Comparison of long non-coding RNAs in adipose and muscle tissues between seven indigenous Chinese and the Yorkshire pig breeds.

lncRNAs play crucial roles in fat metabolism in animals. Previously, we have compared the mRNA transcriptome profiles between seven fat-type Chinese pig breeds and one lean-type Western breed (Yorkshire, YY). The associations between differentially expressed (DE) genes and phenotypical traits were investigated. In the present study, to further explore the underlying regulatory mechanisms, lncRNAs were sequenced and compared between YY and Chinese indigenous breeds. The results showed 9114 and 7538 DE lncRNAs between at least one Chinese breed and the YY breed in the adipose and muscle tissue respectively. KEGG enrichment analysis revealed that the target genes of these DE lncRNAs mainly influenced the glucolipid metabolism, which is an important process affecting meat quality. Correlation analyses between the DE lncRNA and DE mRNA genes related to meat quality and growth traits were performed. The results showed that LTCONS_00073280 was associated with intramuscular fat content. Four lncRNAs (LTCONS_00101781, LTCONS_00037879, LTCONS_00088260 and LTCONS-00128343) might mediate backfat thickness. Overall, this study provides candidate lncRNAs that potentially affect meat quality, which might be useful for molecular breeding of pig breeds in future.

Developmental changes in the expression of the GLUT2 and GLUT4 genes in the longissimus dorsi muscle of Yorkshire and Tibetan pigs.

Glucose transporter proteins 2 and 4 (GLUT2 and GLUT4) play important roles in glucose transport and energy metabolism. Changes in the levels of GLUT2 and GLUT4 mRNA were measured in longissimus dorsi muscle from the lean Yorkshire and fat Tibetan pig breeds at six different time points (1, 2, 3, 4, 5, and 6 months) with quantitative real-time polymerase chain reactions. The results showed that GLUT2 and GLUT4 mRNA were abundantly expressed in the longissimus dorsi muscle and that the developmental expression patterns were similar in both breeds. Tibetan pigs exhibited higher intramuscular fat and GLUT2 mRNA levels, while Yorkshire pigs exhibited a higher myofiber cross-sectional area (CSA) and GLUT4 mRNA levels. Furthermore, the changes in the GLUT4 mRNA levels were strongly and positively correlated with the CSA over a period of six months. These results exhibit time- and breed-specific expression patterns of GLUT2 and GLUT4, which highlight their potential as candidate genes for assessing adipose deposition and muscle development in pigs. These differences in the expression of GLUT family genes may also have indications for meat quality.

Downregulation of miR-302c and miR-520c by 1,25(OH)2D3 treatment enhances the susceptibility of tumour cells to natural killer cell-mediated cytotoxicity.

BACKGROUND: NKG2D recognises several ligands, including polymorphic major histocompatibility complex class I chain-related chain-related proteins A and B (MICA/B) and unique long 16-binding proteins (ULBPs). These ligands are present on cancer cells and are recognised by NKG2D in a cell-structure-sensing manner, triggering natural killer (NK) cell cytotoxicity. However, the mechanisms that control the expression of NKG2D ligands in malignant cells are poorly understood. 1-α,25-Dihydroxyvitamin D3 (1,25(OH)2D3) was recently shown to enhance the susceptibility of melanoma cells to the cytotoxicity of NK cells. However, the function of 1,25(OH)2D3 in other cancers and its potential mechanisms of action remain unknown. METHODS: The expression levels of miR-302c and miR-520c in Kasumi-1, K562, MCF7 and MDA-MB-231 cells were evaluated using quantitative real-time PCR. The targets of miR-302c and miR-520c were confirmed by luciferase reporter assay. The killing effects of NK92 cells against Kasumi-1, K562, MCF7 and MDA-MB-231 cells were examined using the CytoTox 96 Non-Radioactive Cytotoxicity Assay. The levels of cytokines IFN-γ and granzyme B, which indicate the activation of NK cells, were also measured by enzyme-linked immunosorbent assay. RESULTS: Treatment with 1,25(OH)2D3 enhanced the susceptibility of both the haematological tumour cell line Kasumi-1 and solid tumour cell line MDA-MB-231 to NK92 cells. miR-302c and miR-520c expression was induced, and their levels inversely correlated with the levels of NKG2D ligands MICA/B and ULBP2 upon 1,25(OH)2D3 treatment. A luciferase reporter assay revealed that miR-302c and miR-520c directly targeted the 3'-UTRs of MICA/B and ULBP2 and negatively regulated the expression of MIA/B and ULBP2. Moreover, upregulation of miR-302c or miR-520c by transfection of their mimics remarkably reduced the viability of Kasumi-1 cells upon NK cell co-incubation. By contrast, the suppression of the activity of miR-302c or miR-520c by their respective antisense oligonucleotides improved the resistance of Kasumi-1 cells to NK cells. CONCLUSION: 1,25(OH)2D3 facilitates the immuno-attack of NK cells against malignant cells partly through downregulation of miR-302c and miR-520c and hence upregulation of the NKG2D ligands MICA/B and ULBP2.

