Panax species are mostly valuable medicinal plants. While some species' seeds are sensitive to dehydration, the dehydration tolerance of seeds from other Panax species remains unclear. The phospholipase D(PLD) gene plays an important role in plant responses to dehydration stress. However, the characteristics of the PLD gene family and their mechanisms of response to dehydration stress in seeds of Panax species with different dehydration tolerances are not well understood. This study used seeds from eight Panax species to measure the germination rates and PLD activity after dehydration and to analyze the correlation between dehydration tolerance and seed traits. Bioinformatics analysis was also conducted to characterize the PnPLD and PvPLD gene families and to evaluate their expression patterns under dehydration stress. The dehydration tolerance of Panax seeds was ranked from high to low as follows: P. ginseng, P. zingiberensis, P. quinquefolius, P. vietnamensis var. fuscidiscus, P. japonicus var. angustifolius, P. japonicus, P. notoginseng, and P. stipuleanatus. A significant negative correlation was found between dehydration tolerance and seed shape(three-dimensional variance), with flatter seeds exhibiting stronger dehydration tolerance(r=-0.792). Eighteen and nineteen PLD members were identified in P. notoginseng and P. vietnamensis var. fuscidiscus, respectively. These members were classified into five isoforms: α, β, γ, δ, and ζ. The gene structures, subcellular localization, physicochemical properties, and other characteristics of PnPLD and PvPLD were similar. Both promoters contained regulatory elements associated with plant growth and development, hormone responses, and both abiotic and biotic stress. During dehydration, the PLD enzyme activity in P. notoginseng seeds gradually increased as the water content decreased, whereas in P. vietnamensis var. fuscidiscus, PLD activity first decreased and then increased. The expression of PLDα and PLDδ in P. notoginseng seeds initially increased and then decreased, whereas in P. vietnamensis var. fuscidiscus, the expression of PLDα and PLDδ consistently decreased. In conclusion, the dehydration tolerance of Panax seeds showed a significant negative correlation with seed shape. The dehydration tolerance in P. vietnamensis var. fuscidiscus and dehydration sensitivity of P. notoginseng seeds may be related to differences in PLD enzyme activity and the expression of PLDα and PLDδ genes. This study provided the first systematic comparison of dehydration tolerance in Panax seeds and analyzed the causes of tolerance differences and the optimal water content for long-term storage at ultra-low temperatures, thus providing a theoretical basis for the short-term and ultra-low temperature long-term storage of medicinal plant seeds with varying dehydration tolerances.
Seeds/metabolism* ; Panax/physiology* ; Plant Proteins/metabolism* ; Gene Expression Regulation, Plant ; Phospholipase D/metabolism* ; Plants, Medicinal/enzymology* ; Germination ; Multigene Family ; Water/metabolism* ; Dehydration ; Phylogeny

OBJECTIVES: Systemic lupus erythematosus (SLE) is a kind of autoimmune inflammatory connective tissue disease which seriously endangers human health. Genetic factors play a key role in the pathogenesis of SLE. This study aims to investigate a novel phospholipase D2 (PLD2) mutation associated with familial SLE, and further explore the underlying mechanism of the mutation in SLE. METHODS: The blood samples from a SLE patient, the patient's parents, and 147 normal controls were collected and DNA was extracted. Whole genome high-throughput sequencing was performed in the patient and her parents and the results were further analyzed by various bioinformatics methods. The wild type (wt), mutant type (mu), and negative control PLD2 plasmids were further constructed and transfected into 293 cells. The expression level of HRAS protein in 293 cells was detected by Western blotting. RESULTS: In this SLE family, the female SLE patient and her mother, 1 in generation II and 1 in generation III had typical clinical manifestations of SLE, and all of them had lupus nephritis at early stage. The genetic characteristics are consistent with autosomal dominant inheritance. A novel PLD2 heterozygous mutation (c.2722C>T) was found in the patient and her mother, but not in her father and other normal controls. Compared with wtPLD2 plasmid and negative control PLD2 plasmid, the expression of HRAS in 293 cells transfected with muPLD2 plasmid was significantly up-regulated (both CONCLUSIONS PLD2 c.2722C>T mutation may be one of the pathogeny of SLE in this family.
Case-Control Studies ; Female ; High-Throughput Nucleotide Sequencing ; Humans ; Lupus Erythematosus, Systemic/genetics* ; Lupus Nephritis ; Mutation ; Phospholipase D

OBJECTIVETo assess the association of polymorphisms of N-acyl-phosphatidylethanolamine-phospholipase D (DAPE-PLD) and fatty acid amide hydrolase (FAAH) genes, as well as their interaction, with schizophrenia.

