(I-325) Bioengineered Colon-Specific Immune Niche for the Treatment of Ulcerative Colitis

INTRODUCTION: Ulcerative colitis (UC) is a chronic autoinflammatory bowel disease in which autoreactive T cells and macrophages (MФ) attack healthy colon (COL) epithelial (EPI) cells in the chronic mucosa, leading to chronic inflammation and ulceration. UC symptoms can be debilitating and lead to life-threatening complications, such as bowel perforation and toxic megacolon. While the causes of UC are not fully understood, it is widely believed to be triggered by genetic mutation, immune system malfunction, and environmental factors. Despite intense treatment development efforts, UC remains incurable. Here, we report the bioengineering of an injectable colon-specific immune niche (COIN) as a new organ-specific UC immunotherapy.


MATERIALS and METHODS: A combinational COIN, also known as COMBO COIN, was constructed from a combination of immunosuppressive nanofibers (COMBO ISM NFs), COL EPI cells, and a decellularized colon extracellular biomatrix (COL ECM). The COMBO ISM NFs were engineered with immune suppressive programmed death-ligand 1 (PD-L1), cluster of differentiation 86 (CD86), transforming growth factor-beta 1 mimic peptide and leflunomide to simultaneously anergize autoreactive T cells and polarize pro-inflammatory M1 MФ into pro-regulatory M2 MФ through multiple immunosuppression pathways. Comprehensive T cell inhabitation assay and MФ polarization assay were performed to evaluate the COMBO COIN in vitro. The anit-colitis activities of COMBO COINs were evaluated in the dextran sodium sulfate (DSS)-induced colitis model and IL10 KO mouse model. We further evaluated the use of COMBO COIN to ameliorate immune-mediated colitis in a mouse melanoma model with immune-checkpoint blockade therapy with anti-PD-1 and anti-CTLA-4.


RESULTS, CONCLUSIONS, and DISCUSSIONS: UC is an autoinflammatory disease that affects millions of individuals worldwide and is often refractory to therapeutic intervention. We successfully developed a protocol for the bioengineering of a COMBO COIN for UC treatment. We showed that immunosuppressive NFs functionalized with immunosuppressive immune checkpoint molecules, an immunomodulatory drug and a pro-regulatory cytokine, can inhibit the activation of autoreactive CD8+ T cells in vitro. We demonstrated that COMBO COIN bioengineered from COL EPI cells, decellularized COL ECM, and COMBO ISM NFs effectively ameliorated colitis in DSS colitis and IL10 KO mouse models. Comprehensive immune profiling and immunohistological study revealed the COMBO COIN inhibiting autoreactive CD8+ T cells activation, polarizing pro-inflammatory M1 MФ into pro-regulatory M2 MФ, and allowing healthy intestinal stem cells at the crypts to repair the colon epithelial damages. Furthermore, the immune niche effectively prevented the development of colitis-associated colorectal cancer and ameliorated immune-checkpoint blockade-associated colitis in established syngeneic tumor mouse models. The modular design of the immunosuppressive immune niche enables the on-demand introduction of alternative immunomodulators, targeted cells, and decellularized tissue for the treatment of other autoimmune disease.
[The University of Texas Southwestern Medical Center filed a patent application on the technology and intellectual property reported here.]


ACKNOWLEDGMENTS: We thank the University of Texas Southwestern Medical Center (UTSW) Animal Resource Center, UTSW ARC Diagnostic Laboratory, UTSW ARC Veterinary Services, UT Southwestern Electron Microscopy Facility, UTSW Quantitative Light Microscopy Core, UTSW Flow Cytometry Core, UTSW Histo Pathology Core, UTSW Proteomics Core, UTSW Microarray and Immune Phenotyping Core, UTSW Microbiome Research Lab, UTSW Preclinical Radiation Core Facility and UTSW Whole Brain Microscopy Facility at the University of Texas Southwestern Medical Center, UT Austin Texas Materials Institute, University of North Carolina at Chapel Hill Pathology Services Core, Akina, Inc. (West Lafayette, IN), RayBiotech Life, Inc. (Corners, GA), IDEXX BioAnalytics (Columbia, MI), and iHisto, Inc. (Salem, MA) for their assistance with procedures in this article. UT Southwestern Electron Microscopy Facility is supported by the National Institutes of Health grant 1S10OD021685-01A1. UTSW Quantitative Light Microscopy Core is supported by the National Institutes of Health grant 1S10OD021684-01. UT Austin Texas Materials Institute is supported by the National Science Foundation Major Research Instrument Grant CBET-1624659. Pathology Services Core at the University of North Carolina-Chapel Hill is supported in part by an NCI Centre Core Support Grant 5P30CA016080-42. A.Z.W. was supported by the National Institutes of Health Grants R01GM130590 and R01EB025651.