Autotaxin induces lung epithelial cell migration through lysoPLD activity-dependent and -independent pathways

Lung cell migration is a crucial step for re-epithelialization that in turn is essential for remodelling and repair after lung injury. In the present paper we hypothesize that secreted ATX (autotaxin), which exhibits lysoPLD (lysophospholipase D) activity, stimulates lung epithelial cell migration through LPA (lysophosphatidic acid) generation-dependent and -independent pathways. Release of endogenous ATX protein and activity was detected in lung epithelial cell culture medium. ATX with V5 tag overexpressed conditional medium had higher LPA levels compared with control medium and stimulated cell migration through G(αi)-coupled LPA receptors, cytoskeleton rearrangement, phosphorylation of PKC (protein kinase C) δ and cortactin at the leading edge of migrating cells. Inhibition of PKCδ attenuated ATX-V5 overexpressed conditional medium-mediated phosphorylation of cortactin. In addition, a recombinant ATX mutant, lacking lysoPLD activity, or heat-inactived ATX also induced lung epithelial cell migration. Extracelluar ATX bound to the LPA receptor and integrin β4 complex on A549 cell surface. Finally, intratracheal administration of LPS (lipopolysaccharide) into the mouse airway induced ATX release and LPA production in BAL (bronchoalveolar lavage) fluid. These results suggested a significant role for ATX in lung epithelial cell migration and remodelling through its ability to induce LPA production-mediated phosphorylation of PKCδ and cortactin. In addition we also demonstrated association of ATX with the epithelial cell-surface LPA receptor and integrin β4.     

Lysophospholipase D and its role in LPA production

Lysophosphatidic acid (LPA) is an important lipid mediator that binds to G-protein-coupled receptors of the Edg family, inducing proliferation and migration in many cell lines. Much has been learned about pathways involved in LPA signaling, but the pathways responsible for LPA production remain to be fully resolved. Several potential routes have been proposed for LPA production. One involves the sequential actions of phopholipase D (PLD) and phospholipase A(2) (PLA(2)). Another route involves the sequential actions of PLA(2) and lysophospholipase D (lysoPLD). LysoPLD is defined as an enzyme which hydrolyzes lysophospholipids to produce LPA. Two major forms of lysoPLD, microsomal and extracellular forms, have been reported. A microsomal lysoPLD plays an important role in the metabolism of platelet-activating factor (PAF) because of its preference for alkyl-phospholipids. The extracellular form of lysoPLD coexists with its substrate, lysophosphatidylcholine (LPC), in the extracellular compartment. LysoPLDs purified from the extracellular space have recently been shown to be molecularly identical to autotaxin (ATX). ATX, an enzyme previously known to possess 5'-nucleotide pyrophosphatase and phosphodiesterase (PDE) activities, was subsequently shown to have lysoPLD activity. The unexpected linkage of the extracellular lysoPLD with ATX has raised many interesting questions. The characterization and purification of lysoPLDs are reviewed here.     

Contribution of phospholipase D in endothelin-1-mediated extracellular signal-regulated kinase activation and proliferation in rat uterine leiomyoma cells

Endothelin (ET)-1 is a mitogenic factor in numerous cell types, including rat myometrial cells. In the present study, we investigated the potential role of ET-1 in the proliferation of tumoral uterine smooth muscle cells (ELT-3 cells). We found that ET-1 exerted a more potent mitogenic effect in ELT-3 cells than in normal myometrial cells, as indicated by the increase in [3H]thymidine incorporation, cell number, and bromodeoxyuridine incorporation. The ET-1 was more efficient than platelet-derived growth factor and epidermal growth factor to stimulate proliferation. The ET-1-mediated cell proliferation was inhibited in the presence of U0126, a specific inhibitor of (mitogen-activated protein kinase ERK kinase), indicating that extracellular signal-regulated kinase (ERK) activation is involved. Additionally, ET-1 induced the activation of phospholipase (PL) D, leading to the synthesis of phosphatidic acid (PA). The ET-1-induced activation of PLD was twofold higher in ELT-3 cells compared to that in normal cells. The two cell types expressed mRNA for PLD1a and PLD2, whereas PLD1b was expressed only in ELT-3 cells. The exposure of cells to butan-1-ol reduced ET-1-mediated production of PA by PLD and partially inhibited ERK activation and DNA synthesis. Addition of exogenous PLD or PA in the medium reproduced the effect of ET-1 on ERK activation and cell proliferation. Collectively, these data indicate that ET-1 is a potent mitogenic factor in ELT-3 cells via a signaling pathway involving a PLD-dependent activation of ERK. This highlights the potential role of ET-1 in the development of uterine leiomyoma, and it reinforces the role of PLD in tumor growth.     

