PRMT5 Promotes Progression of Chronic Lymphocytic Leukemia [scRNA-Seq]

Purpose: Richter’s Transformation (RT) is a poorly understood and often fatal progression of chronic lymphocytic leukemia (CLL) manifesting histologically as diffuse large B-cell lymphoma. PRMT5 is implicated in lymphomagenesis, but its role in CLL or RT progression is unknown. We demonstrate herein that tumors uniformly overexpress PRMT5 in patients with progression to RT. Furthermore, mice with B-specific overexpression of hPRMT5 developed a B-lymphoid expansion with increased risk of death, and Eµ-PRMT5/TCL1 double transgenic mice uniformly developed a highly aggressive disease that histologically resembles RT; where large-scale transcriptional profiling identified unique oncogenic pathways that mediate PRMT5-driven disease progression. Taken together, the discovery that PRMT5 drives oncogenic pathways promoting RT provides a compelling rationale for clinical investigation of PRMT5 inhibitors such as PRT382 in aggressive CLL/RT cases - RNA-sequencing from B cells isolated from the spleen of Eµ-PRMT5, Eµ-PRMT5/TCL1, and Eµ-TCL1 mice at ERC. - RNA-sequencing and ATAC-sequencing from B cells isolated from the spleen of Eµ-PRMT5/TCL1 and Eµ-TCL1 mice at 3 and 6 months of age. - Single cell RNA-sequencing in Eµ-PRMT5, Eµ-PRMT5/TCL1, and Eµ-TCL1 mice at ERC.

研究目的：Richter转化（Richter’s Transformation, RT）是一类预后凶险且常致命的慢性淋巴细胞白血病（chronic lymphocytic leukemia, CLL）进展亚型，其组织学表现为弥漫性大B细胞淋巴瘤，目前对其发病机制尚不明晰。蛋白精氨酸甲基转移酶5（Protein Arginine Methyltransferase 5, PRMT5）已被证实参与淋巴瘤发生过程，但其在CLL或RT进展中的具体作用尚未明确。本研究证实，进展为RT的患者肿瘤组织中PRMT5呈普遍性高表达。进一步实验显示，B细胞特异性过表达人PRMT5（hPRMT5）的小鼠可出现B淋巴系细胞扩增，且死亡风险升高；而Eµ-PRMT5/TCL1双转基因小鼠均会发生高度侵袭性疾病，其组织学特征与RT高度相似。通过大规模转录组分析，本研究鉴定出介导PRMT5驱动疾病进展的独特致癌通路。综上，PRMT5可激活促进RT发生的致癌通路这一发现，为侵袭性CLL/RT患者使用PRT382等PRMT5抑制剂开展临床研究提供了极具说服力的理论依据。
- 从ERC阶段的Eµ-PRMT5、Eµ-PRMT5/TCL1及Eµ-TCL1小鼠脾脏中分离的B细胞进行RNA测序（RNA-sequencing, RNA-seq）
- 对3月龄及6月龄的Eµ-PRMT5/TCL1与Eµ-TCL1小鼠脾脏中分离的B细胞进行RNA测序及转座酶可及性测序（ATAC-sequencing, ATAC-seq）
- 对ERC阶段的Eµ-PRMT5、Eµ-PRMT5/TCL1及Eµ-TCL1小鼠进行单细胞RNA测序（Single cell RNA-sequencing, scRNA-seq）