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bioRxiv · 10.64898/2025.12.30.697107

Protective IFIH1 variant reduces immune-mediated islet stress and dysfunction in a type 1 diabetes genetic background

Veronese-Paniagua, D. A.·Banks, C.·Bradley, K.·Mukherjee, N.·Gale, S. E.·Hinshaw, K. E.·Meacham, A. M.·Iwaloye, O. F.·Tse, H. M.·Mathews, C. E.·Millman, J. R.
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Abstract

Genome-wide association studies (GWAS) have linked dozens of genetic loci to type 1 diabetes (T1D). The IFIH1 gene, which encodes the double-stranded RNA sensor MDA5, is one such locus. The E627* single nucleotide polymorphism (SNP) in IFIH1 is associated with protection against T1D, while the A946T variant is linked to increased risk. While the E627* variant has been shown to result in a truncated protein and dampen type I interferon (IFN) signaling, its specific role in human pancreatic islet health and function remains unclear. We hypothesized that MDA5627* would protect islet cells from stress-induced dysfunction, identity loss, and cell death. Using CRISPR-Cas9 technology, we introduced the E627* and A946T variants into human pluripotent stem cells (hPSCs) derived from a T1D patient. We differentiated these hPSCs into stem cell-derived islets (SC-islets) and treated them with IFN, poly(I:C), and coxsackievirus B3, an enterovirus implicated in T1D pathogenesis. Using single-cell RNA sequencing and an array of functional assays, we investigated the variant impact on both whole SC-islets and their individual cell populations. Our analysis revealed that SC-islets, and their {beta}, , and {delta} cell subpopulations, harboring the MDA5627* variant exhibit an attenuated immune response to the various stressors compared to MDA5946T cells. We also report unique, cell-type-specific transcriptional responses that vary across variants. Notably, MDA5627* SC-islets showed reduced apoptosis rates and viral genome expression, as well as attenuated negative effects on mitochondrial function and insulin secretion in response to stress. Overall, our findings demonstrate that a clinically relevant MDA5 variant confers protection by dampening stress-mediated transcriptional responses, reducing cell dysfunction, and preventing apoptosis. These insights provide a mechanistic framework for understanding T1D pathogenesis and offer new avenues for developing preventative therapies.

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Veronese-Paniagua, D. A., Banks, C., Bradley, K., Mukherjee, N., Gale, S. E., Hinshaw, K. E., Meacham, A. M., Iwaloye, O. F., Tse, H. M., Mathews, C. E., Millman, J. R.. 2025-12-31. Protective IFIH1 variant reduces immune-mediated islet stress and dysfunction in a type 1 diabetes genetic background. https://doi.org/10.64898/2025.12.30.697107

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