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Updated: Aug 10, 2026

Depletion and Reconstitution of Macrophages in Mice
08:50

Depletion and Reconstitution of Macrophages in Mice

Published on: August 1, 2012

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Transient Macrophage Depletion Circumvents Scavenging and Redirects Biodistribution of mRNA-Lipid Nanoparticles

Zhefan Yuan1, Sijin Luozhong1, Ruoxin Li1

  • 1Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States.

ACS Nano
|April 1, 2025
PubMed

Insights

Depleting macrophages enhances messenger RNA (mRNA) -lipid nanoparticle (LNP) delivery to the liver, improving gene editing. However, this depletion disrupts LNP targeting to other organs like the lungs.

Area of Science:

  • Biotechnology
  • Immunology
  • Nanomedicine

Background:

  • Mononuclear phagocytic system (MPS) macrophages clear mRNA-lipid nanoparticles (LNPs), reducing delivery efficiency.
  • Understanding mRNA-LNP-macrophage interactions is key to improving mRNA delivery.

Purpose of the Study:

  • To evaluate how macrophage depletion affects mRNA-LNP transfection and biodistribution.
  • To explore strategies for enhancing mRNA delivery via macrophage modulation.

Main Methods:

  • Temporary depletion of circulating and resident macrophages (MF) in mice.
  • Assessment of mRNA-LNP transfection efficiency and biodistribution with various LNP formulations.
  • Comparison of clinically relevant MF depletion methods.

Main Results:

  • Macrophage depletion significantly enhanced liver expression and in vivo gene editing efficiency of mRNA-LNPs.
  • MF depletion abolished the organ-targeting capabilities of lung-tropic and lymphoid-tropic LNPs.
  • Clinically relevant MF depletion methods showed translational potential for hepatic mRNA delivery.

Conclusions:

  • Macrophage depletion is a versatile strategy to enhance hepatic mRNA delivery, irrespective of the LNP formulation.
  • Macrophage activity is crucial for the organ-specific targeting of non-liver-tropic LNPs.
  • This study provides insights into LNP biodistribution and offers a method to improve mRNA-based therapies.
Keywords:
enhanced efficiencylipid nanoparticlemRNA deliverymacrophage depletionredirect biodistributions

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