Enhancement of lysophosphatidic acid-induced ERK phosphorylation by phospholipase D1 via the formation of phosphatidic acid

We made stable cell lines overexpressing PLD1 (GP-PLD1) from GP+envAm12 cell, a derivative of NIH 3T3 cell. PLD1 activity and extracellular signal-regulated kinase (ERK) phosphorylation were enhanced in GP-PLD1 cells by the treatment of lysophosphatidic acid (LPA). In contrast, these LPA-induced effects were attenuated with the pretreatment of pertussis toxin (PTX) or protein kinase C (PKC) inhibitor. Moreover, accumulation of phosphatidic acid (PA), a product of PLD action, potentiated the LPA-induced ERK activation in GP-PLD1 cells while blocking of PA production with the treatment of 1-butanol attenuated LPA-induced ERK phosphorylation. From these results, we suggest that LPA activate PLD1 through pertussis toxin-sensitive G protein and PKC-dependent pathways, then PA produced from PLD1 activation facilitate ERK phosphorylation.     

Regulation of lysophosphatidate signaling by autotaxin and lipid phosphate phosphatases with respect to tumor progression, angiogenesis, metastasis and chemo-resistance

Evidence from clinical, animal and cell culture studies demonstrates that increased autotaxin (ATX) expression is responsible for enhancing tumor progression, cell migration, metastases, angiogenesis and chemo-resistance. These effects depend mainly on the rapid formation of lysophosphatidate (LPA) by ATX. Circulating LPA has a half-life of about 3 min in mice and it is degraded by the ecto-activities of lipid phosphate phosphatases (LPPs). These enzymes also hydrolyze extracellular sphingosine 1-phosphate (S1P), a potent signal for cell division, survival and angiogenesis. Many aggressive tumor cells express high ATX levels and low LPP activities. This favors the formation of locally high LPA and S1P concentrations. Furthermore, LPPs attenuate signaling downstream of the activation of G-protein coupled receptors and receptor tyrosine kinases. Therefore, we propose that the low expression of LPPs in many tumor cells makes them hypersensitive to growth promoting and survival signals that are provided by LPA, S1P, platelet-derived growth factor (PDGF) and epidermal growth factor (EGF). One of the key signaling pathways in this respect appears to be activation of phospholipase D (PLD) and phosphatidate (PA) production. This is required for the transactivations of the EGFR and PDGFR and also for LPA-induced cell migration. PA also increases the activities of ERK, mTOR, myc and sphingosine kinase-1 (SK-1), which provide individual signals for cells division, survival, chemo-resistance and angiogenesis. This review focuses on the balance of signaling by bioactive lipids including LPA, phosphatidylinositol 3,4,5-trisphosphate, PA and S1P versus the action of ceramides. We will discuss how these lipid mediators interact to produce an aggressive neoplastic phenotype.     

Mechanisms of lysophosphatidic acid production

Lysophosphatidic acid is one of the most attractive phospholipid mediator with multiple biological functions and is implicated in various human diseases. In the past ten years much has been learned about the physiological roles of LPA through series of studies on LPA actions and its receptors. However, the molecular mechanisms of LPA have been poorly understood. LPA is produced in various conditions both in cells and in biological fluids, where multiple synthetic reactions occur. At least two pathways are postulated. In serum and plasma, LPA is mainly converted from lysophospholipids. By contrast, in platelets and some cancer cells, LPA is converted from phosphatidic acid. In each pathway, at least two phospholipase activities are required: phospholipase A1 (PLA1)/PLA2 plus lysophospholipase D (lysoPLD) activities are involved in the first pathway and phospholipase D (PLD) plus PLA1/PLA2 activities are involved in the second pathway. Now multiple phospholipases are identified that account for PLA1, PLA2, PLD, and lysoPLD activities. In the absence of specific inhibitors and genetically modified animals and individuals, the contribution of each phospholipase to LPA production can not be easily determined. However, apparently certain extracellular phospholipases such as secretory PLA2 (sPLA2-IIA), membrane-associated PA-selective PLA1 (mPA-PLA1), lecithin-cholesterol acyltransferase (LCAT), and lysoPLD are involved in LPA production.     

