The transCampus Metabolic Training Programme Explores the Link of SARS-CoV-2 Virus to Metabolic Disease

Currently, we are experiencing a true pandemic of a communicable disease by the virus SARS-CoV-2 holding the whole world firmly in its grasp. Amazingly and unfortunately, this virus uses a metabolic and endocrine pathway via ACE2 to enter our cells causing damage and disease. Our international research training programme funded by the German Research Foundation has a clear mission to train the best students wherever they may come from to learn to tackle the enormous challenges of diabetes and its complications for our society. A modern training programme in diabetes and metabolism does not only involve a thorough understanding of classical physiology, biology and clinical diabetology but has to bring together an interdisciplinary team. With the arrival of the coronavirus pandemic, this prestigious and unique metabolic training programme is facing new challenges but also new opportunities. The consortium of the training programme has recognized early on the need for a guidance and for practical recommendations to cope with the COVID-19 pandemic for the community of patients with metabolic disease, obesity and diabetes. This involves the optimal management from surgical obesity programmes to medications and insulin replacement. We also established a global registry analyzing the dimension and role of metabolic disease including new onset diabetes potentially triggered by the virus. We have involved experts of infectious disease and virology to our faculty with this metabolic training programme to offer the full breadth and scope of expertise needed to meet these scientific challenges. We have all learned that this pandemic does not respect or heed any national borders and that we have to work together as a global community. We believe that this transCampus metabolic training programme provides a prime example how an international team of established experts in the field of metabolism can work together with students from all over the world to address a new pandemic.

Birth and coming of age of islet autoantibodies

This review takes the reader through 45 years of islet autoantibody research, from the discovery of islet‐cell antibodies in 1974 to today’s population‐based screening for presymptomatic early‐stage type 1 diabetes. The review emphasizes the current practical value of, and factors to be considered in, the measurement of islet autoantibodies.

T cell receptor repertoires after adoptive transfer of expanded allogeneic regulatory T cells

Regulatory T cell (T_reg ) therapy has been exploited in autoimmune disease, solid organ transplantation and in efforts to prevent or treat graft-versus-host disease (GVHD). However, our knowledge on the in-vivo persistence of transfused T_reg is limited. Whether T_reg transfusion leads to notable changes in the overall T_reg repertoire or whether longevity of T_reg in the periphery is restricted to certain clones is unknown. Here we use T cell receptor alpha chain sequencing (TCR-α-NGS) to monitor changes in the repertoire of T_reg upon polyclonal expansion and after subsequent adoptive transfer. We applied TCR-α-NGS to samples from two patients with chronic GVHD who received comparable doses of stem cell donor derived expanded T_reg . We found that in-vitro polyclonal expansion led to notable repertoire changes in vitro and that T_reg cell therapy altered the peripheral T_reg repertoire considerably towards that of the infused cell product, to different degrees, in each patient. Clonal changes in the peripheral blood were transient and correlated well with the clinical parameters. We suggest that T cell clonotype analyses using TCR sequencing should be considered as a means to monitor longevity and fate of adoptively transferred T cells.

Sources of errors and uncertainties in the assessment of forest soil carbon stocks at different scales-review and recommendations

Spatially explicit knowledge of recent and past soil organic carbon (SOC) stocks in forests will improve our understanding of the effect of human- and non-human-induced changes on forest C fluxes. For SOC accounting, a minimum detectable difference must be defined in order to adequately determine temporal changes and spatial differences in SOC. This requires sufficiently detailed data to predict SOC stocks at appropriate scales within the required accuracy so that only significant changes are accounted for. When designing sampling campaigns, taking into account factors influencing SOC spatial and temporal distribution (such as soil type, topography, climate and vegetation) are needed to optimise sampling depths and numbers of samples, thereby ensuring that samples accurately reflect the distribution of SOC at a site. Furthermore, the appropriate scales related to the research question need to be defined: profile, plot, forests, catchment, national or wider. Scaling up SOC stocks from point sample to landscape unit is challenging, and thus requires reliable baseline data. Knowledge of the associated uncertainties related to SOC measures at each particular scale and how to reduce them is crucial for assessing SOC stocks with the highest possible accuracy at each scale. This review identifies where potential sources of errors and uncertainties related to forest SOC stock estimation occur at five different scales-sample, profile, plot, landscape/regional and European. Recommendations are also provided on how to reduce forest SOC uncertainties and increase efficiency of SOC assessment at each scale.

