Poster Presentation ASDR-AWTRS-MEPSA 2018 Joint Meeting

Macrophage activation induces MT1-MMP surface delivery via VAMP7/VAMP8-positive late endosomes and lysosomes in macrophages (#73)

Zoe E West 1 , Annalese BT Semmler 1 , Rachael Z Murray 1
  1. Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia

Chronic wounds are a debilitating condition estimated to affect 450,000 Australian’s per annum. Often these wounds become stuck in the inflammatory phase, and contain excessive numbers of macrophages, which primarily regulate this phase. In order for macrophages to migrate into a wound, production of membrane-type-1 matrix metalloproteinase (MT1-MMP) is upregulated, and it is transported to the cell surface, where it degrades the extracellular matrix (ECM). Inhibiting the intracellular trafficking of MT1-MMP could prevent macrophage migration, and thus could reduce the associated inflammation in chronic wounds, and promote healing. Intracellular transport is partially controlled by SNARE proteins, which regulate fusion steps along the trafficking route. Select SNAREs located on organelles form pairings referred to as trans-SNARE complexes that are unique to the transportation pathway and can be inhibited to identify pathways. Upon lipopolysaccharide (LPS) regulation, MT1-MMP is synthesised de novo in macrophages, unlike in cancer cells where MT1-MMP is constitutively expressed. We have previously shown that MT1-MMP is transported from the Golgi complex through LAMP1-positive late endosome/lysosome compartments to the cell surface. Four membrane fusion SNAREs; VAMP7, VAMP8, Stx4, and SNAP23, mediate the transport of MT1-MMP to the cell surface. We now show that VAMP7 and VAMP8 are located on Rab7-positive late endosomes with MT1-MMP in macrophages, and that both VAMP8 and VAMP7 can form complexes with the surface SNAREs Stx4 and SNAP23, to facilitate the delivery of MT1-MMP for macrophage migration.