Changes of regulatory T cells, transforming growth factor-beta and interleukin-10 in patients with type 1 diabetes mellitus: A systematic review and meta-analysis

Effects of diabetes mellitus and glycemic traits on cardiovascular morpho-functional phenotypes

BACKGROUND

The effects of diabetes on the cardiac and aortic structure and function remain unclear. Detecting and intervening these variations early is crucial for the prevention and management of complications. Cardiovascular magnetic resonance imaging-derived traits are established endophenotypes and serve as precise, early-detection, noninvasive clinical risk biomarkers. We conducted a Mendelian randomization (MR) study to examine the association between two types of diabetes, four glycemic traits, and preclinical endophenotypes of cardiac and aortic structure and function.

METHODS

Independent genetic variants significantly associated with type 1 diabetes, type 2 diabetes, fasting insulin (FIns), fasting glucose (FGlu), 2 h-glucose post-challenge (2hGlu), and glycated hemoglobin (HbA1c) were selected as instrumental variables. The 96 cardiovascular magnetic resonance imaging traits came from six independent genome-wide association studies. These traits serve as preclinical endophenotypes and offer an early indication of the structure and function of the four cardiac chambers and two aortic sections. The primary analysis was performed using MR with the inverse-variance weighted method. Confirmation was achieved through Steiger filtering and testing to determine the causal direction. Sensitivity analyses were conducted using the weighted median, MR-Egger, and MR-PRESSO methods. Additionally, multivariable MR was used to adjust for potential effects associated with body mass index.

RESULTS

Genetic susceptibility to type 1 diabetes was associated with increased ascending aortic distensibility. Conversely, type 2 diabetes showed a correlation with a reduced diameter and areas of the ascending aorta, as well as decreased distensibility of the descending aorta. Genetically predicted higher levels of FGlu and HbA1c were correlated with a decrease in diameter and areas of the ascending aorta. Furthermore, higher 2hGlu levels predominantly showed association with a reduced diameter of both the ascending and descending aorta. Higher FIns levels corresponded to increased regional myocardial-wall thicknesses at end-diastole, global myocardial-wall thickness at end-diastole, and regional peak circumferential strain of the left ventricle.

CONCLUSIONS

This study provides evidence that diabetes and glycemic traits have a causal relationship with cardiac and aortic structural and functional remodeling, highlighting the importance of intensive glucose-lowering for primary prevention of cardiovascular diseases.

Regulatory T cells in the peripheral blood of women with gestational diabetes: a systematic review and meta-analysis

Background

Gestational diabetes (GDM) affects approximately 14% of pregnancies globally and is associated with short- and long-term complications for both the mother and child. In addition, GDM has been linked to chronic low-grade inflammation with recent research indicating a potential immune dysregulation in pathophysiology and a disparity in regulatory T cells.

Objective

This systematic review and meta-analysis aimed to determine whether there is an association between GDM and the level of Tregs in the peripheral blood.

Methods

Literature searches were conducted in PubMed, Embase, and Ovid between the 7th and 14th of February 2022. The inclusion criteria were any original studies published in the English language, measuring differentiated Tregs in women with GDM compared with glucose-tolerant pregnant women. Meta-analysis was performed between comparable Treg markers. Statistical tests were used to quantify heterogeneity: τ 2, χ 2, and I 2. Study quality was assessed using a modified version of the Newcastle-Ottawa scale.

Results

The search yielded 223 results: eight studies were included in the review and seven in the meta-analysis (GDM = 228, control = 286). Analysis of Tregs across all trimesters showed significantly lower Treg numbers in women with GDM (SMD, -0.76; 95% CI, -1.37, -0.15; I 2 = 90%). This was reflected in the analysis by specific Treg markers (SMD -0.55; 95% CI, -1.04, -0.07; I 2 = 83%; third trimester, five studies). Non-significant differences were found within subgroups (differentiated by CD4+FoxP3+, CD4+CD127-, and CD4+CD127-FoxP3) of both analyses.

Conclusion

GDM is associated with lower Treg numbers in the peripheral maternal blood. In early pregnancy, there is clinical potential to use Treg levels as a predictive tool for the subsequent development of GDM. There is also a potential therapeutic intervention to prevent the development of GDM by increasing Treg populations. However, the precise mechanism by which Tregs mediate GDM remains unclear.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022309796.

