Mìžnarodnij Endokrinologìčnij Žurnal (Oct 2018)

Role of Foxo1 gene expression in mechanism of antihypertrophic action of metformin in cardiomyocytes

  • N.V. Pasiechko,
  • H.Ya. Loi,
  • M.M. Korda,
  • O.M. Oleshchuk

DOI
https://doi.org/10.22141/2224-0721.14.7.2018.148779
Journal volume & issue
Vol. 14, no. 7
pp. 705 – 711

Abstract

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Background. Diabetic cardiomyopathy is the leading cause of mortality in patients with type 2 diabetes mellitus. Hypertrophy of cardiomyocytes is one of the main pathomorphological signs of diabetic cardiomyopathy development. Metformin, the first-line drug for the treatment of type 2 diabetes mellitus, along with hypoglycaemic effects, exerts cardioprotective effects. However, the mechanism of metformin action in cardiomyocytes remains unclear. The purpose of the study was to investigate the role of Foxo1 gene expression in the mechanism of antihypertrophic action of metformin in cardiomyocytes. Materials and methods. H9C2 cells were transfected with siRNA Fохо1 and siRNA negative control. Cells were deprived in 0% medium for 24 hours, treated with metformin (5mM) 30 min before cell stress, then put into hypoxic chamber for 16 hours and reoxygenated for 4 hours. Cell area was quantified using ImageJ. Knockdown efficiency was confirmed by real time polymerase chain reaction. Results. At the normal functioning of Fохо1 gene, metformin has the expressed antihypertrophic action under hypoxia. However, blocking Fохо1 gene expression deprives preparation of this effect and causes the hypertrophy of Н9С2 cells in all conditions of the experiment. Conclusions. The strong hypertrophic response in the group of H9C2 cells transfected with siRNA Foxo1 cultured under hypoxia with metformin treatment may be a result of following mechanisms: a) metformin prevents hypertrophy through Foxo1 pathway, thus, Foxo1 silencing totally blocked metformin protective effects on H9C2 hypertrophy; b) metformin protects against hypoxia independently of Foxo1 pathway, therefore, strong hypertrophy of metformin-treated cells incubated in hypoxia is the result of Foxo1 knockdown, a potent hypertrophic stimulus. Consequently, further investigations are still required to clarify the mechanisms by which metformin exerts its cardioprotective effects.

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