Abnormal expression and mutation of the RBPJ gene may be involved in CD59‑ clonal proliferation in paroxysmal nocturnal hemoglobinuria

Abstract

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal proliferative disease of hematopoietic stem cells. Various gene mutations, including the phosphatidylinositol glycan anchor biosynthesis class A (PIG-A) gene, may contribute to the proliferation of PNH clones. In order to explore the mechanism of PNH clone proliferation, a study was performed on 13 patients with PNH who underwent whole exome sequencing. The frequency of mutations in these patients was explored, and an additional 30 patients with PNH were selected for analysis of cluster of differentiation 59-negative (CD59 − ) cells. The mRNA expression of 13 genes, which were selected based on their high frequency in patients with PNH and the fact that they met four screening conditions, was determined in these CD59 − cells. Cell proliferation, apoptosis and cell cycle were evaluated upon knocking down the recombinant signal binding protein of immunoglobulin κJ region (RBPJ) gene in 5 patients in vitro . The detection rate of PIG-A gene mutation was 61.54% (8/13), and additional mutations in somatic genes were detected, including RBPJ, zinc finger protein 717, polycomb repressive complex 2 subunit and tet methylcytosine dioxygenase. Upon screening according to the mutation frequency and expression level, the present study focused on the RBPJ gene. The expression level of RBPJ in CD59 − cells was apparently higher than that in CD59 + cells and normal controls which was significantly correlated with clinical data. Furthermore, the expression of RBPJ in PNH primary cells could be effectively inhibited by small interfering RNA-RBPJ. Once the expression of RBPJ decreased remarkably, the apoptotic rate increased gradually, while cell proliferation activity decreased with transfection time and cells were blocked in G0/G1 phase. In conclusion, mutations and abnormal expression of the RBPJ gene may participate in the abnormal proliferation of PNH clones.

A Pig-a conditional knock-out mice model mediated by Vav-iCre: stable GPI-deficient and mild hemolysis

“…The differences between the patient and PNH mice models also reconfirmed that the proliferation advantage of PNH clones requires the participation of other unknown factors besides the PIG-A mutation. Some scholars have studied the secondary mutation genes of PNH patients and screened out some high-frequency mutations [ 29 – 31 ], while the mechanism research is still very difficult. The CKO heterozygous mice might be the suitable model for the further study.…”

Long Non-Coding RNA FAM157C Contributed to Clonal Proliferation in Paroxysmal Nocturnal Hemoglobinuria

“…The theory of secondary genetic mutations has been reported since the 1970s 21 . Additional mutant genes such as HMGA2 29 30 , WT1 31 , TET2 32 and RBPJ 33 have been reported in PNH patients. Most cases of PNH can carry additional mutations and these mutations are secondary strikes.…”

The expression and clinical significance of CD59 and FLAER in Chinese adult AML patients

“… 22 , 23 , 24 Our previous research demonstrated that abnormal expression and mutation of RBPJ gene might contribute to CD59 − clonal proliferation. 25 In addition, a study from Byrne et al indicated that PIG‐A assay is a sensitive method for serial assessment of genomic instability in mouse models of MDS. 26 Therefore, whether PIG‐A gene mutation has resulted in the lack of CD59 deficiency in AML remains unclear.…”