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Updated: Sep 15, 2025
3D Visualization of Retinal Vascular Pericytes in Mice by Immunostaining
Published on: November 1, 2024
Targeting pericytes in the retina: characterization of the inducible NG2-CreERT2 knock-in mouse model
Julia Preishuber-Pflügl1, Susanne Maria Brunner1, Wenhui Huang2
1Research Program for Experimental Ophthalmology and Glaucoma Research, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University Salzburg, Austria.
Insights
A new mouse model using NG2-CreERT2 improved pericyte (PC) labeling in the retina. This enhanced labeling is crucial for studying blood vessel function and regeneration, overcoming limitations of previous models.
Area of Science:
- Vascular Biology
- Cell Biology
- Regenerative Medicine
Background:
- Pericytes (PCs) are crucial mural cells regulating blood vessel stability and function, forming essential barriers like the blood-retinal barrier.
- PCs are implicated in wound healing and tissue regeneration, making them a target for modulating scarring.
- Identifying specific molecular markers for PCs is challenging due to heterogeneous expression patterns.
Purpose of the Study:
- To develop and assess a novel inducible reporter mouse model for efficient pericyte labeling in the retina.
- To overcome the limitations of low labeling efficiency observed in previous NG2-CreERTM-tdTomato models.
- To enable reliable cell tracing for studying pericyte function in retinal vascular research.
Main Methods:
- Crossbreeding of the NG2-CreERT2 knock-in mouse with the tdTomato Ai9 reporter mouse.
- Administration of tamoxifen (TAM) to induce Cre-mediated recombination and reporter gene expression.
- Assessment of tdTomato expression specifically in retinal pericytes and vascular smooth muscle cells.
Main Results:
- The NG2-CreERT2 model demonstrated restricted tdTomato expression to mural cells, including pericytes on capillaries and smooth muscle cells on larger vessels.
- Significantly increased pericyte labeling efficiency in the superficial retinal layer compared to previous models (68.5–70.2% vs. 21.9–35.5%).
- The enhanced labeling provides a more reliable tool for pericyte fate tracing and functional studies.
Conclusions:
- The NG2-CreERT2 x Ai9 mouse model offers a substantial improvement in tamoxifen-inducible pericyte labeling efficiency in the retina.
- This model is suitable for detailed investigation of pericyte biology, including their roles in vascular maintenance and regeneration.
- The improved labeling facilitates future research into therapeutic strategies targeting pericytes for retinal diseases and scarring.
Abstract:
Pericytes (PCs) are mural cells embedded in a common basement membrane with endothelial cells (ECs) on capillaries. They are key players in the regulation of stability and function of blood vessels and are an essential component of the blood-brain and blood-retinal barrier. In addition, PCs are reported to be involved in wound healing and tissue regeneration and represent a promising target for the modulation of scarring processes. Due to their heterogeneous expression pattern, a single specific molecular marker for PCs remains elusive. Inducible reporter mouse models represent a frequently used tool for tracing the fate of a specific cell type, via the expression of a fluorescence reporter protein in the target cell following tamoxifen (TAM) induction. In a recent study, we characterized the TAM-inducible reporter mouse model NG2-CreERTM-tdTomato and demonstrated specific but marginal PC labeling in the retinal capillary plexuses with mean values ranging from 21.9 to 35.5 %. Since such a low labeling efficiency is not sufficient for reliable cell tracing, we characterized a TAM-inducible Cre mouse model expressing the enhanced estrogen receptor ERT2 in the present work. The NG2-CreERT2 knock-in mouse was crossbred with the tdTomato Ai9 reporter mouse to assess efficiency of PC labeling in the retina. The expression of tdTomato was restricted to mural cells, labeling vascular smooth muscle cells on larger vessels and PCs on capillaries. The use of the CreERT2 mouse resulted in an increased percentage of labeled PCs in the superficial layer of the retina with mean values ranging from 68.5 to 70.2 %.
