Telmisartan attenuates obesity-induced insulin resistance via suppression of AMPK mediated ER stress

Biochemical and Biophysical Research Communications xxx (xxxx) xxx

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Telmisartan attenuates obesity-induced insulin resistance via suppression of AMPK mediated ER stress Ya Huang a, b, Yanping Li b, Qinhui Liu b, Jinhang Zhang a, b, Zijing Zhang a, b, Tong Wu a, b, Qin Tang a, b, Cuiyuan Huang a, b, Rui Li a, b, Jian Zhou a, b, Guorong Zhang a, b, Yingnan Zhao a, b, Hui Huang a, b, Jinhan He*, a, b a b

Department of Pharmacy and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, China Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital, Sichuan University, China

a r t i c l e i n f o

a b s t r a c t

Article history: Received 1 December 2019 Accepted 20 December 2019 Available online xxx

Telmisartan is a known angiotensin II (Ang II) AT1 receptor blocker (ARB). While the beneficial effect of Telmisartan on glucose and lipid metabolism has been reported, the underlying molecular mechanism remained unclear. The endoplasmic reticulum (ER) stress is considered as one of important factors contributing to insulin resistance. In this study, we found that Telmisartan alleviated diet-induced obesity and insulin resistance, suppressed inflammation in adipose tissue, and alleviated hepatic steatosis. Furthermore, we showed that Telmisartan suppressed ER stress by activating AMP-activated protein kinase (AMPK) signaling pathway in vivo. In differentiated 3T3-L1 adipocytes, Telmisartan also improved palmitate acid (PA) induced ER stress. Compound C, an AMPK inhibitor, could abolish beneficial effect of Telmisartan on ER stress. Our data indicated Telmisartan improved obesity-induced insulin resistance through suppression of ER stress by activation of AMPK. These results provided the evidence that Telmisartan may have therapeutic potential for the treatment of obesity and type II diabetes. © 2020 Elsevier Inc. All rights reserved.

Keywords: Telmisartan Insulin resistance Obesity ER stress AMPK

1. Introduction Diet and lifestyle changes have led to prevalence of obesity. Obesity population is increasingly large at alarming rate [1]. Obesity-induced Insulin resistance is a major main hallmark of metabolic syndrome, which triggers the onset of type II diabetes mellitus and cardiovascular disease [2]. White adipose tissue (WAT) plays an essential role in maintaining metabolic homeostasis [3]. Dysfunction in WAT results in ER stress [4]. ER, a membranous network in the cell serves as a compartment for protein folding, assembly, modification and quality control [5]. ER stress leads to metabolic disturbances including insulin resistance, lipid accumulation and process to type II diabetes [6]. Accumulating studies indicates activation of AMPK is involved in the regulation of ER stress [7e9]. AMPK, a conserved sensor of cellular energy status, improves insulin sensitivity and

* Corresponding author. Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital of Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, 610041, China. E-mail address: [email protected] (J. He).

reduces the risk for obesity and type II diabetes (Kahn et al., 2005 [10]. Telmisartan is an Ang II AT1 receptor selective blocker, which has been used for treatment of hypertension and involves in cardiovascular regulation [11,12]. It was reported that Telmisartan improved glucose and lipid metabolism and induced fat redistribution in diet-induced obese mice [13]. In addition, Telmisartan could improve obesity, metabolic syndrome or glucose intolerance in hypertensive patients with obesity [14]. While, the underlying mechanism of Telmisartan in regulating obesity-induced insulin resistance remains unclear. High fat diet (HFD) is commonly used to induce obesity and insulin resistance. Excessive energy intake can pose challenges to elicit ER stress [15]. In this study, we used HFD-induced obese model in vivo and differentiated 3T3-L1 adipocyte cells in vitro to investigate the protective effect of Telmisartan on obesity-induced insulin resistance and ER stress. We found that Telmisartan protected mice from HFD-induced obesity, insulin resistance and chronic inflammation. In addition, the mice treated with Telmisartan showed an increased activation of AMPK, then further led to alleviation of ER stress. These results indicated that Telmisartan exerts positive influence on diet-induced obesity and insulin

https://doi.org/10.1016/j.bbrc.2019.12.111 0006-291X/© 2020 Elsevier Inc. All rights reserved.

