Modifications to the composition of the hyphal outer layer of Aspergillus fumigatus modulates HUVEC proteins related to inflammatory and stress responses.
Aspergillus fumigatus, the main etiologic agent causing invasive aspergillosis, can induce an inflammatory response and a prothrombotic phenotype upon contact with human umbilical vein endothelial cells (HUVECs). However, the fungal molecules involved in this endothelial response remain unknown. A. fumigatus hyphae produce an extracellular matrix composed of galactomannan, galactosaminogalactan and α-(1,3)-glucan. In this study, we investigated the consequences of UGM1 gene deletion in A. fumigatus, which produces a mutant with increased galactosaminogalactan production. The ∆ugm1 mutant exhibited an HUVEC-hyperadhesive phenotype and induced increased endothelial TNF-α secretion and tissue factor mRNA overexpression in this "semi-professional" immune host cell. Using a shotgun proteomics approach, we show that the A. fumigatus ∆ugm1 strain can modulate the levels of proteins in important endothelial pathways related to the inflammatory response mediated by TNF-α and to stress response pathways. Furthermore, a purified galactosaminogalactan fraction was also able to induce TNF-α secretion and the coincident HUVEC pathways regulated by the ∆ugm1 mutant, which overexpresses this component, as demonstrated by fluorescence microscopy. This work contributes new data regarding endothelial mechanisms in response to A. fumigatus infection.



Invasive aspergillosis is the main opportunistic fungal infection described in neutropenic hematologic patients. One important clinical aspect of this invasive fungal infection is vascular thrombosis, which could be related, at least in part, to the activation of endothelial cells, as shown in previous reports from our group. It is known that direct contact between the A. fumigatus hyphal cell wall and the HUVEC cell surface is necessary to induce an endothelial prothrombotic phenotype and secretion of pro-inflammatory cytokines, though the cell surface components of this angioinvasive fungus that trigger this endothelial response are unknown. The present work employs a discovery-driven proteomics approach to reveal the role of one important cell wall polysaccharide of A. fumigatus, galactosaminogalactan, in the HUVEC interaction and the consequent mechanisms of endothelial activation. This is the first report of the overall panel of proteins related to the HUVEC response to a specific and purified cell wall component of the angioinvasive fungus A. fumigatus.
Laboratory of Cellular Mycology and Proteomics, Universidade do Estado do Rio de Janeiro, Campus Maracanã, Pavilhão Haroldo Lisboa da Cunha sl 501D, CEP: 20550-013, Rio de Janeiro, RJ, Brazil.
Gabriela Westerlund Peixoto
GW
Neves
Laboratory of Cellular Mycology and Proteomics, Universidade do Estado do Rio de Janeiro, Campus Maracanã, Pavilhão Haroldo Lisboa da Cunha sl 501D, CEP: 20550-013, Rio de Janeiro, RJ, Brazil.
Nathália de Andrade
NA
Curty
Laboratory of Cellular Mycology and Proteomics, Universidade do Estado do Rio de Janeiro, Campus Maracanã, Pavilhão Haroldo Lisboa da Cunha sl 501D, CEP: 20550-013, Rio de Janeiro, RJ, Brazil.
Paula Helena
PH
Kubitschek-Barreira
Unité des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724, Paris Cedex 15, France.
Thierry
T
Fontaine
MS Applications Research and Development Laboratory, Waters Corporation, São Paulo, Brazil.
Gustavo Henrique Martins Ferreira
GH
Souza
Laboratory of Cellular Mycology and Proteomics, Universidade do Estado do Rio de Janeiro, Campus Maracanã, Pavilhão Haroldo Lisboa da Cunha sl 501D, CEP: 20550-013, Rio de Janeiro, RJ, Brazil.
Marcel Lyra
ML
Cunha
Universidade de São Paulo, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Av. do Cafe S/N, Monte Alegre, CEP:14040-903, Ribeirao Preto, SP, Brazil.
Gustavo H
GH
Goldman
Unité des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724, Paris Cedex 15, France.
Anne
A
Beauvais
Unité des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724, Paris Cedex 15, France.
Jean-Paul
JP
Latgé
Laboratory of Cellular Mycology and Proteomics, Universidade do Estado do Rio de Janeiro, Campus Maracanã, Pavilhão Haroldo Lisboa da Cunha sl 501D, CEP: 20550-013, Rio de Janeiro, RJ, Brazil. Electronic address: leila@uerj.br.
Leila M
LM
Lopes-Bezerra
D001232:Aspergillus fumigatus / Q000737:chemistry* / Q000235:genetics; D042783:Endothelial Cells / Q000378:metabolism; D005656:Fungal Proteins / Q000502:physiology; D017353:Gene Deletion; D054884:Host-Pathogen Interactions; D061307:Human Umbilical Vein Endothelial Cells / Q000737:chemistry* / Q000382:microbiology*; D006801:Humans; D025301:Hyphae / Q000737:chemistry*; D007249:Inflammation; D011134:Polysaccharides / Q000096:biosynthesis; D013312:Stress, Physiological; D013927:Thrombosis / Q000209:etiology / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D005656:Fungal Proteins; D011134:Polysaccharides; D014409:Tumor Necrosis Factor-alpha; C062157:galactosaminogalactan
Aspergillus fumigatus; Galactosaminogalactan; HUVEC; Inflammatory response; Δugm1 mutant