Phospholipase D regulates ferroptosis signal transduction in mouse spleen hypoxia response

High-altitude hypoxia exposure can lead to phospholipase D-mediated lipid metabolism disorder in spleen tissues and induce ferroptosis. Nonetheless, the key genes underlying hypoxia-induced splenic phospholipase D and the ferroptosis pathway remain unclear. This study aimed to establish a hypoxia animal model. Combined transcriptomic and proteomic analyses showed that 95 predicted target genes (proteins) were significantly differentially expressed under hypoxic conditions. Key genes in phospholipase D and ferroptosis pathways under hypoxic exposure were identified by combining Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis techniques. Gene set enrichment analysis (GSEA) showed that the differential gene sets of the phospholipase D and ferroptosis signaling pathways were upregulated in the high-altitude hypoxia group. The genes in the phospholipase D signalling pathway were verified, and the expression levels of KIT and DGKG were upregulated in spleen tissues under hypoxic exposure. Subsequently, the mRNA and protein expression levels of genes from the exogenous pathway such as TFRC, SLC40A1, SLC7A11, TRP53, and FTH1 and those from the endogenous pathway such as GPX4, HMOX1, and ALOX15 differentials in the ferroptosis signalling pathway were verified, and the results indicated significant differential expression. In summary, exposure to high-altitude hypoxia mediated phospholipid metabolism disturbance through the phospholipase D signalling pathway and further induced ferroptosis, leading to splenic injury.

High-level soluble expression of phospholipase D from Streptomyces chromofuscus in Escherichia coli by combinatorial optimization

BACKGROUND: Phospholipase D (PLD) is used as the biocatalyst for phosphatidylserine (PS) production. In general, PLD was expressed in insoluble form in Escherichia coli. High-level soluble expression of PLD with high activity in E. coli is very important for industrial production of PLD. RESULTS: Streptomyces chromofuscus PLD coding gene was codon-optimized, cloned without signal peptide, and expressed in E. coli. The optimal recombinant E. coli pET-28a+PLD/BL21(DE3) was constructed with pET-28a without His-tag. The highest PLD activity reached 104.28 ± 2.67 U/mL in a 250-mL shake flask after systematical optimization. The highest PLD activity elevated to 122.94 ± 1.49 U/mL by feeding lactose and inducing at 20 C after scaling up to a 5.0-L fermenter. Substituting the mixed carbon source with 1.0 % (w/v) of cheap dextrin and adding a feeding medium could still attain a PLD activity of 105. 81 ± 2.72 U/mL in a 5.0-L fermenter. Fish peptone from the waste of fish processing and dextrin from the starch are both very cheap, which were found to benefit the soluble PLD expression. CONCLUSIONS: After combinatorial optimization, the high-level soluble expression of PLD was fulfilled in E. coli. The high PLD activity along with cheap medium obtained at the fermenter level can completely meet the requirements of industrial production of PLD.

Identification and functional analysis of a novel phospholipase D2 gene mutation associated with familial systemic lupus erythematosus / 中南大学学报(医学版)

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.

Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (440 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.

Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (4-40 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.(AU)

Research advances on the virulence factors of Corynebacterium pseudotuberculosis / 中国人兽共患病学报

Zoonotic pathogen Corynebacterium pseudotuberculosis is the etiological agent of Caseous lymphadenitis (CLA),a chronic infectious disease throughout almost the whole world,which is extremely difficult to control.The pathogenesis of C.pseudotuberculosis is closely related to its virulence factors.In this paper,the virulence factors of C.pseudotuberculosis are reviewed,and it is proposed to further identify and analyze the roles and correlations of other different virulence factors in the pathogenesis of C.pseudotuberculosis infection,which is important for understanding the pathogenic mechanism and identify candidate vaccine of C.pseudotuberculosis.

The influence of silencing of NF-κB gene on the proliferation of gastric cancer cells exposed to hypoxia and its mechanism / 肿瘤

