Rabbit Anti-Human Bcl10 monoclonal antibody, clone TO85-15

The pattern recognition receptors TLR2 and Dectin-1 play key roles in coordinating the responses of macrophages and dendritic cells (DC) to fungi. Induction of proinflammatory cytokines is instructed by signals from both TLR2 and Dectin-1. A recent report identified a role for CARD9 in innate anti-fungal responses, demonstrating CARD9-Bcl10-mediated activation of NF-kappa B and proinflammatory cytokine induction in murine bone marrow-derived DC stimulated via Dectin-1. We now report that Dectin-1-CARD9 signals fail to activate NF-kappa B and drive TNF-alpha induction in murine bone marrow-derived macrophages. However, priming of bone marrow-derived macrophages with GM-CSF or IFN-gamma permits Dectin-1-CARD9-mediated TNF-alpha induction. Analysis of other macrophage/DC populations revealed further variation in the ability of Dectin-1-CARD9 signaling to drive TNF-alpha production. Resident peritoneal cells and alveolar macrophages produce TNF-alpha upon Dectin-1 ligation, while thioglycol-late-elicited peritoneal macrophages and FIt3L-derived DC do not. We present data demonstrating that CARD9 is recruited to phagosomes via its CARD domain where it enhances TLR-induced cytokine production even in cells in which Dectin-1 is insufficient to drive cytokine production. In such cells, Dectin-1, CARD9, and Bcl10 levels are not limiting, and data indicate that these cells express additional factors that restrict Dectin-1-CARD9 signaling for TNF-alpha induction. The Journal of Immunology, 2009, 182: 1146-1154.

We reported previously that a signaling pathway consisting of G(i)-Ras-NF-kappa B mediates lysophosphatidic acid (LPA)-induced urokinase plasminogen activator (uPA) upregulation in ovarian cancer cells. However, it is not clear what signaling components link Ras to nuclear factor (NF)-kappa B for this LPA-induced event. In the present study, we found that treatment of protein kinase C (PKC) inhibitors including conventional PKC (cPKC) inhibitor Go6976 abolished LPA-induced uPA upregulation in ovarian cancer cell lines tested, indicating the importance of cPKC activity in this LPA-induced event. Indeed, LPA stimulation led to the activation of PKC alpha and Ras-PKC alpha interaction. Although constitutively active mutants of PKC alpha (a cPKC), PKC theta (a novel PKC (nPKC)) and PKC zeta (an atypical PKC (aPKC)) were all able to activate NF-kappa B and upregulate uPA expression, only dominant-negative PKCa mutant attenuated LPA-induced NF-kappa B activation and uPA upregulation. These results suggest that PKCa, rather than PKC isoforms in other PKC classes, participates in LPA-induced NF-kappa B activation and uPA upregulation in ovarian cancer cells. To determine the signaling components downstream of PKC alpha mediating LPA-induced uPA upregulation, we showed that forced expression of dominant-negative CARMA3 or silencing CARMA3, Bcl10 and MALT1 with specific siRNAs diminished these LPA-induced events. Furthermore, we demonstrated that PKC alpha/CARMA3 signaling axis is important in LPA-induced ovarian cancer cell in vitro invasion.