Objective
Our study aims to investigate the role of a molecule called soluble (s)PD-1 in the development of type 1 diabetes (T1D). Our hypothesis is that high levels in the blood of sPD-1 may contribute to the excessive activation of the immune system, which in turn leads to the progression of T1D.
To test this hypothesis, we will conduct experiments using both human and mouse models of T1D to examine the molecular and functional effects of sPD-1 during different stages of disease progression.
Our research proposal has three specific objectives:
Aim 1: We will analyze the levels of both membrane-bound and soluble forms of PD-1 in fresh human immune T cells, as well as upon their activation by a specific receptor. We will investigate the association between these forms of PD-1 and the functions of the pancreas. This will help us understand how sPD-1 is involved in T1D progression.
Aim 2: We will silence the expression of sPD-1 in immune T cells in a laboratory setting and observe the effects on T cell activation during T1D progression. This will give us insights into the specific role of sPD-1 in regulating T cell activity in the context of the disease.
Aim 3: We will conduct experiments in a specific mouse model for studying T1D. We will treat these mice with a molecule that mimics sPD1 and another molecule that mimics its ligand PD-L1. By doing this, we aim to control the development of T1D in these mice and understand the impact of modulating the PD-1 pathway on the disease progression.
By conducting these experiments, we hope to gain a deeper understanding of the role of sPD-1 in autoimmune diabetes. This knowledge may lead to new insights and potential therapeutic strategies for preventing and treating T1D.
Background Rationale
It has well known that genetic factors and environmental triggers can lead to the development of type 1 diabetes (T1D) by causing the immune system to attack the pancreas. This immune response gradually damages the insulin-producing cells in the pancreas, even before symptoms of T1D become apparent. Researchers have identified specific markers, called islet-autoantibodies, that indicate the progression of T1D. These markers can help track the disease's development but do not directly cause damage to the pancreatic cells. The actual damage is caused by specific types of immune cells called CD4+ and CD8+ T lymphocytes. The immune system normally has regulatory pathways in place to maintain self-tolerance and prevent harmful attacks on the body's own tissues. However, defects in these regulatory pathways can lead to an imbalance and contribute to the development of T1D. One crucial aspect of immune regulation involves several molecules to maintain immune homeostasis; among them, there are the “immune checkpoint molecules” (ICM)., including the programmed death-1 (PD-1) and its ligands (PD-L1 and PD-L2). PD-1 controls the activation of T cells and the production of certain immune molecules by interacting with its ligand on certain cells called antigen-presenting cells. There are different forms of PD-1, including a soluble form called sPD-1, which can interfere with the normal functioning of the membrane form of PD-1 promoting T cell activation. The PD-1 pathway is involved in various autoimmune diseases, including T1D. Studies on mice and humans have shown that reduced expression of PD-1 contributes to the development of T1D. Additionally, it was observed that treatment with PD-1-blocking drugs in cancer patients with T1D genetic predisposition leads to the development of autoimmune diabetes; these findings highlight the importance of the PD-1/PD-L1 pathway in maintaining immune tolerance towards the pancreas. Also, our recent research suggests that high levels of sPD-1 are altered in T1D children and also in the preclinical stages of the disease. This suggests that sPD-1 may play a role in the progression of autoimmune diabetes. Further investigation is needed to fully understand the function and clinical significance of sPD-1 in T1D.
Description of Project
Type 1 diabetes (T1D) is an autoimmune disease that occurs when the immune system mistakenly attacks the cells in the pancreas that produce insulin. This disorder follows a series of stages before it becomes clinically apparent in affected individuals. While scientists have made progress in understanding the immune changes associated with T1D, the exact mechanisms responsible for its development are not fully understood.
Our immune system has various ways to regulate itself and prevent autoimmune diseases. One such regulatory mechanism involves specific immunological molecules, called immune checkpoint molecules (ICM) which help control immune responses.
A specific ICM known as programmed death-1 (PD-1) plays a crucial role in the control of the responses of the immune system. This molecule was initially identified on the surface of immune cells, but recent studies have also found a soluble form (sPD-1), which has not been explored in detail in T1D pathogenesis.
In our previous research, we discovered elevated sPD-1 levels in the blood of individuals with T1D; furthermore, our recent longitudinal study revealed that children at risk to develop T1D disease displayed high circulating levels of this molecule, strongly associated with the subsequent progression to T1D.
In this current research, we aim to investigate the role of sPD-1, its effects on the immune system, and the contribution to T1D development. Understanding these mechanisms could lead to new treatments to prevent autoimmune diabetes.
Anticipated Outcome
The outcomes of our research may provide valuable insights into the role of soluble PD-1 in autoimmune diabetes, particularly in the context of T1D.
First, analysis of the blood levels of membrane-bound and soluble forms of PD-1 in human immune T cells leads us to understand how these forms are associated with the pancreas function giving us insights into the role of soluble (s)PD-1 in the progression of type 1 diabetes (T1D). If our hypothesis is correct, we may find that increased levels of sPD-1 are linked to the activation of T cells and the destruction of pancreatic cells, contributing to the development and progression of T1D.
Second, the silencing of sPD-1 in immune T cells in our laboratory experiments will help us determine the specific effects of sPD-1 on T cell activation during T1D progression. If our hypothesis is supported, we may observe that reducing soluble PD-1 levels leads to a decrease in T cell activation. This could suggest that targeting sPD-1 could be a viable approach for controlling the disease.
Finally, the treatment of T1D mice with the mimic sPD1 and PD-L1 molecules aims to modulate the PD-1 pathway and observe the effects on T1D development. If our hypothesis holds true, we might find that these treatments can effectively control the development of T1D in mice. This outcome could pave the way for future human studies to develop targeted sPD-1 treatments for preventing T1D.
Overall, these findings could potentially lead to new therapeutic approaches and strategies for managing and treating T1D, ultimately improving the lives of individuals affected by this condition.
Relevance to T1D
Our goal is to investigate the effects of high levels of a molecule called soluble (s)PD-1 during the various stages of T1D progression. While the role of PD-1 at the cell surface has been extensively studied, the specific contribution of sPD-1 to T1D pathogenesis remains largely unexplored.
We believe that this molecule plays a crucial role in sustaining the hyperactivation of T cells, leading to the loss of self-tolerance in the pancreas and the development of T1D.
By studying the effects of sPD-1 during different stages of T1D progression, this research aims to uncover important insights into the underlying mechanisms of the disease. It seeks to answer questions about how T cells become hyperactivated and how the immune system loses tolerance towards pancreatic cells.
Ultimately, the relevance of this research lies in its potential to halt T1D development. By deepening our understanding of the disease, this research may contribute to specific soluble PD-1 interventions that can slow down or even halt the progression of T1D. Such advancements have the potential to significantly enhance the quality of life for individuals living with this chronic condition.
In summary, this research is highly relevant for T1D as it strives to unravel the molecular mechanisms of disease progression, exploring sPD1 as a novel immune target for preventing or managing T1D.