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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02769-y.

Liver nucleotide biosynthesis is linked to protection from vascular complications in individuals with long-term type 1 diabetes

Identification of biomarkers associated with protection from developing diabetic complications is a prerequisite for an effective prevention and treatment. The aim of the present study was to identify clinical and plasma metabolite markers associated with freedom from vascular complications in people with very long duration of type 1 diabetes (T1D). Individuals with T1D, who despite having longer than 30 years of diabetes duration never developed major macro- or microvascular complications (non-progressors; NP) were compared with those who developed vascular complications within 25 years from diabetes onset (rapid progressors; RP) in the Scandinavian PROLONG (n = 385) and DIALONG (n = 71) cohorts. The DIALONG study also included 75 healthy controls. Plasma metabolites were measured using gas and/or liquid chromatography coupled to mass spectrometry. Lower hepatic fatty liver indices were significant common feature characterized NPs in both studies. Higher insulin sensitivity and residual ß-cell function (C-peptide) were also associated with NPs in PROLONG. Protection from diabetic complications was associated with lower levels of the glycolytic metabolite pyruvate and APOCIII in PROLONG, and with lower levels of thiamine monophosphate and erythritol, a cofactor and intermediate product in the pentose phosphate pathway as well as higher phenylalanine, glycine and serine in DIALONG. Furthermore, T1D individuals showed elevated levels of picolinic acid as compared to the healthy individuals. The present findings suggest a potential beneficial shunting of glycolytic substrates towards the pentose phosphate and one carbon metabolism pathways to promote nucleotide biosynthesis in the liver. These processes might be linked to higher insulin sensitivity and lower liver fat content, and might represent a mechanism for protection from vascular complications in individuals with long-term T1D.

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 β 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 naïve 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.

Serum Myostatin is Upregulated in Obesity and Correlates with Insulin Resistance in Humans

Obesity and type 2 diabetes mellitus have reached an epidemic level, thus novel treatment concepts need to be identified. Myostatin, a myokine known for restraining skeletal muscle growth, has been associated with the development of insulin resistance and type 2 diabetes mellitus. Yet, little is known about the regulation of myostatin in human obesity and insulin resistance. We aimed to investigate the regulation of myostatin in obesity and uncover potential associations between myostatin, metabolic markers and insulin resistance/sensitivity indices. Circulating active myostatin concentration was measured in the serum of twenty-eight severely obese non-diabetic patients compared to a sex and age matched lean and overweight control group (n=22). Insulin resistance/sensitivity was assessed in the obese group. Skeletal muscle and adipose tissue specimens from the obese group were collected during elective bariatric surgery. Adipose tissue samples from lean and overweight subjects were collected during elective abdominal surgery. Myostatin concentration was increased in obese compared to lean individuals, while myostatin adipose tissue expression did not differ. Muscle myostatin gene expression strongly correlated with expression of metabolic genes such as IRS1, PGC1α, SREBF1. Circulating myostatin concentration correlated positively with insulin resistance indices and negatively with insulin sensitivity indices. The best correlation was obtained for the oral glucose insulin sensitivity index. Our results point to an interesting correlation between myostatin and insulin resistance/sensitivity in humans, and emphasize its need for further evaluation as a pharmacological target in the prevention and treatment of obesity-associated metabolic complications.

Nuclear import of glucokinase in pancreatic beta-cells is mediated by a nuclear localization signal and modulated by SUMOylation

The localization of glucokinase in pancreatic beta-cell nuclei is a controversial issue. Although previous reports suggest such a localization, the mechanism for its import has so far not been identified. Using immunofluorescence, subcellular fractionation and mass spectrometry, we present evidence in support of glucokinase localization in beta-cell nuclei of human and mouse pancreatic sections, as well as in human and mouse isolated islets, and murine MIN6 cells. We have identified a conserved, seven-residue nuclear localization signal (³⁰LKKVMRR³⁶) in the human enzyme. Substituting the residues KK^31,32 and RR^35,36 with AA led to a loss of its nuclear localization in transfected cells. Furthermore, our data indicates that SUMOylation of glucokinase modulates its nuclear import, while high glucose concentrations do not significantly alter the enzyme nuclear/cytosolic ratio. Thus, for the first time, we provide data in support of a nuclear import of glucokinase mediated by a redundant mechanism, involving a nuclear localization signal, and which is modulated by its SUMOylation. These findings add new knowledge to the functional role of glucokinase in the pancreatic beta-cell.

Alcohol withdrawal syndrome: mechanisms, manifestations, and management

The alcohol withdrawal syndrome is a well‐known condition occurring after intentional or unintentional abrupt cessation of heavy/constant drinking in patients suffering from alcohol use disorders (AUDs). AUDs are common in neurological departments with patients admitted for coma, epileptic seizures, dementia, polyneuropathy, and gait disturbances. Nonetheless, diagnosis and treatment are often delayed until dramatic symptoms occur. The purpose of this review is to increase the awareness of the early clinical manifestations of AWS and the appropriate identification and management of this important condition in a neurological setting.

EAN guidelines on central neurostimulation therapy in chronic pain conditions

BACKGROUND AND PURPOSE

Our aim was to update previous European Federation of Neurological Societies guidelines on neurostimulation for neuropathic pain, expanding the search to new techniques and to chronic pain conditions other than neuropathic pain, and assessing the evidence with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

METHODS

A systematic review and meta-analysis of trials published between 2006 and December 2014 was conducted. Pain conditions included neuropathic pain, fibromyalgia, complex regional pain syndrome (CRPS) type I and post-surgical chronic back and leg pain (CBLP). Spinal cord stimulation (SCS), deep brain stimulation (DBS), epidural motor cortex stimulation (MCS), repetitive transcranial magnetic stimulation (rTMS) and transcranial direct electrical stimulation (tDCS) of the primary motor cortex (M1) or dorsolateral prefrontal cortex (DLPFC) were assessed. The GRADE system was used to assess quality of evidence and propose recommendations.

RESULTS

The following recommendations were reached: 'weak' for SCS added to conventional medical management in diabetic painful neuropathy, CBLP and CRPS, for SCS versus reoperation in CBLP, for MCS in neuropathic pain, for rTMS of M1 in neuropathic pain and fibromyalgia and for tDCS of M1 in neuropathic pain; 'inconclusive' for DBS in neuropathic pain, rTMS and tDCS of the DLPFC, and for motor cortex tDCS in fibromyalgia and spinal cord injury pain.

CONCLUSIONS

Given the poor to moderate quality of evidence identified by this review, future large-scale multicentre studies of non-invasive and invasive neurostimulation are encouraged. The collection of higher quality evidence of the predictive factors for the efficacy of these techniques, such as the duration, quality and severity of pain, is also recommended.

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.