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Updated: Oct 9, 2025
Isolation and Purification of Murine Cardiac Pericytes
Published on: August 16, 2019
Validation of Specific and Reliable Genetic Tools to Identify, Label, and Target Cardiac Pericytes in Mice
Linda Alex1, Izabela Tuleta1, Venugopal Harikrishnan1
1Department of Medicine (Cardiology) The Wilf Family Cardiovascular Research InstituteAlbert Einstein College of Medicine Bronx NY.
Insights
Researchers identified distinct cardiac pericytes and fibroblasts using specific genetic tools. The inducible NG2-CreER driver is optimal for targeting cardiac pericytes, unlike PDGFR-beta-CreER which lacks specificity.
Area of Science:
- Cardiovascular Biology
- Cell Biology
- Genetics
Background:
- Myocardial pericytes are often misidentified as fibroblasts.
- Lack of specific tools hinders pericyte research in heart disease.
Purpose of the Study:
- To characterize and validate specific strategies for labeling and targeting cardiac pericytes.
- To differentiate pericytes from fibroblasts in the heart.
Main Methods:
- Utilized NG2-DsRed and PDGFRα-EGFP reporter mice for cell identification.
- Generated dual reporter mice (NG2DsRed; PDGFRαEGFP) to assess cell overlap.
- Validated Cre driver specificity by crossing with PDGFRαEGFP reporter mice.
Main Results:
- NG2+ pericytes and PDGFRα+ fibroblasts are distinct populations with unique transcriptional profiles.
- Inducible NG2-CreER specifically traced vascular mural cells, unlike constitutive NG2-Cre or PDGFRβ-CreER.
- PDGFRβ-CreER non-specifically labeled cardiac fibroblasts.
Conclusions:
- Cardiac fibroblasts and pericytes are distinct cell types.
- Inducible NG2-CreER is the optimal driver for targeting cardiac pericytes.
- Inducible PDGFRβ-CreER lacks specificity for pericyte targeting.
Abstract:
Background In the myocardium, pericytes are often confused with other interstitial cell types, such as fibroblasts. The lack of well-characterized and specific tools for identification, lineage tracing, and conditional targeting of myocardial pericytes has hampered studies on their role in heart disease. In the current study, we characterize and validate specific and reliable strategies for labeling and targeting of cardiac pericytes. Methods and Results Using the neuron-glial antigen 2 (NG2)DsRed reporter line, we identified a large population of NG2+ periendothelial cells in mouse atria, ventricles, and valves. To examine possible overlap of NG2+ mural cells with fibroblasts, we generated NG2DsRed; platelet-derived growth factor receptor (PDGFR) αEGFP pericyte/fibroblast dual reporter mice. Myocardial NG2+ pericytes and PDGFRα+ fibroblasts were identified as nonoverlapping cellular populations with distinct transcriptional signatures. PDGFRα+ fibroblasts expressed high levels of fibrillar collagens, matrix metalloproteinases, tissue inhibitor of metalloproteinases, and genes encoding matricellular proteins, whereas NG2+ pericytes expressed high levels of Pdgfrb, Adamts1, and Vtn. To validate the specificity of pericyte Cre drivers, we crossed these lines with PDGFRαEGFP fibroblast reporter mice. The constitutive NG2Cre driver did not specifically track mural cells, labeling many cardiomyocytes. However, the inducible NG2CreER driver specifically traced vascular mural cells in the ventricle and in the aorta, without significant labeling of PDGFRα+ fibroblasts. In contrast, the inducible PDGFRβCreER line labeled not only mural cells but also the majority of cardiac and aortic fibroblasts. Conclusions Fibroblasts and pericytes are topographically and transcriptomically distinct populations of cardiac interstitial cells. The inducible NG2CreER driver optimally targets cardiac pericytes; in contrast, the inducible PDGFRβCreER line lacks specificity.