Expanding role of CXCR2 and therapeutic potential of CXCR2 antagonists in inflammatory diseases and cancers

C-X-C motif chemokine receptor 2 (CXCR2) is G protein-coupled receptor (GPCR) and plays important roles in various inflammatory diseases and cancers, including chronic obstructive pulmonary disease (COPD), atherosclerosis, asthma, and pancreatic cancer. Upregulation of CXCR2 is closely associated with the migration of neutrophils and monocytes. To date, many small-molecule CXCR2 antagonists have entered clinical trials, showing favorable safety and therapeutic effects. Hence, we provide an overview containing the discovery history, protein structure, signaling pathways, biological functions, structure-activity relationships and clinical significance of CXCR2 antagonists in inflammatory diseases and cancers. According to the latest development and recent clinical progress of CXCR2 small molecule antagonists, we speculated that CXCR2 can be used as a biomarker and a new target for diabetes and that CXCR2 antagonists may also attenuate lung injury in coronavirus disease 2019 (COVID-19).

Changes of macrophage and CD4+ T cell in inflammatory response in type 1 diabetic mice

Immune cells play an important role in the development of inflammation in type 1 diabetes mellitus, so we want to explore the changes of CD4+ T cells and macrophages in vivo, which can provide an experimental basis for immunotherapy based on CD4+ T cells and macrophages. The intraperitoneal injection of streptozocin was used to induce a type 1 diabetes mellitus mouse model; the blood glucose, body weight, and the expression of inflammatory factors in the kidney were measured. Immunohistochemistry was applied to determine and analyze the infiltration of CD4+ T cells and macrophages in the spleen, pancreas, and kidney. The subtypes of macrophages in the kidney and CD4+ T cells in the spleen were analyzed by flow cytometry. Our study suggests that CD4+ T cells and macrophages increase, while the inflammatory immune response system is activated in the development of T1DM. CD4+ T cells positively correlated with macrophages in the pancreas and kidney of T1DM. CD4+ T cells turn to pro-inflammatory subtypes in the spleen of T1DM, while macrophages turn to pro-inflammatory subtypes in the kidney of T1DM. Therefore, regulation of CD4+ T cells and macrophages may be a potential target for T1DM and kidney complications.

Level of physical activity and gene expression of IL-10 and TNF-α in children and adolescents with Type 1 diabetes

AIMS

The gene expressions of IL-10 and TNF-α have been identified as important factors of the clinical condition in type I diabetes mellitus (DM1). However, the effect of physical exercise on the expression of these markers is poorly understood. Our objective was to evaluate the relationship between the level of physical activity (LPA) and the gene expressions of IL-10 and TNF-α, as the relationship with glycemic control and insulin reserve in children and adolescents with DM1.

METHODS

108 participants (1-23 years), were divided into 4 groups: DM1 with ketoacidosis (KETO) (n = 15); Decompensated DM1 (DM1d) (n = 32); Compensated DM1 (DM1c) (n = 30); and healthy control (C) (n = 30). The level of physical activity (LPA) was classified as low active, active, and very active. So evaluated Fasting blood glucose, HbA1c, C-peptide, and gene expressions of IL-10 and TNF-α.

RESULTS

The increase in the level of physical activity significantly affected the expression of TNF-α in the DMd and C groups. The increase in LPA from low to active reduced the gene expression of IL-10; however, the increase in NAF from active to very active was associated with an increase in IL-10 gene expression. A very active LPA contributes to reducing HbA1c and an increase in C-peptide in the KETO group.

CONCLUSION

The increase in LPA demonstrated a significant effect on the improvement of IL-10 and TNF-α gene expression in the KETO and DMd groups; however, in the KETO group, improvements were also observed in the percentage of HbA1C and C-peptide.

