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DNMT1 mRNA Transfer VIA Macrophage-Derived Extracellular Vesicles Following LPS Exposure Regulates TNFα Gene

Courtney Collins1, Bommana Raghunath Reddy2, Sumit Verma2

  • 1Department of Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio.

Shock (Augusta, Ga.)
|December 22, 2025
PubMed
Abstract

Insights

Lipopolysaccharide (LPS) exposure causes immune dysfunction in macrophages. DNA methyltransferase 1 (DNMT1) within extracellular vesicles is responsible for silencing TNFα gene expression, offering a therapeutic target.

Area of Science:

  • Immunology
  • Epigenetics
  • Molecular Biology

Background:

  • Lipopolysaccharide (LPS) exposure induces prolonged immune dysfunction in human macrophages.
  • Epigenetic methylation of pro-inflammatory genes is implicated in this immune dysfunction.
  • Extracellular vesicles (EVs) transfer DNA methyltransferase (DNMT) mRNA to recipient cells, leading to gene silencing.

Purpose of the Study:

  • To identify the specific DNA methyltransferase (DNMT) isoform responsible for LPS-induced gene silencing in macrophages.
  • To investigate the role of DNMT mRNA carried by extracellular vesicles (EVs) in this process.

Main Methods:

  • Human macrophages were exposed to LPS to generate EVs containing DNMT mRNA.
  • Small interfering RNAs (siRNAs) targeting DNMT isoforms (1, 3A, 3B) were used to create EVs with specific DNMT mRNA cargo.
  • Recipient macrophages were treated with these engineered EVs, and methylation of TNFα was assessed via bisulfate sequencing.

Main Results:

  • siRNAs effectively knocked down DNMT isoforms.
  • LPS-exposed macrophages showed increased DNMT1 mRNA levels.
  • EVs from LPS-exposed macrophages contained reduced DNMT1 mRNA, leading to decreased TNFα methylation and increased TNFα mRNA expression in recipient cells.

Conclusions:

  • DNA methyltransferase 1 (DNMT1) is the primary mRNA isoform mediating methylation and gene silencing of TNFα in human macrophages post-LPS exposure.
  • Targeting DNMT1 may offer a therapeutic strategy to mitigate LPS-induced epigenetic modifications and immune dysfunction.
Keywords:
DNA methyltransferaseExtracellular vesiclesgene silencingimmunosuppression

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