Development of type 1 diabetes mellitus in nonobese diabetic mice follows changes in thymocyte and peripheral T lymphocyte transcriptional activity

Comparative Analysis of the Transcriptome of Latent Autoimmune Diabetes in Adult (LADA) Patients from Eastern China

Latent autoimmune diabetes in adults (LADA) is characterized as a slow-progressing form of autoimmune diabetes. LADA resembles some phenotypes of type 1 diabetes (T1D) and type 2 diabetes (T2D), frequently leading to misdiagnosis and inappropriate therapeutic strategies. Understanding its transcriptome profiles aids in revealing the detailed molecular mechanisms of LADA and its therapy. In the present study, we performed RNA-seq analysis of LADA patients from Eastern China and showed that LADA exhibited 277 differentially expressed genes (DEGs) with 199 upregulated and 78 downregulated. Gene ontology and KEGG pathway enrichment analysis revealed that these DEGs were mainly related to immune function and cell death and growth. Furthermore, a comparison of DEGs in LADA with those in T1D and T2D identified from the online databases showed that there are very few overlapped genes between LADA and T1D or T2D, confirming LADA to be a distinct type of diabetes from T1D or T2D. In summary, our comprehensive analysis may aid in the understanding and treatment of LADA patients in Eastern China.

Abnormal T-Cell Development in the Thymus of Non-obese Diabetic Mice: Possible Relationship With the Pathogenesis of Type 1 Autoimmune Diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by the destruction of insulin-producing cells in the pancreas, by direct interactions with autoreactive pancreas infiltrating T lymphocytes (PILs). One of the most important animal models for this disease is the non-obese diabetic (NOD) mouse. Alterations in the NOD mouse thymus during the pathogenesis of the disease have been reported. From the initial migratory disturbances to the accumulation of mature thymocytes, including regulatory Foxp3+ T cells, important mechanisms seem to regulate the repertoire of T cells that leave the thymus to settle in peripheral lymphoid organs. A significant modulation of the expression of extracellular matrix and soluble chemoattractant molecules, in addition to integrins and chemokine receptors, may contribute to the progressive accumulation of mature thymocytes and consequent formation of giant perivascular spaces (PVS) that are observed in the NOD mouse thymus. Comparative large-scale transcriptional expression and network analyses involving mRNAs and miRNAs of thymocytes, peripheral T CD3+ cells and PILs provided evidence that in PILs chemokine receptors and mRNAs are post-transcriptionally regulated by miR-202-3p resulting in decreased activity of these molecules during the onset of T1D in NOD mice. In this review, we discuss the abnormal T-cell development in NOD mice in the context of intrathymic expression of different migration-related molecules, peptides belonging to the family of insulin and insulin-like growth factors as well as the participation of miRNAs as post-transcriptional regulators and their possible influence on the onset of aggressive autoimmunity during the pathogenesis of T1D.

Class I-Restricted T Cell-Associated Molecule Is a Marker for IFN-γ-Producing iNKT Cells in Healthy Subjects and Patients with Type 1 Diabetes

Class I-restricted T cell-associated molecule (CRTAM) is an activation marker expressed on the cell surface of activated invariant natural killer T (iNKT) cells, CD8⁺ T cells, and a small subset of CD4⁺ T cells. CRTAM has also been associated with a proinflammatory profile in murine CD4⁺ T cells. However, CRTAM has not been thoroughly explored in human cells. This work focused on evaluating CRTAM expression in human iNKT lymphocytes after activation with α-galactosylceramide, its widely used specific glycolipid antigen. We also analyzed the involvement of costimulatory molecules in CRTAM expression and whether CRTAM expression is associated with a specific effector cytokine profile. We found that the signal produced by invariant T cell receptor (iTCR) engagement with α-galactosylceramide is sufficient to trigger CRTAM expression on human iNKT cells after 18 h of stimulation. Moreover, we observed a clear association between CRTAM expression and IFN-γ production in iNKT cells from healthy subjects and patients with type 1 diabetes. However, blocking the engagement of costimulatory molecules, such as CD40, CD80, and CD86, did not modify CRTAM expression. These results indicate that CRTAM may also play a role in triggering the production of IFN-γ in human iNKT cells and that CRTAM could be used as a marker to identify these inflammatory cells.

Reduced iNKT cells numbers in type 1 diabetes patients and their first-degree relatives

Type 1 diabetes (T1D) is an autoimmune disease that is characterized by the specific destruction of insulin-producing pancreatic β cells. Invariant natural killer T (iNKT) cells have been associated with development of T1D. Class I MHC-restricted T cell-associated molecule (CRTAM) is expressed on activated iNKT, CD8(+), and CD4(+) T cells, and it is associated with the pro-inflammatory profiles of these cells. Crtam gene expression in CD3(+) lymphocytes from non-obese diabetic (NOD) mice is associated with T1D onset. However, expression of CRTAM on T cells from patients with T1D has not yet been evaluated. We compared iNKT cell (CD3(+)Vα24(+)Vβ11(+)) numbers and CRTAM expression in a Mexican population with recent-onset T1D and their first-degree relatives with control families. Remarkably, we found lower iNKT cell numbers in T1D families, and we identified two iNKT cell populations in some of the families. One iNKT cell population expressed high iTCR levels (iNKT(hi)), whereas another expressed low levels (iNKT(lo)) and also expressed CRTAM. These findings support a probable genetic determinant of iNKT cell numbers and a possible role for these cells in T1D development. This study also suggests that CRTAM identifies recently activated iNKT lymphocytes.

