Induction of Apoptosis by Epigallocatechin Gallate and Autophagy Inhibitors in a Mouse Macrophage-like Cell Line

Abstract

We have previously reported that lignin carbohydrate complex and E. coli lipopolysaccharide (LPS), but not their precursors or (-)-epigallocatechin-3-gallate (EGCG), enhanced the nitric oxide (NO), citrulline and asparagines production by the mouse-macrophage-like cell line Raw264.7. Here the EGCG inhibition of NO production by LPS-stimulated Raw264.7 cells is reported. EGCG induced apoptotic cell death characterized by internucleosomal DNA fragmentation, whereas it inhibited the formation of secondary lysosomes and autophagosomes detected as granular dot-like distribution of acridine orange and microtubule-associated protein light chain 3 fused with green fluorescent protein (LC3-GFP). Autophagy inhibitors such as 3-methyladenine and bafilomycin A1 induced apoptotic cell death in the Raw264.7 cells. The inhibition of macrophage NO production by EGCG may be due to the apoptosis induction coupled with autophagy inhibition.