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Paroxysmal nocturnal hemoglobinuria (PNH) is a disease involving hematopoietic stem cell membrane defects caused by acquired phosphatidylinositol glycan anchor biosynthesis class A (PIGA) mutations. In this study, 97 target genes were selected as a target gene panel and screened in 23 PNH patients via the sequencing of specific DNA target regions. Through functional analysis, we identified that suppressor‐of‐Zeste 12 (SUZ12) may be involved in the proliferation of PNH clones. mRNA and protein expression levels of SUZ12 and the trimethylation level of histone H3 at lysine 27 (H3K27) in CD59– peripheral blood leukocytes from PNH patients were higher than those in CD59+ cells from PNH patients and peripheral blood leukocytes from healthy controls. In addition, the relative expression of SUZ12 in PNH patients was positively correlated with Ret% and the proportion of PNH clones. When we knocked down SUZ12 expression in a PIGA knockdown THP‐1 cell line (THP‐1 KD cells), the trimethylation of histone H3K27(H3K27me3) and cell proliferation decreased, apoptosis increased, and cell cycle arrest occurred in G0/G1 phase. In conclusion, SUZ12 participates in the proliferation of PNH clones by regulating histone H3K27me3 levels. Our results may provide new therapeutic targets and possibilities for PNH patients. [ABSTRACT FROM AUTHOR]

Background: Thrombosis is a most common and lethal complication of paroxysmal nocturnal hemoglobinuria (PNH), which is a complex progression and its mechanism remains unclear. We tried to explore the possible genetic background of thrombosis in PNH patients and provide potential gene mutations associated with thrombosis in PNH patients. Methods: The CD59− cells of 7 PNH and 6 PNH‐ aplastic anemia (AA) patients were sorted by flow cytometry and sequenced by whole‐exome sequencing (WES). The sequencing results and target mutation genes were analyzed and screened, respectively, and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathway enrichment analysis was carried out. Finally, the expression of target genes was detected in 22 PNH (including seven cases with thrombus) and 20 normal controls, and the correlation between the expression of mRNA and the clinical thrombus‐related indexes was analyzed. Results: The mutation genes screened from 4 PNH with thrombus were BMPR2, F8, ITGA2B, THBD, and THBS1. The pathways enriched by these genes included Notch, Wnt, and arachidonic acid metabolism signaling pathways, which may be related to the pathogenesis of thrombosis in PNH. The BMPR2, THBD, and THBS1 gene expression was significantly different between PNH with and without thrombus group, and the THBS1 gene expression was positively correlated with D‐Dimer and su‐PAR levels. Conclusions: Genetic defects have a non‐negligible effect on the incidence of thrombosis, and therefore, gene mutations maybe a genetic risk factor in PNH, which increase the incidence of thrombosis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Proteinase 3 (PR3) is released from neutrophils and regulates platelet activity, which is associated with cluster of differentiation (CD)177 antigen (NB1), a glycosylphosphatidylinositol‑linked protein. In the present study, the effect of PR3 on thrombosis in paroxysmal nocturnal hemoglobinuria (PNH) and PNH‑aplastic anemia (AA) syndrome was explored. The expression of PR3 and NB1 on CD59‑ neutrophils was detected by flow cytometry, immunofluorescence (IF), reverse transcription‑quantitative polymerase chain reaction analysis and western blotting. Serum levels of PR3, proteinase‑activated receptor 1 (PAR1) and D‑Dimer were measured using ELISAs. The expression of PR3 and NB1 on the plasma membrane of CD59‑ neutrophils in patients with PNH/PNH‑AA was significantly lower compared with their expression on CD59+ neutrophils in patients and controls (P=0.001). However, no correlation between PR3 and NB1 expression was identified. IF staining further demonstrated partially positive PR3 expression on CD59‑ neutrophils. The serum level of PR3 in patients was identified to be significantly decreased compared with healthy controls (P<0.0001), and significantly negatively correlated with PAR1 (r=‑0.456; P=0.043) and D‑Dimer (r=‑0.503; P=0.028) levels. The mRNA and protein levels of PR3 on PNH clones did not change significantly compared with the control group. In conclusion, PR3 expression on the plasma membrane of neutrophils and in the serum of patients with PNH/PNH‑AA decreased, which may result in increased PAR1 expression and increased clotting. The present study provides the basis for further study on platelets in PNH. [ABSTRACT FROM AUTHOR]