METHODSPolymorphisms of NAPE-PLD rs12540583 and FAAH rs324420, rs2295633, and rs6429600 were determined with PCR - restriction fragment length polymorphism assay and Sanger sequencing. The genotypes of 345 subjects of Han Chinese origin diagnosed with schizophrenia and a 403 controls were compared. The results were analyzed with SPSS 17.0, and the interaction of the two genes was analyzed using a multifactor dimensionality reduction (MDR) method.

RESULTSThe frequency of NAPE-PLD rs12540583 polymorphism was significantly different between the two groups under both dominant and additive models (χ2=17.18 vs. χ2=18.94, P<0.0125). The frequencies of AC genotype and C allele of the patient group at rs12540583 were higher than those of the controls, and the interaction of NAPE-PLD and FAAH was associated with schizophrenia. A four-loci model (rs12540583, rs324420, rs2295633 and rs6429600) can best model the interaction between NAPE-PLD and FAAH.

CONCLUSIONThe AC genotype and C allele of NAPE-PLD rs12540583 locus are risk factors for schizophrenia, and the interaction between NAPE-PLD rs12540583 and FAAH rs324420, rs2295633 and rs6429600 is associated with schizophrenia.

Adult ; Amidohydrolases ; genetics ; Asian Continental Ancestry Group ; genetics ; China ; ethnology ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Phospholipase D ; genetics ; Polymorphism, Genetic ; Schizophrenia ; genetics

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

Hypoxia-inducible factor-1alpha (HIF-1alpha) is a key transcriptional mediator that coordinates the expression of various genes involved in tumorigenesis in response to changes in oxygen tension. The stability of HIF-1alpha protein is determined by oxygen-dependent prolyl hydroxylation, which is required for binding of the von Hippel-Lindau protein (VHL), the recognition component of an E3 ubiquitin ligase that targets HIF-1alpha for ubiquitination and degradation. Here, we demonstrate that PLD2 protein itself interacts with HIF-1alpha, prolyl hydroxylase (PHD) and VHL to promote degradation of HIF-1alpha via the proteasomal pathway independent of lipase activity. PLD2 increases PHD2-mediated hydroxylation of HIF-1alpha by increasing the interaction of HIF-1alpha with PHD2. Moreover, PLD2 promotes VHL-dependent HIF-1alpha degradation by accelerating the association between VHL and HIF-1alpha. The interaction of the pleckstrin homology domain of PLD2 with HIF-1alpha also promoted degradation of HIF-1alpha and decreased expression of its target genes. These results indicate that PLD2 negatively regulates the stability of HIF-1alpha through the dynamic assembly of HIF-1alpha, PHD2 and VHL.
Cell Line ; HEK293 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/*metabolism ; Phospholipase D/*metabolism ; Prolyl Hydroxylases/metabolism ; Proteasome Endopeptidase Complex/*metabolism ; *Protein Interaction Maps ; Proteolysis ; Ubiquitin-Protein Ligases/metabolism ; Von Hippel-Lindau Tumor Suppressor Protein/metabolism

MicroRNAs (miRNAs) are a type of small non-coding RNAs that are often play important roles in carcinogenesis, but the carcinogenic mechanism of miRNAs is still unclear. This study will investigate the function and the mechanism of miR-638 in carcinoma (GC). The expression of miR-638 in GC and the DNA copy number of miR-638 were detected by real-time PCR. The effect of miR-638 on cell proliferation was measured by counting kit-8 assay. Different assays, including bioinformatics algorithms (TargetScan and miRanda), luciferase report assay and Western blotting, were used to identify the target gene of miR-638 in GC. The expression of miR-638 target gene in clinical CRC tissues was also validated by immunohistochemical assay. From this research, we found that miR-638 was downregulated in GC tissues compared with corresponding noncancerous tissues (NCTs), and the DNA copy number of miR-638 was lower in GC than NCTs, which may induce the corresponding downregulation of miR-638 in GC. Ectopic expression of miR-638 inhibited GC cell growth in vitro. Subsequently, we identified that PLD1 is the target gene of miR-638 in GC, and silencing PLD1 expression phenocopied the inhibitory effect of miR-638 on GC cell proliferation. Furthermore, we observed that PLD1 was overexpressed in GC tissues, and high expression of PLD1 in GC predicted poor overall survival. In summary, we revealed that miR-638 functions as a tumor suppressor in GC through inhibiting PLD1.
3' Untranslated Regions ; genetics ; Apoptosis ; genetics ; Base Sequence ; Cell Line, Tumor ; Cell Proliferation ; genetics ; Down-Regulation ; genetics ; Humans ; MicroRNAs ; genetics ; Phospholipase D ; genetics ; Prognosis ; Stomach Neoplasms ; diagnosis ; enzymology ; genetics ; pathology

