Horobin Jarod T, Sabapathy Surendran, Kuck Lennart, Simmonds Michael J
Menzies Health Institute Queensland, Griffith University, 4222 Gold Coast, Australia.
Biorheology Research Laboratory, Griffith University, 4222 Gold Coast, Australia.
Life (Basel). 2021 Jan 8;11(1):36. doi: 10.3390/life11010036.
Red blood cells (RBC) express a nitric oxide synthase isoform (RBC-NOS) that appears dependent on shear stress for Serine1177 phosphorylation. Whether this protein is equally activated by varied shears in the physiological range is less described. Here, we explored RBC-NOS Serine1177 phosphorylation in response to shear stress levels reflective of in vivo conditions. Whole blood samples were exposed to specific magnitudes of shear stress (0.5, 1.5, 4.5, 13.5 Pa) for discrete exposure times (1, 10, 30 min). Thereafter, RBC-NOS Serine1177 phosphorylation was measured utilising immunofluorescence labelling. Shear stress exposure at 0.5, 1.5, and 13.5 Pa significantly increased RBC-NOS Serine1177 phosphorylation following 1 min ( < 0.0001); exposure to 4.5 Pa had no effect after 1 min. RBC-NOS Serine1177 phosphorylation was significantly increased following 10 min at each magnitude of shear stress (0.5, 1.5, 13.5 Pa, < 0.0001; 4.5 Pa, = 0.0042). Shear stress exposure for 30 min significantly increased RBC-NOS Serine1177 phosphorylation at 0.5 Pa and 13.5 Pa ( < 0.0001). We found that RBC-NOS phosphorylation via shear stress is non-linear and differs for a given magnitude and duration of exposure. This study provides a new understanding of the discrete relation between RBC-NOS and shear stress.
红细胞（RBC）表达一种一氧化氮合酶亚型（RBC-NOS），其丝氨酸1177磷酸化似乎依赖于剪切应力。在生理范围内，这种蛋白质是否同样被不同的剪切力激活，相关描述较少。在此，我们探讨了红细胞一氧化氮合酶（RBC-NOS）丝氨酸1177磷酸化对反映体内情况的剪切应力水平的响应。将全血样本暴露于特定强度的剪切应力（0.5、1.5、4.5、13.5帕斯卡）下，持续不同的暴露时间（1、10、30分钟）。此后，利用免疫荧光标记法测量RBC-NOS丝氨酸1177的磷酸化情况。在1分钟后，暴露于0.5、1.5和13.5帕斯卡的剪切应力下，RBC-NOS丝氨酸1177磷酸化显著增加（<0.0001）；暴露于4.5帕斯卡1分钟后无影响。在每个剪切应力强度下（0.5、1.5、13.5帕斯卡，<0.0001；4.5帕斯卡，=0.0042），10分钟后RBC-NOS丝氨酸1177磷酸化显著增加。暴露于30分钟的剪切应力后，0.5帕斯卡和13.5帕斯卡下RBC-NOS丝氨酸1177磷酸化显著增加（<0.0001）。我们发现，通过剪切应力引起的RBC-NOS磷酸化是非线性的，且对于给定的暴露强度和持续时间存在差异。本研究为RBC-NOS与剪切应力之间的离散关系提供了新的认识。
