Cardiotrophin-1 Induces Tumor Necrosis Factor Synthesis in Human Peripheral Blood Mononuclear Cells

Abstract

Chronic heart failure (CHF) is associated with elevated concentrations of tumor necrosis factor (TNF) and cardiotrophin-1 (CT-1) and altered peripheral blood mononuclear cell (PBMC) function. Therefore, we tested whether CT-1 induces TNF in PBMC of healthy volunteers. CT-1 induced in PBMC TNF protein in the supernatant and TNF mRNA in a concentration- and time-dependent manner determined by ELISA and real-time PCR, respectively. Maximal TNF protein was achieved with 100 ng/mL CT-1 after 3–6 hours and maximal TNF mRNA induction after 1 hour. ELISA data were confirmed using immunofluorescent flow cytometry. Inhibitor studies with actinomycin D and brefeldin A showed that both protein synthesis and intracellular transport are essential for CT-1 induced TNF expression. CT-1 caused a dose dependent nuclear factor (NF) B translocation. Parthenolide inhibited both NFB translocation and TNF protein expression indicating that NFB seems to be necessary. We revealed a new mechanism for elevated serum TNF concentrations and PBMC activation in CHF besides the hypothesis of PBMC activation by bacterial translocation from the gut.