In addition to functional changes, activated microglia undergo morphological changes from a resting, ramified morphology to an activated, amoeboid shape. Gangliosides, despite their role as microglial activators, induce microglial ramifications. To identify the cytoskeletal components involved in microglial ramification, we stimulated cells with gangliosides in the absence or presence of cytoskeletal inhibitors and examined the resultant morphological changes.
While LPS-induced ameboid shapes were blocked by all inhibitors, actin inhitibors and microtubule inhibitor, Ganglioside-induced ramifications were blocked by either paclitaxel or nocodazole, inhibitors of microtubule, but not by cytochalasin B or latrunculin B, which are inhibitors of actin polymerization. In contrast to these morphological changes, iNOS expression was suppressed by both inhibitors of actin filament and inhibitors of microtubule. These results indicate that ganglioside-induced ramification is more dependent on tubulin than actin and that both of these cytoskeletal components are involved in iNOS expression.