Expression of the Protein Tyrosine Phosphatase-like Protein IA-2 During Pancreatic Islet Development

A tyrosine phosphatase-like protein, IA-2, is a major autoantigen in Type 1 diabetes but its role in islet function is unclear. Tyrosine phosphorylation mediates regulation of cellular processes such as exocytosis, cell growth, and cell differentiation. To investigate the potential involvement of IA-2 in islet differentiation and insulin secretion, we analyzed by immunohistochemistry expression of IA-2 during islet development in fetal rats and during the maturation of insulin secretory responses after birth. In the fetus, IA-2 immunoreactivity was detected in primitive islets positive for insulin and glucagon at 12 days' gestation. Subsequently, IA-2 was only weakly detectable in the fetal pancreas. In neonatal rat, a progressive increase in IA-2 immunoreactivity was observed in islets from very low levels at 1 day of age to moderate labeling at 10 days. In the adult, relatively high levels of IA-2 were detected in islets, with heterogeneous expression in individual cells within each islet. IA-2 marks a population of endocrine cells that transiently appear early in pancreatic ontogeny. Islet IA-2 expression reappears after birth concomitant with the development of mature insulin secretory responses, consistent with a role for this protein in regulated hormone secretion.

Validation of a rapid type 1 diabetes autoantibody screening assay for community-based screening of organ donors to identify subjects at increased risk for the disease

The Network for Pancreatic Organ donors with Diabetes (nPOD) programme was developed in response to an unmet research need for human pancreatic tissue obtained from individuals with type 1 diabetes mellitus and people at increased risk [i.e. autoantibody (AAb)-positive] for the disease. This necessitated the establishment of a type 1 diabetes-specific AAb screening platform for organ procurement organizations (OPOs). Assay protocols for commercially available enzyme-linked immunosorbent assays (elisas) determining AAb against glutamic acid decarboxylase (GADA), insulinoma-associated protein-2 (IA-2A) and zinc transporter-8 (ZnT8A) were modified to identify AAb-positive donors within strict time requirements associated with organ donation programmes. These rapid elisas were evaluated by the international islet AAb standardization programme (IASP) and used by OPO laboratories as an adjunct to routine serological tests evaluating donors for organ transplantation. The rapid elisas performed well in three IASPs (2011, 2013, 2015) with 98-100% specificity for all three assays, including sensitivities of 64-82% (GADA), 60-64% (IA-2A) and 62-68% (ZnT8A). Since 2009, nPOD has screened 4442 organ donors by rapid elisa; 250 (5·6%) were identified as positive for one AAb and 14 (0.3%) for multiple AAb with 20 of these cases received by nPOD for follow-up studies (14 GADA+, two IA-2A(+) , four multiple AAb-positive). Rapid screening for type 1 diabetes-associated AAb in organ donors is feasible, allowing for identification of non-diabetic, high-risk individuals and procurement of valuable tissues for natural history studies of this disease.

Abundant cytomegalovirus (CMV) reactive clonotypes in the CD8(+) T cell receptor alpha repertoire following allogeneic transplantation

Allogeneic stem cell transplantation is potentially curative, but associated with post-transplantation complications, including cytomegalovirus (CMV) infections. An effective immune response requires T cells recognizing CMV epitopes via their T cell receptors (TCRs). Little is known about the TCR repertoire, in particular the TCR-α repertoire and its clinical relevance in patients following stem cell transplantation. Using next-generation sequencing we examined the TCR-α repertoire of CD8(+) T cells and CMV-specific CD8(+) T cells in four patients. Additionally, we performed single-cell TCR-αβ sequencing of CMV-specific CD8(+) T cells. The TCR-α composition of human leucocyte antigen (HLA)-A*0201 CMVpp65- and CMVIE -specific T cells was oligoclonal and defined by few dominant clonotypes. Frequencies of single clonotypes reached up to 11% of all CD8(+) T cells and half of the total CD8(+) T cell repertoire was dominated by few CMV-reactive clonotypes. Some TCR-α clonotypes were shared between patients. Gene expression of the circulating CMV-specific CD8(+) T cells was consistent with chronically activated effector memory T cells. The CD8(+) T cell response to CMV reactivation resulted in an expansion of a few TCR-α clonotypes to dominate the CD8(+) repertoires. These results warrant further larger studies to define the ability of oligoclonally expanded T cell clones to achieve an effective anti-viral T cell response in this setting.

