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Yang YN, Zhang MQ, Yu FL, Han B, Bao MY, Yan-He, Li X, Zhang Y. Peroxisom proliferator-activated receptor-γ coactivator-1α in neurodegenerative disorders: A promising therapeutic target. Biochem Pharmacol 2023; 215:115717. [PMID: 37516277 DOI: 10.1016/j.bcp.2023.115717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/26/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Neurodegenerative disorders (NDDs) are characterized by progressive loss of selectively vulnerable neuronal populations and myelin sheath, leading to behavioral and cognitive dysfunction that adversely affect the quality of life. Identifying novel therapies that attenuate the progression of NDDs would be of significance. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a widely expressed transcriptional regulator, modulates the expression of genes engaged in mitochondrial biosynthesis, metabolic regulation, and oxidative stress (OS). Emerging evidences point to the strong connection between PGC-1α and NDDs, suggesting its positive impaction on the progression of NDDs. Therefore, it is urgent to gain a deeper and broader understanding between PGC-1α and NDDs. To this end, this review presents a comprehensive overview of PGC-1α, including its basic characteristics, the post-translational modulations, as well as the interacting transcription factors. Secondly, the pathogenesis of PGC-1α in various NDDs, such as Alzheimer's (AD), Parkinson's (PD), and Huntington's disease (HD) is briefly discussed. Additionally, this study summarizes the underlying mechanisms that PGC-1α is neuroprotective in NDDs via regulating neuroinflammation, OS, and mitochondrial dysfunction. Finally, we briefly outline the shortcomings of current NDDs drug therapy, and summarize the functions and potential applications of currently available PGC-1α modulators (activator or inhibitors). Generally, this review updates our insight of the important role of PGC-1α on the development of NDDs, and provides a promising therapeutic target/ drug for the treatment of NDDs.
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Affiliation(s)
- Ya-Na Yang
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Mao-Qing Zhang
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Feng-Lin Yu
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Bing Han
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Ming-Yue Bao
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Yan-He
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Xing Li
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Yuan Zhang
- Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry (Shaanxi Normal University), The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China.
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2
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Cho YK, Lee S, Lee J, Doh J, Park JH, Jung YS, Lee YH. Lipid remodeling of adipose tissue in metabolic health and disease. Exp Mol Med 2023; 55:1955-1973. [PMID: 37653032 PMCID: PMC10545718 DOI: 10.1038/s12276-023-01071-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/30/2023] [Accepted: 06/05/2023] [Indexed: 09/02/2023] Open
Abstract
Adipose tissue is a dynamic and metabolically active organ that plays a crucial role in energy homeostasis and endocrine function. Recent advancements in lipidomics techniques have enabled the study of the complex lipid composition of adipose tissue and its role in metabolic disorders such as obesity, diabetes, and cardiovascular disease. In addition, adipose tissue lipidomics has emerged as a powerful tool for understanding the molecular mechanisms underlying these disorders and identifying bioactive lipid mediators and potential therapeutic targets. This review aims to summarize recent lipidomics studies that investigated the dynamic remodeling of adipose tissue lipids in response to specific physiological changes, pharmacological interventions, and pathological conditions. We discuss the molecular mechanisms of lipid remodeling in adipose tissue and explore the recent identification of bioactive lipid mediators generated in adipose tissue that regulate adipocytes and systemic metabolism. We propose that manipulating lipid-mediator metabolism could serve as a therapeutic approach for preventing or treating obesity-related metabolic diseases.
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Affiliation(s)
- Yoon Keun Cho
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sumin Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jaewon Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Junsang Doh
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Institute of Engineering Research, Bio-MAX Institute, Soft Foundry Institute, Seoul National University, Seoul, Republic of Korea
| | - Joo-Hong Park
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Young-Suk Jung
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Yun-Hee Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea.
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3
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Cao T, Wang S, Qian L, Wu C, Huang T, Wang Y, Li Q, Wang J, Xia Y, Xu L, Wang L, Huang X. NPRA promotes fatty acid metabolism and proliferation of gastric cancer cells by binding to PPARα. Transl Oncol 2023; 35:101734. [PMID: 37418841 DOI: 10.1016/j.tranon.2023.101734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/26/2023] [Accepted: 06/22/2023] [Indexed: 07/09/2023] Open
Abstract
Among cancers, gastric cancer (GC) ranks third globally in morbidity and mortality, particularly in East Asia. Natriuretic peptide receptor A (NPRA), a receptor for guanylate cyclase, plays important roles in regulating water and sodium balance. Recent studies have suggested that NPRA is involved in tumorigenesis, but its role in GC development remains unclear. Herein, we showed that the expression level of NPRA was positively correlated with gastric tumor size and clinical stage. Patients with high NPRA expression had a lower five-year survival rate than those with low expression, and NPRA was identified as an independent predictor of GC prognosis. NPRA knockdown suppressed GC cell proliferation, migration and invasion. NPRA overexpression enhanced cell malignant behavior. Immunohistochemistry of collected tumor samples showed that tumors with high NPRA expression had higher peroxisome proliferator-activated receptor α (PPARα) levels. In vivo and in vitro studies showed that NPRA promotes fatty acid oxidation and tumor cell metastasis. Co-IP showed that NPRA binds to PPARα and prevents PPARα degradation. PPARα upregulation under NPRA protection activates arnitine palmitoyl transferase 1B (CPT1B) to promote fatty acid oxidation. In this study, new mechanisms by which NPRA promotes the development of GC and new regulatory mechanisms of PPARα were identified.
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Affiliation(s)
- Tingting Cao
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Song Wang
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Long Qian
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China; General Surgery Department, Wuhu Hospital of Traditional Chinese Medicine, Wuhu, Anhui, China
| | - Chengwei Wu
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Tao Huang
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Ye Wang
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Qian Li
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Jiawei Wang
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Yabin Xia
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Li Xu
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China
| | - Luman Wang
- Department of Immunology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xiaoxu Huang
- Department of Gastrointestinal Surgery, The First Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, No.2, Zheshan West Road, Wuhu, Anhui 241001, China.
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Inhibition of carnitine palmitoyltransferase 1A in hepatic stellate cells protects against fibrosis. J Hepatol 2022; 77:15-28. [PMID: 35167910 DOI: 10.1016/j.jhep.2022.02.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS The pathogenesis of liver fibrosis requires activation of hepatic stellate cells (HSCs); once activated, HSCs lose intracellular fatty acids but the role of fatty acid oxidation and carnitine palmitoyltransferase 1A (CPT1A) in this process remains largely unexplored. METHODS CPT1A was found in HSCs of patients with fibrosis. Pharmacological and genetic manipulation of CPT1A were performed in human HSC cell lines and primary HCSs. Finally, we induced fibrosis in mice lacking CPT1A specifically in HSCs. RESULTS Herein, we show that CPT1A expression is elevated in HSCs of patients with non-alcoholic steatohepatitis, showing a positive correlation with the fibrosis score. This was corroborated in rodents with fibrosis, as well as in primary human HSCs and LX-2 cells activated by transforming growth factor β1 (TGFβ1) and fetal bovine serum (FBS). Furthermore, both pharmacological and genetic silencing of CPT1A prevent TGFβ1- and FBS-induced HSC activation by reducing mitochondrial activity. The overexpression of CPT1A, induced by saturated fatty acids and reactive oxygen species, triggers mitochondrial activity and the expression of fibrogenic markers. Finally, mice lacking CPT1A specifically in HSCs are protected against fibrosis induced by a choline-deficient high-fat diet, a methionine- and choline-deficient diet, or treatment with carbon tetrachloride. CONCLUSIONS These results indicate that CPT1A plays a critical role in the activation of HSCs and is implicated in the development of liver fibrosis, making it a potentially actionable target for fibrosis treatment. LAY SUMMARY We show that the enzyme carnitine palmitoyltransferase 1A (CPT1A) is elevated in hepatic stellate cells (HSCs) in patients with fibrosis and mouse models of fibrosis, and that CPT1A induces the activation of these cells. Inhibition of CPT1A ameliorates fibrosis by preventing the activation of HSCs.
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5
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Kurchaba N, Charette JM, LeMoine CMR. Metabolic consequences of PGC-1α dysregulation in adult zebrafish muscle. Am J Physiol Regul Integr Comp Physiol 2022; 323:R319-R330. [PMID: 35670765 DOI: 10.1152/ajpregu.00188.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The peroxisome proliferator activated receptor gamma co-activator 1 alpha (PGC-1α) is central to the regulation of cellular and mitochondrial energy homeostasis in mammals, but its role in other vertebrates remains unclear. Indeed, previous work suggests extensive structural and functional divergence of PGC-1α in teleosts but this remains to be directly tested. Here, we describe the initial characterization of heterozygous PGC-1α mutant zebrafish lines created by CRISPR-Cas9 disruptions of an evolutionarily conserved regulatory region of the PGC-1α proximal promoter. Using qPCR, we confirmed the disruption of PGC-1α gene expression in striated muscle, leading to a simultaneous 4-fold increase in mixed skeletal muscle PGC-1α mRNA levels and an opposite 4-fold downregulation in cardiac muscle. In mixed skeletal muscle, most downstream effector genes were largely unaffected yet two mitochondrial lipid transporters, carnitine palmitoyltransferase 1 and 2, were strongly induced. Conversely, PGC-1α depression in cardiac muscle reduced the expression of several transcriptional regulators (estrogen related receptor alpha, nuclear respiratory factor 1 and PGC-1β) without altering metabolic gene expression. Using high resolution respirometry, we determined that white muscle exhibited increased lipid oxidative capacity with little difference in markers of mitochondrial abundance. Finally, using whole animal intermittent respirometry, we show that mutant fish exhibit a 2-fold higher basal metabolism than their wildtype counterparts. Altogether, this new model confirms a central but complex role for PGC-1α in mediating energy utilization in zebrafish and we propose its use as a valuable tool to explore the intricate regulatory pathways of energy homeostasis in a popular biomedical model.
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Affiliation(s)
| | - J Michael Charette
- Department of Chemistry, Brandon University, Brandon, MB, Canada.,Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB, Canada.,CancerCare Manitoba Research Institute, Winnipeg, MB, Canada
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6
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Sharma R, Sahoo B, Srivastava A, Tiwari S. Reduced insulin signaling and high glucagon in early insulin resistance impaired fast-fed regulation of renal gluconeogenesis via insulin receptor substrate. J Cell Biochem 2022; 123:1327-1339. [PMID: 35644013 DOI: 10.1002/jcb.30294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 05/11/2022] [Accepted: 05/18/2022] [Indexed: 11/08/2022]
Abstract
Gluconeogenesis is one of the key processes through which the kidney contributes to glucose homeostasis. Urinary exosomes (uE) have been used to study renal gene regulation noninvasively in humans and rodents. Recently, we demonstrated fast-fed regulation of phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme for gluconeogenesis, in human uE. The regulation was impaired in subjects with early insulin resistance. Here, we studied primary human proximal tubule cells (hPT) and human uE to elucidate a potential link between insulin resistance and fast-fed regulation of renal PEPCK. We demonstrate that fasted hPTs had higher PEPCK and insulin receptor substrate-2 (IRS2) mRNA and protein levels, relative to fed cells. The fast-fed regulation was, however, attenuated in insulin receptor knockdown (IRKO) hPTs. The IRKO was confirmed by the blunted insulin-induced response on PEPCK, PGC1α, p-IR, and p-AKT expression in IRKO cells. Exosomes secreted by the wild-type or IRKO hPT showed similar regulation to the respective hPT. Similarly, in human uE, the relative abundance of IRS-2 mRNA (to IRS1) was higher in the fasted state relative to the fed condition. However, the fast-fed difference was absent in subjects with early insulin resistance. These subjects had higher circulating glucagon levels relative to subjects with optimal insulin sensitivity. Furthermore, in hPT cells, glucagon significantly induced PEPCK and IRS2 gene, and gluconeogenesis. IR knockdown in hPT cells further increased the gene expression levels. Together the data suggest that reduced insulin sensitivity and high glucagon in early insulin resistance may impair renal gluconeogenesis via IRS2 regulation.
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Affiliation(s)
- Rajni Sharma
- Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Biswajit Sahoo
- Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Aneesh Srivastava
- Department of Urology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Swasti Tiwari
- Department of Molecular Medicine & Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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7
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Wu G, Dai Y, Yan Y, Zheng X, Zhang H, Li H, Chen W. The lactate receptor GPR81 mediates hepatic lipid metabolism and the therapeutic effect of metformin on experimental NAFLDs. Eur J Pharmacol 2022; 924:174959. [PMID: 35430208 DOI: 10.1016/j.ejphar.2022.174959] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 01/06/2023]
Abstract
The lactate receptor G protein-coupled receptor 81 (GPR81) has been recently implicated in lipolysis in adipose tissue. In this study, we accidently discovered the role of GPR81 in hepatic lipid metabolism. Data clearly showed that hepatic GPR81 was markedly up-regulated in fasted mice, whereas it was severely down-regulated in obese mice. Genetic deficiency of GPR81 impaired ketogenic response, enhanced hepatic lipid accumulation, and exacerbated hepatosteatosis under acute fasting conditions. Mechanically, we demonstrated that hepatic GPR81 might function as a modulator of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), activate the downsream transcription of liver carnitine o-palmitoyltransferase 1(L-CPT1), and thereby control the influx of fatty acids into mitochondria for β-oxidation. Importantly, metformin improved experimental nonalcoholic fatty liver disease (NAFLDs) in a GPR81-dependent manner. Collectively, GPR81 was critical for hepatic lipid homeostasis and activation of hepatic GPR81 might represent a promising strategy for the treatment of obesity and its associated metabolic disorders.
