Figure 14.
MMP‐2 is a negative regulator of the release of active sPLA2 from the myocardium. A, Scheme of experimental protocol. B, sPLA2 activity released ex vivo from WT or Mmp2−/− myocardial specimens. *P≤0.05 vs WT, t test. C, Left: sPLA2 activity released ex vivo from Mmp2−/− myocardial specimens from mice transduced with either AdMMP‐2 or AdGFP. †P≤0.05 vs Mmp2−/−+AdGFP, t test. Right: To measure the molecular weight of released sPLA2, the myocardial releasates were pooled and resolved by nonreducing SDS‐PAGE followed by sPLA2 activity assay. Data corresponds to an incubation time of 40 minutes for Mmp2−/− mice transduced with AdGFP or AdMMP‐2. D, sPLA2 activity released from ex vivo heart sections in the absence and presence of Brefeldin A (70 μmol/L), a drug that blocks the endoplasmic reticulum to Golgi transition along the classical secretory pathway. ‡P≤0.05 vs Mmp2+/−−Brefeldin A. §P≤0.05 vs Mmp2−/−+Brefeldin A. All pairwise multiple‐comparison procedures (Holm–Sidak method). Data correspond to an incubation time of 100 minutes for nontransduced WT and Mmp2−/− mice. AdGFP indicates green fluorescent protein–expressing adenovirus; AdMMP, MMP‐2‐encoding adenovirus; MMP, matrix metalloproteinase; MW, molecular weight; SDS‐PAGE, sodium‐dodecylsulfate polyacrylamide gel electrophoresis; sPLA2, secreted phospholipase A2; WT, wild‐type.