Acetylcholinesterase conformational states influence nitric oxide mobilization in the erythrocyte

Abstract

In the human erythrocyte, band 3 protein mediates nitric oxide (NO) translocation and its effects are strongly related to phosphorylated/dephosphorylated intracellular states. The metabolism of NO could change in the presence of acetylcholinesterase (AChE). Therefore, the present study was designed to assess the effect of conformational changes in AChE (via N-19 and C-16 antibodies) and enzymatic inhibition/activation of protein kinase C (PKC) in erythrocyte NO mobilization in vitro. Our results show that by inhibiting PKC with cheletrine, impaired erythrocyte NO efflux and s-nitrosoglutathione (GSNO) levels were verified, while PKC's activation by Phorbol 12-myristate 13-acetate had the opposite effect. Those results demonstrate the influence of 4.1R complex and band 3 protein level of phosphorylation on NO efflux and GSNO concentration mediated by PKC inhibition/activation. In addition, the present study shows evidence that conformational changes in AChE promoted by incubation with N-19 and C-16 antibodies alter the enzyme's functional connection to acetylcholine (ACh) (AChE-ACh complex) in an irreversible manner, resulting in impaired GSNO concentration and NO efflux from the erythrocyte. Novel insight into NO metabolism in the erythrocyte is brought with the presented findings allowing new possibilities of modulating NO delivery, possibly involving PKC and AChE conformational alterations in combination.