TGF-β1 induces transendothelial migration of the pathogenic fungus Sporothrix schenckii by a paracellular route involving extracellular matrix proteins

Abstract

Sporotrichosis, a mycosis caused by Sporothrix schenckii, is characterized by lymphocutaneous lesions. In immunocompromised hosts, this fungus may invade the bloodstream and disseminate to other tissues, such as lung and bone. Our group previously showed that S. schenckii yeasts adhere to endothelial monolayers and that this interaction is modulated by cytokines. Using 3.0 mm-pore culture inserts, the present work shows that transforming growth factor (TGF)-b1 led to a 80±26 % increase in fungal migration across endothelial monolayers and inhibited fungus internalization by 55±23.5 %, when compared to untreated cells. The major surface endothelial molecules recognized by S. schenckii were not modulated by TGF-b1. These data suggested that a paracellular route is preferentially used by S. schenckii during the transmigration of cultured endothelial cells. It was further observed that TGF-b1 increased the subendothelial matrix exposure and that anti-fibronectin (anti-FN) and anti-laminin (anti-LM) antibodies abolished the increase in S. schenckii association with endothelial monolayers induced by TGF-b1. These antibodies also inhibited (38.2±4.29 % and 50.8±17.3 %, respectively) the adhesion of S. schenckii to freshly prepared native endothelial matrices. Furthermore, transendothelial migration of S. schenckii was blocked by anti-FN and anti-LM antibodies. These data indicate that TGF-b1-induced S. schenckii adhesion to endothelial monolayers results from the increased exposure of the subendothelial extracellular matrix and that this event may contribute to the enhancement of transendothelial migration.

Passive immunization with monoclonal antibody against a 70‐kDa putative adhesin of Sporothrix schenckii induces protection in murine sporotrichosis

“…Pretreatment of endothelial ECM with anti-LM and anti-FN significantly inhibited S. schenckii adhesion by 23.4 and 35.6%, respectively, as described by others [15,16]. However, data concerning the adhesins of S. schenckii to ECM proteins are still lacking.…”

“…It has been previously shown that during the interaction of S. schenckii yeast cells with endothelial cell monolayers, a significant amount of yeast is found at the intercellular junctions. Furthermore, anti-LM and anti-FN antibodies can inhibit the interaction and transmigration of this fungus through endothelial monolayers [16,32]. We have demonstrated here that gp70 molecule is a putative adhesin for FN and LM by affinity blotting analysis.…”

“…Subendothelial ECM was obtained from endothelial monolayers as previously described [16]. The residual matrix fraction saturated overnight at 41C with casein (1 mg/mL) was used in the S. schenckii adhesion assays.…”

Sporothrix schenckii and Sporotrichosis

“…Both processes facilitate fungus bloodstream penetration and consequent hematogenous dissemination (69). Transendothelium migration occurs through a paracellular route involving extracellular matrix proteins, in a process mediated by transforming growth factor ␤1 (TGF-␤1) (70). Although the endothelial proteins responsible for this interaction have been characterized, fungal proteins needed for recognition of and adhesion to these cells are unknown, and their part in fungal virulence requires clarification.…”

Group B Streptococcus induces tyrosine phosphorylation of annexin V and glutathione S-transferase in human umbilical vein endothelial cells

“…As soon as GBS begins to establish physical contact with the host cell surface, we observed the formation of stress fibers in HUVECs. Such morphological alterations on the cytoskeleton in vitro alters endothelial permeability, exposing the subendothelial matrix, which is explored by GBS, as already described for other pathogens (25). It is a point that deserves to be further investigated.…”