scholarly journals γ-Aminobutyric Acid Inhibits T Cell Autoimmunity and the Development of Inflammatory Responses in a Mouse Type 1 Diabetes Model

2004 ◽  
Vol 173 (8) ◽  
pp. 5298-5304 ◽  
Author(s):  
Jide Tian ◽  
Yuxin Lu ◽  
Hanwei Zhang ◽  
Cindy H. Chau ◽  
Hoa N. Dang ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Inflammatory Responses ◽  
Aminobutyric Acid ◽  
Diabetes Model

scholarly journals A Single L/D-Substitution at Q4 of the mInsA2-10 Epitope Prevents Type 1 Diabetes in Humanized NOD Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Mengjun Zhang ◽  
Yuanqiang Wang ◽  
Xiangqian Li ◽  
Gang Meng ◽  
Xiaoling Chen ◽  
...  
Keyword(s):  
Amino Acids ◽  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Inflammatory Responses ◽  
Nod Mice ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Altered Peptide Ligands

Autoreactive CD8+ T cells play an indispensable key role in the destruction of pancreatic islet β-cells and the initiation of type 1 diabetes (T1D). Insulin is an essential β-cell autoantigen in T1D. An HLA-A*0201-restricted epitope of insulin A chain (mInsA2-10) is an immunodominant ligand for autoreactive CD8+ T cells in NOD.β2mnull.HHD mice. Altered peptide ligands (APLs) carrying amino acid substitutions at T cell receptor (TCR) contact positions within an epitope are potential to modulate autoimmune responses via triggering altered TCR signaling. Here, we used a molecular simulation strategy to guide the generation of APL candidates by substitution of L-amino acids with D-amino acids at potential TCR contact residues (positions 4 and 6) of mInsA2-10, named mInsA2-10DQ4 and mInsA2-10DC6, respectively. We found that administration of mInsA2-10DQ4, but not DC6, significantly suppressed the development of T1D in NOD.β2mnull.HHD mice. Mechanistically, treatment with mInsA2-10DQ4 not only notably eliminated mInsA2-10 autoreactive CD8+ T cell responses but also prevented the infiltration of CD4+ T and CD8+ T cells, as well as the inflammatory responses in the pancreas of NOD.β2mnull.HHD mice. This study provides a new strategy for the development of APL vaccines for T1D prevention.

scholarly journals CTLA-4 (+49A/G) Polymorphism in Type 1 Diabetes Children of Sudanese Population

2021 ◽  
Vol 08 (01) ◽  
pp. 011-018
Author(s):  
Khalid E. Khalid Kheiralla
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Ethylenediaminetetraacetic Acid ◽  
Negative Regulator ◽  
Cytotoxic Lymphocyte ◽  
Pediatric Clinic ◽  
Homozygous Genotype ◽  
Organ Specific ◽  
Α Helix

Abstract Background Type 1 diabetes mellitus (T1DM) is an organ-specific T cell-mediated autoimmune disease, characterized by destruction of pancreatic islets. Cytotoxic lymphocyte antigen-4 (CTLA-4) is a negative regulator of T cell proliferation, thus conferring susceptibility to autoimmunity. Aims This study aimed to investigate the association of CTLA-4 +49A/G (rs231775) polymorphism with a risk of T1DM in Sudanese children. Methods This a case–control study included 100 children with T1DM, referred to the pediatric clinic at referral pediatric teaching hospital in Gezira State-Sudan. Hundred unrelated healthy controls were recruited from departments in the same hospital. Genomic deoxyribonucleic acid (DNA) was extracted from Ethylenediaminetetraacetic Acid (EDTA)-preserved blood using QIAamp DNA Blood Mini Kit (QIAamp Blood) (QIAGEN; Valencia, CA). The polymerase chain reaction PCR restriction fragment length polymorphism (PCR-RFLP) and sequencing were applied for the CTLA-4 (+49A/G) genotyping. The changes accompanied the polymorphism were evaluated using relevant bioinformatics tools. Results The genotype and allele frequencies of the CTLA-4 (+49A/G) polymorphism were significantly different between the patients and controls (p = 0.00013 and 0.0002, respectively). In particular, the frequency of the G allele, GG homozygous genotype, and AG heterozygous genotype were significantly increased in patients than in controls ([28% versus 7%, odds ratio (OR) = 5.16, 95% confidence interval [CI] = 2.77–9.65, p = 0.00] [12% versus 2%, OR = 6.68, CI = 1.46–30.69, p = 0.01] [32% versus 10%, OR = 4.24, CI = 1.95–9.21, p = 0.00], respectively). The presence of the G allele (homozygous) showed an influence on the signal peptide polarity, hydrophobicity, and α-helix propensity of the CTLA-protein. Conclusion The results further support the association of CTLA-4 (+49A/G) polymorphism and the risk of T1DM in our study population.

scholarly journals Effect of Coxsackievirus B4 Infection on the Thymus: Elucidating Its Role in the Pathogenesis of Type 1 Diabetes

2021 ◽  
Vol 9 (6) ◽  
pp. 1177
Author(s):  
Abdulaziz Alhazmi ◽  
Magloire Pandoua Nekoua ◽  
Hélène Michaux ◽  
Famara Sane ◽  
Aymen Halouani ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Viral Infections ◽  
Lymphoid Organ ◽  
Thymic Epithelial Cells ◽  
Central Tolerance ◽  
Coxsackievirus B4

The thymus gland is a primary lymphoid organ for T-cell development. Various viral infections can result in disturbance of thymic functions. Medullary thymic epithelial cells (mTECs) are important for the negative selection of self-reactive T-cells to ensure central tolerance. Insulin-like growth factor 2 (IGF2) is the dominant self-peptide of the insulin family expressed in mTECs and plays a crucial role in the intra-thymic programing of central tolerance to insulin-secreting islet β-cells. Coxsackievirus B4 (CVB4) can infect and persist in the thymus of humans and mice, thus hampering the T-cell maturation and differentiation process. The modulation of IGF2 expression and protein synthesis during a CVB4 infection has been observed in vitro and in vivo in mouse models. The effect of CVB4 infections on human and mouse fetal thymus has been studied in vitro. Moreover, following the inoculation of CVB4 in pregnant mice, the thymic function in the fetus and offspring was disturbed. A defect in the intra-thymic expression of self-peptides by mTECs may be triggered by CVB4. The effects of viral infections, especially CVB4 infection, on thymic cells and functions and their possible role in the pathogenesis of type 1 diabetes (T1D) are presented.

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