Single-stranded polyinosinic acid oligonucleotides trigger leukocyte production of proteins belonging to fibrinolytic and coagulation cascades

Abstract

The present study assessed the inductory effects of ds- and ssRNA on the leukocyte production of proteins belonging to fibrinolytic and coagulation cascades. Murine splenocytes were stimulated with dsRNA [polyinosinic:polycytidylic acid (polyIC)] and ssRNA sequences [polyinosinic acid (polyI), polycytidylic acid (polyC), and polyuridylic acid (polyU)]. The expression of plasminogen (Plg), tissue factor (TF), IL-6, and IFN-alpha was assessed. Intracellular transduction mechanisms activated by oligonucleotides were evaluated using specific inhibitors of signaling pathways and genetically modified mice. polyIC efficiently and dose-dependently induced the expression of Plg, IL-6, and IFN-alpha, whereas TF was not induced by polyIC. polyI was unable to trigger IFN-alpha production, and it was efficiently inducing Plg and TF. IFN-alphaR and dsRNA-dependent protein kinase signaling were not required for the polyI-induced production of Plg or TF. Neither polyU nor polyC induced the expression of Plg or TF. Importantly, the presence of U- and C-nucleotide strands in the dsRNA significantly reduced expression of Plg and TF compared with polyI alone. Exposure of splenocytes to polyI activated the NF-kappaB pathway followed by the expression of TF and IL-6. In contrast, Plg production did not require NF-kappaB, was only partly down-regulated by p38 MAPK inhibitor, and was efficiently inhibited by insulin, indicating a different mechanism for its induction. ssRNA exerts its TF-generating properties through NF-kappaB activation in an IFN-alpha-independent manner. The expression of fibrinolytic versus coagulation proteins is regulated through distinctly different transduction pathways. As fibrinolytic and coagulation cascades are important components of inflammatory homeostasis, these findings might have importance for development of new, targeted therapies.

Coagulation, Protease-Activated Receptors, and Viral Myocarditis

“…Interestingly, the dsRNA analog, polyinosinic-polycytidylic acid (poly IC), is a synthetic ligand for TLR3 and when administered to mice induces TF expression in endothelial cells and a hypercoagulative state [38]. Zare et al observed that TF expression in murine splenocytes was increased by ssRNA (poly I) but not dsRNA (poly IC) [39]. This induction was MyD88-dependent and IFN-independent [39].…”

“…Zare et al observed that TF expression in murine splenocytes was increased by ssRNA (poly I) but not dsRNA (poly IC) [39]. This induction was MyD88-dependent and IFN-independent [39]. Furthermore, type I and III IFN expression was associated with activation of coagulation [40].…”

Polyinosinic acid decreases sequestration and improves systemic therapy of measles virus

“…It is important to point out that poly(I) is a single stranded RNA and is less effective at inducing IFN-alpha in leukocytes compared to double stranded small RNA polyI:C. 56 Systemic administration of poly(I) at 0.2 mg per mouse induced no observable toxicity in livers of athymic mice although transient higher serum levels of IL-6, MCP-1 and TNF-α were detected. 55 Alternative ligands of scavenger receptor A could be tested in lieu of poly(I) if clinical testing is desired, for example, fucoidan 46, 57 or using an alternative strategy to transiently eliminate macrophages using clodronate loaded liposomes.…”

Traumatic Abdominal Solid Organ Injury Patients Might Benefit From Thromboelastography-Guided Blood Component Therapy

“…It is well known that the liver and spleen play important roles in the homeostasis of coagulation pathways [15, 16]. Traumatic liver and/or spleen injuries could significantly affect coagulopathy.…”