Highly specific real-time quantification of diverse microRNAs in human samples using universal primer set frame

Simultaneous detection and imaging of two specific miRNAs using DNA tetrahedron-based catalytic hairpin assembly

Improving the accuracy, sensitivity and speed of intracellular miRNA imaging is essential for early diagnosis of cancer. To achieve this goal, we herein present a strategy for imaging two distinct miRNAs by DNA tetrahedron-based catalytic hairpin assembly (DCHA). Two nanoprobes, DTH-13 and DTH-24, were prepared by one-pot synthesis. The resultant structures were DNA tetrahedrons functionalized with two sets of CHA hairpins, which respectively responded to miR-21 and miR-155. Using these structured DNA nanoparticles as the carriers, the probes could easily enter living cells. The presence of miR-21 or miR-155 could trigger CHA between DTH-13 and DTH-24, leading to independent fluorescence signals of FAM and Cy3. In this system, the sensitivity and kinetics were significantly enhanced owing to the strategy of DCHA. The sensing performance of our method was thoroughly investigated in buffers, fetal bovine serum (FBS) solutions, living cells, and clinical tissue samples. The results validated the potential of DTH nanoprobes as a diagnostic tool for early stages of cancer.

qPCR-based methods for expression analysis of miRNAs

Several approaches for miRNA expression analysis have been developed in recent years. In this article, we provide an updated and comprehensive review of available qPCR-based methods for miRNA expression analysis and discuss their advantages and disadvantages. Existing techniques involve the use of stem-loop reverse transcriptase-PCR, polyadenylation of RNAs, ligation of adapters or RT with complex primers, using universal or miRNA-specific qPCR primers and/or probes. Many of these methods are oriented towards the expression analysis of mature miRNAs and few are designed for the study of pre-miRNAs and pri-miRNAs. We also discuss findings from articles that compare results from existing methods. Finally, we suggest key points for the improvement of available techniques and for the future development of additional methods.

Biomarkers in Islet Cell Transplantation for Type 1 Diabetes

PURPOSE OF REVIEW

Islet transplantation, an important approach to achieve insulin independence for individuals with type 1 diabetes, is limited by the lack of accurate biomarkers to track beta-cell death post islet infusion. In this review, we will discuss existing and recently described biomarkers.

RECENT FINDINGS

As beta cells are killed by the immune system, fragments of beta cell-specific cell-free DNA and proteins are released into the periphery. Several different strategies to identify these fragments have been described. Some circulating, non-coding microRNAs, particularly miRNA-375 are also showing potential to reflect the rate of beta cell loss post-clinical islet transplantation. Recent advances in identifying accurate beta cell-specific biomarkers such as differentially methylated insulin cell-free DNA and circulating miRNA-375 may help predict clinical outcomes. More studies are required to examine the robustness of these biomarkers to detect chronic beta-cell loss in islet transplantation recipients.