Activation of Cell Surface Bound 20S Proteasome Inhibits Vascular Cell Growth and Arteriogenesis

Abstract

Arteriogenesis is an inflammatory process associated with rapid cellular changes involving vascular resident endothelial progenitor cells (VR-EPCs). Extracellular cell surface bound 20S proteasome has been implicated to play an important role in inflammatory processes. In our search for antigens initially regulated during collateral growth mAb CTA 157-2 was generated against membrane fractions of growing collateral vessels. CTA 157-2 stained endothelium of growing collateral vessels and the cell surface of VR-EPCs. CTA 157-2 bound a protein complex (760 kDa) that was identified as 26 kDa α7 and 21 kDa β3 subunit of 20S proteasome in mass spectrometry. Furthermore we demonstrated specific staining of 20S proteasome after immunoprecipitation of VR-EPC membrane extract with CTA 157-2 sepharose beads. Functionally, CTA 157-2 enhanced concentration dependently AMC (7-amino-4-methylcoumarin) cleavage from LLVY (N-Succinyl-Leu-Leu-Val-Tyr) by recombinant 20S proteasome as well as proteasomal activity in VR-EPC extracts. Proliferation of VR-EPCs (BrdU incorporation) was reduced by CTA 157-2. Infusion of the antibody into the collateral circulation reduced number of collateral arteries, collateral proliferation, and collateral conductance in vivo. In conclusion our results indicate that extracellular cell surface bound 20S proteasome influences VR-EPC function in vitro and collateral growth in vivo.

NFAT5 promotes arteriogenesis via MCP‐1‐dependent monocyte recruitment

“…23,29 Compelling evidence has indicated an essential role for monocytes in arteriogenesis. It was evidenced that the 3rd day when NFAT5 increased maximally is also the time when maximal monocyte recruitment occurred.…”

“…It was evidenced that the 3rd day when NFAT5 increased maximally is also the time when maximal monocyte recruitment occurred. 23,29 Compelling evidence has indicated an essential role for monocytes in arteriogenesis. 30,31 Specifically, in the rabbit and mouse hindlimb ischaemia models, pharmacological monocyte depletion led to impaired arteriogenesis which can be rescued by restoring monocyte blood count through the injection of exogenous cells.…”

Determination of the concentration of cathepsin B bySPRI biosensor in children with appendicitis, and its correlation with proteasomes

“…4,12 Proteasome is generally considered a dominating component in protein degradation pathway. 13 Through degrading regulatory proteins or their inhibitors, proteasome regulates many cellular transduction pathways. The ubiquitin-proteasome pathway also offers extremely high substrate specificity and the ability to quickly alter the rate of proteolysis.…”

“…The ubiquitin-proteasome pathway also offers extremely high substrate specificity and the ability to quickly alter the rate of proteolysis. 13 Extracellular proteasomes have been found to circulate in the plasma of patients suffering from a variety of inflammatory, autoimmune and neoplastic diseases. 14−21 In various pathologic conditions, the concentration of circulating proteasomes correlates with disease activity.…”

Immunoproteasome in the blood plasma of children with acute appendicitis, and its correlation with proteasome and UCHL1 measured by SPR imaging biosensors

“…In-vitro studies have shown that proteasome is released by injured endothelial cells, smooth muscle cells of the vessels and tubular epithelial cells [13]. A study by Ito et al [14] demonstrated that extracellular 20S proteasome is not only released from cells but also plays a functional role in physiological processes.…”