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Objective:To observe the effects of overexpression of polypyrimidine tract binding protein-associated splicing factor (PSF) on the endoplasmic reticulum (ER) oxidative stress damage of human retinal microvascular endothelial cells (hRMEC) under high concentration of 4-hydroxynonenal (4-HNE).Methods:The logarithmic growth phase hRMEC cultured in vitro was divided into normal group, simple 4-HNE treatment group (simple 4-HNE group), empty plasmid combined with 4-HNE treatment group (Vec+4-HNE group), and PSF high expression combined with 4-HNE treatment group (PSF+4-HNE group). In 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group cell culture medium, 10 μmol/L 4-HNE was added and stimulated for 12 hours. Subsequently, the Vec+4-HNE group and PSF+4-HNE group were transfected with transfection reagent liposome 2000 into pcDNA empty bodies and pcDNA-PSF eukaryotic expression plasmids, respectively, for 24 hours. Flow cytometry was used to detect the effects of 4-HNE and PSF on cell apoptosis. The effect of PSF overexpression on the expression of reactive oxygen species (ROS) in hRMEC was detected by 2', 7'-dichlorodihydrofluorescein double Acetate probe. Western blot was used to detect ER oxide protein 1 (Ero-1), protein disulfide isomerase (PDI), C/EBP homologous transcription factor (CHOP), glucose regulatory protein (GRP) 78, protein kinase R-like ER kinase (PERK)/phosphorylated PERK (p-PERK), and Eukaryotic initiation factor (eIF) 2α/the relative expression levels of phosphorylated eIF (peIF) and activated transcription factor 4 (ATF4) proteins in hRMEC of normal group, 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group. Single factor analysis of variance was performed for inter group comparison.Results:The apoptosis rates of the simple 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group were (22.50±0.58)%, (26.93±0.55)%, and (11.70±0.17)%, respectively. The intracellular ROS expression levels were 0.23±0.03, 1.60±0.06, and 0.50±0.06, respectively. The difference in cell apoptosis rate among the three groups was statistically significant ( F=24.531, P<0.05). The expression level of ROS in the Vec+4-HNE group was significantly higher than that in the simple 4-HNE group and the PSF+4-HNE group, with a statistically significant difference ( F=37.274, P<0.05). The relative expression levels of ER Ero-1 and PDI proteins in the normal group, simple 4-HNE group, Vec+4-HNE group, and PSF+4-HNE group were 1.25±0.03, 0.45±0.03, 0.63±0.03, 1.13±0.09, and 1.00±0.10, 0.27±0.10, 0.31±0.05, and 0.80±0.06, respectively. The relative expression levels of CHOP and GRP78 proteins were 0.55±0.06, 1.13±0.09, 0.90±0.06, 0.48±0.04 and 0.48±0.04, 1.25±0.03, 1.03±0.09, 0.50±0.06, respectively. The relative expression levels of Ero-1 ( F=43.164), PDI ( F=36.643), CHOP ( F=42.855), and GRP78 ( F=45.275) proteins in four groups were compared, and the differences were statistically significant ( P<0.05). Four groups of cells ER p-pERK/pERK ( F=35.755), peIF2 α/ The relative expression levels of eIF ( F=38.643) and ATF4 ( F=31.275) proteins were compared, and the differences were statistically significant ( P<0.05). Conclusion:PSF can inhibit cell apoptosis and ROS production induced by high concentration of 4-HNE, and its mechanism is closely related to restoring the homeostasis of ER and down-regulating the activation level of PERK/eIF2α/ATF4 pathway.
