Hypoxia triggers angiogenesis by increasing expression of LOX genes in 3-D culture of ASCs and ECs

Abstract

Objectives: This study aimed to investigate the expression changes of LOX (lysyl oxidase) family genes, VEGFA, and VEGFB under hypoxic conditions in a co-culture system of ASCs (adipose-derived stromal cells) and ECs (endothelial cells).

Materials and methods: ASCs and ECs were co-cultured under hypoxic and normal oxygen conditions in a 1:1 ratio, and the formation of vessel-like was detected at 7 days. The transwell co-culture system was used and cell lysates were collected at 7 days after co-culture in hypoxic and normal oxygen condition. Semi-quantitative PCR was performed to quantify the mRNA expression of VEGFA, VEGFB, and the LOX genes (LOX, LOXL-1, LOXL-2, LOXL-3, and LOXL-4). Expression changes were determined by densitomery.

Results: Enhanced angiogenesis was detected in the co-culture of ASCs and ECs under hypoxic conditions. Among the genes screened, VEGFA, VEGFB, LOXL-1, and LOXL-3 in ECs, both mono-cultured and co-cultured, were significantly enhanced after culturing under hypoxic conditions. In ASCs, VEGFB, LOXL-1, and LOXL-3 were upregulated.

Conclusions: Contact co-culture between ASCs and ECs promotes angiogenesis under hypoxia. LOXL-1 and LOXL-3 expressions were increased in both ASCs and ECs and might play important roles in the enhanced angiogenesis promoted by hypoxia.

Keywords: ASCs; Angiogenesis; ECs; Hypoxia; LOX.