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Cui Q, Zhang Y, Tian N, Yang J, Ya D, Xiang W, Zhou Z, Jiang Y, Deng J, Yang B, Lin X, Li Q, Liao R. Leptin Promotes Angiogenesis via Pericyte STAT3 Pathway upon Intracerebral Hemorrhage. Cells 2022; 11:cells11172755. [PMID: 36078162 PMCID: PMC9454866 DOI: 10.3390/cells11172755] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 11/22/2022] Open
Abstract
Angiogenesis is a vital endogenous brain self-repair processes for neurological recovery after intracerebral hemorrhage (ICH). Increasing evidence suggests that leptin potentiates angiogenesis and plays a beneficial role in stroke. However, the proangiogenic effect of leptin on ICH has not been adequately explored. Moreover, leptin triggers post-ICH angiogenesis through pericyte, an important component of forming new blood vessels, which remains unclear. Here, we reported that exogenous leptin infusion dose-dependent promoted vascular endothelial cells survival and proliferation at chronic stage of ICH mice. Additionally, leptin robustly ameliorated pericytes loss, enhanced pericytes proliferation and migration in ICH mice in vivo, and in ICH human brain microvascular pericytes (HBVPC) in vitro. Notably, we showed that pericytes-derived pro-angiogenic factors were responsible for enhancing the survival, proliferation and tube formation followed leptin treatment in human brain microvascular endothelial cells (HCMEC/D3)/HBVPC co-culture models. Importantly, considerable improvements in neurobehavioral function and hostile microenvironment were observed in leptin treatment ICH mice, indicating that better vascular functionality post ICH improves outcome. Mechanistically, this study unveiled that leptin boost post-ICH angiogenesis potentially through modulation of leptin receptor (leptinR)/Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway in pericyte. Thus, leptin may be a lucrative option for the treatment of ICH.
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Affiliation(s)
- Qi Cui
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Yingmei Zhang
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Ning Tian
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Guangxi Clinical Research Center for Neurological Diseases, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Jiaxin Yang
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Dongshan Ya
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Wenjing Xiang
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Zixian Zhou
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Yanlin Jiang
- Department of Pharmacology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Jungang Deng
- Department of Pharmacology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Bin Yang
- Guangxi Clinical Research Center for Neurological Diseases, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Xiaohui Lin
- Department of Geriatrics, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Qinghua Li
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Guangxi Clinical Research Center for Neurological Diseases, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
| | - Rujia Liao
- Laboratory of Neuroscience, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Department of Neurology, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Guangxi Clinical Research Center for Neurological Diseases, Affiliated Hospital of Guilin Medical University, Guilin Medical University, Guilin 541004, China
- Correspondence: ; Tel.: +86-0773-2833025
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Cheng X, Jiang JM, Wang CY, Zou W, Zhang P, Tang XQ. Hydrogen sulfide prevents arecoline-induced neurotoxicity via promoting leptin/leptin receptor signaling pathway. Cell Biol Int 2022; 46:1355-1366. [PMID: 35819076 DOI: 10.1002/cbin.11850] [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: 06/25/2021] [Revised: 12/20/2021] [Accepted: 01/01/2022] [Indexed: 11/09/2022]
Abstract
Arecoline, a major alkaloid of the areca nut, has potential toxicity to the nervous system. Our previous study reveals that the neurotoxicity of arecoline involves in inhibited endogenous hydrogen sulfide (H2 S) generation. Therefore, the present study investigated whether exogenous H2 S protects against arecoline-induced neurotoxicity and further explore the underlying mechanisms focusing on leptin/leptin receptor signaling pathway. The cell viability was measured by CCK-8 kit. The apoptosis were detected by Hoechst 33258 and Annexin V/PI (propidium iodide) staining. The protein expressions were determined by Western blot analysis. Our results demonstrated that NaHS, an exogenous H2 S donor, significantly increases the cell viability, decreases apoptosis ratio, and reduces caspase-3 activity as well as Bax/Bcl-2 ratio in PC12 cells exposed to arecoline, indicating the protection of H2 S against arecoline-induced cytotoxicity and apoptosis. Also, NaHS attenuated arecoline-induced endoplasmic reticulum (ER) stress, as evidenced by the decreases in the expressions of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and Cleaved caspase-12. Meanwhile, NaHS promoted leptin/leptin receptor signaling pathway in arecoline-exposed PC12 cells, as illustrated by upregulations of leptin and leptin receptor expressions. Furthermore, leptin tA, an antagonist of leptin receptor, obviously abolished the inhibitory effects of NaHS on arecoline-induced cytotoxicity, apoptosis, and ER stress in arecoline-exposed PC12 cells. Taken together, these results suggested that H2 S prevents arecoline-induced neurotoxicity via enhancing the leptin/leptin receptor signaling pathway.
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Affiliation(s)
- Xiang Cheng
- The First Affiliated Hospital, Department of Clinical Laboratory, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China.,Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Institute of Neuroscience, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China
| | - Jia-Mei Jiang
- Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Institute of Neuroscience, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China.,The First Affiliated Hospital, Institute of Neurology, University of South China, Hengyang, Hunan, P.R. China
| | - Chun-Yan Wang
- Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Institute of Neuroscience, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China
| | - Wei Zou
- Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Institute of Neuroscience, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China.,The Affiliated Nanhua Hospital, Department of Neurology, University of South China, Hengyang, Hunan, P.R. China
| | - Ping Zhang
- Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Institute of Neuroscience, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China.,The Affiliated Nanhua Hospital, Department of Neurology, University of South China, Hengyang, Hunan, P.R. China
| | - Xiao-Qing Tang
- Key Laboratory for Cognitive Disorders and Neurodegenerative Diseases, Institute of Neuroscience, Hengyang Medical College, University of South China, Hengyang, Hunan, P.R. China.,The First Affiliated Hospital, Institute of Neurology, University of South China, Hengyang, Hunan, P.R. China
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Association of ADIPOQ-rs2241766 and FTO-rs9939609 genetic variants with body mass index trajectory in women of reproductive age over 6 years of follow-up: the PREDI study. Eur J Clin Nutr 2022; 76:159-172. [PMID: 33850313 DOI: 10.1038/s41430-021-00911-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/12/2021] [Accepted: 03/26/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Interindividual variations in body mass index (BMI) can be partially explained by genetic differences. We aimed to examine the association of the ADIPOQ-rs2241766, LEP-rs7799039 and FTO-rs9939609 genetic variants with BMI trajectory in women of reproductive age over 6 years of follow-up. METHODS This was a prospective study that used data from 435 women of the PREDI Study conducted in Brazil. Socioeconomic, biological and anthropometric data were collected at four time points: 2012 (baseline) in the maternity hospital, and 2013-14, 2016-17 and 2018 (1st, 2nd and 3rd follow-ups) at the participant's home. Genotyping was performed by PCR-RFLP. Linear mixed-effect and Poisson regression models were used to address the association of ADIPOQ, LEP and FTO genotypes with BMI and overweight/obesity status. RESULTS Women carrying the risk allele (TA or AA) of the FTO-rs9939609 genetic variant had a 1.16 kg/m2 higher BMI over the follow-up period than those carrying the wild-type genotype (TT), even when adjusted for potential confounders (95% CI: 0.23-2.10, p = 0.015). The risk of obesity associated with the FTO-TA or AA genotype decreased over the years, demonstrating an influence of time on its trajectory (IRR = 0.99, 95% CI: 0.98-0.99, p = 0.016). There was no variation in BMI trajectories for the ADIPOQ-rs2241766, LEP-rs7799039 or FTO-rs9939609 genetic variant. CONCLUSIONS The results of this study suggest that monitoring women of reproductive age with ADIPOQ-rs2241766 TG/GG or FTO-rs9939609 TA/AA genotypes may be an important strategy to reduce maternal excess body weight and, consequently, the long-term public health burden of obesity.
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Leptin Reduces Plin5 m 6A Methylation through FTO to Regulate Lipolysis in Piglets. Int J Mol Sci 2021; 22:ijms221910610. [PMID: 34638947 PMCID: PMC8508756 DOI: 10.3390/ijms221910610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 12/17/2022] Open
Abstract
Perilipin5 (Plin5) is a scaffold protein that plays an important role in lipid droplets (LD) formation, but the regulatory effect of leptin on it is unclear. Our study aimed to explore the underlying mechanisms by which leptin reduces the N6-methyladenosine (m6A) methylation of Plin5 through fat mass and obesity associated genes (FTO) and regulates the lipolysis. To this end, 24 Landrace male piglets (7.73 ± 0.38 kg) were randomly sorted into two groups, either a control group (Control, n = 12) or a 1 mg/kg leptin recombinant protein treatment group (Leptin, n = 12). After 4 weeks of treatment, the results showed that leptin treatment group had lower body weight, body fat percentage and blood lipid levels, but the levels of Plin5 mRNA and protein increased significantly in adipose tissue (p < 0.05). Leptin promotes the up-regulation of FTO expression level in vitro, which in turn leads to the decrease of Plin5 M6A methylation (p < 0.05). In in vitro porcine adipocytes, overexpression of FTO aggravated the decrease of M6A methylation and increased the expression of Plin5 protein, while the interference fragment of FTO reversed the decrease of m6A methylation (p < 0.05). Finally, the overexpression in vitro of Plin5 significantly reduces the size of LD, promotes the metabolism of triglycerides and the operation of the mitochondrial respiratory chain, and increases thermogenesis. This study clarified that leptin can regulate Plin5 M6A methylation by promoting FTO to affect the lipid metabolism and energy consumption, providing a theoretical basis for treating diseases related to obesity.
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Mehrdad M, Doaei S, Gholamalizadeh M, Eftekhari MH. The association between FTO genotype with macronutrients and calorie intake in overweight adults. Lipids Health Dis 2020; 19:197. [PMID: 32843047 PMCID: PMC7449073 DOI: 10.1186/s12944-020-01372-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 08/13/2020] [Indexed: 01/18/2023] Open
Abstract
Background Dietary macronutrients may indirectly affect body weight through their interactions with the fat mass and obesity associated (FTO) gene. This study aimed to investigate the association between FTO gene rs9939609 polymorphism with macronutrients intake in overweight adults. Methods This study was carried out on 196 overweight adults of Shiraz, Iran. Dietary intake was assessed using a validated 168-item semi-quantitative food frequency questionnaire (FFQ). The FTO gene was genotyped for rs9939609 polymorphism. The association between dietary macronutrients and the FTO genotype were assessed using linear regression after adjustments for sex, age, physical activity, and the serum levels of triglycerides, fasting blood sugar (FBS), and low density lipoprotein (LDL). Results The higher intake of carbohydrates (P < 0.001), fat (P = 0.009), and calorie (P = 0.001) were significantly associated with rs9939609 AA genotype (P = 0.001). Carriers of the AA genotype of rs9939609 had significantly higher calorie, fat, and carbohydrate intake than the carriers of the TT genotype after adjusting for age and sex (P = 0.019, P = 0.010 and P = 0.001, respectively). Further adjustments for physical activity, TG, LDL, and FBS did not change these results. Conclusion The amounts of dietary calorie, carbohydrate, and fat intake were associated with FTO genotype. Further studies are warranted to confirm these associations and to identify the underlying mechanisms.
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Affiliation(s)
- Mahsa Mehrdad
- Department of Clinical Nutrition, School of Nutrition and food Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saeid Doaei
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. .,Research Center of Health and Environment, Guilan University of Medical Sciences, Rasht, Iran.
| | - Maryam Gholamalizadeh
- Student research committee, Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Hassan Eftekhari
- Department of Clinical Nutrition, School of Nutrition and food Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
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Wang X, Zhang X, Qiu C, Yang N. STAT3 Contributes to Radioresistance in Cancer. Front Oncol 2020; 10:1120. [PMID: 32733808 PMCID: PMC7358404 DOI: 10.3389/fonc.2020.01120] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 06/04/2020] [Indexed: 12/14/2022] Open
Abstract
Radiotherapy has been used in the clinic for more than one century and it is recognized as one of the main methods in the treatment of malignant tumors. Signal Transducers and Activators of Transcription 3 (STAT3) is reported to be upregulated in many tumor types, and it is believed to be involved in the tumorigenesis, development and malignant behaviors of tumors. Previous studies also found that STAT3 contributes to chemo-resistance of various tumor types. Recently, many studies reported that STAT3 is involved in the response of tumor cells to radiotherapy. But until now, the role of the STAT3 in radioresistance has not been systematically demonstrated. In this study, we will review the radioresistance induced by STAT3 and relative solutions will be discussed.