Autophagy is a conserved lysosomal self-digestion process used for the breakdown of long-lived proteins and damaged organelles, and it is associated with a number of pathological processes, including cancer. Phospholipase D (PLD) isozymes are dysregulated in various cancers. Recently, we reported that PLD1 is a new regulator of autophagy and is a potential target for cancer therapy. Here, we investigated whether PLD2 is involved in the regulation of autophagy. A PLD2-specific inhibitor and siRNA directed against PLD2 were used to treat HT29 and HCT116 colorectal cancer cells, and both inhibition and genetic knockdown of PLD2 in these cells significantly induced autophagy, as demonstrated by the visualization of light chain 3 (LC3) puncta and autophagic vacuoles as well as by determining the LC3-II protein level. Furthermore, PLD2 inhibition promoted autophagic flux via the canonical Atg5-, Atg7- and AMPK-Ulk1-mediated pathways. Taken together, these results suggest that PLD2 might have a role in autophagy and that its inhibition might provide a new therapeutic basis for targeting autophagy.
Autophagy/*drug effects ; Cell Line, Tumor ; Colorectal Neoplasms/enzymology/*genetics/*therapy ; Genetic Therapy ; HCT116 Cells ; Humans ; Phospholipase D/*antagonists & inhibitors/*genetics/metabolism ; Quinolines/*pharmacology ; *RNA Interference ; RNA, Small Interfering/genetics/pharmacology ; Signal Transduction/drug effects ; Spiro Compounds/*pharmacology

Growth factor-stimulated phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine (PC), generating phosphatidic acid (PA) which may act as a second messenger during cell proliferation and survival. Therefore, PLD is believed to play an important role in tumorigenesis. In this study, a potential mechanism for PLD-mediated tumorigenesis was explored. Ectopic expression of PLD1 or PLD2 in human glioma U87 cells increased the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) protein. PLD-induced HIF-1 activation led to the secretion of vascular endothelial growth factor (VEGF), a HIF-1 target gene involved in tumorigenesis. PLD induction of HIF-1alpha was significantly attenuated by 1-butanol which blocks PA production by PLD, and PA per se was able to elevate HIF-1alpha protein level. Inhibition of mTOR, a PA-responsive kinase, reduced the levels of HIF-1alpha and VEGF in PLD-overexpressed cells. Epidermal growth factor activated PLD and increased the levels of HIF-1alpha and VEGF in U87 cells. A specific PLD inhibitor abolished expression of HIF-1alpha and secretion of VEGF. PLD may utilize HIF-1-VEGF pathway for PLD-mediated tumor cell proliferation and survival.
Cell Line, Tumor ; Epidermal Growth Factor/metabolism ; Gene Expression Regulation, Neoplastic ; Glioma/genetics/*metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics/metabolism ; Phosphatidic Acids/*metabolism ; Phospholipase D/genetics/*metabolism ; *Signal Transduction ; Transfection ; Vascular Endothelial Growth Factor A/*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

Radiation and drug resistance remain the major challenges and causes of mortality in the treatment of locally advanced, recurrent and metastatic breast cancer. Dysregulation of phospholipase D (PLD) has been found in several human cancers and is associated with resistance to anticancer drugs. In the present study, we evaluated the effects of PLD inhibition on cell survival, cell death and DNA damage after exposure to ionizing radiation (IR). Combined IR treatment and PLD inhibition led to an increase in the radiation-induced apoptosis of MDA-MB-231 metastatic breast cancer cells. The selective inhibition of PLD1 and PLD2 led to a significant decrease in the IR-induced colony formation of breast cancer cells. Moreover, PLD inhibition suppressed the radiation-induced activation of extracellular signal-regulated kinase and enhanced the radiation-stimulated phosphorylation of the mitogen-activated protein kinases p38 and c-Jun N-terminal kinase. Furthermore, PLD inhibition, in combination with radiation, was very effective at inducing DNA damage, when compared with radiation alone. Taken together, these results suggest that PLD may be a useful target molecule for the enhancement of the radiotherapy effect.
Breast Neoplasms/*drug therapy/*enzymology/pathology ; Cell Death/drug effects/radiation effects ; Cell Line, Tumor ; Cell Proliferation/drug effects/radiation effects ; DNA Damage ; Enzyme Activation/drug effects/radiation effects ; Enzyme Inhibitors/*pharmacology/*therapeutic use ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Female ; Humans ; JNK Mitogen-Activated Protein Kinases/metabolism ; Phospholipase D/*antagonists & inhibitors/metabolism ; Radiation Tolerance/*drug effects ; Radiation, Ionizing ; p38 Mitogen-Activated Protein Kinases/metabolism