Phospholipase A2 Research Articles

Sphingomyelin Inhibits Hydrolytic Activity of Heterodimeric PLA2 in Model Myelin Membranes: Pharmacological Relevance.

In this work, the heterodimeric phospholipase A2, HDP-2, from viper venom was investigated for its hydrolytic activity in model myelin membranes as well as for its effects on intermembrane exchange of phospholipids (studied by phosphorescence quenching) and on phospholipid polymorphism (studied by 1H-NMR spectroscopy) to understand the role of sphingomyelin (SM) in the demyelination of nerve fibers. By using well-validated in vitro approaches, we show that the presence of SM in model myelin membranes leads to a significant inhibition of the hydrolytic activity of HDP-2, decreased intermembrane phospholipid exchange, and reduced phospholipid polymorphism. Using AutoDock software, we show that the NHδ+ group of the sphingosine backbone of SM binds to Tyr22(C=Opbδ-) of HDP-2 via a hydrogen bond which keeps only the polar head of SM inside the HDP-2's active center and positions the sn-2 acyl ester bond away from the active center, thus making it unlikely to hydrolyze the alkyl chains at the sn-2 position. This observation strongly suggests that SM inhibits the catalytic activity of HDP-2 by blocking access to other phospholipids to the active center of the enzyme. Should this observation be verified in further studies, it would offer a tantalizing opportunity for developing effective pharmaceuticals to stop the demyelination of nerve fibers by aberrant PLA2s with overt activity - as observed in brain degenerative diseases - by inhibiting SM hydrolysis and/or facilitating SM synthesis in the myelin sheath membrane.

The impact of trauma relevant concentrations of prostaglandin E2 on the anti-microbial activity of the innate immune system.

The mechanisms underlying the state of systemic immune suppression that develops following major trauma are poorly understood. A post-injury increase in circulating levels of prostaglandin E2 (PGE2) has been proposed as a contributory factor, yet few studies have addressed how trauma influences PGE2 biology. Blood samples from 95 traumatically-injured patients (injury severity score ≥8) were collected across the pre-hospital (≤2 hours), acute (4-12 hours) and subacute (48-72 hours) post-injury settings. Alongside ex vivo assessments of lipopolysaccharide (LPS)-induced cytokine production by monocytes, neutrophil reactive oxygen species production and phagocytosis, serum concentrations of PGE2 and its scavenger albumin were measured, and the expression of enzymes and receptors involved in PGE2 synthesis and signalling analysed. Leukocytes from trauma patients were treated with cyclooxygenase (COX) inhibitors (indomethacin or NS-398), or the protein kinase A inhibitor H89, to determine whether injury-induced immune suppression could be reversed by targeting the PGE2 pathway. The effect that trauma relevant concentrations of PGE2 had on the anti-microbial functions of neutrophils, monocytes and monocyte-derived macrophages (MDMs) from healthy controls (HC) was examined, as was the effect of PGE2 on efferocytosis. To identify factors that may trigger PGE2 production post-trauma, leukocytes from HC were treated with mitochondrial-derived damage associated molecular patterns (mtDAMPs) and COX-2 expression and PGE2 generation measured. PGE2 concentrations peaked in blood samples acquired ≤2 hours post-injury and coincided with significantly reduced levels of albumin and impaired LPS-induced cytokine production by monocytes. Significantly higher COX-2 and phospholipase A2 expression was detected in neutrophils and/or peripheral blood mononuclear cells isolated from trauma patients. Treatment of patient leukocytes with indomethacin, NS-398 or H89 enhanced LPS-induced cytokine production and neutrophil extracellular trap generation. Exposure to physiological concentrations of PGE2 suppressed the anti-microbial activity of monocytes, neutrophils and MDMs of HC, but did not influence efferocytosis. In a formyl-peptide receptor-1 dependent manner, mtDAMP treatment significantly increased COX-2 protein expression in neutrophils and monocytes, which resulted in increased PGE2 production. Physiological concentrations of PGE2 suppress the anti-microbial activities of neutrophils, monocytes and MDMs. Targeting the PGE2 pathway could be a therapeutic approach by which to enhance innate immune function post-injury.