The Peripheral Immune System and Traumatic Brain Injury: Insight into the role of T-helper cells

Emerging evidence suggests that immune-inflammatory processes are key elements in the physiopathological events associated with traumatic brain injury (TBI). TBI is followed by T-cell-specific immunological changes involving several subsets of T-helper cells and the cytokines they produce; these processes can have opposite effects depending on the disease course and cytokine concentrations. Efforts are underway to identify the T-helper cells and cytokine profiles associated with prognosis. These predictors may eventually serve as effective treatment targets to decrease morbidity and mortality and to improve the management of TBI patients. Here, we review the immunological response to TBI, the possible molecular mechanisms of this response, and therapeutic strategies to address it.

Regulatory T Cells and Diabetes Mellitus

Immune system dysfunction causes dysregulation of immune homeostasis, which in turn leads to autoimmune diseases. Regulatory T cells (Tregs) are a specialized T cell subpopulation that maintain peripheral tolerance and immune homeostasis. Diabetic patients are at an increased risk of developing cardiovascular diseases; thus, in terms of coronary risk, diabetes mellitus (DM) is considered coronary heart disease equivalent. Accumulating evidence indicates that Tregs play an important role in protecting against the development of various cardiovascular diseases. In this review, we provide an overview of the role of Tregs in the pathogenesis of DM, including type 1 DM, type 2 DM, latent autoimmune diabetes of adults, and gestational DM. In addition, we discuss the role of Tregs in diabetic complications, including cardiovascular diseases, nephropathy, neuropathy, and retinopathy. Tregs play a beneficial role in the pathogenesis of DM and diabetic complications, although the precise molecular mechanisms underlying the protective effect of Tregs against DM are still obscure. Collectively, modification of Tregs may provide a promising and novel future strategy for the prevention and therapy of DM and diabetic complications.

SARS-CoV-2-mediated immune system activation and potential application in immunotherapy

Although novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-mediated pulmonary inflammation has recently attracted great attention, its pathology and pathogenesis are not clear. Notably, due to both its high infective and pathogenicity, SARS-CoV-2 infection may cause a severe sometimes fatal respiratory disease. A specific vaccine, which relies on the analysis of SARS-CoV-2 structural protein-derived antigenic peptides, is indispensable for restraining the spread and reducing the mortality of SARS-CoV-2. SARS-CoV-2 infections activate cytototxic, myeloid-derived suppressor cells, dendritic cells, macrophages, as well as natural killer, B, helper T, and regulatory T cells, thus further stimulating innate and antigen-specific immune responses. Nevertheless, many immune effector cells cause hyperinflammation and pulmonary immunopathology by releasing proinflammatory cytokines and chemokines, including interferon (IFN)-α, IFN-β, IFN-γ, monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1A, MIP1B, interleukin (IL)-1, IL-2, IL-4, IL-6, IL-7, IL-8, IL-9, IL-12, IL-17, and IL-18, platelet-derived growth factor, fibroblast growth factor, tumor necrosis factor-α, and induced protein 10. Interestingly, related products derived from SARS-CoV-2 are likely to trigger immune evasion. Therefore, investigating SARS-CoV-2-specific vaccines, blocking immunopathology, and prohibiting immune evasion are urgently required for treating SARS-CoV-2 infection. In this review, we emphatically illuminated the development of a SARS-CoV-2-specific vaccine based on the analysis of epitopes, also expounding the molecular mechanisms of SARS-CoV-2-mediated cytokine release syndrome. Furthermore, we comprehensively discussed SARS-CoV-2-associated immune evasion and lung immunopathology. Lastly, potential therapeutic strategies against SARS-CoV-2 were explored.

Thymoquinone in autoimmune diseases: Therapeutic potential and molecular mechanisms

Autoimmune diseases (AUDs) are a multifactorial disease, among which rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis are more prevalent. Several anti-inflammatory, biologics, and AUD-modifying drugs are found effective against them, but their repeated use are associated with various adverse effects. In this review article, we have focused on the regulation of inflammatory molecules, molecular signaling pathways, immune cells, and epigenetics by natural product thymoquinone on AUDs. Studies indicate that thymoquinone can regulate inflammatory molecules including interferons, interleukins, tumor necrosis factor-α (TNF-α), oxidative stress, regulatory T cells, and various signaling pathways such as nuclear factor kappa beta (NF-κβ), janus kinase/signal transduction and activator of transcription (JAK-STAT), mitogen-activated protein kinase (MAPK) at the molecular level and epigenetic alteration. As these molecules and signaling pathways with defective immune function play an important role in AUD development, controlling these molecules and deregulated molecular mechanism is a significant feature of AUD therapeutics. Interestingly thymoquinone is reported to possess all these potential. This article reviewed the deregulated mechanism of AUDs, and the action of thymoquinone on inflammatory molecules, immune cells, signaling pathways, and epigenetic machinery. Thymoquinone can be regarded as a potential drug candidate for AUD treatment.

