Biology subjects

Hogrebe, N. J.

Publications and source records attributed to Hogrebe, N. J..

2 recordsLinked to original sources

bioRxiv2024

Controlling human stem cell-derived islet composition using magnetic sorting

Stem cell-derived islets (SC-islets) consists of multiple hormone-producing cell types and offer a promising therapeutic avenue for treating type 1 diabetes (T1D). Currently, the composition of cell types generated within these SC-islets currently cannot be controlled via soluble factors during this differentiation process and consist of off-target cell types. In this study, we devised a magnetic-activated cell sorting (MACS) protocol to enrich SC-islets for CD49a, a marker associated with functional insulin-producing {beta} cells. SC-islets were generated from human pluripotent stem cells (hPSCs) using an adherent differentiation protocol and then sorted and aggregated into islet-like clusters to produce CD49a-enriched, CD49a-depleted, and unsorted SC-islets. Single-cell RNA sequencing (scRNA-seq) and immunostaining revealed that CD49a-enriched SC-islets had higher proportions of {beta} cells and improved transcriptional identity compared to other cell types. Functional assays demonstrated that CD49a-enriched SC-islets exhibited enhanced glucose-stimulated insulin secretion both in vitro and in vivo following transplantation into diabetic mice. These findings suggest that CD49a-based sorting significantly improves {beta} cell identity and the overall function of SC-islets, improving their effectiveness for T1D cell replacement therapies.

bioengineering↗

bioRxiv2024

Depolymerizing F-actin accelerates the exit from pluripotency to enhance stem cell-derived islet differentiation

In this study, we demonstrate that cytoskeletal state at the onset of directed differentiation is critical for the specification of human pluripotent stem cells (hPSCs) to all three germ layers. In particular, a polymerized actin cytoskeleton facilitates directed ectoderm differentiation, while depolymerizing F-actin promotes mesendoderm lineages. Applying this concept to a stem cell-derived islet (SC-islet) differentiation protocol, we show that depolymerizing F-actin with latrunculin A (latA) during the first 24 hours of definitive endoderm formation facilitates rapid exit from pluripotency and alters Activin/Nodal, BMP, JNK-JUN, and WNT pathway signaling dynamics. These signaling changes influence downstream patterning of the gut tube, leading to improved pancreatic progenitor identity and decreased expression of markers associated with other endodermal lineages. Continued differentiation generates islets containing a higher percentage of {beta} cells that exhibit improved maturation, insulin secretion, and ability to reverse hyperglycemia. Furthermore, this latA treatment reduces enterochromaffin cells in the final cell population and corrects differentiations from hPSC lines that otherwise fail to consistently produce pancreatic islets, highlighting the importance of cytoskeletal signaling at the onset of directed differentiation.

cell biology↗