S1PR1 serves as a viable drug target against pulmonary fibrosis by increasing the integrity of the endothelial barrier of the lung

Idiopathic pulmonary fibrosis(IPF)is a progressive lung disease with unclear etiology and limited treatment options.The median survival time for IPF patients is approximately 2–3 years and there is no effective intervention to treat IPF other than lung transplantation.As important components of lung tissue,endothelial cells(ECs)are associated with pulmonary diseases.However,the role of endothelial dysfunction in pulmonary fibrosis(PF)is incompletely understood.Sphingosine-1-phosphate receptor 1(S1PR1)is a G protein-coupled receptor highly expressed in lung ECs.Its expression is markedly reduced in patients with IPF.Herein,we generated an endothelial-conditional S1pr1 knockout mouse model which exhibited inflammation and fibrosis with or without bleomycin(BLM)challenge.Selective activation of S1PR1 with an S1PR1 agonist,IMMH002,exerted a potent therapeutic effect in mice with bleomycin-induced fibrosis by protecting the integrity of the endothelial barrier.These results suggest that S1PR1 might be a promising drug target for IPF therapy.

Ruscogenin alleviates LPS-triggered pulmonary endothelial barrier dysfunction through targeting NMMHC IIA to modulate TLR4signaling

Pulmonary endothelial barrier dysfunction is a hallmark of clinical pulmonary edema and contributes to the development of acute lung injury(ALI).Here we reported that ruscogenin(RUS),an effective steroidal sapogenin of Radix Ophiopogon japonicus,attenuated lipopolysaccharides(LPS)-induced pulmonary endothelial barrier disruption through mediating non-muscle myosin heavy chain IIA(NMMHC IIA)-Toll-like receptor 4(TLR4)interactions.By in vivo and in vitro experiments,we observed that RUS administration significantly ameliorated LPS-triggered pulmonary endothelial barrier dysfunction and ALI.Moreover,we identified that RUS directly targeted NMMHC IIA on its N-terminal and head domain by serial affinity chromatography,molecular docking,biolayer interferometry,and microscale thermophoresis analyses.Downregulation of endothelial NMMHC IIA expression in vivo and in vitro abolished the protective effect of RUS.It was also observed that NMMHC IIA was dissociated from TLR4 and then activating TLR4 downstream Src/vascular endothelial cadherin(VE-cadherin)signaling in pulmonary vascular endothelial cells after LPS treatment,which could be restored by RUS.Collectively,these findings provide pharmacological evidence showing that RUS attenuates LPS-induced pulmonary endothelial barrier dysfunction by inhibiting TLR4/Src/VE-cadherin pathway through targeting NMMHC IIA and mediating NMMHC IIA-TLR4 interactions.

Hepatocyte growth factor protects pulmonary endothelial barrier against oxidative stress and mitochondria-dependent apoptosis

Background:Pulmonary microvascular endothelial cells(PMVECs)were not complex,and the endothelial barrier was destroyed in the pathogenesis progress of acute lung injury(ALI)/acute respiratory distress syndrome(ARDS).Previous studies have demonstrated that hepatocyte growth factor(HGF),which was secreted by bone marrow mesenchymal stem cells,could decrease endothelial apoptosis.We investigated whether mTOR/STAT3 signaling acted in HGF protective effects against oxidative stress and mitochondria-dependent apoptosis in lipopolysaccharide(LPS)-induced endothelial barrier dysfunction and ALI mice.Methods:In our current study,we introduced LPS-induced PMEVCs with HGF treatment.To investigate the effects of mammalian target of rapamycin(mTOR)/signal transducer and activator of transcription 3(STAT3)pathway in endothelial oxidative stress and mitochondria-dependent apoptosis,mTOR inhibitor rapamycin and STAT3 inhibitor S3I-201 were,respectively,used to inhibit mTOR/STAT3 signaling.Moreover,lentivirus vector-mediatedmTORC1(Raptor)andmTORC2(Rictor)gene knockdown modifications were introduced to evaluatemTORC1 andmTORC1 pathways.Calcium measurement,reactive oxygen species(ROS)production,mitochondrial membrane potential and protein,cell proliferation,apoptosis,and endothelial junction protein were detected to evaluate HGF effects.Moreover,we used the ALI mouse model to observe the mitochondria pathological changes with an electron microscopein vivo.Results:Our study demonstrated that HGF protected the endothelium via the suppression of ROS production and intracellular calcium uptake,which lead to increased mitochondrial membrane potential(JC-1 and mitochondria tracker green detection)and specific proteins(complex I),raised anti-apoptosis Messenger Ribonucleic Acid level(B-cell lymphoma 2 and Bcl-xL),and increased endothelial junction proteins(VE-cadherin and occludin).Reversely,mTOR inhibitor rapamycin and STAT3 inhibitor S3I-201 could raise oxidative stress and mitochondria-dependent apoptosis even with HGF treatment in LPS-induced endothelial cells.Similarly,mTORC1 as well as mTORC2 have the same protective effects in mitochondria damage and apoptosis.Inin vivo experiments of ALI mouse,HGF also increased mitochondria structural integrity via the mTOR/STAT3 pathway.Conclusion:In all,these reveal that mTOR/STAT3 signaling mediates the HGF suppression effects to oxidative level,mitochondria-dependent apoptosis,and endothelial junction protein in ARDS,contributing to the pulmonary endothelial survival and barrier integrity.

