Characterization and intracellular delivery of MK2-inhibitor peptides for inflammatory applications

The inflammatory response is essential for the body\u27s recovery from injury and infection; however, chronic inflammation can lead to tissue destruction. Several different diseases result from chronic inflammation, including rheumatoid arthritis, which is characterized by decreased mobility due to joint erosion and the upregulation of inflammatory cytokines. Although several therapies are available to treat inflammatory diseases, each therapy has disadvantages that limit its use in a portion of the population, including cost, efficacy, and adverse effects. An ideal therapeutic should utilize knowledge of the disease pathology, while showing efficacy and reducing adverse side effects. Our lab has developed a family of peptide inhibitors capable of inhibiting mitogen activated protein kinase activated protein kinase 2 (MAPKAP K2 or MK2) in vitro. MK2 appears to be a promising target for inflammation because it plays a role in regulating several cytokines that perpetuate inflammation. The overall goal of my research is to determine if these peptide inhibitors are applicable as a therapy for inflammation and characterize their mechanism of delivery, thus ensuring that these therapeutics will succeed where other inflammatory therapies have not. Our peptide therapeutics are designed with two different domains: (1) a functional domain that inhibits the kinase MK2 and (2) a cell-penetrating peptide (CPP) domain, which delivers the therapy into the cell. In this dissertation, I address our findings regarding the specificity, toxicity, and efficacy of these peptide inhibitors. We find that choice of cell-penetrating peptide domain dramatically influences the properties of the therapy. In addition, we have characterized the mechanism of intracellular uptake of the MK2 inhibitors in two different cell lines. In investigating the role that substrate stiffness plays in uptake and efficacy, we have improved our in vitro cell culture models to better replicate what is observed in vivo. These results advance our current understanding of the mechanism of action of the MK2-inhibitor peptides and suggest that these peptide inhibitors have the potential to be an effective therapy for inflammatory diseases