Endocytosis is differentially regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) and phospholipase D (PLD). However, the relationship between HIF-1alpha and PLD in endocytosis is unknown. HIF-1alpha is degraded through the prolyl hydroxylase (PHD)/von Hippel-Lindau (VHL) ubiquitination pathway in an oxygen-dependent manner. Here, we show that PLD1 recovers the decrease in epidermal growth factor receptor (EGFR) endocytosis induced by HIF-1alpha independent of lipase activity via the Rab5-mediated endosome fusion pathway. EGF-induced interaction of PLD1 with HIF-1alpha, PHD and VHL may contribute to EGFR endocytosis. The pleckstrin homology domain (PH) of PLD1 itself promotes degradation of HIF-1alpha, then accelerates EGFR endocytosis via upregulation of rabaptin-5 and suppresses tumor progression. These findings reveal a novel role of the PLD1-PH domain as a positive regulator of endocytosis and provide a link between PLD1 and HIF-1alpha in the EGFR endocytosis pathway.
Animals ; Blood Proteins/chemistry/*metabolism ; Endocytosis ; Female ; HEK293 Cells ; HT29 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism ; Mice, Nude ; Neoplasms/genetics/metabolism/pathology ; Phospholipase D/chemistry/*metabolism ; Phosphoproteins/chemistry/*metabolism ; Protein Structure, Tertiary ; Receptor, Epidermal Growth Factor/*metabolism ; Signal Transduction ; *Up-Regulation ; Vesicular Transport Proteins/*genetics/metabolism ; rab5 GTP-Binding Proteins/*metabolism

OBJECTIVE: To clarify the effect of glycosylphosphatidylinositol-specific phospholipase D (GPIPLD) on hepatoma cells HepG2 and the possible molecular mechanism. METHODS: MTT, fluorescent staining and Western blot were applied to analyze the effect and molecular mechanism of GPI-PLD on hepatoma cells by transfected high expression GPI-PLD model. We inoculated HepG2 in nude mice models to further clarify the effect of GPI-PLD on hepatoma cells in vivo. RESULTS: Compared with the control groups, PI3K-Akt signaling pathway activity and proliferation of hepatoma cells were significantly inhibited in the GPI-PLD group. Nude mice models showed that the tumor growth and tumor weight [(1.87 ± 0.09) g] of the GPI-PLD group were significantly less than those of the blank control group [(2.20 ± 0.17) g] and the negative control group [(2.15 ± 0.09) g]. AST, ALT and AFP serum concentration in the GPI-PLD group were significantly lower than those of the control groups (P<0.05). CONCLUSION GPI-PLD can inhibit the proliferation of hepatoma cells and growth in vivo, and promote the apoptosis of hepatoma cells by reducing the activity of PI3K-Akt signaling pathway.
Animals ; Apoptosis ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Line ; Down-Regulation ; Hep G2 Cells ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Mice ; Mice, Nude ; Phosphatidylinositol 3-Kinases ; Phospholipase D ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; Transfection

The development of a serological marker for early diagnosis of isocyanate-induced occupational asthma (isocyanate-OA) may improve clinical outcome. Our previous proteomic study found that expression of vitamin D-binding protein (VDBP) was upregulated in the patients with isocyanate-OA. In the present study, we evaluated the clinical relevance of VDBP as a serological marker in screening for isocyanate-OA among exposed workers and its role in the pathogenesis of isocyanate-OA. Three study groups including 61 patients with isocyanate-OA (group I), 180 asymptomatic exposed controls (AECs, group II), 58 unexposed healthy controls (NCs, group III) were enrolled in this study. The baseline serum VDBP level was significantly higher in group I compared with groups II and III. The sensitivity and specificity for predicting the phenotype of isocyanate-OA with VDBP were 69% and 81%, respectively. The group I subjects with high VDBP (> or = 311 microg/ml) had significantly lower PC20 methacholine levels than did subjects with low VDBP. The in vitro studies showed that TDI suppressed the uptake of VDBP into RLE-6TN cells, which was mediated by the downregulation of megalin, an endocytic receptor of the 25-hydroxycholecalciferol-VDBP complex. Furthermore, toluene diisocyanate (TDI) increased VEGF production and secretion from this epithelial cells by suppression of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] production. The findings of this study suggest that the serum VDBP level may be used as a serological marker for the detection of isocyanate-OA among workers exposed to isocyanate. The TDI-induced VEGF production/secretion was reversed by 1,25(OH)2D3 treatment, which may provide a potential therapeutic strategy for patients with isocyanate-OA.
Adult ; Animals ; *Asthma/blood/chemically induced/pathology ; Cell Line ; Epithelial Cells ; Female ; Gene Expression/drug effects ; Humans ; Isocyanates/toxicity ; Male ; Middle Aged ; *Occupational Diseases/blood/chemically induced/pathology ; Rats ; Toluene 2,4-Diisocyanate/toxicity ; Vitamin D-Binding Protein/*blood

