Cryptococcus neoformans glucuronoxylomannan induces macrophage apoptosis mediated by nitric oxide in a caspase-independent pathway

LAURA S. CHIAPELLO, JOSÉ L. BARONETTI, ANA P. GARRO, MARÍA F. SPESSO, AND DIANA T. MASIH

OXFORD UNIV PRESS

Año: 2008 vol. 20 p. 1527 - 1527

p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: justify; mso-layout-grid-align: none">Glucuronoxylomannan (GXM) is the major component of Cryptococcus capsular polysaccharide, which represents an essential virulence factor for this yeast. Cryptococcus neoformans infections in immunocompetent rats are associated with inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production by macrophages. This study demonstrates in vitro and in vivo that GXM promotes iNOS expression with NO production in rat macrophages. GXM also induced macrophage apoptosis after 48 h of culture, with this phenomenon being prevented by the iNOS inhibitor, aminoguanidine. The NO-induced macrophage apoptosis triggered by GXM was dependent on interactions with CD18, Fcg receptor II and protein kinase C activation, without participation of t