Hyaluronidase expression in human skin fibroblasts

Hyaluronidase activity has been detected for the first time in normal human dermal fibroblasts (HS27), as well as in fetal fibroblasts (FF24) and fibr osarcoma cells (HT1080). Enzymatic activity was secreted predominantly into the culture media, with minor amounts of activity associated with the cell layer. In both classes of fibroblasts, hyaluronidase expression was conflu ence-dependent, with highest levels of activity occurring in quiescent, pos t-confluent cells. However, in the fibrosarcoma cell cultures, expression w as independent of cell density. The enzyme had a pH optimum of 3.7 and on h yaluronan substrate gel zymography, activity occurred as a single band corr esponding to an approximate molecular size of 57 kDa. The enzyme could be i mmunoprecipitated in its entirety using monoclonal antibodies raised agains t Hyal-1, human plasma hyaluronidase. PCR confirmed that fibroblast hyaluro nidase was identical to Hyal-1. The conclusion by previous investigators us ing earlier technologies that fibroblasts do not contain hyaluronidase acti vity should be reevaluated. (C) 1999 Academic Press.