Objective: To investigate the influence of nuclear factor-κB (NF-κB) gene silence on the proliferation of gastric cancer SGC-7901 cells exposed to hypoxia and its possible mechanism. Methods: SGC-7901 cells were transfected with recombinant vector pcDNA™ 6.2-GW/EmGFPmiR-NF-κB in which the NF-κB was silenced, and the stably transfected cell line SGC-7901 was screened out. There are four groups were designed in this study: control group (SGC-7901 cells were cultured under normoxic conditions), hypoxic group (SGC-7901 cells were cultured under hypoxic conditions), transfection group (SGC-7901 cells were transfected with recombinant vector pcDNA™ 6.2-GW/EmGFPmiR-NF-κB and cultured under normoxic conditions) and combination group (SGC-7901 cells were transfected with recombinant vector pcDNA™6.2-GW/EmGFPmiR-NF-κB and cultured under hypoxic conditions). The viability of SGC-7901 cells in each group was detected by Trypan blue staining. The colony-formation assay and cell doubling time assay were used to examine the proliferation of SGC-7901 cells. The expression levels of NF-κB, hypoxia-inducible factor-1α (HIF-1α) and phospholipase D1 (PLD1) proteins in SGC-7901 cells were examined by Western blotting. Results: The SGC-7901 cells were successfully transfected with recombinant vector pcDNA™6.2-GW/EmGFPmiR-NF-κB, and the stably transfected cell line was established. As compared with the control group, the viabilities of SGC-7901 cells in the transfection group and the combination group were obviously decreased (P < 0.05), but there was no significant change in the hypoxic group. As compared with the control group, the colony-forming number of SGC-7901 cells in the hypoxic group was increased and the cell doubling time was shortened (P < 0.05), while the numbers of colony-forming in the transfection group and combination group were decreased and the cell doubling time was prolonged (P < 0.05). The expression levels of NF-κB, HIF-1α and PLD1 proteins in SGC-7901 cells in the transfection group were obviously suppressed, while these expressions in the hypoxic group were obviously up-regulated (P < 0.05). As compared with the hypoxic group, the expression levels of NF-κB, HIF-1α and PLD1 proteins in SGC-7901 cells in the combination group were significanly down-regulated (P < 0.05). Conclusion: In SGC-7901 cells exposed to hypoxic conditions, there may be an interaction between HIF-1α and NF-κB. The suppression of NF-κB expression can inhibit the proliferative ability of gastric cancer SGC-7901 cells under hypoxic conditions via down-regulation of HIF-1α and PLD-1 expressions Copyright© 2014 by TUMOR.

Effects of interference with the expressions of aquaporin 3 and phospholipase D2 by small interfering RNAs on the proliferation and apoptosis of a human cutaneous squamous cell carcinoma cell line A431 / 中华皮肤科杂志

Objective To investigate the effects of aquaporin 3 (AQP3) and phospholipase D2 (PLD2) on the proliferation and apoptosis of a human cutaneous squamous cell carcinoma cell line A431.Methods Three small interfering RNAs (siRNAs) were constructed targeting the AQP3 and PLD2 genes separately,and transfected into A431 cells using liposomes.Then,fluorescence quantitative PCR was performed to find the most efficient siRNAs.Western blot was conducted to detect the protein expression levels of AQP3 and PLD2 in A431 cells after transfection with the selected AQP3-siRNA and PLD2-siRNA.Some A431 cells were divided into five groups:normal control group without any treatment,transfection reagent group treated with the oligofectamine reagent only,negative control group transfected with the negative control siRNA,AQP3-siRNA group transfected with the selected AQP3-siRNA,PLD2-siRNA group transfected with the selected PLD2-siRNA.After additional culture,cell counting kit-8 assay was performed to evaluate the proliferation of A431 cells,flow cytometry to detect the apoptosis of A431 cells after annexin V-fluorescein isocyanate/propidium iodide double-staining.Statistical analysis was carried out by the paired t test.Results The transfection with AQP3-siRNA and PLD2-siRNA induced a significant decrease in the mRNA and protein expressions of AQP3 and PLD2 respectively in A431 cells when compared with the untransfected cells.Compared with the negative control group,the proliferation of A431 cells was significantly decelerated at 24,48 and 72 hours after transfection in the AQP3-siRNA group (t =24.10,11.00,9.54,respectively,all P ＜ 0.01) and PLD2-siRNA group (t =30.47,7.02,8.73,respectively,all P ＜ 0.01).A significant increase was observed in the apoptosis of A431 cells at 48 and 72 hours after transfection with AQP3-siRNA (t =11.36,20.91,respectively,both P ＜ 0.01),and at 72 hours after transfection with PLD2-siRNA (t =4.86,P ＜ 0.05) compared with the negative control group.Conclusion The down-regulation of AQP3 and PLD2 expressions by siRNA can inhibit the proliferation,but induce the apoptosis,of A431 cells.

Progress in reguIation of phosphoIipase D mediated by Wnt/β-catenin and NF-κB signaIing pathways and its reIationships with tumorigenesis / 中国药理学与毒理学杂志

Over the last few years,elevated phospholipase D(PLD)expression and activity found to be mediated by Wnt/ β-catenin and NF-κB signaling axis sharing the same downstream genes have been involved in tumorigenesis,controlling cancer cell invasion and metastasis. New studies have revealed that Wnt signaling/ NF-κB signaling can induce PLD upregulation and increased enzymatic activ-ity. PLD/ PLD-generated phosphatidic acid( PA),as a critical regulator,might positively modulate β-catenin-dependent T-cell factor and NF-κB transcriptional activity via a targeted motif and a positive feed-back loop to reinforce pathway output including cyclin D1 ,c-myc,survivin,vascular endothelial growth factor and cyclooxygenase-2,while PLD/ PA inhibitors can reverse all the effect mentioned above and achieve significantly better anticancer effects. The PLD/ PA signaling pathway can be a novel therapeutic target for the treatment of cancer.