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Objective:To observe the effect of high expression of polypyrimidine tract-binding protein-associated splicing factor (PSF) on low concentration of 4-hydroxynonenal (4-HNE) induced human retinal microvascular endothelial cells (HRMECs), and explore the possible mechanism.Methods:The HRMECs cultured in vitro were divided into 4-HNE treated group, PSF overexpression group combined with 4-HNE group (PSF+4-HNE group), PSF overexpression+ML385 treatment combined with 4-HNE group (PSF+ML385+4-HNE group), and 4-HNE induced PSF overexpression group with LY294002 pretreatment (LY294002+4-HNE+PSF group). Cell culture medium containing 10 μmmol/L 4-HNE was added into 4-HNE treatment group, PSF+4-HNE group, PSF+ML385+4-HNE group for 12 hours to stimulate oxidative stress. 1.0 μg of pcDNA-PSF eukaryotic expression plasmid were transfected into PSF+4-HNE group and PSF+ML385+4-HNE group to achieve the overexpression of PSF. Also cells were pretreated with ML385 (5 μmol/L) for 48 hours in the PSF+ML385+4-HNE group, meanwhile within the LY294002+4-HNE+PSF group, after pretreatment with LY294002, cells were treated with plasmid transfection and 4-HNE induction. Transwell detects the migration ability of PSF to HRMECs. The effect of PSF on the lumen formation of HRMECs was detected by using Matrigel in vitro three-dimensional molding method. Flow cytometer was used to detect the effect of PSF overexpression on reactive oxygen (ROS) level in HRMECs. Protein immunoblotting was used to detect the relative expression of PSF, nuclear factor E2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1) protein, and phosphoserine threonine protein kinase (pAkt) protein. The comparison between the two groups was performed using a t-test. Results:The number of live cells, migrating cells, and intact lumen formation in the 4-HNE treatment group and the PSF+4-HNE group were 1.70±0.06, 0.80±0.13, 24.00±0.58, 10.00±0.67, and 725.00±5.77, 318.7±12.13, respectively. There were significant differences in the number of live cells, migrating cells, and intact lumen formation between the two groups ( t=12.311, 15.643, 17.346; P<0.001). The results of flow cytometry showed that the ROS levels in the 4-HNE treatment group, PSF+4-HNE group, and PSF+ML385+4-HNE group were 816.70±16.67, 416.70±15.44, and 783.30±17.41, respectively. There were statistically significant differences between the two groups ( t=16.311, 14.833, 18.442; P<0.001). Western blot analysis showed that the relative expression levels of pAkt, Nrf2, and HO-1 proteins in HRMECs in the 4-HNE treatment group, PSF+4-HNE group and LY294002+4-HNE+PSF group were 0.08±0.01, 0.57±0.04, 0.35±0.09, 0.17±0.03, 1.10±0.06, 0.08±0.11 and 0.80±0.14, 2.50±0.07, 0.50±0.05, respectively. Compared with the PSF+4-HNE group, the relative expression of pAkt, Nrf2, and HO-1 proteins in the LY294002+4-HNE+PSF group decreased significantly, with significant differences ( t=17.342, 16.813, 18.794; P<0.001). Conclusion:PSF upregulates the expression of HO-1 by activating the phosphatidylinositol 3 kinase/Akt pathway and inhibits cell proliferation, migration, and lumen formation induced by low concentrations of 4-HNE.
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Cholangiocarcinoma (CCA) is a highly invasive type of cancer with insidious onset and high mortality. Polypyrimidine tract-binding protein 1 (PTBP1) is highly over-expressed in various types of tumor tissues, which contributes to cancer progression. But the role of PTBP1 in CCA has not been explored yet. In this study, we aim to investigate the function of PTBP1 in CCA. Therefore, we used publicly available data from the cancer genome atlas (TCGA) to evaluate the dysregulation of PTBP1 in CCA. The results showed that the PTBP1 is significantly up-regulated in CCA tissues compared to the matched non-tumor tissues (P < 0. 05). We assessed the effects of PTBP1 on the growth of CCA cell lines RBE and HuH28 by performing CCK-8 and plate colony formation assays. The results showed that overexpression of PTBP1 significantly promoted the growth (P < 0. 01) of CCA cells, whereas knockdown of PTBP1 exhibited opposite effects. Transwell and Invasion assays revealed that overexpression of PTBP1 significantly promotes the migration and invasion of CCA cells (P < 0. 001), whereas knockdown of PTBP1 exhibited opposite effects (P < 0. 001). The RNA sequencing (RNA-seq) analysis in PTBP1-depleted cells showed that the up-regulated genes are significantly enriched in p53 signaling pathway, while the down-regulated genes are represented by cholesterol metabolism, Rho GTPase and TGF-β pathways. Then, the alternative splicing analysis revealed that inhibition of PTBP1 led to series of aberrant alternative splicing events, including several cancer-associated ones, such as splicing events within the TGF-β regulator TGIF1 and the p53 activity-correlated gene GNAS. These results indicate that PTBP1 promotes the progression of CCA likely by regulating the transcriptome alternative splicing to influence multiple cancer-associated signaling pathways.
