Standard cell therapy equipment, including the gold standard cell processor to purify human islets for clinical transplantation, is rarely refrigerated, potentially exposing cells to elevated... Show moreStandard cell therapy equipment, including the gold standard cell processor to purify human islets for clinical transplantation, is rarely refrigerated, potentially exposing cells to elevated temperatures during the centrifugation step. Custom cooling systems have a direct benefit on human islet viability and function. The current study was designed to test the effectiveness of a newly developed, readily available cooled cell processor system requiring minimal modifications and to evaluate its impact on human cell viability and the GMP cleanroom environment. The cooler system, a mechanically refrigerated heat exchanger set at -30 degrees C was used to deliver cooled medical grade dry air to the cell processor bowl through a hole drilled in the centrifuge cover. With the limited availability of pancreas donors in Qatar, system validation was done with continuous density gradient purification of pooled human bone marrow buffy coat. Sterility, turbulence, and particle count were measured in class C and class B clean room environments. No turbulence developed around the cooled cell processor, and no excess 0.5 mu m and 5 mu m airborne particulates were generated as per cleanroom GMP standards. At the beginning and end of the collection steps, the temperature rose respectively to 21.50 degrees C +/- 0.34 degrees C and 21.93 degrees C +/- 0.20 degrees C in the non-cooled cell processor and to only 10.9 degrees C +/- 0.17 degrees C and 11.16 degrees C +/- 0.35 degrees C in the cooledcell processor (p <0.05). The cooled cell processor led to both improved recovery (98%) of the mononuclear cell fraction and viability (100% +/- 2%) post-processing. The new cooling system effectively reduces the heat produced by the cell processor while having no particulate impact on the GMP clean room environment. The cooled cell processor described here is an inexpensive ($16,000 without including taxes, customs clearance, and transportation) and minimally invasive method to provide robust cooling. Currently, this technology in the GMP cell therapy facility is being applied to human islet cell isolation and transplantation for the clinical program. Show less
Background: Non-coding genetic variants that influence gene transcription in pancreatic islets play a major role in the susceptibility to type 2 diabetes (T2D), and likely also contribute to type 1... Show moreBackground: Non-coding genetic variants that influence gene transcription in pancreatic islets play a major role in the susceptibility to type 2 diabetes (T2D), and likely also contribute to type 1 diabetes (T1D) risk. For many loci, however, the mechanisms through which non-coding variants influence diabetes susceptibility are unknown. Results: We examine splicing QTLs (sQTLs) in pancreatic islets from 399 human donors and observe that common genetic variation has a widespread influence on the splicing of genes with established roles in islet biology and diabetes. In parallel, we profile expression QTLs (eQTLs) and use transcriptome-wide association as well as genetic co-localization studies to assign islet sQTLs or eQTLs to T2D and T1D susceptibility signals, many of which lack candidate effector genes. This analysis reveals biologically plausible mechanisms, including the association of T2D with an sQTL that creates a nonsense isoform in ERO1B, a regulator of ER-stress and proinsulin biosynthesis. The expanded list of T2D risk effector genes reveals overrepresented pathways, including regulators of G-protein-mediated cAMP production. The analysis of sQTLs also reveals candidate effector genes for T1D susceptibility such as DCLRE1B, a senescence regulator, and lncRNA MEG3. Conclusions: These data expose widespread effects of common genetic variants on RNA splicing in pancreatic islets. The results support a role for splicing variation in diabetes susceptibility, and offer a new set of genetic targets with potential therapeutic benefit. Show less
Piemonti, L.; Andres, A.; Casey, J.; Koning, E. de; Engelse, M.; Hilbrands, R.; ... ; Berney, T. 2021
Allogeneic islet transplantation is a standard of care treatment for patients with labile type 1 diabetes in many countries around the world, including Japan, the United Kingdom, Australia, much of... Show moreAllogeneic islet transplantation is a standard of care treatment for patients with labile type 1 diabetes in many countries around the world, including Japan, the United Kingdom, Australia, much of continental Europe, and parts of Canada. The United States is now endorsing islet cell treatment for type 1 diabetes, but the FDA has chosen to consider islets as a biologic that requires licensure, making the universal implementation of the procedure in the clinic very challenging and opening the manufacture of islet grafts to private companies. The commercialization of human tissues raises significant legal and ethical issues and ironically leads to a situation where treatments developed as a result of the scientific and economic efforts of academia over several decades become exploited exclusively by for-profit entities. Show less
Genetic studies promise to provide insight into the molecular mechanisms underlying type 2 diabetes (T2D). Variants associated with T2D are often located in tissue-specific enhancer clusters or... Show moreGenetic studies promise to provide insight into the molecular mechanisms underlying type 2 diabetes (T2D). Variants associated with T2D are often located in tissue-specific enhancer clusters or super-enhancers. So far, such domains have been defined through clustering of enhancers in linear genome maps rather than in three-dimensional (3D) space. Furthermore, their target genes are often unknown. We have created promoter capture Hi-C maps in human pancreatic islets. This linked diabetes-associated enhancers to their target genes, often located hundreds of kilobases away. It also revealed >1,300 groups of islet enhancers, super-enhancers and active promoters that form 3D hubs, some of which show coordinated glucose-dependent activity. We demonstrate that genetic variation in hubs impacts insulin secretion heritability, and show that hub annotations can be used for polygenic scores that predict T2D risk driven by islet regulatory variants. Human islet 3D chromatin architecture, therefore, provides a framework for interpretation of T2D genome-wide association study (GWAS) signals. Show less
Background: Genome-wide association studies have identified susceptibility genes for development of type 2 diabetes. We aimed to examine whether a subset of these (comprising FTO, IDE, KCNJ11,... Show moreBackground: Genome-wide association studies have identified susceptibility genes for development of type 2 diabetes. We aimed to examine whether a subset of these (comprising FTO, IDE, KCNJ11, PPARG and TCF7L2) were transcriptionally restricted to or enriched in human beta cells by sorting islet cells into alpha and beta-specific fractions. We also aimed to correlate expression of these transcripts in both alpha and beta cell types with phenotypic traits of the islet donors and to compare diabetic and non-diabetic cells. Methodology/Principal Findings: Islet cells were sorted using a previously published method and RNA was extracted, reverse transcribed and used as the template for quantitative PCR. Sorted cells were also analysed for insulin and glucagon immunostaining and insulin secretion from the beta cells as well as insulin, glucagon and GLP-1 content. All five genes were expressed in both alpha and beta cells, with significant enrichment of KCNJ11 in the beta cells and of TCF7L2 in the alpha cells. The ratio of KCNJ11 in beta to alpha cells was negatively correlated with BMI, while KCNJ11 expression in alpha cells was negatively correlated with age but not associated with BMI. Beta cell expression of glucagon, TCF7L2 and IDE was increased in cells from islets that had spent more time in culture prior to cell sorting. In beta cells, KCNJ11, FTO and insulin were positively correlated with each other. Diabetic alpha and beta cells had decreased expression of insulin, glucagon and FTO. Conclusions/Significance: This study has identified novel patterns of expression of type 2 diabetes susceptibility genes within sorted islet cells and suggested interactions of gene expression with age or BMI of the islet donors. However, expression of these genes in islets is less associated with BMI than has been found for other tissues. Show less
