Resveratrol-induced SIRT1 activation inhibits glycolysis-fueled angiogenesis under rheumatoid arthritis conditions independent of HIF-1α

OBJECTIVE

This study investigated the impacts of SIRT1 activation on rheumatoid arthritis (RA)-related angiogenesis.

METHODS

HUVECs were cultured by different human serum. Intracellular metabolites were quantified by UPLC-MS. Next, HUVECs and rat vascular epithelial cells under different inflammatory conditions were treated by a SIRT1 agonist resveratrol (RSV). Cytokines and biochemical indicators were detected by corresponding kits. Protein and mRNA expression levels were assessed by immunoblotting and PCR methods, respectively. Angiogenesis capabilities were evaluated by migration, wound-healing and tube-formation experiments. To down-regulate certain signals, gene-specific siRNA were applied.

RESULTS

Metabolomics study revealed the accelerated glycolysis in RA serum-treated HUVECs. It led to ATP accumulation, but did not affect GTP levels. RSV inhibited pro-angiogenesis cytokines production and glycolysis in both the cells, and impaired the angiogenesis potentials. These effects were mimicked by an energy metabolism interrupter bikini in lipopolysaccharide (LPS)-primed HUVECs, largely independent of HIF-1α. Both RSV and bikinin can inhibit the activation of the GTP-dependent pathway Rho/ROCK and reduce VEGF production. Abrogation of RhoA signaling reinforced HIF-1α silencing-brought changes in LPS-stimulated HUVECs, and overshadowed the anti-angiogenesis potentials of RSV.

CONCLUSION

Glycolysis provides additional energy to sustain Rho/ROCK activation in RA subjects, which promotes VEGF-driven angiogenesis and can be inhibited by SIRT1 activation.

Imaging of Developing Metaxylem Vessel Elements in Cultured Hypocotyls

An in vitro induction system for xylem vessel formation is a useful tool for visualizing the differentiation of xylem vessel cells. A procedure for inducing xylem vessel cell differentiation in hypocotyls of Arabidopsis thaliana is described here. Metaxylem vessel elements form ectopically in excised hypocotyl tissue following treatment with bikinin. This enables high-resolution imaging of living metaxylem vessel cells. The wide range of resources available for Arabidopsis allows for the visualization of diverse cellular structures, including microtubules and secondary cell walls, in different genetic backgrounds. Use of this system will contribute to the further understanding of the processes by which xylem vessel elements form.