Gene Expression Analysis of the Pre-Diabetic Pancreas to Identify Pathogenic Mechanisms and Biomarkers of Type 1 Diabetes

Type 1 Diabetes (T1D) occurs as a result of the autoimmune destruction of pancreatic β-cells by self-reactive T cells. The etiology of this disease is complex and difficult to study due to a lack of disease-relevant tissues from pre-diabetic individuals. In this study, we performed gene expression analysis on human pancreas tissues obtained from the Network of Pancreatic Organ Donors with Diabetes (nPOD), and showed that 155 genes were differentially expressed by ≥2-fold in the pancreata of autoantibody-positive (AA+) at-risk individuals compared to healthy controls. Only 48 of these genes remained changed by ≥2-fold in the pancreata of established T1D patients. Pathway analysis of these genes showed a significant association with various immune pathways. We were able to validate the differential expression of eight disease-relevant genes by QPCR analysis: A significant upregulation of CADM2, and downregulation of TRPM5, CRH, PDK4, ANGPL4, CLEC4D, RSG16, and FCGR2B was confirmed in the pancreata of AA+ individuals versus controls. Studies have already implicated FCGR2B in the pathogenesis of disease in non-obese diabetic (NOD) mice. Here we showed that CADM2, TRPM5, PDK4, and ANGPL4 were similarly changed in the pancreata of pre-diabetic 12-week-old NOD mice compared to NOD.B10 controls, suggesting a possible role for these genes in the pathogenesis of both T1D and NOD disease. The loss of the leukocyte-specific gene, FCGR2B, in the pancreata of AA+ individuals, is particularly interesting, as it may serve as a potential whole blood biomarker of disease progression. To test this, we quantified FCGR2B expression in peripheral blood samples of T1D patients, and AA+ and AA- first-degree relatives of T1D patients enrolled in the TrialNet Pathway to Prevention study. We showed that FCGR2B was significantly reduced in the peripheral blood of AA+ individuals compared to AA- controls. Together, these findings demonstrate that gene expression analysis of pancreatic tissue and peripheral blood samples can be used to identify disease-relevant genes and pathways and potential biomarkers of disease progression in T1D.

Systemic Inflammation Precedes Microalbuminuria in Diabetes

Aim

The aim of the case-control study was to investigate if serum biomarkers indicative of vascular inflammation and endothelial dysfunction can predict the development of microalbuminuria in patients with diabetes mellitus type 2.

Methods

Among participants enrolled in the ROADMAP (Randomized Olmesartan And Diabetes MicroAlbuminuria Prevention) and observational follow-up (OFU) studies, a panel of 15 serum biomarkers was quantified from samples obtained at initiation of the study and tested for associations with the development of new-onset microalbuminuria during follow-up. A case-control study was conducted with inclusion of 172 patients with microalbuminuria and 188 matched controls. Nonparametric inferential, nonlinear regression, mediation, and bootstrapping statistical methods were used for the analysis.

Results

The median follow-up time was 37 months. At baseline, mean concentrations of C-X-C motif chemokine ligand 16 (CXCL-16), transforming growth factor (TGF)–β1 and angiopoietin-2 were higher in patients with subsequent microalbuminuria. In the multivariate analysis, after adjustment for age, sex, body mass index, glycated hemoglobin, duration of diabetes, low-density lipoprotein (LDL), smoking status, blood pressure, baseline urine albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), time of follow-up and cardiovascular disease, CXCL-16 (odds ratio [OR] 2.60, 95% confidence interval [CI] 1.71–3.96), angiopoietin-2 (OR 1.50, 95% CI 1.14–1.98) and TGF-β1 (OR 1.03, 95% CI 1.01–1.04) remained significant predictors of new-onset microalbuminuria (P < 0.001). Inclusion of these biomarkers in conventional clinical risk models for prediction of microalbuminuria increased the area under the curve (AUC) from 0.638 to 0.760 (P < 0.001).