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Affiliation(s)
- Xuehai Wang
- Department of Otolaryngology, Weihai Municipal Hospital, Shandong University, Weihai, China
| | - Xin Zhang
- Department of Neurosurgery, Qilu Hospital of Shandong University and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China.,Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
| | - Chen Qiu
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, China
| | - Ning Yang
- Department of Neurosurgery, Qilu Hospital of Shandong University and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China.,Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
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Liu SJ, Tang HL, He Q, Lu P, Fu T, Xu XL, Su T, Gao MM, Duan S, Luo Y, Long YS. FTO is a transcriptional repressor to auto-regulate its own gene and potentially associated with homeostasis of body weight. J Mol Cell Biol 2020; 11:118-132. [PMID: 29771336 DOI: 10.1093/jmcb/mjy028] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/26/2018] [Accepted: 05/15/2018] [Indexed: 01/11/2023] Open
Abstract
Fat mass and obesity-associated (FTO) protein is a ferrous ion (Fe2+)/2-oxoglutarate (2-OG)-dependent demethylase preferentially catalyzing m6A sites in RNA. The FTO gene is highly expressed in the hypothalamus with fluctuation in response to various nutritional conditions, which is believed to be involved in the control of whole body metabolism. However, the underlying mechanism in response to different nutritional cues remains poorly understood. Here we show that ketogenic diet-derived ketone body β-hydroxybutyrate (BHB) transiently increases FTO expression in both mouse hypothalamus and cultured cells. Interestingly, the FTO protein represses Fto promoter activity, which can be offset by BHB. We then demonstrate that FTO binds to its own gene promoter, and Fe2+, but not 2-OG, impedes this binding and increases FTO expression. The BHB-induced occupancy of the promoter by FTO influences the assembly of the basal transcriptional machinery. Importantly, a loss-of-function FTO mutant (I367F), which induces a lean phenotype in FTOI367F mice, exhibits augmented binding and elevated potency to repress the promoter. Furthermore, FTO fails to bind to its own promoter that promotes FTO expression in the hypothalamus of high-fat diet-induced obese and 48-h fasting mice, suggesting a disruption of the stable expression of this gene. Taken together, this study uncovers a new function of FTO as a Fe2+-sensitive transcriptional repressor dictating its own gene switch to form an auto-regulatory loop that may link with the hypothalamic control of body weight.
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Affiliation(s)
- Shu-Jing Liu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Hui-Ling Tang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Qian He
- School of Basic Medical Sciences, Zhejiang University, Hangzhou, China
| | - Ping Lu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Tao Fu
- School of Basic Medical Sciences, Zhejiang University, Hangzhou, China
| | - Xu-Ling Xu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Tao Su
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Mei-Mei Gao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shumin Duan
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Luo
- School of Basic Medical Sciences, Zhejiang University, Hangzhou, China
| | - Yue-Sheng Long
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
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Gill R, Stratigopoulos G, Lee JH, Leibel RL. Functional genomic characterization of the FTO locus in African Americans. Physiol Genomics 2019; 51:517-528. [PMID: 31530225 DOI: 10.1152/physiolgenomics.00057.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND SNPs in the first intron of the fat mass and obesity-associated (FTO) gene represent the strongest genome-wide associations with adiposity [body mass index (BMI)]; the molecular basis for these associations is under intense investigation. In European populations, the focus of most genome-wide association studies conducted to date, the single nucleotide polymorphisms (SNPs) have indistinguishable associations due to the high level of linkage disequilibrium (LD). However, in African American (AA) individuals, reduced LD and increased haplotype diversity permit finer distinctions among obesity-associated SNPs. Such distinctions are important to mechanistic inferences and for selection of disease SNPs relevant to specific populations. METHODS To identify specific FTO SNP(s) directly related to adiposity, we performed: 1) haplotype analyses of individual-level data in 3,335 AAs from the Atherosclerosis Risk in Communities Cohort (ARIC) study; as well as 2) statistical fine-mapping using summary statistics from a study of FTO in over 20 000 AAs and over 1000 functional genomic annotations. RESULTS Our haplotype analyses suggest that in AAs at least two distinct signals underlie the intron 1 FTO-adiposity signal. Fine mapping showed that two SNPs have the highest posterior probability of association (PPA) with BMI: rs9927317 (PPA = 0.94) and rs62033405 (PPA = 0.99). These variants overlap possible enhancer sites and the 5'-regions of transcribed genes in the substantia nigra, chondrocytes, and white adipocytes. CONCLUSIONS We found two SNPs in FTO with the highest probability of direct association with BMI in AAs, as well as tissue-specific mechanisms by which these variants may contribute to the pathogenesis of obesity.
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Affiliation(s)
- Richard Gill
- Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York.,Department of Epidemiology, Mailman School of Public Health, Columbia University Medical Center, New York, New York.,Genomics Analysis Unit, Amgen Research, Cambridge, Massachusetts
| | - George Stratigopoulos
- Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York
| | - Joseph H Lee
- Department of Epidemiology, Mailman School of Public Health, Columbia University Medical Center, New York, New York.,The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York.,Gertrude H. Sergievsky Center, Columbia University, New York, New York
| | - Rudolph L Leibel
- Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York
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Almeida SM, Furtado JM, Mascarenhas P, Ferraz ME, Ferreira JC, Monteiro MP, Vilanova M, Ferraz FP. Association between LEPR, FTO, MC4R, and PPARG-2 polymorphisms with obesity traits and metabolic phenotypes in school-aged children. Endocrine 2018; 60:466-478. [PMID: 29679223 PMCID: PMC5937906 DOI: 10.1007/s12020-018-1587-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/19/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE Evaluate the relationship of leptin receptor (LEPR) rs1137101, fat mass obesity-associated (FTO) receptors 9939609, melanocortin-4 receptors (MC4R) rs2229616 and rs17782313, and proliferator-activated receptor-gamma (PPARG) rs1801282 with clinical and metabolic phenotypes in prepubertal children. RESEARCH QUESTION What is the effect of polymorphisms on clinical and metabolic phenotypes in prepubertal children? METHODS A cross-sectional descriptive study was performed to evaluate anthropometric features, percentage body fat (%BF), biochemical parameters, and genotype in 773 prepubertal children. RESULTS FTO rs9939609 was associated with an increase in body mass index (BMI) and BMI z-score (zBMI). MC4R rs17782313 was associated with a decrease in BMI and +0.06 units in zBMI. LEPR, and PPARG-2 polymorphisms were associated with decreases in BMI and an increase and decrease units in zBMI, respectively. The homozygous SNPs demonstrated increases (FTO rs993609 and MC4R rs17782313) and decreases (LEPR rs1137101, PPARG rs1801282) in zBMI than the homozygous form of the major allele. In the overweight/obese group, the MC4R rs17782313 CC genotype showed higher average weight, zBMI, waist circumference, waist-circumference-to-height ratio, and waist-hip ratio, and lower BMI, mid-upper arm circumference, calf circumference, and %BF (P< 0.05). FTO rs9939609 AT and AA genotypes were associated with lower triglycerides (P < 0.05). CONCLUSIONS We showed that MC4R rs17782313 and FTO rs9939609 were positively associated with zBMI, with weak and very weak effects, respectively, suggesting a very scarce contribution to childhood obesity. LEPR rs1137101 and PPARG-2 rs1801282 had weak and medium negative effects on zBMI, respectively, and may slightly protect against childhood obesity.
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Affiliation(s)
- Sílvia M Almeida
- Centro de Genética Médica e Nutrição Pediátrica Egas Moniz, Campus Universitário, Monte da Caparica, Portugal.
- Instituto Universitário Egas Moniz, Campus Universitário, Monte da Caparica, Portugal.
| | - José M Furtado
- Centro de Genética Médica e Nutrição Pediátrica Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
- Instituto Universitário Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
| | - Paulo Mascarenhas
- Instituto Universitário Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
| | - Maria E Ferraz
- Centro de Genética Médica e Nutrição Pediátrica Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
| | - José C Ferreira
- Centro de Genética Médica e Nutrição Pediátrica Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
| | - Mariana P Monteiro
- Clinical and Experimental Endocrinology Group, Unit for Multidisciplinary Research in Biomedicine UMIB, ICBAS, University of Porto, Porto, Portugal
| | - Manuel Vilanova
- Instituto de Investigação e Inovação em Saúde, and IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Fernando P Ferraz
- Centro de Genética Médica e Nutrição Pediátrica Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
- Instituto Universitário Egas Moniz, Campus Universitário, Monte da Caparica, Portugal
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Rossetti C, Sciarra D, Petit JM, Eap CB, Halfon O, Magistretti PJ, Boutrel B, Cardinaux JR. Gender-specific alteration of energy balance and circadian locomotor activity in the Crtc1 knockout mouse model of depression. Transl Psychiatry 2017; 7:1269. [PMID: 29217834 PMCID: PMC5802703 DOI: 10.1038/s41398-017-0023-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 07/28/2017] [Accepted: 09/07/2017] [Indexed: 02/04/2023] Open
Abstract
Obesity and depression are major public health concerns, and there is increasing evidence that they share etiological mechanisms. CREB-regulated transcription coactivator 1 (CRTC1) participates in neurobiological pathways involved in both mood and energy balance regulation. Crtc1 -/- mice rapidly develop a depressive-like and obese phenotype in early adulthood, and are therefore a relevant animal model to explore possible common mechanisms underlying mood disorders and obesity. Here, the obese phenotype of male and female Crtc1 -/- mice was further characterized by investigating CRTC1's role in the homeostatic and hedonic regulation of food intake, as well as its influence on daily locomotor activity. Crtc1 -/- mice showed a strong gender difference in the homeostatic regulation of energy balance. Mutant males were hyperphagic and rapidly developed obesity on normal chow diet, whereas Crtc1 -/- females exhibited mild late-onset obesity without hyperphagia. Overeating of mutant males was accompanied by alterations in the expression of several orexigenic and anorexigenic hypothalamic genes, thus confirming a key role of CRTC1 in the central regulation of food intake. No alteration in preference and conditioned response for saccharine was observed in Crtc1 -/- mice, suggesting that mutant males' hyperphagia was not due to an altered hedonic regulation of food intake. Intriguingly, mutant males exhibited a hyperphagic behavior only during the resting (diurnal) phase of the light cycle. This abnormal feeding behavior was associated with a higher diurnal locomotor activity indicating that the lack of CRTC1 may affect circadian rhythmicity. Collectively, these findings highlight the male-specific involvement of CRTC1 in the central control of energy balance and circadian locomotor activity.
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Affiliation(s)
- Clara Rossetti
- 0000 0001 2165 4204grid.9851.5Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland ,0000 0001 2165 4204grid.9851.5Service of Child and Adolescent Psychiatry, Department of Psychiatry, University Medical Center, University of Lausanne, Lausanne, Switzerland
| | - Daniel Sciarra
- 0000 0001 2165 4204grid.9851.5Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland
| | - Jean-Marie Petit
- 0000 0001 2165 4204grid.9851.5Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland ,0000000121839049grid.5333.6Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Chin B. Eap
- 0000 0001 2165 4204grid.9851.5Unit of Pharmacogenetics and Clinical Psychopharmacology, Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland ,0000 0001 2322 4988grid.8591.5School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Olivier Halfon
- 0000 0001 2165 4204grid.9851.5Service of Child and Adolescent Psychiatry, Department of Psychiatry, University Medical Center, University of Lausanne, Lausanne, Switzerland
| | - Pierre J. Magistretti
- 0000 0001 2165 4204grid.9851.5Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland ,0000000121839049grid.5333.6Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland ,0000 0001 1926 5090grid.45672.32Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Benjamin Boutrel
- 0000 0001 2165 4204grid.9851.5Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland ,0000 0001 2165 4204grid.9851.5Service of Child and Adolescent Psychiatry, Department of Psychiatry, University Medical Center, University of Lausanne, Lausanne, Switzerland
| | - Jean-René Cardinaux
- Center for Psychiatric Neuroscience, Department of Psychiatry, University Medical Center, University of Lausanne, Prilly, Switzerland. .,Service of Child and Adolescent Psychiatry, Department of Psychiatry, University Medical Center, University of Lausanne, Lausanne, Switzerland.
