ABSTRACT
Genetic analysis using high-throughput sequencing is a powerful tool for patients with rare diseases. However, biological and clinical interpretation thereof is difficult, especially when the clinical picture is complex. Multidisciplinary Genome Boards bring together the relevant medical specialties around the patient's medical and genetic file, to optimize the correlation between phenotype and genotype. This often allows the identification of the causal genetic variant in previously unsolved cases. A retrospective study shows that Genome Boards significantly increase the diagnostic rate in complex clinical cases with difficult-to-interpret genetic analysis results, as well as facilitating collaboration between the various medical specialties involved.
Les analyses génétiques par séquençage à haut débit sont un outil puissant pour les patients atteints de maladies rares. Leurs interprétations biologique et clinique sont cependant difficiles, et cela d'autant plus que le tableau clinique est complexe. Les genome boards multidisciplinaires réunissent les spécialités médicales pertinentes autour du dossier médical et génétique du patient, afin d'optimiser la corrélation entre le phénotype et le génotype. Ceci permet souvent d'identifier le variant génétique causal dans des cas jusque-là non élucidés. Une étude rétrospective montre que les genome boards permettent d'augmenter le taux de diagnostic moléculaire pour des cas cliniques complexes avec des résultats d'analyses difficiles à interpréter, en plus de faciliter la collaboration entre les différentes spécialités médicales impliquées.
Subject(s)
High-Throughput Nucleotide Sequencing , Patients , Humans , Retrospective Studies , Genotype , Interdisciplinary StudiesABSTRACT
Interleukin-6 (IL-6) is systemically elevated in obesity and is a predictive factor to develop type 2 diabetes. Pancreatic islet pathology in type 2 diabetes is characterized by reduced beta-cell function and mass, an increased proportion of alpha-cells relative to beta-cells, and alpha-cell dysfunction. Here we show that the alpha cell is a primary target of IL-6 actions. Beginning with investigating the tissue-specific expression pattern of the IL-6 receptor (IL-6R) in both mice and rats, we find the highest expression of the IL-6R in the endocrine pancreas, with highest expression on the alpha-cell. The islet IL-6R is functional, and IL-6 acutely regulates both pro-glucagon mRNA and glucagon secretion in mouse and human islets, with no acute effect on insulin secretion. Furthermore, IL-6 stimulates alpha-cell proliferation, prevents apoptosis due to metabolic stress, and regulates alpha-cell mass in vivo. Using IL-6 KO mice fed a high-fat diet, we find that IL-6 is necessary for high-fat diet-induced increased alpha-cell mass, an effect that occurs early in response to diet change. Further, after high-fat diet feeding, IL-6 KO mice without expansion of alpha-cell mass display decreased fasting glucagon levels. However, despite these alpha-cell effects, high-fat feeding of IL-6 KO mice results in increased fed glycemia due to impaired insulin secretion, with unchanged insulin sensitivity and similar body weights. Thus, we conclude that IL-6 is necessary for the expansion of pancreatic alpha-cell mass in response to high-fat diet feeding, and we suggest that this expansion may be needed for functional beta-cell compensation to increased metabolic demand.
Subject(s)
Glucagon-Secreting Cells/cytology , Interleukin-6/metabolism , Animals , Apoptosis/drug effects , Cell Proliferation/drug effects , Dietary Fats/pharmacology , Feeding Behavior/drug effects , Gene Expression Regulation/drug effects , Glucagon/genetics , Glucagon/metabolism , Glucagon-Secreting Cells/drug effects , Glucose Tolerance Test , Humans , Insulin-Secreting Cells/cytology , Insulin-Secreting Cells/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Phosphorylation/drug effects , Protein Precursors/genetics , Protein Precursors/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar , Receptors, Interleukin-6/genetics , Receptors, Interleukin-6/metabolism , STAT3 Transcription Factor/metabolismABSTRACT
Laminin-5-rich extracellular matrix derived from 804G cells (804G-ECM) engages beta1 integrins to induce spreading, improve glucose-stimulated insulin secretion (GSIS), and increase survival of pancreatic beta cells. The present study examines whether 804G-ECM activates the transcriptional activity of NF-kappaB and the involvement of NF-kappaB in those effects of 804G-ECM on pancreatic beta cells. 804G-ECM induces nuclear translocation and the DNA binding activity of the p65 subunit of NF-kappaB. 804G-ECM-induced nuclear translocation of NF-kappaB was weak as compared with that induced by interleukin-1beta. Transient 804G-ECM-induced DNA binding activity of NF-kappaB (peak at 2 h) and overexpression of NF-kappaB target genes IkappaB alpha and NF-kappaB1(p105) (peak at 4 h) were observed. When NF-kappaB was inhibited by an inhibitor of IkappaB alpha phosphorylation (Bay 11-7082) or by a recombinant adenovirus expressing the nonphosphorylatable form of IkappaB alpha, 804G-ECM-induced cell spreading and actin cytoskeleton organization were reduced. GSIS from cells on 804G-ECM was inhibited 5-fold, whereas cell survival was not affected. In summary, the results indicate that 804G-ECM induces a transient and moderate NF-kappaB activity. This study shows for the first time that ECM-induced NF-kappaB activity is necessary in maintaining GSIS, although it does not affect survival of pancreatic beta cells. The effects of ECM-induced NF-kappaB activity contrast with the deleterious effects of cytokine-induced NF-kappaB activity. It is proposed that transient and moderate NF-kappaB activity is essential for proper function of the pancreatic beta cell.
