The DNA methyltransferase DNMT3A contributes to autophagy long-term memory

Area of Science:

• Cellular Biology
• Molecular Biology
• Epigenetics

Background:

• Macroautophagy/autophagy is a crucial cellular process for maintaining homeostasis and responding to stress.
• Microtubule-associated protein 1 light chain 3 (MAP1LC3) isoforms are essential components of the autophagy machinery.
• The long-term consequences of transient autophagy stimulation are not fully understood.

Purpose of the Study:

• To investigate the effect of brief autophagy induction on MAP1LC3 expression.
• To elucidate the molecular mechanisms underlying the observed changes in MAP1LC3 expression.
• To determine if this phenomenon occurs in vivo.

Main Methods:

• In vitro cell culture experiments to induce autophagy and measure MAP1LC3 expression.
• DNA methylation analysis of MAP1LC3 loci using de novo DNA methyltransferase DNMT3A.
• In vivo studies in zebrafish larvae and mice exposed to transient autophagy stimuli.

Main Results:

• Transient autophagy induction led to a persistent downregulation of MAP1LC3 isoforms.
• DNA methylation of MAP1LC3 loci by DNMT3A was identified as the mechanism for transcriptional silencing.
• Downregulation of MAP1LC3 was confirmed in vivo in zebrafish and mice.

Conclusions:

• Autophagy induction establishes an epigenetic memory through DNA methylation of MAP1LC3.
• This epigenetic regulation provides a mechanism for long-term changes in autophagy capacity.
• The findings offer insights into autophagy decline during aging and disease, and potential impacts of interventions.