Impaired activation of STAT5 upon IL-2 stimulation in Tregs and elevated sIL-2R in Sjögren’s syndrome

Background Interleukin-2 (IL-2) and the high-affinity IL-2 receptor (IL-2R) are essential for the survival of regulatory T cells (Tregs) which are the main players in immune tolerance and prevention of autoimmune diseases. Sjögren’s syndrome (SS) is a chronic autoimmune disease predominantly affecting women and is characterised by sicca symptoms including oral and ocular dryness. The aim of this study was to investigate an association between IL-2R and Treg function in patients with SS of different severity defined by the salivary flow rate. Methods In a cross-sectional study, we determined plasma soluble IL-2R (sIL-2R) levels in women with SS (n=97) and healthy females (n=50) using ELISA. A subset of those (n=51) was screened for Treg function measured by the STAT5 signalling response to IL-2 using phospho-flow cytometry. Results We found that elevated plasma levels of sIL-2R were positively associated with the severity of SS reflected by a pathologically low salivary flow. Phospho-flow analysis revealed that patients with SS have a significantly lower frequency of pSTAT5+ Tregs upon IL-2 stimulation compared with healthy individuals, while the frequency of Tregs and pSTAT5 in conventional T cells remained unchanged. In addition, we observed more pSTAT5+ Tregs at baseline in patients with SS, which is significantly associated with seropositivity and elevated sIL-2R. Conclusions Our data indicates that Tregs have a weakened immunosuppressive function in patients with SS due to impaired IL-2/IL-2R signalling capacity. This could mediate lymphocytic infiltration into salivary glands inducing sicca symptoms. We believe that sIL-2R could act as a useful indicator for SS and disease severity.publishedVersio

Interleukin-2 receptor in the pathogenesis of diabetic complications and Sjögren's syndrome

The cytokine interleukin-2 (IL-2) acts as a double-edged sword by promoting both immunity and immune tolerance. Regulatory T cells (Tregs) are responsible for maintaining self-tolerance and constitutively express the high affinity form of the IL-2 receptor (IL-2R). IL-2/IL-2R signalling is crucial for the survival of Tregs and disruptions can promote the development of autoimmune diseases, such as type 1 diabetes (T1D) and Sjögren’s syndrome (SS). Elevated plasma levels of the soluble form of IL-2R (sIL-2R) have been associated with different autoimmune diseases including T1D and SS. Autoimmune diseases are chronic and frequently lead to complications of various forms. In people with diabetes, the risk of developing complications is modified by numerous factors including duration of disease and level of glycaemic control and can affect vital organs including eyes, kidneys and blood vessels leading to retinopathy, nephropathy and cardiovascular disease (CVD). The role of immune factors and its complex architecture in diabetic complications has not been entirely established. The overall aim of this thesis was therefore to identify and study immune markers associated with complications in diabetes. Furthermore, we aimed to functionally investigate IL-2/IL-2R signalling in Tregs from patients with different severities of SS. In our first study (paper I) we found that elevated levels of sIL-2R associated with the presence of vascular complications in patients with long-term T1D. Furthermore, we identified single nucleotide polymorphisms (SNP) in the IL2RA gene to be associated with sIL-2R. Finally, we observed a shift from naïve to effector T cells in patients with vascular complications compared with those without, indicating a breakage of immune tolerance, thus allowing an increase in pro-inflammatory T cells. We concluded that IL2RA SNPs may not only affect susceptibility to T1D, but also promote the development of vascular complications possibly by regulating sIL-2R plasma levels and lowering T cell responsiveness. In paper II, we expanded our investigations on the link between sIL-2R and diabetic complications and included patients with different subtypes of diabetes such as type 2 diabetes (T2D). T2D is traditionally considered a non-autoimmune form of diabetes, however there is increasing evidence on immune-related factors involved in the pathogenesis of insulin resistance and T2D. Interestingly, we found that increased plasma sIL-2R was consistently associated with vascular complications, irrespective of the diabetes subtype, suggesting that high sIL-2R can be indicative of disease severity. This notion was further supported by our finding that insulin-dependent patients with T2D had significantly elevated sIL-2R compared with those without insulin treatment. Furthermore, we identified SNPs in the IL2RA gene to be associated with sIL-2R and a vascular complication phenotype in individuals with T2D. Together, these results support a role for sIL-2R and its association with IL2RA SNPs and diabetic complications, not only in T1D, but in other types of diabetes as well. In our third project on SS (paper III), we investigated if IL-2/IL-2R signalling could be compromised in patients with elevated plasma levels of sIL-2R. For this we studied patients with SS and found that particularly patients with a pathologically low salivary flow exhibited highest levels of sIL-2R, which was also associated with seropositivity. Functional studies on Tregs revealed that patients with SS had a reduced IL-2/IL-2R signalling capacity indicating an impaired suppressive activity in those cells. Our data indicated that Tregs have a weakened immunosuppressive function in patients with SS, which could mediate an aggressive lymphocyte infiltration into salivary glands. This in turn induces sicca symptoms, which are associated with higher plasma sIL-2R. Taken together, our findings highlight an association of elevated sIL-2R with disease severity in the autoimmune diseases T1D and SS reflected by the presence of severe vascular complications and pathologic sicca symptoms, respectively. Furthermore, increased sIL-2R levels are also associated with insulin-treated T2D and with vascular complications in general. We believe that circulating sIL-2R can potentially be used as an indicator of diabetes severity and assist in disease monitoring and treatment of complications in autoimmune diseases including diabetes

