Moderate Exercise Promotes Human RBC-NOS Activity, NO Production and Deformability through Akt Kinase Pathway

Abstract

BackgroundNitric oxide (NO) produced by nitric oxide synthase (NOS) in human red blood cells (RBCs) was shown to depend on shear stress and to exhibit important biological functions, such as inhibition of platelet activation. In the present study we hypothesized that exercise-induced shear stress stimulates RBC-NOS activation pathways, NO signaling, and deformability of human RBCs.Methods/FindingsFifteen male subjects conducted an exercise test with venous blood sampling before and after running on a treadmill for 1 hour. Immunohistochemical staining as well as western blot analysis were used to determine phosphorylation and thus activation of Akt kinase and RBC-NOS as well as accumulation of cyclic guanylyl monophosphate (cGMP) induced by the intervention. The data revealed that activation of NO upstream located enzyme Akt kinase was significantly increased after the test. Phosphorylation of RBC-NOSSer1177 was also significantly increased after exercise, indicating activation of RBC-NOS through Akt kinase. Total detectable RBC-NOS content and phosphorylation of RBC-NOSThr495 were not affected by the intervention. NO production by RBCs, determined by DAF fluorometry, and RBC deformability, measured via laser-assisted-optical-rotational red cell analyzer, were also significantly increased after the exercise test. The content of the NO downstream signaling molecule cGMP increased after the test. Pharmacological inhibition of phosphatidylinositol 3 (PI3)-kinase/Akt kinase pathway led to a decrease in RBC-NOS activation, NO production and RBC deformability.Conclusion/SignificanceThis human in vivo study first-time provides strong evidence that exercise-induced shear stress stimuli activate RBC-NOS via the PI3-kinase/Akt kinase pathway. Actively RBC-NOS-produced NO in human RBCs is critical to maintain RBC deformability. Our data gain insights into human RBC-NOS regulation by exercise and, therefore, will stimulate new therapeutic exercise-based approaches for patients with microvascular disorders.

Exhaustive Running Exercise Induce Tyrosine Phosphorylation of Band 3 in Rat Erythrocytes

“…These results are in line with a recent report demonstrating that physical exercise positively influences RBC deformability in untrained rodents [4,53]. A recent investigation by Frank Suhr et al indicated that exercise-induced shear stress stimuli activate RBC-NOS via the PI3-kinase/Akt kinase pathway [54]. Activated RBC-NOS generates NO in RBCs, which is mandatory for the beneficial promotion of RBC rheological functions, e.g., deformability [55].…”

Stiffness increase of red blood cells during storage

“…The structure and the interactions between these proteins change during RBC storage due to the degradation of several biochemical parameters, such as SNO and ATP [40][41][42] . The degradation of these biochemical parameters over the RBC storage process has been widely reported, and the depletion of SNO and ATP has been speculated to play important roles in regulating RBCs' mechanical properties 39,[43][44][45] . During RBC storage, the SNO level becomes lower, leading to a lower activity of S-nitrosylation 40 .…”

Muscle Wasting and Early Mobilization in Acute Respiratory Distress Syndrome

“…58,68 Moderate exercise increases antioxidants to counteract oxidative stress, suggesting potential therapeutic benefits with early rehabilitation in the ICU setting. 46,[69][70][71] In CIM there is a preferential loss of myosin relative to actin that cannot be explained merely by immobilization. 72 These structural changes are more likely explained by the direct muscle impairment that underlies CIM and indirect muscle impairment caused by axonal degeneration in CIP.…”