Pancreatic islet transplantation has not yet succeeded as an overall treatment for type 1 diabetes because of limited access to donor islets, as well as low efficacy and poor reproducibility of the current procedure. Herein, a method to create islets-like composite clusters (coclusters) from dispersed endocrine cells and supportive cells is described, attempting to improve compatibility with the recipient and more efficiently make use of the donor-derived material. To mimic the extracellular matrix environment, recombinant spider silk functionalized with cell binding motifs are used as 3D support for the coclusters. A cell binding motif derived from fibronectin (FN) was found superior in promoting cell adherence, while a plain RGD-motif incorporated in the repetitive part of the silk protein (2R) increased the mobility and cluster formation of endocrine cells. Self-assembly of a mixture of FN/2R silk is utilized to integrate endocrine cells together with endothelial and mesenchymal cells into islet-like coclusters. Both xenogenic and allogenic versions of these coclusters were found to be viable and were able to respond to dynamic glucose stimulation with insulin release. Moreover, the endothelial cells were found to be colocalized with the endocrine cells, showing that the silk combined with supportive cells may promote vascularization. This method to engineer combined islet-like coclusters allows donor-derived endocrine cells to be surrounded by supportive cells from the recipient, which have the potential to further promote engraftment in the host and considerably reduce risk of rejection.

The GLIS family zinc finger 3 isoform (GLIS3) is a risk gene for Type 1 and Type 2 diabetes, glaucoma and Alzheimer's disease endophenotype. We identified GLIS3 binding sites in insulin secreting cells (INS1) (FDR q<0.05; enrichment range 1.40–9.11 fold) sharing the motif wrGTTCCCArTAGs, which were enriched in genes involved in neuronal function and autophagy and in risk genes for metabolic and neuro-behavioural diseases. We confirmed experimentally Glis3-mediated regulation of the expression of genes involved in autophagy and neuron function in INS1 and neuronal PC12 cells. Naturally-occurring coding polymorphisms in Glis3 in the Goto-Kakizaki rat model of type 2 diabetes were associated with increased insulin production in vitro and in vivo, suggestive alteration of autophagy in PC12 and INS1 and abnormal neurogenesis in hippocampus neurons. Our results support biological pleiotropy of GLIS3 in pathologies affecting β-cells and neurons and underline the existence of trans‑nosology pathways in diabetes and its co-morbidities.

Atherosclerotic lesion development and acceleration of lesion size, leading to a cardiovascular event can be affected by many factors, where both the immune system and lipid levels have been implicated. It is well recognized that patients with chronic inflammatory diseases, such as rheumatoid arthritis (RA) have an increased risk for cardiovascular disease (CVD) compared with the general population. It has also been suggested that CVD presented in RA patients is of an altered, more aggressive, phenotype compared to subjects without RA. Therefore, the investigation of atherosclerosis lesion development during chronic inflammation may lead to novel pathways that are not only relevant to the general population but also able to target this high CVD risk patient group. Thus, there is a need to gain a deeper understanding of how the exacerbated inflammatory state of arthritis affects the atherosclerosis process when both syndromes are presented in the same individual. Such studies are hampered in humans by the influence of different factors, such as the environment and large genetic heterogeneity of the population. We have developed a novel murine model where the human relevant genes of CVD (LDLr, thus increased LDL levels) and RA (MHCII, thus susceptible to collagen-induced arthritis) have been crossed into the common C57Bl6/J strain, enabling both arthritis and atherosclerosis being presented simultaneously in a clinically relevant fashion. This model mirrors the clinical state where the systemic inflammation of arthritis enhances atherosclerosis progression, where mice presenting arthritis have a significant increase in atherosclerotic lesion progression compared with their non-arthritic littermates. Interestingly, there was an inverse correlation with cholesterol levels, but a positive correlation with macrophages, and macrophage associated cytokines but not T cells. This model thus demonstrates that the lipid levels are vital in initiation of lesion development but it is the enhanced innate immune system that is driving the lesion acceleration in a chronic inflammatory state. This novel combined model is now able to be used to investigate altered clinical treatment strategies or novel treatments of atherosclerosis in the context of arthritis

