miR-24-3p regulates CDX2 during intestinalization of cardiac-type epithelium in a human model of Barrett's esophagus.

BACKGROUND: Cardiac-type epithelium has been proposed as the precursor of intestinal metaplasia in the development of Barrett's esophagus. Dysregulation of microRNAs (miRNAs) and their effects on CDX2 expression may contribute to intestinalization of cardiac-type epithelium. The aim of this study was to examine the possible effect of specific miRNAs on the regulation of CDX2 in a human model of Barrett's esophagus. METHODS: Microdissection of cardiac-type glands was performed in biopsy samples from patients who underwent esophagectomy and developed cardiac-type epithelium in the remnant esophagus. OpenArray™ analysis was used to compare the miRNAs profiling of cardiac-type glands with negative or fully positive CDX2 expression. CDX2 was validated as a miR-24 messenger RNA target by the study of CDX2 expression upon transfection of miRNA mimics and inhibitors in esophageal adenocarcinoma cell lines. The CDX2/miR-24 regulation was finally validated by in situ miRNA/CDX2/MUC2 co-expression analysis in cardiac-type mucosa samples of Barrett's esophagus. RESULTS: CDX2 positive glands were characterized by a unique miRNA profile with a significant downregulation of miR-24-3p, miR-30a-5p, miR-133a-3p, miR-520e-3p, miR-548a-1, miR-597-5p, miR-625-3p, miR-638, miR-1255b-1, and miR-1260a, as well as upregulation of miR-590-5p. miRNA-24-3p was identified as potential regulator of CDX2 gene expression in three databases and confirmed in esophageal adenocarcinoma cell lines. Furthermore, miR-24-3p expression showed a negative correlation with the expression of CDX2 in cardiac-type mucosa samples with different stages of mucosal intestinalization. CONCLUSION: These results showed that miRNA-24-3p regulates CDX2 expression, and the downregulation of miRNA-24-3p was associated with the acquisition of the intestinal phenotype in esophageal cardiac-type epithelium.

Targeting the circulating microRNA signature of obesity.

BACKGROUND: Genomic studies have yielded important insights into the pathogenesis of obesity. Circulating microRNAs (miRNAs) are valuable biomarkers of systemic 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 patients. 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 associated with anthropometric variables in the initial sample. RESULTS: In the validation study, morbidly obese patients 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 targets leukemia inhibitory factor receptor (LIFR) and transforming growth factor receptor (TGFR) of miR-140-5p, miR-142-3p, miR-15a, and miR-520c-3p circulated in association with their corresponding miRNAs. Moreover, a discriminant function of 3 miRNAs (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.

Time course of changes in the expression of insulin sensitivity-related genes after an acute load of virgin olive oil.

Our aim was to examine whether an acute fat load could induce changes in the expression of insulin sensitivity-related genes in human peripheral blood mononuclear cells. Selection of candidate genes was based on previous studies with sustained virgin olive oil (VOO) consumption and biological plausibility in relation to insulin sensitivity. Eleven healthy volunteers ingested raw VOO (50 mL). Blood samples were collected at 0, 1 and 6 h. Plasma glucose, insulin and hydroxytyrosol increased at 1 h and decreased at 6 h. Lipid oxidative damage increased at 6 h (p < 0.05). Gene expression changes were characterized based on quantification of the samples relative to a reference sample [i.e., relative quantification (RQ) method]. A 1 h downregulation was observed in O-linked-N-acetylglucosamine transferase (OGT, RQ: 0.62 +/- 0.32) and arachidonate-5-lipoxygenase-activating protein (ALOX5AP, RQ: 0.64 +/- 0.31) genes (p < 0.005). OGT was upregulated at 6 h (RQ: 1.88 +/- 0.28, p < 0.05). CD36 (thrombospondin receptor) was upregulated at 1 h (RQ: 1.6 +/- 0.8, p < 0.05) returning to the basal values at 6 h. Lipoic acid synthetase (LIAS), peroxisome proliferator-activated receptor binding protein (PPARBP), a disintegrin and metallopeptidase domain 17 (ADAM17), and adrenergic beta-2-receptor (ADRB2) genes were upregulated at 6 h (range for the mean RQ: 1.33-1.56) following an increasing linear trend (p < 0.05) from baseline to 6 h. ALOX5AP and OGT genes inversely correlated with insulin and glucose levels at 1 h. ADAM17 and ADRB2 inversely correlated with oxLDL at 6 h (p < 0.05). Taken together, these observations may inform the future clinical nutrigenomics study designs and indicate that a single dose of VOO can elicit quantifiable and rapid changes in gene expression in targets that are mechanistically relevant for insulin sensitivity and the metabolic syndrome.

Interrelationship of smoking, paraoxonase activity, and leisure time physical activity: a population-based study.

METHODS: We determined the effect of smoking on PON1 activity levels in a population-based sample of 1380 subjects and examined the possibility of regular physical activity modulating the effect of cigarette smoking on PON1 activity levels at a population level. RESULTS: Mean PON1 activity was significantly lower in smokers than in non- or ex-smokers (237.6+/-8.4 vs. 276.7+/-5.3 U/l, mean+/-S.E.M.; P= 0.001). PON1 activity levels were significantly higher in physically active subjects than in those who were inactive (296.1+/-10.4 vs. 260.1+/-9.2 U/l; P=0.002). Inactive smokers showed significantly lower PON1 activity levels than inactive nonsmokers (P=0.002). These differences disappeared when active nonsmokers were compared with active smokers. Serum PON1 activity levels were found to be significantly increased in active smokers compared to those in inactive smokers. A statistically significant interaction (P=0.003) between smoking and physical activity on PON1 activity was observed. CONCLUSION: Smoking appears to have a deleterious effect on PON1 activity levels. Being physically active clearly attenuates this effect.

Paraoxonase1-192 polymorphism modulates the effects of regular and acute exercise on paraoxonase1 activity.

Regular exercise practise is a protective factor against coronary heart disease and enhances antioxidant systems, whereas acute exercise appears to be a major source of increased oxidative stress. Paraoxonase1 (PON1) is an antioxidant HDL-linked enzyme, whose activity toward paraoxon (PON1 activity) is strongly modulated by the PON1-192 polymorphism, comprising Q and R alleles for low and high PON1 activity, respectively. Another polymorphism at the PON1 locus, the PON1-55, modulates PON1 protein and activity levels. PON1 activity, lipid levels, and oxidized LDL concentration were determined in 17 healthy young volunteers before and after a 16-weeks aerobic exercise training period. Furthermore, PON1 activity was analyzed after a bout of exercise in both situations. We found that regular exercise was associated with a decrease in oxidized LDL levels, and an increase in PON1 activity in QQ subjects and with a decrease in PON1 activity in R carriers. A bout of exercise produced an increase in PON1 activity just after the bout of exercise, followed by a decrease in its activity. A recovery of the basal PON1 activity levels at 24 h was found in QQ subjects regardless of their training status and in trained R carriers, but not in untrained R carriers. These results suggest that the effects of regular and acute exercise on PON1 activity levels are modulated by PON1-192 polymorphism. Changes were less evident for the PON1-55 polymorphism.