Beta-cells 1st Responders and Functional Paracrine Networks in Healthy and Diabetic Human Islets
Contact PI: Vira Kravets PhD, University of Colorado, Denver
Start Date: March 2021
Beta cell heterogeneity and impact of small subset of beta cells onto the rest of the islet’s beta cell population in the intact islets have been recently studied from the point of view of genetics, molecular composition, and functional differences (ion channel function, calcium dynamics). However, whether discovered beta cell subpopulations overlap, whether they are stable in time, and whether subpopulations discovered in rodents exist in human islets is unknown due to following barriers in the field: lack of simultaneous tracking of multiple cells activity in the intact islet; lack of in-situ models, like the recently developed human pancreatic acute tissue slices; lack of targeted interrogation of a single cell in the intact islet; lack of a standards for cell activity synchronization analysis. In my project I propose following solutions to these barriers. 1. Use of high-resolution confocal microscopy in 3D, allowing [Ca2+] visualization in all endocrine cells. 2. I will use acute human pancreatic slices from healthy and diabetic donors, shipped to us by nPOD program or prepare them in house (a procedure which I have already established in the lab). 3. I will use phenotype-based targeted removal of a single cell from the islet via 2-photon laser ablation. 4. I will use an algorithm for [Ca2+] coordination network analysis, obtained through collaboration with the author of one of the latest b-cell heterogeneity papers, David Hodson. In this way, we will not only describe the 1st responder b -cell subpopulations which may be disproportionately affecting islet function in vivo, but will also assess how they overlap with the “hub” cell subpopulations, lately raising much debate in the field.
Mapping the response time of b-cells to glucose stimulation in human islets, and investigating functional network connectivity, in addition to what I have done in mice, will allow for the teasing-out of the relative roles of paracrine a-b-cell and d-b-cell interactions vs b-b-cell electrical coupling in the functional heterogeneity of b-cells. It will also allow for the translation of this study towards the search for therapies to boost islet response to glucose in diabetic conditions.