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Affiliation(s)
- Guanglu Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Yufeng Dai
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Yongheng Yan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Xu Zheng
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Haitao Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China.
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, China
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8
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Intestinal farnesoid X receptor signaling controls hepatic fatty acid oxidation. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159089. [PMID: 34856412 PMCID: PMC8864892 DOI: 10.1016/j.bbalip.2021.159089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 02/03/2023]
Abstract
In addition to maintaining bile acid, cholesterol and glucose homeostasis, farnesoid X receptor (FXR) also regulates fatty acid β-oxidation (FAO). To explore the different roles of hepatic and intestinal FXR in liver FAO, FAO-associated metabolites, including acylcarnitines and fatty acids, and FXR target gene mRNAs were profiled using an integrated metabolomic and transcriptomic analysis in control (Fxrfl/fl), liver-specific Fxr-null (FxrΔHep) and intestine-specific Fxr-null (FxrΔIE) mice, treated either with the FXR agonist obeticholic acid (OCA) or vehicle (VEH). Activation of FXR by OCA treatment significantly increased fatty acyl-CoA hydrolysis (Acot1) and decreased FAO-associated mRNAs in Fxrfl/fl mice, resulting in reduced levels of total acylcarnitines and relative accumulation of long/medium chain acylcarnitines and fatty acids in liver. FxrΔHep mice responded to OCA treatment in a manner similar to Fxrfl/fl mice while FxrΔIE mice responded differently, thus illustrating that intestinal FXR plays a critical role in the regulation of hepatic FAO. A significant negative-correlation between intestinal FXR-FGF15 and hepatic CREB-PGC1A pathways was observed after both VEH and OCA treatment, suggesting that OCA-induced activation of the intestinal FXR-FGF15 axis downregulates hepatic PGC1α signaling via inactivation of hepatic CREB, thus repressing FAO. This mechanism was confirmed in experiments based on human recombinant FGF19 treatment and intestinal Fgf15-null mice. This study revealed an important role for the intestinal FXR-FGF15 pathway in hepatic FAO repression.
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9
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González-Romero F, Mestre D, Aurrekoetxea I, O'Rourke CJ, Andersen JB, Woodhoo A, Tamayo-Caro M, Varela-Rey M, Palomo-Irigoyen M, Gómez-Santos B, de Urturi DS, Núñez-García M, García-Rodríguez JL, Fernández-Ares L, Buqué X, Iglesias-Ara A, Bernales I, De Juan VG, Delgado TC, Goikoetxea-Usandizaga N, Lee R, Bhanot S, Delgado I, Perugorria MJ, Errazti G, Mosteiro L, Gaztambide S, Martinez de la Piscina I, Iruzubieta P, Crespo J, Banales JM, Martínez-Chantar ML, Castaño L, Zubiaga AM, Aspichueta P. E2F1 and E2F2-Mediated Repression of CPT2 Establishes a Lipid-Rich Tumor-Promoting Environment. Cancer Res 2021; 81:2874-2887. [PMID: 33771899 DOI: 10.1158/0008-5472.can-20-2052] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/15/2020] [Accepted: 03/24/2021] [Indexed: 11/16/2022]
Abstract
Lipid metabolism rearrangements in nonalcoholic fatty liver disease (NAFLD) contribute to disease progression. NAFLD has emerged as a major risk for hepatocellular carcinoma (HCC), where metabolic reprogramming is a hallmark. Identification of metabolic drivers might reveal therapeutic targets to improve HCC treatment. Here, we investigated the contribution of transcription factors E2F1 and E2F2 to NAFLD-related HCC and their involvement in metabolic rewiring during disease progression. In mice receiving a high-fat diet (HFD) and diethylnitrosamine (DEN) administration, E2f1 and E2f2 expressions were increased in NAFLD-related HCC. In human NAFLD, E2F1 and E2F2 levels were also increased and positively correlated. E2f1 -/- and E2f2 -/- mice were resistant to DEN-HFD-induced hepatocarcinogenesis and associated lipid accumulation. Administration of DEN-HFD in E2f1 -/- and E2f2 -/- mice enhanced fatty acid oxidation (FAO) and increased expression of Cpt2, an enzyme essential for FAO, whose downregulation is linked to NAFLD-related hepatocarcinogenesis. These results were recapitulated following E2f2 knockdown in liver, and overexpression of E2f2 elicited opposing effects. E2F2 binding to the Cpt2 promoter was enhanced in DEN-HFD-administered mouse livers compared with controls, implying a direct role for E2F2 in transcriptional repression. In human HCC, E2F1 and E2F2 expressions inversely correlated with CPT2 expression. Collectively, these results indicate that activation of the E2F1-E2F2-CPT2 axis provides a lipid-rich environment required for hepatocarcinogenesis. SIGNIFICANCE: These findings identify E2F1 and E2F2 transcription factors as metabolic drivers of hepatocellular carcinoma, where deletion of just one is sufficient to prevent disease. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/11/2874/F1.large.jpg.
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Affiliation(s)
- Francisco González-Romero
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain
| | - Daniela Mestre
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain.,BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
| | - Igor Aurrekoetxea
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain.,BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
| | - Colm J O'Rourke
- Department of Health and Medical Sciences, Biotech Research and Innovation Center, University of Copenhagen, Denmark
| | - Jesper B Andersen
- Department of Health and Medical Sciences, Biotech Research and Innovation Center, University of Copenhagen, Denmark
| | - Ashwin Woodhoo
- Center for Cooperative Research in Bioscience (CIC bioGUNE), Derio, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Miguel Tamayo-Caro
- Center for Cooperative Research in Bioscience (CIC bioGUNE), Derio, Spain
| | - Marta Varela-Rey
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), CIBERehd Derio, Spain
| | | | - Beatriz Gómez-Santos
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain
| | - Diego Sáenz de Urturi
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain
| | - Maitane Núñez-García
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain
| | - Juan L García-Rodríguez
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain
| | - Larraitz Fernández-Ares
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain.,BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
| | - Xabier Buqué
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain.,BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
| | - Ainhoa Iglesias-Ara
- Department of Genetic, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of Basque Country UPV/EHU, Leioa, Spain
| | | | - Virginia Gutierrez De Juan
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), CIBERehd Derio, Spain
| | - Teresa C Delgado
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), CIBERehd Derio, Spain
| | - Naroa Goikoetxea-Usandizaga
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), CIBERehd Derio, Spain
| | | | | | - Igotz Delgado
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain
| | - Maria J Perugorria
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute, Donostia University Hospital, University of the Basque Country UPV/EHU, CIBERehd, San Sebastian, Spain.,Department of Medicine, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Gaizka Errazti
- BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
| | - Lorena Mosteiro
- BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
| | - Sonia Gaztambide
- BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain.,Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, CIBERDEM, CIBERER, Leioa, Spain
| | | | - Paula Iruzubieta
- Department of Gastroenterology and Hepatology, Marqués de Valdecilla University Hospital, Santander, Spain
| | - Javier Crespo
- Department of Gastroenterology and Hepatology, Marqués de Valdecilla University Hospital, Santander, Spain
| | - Jesus M Banales
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain.,Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute, Donostia University Hospital, University of the Basque Country UPV/EHU, CIBERehd, San Sebastian, Spain
| | - Maria L Martínez-Chantar
- Liver Disease Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), CIBERehd Derio, Spain
| | - Luis Castaño
- BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain.,Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, CIBERDEM, CIBERER, Leioa, Spain
| | - Ana M Zubiaga
- Department of Genetic, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of Basque Country UPV/EHU, Leioa, Spain
| | - Patricia Aspichueta
- Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country UPV/EHU, Leioa, Spain. .,BioCruces Bizkaia Health Research Institute, Cruces University Hospital, CIBERehd, Barakaldo, Spain
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10
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Zhang Q, Koser SL, Donkin SS. Identification of promoter response elements that mediate propionate induction of bovine cytosolic phosphoenolpyruvate carboxykinase (PCK1) gene transcription. J Dairy Sci 2021; 104:7252-7261. [PMID: 33741163 DOI: 10.3168/jds.2020-18993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 12/08/2020] [Indexed: 11/19/2022]
Abstract
Cytosolic phosphoenolpyruvate carboxykinase (PCK1) is a key enzyme for gluconeogenesis that is positively regulated by propionate in bovines at the transcription level. The specific elements that determine propionate responsiveness within the bovine PCK1 promoter are unknown. In silico promoter analysis of the bovine PCK1 gene revealed several clusters of transcription factor binding sites. In the present study, we determined the essentiality of the putative cyclic AMP response element (CRE) at -94 through -87 bp and the 2 putative hepatic nuclear factor 4α (HNF4α) binding elements at +68 through +72 and -1,078 through -1,074, respectively, in mediating bovine PCK1 promoter responses to propionate and other regulators, including butyrate, cyclic AMP (cAMP), and glucocorticoids. The wild-type bovine PCK1 promoter [PCK1(WT)] was ligated to a luciferase reporter gene and transfected into rat hepatoma (H4IIE) cells. Activities of PCK1(WT) were induced by approximately 2-, 2-, 4-, 8-, 9-, 18-, and 16-fold respectively when exposed to cAMP (as 1.0 mM 8-Br-cAMP), 5.0 μM dexamethasone, cAMP + dexamethasone, 2.5 mM propionate, cAMP + propionate, cAMP + dexamethasone + propionate, and 2.5 mM butyrate. Seven mutants lacking either one single site, 2 of the 3 sites, or all 3 sites, generated by site-directed mutagenesis, were tested. Responses to propionate and all other treatments were completely abolished when CRE at -94 through -87 bp and HNF4α at +68 through +72 bp were both deleted. Our data indicate that these 2 regulatory elements act synergistically to mediate the bovine PCK1 promoter responses to propionate as well as butyrate, cAMP, and dexamethasone. The activation of PCK1 through these regulatory elements serves to activate the metabolic potential of bovine toward gluconeogenesis when the primary substrate for gluconeogenesis, propionate, is also present.
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Affiliation(s)
- Q Zhang
- Adisseo Life Science Co. Ltd., Shanghai 201204, PR China
| | - S L Koser
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907
| | - S S Donkin
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907.
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11
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cAMP Signaling in Pathobiology of Alcohol Associated Liver Disease. Biomolecules 2020; 10:biom10101433. [PMID: 33050657 PMCID: PMC7600246 DOI: 10.3390/biom10101433] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023] Open
Abstract
The importance of cyclic adenosine monophosphate (cAMP) in cellular responses to extracellular signals is well established. Many years after discovery, our understanding of the intricacy of cAMP signaling has improved dramatically. Multiple layers of regulation exist to ensure the specificity of cellular cAMP signaling. Hence, disturbances in cAMP homeostasis could arise at multiple levels, from changes in G protein coupled receptors and production of cAMP to the rate of degradation by phosphodiesterases. cAMP signaling plays critical roles in metabolism, inflammation and development of fibrosis in several tissues. Alcohol-associated liver disease (ALD) is a multifactorial condition ranging from a simple steatosis to steatohepatitis and fibrosis and ultimately cirrhosis, which might lead to hepatocellular cancer. To date, there is no FDA-approved therapy for ALD. Hence, identifying the targets for the treatment of ALD is an important undertaking. Several human studies have reported the changes in cAMP homeostasis in relation to alcohol use disorders. cAMP signaling has also been extensively studied in in vitro and in vivo models of ALD. This review focuses on the role of cAMP in the pathobiology of ALD with emphasis on the therapeutic potential of targeting cAMP signaling for the treatment of various stages of ALD.
