Abstract
The past decade revealed that cell identity changes, such as dedifferentiation or transdifferentiation, accompany the insulin-producing β-cell decay in most diabetes conditions. Mapping and controlling the mechanisms governing these processes is, thus, extremely valuable for managing the disease progression. Extracellular glucose is known to influence cell identity by impacting the redox balance. Here, we use global proteomics and pathway analysis to map the response of differentiating human pancreatic progenitors to chronically increased in vitro glucose levels. We show that exogenous high glucose levels impact different protein subsets in a concentration-dependent manner. In contrast, regardless of concentration, glucose elicits an antipodal effect on the proteome landscape, inducing both beneficial and detrimental changes in regard to achieving the desired islet cell fingerprint. Furthermore, we identified that only a subgroup of these effects and pathways are regulated by changes in redox balance. Our study highlights a complex effect of exogenous glucose on differentiating pancreas progenitors characterized by a distinct proteome signature.
Highlights
Introduction iationsA shared feature of most diabetes disorders is the ultimate loss of functional insulinproducing pancreatic β-cells
For human-induced pluripotent stem cell (hiPSC) differentiation, we employed one of the most reliable and widely used protocols, elaborated by [24], which consists of seven differentiation steps over a period of one month
Starting at the pancreatic progenitor stage, cells were exposed to the appropriate differentiation cocktail containing either the protocol “standard” 20 mM glucose or higher glucose levels of 25 and 30 mM (Figure 1a)
Summary
The hierarchical clustering of the averaged TMT ratios of 4947 differentially expressed proteins between stage 7 cells and human islets revealed the highest glucose concentration to have the strongest impact on the proteome landscape (Figure 1c), with the samples exposed to 30 mM glucose clustering farther away from the standard control (20 mM glucose). The samples exposed to the higher glucose concentration displayed a high overall inter-replicon variation, which could account for fewer markers passing the significance threshold in this condition These results suggest that increased glucose concentrations impact islet cell fate acquisition, without a significant impact on hormone expression, besides glucagon (GCG). The dysregulation of this subset of proteins was the most representative for the global proteome landscape (Supplementary Figure S1a) These results suggest that mildly increased glucose levels inhibit pathways involved in neuronal development. 25-mM-exposed samples, suggesting its potential impact on the differentiation potential
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