Targeting the Circulating MicroRNA Signature of Obesity Francisco Jose ´ Ortega, 1,2 Josep Marı´a Mercader, 3 Victoria Catala ´ n, 2,4 Jose ´ Marı´aMoreno-Navarrete, 1,2 Neus Pueyo, 1,2 Mo ´ nica Sabater, 1 Javier Go ´ mez-Ambrosi, 2,4 Roger Anglada, 5 Jose ´ Antonio Ferna ´ ndez-Formoso, 2 Wifredo Ricart, 1,2 Gema Fru ¨ hbeck, 2,4 and Jose ´ Manuel Ferna ´ ndez-Real 1,2* BACKGROUND: Genomic studies have yielded important insights into the pathogenesis of obesity. Circulating microRNAs (miRNAs) are valuable biomarkers of sys- temic diseases and potential therapeutic targets. We sought to define the circulating pattern of miRNAs in obesity and examine changes after weight loss. METHODS: We assessed the genomewide circulating miRNA profile cross-sectionally in 32 men and after surgery-induced weight loss in 6 morbidly obese pa- tients. The most relevant miRNAs were cross- sectionally validated in 80 men and longitudinally in 22 patients (after surgery-induced weight loss). We evaluated the effects of diet-induced weight loss in 9 obese patients. Thirty-six circulating miRNAs were as- sociated with anthropometric variables in the initial sample. RESULTS: In the validation study, morbidly obese pa- tients showed a marked increase of miR-140-5p, miR- 142-3p (both P  0.0001), and miR-222 (P = 0.0002) and decreased levels of miR-532–5p, miR-125b, miR- 130b, miR-221, miR-15a, miR-423-5p, and miR- 520c-3p (P  0.0001 for all). Interestingly, in silico tar- gets leukemia inhibitory factor receptor (LIFR) and transforming growth factor receptor (TGFR) of miR- 140-5p, miR-142-3p, miR-15a, and miR-520c-3p cir- culated in association with their corresponding miRNAs. Moreover, a discriminant function of 3 miR- NAs (miR-15a, miR-520c-3p, and miR-423-5p) was specific for morbid obesity, with an accuracy of 93.5%. Surgery-induced (but not diet-induced) weight loss led to a marked decrease of miR-140-5p, miR-122, miR- 193a-5p, and miR-16-1 and upregulation of miR-221 and miR-199a-3p (P  0.0001 for all). CONCLUSIONS: Circulating miRNAs are deregulated in severe obesity. Weight loss–induced changes in this profile and the study of in silico targets support this observation and suggest a potential mechanistic relevance. © 2013 American Association for Clinical Chemistry Obesity is a well-known epidemic health problem worldwide. Obese patients suffer from decreased life quality and expectancy, as well as increased risk of type 2 diabetes, cardiovascular disease, hepatic steatosis, and cancer (1). Body composition is likely determined by genetic makeup in close relationship with behav- ioral and environmental factors. The intake of energy- dense foods, especially combined with reduced physi- cal activity, contributes to the high prevalence of obesity. However, the existence of complex systems that regulate energy balance calls for a broader view of this paradigm (2). Extensive efforts are being made to identify obesity-affecting genes to better understand pathogen- esis, find new targets for clinical therapy, and allow early prediction of metabolic complications. Cur- rently, new tools such as high-throughput technologies for genomic analyses may solve common problems in clinical practice, allowing earlier and more accurate di- agnosis of comorbidities and improving prediction and response to therapy (3). MicroRNAs (miRNAs) 6 are small, noncoding, highly conserved RNAs. Since the discovery of miRNAs in 1993, their expression profiles and functions have been extensively studied. Through modifying mRNA availability and protein synthesis, miRNAs regulate many cellular processes such as cell growth, prolifera- 1 Department of Diabetes, Endocrinology and Nutrition, Institut d’Investigacio ´ Biome ´ dica de Girona, Girona, Spain; 2 Centro de Investigacio ´ n Biome ´ dica en Red de la Fisiopatologı ´a de la Obesidad y la Nutricio ´ n (CB06/03) and Instituto de Salud Carlos III, Santiago de Compostela, Spain; 3 Joint Institute for Research in Biomedicine-Barcelona Supercomputing Center Program on Computational Biology, Barcelona, Spain; 4 Metabolic Research Laboratory, Clı ´nica Universidad de Navarra, Pamplona, Spain; and 5 Genome Facility Core Service, Universitat Pompeu Fabra, Barcelona, Spain. * Address correspondence to this author at: Section of Diabetes, Endocrinol- ogy and Nutrition, Hospital of Girona “Dr Josep Trueta,” Carretera de Franc ¸a s/n, 17007, Girona, Spain. Fax +34-972-94-02-70; e-mail jmfreal@ idibgi.org. Received September 13, 2012; accepted January 4, 2013. Previously published online at DOI: 10.1373/clinchem.2012.195776 6 Nonstandard abbreviations: miRNA, microRNA; BMI, body mass index; LIFR, leukemia inhibitory factor receptor; VEGFA, vascular endothelial growth factor A; RT, reverse transcription; Ct, thermal cycle; TGFBR1, transforming growth factor- receptor; JAK-STAT, Janus kinase signal transducer and activator of transcription; MAPK, mitogen-activated protein kinase. Clinical Chemistry 59:5 781–792 (2013) Endocrinology and Metabolism 781 Downloaded from https://academic.oup.com/clinchem/article/59/5/781/5622174 by guest on 06 July 2022