BACKGROUND: Myelomatous pleural effusion (MPE) is rare in myeloma patients. We present a consecutive series of patients with MPE in a single institution. METHODS: We retrospectively reviewed the medical records of 19 patients diagnosed with MPE between 1989 and 2008 at the Asan Medical Center. Diagnoses were confirmed by cytologic identification of malignant plasma cells in the pleural fluid. RESULTS: Our patients showed dominance of IgA (36.8%) and IgD (31.6%) subtypes. Of 734 myeloma patients, the incidence of MPE was remarkably high for the IgD myeloma subtype (16.7%), compared to the other subtypes (1.4% for IgG and 4.6% for IgA). At the time of diagnosis of MPE, elevated serum beta2-microglobulin, anemia, elevated serum lactate dehydrogenase, and elevated creatinine levels were found in 100%, 89.5%, 83.3%, and 57.9% of the patients, respectively. Approximately one-third (31.3%) of the patients had adenosine deaminase (ADA) activities in their pleural fluid exceeding the upper limit of the reported cutoff values for tuberculous pleural effusion (55.8 U/L). Chromosome 13 abnormality was seen in 77.8% of the tested patients. The median survival period from the development of MPE was 2.8 months. CONCLUSIONS: Patients with MPE have aggressive clinical and laboratory characteristics. The preponderance of IgD myeloma in MPE patients is a noteworthy finding because IgD myeloma is a rare subtype. Elevated ADA activity in the pleural fluid is also noteworthy, and may be helpful for detecting MPE. Physicians treating myeloma patients should monitor the development of MPE and consider the possibility of a worse clinical course.
Adenosine Deaminase/metabolism ; Adult ; Aged ; Chromosomes, Human, Pair 13 ; Creatine/blood ; Diagnosis, Differential ; Female ; Humans ; Immunoglobulin A/metabolism ; Immunoglobulin D/metabolism ; L-Lactate Dehydrogenase/blood ; Male ; Middle Aged ; Multiple Myeloma/diagnosis ; Plasma Cells/pathology ; Pleural Effusion, Malignant/*diagnosis/mortality/pathology ; Retrospective Studies ; Survival Rate ; beta 2-Microglobulin/blood

This study was purposed to investigate the expression and significance of glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) in bone marrow mononuclear cells (BMMNC) isolated from patients with acute myeloid leukemia (AML), GPI-PLD activity in BMMNC isolated from 78 patients with AML and 15 normal persons was measured by using GPI-anchored placental alkaline phosphatase (PLAP) as a substrate and Triton X-114 phase partitioning. The GPI-PLD mRNA expression was measured by semi-quantitive reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the mRNA expression level and activity of GPI-PLD in BMMNC from de novo AML patients were 1.86 +/- 0.32 and 46.96 +/- 7.15% respectively; the mRNA expression level and activity of GPI-PLD in BMMNC from completely remission and refractory or relapsed patients were 1.26 +/- 0.29, 33.36 +/- 5.13%and 1.79 +/- 0.19, 44.31 +/- 7.22%, while those in BMMNC from normal controls were 1.27 +/- 0.23, 35.38 +/- 5.15% respectively. The mRNA expression level and activity of GPI-PLD in de novo and refractory or relapsed patients were obviously higher than those in normal controls with significant difference (p < 0.01), while the comparison between remitted patients and normal controls showed no statistical difference (p > 0.05). It is concluded that the expression level of GPI-PLD mRNA coincides with GPI-PLD activity. The mRNA expression and activity of GPI-PLD in de novo and refractory or relapsed patients are obviously higher than those in normal controls. It is worthy of further exploring whether GPI-PLD plays a certain role in process of leukemia pathogenesis.
Adolescent ; Adult ; Bone Marrow Cells ; cytology ; metabolism ; Case-Control Studies ; Child ; Female ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Male ; Middle Aged ; Phospholipase D ; genetics ; metabolism ; RNA, Messenger ; genetics ; Young Adult

OBJECTIVETo investigate the relationship between the excitotoxicity and serum-inducible kinase (SNK) and spine-associated Rap GTPase-activating protein (SPAR) pathway in primary hippocampal neuron injury induced by glutamate and furthermore, to explore the molecular mechanism of neuroprotection of Zibu Piyin Recipe (ZBPYR) and the relationship between ZBPYR and the morphological regulation of dendritic spines.

