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@#Modulating drug release from liposomes at tumor sites are important for eliciting therapeutic effects of platinum drugs considering their low permeability through liposomal membranes, here a novel secretory phospholipase A2 (sPLA2) responsive-liposome system was constructed for oxaliplatin (L-OHP).Lipid ingredients dipalmitoyl phosphatidylcholine and distearoyl phosphoethanolamine-PEG2k, together with facial amphiphiles (FAs) including lithocholic acid (LCA) or 3-keto lithocholic acid (kLCA) were used to prepare sPLA2 responsive-liposome (LCA-Lip or kLCA-Lip) by thin-film hydration method.The physicochemical properties, sPLA2-responsive drug release and anti-tumor activity were evaluated in vitro.The results indicated L-OHP loaded liposomes modified with FAs had similar particle sizes of approximately 100 nm and narrow size distributions (PDI < 0.11).Compared with non-FAs-containing liposomes (C-Lip), LCA-Lip or kLCA-Lip has a comparable entrapment efficiency and loading efficiency.LCA-Lip or kLCA-Lip didn't show significant higher drug leakage at the presence of 10% or 50% fetal bovine serum (FBS) in media than that in media without FBS.Treated with secretory phospholipase A2 from Colo205 cells culture conditioned medium (CCM sPLA2) for 24 h, FAs modified liposomes released about 70% of carboxyfluorescein (CF), while C-Lip only released 20% of CF.Compared to L-OHP loaded C-Lip, L-OHP-loaded FAs-included formulations had much greater anti-proliferative activity against sPLA2-secreting Colo205 cells.In summary, our results shows that LCA or kLCA promotes responsiveness of liposomes to tumor-related sPLA2 and points to a new way to develop platium drugs-loaded liposomal delivery systems with better release mechanisms.
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Objective: To evaluate antioxidant, cytotoxic, and anti-venom capacity of crude bark extracts of Alstonia parvifolia Merr. Methods: Gas chromatography-mass spectrometry (GC-MS) and energy dispersive X-ray analyses were accomplished to characterize the chemical constituents of Alstonia parvifolia. Biochemical characterization was evaluated using an inhibitory phospholipase A 2 (PLA 2) assay, DPPH, and cytotoxicity assays. Using the constituents listed in the GC-MS analyses, molecular docking was conducted to inspect the binding energies between the chosen compounds and selected PLA 2 isoforms. Results: GC-MS analyses showed that the Alstonia parvifolia crude extract consisted predominantly of acetylmarinobufogenin (14.89%), γ-sitosterol (10.44%), 3-O-methyl-D-glucose (5.88%), 3,5-dimethoxy-4-hydroxyphenylacetic acid (5.30%), (2α,5α)-17-methoxyaspidofractinin-3-one (AFM) (4.08%), and 2,3,5,6,7,8,9-heptahydro-1-phenyl-5-(p-chlorophenylimino)-1H-benzo[e] [1],[4] thiazepine (HPT) (1.37%). The principal elemental components of Alstonia parvifolia were Ca (4.012%) and K (1.496%), as exhibited by energy dispersive X-ray examination. Alstonia parvifolia showed significant free radical scavenging ability (IC 50: 0.287 mg/mL) and was non-cytotoxic to normal HDFn cells (IC 50 >100 μg/mL). Moreover, Alstonia parvifolia was favorably cytotoxic to MCF-7 (IC 50: 4.42 μg/mL), followed by H69PR, HT-29, and THP-1, with IC 50 values of 4.94, 5.07, and 6.27 μg/mL, respectively. Alstonia parvifolia also displayed notable inhibition against PLA 2 activity of Naja philippinensis Taylor venom with IC 50 of (15.2 ± 1.8) μg/mL. Docking and cluster analyses projected negative binding energies from AFM (-6.36 to -9.68 kcal/mol), HPT (-7.38 to -9.77 kcal/ mol), and acetylmarinobufogenin (-7.22 to -9.59 kcal/mol). These calculations were for the particular interactions of Alstonia parvifolia constituents to PLA 2 homologues where the utmost affinity was detected in HPT owing to the dipole interactions with amino acid residues. Conclusions: The bark extract of Alstonia parvifolia shows great potential as an anti-venom agent due to its low cytotoxic profile, remarkable PLA 2 inhibition, and docking binding energies between its bioactive constituents and PLA 2 homologues.
