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Aims: The impaired angiogenesis is one of the main factors affecting the healing of diabetic foot ulcer (DFU) wounds. Maggot debridement therapy (MDT) promotes granulation tissue growth and angiogenesis during DFU wound healing. Non-coding microRNAs can also promote local angiogenesis in DFU wounds by regulating wound repairing related gene expression. The purpose of this study was to investigate the mechanism of microRNAs in MDT promoting DFU wound angiogenesis.Methods: In this study, we applied MDT to treat DFU wound tissue and detect the expression of the miR-17-92 cluster. In vitro experiments, human umbilical vein endothelial cells (HUVECs) were treated with maggot excretions/secretions (ES), the miR-17-92 cluster and the predicted target gene expression were measured. Tube formation assay and cell scratch assay were performed when inhibition of miR-18a/19a or overexpression of thrombospondin-1 (TSP-1) were used in this study.Results: miR-18a/19a transcription significantly up-regulated and TSP-1 expression down-regulated in patients wound tissue and in HUVECs. Inhibition of miR-18a/19a or overexpression of TSP-1 partially blocked the migration and tube formation ability stimulated by ES.Conclusion: Targeted activation of miR-18a/19a transcription levels and subsequent regulation of TSP-1 expression may be a novel therapeutic strategy for DFU. [ABSTRACT FROM AUTHOR]

Abstract: MicroRNAs (miRNA) participate in regulating diverse biological pathways by translational repression in animals. They have attracted increasing attention recently. However, little work has been done on the miRNA genes in agriculturally important pests. Because the transcripts of most miRNA genes are the products of type-II RNA polymerase, pri-miRNA has a poly(A) tail and appears in expressed sequence tags (EST). We developed a computational pipeline to identify miRNA genes from insect ESTs. First, 980,697 ESTs from 63 insects were collected and used to search the nr database. The ESTs which did not share significant similarities with any known protein-coding genes were treated as non-coding ESTs. Next, known mature miRNAs were used to align with non-coding ESTs. The ESTs which contain the sequence of mature miRNA were treated as candidate ESTs. Finally, putative precursors were extracted flanking the mature miRNA region in candidate ESTs and evaluated by the Triplet-SVM algorithm. As a result, 86 miRNAs from 30 insect species were found based on a strict criterion while 330 miRNAs from 51 species were found based on a loose criterion. Evolution analysis indicated that mir-467, mir-297 and mir-466 were the highest conserved miRNA families in insects. To confirm the reliability of putative insect miRNAs, the expression profile of nine predicted miRNAs in Locusta migratoria was investigated. Eight miRNAs were successfully detected by RT-PCR. Most miRNAs were expressed ubiquitously at all examined tissues and developmental stages whereas Lmi-mir-509 was specifically expressed in the thorax of the 2nd, 4th and 5th instars and adult locust. In all, our work reported an efficient computational strategy for predicting miRNA genes from insect ESTs and presented tens of miRNAs in diverse insect species which are expected to participate in many important physiological processes. [ABSTRACT FROM AUTHOR]