at 20μM for 2h decreased IGF-I- and IGF-II-stimulated glucose uptake by 59% and 64%, respectively. Pretreatment of adipocytes with antibody against the EGCG receptor (also known as the 67-kDa laminin receptor; 67LR), prevented the effects of EGCG on IGF-increased glucose uptake, but pretreatment with normal rabbit immunoglobulin did not. This suggests that the 67LR mediates the anti-IGF effect of EGCG on adipocyte glucose uptake. Further analysis indicated EGCG, IGF-I, and IGF-II did not alter total levels of GLUT1 or GLUT4 protein. However, EGCG prevented the IGF-increased GLUT4 levels in the plasma membrane and blocked the IGF-decreased GLUT4 levels in low-density microsomes. Neither EGCG nor its combination with IGF altered GLUT1 protein levels in the plasma membrane and low-density microsomes. EGCG also suppressed the IGF-stimulated phosphorylation of IGF signaling molecules, PKCζ/λ, but not AKT and ERK1/2, proteins. This study suggests that EGCG suppresses IGF stimulation of 3T3-L1 adipocyte glucose uptake through inhibition of the GLUT4 translocation, but not through alterations of the GLUT1 pathway.
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Affiliation(s)
- Hui-Chen Ku
- Department of Life Sciences, National Central University, 300 Jhongda Road, Jhongli, Taoyuan 320, Taiwan
| | - Yi-Wei Tsuei
- Taoyuan Armed Forces General Hospital, Longtan, Taoyuan 325, Taiwan
| | - Chung-Cheng Kao
- Taoyuan Armed Forces General Hospital, Longtan, Taoyuan 325, Taiwan
| | - Jueng-Tsueng Weng
- Department of Life Sciences, National Central University, 300 Jhongda Road, Jhongli, Taoyuan 320, Taiwan; Taoyuan Armed Forces General Hospital, Longtan, Taoyuan 325, Taiwan
| | - Li-Jane Shih
- Department of Life Sciences, National Central University, 300 Jhongda Road, Jhongli, Taoyuan 320, Taiwan; Taoyuan Armed Forces General Hospital, Longtan, Taoyuan 325, Taiwan
| | - Hsin-Huei Chang
- Department of Life Sciences, National Central University, 300 Jhongda Road, Jhongli, Taoyuan 320, Taiwan
| | - Chi-Wei Liu
- Department of Life Sciences, National Central University, 300 Jhongda Road, Jhongli, Taoyuan 320, Taiwan
| | | | | | - Yung-Hsi Kao
- Department of Life Sciences, National Central University, 300 Jhongda Road, Jhongli, Taoyuan 320, Taiwan.
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Prabhakar PK, Kumar A, Doble M. Combination therapy: a new strategy to manage diabetes and its complications. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2014; 21:123-130. [PMID: 24074610 DOI: 10.1016/j.phymed.2013.08.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/18/2013] [Accepted: 08/20/2013] [Indexed: 06/02/2023]
Abstract
Diabetes mellitus is the most common metabolic disorder. The major cause of mortality and morbidity here is due to the complications caused by increased glucose concentrations. All the available commercial antidiabetic drugs are associated with side effects. The combination therapy could be a new and highly effective therapeutic strategy to manage hyperglycemia. Combination of commercial drugs with phytochemicals may reduce the side effects caused by these synthetic drugs. Herbal products have been thought to be inherently safe, because of their natural origin and traditional use rather than based on systemic studies. New formulation and cocrystallisation strategies need to be adopted to match the bioavailability of the drug and the phytochemical. This review describes in detail, the observed synergy and mechanism of action between phytochemicals and synthetic drugs in effectively combating. The mode of action of combination differs significantly than that of the drugs alone; hence isolating a single component may lose its importance thereby simplifying the task of pharma industries.
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Affiliation(s)
- P K Prabhakar
- Lovely Faculty of Applied Medical Sciences, LPU, Phagwara, Punjab, India
| | - Anil Kumar
- Tata Chemicals Ltd., Innovation Centre, Pirangut, Pune 412108, India
| | - Mukesh Doble
- Department of Biotechnology, IIT Madras, Chennai, Tamilnadu, India.
