Interplay of cysteinyl leukotrienes and TGF-β in the activation of hepatic stellate cells from Schistosoma mansoni granulomas.
Hepatic stellate cells (HSCs) have a critical role in liver physiology, and in the pathogenesis of liver inflammation and fibrosis. Here, we investigated the interplay between leukotrienes (LT) and TGF-β in the activation mechanisms of HSCs from schistosomal granulomas (GR-HSCs). First, we demonstrated that GR-HSCs express 5-lipoxygenase (5-LO), as detected by immunolocalization in whole cells and confirmed in cell lysates through western blotting and by mRNA expression through RT-PCR. Moreover, mRNA expression of 5-LO activating protein (FLAP) and LTC(4)-synthase was also documented, indicating that GR-HSCs have the molecular machinery required for LT synthesis. Morphological analysis of osmium and Oil-Red O-stained HSC revealed large numbers of small lipid droplets (also known as lipid bodies). We observed co-localization of lipid droplet protein marker (ADRP) and 5-LO by immunofluorescence microscopy. We demonstrated that GR-HSCs were able to spontaneously release cysteinyl-LTs (CysLTs), but not LTB(4,) into culture supernatants. CysLT production was highly enhanced after TGF-β-stimulation. Moreover, the 5-LO inhibitor zileuton and 5-LO gene deletion were able to inhibit the TGF-β-stimulated proliferation of GR-HSCs, suggesting a role for LTs in HSC activation. Here, we extend the immunoregulatory function of HSC by demonstrating that HSC from liver granulomas of schistosome-infected mouse are able to release Cys-LTs in a TGF-β-regulated manner, potentially impacting pathogenesis and liver fibrosis in schistosomiasis.
Paiva
Ligia A
LA
Laboratory of Immunopharmacology, Institute Oswaldo Cruz, Manguinhos, Rio de Janeiro, RJ, Brazil.
Maya-Monteiro
Clarissa M
CM
Bandeira-Melo
Christianne
C
Silva
Patricia M R
PM
El-Cheikh
Marcia C
MC
Teodoro
Anderson J
AJ
Borojevic
Radovan
R
Perez
Sandra A C
SA
Bozza
Patricia T
PT
D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D017931:DNA Primers; D006099:Granuloma / Q000469:parasitology*; D015289:Leukotrienes / Q000096:biosynthesis / Q000378:metabolism*; D008099:Liver / Q000469:parasitology / Q000473:pathology*; D051379:Mice; D008856:Microscopy, Fluorescence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012550:Schistosoma mansoni / Q000302:isolation & purification / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D017931:DNA Primers; D015289:Leukotrienes; D016212:Transforming Growth Factor beta; D001094:Arachidonate 5-Lipoxygenase