Please cite this article as: Y. Huang et al., Telmisartan attenuates obesity-induced insulin resistance via suppression of AMPK mediated ER stress, Biochemical and Biophysical Research Communications, https://doi.org/10.1016/j.bbrc.2019.12.111

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resistance, and may have potential protective effect to treat type II diabetes in clinical practice. 2. Materials and methods 2.1. Animal model and treatments C57BL/6J male mice were housed in the Division of Laboratory Animal Resources, West China Hospital of Sichuan University in a specific pathogen-free environment with a 12h-light-dark cycle, 24
C-indoor temperature, 55 ± 15% relative humidity. Mice have free access to food and water. For obesity model, eight-week-old mice were fed with HFD (60% kcal fat, Research Diet, D12492) for 12 weeks. Telmisartan (Meilunbio, 144701-48-4, >99% purity) (Fig. S1A) was mixed with powdered HFD at 0.003% (w/w) [13]. Blood, Liver, epididymal white adipose tissues (eWAT), inguinal white adipose tissues (iWAT) and Brown adipose tissues (BAT) were collected and stored in 80
C. All animal experiments in this research were carried out in accordance with the relevant regulations of the Sichuan University Laboratory Animal Ethics committee.

with DMEM containing 10% fetal bovine serum, 5 mg/ml insulin (Nova, China), 0.5 mM 3-isobutyl1-methyl-xanthine (Santa Cruz, USA), and 0.25 mM dexamethasone (Sigma-Aldrich, Saint Louis, MO, USA) for 2 days. Next, cells were cultured for an additional 2 days in maturation medium (DMEM containing 10% FBS and 5 mg/mL insulin) and then maintained in DMEM medium containing 10% FBS for 5 days. Differentiated 3T3L1 adipocytes were treated with compound C (Merck, 866405-64-3, >95% purity) (Fig. S1B). 2.7. Western blotting analysis The total protein was extracted by loading buffer containing 62 mM Tris-HCL, pH6.8, 2%SDS, 0.1 mM Na3VO4, and 50 mM NaF. Equal content protein was separated by SDS-PAGE. The protein was transferred to nitrocellulose membranes. After blocking with 0.5% casein (Sigma, New Zealand) for 1 h, the membrane was incubated by primary antibodies at 4
C overnight and incubated with secondary antibodies for 1 h at room temperature. The signal was detected and recorded using a LI-COR System (Lincoln, NE). Quantitative determination of band intensity was conducted using Image Studio (Li-COR). Primary antibodies and secondary antibodies were listed in Supplementary Table 1.

2.2. Glucose tolerance test (GTT) and insulin tolerance test (ITT) 2.8. Total RNA extraction and real-time PCR analysis For GTT, mice were injected with glucose (2 g/kg) intraperitoneally. For ITT, mice were injected with insulin (0.75 U/kg) intraperitoneally. Blood was collected at 0 min, 15 min, 30 min, 60 min, 90 min, and 120 min, and was measured by glucometer (Roche, Basel, Switzerland). 2.3. Hepatic lipid analysis Liver tissues (50 mg) were homogenized with 500 ml PBS. The homogenates were added to 7.5 ml chloroform/methanol (2:1) and 1 ml ddH2O and shock vigorously and then centrifuged at 3000 rpm for 10 min. The lower phase was transferred to a new tube. The lower phase containing lipids was evaporated. The dried pellet was resuspended in 1% Triton X-100 in ethanol and analyzed using total cholesterol and triglycerides kits (Biosino, Beijing, China).

The total RNA of the tissues was extracted with TRIzol reagent (Life technologies). The cDNA synthesized from RNA by reverse transcription kit (RR037A; TaKaRa, Kyoto, Japan) and cDNA samples were quantified by CFX96 Real-time RT-PCR System (Hercules, CA) with SYBR Green PCR Master Mix (Takara, Tokyo, Japan). The Primers are listed in Supplementary Table 2. 2.9. Statistical analysis Date was shown as mean ± SEM of at least three samples at each group. Student’s t-test or one way ANOVA Turkey’s test was used for data analysis. P < 0.05 was considered statistically significant. 3. Results 3.1. Telmisartan protects mice from HFD diet-induced obesity

