Characterizing potential targets and inhibitors of the metalloproteinase ADAM9

Abstract

ADAM9 (A Disintegrin and Metalloproteinase 9) is a transmembrane protein with a metalloproteinase domain responsible for substrate ectodomain shedding, a process crucial for cell adhesion and signaling. Dysregulation of ADAM9 is linked to inflammation, neurodegenerative diseases, cancer metastasis, and autoimmunity. The Wei lab pioneered a multi-omics approach to identify ADAM9 substrates and targets through RNA sequencing and proteomics, revealing changes in secretion of exosome markers CD9, CD63, and CD81 upon knockdown of ADAM9. Investigations into these hits showed differential secretion into condition media of CD9 and CD63, but not CD81. The Wei lab also screened small-molecule inhibitors and activators of ADAM9 using a medium throughput drug screen, which identified promising inhibitors of ADAM9, however these inhibitors had yet to be tested in cell-culture based models. The inhibition of ADAM9 via Compound 6 has been evaluated by Western blot detection of ADAM9 substrates identified by the Wei lab, IL10RB and ephrin-B1. Building on these findings, this research project aimed to investigate the role of ADAM9 in exosome release and further evaluate the potential of small molecule inhibitors of ADAM9. We found that following ADAM9 knockdown, secretion of CD9, CD63, and CD81 varied unexpectedly suggesting that ADAM9 may regulate exosome release through unexpected or compensatory mechanisms. Treatment with Compound 6 showed varying effects on ADAM9 activity indicating the need for further optimization of western blot conditions and additional validation experiments to confirm Compound 6’s inhibition of ADAM9.