Pulmonary surfactant is the complex mixture of lipid and protein that covers the alveolar surface. Pulmonary surfactant deficiency is one of the main causes of neonatal respiratory distress. Recent studies showed that miRNA plays an important role in lung development, but research into miR-431 regulation of pulmonary surfactant are sparse. In this study, we explored the regulatory role of miR-431-5p in the expression of pulmonary surfactant and identified its potential target gene, Smad4. The bioinformatics tool TargetScan was used to predict the targets of miR-431. The expression of miR-431-5p was achieved via transfection of miR-431-5p mimics, an miR-431-5p inhibitor and corresponding negative control. The level of miR-431-5p was determined using quantitative real-time PCR. The CCK8 assay was conducted to confirm cell growth 12 h after transfection with miR-431-5p mimics, inhibitor or NC. Smad4 and surfactant-associated proteins in A549 were analyzed using western blot and quantitative real-time PCR. Smad4 was validated as a target of miR-431 in A549 cells. Overexpression of miR-431 accelerated A549 proliferation and inhibited A549 apoptosis. The mRNA and protein levels for the surfactant proteins (SP-A, SP-B, SP-C and SP-D) were found to be differentially expressed in A549 cells over- or under-expressing miR-431-5p. Our results show that miR-431-5p is critical for pulmonary surfactant expression and that its regulation is closely related to the TGF-β/Smad4 pathway. These results will help us to study the pathophysiological mechanism of lung developmental diseases.

To explore the regulatory networks that underlie the development of chemoresistance in bladder cancer, we analyzed profiles of differentially expressed lncRNAs, circRNAs, miRNAs and mRNAs in gemcitabine-resistant/sensitive bladder cancer cells using next-generation sequencing data. Hundreds of differentially expressed lncRNAs and miRNAs and thousands of circRNAs and mRNAs were identified. Bioinformatics analysis revealed the chromosomal localizations, classification, and coexpression of mRNAs, as well as candidates for cis and trans regulation by lncRNAs. Furthermore, GO and KEGG pathway enrichment analysis of differentially expressed mRNAs and circRNAs indicated important functional roles of co-regulated RNAs, thus establishing ceRNA and protein-protein interactions networks that may underlie chemoresistance in bladder cancer. We demonstrated that lncRNA LINP1 can act as a ceRNA by inhibiting miR-193a-5p to increase TP73 expression; and that lncRNA ESRG and hsa_circ_0075881 can simultaneously bind miR-324-3p to increase ST6GAL1 expression. Modulation of ceRNA network components using ablation and overexpression approaches contributed to gemcitabine resistance in bladder cancer cells. These results elucidate mechanisms by which lncRNAs and circRNAs coregulate the development of bladder cancer cell resistance to gemcitabine, thus laying the foundation for future research to identify biomarkers and disease targets.

Herpes simplex virus (HSV) types 1 + 2 immunoglobulin (Ig)M antibodies assays are important tools for diagnosing pregnant women and their newborns. However, it is unclear whether high levels of rheumatoid factor (RF) interfere with serological methods used to test for HSV types 1 + 2 type-specific IgM antibodies. We report a case of a false-positive result for HSV 1 + 2 IgM antibodies due to gross overestimation of RF by enzyme-linked immunosorbent assay (ELISA). This result occurred in a 25-year-old Han Chinese woman who was 28 weeks pregnant with a fetus (sex of fetus unknown). Antinuclear antibody (ANA) screening was performed, and RF-absorbent material was used. Test results for 3 antibodies of ANA (SSA, Ro-52, and SSB) were positive; the rest of the results were negative. Also, RF levels were significantly higher than normal, as measured by ANA screening. We observed an obvious decrease in HSV 1 + 2 IgM antibodies after removal of RF. Based on our findings, the presence of high concentrations of RF may be responsible for false-positive HSV 1 + 2 ELISA results.