Objective
This study aims to develop a one-time, durable immune-engineering therapy for T1D that reduces autoimmune inflammation in the pancreas and supports long term preservation of insulin-producing β-cells in T1D. To accomplish this, we will use lentivirus to genetically modify CD34+ HSPCs to express a T-cell recognizing CAR, enabling their macrophage progeny to interact with autoreactive T cells and activate anti-inflammatory signaling. The study will test whether this strategy produces sustained immunoregulatory macrophage polarization that translates to measurable therapeutic benefit, including reduced insulitis, preservation of β-cell mass and improved glycemic control. These evaluations will be conducted through complementary in vitro and in vivo studies, with in vivo therapeutic assessment performed in the NOD model of autoimmune diabetes.
Background Rationale
T1D results from an immune-mediated attack on insulin-producing β-cells. Although insulin replacement is essential for survival, it does not address the underlying immune dysfunction that drives progressive β-cell loss. A longstanding goal in the field has been to develop therapies that slow or prevent β-cell destruction by modifying the immune response. However, achieving durable benefit remains challenging because immune pathways are complex, redundant, and capable of re-activating inflammatory mechanisms over time. This has motivated interest in therapies that can provide long-term immune regulation without requiring continuous broad immunosuppression.
Early in T1D progression, inflammatory immune activity is concentrated in and around the pancreatic islets. While autoreactive T cells are key mediators of β-cell killing, the local tissue environment strongly influences how inflammation develops and persists. In particular, macrophages—innate immune cells that are abundant in the pancreas during T1D—play a central role in shaping the inflammatory landscape. Macrophages influence antigen presentation, cytokine production, and recruitment or activation of additional immune cells. Importantly, macrophages are not fixed in function; they exhibit substantial plasticity and can adopt either inflammatory phenotypes that amplify tissue damage or immunoregulatory phenotypes that suppress inflammation and support repair.
This macrophage plasticity provides a strong biological rationale for therapeutic intervention. Evidence from multiple systems suggests that shifting macrophages away from pro-inflammatory programs and toward immune-regulating programs can reduce tissue inflammation and improve outcomes in autoimmune and inflammatory diseases. In T1D, macrophages are positioned at the interface of immune activation and tissue injury, making them attractive candidates for approaches aimed at rebalancing the pancreatic immune environment. Unlike strategies that target a single inflammatory molecule, modulating macrophage behavior has the potential to broadly reshape immune signaling networks within tissue, including cytokine profiles and immune-cell interactions.
Another key challenge is therapeutic durability. Many immunomodulatory therapies require repeated administration, and their benefits may wane as immune activity adapts or returns. Long-lasting strategies that can maintain protective immune function over time are therefore a major unmet need. Stem-cell–based immune engineering offers a potential solution: by modifying hematopoietic stem and progenitor cells (HSPCs), it may be possible to create a renewable source of therapeutically programmed immune cells, enabling sustained immune modulation rather than transient effects. This concept builds on advances in gene therapy and immune engineering, where ex vivo modification of stem/progenitor cells can produce stable, long-term changes in immune cell populations.
Taken together, the rationale for this project is to leverage macrophage biology and immune-cell engineering to promote durable immunoregulation and tissue protection. By designing macrophages to adopt protective anti-inflammatory functions in response to disease-relevant immune activity, this strategy aims to reduce insulitis, preserve β-cell mass, and improve long-term glycemic stability. Overall, this approach seeks to develop an ex vivo lentiviral gene-modified CD34+ HSPCs that generates a durable progeny of engineered macrophages with tissue-reparative and anti-inflammatory functions for T1D pancreas
Description of Project
Type 1 Diabetes (T1D) is driven by an autoimmune response in which immune cells attack insulin producing beta cells in the pancreas. While insulin therapy is essential, it does not address the immune mechanisms that cause beta cell destruction. Thus, the major focus on T1D research is to develop approaches that reduce destructive pancreatic inflammation and help preserve beta cell numbers and function. Many immune-based strategies have shown promise, but durable benefit has been difficult to achieve because immune pathways can reactivate over time. New strategies are needed that are long-lasting and able to respond directly to disease-relevant immune activity.
This proposal focuses on macrophages, an innate immune subset that are abundant in pancreas during T1D development. Macrophages can contribute to disease by producing inflammatory mediators and supporting activation of autoreactive T cells (M1 macrophages). However, these cells can also adopt anti-inflammatory programs, support tissue repair and help restore immune balance (M2 macrophages). This ability to shift between inflammatory and reparative functions is often described as macrophage polarization. Increasing evidence suggests that promoting reparative macrophage behaviour in the pancreas could reduce local inflammation and improve beta cell survival. The central goal of this work is to engineer macrophages so that they become protective specifically when exposed to immune signals associated with T1D. Rather than broadly suppressing the immune system, we aim to create an immune programming that converts harmful autoimmune interactions into a signal that actively promotes anti-inflammatory macrophages within the pancreas. To achieve this, we will engineer a synthetic receptor called chimeric antigen receptor (CAR) using a lentiviral vector and deliver it into human CD34+ hematopoietic stem and progenitor cells (HSPCs). HSPCs are blood-forming cells that continuously generate immune cells, including monocytes and macrophages. By modifying HSPCs outside the body and transplanting them back, it is possible to create a durable source of engineered immune cells that self-renew and replenish. This stem cell-based strategy provides a platform for sustained immune modulation without requiring repeated administration of engineered cells. The CAR design is specialized for macrophage biology where engagement with T cells in the pancreas will trigger a signalling cascade that will promote macrophage reprogramming into M2 state. These M2 macrophages can reduce local tissue inflammation and secrete supportive factors that can improve survival of insulin-producing beta cells. We will perform in vitro and in vivo studies to evaluate pancreatic inflammation, macrophage polarization in the organ, preservation of beta cells and blood glucose control.
This project offers a path to establish a one time, durable, HSPC based CAR-Macrophage therapeutic intervention for T1D. By combining immune sensing with an anti-inflammatory signaling program, the approach is designed to reduce harmful pancreatic inflammation, preserve functional beta cell mass and improve long-term glucose stability.
Anticipated Outcome
This project is expected to establish a durable immune-engineering strategy that shifts inflammatory activity in the pancreas toward immune regulation and tissue protection in T1D. The primary anticipated outcome is the generation of therapeutically programmed macrophages that consistently adopt an anti-inflammatory, immunoregulatory phenotype in response to T1D autoimmune T cells. Measurable outcomes of key disease characteristics include reduced insulitis, preservation of insulin-producing β-cell mass, improved glycemic control.
Relevance to T1D
This project addresses a central unmet need in T1D – protecting insulin-producing β-cells. Preserving β-cell function is clinically important because partial endogenous insulin production is associated with improved glycemic stability and long-term metabolic outcomes. The therapeutic rationale is to shift the pancreatic immune environment from an inflammatory state to tissue protection that can preserve functional β-cell mass and stabilize metabolic control. A major advantage of the proposed approach is durability: a one-time, sustained intervention designed to maintain immune regulation over time and promote long-term disease stability. The potential for single administration treatment is particularly meaningful in T1D where daily disease management is intensive and durable therapeutic benefit could reduce the overall long-term treatment burden. Overall, this work develops a disease-modifying therapeutic approach for T1D.