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Updated: May 8, 2026
Isolation, Characterization, and Purification of Macrophages from Tissues Affected by Obesity-related Inflammation
Published on: April 3, 2017
Low density receptor-related protein 1 (LRP1) promotes anti-inflammatory phenotype in murine macrophages
Petra May1, Hans H Bock, Jerzy-Roch Nofer
1Center for Neurosciences, University of Freiburg, Freiburg, Germany.
Abstract:
We have previously reported that apolipoprotein E (apoE), a protein component of very-low-density lipoproteins (VLDL) and high-density lipoproteins and a potent plasma-borne atheroprotective factor, exerts anti-inflammatory activity in macrophages by switching the activation profile from M1 ("classic") to M2 ("alternative") in a process involving signaling via low-density lipoprotein receptor (LDLR) family members including the VLDL receptor (VLDLR) or apoE receptor-2 (apoER2). The present study was undertaken to investigate whether LDLR-related protein 1 (LRP-1), another member of the LDLR family and a ubiquitously expressed multifunctional cell surface receptor, modulates M1→M2 conversion in murine macrophages. We investigate bone marrow or peritoneal macrophages isolated from wild-type C57/Bl6 mice or mice with conditional inactivation of the LRP-1 gene in the myeloid lineage for the expression of polarization markers. Our results suggest that the deficiency of LRP-1 down-regulates M2 marker expression in macrophages, while enhancing the macrophage response to M1 stimuli. To our knowledge, this is the first demonstration that LRP-1 affects macrophage polarization and promotes the development of an anti-inflammatory M2 functional phenotype.
Insights
Low-density lipoprotein receptor-related protein 1 (LRP-1) deficiency impairs macrophage polarization towards an anti-inflammatory M2 phenotype. This study reveals LRP-1’s crucial role in promoting M2 macrophage function.
Area of Science:
- Immunology
- Molecular Biology
- Cardiovascular Research
Background:
- Apolipoprotein E (apoE) exhibits anti-inflammatory properties by promoting M2 macrophage polarization via Low-Density Lipoprotein Receptor (LDLR) family members.
- The role of LDLR-related protein 1 (LRP-1) in macrophage polarization remains unexplored.
Purpose of the Study:
- To investigate the role of LRP-1 in modulating macrophage polarization from M1 to M2 phenotypes.
- To determine if LRP-1 influences the development of anti-inflammatory M2 macrophage function.
Main Methods:
- Isolation of bone marrow and peritoneal macrophages from wild-type and myeloid-specific LRP-1 knockout mice.
- Analysis of macrophage polarization markers to assess M1 and M2 phenotypes.
Main Results:
- LRP-1 deficiency was found to down-regulate M2 marker expression in macrophages.
- Absence of LRP-1 enhanced the macrophage response to M1 stimuli.
- This study is the first to demonstrate LRP-1's impact on macrophage polarization.
Conclusions:
- LRP-1 plays a critical role in promoting macrophage polarization towards an anti-inflammatory M2 phenotype.
- LRP-1 deficiency skews macrophage polarization towards an M1-dominant profile, potentially impacting inflammatory responses.
