Several natural promoters are activated by specific extracellular signals or the activation of biological pathways. Therefore, we tested whether pro-inflammatory cytokines could trigger transgene expression in genetically modified MSCs. MSCs increase their immune inhibitory ability upon contact with pro-inflammatory cytokines like IFN-γ, TNF-α, and IL1-β, and a constitutive transgene expression could diminish the advantage of a responsive therapy. Additionally, some diseases, such as rheumatoid arthritis, can occur in flares, making responsive immune inhibition preferable. It was shown that the constitutive presence of immune inhibitory factors in ectopic organs could increase the risk of bacterial infections or autoimmune-like observations. However, MSCs are initially entrapped in the lung, and the subsequent migration is a complex and not fully understood process. To enhance the natural MSC effects, many work groups use genetic modifications to overexpress factors contributing to immune modulation (TGF-β, IL10), migration to inflammatory microenvironments (CXCR4), and other mechanisms. However, many trials show only a limited beneficial effect upon MSC application leading to only a few regulatory authority-approved therapies worldwide. Mesenchymal stromal cells (MSCs) are excessively investigated as a therapeutic option for a broad spectrum of inflammatory diseases in animals and patients. The newly developed promoter elements are potentially interesting for other inflamed tissues, and can be combined with other elements or used in other cell types. These results provide new insights into MSC inflammatory activation and the subsequent translation into a tool for a tailored expression of transgenes in inflammatory microenvironments. Finally, transplanted CXCL11-IL10-MSCs increased CD19+ and CD4+ lymphoid cells, and decreased CD11b+ Ly6g myeloid cells in an ALI mouse model. We observed in transcriptome analyses that IL10 has no effect on MSCs and in ELISA that IL10 is only secreted by our genetically modified and activated CXCL11-IL10-MSCs. However, the CXCL11 promoter showed synergistic activity upon IFN-γ, TNF-α and IL1-β treatment and surpassed the transgene expression height of all tested promoters in the study. The synthetic promoters achieved a high and specific transgene expression upon IFN-γ addition. Finally, we investigated IL10 as a potential immune inhibitory transgene by transcriptome analyses, ELISA and in an acute lung injury mouse model. The constructs with the highest transgene expression upon addition of pro-inflammatory cytokines were compared to vectorized promoters from inflammation-induced genes (CD317, CXCL9, CXCL10, CXCL11 and IDO1). The best candidates were combined with interferon-induced GAS or ISRE DNA motifs. Therefore, we investigated different combinations of general transcription factor elements to achieve a minimal promoter with low basal activity. We designed and tested inflammation-induced promoters to control transgene expression from integrating lentiviral vectors in human umbilical cord MSCs. However, the ectopic secretion of immune inhibitory transgenes increases the chances of infections, and constitutive transgene expression is not necessary for chronic diseases undergoing different inflammatory stages. Many work groups try to improve the therapeutic outcome of MSCs by genetic modification and the constitutive overexpression of immune modulatory transgenes. MSCs are naturally activated by inflammatory signals, which lead to the secretion of immune inhibitory factors in inflamed tissues. Mesenchymal stromal cells (MSCs) are excessively investigated in the context of inflammation-driven diseases, but the clinical results are often moderate.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |