A Peninsular Structure Coordinates Asynchronous Differentiation with Morphogenesis to Generate Pancreatic Islets.

The pancreatic islets of Langerhans regulate glucose homeostasis. The loss of insulin-producing ß cells within islets results in diabetes, and islet transplantation from cadaveric donors can cure the disease. In vitro production of whole islets, not just ß cells, will benefit from a better understanding of endocrine differentiation and islet morphogenesis. We used single-cell mRNA sequencing to obtain a detailed description of pancreatic islet development. Contrary to the prevailing dogma, we find islet morphology and endocrine differentiation to be directly related. As endocrine progenitors differentiate, they migrate in cohesion and form bud-like islet precursors, or "peninsulas" (literally "almost islands"). α cells, the first to develop, constitute the peninsular outer layer, and ß cells form later, beneath them. This spatiotemporal collinearity leads to the typical core-mantle architecture of the mature, spherical islet. Finally, we induce peninsula-like structures in differentiating human embryonic stem cells, laying the ground for the generation of entire islets in vitro.

Rapid exponential increase in neurosurgery departmental scholarly output following an intensive research initiative.

There has been extensive research into methods of increasing academic departmental scholarly activity (DSA) through targeted interventions. Residency programmes are responsible for ensuring sufficient scholarly opportunities for residents. We sought to discover the outcomes of an intensive research initiative (IRI) on DSA in our department in a short-time interval. IRI was implemented, consisting of multiple interventions, to rapidly produce an increase in DSA through resident/medical student faculty engagement. We compare pre-IRI (8 years) and post-IRI (2 years) research products (RP), defined as the sum of oral presentations and publications, to evaluate the IRI. The study was performed in 2020. The IRI resulted in an exponential increase in DSA with an annual RP increase of 350% from 2017 (3 RP) to 2018 (14 RP), with another 92% from 2018 (14 RP) to 2019 (27 RP). RP/year exponentially increased from 2.1/year to 10.5/year for residents and 0.5/year to 10/year for medical students, resulting in a 400% and 1900% increase in RP/year, respectively. The common methods in literature to increase DSA included instituting protected research time (23.8%) and research curriculum (21.5%). We share our department's increase in DSA over a short 2-year period after implementing our IRI. Our goal in reporting our experience is to provide an example for departments that need to rapidly increase their DSA. By reporting the shortest time interval to achieve exponential DSA growth, we hope this example can support programmes in petitioning hospitals and medical colleges for academic support resources.

Wnt Signaling Separates the Progenitor and Endocrine Compartments during Pancreas Development.

In vitro differentiation of pluripotent cells into ß cells is a promising alternative to cadaveric-islet transplantation as a cure for type 1 diabetes (T1D). During the directed differentiation of human embryonic stem cells (hESCS) by exogenous factors, numerous genes that affect the differentiation process are turned on and off autonomously. Manipulating these reactions could increase the efficiency of differentiation and provide a more complete control over the final composition of cell populations. To uncover in vitro autonomous responses, we performed single-cell RNA sequencing on hESCs as they differentiate in spherical clusters. We observed that endocrine cells and their progenitors exist beside one another in separate compartments that activate distinct genetic pathways. WNT pathway inhibition in the endocrine domain of the differentiating clusters reveals a necessary role for the WNT inhibitor APC during islet formation in vivo. Accordingly, WNT inhibition in vitro causes an increase in the proportion of differentiated endocrine cells.

Fission yeast-based high-throughput screens for PKA pathway inhibitors and activators.

Features of the fission yeast Schizosaccharomyces pombe cAMP/PKA pathway make S. pombe particularly amenable for heterologous expression of cAMP pathway proteins such as GαS subunits and their cognate adenylyl cyclases, PKA catalytic and regulatory subunits, and cyclic nucleotide phosphodiesterases. We have constructed two PKA-repressed reporters for use in high-throughput screens to detect compounds that elevate or reduce PKA activity, thus facilitating the discovery of both inhibitors and activators of these target proteins. Here, we describe steps to construct screening strains and to optimize and conduct these screens.