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Wang CH, Wang CC, Huang HC, Wei YH. Mitochondrial dysfunction leads to impairment of insulin sensitivity and adiponectin secretion in adipocytes. FEBS J 2013; 280:1039-50. [PMID: 23253816 DOI: 10.1111/febs.12096] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 11/12/2012] [Accepted: 12/12/2012] [Indexed: 11/28/2022]
Abstract
Adipocytes play an integrative role in the regulation of energy metabolism and glucose homeostasis in the human body. Functional defects in adipocytes may cause systemic disturbance of glucose homeostasis. Recent studies revealed mitochondrial abnormalities in the adipose tissue of patients with type 2 diabetes. In addition, patients with mitochondrial diseases usually manifest systemic metabolic disorder. However, it is unclear how mitochondrial dysfunction in adipocytes affects the regulation of glucose homeostasis. In this study, we induced mitochondrial dysfunction and overproduction of reactive oxygen species (ROS) by addition of respiratory inhibitors oligomycin A and antimycin A and by knockdown of mitochondrial transcription factor A (mtTFA), respectively. We found an attenuation of the insulin response as indicated by lower glucose uptake and decreased phosphorylation of Akt upon insulin stimulation of adipocytes with mitochondrial dysfunction. Furthermore, the expression of glucose transporter 4 (Glut4) and secretion of adiponectin were decreased in adipocytes with increased ROS generated by defective mitochondria. Moreover, the severity of insulin insensitivity was correlated with the extent of mitochondrial dysfunction. These results suggest that higher intracellular ROS levels elicited by mitochondrial dysfunction resulted in impairment of the function of adipocytes in the maintenance of glucose homeostasis through attenuation of insulin signaling, downregulation of Glut4 expression, and decrease in adiponectin secretion. Our findings substantiate the important role of mitochondria in the regulation of glucose homeostasis in adipocytes and also provide a molecular basis for the explanation of the manifestation of diabetes mellitus or insulin insensitivity in a portion of patients with mitochondrial diseases such as MELAS or MERRF syndrome.
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Affiliation(s)
- Chih-Hao Wang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
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Harris VM, Bendre SV, Gonzalez De Los Santos F, Fite A, El-Yaman El-Dandachli A, Kurenbekova L, Abou-Samra AB, Buggs-Saxton C. GnRH increases glucose transporter-1 expression and stimulates glucose uptake in the gonadotroph. J Endocrinol 2012; 212:139-47. [PMID: 22107955 DOI: 10.1530/joe-11-0359] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
GnRH is the main regulator of the hypothalamic-pituitary-gonadal (H-P-G) axis. GnRH stimulates the pituitary gonadotroph to synthesize and secrete gonadotrophins (LH and FSH), and this effect of GnRH is dependent on the availability of glucose and other nutrients. Little is known about whether GnRH regulates glucose metabolism in the gonadotroph. This study examined the regulation of glucose transporters (Gluts) by GnRH in the LβT2 gonadotroph cell line. Using real-time PCR analysis, the expression of Glut1, -2, -4, and -8 was detected, but Glut1 mRNA expression level was more abundant than the mRNA expression levels of Glut2, -4, and -8. After the treatment of LβT2 cells with GnRH, Glut1 mRNA expression was markedly induced, but there was no GnRH-induction of Glut2, -4, or -8 mRNA expression in LβT2 cells. The effect of GnRH on Glut1 mRNA expression is partly mediated by ERK activation. GnRH increased GLUT1 protein and stimulated GLUT1 translocation to the cell surface of LβT2 cells. Glucose uptake assays were performed in LβT2 cells and showed that GnRH stimulates glucose uptake in the gonadotroph. Finally, exogenous treatment of mice with GnRH increased the expression of Glut1 but not the expression of Glut2, -4, or -8 in the pituitary. Therefore, regulation of glucose metabolism by GnRH via changes in Gluts expression and subcellular location in the pituitary gonadotroph reveals a novel response of the gonadotroph to GnRH.