Ex vivo expansion of endocrine cells constitutes an interesting alternative to be able to match the unmet need of transplantable pancreatic islets. However, endocrine cells become fragile once removed from their extracellular matrix (ECM) and typically become senescent and loose insulin expression during conventional 2D culture. Herein we develop a protocol where 3D silk matrices functionalized with ECM-derived motifs are used for generation of insulin-secreting islet-like clusters from mouse and human primary cells. The obtained clusters were shown to attain an islet-like spheroid shape and to maintain functional insulin release upon glucose stimulation in vitro. Furthermore, in vivo imaging of transplanted murine clusters showed engraftment with increasing vessel formation during time. There was no sign of cell death and the clusters maintained or increased in size throughout the period, thus suggesting a suitable cluster size for transplantation.

Event Abstract Back to Event No Records Found Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Transplantation of pancreatic islets is one approach for treatment of diabetes, however, hampered by the low availability of viable islets. Islet isolation leads to disruption of the environment surrounding the endocrine cells, which contributes to eventual cell death. The reestablishment of this environment is vital, why we herein investigated the possibility of using recombinant spider silk to support islets in vitro after isolation. The spider silk protein 4RepCT was formulated into three different formats; 2D-film, fiber mesh and 3D-foam, in order to provide a matrix that can give the islets physical support in vitro. Moreover, cell-binding motifs from laminin were incorporated into the silk protein in order to create matrices that mimic the natural cell environment. Pancreatic mouse islets were thoroughly analyzed for adherence, necrosis and function after in vitro maintenance on the silk matrices. To investigate their suitability for transplantation, we utilized an eye model which allows in vivo imaging of engraftment. Interestingly, islets that had been maintained on silk foam during in vitro culture showed improved revascularization. This coincided with the observation of preserved islet architecture with endothelial cells present after in vitro culture on silk foam. Selected matrices were further evaluated for long-term preservation of human islets. Matrices with the cell-binding motif RGD improved human islet maintenance (from 36% to 79%) with preserved islets architecture and function for over 3 months in vitro. The islets established cell-matrix contacts and formed vessel-like structures along the silk. Moreover, RGD matrices promoted formation of new, insulin-positive islet-like clusters that were connected to the original islets via endothelial cells. On silk matrices with islets from younger donors (<35 year), the amount of newly formed islet-like clusters found after 1 month in culture were almost double compared to the initial number of islets added.

Background and Aims It is well established that patients with Rheumatoid Arthritis (RA) have a higher risk of developing coronary artery disease (CAD). However, it is unclear how the inflammatory process affects atherosclerosis and what specific factors are involved. In this study, we investigated the effect of the pro-atherogenic factor hyperlipidaemia on arthritis incidence and severity. Simultaneously, we have investigated the mutation of the neutrophil cytosolic factor 1 (Ncf-1), a known genetic factor that promotes arthritis susceptibility, and MHCII H-2q on atherosclerosis development. Results We observed that diet-induced hyperlipidaemia prior to induction of collagen induced arthritis (CIA) protected mice against the disease while genetically hyperlipidemic without the use of diet, Ldlr-/- x human ApoB100 transgenic (Ldlr-/-hApoBtg), were equally susceptible to CIA compared to their heterozygous littermates. Next, we investigated Ncf-1 mutation on Ldlr-/-hApoBtg mice. Surprisingly, despite the increased inflammatory/arthritic phenotype induced by Ncf-1 mutation, no difference in the atherosclerotic lesion size was observed. Conclusions Our data shows that hyperlipidaemia-induced by diet have substantial effects on arthritis susceptibility, which in turn differs from hyperlipidaemia acquired on birth due to genetic alterations. By developing a model carrying pro-arthritogenic factors, MHCII H-2q and Ncf-1 mutation, as well as the pro-atherosclerotic factors, Ldlr-/- and hApoBtg, we have established a new model where both arthritis and atherosclerosis are present. These mice will be used to further characterize the impact of systemic inflammation in the form of arthritis in the atherosclerotic process and vice versa.

