Effects of antidepressants on IP-10 production in LPS-activated THP-1 human monocytes

Major depressive disorder and cardiovascular disease are common serious illnesses worldwide. Selective serotonin reuptake inhibitors and norepinephrine-dopamine reuptake inhibitors may reduce the mortality of cardiovascular disease patients with comorbid depression. Interferon-γ-inducible protein 10 (IP-10), a type 1 T helper cell (Th1)-related chemokine, contributes to manifestations of atherosclerosis during cardiovascular inflammations; however, the pathophysiological mechanisms linking cardiovascular disease and effective antidepressants have remained elusive. We investigated the in vitro effects of six different classes of antidepressants on the IP-10 chemokine expression in lipopolysaccharide (LPS)-stimulated monocytes, and their detailed intracellular mechanisms. The human monocytes were pretreated with antidepressants (10⁻⁸-10⁻⁵ M) before LPS-stimulation. IP-10 was measured by enzyme-linked immunosorbent assay (ELISA) and then intracellular signaling was investigated using Western blotting and chromatin immunoprecipitation. Fluoxetine and bupropion suppressed LPS-induced IP-10 expression in monocytes, and they had no cytotoxic effects. Furthermore, fluoxetine inhibited LPS-induced IP-10 expression via the mitogen-activated protein kinase (MAPK)-p38 pathway. Fluoxetine and bupropion could not only treat depression but also reduce Th1-related chemokine IP-10 production in human monocytes. Our results may indicate a possible mechanism related to how particular antidepressants reduce the risk of cardiovascular disease.