Inflammatory cytokine levels are influenced by interactions between THP-1 monocytic, U-373 MG astrocytic, and SH-SY5Y neuronal cell lines of human origin

Abstract

We measured the secretion of interleukin (IL)1β, IL-6 and tumor necrosis factor-α (TNF-α) from human monocytic (THP-1), astrocytic (U-373 MG) and neuronal (SH-SY5Y) cell lines alone and in co-culture, with and without stimulation by a combination of lipopolysaccharide (LPS) plus interferon-γ (IFN-γ) or amyloid β peptide 1–40 (Aβ). LPS+IFN-γ stimulation increased IL-1β secretion 16-fold from THP-1 cells. It increased IL-6 secretion 23-fold from THP-1 cells and 2.5-fold from U-373 MG cells. It increased TNF-α secretion 3.4-fold from THP-1 cells, but did not influence its secretion from U-373 MG cells. It did not affect the secretion of any of the cytokines from SH-SY5Y cells. Aβ stimulation increased IL-6 secretion 2.3-fold from U-373 MG cells but did not influence secretion of IL-1β or TNF-α. Aβ stimulation also failed to influence secretion of any of the cytokines from THP-1 or SH-SY5Y cells. When THP-1 and U-373 MG cells were cocultured, IL-1β and IL-6 secretion, but not TNF-α secretion, were significantly reduced from the levels obtained in independent cultures, suggesting that a mutual suppressive action may occur between microglia and astrocytes.