Desert Hedgehog-driven endothelium integrity is enhanced by Gas1 but negatively regulated by Cdon

Abstract

Evidences accumulated within the past decades, identified Hedgehog (Hh) signaling as a new regulator of micro-vessel integrity. More specifically, we recently identified Desert Hedgehog (Dhh) as a downstream effector of Klf2 in endothelial cells (ECs). Objective: The purpose of this study is to investigate whether Hh co-receptors Gas1 and Cdon may be used as therapeutic targets to modulate Dhh signaling in ECs. Methods and results: We demonstrated that both Gas1 and Cdon are expressed in adult ECs and relied on either siRNAs or EC specific conditional KO mice to investigate their role. We found that Gas1 deficiency mainly photocopies Dhh deficiency especially by inducing VCAM-1 and ICAM-1 overexpression while Cdon deficiency has opposite effects by promoting endothelial junction integrity. At a molecular level, Cdon prevents Dhh binding to Ptch1 and thus acts a decoy receptor for Dhh, while Gas1 promotes Dhh binding to Smo and as a result potentiates Dhh effects. Since Cdon is overexpressed in ECs treated by inflammatory cytokines including TNFα and Il1β, we then tested whether Cdon inhibition would promote endothelium integrity in acute inflammatory conditions and found that both fibrinogen and IgG extravasation were decreased in association with an increased Cdh5 expression in the brain cortex of EC specific Cdon KO mice administered locally with Il1β.

Temporal transcriptome analysis of the endothelial response to tumour necrosis factor

“…We identified a panel of 210 gene transcripts that were at lower levels following TNFstimulation. Whilst studies of the TNF response tend to focus on genes whose expression in increased in response to stimulation, several of those we identified as down regulated had been previously reported as such, e.g., NOS3, the mRNA stability of which is inhibited by TNF (Yan et al, 2008), DHH, which prevents EC activation (Chapouly et al, 2020), and RGS4, which regulates the secretion of VWF (Patella and Cutler, 2020). However, many had not been previously reported in this context, e.g., CNR1, SLC7A8 and CLEC14A, which were amongst the most down regulated by TNF.…”

Increased endothelium activation and leakage do not promote diastolic dysfunction in mice fed with a high fat diet and treated with L-NAME

“…To induce Cre, tamoxifen is injected IP 1 mg/mL 5 consecutive days at 8 weeks of age. Successful and specific activation of the Cre recombinase have been verified before 13 . Animal experiments were performed in accordance with the guidelines from Directive 2010/63/EU of the European Parliament on the protection of animals used for scientific purposes and approved by the local Animal Care and Use Committee of Bordeaux University.…”

“…Altogether these results demonstrate that cardiac small vessel disease only develops in female mice upon the HFD+L-NAME regimen. In order to investigate whether or not cardiac small vessel disease may participate in the development of diastolic dysfunction in OVX female mice, we used a mouse model in which we have previously shown endothelial integrity is preserved upon stress 13 i.e. endothelial specific Cdon deficient mice.…”

“…C57BL/6J mice were obtained from Charles River laboratories and bred in our animal facility. Cdon floxed (Cdon tm1c(EUCOMM)Hmgu ) (Cdon Flox ) 13 mice were generated at the Institut Clinique de la Souris through the International Mouse Phenotyping Consortium from a vector generated by the European conditional mice mutagenesis program, EUCOMM. Cdon floxed mice were generated under a C57BL/6N background and backcrossed at least 6 times with C57BL/6J mice before they were used in any experiment.…”

Plasma Proteomic Profiling in Hypertrophic Cardiomyopathy Patients Before and After Surgical Myectomy Reveals Post-Procedural Reduction in Systemic Inflammation

“…In Figure 2B, Box Whisker plots of the Pre and Post samples illustrate the difference in SOMAscan expression levels for six representative targets linked to myectomy: POSTN, MMP12, CDON, NAMPT, HAMP, and LTA4H are included. Several of the proteins impacted by myectomy (POSTN, MMP12, CDON, NAMPT, HAMP, LTA4H) have been previously reported to be altered in cardiovascular disease, cardiomyopathy or vascular disease with effects mediated through inflammatory mechanisms [5][6][7][8][9][10][11][12][13].…”