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Paracrine effects of mesenchymal stem cells-conditioned medium on microglial cytokines expression and nitric oxide
Yin Yin Ooi1, S Thameem Dheen, Samuel Sam Wah Tay
1Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Background/Aim:
Microglia, the resident macrophages in the central nervous system, secrete various proinflammatory cytokines and undergo proliferation upon activation in various neurodegenerative diseases. Activation of microglia has been implicated in exacerbation of various neurodegenerative diseases. Recently, it has been proposed that mesenchymal stem cells (MSC) have immunosuppressive properties and the potential to moderate inflammation. This study aimed to elucidate the effects of MSC-conditioned medium (MSC-CM) in modulating microglial activation by analyzing microglial proinflammatory and anti-inflammatory factors [interleukin (IL)-6, tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS) and IL-10], signaling pathway molecules [NFκB, c-Jun N-terminal kinase (JNK) and MKP-1) and NO production.
Methods:
Immortalized murine microglia cell line, BV2 microglia and primary microglia isolated from C57BL/6 mouse pup brains were used in this study. Mouse MSC were isolated from the male C57BL/6 mouse tibia and fibula. The effects of MSC-CM on the expression of inflammatory cytokines and signaling molecules in microglia were elucidated using RT-PCR, immunofluorescence analysis and Western blot analysis. NO production in microglia was assessed using a Griess kit.
Results:
MSC-CM significantly reduced the mRNA and protein expression levels of proinflammatory cytokines (IL-6 and TNF-α) in microglia activated by lipopolysaccharide (LPS). In addition, MSC-CM significantly reduced the protein expression of NFκB, JNK and c-Jun, but increased the expression levels of IL-10 and MKP-1 in activated BV2 microglia. NO production and iNOS expression by BV2 microglia in MSC-CM were increased.
Conclusions:
Overall, our findings suggest that MSC immunomodulate microglial activities through paracrine effects.
Insights
Mesenchymal stem cells (MSC) can modulate microglial activation. MSC-conditioned medium (MSC-CM) reduced proinflammatory factors and signaling molecules while increasing anti-inflammatory factors in activated microglia, suggesting paracrine immunomodulation.
Area of Science:
- Neuroscience
- Immunology
- Stem Cell Biology
Background:
- Microglia, the brain's immune cells, become activated and release inflammatory cytokines in neurodegenerative diseases.
- Activated microglia can worsen neurodegenerative conditions.
- Mesenchymal stem cells (MSC) show potential for immune suppression and inflammation moderation.
Purpose of the Study:
- To investigate the effects of MSC-conditioned medium (MSC-CM) on microglial activation.
- To analyze how MSC-CM modulates proinflammatory and anti-inflammatory factors in microglia.
- To examine the impact of MSC-CM on key signaling pathways and nitric oxide production.
Main Methods:
- Utilized BV2 microglia cell line and primary mouse microglia.
- Isolated mouse mesenchymal stem cells (MSC).
- Assessed cytokine and signaling molecule expression via RT-PCR, immunofluorescence, and Western blot; measured nitric oxide (NO) production using a Griess kit.
Main Results:
- MSC-CM significantly decreased mRNA and protein levels of IL-6 and TNF-α in LPS-activated microglia.
- MSC-CM reduced NFκB, JNK, and c-Jun protein expression but increased IL-10 and MKP-1 in activated BV2 microglia.
- MSC-CM increased NO production and iNOS expression in BV2 microglia.
Conclusions:
- MSC-CM effectively modulates microglial activation.
- MSC-CM exerts immunomodulatory effects on microglia through paracrine signaling.
- These findings highlight MSC-CM's potential in managing neuroinflammation.
Related Concept Videos
01:19Mesenchymal Stem Cells
01:21Paracrine Signaling