RNA Sequencing Analysis of T Cell Receptor Alpha and Beta Chain in Thymic WT versus CIC-deficient CD4+ SP Non-Treg and Treg Cells.

Purpose : The goal of this study is to compare the repertoire of T cell receptor (TCR) alpha and beta chain between WT and CIC-deficient thymic CD4+ single positive (SP) T cells, in both non-Treg and Treg populations, to confirm the effect of CIC deficiency on T cell development in the aspect of TCR repertoire. Methods : Treg (CD4+CD8-CD25+GFP+) and non-Treg (CD4+CD8-GFP-) cells from Foxp3-GFP;Cicf/f and Foxp3-GFP;Cicf/f;Vav1-Cre mice were sorted by MoFlo-XDP (Beckman Coulter). Total RNA was extracted using RiboEX (GeneAll) according to the manufacturer's instructions. RNA was then amplified using a commercially available multiplex primer mix covering the TCR alpha and beta chains in two separate PCR reactions. Reverse transcription and subsequent PCR amplification (RT-PCR1) were performed using the Qiagen OneStep RT PCR mix (Qiagen). The cDNA was selected and unused primers were removed by SPRIselect bead selection (Beckman Coulter) followed by a second round of amplification performed with a pair of primers specific for communal sites engineered onto the 5ʹ end of the C- and V- primers used during RT-PCR1. After library preparation, paired-end sequencing was performed using the Illumina Miseq v3 600-cycle Reagent Kit (Illumina). Results : We observed increased frequency of TCRs with long CDR3 length in CIC-deficient non-Treg and Treg cells. We also found significant alterations in the TCR repertoire of TCR beta chain in CIC-deficient Treg cells compared to WT cells, including altered frequency of V and J chain usage. Conclusions : Our study represents the first comparative analysis of TCR repertoire of thymic CD4 SP cells from WT and hematopoietic lineage cell-specific Cic deficient mice. We concluded that CIC deficiency leads to alterations in TCR repertoire of thymic Treg cells. TCR alpha and beta chain of Treg (CD4+CD8-CD25+GFP+) and non-Treg (CD4+CD8-GFP-) cells from Foxp3-GFP;Cicf/f and Foxp3-GFP;Cicf/f;Vav1-Cre mice were sequenced for TCR repertoire analysis.