Hydrolysis of phospholipid monolayers by phospholipase A2 revealed by heterodyne-detected sum frequency generation (HD-SFG) spectroscopy.

Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 acyl ester linkage in phospholipid, producing lysophospholipid and fatty acid in the presence of Ca2+. The hydrolysis mediated by PLA2 has attracted much interest in various fields, such as pharmacy and biotechnology. It is recognized that PLA2 cannot hydrolyze phospholipid monolayers at high surface coverage. However, the origin of different PLA2 activities is not fully understood yet. The present study investigated the interaction between DPPC (16:0 PC) monolayer and PLA2 using heterodyne-detected sum frequency generation spectroscopy, which is interface-specific spectroscopy and highly sensitive to molecular symmetry based on a second-order nonlinear optical process. It was revealed that PLA2 adsorbs to the DPPC monolayer on the aqueous solution surface only when the surface coverage is low. The adsorption at the low surface coverage significantly changes the interfacial structures of PLA2 and the hydration, which are stabilized by the presence of Ca2+. Therefore, the restriction of the hydrolysis of phospholipid monolayers at high surface coverage can be rationalized by the inhabitation of the PLA2 adsorption. The present study deepens our molecular-level understanding of the hydrolysis of phospholipids by PLA2.

Metformin suppresses metabolic dysfunction-associated fatty liver disease by ferroptosis and apoptosis via activation of oxidative stress

Metformin is known for its antioxidant properties and ability to ameliorate metabolic dysfunction-associated fatty liver disease (MAFLD) and is the focus of this study. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is linked to MAFLD risk. This study investigated the effects of metformin on ferroptosis in free fatty acid (FFA)-treated Huh7 hepatoma cells and its association with MAFLD risk. Using Western blot, immunofluorescence, and ELISA, this study revealed that FFA treatment led to increased intracellular fat and iron accumulation, heightened Lp-PLA2 expression, reduced levels of the cysteine transporter SLC7A11 and glutathione peroxidase 4 (GPX4), altered glutathione (GSH)/oxidized glutathione (GSSG) ratios, generation of reactive oxygen species (ROS), and initiation of lipid peroxidation, which ultimately resulted in cell ferroptosis. Importantly, metformin reversed FFA-induced iron accumulation, and this effect was attenuated by ferrostatin-1 but enhanced by erastin, RSL3, and si-GPX4. Additionally, metformin activated antioxidant and antiapoptotic mechanisms, which reduced lipid peroxidation and suppressed Lp-PLA2 expression in FFA-treated Huh7 cells. In conclusion, our findings indicate that metformin may protect against MAFLD by inhibiting iron accumulation and Lp-PLA2 expression through the ROS, ferroptosis, and apoptosis signaling pathways. This study highlights potential therapeutic strategies for managing MAFLD-related risks and emphasizes the diverse roles of metformin in maintaining hepatocyte balance.

Cytosolic Phospholipase A2 in Infiltrating Monocyte-Derived Macrophages Does Not Impair Recovery After Spinal Cord Injury in Female Mice.

Spinal cord injury (SCI) leads to permanent motor and sensory loss that is exacerbated by intraspinal inflammation that persists months to years after injury. After SCI, monocyte-derived macrophages (MDMs) infiltrate the lesion to aid in myelin-rich debris clearance. During debris clearance, MDMs adopt a proinflammatory phenotype that exacerbates neurodegeneration and hinders recovery. The underlying cause of the lipid-mediated MDM phenotype shift is unclear. Our previous work suggests that cytosolic phospholipase A2 (cPLA2) plays a role in the proinflammatory potentiating effect of myelin on macrophages in vitro . Cytosolic phospholipase A2 (cPLA2) frees arachidonic acid from phospholipids, generating eicosanoids that play an important role in inflammation, immunity, and host defense. cPLA2 is expressed in macrophages along with multiple other cell types after SCI, and cPLA2 inhibition has been reported to both reduce and exacerbate secondary injury pathology recovery. The role of cPLA2 in MDMs after SCI is not fully understood. We hypothesize that cPLA2 activation in MDMs after SCI contributes to secondary injury. Here, we report that cPLA2 plays an important role in the myelin-induced inflammatory macrophage phenotype in vitro using macrophages derived from cPLA2 knockout bone marrow. Furthermore, to investigate the role of cPLA2 in MDMs after SCI, we generated female bone marrow chimeras using cPLA2 knock-out donors and assessed locomotor recovery using the Basso Mouse Scale (BMS), CatWalk gait analysis system, and horizontal ladder task over six weeks. We also evaluated tissue sparing and intralesional axon density six weeks after injury. cPLA2 KO chimeras did not display altered locomotor recovery or tissue pathology after SCI compared to WT chimera controls. These data suggest that although cPLA2 plays a critical role in myelin-mediated potentiation of proinflammatory macrophage activation in vitro , it may not contribute to secondary injury pathology in vivo after SCI.

