A novel strategy for enhancing the stability of aptamer conformations in heavy metal ion detection.

BACKGROUND: Detection methods based on aptamer probes have great potential and progress in the field of rapid detection of heavy metal ions. However, the unstable conformation of aptamers often results in poor sensitivity due to the dissociation of aptamer-target complex in real environments. RESULTS: In this study, we developed a locking aptamer probe and combined it with AgInZnS quantum dots for the first time to detect cadmium ions. When cadmium ions are combined with the probe, the cadmium ions are fixed in the core-locking position, forming a stable cavity structure. The limit of detection (LOD) was achieved at a concentration of 6.9 nmol L-1, with a broad detection range from 10 nmol L-1 to 1000 µmol L-1, and good recovery rates (92.93%-102.8 %) were achieved in aquatic product testing. The locking aptamer probe with stable conformation effectively enhances the stability of the aptamer-target complex and remains good stability in four buffer environments as well as a 600 mmol L-1 salt solution; it also exhibits good stability at pH 6.5-7.5 and temperatures ranging from 25 °C to 35 °C. SIGNIFICANCE: Overall, our study presented a general, simple, and cost-effective strategy for stabilizing aptamer conformations, and used for highly sensitive detection of cadmium ions.

Hsa_circ_0007334 Promotes the Osteogenic Differentiation and Proliferation of Human Bone Marrow Mesenchymal Stem Cells by Sponging miR-144-3p.

This study aimed to identify the possible function and the molecular mechanism of hsa_circ_0007334 in human bone marrow mesenchymal stem cells (hBMSCs) osteogenic differentiation. The level of hsa_circ_0007334 was detected by means of quantitative real-time polymerase chain reaction (RT-qPCR). Alkaline phosphatase (ALP), RUNX2, osterix (OSX), and osteocalcin (OCN) were monitored to analyze the degree of osteogenic differentiation under routine culture or under the control of hsa_circ_0007334. The proliferation of hBMSCs was tested with a cell counting kit-8 (CCK-8) assay. The migration of hBMSCs was tested using the Transwell assay. Bioinformatics analysis was used to predict the possible targets of hsa_circ_0007334 or miR-144-3p. Dual-luciferase reporter assay system was used to analyze the combination between hsa_circ_0007334 and miR-144-3p. Hsa_circ_0007334 was upregulated in osteogenic differentiation of hBMSCs. Osteogenic differentiation increased by hsa_circ_0007334 in vitro was confirmed with levels of ALP and bone markers (RUNX2, OCN, OSX). hsa_circ_0007334 overexpression promoted osteogenic differentiation, proliferation, and migration of hBMSCs, and knockdown of hsa_circ_0007334 has the opposite effects. miR-144-3p was identified as the target of hsa_circ_0007334. The targeting genes of miR-144-3p are involved in osteogenic-differentia-tion-related biological processes (such as bone development, epithelial cell proliferation, and mesenchymal cell apoptotic prosess) and pathways (including FoxO and VEGF signaling pathway). Hsa_circ_0007334, therefore, presents itself as a promising biological for osteogenic differentiation.

Overexpression of CAP1 and its significance in tumor cell proliferation, migration and invasion in glioma.

Adenylate cyclase-associated protein 1 (CAP1), a protein related to the regulation of actin filaments and the Ras/cAMP pathway, is associated with tumor progression. Nevertheless, the expression level and effects of CAP1 in regards to glioma have not been reported. In the present study, we examined the expression of CAP1 in glioma and tumor adjacent normal brain tissues by tissue microarray and immunohistochemistry. Our results showed that CAP1 was overexpressed in glioma tissues in comparison with that noted in the tumor adjacent normal brain tissues and increased staining of CAP1 was found to be correlated with WHO stage. In addition, we discovered that knockdown of CAP1 by specific RNA interference markedly inhibited cell growth and caused downregulation of the proliferation markers, PCNA and cyclin A. We further demonstrated that knockdown of CAP1 inhibited cell metastatic abilities by downregulating N-cadherin and vimentin and upregulating E-cadherin. These findings revealed that CAP1 expression is markedly increased in human glioma and that downregulation of CAP1 in tumors may serve as a treatment for glioma patients.