Metformin Attenuates ROS via FOXO3 Activation in Immune Cells

Front Immunol. 2021 Apr 19:12:581799. doi: 10.3389/fimmu.2021.581799. eCollection 2021.

Abstract

Forkhead box O 3 (FOXO3) is a transcription factor involved in cell metabolism, inflammation and longevity. Here, we investigated if metformin can activate FOXO3 in human immune cells and affects the subsequent level of reactive oxygen/nitrogen species (ROS/RNS) in immune cells. AMP-activated protein kinase (AMPK) and FOXO3 activation were investigated by immunoblot or flow cytometry (FC) analysis, respectively. FOXO3 target gene expression was quantified by real-time PCR. ROS/RNS measurement using dichlorodihydrofluorescein diacetate (DCFH-DA) dye was investigated by FC. The role of the FOXO3 single nucleotide polymorphisms (SNPs) rs12212067, rs2802292 and rs12206094 on ROS/RNS production was studied using allelic discrimination PCR. Metformin induced activation of AMPK (pT172) and FOXO3 (pS413). ROS/RNS level was reduced in immune cells after metformin stimulation accompanied by induction of the FOXO3 targets mitochondrial superoxide dismutase and cytochrome c. Studies in Foxo3 deficient (Foxo3-/- ) mouse splenocytes confirmed that metformin mediates its effects via Foxo3 as it attenuates ROS/RNS in myeloid cells of wildtype (WT) but not of Foxo3-/- mice. Our results suggest that FOXO3 can be activated by metformin leading to reduced ROS/RNS level in immune cells. This may add to the beneficial clinical effects of metformin observed in large cohort studies on longevity, cardiovascular and cancer risk.

Keywords: AMPK; FOXO3; immune cells; metformin; reactive oxygen species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / metabolism
  • Animals
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Enzyme Activation / drug effects
  • Forkhead Box Protein O3 / genetics
  • Forkhead Box Protein O3 / metabolism*
  • Gene Expression / drug effects
  • Humans
  • Hypoglycemic Agents / pharmacology
  • Immune System / cytology
  • Immune System / drug effects*
  • Immune System / metabolism
  • Metformin / pharmacology*
  • Mice
  • Mice, Knockout
  • Polymorphism, Single Nucleotide
  • Reactive Oxygen Species / metabolism*
  • Spleen / cytology
  • Spleen / drug effects
  • Spleen / metabolism

Substances

  • Forkhead Box Protein O3
  • Hypoglycemic Agents
  • Reactive Oxygen Species
  • Metformin
  • AMP-Activated Protein Kinases