BATF高表达对再生障碍性贫血T细胞分化及功能的影响

In the previous study, we found over activated Th1 and Tc1, helped by abnomal Th17, coupled with Treg which had insufficient function existing simultaneously in aplastic anemia (AA). BATF is a transcription factor that regulates the differentiation and function of T lymphocytes, and plays an important role in the differentiation of HSCs to lymphoid lineage and the accumulation of DNA damage of HSCs. Recently I found that mRNA expression of BATF in patients with AA was significantly increased, and BATF expression in both CD3+CD8-T and CD3+CD8+T lymphocytes from AA patients were increased. We intend to investigate by clinical and animal experiments, using flow cytometry and RT-PCR to verify the scientific hypotheses: In AA patients, BATF over expression causes HSC with lymphoid differentiation bias, T lymphocyte subsets imbalance and BATF expression relatively deficiency may lead to the accumulation of the malignant clone of AA. This study may reveal the relationship between BATF and AA, and provide a new target for the treatment of AA in the future.

课题组前期研究发现Th1、Tc1功能亢进，Treg调节不足，Th17推波助澜是典型再障的免疫状态。BATF是调节T淋巴细胞分化和功能的重要转录因子，对HSC向淋巴系分化及DNA损伤积累意义重大。申请人近期研究发现BATF mRNA在AA患者PMNC表达明显增高，且CD3+CD8-T及CD3+CD8+T细胞BATF表达均增多。我们拟通过临床及动物实验，利用流式细胞术及RT-PCR方法分析BATF高表达对AA患者HSC分化、T淋巴细胞向各亚群分化的影响，及其对各亚群T淋巴细胞功能的影响，并将BATF表达量与临床指标进行相关性分析，验证科学假说：BATF表达增高造成AA HSC具淋系分化倾向、T淋巴细胞向Th1、Tc1分化偏移，Treg生成减少，Th17增多，AA发病；AA恶性克隆转变可能与BATF表达不足有关。本研究从不同层面揭示了BATF与AA的发病的关系，为AA今后治疗提供可能的新靶点。

再生障碍性贫血（AA）是血液系统重症，至今发病机制尚不十分明确，虽然强效免疫抑制治疗及造血干细胞移植治疗已明显提高了再障治疗的有效率，仍有30%AA患者治疗无效甚至死亡。课题组前期研究发现Th1、Tc1功能亢进，Treg调节不足，Th17推波助澜是典型AA的免疫状态，影响淋巴细胞亚群分化的重要转录因子BATF在AA患者中表达升高。本课题在前期研究的基础之上，1）发现BATF在初治AA患者外周血淋巴细胞中表达明显高于治疗恢复组及对照组，并与AA患者疾病的严重程度密切相关。BATF表达升高与IFN-γ+CD8+T淋巴细胞数量增多功能亢进及Th1/Th2分化偏移密切相关。2）利用电转技术将gRNA/Cas9酶高效率敲入人原代Naïve CD4+T细胞实现基因组水平BATF基因敲除，诱导敲除及未敲除的Naïve CD4+T细胞向Th1,Th2,Th17细胞亚群分化，结果显示：BATF基因敲除影响Naïve CD4+T细胞向Th1及Th17细胞分化，对其向Th2分化影响不显著。在体外细胞水平证实BATF是Naïve CD4+T向下游Th1,Th2,Th17各亚群分化的关键调控因子，起到调节Th细胞各亚群平衡的作用。3）动物模型证实，SAA小鼠T淋巴细胞BATF表达升高，回输BATF基因敲除的T淋巴细胞，小鼠外周血红细胞、白细胞、血小板有明显恢复趋势，骨髓造血也较AA未治疗组明显好转，因此调节T淋巴细胞BATF基因表达有望作为治疗再生障碍性贫血的新方向。