2.4. Histological staining Liver and adipose tissues were fixed in 10% formalin and embedded in paraffin, sectioned at 5 mm, and stained with hematoxylin and eosin (H&E). Frozen sections (6 mm) were used for Oil Red O staining. Images were captured by a microscope (Nikon, Tokyo, Japan). 2.5. Immunofluorescence staining The paraffin-embedded eWAT sections were incubated with primary antibody anti-F4/80 (Abcam, USA) overnight at 4
C. Then, the sample was incubated FITC-conjugated secondary Antibody (Abcam, USA) for 1 h and stained DAPI. Images were captured by a microscope (Nikon, Tokyo, Japan). 2.6. Cell culture and treatments The mouse embryonic fibroblast lines 3T3L1 pre-adipocyte (ATCC, Rockville, MD) were cultured with high glucose Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum and antibiotics (50 mg/ml penicillin, 100 mg/ml neomycin and 50 mg/ml streptomycin) and incubated at 37
C with 5% CO2. Preadipocytes were cultured in differentiation induction medium

To assess the role of Telmisartan in obesity, C57BL/6J mice were fed with Telmisartan supplemented in HFD at 0.003% (w/w). Based on daily food intake and body weight, 0.003% (w/w) was approximately equivalent to 3 mg/kg [13]. Mice fed with Telmisartan gained less body weight than controls (Fig. 1A). To understand the decreased body weight seen in Telmisartan-treated mice, we weighed different fat pads and liver tissues. The results showed that the ratio of the weight of fat pads to bodyweight was decreased significantly (Fig. 1B). Similarly, liver weight was less in mice treated with Telmisartan than controls (Fig. S2A). H&E staining indicated that adipocytes of eWAT, iWAT and BAT were smaller and less lipid accumulation in liver from mice treated with Telmisartan compared with controls (Fig. 2C and Fig. S2B). The quantification of adipocyte size further supported the result of histological analysis (Fig. 2B). Therefore, treatment of Telmisartan protects mice from diet-induced obesity. 3.2. Telmisartan improves obesity induced insulin resistance To determine whether Telmisartan improves obesity-induced insulin resistance, we conducted GTT or ITT. As shown in Fig. 2AeB, GTT and ITT were significantly improved in Telmisartan treated mice. We further assessed the insulin signaling activity in

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Fig. 1. Telmisartan protects mice from HFD -induced obesity. (A) Representative gross pictures (top) and body weight curve (bottom) of C57BL/6J mice fed with or without Telmisartan under high fat diet (HFD) for 12 weeks (n ¼ 10). (B) Representative pictures (top) and the ratio of fat pads to bodyweight (bottom) (eWAT, iWAT and BAT). (C) The representative H&E-staining images of eWAT, iWAT and BAT. (C) Frequency of adipocyte size of eWAT and iWAT from mice fed with or without Telmisartan under HFD. All data are presented as mean ± SEM. *p < 0.05, **p < 0.01.

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Fig. 2. Telmisartan improves obesity-induced insulin resistance. The analysis of (A) glucose tolerance test (GTT) and (B) insulin tolerance test (ITT) in mice fed with or without Telmisartan under HFD. (C) Western blotting analysis of phosphorylated AKT and AKT levels in eWAT, liver and skeletal muscle. Under HFD, mice fed with or without telmisartan were injected with insulin (1U/kg) or saline through portal vein. (D) Western blotting analysis of phosphorylated AKT and AKT levels in differentiated 3T3-L1 adipocytes. Differentiated 3T3-L1 adipocytes were exposure to Telmisartan (10 nM) and 200 mM palmitate acid (PA) for 24 h, followed by 100 nM insulin for 30 min. All data are presented as mean ± SEM. *p < 0.05, **p < 0.01.

various tissues including adipose tissue, liver and muscle in vehicle and Telmisartan treated mice after acute injection of insulin. We found that insulin induced phosphorylation of AKT was greatly improved in adipose tissue from Telmisartan treated mice (Fig. 2C and Fig. S3A). Whereas, insulin induced phosphorylation of AKT had no apparent differences in liver and skeletal muscle between two groups (Fig. 2C and Fig. S3A). In differentiated 3T3-L1 adipocytes, PA impaired the insulin signaling activity as previously reported [16]. However, such impairment was improved by Telmisartan treatment (Fig. 2D and Fig. S3B).