The relative merits of cord blood as a cell source for autologous T regulatory cell therapy in type 1 diabetes

Cord blood has been used as a cell source for therapeutic purposes in children with type 1 diabetes and other disorders. Here, we explore the benefits of cord blood as an autologous source of T regulatory cells for immune cell therapy in patients. CD4(+)CD25(+) T regulatory cells were isolated from cord blood and adult peripheral blood of healthy donors and compared during and after expansion in a 14-day protocol incorporating anti-CD3/anti-CD28 beads, and IL-2 with or without rapamycin. Cord blood T regulatory cells were largely naïve (89±7 vs. 31±10% in young adults, p<0.0001), and had higher expansion yields (median 5,968-fold) than adult T regulatory cells (median 516-fold, p=0.001) and adult naïve T regulatory cells (median 820-fold, p=0.003). Rapamycin reduced expansion yields, but was not necessary to obtain pure expanded cord blood T regulatory cells as judged by FOXP3 staining (94±3%), methylation status of FOXP3 (97%), and intracellular effector cytokine staining (< 6%). Expanded adult T regulatory cells were much less pure in the absence of rapamycin (72±19% FOXP3; 76% by methylation status, <13% INF-γ, <16% IL-4, <5% IL-17 positive), but purity was achieved by inclusion of rapamycin during expansion. Despite differences in purity, all preparations of expanded T regulatory from all sources were able to strongly suppress proliferation of T effector cells in vitro. Our findings suggest that cord blood is an excellent source of T regulatory cells for expansion and autologous cell therapy that may be considered as a strategy to prevent immune-mediated destruction of beta cells in type 1 diabetes.

IGRP and insulin vaccination induce CD8+ T cell-mediated autoimmune diabetes in the RIP-CD80GP mouse

Autoimmune diabetes is characterized by autoantigen-specific T cell-mediated destruction of pancreatic islet beta cells, and CD8(+) T cells are key players during this process. We assessed whether the bitransgenic RIP-CD80 x RIP-LCMV-GP (RIP-CD80GP) mice may be a versatile antigen-specific model of inducible CD8(+) T cell-mediated autoimmune diabetes. Antigen-encoding DNA, peptide-loaded dendritic cells and antigen plus incomplete Freund's adjuvant were used for vaccination. Of 14 pancreatic proteins tested by DNA vaccination, murine pre-proinsulin 2 (100% of mice; median time after vaccination, 60 days) and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) (77%, 58 days) could induce diabetes. Vaccination with DNA encoding for zinc transporter 8, Ia-2, Ia-2β, glutamic acid decarboxylase 67 (Gad67), chromogranin A, insulinoma amyloid polypeptide and homeobox protein Nkx-2.2 induced diabetes development in 25-33% of mice. Vaccination with DNA encoding for Gad65, secretogranin 5, pancreas/duodenum homeobox protein 1 (Pdx1), carboxyl ester lipase, glucagon and control hepatitis B surface antigen (HBsAg) induced diabetes in <20% of mice. Diabetes induction efficiency could be increased by DNA vaccination with a vector encoding a ubiquitin-antigen fusion construct. Diabetic mice had florid T cell islet infiltration. CD8(+) T cell targets of IGRP were identified with a peptide library-based enzyme-linked immunospot assay, and diabetes could also be induced by vaccination with major histocompatibility complex (MHC) class I-restricted IGRP peptides loaded on mature dendritic cells. Vaccination with antigen plus incomplete Freund's adjuvant, which can prevent diabetes in other models, led to rapid diabetes development in the RIP-CD80GP mouse. We conclude that RIP-CD80GP mice are a versatile model of antigen specific autoimmune diabetes and may complement existing mouse models of autoimmune diabetes for evaluating CD8(+) T cell-targeted prevention strategies.

Next-generation sequencing for viruses in children with rapid-onset type 1 diabetes

AIMS/HYPOTHESIS

Viruses are candidate causative agents in the pathogenesis of autoimmune (type 1) diabetes. We hypothesised that children with a rapid onset of type 1 diabetes may have been exposed to such agents shortly before the initiation of islet autoimmunity, possibly at high dose, and thus study of these children could help identify viruses involved in the development of autoimmune diabetes.

METHODS

We used next-generation sequencing to search for viruses in plasma samples and examined the history of infection and fever in children enrolled in The Environmental Determinants of Diabetes in the Young (TEDDY) study who progressed to type 1 diabetes within 6 months from the appearance of islet autoimmunity, and in matched islet-autoantibody-negative controls.

RESULTS

Viruses were not detected more frequently in plasma from rapid-onset patients than in controls during the period surrounding seroconversion. In addition, infection histories were found to be similar between children with rapid-onset diabetes and control children, although episodes of fever were reported less frequently in children with rapid-onset diabetes.

CONCLUSIONS/INTERPRETATION

These findings do not support the presence of viraemia around the time of seroconversion in young children with rapid-onset type 1 diabetes.