Conclusion

In patients with type 2 diabetes, elevated plasma levels of CXCL-16, angiopoietin-2, and TGF-β1 are independently predictive of microalbuminuria. Thus, these serum markers improve renal risk models beyond established clinical risk factors.

Using DPP-4 inhibitors to modulate beta cell function in type 1 diabetes and in the treatment of diabetic kidney disease

INTRODUCTION

DPP-4 inhibitors have pleomorphic effects that extend beyond the anti-hyperglycemic labeled use of the drug. DPP-4 inhibitors have demonstrated promising renal protective effects in T2DM and T1DM and protective effects against immune destruction of pancreatic beta-cells in T1DM.

AREAS COVERED

The efficacy of DPP-4 inhibitors in the treatment of diabetic kidney disease and possible adjunct with insulin in the treatment of T1DM to preserve beta-cell function. Pertinent literature was identified through Medline, PubMed and ClinicalTrials.gov (1997-November 2018) using the search terms T1DM, sitagliptin, vildagliptin, linagliptin, beta-cell function, diabetic nephropathy. Only articles are written in the English language, and clinical trials evaluating human subjects were used.

EXPERT OPINION

DPP-4 inhibitors can be used safely in patients with diabetic kidney disease and do not appear to exacerbate existing diabetic nephropathy. Linagliptin reduces albuminuria and protects renal endothelium from the deleterious effects of hyperglycemia. The effects of DPP-4 inhibitors on preserving beta-cell function in certain subtypes of T1DM [e.g. Latent Autoimmune Diabetes in Adult (LADA) and Slowly Progressive Type 1 Diabetes (SPIDDM)] are encouraging and show promise.

Bacterial respiratory tract inflammation in neonatal rat model is attenuated by benzofuran through inhibition of GATA3

The current study was aimed to investigate the effect of benzofuran on asthma neonatal rat model. Twenty-five neonatal rats were assigned into five groups; Normal control, untreated, 1 mg/kg, 8 mg/kg and 10 mg/kg treatment groups. Methacholine was administered orally to the rats of untreated and treatment groups. Animals in the normal control group were given PBS as a vehicle. FlexiVent system employing a computer-controlled mouse ventilator along with respiratory mechanics was used for the analysis of airway resistance in the rats. Cytokine level and IFN-γ in the rat serum samples was performed by ELISA in accordance with the instructions of manufacturer. Methacholine administration into the rats caused a marked increase in lung airway resistance. However, treatment with 8 and 10 mg/kg doses of benzofuran led to marked decrease in the airway resistance. Benzofuran treatment prevented accumulation of macrophages and inflammatory cells in the lung airways. Inhibition of inflammation in methacholine administered rats by benzofuran was also confirmed by hematoxylin & eosin-staining. Examination of the rat serum showed significantly higher level of Th2 cytokines (IL-4, -5 and -13) in the untreated rats. However, treatment of methacholine administered rats with benzofuran significantly inhibited Th2 cytokine expression. The level of IFN-γ was increased by benzofuran treatment in methacholine administered rats. In methacholine administered rats the level of IgE was markedly higher however treatment of asthma rats with benzofuran inhibited up-regulation of IgE significantly. The expression of T-bet is decreased and that of GATA-3 is increased by methacholine administration in the rat lungs. Benzofuran treatment of methacholine administered rats prevented reduction in T-bet and up-regulation of GATA-3 expression in the rat lungs. The effect of benzofuran was significant at the doses of 8 and 10 mg/kg and non-significant at 1 mg/kg. These finding suggest that benzofuran inhibits expression of dominant T-helper 2 cytokines through targeting GATA-binding protein 3 transcription factor. Thus benzofuran can be of therapeutic importance for the treatment of asthma.

