Immunosuppressive treatment of chronic auto-immune disorders has been associated with serious side effects which can negatively impact quality of life. Despite advances in therapeutic options, such as targeting tumor necrosis factor, relatively few patients respond to new treatments and for the small number who do respond, substantial risk of adverse side effects remains. Research efforts have shifted towards exploiting the role of myeloid regulatory cells in controlling inflammation, generating effective cell therapies for use in autoimmune disease and transplant recipients. By utilizing in vitro-transcribed mRNA, a cost-effective drug class, the Stephan lab in the Fred Hutch Clinical Research Division developed an effective nanoreagent with the potential for treating patients living with autoimmune disease. Describing the goal of their recent study published in Journal of Controlled Release, Dr Stephan said that “chronic autoimmune diseases, such as Systemic Lupus Erythematosus (SLE), are currently still challenging to manage owing to their clinical heterogeneity and often unknown causes. Therapies now used in the clinic are corticosteroids, antimalarial drugs, or other systemically acting immunosuppressants that are associated with substantial side effects. We explored the use of in vitro transcribed mRNA to rationally reprogram myeloid cells as a strategy to treat autoimmune disease.”
In samples derived from patients with SLE, circulating immune cells, such as macrophages and neutrophils, positively express CD64 an integral membrane glycoprotein. Working with a mouse model that can recreate the effects of progressive SLE in an in vivo setting the authors determined that, as seen in patient samples, immune cells had high expression of CD64 thus confirming its potential as a delivery target. Next, they engineered nanoparticles targeting CD64 expressing cells, and containing in-vitro transcribed mRNA encoding for glucocorticoid-induced leucine zipper (GILZ). The authors postulated that GILZ, a master regulator of inflammation that is expressed at low levels in auto-immune disease, would generate anti-inflammatory actions within the target host if expressed at higher levels. The specificity of these nanoparticles in targeting inflammatory immune cells was confirmed.
The authors then sought to explore the impact of their GILZ nanoparticles in reducing pro-inflammatory effects in SLE. Utilizing their aforementioned in vivo mouse model of SLE, mice were treated with either a control, an inactive treatment or the GILZ mRNA nanoparticles for a period of 6 weeks and were continuously monitored for alterations in disease progression. Excitingly, treatment with the nanoparticles greatly increased the lifespan of the experimental mice, who outlived their control-treated counterparts for a significant period of time. Investigating this further, the authors determined a reduction in anti-double stranded DNA autoantibodies decreasing the risk of common inflammatory effects in SLE. Moreover, auto-immune associated alterations in skin pathology were not observed in GILZ mRNA treated mice to the same extent as in control mice.
To better their understanding of the mechanism of action of these nanoparticles, the authors examined NF-κB activity (a key pro-inflammatory player) across their treatment groups. Transfection with GILZ nanoparticles reduced NF-κB pathway activity, which is consistent with previously reported data. Taking this finding a step further, the authors assessed transcriptional gene signatures of treated versus control SLE mice. Key genes involved in inflammatory processes were downregulated in the GILZ mRNA treated mice including CXCL16, S100A4 and Tlr7. These findings highlight the capability of GILZ mRNA nanoparticles in mediating pro-inflammatory responses. Elaborating on this, Dr Stephan pointed to the clinical translatability of these findings: “We demonstrate in models of SLE that infusions of nanoparticles formulated with mRNA encoding GILZ effectively control the disease. We further establish that these nanoreagents are safe for repeated dosing”.
The future of nanoreagents in treating chronic autoimmune diseases looks bright, with next steps focused on bringing this treatment into the clinical realm. As Dr Stephan explained, “Sanofi has acquired the Fred Hutch spin-out company Tidal Therapeutics, that commercialized this technology to treat autoimmune disease. Sanofi will optimize this nanodrug for clinical translation.”
This work was funded by the Fred Hutchinson Cancer Research Center Immunotherapy Initiative with funds provided by the Bezos Family Foundation, by the Comparative Medicine Shared Resource of the Fred Hutchinson/University of Washington Cancer Consortium and the National Cancer Institute. Dr Stephan was also supported by a 2018 Emerging Leader Award from the Mark Foundation for Cancer Research, a 2018 Investigator Award from the Alliance for Cancer Gene Therapy (ACGT), and an Allen Distinguished Investigator Award from the Paul G. Allen Frontiers Group.
UW/Fred Hutch Cancer Consortium member Matthias Stephan contributed to this work.
Parayath NN, Hao S, Stephan SB, Koehne AL, Watson CE, Stephan MT. Genetic in situ engineering of myeloid regulatory cells controls inflammation in autoimmunity. J Control Release. 2021 Aug 24:S0168-3659(21)00446-6. doi: 10.1016/j.jconrel.2021.08.040. Epub ahead of print. PMID: 34437913.