| First Author | Jeong S | Year | 2012 |
| Journal | Am J Pathol | Volume | 180 |
| Issue | 5 | Pages | 2028-39 |
| PubMed ID | 22440257 | Mgi Jnum | J:183472 |
| Mgi Id | MGI:5318796 | Doi | 10.1016/j.ajpath.2012.01.025 |
| Citation | Jeong S, et al. (2012) Interaction of clusterin and matrix metalloproteinase-9 and its implication for epithelial homeostasis and inflammation. Am J Pathol 180(5):2028-39 |
| abstractText | Uncontrolled increases of matrix metalloproteinase-9 (MMP-9) activity have been causally linked to epithelial barrier disruption and severe symptoms of inflammatory diseases such as dry eye (DE). The data presented here show that the anti-inflammatory, cytoprotective intracellular and extracellular chaperone protein clusterin (CLU) interacts with MMP-9 both inside and outside epithelial cells. CLU bound very strongly to active MMP-9, with an affinity constant K(D) of 2.63 nmol/L. Unexpectedly, CLU had a much higher affinity for pro-MMP-9 than for active MMP-9 or pro-MMP-2, requiring the N-terminal propeptide domain of pro-MMP-9. The significance of the interaction between CLU and MMP-9 was demonstrated by the observation that CLU prevents stress-induced MMP-9 aggregation and inhibits MMP-9 enzymatic activity. Furthermore, CLU inhibited MMP-9-mediated disintegration of the tight junction structure formed between human epithelial cells. Additionally, CLU inhibited enzymatic activities of MMP-2, MMP-3, and MMP-7. Treatment with proinflammatory cytokines, which are known to increase MMP-9 transcription under inflammatory conditions, reduced the expression of CLU in human epithelial cells. Similarly, in a mouse model of human DE, inflammatory stress depleted CLU in the ocular surface epithelium but allowed MMP-9 to prevail therein. The present results thus provide novel insights into previously unrecognized mechanisms by which CLU maintains fluid-epithelial interface homeostasis, thereby preventing the onset of inflammatory conditions, especially where MMP-9 is actively involved. |