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11
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Zhou Y, Hambly BD, McLachlan CS. FTO associations with obesity and telomere length. J Biomed Sci 2017; 24:65. [PMID: 28859657 PMCID: PMC5580219 DOI: 10.1186/s12929-017-0372-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 08/23/2017] [Indexed: 12/16/2022] Open
Abstract
This review examines the biology of the Fat mass- and obesity-associated gene (FTO), and the implications of genetic association of FTO SNPs with obesity and genetic aging. Notably, we focus on the role of FTO in the regulation of methylation status as possible regulators of weight gain and genetic aging. We present a theoretical review of the FTO gene with a particular emphasis on associations with UCP2, AMPK, RBL2, IRX3, CUX1, mTORC1 and hormones involved in hunger regulation. These associations are important for dietary behavior regulation and cellular nutrient sensing via amino acids. We suggest that these pathways may also influence telomere regulation. Telomere length (TL) attrition may be influenced by obesity-related inflammation and oxidative stress, and FTO gene-involved pathways. There is additional emerging evidence to suggest that telomere length and obesity are bi-directionally associated. However, the role of obesity risk-related genotypes and associations with TL are not well understood. The FTO gene may influence pathways implicated in regulation of TL, which could help to explain some of the non-consistent relationship between weight phenotype and telomere length that is observed in population studies investigating obesity.
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Affiliation(s)
- Yuling Zhou
- Rural Clinical School, University of New South Wales, Sydney, 2052, Australia
| | - Brett D Hambly
- Discipline of Pathology and Bosch Institute, University of Sydney, Sydney, Australia
| | - Craig S McLachlan
- Rural Clinical School, University of New South Wales, Sydney, 2052, Australia.
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12
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Abstract
Leptin is a peptide hormone produced by adipose tissue and acts in brain centers to control critical physiological functions. Leptin receptors are especially abundant in the hypothalamus and trigger specific neuronal subpopulations, and activate several intracellular signaling events, including the JAK/STAT, MAPK, PI3K, and mTOR pathway. Although most studies focus on its role in energy intake and expenditure, leptin also plays a critical role in many central nervous system diseases.
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13
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Zheng SL, Li ZY, Song J, Liu JM, Miao CY. Metrnl: a secreted protein with new emerging functions. Acta Pharmacol Sin 2016; 37:571-9. [PMID: 27063217 PMCID: PMC4857552 DOI: 10.1038/aps.2016.9] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/24/2016] [Indexed: 12/15/2022] Open
Abstract
Secreted proteins play critical roles in physiological and pathological processes and can be used as biomarkers and therapies for aging and disease. Metrnl is a novel secreted protein homologous to the neurotrophin Metrn. But this protein, unlike Metrn that is mainly expressed in the brain, shows a relatively wider distribution in the body with high levels of expression in white adipose tissue and barrier tissues. This protein plays important roles in neural development, white adipose browning and insulin sensitization. Based on its expression and distinct functions, this protein is also called Cometin, Subfatin and Interleukin 39, which refer to its neurotrophic effect, adipokine function and the possible action as a cytokine, respectively. The spectrum of Metrnl functions remains to be determined, and the mechanisms of Metrnl action need to be elucidated. In this review, we focus on the discovery, structural characteristics, expression pattern and physiological functions of Metrnl, which will assist in developing this protein as a new therapeutic target or agent.
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Affiliation(s)
- Si-li Zheng
- Department of Pharmacology, Second Military Medical University, Shanghai 200433, China
| | - Zhi-yong Li
- Department of Pharmacology, Second Military Medical University, Shanghai 200433, China
| | - Jie Song
- Department of Pharmacology, Second Military Medical University, Shanghai 200433, China
| | - Jian-min Liu
- Stroke Center & Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China
| | - Chao-yu Miao
- Department of Pharmacology, Second Military Medical University, Shanghai 200433, China
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing 100069, China
- E-mail
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14
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Stratigopoulos G, Burnett LC, Rausch R, Gill R, Penn DB, Skowronski AA, LeDuc CA, Lanzano AJ, Zhang P, Storm DR, Egli D, Leibel RL. Hypomorphism of Fto and Rpgrip1l causes obesity in mice. J Clin Invest 2016; 126:1897-910. [PMID: 27064284 DOI: 10.1172/jci85526] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/25/2016] [Indexed: 01/19/2023] Open
Abstract
Noncoding polymorphisms in the fat mass and obesity-associated (FTO) gene represent common alleles that are strongly associated with effects on food intake and adiposity in humans. Previous studies have suggested that the obesity-risk allele rs8050136 in the first intron of FTO alters a regulatory element recognized by the transcription factor CUX1, thereby leading to decreased expression of FTO and retinitis pigmentosa GTPase regulator-interacting protein-1 like (RPGRIP1L). Here, we evaluated the effects of rs8050136 and another potential CUX1 element in rs1421085 on expression of nearby genes in human induced pluripotent stem cell-derived (iPSC-derived) neurons. There were allele-dosage effects on FTO, RPGRIP1L, and AKT-interacting protein (AKTIP) expression, but expression of other vicinal genes, including IRX3, IRX5, and RBL2, which have been implicated in mediating functional effects, was not altered. In vivo manipulation of CUX1, Fto, and/or Rpgrip1l expression in mice affected adiposity in a manner that was consistent with CUX1 influence on adiposity via remote effects on Fto and Rpgrip1l expression. In support of a mechanism, mice hypomorphic for Rpgrip1l exhibited hyperphagic obesity, as the result of diminished leptin sensitivity in Leprb-expressing neurons. Together, the results of this study indicate that the effects of FTO-associated SNPs on energy homeostasis are due in part to the effects of these genetic variations on hypothalamic FTO, RPGRIP1L, and possibly other genes.
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15
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Xiang L, Wu H, Pan A, Patel B, Xiang G, Qi L, Kaplan RC, Hu F, Wylie-Rosett J, Qi Q. FTO genotype and weight loss in diet and lifestyle interventions: a systematic review and meta-analysis. Am J Clin Nutr 2016; 103:1162-70. [PMID: 26888713 PMCID: PMC4807705 DOI: 10.3945/ajcn.115.123448] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/20/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Studies have suggested that the fat mass and obesity-associated (FTO) genotype is associated with individual variability in weight loss in response to diet/lifestyle interventions, but results are inconsistent. OBJECTIVE We aimed to provide a summary of the literature evaluating the relation between the FTO genotype and weight loss in response to diet/lifestyle interventions. DESIGN A search of English-language articles in the PubMed and Embase databases (through 30 April 2015) was performed. Eligible studies were diet/lifestyle weight-loss intervention studies conducted in adults that reported changes in body weight or body mass index (BMI) by the FTO variant rs9939609 (or its proxy). Differences in weight loss between FTO genotypes across studies were pooled with the use of fixed-effect models. RESULTS A meta-analysis of 10 studies (comprising 6951 participants) that reported the results of additive genetic models showed that individuals with the FTO TA genotype and AA genotype (those with the obesity-predisposing A allele) had 0.18-kg (95% CI: -0.09-, 0.45-kg;P= 0.19; NS) and 0.44-kg (95% CI: 0.09-, 0.79-kg;P= 0.015) greater weight loss, respectively, than those with the TT genotype. A meta-analysis of 14 studies (comprising 7700 participants) that reported the results of dominant genetic models indicated a 0.20-kg (-0.43-, 0.04-kg) greater weight loss in the TA/AA genotype than in the TT genotype (P= 0.10). In addition, differences in weight loss between the AA genotype and TT genotype were significant in studies with a diet intervention only, adjustment for baseline BMI or body weight, and several other subgroups. However, the relatively small number of studies limited these stratified analyses, and there was no statistically significant difference between subgroups. CONCLUSIONS This meta-analysis suggests that individuals carrying the homozygous FTO obesity-predisposing allele may lose more weight through diet/lifestyle interventions than noncarriers. Our data provide evidence for genetic variability in response to diet/lifestyle interventions on weight loss, although clinical applications of these findings need further investigations.
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Affiliation(s)
- Lingwei Xiang
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Hongyu Wu
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA
| | - An Pan
- School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bhakti Patel
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Guangda Xiang
- Department of Endocrinology, Wuhan General Hospital of Guangzhou Command, Wuhan, China; and
| | - Lu Qi
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Robert C Kaplan
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Frank Hu
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Judith Wylie-Rosett
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Qibin Qi
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY;
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16
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Furtek SL, Backos DS, Matheson CJ, Reigan P. Strategies and Approaches of Targeting STAT3 for Cancer Treatment. ACS Chem Biol 2016; 11:308-18. [PMID: 26730496 DOI: 10.1021/acschembio.5b00945] [Citation(s) in RCA: 289] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates the expression of genes related to cell cycle, cell survival, and immune response associated with cancer progression and malignancy in a number of cancer types. Once activated, STAT3 forms a homodimer and translocates to the nucleus where it binds DNA promoting the translation of target genes associated with antiapoptosis, angiogenesis, and invasion/migration. In normal cells, levels of activated STAT3 remain transient; however, STAT3 remains constitutively active in approximately 70% of human solid tumors. The pivotal role of STAT3 in tumor progression has promoted a campaign in drug discovery to identify small molecules that disrupt the function of STAT3. A range of approaches have been used to identify novel small molecule inhibitors of STAT3, including high-throughput screening of chemical libraries, computational-based virtual screening, and fragment-based design strategies. The most common approaches in targeting STAT3 activity are either via the inhibition of tyrosine kinases capable of phosphorylating and thereby activating STAT3 or by preventing the formation of functional STAT3 dimers through disruption of the SH2 domains. However, the targeting of the STAT3 DNA-binding domain and disruption of binding of STAT3 to its DNA promoter have not been thoroughly examined, mainly due to the lack of adequate assay systems. This review summarizes the development of STAT3 inhibitors organized by the approach used to inhibit STAT3, the current inhibitors of each class, and the assay systems used to evaluate STAT3 inhibition and offers an insight into future approaches for small molecule STAT3 inhibitor development.
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Affiliation(s)
- Steffanie L. Furtek
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 East Montview Boulevard, Aurora, Colorado 80045, United States
| | - Donald S. Backos
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 East Montview Boulevard, Aurora, Colorado 80045, United States
| | - Christopher J. Matheson
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 East Montview Boulevard, Aurora, Colorado 80045, United States
| | - Philip Reigan
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 East Montview Boulevard, Aurora, Colorado 80045, United States
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17
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Wang CY, Shie SS, Tsai ML, Yang CH, Hung KC, Wang CC, Hsieh IC, Wen MS. FTO modulates fibrogenic responses in obstructive nephropathy. Sci Rep 2016; 6:18874. [PMID: 26727661 PMCID: PMC4698750 DOI: 10.1038/srep18874] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/30/2015] [Indexed: 12/24/2022] Open
Abstract
Genome-wide association studies have shown that variants in fat mass and obesity-associated (FTO) gene are robustly associated with body mass index and obesity. These FTO variants are also associated with end stage renal disease and all-cause mortality in chronic kidney diseases. However, the exact role of FTO in kidneys is currently unknown. Here we show that FTO expression is increased after ureteral obstruction and renal fibrosis. Deficiency of the FTO gene attenuates the fibrogenic responses induced by ureteral obstruction in the kidney. Renal tubular cells deficient of FTO produce less α-SMA after TGF-β stimulation. FTO is indispensable for the extracellular matrix synthesis after ureteral obstruction in kidneys. Indeed, global gene transcriptions amplitude is reduced in FTO deficient kidneys after ureteral obstruction. These data establish the importance of FTO in renal fibrosis, which may have potential therapeutic implications.
