Evaluating the inhibitory potential of Withania somnifera on platelet aggregation and inflammation enzymes: An in vitro and in silico study

Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation.

Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes.

Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark).

Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC₅₀ value of 13.8?mg/mL on PLA₂ from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC₅₀ value of 16.6?mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC₅₀ value of 0.92?mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of??128.96 compared to standard phenidone (?103.61). Thus, the current study validates the application of WS for inflammatory diseases.

Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases.     

Involvement of glutamate receptors,lipases, and phospholipases in long-term potentiation and neurodegeneration

Glutamate is the primary excitatory amino acid in the mammalian central nervous system. Normal excitation of glutamate receptors initiates the stimulation of phospholipases and lipases with the generation of second messengers that are necessary for normal cell function. The overstimulation of glutamate receptors can initiate a cascade of biochemical events including stimulation of membrane phospholipid turnover, excessive calcium entry, abnormal phosphorylation, and proteolysis. These events may be responsible for neuronal injury and degeneration found in Alzheimer disease, ischemia, spinal cord trauma, epilepsy, and Huntington disease.     

Upregulated phospholipase D2 expression and activity is related to the metastatic properties of melanoma

The incidence rates of melanoma have increased steadily in recent decades and nearly 25% of the patients diagnosed with early-stage melanoma will eventually develop metastasis, for which there is currently no fully effective treatment. The link between phospholipases and tumors has been studied extensively, particularly in breast and colon cancers. With the aim of finding new biomarkers and therapeutic options for melanoma, the expression of different phospholipases was assessed in 17 distinct cell lines in the present study, demonstrating that phospholipase D2 (PLD2) is upregulated in metastatic melanoma as compared to normal skin melanocytes. These results were corroborated by immunofluorescence and lipase activity assays. Upregulation of PLD2 expression and increased lipase activity were observed in metastatic melanoma relative to normal skin melanocytes. So far, the implication of PLD2 activity in melanoma malignancies has remained elusive. To the best of our knowledge, the present study was the first to demonstrate that the overexpression of PLD2 enhances lipase activity, and its effect to increase the proliferation, migration and invasion capacity of melanoma cells was assessed with XTT and Transwell assays. In addition, silencing of PLD2 in melanoma cells reduced the metastatic potential of these cells. The present study provided evidence that PLD2 is involved in melanoma malignancy and in particular, in its metastatic potential, and established a basis for future studies evaluating PLD2 blockade as a therapeutic strategy to manage this condition.     

Distribution and hydrolytic enzyme characteristics of Candida albicans strains isolated from diabetic patients and their non-diabetic consorts

Introduction:  The aim of this study was to investigate the oral colonization profile of Candida albicans strains isolated from diabetic patients and their non-diabetic consorts. In addition hydrolytic enzyme activity of these isolates was analysed.
Methods:  The genetic diversity of C. albicans oral isolates from 52 couples was established using isoenzyme marker and cluster analysis. Hydrolytic enzyme characteristics, namely secreted aspartyl proteinases (SAPs) and phospholipases (PLs) were also analysed.
Results:  Simultaneous colonization by C. albicans was observed in the consorts of 12 couples (23.1%). Patterns of monoclonal and polyclonal oral colonization by C. albicans strains were identified and the coexistence of identical or highly related strains was observed in both members of eight couples. The genetic diversity observed in the total yeast population revealed four large, genetically distinct groups (A to D) and the coexistence of strains in couples or consorts conjugally unrelated. SAP and PL activity was observed in the majority of C. albicans isolates without any association to particular strain, strain clusters (highly related isolates), or clinical characteristics of the consorts (diabetic, non-diabetic, and gender).
Conclusion:  Possible sources of transmission and oral propagation of groups (clusters) of strains of C. albicans can occur between diabetic and non-diabetic consorts. A conjugal genotypic identity exists in most C. albicans -positive couples, that is, both consorts share identical or highly related strains; however, this identity is not couple-specific as seen by the coexistence of clusters in couples and unrelated consorts.     

Systemic and local myotoxicity induced by snake venom group II phospholipases A2: comparison between crotoxin, crotoxin B and a Lys49 PLA2 homologue.