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Objective To observe the protective effect of polypyrimidine bundle-binding proteinrelated splicing factor (PSF) over-expression on RPE cell injury induced by advanced glycation end products (AGEs).Methods The human RPE cells cultured in vitro were divided into three groups:normal control group (N group),blank control group (N + AGEs group),empty vector control group (Vec + AGEs group),and PSF high expression group (PSF + AGEs).group).RPE cells in N group were routinely cultured;RPE cells in N + AGEs group were only transfected but did not introduce any exogenous genes combined with AGEs induction;Vec +AGEs group and PSF + AGEs group were transfected with pcDNA The empty vector or pcDNA-PSF eukaryotic expression plasmid was introduced into RPE cells and induced by AGEs.Except the N group,the other 3 groups of cells were transfected accordingly,and were stimulated with 150 μg/ml AGEs for 72 h after 24 h.HE staining and Hoechst 33258 staining were used to observe the effect of high PSF expression on the morphological changes of RPE cells;ROS level detection was used to analyze the effect of PSF high expression on the ROS expression of RPE cells induced by AGEs;MTT colorimetric method was used to detect the high PSF expression Effects on the viability of RPE cells;Western blot was used to detect the effects of different time and dose of PSF on the expression of heme oxygenase 1 (HO-1).Results HE staining and Hoechst 33258 staining observation showed that the cells in group N were full in shape,the nucleus was round,the cytoplasm was rich,and the staining was uniform;the cells in N + AGEs group and Vec + AGEs group were reduced in size,the eosinophilic staining was enhanced,and the nucleus was densely densely stained.Pyrolysis and even fragmentation;the morphology of cells in the PSF + AGEs group was still full,the cytoplasm staining was more uniform,and the nucleus staining was uniform.The results of MTT colorimetry showed that high expression of PSF can effectively improve the viability of RPE cells,but this effect can be effectively antagonized by ZnPP,and the difference is statistically significant (F=33.26,P＜0.05).DCFH-DA test results showed that compared with the N + AGEs group and Vec + AGEs group,the ROS production in PSF + AGEs group decreased,the difference was statistically significant (F=1 1.94,P＜0.05).Western blot analysis showed that PSF protein upregulated HO-1 expression in a time-and dose-dependent manner.The relative expression level of HO-1 at 24,48,and 72 h after PSF protein was significantly higher than that at 0 h,and the difference was statistically significant (F=164.91,P＜0.05).The relative expression level of HO-1 under the action of 0.1,0.5,1.0,1.5,and 2.0 μg PSF protein was significantly higher than 0.0 μg,and the difference was statistically significant (F=104.82,P＜0.05).Conclusion PSF may inhibit the production of ROS by up-regulating the expression of HO-1,thus protecting the RPE cells induced by AGEs.
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Polypyrimidine tract-binding protein 1 (PTBP1) plays an essential role in splicing and is expressed in almost all cell types in humans, unlike the other proteins of the PTBP family. PTBP1 mediates several cellular processes in certain types of cells, including the growth and differentiation of neuronal cells and activation of immune cells. Its function is regulated by various molecules, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and RNA-binding proteins. PTBP1 plays roles in various diseases, particularly in some cancers, including colorectal cancer, renal cell cancer, breast cancer, and glioma. In cancers, it acts mainly as a regulator of glycolysis, apoptosis, proliferation, tumorigenesis, invasion, and migration. The role of PTBP1 in cancer has become a popular research topic in recent years, and this research has contributed greatly to the formulation of a useful therapeutic strategy for cancer. In this review, we summarize recent findings related to PTBP1 and discuss how it regulates the development of cancer cells.
