Fas-activated apoptosis and apoptosis mediators in human trabecular meshwork cells

A gradual loss of cells occurs within the human trabecular meshwork during normal aging and appears to be increased in patients with primary open-angl e glaucoma. The exact mechanism by which cells are lost in either condition is not known, however phagocytosis, cell migration and cell death have bee n suggested. Apoptosis is one method by which cell death can occur. We have examined the modulators for apoptosis within the human trabecular meshwork using both cell lines and ex-vivo dissected trabecular meshwork tissues ob tained from normal donors. Using RT-PCR it was shown that mRNA for several modulators of apoptosis (Fas, Bcl-2, Bcl-xl, Pax, and ICE) are expressed by both cell lines and ex-vivo tissues. Apoptosis was stimulated to occur by treating cell lines with a monoclonal antibody (IgM) to Pas. Apoptosis was verified via morphological changes to the cells, transferase-mediated dUTP nick-end labeling TUNEL Immunofluorescence, and DNA laddering. Control cell s exposed to IgM did not undergo apoptosis. These results represent the fir st report of apoptosis modulators within the human trabecular meshwork and demonstrate that human trabecular meshwork cells can be stimulated to under go apoptosis via the Fas/FasL pathway. (C) 1999 Academic Press.