Two Distinct Isoforms of Matrix Metalloproteinase-2 Are Associated with Human Delayed Kidney Graft Function

PLoS One. 2015 Sep 17;10(9):e0136276. doi: 10.1371/journal.pone.0136276. eCollection 2015.

Abstract

Delayed graft function (DGF) is a frequent complication of renal transplantation, particularly in the setting of transplantation of kidneys derived from deceased donors and expanded-criteria donors. DGF results from tubular epithelial cell injury and has immediate and long term consequences. These include requirement for post-transplantation dialysis, increased incidence of acute rejection, and poorer long-term outcomes. DGF represents one of the clearest clinical examples of renal acute ischemia/reperfusion injury. Experimental studies have demonstrated that ischemia/reperfusion injury induces the synthesis of the full length secreted isoform of matrix metalloproteinase-2 (FL-MMP-2), as well as an intracellular N-terminal truncated MMP-2 isoform (NTT-MMP-2) that initiates an innate immune response. We hypothesized that the two MMP-2 isoforms mediate tubular epithelial cell injury in DGF. Archival renal biopsy sections from 10 protocol biopsy controls and 41 cases with a clinical diagnosis of DGF were analyzed for the extent of tubular injury, expression of the FL-MMP-2 and NTT-MMP-2 isoforms by immunohistochemistry (IHC), in situ hybridization, and qPCR to determine isoform abundance. Differences in transcript abundance were related to tubular injury score. Markers of MMP-2-mediated injury included TUNEL staining and assessment of peritubular capillary density. There was a clear relationship between tubular epithelial cell expression of both FL-MMP-2 and NTT-MMP-2 IHC with the extent of tubular injury. The MMP-2 isoforms were detected in the same tubular segments and were present at sites of tubular injury. qPCR demonstrated highly significant increases in both the FL-MMP-2 and NTT-MMP-2 transcripts. Statistical analysis revealed highly significant associations between FL-MMP-2 and NTT-MMP-2 transcript abundance and the extent of tubular injury, with NTT-MMP-2 having the strongest association. We conclude that two distinct MMP-2 isoforms are associated with tubular injury in DGF and offer novel therapeutic targets for the prevention of this disorder.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Capillaries / metabolism
  • Delayed Graft Function / enzymology*
  • Delayed Graft Function / genetics
  • Delayed Graft Function / metabolism
  • Delayed Graft Function / pathology
  • Epithelial Cells / metabolism
  • Female
  • Gene Expression Regulation, Enzymologic
  • Humans
  • Kidney Transplantation*
  • Kidney Tubules / blood supply
  • Kidney Tubules / injuries
  • Kidney Tubules / metabolism
  • Kidney Tubules / pathology
  • Male
  • Matrix Metalloproteinase 2 / genetics
  • Matrix Metalloproteinase 2 / metabolism*
  • Middle Aged
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Up-Regulation

Substances

  • Protein Isoforms
  • RNA, Messenger
  • Matrix Metalloproteinase 2