Vainio, S. | bioRxiv Science

bioRxiv2019

Ureteric Bud Cells Programmed from Embryonic Stem Cells Obtain Competence for Secondary Induction in the Kidney

Generation of kidney organoids from pluripotent stem cells (PSCs) is regarded as a potentially powerful way to study kidney development, disease, and regeneration. Direct differentiation of PSCs towards renal lineages is well studied, however, most of the studies relates to generation of nephron progenitor population from PSCs. Until now, differentiation of PSCs into ureteric bud (UB) progenitor cells demonstrates limited success. Here, we describe a simple, efficient and reproductive protocol to direct differentiation of mouse embryonic stem cells (mESCs) into UB progenitor cells. The mESC-derived UB cells were able to induce nephrogenesis when placed in the interaction with the primary metanephric mesenchyme (pMM). In generated kidney organoids, the embryonic pMM developed nephron structures and the mESC-derived UB cells formed network of collecting ducts, connected with the nephron tubules. Altogether, our studies established an uncomplicated and reproducible platform for kidney disease modelling, drug testing and regenerative medicine applications.

developmental biology↗

bioRxiv2019

Trisk95 as Novel Skin Mirror for Normal and Diabetic Systemic Glucose Level

Coping with diabetes requires frequent and even today mostly invasive blood glucose-based monitoring. Partly due to this invasive nature and the associated reduced skin wound healing and increased risk of infection, non-invasive glucose monitoring technologies would represent considerable progress. Edited keratinocytes may enable such a function.\n\nTo address this hypothesis, we conducted a proteomic screen in the skin by making use of the experimental in vivo mouse model of type I diabetes alongside controls. We identified Trisk 95 as the only protein whose expression is induced in response to high blood glucose. A luciferase reporter assay demonstrated that induction of Trisk 95 expression occurs not only at the protein level but also transcriptionally. This induction was associated with a marked elevation in the Fluo-4 signal, suggesting a role for intracellular calcium changes in the signalling cascade. Strikingly, these changes lead concurrently to fragmentation of the mitochondria. As judged from the knockout findings, both the calcium flux and the mitochondrial phenotype were dependent on Trisk 95 function, since the phenotypes in question were abolished.\n\nThe data demonstrate that the skin represents an organ that reacts robustly and thus mirrors changes in systemic blood glucose levels. The findings are also consistent with a channelling model of Trisk 95 that serves as an insulin-independent but glucose-responsive biomarker taking part in releasing calcium from the cellular stores in the skin. The skin cells may thus provide a novel mean for glucose monitoring when analysing changes in labelled Trisk 95 and calcium. By that, this study is the first proof of the concept of our registered patent (No. PCT FI2016/050917), which proposes the use of cells as biosensors for developing personalized health-monitoring devices.

cell biology↗