Danesh, M. | bioRxiv Science

bioRxiv2022

Soluble VE-cadherin disrupts endothelial barrier function via VE-PTP/RhoA signalling

AimIncreased levels of soluble Vascular endothelial (VE)-cadherin fragments (sVE-cadherin) have previously been linked with inflammation-induced loss of endothelial barrier function. We tested whether sVE-cadherin is critically involved in the onset of endothelial barrier dysfunction. Methods and ResultsApplication of recombinant human sVE-cadherin (extracellular domains EC1-5) on human microvascular endothelial cells in vitro and in a rat model in vivo induced loss of endothelial barrier function and reduced microcirculatory flow. sVE-cadherinEC1-5 led to decreased localization of VE-cadherin at cell borders. Additionally, sVE-cadherinEC1-5 perturbed VE-protein tyrosine phosphatase (VE-PTP)/VE-cadherin interaction. VE-PTP inhibitor AKB9778 blunted all sVE-cadherinEC1-5-induced effects in vitro and in vivo. Downstream effects involve VE-PTP-dependent RhoA activation which was attenuated by AKB9778. Rho-kinase inhibitor Y27632 blocked sVE-cadherinEC1-5-induced loss of endothelial barrier function. ConclusionsVE-cadherin disrupts endothelial barrier function by dismantling the VE-cadherin complex at cell borders via VE-PTP-dependent RhoA activation. This uncovers a novel pathophysiological role of sVE-cadherin in the context of endothelial barrier dysfunction in inflammation.

physiology↗

bioRxiv2018

Evaluating analgesic efficacy and administration route following craniotomy in mice using the grimace scale

Most research laboratories abide by guidelines and mandates set by their research institution regarding the administration of analgesics to control pain during the postoperative period. Unfortunately, measuring pain originating from the head is difficult, making adequate decisions regarding pain control following stereotaxic surgery problematic. In addition, most postsurgical analgesia protocols require multiple injections over several days, which may cause stress and distress during a critical recovery period. Here we sought to 1) assess the degree of postoperative pain following craniotomy in mice, 2) compare the efficacy of three common rodent analgesics (carprofen, meloxicam and buprenorphine) for reducing this pain and 3) determine whether the route of administration (injected or self-administered through the water supply) influenced pain relief post-craniotomy. Using the mouse grimace scale (MGS), we found that injectable analgesics were significantly more effective at relieving post-craniotomy pain, however, both routes of administration decreased pain scores in the first 24 h post-surgery. Specifically, buprenorphine administered independently of administration route was the most effective at reducing MGS scores, however, female mice showed greater sensitivity to carprofen when administered through the water supply. Although it is necessary to provide laboratory animals with analgesics after an invasive procedure, there remains a gap in the literature regarding the degree of craniotomy-related pain in rodents and the efficacy of alternative routes of administration. Our study highlights the limitations of administering drugs through the water supply, even at doses that are considered to be higher than those currently recommended by most research institutions for treating pain of mild to moderate severity.

neuroscience↗