Subject(s)
Humans , Alternative Splicing , Carcinogenesis , Glycolysis , Heterogeneous-Nuclear Ribonucleoproteins/physiology , MicroRNAs/physiology , Neoplasms/pathology , Polypyrimidine Tract-Binding Protein/physiology , RNA, Long Noncoding/physiologyABSTRACT
Polypyrimidine tract-binding protein 1 (PTBP1) plays an essential role in splicing and is expressed in almost all cell types in humans, unlike the other proteins of the PTBP family. PTBP1 mediates several cellular processes in certain types of cells, including the growth and differentiation of neuronal cells and activation of immune cells. Its function is regulated by various molecules, including microRNAs (miRNAs), long non-coding RNAs (IncRNAs), and RNA-binding proteins. PTBP1 plays roles in various diseases, particularly in some cancers, including colorectal cancer, renal cell cancer, breast cancer, and glioma. In cancers, it acts mainly as a regulator of glycolysis, apoptosis, proliferation, tumorigenesis, invasion, and migration. The role of PTBP1 in cancer has become a popular research topic in recent years, and this research has contributed greatly to the formulation of a useful therapeutic strategy for cancer. In this review, we summarize recent findings related to PTBP1 and discuss how it regulates the development of cancer cells.
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Objective To observe the effect ofpolypyramidine tract binding protein-associated splicing factor (PSF) towards advanced glycation end products (AGEs) induced the apoptosis of Müller cells in vitro.Methods Experimental study.Müller cells were cultured and divided into groups according to the project design,plasmid enhanced green fluorescent protein-PSF were transfected into the cells to achieve the overexpression of PSF Müller cells in vitro,then cells were exposed to AGEs and the Morphological changes were observed by HE staining and Hoechst 33258 staining while the survival rate of cells were detected by MTT assay.The effects of PSF on AGEs-induced Müller apoptosis was measured by Cell Death Detection ELISA kit.Meanwhile,2',7'-diehlorofluorescin diaeetate staining was performed to monitor the protective effects of PSF on AGEs-induced Müller cells ROS.Results The morphology of cells in normal group was full and the cytoplasm staining was uniform.In N+AGEs group and Vec+AGEs group,cell volume decreased,cytoplasm was dense and concentrated,and eosinophilic staining was enhanced.The cell morphology of PSF+AGEs group was still full,with uniform cytoplasm staining and uniform nucleus staining.The viability of N+AGEs group,Vec+AGEs group and PSF+AGEs group were 0.42±0.11,0.35±0.12 and 0.68±0.12.The apoptosis values were 1.08 ± 0.16,0.96± 0.20 and 0.44± 0.08.The intracellular ROS levels were 28 833.67± 3 550.06,28 356.67±4 854.81,186 163.00±382.54.Compared with N+AGEs group and Vec+AGEs group,the cell viability of PSF+AGEs group was significantly improved (F=20.65,P=0.000),ce11 apoptosis value (F=43.43,P=0.000) and intracellular ROS level (F=1 8.86,P=0.000).Conclusion PSF overexpression play a protective role in AGEs-induced apoptosis by inhibiting the production of ROS in Müiller cells.
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Objective To observe the effect ofpolypyramidine tract binding protein-associated splicing factor (PSF) on hydrogen peroxide (H2O2) induced apoptosis of retinal pigment epithelial (RPE) cells in vitro.Methods RPE cells were cultured and divided into a normal group,normal+H2O2 group,Vec+H2O2 group,PSF+H2O2 group according to the experimental design.Overexpression of PSF in RPE cells were achieved by pEGFP-PSF plasmid transient transfection into RPE cells,then RPE cells were exposed to H2O2.The morphological changes were observed by hematoxylin-eosin (HE) staining and Live/Dead staining while the survival rate of cells was detected by MTT assay.The effect of PSF on H2O2-induced RPE apoptosis was analyzed by Cell Death Detection ELISA kit.Meanwhile,intracellular reactive oxygen species (ROS) level was detected by using DCFH-DA method.Results Overexpression of PSF could effectively alleviate the morphological changes induced by H2O2 stimulation shown by HE staining,and effectively reduce dead cells number shown by Live/Dead staining.After H2O2 stimulation,the survival rate,apoptosis rate and ROS production level in PSF overexpression group were 0.68± 0.12,0.44± 0.08 and 18 616± 3 382.54 respectively,showing significant difference in comparison with the vector plasmid group and normal group (P＜0.05).Conclusion PSF overexpression plays a protective role in H2O2-induced apoptosis by inhibiting the production of ROS in RPE cells.
