The objective of this project is to use a genomics approach to identify and demonstrate that specific microRNA molecules impede wound healing in diabetic individuals, thus indicating their potential as novel therapeutic targets. This projet responds to RFA-NR-12-002 by addressing following areas of research interest: a) Elucidation of the genomic markers/mechanisms related to chronic wound susceptibility, development, progression, and repair~ b) Development and testing of genomic based interventions aimed at preventing chronic wounds and/or expediting the healing process. Diabetic foot ulcers (DFUs) are one of the major complications of diabetes mellitus leadin to lower extremity amputation for thousands of diabetic persons each year. Thus, there is a critical unmet need for specific and effective therapeutics to improve healing of these chronic wounds. miRNAs constitute non-coding genomic species that regulate gene expression through post-transcriptional gene silencing and can be neutralized with synthetic small-molecule drugs. Preliminary studies in our laboratory identified a set of miRNAs that are selectively over-expressed in chronic wounds, inhibit acute wound healing in vivo, and may represent potential therapeutic targets. The goals of this project are to test the hypothesis that induction of DFU-specific miRNAs causes healing impairment by repressing genes that coordinate wound healing process, and to determine if targeting them with antagomirs (sequence-specific anti-miRNA oligonucleotides) reverses the healing impairment.
Aim 1 is to characterize inhibition of healing in vitro and in vivo by miRNAs identified as induced in DFU patients by quantifying miRNAs in tissue biopsies from DFUs, and using the DFU-induced miRNAs to reconstruct the chronic DFU in acute experimental wounds in mice.
Aim 2 is to define the functional role of DFU-specific miRNAs by using synthetic antagomirs to target DFU-specific miRNAs and reverse the non-healing phenotype in primary cell cultures generated from patients'DFU biopsies and in the mouse wound healing model in vivo.
Aim 3 is to identify DFU-specific miRNAs and determine their downstream targets specific for wound healing process by genomics approach of quantifying simultaneously mRNA and miRNA gene expression profiles of DFU biopsies. New miRNAs that are identified by this approach will be validated by the methods of Aims 1 and 2. These studies are novel and significant in applying established miRNA strategies and bioinformatics analysis to the problem of validating potential new therapeutic targets for chronic DFUs. Successful completion of this project will lead to future studies to develop candidate therapeutics through preclinical and clinical testing.
This project applies recent breakthroughs in the genomics science of micro RNA (miRNA) to test if targeting specific miRNA molecules by their synthetic mimics and/or antagomirs in actual patients'wound cells in vitro and mouse wound model in vivo may reverse non-healing characteristics. Successful completion of this project will result in identification of a new class of therapeutic candidates, miRNA molecules, that are responsible for the healing inhibition in chronic diabetic foot ulcers .
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