Ewa Ocłoń

Hyperglycemia-induced changes in miRNA expression patterns in epicardial adipose tissue of piglets

MicroRNAs (miRNAs) are a class of molecular posttranscriptional regulators found to participate in numerous biological mechanisms, such as adipogenesis, fat deposition, or glucose metabolism. Additionally, a detailed analysis on the molecular and cellular mechanisms of miRNA-related effects on metabolism leads to developing novel diagnostic markers and therapeutic approaches. To identify miRNA whose activity changed in epicardial adipose tissue in piglets during hyperglycemia, we analyzed the different miRNA expression patterns between control and hyperglycemia groups. The microarray analysis selected three differentially expressed microRNAs as potential biomarkers: hsa-miR-675-5p, ssc-miR-193a-3p, and hsa-miR-144-3p. The validation of miRNA expression with real-time PCR indicated an increased expression levels of ssc-miR-193a-3p and miR-675-5p, whereas the expression level of hsa-miR-144-3p was lower in epicardial adipose tissue in response to hyperglycemia (P<0.01). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses suggested that these miRNAs differentially expressed between hyperglycemic and control piglets are involved in insulin, adipocytokine, and phosphatidylinositol 3-kinase-Akt signaling pathways, and development of type 2 diabetes as well. The results suggested that hyperglycemia can significantly affect the expression patterns of miRNA in porcine adipose tissue.

Hyperglycemia-induced changes in resistin gene expression in white adipose tissue in piglets

Abstract Previous data strongly indicated that resistin, an adipocyte-derived signalling peptide, plays an important role in metabolism and glucose homeostasis. Thus, the aim of the present study was to examine changes in synthesis and concentration of resistin in white adipose tissue in response to hyperglycemia in piglets. In order to develop hyperglycemia, piglets (10-week-old, Polish Landrace fatteners, female) received intraperitoneal (ip) injection of 150 mg streptozotocin (HI, n=6) or 60 mg synthetic glucocorticoid (HII, n=6). An injection of NaCl physiological saline was used as a control (n=6). Plasma resistin level was significantly higher in HII group compared with the control, while no difference was observed in HI. In epicardial adipose tissue (EAT ) the resistin mRNA level significantly increased whereas the opposite effect was observed for omental fat tissue (OAT ) in both experimental groups. Additionally, the resistin concentration did not change in EAT ; however, it was decreased in omental adipose tissue in response to hyperglycemia. The results obtained indicate that activity of resistin strongly depends on glycemic status as well as adipose tissue localization.