Unfractionated Heparin Alleviates Human Lung Endothelial Barrier Dysfunction Induced by High Mobility Group Box 1 Through Regulation of P38–GSK3β–Snail Signaling Pathway

Abstract

Background/Aims: The high mobility group box 1 (HMGB1) has been regarded as an important inflammatory mediator. Previous studies showed the involvement of HMGB1 protein in the dysfunction of endothelial barrier function during acute lung injury. However, the molecular mechanism remains unclear. Methods: In this study, we used recombinant human HMGB1 (rhHMGB1) and HMGB1 plasmid to treat human pulmonary microvascular endothelial cell (HPMECs). We examined endothelial permeability by measuring TEER value and HRP flux. Western blot and real-time PCR were used to examined change of endothelial-to-mesenchymal transition (EndoMT) markers and related pathways. Immunofluorescence was used to examine localization and expression of ZO-1 and VE-cadherin. SB203580.was used to block p38 pathway. Unfractionated heparin (UFH) and RAGE siRNA were also used to antagonize the effect of HMGB1. Results: We showed that HMGB1 induced EndoMT with downregulation of ZO-1 and VE-cadherin at both mRNA and protein levels in HPMECs. We also demonstrated that HMGB1 upregulated endothelial permeability by measuring TEER value and HRP flux. Moreover, HMGB1 activated p38/GSK3β/Snail signaling pathway and treatment with p38 inhibitor SB203580 abolished its biological effects. In addition, we found that UFH was able to reverse the effect of HMGB1 on EndoMT and endothelial permeability through inhibition of p38 signaling in a dose-dependent manner. We discovered that RAGE, a membrane receptor of HMGB1, transduced p38/Snail pathway to EndoMT. RAGE siRNA inhibited the effect of HMGB1 induced EndoMT in HPMECs. Conclusion: The present study demonstrated that HMGB1 induced EndoMT through RAGE receptor and p38/GSK3β/Snail pathway. While UFH antagonized HMGB1 and maintained the integrity of the endothelial barrier through p38 inhibition.

The Anticoagulant and Nonanticoagulant Properties of Heparin

“…132 Likewise, heparin was able to alleviate endothelial barrier dysfunction through regulation of p38 MAPK in an inflammatory model induced by the DAMP high mobility group box 1 (HMGB1). 139 While some report heparin does not affect the translocation of NF-kB into the nucleus, 140 other have proposed that it may compete with DNA for NF-κB binding sites. 138,141 Another process in which heparin likely acts through NF-κB is the decreased degranulation of mast cells and other immune cells after exogenous heparin administration.…”

Lung Microvascular Niche, Repair, and Engineering

“…The results indicate that the appropriate chemicals can induce TJ formation and enhance ABB function in an engineered lung. However, in this study, the TEER level achieved in the in vitro culture was at most 10 cm 2 , which is not sufficient for a fully functional lung (Luan et al, 2018).…”

“…Hyaline membranes, lining the alveolar wall and alveolar ducts, consist of protein-rich edema fluid with remnants of necrotic EpCs. In this situation, both tight junctions (TJs) and adherens junctions (AJs), which play critical roles in maintaining the endothelial barrier function, are disrupted (Luan et al, 2018).…”

“…One approach to measure the integrity of the lung vascular niche is the transepithelial/transendothelial electrical resistance (TEER) measurement in a Transwell R assay. This method measures the integrity of TJ dynamics in cell culture models of endothelial and epithelial monolayers (Figure 1) (Neuhaus et al, 2012;Srinivasan et al, 2015;Luan et al, 2018;Yuan et al, 2019). TEER measurements have been used to assess the integrity in such systems as the blood-brain barrier (BBB), gastrointestinal (GI) tract, and pulmonary alveolar septa.…”

A Small Molecule Stabilizer of the MYC G4-Quadruplex Induces Endoplasmic Reticulum Stress, Senescence and Pyroptosis in Multiple Myeloma

“…We observed a gradual increase in HMGB1 protein levels ( Figure 5 a) with D089 treatment over time as well as its translocation from the nucleus to the cytoplasm ( Figure 5 b). Once in the cytoplasm, HMGB1 can activate nuclear factor NFκB and increase its translocation from the cytoplasm to the nucleus [ 43 , 44 , 45 ]. Interestingly, NF-κB is an important transcription factor for gasdermin D (GSDMD) [ 46 ], which has been shown to be essential for pyroptosis and is cleaved by CASP1 [ 25 ].…”