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Affiliation(s)
- Valerie M Harris
- Division of Endocrinology, Department of Pediatrics, Children's Hospital of Michigan, Wayne State University School of Medicine, 3901 Beaubien Boulevard, 421 E. Canfield, Detroit, Michigan 48201-2119, USA
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Synergistic induction of interleukin-6 expression by endothelin-1 and cyclic AMP in adipocytes. Int J Obes (Lond) 2012; 37:197-203. [PMID: 22290536 DOI: 10.1038/ijo.2012.11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND We have demonstrated previously that endothelin-1 (ET-1) may stimulate interleukin-6 (IL-6) release from 3T3-L1 adipocytes. In this study, we further examined the combined effect of ET-1 and cyclic adenosine monophosphate (cAMP) on IL-6 release. METHODS IL-6 release was measured by enzyme-linked immuosorbent assay. Reverse transcriptase-PCR and real-time PCR analyses were used to determine cellular mRNA levels. A luciferase reporter driven by promoter (-1310/+198) of mouse IL-6 gene was transfected into 3T3-L1 adipocytes to monitor IL-6 transcription. RESULTS ET-1 and cAMP induced IL-6 release in a synergistic manner that can be attributed to their synergistic induction of IL-6 gene expression, as evidenced by IL-6 mRNA analysis and the IL-6 promoter reporter assay. Both ET(A) and ET(B) receptors seem to be involved. In addition, enhanced IL-6 promoter activity can be similarly induced by ET-1 and catecholamines (epinephrine and norepinephrine). The cooperative interaction between ET-1 and cAMP on IL-6 expression seems distinctive, as no other proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and IL-1β, are similarly affected. In fact, cAMP inhibited ET-1-stimulated TNF-α and IL-1β expressions in adipocytes. Furthermore, injection of mice with epinephrine and ET-1 induced a tremendously synergistic increase in serum IL-6 levels. Nevertheless, whereas cAMP induced IL-6 expression in RAW264.7 mouse macrophages, ET-1 had no effect on either the basal or the cAMP-induced IL-6 expression. CONCLUSION ET-1 and epinephrine may boost plasma IL-6 levels in mice in a synergistic manner, probably through their synergistic induction of IL-6 expression in adipocytes. SIGNIFICANCE This study should provide a new perspective for treating IL-6-related diseases, especially those accompanied with elevated ET-1 and catecholamine levels.
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Kao YS, Fong JC. A novel cross-talk between endothelin-1 and cyclic AMP signaling pathways in the regulation of GLUT1 transcription in 3T3-L1 adipocytes. Cell Signal 2011; 23:901-10. [PMID: 21262356 DOI: 10.1016/j.cellsig.2011.01.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 01/14/2011] [Indexed: 01/04/2023]
Abstract
We showed previously that chronic exposure to both endothelin-1 (ET-1) and cAMP resulted in a synergistic increase in Glut1 transcription in 3T3-L1 adipocytes via a protein kinase C (PKC)-dependent mechanism. In the present study, we further examined the molecular mechanism involved. Employing transient transfections with Glut1 promoter/enhancer -luciferase reporter and several dominant negative or constitutively active PKC mutants, we identified PKCε as the responsible PKC. Investigation with deletion and mutation mutants of the promoter/enhancer reporter suggested that Sp1, CREB and AP-1 responsive elements on enhancer 2 were involved. Furthermore, chromatin immunoprecipitation and co-immunoprecipitation analysis were applied to characterize the interactions between these transcription factors and their bindings to enhancer 2 in vivo. The results indicate that there are both negative and positive interactions between ET-1 and cAMP signaling pathways. On the one hand, cAMP inhibits ET-1 induced NF-κB activation required for ET-1-stimulated Glut1 transcription; on the other hand, cAMP, via sustained CREB phosphorylation, may activate AP-1 and cooperate with ET-1-activated PKCε to enhance Sp1 expression and consequently to generate a stable enhancer 2-bound Sp1/pCREB/AP-1 complex, which can strongly facilitate Glut1 transcription more than the additive effect of ET-1 and cAMP alone.