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12
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Yang J, Ueharu H, Mishina Y. Energy metabolism: A newly emerging target of BMP signaling in bone homeostasis. Bone 2020; 138:115467. [PMID: 32512164 PMCID: PMC7423769 DOI: 10.1016/j.bone.2020.115467] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 12/11/2022]
Abstract
Energy metabolism is the process of generating energy (i.e. ATP) from nutrients. This process is indispensable for cell homeostasis maintenance and responses to varying conditions. Cells require energy for growth and maintenance and have evolved to have multiple pathways to produce energy. Both genetic and functional studies have demonstrated that energy metabolism, such as glucose, fatty acid, and amino acid metabolism, plays important roles in the formation and function of bone cells including osteoblasts, osteocytes, and osteoclasts. Dysregulation of energy metabolism in bone cells consequently disturbs the balance between bone formation and bone resorption. Metabolic diseases have also been reported to affect bone homeostasis. Bone morphogenic protein (BMP) signaling plays critical roles in regulating the formation and function of bone cells, thus affecting bone development and homeostasis. Mutations of BMP signaling-related genes in mice have been reported to show abnormalities in energy metabolism in many tissues, including bone. In addition, BMP signaling correlates with critical signaling pathways such as mTOR, HIF, Wnt, and self-degradative process autophagy to coordinate energy metabolism and bone homeostasis. These findings will provide a newly emerging target of BMP signaling and potential therapeutic strategies and the improved management of bone diseases. This review summarizes the recent advances in our understanding of (1) energy metabolism in regulating the formation and function of bone cells, (2) function of BMP signaling in whole body energy metabolism, and (3) mechanistic interaction of BMP signaling with other signaling pathways and biological processes critical for energy metabolism and bone homeostasis.
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Affiliation(s)
- Jingwen Yang
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA; The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory for Oral Biomedicine of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei 430079, China.
| | - Hiroki Ueharu
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuji Mishina
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
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13
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Zhang H, Yang L, Wang Y, Huang W, Li Y, Chen S, Song G, Ren L. Oxymatrine alleviated hepatic lipid metabolism via regulating miR-182 in non-alcoholic fatty liver disease. Life Sci 2020; 257:118090. [PMID: 32679144 DOI: 10.1016/j.lfs.2020.118090] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 12/19/2022]
Abstract
AIMS This study aimed to investigate oxymatrine via regulating miR-182 improved the hepatic lipid accumulation in non-alcoholic fatty liver disease (NAFLD) model. MATERIALS AND METHODS Wistar rats were fed high-fat and high-fructose diet (HFDHFr group) for 4 weeks and HepG2 cells were treated with palmitic acid (PA group), and then were given oxymatrine intervention. The expression profiles of miRNAs were accessed by RNA sequencing (RNA-Seq). Hematoxylin-eosin (HE) staining and Oil Red O staining were used to observe the inflammation and lipid accumulation in liver. The levels of sterol regulatory element binding protein-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty-acid synthase (FAS) and carnitine palmitoyltransferase 1A (CPT-1A) were detected by RT-qPCR and Western blotting, respectively. Cell viability was detected by Cell Counting Kit-8 (CCK-8). KEY FINDINGS miR-182 was down-regulated in the HFDHFr group and PA group. Oxymatrine reduced body weight, and improved glucose tolerance and insulin resistance in the HFDHFr + OMT group compared with HFDHFr group. In addition, oxymatrine reduced the ratio (liver weight/body weight), the content of triglycerides (TG), hepatic lipid accumulation and steatosis. The levels of SREBP-1c, ACC, and FAS were significantly decreased, while the CPT-1A level was obviously elevated after oxymatrine intervention (P < 0.05). In vivo, miR-182 knockdown increased the levels of SREBP-1c, ACC and FAS, while reduced the CPT-1A level. Additionally, oxymatrine attenuated the effects of miR-182 inhibitor on lipid accumulation. SIGNIFICANCE We presented a possible mechanism that oxymatrine alleviated hepatic lipid metabolism via regulating miR-182 in NAFLD model.
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Affiliation(s)
- He Zhang
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Liying Yang
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Yichao Wang
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Wenli Huang
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Yang Li
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Shuchun Chen
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Guangyao Song
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China
| | - Luping Ren
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China; Hebei Key Laboratory of Metabolic Diseases, Hebei General Hospital, Shijiazhuang, China.
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14
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Wang H, Cheng Y, Liu Y, Shi J, Cheng Z. Montelukast promotes mitochondrial biogenesis via CREB/PGC-1α in human bronchial epithelial cells. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2020; 47:4234-4239. [PMID: 31722576 DOI: 10.1080/21691401.2019.1687502] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bronchial epithelial mitochondrial dysfunction including impaired mitochondrial biogenesis has been linked with the initiation and development of bronchial asthma. Montelukast, a robust antagonist of cysteinyl leukotriene receptors, has been widely applied for the therapies of bronchial asthma. However, the effects of montelukast in airway epithelial mitochondrial dysfunction are less reported. In the present study, we report that montelukast treatment in human bronchial epithelial cells of Beas-2b increased the expressions of PGC-1α, NRF-1 and TFAM. As expected, montelukast promoted mitochondrial biogenesis in Beas-2b cells through increasing mitochondrial mass, mtDNA/nDNA and the expression of cytochrome B. Importantly, we found that montelukast caused a functional gain in mitochondria of Beas-2b cells. Mechanistically, we found that montelukast treatment increased intracellular cAMP levels and activation of CREB. Blockage of CREB with H89 abolished montelukast-induced expression of PGC-1α. These findings report a novel pharmacological function of montelukast in stimulating mitochondrial biogenesis in Beas-2b cells, mediating by the CREB/PGC-1α pathway.
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Affiliation(s)
- Huan Wang
- Department of Respiratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Yali Cheng
- Department of Respiratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Ying Liu
- Department of Respiratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Jiang Shi
- Department of Respiratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Zhe Cheng
- Department of Respiratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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15
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Guan X, Wang Y, Kai G, Zhao S, Huang T, Li Y, Xu Y, Zhang L, Pang T. Cerebrolysin Ameliorates Focal Cerebral Ischemia Injury Through Neuroinflammatory Inhibition via CREB/PGC-1α Pathway. Front Pharmacol 2019; 10:1245. [PMID: 31695614 PMCID: PMC6818051 DOI: 10.3389/fphar.2019.01245] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 09/27/2019] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation is one of the important factors aggravating brain injury after ischemic stroke. We aimed to investigate the effects of cerebrolysin (CBL) on neuroinflammation in vivo and in vitro and the underlying mechanisms. The gene expressions of pro-inflammatory factors and anti-inflammatory factors were analyzed by real time PCR in rat transient middle cerebral artery occlusion (tMCAO) model, lipopolysaccharides-induced neuroinflammatory mice model and LPS-treated mouse primary microglia cells. The neuroprotective effects of CBL were evaluated by infarct size, Longa test and Rotarod test for long-term functional recovery in rats subjected to ischemia. The role of CREB/PGC-1α pathway in anti-neuroinflammatory effect of CBL was also determined by real time PCR and Western blotting. In the tMCAO model, administration of CBL at 3 h post-ischemia reduced infarct volume, promoted long-term functional recovery, decreased the gene expression of pro-inflammatory factors and increased the gene expression of anti-inflammatory factors. Correspondingly, in LPS-induced neuroinflammatory mice model, CBL treatment attenuated sickness behavior, decreased the gene expression of pro-inflammatory factors, and increased the gene expression of anti-inflammatory factors. In in vitro and in vivo experiments, CBL increased the protein expression levels of PGC-1α and phosphorylated CREB to play anti-inflammatory effect. Additionally, the application of the specific CREB inhibitor, 666-15 compound could effectively reverse the anti-inflammatory effect of CBL in primary mouse microglia cells and anti-ischemic brain injury of CBL in rats subjected to tMCAO. In conclusion, CBL ameliorated cerebral ischemia injury through reducing neuroinflammation partly via the activation of CREB/PGC-1α pathway and may play a therapeutic role as anti-neuroinflammatory agents in the brain disorders associated with neuroinflammation.
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Affiliation(s)
- Xin Guan
- Jiangsu Key Laboratory of Drug Screening, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Yunjie Wang
- Jiangsu Key Laboratory of Drug Screening, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Guoyin Kai
- College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shunyi Zhao
- Jiangsu Key Laboratory of Drug Screening, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Tingyu Huang
- Guangdong Long Fu Pharmaceutical Co., Ltd., Zhongshan, China
| | - Youzhen Li
- Guangdong Long Fu Pharmaceutical Co., Ltd., Zhongshan, China
| | - Yuan Xu
- School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Luyong Zhang
- Jiangsu Key Laboratory of Drug Screening, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Tao Pang
- Jiangsu Key Laboratory of Drug Screening, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
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16
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Tributyrin Inhibits Ethanol-Induced Epigenetic Repression of CPT-1A and Attenuates Hepatic Steatosis and Injury. Cell Mol Gastroenterol Hepatol 2019; 9:569-585. [PMID: 31654770 PMCID: PMC7078548 DOI: 10.1016/j.jcmgh.2019.10.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 12/12/2022]
Abstract
UNLABELLED Ethanol-mediated down-regulation of carnitine palmitoyltransferase-1 (CPT-1A) gene expression plays a major role in the development of hepatic steatosis; however, the underlying mechanisms are not completely elucidated. Tributyrin, a butyrate prodrug that can inhibit histone deacetylase (HDAC) activity, attenuates hepatic steatosis and injury. The present study examined the beneficial effect of tributyrin/butyrate in attenuating ethanol-induced pathogenic epigenetic mechanisms affecting CPT-1A promoter-histone modifications and gene expression and hepatic steatosis/injury. METHODS Mice were fed a liquid Lieber-DeCarli diet (Research Diet Inc, New Brunswick, NJ) with or without ethanol for 4 weeks. In a subset of mice, tributyrin (2 g/kg) was administered orally by gavage. Primary rat hepatocytes were treated with 50 mmol/L ethanol and/or 2 mmol/L butyrate. Gene expression and epigenetic modifications at the CPT-1A promoter were analyzed by chromatin immunoprecipitation analysis. RESULTS In vivo, ethanol induced hepatic CPT-1A promoter histone H3K9 deacetylation, which is indicative of a repressive chromatin state, and decreased CPT-1A gene expression. Our data identified HDAC1 as the predominant HDAC causing CPT-1A promoter histone H3K9 deacetylation and epigenetic down-regulation of gene expression. Significantly, Specificity Protein 1 (SP1) and Hepatocyte Nuclear Factor 4 Alpha (HNF4α) participated in the recruitment of HDAC1 to the proximal and distal regions of CPT-1A promoter, respectively, and mediated transcriptional repression. Importantly, butyrate, a dietary HDAC inhibitor, attenuated ethanol-induced recruitment of HDAC1 and facilitated p300-HAT binding by enabling SP1/p300 interaction at the proximal region and HNF4α/peroxisomal proliferator-activated receptor-γ coactivator-1α/p300 interactions at the distal region, leading to promoter histone acetylation and enhanced CPT-1A transcription. CONCLUSIONS This study identifies HDAC1-mediated repressive epigenetic mechanisms that underlie an ethanol-mediated decrease in CPT-1A expression. Importantly, tributyrin/butyrate inhibits HDAC1, rescues CPT-1A expression, and attenuates ethanol-mediated hepatic steatosis and injury, suggesting its potential use in therapeutic strategies for alcoholic liver disease.
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17
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The pathobiology of polycystic kidney disease from a metabolic viewpoint. Nat Rev Nephrol 2019; 15:735-749. [PMID: 31488901 DOI: 10.1038/s41581-019-0183-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2019] [Indexed: 02/07/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) affects an estimated 1 in 1,000 people and slowly progresses to end-stage renal disease (ESRD) in about half of these individuals. Tolvaptan, a vasopressin 2 receptor blocker, has been approved by regulatory authorities in many countries as a therapy to slow cyst growth, but additional treatments that target dysregulated signalling pathways in cystic kidney and liver are needed. Metabolic reprogramming is a prominent feature of cystic cells and a potentially important contributor to the pathophysiology of ADPKD. A number of pathways previously implicated in the pathogenesis of the disease, such as dysregulated mTOR and primary ciliary signalling, have roles in metabolic regulation and may exert their effects through this mechanism. Some of these pathways are amenable to manipulation through dietary modifications or drug therapies. Studies suggest that polycystin-1 and polycystin-2, which are encoded by PKD1 and PKD2, respectively (the genes that are mutated in >99% of patients with ADPKD), may in part affect cellular metabolism through direct effects on mitochondrial function. Mitochondrial dysfunction could alter the redox state and cellular levels of acetyl-CoA, resulting in altered histone acetylation, gene expression, cytoskeletal architecture and response to cellular stress, and in an immunological response that further promotes cyst growth and fibrosis.
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18
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Du Q, Tan Z, Shi F, Tang M, Xie L, Zhao L, Li Y, Hu J, Zhou M, Bode A, Luo X, Cao Y. PGC1α/CEBPB/CPT1A axis promotes radiation resistance of nasopharyngeal carcinoma through activating fatty acid oxidation. Cancer Sci 2019; 110:2050-2062. [PMID: 30945396 PMCID: PMC6550130 DOI: 10.1111/cas.14011] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 12/19/2022] Open
Abstract
The PPAR coactivator-1α (PGC1α) is an important transcriptional co-activator in control of fatty acid metabolism. Mitochondrial fatty acid oxidation (FAO) is the primary pathway for the degradation of fatty acids and promotes NADPH and ATP production. Our previous study demonstrated that upregulation of carnitine palmitoyl transferase 1 A (CPT1A), the key regulator of FAO, promotes radiation resistance of nasopharyngeal carcinoma (NPC). In this study, we found that high expression of PGC1α is associated with poor overall survival in NPC patients after radiation treatment. Targeting PGC1α could sensitize NPC cells to radiotherapy. Mechanically, PGC1α binds to CCAAT/enhancer binding protein β (CEBPB), a member of the transcription factor family of CEBP, to promote CPT1A transcription, resulting in activation of FAO. Our results revealed that the PGC1α/CEBPB/CPT1A/FAO signaling axis promotes radiation resistance of NPC. These findings indicate that the expression of PGC1α could be a prognostic indicator of NPC, and targeting FAO in NPC with high expression of PGC1α might improve the therapeutic efficacy of radiotherapy.