BACKGROUND:The TNFSF4/TNFRSF4 system, along with several other receptor-ligand pairs, is involved in the recruitment and activation of T-cells and is therefore tentatively implicated in atherosclerosis and acute coronary syndromes. We have previously shown that genetic variants in TNFSF4 are associated with myocardial infarction (MI) in women. This prompted functional studies of TNFSF4 expression.METHODS AND RESULTS:Based on a screening of the TNFSF4 genomic region, a promoter polymorphism (rs45454293) and a haplotype were identified, conceivably involved in gene regulation. The rs45454293T-allele, in agreement with the linked rs3850641G-allele, proved to be associated with increased risk of MI in women. Haplotype-specific chromatin immunoprecipitation of activated polymerase II, as a measure of transcriptional activity in vivo, suggested that the haplotype including the rs45454293 and rs3850641 polymorphisms is functionally important, the rs45454293T- and rs3850641G-alleles being associated with lower transcriptional activity in cells heterozygous for both polymorphisms. The functional role of rs45454293 on transcriptional levels of TNFSF4 was clarified by luciferase reporter assays, where the rs45454293T-allele decreased gene expression when compared with the rs45454293C-allele, while the rs3850641 SNP did not have any effect on TNFSF4 promoter activity. Electromobility shift assay showed that the rs45454293 polymorphism, but not rs3850641, affects the binding of nuclear factors, thus suggesting that the lower transcriptional activity is attributed to binding of one or more transcriptional repressor(s) to the T-allele.CONCLUSIONS:Our data indicate that the TNFSF4 rs45454293T-allele is associated with lower TNFSF4 expression and increased risk of MI.

MicroRNAs regulate a broad range of biological mechanisms. To investigate the relationship between microRNA expression and type 2 diabetes, we compared global microRNA expression in insulin target tissues from three inbred rat strains that differ in diabetes susceptibility.

In two independent human cohorts, the minor allele of SNP rs3850641 in TNFSF4 was significantly more frequent in individuals with myocardial infarction than in controls. In mice, Tnfsf4 expression is associated with increased atherosclerosis. The expression of TNFSF4 in human atherosclerosis and the association between genotype and cerebrovascular disease have not yet been investigated. TNFSF4 messenger RNA (mRNA) levels were significantly higher in human atherosclerotic lesions compared with controls (730 +/- 30 vs 330 +/- 65 arbitrary units, p < 0.01). TNFSF4 was mainly expressed by macrophages in atherosclerotic lesions. In cell culture, endothelial cells upregulated TNFSF4 in response to tumor necrosis factor alpha (TNF-alpha; 460 +/- 110 vs 133 +/- 8 arbitrary units, p < 0.001 after 6 h of stimulation). We analyzed the TNFSF4 gene in 239 patients who had undergone carotid endarterectomy and 138 matching controls from The Biobank of Karolinska Carotid Endarterectomies and Stockholm Heart Epidemiology Program cohorts and 929 patients and 1,382 matching controls from the Sahlgrenska Academy Study on Ischemic Stroke and Case Control Study of Stroke cohorts, limiting inclusion to patients with ischemic stroke. Participants were genotyped for the rs3850641 SNP in TNFSF4. Genotype associations were neither found with TNFSF4 mRNA levels nor with atherosclerosis associated systemic factors or risk for stroke. This study shows that TNFSF4 is expressed on antigen-presenting cells in human carotid atherosclerotic lesions but provides no evidence for an association of TNFSF4 gene variation with the risk for ischemic stroke.

