Objective
The objective of this research project is to dissect the function of three new biomarkers (miR-103, miR-122, and miR-192) that belong to a family of small RNA molecules, termed microRNAs, which can regulate the expression of specific genes during SC differentiation and maturation into islet cells.
Specifically, we aim to test the function of these three microRNAs by producing new SC lines in which we can induce the production of these molecules.
Our expectation is that this intervention will augment the yield of islet cells from SC, and accelerate their functional maturation into glucose-responsive insulin-producing islet beta-cells.
In summary, our goal is to improve the process of turning SCs into insulin-producing cells by increasing the production of novel microRNAs that we recently discovered to be associated with SC propensity to become pancreatic islet cells. This line of work may significantly improve our ability to produce functional islet tissue for transplantation in T1D.
Background Rationale
Stem cell (SC)-based replacement therapy is emerging as a promising cure for type 1 diabetes (T1D). However, the population-wide applicability of this approach remains constrained by the limited efficiency of current protocols to resolve the state of pluripotency of different SC lines through morphogens and inductive factors, due to multiple “bottlenecks” that SCs have to overcome before acquiring an islet-like phenotype. Hence, even after lengthy screenings to identify SC clones with the highest developmental propensity to differentiate into islet cells, -like cells resulting from these procedures may still be either short-lived poly-hormonal cells, held at progenitor-like stages, or functionally immature. Therefore, there is a pressing need to develop more efficient strategies of stem cell differentiation toward pancreatic islet cells, which are ideally also applicable to induced pluripotent stem cells (iPSCs) for the development of patient-tailored cell replacement therapies.
Recent work from our laboratory has identified an important mechanism of cell-cell communication that fosters a more efficient differentiation of multiple SC lines into Definitive Endoderm and Endocrine Progenitor lineages, leading to a more homogeneous differentiation into islet cell populations.
Hence, the overarching goal of this proposal is to identify novel drivers of SC commitment and differentiation into functional islet cells. Specifically, we will focus on the regulatory role of select microRNAs (miRNAs), which our preliminary work has identified as significant downstream effectors of gap junction (GJ)-mediated cell-to-cell communication at select stages of SC differentiation (see Preliminary Data). Collectively, this research will fill a knowledge gap on molecular mechanisms governing SC differentiation into islet tissue and ultimately broaden the therapeutic potential and applicability of SC-based treatments across multiple SC lines, thus advancing strategies of cell replacement therapies for T1D.
Description of Project
Stem cell (SC)-based replacement therapy is emerging as promising cure for Type 1 diabetes. However, despite recent advances and promising results from pilot clinical trials, there are challenges with current methods for the production of large quantities of insulin-secreting cells from SC. These challenges include the variability among different SC lines in controlling their propensity to become the specific cell types needed for treating diabetes. As a results, current protocols often produce cell preparation that contain a mixture of different types of cells, some of which may not be fully developed or functional. We have recently discovered that by augmenting cell-cell communication in SC during their differentiation, we can promote a more efficient derivation of pancreatic islet progenitors from SCs. As part of these studies, we discovered that augmenting cell-cell communication in SC, increases the production of three new biomarkers (miR-103, miR-122, and miR-192) that belong to a family of small RNA molecules, termed microRNAs, which can regulate the expression of specific genes during SC differentiation and maturation into islet cells. In this project, we aim to focus on the specific function of these three microRNAs by producing new SC lines in which we can induce and increase the production of these molecules. Our expectation is that this intervention will augment the yield of islet cells from SC, and accelerate their functional maturation into glucose-responsive insulin-producing islet beta-cells.
In summary, this project aims to improve the process of turning SCs into insulin-producing cells by increasing the production of novel microRNAs that we recently discovered to be associated with SC propensity to become pancreatic islet cells. This line of work may significantly improve our ability to produce functional islet tissue for transplantation in T1D.
Anticipated Outcome
We anticipate that results from the proposed work will significantly enhance the ability to produce functional islet tissue from multiple SC lines. Specifically, we expect to identify new gene targets that are controlled by the microRNAs. Hence, by testing the effect of inducing the production of these molecules in SC during their differentiation into islet cells, we will be able to identify new biomarkers that can be targeted to improve current protocols of islet tissue derivation from SCs.
In addition, our studies are also likely to identify new genes and regulatory biomarkers that can accelerate the functional maturation of SC-derived islet tissue, ultimately contributing to advance the implementation of SC therapy to a much larger demographic of patients with T1D.
Relevance to T1D
Despite recent promising results from pilot clinical trials, the large demographic use of SC-derived islet tissue to cure T1D faces several bottlenecks. These include the limited efficiency of current protocols to resolve the state of pluripotency of different SC lines and promote their efficient differentiation into islet tissue.
Therefore, there is a pressing need to develop more efficient strategies of stem cell differentiation to produce large numbers of functional islet cells.
Our laboratory has recently identified an important mechanism of cell-cell communication that fosters a more efficient differentiation of multiple SC lines. This process led us to discover new molecule, termed microRNAs that are produced during the conversion of pluripotent SCs into islet cells.
The research proposed in this project will identify the mechanisms that govern SC decision to become islet cells, and contribute to improving the process of islet tissue production from SCs, thus expanding the use of cell replacement therapies to cure T1D.