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Affiliation(s)
- Chao-Yung Wang
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
| | - Shian-Sen Shie
- Department of Infectious Diseases, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taiwan
| | - Ming-Lung Tsai
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
| | - Chia-Hung Yang
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
| | - Kuo-Chun Hung
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
| | - Chun-Chieh Wang
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
| | - I-Chang Hsieh
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
| | - Ming-Shien Wen
- Department of Cardiology, Chang Gung Memorial Hospital, and Chang Gung University College of Medicine, Taiwan
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18
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Zhang M, Zhang Y, Ma J, Guo F, Cao Q, Zhang Y, Zhou B, Chai J, Zhao W, Zhao R. The Demethylase Activity of FTO (Fat Mass and Obesity Associated Protein) Is Required for Preadipocyte Differentiation. PLoS One 2015. [PMID: 26218273 PMCID: PMC4517749 DOI: 10.1371/journal.pone.0133788] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
FTO (fat mass and obesity associated gene) was genetically identified to be associated with body mass index (BMI), presumably through functional regulation of energy homeostasis. However, the cellular and molecular mechanisms by which FTO functions remain largely unknown. Using 3T3-L1 preadipocyte as a model to study the role of FTO in adipogenesis, we demonstrated that FTO is functionally required for 3T3-L1 differentiation. FTO knock-down with siRNA inhibited preadipocyte differentiation, whereas ectopic over-expression of FTO enhanced the process. The demethylase activity of FTO is required for differentiation. Level of N6-methyladenosine (m6A) is decreased in cells over-expressing FTO. In contrast, overexpression of R96Q, a FTO missense mutant lack of demethylase activity, had no effect on cellular m6A level and impeded differentiation. Treatment with Rosiglitazone, a PPARγ agonist, could overcome the differentiation inhibition imposed by R96Q mutant, suggesting the effect of FTO is mediated through PPARγ.
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Affiliation(s)
- Meizi Zhang
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Ying Zhang
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Jun Ma
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Feima Guo
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Qian Cao
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Yu Zhang
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Bin Zhou
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jijie Chai
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Wenqing Zhao
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
| | - Renbin Zhao
- Space Biology Research and Technology Center, China Academy of Space Technology, Beijing Engineering Research Center of Space Biology, Beijing, 100190, China
- * E-mail:
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19
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Qi Q, Downer MK, Kilpeläinen TO, Taal HR, Barton SJ, Ntalla I, Standl M, Boraska V, Huikari V, Kiefte-de Jong JC, Körner A, Lakka TA, Liu G, Magnusson J, Okuda M, Raitakari O, Richmond R, Scott RA, Bailey MES, Scheuermann K, Holloway JW, Inskip H, Isasi CR, Mossavar-Rahmani Y, Jaddoe VWV, Laitinen J, Lindi V, Melén E, Pitsiladis Y, Pitkänen N, Snieder H, Heinrich J, Timpson NJ, Wang T, Yuji H, Zeggini E, Dedoussis GV, Kaplan RC, Wylie-Rosett J, Loos RJF, Hu FB, Qi L. Dietary Intake, FTO Genetic Variants, and Adiposity: A Combined Analysis of Over 16,000 Children and Adolescents. Diabetes 2015; 64:2467-76. [PMID: 25720386 PMCID: PMC4876751 DOI: 10.2337/db14-1629] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 02/12/2015] [Indexed: 12/26/2022]
Abstract
The FTO gene harbors variation with the strongest effect on adiposity and obesity risk. Previous data support a role for FTO variation in influencing food intake. We conducted a combined analysis of 16,094 boys and girls aged 1-18 years from 14 studies to examine the following: 1) the association between the FTO rs9939609 variant (or a proxy) and total energy and macronutrient intake; and 2) the interaction between the FTO variant and dietary intake, and the effect on BMI. We found that the BMI-increasing allele (minor allele) of the FTO variant was associated with increased total energy intake (effect per allele = 14.3 kcal/day [95% CI 5.9, 22.7 kcal/day], P = 6.5 × 10(-4)), but not with protein, carbohydrate, or fat intake. We also found that protein intake modified the association between the FTO variant and BMI (interactive effect per allele = 0.08 SD [0.03, 0.12 SD], P for interaction = 7.2 × 10(-4)): the association between FTO genotype and BMI was much stronger in individuals with high protein intake (effect per allele = 0.10 SD [0.07, 0.13 SD], P = 8.2 × 10(-10)) than in those with low intake (effect per allele = 0.04 SD [0.01, 0.07 SD], P = 0.02). Our results suggest that the FTO variant that confers a predisposition to higher BMI is associated with higher total energy intake, and that lower dietary protein intake attenuates the association between FTO genotype and adiposity in children and adolescents.
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Affiliation(s)
- Qibin Qi
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY Department of Nutrition, Harvard School of Public Health, Boston, MA
| | - Mary K Downer
- Department of Nutrition, Harvard School of Public Health, Boston, MA
| | - Tuomas O Kilpeläinen
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital and University of Cambridge, Cambridge, U.K. The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H Rob Taal
- The Generation R Study Group, Erasmus Medical Center, Rotterdam, the Netherlands Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands Department of Pediatrics, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Sheila J Barton
- MRC Lifecourse Epidemiology Unit, Faculty of Medicine, University of Southampton, Southampton, U.K
| | - Ioanna Ntalla
- Department of Nutrition and Dietetics, School of Health Science and Education, Harokopio University, Athens, Greece Department of Health Sciences, University of Leicester, Leicester, U.K
| | - Marie Standl
- Institute of Epidemiology I, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | - Vesna Boraska
- Wellcome Trust Sanger Institute, Hixton, Cambridge, U.K. Department of Medical Biology, University of Split School of Medicine, Split, Croatia
| | - Ville Huikari
- Institute of Health Sciences, University of Oulu, Oulu, Finland
| | - Jessica C Kiefte-de Jong
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands Global Public Health, Leiden University College, Hague, the Netherlands
| | - Antje Körner
- Pediatric Research Center, Department of Women's & Child Health, University of Leipzig, Leipzig, Germany
| | - Timo A Lakka
- Institute of Biomedicine, Department of Physiology, University of Eastern Finland, Kuopio, Finland Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland Kuopio Research Institute of Exercise Medicine, Kuopio, Finland
| | - Gaifen Liu
- Department of Neurology, Beijing Tian Tan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Jessica Magnusson
- Institute of Environmental Medicine, Karolinska Institutet, and Sachs' Children and Youth Hospital, Stockholm, Sweden
| | - Masayuki Okuda
- Graduate School of Science and Engineering, Yamaguchi University, Ube, Japan
| | - Olli Raitakari
- The Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku, Finland
| | - Rebecca Richmond
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, U.K
| | - Robert A Scott
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital and University of Cambridge, Cambridge, U.K
| | - Mark E S Bailey
- School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, U.K
| | - Kathrin Scheuermann
- Pediatric Research Center, Department of Women's & Child Health, University of Leipzig, Leipzig, Germany
| | - John W Holloway
- Human Genetics and Medical Genomics, Faculty of Medicine, University of Southampton, Southampton, U.K
| | - Hazel Inskip
- MRC Lifecourse Epidemiology Unit, Faculty of Medicine, University of Southampton, Southampton, U.K
| | - Carmen R Isasi
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Yasmin Mossavar-Rahmani
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Vincent W V Jaddoe
- The Generation R Study Group, Erasmus Medical Center, Rotterdam, the Netherlands Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands Department of Pediatrics, Erasmus Medical Center, Rotterdam, the Netherlands
| | | | - Virpi Lindi
- Institute of Biomedicine, Department of Physiology, University of Eastern Finland, Kuopio, Finland
| | - Erik Melén
- Institute of Environmental Medicine, Karolinska Institutet, and Sachs' Children and Youth Hospital, Stockholm, Sweden
| | - Yannis Pitsiladis
- School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, U.K
| | - Niina Pitkänen
- The Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland
| | - Harold Snieder
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands Georgia Prevention Center, Department of Pediatrics, Georgia Regents University, Augusta, GA
| | - Joachim Heinrich
- Institute of Epidemiology I, Helmholtz Zentrum München-German Research Center for Environmental Health, Neuherberg, Germany
| | | | - Tao Wang
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Hinoda Yuji
- Hokkaido Nursing College, Chuo-ku, Sapporo, Japan
| | | | - George V Dedoussis
- Department of Nutrition and Dietetics, School of Health Science and Education, Harokopio University, Athens, Greece
| | - Robert C Kaplan
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Judith Wylie-Rosett
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Ruth J F Loos
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital and University of Cambridge, Cambridge, U.K. The Genetics of Obesity and Related Metabolic Traits Program, The Charles Bronfman Institute for Personalized Medicine, The Mindich Child Health and Development Institute, Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York City, NY
| | - Frank B Hu
- Department of Nutrition, Harvard School of Public Health, Boston, MA Department of Epidemiology, Harvard School of Public Health, Boston, MA Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Lu Qi
- Department of Nutrition, Harvard School of Public Health, Boston, MA Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
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Merkestein M, Sellayah D. Role of FTO in Adipocyte Development and Function: Recent Insights. Int J Endocrinol 2015; 2015:521381. [PMID: 26788058 PMCID: PMC4695642 DOI: 10.1155/2015/521381] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 01/11/2023] Open
Abstract
In 2007, FTO was identified as the first genome-wide association study (GWAS) gene associated with obesity in humans. Since then, various animal models have served to establish the mechanistic basis behind this association. Many earlier studies focussed on FTO's effects on food intake via central mechanisms. Emerging evidence, however, implicates adipose tissue development and function in the causal relationship between perturbations in FTO expression and obesity. The purpose of this mini review is to shed light on these new studies of FTO function in adipose tissue and present a clearer picture of its impact on obesity susceptibility.
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Affiliation(s)
- Myrte Merkestein
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire OX1 3PT, UK
| | - Dyan Sellayah
- School of Biological Sciences, University of Reading, Reading, Berkshire RG6 6AS, UK
- *Dyan Sellayah:
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21
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Wang P, Xu TY, Wei K, Guan YF, Wang X, Xu H, Su DF, Pei G, Miao CY. ARRB1/β-arrestin-1 mediates neuroprotection through coordination of BECN1-dependent autophagy in cerebral ischemia. Autophagy 2014; 10:1535-48. [PMID: 24988431 PMCID: PMC4206533 DOI: 10.4161/auto.29203] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Autophagy, a highly conserved process conferring cytoprotection against stress, contributes to the progression of cerebral ischemia. β-arrestins are multifunctional proteins that mediate receptor desensitization and serve as important signaling scaffolds involved in numerous physiopathological processes. Here, we show that both ARRB1 (arrestin, β 1) and ARRB2 (arrestin, β 2) were upregulated by cerebral ischemic stress. Knockout of Arrb1, but not Arrb2, aggravated the mortality, brain infarction, and neurological deficit in a mouse model of cerebral ischemia. Accordingly, Arrb1-deficient neurons exhibited enhanced cell injury upon oxygen-glucose deprivation (OGD), an in vitro model of ischemia. Deletion of Arrb1 did not affect the cerebral ischemia-induced inflammation, oxidative stress, and nicotinamide phosphoribosyltransferase upregulation, but markedly suppressed autophagy and induced neuronal apoptosis/necrosis in vivo and in vitro. Additionally, we found that ARRB1 interacted with BECN1/Beclin 1 and PIK3C3/Vps34, 2 major components of the BECN1 autophagic core complex, under the OGD condition but not normal conditions in neurons. Finally, deletion of Arrb1 impaired the interaction between BECN1 and PIK3C3, which is a critical event for autophagosome formation upon ischemic stress, and markedly reduced the kinase activity of PIK3C3. These findings reveal a neuroprotective role for ARRB1, in the context of cerebral ischemia, centered on the regulation of BECN1-dependent autophagosome formation.
