A novel sshRNA-antimiR combination therapy for accelerating healing of diabetic foot ulcers

Abstract ! The objective of this project is to advance the development of a novel approach to healing chronic diabetic foot ulcersDFUswhich are a major and growing health concern for which existing treatments are often ineffectiveNormal wound healing involves a coordinated cascade of events that are stimulated in part by the hypoxia that results from injury to the vasculature at the wound siteThese events include angiogenesismacrophage recruitmentinhibition of apoptosisand the expansion and mobilization of fibroblasts and keratinocytes for re epithelializationIn chronic woundsthe normal response to hypoxia is impairedand many of these cellular processes are hinderedOur approach involves the therapeutic modulation of a protein and a microRNAmiRNAthat are involved in these hypoxia induced pathways by the use of oligonucleotides acting by two different mechanismsRNA interferenceRNAiand antisenseRNAi is achieved by use of SomaGenicsproprietary sshRNAsynthetic short hairpin RNAdesignwhich eliminates sense strand offtarget effects and has been shown to be highly effective in treating chimeric mice infected with hepatitis C virusIn previous SBIR supported workwe identified oligonucleotides that potently inhibit the protein and miRNA targets in vitro and demonstrated that when these RNAs are incorporated into a medicated bandage by a layer by layerLbLprocess and applied to full thickness wounds of diabetic micehealing is significantly accelerated and regrowth of vasculature is enhancedTreatment was also shown to increase levels of downstream factors promoting angiogenesis and to increase the mobility of keratinocytesThe lack of a perfect animal model for DFU healing has led to a consensus among researchers that efficacy and safety should be demonstrated in two diabetic animal models before moving to human trialsThereforein this new Phase I proposalwe will validate our mouse results in the neuroischemic diabetic rabbit ear model in collaboration with DrAristidis VevesBeth Israel Deaconess Medical Center and Harvard Medical Schoola leading expert in the rabbit ear model and authority on DFU healing in generalWe will continue to employ the bio erodible LbL drug delivery platform that we have adopted in collaboration with DrPaula HammondMITwho has developed this platformIf this Phase I is successful as we expectin Phase II we plan to perform extensive lead optimization and refinement of our LbL delivery methodincluding further development of chemical modification patterns that stabilize the RNAs against ribonucleases present in the wound bed without compromising potency or introducing undesired immunostimulatory activityOptimization will also include defining optimal proportions of the two oligonucleotides in the LbL formulationWe will develop a scalable manufacturing process for large scale production of LbL formulated bandage materialFinallypreliminary but carefully designed safety toxicity studies on a third animal model will be performed!Project Narrative Diabetes is a growing problemwith severe consequences for the health of affected people including amputation of lower extremityand huge cost burdens to the medical systemNew therapeutics that promote rapid wound closure and healing and reduce the risk of infection would be of great benefit to diabetic patients with chronic foot ulcersfor many of whom existing treatments are ineffectiveThe oligonucleotide based therapeutics to be developed in this program will probably not require refrigerationand they are expected to produce relatively long lasting therapeutic effectsallowing for infrequent dosingA product that successfully promotes healing of these wounds could substantially reduce the burden of healthcare costs