Basic Biology IV
$1 414 044
Replacement of tissues and organs with multipotent stem cell sources has been the focus of intensive investigations. Absolute or relative deficiency of insulin-producing pancreatic β-cells underlies both type 1 and type 2 diabetes mellitus. Despite considerable recent progress, many fundamental issues related to the specialization and functional maturation of replacement β-cells from sources like human embryonic stem cells or induced pluripotent stem cells remain to be resolved. Our goal is to exploit novel mechanisms and pathways, discovered through our prior studies of native mouse and human β-cell development, to drive maturation of functional replacement β-cells produced from cultured human ES and iPS cells. Our proposals aims are: (1) Identify endogenous signaling pathways that stimulate functional maturation of Insulin-secreting cells produced from human ES or iPS cells. (2) Identify small molecules through candidate screens that control and enhance β-cell maturation. (3) Use new chemical-genetic methods to stimulate electrical activity and provoke maturation of Insulin-secreting cells. Successful completion of milestones in our proposal should accelerate attainment of our goal to produce functional replacement β-cells from human ES and iPS cells that are indistinguishable from native pancreatic islet β-cells.
Statement of Benefit to California:
Diabetes mellitus is a terrible disease afflicting millions worldwide, including citizens of California. Our studies address a root cause of the major forms of diabetes and propose to generate strategies to regenerate or replace pancreatic beta-cells, the source of the hormone insulin which is deficient in diabetes. Our studies target cell pathways and molecular mechanisms discovered from prior studies by our laboratory. These pathways and mechanisms regulate growth, development and maturation of many vital organs, including the heart, brain, bone, and pancreas. Thus, results and experience gained from completion of studies proposed here could greatly accelerate progress in generating replacement cells for multiple tissues and organs relevant to the CIRM mission.
The goal of this proposal is to develop methods for producing mature and functional pancreatic beta cells from human embryonic and induced pluripotent stem cells (hESC and hiPSC) by exploiting knowledge discovered from studies of native mouse and human beta cell development. To achieve these ends, the applicant proposes three aims encompassing 1) the identification of endogenous signaling pathways that stimulate functional maturation of insulin-secreting beta cells derived from hESC or hiPSC; 2) the discovery of small factors that control and enhance beta cell maturation; and 3) the application of new chemical-genetic methods to stimulate electrical activity in insulin-secreting cells and provoke their maturation. Significance and Innovation - Reviewers raised major concerns about the underlying rationale of this proposal. There was insufficient experimental evidence to convince them that the molecular pathway proposed for study is critical for beta cell maturation, and a previously published finding cast serious doubt on this assumption. - Successful production of mature, functional beta cells from pluripotent stem cells would represent a significant step forward in regenerative medicine and could pave the way for treating and potentially curing diabetes. - The use of optogenetic approaches in the context of beta cell maturation is innovative, even if unlikely to be practical for clinical translation. Feasibility and Experimental Design - While experiments are well designed and feasible, there is little consideration of potential pitfalls or alternative approaches. - The cell populations described and assessed in the preliminary data are of uncertain relevance to the cell types derived from hESC or hiPSC. - The proposed studies are achievable within the given timeline. Principal Investigator (PI) and Research Team - The PI is an exceptional scientist who has made a number of important contributions in the developmental biology of the endocrine pancreas. Expertise in hESC and hiPSC is less well established. Responsiveness to the RFA - The proposed effort is responsive in that it utilizes human stem cells and seeks to identify molecular determinants of cell fate.