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Affiliation(s)
- Qianqian Du
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Zheqiong Tan
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Feng Shi
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Min Tang
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Longlong Xie
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Lin Zhao
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Yueshuo Li
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Jianmin Hu
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Min Zhou
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China
| | - Ann Bode
- The Hormel Institute, University of Minnesota, Austin, Minnesota
| | - Xiangjian Luo
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Molecular Imaging Research Center of Central South University, Changsha, China
| | - Ya Cao
- Key Laboratory of Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute School of Basic Medicine Science, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Molecular Imaging Research Center of Central South University, Changsha, China.,Research Center for Technologies of Nucleic Acid-Based Diagnostics and Therapeutics Hunan Province, Changsha, China.,National Joint Engineering Research Center for Genetic Diagnostics of Infectious Diseases and Cancer, Changsha, China
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19
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Yao C, Pang D, Lu C, Xu A, Huang P, Ouyang H, Yu H. Data Mining and Validation of AMPK Pathway as a Novel Candidate Role Affecting Intramuscular Fat Content in Pigs. Animals (Basel) 2019; 9:ani9040137. [PMID: 30939765 PMCID: PMC6523794 DOI: 10.3390/ani9040137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Intramuscular fat (IMF) is increasingly being recognized as a key meat trait in the modern pork industry. The aims of this research were to identify potential signaling pathways associated with IMF content in the longissimus dorsi (LD) muscle of different pig breeds and investigate the gene expression levels in the screened signaling pathways. Our results indicated that the AMPK signaling pathway may be related to IMF deposition in the LD muscle of pigs. The results of qRT-PCR analysis showed that the expression of ten key hub genes (AMPK, ADIPOR1, ADIPOR2, LKB1, CAMKKβ, CPT1A, CPT1B, PGC-1α, CD36, and ACC1) differed between the LD muscle of Min and Large White pigs. The protein expression levels of AMPK, LKB1, CaMKK2, CPT1A, and ACC1 were similar to the genes expression patterns in the LD muscle of Large White pigs. The results of this study provide novel insights into the regulatory function of the AMPK signaling pathway in relation to the IMF content in the LD muscle of different pigs. Abstract Intramuscular fat (IMF) is an important economic trait for pork quality and a complex quantitative trait regulated by multiple genes. The objective of this work was to investigate the novel transcriptional effects of a multigene pathway on IMF deposition in the longissimus dorsi (LD) muscles of pigs. Potential signaling pathways were screened by mining data from three gene expression profiles in the Gene Expression Omnibus (GEO) database. We designed quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) arrays for the candidate signaling pathways to verify the results in the LD muscles of two pig breeds with different IMF contents (Large White and Min). Western blot analysis was used to detect the expression levels of several candidate proteins. Our results showed that the AMPK signaling pathway was screened via bioinformatics analysis. Ten key hub genes of this signaling pathway (AMPK, ADIPOR1, ADIPOR2, LKB1, CAMKKβ, CPT1A, CPT1B, PGC-1α, CD36, and ACC1) were differentially expressed between the Large White and Min pigs. Western blot analysis further confirmed that LKB1/CaMKK2-AMPK-ACC1-CPT1A axis dominates the activity of AMPK signaling pathway. Statistical analyses revealed that AMPK signaling pathway activity clearly varied among the two pig breeds. Based on these results, we concluded that the activation of the AMPK signaling pathway plays a positive role in reducing IMF deposition in pigs.
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Affiliation(s)
- Chaogang Yao
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Daxin Pang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Chao Lu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Aishi Xu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Peixuan Huang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Hongsheng Ouyang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
| | - Hao Yu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun 130062, China.
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20
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PGC1A regulates the IRS1:IRS2 ratio during fasting to influence hepatic metabolism downstream of insulin. Proc Natl Acad Sci U S A 2019; 116:4285-4290. [PMID: 30770439 PMCID: PMC6410797 DOI: 10.1073/pnas.1815150116] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Precise modulation of hepatic glucose metabolism is crucial during the fasting and feeding cycle and is controlled by the actions of circulating insulin and glucagon. The insulin-signaling pathway requires insulin receptor substrate 1 (IRS1) and IRS2, which are found to be dysregulated in diabetes and obesity. The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1A) is a fasting-induced transcriptional coactivator. In nonalcoholic fatty liver disease and in patients with type 2 diabetes, low hepatic PGC1A levels are associated with insulin resistance. However, how PGC1A activity impacts the hepatic insulin-signaling pathway is still unclear. We used gain- and loss-of-function models in mouse primary hepatocytes and measured hepatocyte insulin response by gene and protein expression and ex vivo glucose production. We found that the PGC1A level determines the relative ratio of IRS1 and IRS2 in hepatocytes, impacting insulin receptor signaling via protein kinase B/AKT (AKT). PGC1A drove the expression of IRS2 downstream of glucagon signaling while simultaneously reducing IRS1 expression. We illustrate that glucagon- or PGC1A-induced IRS2 expression was dependent on cAMP Response Element Binding Protein activity and that this was essential for suppression of hepatocyte gluconeogenesis in response to insulin in vitro. We also show that increased hepatic PGC1A improves glucose homeostasis in vivo, revealing a counterregulatory role for PGC1A in repressing uncontrolled glucose production in response to insulin signaling. These data highlight a mechanism by which PGC1A plays dual roles in the control of gluconeogenesis during the fasting-to-fed transition through regulated balance between IRS1 and IRS2 expression.
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21
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Sato T, Muramatsu N, Ito Y, Yamamoto Y, Nagasawa T. L-Lysine Attenuates Hepatic Steatosis in Senescence-Accelerated Mouse Prone 8 Mice. J Nutr Sci Vitaminol (Tokyo) 2018; 64:192-199. [PMID: 29962430 DOI: 10.3177/jnsv.64.192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Non-alcoholic hepatic steatosis is a phenotype of metabolic syndrome, and aging is a risk factor for this condition. Senescence-accelerated mouse prone 8 (SAMP8) is a murine model for studying aging-associated disorders. We here investigated the effect of dietary supplementation with L-lysine (Lys) on non-alcoholic hepatic steatosis in SAMP8 mice. Triglyceride (TG) and cholesterol (Chol) accumulated in the livers of SAMP8 mice fed a standard diet at 36 wk of age. However, intake of a Lys-rich diet for 2 mo prevented the accumulation of TG and Chol in the liver. Plasma alanine aminotransferase activity, an index of liver injury, was decreased by Lys. The mRNA expression levels of peroxisome proliferator-activated receptor gamma coactivator 1-α and carnitine palmitoyltransferase 1a, which regulate β-oxidation, were increased in the livers of SAMP8 mice fed the Lys-rich diet. Taken together, our study suggests dietary intake of Lys prevents hepatic steatosis by stimulating β-oxidation in SAMP8 mice.
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Affiliation(s)
- Tomonori Sato
- Department of Bioresources Science, The United Graduate School of Agricultural Sciences, Iwate University
| | - Nao Muramatsu
- Department of Biological Chemistry and Food Science, Graduate School of Agriculture, Iwate University
| | - Yoshiaki Ito
- Department of Bioresources Science, The United Graduate School of Agricultural Sciences, Iwate University.,Department of Biological Chemistry and Food Science, Graduate School of Agriculture, Iwate University
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University.,Department of Basic Veterinary Science, United Graduate School of Veterinary Science, Gifu University
| | - Takashi Nagasawa
- Department of Bioresources Science, The United Graduate School of Agricultural Sciences, Iwate University.,Department of Biological Chemistry and Food Science, Graduate School of Agriculture, Iwate University
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22
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Wahlang B, McClain C, Barve S, Gobejishvili L. Role of cAMP and phosphodiesterase signaling in liver health and disease. Cell Signal 2018; 49:105-115. [PMID: 29902522 PMCID: PMC6445381 DOI: 10.1016/j.cellsig.2018.06.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/08/2018] [Accepted: 06/09/2018] [Indexed: 02/06/2023]
Abstract
Liver disease is a significant health problem worldwide with mortality reaching around 2 million deaths a year. Non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are the major causes of chronic liver disease. Pathologically, NAFLD and ALD share similar patterns of hepatic disorders ranging from simple steatosis to steatohepatitis, fibrosis and cirrhosis. It is becoming increasingly important to identify new pharmacological targets, given that there is no FDA-approved therapy yet for either NAFLD or ALD. Since the evolution of liver diseases is a multifactorial process, several mechanisms involving parenchymal and non-parenchymal hepatic cells contribute to the initiation and progression of liver pathologies. Moreover, certain protective molecular pathways become repressed during liver injury including signaling pathways such as the cyclic adenosine monophosphate (cAMP) pathway. cAMP, a key second messenger molecule, regulates various cellular functions including lipid metabolism, inflammation, cell differentiation and injury by affecting gene/protein expression and function. This review addresses the current understanding of the role of cAMP metabolism and consequent cAMP signaling pathway(s) in the context of liver health and disease. The cAMP pathway is extremely sophisticated and complex with specific cellular functions dictated by numerous factors such abundance, localization and degradation by phosphodiesterases (PDEs). Furthermore, because of the distinct yet divergent roles of both of its effector molecules, the cAMP pathway is extensively targeted in liver injury to modify its role from physiological to therapeutic, depending on the hepatic condition. This review also examines the behavior of the cAMP-dependent pathway in NAFLD, ALD and in other liver diseases and focuses on PDE inhibition as an excellent therapeutic target in these conditions.
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Affiliation(s)
- Banrida Wahlang
- University of Louisville Alcohol Research Center, School of Medicine, University of Louisville, KY, USA; Department of Medicine, School of Medicine, University of Louisville, KY, USA
| | - Craig McClain
- University of Louisville Alcohol Research Center, School of Medicine, University of Louisville, KY, USA; Department of Medicine, School of Medicine, University of Louisville, KY, USA; Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, KY, USA; Hepatobiology & Toxicology Center, School of Medicine, University of Louisville, KY, USA; Robley Rex Louisville VAMC, Louisville, KY, USA
| | - Shirish Barve
- University of Louisville Alcohol Research Center, School of Medicine, University of Louisville, KY, USA; Department of Medicine, School of Medicine, University of Louisville, KY, USA; Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, KY, USA; Hepatobiology & Toxicology Center, School of Medicine, University of Louisville, KY, USA
| | - Leila Gobejishvili
- University of Louisville Alcohol Research Center, School of Medicine, University of Louisville, KY, USA; Department of Medicine, School of Medicine, University of Louisville, KY, USA; Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, KY, USA; Hepatobiology & Toxicology Center, School of Medicine, University of Louisville, KY, USA.
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23
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Pérez-Mendoza M, Rivera-Zavala JB, Rodríguez-Guadarrama AH, Montoya-Gomez LM, Carmona-Castro A, Díaz-Muñoz M, Miranda-Anaya M. Daily cycle in hepatic lipid metabolism in obese mice, Neotomodon alstoni: Sex differences. Chronobiol Int 2018; 35:643-657. [PMID: 29370528 DOI: 10.1080/07420528.2018.1424178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Disruption of circadian rhythms influences the pathogenesis of obesity, particularly with the basic regulation of food intake and metabolism. A link between metabolism and the circadian clock is the peroxisome proliferator-activated receptors (PPARs). The Neotomodon alstoni mouse, known as the "Mexican volcano mouse," may develop obesity if fed a normo-caloric diet. This manuscript documents the changes in part of the hepatic lipid homeostasis in both sexes of lean and obese N. alstoni mice, comparing the daily changes in the BMAL1 clock protein, in regulators of lipid metabolism (PGC-1α, PPARα-γ, SREBP-1c, and CPT-1α) and in free fatty acid (FFA) and hepatic triacylglyceride (TAG) metabolites in light-dark cycles. Hepatic tissue and blood were collected at 5, 10, 15, 19, and 24 h. Samples were analyzed by western blotting to determine the relative presence of protein. The results indicate that obesity affects daily changes in lipid metabolism and the BMAL1 profile in females considerably more than in males. These results suggest that the impact of obesity on lipid metabolism has important differences according to sex.
