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  • Hypoxia induced up-regulation of tissue factor is mediated through extracellular RNA activated Toll-like receptor 3-activated protein 1 signalling.

Hypoxia induced up-regulation of tissue factor is mediated through extracellular RNA activated Toll-like receptor 3-activated protein 1 signalling.

Blood cells, molecules & diseases (2020-06-20)
Saumya Bhagat, Indranil Biswas, Rehan Ahmed, Gausal A Khan
ABSTRACT

Sterile Inflammation (SI), a condition where damage associated molecular patterns (DAMPs) released from dying cells, leads to TLR (Toll-like receptor) activation and triggers hypoxemia in circulation leading to venous thrombosis (VT) through tissue factor (TF) activation, but its importance under acute hypoxia (AH) remains unexplored. Thus, we hypothesized that eRNA released from dying cells under AH activates TF via the TLR3-ERK1/2-AP1 pathway, leading to VT. Animals were exposed to stimulate hypoxia for 0-24 h at standard temperature and humidity. RNaseA and DNase1 were injected immediately before exposure. TLR3 gene silencing was performed through in vivo injection of TLR3 siRNA. 80 μg/kg BW of isolated eRNA and eDNA were injected 6 h prior to sacrifice. Antigens of TF pathway were determined by ELISA and TF activity by a chromogenic assay. AH exposure significantly induced release of SI markers i.e. eRNA, eDNA, HMGB1 and upregulated TLR3, ERK1/2 (Extracellular signal-regulated kinases), AP1 (Activator Protein-1) and TF, whereas RNaseA pre-treatment diminished the effect of AH, thus inhibiting TF expression as well as activity during AH. Hence, we propose a possible mechanism of AH-induced TF activation and thrombosis where RNaseA can become the novel focal point in ameliorating therapy for AH induced thrombosis.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Monoclonal Anti-β-Actin antibody produced in mouse, clone AC-74, purified immunoglobulin, buffered aqueous solution
Sigma-Aldrich
MISSION® esiRNA, targeting human TLR3
Millipore
Immobilon®-P PVDF Membrane, 10 sheets, 9 cm x 12 cm, 0.45 µm pore size, Hydrophobic PVDF Transfer Membrane for western blotting.
Sigma-Aldrich
Anti-HMGB1 (HMG1) (C-terminal) antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution