U6 miRNA was used as a positive control in normal cornea (Figure 2C). == Figure 2. (antagomirs) using Lipofectamine 2000. Confluent transfected cultures were scratch-wounded with P200 pipette tip. Wound closure was monitored by digital photography. Expression of signaling proteins was detected by immunostaining and Western blot. Using microarrays, 29 miRNAs were identified as differentially expressed in diabetic samples. Two miRNA candidates showing the highest fold increased in expression in the diabetic cornea E.coli polyclonal to V5 Tag.Posi Tag is a 45 kDa recombinant protein expressed in E.coli. It contains five different Tags as shown in the figure. It is bacterial lysate supplied in reducing SDS-PAGE loading buffer. It is intended for use as a positive control in western blot experiments were confirmed by Q-PCR and further characterized. HCEC transfection with h-miR-146a or h-miR-424 significantly retarded wound closure, but their respective antagomirs significantly enhanced wound healing vs. controls. Cells treated with h-miR-146a or h-miR-424 had decreased p-p38 and p-EGFR staining, but these increased over control levels close to the wound edge upon antagomir treatment. In conclusion, several miRNAs with increased expression in human diabetic central corneas were found. Polymyxin B sulphate Two such miRNAs inhibited cultured corneal epithelial cell wound healing. Dysregulation of miRNA expression in human diabetic cornea may be an important mediator of abnormal wound healing. == Introduction == Recently, a family of small noncoding RNAs, microRNAs (miRNAs), have emerged as important regulators in normal and pathological conditions. MicroRNAs play a critical role in the regulation of gene expression at the post-transcriptional level usually resulting in gene silencing via translational repression or target degradation [1-4]. Although a growing number of miRNAs have been identified, relatively little is known about their biological functions and their target mRNAs. Emerging studies indicate that miRNAs are important regulators in a variety of developmental, physiological and pathological processes including cell proliferation, migration, differentiation, apoptosis, inflammation and stem cell maintenance [5-10]. In addition, there is substantial evidence supporting the involvement of miRNAs in many diseases including cancer [11-13], cardiovascular disorders [14,15], and diabetes [16-19], which may have an impact on future treatments of such diseases. The critical role of miRNAs in eye development has been shown using Polymyxin B sulphate conditional Dicer knockout mice, which failed to develop discernible lens and had poorly stratified corneal epithelium [20]. Several retina-specific miRNAs have also been identified in Polymyxin B sulphate human and mouse by microarray analysis and by a 3UTR target finding approach of known retinal genes [7,8]. To date, few studies have addressed the role of these regulators in the eye [6-8,16,17]. Diabetes mellitus (DM) has significant negative effects in the cornea, which can often be sight threatening. Diabetes affects all the layers of the cornea and corneal nerves [21-24]. Corneal abnormalities such as epithelial defects and fragility, recurrent epithelial erosions, decreased sensitivity, abnormal wound repair, increased susceptibility to injury and infection, ulcers, edema, and increased auto-fluorescence have been clinically observed in DM patients with or without diabetic retinopathy (DR) [23,24]. Mechanisms responsible for these changes are still not well understood, which hampers the development of effective treatments, and calls for further studies to understand the causes of corneal diabetic pathology. To date, few studies addressed the expression and function of corneal miRNAs [25-29]. Topographical differences in expression between various ocular surface compartments (central cornea, limbus, and adjacent conjunctiva) were recently described for several corneal miRNAs [30,31]. No data are available yet on miRNA changes in common corneal diseases including diabetic keratopathy. To fill this gap, we performed a global microarray analysis of miRNA expression in normal and diabetic human corneas and successfully identified and confirmed by quantitative real-time RT-PCR (Q-PCR) several miRNAs differentially expressed in diabetic corneas. A wound healing study of two overexpressed miRNAs in a non-transformed human corneal epithelial cell line revealed their role in regulating wound healing that is impaired in the diabetic cornea. == Materials and Methods == == Tissues == Age-matched human autopsy normal, diabetic, and DR corneas and whole eyes were obtained from the National Disease Research Interchange (NDRI, Philadelphia, PA); donor identity was withheld by the supplier. NDRI has a human tissue collection protocol approved by a managerial committee and subject to National Institutes of Health oversight. This work was covered by an exempt IRB protocol EX-1055 from Cedars-Sinai Medical Center. Corneas received in Optisol storage medium (Chiron Vision, Claremont, CA) within 24.
