| 1. |
- Blanchi, Bruno, et al.
(author)
-
EndoC-βH5 cells are storable and ready-to-use human pancreatic beta cells with physiological insulin secretion
- 2023
-
In: Molecular Metabolism. - 2212-8778. ; 76
-
Journal article (peer-reviewed)abstract
- Objectives: Readily accessible human pancreatic beta cells that are functionally close to primary adult beta cells are a crucial model to better understand human beta cell physiology and develop new treatments for diabetes. We here report the characterization of EndoC-βH5 cells, the latest in the EndoC-βH cell family. Methods: EndoC-βH5 cells were generated by integrative gene transfer of immortalizing transgenes hTERT and SV40 large T along with Herpes Simplex Virus-1 thymidine kinase into human fetal pancreas. Immortalizing transgenes were removed after amplification using CRE activation and remaining non-excized cells eliminated using ganciclovir. Resulting cells were distributed as ready to use EndoC-βH5 cells. We performed transcriptome, immunological and extensive functional assays. Results: Ready to use EndoC-βH5 cells display highly efficient glucose dependent insulin secretion. A robust 10-fold insulin secretion index was observed and reproduced in four independent laboratories across Europe. EndoC-βH5 cells secrete insulin in a dynamic manner in response to glucose and secretion is further potentiated by GIP and GLP-1 analogs. RNA-seq confirmed abundant expression of beta cell transcription factors and functional markers, including incretin receptors. Cytokines induce a gene expression signature of inflammatory pathways and antigen processing and presentation. Finally, modified HLA-A2 expressing EndoC-βH5 cells elicit specific A2-alloreactive CD8 T cell activation. Conclusions: EndoC-βH5 cells represent a unique storable and ready to use human pancreatic beta cell model with highly robust and reproducible features. Such cells are thus relevant for the study of beta cell function, screening and validation of new drugs, and development of disease models.
|
|
| 2. |
|
|
| 3. |
- Alonso, Lorena, et al.
(author)
-
TIGER : The gene expression regulatory variation landscape of human pancreatic islets
- 2021
-
In: Cell Reports. - : Elsevier BV. - 2211-1247. ; 37:2
-
Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWASs) identified hundreds of signals associated with type 2 diabetes (T2D). To gain insight into their underlying molecular mechanisms, we have created the translational human pancreatic islet genotype tissue-expression resource (TIGER), aggregating >500 human islet genomic datasets from five cohorts in the Horizon 2020 consortium T2DSystems. We impute genotypes using four reference panels and meta-analyze cohorts to improve the coverage of expression quantitative trait loci (eQTL) and develop a method to combine allele-specific expression across samples (cASE). We identify >1 million islet eQTLs, 53 of which colocalize with T2D signals. Among them, a low-frequency allele that reduces T2D risk by half increases CCND2 expression. We identify eight cASE colocalizations, among which we found a T2D-associated SLC30A8 variant. We make all data available through the TIGER portal (http://tiger.bsc.es), which represents a comprehensive human islet genomic data resource to elucidate how genetic variation affects islet function and translates into therapeutic insight and precision medicine for T2D.
|
|
| 4. |
- Cen, Jing, 1985-
(author)
-
Free fatty acids and insulin hypersecretion studied in human islets
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- Free fatty acid (FFA) levels are increased in many obese subjects. High FFA levels stimulate the pancreatic beta-cells but have negative long-term effects. In obese children with high FFA levels circulating insulin concentration is high early in life but decline with age precipitating the development of type 2 diabetes mellitus (T2DM). The present study aims at preventing this development of T2DM by defining underlying mechanisms of insulin hypersecretion. Such mechanisms will be identified by studying regulation of insulin secretion from human pancreatic islets and human EndoC-βH1 cells exposed to elevated FFA levels.We found that elevated concentrations of FFAs acutely stimulate insulin from human pancreatic islets at fasting blood glucose level, with mono-unsatured being more potent than saturated fatty acids. Enhanced secretion was associated with increased glycolytic flux and mitochondrial respiration. Continued exposure to elevated palmitate levels for up to 2 days accentuated insulin secretion, whereas 7 days’ exposure caused secretory decline. Metformin prevented insulin hypersecretion from human islets treated with palmitate for 2 days by decreasing mitochondrial metabolism. In islets exposed to palmitate for 7 days metformin improved insulin secretion by enhancing calcium binding protein sorcin levels and thereby reducing ER stress and apoptosis. Downregulation of sorcin had negative effects on insulin secretion, mitochondrial metabolism and ER stress in human islets and EndoC-βH1 cells. Specific cellular pathways involved in insulin hypersecretion and secretory decline were identified by microarray expression analysis and subsequent bioinformatics in human islets cultured with palmitate for 0, 4, 12 hours, 1, 2, and 7 days.In conclusion, beta-cells respond to elevated levels of FFAs by initially augmenting insulin release followed by declining secretory levels after prolonged exposure. Metformin normalizes these secretory aberrations. Specific signaling pathways and proteins including sorcin contribute to the secretory alterations induced by palmitate. When developing strategies for prevention of T2DM in obese children with elevated FFA levels, metformin should be considered as well as novel strategies involving sorcin and the identified specific pathways.
|
|
| 5. |
- Cnop, Miriam, et al.
