Metformin Reduces Vascular Assembly in High Glucose-Treated Human Microvascular Endothelial Cells in An AMPK-Independent Manner

Autores da FMUP

• Ilda Susana Oliveira Pinto E Ferreira Rodrigues

  Autor

• Raquel Ângela Silva Soares Lino

  Autor

Participantes de fora da FMUP

• Silva, C
• Andrade, S
• Costa, R

Unidades de investigação

• Biomedicina

Abstract

Objective: The aim is to examine the effect of metformin in human microvascular endothelial cells exposed to high glucose (HG) concentration and compare them with the effects of other 5' adenosine monophosphate-activated protein kinase (AMPK) modulators under the same condition. Materials and Methods: In this experimental study, human microvascular endothelial cells (HMECs) were treated with 15 mM metformin, 1 mM 5-aminoimidazol-4-carboxamideribonucleotide (AICAR) and 10 mM compound C in the presence of 20 mM glucose (hyperglycemic condition). Migration, invasion and proliferation were evaluated as well as the capillary-like structures formation. Moreover, the expression of angiogenic genes was assessed. Results: Metformin significantly inhibited vessel formation and migration, although it did not change HMECs proliferation and invasion. In addition, metformin significantly reduced collagen formation as evidenced by histological staining. Concomitantly, expression of several genes implicated in angiogenesis and fibrosis, namely TGF beta 2, VEGFR2, ALK1, JAG1, TIMP2, SMAD5, SMAD6 and SMAD7, was slightly upregulated. Immunostaining for proteins involved in ALK5 receptor signaling, the alternative TGF beta signaling pathway, revealed significant differences in SMAD2/3 expression. Conclusion: Our data showed that metformin prevents vessel assembly in HMECs, probably through an AMPK-independent mechanism. Understanding the molecular mechanisms by which this pharmacological agent affects endothelial dysfunction is of paramount importance and paves the way to its particular use in preventing development of diabetic retinopathy and nephropathy, two processes where angiogenesis is exacerbated.

Keywords

• AICAR; AMPK Signaling; Compound C; Endothelial Cells; Metformin