Changes in the permeability of blood brain barrier and endothelial cell damage after cerebral ischemia

OBJECTIVE： To investigate the effect of endothelial cells on the permeability of blood brain barrier （BBB） after brain injury and its effect mechanism. DATA SOURCES： We searched for the articles of permeability of BBB and endothelial cell injury after brain is- chemia, which were published between January 1982 and December 2005, with the key words of ＂cerebral ischemia damage,blood brain barrier （ BBB）,permeability,effect of endothelial cell （EC） and its variation mechanism＂in English. STUDY SELECTION： The materials were primarily selected. The articles related to the changes in the permeability of BBB and the effect of endothelial cells as well as the change mechanism after cerebral ischemia damage were chosen. Repetitive studies or review articles were excluded. DATA EXTRACTION： Totally 55 related articles were collected, and 35 were excluded due to repetitive or review articles, finally 20 articles were involved. DATA SYNTHESIS： The content or viewpoints of involved literatures were analyzed. Cerebral ischemia had damage for endothelial cells, such as the inflow of a lot of Ca2^＋, the production of nitrogen monoxide and oxygen free radical, and aggravated destruction of BBB. After acceptors of inflammatory mediators on cerebrovascular endothelial cell membrane, such as histamine, bradykinin , 5-hydroxytryptamine and so on are activated, endothelial cells shrink and the permeability of BBB increases. Its mechanism involves in the inflow of extracellular Ca^＋2and the release of intracellular Ca^2＋ in the cells. Glycocalyx molecule on the surface of endothelial cell, having structural polytropy, is the determinative factor of the permeability of BBB. VEGF, intensively increasing the vasopermeability and mainly effecting on postcapillary vein and veinlet, is the strongest known blood vessel permeation reagent. Its chronic overexpression in the brain can lead the destruction of BBB. CONCLUSION： The injury of endothelial cell participants in the pathological mechanism of BBB destruction after cerebral ischemla.

Damage of vascular endothelial barrier induced by explosive blast and its clinical significance

In recent years, injuries induced by explosive blast have got more and more attention owing to weapon development and frequent terrorist activities. Tear, bleeding and edema of tissues and organs are the main manifestations of blast shock wave damage. Vascular endothelial barrier is the main defense of tissues and organs＇ integrity. This article aims to discuss possible mechanisms of endothelial barrier damage induced by explosive blast and main manifestations of blood brain barrier, blood-air barrier, and intestinal vascular barrier impairments. In addition, the main regulatory factors of vascular permeability are also summarized so as to provide theoretical basis for prevention and cure of vascular endothelial barrier damaue resultinu from exolosive blast.

Uptake of citrate-coated iron oxide nanoparticles into atherosclerotic lesions in mice occurs via accelerated transcytosis through plaque endothelial cells

Very small superparamagnetic iron oxide nanoparticles （VSOPs） rapidly accumulate in atherosclerotic lesions, thereby enabling plaque visualization by magnetic resonance imaging （MRI）. This study was performed to identify the uptake mechanisms of VSOPs into atherosclerotic plaques. Low-density lipoprotein receptor-deficient （LDLR^-/-） mice with advanced atherosclerosis were analyzed using MRI and transmission electron microscopy （TEM） at various time points after intravenous administration of VSOPs. Post-mortem MRI detected VSOP labeling of atherosclerotic plaques 10 min after injection, and the signal increased over the first 3 h. TEM revealed that the intensive plaque labeling was mediated by accelerated transcytosis of VSOPs through endothelial cells overlaying atherosclerotic lesions. Experiments with endocytosis inhibitors and small interfering RNA （siRNA） revealed a dynamin-dependent mechanism involving both clathrin- and caveolin-mediated processes. In cell culture experiments, endothelial VSOP uptake was enhanced under proatherogenic flow and TNFα stimulation, conditions that are both present in plaque areas. Our study demonstrates that VSOPs enable non-invasive MRI assessment of accelerated endothelial transcytosis, an important pathomechanism in atherosclerotic plaque formation.