Phospholipase D inhibitor enhances radiosensitivity of breast cancer cells

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.

The hydrophobic amino acids involved in the interdomain association of phospholipase D1 regulate the shuttling of phospholipase D1 from vesicular organelles into the nucleus

Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to generate the lipid second messenger, phosphatidic acid. PLD is localized in most cellular organelles, where it is likely to play different roles in signal transduction. PLD1 is primarily localized in vesicular structures such as endosomes, lysosomes and autophagosomes. However, the factors defining its localization are less clear. In this study, we found that four hydrophobic residues present in the N-terminal HKD catalytic motif of PLD1, which is involved in intramolecular association, are responsible for vesicular localization. Site-directed mutagenesis of the residues dramatically disrupted vesicular localization of PLD1. Interestingly, the hydrophobic residues of PLD1 are also involved in the interruption of its nuclear localization. Mutation of the residues increased the association of PLD1 with importin-beta, which is known to mediate nuclear importation, and induced the localization of PLD1 from vesicles into the nucleus. Taken together, these data suggest that the hydrophobic amino acids involved in the interdomain association of PLD1 are required for vesicular localization and disturbance of its nuclear localization.

A simple technique for estimation of phospholipase d and phospholipase c enzymes in smooth muscle and its cells.

This research article describes two novel and simple techniques for the estimation of phospholipase D and phospholipase C enzymes in aortic smooth muscle and cells cultured from the bovine aorta. The techniques encompass the use of ion exchange chromatography and liquid scintillation spectrophotometry.

Phospholipase Activities in Clinical and Environmental Isolates of Acanthamoeba

The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phos-pholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase A2 (PLA2) and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA2. Acanthamoeba exhibited optimal phospholipase activities at 37degrees C and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA2-specific inhibitor, i.e., cytidine 5'-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.

Effect of Extremely Low Frequency Electromagnetic Fields (EMF) on Phospholipase Activity in the Cultured Cells

This study was conducted to investigate the effects of extremely low frequency electromagnetic fields (EMF) on signal pathway in plasma membrane of cultured cells (RAW 264.7 cells and RBL 2H3 cells), by measuring the activity of phospholipase A2 (PLA2), phospholipase C (PLC) and phospholipase D (PLD). The cells were exposed to the EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h. The basal and 0.5 microM melittin-induced arachidonic acid release was not affected by EMF in both cells. In cell-free PLA2 assay, we failed to observe the change of cPLA2 and sPLA2 activity. Also both PLC and PLD activities did not show any change in the two cell lines exposed to EMF. This study suggests that the exposure condition of EMF (60 Hz, 0.1 or 1 mT) which is 2.4 fold higher than the limit of occupational exposure does not induce phospholipases-associated signal pathway in RAW 264.7 cells and RBL 2H3 cells.

Role of phospholipase D1 in glucose-induced insulin secretion in pancreatic beta cells

As glucose is known to induce insulin secretion in pancreatic beta cells, this study investigated the role of a phospholipase D (PLD)-related signaling pathway in insulin secretion caused by high glucose in the pancreatic beta-cell line MIN6N8. It was found that the PLD activity and PLD1 expression were both increased by high glucose (33.3 mM) treatment. The dominant negative PLD1 inhibited glucose-induced Beta2 expression, and glucose-induced insulin secretion was blocked by treatment with 1-butanol or PLD1-siRNA. These results suggest that high glucose increased insulin secretion through a PLD1-related pathway. High glucose induced the binding of Arf6 to PLD1. Pretreatment with brefeldin A (BFA), an Arf inhibitor, decreased the PLD activity as well as the insulin secretion. Furthermore, BFA blocked the glucose-induced mTOR and p70S6K activation, while mTOR inhibition with rapamycin attenuated the glucose induced Beta2 expression and insulin secretion. Thus, when taken together, PLD1 would appear to be an important regulator of glucose-induced insulin secretion through an Arf6/PLD1/mTOR/p70S6K/Beta2 pathway in MIN6N8 cells.

Rebamipide-induced downregulation of phospholipase D inhibits inflammation and proliferation in gastric cancer cells

Rebamipide a gastroprotective drug, is clinically used for the treatment of gastric ulcers and gastritis, but its actions on gastric cancer are not clearly understood. Phospholipase D (PLD) is overexpressed in various types of cancer tissues and has been implicated as a critical factor in inflammation and carcinogenesis. However, whether rebamipide is involved in the regulation of PLD in gastric cancer cells is not known. In this study, we showed that rebamipide significantly suppressed the expression of both PLD1 and PLD2 at a transcriptional level in AGS and MKN-1 gastric cancer cells. Downregulation of PLD expression by rebamipide inhibited its enzymatic activity. In addition, rebamipide inhibited the transactivation of nuclear factor kappa B (NFkappaB), which increased PLD1 expression. Rebamipide or PLD knockdown significantly suppressed the expression of genes involved in inflammation and proliferation and inhibited the proliferation of gastric cancer cells. In conclusion, rebamipide-induced downregulation of PLD may contribute to the inhibition of inflammation and proliferation in gastric cancer.