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Affiliation(s)
- Pei Wang
- Department of Pharmacology; Second Military Medical University; Shanghai, China
| | - Tian-Ying Xu
- Department of Pharmacology; Second Military Medical University; Shanghai, China
| | - Kai Wei
- Department of Pharmacology; Second Military Medical University; Shanghai, China
| | - Yun-Feng Guan
- Department of Pharmacology; Second Military Medical University; Shanghai, China
| | - Xia Wang
- Department of Pharmacology; Second Military Medical University; Shanghai, China
| | - Hui Xu
- Institute of Biochemistry and Cell Biology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, China
| | - Ding-Feng Su
- Department of Pharmacology; Second Military Medical University; Shanghai, China
| | - Gang Pei
- Institute of Biochemistry and Cell Biology; Shanghai Institutes for Biological Sciences; Chinese Academy of Sciences; Shanghai, China; School of Life Science and Technology; Tongji University; Shanghai, China
| | - Chao-Yu Miao
- Department of Pharmacology; Second Military Medical University; Shanghai, China; Center of Stroke; Beijing Institute for Brain Disorders; Beijing, China
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22
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Merkestein M, McTaggart JS, Lee S, Kramer HB, McMurray F, Lafond M, Boutens L, Cox R, Ashcroft FM. Changes in gene expression associated with FTO overexpression in mice. PLoS One 2014; 9:e97162. [PMID: 24842286 PMCID: PMC4026227 DOI: 10.1371/journal.pone.0097162] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/14/2014] [Indexed: 01/24/2023] Open
Abstract
Single nucleotide polymorphisms in the first intron of the fat-mass-and-obesity-related gene FTO are associated with increased body weight and adiposity. Increased expression of FTO is likely underlying this obesity phenotype, as mice with two additional copies of Fto (FTO-4 mice) exhibit increased adiposity and are hyperphagic. FTO is a demethylase of single stranded DNA and RNA, and one of its targets is the m6A modification in RNA, which might play a role in the regulation of gene expression. In this study, we aimed to examine the changes in gene expression that occur in FTO-4 mice in order to gain more insight into the underlying mechanisms by which FTO influences body weight and adiposity. Our results indicate an upregulation of anabolic pathways and a downregulation of catabolic pathways in FTO-4 mice. Interestingly, although genes involved in methylation were differentially regulated in skeletal muscle of FTO-4 mice, no effect of FTO overexpression on m6A methylation of total mRNA was detected.
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Affiliation(s)
- Myrte Merkestein
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
| | - James S. McTaggart
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
| | - Sheena Lee
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
| | - Holger B. Kramer
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
| | - Fiona McMurray
- Medical Research Council Harwell, Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxford, United Kingdom
| | - Mathilde Lafond
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
| | - Lily Boutens
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
| | - Roger Cox
- Medical Research Council Harwell, Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, Oxford, United Kingdom
| | - Frances M. Ashcroft
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy; and Genetics, University of Oxford, Parks Road, Oxford, United Kingdom
- * E-mail:
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Stratigopoulos G, Martin Carli JF, O'Day DR, Wang L, Leduc CA, Lanzano P, Chung WK, Rosenbaum M, Egli D, Doherty DA, Leibel RL. Hypomorphism for RPGRIP1L, a ciliary gene vicinal to the FTO locus, causes increased adiposity in mice. Cell Metab 2014; 19:767-79. [PMID: 24807221 PMCID: PMC4131684 DOI: 10.1016/j.cmet.2014.04.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 11/11/2013] [Accepted: 04/18/2014] [Indexed: 12/31/2022]
Abstract
Common polymorphisms in the first intron of FTO are associated with increased body weight in adults. Previous studies have suggested that a CUX1-regulatory element within the implicated FTO region controls expression of FTO and the nearby ciliary gene, RPGRIP1L. Given the role of ciliary genes in energy homeostasis, we hypothesized that mice hypomorphic for Rpgrip1l would display increased adiposity. We find that Rpgrip1l⁺/⁻ mice are hyperphagic and fatter, and display diminished suppression of food intake in response to leptin administration. In the hypothalamus of Rpgrip1l⁺/⁻ mice, and in human fibroblasts with hypomorphic mutations in RPGRIP1L, the number of AcIII-positive cilia is diminished, accompanied by impaired convening of the leptin receptor to the vicinity of the cilium, and diminished pStat3 in response to leptin. These findings suggest that RPGRIP1L may be partly or exclusively responsible for the obesity susceptibility signal at the FTO locus.
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Affiliation(s)
- George Stratigopoulos
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
| | - Jayne F Martin Carli
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Diana R O'Day
- Divisions of Developmental Medicine and Genetic Medicine, Department of Pediatrics, Seattle Children's Research Institute and University of Washington 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Liheng Wang
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Charles A Leduc
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Patricia Lanzano
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Wendy K Chung
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Michael Rosenbaum
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Dieter Egli
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | - Daniel A Doherty
- Divisions of Developmental Medicine and Genetic Medicine, Department of Pediatrics, Seattle Children's Research Institute and University of Washington 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Rudolph L Leibel
- Naomi Berrie Diabetes Center and Division of Molecular Genetics, Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
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Zhao Y, Liu XZ, Tian WW, Guan YF, Wang P, Miao CY. Extracellular visfatin has nicotinamide phosphoribosyltransferase enzymatic activity and is neuroprotective against ischemic injury. CNS Neurosci Ther 2014; 20:539-47. [PMID: 24750959 DOI: 10.1111/cns.12273] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/12/2014] [Accepted: 03/26/2014] [Indexed: 12/25/2022] Open
Abstract
AIM Visfatin, a novel adipokine, is predominantly produced by visceral adipose tissue and exists in intracellular and extracellular compartments. The intracellular form of visfatin is proved to be nicotinamide phosphoribosyltransferase (NAMPT) and exhibits neuroprotection through maintaining intracellular NAD(+) pool. However, whether extracellular form of visfatin has NAMPT activity and the effect of extracellular visfatin in cerebral ischemia are unknown. METHODS AND RESULTS Plasma concentrations of visfatin, NAD(+) , and ATP were increased in mice upon cerebral ischemia. Cultured glia, but not neuron, was able to secrete visfatin. Oxygen-glucose deprivation (OGD) stress increased the secretion of visfatin from glia. Extracellular recombinant mouse wild-type visfatin, but not mouse H247A-mutant enzymatic-dead visfatin, had NAMPT enzymatic function in vitro. Treatment of wild-type visfatin, but not H247A-mutant enzymatic-dead visfatin, significantly attenuated detrimental effect of OGD on the cell viability and apoptosis in both cultured mouse neuron and glia. Treatment of neutralizing antibody, abolished the protective effect of extracellular visfatin on cell viability, but failed to block the antiapoptotic effect of extracellular visfatin. At last, we observed that plasma visfatin concentrations decreased in 6-month-old but not 3-month-old SHR-SP compared with that in age-matched Wistar-Kyoto rats. Inhibition of NAMPT enzymatic function of visfatin (by FK866) accelerated the occurrence of stroke in SHR-SP. CONCLUSIONS Extracellular visfatin has NAMPT enzymatic activity and maybe be neuroprotective just as intracellular visfatin in cerebral ischemic injury.
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Affiliation(s)
- Yan Zhao
- Department of Pharmacology, Second Military Medical University, Shanghai, China
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Bravard A, Vial G, Chauvin MA, Rouillé Y, Bailleul B, Vidal H, Rieusset J. FTO contributes to hepatic metabolism regulation through regulation of leptin action and STAT3 signalling in liver. Cell Commun Signal 2014; 12:4. [PMID: 24410832 PMCID: PMC3896784 DOI: 10.1186/1478-811x-12-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/04/2014] [Indexed: 11/10/2022] Open
Abstract
Background The fat mass and obesity associated (FTO) gene is related to obesity and type 2 diabetes, but its function is still largely unknown. A link between leptin receptor-signal transducers and activators of transcription 3 (LepR-STAT3) signalling pathway and FTO was recently suggested in the hypothalamus. Because of the presence of FTO in liver and the role of LepR-STAT3 in the control of hepatic metabolism, we investigated both in vitro and in vivo the potential interrelationship between FTO and LepR-STAT3 signalling pathway in liver and the impact of FTO overexpression on leptin action and glucose homeostasis in liver of mice. Results We found that FTO protein expression is regulated by both leptin and IL-6, concomitantly to an induction of STAT3 tyrosine phosphorylation, in leptin receptor (LepRb) expressing HuH7 cells. In addition, FTO overexpression in vitro altered both leptin-induced Y705 and S727 STAT3 phosphorylation, leading to dysregulation of glucose-6-phosphatase (G6P) expression and mitochondrial density, respectively. In vivo, liver specific FTO overexpression in mice induced a reducetion of Y705 phosphorylation of STAT3 in nuclear fraction, associated with reduced SOCS3 and LepR mRNA levels and with an increased G6P expression. Interestingly, FTO overexpression also induced S727 STAT3 phosphorylation in liver mitochondria, resulting in an increase of mitochondria function and density. Altogether, these data indicate that FTO promotes mitochondrial recruitment of STAT3 to the detriment of its nuclear localization, affecting in turn oxidative metabolism and the expression of leptin-targeted genes. Interestingly, these effects were associated in mice with alterations of leptin action and hyperleptinemia, as well as hyperglycemia, hyperinsulinemia and glucose intolerance. Conclusions Altogether, these data point a novel regulatory loop between FTO and leptin-STAT3 signalling pathways in liver cells, and highlight a new role of FTO in the regulation of hepatic leptin action and glucose metabolism.
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Affiliation(s)
| | | | | | | | | | | | - Jennifer Rieusset
- INSERM U-1060, Laboratoire CarMeN, Université Lyon 1, INRA 1235, INSA de Lyon, Facultés de médecine Charles Mérieux, Lyon-Sud, Oullins, France.
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Li ZY, Zheng SL, Wang P, Xu TY, Guan YF, Zhang YJ, Miao CY. Subfatin is a novel adipokine and unlike Meteorin in adipose and brain expression. CNS Neurosci Ther 2014; 20:344-54. [PMID: 24393292 DOI: 10.1111/cns.12219] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 11/25/2013] [Accepted: 11/29/2013] [Indexed: 12/26/2022] Open
Abstract
AIMS Adipose tissue releases adipokines that play important roles in metabolic and cardio-cerebro-vascular homeostasis. This study was to discover novel adipokines using caloric restriction model. METHODS Adipokine candidates were captured by gene array and bioinformatics analysis and verified by preparation of recombinant protein and antibody. RESULTS We established a potential secreted protein database containing 208 genes and identified a novel adipokine, Subfatin, that was the highest expressed in subcutaneous fat of both rodents and humans among 15 detected tissues. The secreted mammalian Subfatin was a glycosylated protein. Subfatin was located diffusely throughout the adipose tissue except lipid droplets, with comparable expression between adipocytes and stromal cells, but much lower expression in macrophages than adipocytes. Subfatin was downregulated in white adipose tissue of caloric restriction rats, whereas dramatically upregulated during white adipocyte differentiation as well as in white adipose tissue of diet-induced obese mice. Subfatin was annotated as Meteorin-like (Metrnl) in public databases, a similar transcript of Meteorin (Metrn, also known as glial cell differentiation regulator). Meteorin displayed a brain-specific expression and was scarce in various adipose tissues, in contrast to the tissue expression patterns of Subfatin. CONCLUSIONS Subfatin is a novel adipokine regulated by adipogenesis and obesity, with tissue distribution different from its homologue Meteorin.
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Affiliation(s)
- Zhi-Yong Li
- Department of Pharmacology, Second Military Medical University, Shanghai, China
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Abstract
The Fat mass and obesity associated (FTO) gene is a newly identified genetic factor for obesity. However, the exact molecular mechanisms responsible for the effect of FTO on obesity remain largely unknown. Recent studies from genome-wide associated studies reveal that genetic variants in the FTO gene are associated not only with human adiposity and metabolic disorders, but also with cancer, a highly obesity-associated disease as well. Data from animal and cellular models further demonstrate that the perturbation of FTO enzymatic activity dysregulates genes related to energy metabolism, causing the malfunction of energy and adipose tissue homeostasis in mice. The most significant advance about FTO research is the recent discovery of FTO as the first N6-methyl-adenosine (m(6)A) RNA demethylase that catalyzes the m(6)A demethylation in α-ketoglutarate - and Fe(2+)-dependent manners. This finding provides the strong evidence that the dynamic and reversible chemical m(6)A modification on RNA may act as a novel epitranscriptomic marker. Furthermore, the FTO protein was observed to be partially localized onto nuclear speckles enriching mRNA processing factors, implying a potential role of FTO in regulating RNA processing. This review summarizes the recent progress about biological functions of FTO through disease-association studies as well as the data from in vitro and in vivo models, and highlights the biochemical features of FTO that might be linked to obesity.
