AMPK Limits MNNG-Induced Parthanatos by Inhibiting BH3-Only Protein Bim

Area of Science:

• Cellular biology
• Molecular mechanisms of cell death
• Biochemistry

Background:

• Parthanatos is a regulated cell death (RCD) pathway involving poly (ADP-ribose) polymerase-1 (PARP-1).
• The precise mechanisms and physiological roles of parthanatos remain largely unelucidated.
• Understanding RCD pathways is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the molecular mechanisms underlying parthanatos.
• To explore the role of AMP-activated protein kinase (AMPK) in regulating parthanatos.
• To elucidate the relationship between PARP-1, AMPK, and Bcl-2 family proteins in cell death.

Main Methods:

• Biochemical and cellular experiments were performed on human fibrosarcoma HT1080 cells.
• Investigated parthanatos induction by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG).
• Assessed the involvement of BAX/BAK and Bcl-2-interacting mediator of cell death (Bim) in parthanatos pathways.

Main Results:

• MNNG-induced parthanatos proceeds via BAX/BAK or Bim-dependent pathways.
• MNNG activates AMPK through PARP-1-dependent ATP depletion.
• AMPK selectively downregulates Bim-mediated parthanatos by inhibiting Bim upregulation.

Conclusions:

• AMPK signaling, activated by PARP-1-dependent ATP depletion, acts as a negative regulator of parthanatos.
• This study reveals a novel link between AMPK and parthanatos, impacting Bim-mediated cell death.
• Findings offer insights into the physiological significance of parthanatos and potential therapeutic targets.