Tissue inhibitor of metalloproteinases-2 is expressed in the interstitial matrix in adult mouse organs and during embryonic development

Tissue inhibitor of metalloproteinases-2 (TIMP-2) is a member of a family of inhibitors of matrix-degrading metalloproteinases. A better insight into the role of this inhibitor during development and in organ function was obtained by examining the temporospatial expression of TIMP-2 in mice. Northern blot analysis indicated high levels of TIMP-2 mRNA in the lung, skin, reproductive organs, and brain. Lower levels of expression were found in all other organs with the exception of the liver and gastrointestinal tissue, which were negative. In situ hybridization revealed a selective expression in the stromal component of these tissues with complete absence of TIMP-2 mRNA in the epithelium. In the testis, TIMP-2 was present in the Leydig cells, and in the brain, it was expressed in pia matter and in neuronal tissues. TIMP-2 expression in the placenta increased during late gestation and was particularly abundant in spongiotrophoblasts. In mouse embryo (day 10.5-18.5), TIMP-2 mRNA was abundant in mesenchymal tissues that surrounded developing epithelia and maturing skeleton. The pattern of expression significantly differs from that observed with TIMP-1 and TIMP-3, therefore, suggesting specific roles for each inhibitor during tissue remodeling and development.