Optimization of Inhibitory Peptide Delivery to Block GPCR Induced Inflammation

Abstract

A key mediator of angiogenesis and inflammatory response in chronic lung disease is the mitogen‐activated kinase (MAP), p38α. The typical activation pathway for p38α uses MAP kinase kinase 3 (MKK3), and MKK6 to phosphorylate and activate p38α. However, an atypical p38α signaling pathway was discovered in a family of pro‐inflammatory G‐protein coupled receptors (GPCRs). The atypical pathway uses transforming growth factor β activated kinase 1 binding protein‐1 (TAB1) as opposed to MKK3/6 to interact with p38α. The binding of TAB1 to p38α induces the autophosphorylation of p38α which leads to increased proangiogenic signaling. Recent studies have highlighted the use of cell‐penetrating inhibitors that specifically block atypical p38 signaling, leaving MKK3/6 dependent signaling intact to maintain normal cellular function. We have shown that we can label peptide inhibitors with a red fluorescent protein which can be transiently expressed in endothelial cells. Using a lentivirus we are generating endothelial cell lines stably expressing an array of RFP linked inhibitor peptides targeted for exosomal packaging. Purified peptide loaded exosomes/nanocarriers are then used to deliver inhibitors to vascular cells in vitro. Our current studies focus on assessing the cellular uptake of peptide loaded exosomes by observing the mRFP using confocal microscopy and immunoblotting. We predict that exosomally delivered peptides inhibit p38 signaling by GPCR ligands in endothelial cells. These studies will demonstrate the potential for exosomal nanocarriers to deliver peptide inhibitors to block GPCR inflammation.