MicroRNA-Mediated Down-Regulation of M-CSF Receptor Contributes to Maturation of Mouse Monocyte-Derived Dendritic
Joey Riepsaame1, Adri van Oudenaren, Berlinda J H den Broeder
1Department of Immunology, Erasmus University Medical Center , Rotterdam , Netherlands.
Abstract:
Dendritic cell (DC) maturation is a tightly regulated process that requires coordinated and timed developmental cues. Here we investigate whether microRNAs are involved in this process. We identify microRNAs in mouse GM-CSF-generated, monocyte-related DC (GM-DC) that are differentially expressed during both spontaneous and LPS-induced maturation and characterize M-CSF receptor (M-CSFR), encoded by the Csf1r gene, as a key target for microRNA-mediated regulation in the final step toward mature DC. MicroRNA-22, -34a, and -155 are up-regulated in mature MHCII(hi) CD86(hi) DC and mediate Csf1r mRNA and protein down-regulation. Experimental inhibition of Csf1r-targeting microRNAs in vitro results not only in sustained high level M-CSFR protein expression but also in impaired DC maturation upon stimulation by LPS. Accordingly, over-expression of Csf1r in GM-DC inhibits terminal differentiation. Taken together, these results show that developmentally regulated microRNAs control Csf1r expression, supplementing previously identified mechanisms that regulate its transcription and protein surface expression. Furthermore, our data indicate a novel function for Csf1r in mouse monocyte-derived DC, showing that down-regulation of M-CSFR expression is essential for final DC maturation.
Insights
MicroRNAs regulate dendritic cell (DC) maturation by targeting the M-CSF receptor (M-CSFR). Down-regulation of M-CSFR is crucial for the final maturation of DCs, impacting their immune function.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Dendritic cell (DC) maturation is a complex process involving precise developmental signals.
- MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and are implicated in various biological processes.
Purpose of the Study:
- To investigate the role of microRNAs in dendritic cell maturation.
- To identify specific microRNAs and their targets involved in the final stages of DC maturation.
- To elucidate the function of M-CSF receptor (M-CSFR) regulation in DC development.
Main Methods:
- Differential expression analysis of microRNAs in mouse monocyte-derived dendritic cells (GM-DCs) during maturation.
- Identification of M-CSFR as a microRNA target.
- Experimental inhibition and overexpression of microRNAs and M-CSFR in vitro.
- Flow cytometry to assess DC maturation markers (MHCII, CD86).
Main Results:
- Several microRNAs, including miR-22, miR-34a, and miR-155, were upregulated in mature DCs.
- These microRNAs were shown to down-regulate M-CSF receptor (M-CSFR) mRNA and protein expression.
- Inhibition of M-CSFR-targeting microRNAs led to sustained M-CSFR expression and impaired LPS-induced DC maturation.
- Overexpression of M-CSFR inhibited terminal differentiation of GM-DCs.
Conclusions:
- Developmentally regulated microRNAs control M-CSF receptor expression during dendritic cell maturation.
- Down-regulation of M-CSFR is essential for the final maturation of monocyte-derived dendritic cells.
- This study reveals a novel regulatory mechanism controlling DC maturation and function.