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Affiliation(s)
- Moisés Pérez-Mendoza
- a Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias , Universidad Nacional Autónoma de México , Juriquilla , Qro
| | - Julieta Berenice Rivera-Zavala
- a Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias , Universidad Nacional Autónoma de México , Juriquilla , Qro
| | - Asael H Rodríguez-Guadarrama
- a Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias , Universidad Nacional Autónoma de México , Juriquilla , Qro
| | - Luis M Montoya-Gomez
- a Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias , Universidad Nacional Autónoma de México , Juriquilla , Qro
| | - Agustín Carmona-Castro
- b Departamento de Biología Celular; Facultad de Ciencias , Ciudad Universitaria, Universidad Nacional Autónoma de México , Ciudad de México , México
| | - Mauricio Díaz-Muñoz
- c Departamento de Neurobiología Celular y Molecular , Instituto de Neurobiología, Universidad Nacional Autónoma de México , Campus Juriquilla, Querétaro, Qro , México
| | - Manuel Miranda-Anaya
- a Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias , Universidad Nacional Autónoma de México , Juriquilla , Qro
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24
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Abstract
Cellular lipid metabolism and homeostasis are controlled by sterol regulatory-element binding proteins (SREBPs). In addition to performing canonical functions in the transcriptional regulation of genes involved in the biosynthesis and uptake of lipids, genome-wide system analyses have revealed that these versatile transcription factors act as important nodes of convergence and divergence within biological signalling networks. Thus, they are involved in myriad physiological and pathophysiological processes, highlighting the importance of lipid metabolism in biology. Changes in cell metabolism and growth are reciprocally linked through SREBPs. Anabolic and growth signalling pathways branch off and connect to multiple steps of SREBP activation and form complex regulatory networks. In addition, SREBPs are implicated in numerous pathogenic processes such as endoplasmic reticulum stress, inflammation, autophagy and apoptosis, and in this way, they contribute to obesity, dyslipidaemia, diabetes mellitus, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, chronic kidney disease, neurodegenerative diseases and cancers. This Review aims to provide a comprehensive understanding of the role of SREBPs in physiology and pathophysiology at the cell, organ and organism levels.
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Affiliation(s)
- Hitoshi Shimano
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba 305-8577, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Ryuichiro Sato
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
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25
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Simcox J, Geoghegan G, Maschek JA, Bensard CL, Pasquali M, Miao R, Lee S, Jiang L, Huck I, Kershaw EE, Donato AJ, Apte U, Longo N, Rutter J, Schreiber R, Zechner R, Cox J, Villanueva CJ. Global Analysis of Plasma Lipids Identifies Liver-Derived Acylcarnitines as a Fuel Source for Brown Fat Thermogenesis. Cell Metab 2017; 26:509-522.e6. [PMID: 28877455 PMCID: PMC5658052 DOI: 10.1016/j.cmet.2017.08.006] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 04/27/2017] [Accepted: 08/08/2017] [Indexed: 12/30/2022]
Abstract
Cold-induced thermogenesis is an energy-demanding process that protects endotherms against a reduction in ambient temperature. Using non-targeted liquid chromatography-mass spectrometry-based lipidomics, we identified elevated levels of plasma acylcarnitines in response to the cold. We found that the liver undergoes a metabolic switch to provide fuel for brown fat thermogenesis by producing acylcarnitines. Cold stimulates white adipocytes to release free fatty acids that activate the nuclear receptor HNF4α, which is required for acylcarnitine production in the liver and adaptive thermogenesis. Once in circulation, acylcarnitines are transported to brown adipose tissue, while uptake into white adipose tissue and liver is blocked. Finally, a bolus of L-carnitine or palmitoylcarnitine rescues the cold sensitivity seen with aging. Our data highlight an elegant mechanism whereby white adipose tissue provides long-chain fatty acids for hepatic carnitilation to generate plasma acylcarnitines as a fuel source for peripheral tissues in mice.
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Affiliation(s)
- Judith Simcox
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Gisela Geoghegan
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - John Alan Maschek
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Claire L Bensard
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Marzia Pasquali
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ren Miao
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Sanghoon Lee
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Lei Jiang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ian Huck
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Erin E Kershaw
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Anthony J Donato
- Department of Exercise and Sport Science, Geriatric Research, Education, and Clinical Center, Veteran's Affairs Medical Center, Salt Lake City, UT 84112, USA
| | - Udayan Apte
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nicola Longo
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - James Cox
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Claudio J Villanueva
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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26
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Kim SP, Li Z, Zoch ML, Frey JL, Bowman CE, Kushwaha P, Ryan KA, Goh BC, Scafidi S, Pickett JE, Faugere MC, Kershaw EE, Thorek DLJ, Clemens TL, Wolfgang MJ, Riddle RC. Fatty acid oxidation by the osteoblast is required for normal bone acquisition in a sex- and diet-dependent manner. JCI Insight 2017; 2:92704. [PMID: 28814665 DOI: 10.1172/jci.insight.92704] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 07/19/2017] [Indexed: 12/20/2022] Open
Abstract
Postnatal bone formation is influenced by nutritional status and compromised by disturbances in metabolism. The oxidation of dietary lipids represents a critical source of ATP for many cells but has been poorly studied in the skeleton, where the prevailing view is that glucose is the primary energy source. Here, we examined fatty acid uptake by bone and probed the requirement for fatty acid catabolism during bone formation by specifically disrupting the expression of carnitine palmitoyltransferase 2 (Cpt2), an obligate enzyme in fatty acid oxidation, in osteoblasts and osteocytes. Radiotracer studies demonstrated that the skeleton accumulates a significant fraction of postprandial fatty acids, which was equal to or in excess of that acquired by skeletal muscle or adipose tissue. Female, but not male, Cpt2 mutant mice exhibited significant impairments in postnatal bone acquisition, potentially due to an inability of osteoblasts to modify fuel selection. Intriguingly, suppression of fatty acid utilization by osteoblasts and osteocytes also resulted in the development of dyslipidemia and diet-dependent modifications in body composition. Taken together, these studies demonstrate a requirement for fatty acid oxidation during bone accrual and suggest a role for the skeleton in lipid homeostasis.
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Affiliation(s)
| | - Zhu Li
- Department of Orthopaedic Surgery
| | | | | | | | | | | | | | - Susanna Scafidi
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Julie E Pickett
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daniel L J Thorek
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cancer Molecular and Functional Imaging Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Thomas L Clemens
- Department of Orthopaedic Surgery.,Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
| | | | - Ryan C Riddle
- Department of Orthopaedic Surgery.,Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
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27
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Lv S, Qiu X, Li J, Liang J, Li W, Zhang C, Zhang ZN, Luan B. Glucagon-induced extracellular cAMP regulates hepatic lipid metabolism. J Endocrinol 2017; 234:73-87. [PMID: 28515141 DOI: 10.1530/joe-16-0649] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 01/07/2023]
Abstract
Hormonal signals help to maintain glucose and lipid homeostasis in the liver during the periods of fasting. Glucagon, a pancreas-derived hormone induced by fasting, promotes gluconeogenesis through induction of intracellular cAMP production. Glucagon also stimulates hepatic fatty acid oxidation but the underlying mechanism is poorly characterized. Here we report that following the acute induction of gluconeogenic genes Glucose 6 phosphatase (G6Pase) and Phosphoenolpyruvate carboxykinase (Pepck) expression through cAMP-response element-binding protein (CREB), glucagon triggers a second delayed phase of fatty acid oxidation genes Acyl-coenzyme A oxidase (Aox) and Carnitine palmitoyltransferase 1a (Cpt1a) expression via extracellular cAMP. Increase in extracellular cAMP promotes PPARα activity through direct phosphorylation by AMP-activated protein kinase (AMPK), while inhibition of cAMP efflux greatly attenuates Aox and Cpt1a expression. Importantly, cAMP injection improves lipid homeostasis in fasted mice and obese mice, while inhibition of cAMP efflux deteriorates hepatic steatosis in fasted mice. Collectively, our results demonstrate the vital role of glucagon-stimulated extracellular cAMP in the regulation of hepatic lipid metabolism through AMPK-mediated PPARα activation. Therefore, strategies to improve cAMP efflux could serve as potential new tools to prevent obesity-associated hepatic steatosis.
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Affiliation(s)
- Sihan Lv
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xinchen Qiu
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jian Li
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jinye Liang
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Weida Li
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhen-Ning Zhang
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bing Luan
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
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28
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Avila DV, Barker DF, Zhang J, McClain CJ, Barve S, Gobejishvili L. Dysregulation of hepatic cAMP levels via altered Pde4b expression plays a critical role in alcohol-induced steatosis. J Pathol 2017; 240:96-107. [PMID: 27287961 DOI: 10.1002/path.4760] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/06/2016] [Accepted: 05/31/2016] [Indexed: 12/15/2022]
Abstract
Alcohol-induced hepatic steatosis is a significant risk factor for progressive liver disease. Cyclic adenosine monophosphate (cAMP) signalling has been shown to significantly regulate lipid metabolism; however, the role of altered cAMP homeostasis in alcohol-mediated hepatic steatosis has never been studied. Our previous work demonstrated that increased expression of hepatic phosphodiesterase 4 (Pde4), which specifically hydrolyses and decreases cAMP levels, plays a pathogenic role in the development of liver inflammation/injury. The aim of this study was to examine the role of PDE4 in alcohol-induced hepatic steatosis. C57BL/6 wild-type and Pde4b knockout (Pde4b(-/-) ) mice were pair-fed control or ethanol liquid diets. One group of wild-type mice received rolipram, a PDE4-specific inhibitor, during alcohol feeding. We demonstrate for the first time that an early increase in PDE4 enzyme expression and a resultant decrease in hepatic cAMP levels are associated with the significant reduction in carnitine palmitoyltransferase 1A (Cpt1a) expression. Notably, alcohol-fed (AF) Pde4b(-/-) mice and AF wild-type mice treated with rolipram had significantly lower hepatic free fatty acid content compared with AF wild-type mice. Importantly, PDE4 inhibition in alcohol-fed mice prevented the decrease in hepatic Cpt1a expression via the Pparα/Sirt1/Pgc1α pathway. These results demonstrate that the alcohol- induced increase in hepatic Pde4, specifically Pde4b expression, and compromised cAMP signalling predispose the liver to impaired fatty acid oxidation and the development of steatosis. Moreover, these data also suggest that hepatic PDE4 may be a clinically relevant therapeutic target for the treatment of alcohol-induced hepatic steatosis. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Diana V Avila
- Department of Pharmacology and Toxicology, University of Louisville Medical Center, Louisville, Kentucky, USA
| | - David F Barker
- Department of Internal Medicine, University of Louisville Medical Center, Louisville, Kentucky, USA
| | - JingWen Zhang
- Department of Internal Medicine, University of Louisville Medical Center, Louisville, Kentucky, USA
| | - Craig J McClain
- Department of Pharmacology and Toxicology, University of Louisville Medical Center, Louisville, Kentucky, USA.,Department of Internal Medicine, University of Louisville Medical Center, Louisville, Kentucky, USA.,Robley Rex VA Medical Center, Louisville, Kentucky, USA
| | - Shirish Barve
- Department of Pharmacology and Toxicology, University of Louisville Medical Center, Louisville, Kentucky, USA.,Department of Internal Medicine, University of Louisville Medical Center, Louisville, Kentucky, USA
| | - Leila Gobejishvili
- Department of Pharmacology and Toxicology, University of Louisville Medical Center, Louisville, Kentucky, USA.,Department of Internal Medicine, University of Louisville Medical Center, Louisville, Kentucky, USA
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Jun JC, Devera R, Unnikrishnan D, Shin MK, Bevans-Fonti S, Yao Q, Rathore A, Younas H, Halberg N, Scherer PE, Polotsky VY. Adipose HIF-1α causes obesity by suppressing brown adipose tissue thermogenesis. J Mol Med (Berl) 2016; 95:287-297. [PMID: 27738746 DOI: 10.1007/s00109-016-1480-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 09/27/2016] [Accepted: 10/06/2016] [Indexed: 12/18/2022]
Abstract
Hypoxia-inducible factor-1α (HIF-1α) in adipose tissue is known to promote obesity. We hypothesized that HIF-1α interferes with brown fat thermogenesis, thus decreasing energy expenditure. To test this hypothesis, we compared transgenic mice constitutively expressing HIF-1α in adipose tissues (HIF-1α++) at usual temperature (22 °C), where brown fat is somewhat active, or at thermoneutrality (30 °C), where brown fat is minimally active. HIF-1α++ mice or control litter mates were separated into room temperature (22 °C) or thermoneutrality (30 °C) groups. We assessed weight gain, food intake, calorimetry, activity, and oxygen consumption and transcriptional changes in isolated white and brown adipocytes. At 22 °C, HIF-1α++ mice exhibited accelerated weight gain, cold and glucose intolerance, hyperglycemia, and decreased energy expenditure without changes in food intake or activity. These changes were absent or minimal at thermoneutrality. In brown adipocytes of HIF-1α++ mice, oxygen consumption decreased ~50 % in association with reduced mitochondrial content, uncoupling protein 2, and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1α). In conclusion, adipose HIF-1α overexpression inhibits thermogenesis and cellular respiration in brown adipose tissue, promoting obesity in the setting of reduced ambient temperature. KEY MESSAGE Constitutive HIF-1α activation in adipose tissue promotes weight gain in mice. The weight gain is associated with reduced brown adipose tissue function and oxygen consumption. Reduced oxygen consumption may be mediated by reductions in mitochondria.
