Islets co-engineered with thrombomodulin and CD47 achieve sustained survival in allogeneic recipients without chronic immunosuppression
Shadab Kazmi, Mohammad Tarique, Darshan Badal, Vahap Ulker, Ali Turan, Kathleen M. Yee-Flores, Abdalmonam Jadou Nejma, Esma S. Yolcu, Haval Shirwan
Shadab Kazmi, Mohammad Tarique, Darshan Badal, Vahap Ulker, Ali Turan, Kathleen M. Yee-Flores, Abdalmonam Jadou Nejma, Esma S. Yolcu, Haval Shirwan
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Research Article Immunology

Islets co-engineered with thrombomodulin and CD47 achieve sustained survival in allogeneic recipients without chronic immunosuppression

Abstract

Allogeneic islet transplantation is an effective treatment for type 1 diabetes, but its clinical use is limited by rejection involving innate and adaptive immune responses, requiring lifelong immunosuppression. We herein engineered islets that transiently display 2 immunomodulators chimeric with streptavidin (SA), thrombomodulin (SA-TM) and CD47 (SA-CD47), for localized modulation of both innate and adaptive immune responses. The engineering process did not impact islet viability, glucose responsiveness, and metabolic activity. Intraportal transplantation into allogeneic recipients achieved sustained survival, with 8 out of 11 grafts surviving 120–330 days without immunosuppression. In contrast, non-engineered islets were acutely rejected (median survival time [MST] = 12 days), while islets engineered with SA-TM showed delayed rejection (MST = 13.5 days) and those with SA-CD47 exhibited prolonged survival (MST = 24 days). Double-engineered islets generated a localized tolerogenic immune environment characterized by low frequencies of inflammatory innate immune cells and increased frequencies of M2 macrophages, myeloid-derived suppressor cells, and CD4+FoxP3+ T regulatory cells. The transcriptomic analysis showed downregulation of proinflammatory and upregulation of immune regulatory pathways. Our results demonstrate that transient co-display of immunomodulatory molecules on the islet surface is a versatile platform with significant translational potential for islet transplantation.

Authors

Shadab Kazmi, Mohammad Tarique, Darshan Badal, Vahap Ulker, Ali Turan, Kathleen M. Yee-Flores, Abdalmonam Jadou Nejma, Esma S. Yolcu, Haval Shirwan

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Figure 1

Engineering islets with SA-TM and SA-CD47 proteins does not affect their viability or function.

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Engineering islets with SA-TM and SA-CD47 proteins does not affect their...
(A) Schematic illustration showing stepwise engineering of pancreatic islets. BALB/c pancreatic islets were surface modified with biotin followed by incubation with SA-chimeric proteins. (B) Representative images of double SA-TM and SA-CD47 co-engineered islets. Islets were biotinylated (15 μM) followed by co-engineering with 6.2 μg SA-TM and 0.8 μg SA-CD47 per 1000 islets. Confocal microscopy images of double-engineered islets using anti-SA–Texas red (blue), anti–human TM–FITC (green), anti-CD47–APC (red), and merged images and un-engineered islets used as negative control. (C) Glucose-stimulated insulin secretion conducted on islets without engineering and those engineered with single or both proteins. Islets were cultured in low (3.5 mM) and high (16.5 mM) glucose concentrations followed by the quantification of secreted insulin using ELISA (n = 4–5). (D) Stimulation index (mean secreted insulin in high glucose/mean secreted insulin in low glucose) of the data shown in C. (E) Cell viability and functional activity of engineered islets assessed using an Alamar blue cell viability assay (n = 3). Data are presented as mean ± SD with no statistically significant differences as assessed using 1-way ANOVA with Tukey’s post hoc test.