Response of regulatory T cells to classic heat stroke in mice

Systemic inflammatory response syndrome (SIRS) is an important process associated with the pathogenesis of multiple organ failure resulting from heat stroke (HS). Alterations in the levels of circulating cytokines during the progression of SIRS have been well established. However, only a small number of studies have demonstrated the responses of lymphocytes during HS, and no studies have investigated immune-regulatory cells, such as regulatory T cells (Tregs). Tregs have been revealed to be important in numerous inflammation-associated diseases, and have exhibited promising therapeutic effects in both experimental and clinical trials. In the present study, the splenic Treg response in a classic HS mouse model was investigated, and the results demonstrated that total numbers of splenic Tregs were significantly decreased at 0, 24 and 72 h time intervals post-heat stress. Furthermore, the immunosuppressive capacity of splenic Tregs on cluster of differentiation (CD)4⁺T cell expansion was revealed to be suppressed following heat stress. In addition, HS was demonstrated to downregulate the expression levels of surface inhibitory molecules (CD39, CD73 and cytotoxic T-lymphocyte associated protein 4), as well as anti-inflammatory cytokines [interleukin (IL)-10, transforming growth factor-β and IL-35], in Tregs. It was hypothesized that the aforementioned Treg responses may contribute to SIRS during HS. To the best of our knowledge, the present study is the first study to investigate the response of Tregs to HS, and the results demonstrated that there were significant alterations regarding to the total number, and function, of splenic Tregs, as well as the expression levels of inhibitory surface molecules and secretory cytokines. These results may highlight a novel mechanism underlying the pathogenesis of HS, as well as identify a potential therapeutic target for SIRS in patients suffering from HS.

Dipeptidyl peptidase-4(DPP-4) inhibitors: promising new agents for autoimmune diabetes

Dipeptidyl peptidase-4 (DPP-4) inhibitors constitute a novel class of anti-diabetic agents confirmed to improve glycemic control and preserve β-cell function in type 2 diabetes. Three major large-scale studies, EXAMINE, SAVOR-TIMI 53, and TECOS, have confirmed the cardiovascular safety profile of DPP-4 inhibitors. Based on these results, DPP-4 inhibitors have gained widespread use in type 2 diabetes treatment. It is currently unknown, however, whether DPP-4 inhibitors have similar therapeutic efficacy against autoimmune diabetes. Several in vitro and in vivo studies have addressed this issue, but the results remain controversial. In this review, we summarize experimental findings and preliminary clinical trial results, and identify potentially effective immune modulation targets of DPP-4 inhibitors for autoimmune diabetes.

TRIF deficiency protects non-obese diabetic mice from type 1 diabetes by modulating the gut microbiota and dendritic cells

The incidence of type 1 diabetes (T1D) is determined by both genetic and environmental factors. In recent years, the gut microbiota have been identified to be an important environmental factor that could modify diabetes susceptibility. We have previously shown that Myeloid differentiation primary response gene 88 (MyD88), a major adaptor protein downstream of most innate immune Toll-like receptor (TLR) signaling, is important for mediating diabetes susceptibility in the non-obese diabetic (NOD) mouse model of human T1D. Here we report the role of TIR-domain-containing adapter-inducing interferon-β (TRIF) in T1D development, as TRIF is an important adaptor protein downstream of TLR3 and TLR4 signaling. We found that TRIF-deficient (TRIF^-/-) NOD mice were protected from development of diabetes, but only when housed with TRIF-deficient (TRIF^-/-) NOD mice. When housed with TRIF-sufficient wild type (WT, i.e., TRIF^+/+) NOD mice, the mice developed diabetes. We further investigated the gut microbiota as a potential cause for the altered diabetes development. Interestingly, TRIF^-/-NOD mice had a different microbiota composition compared to WT NOD mice, only if they were housed with TRIF^-/-NOD mice. However, the composition of gut microbiota in the TRIF^-/-NOD mice was indistinguishable from WT NOD mice, if they were housed with WT NOD mice. The difference in the gut microbiota in TRIF^-/-NOD mice, due to cohousing, accorded with the diabetes development in TRIF^-/-NOD mice. Comparing the gut microbiota in TRIF^-/- and WT NOD mice, we identified changes in percentage of Sutterella, Rikenella and Turicibacter species. Moreover, bacteria from WT NOD mice induced significantly stronger inflammatory immune responses in vitro compared to those from TRIF^-/-NOD mice. Further immunological analysis revealed impaired function of dendritic cells and reduced T cell activation and proliferation in TRIF^-/-NOD mice. Our data show that TRIF-deficiency protects NOD mice from diabetes development through alteration of the gut microbiota and reduced immune cell activation; however, that protection is over-ridden upon exposure to WT NOD bacteria. Therefore exposure to different microbiota can modify disease susceptibility determined by genetic factors related to innate immunity.

