Regulation of gelatinases in mid and astrocyte cell cultures by plant lectins

The effects of 25 recently discovered plant lectins on cell proliferation a nd enzyme release were compared to those of previously known lectins on rat microglia and astrocyte cell cultures. A dose-dependent proliferation of m icroglial cells, but not of astrocytes, was induced by seven lectins, where as five lectins showed dose-dependent cytotoxicity on both microglia and as trocyte cell cultures. The activity of gelatinase B (MMP-9) was strongly in creased in microglial cells by the aforementioned seven lectins, by concana valin A, and by phytohemagglutinin (PHA-E4), whereas gelatinase A (MMP-2) r emained at constitutive levels. The five cytotoxic lectins decreased the ac tivity of gelatinase B in microglia and of gelatinase A in astrocytes, in a dose-dependent manner. The lectin wheat germ agglutinin induced a decrease in gelatinase B activity in microglia, but stimulated gelatinase A and B a ctivity in astrocytes. These results indicate that lectins possess neuromod ulatory effects that may motivate the study of their effects on central ner vous system (CNS) function in vivo. This, in turn, may lead to better insig ht into whether lectin or lectin-like molecules can interact with glial cel ls, and whether they have a role in acute toxicity and in multifactorial di seases in which environmental factors may play a role. (C) 1999 Wiley-Liss, Inc.