Effects of elicited and pre-existing purified anti-Neu5Gc antibodies on human endothelial cells

Human beings are unable to synthetize the glycolylated neuraminidic acid (Neu5Gc) following a mutation of the CMAH gene and diet induced anti-Neu5Gc antibodies develop in the first year of life. However, because humans can absorb Neu5Gc which deposits at low levels on endothelial cells (EC), activation of endothelium by anti-Neu5Gc has been raised. Understanding whether this interaction contributes to EC normal biology or may induce a potentially detrimental EC activation is crucial, particularly in patients developing elicited anti-Neu5Gc following introduction of animal derived molecules or bio-devices. Ten EC lines were cultured with immune-affinity purified anti-Neu5Gc from normal sera (diet induced) or sera harvested following rabbit-IgG infusion (elicited) anti-Neu5Gc. After a 4h-incubation of Neu5Gc loaded ECs at levels close to those of freshly harvested ECs, ECs were stimulated with both anti-Neu5Gc types and with or without human complement. Anti-Neu5Gc induce a differential expression (DE) of 967 out of expressed 12,208 genes, with transcript accumulation in 93%. Most DE transcripts are shared following activation by pre-existing or elicited anti-Neu5Gc. Compared to ATG pre-existing antibodies, elicited anti-Neu5Gc down-regulated 66 genes, involving master genes such as IL8, ICAM1, MAPKINASES or NFKb1. Furthermore, addition of elicited anti-Neu5Gc to non-heat inactivated sera down-regulated most of the transcripts mobilized by serum alone, including key transcripts involved in apoptosis, fitting with no increase in apoptotic cells. Altogether, the RNA profiling following culture of human ECs and anti-Neu5Gc suggests that pre-existing anti-Neu5Gc contribute to normal human EC homeostasis rather than to an inflammatory oriented transcriptome. Elicited anti-Neu5Gc do not also skew EC transcriptome toward inflammation either, but trigger the release cytokines or chemokines in culture supernatants. Ten endothelial cell (EC) lines were cultured with immune-affinity purified anti-Neu5Gc from normal sera (diet induced) or sera harvested following rabbit-IgG infusion (elicited) anti-Neu5Gc. After a 4h-incubation of Neu5Gc loaded ECs at levels close to those of freshly harvested ECs, ECs were stimulated with both anti-Neu5Gc types and with or without human complement. NOTE: The raw data for the following samples were not provided: GSM3272189: Cmplt_C7 GSM3272190: Cmplt_C6