Serum secretory phospholipase A2-IIa (sPLA2-IIA) levels in patients surviving acute myocardial infarction.

BACKGROUND: The increase of secretory phospholipase A2-IIa (sPLA2-IIa) in culprit coronary lesions is associated with myocardial infarction, and the increase of sPLA2-IIa in peripheral plasma levels has a significant risk and prognostic value in patients with coronary artery disease. Little is known about the prognostic significance of elevated serum sPLA2-IIa in post-acute myocardial infarction (post-AMI) patients. OBJECTIVES: The present study is designed to investigate the potential association between serum sPLA2-IIa and prognosis in post-acute myocardial infarction (post-AMI) patients. PATIENTS AND METHODS: From Oct 1998 to Sep 2008, a total of 964 post-AMI patients with serum samples collected in the convalescent stage were studied. Serum levels of sPLA2-IIa were measured by ELISA. According to the optimal cut-off value for sPLA2-IIa concentration, patients were then divided into 2 groups. Categorical variables were compared between the 2 groups using the χ2 test. All continuous variables are described as mean ± SD and were compared using Student's t-test. Statistical associations between clinicopathological observations and sPLA2-IIa levels were determined using the Mann-Whitney U test. The clinical value of sPLA2-IIa level as a prognostic parameter was evaluated using the Cox's proportional hazards model. RESULTS: During a median follow-up period of 1,462 days, 123 patients (12.7%) had adverse events (all-cause mortality, n=52; non-fatal MI, n=31; readmission for heart failure [HF], n=40). Patients were divided into 2 groups according to a serum sPLA2-IIa level of 360 ng/dl, which was determined to be the optimal cut-off for discriminating all-cause mortality based on the maximum value of the area under the receiver operating characteristic curve. Patients with elevated sPLA2-IIa (> 360 ng/dl, n=164) had a significantly higher prevalence of death (18.3% [30/164] vs. 2.75% [22/800] p < 0.001) and readmission for HF (14% [23/164/ vs. 2.1% [17/800], p < 0.0001), but not of non-fatal MI (4.88% [8/164]vs. 2.87% [23/800], p = 0.096), compared to those with sPLA2-IIa < 360 ng/dl. Multivariate Cox regression analysis indicated that elevated serum sPLA2-IIa was associated with an increased risk of mortality and readmission for HF. CONCLUSIONS: Elevated serum sPLA2-IIa during the convalescent stage of AMI predicted long-term mortality and readmission for HF after survival discharge in the post-AMI patients.

Suitable internal control microRNA genes for measuring miRNA abundance in pig milk during different lactation periods.

Determination of an optimal set/number of internal control microRNA (miRNA) genes is a critical, but often undervalued, detail of quantitative gene expression analysis. No validated internal genes for miRNA quantitative PCR (q-PCR) in pig milk were available. We compared the expression stability of six porcine internal control miRNA genes in pig milk from different lactation periods (1 h, 3 days, 7 days, 14 days, 21 days, and 28 days postpartum), using an EvaGreen q-PCR approach. We found that using the three most stable internal control genes to calculate the normalization factor is sufficient for producing reliable q-PCR expression data. We also found that miRNAs are superior to ribosomal RNA (rRNA) and snRNA, which are commonly used as internal controls for normalizing miRNA q-PCR data. In terms of economic and experimental feasibility, we recommend the use of the three most stable internal control miRNA genes (miR-17, -107 and -103) for calculating the normalization factors for pig milk samples from different lactation periods. These results can be applied to future studies aimed at measuring miRNA abundance in porcine milk.