Background: Complex etiology and pathogenesis of pathophysiological components of the cardio-metabolic syndrome have been demonstrated in humans and animal models.Methodology/Principal Findings: We have generated extensive physiological, genetic and genome-wide gene expression profiles in a congenic strain of the spontaneously diabetic Goto-Kakizaki (GK) rat containing a large region (110 cM, 170 Mb) of rat chromosome 1 (RNO1), which covers diabetes and obesity quantitative trait loci (QTL), introgressed onto the genetic background of the normoglycaemic Brown Norway (BN) strain. This novel disease model, which by the length of the congenic region closely mirrors the situation of a chromosome substitution strain, exhibits a wide range of abnormalities directly relevant to components of the cardio-metabolic syndrome and diabetes complications, including hyperglycaemia, hyperinsulinaemia, enhanced insulin secretion both in vivo and in vitro, insulin resistance, hypertriglyceridemia and altered pancreatic and renal histological structures. Gene transcription data in kidney, liver, skeletal muscle and white adipose tissue indicate that a disproportionately high number (43-83%) of genes differentially expressed between congenic and BN rats map to the GK genomic interval targeted in the congenic strain, which represents less than 5% of the total length of the rat genome. Genotype analysis of single nucleotide polymorphisms (SNPs) in strains genetically related to the GK highlights clusters of conserved and strain-specific variants in RNO1 that can assist the identification of naturally occurring variants isolated in diabetic and hypertensive strains when different phenotype selection procedures were applied.Conclusions: Our results emphasize the importance of rat congenic models for defining the impact of genetic variants in well-characterised QTL regions on in vivo pathophysiological features and cis-/trans-regulation of gene expression. The congenic strain reported here provides a novel and sustainable model for investigating the pathogenesis and genetic basis of risks factors for the cardio-metabolic syndrome.

In a case-control study conducted on a sample recruited from Southern Germany (a total of 3,657 cases and 1,211 controls; 885 and 598 women, respectively), Koch et al.1 found no association between common variants in the TNFSF4 gene and myocardial infarction when examining 14 SNPs representing most of the variation across a 40-kb region encompassing TNFSF4. This is the first larger-scale replication study of our original observation of an association between TNFSF4 genotype and myocardial infarction in women made in two independent case-control studies from Sweden2.

Atherosclerosis is the pathological basis for coronary artery disease (CAD), the leading cause of morbidity and mortality in developed countries. CAD and atherosclerosis have long been known to have a familial component and result from the interaction of several genes with a wide range of environmental and lifestyle factors. Because of this complexity, applying the positional cloning approaches to find new CAD susceptibility genes has resulted disappointing and most of them are still unknown. Evidence from epidemiological studies implies a possibility for CAD susceptibility genes independent of classical risk factors. Identification of such genes might reveal novel intriguing biological pathways, making quests for new susceptibility genes in a hypothesis-independent manner worthwhile. Mapping of quantitative traits in mouse is showing to be particularly useful for such purposes. Despite there is no convincing animal model of CAD in a genetically tractable species, manipulated mouse models and inbred strains have been proved informative for aspects of atherosclerosis, the underlying

We recently showed that genetic variants in OX40L are associated with myocardial infarction (MI) and severity of coronary artery disease in human. A number of studies also suggest a possible role for OX40 (the OX40L receptor) as a factor contributing to atherosclerosis. In the present study, the OX40 gene was screened for variants associated with precocious MI, using individuals with MI before the age of 60 and controls. Despite the fact that the OX40 gene is highly conserved between species and that relatively few common genetic variants were encountered, an association with MI was seen for a polymorphism in intron 5 (rs2298212). In silico investigation suggested that genetic variation (rs2298211), linked to this intronic variant, is possibly affecting spliceosome function. Our results provide evidence that variants in human OX40 might influence susceptibility to MI. The relevance of these findings is supported by the vital functions fulfilled by OX40 in mammals as reflected by the high level of evolutionary conservation.