Effects of circular RNA circ-SOD2 on intestinal epithelial barrier and ulcerative colitis / 北京大学学报(医学版)

OBJECTIVE@#To explore the expression profiling of circRNAs in ulcerative colitis(UC) and then determine the significantly changed circRNA and its influences on intestinal epithelial barrier.@*METHODS@#In this study, we selected 5 pairs of inflamed and normal colorectal mucosa tissues from UC patients to perform circRNAs microarray and identified the differentially expressed circRNAs in the UC inflamed colorectal mucosa tissues, and quantitative real-time PCR was used to identify the expression change of circ-SOD2 in 30 UC patients' inflamed and normal colorectal mucosa tissues. We detected the expression of circ-SOD2 in Caco2 and NCM460 cells after being treated with inflammatory factors (LPS, TNF-α, IL1-β). Fluorescence in situ hybridization (FISH) was used to determine the cellular location of circ-SOD2 in the UC colorectal mucosal tissues. The circ-SOD2 overexpression vector was constructed and produced and then transfected into Caco2 cells to examine the cells' trans-epithelial electrical resistance (TEER), permeability of FITC-dextran and the alterations of epithelial barrier related molecules.@*RESULTS@#We found 264 circRNAs (111 increased and 153 decreased) differentially expressed in the inflamed colon mucosa compared with normal colon mucosa using a P-value <0.05 and a >1.5-fold change cutoff. To validate the circRNA microarray results, we selected some circRNAs to perform qRT-PCR based on the following criteria: (1) circRNAs raw data >100 in each sample, (2) fold-change >2, (3) P<0.05. We identified 10 dysregulated circRNA, among them, circ-SOD2 was upregulated with maximum fold-change in the UC inflamed colorectal mucosa tissues. Then we identified circ-SOD2 was upregulated significantly through quantitative real-time PCR (qRT-PCR) in expanded 30 paired colorectal mucosa tissues(P<0.001). After treatments with LPS, TNF-α and IL1-β, circ-SOD2 was upregulated in Caco2 and NCM460 cells at different points from 1 to 7 h. Fluorescence in situ hybridization (FISH) indicated that circ-SOD2 located in intestinal epithelium mostly and few in mesenchyme and inflammatory cells. The overexpression of circ-SOD2 in Caco2 cells resulted in a decrease of transepithelial electrical resistance (TEER), an increase of the FITC-dextran permeability and the downregulation of epithelial barrier related molecule CLDN-8 (P<0.05).@*CONCLUSION@#The dysregulation of circRNAs existed in UC inflamed colorectal mucosa, among which, the upregulated circ-SOD2 weakened the intestinal epithelial barrier and thus might promote the occurrence of ulcerative colitis.

Biological features of exosomes from the plasma and serum preserved for different periods of time / 医学研究生学报

Objective Exosomes play an extremely important role in the diagnosis and treatment of diseases, but very few studies have been reported on the method, time and results of their preservation. We observed the changes in the size, density, morphology and protein expression of exosomes in the plasma and serum preserved for different lengths of time. Methods Using the Exoquick kit, we isolated exosomes in the plasma and serum from healthy humans which were fresh or preserved at a temperature of －80℃ for 1, 3 or 5 years. We analyzed the numbers and diameters of the isolated exosomes with the nanoparticle-tracking analyzer NanoSight NS 300, observed their morphology under the transmission electron microscope, and detected the expressions of the exosome biomarkers TSG101 and CD63 by Western blot. Results The exosomes preserved for different periods of time ranged in diameter from 30 to 200 nm, more observed in the serum than in the plasma, and with no statistically significant difference in the morphological changes among different groups of preservation time. The expressions of the TSG101 and CD63 proteins in the exosomes were decreased with the prolonging of the preservation time, the latter even more significantly than the former. Conclusion There are no statistically significant differences in the diameter or morphology of the exosomes in the human plasma and serum preserved for different periods of time, but the protein biomarkers of the exosomes are decreased significantly with the prolonged time of preservation. Therefore, freshly isolated exosomes are recommended for experiments in the studies of exosome-related proteins.

Correlation between vaspin concentration and insulin sensitivity in the visceral adipose tissue of young obese rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the correlation between visceral adipose tissue-derived serine protease inhibitor (vaspin) concentration and insulin sensitivity in the visceral adipose tissue of young obese Sprague-Dawley (SD) rats.</p><p><b>METHODS</b>Twenty-four SD rats which had been weaned 3 weeks before were randomly divided into two groups (n=12 each) to receive a high-fat and normal diet. The weight and abdominal circumference (AC) of each rat were measured, the fasting plasma glucose (FPG) and fasting insulin (FINS) in blood from the angular vein were measured after 12 hours of fasting and blood glucose (BG) and insulin (INS) levels in blood from the angular vein were measured at 60 and 120 minutes after intraperitoneal injection of 50% glucose (2 g/kg). The rats were sacrificed, and their liver and visceral adipose tissue were weighed. The vaspin concentration of the visceral adipose tissue in each rat was measured using ELISA. Correlation analysis was performed on the vaspin concentration and other indices.</p><p><b>RESULTS</b>Compared with the normal diet group, the high-fat diet group showed significantly higher weight, AC, weight of visceral adipose tissue, FPG, FINS, 120 minute INS level, vaspin concentration, homeostasis model assessment for insulin resistance (HOMA-IR) and homeostasis model assessment of β cell function (HOMA-β) (P<0.05) Insulin sensitivity index (ISI) was significantly lower (P<0.01). Vaspin concentration was positively correlated with visceral adipose tissue and liver weight, AC, 120 minute INS level, FPG, FINS, HOMA-IR and HOMA-β (P<0.05), and negatively correlated with ISI (P<0.05).</p><p><b>CONCLUSIONS</b>High expression of vaspin is associated with insulin resistance in young obese SD rats. Vaspin is presumably an adipocytokine that can increase insulin sensitivity, promote insulin secretion by islet β-cells and improve glucose tolerance, and it may be involved in insulin resistance and the disturbance of carbohydrate metabolism.</p>

Expression of MICA/B protein in esophageal cancer and its clinical significance / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the expression of MICA/B in human esophageal cancer, and to analyze its correlation with clinicopathological features.</p><p><b>METHODS</b>The expression of MICA/B in 40 cases of esophagus carcinoma and corresponding normal esophageal mucosa tissues were examined by immunohistochemistry.</p><p><b>RESULTS</b>The positive rate of expression of MICA/B protein in the esophageal carcinoma was 75.0% (30/40), and that in the corresponding normal esophageal mucosa was 0 (0/40). Up-regulation of MICA/B expression was found in the esophageal carcinomas. The expression of MICA/B was related with histological grade of the esophageal carcinoma (P = 0.012).</p><p><b>CONCLUSION</b>MICA/B protein plays an important role in the esophageal carcinogenesis, and my become a useful molecular marker for the diagnosis of esophageal carcinoma.</p>