protein levels compared with control mice (Fig. 3B). In addition, we found Telmisartan activated AMPK in a dose-dependent way in 3T3-L1 adipocytes (Fig. 3C). To understand whether AMPK activation by Telmisartan could be responsible for the relieved ER stress, we tested whether AMPK inhibitor, compound C, could abolish the effect on ER stress of Telmisartan. In differentiated 3T3-L1 adipocytes, Telmisartan alleviated PA induced ER stress. However, inhibition of AMPK pathway greatly abolished Telmisartan’s effect on ER stress (Fig. 3D). These results indicated that Telmisartan suppresses ER stress in vivo and vitro through AMPK activation compared to controls.

3.3. Telmisartan alleviates ER stress via activating AMPK pathway It has been found that ER stress is activated during the insulin resistance [5]. Telmisartan deregulated the mRNA expression of ER stress relative genes, such as X-box binding protein-1 (Xbp1s), 78kD glucose-regulated/binding immunoglobulin protein (Grp78), C/ EBP homologous protein (Chop) and activating transcription factor 6 (Atf6) (Fig. 3A). AMPK activation improves insulin sensitivity and reduces the risk for obesity [10]. AMPK also regulates ER stress [7e9]. We found that Telmisartan increased phosphorylated AMPK

3.4. Telmisartan suppresses inflammation and increases the lipolytic activity in adipose tissue Low-grade inflammation in adipose tissue is a well-known cause of insulin resistance [2]. So, we examined the mRNA expression of pro-inflammatory gene including tumour necrosis factor a (Tnf-a), monocyte chemoattractant protein-1 (Mcp-1) and interleukin 18 (Il-18). We found Telmisartan significantly decreased the expression of Tnf-a, Mcp-1and Il-18 compared to controls

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Fig. 3. Telmisartan alleviates ER stress via activating AMPK pathway. (A) Real-time PCR analysis of mRNA levels of ER stress relative genes in eWAT from mice fed with or without Telmisartan under HFD (n ¼ 9e10). Western blotting analysis of AMPK and phosphorylated AMPK levels in eWAT from mice fed with or without Telmisartan under HFD (B) or in differentiated 3T3L1 adipocytes treated with different concentrations of Telmisartan(C). (D) Real-time PCR analysis of mRNA expression of ER stress relative genes in differentiated 3T3-L1 adipocyte treated with 200 mM palmitate acid (PA), in the presence or absence of Telmisartan (10 nM). To inhibit AMPK signaling, differentiated 3T3-L1 adipocytes were pretreated with 40 mM Compound C for 1 h. All data are presented as mean ± SEM. *p < 0.05, **p < 0.01.

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(Fig. 4A). Consistent with suppressed inflammation, Telmisartan decreased the infiltration of macrophages as indicated by the lower expression of macrophage markers such as F4/80, Cd11b and Cd11c (Fig. 4B). Consistent with the expression of mRNA, immunofluorescence staining revealed macrophage marker F4/80 levels was lower in eWAT from mice treated with Telmisartan (Fig. 4C). Thus, these findings indicated that Telmisartan improves visceral adipose

inflammation. Lipolysis is a process of triglyceride breakdown that liberates glycerol and free fatty acid [17]. Accumulation of excess circulating free fatty acid (FFA) leads to insulin resistance [18]. We firstly examined the lipolytic activity in eWAT. Telmisartan markedly upregulated the expression of adipose triglyceride lipase (ATGL), a key lipolytic lipase, and phosphorylation of HSL and perilipin1

Fig. 4. Telmisartan suppresses inflammation in adipose tissue. Real-time analysis of (A) pro-inflammatory relative genes mRNA levels and (B) macrophage markers in eWAT from mice fed with or without Telmisartan under HFD (n ¼ 9). (C) The immunofluorescent staining analysis of F4/80 levels in eWAT from mice fed with or without Telmisartan under HFD (n ¼ 4). All data are presented as mean ± SEM. *p < 0.05, **p < 0.01.

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compared to controls (Fig. S4A). Similarly, lipolytic activity was activated by Telmisartan in iWAT (Fig. S4B). However, the serum FFA level had no apparent difference in both groups (Fig. S4C). Thus, these findings suggested that Telmisartan promotes lipolytic activity in adipose tissues but does not decrease circulating FFA level.