The molecular basis of immune regulation in autoimmunity

Autoimmune diseases can be triggered and modulated by various molecular and cellular characteristics. The mechanisms of autoimmunity and the pathogenesis of autoimmune diseases have been investigated for several decades. It is well accepted that autoimmunity is caused by dysregulated/dysfunctional immune susceptible genes and environmental factors. There are multiple physiological mechanisms that regulate and control self-reactivity, but which can also lead to tolerance breakdown when in defect. The majority of autoreactive T or B cells are eliminated during the development of central tolerance by negative selection. Regulatory cells such as Tregs (regulatory T) and MSCs (mesenchymal stem cells), and molecules such as CTLA-4 (cytotoxic T-lymphocyte associated antigen 4) and IL (interleukin) 10 (IL-10), help to eliminate autoreactive cells that escaped to the periphery in order to prevent development of autoimmunity. Knowledge of the molecular basis of immune regulation is needed to further our understanding of the underlying mechanisms of loss of tolerance in autoimmune diseases and pave the way for the development of more effective, specific, and safer therapeutic interventions.

Role of PIM2 in allergic asthma

T cell-associated inflammation, particularly type 2 inflammation, has an important role in asthma pathogenesis, which is suppressed by regulatory T cells (Tregs). Proviral integration site for Moloney murine leukemia virus 2 (PIM2), a member off the serine/threonine kinase family, promotes the growth and survival of T cells and influences the function of Treg cells. However, whether PIM2 affects asthma pathogenesis remains unclear. Peripheral blood mononuclear cells and Treg cells from asthmatic and healthy subjects were obtained, and the expression level of PIM2 was measured by reverse transcription-quantitative polymerase chain reaction and immunocytochemistry. In addition, BALB/c female mice sensitized and challenged by ovalbumin were used as an asthma model, and PIM2 inhibitor was injected during the challenge period to observe the effect of PIM2 on asthma. The asthma symptoms were recorded, and airway hyper-responsiveness (AHR), expression levels of cytokines in the serum or bronchoalveolar lavage fluid (BALF), and the number of BALF leukocytes were evaluated. In addition, hematoxylin and eosin staining and immunohistochemistry of lung tissues was performed. The results demonstrated that PIM2 was overexpressed in patients with asthma in natural Treg cells. Inhibition of PIM2 attenuated asthma symptoms, and improved AHR and airway inflammation compared with asthmatic mice without inhibition of PIM2. In addition, expression levels of interleukin (IL)-10 and forkhead box protein 3 (FOXP3) in BALF were increased following PIM2 inhibition (IL-10, 470.3±21.78 vs. 533.7±25.55 pg/ml, P<0.05; FOXP3, 259±4.68 vs. 279.3±3.68 pg/ml; asthma and PIM2 inhibition groups, respectively; P<0.05). In conclusion, PIM2 may exhibit an important role in asthma pathogenesis and exacerbate AHR, airway inflammation and asthma symptoms. These effects of PIM2 may be dependent on Treg cells and the secretion of IL-10 by Tregs. The results of the present study suggest that PIM2 may be a potential target molecule for asthma treatment.

Changes of transforming growth factor beta 1 in patients with type 2 diabetes and diabetic nephropathy: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

The existing evidence indicates increased levels of transforming growth factor beta 1 (TGF-β1) in patients with type 2 diabetes mellitus (T2DM) and those with type 2 diabetic nephropathy (T2DN); yet no meta-analysis displays a reliable result. Here we conducted a meta-analysis to evaluate characteristic changes of TGF-β1 in T2DM and diabetic nephropathy.