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Affiliation(s)
- Jonathan C Jun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA.
| | - Ronald Devera
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Dileep Unnikrishnan
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Mi-Kyung Shin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Shannon Bevans-Fonti
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Qiaoling Yao
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Aman Rathore
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Haris Younas
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
| | - Nils Halberg
- Touchstone Diabetes Center, Departments of Internal Medicine and Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Departments of Internal Medicine and Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins, University School of Medicine, 5501 Hopkins Bayview Circle Room 4A30A, Baltimore, MD, 21224, USA
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Vancura P, Wolloscheck T, Baba K, Tosini G, Iuvone PM, Spessert R. Circadian and Dopaminergic Regulation of Fatty Acid Oxidation Pathway Genes in Retina and Photoreceptor Cells. PLoS One 2016; 11:e0164665. [PMID: 27727308 PMCID: PMC5058478 DOI: 10.1371/journal.pone.0164665] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/28/2016] [Indexed: 12/17/2022] Open
Abstract
The energy metabolism of the retina might comply with daily changes in energy demand and is impaired in diabetic retinopathy-one of the most common causes of blindness in Europe and the USA. The aim of this study was to investigate putative adaptation of energy metabolism in healthy and diabetic retina. Hence expression analysis of metabolic pathway genes was performed using quantitative polymerase chain reaction, semi-quantitative western blot and immunohistochemistry. Transcriptional profiling of key enzymes of energy metabolism identified transcripts of mitochondrial fatty acid β-oxidation enzymes, i.e. carnitine palmitoyltransferase-1α (Cpt-1α) and medium chain acyl-CoA dehydrogenase (Acadm) to display daily rhythms with peak values during daytime in preparations of the whole retina and microdissected photoreceptors. The cycling of both enzymes persisted in constant darkness, was dampened in mice deficient for dopamine D4 (D4) receptors and was altered in db/db mice-a model of diabetic retinopathy. The data of the present study are consistent with circadian clock-dependent and dopaminergic regulation of fatty acid oxidation in retina and its putative disturbance in diabetic retina.
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MESH Headings
- Acyl-CoA Dehydrogenase/genetics
- Acyl-CoA Dehydrogenase/metabolism
- Animals
- Carnitine O-Palmitoyltransferase/genetics
- Carnitine O-Palmitoyltransferase/metabolism
- Circadian Rhythm/physiology
- Diabetic Retinopathy/metabolism
- Diabetic Retinopathy/pathology
- Disease Models, Animal
- Dopamine/metabolism
- Energy Metabolism
- Fatty Acids/chemistry
- Fatty Acids/metabolism
- Female
- Male
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Obese
- Microscopy, Fluorescence
- Oxidation-Reduction
- Photoreceptor Cells/metabolism
- Receptor, Melatonin, MT1/deficiency
- Receptor, Melatonin, MT1/genetics
- Receptors, Dopamine D4/deficiency
- Receptors, Dopamine D4/genetics
- Retina/metabolism
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Affiliation(s)
- Patrick Vancura
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Tanja Wolloscheck
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Kenkichi Baba
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - P. Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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31
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Geisler CE, Hepler C, Higgins MR, Renquist BJ. Hepatic adaptations to maintain metabolic homeostasis in response to fasting and refeeding in mice. Nutr Metab (Lond) 2016; 13:62. [PMID: 27708682 PMCID: PMC5037643 DOI: 10.1186/s12986-016-0122-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 09/15/2016] [Indexed: 12/26/2022] Open
Abstract
Background The increased incidence of obesity and associated metabolic diseases has driven research focused on genetically or pharmacologically alleviating metabolic dysfunction. These studies employ a range of fasting-refeeding models including 4–24 h fasts, “overnight” fasts, or meal feeding. Still, we lack literature that describes the physiologically relevant adaptations that accompany changes in the duration of fasting and re-feeding. Since the liver is central to whole body metabolic homeostasis, we investigated the timing of the fast-induced shift toward glycogenolysis, gluconeogenesis, and ketogenesis and the meal-induced switch toward glycogenesis and away from ketogenesis. Methods Twelve to fourteen week old male C57BL/6J mice were fasted for 0, 4, 8, 12, or 16 h and sacrificed 4 h after lights on. In a second study, designed to understand the response to a meal, we gave fasted mice access to feed for 1 or 2 h before sacrifice. We analyzed the data using mixed model analysis of variance. Results Fasting initiated robust metabolic shifts, evidenced by changes in serum glucose, non-esterified fatty acids (NEFAs), triacylglycerol, and β-OH butyrate, as well as, liver triacylglycerol, non-esterified fatty acid, and glycogen content. Glycogenolysis is the primary source to maintain serum glucose during the first 8 h of fasting, while de novo gluconeogenesis is the primary source thereafter. The increase in serum β-OH butyrate results from increased enzymatic capacity for fatty acid flux through β-oxidation and shunting of acetyl-CoA toward ketone body synthesis (increased CPT1 (Carnitine Palmitoyltransferase 1) and HMGCS2 (3-Hydroxy-3-Methylglutaryl-CoA Synthase 2) expression, respectively). In opposition to the relatively slow metabolic adaptation to fasting, feeding of a meal results in rapid metabolic changes including full depression of serum β-OH butyrate and NEFAs within an hour. Conclusions Herein, we provide a detailed description of timing of the metabolic adaptations in response to fasting and re-feeding to inform study design in experiments of metabolic homeostasis. Since fasting and obesity are both characterized by elevated adipose tissue lipolysis, hepatic lipid accumulation, ketogenesis, and gluconeogenesis, understanding the drivers behind the metabolic shift from the fasted to the fed state may provide targets to limit aberrant gluconeogenesis and ketogenesis in obesity.
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Affiliation(s)
- C E Geisler
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA
| | - C Hepler
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75235 USA
| | - M R Higgins
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA
| | - B J Renquist
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 4101 North Campbell Avenue, Tucson, AZ 85719 USA
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32
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Tan Z, Luo X, Xiao L, Tang M, Bode AM, Dong Z, Cao Y. The Role of PGC1α in Cancer Metabolism and its Therapeutic Implications. Mol Cancer Ther 2016; 15:774-82. [DOI: 10.1158/1535-7163.mct-15-0621] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/29/2016] [Indexed: 11/16/2022]
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Chen Y, Gall MG, Zhang H, Keane FM, McCaughan GW, Yu DMT, Gorrell MD. Dipeptidyl peptidase 9 enzymatic activity influences the expression of neonatal metabolic genes. Exp Cell Res 2016; 342:72-82. [PMID: 26930324 DOI: 10.1016/j.yexcr.2016.02.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/25/2016] [Accepted: 02/26/2016] [Indexed: 02/07/2023]
Abstract
The success of dipeptidyl peptidase 4 (DPP4) inhibition as a type 2 diabetes therapy has encouraged deeper examination of the post-proline DPP enzymes. DPP9 has been implicated in immunoregulation, disease pathogenesis and metabolism. The DPP9 enzyme-inactive (Dpp9 gene knock-in; Dpp9 gki) mouse displays neonatal lethality, suggesting that DPP9 enzyme activity is essential in neonatal development. Here we present gene expression patterns in these Dpp9 gki neonatal mice. Taqman PCR arrays and sequential qPCR assays on neonatal liver and gut revealed differential expression of genes involved in cell growth, innate immunity and metabolic pathways including long-chain-fatty-acid uptake and esterification, long-chain fatty acyl-CoA binding, trafficking and transport into mitochondria, lipoprotein metabolism, adipokine transport and gluconeogenesis in the Dpp9 gki mice compared to wild type. In a liver cell line, Dpp9 knockdown increased AMP-activated protein kinase phosphorylation, which suggests a potential mechanism. DPP9 protein levels in liver cells were altered by treatment with EGF, HGF, insulin or palmitate, suggesting potential natural DPP9 regulators. These gene expression analyses of a mouse strain deficient in DPP9 enzyme activity show, for the first time, that DPP9 enzyme activity regulates metabolic pathways in neonatal liver and gut.
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Affiliation(s)
- Yiqian Chen
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Margaret G Gall
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Hui Zhang
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Fiona M Keane
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Geoffrey W McCaughan
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Denise M T Yu
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Mark D Gorrell
- Centenary Institute and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.
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Prastowo S, Amin A, Rings F, Held E, Wondim DS, Gad A, Neuhoff C, Tholen E, Looft C, Schellander K, Tesfaye D, Hoelker M. Fateful triad of reactive oxygen species, mitochondrial dysfunction and lipid accumulation is associated with expression outline of the AMP-activated protein kinase pathway in bovine blastocysts. Reprod Fertil Dev 2016; 29:RD15319. [PMID: 26907741 DOI: 10.1071/rd15319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 12/17/2015] [Indexed: 12/11/2022] Open
Abstract
Low cryotolerance is considered as the major drawback of in vitro-produced bovine embryos and is frequently associated with a triad encompassing increased cytoplasmic lipid accumulation, enhanced levels of reactive oxygen species (ROS) and mitochondrial dysfunction. The aim of the present study was to explore the role of the AMP-activated protein kinase (AMPK) pathway in the process resulting such phenotypes. Comparative analysis under different environmental conditions revealed downregulation of AMP-activated protein kinase cytalytic subunit 1alpha (AMPKA1), peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1A) and carnitine palmitoyltransferase 1 (CPT1) genes and upregulation of acetyl-CoA carboxylase α (ACC). In contrast, the presence of fatty acids within the culture medium resulted in a distinct molecular profile in the embryo associated with enhanced levels of ROS, mitochondrial dysfunction and elevated lipid accumulation in bovine embryos. Because AMPKA1 regulates PGC1A, CPT1 and ACC, the results of the present study reveal that AMPK in active its form is the key enzyme promoting lipolysis. Because AMPK1 activity is, in turn, controlled by the AMP : ATP ratio, it is possible to speculate that excessive uptake of exogenous free fatty acids could increase cellular ATP levels as a result of the disturbed β-oxidation of these external fatty acids and could therefore bypass that molecular feedback mechanism. Subsequently, this condition would cause enhanced generation of ROS, which negatively affect mitochondrial activity. Both enhanced generation of ROS and low mitochondrial activity are suggested to enhance the accumulation of lipids in bovine embryos.
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35
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Deng X, Wang J, Jiao L, Utaipan T, Tuma-Kellner S, Schmitz G, Liebisch G, Stremmel W, Chamulitrat W. iPLA2β deficiency attenuates obesity and hepatic steatosis in ob/ob mice through hepatic fatty-acyl phospholipid remodeling. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:449-61. [PMID: 26873633 DOI: 10.1016/j.bbalip.2016.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/01/2016] [Accepted: 02/06/2016] [Indexed: 01/12/2023]
Abstract
PLA2G6 or GVIA calcium-independent PLA2 (iPLA2β) is identified as one of the NAFLD modifier genes in humans, and thought to be a target for NAFLD therapy. iPLA2β is known to play a house-keeping role in phospholipid metabolism and remodeling. However, its role in NAFLD pathogenesis has not been supported by results obtained from high-fat feeding of iPLA2β-null (PKO) mice. Unlike livers of human NAFLD and genetically obese rodents, fatty liver induced by high-fat diet is not associated with depletion of hepatic phospholipids. We therefore tested whether iPLA2β could regulate obesity and hepatic steatosis in leptin-deficient mice by cross-breeding PKO with ob/ob mice to generate ob/ob-PKO mice. Here we observed an improvement in ob/ob-PKO mice with significant reduction in serum enzymes, lipids, glucose, insulin as well as improved glucose tolerance, and reduction in islet hyperplasia. The improvement in hepatic steatosis measured by liver triglycerides, fatty acids and cholesterol esters was associated with decreased expression of PPARγ and de novo lipogenesis genes, and the reversal of β-oxidation gene expression. Notably, ob/ob livers contained depleted levels of lysophospholipids and phospholipids, and iPLA2β deficiency in ob/ob-PKO livers lowers the former, but replenished the latter particularly phosphatidylethanolamine (PE) and phosphatidylcholine (PC) that contained arachidonic (AA) and docosahexaenoic (DHA) acids. Compared with WT livers, PKO livers also contained increased PE and PC containing AA and DHA. Thus, iPLA2β deficiency protected against obesity and ob/ob fatty liver which was associated with hepatic fatty-acyl phospholipid remodeling. Our results support the deleterious role of iPLA2β in severe obesity associated NAFLD.
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Affiliation(s)
- Xiuling Deng
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China
| | - Jiliang Wang
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Li Jiao
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Tanyarath Utaipan
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Wolfgang Stremmel
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.
