Nitric oxide synthetic pathway and cGMP levels are altered in red blood cells from end-stage renal disease patients

• Published in: Molecular and cellular biochemistry Vol. 417; no. 1-2; pp. 155 - 167
• Main Authors: Di Pietro, Natalia, Giardinelli, Annalisa, Sirolli, Vittorio, Riganti, Chiara, Di Tomo, Pamela, Gazzano, Elena, Di Silvestre, Sara, Panknin, Christina, Cortese-Krott, Miriam M., Csonka, Csaba, Kelm, Malte, Ferdinandy, Péter, Bonomini, Mario, Pandolfi, Assunta
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2016; Springer; Springer Nature B.V
• Subjects: Aged; Bioavailability; Biochemistry; Biomedical and Life Sciences; Calcium; Calmodulin - metabolism; Cardiology; Chronic kidney failure; Cyclic GMP - metabolism; Cyclic guanosine monophosphate; Drug resistance; Endothelium; Enzymes; Erythrocytes; Erythrocytes - metabolism; Erythrocytes - pathology; Female; Heat shock proteins; HSP90 Heat-Shock Proteins - metabolism; Humans; Insulin; Kidney diseases; Kidney Failure, Chronic - metabolism; Kidney Failure, Chronic - pathology; Kidney Failure, Chronic - therapy; Life Sciences; Male; Medical Biochemistry; Middle Aged; Multidrug Resistance-Associated Proteins - biosynthesis; Nitric oxide; Nitric Oxide - biosynthesis; Nitric Oxide Synthase Type III - metabolism; Oncology; Type 2 diabetes; End-stage renal disease; cGMP; Nitric oxide synthase; Red blood cells; Nitric oxide
• ISSN: 0300-8177; 1573-4919
• DOI: 10.1007/s11010-016-2723-0

Red blood cells (RBCs) enzymatically produce nitric oxide (NO) by a functional RBC-nitric oxide synthase (RBC-NOS). NO is a vascular key regulatory molecule. In RBCs its generation is complex and influenced by several factors, including insulin, acetylcholine, and calcium. NO availability is reduced in end-stage renal disease (ESRD) and associated with endothelial dysfunction. We previously demonstrated that, through increased phosphatidylserine membrane exposure, ESRD-RBCs augmented their adhesion to human cultured endothelium, in which NO bioavailability decreased. Since RBC-NOS-dependent NO production in ESRD is unknown, this study aimed to investigate RBC-NOS levels/activation, NO production/bioavailability in RBCs from healthy control subjects (C, N  = 18) and ESRD patients ( N  = 27). Although RBC-NOS expression was lower in ESRD-RBCs, NO, cyclic guanosine monophosphate (cGMP), RBC-NOS Serine1177 phosphorylation level and eNOS/Calmodulin (CaM)/Heat Shock Protein-90 (HSP90) interaction levels were higher in ESRD-RBCs, indicating increased enzyme activation. Conversely, following RBCs stimulation with insulin or ionomycin, NO and cGMP levels were significantly lower in ESRD- than in C-RBCs, suggesting that uremia might reduce the RBC-NOS response to further stimuli. Additionally, the activity of multidrug-resistance-associated protein-4 (MRP4; cGMP-membrane transporter) was significantly lower in ESRD-RBCs, suggesting a possible compromised efflux of cGMP across the ESRD-RBCs membrane. This study for the first time showed highest basal RBC-NOS activation in ESRD-RBCs, possibly to reduce the negative impact of decreased NOS expression. It is further conceivable that high NO production only partially affects cell function of ESRD-RBCs maybe because in vivo they are unable to respond to physiologic stimuli, such as calcium and/or insulin.