METHODS

A systematic search was conducted for eligible studies, which reported the association of TGF-β1 withT2DM and T2DN patients, in PubMed, Wangfang, Chinese-Cqvip, and China National Knowledge Infrastructure database, from February 1, 1991 to December 15, 2015. The association of serum and urine TGF-β1 in T2DM and T2DN patients should be evaluated in case-control studies. The Newcastle-Ottawa Scale was used to access the quality of the included studies, and pooling data were synthesized as standard mean difference (SMD) and 95% confidence interval (CI). The collected data were synthesized according to Cochrane Handbook for Systematic Reviews criteria. Subgroup analysis was conducted by albuminuria and ethnicity. Regression analysis and sensitivity analysis were used to explore the sources of heterogeneity. Publication bias was judged by the Egger test.

RESULTS

Sixty-three case-control studies of 364 T2DM patients (1604 T2DN patients) and 2100 healthy controls were included for meta-analysis. Compared with the controls, the cases had increased TGF-β1 levels in both serum (T2DM: SMD 1.78 μg/L; 95% CI 0.98-2.59, P < .001; T2DN: SMD 4.70 μg/L, 95% CI 3.55-5.85, P < .001) and urine samples (T2DM: SMD 1.27 pg/mg.creatinine, 95% CI 0.16-2.38, P < .001; SMD 1.19 ng/L, 95% CI 0.77-1.62, P < .001; T2DN: SMD 3.14 pg/mg.creatinine, 95% CI 2.15-4.13, P < .001; SMD 4.50 ng/L, 95% CI 3.16-5.83, P < .001). The increase of serum TGF-β1 persisted in patients with either microalbuminuria or macroalbuminuria (all P < .001) in Chinese and non-Chinese population. High heterogeneity exists in some comparisons and small-sample studies.

CONCLUSIONS

Patients with T2DM and those with albuminuria, Chinese or non-Chinese, had increased serum and urine TGF-β1 levels.

Sitagliptin inhibit human lymphocytes proliferation and Th1/Th17 differentiation in vitro

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic agents that are widely used in clinical practice to improve glycemic control in patients with type 2 diabetes. DPP-4 is also known as lymphocyte cell surface protein, CD26, and plays an important role in T-cell immunity. Recent studies suggest that DPP-4 inhibitors improve beta-cell function and attenuate autoimmunity in type 1 diabetic mouse models. To investigate the direct effect of DPP4 in immune response, human peripheral blood mononuclear cells (PBMC) from healthy volunteers were obtained by Ficoll gradient and cultivated in the absence (control) or presence of phytohemagglutinin (PHA), or stimulated with PHA and treated with sitagliptin. The immune modulation mechanisms analyzed were: cell proliferation, by MTT assay; cytokine quantification by ELISA or cytometric bead array (CBA), Th1/Th2/Th17 phenotyping by flow cytometric analysis and CD26 gene expression by real time PCR. The results showed that sitagliptin treatment inhibited the proliferation of PBMC-PHA stimulated cells in a dose dependent manner and decreased CD26 expression by these cells, suggesting that sitagliptin may interfere in CD26 expression, dimerization and cell signaling. Sitagliptin treatment not only inhibited IL-10 (p<0.05) and IFN-gamma (p=0.07) cytokines, but also completely abolish IL-6 expression by PBMCs (p<0.001). On the other hand, IL-4 were secreted in culture supernatants from sitagliptin treated cells. A statistically significant increase (p<0.05) in the ratio of TGF-beta/proliferation index after sitagliptin treatment (2627.97±1351.65), when comparing to untreated cells (646.28±376.94), was also demonstrated, indicating higher TGF-beta1 production by viable cells in cultures. Sitagliptin treatment induced a significantly (p<0.05) decrease in IL-17 and IFN-gamma intracellular expression compared with PHA alone. Also, the percentage of T CD4⁺IL-17⁺, T CD4⁺IFNgamma⁺ and T CD4⁺IL-4⁺ cells were significantly reduced (p<0.05) by sitagliptin. Our data demonstrated an immunosuppressive effect of sitagliptin on Th1, Th17 and Th2 lymphocytes differentiation that leads to the generation of regulatory TGF-beta1 secreting cells with low CD26 gene expression that may influence the state of pancreatic beta-cells and controlling DM1 patients.