Mechanisms of endothelial cell dysfunction in cystic fibrosis

Although cystic fibrosis (CF) patients exhibit signs of endothelial perturbation, the functions of the cystic fibrosis conductance regulator (CFTR) in vascular endothelial cells (EC) are poorly defined. We sought to uncover biological activities of endothelial CFTR, relevant for vascular homeostasis and inflammation. We examined cells from human umbilical cords (HUVEC) and pulmonary artery isolated from non-cystic fibrosis (PAEC) and CF human lungs (CF-PAEC), under static conditions or physiological shear. CFTR activity, clearly detected in HUVEC and PAEC, was markedly reduced in CF-PAEC. CFTR blockade increased endothelial permeability to macromolecules and reduced trans‑endothelial electrical resistance (TEER). Consistent with this, CF-PAEC displayed lower TEER compared to PAEC. Under shear, CFTR blockade reduced VE-cadherin and p120 catenin membrane expression and triggered the formation of paxillin- and vinculin-enriched membrane blebs that evolved in shrinking of the cell body and disruption of cell-cell contacts. These changes were accompanied by enhanced release of microvesicles, which displayed reduced capability to stimulate proliferation in recipient EC. CFTR blockade also suppressed insulin-induced NO generation by EC, likely by inhibiting eNOS and AKT phosphorylation, whereas it enhanced IL-8 release. Remarkably, phosphodiesterase inhibitors in combination with a β2 adrenergic receptor agonist corrected functional and morphological changes triggered by CFTR dysfunction in EC. Our results uncover regulatory functions of CFTR in EC, suggesting a physiological role of CFTR in the maintenance EC homeostasis and its involvement in pathogenetic aspects of CF. Moreover, our findings open avenues for novel pharmacology to control endothelial dysfunction and its consequences in CF

Src family kinases mediate neutrophil adhesion to adherent platelets

Polymorphonuclear leukocyte (PMN)–platelet interactions at sites of vascular damage contribute to local and systemic inflammation. We sought to determine the role of “outside-in” signaling by Src-family tyrosine kinases (SFKs) in the regulation of αMβ2-integrin–dependent PMN recruitment by activated platelets under (patho)physiologic conditions. Activation-dependent epitopes in β2 integrin were exposed at the contact sites between PMNs and platelets and were abolished by SFK inhibitors. PMNs from αMβ2(−/−), hck(−/−)fgr(−/−), and hck(−/−)fgr(−/−)lyn(−/−) mice had an impaired capacity to adhere with activated platelets in suspension. Phosphorylation of Pyk2 accompanied PMN adhesion to platelets and was blocked by inhibition as well as by genetic deletion of αMβ2 integrin and SFKs. A Pyk2 inhibitor reduced platelet-PMN adhesion, indicating that Pyk2 may be a downstream effector of SFKs. Analysis of PMN-platelet interactions under flow revealed that SFK signaling was required for αMβ2-mediated shear-resistant adhesion of PMNs to adherent platelets, but was dispensable for P-selectin–PSGL-1–mediated recruitment and rolling. Finally, SFK activity was required to support PMN accumulation along adherent platelets at the site of vascular injury, in vivo. These results definitely establish a role for SFKs in PMN recruitment by activated platelets and suggest novel targets to disrupt the pathophysiologic consequences of platelet-leukocyte interactions in vascular disease

The natural phosphoinositide derivative glycerophosphoinositol inhibits the lipopolysaccharide-induced inflammatory and thrombotic responses

Inflammatory responses are elicited through lipid products of phospholipase A(2) activity that acts on the membrane phospholipids, including the phosphoinositides, to form the proinflammatory arachidonic acid and, in parallel, the glycerophosphoinositols. Here, we investigate the role of the glycerophosphoinositol in the inflammatory response. We show that it is part of a negative feedback loop that limits proinflammatory and prothrombotic responses in human monocytes stimulated with lipopolysaccharide. This inhibition is exerted both on the signaling cascade initiated by the lipopolysaccharide with the glycerophosphoinositol-dependent decrease in IB kinase /, p38, JNK, and Erk1/2 kinase phosphorylation and at the nuclear level with decreased NF-B translocation and binding to inflammatory gene promoters. In a model of endotoxemia in the mouse, treatment with glycerophosphoinositol reduced TNF- synthesis, which supports the concept that glycerophosphoinositol inhibits the de novo synthesis of proinflammatory and prothrombotic compounds and might thus have a role as an endogenous mediator in the resolution of inflammation. As indicated, this effect of glycerophosphoinositol can also be exploited in the treatment of manifestations of severe inflammation by exogenous administration of the compound

Reduced mortality risk by a polyphenol-rich diet: An analysis from the Moli-sani study

Objectives: The effect of the polyphenol content of the human diet on mortality risk is not yet fully understood. The aim of this study was to evaluate the association of a polyphenol-rich diet with mortality rate and a possible mediation effect by inflammation, in what we believe to be a novel, holistic approach. Methods: We analyzed 21 302 participants (10 980 women and 10 322 men, aged 6535 y) from the Moli-sani cohort. The participants were followed up for a median of 8.3 y. The European Prospective Investigation into Cancer and Nutrition food frequency questionnaire (FFQ) was used for dietary assessment. Flavonol, flavone, flavanone, flavanol, anthocyanin, isoflavone, and lignan intakes were calculated using European Food Information Resource\u2014Bioactive Substances in Food Information Systems and the polyphenol antioxidant content (PAC)-score was constructed to assess the total content of these nutrients in the diet. Results: Participants included in the highest quintile of intake of various polyphenol classes and subclasses presented a significant lower all-cause mortality risk compared with those in the lowest group of consumption (hazard ratio [HR] < 1; P < 0.05). Cox regression analyses adjusted for potential confounders indicated that participants in higher quintiles of PAC-score had lower all-cause mortality risk (HR <1; P < 0.05). When cause-specific mortality rates were considered, similar effects were observed for cardiocerebrovascular and cancer mortality (HR <1; P < 0.05). Conclusions: The polyphenol content of the diet was associated with reduced mortality risk in a Mediterranean population, possibly through an antiinflammatory mechanism