The endothelin axis in uterine leiomyomas: new insights

The endothelin axis, comprising endothelin-1 (ET-1) and its receptors (ETA and ETB), is involved in the pathophysiology of different human tumors. Here we review conventional approaches and gene expression profiling indicating the association of ET-1 and its cognate receptors with human and rat leiomyomas, the most common benign tumors of myometrium. Specifically, ET-1/ETA interactions affect human and rat leiomyoma cell proliferation through protein kinase C and mitogen-activated protein kinase-dependent signaling pathways. Recent experiments demonstrate that the ET-1 axis exerts a potent antiapoptotic effect involving sphingolipid metabolism and prostaglandin-endoperoxide synthase 2/prostaglandin system in the rat Eker leiomyoma tumor-derived ELT3 cell line. Evidence supports that steroid hormones, growth factors, and extracellular matrix are key regulators of the leiomyoma growth. Interestingly, the ET-1 axis is under steroid hormones and can cooperate with these growth factors. Therefore, ET-1 alone or in association with these factors could contribute to the complex regulation of uterine tumor growth, such as proliferation, survival, and extracellular matrix production. This review summarizes current knowledge and emerging data on ET-1 in uterine leiomyoma pathology.     

Phosphatase-resistant analogues of lysophosphatidic acid: agonists promote healing, antagonists and autotaxin inhibitors treat cancer

Isoform-selective agonists and antagonists of the lysophosphatidic acid (LPA) G protein-coupled receptors (GPCRs) have important potential applications in cell biology and therapy. LPA GPCRs regulate cancer cell proliferation, invasion, angiogenesis, and also biochemical resistance to chemotherapy- and radiotherapy-induced apoptosis. LPA and its analogues also are feedback inhibitors of the enzyme lysophospholipase D (lysoPLD, a.k.a., autotaxin, ATX), a central regulator of invasion and metastasis. For cancer therapy, the optimal therapeutic profile would be a metabolically-stabilized, pan-LPA receptor antagonist that also inhibited lysoPLD. For protection of gastrointestinal mucosa and lymphocytes, LPA agonists would be desirable to minimize or reverse radiation or chemical-induced injury. Analogues of lysophosphatidic acid (LPA) that are chemically modified to be less susceptible to phospholipases and phosphatases show activity as long-lived receptor-specific agonists and antagonists for LPA receptors, as well as inhibitors for the lysoPLD activity of ATX.     

Thematic Review Series: Lysophospholipids and their Receptors: Autotaxin: structure-function and signaling

Autotaxin (ATX), or ecto-nucleotide pyrophosphatase/phosphodiesterase-2, is a secreted lysophospholipase D (lysoPLD) that hydrolyzes extracellular lysophospholipids into the lipid mediator lysophosphatidic acid (LPA), a ligand for specific G protein-coupled receptors. ATX-LPA signaling is essential for development and has been implicated in a great diversity of (patho)physiological processes, ranging from lymphocyte homing to tumor progression. Structural and functional studies have revealed what makes ATX a unique lysoPLD, and how secreted ATX binds to its target cells. The ATX catalytic domain shows a characteristic bimetallic active site followed by a shallow binding groove that can accommodate nucleotides as well as the glycerol moiety of lysophospholipids, and by a deep lipid-binding pocket. In addition, the catalytic domain has an open tunnel of unknown function adjacent to the active site. Here, we discuss our current understanding of ATX structure-function relationships and signaling mechanisms, and how ATX isoforms use distinct mechanisms to target LPA production to the plasma membrane, notably binding to integrins and heparan sulfate proteoglycans. We also briefly discuss the development of drug-like inhibitors of ATX.     