Triptolide-induced suppression of phospholipase D expression inhibits proliferation of MDA-MB-231 breast cancer cells

In spite of the importance of phospholipase D (PLD) in cell proliferation and tumorigenesis, little is known about the molecules regulating PLD expression. Thus, identification of small molecules inhibiting PLD expression would be an important advance for PLD-mediated physiology. We examined one such here, denoted "Triptolide", which was identified in a chemical screen for inhibitors of PLD expression using cell assay system based on measurement of PLD promoter activity. Triptolide significantly suppressed the expression of both PLD1 and PLD2 with sub-microM potency in MDA-MB-231 breast cancer cells as analyzed by promoter assay and RT-PCR. Moreover, triptolide abolished the protein level of PLD in a time and dose-dependent manner. Triptolide-induced PLD1 downregulation was also observed in all the cancer cells examined, suggesting a general phenomenon detected in various cancer cells. Decrease of PLD expression by triptolide suppressed both basal and PMA-induced PLD activity. In addition, triptolide inhibited activation of NFkappaB which increased PLD1 expression. Ultimately, downregulation of PLD by triptolide inhibited proliferation of breast cancer cells. Taken together, we demonstrate that triptolide suppresses the expression of PLD via inhibition of NFkappaB activation and then decreases cell proliferation.

A description of genes of Corynebacterium pseudotuberculosis useful in diagnostics and vaccine applications

Corynebacterium pseudotuberculosis, a Gram-positive intracellular pathogen, is the etiological agent of caseous lymphadenitis or CLA. This bacterium infects goats and sheep and causes great economic losses worldwide annually, mainly for goat producers. Despite its importance, CLA is still poorly characterized. However, with advances in the genomic field, many C. pseudotuberculosis genes have already been characterized, mainly those related to virulence such as phospholipase D. Here, we examined the use of the several available genes of C. pseudotuberculosis and reviewed their applications in vaccine construction, more efficient diagnostics for CLA, and control of this disease, among other applications.

Phospholipase D and Pathogenic Microorganisms Invasion / 微生物学通报

Phospholipase D(PLD) is ubiquitous in bacteria,fungi,and mammal.In pathogenic microorganisms,PLD can be pathogenic determinant and play a role in spore generation.In mammalian cells,PLD functions in several signal transduction pathways,such as membrane transportation,mitosis regulation,and actin cytoskeleton regulation.In the process of pathogens invasion host cells,both of the pathogen and host cells’ PLD will be activated and a series of cascade reaction will be generated.During this process,pathogen’s PLD can regulate the polymerization and reorganization of its own actin filaments and induce the polymerization or reorganization of the host cell actin filaments near the foci,thus to promote the phagocytosis of the pathogen by host cell.Investigating the role of PLD activation in the infection will be significance for further understanding the molecular mechanism of pathogen-host cell interaction.

Expresson of the N-terminus truncated phosphotase D in Escherichia coli and characterization of its anti inflammatory activity / 中国人兽共患病学报

To investigate the immunological activities of the recombinant human phosphatase D2 (rhPLD2) in vitro and in vivo, especially its ability to reduce inflammatory reactions, the cDNA fragment encoding rhPLD2 was cloned into prokaryotic expression vector pET30a by RT-PCR and the recombinant protein rhPLD2 expressed in E.coli was purified from the inclusion bodies, while the anti inflammatory activity of rhPLD2 was determined by the amount of eosinophils in bronchoalveolar fluid(BALF) and blood and the expression of IL-5 and MMP-9 in lung tissues of guinea pig model of chronic asthma. It was found that the rhPLD2 recombinant protein was obtained from human Daudi cells by cloning to E.coli, which contained no membrane-binding site and signal peptide. The cDNA sequence encoded 631 amino acid residues (GenBank Accession Number: AY178289). The purity of the rhPLD2 approached up to 76% with a bioactivity of 50.9745 units/L (0.9212 g/L). In addition, the anti inflammatory effect of rhPLD2 protein could be demonstrated in the guinea pig model of chronic asthma after treatment with rhPLD2 protein, such as down regulation in the expression of the inflammatory cytokine IL-5. It is concluded that the anti-inflammator activity of the recombinant human truncated PLD2 protein produced from the E.coli plasmid can be demonstrated both in vitro and in vivo.