METHODSThe serum containing ZBPYR was prepared by seropharmacology. Reverse transcription and polymerase chain reaction (RT-PCR) was used to detect the expression of mRNA for SNK, SPAR, postsynaptic density protein 95 (PSD-95) and N-methyl-D-aspartate (NMDA) receptor subunits (NR1, NR2A and NR2B) in primary rat hippocampal neuron cultures after pretreatment with 10 micromol/L glutamate and ZBPYR serum.

RESULTSZBPYR serum pretreatment resulted in a significant down-regulation of glutamate-induced SNK mRNA expression (P<0.05). Significant up-regulation was seen on the mRNA expression of SPAR and PSD-95 (P<0.05). All these changes were dose-dependent. The mRNA expression of NR1, NR2A and NR2B was down-regulated to different degrees (P<0.05).

CONCLUSIONThe mechanism of effect of ZBPYR on glutamate-induced excitotoxicity may be related to the regulation of SNK-SPAR signal pathway. ZBPYR may play a role in protecting and maintaining the normal morphology and structure of dendritic spines, which may be achieved by inhibiting the excessive activation of NMDA receptors.

Animals ; Cells, Cultured ; Disks Large Homolog 4 Protein ; Drugs, Chinese Herbal ; pharmacology ; GTPase-Activating Proteins ; genetics ; metabolism ; Gene Expression Regulation ; drug effects ; Glutamic Acid ; toxicity ; Hippocampus ; drug effects ; enzymology ; pathology ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Membrane Proteins ; genetics ; metabolism ; Neurons ; drug effects ; enzymology ; pathology ; Protein Kinases ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Serum

OBJECTIVE: To investigate the effect of overexpression of glycosylphosphatidyl-inositol-specific phospholipase D (GPI-PLD) on the biological character of hepatocellular carcinoma cell line HepG2. METHODS: The GPI-PLD gene eukaryon expression vector pcDNA3.1(+)/ GPI-PLD was transiently transfected into HepG2 cell by lipid-media transfection. The untransfected HepG2 and HepG2 transfected with pcDNA3.1(+) were used as controls. After screening with G418, the single clone was obtained. The expression level of GPI-PLD mRNA in HepG2 was identified by reverse transcription polymerase chain reaction (RT-PCR). GPI-PLD activities were analyzed quantitatively by triton-X-114 partition with GPI anchored placental alkaline phosphatase (PLAP) as a substrate. Cell count was used to detect the proliferation of the 3 groups, and complement dependent cytotoxicity (CDC) effects were observed by the staining of trypan blue. Apoptosis cells were analyzed by flow cytometry. Carcinoembryonic antigen (CEA)was detected by enzyme linked immunosorbent assay (ELISA). RESULTS: Compared with HepG2 and pcDNA3.1(+)/HepG2 cell, the levels of GPI-PLD activities and its mRNA from pcDNA3.1(+)/GPI-PLD/HepG2 were increased with almost 2 to 5 times,respectively. The GPI anchored PLAP and CEA released into the medium by GPI-PLD, and the rate of CDC killing on the cells were significantly increased. However, the proliferative capacity was obviously decreased, and the typical apoptosis cells were presented in positive clones and its apoptosis rates were increased significantly. CONCLUSION The stable cell line with overexpression of GPI-PLD has been constructed. The overexpression of GPI-PLD in these cells increases the sensitivity of these cells to CDC killing and impairs the proliferative capacity of cells, and promotes the apoptosis.
Apoptosis ; genetics ; Carcinoma, Hepatocellular ; genetics ; pathology ; Complement Activation ; genetics ; Cytotoxicity, Immunologic ; genetics ; Eukaryotic Cells ; metabolism ; Genetic Vectors ; genetics ; metabolism ; Humans ; Liver Neoplasms ; genetics ; pathology ; Phospholipase D ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Transfection ; Tumor Cells, Cultured ; Up-Regulation

OBJECTIVETo study the role of N-methyl-D-aspartate receptor and Ca(2+) in acute intoxicated encephalopathy induced by 1, 2-dichloroethane (1, 2-DCE) in vitro.