Autotaxin and lysophosphatidic acid stimulate intestinal cell motility by redistribution of the actin modifying protein villin to the developing lamellipodia

Autotaxin (ATX) is a potent tumor cell motogen that can produce lysophosphatidic acid (LPA) from lysophosphatidylcholine. LPA is a lipid mediator that has also been shown to modulate tumor cell invasion. Autotaxin mRNA is expressed at significant levels in the intestine. Likewise, LPA2 receptor levels have been shown to be elevated in colon cancers. The molecular mechanism of ATX/LPA-induced increase in intestinal cell migration however, remains poorly understood. Villin is an intestinal and renal epithelial cell specific actin regulatory protein that modifies epithelial cell migration. In this study we demonstrate that both Caco-2 (endogenous villin) and MDCK (exogenous villin) cells, which express primarily LPA2 receptors, show enhanced cell migration in response to ATX/LPA. ATX and LPA treatment results in the rapid formation of lamellipodia and redistribution of villin to these cell surface structures, suggesting a role for villin in regulating this initial event of cell locomotion. The LPA-induced increase in cell migration required activation of c-src kinase and downstream tyrosine phosphorylation of villin by c-src kinase. LPA stimulated cell motility was determined to be insensitive to pertussis toxin, but was regulated by activation of PLC-gamma 1. Together, our results show that in epithelial cells ATX and LPA act as strong stimulators of cell migration by recruiting PLC-gamma 1 and villin, both of which participate in the initiation of protrusion.     

Autotaxin has lysophospholipase D activity leading to tumor cell growth and motility by lysophosphatidic acid production

Autotaxin (ATX) is a tumor cell motility-stimulating factor, originally isolated from melanoma cell supernatants. ATX had been proposed to mediate its effects through 5'-nucleotide pyrophosphatase and phosphodiesterase activities. However, the ATX substrate mediating the increase in cellular motility remains to be identified. Here, we demonstrated that lysophospholipase D (lysoPLD) purified from fetal bovine serum, which catalyzes the production of the bioactive phospholipid mediator, lysophosphatidic acid (LPA), from lysophosphatidylcholine (LPC), is identical to ATX. The Km value of ATX for LPC was 25-fold lower than that for the synthetic nucleoside substrate, p-nitrophenyl-tri-monophosphate. LPA mediates multiple biological functions including cytoskeletal reorganization, chemotaxis, and cell growth through activation of specific G protein-coupled receptors. Recombinant ATX, particularly in the presence of LPC, dramatically increased chemotaxis and proliferation of multiple different cell lines. Moreover, we demonstrate that several cancer cell lines release significant amounts of LPC, a substrate for ATX, into the culture medium. The demonstration that ATX and lysoPLD are identical suggests that autocrine or paracrine production of LPA contributes to tumor cell motility, survival, and proliferation. It also provides potential novel targets for therapy of pathophysiological states including cancer.     

Altered activation of phospholipase D by lysophosphatidic acid and endothelin-1 in mouse embryo fibroblasts lacking phospholipase C-gamma1

Lysophosphatidic acid (LPA) and endothelin-1 (ET-1) activate phospholipase D (PLD) in many cell types. To see if phospholipase C-gamma1 plays a role, we used embryonic fibroblasts from mice in which the PLCgamma1 gene was disrupted. Surprisingly, the effect of LPA on inositol phosphate accumulation was increased in these PLCgamma1-/- cells, whereas that of ET-1 was completely abrogated. When PLD activity was measured, the response to LPA was also enhanced and the response to ET-1 lost in the PLCgamma1-/- cells. Treatment of these cells with ionomycin and oleoyl acetyl glycerol to mimic PLC stimulation restored PLD activity. Treatment of either PLCgamma1+/+ and PLCgamma1-/- cells with tyrosine kinase inhibitors did not inhibit LPA- or ET-1-induced PLD activity. Moreover, LPA and ET-1 treatment of PLCgamma1+/+ and PLCgamma1-/- cells did not cause tyrosine phosphorylation of PLC-gamma1 or PLC-gamma2. In summary, these results show that the altered PLD responses to LPA and ET-1 in PLCgamma1-/- are due to changes in PLC activity and do not involve tyrosine kinase activity.     