The E3 SUMO ligase PIASy is a novel interaction partner regulating the activity of diabetes associated hepatocyte nuclear factor-1a

The transcription factor hepatocyte nuclear factor-1α (HNF-1A) is involved in normal pancreas development and function. Rare variants in the HNF1A gene can cause monogenic diabetes, while common variants confer type 2 diabetes risk. The precise mechanisms for regulation of HNF-1A, including the role and function of post-translational modifications, are still largely unknown. Here, we present the first evidence for HNF-1A being a substrate of SUMOylation in cellulo and identify two lysine (K) residues (K205 and K273) as SUMOylation sites. Overexpression of protein inhibitor of activated STAT (PIASγ) represses the transcriptional activity of HNF-1A and is dependent on simultaneous HNF-1A SUMOylation at K205 and K273. Moreover, PIASγ is a novel HNF-1A interaction partner whose expression leads to translocation of HNF-1A to the nuclear periphery. Thus, our findings support that the E3 SUMO ligase PIASγ regulates HNF-1A SUMOylation with functional implications, representing new targets for drug development and precision medicine in diabetes

Guidance for the preparation of neurological management guidelines by EFNS scientific task forces: revised recommendations 2012

This paper is meant to provide guidance to anyone wishing to write a neurological guideline for diagnosis or treatment, and is directed at the Scientist Panels and task forces of the European Federation of Neurological Societies (EFNS). It substitutes the previous guidance paper from 2004. It contains several new aspects: the guidance is now based on a change of the grading system for evidence and for the resulting recommendations, and has adopted The Grading of Recommendations, Assessment, Development and Evaluation system (GRADE). The process of grading the quality of evidence and strength of recommendations can now be improved and made more transparent. The task forces embarking on the development of a guideline must now make clearer and more transparent choices about outcomes considered most relevant when searching the literature and evaluating their findings. Thus, the outcomes chosen will be more critical, more patient-oriented and easier to translate into simple recommendations. This paper also provides updated practical recommendations for planning a guideline task force within the framework of the EFNS. Finally, this paper hopes to find the approval also by the relevant bodies of our future organization, the European Academy of Neurology

The E3 SUMO ligase PIASγ is a novel interaction partner regulating the activity of diabetes associated hepatocyte nuclear factor-1α

The transcription factor hepatocyte nuclear factor-1α (HNF-1A) is involved in normal pancreas development and function. Rare variants in the HNF1A gene can cause monogenic diabetes, while common variants confer type 2 diabetes risk. The precise mechanisms for regulation of HNF-1A, including the role and function of post-translational modifications, are still largely unknown. Here, we present the first evidence for HNF-1A being a substrate of SUMOylation in cellulo and identify two lysine (K) residues (K205 and K273) as SUMOylation sites. Overexpression of protein inhibitor of activated STAT (PIASγ) represses the transcriptional activity of HNF-1A and is dependent on simultaneous HNF-1A SUMOylation at K205 and K273. Moreover, PIASγ is a novel HNF-1A interaction partner whose expression leads to translocation of HNF-1A to the nuclear periphery. Thus, our findings support that the E3 SUMO ligase PIASγ regulates HNF-1A SUMOylation with functional implications, representing new targets for drug development and precision medicine in diabetes

The E3 SUMO ligase PIASy is a novel interaction partner regulating the activity of diabetes associated hepatocyte nuclear factor-1a

The transcription factor hepatocyte nuclear factor-1α (HNF-1A) is involved in normal pancreas development and function. Rare variants in the HNF1A gene can cause monogenic diabetes, while common variants confer type 2 diabetes risk. The precise mechanisms for regulation of HNF-1A, including the role and function of post-translational modifications, are still largely unknown. Here, we present the first evidence for HNF-1A being a substrate of SUMOylation in cellulo and identify two lysine (K) residues (K205 and K273) as SUMOylation sites. Overexpression of protein inhibitor of activated STAT (PIASγ) represses the transcriptional activity of HNF-1A and is dependent on simultaneous HNF-1A SUMOylation at K205 and K273. Moreover, PIASγ is a novel HNF-1A interaction partner whose expression leads to translocation of HNF-1A to the nuclear periphery. Thus, our findings support that the E3 SUMO ligase PIASγ regulates HNF-1A SUMOylation with functional implications, representing new targets for drug development and precision medicine in diabetes

Impaired activation of STAT5 upon IL-2 stimulation in Tregs and elevated sIL-2R in Sjögren’s syndrome

