Objective
The primary objective of this proposed study is to provide a proof-of-concept for a new approach that targets the production of the naturally occurring protein, CXCL12 (a molecule that supports and protects beta cells from the immune system), to the existing residual beta-cell mass and has the potential for translation to large animal models and clinical trials to treat and potentially cure T1D. We will use new Cationic Nanobubble (CNB) and Sonotransfection technology to achieve this. CNBs are tiny microscopic spheres that DNA sequences that code for specific proteins can be loaded onto. Sonotransfection on the other hand is a new way of making sure that the CNBs carrying DNA encoding CXCL12 get into cells in a specific organ like the pancreas. Several preclinical studies have established the feasibility of this approach involving the combination of CNBs, DNA and Sonotransfection as a means of targeting the incorporation of genes expressing proteins into pancreatic islet beta-cells. This objective involves the demonstration that we can robustly and reproducibly generate the combination product and then deliver therapeutically meaningful doses of DNA incorporated into so-called Nanoplasmids encoding CXCL12 (and under the control of a genetic sequence that makes sure the protein is only produced by beta-cells) into islets to safely and effectively reverse diabetes in a well-established mouse model of T1D.
The study also aims to bring a new young investigator into the field of T1D research - namely Dr. Fatma Dogan, a postdoctoral research fellow at the Vaccine and Immunotherapy Center, Massachusetts General Hospital and Harvard Medical School with significant interests in the delivery of genes encoding proteins that support and protect the residual beta cell mass in T1D.
The long-term objective of our proposal is to utilize an initial dataset generated from this study for interactions with the Food and Drug Administration (FDA) to identify the appropriate preclinical development pathway for our new combination product and enable the design of subsequent non human primate and subsequent first in human safety and subsequent efficacy studies.
The ultimate objective of our proposal is the development of a new treatment or potential cure for T1D which would apply to all individuals with the disease and that would restore the individual’s own functioning residual beta cell mass along with full islet function without the need for concurrent insulin therapy, continuous glucose monitoring, islet transplantation or systemic immune suppression with medications.
Background Rationale
Background and Rationale: Type 1 diabetes (T1D) results from the destruction of insulin-producing beta-cells in the pancreas by the immune system of the person with the disease. There is no cure for type 1 diabetes. Lifelong insulin replacement therapy can manage glucose levels in the blood to some extent but individuals with T1D require constant monitoring of their blood glucose levels to achieve this. While insulin pumps and glucose monitoring technologies are advances, they do not precisely imitate the control of natural insulin secretion by the pancreas. Replacement of beta-cells in the pancreas by transplantation of insulin-producing pancreatic islets offers an alternative and promising approach to cure T1D so that patients become free of insulin injections. However, the success of this approach is limited by the need for the chronic use of medications to suppress the immune system of the patient, called systemic immunosuppression and the lack of sufficient donor islets. Chronic systemic immunosuppression also predisposes patients to infection, organ damage, and cancer development.
In addition, and of importance to this proposal, it has been found that the immune system of the individual with T1D does not destroy all the beta-cells in the pancreas. There is a residual number of surviving insulin-producing beta-cells that is called the residual beta-cell mass. A critical limitation is that the residual beta cell mass in individuals with T1D does not produce enough insulin and is under potential attack from the person’s immune system. Therefore, the idea has arisen that the development of new strategies that potentially restore and protect this residual beta-cell mass could represent a new path to a cure for T1D.
We have been exploring the role of the naturally occurring protein in the body, called CXCL12, in regulating the immune system and supporting beta-cell growth and function. We and others have shown in multiple studies that CXCL12 supports the long-term survival of beta-cells while suppressing the immune response locally in the context of islet transplantation. In studies that we and others have performed, it has been shown that incorporation of CXCL12 into microscopic spheres of alginate containing transplanted mouse islets or human stem-cell derived islets supports long-term functional survival of beta-cells in healthy and diabetic mice and non-human primate (NHP) without the need for systemic immunosuppression, respectively. As a result of this, we now propose to explore whether we can direct beta-cells in islets of the residual beta-cell mass to selectively produce CXCL12 to see if it can support the survival, function and protect its function while protecting it from destruction by immune system in the individual with T1D. Thereby, avoiding the need for both islet transplantation or insulin therapy and glucose monitoring. The overall idea here is that if the beta-cell mass could be restored and protected from the immune system in the individual with T1D this approach could ultimately reverse the diabetic state and maintain blood glucose in a natural way that resembles glucose control in a person without diabetes. Our proposal sets out to develop a new combination therapy that delivers CXCL12 specifically to islets in diabetes, and test it in the first instance in a mouse model of T1D that resembles the human disease and see whether we can sustainedly reverse diabetes in this setting using this new approach.
Description of Project
Background and limitation of current therapies: Type 1 diabetes (T1D) results from the destruction of insulin producing beta-cells in the pancreas by the immune system of the person with the disease. There is no cure for T1D. Lifelong insulin replacement therapy can manage glucose levels in the blood but individuals with T1D require constant monitoring. While insulin pumps and continuous glucose monitoring technologies are advances, they do not precisely recapitulate natural insulin secretion by the pancreas.