Lysophosphatidic acid and autotaxin stimulate cell motility of neoplastic and non-neoplastic cells through LPA1

Autotaxin (ATX) is a tumor cell motility-stimulating factor originally isolated from melanoma cell supernatant that has been implicated in regulation of invasive and metastatic properties of cancer cells. Recently, we showed that ATX is identical to lysophospholipase D, which converts lysophosphatidylcholine to a potent bioactive phospholipid mediator, lysophosphatidic acid (LPA), raising the possibility that autocrine or paracrine production of LPA by ATX contributes to tumor cell motility. Here we demonstrate that LPA and ATX mediate cell motility-stimulating activity through the LPA receptor, LPA(1). In fibroblasts isolated from lpa(1)(-/-) mice, but not from wild-type or lpa(2)(-/-), cell motility stimulated with LPA and ATX was completely absent. In the lpa(1)(-/-) cells, LPA-stimulated lamellipodia formation was markedly diminished with a concomitant decrease in Rac1 activation. LPA stimulated the motility of multiple human cancer cell lines expressing LPA(1), and the motility was attenuated by an LPA(1)-selective antagonist, Ki16425. The present study suggests that ATX and LPA(1) represent potential targets for cancer therapy.     

Production of bioactive lysophosphatidic acid by lysophospholipase D in hen egg white

Lysophosphatidic acid (LPA), a lysophospholipid mediator, is produced extracellularly by lysophospholipase D (lysoPLD) secreted in several animal body fluids including blood plasma. Previously, we reported that hen egg white contains polyunsaturated fatty acid-rich LPA. In this study, we examined whether lysoPLD is involved in the production of LPA in hen egg white. LysoPLD activity was measured by determining LPA and choline by mass spectrometric and enzyme-linked fluorometric analyses, respectively. LysoPLD increased with increased dilution of egg white, indicating that one or more components of egg white strongly inhibit its lysoPLD activity. This dilution-dependent increase in the lysoPLD activity was masked by co-incubation of the egg white with lysozyme, a major protein in hen egg white. Furthermore, addition of Zn(2+), Mn(2+), Ni(2+), or Co(2+) to diluted egg white altered preference patterns of lysoPLD toward choline-containing substrates. In particular, the egg white lysoPLD activity was greatly increased when Co(2+) was added. The cation-requirement of lysoPLD activity in hen egg white resembled that of plasma autotaxin (ATX)/lysoPLD. Western blot analysis revealed that egg white contained a protein that was immunostained with anti-ATX antibody. These results suggested that LPA in hen egg white is produced from lysophospholipids, especially LPC, by the action of ATX/lysoPLD, possibly originating from hen oviduct fluid.     

Phospholipase D stimulation is required for sphingosine-1-phosphate activation of actin stress fibre assembly in human airway epithelial cells.

In human airway epithelial cells, sphingosine-1-phosphate (SPP) and lysophosphatidic acid (LPA) stimulated the production of phosphatidic acid (PA), which was inhibited by the primary alcohol butan-1-ol, but not by the inactive butan-2-ol, clearly indicating phospholipase D (PLD) involvement. Both SPP and LPA stimulated actin stress fibre formation, which was also butan-2-ol-insensitive and inhibited by butan-1-ol. SPP-induced PLD activation and cytoskeletal remodelling were insensitive to brefeldin A and toxin B from Clostridium difficile, which conversely blocked the effect of LPA, suggesting that the monomeric GTPases ADP ribosylation factor (ARF) and Rho are involved in LPA, but not in SPP responses. Pertussis toxin inhibited SPP- but not LPA-induced effects. PLD activation and stress fibre formation by both lysolipids were abolished by the tyrosine kinase inhibitor genistein. Addition of PA to cells caused a massive stress fibre assembly. In conclusion, PLD is one of the signalling components linking SPP-receptor activation to assembly of actin stress fibres.     

Endothelin Stimulates Phospholipase D in Striatal Astrocytes

Abstract: In primary cultures of mouse striatal astrocytes prelabeled with [³H]myristic acid, endothelin (ET)-1 induced a time-dependent formation of [³H]phosphatidic acid and [³H]diacylglycerol. In the presence of ethanol, a production of [³H]phosphatidylethanol was observed, indicating the activation of a phospholipase D (PLD). ET-1 and ET-3 were equipotent in stimulating PLD activity (EC₅₀ = 2–5 n M ). Pretreatment of the cells with pertussis toxin partially abolished the effect of ET-1, indicating the involvement of a G_i/G_o protein. Inhibition of protein kinase C by Ro 31-8220 or down-regulation of the kinase by a long-time treatment with phorbol 12-myristate 13-acetate (PMA) totally abolished the ET-1-induced stimulation of PLD. In contrast, a cyclic AMP-dependent process is not involved in the activation of PLD, because the ET-1-evoked formation of [³H]phosphatidylethanol was not affected when cells were coincubated with either isoproterenol, 8-bromo-cyclic AMP, or forskolin. Acute treatment with PMA also stimulated PLD through a protein kinase C-dependent process. However, the ET-1 and PMA responses were additive. Furthermore, the ET-1-evoked response, contrary to that of PMA, totally depended on the presence of extracellular calcium. These results suggest that at least two distinct mechanisms are involved in the control of PLD activity in striatal astrocytes. Finally, ET-1, ET-3, and PMA also stimulated PLD in astrocytes from the mesencephalon, the cerebral cortex, and the hippocampus.     

