Regional Centre for Biotechnology; National Capital Region Biotech Science Cluster, Faridabad, India.
Translational Health Science Technology Institute; National Capital Region Biotech Science Cluster, Faridabad, India.
EBioMedicine. 2021 Nov;73:103672. doi: 10.1016/j.ebiom.2021.103672. Epub 2021 Nov 2.
Phospho-Akt1 (pAkt1) undergoes prolyl hydroxylation at Pro125 and Pro313 by the prolyl hydroxylase-2 (PHD2) in a reaction decarboxylating α-ketoglutarate (αKG). We investigated whether the αKG supplementation could inhibit Akt-mediated activation of platelets and monocytes, in vitro as well as in vivo, by augmenting PHD2 activity.
We treated platelets or monocytes isolated from healthy individuals with αKG in presence of agonists in vitro and assessed the signalling molecules including pAkt1. We supplemented mice with dietary αKG and estimated the functional responses of platelets and monocytes ex vivo. Further, we investigated the impact of dietary αKG on inflammation and thrombosis in lungs of mice either treated with thrombosis-inducing agent carrageenan or infected with SARS-CoV-2.
Octyl αKG supplementation to platelets promoted PHD2 activity through elevated intracellular αKG to succinate ratio, and reduced aggregation in vitro by suppressing pAkt1(Thr308). Augmented PHD2 activity was confirmed by increased hydroxylated-proline and enhanced binding of PHD2 to pAkt in αKG-treated platelets. Contrastingly, inhibitors of PHD2 significantly increased pAkt1 in platelets. Octyl-αKG followed similar mechanism in monocytes to inhibit cytokine secretion in vitro. Our data also describe a suppressed pAkt1 and reduced activation of platelets and leukocytes ex vivo from mice supplemented with dietary αKG, unaccompanied by alteration in their number. Dietary αKG significantly reduced clot formation and leukocyte accumulation in various organs including lungs of mice treated with thrombosis-inducing agent carrageenan. Importantly, in SARS-CoV-2 infected hamsters, we observed a significant rescue effect of dietary αKG on inflamed lungs with significantly reduced leukocyte accumulation, clot formation and viral load alongside down-modulation of pAkt in the lung of the infected animals.
Our study suggests that dietary αKG supplementation prevents Akt-driven maladies such as thrombosis and inflammation and rescues pathology of COVID19-infected lungs.
Study was funded by the Department of Biotechnology (DBT), Govt. of India (grants: BT/PR22881 and BT/PR22985); and the Science and Engineering Research Board, Govt. of India (CRG/000092).
磷酸化 Akt1(pAkt1)在脯氨酰羟化酶-2(PHD2)的作用下，于脯氨酸 125 和 313 位发生羟化反应，同时脱羧α-酮戊二酸(αKG)。我们研究了通过增强 PHD2 活性，αKG 补充是否能抑制血小板和单核细胞中 Akt 介导的激活，无论是在体外还是体内。
我们用激动剂在体外处理来自健康个体的血小板或单核细胞，并评估包括 pAkt1 在内的信号分子。我们用饮食αKG 补充小鼠，并估计血小板和单核细胞的体外功能反应。此外，我们研究了饮食αKG 对用致血栓剂角叉菜胶处理或感染 SARS-CoV-2 的小鼠肺部炎症和血栓形成的影响。
辛基 αKG 补充物通过提高细胞内 αKG 与琥珀酸的比例，促进血小板中的 PHD2 活性，并通过抑制 pAkt1(Thr308)减少体外聚集。在αKG 处理的血小板中，羟脯氨酸增加和 PHD2 与 pAkt 结合增强证实了 PHD2 活性增强。相反，PHD2 的抑制剂显著增加了血小板中的 pAkt1。辛基-αKG 在单核细胞中也遵循类似的机制，抑制体外细胞因子的分泌。我们的数据还描述了饮食αKG 补充物可抑制血小板和白细胞的 pAkt1 减少和体外激活，而不改变其数量。饮食αKG 可显著减少包括用致血栓剂角叉菜胶处理的小鼠的肺部在内的各种器官中的血栓形成和白细胞积聚。重要的是，在感染 SARS-CoV-2 的仓鼠中，我们观察到饮食 αKG 对受感染肺部炎症的显著挽救作用，白细胞积聚、血栓形成和病毒载量显著减少，同时感染动物肺部的 pAkt 下调。
我们的研究表明，饮食αKG 补充可预防 Akt 驱动的疾病，如血栓形成和炎症，并可挽救 COVID19 感染肺部的病理。
该研究由生物技术部(DBT)，印度政府(拨款：BT/PR22881 和 BT/PR22985)；以及科学与工程研究委员会，印度政府(CRG/000092)资助。
