scholarly journals Endothelial Protease Activated Receptor 1 (PAR1) Signalling Is Required for Lymphocyte Transmigration across Brain Microvascular Endothelial Cells

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2723
Author(s):  
Silvia Dragoni ◽  
Anna Papageorgiou ◽  
Caroline Araiz ◽  
John Greenwood ◽  
Patric Turowski
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Adherens Junction ◽  
Signalling Pathways ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Blocking Antibodies ◽  
Amp Activated Protein Kinase ◽  
Endothelial Nitric Oxide

Lymphocyte transendothelial migration (TEM) relies on ICAM-1 engagement on the luminal surface of the endothelial cells (ECs). In blood–brain barrier (BBB) ECs, ICAM-1 triggers TEM signalling, including through JNK MAP kinase and AMP-activated protein kinase (AMPK), which lead to the phosphorylation and internalisation of the adherens junction protein VE-cadherin. In addition to ICAM-1, G protein-coupled receptors (GPCRs) are also required for lymphocytes TEM across BBB ECs. Here, we investigated the role of protease activated GPCRs (PARs) and found a specific role for PAR1 in support of lymphocyte TEM across BBB ECs in vitro. PAR1 requirement for TEM was confirmed using protease inhibitors, specific small molecule and peptide antagonists, function blocking antibodies and siRNA-mediated knockdown. In BBB ECs, PAR1 stimulation led to activation of signalling pathways essential to TEM; notably involving JNK and endothelial nitric oxide synthase (eNOS), with the latter downstream of AMPK. In turn, nitric oxide production through eNOS was essential for TEM by modulating VE-cadherin on Y731. Collectively, our data showed that non-canonical PAR1 activation by a lymphocyte-released serine protease is required for lymphocyte TEM across the BBB in vitro, and that this feeds into previously established ICAM-1-mediated endothelial TEM signalling pathways.

scholarly journals Adherens junction protein, p120 catenin, represses transcriptional activity of endothelial cells

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Hazel Lum ◽  
Feng Cheng ◽  
James J. O'Donnell ◽  
Hee‐jeong Im ◽  
Oksana Holian
Keyword(s):  
Endothelial Cells ◽  
Transcriptional Activity ◽  
Adherens Junction ◽  
P120 Catenin ◽  
Adherens Junction Protein ◽  
Junction Protein

scholarly journals Endothelial Nitric Oxide Synthase Expression Is Progressively Increased in Primary Cerebral Microvascular Endothelial Cells During Hyperbaric Oxygen Exposure

2009 ◽  
Vol 2 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Xiongfei Xu ◽  
Zhongzhuang Wang ◽  
Quan Li ◽  
Xiang Xiao ◽  
Qinglin Lian ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Hyperbaric Oxygen ◽  
Endothelial Nitric Oxide Synthase ◽  
Microvascular Endothelial Cells ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Enos Protein

Exposure to hyperbaric oxygen (HBO) can lead to seizures. Many studies have demonstrated that there exist a very close relationship between the alteration of cerebral blood flow (CBF) and the onset of seizures. Nitric oxide (NO) may play a key role in the change of CBF during exposure, and modulation of endothelial nitric oxide synthase (eNOS)-derived NO by HBO is responsible for early vasoconstriction, whereas late HBO-induced vasodilation depends upon a large amount of NO from both eNOS and neuronal nitric oxide synthase (nNOS). To investigate the effect of HBO on the activity and expression of eNOS in cerebral microvascular endothelial cells (CMEC) in vitro, primarily cultured CMEC from neonatal rats were exposed to oxygen at 500 kPa [5 atmosphere absolute (ATA)] for 10, 20, 30, 60 and 120 minutes (min), then eNOS activity, protein and mRNA contents in cells were detected. Our results showed that immediately after exposure, 30, 60 and 120 min HBO exposures did not alter NOS activity. When detected no matter immediately or six hours (h) after exposure, these exposures also did not alter eNOS protein and mRNA levels. However, when detected 24 h after exposure, 30, 60 and 120 min exposures upregulated eNOS protein content by 39%, 60% and 40% respectively. 10 and 20 min exposures upregulated eNOS mRNA content by about 15%, while 30, 60 and 120 min exposures upregulated it by about 20–30%. The increased eNOS protein and mRNA contents at 24 h after exposure may reflect new protein synthesis for eNOS. Our studies showed that with the exposing protocols we used, HBO did induce eNOS expression increase in CMEC. However, compared with the decrease of CBF in vivo, which occurred in a relative short time after rat was exposed to HBO above 4 ATA, the responses of eNOS in CMEC in vitro were a little slow. Thus we considered that for the vasodilation in the late period of HBO exposure before seizure, the effect of NO produced by eNOS was limited.

116. Contribution of claudin-11 to the inter-Sertoli cell tight junction, in vitro

2005 ◽  
Vol 17 (9) ◽  
pp. 72
Author(s):  
M. J. McCabe ◽  
P. G. Stanton
Keyword(s):  
Tight Junction ◽  
Mrna Expression ◽  
Sertoli Cell ◽  
Adhesion Molecule ◽  
Sertoli Cells ◽  
Adherens Junction ◽  
Adherens Junction Protein ◽  
Junction Protein

The inter-Sertoli cell tight junction (TJ) forms the blood testis barrier (BTB) between Sertoli cells and is composed of three major transmembrane proteins: claudin-11, occludin and junctional adhesion molecule. Formation of the BTB occurs during puberty associating with an increase in circulating gonadotrophins. Claudin-11 and occludin are hormonally regulated in vitro although their importance to the function of the TJ is unknown. The aim of this study was to investigate the contribution of claudin-11 to the inter-Sertoli cell TJ in vitro by blocking gene expression using RNA interference. Two claudin-11-specific siRNA fragments were designed for this purpose. Sertoli cells in primary culture formed stable TJs within 5 days as measured by transepithelial electrical resistance (TER). The addition of siRNA for 2 days resulted in a significant (P < 0.01) 55% (mean, SD, n = 4 cultures) decrease in TER along with a major reduction in claudin-11 localisation to the TJ as assessed by immunocytochemistry. The specificity of the siRNA was shown by the presence of extensive immunostaining of occludin and of the adherens junction protein β-catenin in the same treatments. Similarly, claudin-11 mRNA expression significantly (P < 0.01) decreased by 71% (mean, SD, n = 3 cultures) in response to both claudin-11 siRNA fragments. Occludin mRNA expression was not affected. It is concluded that claudin-11 contributes at least 55% to the function of the rat Sertoli cell TJ in vitro. It is hypothesised that the remaining 45% of TJ function can be attributed to other integral proteins, such as occludin and junctional adhesion molecule. It is expected that claudin-11 and other TJ proteins play a pivotal role in the function of the BTB in vivo with potential implications in fertility and contraception.

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