Diminished Matrix Metalloproteinase 2 (MMP-2) in Ectomesenchyme-Derived Tissues of the Patch Mutant Mouse: Regulation of MMP-2 by PDGF and Effects on Mesenchymal Cell Migration

Abstract

Platelet-derived growth factors (PDGF) regulate cell proliferation, survival, morphology, and migration, as well as deposition and turnover of the extracellular matrix. Important roles for the A form of PDGF (PDGF-A) during connective tissue morphogenesis have been highlighted by the murine Patch mutation, which includes a deletion of the alpha subunit of the PDGF receptor. Homozygous (Ph/Ph) embryos exhibit multiple connective tissue defects including cleft face (involving the first branchial arch and frontonasal processes), incomplete heart septation, and heart valve abnormalities before they die in utero. Analyses of the cell biology underlying the defects in Ph/Ph embryos have revealed a deficit in a matrix metalloproteinase (MMP-2) and one of its activators (MT-MMP) that are likely to be involved in cell migration and tissue remodeling, two processes necessary for normal cardiac and craniofacial development. Morphogenesis of these structures requires infiltration of ectomesenchymal precursors and their subsequent deposition and remodeling of extracellular matrix components. First branchial arch and heart tissue from E10.5 embryos were examined by gelatin zymography and RT-PCR in order to characterize the expression of MMPs in these tissues. Of the MMPs examined, only MMP-2 and one of its activators, MT-MMP, were expressed in the first arch and heart at this stage of development. Tissues from Ph/Ph embryos exhibited a significant decrease in both MMP-2 and MT-MMP compared to tissues from normal embryos of the same developmental stage. In order to assess whether this decrease affects the motile activity of mesenchymal cells, cell migration from Ph/Ph branchial arch explants was compared to migration from normal arch tissue and found to be significantly less. In addition, the migratory ability of branchial arch cells from normal explants could be reduced in a similar manner using a specific MMP inhibitor. Although it is still unclear whether the MMP-2 reduction is a direct result of the absence of response of Ph/Ph cells to PDGF-A treatment of normal branchial arch cells in vitro with recombinant PDGF-AA significantly upregulated MMP-2 protein. Together, these results suggest that PDGF-A regulates MMP-2 expression and activation during normal development and that faulty proteinase expression may be at least partially responsible for the developmental defects exhibited by Ph/Ph embryos.

Molecular mechanisms of the effect of TGF-β1 on U87 human glioblastoma cells

“…Ablation of the PDGF-receptor α-subunit enhances the formation and migration of mesenchymal-like cells, and decreases MMP2 activity (62). VEGF is understood to be associated with PDGF and induces angiogenesis, which also causes EMT (63).…”

MMP‐2 plays an essential role in producing epithelial‐mesenchymal transformations in the avian embryo

“…Direct inhibition of MMPs in mouse neural crest cultures (Robbins et al, 1999) or in chick neural crest cultures (Cai and Brauer, 2002) further show that this class of matrix-degrading enzymes may stimulate motility. Moreover, in the mouse mutant Patch, in which craniofacial mesenchyme does not disperse properly, MMP-2 activity is depressed (Robbins et al, 1999). Of interest, our cell culture studies and embryo studies suggest that once neural crest cells are fully mesenchymal, they are not affected by loss of MMP-2 activity.…”

“…Previous studies also showed that MMP-2 is expressed in migrating chick endocardial cushion cells (Alexander et al, 1997;Cai et al, 2000). MMP-2 is expressed in the mesenchyme of the mouse embryo Robbins et al, 1999), although the cranial neural crest was the only MMP-2-expressing cell population in those studies that overlapped with chicken MMP-2 expression. Direct inhibition of MMPs in mouse neural crest cultures (Robbins et al, 1999) or in chick neural crest cultures (Cai and Brauer, 2002) further show that this class of matrix-degrading enzymes may stimulate motility.…”

“…MMP-2 is expressed in the mesenchyme of the mouse embryo Robbins et al, 1999), although the cranial neural crest was the only MMP-2-expressing cell population in those studies that overlapped with chicken MMP-2 expression. Direct inhibition of MMPs in mouse neural crest cultures (Robbins et al, 1999) or in chick neural crest cultures (Cai and Brauer, 2002) further show that this class of matrix-degrading enzymes may stimulate motility. Moreover, in the mouse mutant Patch, in which craniofacial mesenchyme does not disperse properly, MMP-2 activity is depressed (Robbins et al, 1999).…”

Differential Expression of Extracellular Matrix and Growth Factors by Embryoid Bodies in Hydrodynamic and Static Cultures

“…S3). [26][27][28][29] In this work, we have further demonstrated that hydrodynamics might influence ESC differentiation through temporal modulation of ECM and GF gene and protein expression. Although our results illustrate similar kinetic profiles between static and rotary culture systems for many of the specific genes examined, the rotary environment elicited increases in expression of a larger subset of genes throughout the time course of EB analysis.…”