(author)
-
Diabetes in Friedreich Ataxia
- 2013
-
In: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 126, s. 94-102
-
Research review (peer-reviewed)abstract
- Diabetes is a common metabolic disorder in patients with Friedreich ataxia. In this Supplement article, we review the clinical data on diabetes in Friedreich ataxia, and the experimental data from rodent and in vitro models of the disease. Increased body adiposity and insulin resistance are frequently present in Friedreich ataxia, but pancreatic cell dysfunction and death are a conditio sine qua non for the loss of glucose tolerance and development of diabetes. The loss of frataxin function in mitochondria accounts for these pathogenic processes in Friedreich ataxia. Mitochondria are essential for the sensing of nutrients by the cell and for the generation of signals that trigger and amplify insulin secretion, known as stimulus-secretion coupling. Moreover, in the intrinsic pathway of apoptosis, pro-apoptotic signals converge on mitochondria, resulting in mitochondrial Bax translocation, membrane permeabilization, cytochrome c release and caspase cleavage. How and at which level frataxin deficiency impacts on these processes in cells is only partially understood. A better understanding of the molecular mechanisms mediating cell demise in Friedreich ataxia will pave the way for new therapeutic approaches.
|
|
| 6. |
|
|
| 7. |
- Cunha, Daniel A., et al.
(author)
-
Thrombospondin 1 protects pancreatic beta-cells from lipotoxicity via the PERK-NRF2 pathway
- 2016
-
In: Cell Death and Differentiation. - : Springer Science and Business Media LLC. - 1350-9047 .- 1476-5403. ; 23:12, s. 1995-2006
-
Journal article (peer-reviewed)abstract
- The failure of beta-cells has a central role in the pathogenesis of type 2 diabetes, and the identification of novel approaches to improve functional beta-cell mass is essential to prevent/revert the disease. Here we show a critical novel role for thrombospondin 1 (THBS1) in beta-cell survival during lipotoxic stress in rat, mouse and human models. THBS1 acts from within the endoplasmic reticulum to activate PERK and NRF2 and induce a protective antioxidant defense response against palmitate. Prolonged palmitate exposure causes THBS1 degradation, oxidative stress, activation of JNK and upregulation of PUMA, culminating in beta-cell death. These findings shed light on the mechanisms leading to beta-cell failure during metabolic stress and point to THBS1 as an interesting therapeutic target to prevent oxidative stress in type 2 diabetes.
|
|
| 8. |
- Gotthardt, Martin, et al.
(author)
-
Detection and quantification of beta cells by PET imaging : why clinical implementation has never been closer
- 2018
-
In: Diabetologia. - : SPRINGER. - 0012-186X .- 1432-0428. ; 61:12, s. 2516-2519
-
Journal article (peer-reviewed)abstract
- In this issue of Diabetologia, Alavi and Werner (10.1007/s00125-018-4676-1) criticise the attempts to use positron emission tomography (PET) for in vivo imaging of pancreatic beta cells, which they consider as futile'. In support of this strong statement, they point out the limitations of PET imaging, which they believe render beta cell mass impossible to estimate using this method. In our view, the Alavi and Werner presentation of the technical limitations of PET imaging does not reflect the current state of the art, which leads them to questionable conclusions towards the feasibility of beta cell imaging using this approach. Here, we put forward arguments in favour of continuing the development of innovative technologies enabling in vivo imaging of pancreatic beta cells and concisely present the current state of the art regarding putative technical limitations of PET imaging. Indeed, far from being a futile' effort, we demonstrate that beta cell imaging is now closer than ever to becoming a long-awaited clinical reality.
|
|
| 9. |
- Johansson, Bente B, et al.
(author)
-
Diabetes and pancreatic exocrine dysfunction due to mutations in the carboxyl-ester lipase gene (CEL-MODY) : a protein misfolding disease
- 2011
-
In: Journal of Biological Chemistry. - Bethesda, Md. : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 286:40, s. 34593-34605
-
Journal article (peer-reviewed)abstract
- CEL-MODY, diabetes with pancreatic lipomatosis and exocrine dysfunction, is due to dominant frame-shift mutations in the acinar cell carboxyl-ester lipase gene (CEL). As Cel knock-out mice do not express the phenotype and the mutant protein has an altered, intrinsically disordered tandem repeat domain, we hypothesized that the disease mechanism might involve a negative effect of the mutant protein. In silico analysis showed that the pI of the tandem repeat was markedly increased from pH 3.3 in wild-type (WT) to 11.8 in mutant (MUT) human CEL. By stably over-expressing CEL-WT and CEL-MUT in HEK293 cells, we found similar glycosylation, ubiquitination, constitutive secretion and quality control of the two proteins. The CEL-MUT protein demonstrated, however, a high propensity to form aggregates found intracellularly and extracellularly. Different physico-chemical properties of the intrinsically disordered tandem repeat domains of WT and MUT proteins may contribute to different short-range and long-range interactions with the globular core domain and other macromolecules, including cell membranes. Thus, we propose that CEL-MODY is a protein misfolding disease caused by a negative gain-of-function effect of the mutant proteins in pancreatic tissues.
|
|
| 10. |
|
|