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Affiliation(s)
- Ying-Shiun Kao
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan, ROC
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Chai SP, Chang YN, Fong JC. Endothelin-1 stimulates interleukin-6 secretion from 3T3-L1 adipocytes. Biochim Biophys Acta Gen Subj 2008; 1790:213-8. [PMID: 19162127 DOI: 10.1016/j.bbagen.2008.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 12/14/2008] [Accepted: 12/18/2008] [Indexed: 11/24/2022]
Abstract
BACKGROUND Since both endothelin-1 (ET-1) and interleukin-6 (IL-6) may induce insulin resistance and adipose tissue is a major contributor of circulating IL-6, we examined the effects of ET-1 on IL-6 secretion from 3T3-L1 adipocytes. METHODS IL-6 release was measured by ELISA. RT-PCR and real-time PCR analyses were used to determine cellular IL-6 mRNA levels. A luciferase reporter driven by promoter (-1310/+198) of mouse IL-6 gene was transfected into 3T3-L1 adipocytes to monitor IL-6 transcription. RESULTS Treatment of adipocytes with ET-1 dose- and time-dependently increased IL-6 secretion. The stimulatory effect of ET-1 on IL-6 secretion was abolished by actinomycin D and ET-1 induced an increase in IL-6 mRNA levels. ET-1 was able to enhance the IL-6 promoter activity and its stimulatory effect was inhibited by GF109203X, U0126, salicylate, dominant negative CREB and mithramycin A. Thus it appears that ET-1 may stimulate IL-6 secretion mainly through an enhanced IL-6 transcription, by a mechanism involving both protein kinase C and p42/p44 mitogen-activated protein kinase, and probably downstream NF-kappaB, CREB and Sp1 transcription factors. GENERAL SIGNIFICANCE This study demonstrates that ET-1 is able to increase IL-6 secretion from adipocytes and raises the possibility that ET-1-induced insulin resistance may be mediated by IL-6.
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Affiliation(s)
- Shin-Pei Chai
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
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Kozakai T, Sakate M, Saida K. Regulation of endothelin-1 expression and function by nutrient stress in mouse colon epithelia. Scand J Gastroenterol 2008; 43:886-94. [PMID: 18584528 DOI: 10.1080/00365520701792372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The endothelin (ET) system is influenced by a variety of stress conditions in many tissues. However, the effects of nutrient stress conditions on ET expression and its function are not well understood in the intestinal tract, while ET-1 gene expression and peptide were found in the intestinal tract. The aim of this study was to investigate the effect of feeding and fasting on the expression of ET-1 and short-circuit current (Isc) induced by ET-1 in mouse colon. MATERIAL AND METHODS Mice were fed freely, fasted for 48 h, and re-fed after fasting, respectively. ET-1 mRNA levels and peptide concentrations were analyzed using real-time polymerase chain reaction (PCR) and sandwich ELISA, respectively. Isc of epithelial tissue was measured under short-circuit conditions using a Ussing chamber. RESULTS ET-1 mRNA expression and peptide concentrations in epithelial colonic tissue were significantly increased 48 h after fasting, and decreased within 2 h of re-feeding after a 48-h fast. Furthermore, the addition of ET-1 to the serosal but not the mucosal side increased Isc in colonic epithelia. An increase in Isc was caused by chloride ion (Cl(-)) secretion because Isc induced by ET-1 was blocked by bumetanide and Cl(- -) free conditions. In addition, an increase in Isc induced by ET-1 in colon excised from fasted mice was much lower than that obtained from free-fed mice. CONCLUSIONS Gene expression, peptide concentration, and the function of ET-1 in mouse colonic epithelia are regulated by nutrient stress.
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Affiliation(s)
- Takaharu Kozakai
- National Institute of Advanced Industrial Science and Technology (AIST), Institute for Biological Resources and Functions, Ibaraki, Japan
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Kao YS, Fong JC. Endothelin-1 induces glut1 transcription through enhanced interaction between Sp1 and NF-κB transcription factors. Cell Signal 2008; 20:771-8. [DOI: 10.1016/j.cellsig.2007.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 12/17/2007] [Indexed: 01/04/2023]
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Endothelin-1 induction of Glut1 transcription in 3T3-L1 adipocytes involves distinct PKCε- and p42/p44 MAPK-dependent pathways. Biochim Biophys Acta Gen Subj 2008; 1780:154-9. [DOI: 10.1016/j.bbagen.2007.11.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 11/11/2007] [Accepted: 11/27/2007] [Indexed: 01/04/2023]