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Funding This work was supported by the National Natural Science Foundation of China (81930020, 81603035 and 81870599), China Postdoctoral Fellowship (2017M612981), Young Scientist Fellowship of Sichuan University (2017SCU11026), and Postdoctoral Fellowship of Sichuan University (2017SCU12036).

4. Discussion Author contributions statement Recent years, accumulating studies have suggested that Telmisartan, a drug used to treat high blood pressure in clinical practice, has positive effect on obesity and obesity-induced insulin resistance in rodent models [19e22]. Clinical studies also showed that Telmisartan could improve insulin resistance in hypertensive patients with obesity [14]. After short-term administration of Telmisartan, insulin resistance was also significantly improved in hypertensive patients with metabolic syndrome [23]. While Telmisartan (160 mg/d) did not show significant effect on insulin sensitivity in a population of normotensive, nondiabetic patients with clinical evidence of IR [24]. The effect of Telmisartan on insulin sensitivity remained controversial and the molecular mechanism how Telmisartan regulated glucose and lipid metabolism remained poorly studied. To better clarify the mechanism, we used HFDinduced obesity model and found that Telmisartan reduced the gained body weight induced by HFD. Telmisartan significantly decreased the adipose tissue mass after HFD feeding. Metabolic studies found that insulin resistance was significantly improved in Telmisartan treated mice compared to control group. Consistently, insulin induced the phosphorylation of AKT was higher in Telmisartan treated mice. ER is an essential organelle that plays an important role in regulation metabolic diseases [25]. ER stress is close to be associated with obesity-induced insulin resistance. ER stress contributes to accumulation of misfolding or unfolding protein and activation of UPR in most cells, which is characterized by activation of three canonical ER stress sensors, the protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1a (IRE1a), and activating transcription factor 6 (ATF6) [26]. Glucose metabolism disordered and insulin resistance were induced by IRE1a/XBP-1 pathway in subclinical hypothyroidism [27]. Recent study indicated that Ang II leads to ER stress in adipose tissue and adipocytes [28]. Telmisartan is a blocker of Ang II AT1 receptor. So, we examined the ER stress relative genes expression in adipose tissues from mice treated with Telmisartan. We found Telmisartan downregulated ER stress related mRNA levels in vivo. Our in vitro study also showed that Telmisartan suppressed PA-induced ER stress. The AMP-activated protein kinase (AMPK) is a conserved sensor of cellular energy status, which involves in energy metabolism regulation [10]. AMPK may improve insulin sensitivity and reduce the risk for obesity and type II diabetes through multiple pathways [10]. Thyroid hormones could decrease ceramide induced ER stress via AMPK activation [29]. In addition, Dong et al. found that reduction of AMPKa2 increases ER stress [7]. In this study, we also found Telmisartan activated AMPK pathway, which is consistent with previous study [30]. Telmisartan also relieved ER stress in adipose tissue. In differentiated 3T3-L1 adipocytes, Telmisartan could alleviate PA induced ER stress and this alleviation could be abolished by compound C, an inhibitor of AMPK [31]. During feeding, WAT stored excess of calories as fat. While, during fasting, FFA was released to supply for body by hydrolyzing the triglyceride stored in WAT [32]. During the progress of obesity, the lipolytic capacity was impaired [33]. We found that Telmisartan could preserve the lipolytic activity by upregulating the expression of ATGL and the phosphorylation of HSL and Perilipin1.