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Affiliation(s)
- Xu Zhao
- Laboratory of Genome Variations and Precision Biomedicine, Beijing Institute of Genomics, Chinese Academy of Sciences, No. 1-7 Beichen West Road, Chaoyang District, Beijing, 100101, China
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LPS-induced inflammation in the chicken is associated with CCAAT/enhancer binding protein beta-mediated fat mass and obesity associated gene down-regulation in the liver but not hypothalamus. BMC Vet Res 2013; 9:257. [PMID: 24345215 PMCID: PMC3892065 DOI: 10.1186/1746-6148-9-257] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/13/2013] [Indexed: 12/17/2022] Open
Abstract
Background The fat mass and obesity associated gene (FTO) is widely investigated in humans regarding its important roles in obesity and type 2 diabetes. Studies in mammals demonstrate that FTO is also associated with inflammation markers. However, the association of FTO with inflammation in chickens remains unclear. In this study, male chickens on day 28 posthatching were injected intraperitoneally with lipopolysaccharide (LPS) or saline to investigate whether the FTO gene is involved in LPS-induced inflammation. Results We detected significant down-regulation of FTO mRNA in the liver (P < 0.01), but not in the hypothalamus, 2 and 24 h after LPS challenge. Toll-like receptor (TLR) 2 (P < 0.01) and TLR4 (P < 0.01) followed the same pattern as FTO, being suppressed significantly in liver but not in hypothalamus. IL-1β was dramatically up-regulated (P < 0.01) in both liver and hypothalamus 2 h after LPS challenge, while activation of IL-6 was observed in the liver (P < 0.01), but not in hypothalamus. The 5′-flanking sequence of the chicken FTO gene contains nine predicted binding sites for CCAAT/enhancer binding protein beta (C/EBP beta) and one for signal transducer and activator of transcription 3 (STAT3). Significant elevation of C/EBP beta was detected in the liver (P < 0.01), but not in the hypothalamus, 2 h after LPS challenge. Lipopolysaccharide challenge increased the C/EBP beta binding to FTO promoter in the liver (P < 0.01 for fragment 1, P < 0.05 for fragment 2), although the protein content of C/EBP beta was not altered. Moreover, injection of LPS resulted in enhanced phosphorylation of liver STAT3, a downstream transcription factor in IL-6 signaling. Although phosphorylated STAT3 was not detected to directly bind to FTO promoter, it was found to interact with C/EBP beta. Conclusion Our results reveal that FTO expression in liver, but not in hypothalamus, is affected by the i.p. injection of LPS, which may be mediated through tissue-specific FTO transcriptional regulation by C/EBP beta and STAT3 interaction.
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Karmazyn M, Gan XT, Rajapurohitam V. The potential contribution of circulating and locally produced leptin to cardiac hypertrophy and failure. Can J Physiol Pharmacol 2013; 91:883-8. [DOI: 10.1139/cjpp-2013-0057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Leptin is a 16 kDa peptide that was first identified in 1994 through positional cloning of the mouse obesity gene. Although the primary function of leptin is to act a satiety factor through its actions on the hypothalamus, it is now widely recognized that leptin can exert effects on many other organs through activation of its receptors, which are ubiquitously expressed. Leptin is secreted primarily by white adipocytes, but it is also produced by other tissues including the heart where it can exert effects in an autocrine or paracrine manner. One of these effects involves the induction of cardiomyocyte hypertrophy, which appears to occur via multiple cell signalling mechanisms. As adipocytes are the primary site of leptin production, plasma leptin concentrations are generally positively related with body mass index and the degree of adiposity. However, hyperleptinemia is also associated with cardiovascular disease, including heart failure, in the absence of obesity. Here we review the potential role of leptin in heart disease, particularly pertaining to its potential contribution to myocardial remodelling and heart failure, as well as the underlying mechanisms. We further discuss potential interactions between leptin and another adipokine, adiponectin, and the potential implications of this interaction in terms of fully understanding leptin’s effects.
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Affiliation(s)
- Morris Karmazyn
- Department of Physiology and Pharmacology, University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON N6A 5C1, Canada
| | - Xiaohong Tracey Gan
- Department of Physiology and Pharmacology, University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON N6A 5C1, Canada
| | - Venkatesh Rajapurohitam
- Department of Physiology and Pharmacology, University of Western Ontario, Schulich School of Medicine and Dentistry, London, ON N6A 5C1, Canada
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MacKay H, Khazall R, Patterson ZR, Wellman M, Abizaid A. Rats perinatally exposed to food restriction and high-fat diet show differences in adipose tissue gene expression under chronic caloric restriction. Adipocyte 2013; 2:237-45. [PMID: 24052899 PMCID: PMC3774699 DOI: 10.4161/adip.24752] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/12/2013] [Accepted: 04/19/2013] [Indexed: 11/24/2022] Open
Abstract
The aim of this study is to analyze how maternal diet during the lactational period influences the adipose tissue response to chronic caloric restriction in offspring. Lactating dams were subjected to one of three treatments: 50% food restriction (FR), ad lib standard chow (AL), or ad lib high-fat diet (HF). Juveniles were first weaned onto standard chow, then in adulthood 50% calorically restricted and maintained at 90% of normal body weight for 60 d. HF animals showed increased percent body fat compared with AL and FR animals despite equivalent body weights. HF animals showed alterations in the balance of adipose tissue lipogenic (FAS, LPL) and lipolytic (HSL) gene expression that may underlie their propensity to maintain fat stores under caloric restriction.
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Gan XT, Zhao G, Huang CX, Rowe AC, Purdham DM, Karmazyn M. Identification of fat mass and obesity associated (FTO) protein expression in cardiomyocytes: regulation by leptin and its contribution to leptin-induced hypertrophy. PLoS One 2013; 8:e74235. [PMID: 24019958 PMCID: PMC3760875 DOI: 10.1371/journal.pone.0074235] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/31/2013] [Indexed: 11/18/2022] Open
Abstract
The recently-identified fat mass and obesity-associated (FTO) protein is associated with various physiological functions including energy and body weight regulation. Ubiquitously expressed, FTO was identified in heart homogenates although its function is unknown. We studied whether FTO is specifically expressed within the cardiac myocyte and its potential role pertaining to the hypertrophic effect of the adipokine leptin. Most experiments were performed using cultured neonatal rat cardiomyocytes which showed nuclei-specific FTO expression. Leptin significantly increased FTO expression which was associated with myocyte hypertrophy although both events were abrogated by FTO knockdown with siRNA. Administration of a leptin receptor antibody to either normal or obese rats significant reduced myocardial FTO protein expression. Responses in cardiomyocytes were accompanied by JAK2/STAT3 activation whereas JAK2/STAT3 inhibition abolished these effects. Expression of the cut-like homeobox 1(CUX1) transcriptional factor was significantly increased by leptin although this was restricted to the cathepsin L-dependent, proteolytically-derived shorter p110CUX1 isoform whereas the longer p200CUX1 protein was not significantly affected. Cathepsin L expression and activity were both significantly increased by leptin whereas a cathepsin L peptide inhibitor or siRNA specific for CUX1 completely prevented the leptin-induced increase in FTO expression. The cathepsin L peptide inhibitor or siRNA-induced knockdown of either CUX1 or FTO abrogated the hypertrophic response to leptin. Two other pro-hypertrophic factors, endothelin-1 or angiotensin II had no effect on FTO expression and FTO knockdown did not alter the hypertrophic response to either agent. This study demonstrates leptin-induced FTO upregulation in cardiomyocytes via JAK2/STAT3- dependent CUX1 upregulation and suggests an FTO regulatory function of leptin. It also demonstrates for the first time a functional role of FTO in the cardiomyocyte.
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Affiliation(s)
- Xiaohong Tracey Gan
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Ganjian Zhao
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Cathy X. Huang
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Adrianna C. Rowe
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Daniel M. Purdham
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Morris Karmazyn
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
- * E-mail:
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Karra E, O'Daly OG, Choudhury AI, Yousseif A, Millership S, Neary MT, Scott WR, Chandarana K, Manning S, Hess ME, Iwakura H, Akamizu T, Millet Q, Gelegen C, Drew ME, Rahman S, Emmanuel JJ, Williams SCR, Rüther UU, Brüning JC, Withers DJ, Zelaya FO, Batterham RL. A link between FTO, ghrelin, and impaired brain food-cue responsivity. J Clin Invest 2013; 123:3539-51. [PMID: 23867619 DOI: 10.1172/jci44403] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/17/2013] [Indexed: 12/15/2022] Open
Abstract
Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N6-methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO "obesity-risk" rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N6-methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N6-methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans.
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Affiliation(s)
- Efthimia Karra
- Centre for Obesity Research, University College London, London, United Kingdom
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Lin X, Wang Q, Cao Z, Geng M, Cao Y, Liu X. Differential Expression of Wnt Pathway Genes in Sporadic Hepatocellular Carcinomas Infected With Hepatitis B Virus Identified With OligoGE Arrays. HEPATITIS MONTHLY 2013; 13:e6192. [PMID: 23483081 PMCID: PMC3589879 DOI: 10.5812/hepatmon.6192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/05/2012] [Accepted: 07/28/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND Epidemiological evidence has clearly indicated that chronic infection with the hepatitis B virus (HBV) is the major risk factor for developing hepatocellular carcinoma (HCC). Nonetheless, the mechanisms by which HBV contributes to the pathogenesis of HCC have not been fully elucidated. OBJECTIVES Our aim was to characterize differential gene expression profiles related to the Wnt signaling pathway between primary tumor and adjacent normal tissues in HCC patients with concomitant HBVinfection . MATERIALS AND METHODS An oligoGEArray® (an oligonucleotide-based gene expression array platform) containing 126 Wnt signaling pathway-related genes was used to compare gene expressions between primary HCC and adjacent non-tumorous liver tissues from 10 patients with HCC. Selected differential genes were identified with real-time RT-PCR and immunohistochemistry (IHC). In particular, the protein of the differential gene DVL3 (disheveled, dsh homolog 3 [Drosophila]) was chosen to investigate whether it is up regulated in primary tumor correlated with the clinic pathological characteristics of HCC patients. For this purpose we examined 56 HCC tissue samples via IHC for the presence of DVL3 protein. RESULTS Sixteen genes were identified with significant differential expression between HCC and adjacent non-tumorous liver tissue. These genes have been previously associated with the Frizzled signaling pathway, cell cycle, transcription, or protein degradation. All (100%) of the tumor samples results from 56 HCC patients tested were positive for DVL3 via IHC. Based on the intensity of DVL3 immunoreactivity, 25 (44.6%) and 31 (55.4%) of the patients were classified aslow and high-DVL3, respectively, which correlated with tumor stage (P = 0.029). CONCLUSIONS This study clarified a number of Wnt pathway-related genes which are dysregulated in HBV-associated HCC. These genes may be contributedto the frequent activation of the Wnt signaling pathway. Our results promote the role of the Wnt signaling pathway in HBV-associated HCC.