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The anti-venom activity of Andrographis paniculata (Burm.f.) Nees roots (APR) dichloromethane crude extractsand a promising APR constituent, skullcapflavone I (SKI) was investigated by monitoring the inhibition of secretoryphospholipase A2 (sPLA2) of Naja philippinensis Taylor venom (NPV) crystallized samples. Gas chromatographymass spectrometry was used for the characterization of extracts, while molecular docking was utilized to understandanti-venom properties. Chromatographic analyses primarily revealed the presence of methoxylated flavones. NPV wasfound to have sPLA2 activity (0.0796 ± 0.0018 μmol/minutes/ml) that has been attributed to the poisonous effects.SKI (IC50: 51.1 ± 3.5 μg/ml), isolated from APR showed strong inhibitory effect on phospholipase activity comparedwith dichloromethane extracts of APR (IC50: 192.7 ± 10.9 μg/ml) indicating that SKI was the cause of the bioactivityin APR. Molecular docking simulations showed corresponding results with highly negative binding energies (−6.59 to−8.72 kcal/mol) predicted for the binding of SKI to PLA2 proteins. An important trend found was the presence of freebound Ca2+ lowered binding energies signifying that Ca2+ a has role in the binding of the SKI to PLA2 proteins. Theanti-venom property of APR and the pure compound SKI, upon further studies, could be the first line of defense in themedical protocol of snake venom neutralization.
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The anti-venom activity of Andrographis paniculata (Burm.f.) Nees roots (APR) dichloromethane crude extractsand a promising APR constituent, skullcapflavone I (SKI) was investigated by monitoring the inhibition of secretoryphospholipase A2 (sPLA2) of Naja philippinensis Taylor venom (NPV) crystallized samples. Gas chromatographymass spectrometry was used for the characterization of extracts, while molecular docking was utilized to understandanti-venom properties. Chromatographic analyses primarily revealed the presence of methoxylated flavones. NPV wasfound to have sPLA2 activity (0.0796 ± 0.0018 μmol/minutes/ml) that has been attributed to the poisonous effects.SKI (IC50: 51.1 ± 3.5 μg/ml), isolated from APR showed strong inhibitory effect on phospholipase activity comparedwith dichloromethane extracts of APR (IC50: 192.7 ± 10.9 μg/ml) indicating that SKI was the cause of the bioactivityin APR. Molecular docking simulations showed corresponding results with highly negative binding energies (−6.59 to−8.72 kcal/mol) predicted for the binding of SKI to PLA2 proteins. An important trend found was the presence of freebound Ca2+ lowered binding energies signifying that Ca2+ a has role in the binding of the SKI to PLA2 proteins. Theanti-venom property of APR and the pure compound SKI, upon further studies, could be the first line of defense in themedical protocol of snake venom neutralization.
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Objective To investigate the relationship between serum secreted phospholipase A2 (sPLA2) and the severity of the disease in cobra bite patients. Methods Fifty-two cobra bite patients admitted to our hospital from January 2015 to December 2015 were selected according to the inclusion and exclusion criteria. According to the degree of disease, patients were divided into the light and heavy risk groups. According to the degree of swelling of the affected limbs, patients were divided into the mild swelling group and moderate-severe swelling group. According to the time difference between visits, patients were divided into: visit time <8 h group and visit time ≥ 8 h group. Twenty healthy adult volunteers served as the control group. The levels of serum sPLA2, C reactive protein (CRP), D-dimer (DD), lactic acid (LAC) and peripheral blood leukocyte count (WBC) were measured and compared in different groups. Quantitative data were analyzed using t test and rank sum test. Results The levels of serum sPLA2 in the light and heavy risk group were statistically different from those in the control group (P<0.05), and were statistically significant between the light and heavy risk groups (P<0.01) and between the mild swelling group and moderate-severe swelling group (P<0.05). The serum sPLA2 levels in group A and group B were also significantly different from those in the control group (P<0.05). The level of sPLA2 was positively correlated with the level of LAC, DD and WBC, and the correlation coefficients were 0.3142, 0.2752 and 0.6534, respectively. Conclusions The higher the level of serum sPLA2, the more serious the patient's poisoning symptoms. It is of certain clinical value to evaluate the condition of cobra.