Background Interleukin-2 (IL-2) and the high-affinity IL-2 receptor (IL-2R) are essential for the survival of regulatory T cells (Tregs) which are the main players in immune tolerance and prevention of autoimmune diseases. Sjögren’s syndrome (SS) is a chronic autoimmune disease predominantly affecting women and is characterised by sicca symptoms including oral and ocular dryness. The aim of this study was to investigate an association between IL-2R and Treg function in patients with SS of different severity defined by the salivary flow rate. Methods In a cross-sectional study, we determined plasma soluble IL-2R (sIL-2R) levels in women with SS (n=97) and healthy females (n=50) using ELISA. A subset of those (n=51) was screened for Treg function measured by the STAT5 signalling response to IL-2 using phospho-flow cytometry. Results We found that elevated plasma levels of sIL-2R were positively associated with the severity of SS reflected by a pathologically low salivary flow. Phospho-flow analysis revealed that patients with SS have a significantly lower frequency of pSTAT5+ Tregs upon IL-2 stimulation compared with healthy individuals, while the frequency of Tregs and pSTAT5 in conventional T cells remained unchanged. In addition, we observed more pSTAT5+ Tregs at baseline in patients with SS, which is significantly associated with seropositivity and elevated sIL-2R. Conclusions Our data indicates that Tregs have a weakened immunosuppressive function in patients with SS due to impaired IL-2/IL-2R signalling capacity. This could mediate lymphocytic infiltration into salivary glands inducing sicca symptoms. We believe that sIL-2R could act as a useful indicator for SS and disease severity

Obesity Surgery / Upregulated TNF Expression 1 Year After Bariatric Surgery Reflects a Cachexia-Like State in Subcutaneous Adipose Tissue

Background Adipose tissue dysfunction contributes to obesity-associated chronic diseases. In the first year after bariatric surgery, obese patients significantly improve their metabolic status upon losing weight. We aimed to investigate whether changes in subcutaneous adipose tissue gene expression reflect a restoration of a healthy lean phenotype after bariatric surgery. Methods Thirty-one severely obese patients (BMI 40 kg/m2) were examined before and after surgery. subcutaneous adipose tissue (SAT) was collected during and 1 year after bariatric surgery. SAT from 20 matched lean and overweight patients (BMI < 30 kg/m2) was collected during elective abdominal surgery. Baseline characteristics and SAT gene expression relevant to glucose and lipid metabolism, inflammation, and apoptosis were analyzed. Results After surgery, mean BMI decreased from 46.1 6.3 to 31.1 5.7 kg/m2 and homeostasis model assessment of insulin resistance from 5.4 5.3 to 0.8 0.8. SAT expression of most analyzed inflammatory cytokines, growth factors, and metabolic and cell surface markers was greatly downregulated even compared to the lean cohort. In contrast, gene expression of TNF and CASP3 was significantly upregulated. Elastic net regression analysis showed that fasting glucose levels and CASP3 predicted increased TNF expression in the post-obese group. Conclusions Gene expression patterns in SAT 1 year after bariatric surgery point to a reduced inflammation. The unexpected high TNF expression in SAT of post-obese subjects is most likely not an indicator for inflammation, but rather an indicator for increased lipolysis and adipose tissue catabolism. Notably, after bariatric surgery SAT gene expression reflects a cachexia-like phenotype and differs from the lean state.(VLID)354382

Increased Plasma Soluble Interleukin-2 Receptor Alpha Levels in Patients With Long-Term Type 1 Diabetes With Vascular Complications Associated With IL2RA and PTPN2 Gene Polymorphisms

Type 1 diabetes (T1D) is largely considered an autoimmune disease leading to the destruction of insulin-producing pancreatic beta cells. Further, patients with T1D have 3-4-fold increased risk of developing micro- and macrovascular complications. However, the contribution of immune-related factors contributing to these diabetes complications are poorly understood. Individuals with long-term T1D who do not progress to vascular complications offer a great potential to evaluate end-organ protection. The aim of the present study was to investigate the association of inflammatory protein levels with vascular complications (retinopathy, nephropathy, cardiovascular disease) in individuals with long-term T1D compared to individuals who rapidly progressed to complications. We studied a panel of inflammatory markers in plasma of patients with long-term T1D with (n = 81 and 26) and without (n = 313 and 25) vascular complications from two cross-sectional Scandinavian cohorts (PROLONG and DIALONG) using Luminex technology. A subset of PROLONG individuals (n = 61) was screened for circulating immune cells using multicolor flow cytometry. We found that elevated plasma levels of soluble interleukin-2 receptor alpha (sIL-2R) were positively associated with the complication phenotype. Risk carriers of polymorphisms in the IL2RA and PTPN2 gene region had elevated plasma levels of sIL-2R. In addition, cell surface marker analysis revealed a shift from naive to effector T cells in T1D individuals with vascular complications as compared to those without. In contrast, no difference between the groups was observed either in IL-2R cell surface expression or in regulatory T cell population size. In conclusion, our data indicates that IL2RA and PTPN2 gene variants might increase the risk of developing vascular complications in people with T1D, by affecting sIL-2R plasma levels and potentially lowering T cell responsiveness. Thus, elevated sIL-2R plasma levels may serve as a biomarker in monitoring the risk for developing diabetic complications and thereby improve patient care.Peer reviewe