Open AccessHypoxia‐induced activin A diminishes endothelial cell vasculogenic activity
Author(s) -
MerfeldClauss Stephanie,
Lu Hongyan,
Wu Xue,
March Keith L.,
Traktuev Dmitry O.
Publication year - 2018
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/jcmm.13306
Subject(s) - hypoxia (environmental) , microbiology and biotechnology , chemistry , endothelial stem cell , medicine , endocrinology , biology , biochemistry , oxygen , organic chemistry , in vitro
Acute ischaemia causes a significant loss of blood vessels leading to deterioration of organ function. Multiple ischaemic conditions are associated with up‐regulation of activin A, but its effect on endothelial cells ( EC ) in the context of hypoxia is understudied. This study evaluated the role of activin A in vasculogenesis in hypoxia. An in vitro vasculogenesis model, in which EC were cocultured with adipose stromal cells ( ASC ), was used. Incubation of cocultures at 0.5% oxygen led to decrease in EC survival and vessel density. Hypoxia up‐regulated inhibin B A (monomer of activin A) mRNA by 4.5‐fold and activin A accumulation in EC ‐conditioned media by 10‐fold, but down‐regulated activin A inhibitor follistatin by twofold. Inhibin B A expression was also increased in human EC injected into ischaemic mouse muscles. Activin A secretion was positively modulated by hypoxia mimetics dimethyloxalylglycine and desferrioxamine. Silencing HIF 1α or HIF 2α expression decreased activin A secretion in EC exposed to hypoxia. Introduction of activin A to cocultures decreased EC number and vascular density by 40%; conversely, blockade of activin A expression in EC or its activity improved vasculogenesis in hypoxia. Activin A affected EC survival directly and by modulating ASC paracrine activity leading to diminished ability of the ASC secretome to support EC survival and vasculogenesis. In conclusion, hypoxia up‐regulates EC secretion of activin A, which, by affecting both EC and adjacent mesenchymal cells, creates a micro‐environment unfavourable for vasculogenesis. This finding suggests that blockade of activin A signalling in ischaemic tissue may improve preservation of the affected tissue.