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Wahlang B, Prough RA, Falkner KC, Hardesty JE, Song M, Clair HB, Clark BJ, States JC, Arteel GE, Cave MC. Polychlorinated Biphenyl-Xenobiotic Nuclear Receptor Interactions Regulate Energy Metabolism, Behavior, and Inflammation in Non-alcoholic-Steatohepatitis. Toxicol Sci 2015; 149:396-410. [PMID: 26612838 DOI: 10.1093/toxsci/kfv250] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are environmental pollutants associated with non-alcoholic-steatohepatitis (NASH), diabetes, and obesity. We previously demonstrated that the PCB mixture, Aroclor 1260, induced steatohepatitis and activated nuclear receptors in a diet-induced obesity mouse model. This study aims to evaluate PCB interactions with the pregnane-xenobiotic receptor (Pxr: Nr1i2) and constitutive androstane receptor (Car: Nr1i3) in NASH. Wild type C57Bl/6 (WT), Pxr(-/-) and Car(-/-) mice were fed the high fat diet (42% milk fat) and exposed to a single dose of Aroclor 1260 (20 mg/kg) in this 12-week study. Metabolic phenotyping and analysis of serum, liver, and adipose was performed. Steatohepatitis was pathologically similar in all Aroclor-exposed groups, while Pxr(-/-) mice displayed higher basal pro-inflammatory cytokine levels. Pxr repressed Car expression as evident by increased basal Car/Cyp2b10 expression in Pxr(-/-) mice. Both Pxr(-/-) and Car(-/-) mice showed decreased basal respiratory exchange rate (RER) consistent with preferential lipid metabolism. Aroclor increased RER and carbohydrate metabolism, associated with increased light cycle activity in both knockouts, and decreased food consumption in the Car(-/-) mice. Aroclor exposure improved insulin sensitivity in WT mice but not glucose tolerance. The Aroclor-exposed, Pxr(-/-) mice displayed increased gluconeogenic gene expression. Lipid-oxidative gene expression was higher in WT and Pxr(-/-) mice although RER was not changed, suggesting PCB-mediated mitochondrial dysfunction. Therefore, Pxr and Car regulated inflammation, behavior, and energy metabolism in PCB-mediated NASH. Future studies should address the 'off-target' effects of PCBs in steatohepatitis.
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Affiliation(s)
| | | | - K Cameron Falkner
- Department of Medicine Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202
| | | | - Ming Song
- Department of Medicine Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202
| | | | | | | | | | - Matthew C Cave
- *Department of Pharmacology and Toxicology; Department of Biochemistry and Molecular Genetics; Department of Medicine Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202; The Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206; and The KentuckyOne Health Jewish Hospital Liver Transplant Program, Louisville, KY 40202
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Chan YL, Saad S, Simar D, Oliver B, McGrath K, Reyk DV, Bertrand PP, Gorrie C, Pollock C, Chen H. Short term exendin-4 treatment reduces markers of metabolic disorders in female offspring of obese rat dams. Int J Dev Neurosci 2015; 46:67-75. [PMID: 26287659 DOI: 10.1016/j.ijdevneu.2015.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/05/2015] [Accepted: 05/14/2015] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVES Maternal obesity imposes significant health risks in the offspring including diabetes and dyslipidemia. We previously showed that the hypoglycaemic agent exendin-4 (Ex-4) administered from weaning can reverse the maternal impact of 'transmitted disorders' in such offspring. However daily injection for six-weeks was required and the beneficial effect may lapse upon drug withdrawal. This study aimed to investigate whether short term Ex-4 treatment during suckling period in a rodent model can reverse transmitted metabolic disorders due to maternal obesity. METHODS Maternal obesity was induced in female Sprague Dawley rats by high-fat diet feeding for 6 weeks, throughout gestation and lactation. Female offspring were treated with Ex-4 (5μg/kg/day) between postnatal day (P) 4 and 14. Female offspring were harvested at weaning (P20). Lipid and glucose metabolic markers were measured in the liver and fat. Appetite regulators were measured in the plasma and hypothalamus. RESULTS Maternal obesity significantly increased body weight, fat mass, and liver weight in the offspring. There was an associated inhibition of peroxisomal proliferator activated receptor gamma coactivator 1α (PGC1α), increased fatty acid synthase (FASN) expression in the liver, and reduced adipocyte triglyceride lipase (ATGL) expression. It also increased the plasma gut hormone ghrelin and reduced glucagon-like peptide-1. Ex-4 treatment partially reversed the maternal impact on adiposity and impaired lipid metabolism in the offspring, with increased liver PGC1α and inhibition of FASN mRNA expression. Ex-4 treatment also increased the expression of a novel fat depletion gene a2-zinc-glycoprotein 1 in the fat tissue. CONCLUSION Short term Ex-4 treatment during the suckling period significantly improved the metabolic profile in the offspring from the obese mothers at weaning. Long-term studies are needed to follow such offspring to adulthood to examine the sustained effects of Ex-4 in preventing the development of metabolic disease.
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Affiliation(s)
- Yik Lung Chan
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia
| | - Sonia Saad
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia; Department of Medicine, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW 2065, Australia
| | - David Simar
- Inflammation and Infection Research, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Brian Oliver
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia
| | - Kristine McGrath
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia
| | - David van Reyk
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia
| | - Paul P Bertrand
- School of Medical Sciences, RMIT University, VIC, 3001, Australia
| | - Cathy Gorrie
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia
| | - Carol Pollock
- Department of Medicine, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW 2065, Australia
| | - Hui Chen
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW 2007, Australia.
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Garvey SM, Russ DW, Skelding MB, Dugle JE, Edens NK. Molecular and metabolomic effects of voluntary running wheel activity on skeletal muscle in late middle-aged rats. Physiol Rep 2015; 3:3/2/e12319. [PMID: 25716928 PMCID: PMC4393218 DOI: 10.14814/phy2.12319] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We examined the molecular and metabolomic effects of voluntary running wheel activity in late middle-aged male Sprague Dawley rats (16–17 months). Rats were assigned either continuous voluntary running wheel access for 8 weeks (RW+) or cage-matched without running wheel access (RW−). The 9 RW+ rats averaged 83 m/day (range: 8–163 m), yet exhibited both 84% reduced individual body weight gain (4.3 g vs. 26.3 g, P = 0.02) and 6.5% reduced individual average daily food intake (20.6 g vs. 22.0 g, P = 0.09) over the 8 weeks. Hindlimb muscles were harvested following an overnight fast. Muscle weights and myofiber cross-sectional area showed no difference between groups. Western blots of gastrocnemius muscle lysates with a panel of antibodies suggest that running wheel activity improved oxidative metabolism (53% increase in PGC1α, P = 0.03), increased autophagy (36% increase in LC3B-II/-I ratio, P = 0.03), and modulated growth signaling (26% increase in myostatin, P = 0.04). RW+ muscle also showed 43% increased glycogen phosphorylase expression (P = 0.04) and 45% increased glycogen content (P = 0.04). Metabolomic profiling of plantaris and soleus muscles indicated that even low-volume voluntary running wheel activity is associated with decreases in many long-chain fatty acids (e.g., palmitoleate, myristoleate, and eicosatrienoate) relative to RW− rats. Relative increases in acylcarnitines and acyl glycerophospholipids were also observed in RW+ plantaris. These data establish that even modest amounts of physical activity during late middle-age promote extensive metabolic remodeling of skeletal muscle.
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Affiliation(s)
| | - David W Russ
- Division of Physical Therapy, Ohio University, Athens, Ohio, USA Ohio Musculoskeletal & Neurological Institute (OMNI), Heritage College of Osteopathic Medicine, Athens, Ohio, USA
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Zou X, Yan C, Shi Y, Cao K, Xu J, Wang X, Chen C, Luo C, Li Y, Gao J, Pang W, Zhao J, Zhao F, Li H, Zheng A, Sun W, Long J, Szeto IMY, Zhao Y, Dong Z, Zhang P, Wang J, Lu W, Zhang Y, Liu J, Feng Z. Mitochondrial dysfunction in obesity-associated nonalcoholic fatty liver disease: the protective effects of pomegranate with its active component punicalagin. Antioxid Redox Signal 2014; 21:1557-70. [PMID: 24393106 PMCID: PMC4175030 DOI: 10.1089/ars.2013.5538] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AIMS Punicalagin (PU) is one of the major ellagitannins found in the pomegranate (Punica granatum), which is a popular fruit with several health benefits. So far, no studies have evaluated the effects of PU on nonalcoholic fatty liver disease (NAFLD). Our work aims at studying the effect of PU-enriched pomegranate extract (PE) on high fat diet (HFD)-induced NAFLD. RESULTS PE administration at a dosage of 150 mg/kg/day significantly inhibited HFD-induced hyperlipidemia and hepatic lipid deposition. As major contributors to NAFLD, increased expression of pro-inflammatory cytokines such as tumor necrosis factor-alpha, interleukins 1, 4, and 6 as well as augmented oxidative stress in hepatocytes followed by nuclear factor (erythroid-derived-2)-like 2 (Nrf2) activation were normalized through PE supplementation. In addition, PE treatment reduced uncoupling protein 2 (UCP2) expression, restored ATP content, suppressed mitochondrial protein oxidation, and improved mitochondrial complex activity in the liver. In contrast, mitochondrial content was not affected despite increased peroxisomal proliferator-activated receptor-gamma coactivator-1α (PGC-1α) and elevated expression of genes related to mitochondrial beta-oxidation after PE treatment. Finally, PU was identified as the predominant active component of PE with regard to the lowering of triglyceride and cholesterol content in HepG2 cells, and both PU- and PE-protected cells from palmitate induced mitochondrial dysfunction and insulin resistance. INNOVATION Our work presents the beneficial effects of PE on obesity-associated NAFLD and multiple risk factors. PU was proposed to be the major active component. CONCLUSIONS By promoting mitochondrial function, eliminating oxidative stress and inflammation, PU may be a useful nutrient for the treatment of NAFLD.
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Affiliation(s)
- Xuan Zou
- 1 The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Frontier Institute of Science and Technology, Xi'an Jiaotong University , Xi'an, China
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McCarty MF, DiNicolantonio JJ. The cardiometabolic benefits of glycine: Is glycine an 'antidote' to dietary fructose? Open Heart 2014; 1:e000103. [PMID: 25332814 PMCID: PMC4195924 DOI: 10.1136/openhrt-2014-000103] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/26/2014] [Indexed: 02/06/2023] Open
Affiliation(s)
| | - James J DiNicolantonio
- Department of Preventive Cardiology , Saint Luke's Mid America Heart Institute , Kansas City, Missouri , USA
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Takeshita Y, Takamura T, Honda M, Kita Y, Zen Y, Kato KI, Misu H, Ota T, Nakamura M, Yamada K, Sunagozaka H, Arai K, Yamashita T, Mizukoshi E, Kaneko S. The effects of ezetimibe on non-alcoholic fatty liver disease and glucose metabolism: a randomised controlled trial. Diabetologia 2014; 57:878-90. [PMID: 24407920 DOI: 10.1007/s00125-013-3149-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/15/2013] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS The cholesterol absorption inhibitor ezetimibe has been shown to ameliorate non-alcoholic fatty liver disease (NAFLD) pathology in a single-armed clinical study and in experimental animal models. In this study, we investigated the efficacy of ezetimibe on NAFLD pathology in an open-label randomised controlled clinical trial. METHODS We had planned to enrol 80 patients in the trial, as we had estimated that, with this sample size, the study would have 90% power. The study intervention and enrolment were discontinued because of the higher proportion of adverse events (significant elevation in HbA(1c)) in the ezetimibe group than in the control group. Thirty-two patients with NAFLD were enrolled and randomised (allocation by computer program). Ezetimibe (10 mg/day) was given to 17 patients with NAFLD for 6 months. The primary endpoint was change in serum aminotransferase level. Secondary outcomes were change in liver histology (12 control and 16 ezetimibe patients), insulin sensitivity including a hyperinsulinaemic-euglycaemic clamp study (ten control and 13 ezetimibe patients) and hepatic fatty acid composition (six control and nine ezetimibe patients). Hepatic gene expression profiling was completed in 15 patients using an Affymetrix gene chip. Patients and the physician in charge knew to which group the patient had been allocated, but people carrying out measurements or examinations were blinded to group. RESULTS Serum total cholesterol was significantly decreased in the ezetimibe group. The fibrosis stage and ballooning score were also significantly improved with ezetimibe treatment. However, ezetimibe treatment significantly increased HbA1c and was associated with a significant increase in hepatic long-chain fatty acids. Hepatic gene expression analysis showed coordinate downregulation of genes involved in skeletal muscle development and cell adhesion molecules in the ezetimibe treatment group, suggesting a suppression of stellate cell development into myofibroblasts. Genes involved in the L-carnitine pathway were coordinately downregulated by ezetimibe treatment and those in the steroid metabolism pathway upregulated, suggestive of impaired oxidation of long-chain fatty acids. CONCLUSIONS/INTERPRETATION Ezetimibe improved hepatic fibrosis but increased hepatic long-chain fatty acids and HbA1c in patients with NAFLD. These findings shed light on previously unrecognised actions of ezetimibe that should be examined further in future studies. TRIAL REGISTRATION University Hospital Medical Information Network (UMIN) Clinical Trials Registry UMIN000005250. FUNDING The study was funded by grants-in-aid from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and research grants from MSD.
