Interaction between PSF and cytokeratin 18 mediates PSF relocation to cell membrane and maintains chemosensitivity of myeloid leukemia / 北京大学学报(医学版)

OBJECTIVE@#To identify the chaperone of polypyrimidine tractor-binding protein-associated splicing factor (PSF) in myeloid leukemia cells, and to explore the mechanism and redistributive pattern to cell surface of PSF in chemo-sensitive HL60 cells and resistant HL60/DOX cells.@*METHODS@#The eukaryotic expression vector of PSF was transfected with liposomes transiently, then flow cytometry was used to detect the expression level of PSF on the cell surface 24 h, 48 h and 72 h after vector transfections. We constructed a chimeric expression vector, streptavidin binding peptide (SBP)-PSF, meanwhile this vector was transfected and made SBP-PSF fusion protein overexpress. In addition, we used streptavidin magnetic beads to precipitate the cellular chaperonin of PSF and then identified its chaperonin by mass spectrometry (MS). Lentiviral vectors containing cytokeratin18 (K18) interference sequences were transfected into 293T cells to prepare lentivirus. HL60 and HL60/DOX cells were infected with lentivirus to obtain stable interfering K18 cell lines. Next, flow cytometry was used to test the membrane relocation level of PSF. Together, these methods confirmed the similar or different mechanisms of the PSF redistributing to membrane synergistically mediated by K18 in HL60 and HL60/DOX cells.@*RESULTS@#The expression of membrane relocated PSF was detected every day for three days (at the end of 24 h, 48 h and 72 h) after transient overexpression. The expressing rate of PSF on the cell surface was 22.4%±3.5%, 37.9%±6.0%, 58.3%±8.8%, respectively in sensitive HL60 cells, while that was 4.7%±0.5%, 3.9%±0.6%, 2.9%±0.6% , respectively in resistant HL60/DOX cells. The difference of expressing rate on each day was significant, P<0.01. We identified K18 detected by co-immunoprecipitation and mass spectrum assay which was the cellular chaperone of PSF. We found that K18 knockdown decreased the PSF expression level which redistributed on cell surface from 48.9%±5.4% to 6.2%±1.0% in sensitive HL60 cells, and from 9.11%±1.2% to 2.21%±0.51% in resistant HL60/DOX cells, respectively.@*CONCLUSION@#K18 is the intracellular chaperonin of PSF. The interaction of PSF and K18 mediates its redistribution to cell membrane in sensitive cells. While in resistant cells, PSF failed to relocate at the cell surface and accumulated in cells, which mediated resistance to chemotherapeutics.

Expression of M30 and M65 in celiac disease. Analytical cross-sectional study

ABSTRACT BACKGROUND: The role of villous atrophy in apoptosis, a distinctive feature of celiac disease, is a matter of controversy. The aim of this study was to determine the apoptosis rate through immunohistochemical staining for M30 and M65 in celiac disease cases. DESIGN AND SETTING: Analytical cross-sectional study in a tertiary-level center. METHODS: Duodenal biopsies from 28 treatment-naive patients with celiac disease, 16 patients with potential celiac disease, 10 patients with a gluten-free diet and 8 controls were subjected to immunohistochemical staining for the end-apoptotic marker M30 and the total cell death marker M65. H-scores were compared. Several laboratory parameters were recorded concomitantly, and at the one-year follow-up for celiac disease and potential celiac disease patients. RESULTS: There was a significant difference in H-score for M30 expression between the celiac disease, potential celiac disease and gluten-free diet groups (P = 0.009). There was no significant difference in H-score for M65 expression. There was a positive correlation between the H-score for M30 expression and the anti-tissue transglutaminase immunoglobulin A (anti-tTgIgA) and anti-tissue transglutaminase immunoglobulin G (anti-tTgIgG) levels (R = 0.285, P = 0.036; and R = 0.307, P = 0.024, respectively); and between the H-score for M65 expression and the anti-tTgIgA and anti-tTgIgG levels (R = 0.265, P = 0.053; and R=0.314, P = 0.021, respectively). There was no difference between celiac disease and potential celiac disease patients regarding the laboratory parameters selected. CONCLUSION: The rates of apoptosis and nutritional deficiencies in patients with potential celiac disease were similar to those in patients with celiac disease.