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Objective To discuss the relationship between the expression of secretory Phospholipase A2-Ⅱ A(sPLA2-ⅡA) and the pathogenesis psoriasis vulgaris patients lesions.Methods Using Psoriasis Area Severity Index(PASI),50 psoriasis vulgaris were divided into three groups:mild (n =16),moderate (n =18) and severe group (n =16),and compared to the non-psoriasis control group (n=52).The serum level of sPLA2-ⅡA in psoriasis vulgaris patients and the normal control group were detected using ELISA methods.Using RT-PCR,mRNA expression levels of sPLA2-ⅡA and subtypes were detected.Using western blot,the expression levels of Akt and p-Akt were detected.Results The serum level of sPLA2-ⅡA in the psoriasis lesion's group was significantly higher than that in the healthy control (t=13.62,P＜0.01).The mRNA expression of sPLA2-ⅡA in the lesion of psoriasis was significantly higher than that in health control (t=113.41,P＜0.01).In the other subtypes,the mRNA expression of sPLA2 had no distinctive.Among the three groups (mild group,moderate group and severe group),the difference in serum level and mRNA expression of sPLA2-ⅡA were statistically significant (F =28.12,69.62,P＜0.01).There was statistical significance among three groups (t=3.14,5.14,6.38,all P＜0.01;t=4.77,10.42,10.58,all P＜0.01).The expression of Akt/p-Akt in the psoriasis lesion's group were higher than that in health control (t=17.79,19.04,P＜0.01).Conclusion The expression of sPLA2-ⅡA would be associated with order of severity in lesions of psoriasis vulgaris.The pathway was relate to expression of Akt and p-Akt.
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Objective To explore the levels of secretory phospholipase A2 (sPLA2) and lysophosphatidic acid (LPA) in blood and cerebrospinal fluid of patients with multiple sclerosis (MS), and to explore the relationship between the levels of these inflammatory biomarkers and disease activity of MS. Methods Blood samples were collected from 21 MS patients of acute period (acute period of MS group), 20 MS patients of remitting period (remitting period of MS group) and 21 patients with non inflammatory and vascular neurologic disease (control group). The levels of sPLA2 and LPA in blood and cerebrospinal fluid were measured and compared. Results The levels of sPLA2 and LPA in blood and cerebrospinal fluid before treatment in acute period of MS group were significantly higher than those in remitting period of MS group (P<0.01) and in control group (P<0.01). The levels of sPLA2 and LPA in blood and cerebrospinal fluid after treatment were significantly lower than those before treatment in acute period of MS group (P<0.01). The levels of sPLA2 and LPA in blood before and after treatment had correlations in acute period of MS group (r=0.962, P=0.000;r=0.848, P=0.000). The levels of sPLA2 and LPA in cerebrospinal fluid before and after treatment had correlations in the acute period group (r=0.968, P=0.000;r=0.850, P=0.000). Conclusions The levels of sPLA2 and LPA in blood and cerebrospinal fluid may be used as inflammatory biomarkers for disease activity in MS patients.