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Affiliation(s)
- Xiaoyan Lin
- Department of Pathology, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Qiangxiu Wang
- Department of Pathology, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Zhixin Cao
- Department of Pathology, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Ming Geng
- Department of Pathology, General Hospital of Jinan Military Command, Jinan, China
| | - Yongcheng Cao
- Department of Pathology, General Hospital of Jinan Military Command, Jinan, China
| | - Xiaohong Liu
- Department of Pathology, General Hospital of Jinan Military Command, Jinan, China
- Corresponding author: Xiaohong Liu, Department of Pathology, General Hospital of Jinan Military Command, 25 Shifan Road, Jinan 250031, China. Tel.: +86-53151666857, Fax: +86-53151666284, E-mail:
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McMurray F, Church CD, Larder R, Nicholson G, Wells S, Teboul L, Tung YCL, Rimmington D, Bosch F, Jimenez V, Yeo GSH, O'Rahilly S, Ashcroft FM, Coll AP, Cox RD. Adult onset global loss of the fto gene alters body composition and metabolism in the mouse. PLoS Genet 2013; 9:e1003166. [PMID: 23300482 PMCID: PMC3536712 DOI: 10.1371/journal.pgen.1003166] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 10/26/2012] [Indexed: 01/27/2023] Open
Abstract
The strongest BMI–associated GWAS locus in humans is the FTO gene. Rodent studies demonstrate a role for FTO in energy homeostasis and body composition. The phenotypes observed in loss of expression studies are complex with perinatal lethality, stunted growth from weaning, and significant alterations in body composition. Thus understanding how and where Fto regulates food intake, energy expenditure, and body composition is a challenge. To address this we generated a series of mice with distinct temporal and spatial loss of Fto expression. Global germline loss of Fto resulted in high perinatal lethality and a reduction in body length, fat mass, and lean mass. When ratio corrected for lean mass, mice had a significant increase in energy expenditure, but more appropriate multiple linear regression normalisation showed no difference in energy expenditure. Global deletion of Fto after the in utero and perinatal period, at 6 weeks of age, removed the high lethality of germline loss. However, there was a reduction in weight by 9 weeks, primarily as loss of lean mass. Over the subsequent 10 weeks, weight converged, driven by an increase in fat mass. There was a switch to a lower RER with no overall change in food intake or energy expenditure. To test if the phenotype can be explained by loss of Fto in the mediobasal hypothalamus, we sterotactically injected adeno-associated viral vectors encoding Cre recombinase to cause regional deletion. We observed a small reduction in food intake and weight gain with no effect on energy expenditure or body composition. Thus, although hypothalamic Fto can impact feeding, the effect of loss of Fto on body composition is brought about by its actions at sites elsewhere. Our data suggest that Fto may have a critical role in the control of lean mass, independent of its effect on food intake. The fat mass and obesity (FTO) gene has one of the strongest links with body mass index (BMI) in the human population. One in six people have the “risk” alteration and weigh 3 kg more than those with the unaltered gene, but it is not understood how this gene influences BMI and obesity. We set out to understand how and where in the body FTO affects food intake, energy expenditure, and body composition using a mouse model that can be manipulated to lack FTO at particular times and/or places. Removing FTO everywhere from conception had a dramatic effect on body composition and resulted in stunted growth and some lethality. Removing FTO everywhere but only in adult animals resulted in better viability and normal growth but, surprisingly, reduced lean mass and increased fat mass with a change in the type of metabolic fuel being used. Finally, we removed FTO from the hypothalamus of adult animals, an important brain region involved in energy metabolism. These animals showed a mild reduction in food intake and weight gain. Our experiments show that FTO has an important role in body composition and that other brain areas outside of the hypothalamus are also important in determining its effects.
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Affiliation(s)
- Fiona McMurray
- MRC Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Chris D. Church
- MRC Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Rachel Larder
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - George Nicholson
- MRC Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Sara Wells
- MRC Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Lydia Teboul
- MRC Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Y. C. Loraine Tung
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Debra Rimmington
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Fatima Bosch
- Center of Animal Biotechnology and Gene Therapy and Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Veronica Jimenez
- Center of Animal Biotechnology and Gene Therapy and Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Giles S. H. Yeo
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Stephen O'Rahilly
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Frances M. Ashcroft
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anthony P. Coll
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Roger D. Cox
- MRC Harwell, Harwell Science and Innovation Campus, Harwell, United Kingdom
- * E-mail:
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LU QIANG, LV GANG, KIM ANDRE, HA JONGMYUNG, KIM SUHKMAN. Expression and clinical significance of extracellular matrix metalloproteinase inducer, EMMPRIN/CD147, in human osteosarcoma. Oncol Lett 2013; 5:201-207. [PMID: 23255920 PMCID: PMC3525466 DOI: 10.3892/ol.2012.981] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/26/2012] [Indexed: 01/15/2023] Open
Abstract
Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. Recent studies have shown that extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) promotes adhesion, invasion and metastasis of malignant tumor cells. The aim of this study was to investigate the impact of EMMPRIN/CD147 expression on prognosis and its correlation with clinicopathological characteristics in patients with osteosarcoma. The expression of EMMPRIN/CD147 in 55 surgical specimens from patients with osteosarcoma at stage IIA or above, 15 non-tumor rib bone tissues, three human osteosarcoma cell lines (Saos-2, U-2OS and MG-63), the human osteoblast cell line HOB and the malignant melanoma cell line A375 were examined by immunohistochemistry, western blot analysis and ELISA, respectively. The potential association of the levels of EMMPRIN/CD147 expression in osteosarcoma specimens with the overall survival of patients was statistically analyzed. We found that the EMMPRIN/CD147 was expressed in 45 out of 55 osteosarcomas, with immunoreactivity primarily within the membrane and cytoplasm of tumor cells, but not in the non-tumor bone tissues. We also observed that EMMPRIN/CD147 was expressed in Saos-2, U-2OS, MG-63 and A375, but not in HOB cells. The levels of EMMPRIN/CD147 expression correlated positively with the pathological degree of osteosarcoma and negatively with the survival period of patients with osteosarcoma. The expression of EMMPRIN/CD147 is a potential factor in the development and prognosis of osteosarcoma and may be a novel therapeutic target of human osteosarcoma.
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Affiliation(s)
- QIANG LU
- Department of Orthopaedics, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001,
P.R. China
| | - GANG LV
- Department of Orthopaedics, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001,
P.R. China
- Correspondence to: Professor Gang Lv, Department of Orthopaedics, The First Affiliated Hospital of China Medical University, No. 155 Nanjing North Street, Heping, Shenyang, Liaoning 110001, P.R. China, E-mail:
| | - ANDRE KIM
- Department of Pharmaceutical Engineering, College of Medical Life Sciences, Silla University, Busan 617-736
| | - JONG-MYUNG HA
- Department of Pharmaceutical Engineering, College of Medical Life Sciences, Silla University, Busan 617-736
| | - SUHKMAN KIM
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735,
Republic of Korea
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Xu TY, Guo LL, Wang P, Song J, Le YY, Viollet B, Miao CY. Chronic exposure to nicotine enhances insulin sensitivity through α7 nicotinic acetylcholine receptor-STAT3 pathway. PLoS One 2012; 7:e51217. [PMID: 23251458 PMCID: PMC3520975 DOI: 10.1371/journal.pone.0051217] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 10/31/2012] [Indexed: 11/18/2022] Open
Abstract
This study was to investigate the effect of nicotine on insulin sensitivity and explore the underlying mechanisms. Treatment of Sprague-Dawley rats with nicotine (3 mg/kg/day) for 6 weeks reduced 43% body weight gain and 65% blood insulin level, but had no effect on blood glucose level. Both insulin tolerance test and glucose tolerance test demonstrated that nicotine treatment enhanced insulin sensitivity. Pretreatment of rats with hexamethonium (20 mg/kg/day) to antagonize peripheral nicotinic receptors except for α7 nicotinic acetylcholine receptor (α7-nAChR) had no effect on the insulin sensitizing effect of nicotine. However, the insulin sensitizing effect but not the bodyweight reducing effect of nicotine was abrogated in α7-nAChR knockout mice. Further, chronic treatment with PNU-282987 (0.53 mg/kg/day), a selective α7-nAChR agonist, significantly enhanced insulin sensitivity without apparently modifying bodyweight not only in normal mice but also in AMP-activated kinase-α2 knockout mice, an animal model of insulin resistance with no sign of inflammation. Moreover, PNU-282987 treatment enhanced phosphorylation of signal transducer and activator of transcription 3 (STAT3) in skeletal muscle, adipose tissue and liver in normal mice. PNU-282987 treatment also increased glucose uptake by 25% in C2C12 myotubes and this effect was total abrogated by STAT3 inhibitor, S3I-201. All together, these findings demonstrated that nicotine enhanced insulin sensitivity in animals with or without insulin resistance, at least in part via stimulating α7-nAChR-STAT3 pathway independent of inflammation. Our results contribute not only to the understanding of the pharmacological effects of nicotine, but also to the identifying of new therapeutic targets against insulin resistance.
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Affiliation(s)
- Tian-Ying Xu
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Ling-Ling Guo
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Pei Wang
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Jie Song
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Ying-Ying Le
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Benoit Viollet
- Institut Cochin, Université Paris Descartes, CNRS (UMR8104), Paris, France
- Inserm, U567, Paris, France
| | - Chao-Yu Miao
- Department of Pharmacology, Second Military Medical University, Shanghai, China
- * E-mail:
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Zou YX, Zhang XH, Su FY, Liu X. Importance of riboflavin kinase in the pathogenesis of stroke. CNS Neurosci Ther 2012; 18:834-40. [PMID: 22925047 DOI: 10.1111/j.1755-5949.2012.00379.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 06/07/2012] [Accepted: 06/15/2012] [Indexed: 11/28/2022] Open
Abstract
AIMS To explore risk factors for stroke independent of hypertension and the relationship between riboflavin kinase (RFK) and stroke. METHODS Gene expression profiling in the brains of spontaneously hypertensive rats (SHR) and stroke-prone spontaneously hypertensive rats (SHRSP) was comparatively analyzed by gene chips. The differentially expressed gene RFK was further verified by q-PCR and Western blot. The protective role of RFK-regulated flavins (including riboflavin, flavin mononucleotide, and flavin adenine dinucleotide) in stroke was observed in middle cerebral artery occlusion (MCAO) mice. Influence of flavins on apoptosis and death in oxygen and glucose deprivation (OGD)-treated neurons was examined by flow cytometry. Bax and Bcl-2 proteins were detected by Western blot. RESULTS Of the 76 differentially expressed genes, 41 genes were upregulated, and 35 genes were downregulated in SHRSP as compared with SHR. RFK was significantly downregulated in SHRSP. Flavins markedly decreased infarct area in MCAO mice, inhibited apoptosis and death in OGD-treated neurons, and decreased Bax protein expression. CONCLUSIONS Physiological downregulation of RFK may be a new potential risk factor for stroke, which probably affects the absorbance and utility of riboflavin and further destroys the protective effect of flavins on stroke. RFK might act as a therapeutic target for stroke.
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Affiliation(s)
- Ying-Xin Zou
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai, China
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Wang P, Tian WW, Song J, Guan YF, Miao CY. Deficiency of NG2+ cells contributes to the susceptibility of stroke-prone spontaneously hypertensive rats. CNS Neurosci Ther 2012; 17:327-32. [PMID: 21951366 DOI: 10.1111/j.1755-5949.2011.00265.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
AIMS The purpose of this study is to investigate whether the NG2(+) cells, a class of oligodendrocyte progenitor cells, is involved in the pathophysiology of stroke in stroke-prone spontaneously hypertensive rat (SHR-SP). METHODS SHR-SP, SHR, Wistar-Kyoto rats (WKY), and C57BJ/6 mice were used. Immunohistochemistry was conducted to evaluate the number of NG2(+) cells in frozen brain sections. Demyelination was evaluated by Sudan black staining and serum level of myelin basic protein. Middle cerebral artery occlusion (MCAO) was performed to prepare experimental stroke model. RESULTS The number of NG2(+) cells was significantly decreased in infarct core and increased in penumbra in WKY rats after MCAO. In brain sections of 6-month-old SHR-SP, the number of NG2(+) cells was significantly (P < 0.01) less than that in age-matched SHR and WKY rats. However, this phenomenon was not observed in 3-month-old rats. Demyelination was found in 6-month-old SHR-SP but not in 3-month-old SHR-SP. Pharmacological treatment of cuprizone in mice induced demyelination and enlargement of cerebral infarction after MCAO. CONCLUSION The decline of NG2(+) cells may cause demyelination and contribute to the susceptibility of SHR-SP to ischemic brain injury.