The patterns of myotoxicity induced in mice by crotoxin, crotoxin B and a Lys49 phospholipase A(2) (PLA(2)) homologue were compared. Lys49 PLA(2)-induced local myotoxicity is reflected by creatine kinase (CK) loss in injected gastrocnemius muscle, and by a profile of CK increase in plasma characterized by a rapid increment and drop after intramuscular injection, and by a lack of CK increase in plasma after intravenous injection. In contrast, crotoxin and crotoxin B, which induce local and systemic myotoxicity, provoked a more prolonged increment in plasma CK activity upon intramuscular injection, and induced increments in plasma CK after intravenous injection. The three toxins promoted a similar extent of local myotoxicity, assessed by the loss of CK in injected gastrocnemius. A method for the quantitative assessment of the ability of toxins to induce systemic myotoxicity is proposed, based on the estimation of the ratio between the area under the curve in the plasma CK activity (total myotoxicity) to the loss of CK in injected gastrocnemius (local myotoxicity). The highest ratio corresponded to crotoxin, and the lowest corresponded to Lys49 PLA(2), the former being a systemic myotoxin and the latter a local myotoxin. Neutralization by antivenoms also differed between the toxins: a drastic reduction in plasma CK, with very poor neutralization of local CK loss, was achieved in the case of crotoxin B when antivenom was injected intravenously, whereas no neutralization was achieved in the case of Lys49 PLA(2). When tested in undifferentiated myoblasts in culture, Lys49 PLA(2) induced cytotoxicity, whereas crotoxin and crotoxin B did not, evidencing that the latter are devoid of widespread cytolytic activity. Molecular modeling analysis showed that Lys49 PLA(2) has a conspicuous cationic face, which is likely to interact with diverse membranes. In contrast, crotoxin B, despite its overall basic pI, has a lower density of positively charged residues at this molecular region. It is suggested that Lys49 PLA(2)s homologues interact, through this cationic face, with many different cell types, thus lacking specificity for muscle cells. In contrast, crotoxin B has a more selective interaction with targets in the muscle cell membrane. This selectivity might be the basis for the ability of crotoxin and crotoxin B to induce systemic myotoxicity.     

Phospholipases of Candida albicans

Infections due to Candida albicans are frequent and of clinical importance. Especially at a time of increasing organ transplantations, HIV infections, and resistance to antimicrobial agents a profound knowledge of the interaction between C. albicans and host tissue is mandatory. In addition to secreted aspartyl proteinase, dimorphism, cell surface composition, and toxin production phospholipases are a main factor in pathogenicity. Up to the present, many different groups and subgroups of phospholipases have been detected. These different enzymes are related to various types of aggressive and defensive actions. These range from active invasion of host cell tissue to growth control and remodelling of the yeast cell membrane. It is clear that a multiplicity of factors must co-operate to overcome the host's defences. Yet it can be supposed today that phospholipases are one important factor in this complex interaction. Therefore the known phospholipases of C. albicans are described in detail under clinical aspects.     

磷脂酶Cε1的过表达可抑制结肠癌SW6 20细胞的迁移并诱导其凋亡

目的:探讨磷脂酶Cε1(phospholipase C epsilon-1,PLCE1)基因过表达对结肠癌细胞迁移、细胞周期及凋亡等生物学特性的影响。方法:采用脂质体转染的方法建立PLCE1过表达的SW620细胞株,实验分为3组:亲本细胞组(未转染基因),对照组[转染含绿色荧光蛋白(greenfluorescent protein,GFP)的空质粒],实验组(转染质粒pcDNA-DEST53-PLCE1)。分别采用实时荧光定量-PCR(real-time fluorogenic quantitative-PCR,RFQPCR)和蛋白质印迹法检测PLCE1 mRNA和蛋白在SW620细胞中的表达;Transwell小室法检测PLCE1过表达对SW620细胞迁移能力的影响,FCM法检测对细胞周期及凋亡率的影响,DNA Ladder法检测对细胞凋亡的影响。结果:PLCE1过表达可抑制结肠癌SW620细胞的迁移能力,实验组迁移细胞数为(8.80±1.72)个,而亲本组和对照组分别为(32.6±2.42)和(32.2±3.25)个,3组间差异有统计学意义(P<0.01)。PLCE1过表达可导致结肠癌细胞周期G1期延长,并出现凋亡。结论:PLCE1过表达可抑制结肠癌细胞的迁移能力,并引起细胞凋亡。PLCE1基因过表达使SW620结肠癌细胞恶性程度降低,该基因可能是新的结肠癌相关抑癌基因。     

醋酸铅对大鼠脑皮质区细胞超微结构钙分布和酶活性的影响

用电镜钙细胞化学定位法和酶组织化学亚微数字图像分析系统，观察了断奶ｄ１起，分别给饮用１０和３０ｍｇ·Ｌ－１Ｐｂ２＋水３个月的幼鼠脑组织．发现血铅浓度为对照组１．６５倍时，细胞内钙分布和超微结构无明显变化．血铅浓度为对照组２．４５倍时，脑铅含量增加，Ｃａ２＋－ＡＴＰ酶活性降低，磷脂酶活性增加，钙细胞化学观察见各种细胞的钙分布和超微结构均已发生了变化．结果显示：３０ｍｇ·Ｌ－１的铅染毒量即能引起幼鼠脑皮质区细胞钙代谢的恶性循环，如不给予阻断可能导致细胞进一步损伤．     

The effect of thrombin on the uptake and transformation of arachidonic acid by human platelets

Washed human platelets take up arachidonic acid from plasma and incorporate the fatty acid into the major classes of complex lipids. Thrombin impairs net incorporation. It activates endogenous phospholipases which liberate arachidonic acid from phospholipids. As a consequence of thrombin induced aggregation platelets release arachidonic acid intermediates formed by the action of platelet fatty acid cyclooxygenase and by platelet fatty acid lipoxygenase. Cyclooxygenase, but not lipoxygenase, is inhibited by aspirin and indomethicin. Analysis of the pathways of arachidonic acid metabolism may furnish new insight into platelet function and into disorders of primary hemostasis.