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_ Objective_ To evaluate plasma concentrations of lipoprotein-associated phospholipase A2 (LP-PLA2)andsecretoryphospholipaseA2(sPLA2)inpatientswithnewlydiagnosedtype2diabetes,andtoexplore their clinical significance. Methods Oral glucose tolerance test ( OGTT) was carried out in our hospital to all the subjects without history of diabetes. According to the results of OGTT, they were divided into two groups:patients with newly diagnosed type 2 diabetes and subjects with normal fasting glucose and normal glucose tolerance. Anthropometric data such as height, weight, waist circumference, and blood pressure were measured and concentrations of blood glucose, insulin, lipid profile ( including total cholesterol, triglycerides, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol), LP-PLA2, and sPLA2 were determined in both groups. Results Ninety patients with newly diagnosed type 2 diabetes and fifty-eight subjects with normal glucose tolerance were enrolled in our study. As to gender, age, body mass index, blood pressure, and lipid profile, there were no statistically differences between these two groups (P>0. 05). Plasma levels of LP-PLA2 and sPLA2 in diabetic patients were significantly higher than normoglycemic participants [102. 98(76. 34,134. 31) vs 50. 89(23. 71,90. 40) ng/ml, 219. 33 (130. 03,337. 330) vs 78. 55 (75. 15,87. 02) ng/ml, both P<0. 01]. Plasma concentrations of LP-PLA2 and sPLA2 in diabetic patients with atherosclerosis were significantly higher than those without [ 133. 43 ( 111. 54, 145. 17 ) vs 99. 11 ( 63. 02, 130. 85) ng/ml,235. 73 (180. 48, 416. 46) vs 182. 97 (9. 08, 280. 79) ng/ml, both P<0. 05]. LP-PLA2 and sPLA2 were both positively correlated with homeostasis model assessment for insulin resistance (HOMA-IR), while negatively correlated with insulin function index. In a multiple linear regression analysis, LP-PLA2 and sPLA2 were independent correlative factors of HOMA-IR(both P<0. 05). Conclusions Plasma levels of LP-PLA2 and sPLA2 were significantly higher in patients with newly diagnosed type 2 diabetes than in individuals with normal glucose tolerance, even more significant in diabetic patients with atherosclerosis. And their concentrations were both closely related to insulin resistance.
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Secretory phospholipase A2 group II A is an enzyme that hydrolyzes the sn-2 ester in glyceroacyl phospholipids present in lipoproteins and cell membranes. There have been an increasing number of reports regarding the pathogenesis of the enzyme in cardiovascular,tumor and autoimmune diseases in recent years and drug development targeting the enzyme is receiving more and more attention as a result. This article reviews research results in the above areas and current status of drug development based on reported sPLA2-II inhibitors.
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Objective To explore the role and significance of secretory phospholipase A2(sPLA2)in peripheral blood in preterm premature rup?ture of membranes(pPROM)and infection of amniotic cavity. Methods RT-PCR was used to detect the expression levels of sPLA2 mRNA in pe?ripheral blood of 30 patients with pPROM (experimental group),30 non-full term normal pregnant patients without pPROM (normal control group)and 30 full term patients with PROM(full-term control group)before and after delivery. Fetal membranes were collected at the time of deliv?ery of patients with pPROM for pathologic examination to determine histological chorioamnionitis(HCA). Results The expression levels of sPLA2 mRNA in peripheral blood were 1.079±0.746 and 0.651±0.481 in the experimental group and the normal control group before delivery,respectively, indicating that the expression of sPLA2 mRNA was increased in the experimental group compared with the normal control group(P=0.011). The expression levels of sPLA2 mRNA in peripheral blood were 2.439±0.086 and 2.575±0.036 in the experimental group and the full-term control group at labor onset,respectively,indicating that there was no statistically significant difference in the level of sPLA2 mRNA in peripheral blood between the experimental group and the full-term control group at labor onset(P=0.787). The level of sPLA2 was related to chorioamnionitis in the experi?mental group at labor onset. Conclusion The increase of sPLA2 may participate in the pathogenesis of preterm premature rupture of membranes and is related with the infection of chorioamnionitis.
