Human IL10 mRNA

Mesenchymal stem cells (MSCs) are used in various studies to induce immunomodulatory effects in clinical diseases associated with immune dysregulation, such as graft-versus-host disease (GvHD). However, most of these clinical trials have failed to advance beyond early phase II studies due to limited efficacy. Various approaches have been evaluated to enhance the potency of MSCs. IL-10 is an anti-inflammatory cytokine known to modulate immune responses in GvHD. Here, researchers evaluated the feasibility of transfecting IL-10 mRNA to enhance the therapeutic potential of MSCs. IL-10 mRNA-engineered MSCs (eMSCs-IL10) maintained high levels of IL-10 expression even after freeze-thaw. IL-10 mRNA transfection did not appear to alter the intrinsic properties of MSCs. Compared with naïve MSCs, eMSCs-IL10 significantly suppressed T cell proliferation in vitro. In a mouse graft-versus-host disease (GvHD) model, eMSCs-IL10 induced a reduction in the levels of potent proinflammatory cytokines in plasma and suppressed CD4+ and CD8+ T cell proliferation in the spleen. In summary, these studies demonstrate the feasibility of enhancing the immunomodulatory effects of MSCs by IL-10 mRNA transfection. Non-viral transfection techniques have the potential to produce safe and effective MSC products for the treatment of clinical diseases associated with immune dysregulation, such as GvHD.

The researchers transfected MSCs with human IL-10 (hIL-10) and performed time course experiments to determine IL-10 mRNA levels in IL-10 mRNA engineered MSCs (eMSC-IL10) and IL-10 protein secretion in conditioned culture medium (CCM). First, high levels of IL-10 mRNA were detected in eMSCs-IL10 by real-time PCR, while IL-10 mRNA was barely detectable in naïve MSCs. As shown in Figure 1B, naïve MSCs secreted almost no IL-10, while the IL-10 concentration in the CCM of eMSCs-IL10 reached approximately 40,000 pg/mL 6 hours after transfection. After one day of culture of eMSCs-IL10, the amount of IL-10 peaked and then began to decline. By day 4, the concentration had dropped by more than 50% from the peak. However, this level was still approximately 13,200-fold higher than that of naïve MSCs. Therefore, hIL-10 was efficiently secreted from eMSCs-IL10. The researchers envisioned that the eMSCs-IL10 product might need to be cryopreserved before clinical application. Therefore, they optimized the production protocol to ensure that optimal IL-10 secretion levels were maintained after cryopreservation and thawing. Robust IL-10 secretion was detected after 1 day of culture of thawed eMSCs-IL10 (Figure 1C).

Figure 1. Characteristics of IL-10 secretion from eMSCs -IL10. (Zhang C, et al., 2021)