The incidence of diabetes mellitus has reached epidemic proportions in the U.S. and will continue to increase rapidly across all age group and ethnicities for the foreseeable future. The resulting cost to society via health care, lost wages, etc. is staggering and the decreased quality of life is immeasurable. Type 2 diabetes is primarily manifest in two categories, insufficient insulin secretion and enhanced insulin resistance. In non-diabetics, increased serum glucose stimulates insulin secretion from the pancreatic ?-cell and decreases glucagon secretion from the pancreatic ?-cell. Glucose-stimulated insulin secretion is a complex process that is regulated via complex signaling pathways within the cell. The dynamics of cellular signaling, and corresponding insulin release, are critical to normal regulation of serum glucose, however, detection of many cellular signals is not possible due to a dearth of sensing technologies. Recent studies have rediscovered the importance of the ?-cell in regulating serum glucose, however much less is understood regarding the dynamics of metabolic signaling in ?-cells. A better understanding of intracellular signaling and corresponding regulated release within both of these cell types is of paramount importance to elucidate the root causes of secretory abnormalities and the corresponding roles in the onset and progression of diabetes. The primary focus of this proposal is to develop suitable capabilities to monitor metabolic and carbohydrate-derived signals in ?- and ?-cells, and to facilitate identification of key molecular differences that may contribute to diabetes. We will develop, characterize and utilize a highly-stable, porous phospholipid architecture with enhanced mass transport capabilities for detection of intracellular regulators that lack intrinsic optical or electrochemical activity. Phospholipid scaffolds are prepared with ca. 5 nm thick polymerized phospholipid membranes into which size selective pores are introduced. The porous membranes are analogous to dialysis membranes and are highly permeable to small molecules irrespective of charge but retain/exclude large molecular weight species. This architecture will allow novel enzymatic and fluorescent reporter chemistries to be used for intracellular measurements of heretofore undetectable analytes. We will optimize the formation of porous membranes via investigation of novel polymer stabilization schemes, devise strategies to deliver bioavailable sensors into the cell and utilize sensors designed for pyruvate, ATP, K+, glucose and inositol hexakisphosphate, key ?-cell signals whose roles are less defined in the ?-cell, to investigate metabolic signaling dynamics in these two important cell types. Onc fully-developed, porous lipid architectures may prove valuable for a host of other applications including large molecule drug delivery, etc.
This research project will lead to development of a new category of nanometer-sized chemical and biological sensors that are compatible with the intracellular environment. These sensors will enable new questions to be asked and answered in the area of signal transduction in important neuroendocrine cells and will enable new hypotheses to be tested in the role of metabolic coupling in pancreatic alpha cells and a range of other cellular systems involved in the regulation of normal human health.
| Janczak, Colleen M; Calderon, Isen A C; Mokhtari, Zeinab et al. (2018) Polystyrene-Core, Silica-Shell Scintillant Nanoparticles for Low-Energy Radionuclide Quantification in Aqueous Media. ACS Appl Mater Interfaces 10:4953-4960 |
| Ghosh, Surajit; Wang, Xuemin; Wang, Jinyan et al. (2018) Enhanced Fluorescent Protein Activity in Polymer Scaffold-Stabilized Phospholipid Nanoshells Using Neutral Redox Initiator Polymerization Conditions. ACS Omega 3:15890-15899 |
