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Sustained Administration of β-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Poly(lactic-co-glycolic acid) Microspheres
Published on: November 5, 2016
Transforming growth factor-beta signaling is enhanced following mitomycin-C treatment of islet xenograft
1Department of Surgery, Fukushima Medical University, Fukushima, Japan.
Abstract:
Mitomycin-C (MMC) is categorized as an agent that causes genotoxic stress by triggering various intracellular signaling pathways. We have previously shown that MMC pretreatment of highly immunogenic crude islets leads to significant prolongation of graft survival in a rat-to-mouse model. In the present study, we examined whether TH1/TH2 cytokine, including the inflammatory cytokines interferon-gamma and interleukin (IL)-2, or the Th2 group, IL-4, IL-10, TNF-alpha, IL-1 beta, IL-6, GM-CSF, and transforming growth factor (TGF)-beta were up-regulated or down-regulated following MMC treatment of islets. We found changes in TGF-beta messenger RNA (mRNA) transcription as the only events among the measured cytokines. TGF-beta concentration was elevated in blebs formed under the kidney capsule, but not in the serum or ascites among animals given MMC-treated islets than in animals given untreated islets, suggesting local processes induced by MMC might inhibit xenograft rejection.
Insights
Mitomycin-C (MMC) pretreatment of islets enhances graft survival by altering local TGF-beta levels. This suggests MMC-induced changes may inhibit xenograft rejection through localized immune modulation.
Area of Science:
- Immunology
- Transplantation Biology
- Molecular Medicine
Background:
- Mitomycin-C (MMC) induces genotoxic stress and has previously shown to prolong graft survival.
- Understanding the immunomodulatory effects of MMC on islets is crucial for improving xenotransplantation outcomes.
Purpose of the Study:
- To investigate the impact of MMC treatment on islet cytokine profiles, specifically TH1/TH2 cytokines.
- To determine if MMC affects the expression of key inflammatory and regulatory cytokines, including TGF-beta.
Main Methods:
- Islets were pretreated with Mitomycin-C (MMC).
- Expression levels of various cytokines (IFN-gamma, IL-2, IL-4, IL-10, TNF-alpha, IL-1 beta, IL-6, GM-CSF, TGF-beta) were analyzed.
- TGF-beta mRNA transcription and protein concentration in serum, ascites, and subcapsular blebs were measured.
Main Results:
- MMC treatment altered TGF-beta messenger RNA (mRNA) transcription as the sole observed cytokine change.
- Elevated TGF-beta concentration was detected in local blebs under the kidney capsule in MMC-treated groups.
- No significant changes in TGF-beta levels were found in serum or ascites compared to controls.
Conclusions:
- Mitomycin-C (MMC) treatment of islets specifically upregulates local TGF-beta production.
- These localized TGF-beta changes suggest a potential mechanism for inhibiting xenograft rejection.
- Further research into MMC's role in modulating the local tumor microenvironment could enhance transplantation success.