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Nevzorova J, Evans BA, Bengtsson T, Summers RJ. Multiple signalling pathways involved in beta2-adrenoceptor-mediated glucose uptake in rat skeletal muscle cells. Br J Pharmacol 2006; 147:446-54. [PMID: 16415914 PMCID: PMC1616992 DOI: 10.1038/sj.bjp.0706626] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
1. Beta-adrenoceptor (AR) agonists increase 2-deoxy-[3H]-D-glucose uptake (GU) via beta2-AR in rat L6 cells. The beta-AR agonists, zinterol (beta2-AR) and (-)-isoprenaline, increased cAMP accumulation in a concentration-dependent manner (pEC50=9.1+/-0.02 and 7.8+/-0.02). Cholera toxin (% max increase 141.8+/-2.5) and the cAMP analogues, 8-bromo-cAMP (8Br-cAMP) and dibutyryl cAMP (dbcAMP), also increased GU (196.8+/-13.5 and 196.4+/-17.3%). 2. The adenylate cyclase inhibitor, 2',5'-dideoxyadenosine (50 microM), significantly reduced cAMP accumulation to zinterol (100 nM) (109.7+35.0 to 21.6+4.5 pmol well(-1)), or forskolin (10 microM) (230.1+/-58.0 to 107.2+/-26.3 pmol well(-1)), and partially inhibited zinterol-stimulated GU (217+/-26.3 to 176.1+/-20.4%). The protein kinase A (PKA) inhibitor, 4-cyano-3-methylisoquinoline (100 nM), did not inhibit zinterol-stimulated GU. The PDE4 inhibitor, rolipram (10 microM), increased cAMP accumulation to zinterol or forskolin, and sensitised the GU response to zinterol, indicating a stimulatory role of cAMP in GU. 3. cAMP accumulation studies indicated that the beta2-AR was desensitised by prolonged stimulation with zinterol, but not forskolin, whereas GU responses to zinterol increased with time, suggesting that receptor desensitisation may be involved in GU. Receptor desensitisation was not reversed by inhibition of PKA or Gi. 4. PTX pretreatment (100 ng ml(-1)) inhibited insulin or zinterol-stimulated but not 8Br-cAMP or dbcAMP-stimulated GU. The PI3K inhibitor, LY294002 (1 microM), inhibited insulin- (174.9+/-5.9 to 142.7+/-2.7%) and zinterol- (166.9+/-7.6 to 141.1+/-8.1%) but not 8 Br-cAMP-stimulated GU. In contrast to insulin, zinterol did not cause phosphorylation of Akt. 5. The results suggest that GU in L6 cells involves three mechanisms: (1) an insulin-dependent pathway involving PI3K, (2) a beta2-AR-mediated pathway involving both cAMP and PI3K, and (3) a receptor-independent pathway suggested by cAMP analogues that increase GU independently of PI3K. PKA appears to negatively regulate beta2-AR-mediated GU.
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Affiliation(s)
- Julia Nevzorova
- Department of Pharmacology, PO Box 13E, Monash University, Victoria 3800, Australia
| | - Bronwyn A Evans
- Department of Pharmacology, PO Box 13E, Monash University, Victoria 3800, Australia
| | - Tore Bengtsson
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Roger J Summers
- Department of Pharmacology, PO Box 13E, Monash University, Victoria 3800, Australia
- Author for correspondence:
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Chiou GY, Fong JC. Synergistic effect of prostaglandin F2alpha and cyclic AMP on glucose transport in 3T3-L1 adipocytes. J Cell Biochem 2005; 94:627-34. [PMID: 15547951 DOI: 10.1002/jcb.20338] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The combined effect of prostaglandin F2alpha (PGF2alpha) and cAMP on glucose transport in 3T3-L1 adipocytes was examined. In cells pretreated with PGF2alpha and 8-bromo cAMP for 8 h, a synergy between these two agents on glucose uptake was found. Insulin-stimulated glucose transport, on the other hand, was only slightly affected. The synergistic effect of these two agents was suppressed in the presence of cycloheximide and actinomycin D. In concord, immunoblot and Northern blot analyses revealed that GLUT1 protein and mRNA levels were both increased in cells pretreated with both PGF2alpha and 8-bromo cAMP, greater than the additive effect of each agent alone. The synergistic action of PGF2alpha with 8-bromo cAMP to enhance glucose transport was inhibited by GF109203X, a selective protein kinase C (PKC) inhibitor. In addition, in cells depleted of diacylglycerol-sensitive PKC by prolonged treatment with 4beta-phorbol 12beta-myristate 13alpha-acetate, a PKC activator, the synergistic effects of PGF2alpha and 8-bromo cAMP on glucose transport and GLUT1 mRNA accumulation were both abolished. Taken together, these results indicate that PGF2alpha may act with cAMP in a synergistic way to increase glucose transport, probably through enhanced GLUT1 expression by a PKC-dependent mechanism.
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Affiliation(s)
- Guang-Yuh Chiou
- Institute of Biochemistry, National Yang-Ming University, Taipei, Taiwan, Republic of China
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