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Updated: May 2, 2026
Mesenchymal Stem Cell Regulation of Macrophage Phagocytosis; Quantitation and Imaging
Published on: July 16, 2021
Characterization of mesenchymal stem cells under the stimulation of Toll-like receptor agonists
Xi Chen1, Zheng-Yun Zhang, Hao Zhou
1Department of Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
Abstract:
Infective factors cause the perpetuation of inflammation as a result of the permanent exposure of the immune system to exogenous or endogenous products of virus or bacteria. Mesenchymal stem cells (MSCs) can be exposed to this infective environment, which may change the characteristics and therapeutic potency of these MSCs. MSCs have the ability to repair damaged and inflamed tissues and regulate immune responses. In this study, we demonstrated that MSCs express functional Toll-like receptors (TLR) 3 and 4, the Toll-like receptor families that recognize the signals of viral and bacterial mimics, respectively. The specific stimulations did not affect the self-renewal and apoptosis capabilities of MSCs but instead promoted their differentiation into the adipocytes and osteoblasts with the TLR3 ligand. The reverse of these results were obtained with the TLR4 ligand. The migration of the MSCs to stimulate either of the two specific ligands was inhibited at different times, whereas the immunogenicity and immunosuppressive properties of the MSCs were not weakened unlike in the MSCs group. These results suggest that TLR3 and TLR4 stimulation affect the characterization of MSCs.
Insights
Mesenchymal stem cells (MSCs) respond to viral and bacterial signals via Toll-like receptors (TLR) 3 and 4. TLR stimulation alters MSC differentiation and migration but preserves their therapeutic properties.
Area of Science:
- Immunology
- Stem Cell Biology
- Regenerative Medicine
Background:
- Inflammation can be perpetuated by infective factors, affecting the immune system's response.
- Mesenchymal stem cells (MSCs) possess tissue repair and immune regulatory functions, but their therapeutic potential may be altered by inflammatory environments.
- Understanding how MSCs interact with infectious agents is crucial for optimizing their therapeutic applications.
Purpose of the Study:
- To investigate the expression and function of Toll-like receptors (TLR) 3 and 4 on MSCs.
- To determine the impact of TLR3 and TLR4 stimulation on MSC characteristics, including self-renewal, apoptosis, differentiation, migration, immunogenicity, and immunosuppressive properties.
Main Methods:
- MSCs were stimulated with specific ligands for Toll-like receptor 3 (TLR3) and Toll-like receptor 4 (TLR4).
- Assays were performed to evaluate MSC self-renewal, apoptosis, differentiation into adipocytes and osteoblasts, migration, immunogenicity, and immunosuppressive functions.
- Comparative analysis was conducted between stimulated and unstimulated MSC groups.
Main Results:
- MSCs express functional TLR3 and TLR4 receptors.
- TLR3 ligand stimulation promoted MSC differentiation into adipocytes and osteoblasts without affecting self-renewal or apoptosis.
- TLR4 ligand stimulation yielded reverse differentiation effects, and both TLR3 and TLR4 stimulation inhibited MSC migration at different time points.
- Crucially, MSC immunogenicity and immunosuppressive properties remained unaffected by TLR stimulation.
Conclusions:
- TLR3 and TLR4 stimulation significantly influences the characterization of MSCs, particularly their differentiation and migration capabilities.
- Despite alterations in specific functions, the core therapeutic properties of MSCs, such as immunogenicity and immunosuppression, are preserved following TLR stimulation.
- These findings provide insights into modulating MSC behavior for enhanced therapeutic efficacy in inflammatory and infectious conditions.