METHODSNeurocytes of new born rats were cultured in vitro, which were administered with different doses of 1, 2-DCE, and NMDAR and Ca(2+) antagonists including Ketamine and Nimodiping respectively. The cell morphologic structures were observed under light microscope, and its proliferation was detected by Cell Counting Kit-VIII.

RESULTS1, 2-DCE could damage the normal morphological structure of neurocytes: the cell body swelled and broke down, the karyon slurred or disappeared, the axone became shorten and thick, connection of neurocytes was reduced, the cell membrane was half-baked, injury of neurocytes became severer with the increase of the dose of 1, 2-DCE. There was no statistical difference in the proliferation of neurocytes between every 1, 2-DCE groups (P > 0.05), but there was significantly statistical difference between 1, 2-DCE groups, the control group, and the retarder groups (P < 0.01).

CONCLUSION1, 2-DCE can damage the normal morphological structure of neurocytes, and the damage will become severer with the increase of the dose of 1, 2-DCE. However, the cell morphologic structures and proliferation of antagonist groups are much better than those in the 1, 2-DCE groups.

Animals ; Calcium ; antagonists & inhibitors ; physiology ; Cells, Cultured ; Ethylene Dichlorides ; toxicity ; Neurons ; drug effects ; pathology ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; antagonists & inhibitors ; physiology

OBJECTIVETo investigate the effects of HCMV infection on phenotypes of parotid duct epithelial cells and relative mechanisms.

METHODSThe expressions of immediate early antigen of HCMV, pan cytokeratin and cathepsin D etc. were detected by immunohistochemical staining in tissues of parotid cytomegalic inclusion disease.

RESULTSCytokeratin which acts as an epithelial marker became negative while staining of Cathepsin D was intensified in parotid duct epithelial cells after infected by HCMV.

CONCLUSIONIt demonstrated that cytokeratin was lost through over-expression of Cathepsin D in parotid duct epithelial cells infected by HCMV.

Animals ; Antigens, CD ; analysis ; Antigens, Differentiation, Myelomonocytic ; analysis ; Antigens, Viral ; analysis ; Cathepsin D ; analysis ; Cytomegalovirus ; immunology ; physiology ; Cytomegalovirus Infections ; metabolism ; pathology ; virology ; Desmin ; analysis ; Epithelial Cells ; metabolism ; pathology ; virology ; Female ; Glial Fibrillary Acidic Protein ; analysis ; Host-Pathogen Interactions ; Humans ; Immunohistochemistry ; Infant ; Keratins ; analysis ; Male ; Mice ; Salivary Ducts ; metabolism ; pathology ; virology ; Vimentin ; analysis

To explore the effect of glycosyl-phosphatidyl inositol-specific phospholipase D (GPI-PLD) on the adhesion function of bone marrow mononuclear cell from patients with myeloid leukemia and analyze its mechanism, the activity of GPI-PLD in bone marrow mononuclear cell from the patients were measured by using GPI-anchored placental alkaline phosphatase (PLAP) as substrate and Triton-X114 partitioning; the adhesion rate and CD24 expression of these cells were measured by MTT and immunohistochemical method respectively, when these cells were or were not treated by 1 mmol/L 1,10-phenanthroline for 5 hours. The results showed that the GPI-PLD activity of bone marrow mononuclear cells from the patients was significantly inhibited after being treated by 1 mmol/L 1, 10-phenanthroline for 5 hours [(42.08 +/- 7.21)% vs (5.4 +/- 2.96)%], while the adhesion rate and the expression of CD24 of these cells were increased [(49.78 +/- 26.73)% vs (61.19 +/- 29.14)%, (16.02 +/- 9.68)% vs (18.5 +/- 11.14)%, respectively)]. It is concluded that depression of GPI-PLD activity can increase the adhesion rate of bone marrow mononuclear cells from the patients while the CD24 expression is enhanced.
Adolescent ; Adult ; Aged ; Bone Marrow Cells ; drug effects ; metabolism ; pathology ; CD24 Antigen ; biosynthesis ; Cell Adhesion ; drug effects ; Cell Survival ; drug effects ; Child ; Female ; Humans ; Immunohistochemistry ; Leukemia, Myeloid ; blood ; Leukocytes, Mononuclear ; drug effects ; metabolism ; pathology ; Male ; Middle Aged ; Phenanthrolines ; pharmacology ; Phospholipase D ; blood ; metabolism