scholarly journals Identification of Germline Monoallelic Mutations in IKZF2 in Patients with Immune Dysregulation

2021 ◽  
Author(s):  
Tala Shahin ◽  
Daniel Mayr ◽  
Mohamed R Shoeb ◽  
Hye Sun Kuehn ◽  
Birgit Hoeger ◽  
...  
Keyword(s):  
T Cell ◽  
Lupus Erythematosus ◽  
Cell Receptor ◽  
Germline Mutations ◽  
Receptor Activation ◽  
Cell Physiology ◽  
T Regulatory Cell ◽  
Nurd Complex ◽  
Follicular Helper ◽  
Core Components

Helios, encoded by IKZF2, is a member of the Ikaros family of transcription factors with pivotal roles in T-follicular helper, NK- and T-regulatory cell physiology. Somatic IKZF2 mutations are frequently found in lymphoid malignancies. Although germline mutations in IKZF1 and IKZF3, encoding Ikaros and Aiolos, have recently been identified in patients with phenotypically similar immunodeficiency syndromes, the effect of germline mutations in IKZF2 on human hematopoiesis and immunity remains enigmatic. We identified germline IKZF2 mutations (one nonsense (p.R291X)- and 4 distinct missense variants) in six patients with systemic lupus erythematosus, immune thrombocytopenia or EBV-associated hemophagocytic lymphohistiocytosis. Patients exhibited hypogammaglobulinemia, decreased number of T-follicular helper and NK-cells. Single-cell RNA sequencing of PBMCs from the patient carrying the R291X variant revealed upregulation of pro-inflammatory genes associated with T-cell receptor activation and T-cell exhaustion. Functional assays revealed the inability of HeliosR291X to homodimerize and bind target DNA as dimers. Moreover, proteomic analysis by proximity-dependent Biotin Identification revealed aberrant interaction of 3/5 Helios mutants with core components of the NuRD complex conveying HELIOS-mediated epigenetic and transcriptional dysregulation.

scholarly journals Large-scale proteomic analysis of tyrosine-phosphorylation induced by T-cell receptor or B-cell receptor activation reveals new signaling pathways

PROTEOMICS ◽  
2009 ◽  
Vol 9 (13) ◽  
pp. 3549-3563 ◽  
Author(s):  
Masaki Matsumoto ◽  
Koji Oyamada ◽  
Hidehisa Takahashi ◽  
Takamichi Sato ◽  
Shigetsugu Hatakeyama ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Signaling Pathways ◽  
Tyrosine Phosphorylation ◽  
T Cell Receptor ◽  
Proteomic Analysis ◽  
Large Scale ◽  
Cell Receptor ◽  
Receptor Activation ◽  
B Cell Receptor

T-cell receptor and HLA class II RFLPs in systemic lupus erythematosus

1988 ◽  
Vol 27 (5) ◽  
pp. 392-395 ◽  
Author(s):  
H. Dunckley ◽  
P. A. Gatenby ◽  
S. W. Serjeantson
Keyword(s):  
Systemic Lupus Erythematosus ◽  
T Cell ◽  
T Cell Receptor ◽  
Lupus Erythematosus ◽  
Cell Receptor ◽  
Class Ii ◽  
Hla Class Ii ◽  
Systemic Lupus

scholarly journals Germinal center formation, immunoglobulin class switching, and autoantibody production driven by "non alpha/beta" T cells.

1996 ◽  
Vol 183 (5) ◽  
pp. 2271-2282 ◽  
Author(s):  
L Wen ◽  
W Pao ◽  
F S Wong ◽  
Q Peng ◽  
J Craft ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lupus Erythematosus ◽  
Cell Receptor ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Autoantibody Production ◽  
Ige Synthesis ◽  
Alpha Beta ◽  
T Cell Help

The production of class-switched antibodies, particularly immunoglobulin (Ig) G1 and IgE, occurs efficiently in T cell receptor (TCR) alpha-/- mice that are congenitally devoid of alpha/beta T cells. This finding runs counter to a wealth of data indicating that IgG1 and IgE synthesis are largely dependent on the collaboration between B and alpha/beta T cells. Furthermore, many of the antibodies synthesized in TCR alpha-/- mice are reactive to a similar spectrum of self-antigens as that targeted by autoantibodies characterizing human systemic lupus erythematosus (SLE). SLE, too, is most commonly regarded as an alpha/beta T cell-mediated condition. To distinguish whether the development of autoantibodies in TCR alpha-/- mice is due to an intrinsic de-regulation of B cells, or to a heretofore poorly characterized collaboration between B and "non-alpha/beta T" cells, the phenotype has been reconstituted by transfer of various populations of B and non-alpha/beta T cells including cloned gamma/delta T cells derived from TCR alpha-/- mice, to severe combined immunodeficient (SCID) mice. The results establish that the reproducible production of IgG1 (including autoantibodies) is a product of non-alpha/beta T cell help that can be provided by gamma/delta T cells. This type of B-T collaboration sustains the production of germinal centers, lymphoid follicles that ordinarily are anatomical signatures of alpha/beta T-B cell collaboration. Thus, non-alpha/beta T cell help may drive Ig synthesis and autoreactivity under various circumstances, especially in cases of alpha/beta T cell immunodeficiency.

scholarly journals 9-cis retinoic acid inhibition of activation-induced apoptosis is mediated via regulation of fas ligand and requires retinoic acid receptor and retinoid X receptor activation.

1995 ◽  
Vol 15 (10) ◽  
pp. 5576-5585 ◽  
Author(s):  
R P Bissonnette ◽  
T Brunner ◽  
S B Lazarchik ◽  
N J Yoo ◽  
M F Boehm ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
T Cell ◽  
T Cell Receptor ◽  
Target Genes ◽  
Fas Ligand ◽  
Apoptotic Cell ◽  
Cell Receptor ◽  
Receptor Activation ◽  
Retinoid Receptor ◽  
Induced Apoptosis

T-cell hybridomas, thymocytes, and T cells can be induced to undergo apoptotic cell death by activation through the T-cell receptor. This process requires macromolecular synthesis and thus gene expression, and it has been shown to be influenced by factors regulating transcription. Recently, activation, T-cell hybridomas rapidly express the Fas/CD95 receptor and its ligand, Fas ligand (FasL), which interact to transduce the death signal in the activated cell. Retinoids, the active metabolites of vitamin A, modulate expression of specific target genes by binding to two classes of intracellular receptors, retinoic acid receptors (RARs) and retinoid X receptors (RXRs). They are potent modulators of apoptosis in a number of experimental models, and they have been shown to inhibit activation-induced apoptosis in T-cell hybridomas and thymocytes. Particularly effective is the prototypic pan-agonist 9-cis retinoic acid (9-cis RA), which has high affinity for both RARs and RXRs. We report here that 9-cis RA inhibits T-cell receptor-mediated apoptosis in T-cell hybridomas by blocking the expression of Fas ligand following activation. This inhibition appears to be at the level of FasL mRNA, with the subsequent failure to express cell surface FasL. RAR-selective (TTNPB) or RXR-selective (LG100268) ligands alone were considerably less potent than RAR-RXR pan-agonists. However, the addition of both RAR- and RXR-selective ligands was as effective as the addition of 9-cis RA alone. The demonstrates that the inhibitory effect requires the ligand-mediated activation of both retinoid receptor signaling pathways.

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