Y.H. designed and performed experiments and wrote the manuscript. Y. L., Q. L., J. Z., Z.Z., T. W., Q. T. and C. H. contributed to the discussion and review of the manuscript. R. L., J. Z., G. Z., Y. Z. and H.H. helped with experiments. J. H. obtained funding, designed experiments, and wrote the manuscript. Y. H. and J.H. are the guarantors of this work and, as such, had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Declaration of competing interest There are no conflicts to declare. Acknowledgements This work was supported by the National Natural Science Foundation of China (81930020, 81873662 and 81870599), Research funding from Sichuan Province (2018SZ0158), China Postdoctoral Fellowship (2017M612981), Young Scientist Fellowship of Sichuan University (2017SCU11026), and Postdoctoral Fellowship of Sichuan University (2017SCU12036). Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.bbrc.2019.12.111. References [1] J.S. Flier, Obesity wars: molecular progress confronts an expanding epidemic, Cell 116 (2004) 337e350, https://doi.org/10.1016/s0092-8674(03)01081-x. [2] A.M. Johnson, J.M. Olefsky, The origins and drivers of insulin resistance, Cell 152 (2013) 673e684, https://doi.org/10.1016/j.cell.2013.01.041. [3] C. Zou, J. Shao, Role of adipocytokines in obesity-associated insulin resistance, J. Nutr. Biochem. 19 (2008) 277e286, https://doi.org/10.1016/ j.jnutbio.2007.06.006. [4] W. Zhu, X. Niu, M. Wang, Z. Li, H.K. Jiang, C. Li, S.J. Caton, Y. Bai, Endoplasmic reticulum stress may be involved in insulin resistance and lipid metabolism disorders of the white adipose tissues induced by high-fat diet containing industrial trans-fatty acids, Diabetes, Metab. Syndrome Obes. Targets Ther. 12 (2019) 1625e1638, https://doi.org/10.2147/dmso.s218336. [5] U. Ozcan, Q. Cao, E. Yilmaz, A.H. Lee, N.N. Iwakoshi, E. Ozdelen, G. Tuncman, C. Gorgun, L.H. Glimcher, G.S. Hotamisligil, Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes, Science (N.Y.) 306 (2004) 457e461, https://doi.org/10.1126/science.1103160. [6] L. Salvado, X. Palomer, E. Barroso, M. Vazquez-Carrera, Targeting endoplasmic reticulum stress in insulin resistance, Trends Endocrinol. Metab. 26 (2015) 438e448, https://doi.org/10.1016/j.tem.2015.05.007. [7] Y. Dong, M. Zhang, B. Liang, Z. Xie, Z. Zhao, S. Asfa, H.C. Choi, M.H. Zou, Reduction of AMP-activated protein kinase alpha2 increases endoplasmic reticulum stress and atherosclerosis in vivo, Circulation 121 (2010) 792e803, https://doi.org/10.1161/CIRCULATIONAHA.109.900928. [8] F. Gao, J. Chen, H. Zhu, A potential strategy for treating atherosclerosis: improving endothelial function via AMP-activated protein kinase, Science China, Life Sci. 61 (2018) 1024e1029, https://doi.org/10.1007/s11427-0179285-1. [9] G.R. Steinberg, J.D. Schertzer, AMPK promotes macrophage fatty acid oxidative metabolism to mitigate inflammation: implications for diabetes and cardiovascular disease, Immunol. Cell Biol. 92 (2014) 340e345, https://doi.org/ 10.1038/icb.2014.11. [10] B.B. Kahn, T. Alquier, D. Carling, D.G. Hardie, AMP-activated protein kinase: ancient energy gauge provides clues to modern understanding of metabolism, Cell Metabol. 1 (2005) 15e25, https://doi.org/10.1016/j.cmet.2004.12.003.

Please cite this article as: Y. Huang et al., Telmisartan attenuates obesity-induced insulin resistance via suppression of AMPK mediated ER stress, Biochemical and Biophysical Research Communications, https://doi.org/10.1016/j.bbrc.2019.12.111

