Exosomes derived from stem cells from apical papilla promote angiogenesis via miR-126 under hypoxia.

OBJECTIVES: To explore the effect of exosomal miR-126 derived from stem cells from the apical papilla (SCAPs) under hypoxia on human umbilical vein endothelial cell (HUVEC) angiogenesis. METHODS: miR-126 mimics plasmids were used to upregulate miR-126 in SCAPs. Internalization of PKH26-labeled exosomes was examined by fluorescent microscopy. CCK-8 assay, Transwell assay, scratch assay, tube formation assay, and Matrigel plug assay were performed to detect the effects of exosomes on the angiogenic ability of HUVECs. The luciferase reporter assay and rescue assay were performed to examine the relationship between miR-126 and sprouty-related, EVH1 domain-containing protein 1 (SPRED1). The involvement of SPRED1 and the extracellular signal-regulated kinase (ERK) signaling pathway was evaluated by western blotting. RESULTS: miR-126 expression was upregulated in SCAPs and in SCAP-derived exosomes under hypoxia. miR-126 expression was increased in HUVECs when cocultured with SCAP-derived exosomes. Induced overexpression of miR-126 in hypoxic SCAPs and secreted exosomes resulted in enhanced angiogenesis both in vitro and in vivo. Western blot analysis revealed that miR-126-mediated SPRED1 downregulation induced activation of ERK signaling. CONCLUSIONS: Under hypoxic conditions, exosomes derived from SCAPs can promote HUVEC angiogenesis through expression of miR-126, which subsequently suppresses SPRED1 and activates the ERK signaling pathway.

microRNA-126 inhibits vascular cell adhesion molecule-1 and interleukin-1beta in human dental pulp cells.

BACKGROUND: Vascular cell adhesion molecule (VCAM-1) mediates pulpitis via regulating interleukin (IL)-1ß. microRNA (miR)-126 was reported to regulate the VCAM-1 under many different pathophysiological circumstances. We investigated variations of miR-126 and VCAM-1 in inflamed patient pulp tissues and determined potential roles of miR-126 in pulpitis using human dental pulp cells (hDPCs) in vitro. METHODS: We quantitatively measured the transcripts of miR-126 and VCAM-1 in inflamed human pulp tissues using qRT-PCR and compared with those from healthy human pulp tissues. In addition, we transfected miR-126 in hDPCs using plasmid DNA (pDNA)-encoding miR-126 delivered by polyethylenimine (PEI) nanoparticles. RESULTS: The irreversible pulpitis significantly reduced miR-126 and increased the transcript of VCAM-1 in pulp tissues (p < 0.05). pDNA-encoding miR-126 delivered PEI nanoparticles and effectively upregulated the expression of miR-126 in hDPCs (p < 0.05). The overexpression of miR-126 could effectively suppress the transcripts and protein levels of VCAM-1 and IL-1ß induced by Pg-LPS at 100ng/mL in DPCs (p < 0.05). CONCLUSIONS: miR-126 is involved in pulpitis and downregulated the VCAM-1 and IL-1ß in DPCs. miR-126 may be a potential target to attenuate the inflammation of pulpitis.

[Differential expression of pro-angiogenic miRNAs in dental tissue-derived stem cells under hypoxia].

PURPOSE: To explore pro-angiogenic miRNAs differentially expressed in dental tissue-derived stem cells under hypoxia. METHODS: Stem cells from apical papilla, dental pulp stem cells and periodontal ligament stem cells were obtained from 3 patients, and treated with nomoxia or hypoxia for 1, 3, 5 d, respectively. Real-time PCR was performed to evaluate the expression of 9 specifically identified pro-angiogenic miRNAs and HIF-1α. SPSS 19.0 software package was used for statistical analysis. RESULTS: At the fifth day of hypoxic condition, as for SCAPs, the expression of miR-126 was relatively increased while miR-20a, miR-20b, miR-21, miR-130a, miR-132, miR-210 and miR-503 deceased. As for DPSCs, the expression of miR-21, miR-130a, miR-126 and miR-210 were relatively increased while miR-132 decreased. As for PDLSCs, the expression of miR-126, miR-21 and miR-296 were relatively increased. Finally, the expression of HIF-1α was relatively upregulated in all three type of cells. CONCLUSIONS: Pro-angiogenic miRNAs in dental tissue-derived stem cells under hypoxia exists specific expression profile.

Proteome analysis of maize seeds: the effect of artificial ageing.

Previous understanding of the mechanism of seed ageing is largely based on observations on imbibed seeds rather than dry seeds. The present research was conducted to investigate whether seed ageing has effects on the dry seeds through proteome analysis. Maize (Zea mays cv. Dabaitou) seeds were artificially aged at 50°C (13.58% moisture content) for 5 or 13 days, and the total protein was extracted from embryos of the dry seeds. Two-dimensional electrophoresis was performed and the differentially expressed proteins were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. A total of 40 proteins were identified, in which 16 proteins were upregulated, indicating that artificial ageing affected the proteome of the dry seeds. Proteomic studies revealed that the signal transduction and transcription were disturbed by artificial ageing, which might lead to reduced protection against ageing. Artificial ageing also increased proteases and broke down stored proteins, impaired metabolism and energy supply, and ultimately resulted in seed deterioration. Proteins involved in metabolism and energy were the largest downregulated protein group, with regard to glycolysis, tricarboxylic acid cycle, the electron transport chain and oxidative phosphorylation. The downregulation of these proteins, together with reduction in the specific activity of glucose-6-phosphate dehydrogenase, and the content of glucose 6-phosphate, pyruvic acid and ATP in aged seeds, suggested the important roles of the mobilization of stored carbohydrates and energy supply in seed ageing and seed vigor. The present work provides new information about the proteomic changes during seed ageing and provides a possible mechanism for seed deterioration.