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Affiliation(s)
- Yumie Takeshita
- Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
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Liquid fructose downregulates Sirt1 expression and activity and impairs the oxidation of fatty acids in rat and human liver cells. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:514-24. [DOI: 10.1016/j.bbalip.2014.01.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/13/2013] [Accepted: 01/06/2014] [Indexed: 02/06/2023]
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Arensdorf AM, Dezwaan McCabe D, Kaufman RJ, Rutkowski DT. Temporal clustering of gene expression links the metabolic transcription factor HNF4α to the ER stress-dependent gene regulatory network. Front Genet 2013; 4:188. [PMID: 24069029 PMCID: PMC3781334 DOI: 10.3389/fgene.2013.00188] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 09/03/2013] [Indexed: 11/13/2022] Open
Abstract
The unfolded protein response (UPR) responds to disruption of endoplasmic reticulum (ER) function by initiating signaling cascades that ultimately culminate in extensive transcriptional regulation. Classically, this regulation includes genes encoding ER chaperones, ER-associated degradation factors, and others involved in secretory protein folding and processing, and is carried out by the transcriptional activators that are produced as a consequence of UPR activation. However, up to half of the mRNAs regulated by ER stress are downregulated rather than upregulated, and the mechanisms linking ER stress and UPR activation to mRNA suppression are poorly understood. To begin to address this issue, we used a "bottom-up" approach to study the metabolic gene regulatory network controlled by the UPR in the liver, because ER stress in the liver leads to lipid accumulation, and fatty liver disease is the most common liver disease in the western world. qRT-PCR profiling of mouse liver mRNAs during ER stress revealed that suppression of the transcriptional regulators C/EBPα, PPARα, and PGC-1α preceded lipid accumulation, and was then followed by suppression of mRNAs encoding key enzymes involved in fatty acid oxidation and lipoprotein biogenesis and transport. Mice lacking the ER stress sensor ATF6α, which experience persistent ER stress and profound lipid accumulation during challenge, were then used as the basis for a functional genomics approach that allowed genes to be grouped into distinct expression profiles. This clustering predicted that ER stress would suppress the activity of the metabolic transcriptional regulator HNF4α-a finding subsequently confirmed by chromatin immunopreciptation at the Cebpa and Pgc1a promoters. Our results establish a framework for hepatic gene regulation during ER stress and suggest that HNF4α occupies the apex of that framework. They also provide a unique resource for the community to further explore the temporal regulation of gene expression during ER stress in vivo.
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Affiliation(s)
- Angela M Arensdorf
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine Iowa City, IA, USA
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The protein level of PGC-1α, a key metabolic regulator, is controlled by NADH-NQO1. Mol Cell Biol 2013; 33:2603-13. [PMID: 23648480 DOI: 10.1128/mcb.01672-12] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PGC-1α is a key transcription coactivator regulating energy metabolism in a tissue-specific manner. PGC-1α expression is tightly regulated, it is a highly labile protein, and it interacts with various proteins--the known attributes of intrinsically disordered proteins (IDPs). In this study, we characterize PGC-1α as an IDP and demonstrate that it is susceptible to 20S proteasomal degradation by default. We further demonstrate that PGC-1α degradation is inhibited by NQO1, a 20S gatekeeper protein. NQO1 binds and protects PGC-1α from degradation in an NADH-dependent manner. Using different cellular physiological settings, we also demonstrate that NQO1-mediated PGC-1α protection plays an important role in controlling both basal and physiologically induced PGC-1α protein level and activity. Our findings link NQO1, a cellular redox sensor, to the metabolite-sensing network that tunes PGC-1α expression and activity in regulating energy metabolism.
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Yu K, Shu G, Yuan F, Zhu X, Gao P, Wang S, Wang L, Xi Q, Zhang S, Zhang Y, Li Y, Wu T, Yuan L, Jiang Q. Fatty acid and transcriptome profiling of longissimus dorsi muscles between pig breeds differing in meat quality. Int J Biol Sci 2013; 9:108-18. [PMID: 23355796 PMCID: PMC3555150 DOI: 10.7150/ijbs.5306] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 12/24/2012] [Indexed: 11/09/2022] Open
Abstract
Fat and lean pig breeds show obvious differences in meat quality characteristics including the fatty acid composition of muscle. However, the molecular mechanism underlying these phenotypes differences remains unknown. This study compared meat quality traits between Lantang (a Chinese indigenous breed) and Landrace (a typical lean breed). The Lantang pigs showed higher L* values and intramuscular fat content, lower pH45min, pH24h and shear force in longissimus dorsi (LD) muscle than Landrace (P < 0.05). Fatty acid analysis demonstrated the lower monounsaturated fatty acids (MUFA) and higher polyunsaturated fatty acids (PUFA) percentage in Lantang LD than that in Landrace LD (P < 0.05). To further identify candidate genes for fatty acid composition, the transcriptome of LD muscle from the two breeds were measured by microarrays. There were 586 transcripts differentially expressed, of which 267 transcripts were highly expressed in Lantang pigs. After the validation by real-time quantitative PCR, 13 genes were determined as candidate genes for fatty acid composition of muscle, including Stearoyl-CoA desaturase (SCD). Then, a SCD over-expression plasmid was transfected into C2C12 cells to reveal the effect of SCD on the fatty acid composition in vitro. The results showed that SCD over-expression significantly increased PUFA proportion, while reduced that of saturated fatty acids (SFA) in C2C12 cells (P < 0.05). In summary, this study compared the differences of fatty acid composition and transcriptome in two breeds differing in meat quality, and further identified the novel role of SCD in the regulation of PUFA deposition.
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Affiliation(s)
- Kaifan Yu
- College of Animal Science, South China Agricultural University, Guangdong province, Guangzhou 510642, China
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Budick-Harmelin N, Anavi S, Madar Z, Tirosh O. Fatty acids-stress attenuates gluconeogenesis induction and glucose production in primary hepatocytes. Lipids Health Dis 2012; 11:66. [PMID: 22676303 PMCID: PMC3391994 DOI: 10.1186/1476-511x-11-66] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 06/07/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Hepatic gluconeogenesis tightly controls blood glucose levels in healthy individuals, yet disorders of fatty acids (FAs) oxidation are characterized by hypoglycemia. We studied the ability of free-FAs to directly inhibit gluconeogenesis, as a novel mechanism that elucidates the hypoglycemic effect of FAs oxidation defects. METHODS Primary rat hepatocytes were pre-treated with FAs prior to gluconeogenic stimuli with glucagon or dexamethasone and cAMP. RESULTS Pre-treatment with 1 mM FAs (mixture of 2:1 oleate:palmitate) for 1 hour prior to gluconeogenic induction, significantly decreases the induced expression of the gluconeogenic genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6pase) as well as the induced glucose production by the cells. The inhibitory effect of FAs upon gluconeogenesis is abolished when pre-treatment is elongated to 18 hours, allowing clearance of FAs into triglycerides by the cells. Replacement of palmitate with the non-metabolic fatty acid 2-bromopalmitate inhibits esterification of FAs into triglycerides. Accordingly, the increased exposure to unesterified-FAs allows their inhibitory effect to be extended even when pre-treatment is elongated to 18 hours. Similar changes were caused by FAs to the induction of peroxisome-proliferator-activated receptor-γ coactivator 1α (PGC1α) expression, indicating this transcriptional coactivator as the mediating link of the effect. This inhibitory effect of FAs upon gluconeogenic induction is shown to involve reduced activation of cAMP response element-binding (CREB) transcription factor. CONCLUSIONS The present results demonstrate that free-FAs directly inhibit the induced gluconeogenic response in hepatocytes. Hence, high levels of free-FAs may attenuate hepatic gluconeogenesis, and liver glucose output.
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Affiliation(s)
- Noga Budick-Harmelin
- School of Nutritional Sciences, Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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Cao Z, Jin L, Liu Y, Jiang Z, Zhang D. Crosslinkable fluorinated hyperbranched polyimide for thermo-optic switches with high thermal stability. J Appl Polym Sci 2012. [DOI: 10.1002/app.37846] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Birds and longevity: does flight driven aerobicity provide an oxidative sink? Ageing Res Rev 2012; 11:242-53. [PMID: 22198369 DOI: 10.1016/j.arr.2011.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/28/2011] [Accepted: 12/06/2011] [Indexed: 12/25/2022]
Abstract
Birds generally age slower and live longer than similar sized mammals. For birds this occurs despite elevated blood glucose levels that for mammals would in part define them as diabetic. However these data were acquired in respiration states that have little resemblance to conditions in healthy tissues and mitochondrial RS production is probably minimal in healthy animals. Indeed mitochondria probably act as net consumers rather than producers of RS. Here we propose that (1) if mitochondria are antioxidant systems, the greater mitochondrial mass in athletic species, such as birds, is advantageous as it should provide a substantial sink for RS. (2) The intense drive for aerobic performance and decreased body density to facilitate flight may explain the relative insensitivity of birds to insulin, as well as depressed insulin levels and apparent sensitization to glucagon. Glucagon also associates with the sirtuin protein family, most of which are associated with caloric restriction regulated pathways, mitochondrial biogenesis and life span extension. (3) We note that telomeres, which appear to be unusually long in birds, bind Sirtuins 2 and 4 and therefore may stabilize and protect nuclear DNA. Ultimately these flight driven responses may suppress somatic growth and protect DNA from oxidative damage that would otherwise lead to ageing and non-viral cancers.
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Staudinger JL, Xu C, Biswas A, Mani S. Post-translational modification of pregnane x receptor. Pharmacol Res 2011; 64:4-10. [PMID: 21397695 DOI: 10.1016/j.phrs.2011.02.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 02/24/2011] [Accepted: 02/27/2011] [Indexed: 01/07/2023]
Abstract
Pregnane x receptor (PXR, NR1I2) was originally characterized as a broad spectrum entero-hepatic xenobiotic 'sensor' and master-regulator of drug inducible gene expression. A compelling description of ligand-mediated gene activation has been unveiled in the last decade that firmly establishes this receptor's central role in the metabolism and transport of xenobiotics in mammals. Interestingly, pharmacotherapy with potent PXR ligands produces several profound side effects including decreased capacities for gluconeogenesis, lipid metabolism, and inflammation; likely due to PXR-mediated repression of gene expression programs underlying these pivotal physiological functions. An integrated model is emerging that reveals a sophisticated interplay between ligand binding and the ubiquitylation, phosphorylation, SUMOylation, and acetylation status of this important nuclear receptor protein. These discoveries point to a key role for the post-translational modification of PXR in the selective suppression of gene expression, and open the door to the study of completely new modes of regulation of the biological activity of PXR.
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Affiliation(s)
- Jeff L Staudinger
- Pharmacology and Toxicology, University of Kansas, 1251 Wescoe Hall Dr., 5038a Malott Hall, Lawrence, KA 66045, USA.
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Vilà L, Roglans N, Perna V, Sánchez RM, Vázquez-Carrera M, Alegret M, Laguna JC. Liver AMP/ATP ratio and fructokinase expression are related to gender differences in AMPK activity and glucose intolerance in rats ingesting liquid fructose. J Nutr Biochem 2010; 22:741-51. [PMID: 21115336 DOI: 10.1016/j.jnutbio.2010.06.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 04/30/2010] [Accepted: 06/01/2010] [Indexed: 12/21/2022]
Abstract
Women, but not men, show an association between fructose consumption and an increased risk of Type 2 diabetes mellitus. As rats are considered a model for human fructose metabolism, we sought to determine whether such a gender-related difference is present in Sprague-Dawley rats and to analyze the molecular mechanism behind. Male and female Sprague-Dawley rats had free access to water or to a 10% w/v fructose solution for 14 days. Plasma analytes, liver triglycerides and enzyme activities and the expression of enzymes and transcription factors related to fatty acid metabolism, insulin signaling and glucose tolerance were determined. Fructose-fed rats had hypertriglyceridemia, steatosis and reduced fatty acid oxidation activity, although the metabolic pattern of fructose-fed female rats was different to that observed for male rats. Fructose-fed female, but not male rats, showed no change in plasma leptin; they had hyperinsulinemia, an altered glucose tolerance test and less liver insulin receptor substrate-2. Further, only fructose-fed female rats had increased adenosine 5'-monophosphate (AMP)-activated protein kinase activity, resulting in a decreased expression of hepatic nuclear factor 4 and sterol response element binding protein 1. These differences were related to the fact that liver expression of the enzyme fructokinase, controlling fructose metabolism, was markedly induced by fructose ingestion in female, but not in male rats, resulting in a significant increase in the AMP/adenosine 5'-triphosphate (ATP) ratio and, thus, AMP-activated protein kinase activation, in female rats only. The difference in fructokinase induction could explain the higher metabolic burden produced by fructose ingestion in the livers of female Sprague-Dawley rats.
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Affiliation(s)
- Laia Vilà
- Department of Pharmacology and Therapeutic Chemistry, School of Pharmacy, University of Barcelona, IBUB (Institute of Biomedicine University of Barcelona),and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona 08028, Spain
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