Comprehensive Survey of miRNA-mRNA Interactions Reveals That Ccr7 and Cd247 (CD3 zeta) are Posttranscriptionally Controlled in Pancreas Infiltrating T Lymphocytes of Non-Obese Diabetic (NOD) Mice

In autoimmune type 1 diabetes mellitus (T1D), auto-reactive clones of CD4+ and CD8+ T lymphocytes in the periphery evolve into pancreas-infiltrating T lymphocytes (PILs), which destroy insulin-producing beta-cells through inflammatory insulitis. Previously, we demonstrated that, during the development of T1D in non-obese diabetic (NOD) mice, a set of immune/inflammatory reactivity genes were differentially expressed in T lymphocytes. However, the posttranscriptional control involving miRNA interactions that occur during the evolution of thymocytes into PILs remains unknown. In this study, we postulated that miRNAs are differentially expressed during this period and that these miRNAs can interact with mRNAs involved in auto-reactivity during the progression of insulitis. To test this hypothesis, we used NOD mice to perform, for the first time, a comprehensive survey of miRNA and mRNA expression as thymocytes mature into peripheral CD3+ T lymphocytes and, subsequently, into PILs. Reconstruction of miRNA-mRNA interaction networks for target prediction revealed the participation of a large set of miRNAs that regulate mRNA targets related to apoptosis, cell adhesion, cellular regulation, cellular component organization, cellular processes, development and the immune system, among others. The interactions between miR-202-3p and the Ccr7 chemokine receptor mRNA or Cd247 (Cd3 zeta chain) mRNA found in PILs are highlighted because these interactions can contribute to a better understanding of how the lack of immune homeostasis and the emergence of autoimmunity (e.g., T1D) can be associated with the decreased activity of Ccr7 or Cd247, as previously observed in NOD mice. We demonstrate that these mRNAs are controlled at the posttranscriptional level in PILs.

Integrative analysis of the transcriptome profiles observed in type 1, type 2 and gestational diabetes mellitus reveals the role of inflammation

BACKGROUND

Type 1 diabetes (T1D) is an autoimmune disease, while type 2 (T2D) and gestational diabetes (GDM) are considered metabolic disturbances. In a previous study evaluating the transcript profiling of peripheral mononuclear blood cells obtained from T1D, T2D and GDM patients we showed that the gene profile of T1D patients was closer to GDM than to T2D. To understand the influence of demographical, clinical, laboratory, pathogenetic and treatment features on the diabetes transcript profiling, we performed an analysis integrating these features with the gene expression profiles of the annotated genes included in databases containing information regarding GWAS and immune cell expression signatures.

METHODS

Samples from 56 (19 T1D, 20 T2D, and 17 GDM) patients were hybridized to whole genome one-color Agilent 4x44k microarrays. Non-informative genes were filtered by partitioning, and differentially expressed genes were obtained by rank product analysis. Functional analyses were carried out using the DAVID database, and module maps were constructed using the Genomica tool.

RESULTS

The functional analyses were able to discriminate between T1D and GDM patients based on genes involved in inflammation. Module maps of differentially expressed genes revealed that modulated genes: i) exhibited transcription profiles typical of macrophage and dendritic cells; ii) had been previously associated with diabetic complications by association and by meta-analysis studies, and iii) were influenced by disease duration, obesity, number of gestations, glucose serum levels and the use of medications, such as metformin.

CONCLUSION

This is the first module map study to show the influence of epidemiological, clinical, laboratory, immunopathogenic and treatment features on the transcription profiles of T1D, T2D and GDM patients.

High expression of OX40 (CD134) and 4-1BB (CD137) molecules on CD4(+)CD25(high) cells in children with type 1 diabetes

PURPOSE

Despite the rapidly rising incidence of diabetes in children, with the highest rise in children<5 years of age, data on mechanisms that trigger severe beta-cells damage are limited. The aim of the study was to assess the frequency of OX40 (CD134) or 4-1BB (CD137) positive cells in the peripheral blood of children with newly diagnosed type 1 diabetes (T1D) in comparison to healthy controls.

MATERIAL/METHODS

The study included 33 children (mean age 7.3 ± 5.4 years) with newly diagnosed T1D and 39 age-matched healthy controls. Separate analysis was performed in children<5 years. Flow cytometric analysis was performed using the following markers: CD4, CD25, CD137, and CD134. Fasting C-peptide level was assessed as well.

RESULTS

The frequency of CD4(+)CD25(high)OX40(+) was higher in T1D children than in controls (median value 3.58% vs. 1.1%, respectively; p=0.003). Moreover, T1D children had higher frequency of CD4(+)CD25(high)4-1BB(+) cells than healthy subjects (median value 5.76% vs. 3.74%, respectively; p=0.037). A significant correlation was noted between the age of diabetic children and the C-peptide level (r=0.54, 95% CI [0.19-0.77], p=0.004). In comparison with age-matched controls, children<5 years had higher frequency of CD4(+)CD25(high)OX40(+) (p=0.004) and CD4(+)CD25(high)4-1BB(+) cells (p=0.079).

CONCLUSIONS

Our study showed higher frequency of both OX40 and 4-1BB positive cells in T1D children in comparison to controls. It seems that observed differences might be more pronounced in children<5 years of age than in older subjects. Further clinical studies are needed to determine the age-related differences in the immune system, in the pathogenesis of T1D.