Different signaling pathways involved in the anti-inflammatory effects of unfractionated heparin on lipopolysaccharide-stimulated human endothelial cells

Abstract

Background: There is a complex interplay between inflammatory response and coagulation in sepsis. Heparin is used as a recognized anticoagulant and possesses multiple biological properties that possibly affect sepsis. This study aimed to determine the possible signaling pathways involved in the anti-inflammatory effects of unfractionated heparin (UFH) on lipopolysaccharide (LPS)-stimulated human pulmonary microvascular endothelial cells (HPMECs).Methods: HPMECs were transfected with siRNA targeting IκB-α. Cells were treated with UFH (0.01 U/ml~10 U/ml) 15 min before adding LPS (10 μg/ml). We detected the markers of systemic inflammatory response. Release of interleukin (IL)-6, IL-8 were evaluated at 3 h by ELISA and at 1 h by qRT-PCR. After 1 h, nuclear factor-κB (NF-κB) as well as phosphorylated inhibitor κB-α (IκB-α), signal transducer and activator of transcription-3 (STAT3) and ERK1/2, JNK, p38 mitogen-activated protein kinase (MAPK) expressions were evaluated by Western blot. DNA binding was conducted to further prove the activation of NF-κB pathway.Results: In HPMECs, UFH obviously inhibited LPS-stimulated production of IL-6 and IL-8, especially in 10 U/ml. UFH inhibited LPS-induced phosphorylation of IκB-α, ERK1/2, JNK, p38 MAPK and STAT3. UFH also suppressed LPSstimulated nuclear translocation of NF-κB. Importantly, transfection with siRNA targeting IκB-α induced more obvious inflammatory response. UFH suppressed cytokines production and phosphorylation of different signaling pathways in IκB-α silencing cells.Conclusion: These results demonstrate that UFH exerts the anti-inflammatory effects on LPS-stimulated HPMECs by different signaling pathways.

COVID-19 and thrombosis: From bench to bedside

“…Finally, as discussed above, there is evidence for direct endothelial damage by the virus with cytokine production, release of cytoplasmic vWF, tissue-type plasminogen activator and urokinase plasminogen activator. Plasmin activation may partially explain the syndrome resulting elevated D-Dimer levels [ 79 , 81 ].…”

Heparin as a therapy for COVID-19: current evidence and future possibilities

“…The proinflammatory transcription factor nuclear factor-κB (NF-κB), which has been found to be involved in the pathogenesis of SARS-CoV, the virus underlying the 2003 severe acute respiratory syndrome (SARS) epidemic ( 16 ), leads to the production of downstream inflammatory cytokines and other immune response proteins including tumor necrosis factor-α (TNF-α), IL-1β, IL-6, and IL-8 ( 13 , 47 ). Heparin has been observed to directly dampen NF-κB signaling in LPS-stimulated human endothelial cells and human monocytes ( 21 ). Similarly, a synthetic heparin-like drug has recently been developed that neutralizes high mobility group box 1 (HMGB1; 5 ), a proinflammatory mediator that is known to play a role in the pathogenesis of viral infections ( 15 ).…”

Fibrinogen and D-dimer variances and anticoagulation recommendations in Covid-19: current literature review

“…Conversely, a retrospective study has already tested the efficacy of anticoagulant therapy in Covid-19 and resulted in a reduction in mortality when D-dimer exceeded 3.0μg/mL (32.8% vs. 52.4%, p= 0.017) 23 . The results may be due to the hypercoagulable state of the disease, or the anti-inflammatory effect of anticoagulation, or the combination of these two reasons 33 . An interesting study on tissue plasminogen activator (tPA) use for Covid-19 induced ARDS has shown amelioration in the PaO2/FiO2 ratio, which may be considered a clue for the necessity of anticoagulation prior to ARDS onset34 .…”