Objective
The overall objective of this research proposal is to evaluate the therapeutic potential of SEC24A inhibition for the treatment of Type 1 diabetes (T1D). SEC24A plays a critical role in cellular stress relief, protein processing, and transport. To achieve this goal, the research will be divided into two aims: (1) Defining the role of SEC24A in human beta cells by generating SEC24A-deleted beta cell lines from an immortalized human beta cell line and T1D individual's stem cell-derived beta cells, and using these cell lines to examine how human beta cells adapt to cellular stress conditions in response to the SEC24A deletion. (2) Determining the capability of SEC24A inhibition in beta cell autoimmune protection by designing a series of experiments to understand how SEC24A genetic deletion affects the interaction between beta cells and immune cells. Additionally, we will examine a recently-identified SEC24A chemical inhibitor for beta cell preservation under autoimmune attack and diabetes prevention using T1D animal models. Together, these aims will establish a comprehensive view of SEC24A functional inhibition in protecting beta cells against cellular stress and immune-mediated destruction.
Background Rationale
T1D is a chronic autoimmune disease in which the immune system specifically targets and destroys the insulin-producing beta cells in the pancreatic specialized structure, the islets. The loss of beta cells leads to insulin insufficiency and subsequently uncontrollable high blood sugar levels, resulting in the occurrence of autoimmune diabetes. When self-reactive immune cells launch their attack, beta cells become stressed, dysfunctional, and ultimately die. Stress signals in beta cells have been implicated as a potential cause of T1D due to triggering cell death pathways and promoting cell visibility to immune cells. Self-reactive immune cells "see" beta cells through the cell membrane antigen presentation, followed by their activity of immune destruction. Antigens are a small fraction of an intact protein presented by the beta cell membrane surface protein, major histocompatibility complex class I (MHC I). Beta cells are well known for their vulnerability by upregulating their MHCI expression under stress conditions. Therefore, liberating beta cells from stress conditions may be an alternative strategy to tackle autoimmune diabetes. Our approach is to apply the state-of-the-art technology, CRISPR-Cas9, to search for genes that make beta cells withstand cellular stress. We found that beta cells without SEC24A expression were resistant to stress-induced cell death and delayed autoimmune killing. In this research proposal, we will characterize the functional role of SEC24A in regulating beta cell vulnerability and how this gene deletion protects beta cells against stress-induced cell death and autoimmunity.
Description of Project
Type 1 diabetes (T1D), also known as autoimmune diabetes, is a condition in which the body's immune system destroys the insulin-producing pancreatic beta cells, resulting in insulin insufficiency and high blood sugar levels. Individuals living with T1D rely on multiple daily insulin injections for survival for the rest of their lives. Recent studies have found that beta cells reduce their defense ability against autoimmunity when under stress conditions. To further understand how beta cells are affected by stress signals, this research proposal uses cutting-edge genomic editing technology, CRISPR-Cas9, to search for genes that can protect beta cells from a cellular stress condition called endoplasmic reticulum (ER) stress. We found that deleting a gene named SEC24A in beta cells makes beta cells sustain the stress- and inflammation-induced cell death. This research proposal will use a thorough plan to characterize and understand why this loss of SEC24A strengthens beta cells' capability to combat stress conditions and autoimmune attack. The research results will deliver the possibility of SEC24A functional inhibition for developing new T1D therapeutic strategies.
Anticipated Outcome
This research proposal aims to deliver a potential therapeutic strategy for Type 1 diabetes (T1D) by inducing beta cell autoimmune tolerance. By utilizing cutting-edge technology, the proposed research aims to identify a previously unappreciated role of SEC24A in controlling beta cell antigen presentation, stress response, and T1D development. The research will further generate new concepts and knowledge on beta cell protection against autoimmunity, including the role of SEC24A as a key player in the ER protein transport machinery, and its potential as a chemical inhibitor for beta cell protection and T1D prevention. The research design will validate the functional role of SEC24A in human beta cells, providing fundamental knowledge to understanding SEC24A-mediated protein transport and its impact on cell immune visibility and insulin release. The expected outcome of this research is to leverage future funding opportunities and extend the information collected from the current project, with the ultimate goal of advancing current T1D therapeutic strategies through SEC24A inhibition and providing a proof-of-concept for further preclinical investigation.
Relevance to T1D
Type 1 diabetes (T1D) is a lifelong disease that requires multiple daily insulin injections for managing blood sugar levels. With approximately 1.6 million Americans living with T1D and projections of 5 million Americans to be diagnosed by 2050, there is a pressing need for new T1D therapy. A pathological hallmark of T1D is islet inflammation, which leads to the accumulation of intracellular stress in insulin-producing beta cells and ultimately causes cell dysfunction and death. This proposal aims to use CRISPR-Cas9 technology to identify genes that protect beta cells against cellular stress and investigate new mechanisms of beta cell stress adaptation and relief. The ultimate goal is to develop a potential T1D treatment that advances current therapeutic strategies and ultimately leads to a cure.