Circ_LAS1L regulates cardiac fibroblast activation, growth, and migration through miR-125b/SFRP5 pathway.

Current studies have shown that circular RNAs (circRNAs) and microRNAs (miRNAs) are closely related in acute myocardial infarction (AMI). Previous studies have shown that miR-125b promotes fibrosis and up-regulates in cardiac fibroblasts (CFs), and further experiments showed that circ_LAS1L had multiple binding sites of miR-125b, and their expression was inversely related in AMI patients and CFs. RNA immunoprecipitation (RIP), pull down, and dual luciferase reporter gene assay all confirmed that miR-125b directly bound to circ_LAS1L. Circ_LAS1L overexpression promoted the expression of downstream target gene secreted frizzled-related protein 5 (SFRP5), inhibited the expression of alpha-SMA, collagen I, and collagen III, inhibited CF proliferation and migration, and promoted apoptosis. When cotransfected with circ_LAS1L overexpression vector and miR-125b mimics, the above gene expression and CF biological behaviours did not change significantly. But when cotransfected with circ_LAS1L overexpression vector and SFRP5 siRNA, SFRP5 expression was still down-regulated, the expression of alpha-SMA, collagen I, and collagen III was up-regulated, and the proliferation and migration of CFs were increased. Therefore, circ_LAS1L inhibits the activity of miR-125b by adsorbing it, thus promoting the expression of SFRP5 and then regulating the biological characteristics of CFs. These findings may provide an important experimental basis for the regulation of myocardial fibrosis after myocardial infarction. SIGNIFICANCE OF THE STUDY: Studies have shown that circular RNAs (circRNAs) play important roles in cardiovascular diseases, but there are few studies on their roles in the process of myocardial fibrosis. In this study, we found that circ_LAS1L was down-regulated in acute myocardial infarction (AMI) patients and cardiac fibroblasts (CFs), and could bind directly to miR-125b, thereby promoting the expression of downstream target gene secreted frizzled-related protein 5 (SFRP5), ultimately inhibiting the activation, proliferation and migration of CF, and promoting apoptosis. This suggests that circ_LAS1L/miR-125b/SFRP5 pathway can regulate the biological function of CF and may play an important role in the process of myocardial fibrosis, thus providing an important theoretical basis for the regulation of myocardial fibrosis after myocardial infarction.

Multiresidue analysis of 59 nonallowed substances and other contaminants in cosmetics.

A method was developed for the determination of 59 glucocorticoids, sex hormones, nonsteroidal anti-inflammatory drugs, antibiotics, and other contaminants in cosmetics simultaneously by ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Acetonitrile was used to extract the sample, and the mixed sorbents were dispersed for purification. With the optimal conditions, the optimized pretreatment processes led to no significant interference on analysis from an extremely complicated sample matrix, and the linear ranges of 59 analytes were 0-480.0 µg/kg with the correlation coefficients above 0.99 and the limits of quantification (S/N≥10) were 5-40 µg/kg. Statistical evaluation revealed that the average recoveries were in the range of 61.2-131.2%, and relative standard deviations were in the range of 2.0-22.8%, meanwhile the interday precision ranged from 3.8 to 21.8%. This method is simple, fast, and credible, and it can be applied to simultaneous screening and determination of various classes of substances under investigations illegally presented in cosmetic products, covering a wide diversity of polarities, and pKa values.