The quest to make fully functional human pancreatic beta cells from embryonic stem cells: climbing a mountain in the clouds

Abstract

The production of fully functional insulin-secreting cells to treat diabetes is a major goal of regenerative medicine. In this article, I review progress towards this goal over the last 15 years from the perspective of a beta cell biologist. I describe the current state-of-the-art, and speculate on the general approaches that will be required to identify and achieve our ultimate goal of producing functional beta cells. The need for deeper phenotyping of heterogeneous cultures of stem cell derived islet-like cells in parallel with a better understanding of the heterogeneity of the target cell type(s) is emphasised. This deep phenotyping should include high-throughput single-cell analysis, as well as comprehensive 'omics technologies to provide unbiased characterisation of cell products and human beta cells. There are justified calls for more detailed and well-powered studies of primary human pancreatic beta cell physiology, and I propose online databases of standardised human beta cell responses to physiological stimuli, including both functional and metabolomic/proteomic/ transcriptomic profiles. With a concerted, community-wide effort, including both basic and applied scientists, beta cell replacement will become a clinical reality for patients with diabetes.Keywords Embryonic stem cells . Glucose-stimulated insulin release . Human pancreatic islet beta cells . Review Abbreviation PDX1 Pancreatic and duodenal homeobox 1The case for beta cell replacement in diabetes Diabetes mellitus was recognised early in the era of regenerative medicine research as an obvious indication for a stem cell based therapy. Type 1 diabetes results from the loss of more than 80% of an individual's pancreatic beta cells, while type 2 diabetes occurs when there is insufficient functional beta cell mass to meet the body's needs. The replacement of lost or dysfunctional beta cells in all patients that require it is one of the most important, but elusive, goals of diabetes research. The rationale for beta cell replacement is clear, given the success with which islet cell transplants reduce dangerous hypoglycaemic events and slow the progression of complications [1][2][3]. Pancreatic beta cells have evolved as master regulators of metabolic homeostasis, sensing glucose and other nutrients and releasing appropriate insulin to induce their storage. We understand the basics of beta cell biology, especially the ionic mechanisms underlying insulin release in response to large and abrupt glucose stimuli, which include a rapid rise in cytosolic Ca 2+ subsequent to the metabolismdriven closure of K ATP channels, as well as a plethora of coupling factors [4]. However, we do not understand precisely how human beta cells respond to physiological stimuli and make fate decisions.There are a number of possible ways to replace beta cells in patients with diabetes. Beta cell proliferation could theoretically be induced from the few remaining beta cells in people Electronic supplementary material The online version of this article

Local and regional control of calcium dynamics in the pancreatic islet

“…Great strides have been made in recent years to develop β‐like cells from human embryonic stem (hES) and induced pluripotent stem cells (iPS) . Intriguing questions remain as to whether these resemble any of the islet cell types described by our functional imaging studies described above, as well as those defined by Grompe and colleagues .…”

Encapsulation boosts islet-cell signature in differentiating human induced pluripotent stem cells via integrin signalling

“…Despite an increasing number of differentiation protocols, the efficient generation of a stable mature and functional insulin-producing β -cell is yet to be convincingly achieved 4 , 5…”

Phosphorylation of NEUROG3 Links Endocrine Differentiation to the Cell Cycle in Pancreatic Progenitors

“…Production of large numbers of functional β cells from human embryonic stem cells (hESCs) could address this unmet need. Over the past decade, efforts to generate these cells have culminated in “β-like cells,” which resemble β cells yet remain functionally immature (Johnson, 2016; Kieffer, 2016; Pagliuca and Melton, 2013). However, the number of β-like cells that are formed varies between biological replicates and laboratories (Rezania et al, 2014), making consistent endocrine cell formation difficult and expensive (Rostovskaya et al, 2015).…”