Endothelial Regulator of Calcineurin 1 Promotes Barrier Integrity and Modulates Histamine-Induced Barrier Dysfunction in Anaphylaxis

Abstract

Anaphylaxis, the most serious and life-threatening allergic reaction, produces the release of inflammatory mediators by mast cells and basophils. Regulator of calcineurin 1 (Rcan1) is a negative regulator of mast-cell degranulation. The action of mediators leads to vasodilation and an increase in vascular permeability, causing great loss of intravascular volume in a short time. Nevertheless, the molecular basis remains unexplored on the vascular level. We investigated Rcan1 expression induced by histamine, platelet-activating factor (PAF), and epinephrine in primary human vein (HV)-/artery (HA)-derived endothelial cells (ECs) and human dermal microvascular ECs (HMVEC-D). Vascular permeability was analyzed in vitro in human ECs with forced Rcan1 expression using Transwell migration assays and in vivo using Rcan1 knockout mice. Histamine, but neither PAF nor epinephrine, induced Rcan1-4 mRNA and protein expression in primary HV-ECs, HA-ECs, and HMVEC-D through histamine receptor 1 (H1R). These effects were prevented by pharmacological inhibition of calcineurin with cyclosporine A. Moreover, intravenous histamine administration increased Rcan1 expression in lung tissues of mice undergoing experimental anaphylaxis. Functional in vitro assays showed that overexpression of Rcan1 promotes barrier integrity, suggesting a role played by this molecule in vascular permeability. Consistent with these findings, in vivo models of subcutaneous and intravenous histamine-mediated fluid extravasation showed increased response in skin, aorta, and lungs of Rcan1-deficient mice compared with wild-type animals. These findings reveal that endothelial Rcan1 is synthesized in response to histamine through a calcineurin-sensitive pathway and may reduce barrier breakdown, thus contributing to the strengthening of the endothelium and resistance to anaphylaxis. These new insights underscore its potential role as a regulator of sensitivity to anaphylaxis in humans.

The TNF-like weak inducer of the apoptosis/fibroblast growth factor–inducible molecule 14 axis mediates histamine and platelet-activating factor–induced subcutaneous vascular leakage and anaphylactic shock

“…24 Mouse models of systemic vascular permeability and both passive systemic anaphylaxis (PSA) and active systemic anaphylaxis (ASA) were previously described, and sham (control) groups were included in the different experimental models. 25 Anti-dinitrophenyl (DNP) IgE-sensitized mice challenged with PBS were included as controls for PSA. Similarly, a group of mice treated with pertussis toxin diluted in PBS and challenged with bovine serum albumine (BSA) was included as a control for ASA.…”

“…PAF induced severe hypothermia and resulted in spontaneous death of mice within 1 hour. 25,26 PSA-Miles assay mice were challenged with DNP together with 1% Evans blue dye administered intravenously (100 mL). Once mice were intravenously challenged, they were and observed, and pictures were taken 15 minutes later.…”

“…Mouse aortic endothelial cells (MAECs) and mouse lung endothelial cells (MLECs) were isolated from WT or Fn14 2/2 aortas, as previously described, with slight modifications. 25 In vitro vascular permeability assays Endothelial barrier integrity was evaluated by using Transwell 24-well cell culture inserts (TWs), as previously described. 25…”

“…25 In vitro vascular permeability assays Endothelial barrier integrity was evaluated by using Transwell 24-well cell culture inserts (TWs), as previously described. 25…”

Regulator of Calcineurin 1 helps coordinate whole‐body metabolism and thermogenesis

“…Thus, the reduction in inflammatory markers in the gWAT of the KO mice on HFD is likely secondary to the lean phenotype rather than due to suppression of an immune response in the KO. Along these same lines, endothelial cell dysfunction is a prominent feature of diabetes [70], whereas RCAN1 promotes endothelial barrier integrity [71]; thus, loss of Rcan1 in endothelial cells is not likely the driving mechanism behind the lean phenotype in our studies.…”