Replacement of insulin producing beta-cells by transplantation of insulin-producing pancreatic islets where beta-cells are found, is a promising approach to cure T1D. However, the success of this approach is limited by the need for the chronic use of medications to suppress the immune system of the patient, called systemic immunosuppression. Chronic systemic immunosuppression predisposes patients to infection, organ damage, and cancer. Of importance to this proposal is that it has been found that the immune system of individuals with T1D do not infact destroy all the beta-cells in the pancreas. In some individuals with T1D there is a residual number of surviving insulin-producing beta-cells. Therefore, the development of new clinically relevant treatments that restore and protect those residual beta-cells from the individuals immune system could represent a new path to a cure for T1D.
Preliminary Studies: We have been exploring the role of the naturally occurring protein in the body, called CXCL12, in regulating the immune system and supporting beta-cell growth and function. We have shown that CXCL12 supports long-term survival of beta-cells while suppressing the immune response locally in the context of islet transplantation. In our studies, incorporation of CXCL12 into alginate microcapsules containing transplanted mouse islets or human stem-cell derived islets supports long-term functional survival in diabetic mice and non-human primates (NHPs) without systemic immunosuppression. As a result of this we propose to explore whether we can direct CXCL12 to support the survival, function and immune-protection of the residual beta-cell mass in T1D, avoiding the need for islet transplantation and systemic immunosuppression.
Research Plan: In this study, we propose to develop and optimize a safe, effective and clinically-relevant method for delivering CXCL12 to the residual beta-cell mass and see whether this can reverse the diabetic state in a mouse model of T1D that closely resembles the human disease. We will combine specific advanced technologies to achieve this including NanoplasmidsTM (a way of encoding CXCL12 and having it expressed selectively in islets) and sonotransfection technology (a way of getting the CXCL12 NanoplasmidsTM into cells) to enable beta-cells to express this protein long-term at a level that is capable of reversing the progression of diabetes and restoring normal blood glucose levels. The proposed research will be assiduously managed and completed in 2 ½ years in a collaborative effort involving the PI’s lab at Massachusetts General Hospital (CXCL12 gene transfer and islet biology/transplantation expertise), Dr. Exner’s laboratory at Case Western Reserve University and Dr. Benninger’s laboratory at the University of Colorado (nanobubble/sonotransfection expertise).
Outcomes of Research and Impact for T1D: If successful this collaborative project will provide a proof-of-concept to fellow scientists for a new approach that targets CXCL12 to the residual beta-cell mass and has the potential for translation to large animal models and clinical trials to treat and potentially cure T1D. The short-term development goals for this project are to demonstrate the approach has the capability of delivering therapeutically meaningful doses of Nanoplasmids encoding CXCL12 into islets to improve disease reversal in an established mouse model of T1D. Long-term goals are to use these initial data for interactions with the FDA and to identify the preclinical development pathway to NHP and human studies.
Anticipated Outcome
The anticipated outcomes of this study will be
1. The demonstration that two technologies (a DNA construct called a nanoplasmid and encoding CXCL12 for immune protection and support of beta-cells along with sonotransfection of the DNA encoding the CXCL12 specifically into beta cells so that they express the protein) can be successfully and safely brought together and work in the context of mouse and human islets in the test tube (in vitro) and mouse islets in a well-established mouse model of type 1 diabetes (T1D) in mice (in vivo).
2. The demonstration that the combination of these two technologies can result in durable (up to 180 days) reversal of diabetes in a well-established mouse model of T1D without the need for additional injections of insulin or any medication that suppresses the immune system throughout the entire body.
3. That the effect of the combination approach can be demonstrated independently in a second laboratory in order to underline the reproducibility of the study. This is important when considering moving the technology towards more advanced animal testing and subsequently to testing in individuals with T1D.
4. That a dataset is generated from this study that could be used to support a preclinical development plan that proposes to take the technology forward to regulatory review by the U.S. Food and Drug Administration.
5. Successful demonstration of a close scientific collaboration between three different laboratories and their scientists with different but synergistic expertise at the Vaccine and Immunotherapy Center, Massachusetts General Hospital, Harvard Medical School, Case Western Reserve University and the University of Colorado.
6. Execution of the project to carefully managed timelines and costs by an expert project manager with broad experience of executing on complex multi-institutional collaborative research plans.
Relevance to T1D
If successful this collaborative project between scientists at three medical research centers in the USA will provide a proof-of-concept for a new approach that targets the naturally occurring immune protective and beta-cell supportive protein, CXCL12, to the residual insulin producing beta-cell mass in Type 1 Diabetes (T1D). This new approach has the potential for translation to large animal models and clinical trials to treat and potentially cure T1D. The short-term goals for this project are to optimize the production of a new combination product involving DNA nanoplasmids encoding CXCL12 and its delivery specifically to beta-cells using so called nanobubbles and sonotransfection that help to get the gene into beta-cells. We propose to demonstrate that this approach has the capability of delivering therapeutically meaningful doses of nanoplasmids that encode CXCL12 specifically into islets that result in reversal of T1D and the establishment of normal blood glucose levels without the use of additional injected insulin in a well-established mouse model of T1D that resembles the human disease. In the first instance, this finding would only be relevant to scientists who are exploring new approaches to treating and curing T1D. However, in the long-term, the potential would be to utilize the results of this study to inform the further testing of this technology in large animal models of T1D. Beyond this data generated from these studies would guide conversations with the Federal Agency that allows new treatments and cures for T1D to proceed toward the study of the safety and efficacy of this new approach in studies in humans with the disease.