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[11] V.I. Podzolkov, A.I. Tarzimanova, [Telmisartan in the treatment of hypertensive patients], Ter. Arkhiv 89 (2017) 110e113, https://doi.org/10.17116/terarkh2017896110-113. [12] T. Chen, J. Xing, Y. Liu, Effects of telmisartan on vascular endothelial function, inflammation and insulin resistance in patients with coronary heart disease and diabetes mellitus, Exp. Ther. Med. 15 (2018) 909e913, https://doi.org/ 10.3892/etm.2017.5451. [13] L. Li, Z. Luo, H. Yu, X. Feng, P. Wang, J. Chen, Y. Pu, Y. Zhao, H. He, J. Zhong, D. Liu, Z. Zhu, Telmisartan improves insulin resistance of skeletal muscle through peroxisome proliferator-activated receptor-delta activation, Diabetes 62 (2013) 762e774, https://doi.org/10.2337/db12-0570. [14] G.J. Choi, H.M. Kim, H. Kang, J. Kim, Effects of telmisartan on fat distribution: a meta-analysis of randomized controlled trials, Curr. Med. Res. Opin. 32 (2016) 1303e1309, https://doi.org/10.1185/03007995.2016.1171204. [15] E.S. Wires, K.A. Trychta, S. Back, A. Sulima, K.C. Rice, B.K. Harvey, High fat diet disrupts endoplasmic reticulum calcium homeostasis in the rat liver, J. Hepatol. 67 (2017) 1009e1017, https://doi.org/10.1016/j.jhep.2017.05.023. [16] M. Ishii, A. Maeda, S. Tani, M. Akagawa, Palmitate induces insulin resistance in human HepG2 hepatocytes by enhancing ubiquitination and proteasomal degradation of key insulin signaling molecules, Arch. Biochem. Biophys. 566 (2015) 26e35, https://doi.org/10.1016/j.abb.2014.12.009. [17] J. Kuang, Y. Zhang, Q. Liu, J. Shen, S. Pu, S. Cheng, L. Chen, H. Li, T. Wu, R. Li, Y. Li, M. Zou, Z. Zhang, W. Jiang, G. Xu, A. Qu, W. Xie, J. He, Fat-specific Sirt6 ablation sensitizes mice to high-fat diet-induced obesity and insulin resistance by inhibiting lipolysis, Diabetes 66 (2017) 1159e1171, https://doi.org/ 10.2337/db16-1225. [18] J. He, C. Xu, J. Kuang, Q. Liu, H. Jiang, L. Mo, B. Geng, G. Xu, Thiazolidinediones attenuate lipolysis and ameliorate dexamethasone-induced insulin resistance, Metab. Clin. Exp. 64 (2015) 826e836, https://doi.org/10.1016/ j.metabol.2015.02.005. [19] K. Araki, T. Masaki, I. Katsuragi, K. Tanaka, T. Kakuma, H. Yoshimatsu, Telmisartan prevents obesity and increases the expression of uncoupling protein 1 in diet-induced obese mice, Hypertension 48 (2006) 51e57, https://doi.org/ 10.1161/01.HYP.0000225402.69580.1d. € lting, E.E. Wing, K. Saar, N. Hübner, W.A. Banks, [20] F. Schuster, G. Huber, I. Sto W. Raasch, Telmisartan prevents diet-induced obesity and preserves leptin transport across the blood-brain barrier in high-fat diet-fed mice, Pflueg. Arch. Eur. J. Physiol. 470 (2018) 1673e1689, https://doi.org/10.1007/s00424-0182178-0. [21] K.C. Cheng, Y. Li, W.T. Chang, F.Y. Kuo, Z.C. Chen, J.T. Cheng, Telmisartan is effective to ameliorate metabolic syndrome in rat model - a preclinical report, Diabetes, Metab. Syndrome Obes. Targets Ther. 11 (2018) 901e911, https:// doi.org/10.2147/dmso.s187092. [22] Y. Wang, J. Xue, Y. Li, X. Zhou, S. Qiao, D. Han, Telmisartan protects against high glucose/high lipid-induced apoptosis and insulin secretion by reducing the oxidative and ER stress, Cell Biochem. Funct. 37 (2019) 161e168, https:// doi.org/10.1002/cbf.3383. [23] S. Kiyici, M. Guclu, F. Budak, D. Sigirli, E. Tuncel, Even short-term telmisartan treatment ameliorated insulin resistance but had No influence on serum

