Secreted Phospholipases A2 in Hereditary Angioedema With C1-Inhibitor Deficiency

Stefania Loffredo; Anne Lise Ferrara; Maria Bova; Francesco Borriello; Chiara Suffritti; Nóra Veszeli; Angelica Petraroli; Maria Rosaria Galdiero; Gilda Varricchi; Francescopaolo Granata; Andrea Zanichelli; Henriette Farkas; Marco Cicardi; Gérard Lambeau; Gianni Marone

doi:10.3389/fimmu.2018.01721

Secreted Phospholipases A₂ in Hereditary Angioedema With C1-Inhibitor Deficiency

Front Immunol. 2018 Jul 23:9:1721. doi: 10.3389/fimmu.2018.01721. eCollection 2018.

Authors

Stefania Loffredo¹, Anne Lise Ferrara¹, Maria Bova¹, Francesco Borriello^{1

2}, Chiara Suffritti³, Nóra Veszeli⁴, Angelica Petraroli¹, Maria Rosaria Galdiero¹, Gilda Varricchi¹, Francescopaolo Granata¹, Andrea Zanichelli³, Henriette Farkas⁴, Marco Cicardi³, Gérard Lambeau⁵, Gianni Marone^{1

6}

Affiliations

¹ Department of Translational Medical Sciences, Center for Basic and Clinical Immunology Research (CISI), University of Naples Federico II, WAO Center of Excellence, Naples, Italy.
² Division of Gastroenterology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States.
³ Department of Biomedical and Clinical Sciences, University of Milan, Luigi Sacco Hospital Milan, Milan, Italy.
⁴ Hungarian Angioedema Center, 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary.
⁵ Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne Sophia Antipolis, France.
⁶ Institute of Experimental Endocrinology and Oncology "G. Salvatore", National Research Council, Naples, Italy.

Abstract

Background: Hereditary angioedema (HAE) caused by deficiency (type I) or dysfunction (type II) of the C1 inhibitor protein (C1-INH-HAE) is a disabling, potentially fatal condition characterized by recurrent episodes of swelling. We have recently found that patients with C1-INH-HAE have increased plasma levels of vascular endothelial growth factors and angiopoietins (Angs), which have been associated with vascular permeability in several diseases. Among these and other factors, blood endothelial cells and vascular permeability can be modulated by extracellular or secreted phospholipases A₂ (sPLA₂s).

Objective: We sought to investigate the enzymatic activity and biological functions of sPLA₂ in patients with C1-INH-HAE.

Methods: sPLA₂s enzymatic activity was evaluated in the plasma from 109 adult patients with C1-INH-HAE and 68 healthy donors in symptom-free period and attacks. Plasma level of group IIA sPLA₂ (hGIIA) protein was measured in selected samples. The effect of C1-INH-HAE plasma on endothelial permeability was examined in vitro using a vascular permeability assay. The role of hGIIA was determined using highly specific sPLA₂ indole inhibitors. The effect of recombinant hGIIA on C1-INH activity was examined in vitro by functional assay.

Results: Plasma sPLA₂ activity and hGIIA levels are increased in symptom-free C1-INH-HAE patients compared with controls. sPLA₂ activity negatively correlates with C1-INH protein level and function. C1-INH-HAE plasma increases endothelial permeability in vitro, and this effect is partially reverted by a specific hGIIA enzymatic inhibitor. Finally, recombinant hGIIA inhibits C1-INH activity in vitro.

Conclusion: sPLA₂ enzymatic activity (likely attributable to hGIIA), which is increased in C1-INH-HAE patients, can promote vascular permeability and impairs C1-INH activity. Our results may pave the way for investigating the functions of sPLA₂s (in particular, hGIIA) in the pathophysiology of C1-INH-HAE and may inform the development of new therapeutic targets.

Keywords: C1 inhibitor deficiency; angiogenesis; angiopoietins; hereditary angioedema; phospholipase A2; vascular endothelial growth factor; vascular permeability.