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Updated: Jun 26, 2026
Chondrogenic Pellet Formation from Cord Blood-derived Induced Pluripotent Stem Cells
Published on: June 19, 2017
Blocking vascular endothelial growth factor with soluble Flt-1 improves the chondrogenic potential of mouse skeletal
Seiji Kubo1, Gregory M Cooper, Tomoyuki Matsumoto
1Children's Hospital of Pittsburgh, and University of Pittsburgh, Pittsburgh, Pennsylvania 15213-2582, USA.
Objective:
To investigate the effect of vascular endothelial growth factor (VEGF) stimulation and the effect of blocking VEGF with its antagonist, soluble Flt-1 (sFlt-1), on chondrogenesis, using muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle.
Methods:
The direct effect of VEGF on the in vitro chondrogenic ability of mouse MDSCs was tested using a pellet culture system, followed by real-time quantitative polymerase chain reaction (PCR) and histologic analyses. Next, the effect of VEGF on chondrogenesis within the synovial joint was tested, using genetically engineered MDSCs implanted into rat osteochondral defects. In this model, MDSCs transduced with a retroviral vector to express bone morphogenetic protein 4 (BMP-4) were coimplanted with MDSCs transduced to express either VEGF or sFlt-1 (a VEGF antagonist) to provide a gain- and loss-of-function experimental design. Histologic scoring was used to compare cartilage formation among the treatment groups.
Results:
Hyaline-like cartilage matrix production was observed in both VEGF-treated and VEGF-blocked (sFlt-1-treated) pellet cultures, but quantitative PCR revealed that sFlt-1 treatment improved the expression of chondrogenic genes in MDSCs that were stimulated to undergo chondrogenic differentiation with BMP-4 and transforming growth factor beta3 (TGFbeta3). In vivo testing of articular cartilage repair showed that VEGF-transduced MDSCs caused an arthritic change in the knee joint, and sFlt-1 improved the MDSC-mediated repair of articular cartilage, compared with BMP-4 alone.
Conclusion:
Soluble Flt-1 gene therapy improved the BMP-4- and TGFbeta3-induced chondrogenic gene expression of MDSCs in vitro and improved the persistence of articular cartilage repair by preventing vascularization and bone invasion into the repaired articular cartilage.
Insights
Blocking vascular endothelial growth factor (VEGF) with soluble Flt-1 (sFlt-1) enhanced muscle-derived stem cell (MDSC) chondrogenesis and improved articular cartilage repair by preventing vascularization. This suggests sFlt-1 therapy holds promise for regenerative medicine.
Area of Science:
- Regenerative Medicine
- Stem Cell Biology
- Vascular Biology
Background:
- Chondrogenesis, the process of cartilage formation, is crucial for articular cartilage repair.
- Vascular endothelial growth factor (VEGF) plays a complex role in stem cell differentiation and tissue repair.
- Muscle-derived stem cells (MDSCs) are a promising cell source for cartilage regeneration.
Purpose of the Study:
- To investigate the impact of VEGF stimulation and blockade on chondrogenesis using MDSCs.
- To evaluate the efficacy of soluble Flt-1 (sFlt-1), a VEGF antagonist, in promoting cartilage repair in vivo.
Main Methods:
- In vitro pellet cultures of MDSCs were used to assess chondrogenesis with VEGF stimulation and sFlt-1 blockade.
- Real-time quantitative PCR and histologic analyses were performed to evaluate gene expression and matrix production.
- Genetically engineered MDSCs expressing VEGF or sFlt-1 were implanted into rat osteochondral defects to assess in vivo cartilage repair.
Main Results:
- While VEGF and sFlt-1 both supported hyaline-like cartilage matrix production in vitro, sFlt-1 treatment enhanced chondrogenic gene expression when MDSCs were stimulated with BMP-4 and TGFbeta3.
- In vivo, VEGF-transduced MDSCs led to arthritic changes, whereas sFlt-1 treatment improved MDSC-mediated articular cartilage repair compared to BMP-4 alone.
- sFlt-1 treatment prevented vascularization and bone invasion into the repaired cartilage.
Conclusions:
- Soluble Flt-1 gene therapy significantly improved BMP-4- and TGFbeta3-induced chondrogenic gene expression in MDSCs.
- sFlt-1 enhanced the persistence of articular cartilage repair by inhibiting vascularization and subsequent bone invasion.
- Blocking VEGF signaling with sFlt-1 represents a potential therapeutic strategy for improving cartilage regeneration.