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RNA binding proteins (RBPs) regulate the function of cells by interacting with nascent transcripts and therefore are receiving increasing attention from researchers for their roles in tissue development and homeostasis. The polypyrimidine tract binding (PTB) protein family of RBPs are important posttranscriptional regulators of gene expression. Further investigations on the post-transcriptional regulation mechanisms and isoforms of PTB proteins in the spermatogenesis show that PTB protein 1 (Ptbp1) is a predominant isoform in mitotic cells (spermatogonia), while Ptbp2 predominates in meiotic spermatocytes and postmeiotic spermatids and binds to the specific 3' untranslated region (3' UTR) of the phosphoglycerate kinase 2 (Pgk-2) mRNA, which helps to stabilize Pgk-2 mRNA in male mouse germ cells. In case of Ptbp2 inactivation in the testis, the differentiation of germ cells arrests in the stage of round spermatids, with proliferation of multinucleated cells in the seminiferous tubule, increased apoptosis of spermatocytes, atrophy of seminiferous tubules, and lack of elongating spermatids, which consequently affects male fertility. This article presents an overview on the structure of the PTB protein and its role in regulating mammalian spermatogenesis.
Subject(s)
Animals , Male , Mice , Atrophy , Gene Expression Regulation , Physiology , Heterogeneous-Nuclear Ribonucleoproteins , Metabolism , Physiology , Homeostasis , Isoenzymes , Metabolism , Nerve Tissue Proteins , Metabolism , Physiology , Phosphoglycerate Kinase , Metabolism , Polypyrimidine Tract-Binding Protein , Metabolism , Physiology , RNA, Messenger , Metabolism , RNA-Binding Proteins , Seminiferous Tubules , Pathology , Spermatids , Metabolism , Spermatocytes , Metabolism , Spermatogenesis , Physiology , Spermatogonia , Metabolism , Testis , MetabolismABSTRACT
Polypyrimidine tract-binding protein 1 (PTBP1) is involved in almost all steps of mRNA metabolism,including alternative splicing due to its RNA-binding activity.PTBP1 regulates alternative splicing and levels of mRNA of its target genes,which directly contributes to the malignant phenotype during tumorigenesis.PTBP1 is a potential tumor markers for cancer diagnosis.
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Leishmania (Sauroleishmania) tarentolae has biotechnological potential for use as live vaccine against visceral leishmaniasis and as a system for the over expression of eukaryotic proteins that possess accurate post-translational modifications. For both purposes, new systems for protein expression in this non-pathogenic protozoan are necessary. The ribosomal RNA promoter proved to be a stronger transcription driver since its use yielded increased levels of recombinant protein in organisms of both genera Trypanosoma or Leishmania. We have evaluated heterologous expression systems using vectors with two different polypyrimidine tracts in the splice acceptor site by measuring a reporter gene transcribed from L. tarentolae RNA polymerase I promoter. Our data indicate that the efficiency of chloramphenicol acetyl transferase expression changed drastically with homologous or heterologous sequences, depending on the polypyrimidine tract used in the construct and differences in size and/or distance from the AG dinucleotide. In relation to the promoter sequence the reporter expression was higher in heterologous lizard-infecting species than in the homologous L. tarentolae or in the mammalian-infecting L. (Leishmania) amazonensis.
Subject(s)
Animals , Promoter Regions, Genetic , Leishmania/genetics , RNA Polymerase I/genetics , RNA Splice Sites/genetics , Gene Expression , Leishmania/classificationABSTRACT
In order to demonstrate PTB bind to HPRE,reverse transcription,PCR-mediated detection,were used.HepG2.2.15 cell line and HBs-HPRE transient expression cells were adopted to identify PTB function in HBV life cycle.The results showed that PTB could directly bind to HPRE RNA.Functional analysis indicated that PTB could inhibit the expression of HBs antigen and this inhibition was in a dose-dependent manner in HepG2.2.15 cells.Higher expression of HBs in cells transfected pcDNA3-HBs-HPRE comparing with pcDNA3-HBs,and this high expression could also be inhibited by PTB.The data demonstrated that PTB inhibits HBs expression by interacting with HPRE.