The ability to design nanostructures with arbitrary shapes and controllable motions has made DNA nanomaterials used widely to construct diverse nanomachines with various structures and functions. The DNA nanostructures exhibit excellent properties, including programmability, stability, biocompatibility, and can be modified with different functional groups. Among these nanoscale architectures, DNA walker is one of the most popular nanodevices with ingenious design and flexible function. In the past several years, DNA walkers have made amazing progress ranging from structural design to biological applications including constructing biosensors for the detection of cancer‐associated biomarkers. In this review, the key driving forces of DNA walkers are first summarized. Then, the DNA walkers with different numbers of legs are introduced. Furthermore, the biosensing applications of DNA walkers including the detection‐ of nucleic acids, proteins, ions, and bacteria are summarized. Finally, the new frontiers and opportunities for developing DNA walker‐based biosensors are discussed.

BACKGROUND: Endothelial cell (EC) dysfunction and vascular inflammation are critical in the initiation and progression of atherosclerosis. Long noncoding RNAs play a critical role in vascular pathology, but relatively little is known about their involvement in controlling vascular inflammation. MIR181A1HG is a conserved long noncoding RNA located in juxtaposition with miR-181a1 and miR-181b1, both involved in vascular inflammation. The study aims to investigate the role of MIR181A1HG in regulating vascular inflammation. METHODS: We examined the expression of MIR181A1HG in both human and mouse atherosclerotic lesions. Loss-of-function and gain-of-function studies, and multiple RNA-protein interaction assays were used to investigate the role and molecular mechanisms of MIR181A1HG in vascular inflammation and atherosclerosis. The atherosclerotic phenotypes of MIR181A1HG ^−/− ApoE ^−/− mice were analyzed in combination with single-cell RNA sequencing. The transcriptional regulation of MIR181A1HG was verified through luciferase reporter and chromatin immunoprecipitation assays. RESULTS: MIR181A1HG expression was abundant in ECs and significantly increased in both human and mouse atherosclerotic lesions. MIR181A1HG ^−/− ApoE ^−/− mice had reduced NLRP (NLR family pyrin domain containing) 3 inflammasome signaling, EC activation, monocyte infiltration, and atherosclerotic lesion formation. Genetic deletion of MIR181A1HG in myeloid sells did not alter the progression of atherosclerosis. Single-cell RNA sequencing analysis revealed that MIR181A1HG deficiency reduced the proportion of immune cells and enriched anti-inflammation pathways in EC clusters in atherosclerotic lesions. In contrast, EC-specific MIR181A1HG overexpression promoted NLRP3 inflammasome signaling, EC activation, and atherosclerotic lesion formation, effects that were reversed by pharmacological inhibition of NLRP3 (MCC950). MIR181A1HG was transcriptionally activated via an NF-κB (nuclear factor kappa B)/p65-dependent pathway. Mechanistically, MIR181A1HG mediated these effects on regulating NLRP3 inflammasome and EC activation in part through decoying Foxp1 (forkhead box transcription factor 1) away from the promoters of target genes, which was independent of the miR-181a1/b1 cluster. Finally, EC-specific Foxp1 silencing reversed the antiatherosclerotic effect mediated by MIR181A1HG-deletion in vivo. CONCLUSIONS: These findings identify MIR181A1HG as a central driver of vascular inflammation in atherosclerosis by its ability to decoy Foxp1 away from target gene promoters and activate NLRP3 inflammasome in the vascular endothelium. Our study suggests MIR181A1HG as a future therapeutic target for vascular inflammatory disease states.

Growing evidence has well established the protective effects of CYP2J2/EET on the cardiovascular system. The aim of the present study was to determine whether CYP2J2/EET has a preventive effect on atrial fibrillation (AF) and to investigate the underlying mechanisms. Wild‐type mice were injected with or without AAV9‐CYP2J2 before abdominal aortic constriction (AAC) operation. After 8 weeks, compared with wild‐type mice, AAC mice display higher AF inducibility and longer AF durations, which were remarkably attenuated with AAV9‐CYP2J2. Also, AAV9‐CYP2J2 reduced atrial fibrosis area and the deposit of collagen‐I/III in AAC mice, accompanied by the blockade of TGF‐β/Smad‐2/3 signalling pathways, as well as the recovery in Smad‐7 expression. In vitro, isolated atrial fibroblasts were administrated with TGF‐β1, EET, EEZE, GW9662, SiRNA Smad‐7 and pre‐MiR‐21, and EET was demonstrated to restrain the differentiation of atrial fibroblasts largely dependent on Smad‐7, due to the inhibition of EET on MiR‐21. In addition, increased inflammatory cytokines, as well as activated NF‐κB pathways induced by AAC surgery, were also significantly blunted by AAV9‐CYP2J2 treatment. These effects of CYP2J2/EET were partially blocked by GW9662, the antagonist of PPAR‐γ. In conclusion, this study revealed that CYP2J2/EET ameliorates atrial fibrosis through modulating atrial fibroblasts activation by disinhibition of MiR‐21 on Smad‐7, and attenuates atrial inflammatory response by repressing NF‐κB pathways, reducing the vulnerability to AF, and CYP2J2/EET exerts its role at least partially through PPAR‐γ activation. Our findings might provide a novel upstream therapeutic strategy for AF.

Postischemic myocardial fibrosis is a factor for the development of cardiac dysfunction and malignant cardiac arrhythmias, and no effective therapy is currently available. Circular RNAs are emerging as important epigenetic players in various biological functions; however, their roles in cardiac fibrosis are unknown. With the use of a rat model of postischemic myocardial fibrosis, we identified an increase in circHNRNPH1 in the ischemic myocardium after myocardial infarction, particularly in cardiac fibroblasts. In cardiac fibroblasts, circHNRNPH1 was responsive to transforming growth factor β1 (TGF-β1), the principal profibrotic factor. The downregulation of circHNRNPH1, in contrast to its overexpression, promoted myofibroblast migration and α-smooth muscle actin and collagen I expression and inhibited myofibroblast apoptosis. The recombinant adeno-associated virus 9 (rAAV9)-mediated, cardiac-specific knockdown of circHNNRPH1 accordingly facilitated cardiac fibrosis and aggravated cardiac dysfunction. Mechanistically, circHNRNPH1 colocalized with and sponged microRNA (miR)-216-5p in the cytoplasm of cardiac fibroblasts to induce SMAD7 (protein family of signal transduction component of the canonical transforming growth factor-β signaling pathway) expression, accelerating the degradation of TGF-β receptor I. Thus, our results indicated that circHNRNPH1 negatively regulates the fibrogenesis of cardiac fibroblasts and may provide a new therapeutic strategy for postischemic myocardial fibrosis.