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Affiliation(s)
- Pei Wang
- Department of Pharmacology, Second Military Medical University, Shanghai, China
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Wang P, Zhang RY, Song J, Guan YF, Xu TY, Du H, Viollet B, Miao CY. Loss of AMP-activated protein kinase-α2 impairs the insulin-sensitizing effect of calorie restriction in skeletal muscle. Diabetes 2012; 61:1051-61. [PMID: 22396207 PMCID: PMC3331748 DOI: 10.2337/db11-1180] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Whether the well-known metabolic switch AMP-activated protein kinase (AMPK) is involved in the insulin-sensitizing effect of calorie restriction (CR) is unclear. In this study, we investigated the role of AMPK in the insulin-sensitizing effect of CR in skeletal muscle. Wild-type (WT) and AMPK-α2(-/-) mice received ad libitum (AL) or CR (8 weeks at 60% of AL) feeding. CR increased the protein level of AMPK-α2 and phosphorylation of AMPK-α2. In WT and AMPK-α2(-/-) mice, CR induced comparable changes of body weight, fat pad weight, serum triglycerides, serum nonesterified fatty acids, and serum leptin levels. However, decreasing levels of fasting/fed insulin and fed glucose were observed in WT mice but not in AMPK-α2(-/-) mice. Moreover, CR-induced improvements of whole-body insulin sensitivity (evidenced by glucose tolerance test/insulin tolerance test assays) and glucose uptake in skeletal muscle tissues were abolished in AMPK-α2(-/-) mice. Furthermore, CR-induced activation of Akt-TBC1D1/TBC1D4 signaling, inhibition of mammalian target of rapamycin-S6K1-insulin receptor substrate-1 pathway, and induction of nicotinamide phosphoribosyltransferase-NAD(+)-sirtuin-1 cascade were remarkably impaired in AMPK-α2(-/-) mice. CR serum increased stability of AMPK-α2 protein via inhibiting the X chromosome-linked ubiquitin-specific protease 9-mediated ubiquitylation of AMPK-α2. Our results suggest that AMPK may be modulated by CR in a ubiquitylation-dependent manner and acts as a chief dictator for the insulin-sensitizing effects of CR in skeletal muscle.
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Affiliation(s)
- Pei Wang
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Ruo-Yu Zhang
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Jie Song
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Yun-Feng Guan
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Tian-Ying Xu
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Hui Du
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Benoit Viollet
- Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique (Unité Mixte de Recherche 8104), Paris, France
- INSERM U1016, Paris, France
| | - Chao-Yu Miao
- Department of Pharmacology, Second Military Medical University, Shanghai, China
- Corresponding author: Chao-Yu Miao, , or Pei Wang,
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Celecoxib inhibits growth of human autosomal dominant polycystic kidney cyst-lining epithelial cells through the VEGF/Raf/MAPK/ERK signaling pathway. Mol Biol Rep 2012; 39:7743-53. [PMID: 22415852 PMCID: PMC3358558 DOI: 10.1007/s11033-012-1611-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 01/24/2012] [Indexed: 12/13/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a progressive chronic kidney disease. To date there are no effective medicines to halt development and growth of cysts. In the present study, we explored novel effects of celecoxib (CXB), a COX-2 specific inhibitor, on primary cultures of human ADPKD cyst-lining epithelial cells. Primary cultures of ADPKD cyst-lining epithelial cells were obtained from five patients. Effects of CXB were measured by various assays to detect BrdU incorporation, apoptosis and proliferation in vitro. Additionally, effects of CXB on kidney weight, the cyst index, the fibrosis index, blood urea nitrogen (BUN), serum creatinine (SCr), serum 6-keto-PGF-1α, serum thromboxane-2 (TXB2) and renal PCNA expression were assessed in Han:SPRD rat, a well-characterized rodent model of PKD. CXB inhibited proliferation of ADPKD cyst-lining epithelial cells, blocked the release of VEGF from the cells and induced extensive apoptosis in a time- and dose-dependent manner. Moreover, CXB up-regulated the cell cycle negative regulator p21CIP/WAF1 and the cell cycle positive regulator Cyclin A, blocked ERK1/2 phosphorylation, induced apoptotic factors (Bax and caspase-3) and reduced Bcl-2. Furthermore, CXB inhibited the expression of VEGFR-2 and Raf-1 in ADPKD cyst-lining epithelial cells. CXB markedly reduced the cyst index, the fibrosis index, leukocyte infiltration, BUN, SCr, serum 6-keto-PGF-1α, TXB2 and renal PCNA expression in Han:SPRD rat. We demonstrated for the first time that CXB could suppress renal cyst-lining growth both in vitro and in vivo in Han:SPRD rat. CXB can inhibit proliferation, suppress cell cycle progression, and induce apoptosis in ADPKD cyst-lining epithelial cells through the inhibition of the VEGF/VEGFR-2/Raf-1/MAPK/ERK signaling pathway.
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Wang B, Wang W, Li F, Wang Z, Ma J, Zhao G. Qidantongmai protects endothelial cells against hypoxia-induced damage through regulating the serum VEGF-a level. AFRICAN JOURNAL OF TRADITIONAL, COMPLEMENTARY, AND ALTERNATIVE MEDICINES 2012; 9:210-20. [PMID: 23983337 DOI: 10.4314/ajtcam.v9i2.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Qidantongmai (QDTM) is a Traditional Chinese Medicine (TCM) preparation that has long been used in folk medicine for the treatment of cardiovascular diseases. However, the underlying mechanisms are poorly understood. The present study was designed to determine the effects of QDTM on endothelial cells under hypoxic conditions both in vitro and in vivo. Primary human umbilical vein endothelial cells (HUVECs) were isolated, pretreated with QDTM medicated serum or saline control, and then cultured under hypoxia (2% oxygen) for 24 h. Sprague-Dawley rats were administered 1 ml/100 g of QDTM or saline twice a day for 4 days and treated with hypoxia (6 hours/day, discontinuous hypoxia, 360 mm Hg). QDTM not only protected HUVECs from hypoxia-induced damage by significantly retaining cell viability (P < 0.05) and decreasing apoptosis (P < 0.05) in vitro, but also protected liver endothelial cells from hypoxia-induced damage in vivo. Moreover, QDTM increased the serum VEGF-A level (P < 0.05) in rats treated with hypoxia for 7 days but suppressed the upregulation of serum VEGF-A in rats treated with hypoxia for 14 days. QDTM is a potent preparation that can protect endothelial cells against hypoxia-induced damage. The ability of QDTM to modulate the serum VEGF-A level may play an important role in its effects on endothelial cells.
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Affiliation(s)
- Bing Wang
- Department of Traditional Chinese Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shanxi 710032, People's Republic of China
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McTaggart JS, Lee S, Iberl M, Church C, Cox RD, Ashcroft FM. FTO is expressed in neurones throughout the brain and its expression is unaltered by fasting. PLoS One 2011; 6:e27968. [PMID: 22140494 PMCID: PMC3227617 DOI: 10.1371/journal.pone.0027968] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 10/28/2011] [Indexed: 11/20/2022] Open
Abstract
Single-nucleotide polymorphisms in the first intron of the ubiquitously expressed FTO gene are associated with obesity. Although the physiological functions of FTO remain unclear, food intake is often altered when Fto expression levels are manipulated. Furthermore, deletion of FTO from neurones alone has a similar effect on food intake to deletion of FTO in all tissues. These results indicate that FTO expression in the brain is particularly important. Considerable focus has been placed on the dynamic regulation of Fto mRNA expression in the hypothalamus after short-term (16–48 hour) fasting, but results have been controversial. There are no studies that quantify FTO protein levels across the brain, and assess its alteration following short-term fasting. Using immunohistochemistry, we found that FTO protein is widely expressed in mouse brain, and present in the majority of neurones. Using quantitative Western blotting and RT-qPCR we show that FTO protein and mRNA levels in the hypothalamus, cerebellum and rostral brain are relatively uniform, and levels in the brain are higher than in skeletal muscles of the lower limbs. Fasting for 18 hours does not alter the expression pattern, or levels, of FTO protein and mRNA. We further show that the majority of POMC neurones, which are critically involved in food intake regulation, also express FTO, but that the percentage of FTO-positive POMC neurones is not altered by fasting. In summary, we find no evidence that Fto/FTO expression is regulated by short-term (18-hour) fasting. Thus, it is unlikely that the hunger and increased post-fasting food intake caused by such food deprivation is driven by alterations in Fto/FTO expression. The widespread expression of FTO in neurones also suggests that physiological studies of this protein should not be limited to the hypothalamus.
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Affiliation(s)
- James S. McTaggart
- Department of Physiology, Anatomy and Genetics, OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
| | - Sheena Lee
- Department of Physiology, Anatomy and Genetics, OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
| | - Michaela Iberl
- Department of Physiology, Anatomy and Genetics, OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
| | - Chris Church
- OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- MRC Harwell, Metabolism and Inflammation, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Roger D. Cox
- OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- MRC Harwell, Metabolism and Inflammation, Harwell Science and Innovation Campus, Harwell, United Kingdom
| | - Frances M. Ashcroft
- Department of Physiology, Anatomy and Genetics, OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- OXION Centre for Ion Channel Studies, Henry Wellcome Centre for Gene Function, Oxford, United Kingdom
- * E-mail:
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Choquet H, Meyre D. Genetics of Obesity: What have we Learned? Curr Genomics 2011; 12:169-79. [PMID: 22043165 PMCID: PMC3137002 DOI: 10.2174/138920211795677895] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 03/31/2011] [Accepted: 03/31/2011] [Indexed: 12/14/2022] Open
Abstract
Candidate gene and genome-wide association studies have led to the discovery of nine loci involved in Mendelian forms of obesity and 58 loci contributing to polygenic obesity. These loci explain a small fraction of the heritability for obesity and many genes remain to be discovered. However, efforts in obesity gene identification greatly modified our understanding of this disorder. In this review, we propose an overlook of major lessons learned from 15 years of research in the field of genetics and obesity. We comment on the existence of the genetic continuum between monogenic and polygenic forms of obesity that pinpoints the role of genes involved in the central regulation of food intake and genetic predisposition to obesity. We explain how the identification of novel obesity predisposing genes has clarified unsuspected biological pathways involved in the control of energy balance that have helped to understand past human history and to explore causality in epidemiology. We provide evidence that obesity predisposing genes interact with the environment and influence the response to treatment relevant to disease prediction.
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Affiliation(s)
- Hélène Choquet
- Ernest Gallo Clinic and Research Center, Department of Neurology, University of California, San Francisco, Emeryville, California 94608, USA
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Abstract
Objective: Recent genome-wide association studies have identified a strong association between obesity and common variants in the fat mass and obesity associated (FTO) gene. FTO has been detected in the hypothalamus, but little is known about its regulation in that particular brain structure. The present study addressed the hypothesis that hypothalamic FTO expression is regulated by nutrients, specifically by glucose, and that its regulation by nutrients is impaired in obesity. Research design and methods: The effect of intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) administration of glucose on hypothalamic Fto mRNA levels was examined in fasted mice. Additionally, the effect of glucose on Fto mRNA levels was also investigated ex vivo using mouse hypothalamic explants. Lastly, the effect of i.p. glucose injection on hypothalamic Fto immunoreactivity and food intake was compared between lean wild-type and obese ob/ob mice. Results: In wild-type mice, fasting reduced both Fto mRNA levels and the number of Fto-immunoreactive cells in the hypothalamus, whereas i.p. glucose treatment reversed this effect of fasting. Furthermore, i.c.v. glucose treatment also increased hypothalamic Fto mRNA levels in fasted mice. Incubation of hypothalamic explants at high glucose concentration increased Fto mRNA levels. In ob/ob mice, both fasting and i.p. glucose treatment failed to alter the number of Fto-immunoreactive cells in the hypothalamus. Glucose-induced feeding suppression was abolished in ob/ob mice. Conclusion: Reduction in hypothalamic Fto expression after fasting likely arises at least partly from reduced circulating glucose levels and/or reduced central action of glucose. Obesity is associated with impairments in glucose-mediated regulation of hypothalamic Fto expression and anorexia. Hypothalamic Fto-expressing neurons may have a role in the regulation of metabolism by monitoring metabolic states of the body.
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