Related Experiment Video

Updated: May 19, 2026

Optimized Protocol for Efficient Transfection of Dendritic Cells without Cell Maturation
08:08

Optimized Protocol for Efficient Transfection of Dendritic Cells without Cell Maturation

Published on: July 8, 2011

Internalization of mRNA lipoplexes by dendritic cells

Winni De Haes1, Greet Van Mol, Céline Merlin

  • 1Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine of Antwerp, Nationalestraat 155, Antwerp, Belgium. wdehaes@itg.be

Molecular Pharmaceutics
|August 17, 2012
PubMed

Insights

Lipoplexes carrying mRNA for HIV Gag protein are taken up by dendritic cells, stimulating T cell responses. Uptake for effective protein expression primarily occurs via macropinocytosis and phagocytosis.

Area of Science:

  • Immunology
  • Cell Biology
  • Biotechnology

Background:

  • Lipoplexes are crucial for delivering mRNA into cells, particularly dendritic cells (DCs).
  • Understanding mRNA lipoplex internalization pathways in DCs is vital for optimizing T cell-based immunotherapies, including those for HIV.
  • Previous studies suggest various endocytic pathways mediate lipoplex uptake, but the specific mechanisms for transfection-effective uptake remain unclear.

Purpose of the Study:

  • To elucidate the endocytic pathways responsible for mRNA lipoplex internalization by dendritic cells (DCs).
  • To determine which internalization routes lead to effective protein expression and subsequent T cell stimulation.
  • To investigate the role of macropinocytosis, phagocytosis, and clathrin/caveolae-mediated endocytosis in DC transfection.

Main Methods:

  • Confocal microscopy was used to visualize the colocalization of fluorescently labeled mRNA lipoplexes with late endosomes in DCs.
  • Inhibitors targeting specific endocytic pathways (phagocytosis, macropinocytosis, clathrin-mediated, and caveolae-mediated endocytosis) were employed.
  • Cellular uptake and protein expression levels were quantified following treatment with various endocytic inhibitors.

Main Results:

  • One-third of mRNA lipoplexes colocalized with late endosomes.
  • Inhibitors of macropinocytosis and phagocytosis (Cytochalasin D) significantly reduced lipoplex internalization (50%) and protein expression (70%).
  • Inhibitors targeting other pathways showed varied effects, with Genistein and Dynasore strongly reducing protein expression but not overall uptake, suggesting macropinocytosis and/or phagocytosis are key for transfection-effective uptake.

Conclusions:

  • Transfection-effective internalization of mRNA lipoplexes by DCs predominantly occurs via macropinocytosis and/or phagocytosis.
  • These pathways are critical for achieving therapeutic protein expression from delivered mRNA.
  • The findings provide insights into optimizing lipid-based mRNA delivery systems for enhancing immune responses.

More Related Videos

Isolation And Dendritic Cell-Uptake of Small Extracellular Vesicles from Echinococcus granulosus09:04

Isolation And Dendritic Cell-Uptake of Small Extracellular Vesicles from Echinococcus granulosus

Published on: March 28, 2025

Generation of Human Monocyte-derived Dendritic Cells from Whole Blood07:35

Generation of Human Monocyte-derived Dendritic Cells from Whole Blood

Published on: December 24, 2016

Related Concept Videos

Receptor-mediated Endocytosis01:38

Receptor-mediated Endocytosis

Overview
Receptor-mediated Endocytosis01:20

Receptor-mediated Endocytosis

Receptor-mediated endocytosis is when bulk amounts of specific molecules are imported into a cell after binding to cell surface receptors. The molecules bound to these receptors are taken into the cell through inward folding of the cell surface membrane, which is eventually pinched off into a vesicle within the cell. Structural proteins, such as clathrin, coat the budding vesicle.
Clathrin-Mediated Endocytosis of LDL
One well-characterized example of receptor-mediated endocytosis is the...
Antigen Presenting Cells01:22

Antigen Presenting Cells

The immune system is a complex network of cells and molecules that protects the body from foreign invaders. T cells, a type of white blood cell, play a crucial role in this process. They recognize and attack foreign substances, such as pathogens, that enter the body.
T cells require the help of antigen-presenting cells (APCs), which process foreign antigens into smaller fragments that can be recognized by T cells. These APCs are highly specialized cells that efficiently internalize antigens...
Antigens Involved in Adaptive Immunity01:26

Antigens Involved in Adaptive Immunity

An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Immune Response Against Viral Pathogens01:29

Immune Response Against Viral Pathogens

The immune system's response to viral infections is a complex and coordinated process involving natural killer (NK) cells, T cell-mediated responses, and antibody-mediated responses.
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
Antigen Processing Pathways01:31

Antigen Processing Pathways

MHC molecules are key players in the immune response, enabling T cells to recognize and respond to specific antigens. They are present on the surface of all nucleated cells in the body and are instrumental in presenting antigens to T cells and activating them. T cells recognize the MHC-antigen complex and initiate an immune response. MHC class I and MHC class II are two main types of MHC molecules, each associated with a distinct antigen processing pathway.
MHC Class I: Presenting Endogenous...