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

adiponectin and tumor necrosis factor-alpha levels in hypertensive patients with metabolic syndrome, Metab. Syndrome Relat. Disord. 17 (2019) 167e172, https://doi.org/10.1089/met.2018.0129. W. Hsueh, G. Davidai, R. Henry, S. Mudaliar, Telmisartan effects on insulin resistance in obese or overweight adults without diabetes or hypertension, J. Clin. Hypertens. 12 (2010) 746e752, https://doi.org/10.1111/j.17517176.2010.00335.x. Y.S. Oh, G.D. Bae, D.J. Baek, E.-Y. Park, H.-S. Jun, Fatty acid-induced lipotoxicity in pancreatic beta-cells during development of type 2 diabetes, Front. Endocrinol. 9 (2018), https://doi.org/10.3389/fendo.2018.00384. R. Villalobos-Labra, M. Subiabre, F. Toledo, F. Pardo, L. Sobrevia, Endoplasmic reticulum stress and development of insulin resistance in adipose, skeletal, liver, and foetoplacental tissue in diabesity, Mol. Asp. Med. 66 (2019) 49e61, https://doi.org/10.1016/j.mam.2018.11.001. C. Xu, L. Zhou, K. Wu, Y. Li, J. Xu, D. Jiang, L. Gao, Abnormal glucose metabolism and insulin resistance are induced via the IRE1a/XBP-1 pathway in subclinical hypothyroidism, Front. Endocrinol. 10 (2019), https://doi.org/10.3389/ fendo.2019.00303. K.R. Menikdiwela, L. Ramalingam, L. Allen, S. Scoggin, N.S. Kalupahana, N. Moustaid-Moussa, Angiotensin II increases endoplasmic reticulum stress in adipose tissue and adipocytes, Sci. Rep. 9 (2019) 8481, https://doi.org/ 10.1038/s41598-019-44834-8. N. Martinez-Sanchez, P. Seoane-Collazo, C. Contreras, L. Varela, J. Villarroya, E. Rial-Pensado, X. Buque, I. Aurrekoetxea, T.C. Delgado, R. Vazquez-Martinez, I. Gonzalez-Garcia, J. Roa, A.J. Whittle, B. Gomez-Santos, V. Velagapudi, Y.C.L. Tung, D.A. Morgan, P.J. Voshol, P.B. Martinez de Morentin, T. LopezGonzalez, L. Linares-Pose, F. Gonzalez, K. Chatterjee, T. Sobrino, G. MedinaGomez, R.J. Davis, N. Casals, M. Oresic, A.P. Coll, A. Vidal-Puig, J. Mittag, M. Tena-Sempere, M.M. Malagon, C. Dieguez, M.L. Martinez-Chantar, P. Aspichueta, K. Rahmouni, R. Nogueiras, G. Sabio, F. Villarroya, M. Lopez, Hypothalamic AMPK-ER stress-JNK1 Axis mediates the central actions of thyroid hormones on energy balance, Cell Metabol. 26 (2017) 212e229, https://doi.org/10.1016/j.cmet.2017.06.014, e212. A. Shiota, M. Shimabukuro, D. Fukuda, T. Soeki, H. Sato, E. Uematsu, Y. Hirata, H. Kurobe, N. Maeda, H. Sakaue, H. Masuzaki, I. Shimomura, M. Sata, Telmisartan ameliorates insulin sensitivity by activating the AMPK/SIRT1 pathway in skeletal muscle of obese db/db mice, Cardiovasc. Diabetol. 11 (2012) 139, https://doi.org/10.1186/1475-2840-11-139. Y. Dong, M. Zhang, S. Wang, B. Liang, Z. Zhao, C. Liu, M. Wu, H.C. Choi, T.J. Lyons, M.H. Zou, Activation of AMP-activated protein kinase inhibits oxidized LDL-triggered endoplasmic reticulum stress in vivo, Diabetes 59 (2010) 1386e1396, https://doi.org/10.2337/db09-1637. R. Zechner, F. Madeo, D. Kratky, Cytosolic lipolysis and lipophagy: two sides of the same coin, Nature reviews, Mol. Cell. Biol. 18 (2017) 671e684, https:// doi.org/10.1038/nrm.2017.76. D. Langin, A. Dicker, G. Tavernier, J. Hoffstedt, A. Mairal, M. Ryden, E. Arner, A. Sicard, C.M. Jenkins, N. Viguerie, V. van Harmelen, R.W. Gross, C. Holm, P. Arner, Adipocyte lipases and defect of lipolysis in human obesity, Diabetes 54 (2005) 3190e3197, https://doi.org/10.2337/diabetes.54.11.3190.

Please cite this article as: Y. Huang et al., Telmisartan attenuates obesity-induced insulin resistance via suppression of AMPK mediated ER stress, Biochemical and Biophysical Research Communications, https://doi.org/10.1016/j.bbrc.2019.12.111