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Background & objectives: Secretory phospholipase A2 (sPLA2) and oxidized low density lipoprotein (oxLDL) are considered as oxidative and inflammatory markers. The effects of oxLDL have been shown to be inhibited by paraoxonase (PON1). This study was undertaken to investigate the relationship between oxidative and inflammatory markers in hypertensive patients with or without antihypertensive drug treatment. Methods: Newly diagnosed hypertensive patients (n=35) and hypertensive patients who had been taking angiotensin converting enzyme (ACE) inhibitors as antihypertensive therapy (10 or 20 mg/day for 9 ± 2 wk; n=35) and age-matched normotensive subjects (controls; n=20) were included in this study. Plasma sPLA2, oxLDL and PON1 activities were determined. Results: Hypertensives had higher plasma oxLDL and sPLA2 levels (P<0.01) and lower PON1 levels than the controls (P<0.01). Treated hypertensives had lower plasma sPLA2 and oxLDL levels and higher PON1 activities than hypertensives (P<0.01). sPLA2 was positively correlated with oxLDL (r=0.433, P<0.01) and negatively correlated with plasma PON1 (r= - 0.540, P<0.01) in untreated hypertensives. In controls and treated hypertensives, plasma PON1 was positively correlated with oxLDL (r= 0.455, r=0.429, P<0.01, respectively) and sPLA2 (r= 0.450, r=0.506, P<0.01, respectively). Interpretation & conclusions: Reduction in PON1 activity and elevation in both sPLA2 activities and oxLDL levels might be involved in elevated oxidative stress and inflammation. ACE inhibitor treatment may help reduce inflammation and oxidative stress in hypertensives.
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Objective To investigate the expression and signficance of secretory phospholipase A2(sPLA2>) in gastric adenocareinoma. Methods Sixty-five samples of gastric adenocarcinoma (11 with high differentiation, 10 with median differentiation and 44 with low differentiation) and 11 samples of normal gastric mucosa had been obtained from the Second Affiliated Hospital of Jilin University from January 2006 to April 2007. Fifty samples of gastric adenocarcinoma were found with lymph node metastasis. The expression of sPLA2> in gastric adenocarcinoma and normal gastric mucosa was detected. The relationship between sPLA2> and the differentiation of gastric adenoearcinoma, lymph node metastasis and helicobacter pylori infection was detected. All the data were processed with chi-square test or Spearman rank correlation. Results The positive rates of the sPLA2> expression in normal gastric mucosa and gastric adenocarcinoma were 36% (4/11) and 78% (51/65). The positive rates of sPLA2> expression in low, median and high differentiated gastric adenocarcinoma were 84% (37/44), 70% (7/10) and 64% (7/11), respectively. The expression of sPLA2> was positively correlated with the malignancy of gastric adenocarcinoma (r =0.272, P <0.05). The positive rates of sPLA2> expression in gastric adenocarcinoma with and without lymph node metastasis were 88% (44/50) and 47% (7/15), respectively. The expression of sPLA2> was correlated with lymph node metastasis (X2 = 9. 347, P < 0.05). The positive rates of sPLA2> expression in gastric adenocarcinoma with and without helicobacter pylori infection were 79% (38/48) and 76% (13/17), respectively. The expression of sPLA2> was not correlated with helicobacter pylori infection (X2 = 0. 000, P > 0.05). Conclusions The activation of sPLA2> gene may be correlated with the genesis of gastric adenocarcinoma. sPLA2> may influence the invasion of gastric adenocarcinoma, and can be used as an indicator in predicting poor prognosis.
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Cobra venom secretory phospholipase A_2 (sPLA_2) is an important component of cobra venom which has a variety of biological activities. Recent studies are mainly focusing on each pharmacological active component of venom, SPLA_2 is one of them. This review summarized the structure, purification and biological activities of cobra venom sPLA_2 with emphasizing its diverse pharmacological effects and toxicity. In addition, some mechanisms of actions of sPLA_2 and possible applications of sPLA_2 were also discussed.