Synthesis and pharmacological evaluation of second-generation phosphatidic acid derivatives as lysophosphatidic acid receptor ligands

Short-chain phosphatidic acid derivatives, dioctanoyl glycerol pyrophosphate (DGPP 8:0, 1) and phosphatidic acid 8:0 (PA 8:0, 2), were previously identified as subtype-selective LPA(1) and LPA(3) receptor antagonists. Recently, we reported that the replacement of the phosphate headgroup by thiophosphate in a series of fatty alcohol phosphates (FAP) improves agonist as well as antagonist activities at LPA GPCR. Here, we report the synthesis of stereoisomers of PA 8:0 analogs and their biological evaluation at LPA GPCR, PPARgamma, and ATX. The results indicate that LPA receptors stereoselectively interact with glycerol backbone modified ligands. We observed entirely stereospecific responses by dioctyl PA 8:0 compounds, in which (R)-isomers were found to be agonists and (S)-isomers were antagonists of LPA GPCR. From this series, we identified compound 13b as the most potent LPA(3) receptor subtype-selective agonist (EC(50)=3 nM), and 8b as a potent and selective LPA(3) receptor antagonist (K(i)=5 nM) and inhibitor of ATX (IC(50)=600 nM). Serinediamide phosphate 19b was identified as an LPA(3) receptor specific antagonist with no effect on LPA(1), LPA(2), and PPARgamma.     

Endothelin-1 activates phospholipase D and thymidine incorporation in fibroblasts overexpressing protein kinase C beta 1.

Endothelins (ETs) are a family of extremely potent vasoconstrictor peptides. In addition, ET-1 acts as a potent mitogen and activates phospholipase C in smooth muscle cells and fibroblasts. We examined the effects of ET-1 on phosphatidylcholine (PC) metabolism and thymidine incorporation in control Rat-6 fibroblasts and in cells that overexpress protein kinase C beta 1 (PKC). PC pools were labeled with [3H]myristic acid, and formation of phosphatidylethanol (PEt), an unambiguous marker of phospholipase D (PLD) activation, was monitored. ET-1 stimulated much greater PEt formation in the PKC overexpressing cells. ET-1 action was dose-dependent with a half-maximal effect at 1.0 x 10(-9) M. With increasing ethanol concentrations, [3H]PEt formation increased at the expense of [3H]phosphatidic acid (PA). Propranolol, an inhibitor of PA phosphohydrolase, increased [3H]PA accumulation and decreased [3H]diacylglycerol (DAG) formation. These data are consistent with the formation of [3H]DAG from PC by the sequential action of PLD and PA phosphohydrolase. Phorbol esters are known to stimulate thymidine incorporation and PLD activity to a greater extent in PKC overexpressing cells than in control cells. ET-1 also stimulates thymidine incorporation to a greater extent in the PKC overexpressing cells. The effect of ET-1 on thymidine incorporation into DNA in the overexpressing cells was also dose-dependent with a half-maximal effect at 0.3 x 10(-9) M. Enhanced PLD activity induced by ET-1 in the overexpressing cells may contribute to the mitogenic response, especially in light of a possible role of the PLD product, PA, in regulation of cell growth.     

自分泌运动因子-溶血磷脂酸轴的生物学功能与调控

自分泌运动因子(autotaxin,ATX)也称作磷酸二酯酶Iα,是核苷酸焦磷酸酶/磷酸二酯酶家族(nucleotide pyrophosphatases,NPPs)中的一员,因而也称作NPP2.ATX是NPPs中唯一具有溶血磷脂酶D(lysophospholipase D,lysoPLD)活性的成员,它可以将溶血磷脂...