Epitope Spreading in Immune-Mediated Glomerulonephritis: The Expanding Target

Epitope spreading is a critical mechanism driving the progression of autoimmune glomerulonephritis. This phenomenon, where immune responses broaden from a single epitope to encompass additional targets, contributes to the complexity and severity of diseases such as membranous nephropathy (MN), lupus nephritis (LN), and ANCA-associated vasculitis (AAV). In MN, intramolecular spreading within the phospholipase A2 receptor correlates with a worse prognosis, while LN exemplifies both intra- and intermolecular spreading, exacerbating renal involvement. Similarly, ANCA reactivity in AAV highlights the destructive potential of epitope diversification. Understanding these immunological cascades reveals therapeutic opportunities—targeting early epitope spreading could curb disease progression. Despite promising insights, the clinical utility of epitope spreading as a prognostic tool remains debated. This review provides a complete overview of the current evidence, exploring the dual-edged nature of epitope spreading, the intricate immune mechanisms behind it, and its therapeutic implications. By elucidating these dynamics, we aim to pave the way for more precise, targeted interventions in autoimmune glomerular diseases.

Facial Amphiphile-Modified Lipids Highly Sensitize Liposomes toward Secretory Phospholipase A2.

Upregulated secretory phospholipase A2 (sPLA2) in tumors has been proposed as a stimulus to trigger drug release from liposomes for therapeutic effects. However, the current strategy for developing sPLA2-responsive liposomes merely considering substrate preference suffers from limited membrane disruptive effects induced by enzymatic hydrolysis and safety issues resulting from the overuse of sPLA2-preferred lipids. Here, a membrane-destabilizing mechanism based on enzymatic extraction and the transition of facial amphiphiles (FAs) within lipid membranes was introduced. Enzymatic degradation of FA-modified lipids, a process involving substrate extraction of lipids from membranes and cleavage of sn-2 ester bonds by sPLA2, rotation, and interface settling of detached FAs, caused tremendous efflux of payloads from liposomes, termed the SECRIS effect. In the presence of sPLA2, oxaliplatin (L-OHP) loaded liposomes containing FA-modified lipids showed enhanced drug release, comparable in vitro cytotoxicity, and excellent in vivo antitumor efficacy and reduced adverse syndromes in Colo205-bearing mice compared to conventional sPLA2-labile formulations. The discovery of the SECRIS effect creates a new pathway to engineer liposome platforms for the treatment of sPLA2-positive tumors.

The Toxin Diversity, Cytotoxicity, and Enzymatic Activity of Cape Cobra (Naja nivea) Venom.

"True" cobras (genus Naja) are among the venomous snakes most frequently involved in snakebite accidents in Africa and Asia. The Cape cobra (Naja nivea) is one of the African cobras of highest medical importance, but much remains to be learned about its venom. Here, we used a shotgun proteomics approach to better understand the qualitative composition of N. nivea venom and tested its cytotoxicity and protease activity as well as its effect on intracellular Ca2+ release and NO synthesis. We identified 156 venom components representing 17 protein families, with the dominant ones being three-finger toxins, mostly of the short-chain type. Two-thirds of the three-finger toxin entries identified were assigned as cytotoxins, while the remainder were categorized as neurotoxins, including short-chain, long-chain, and ancestral three-finger toxins. We also identified snake venom metalloproteinases and members of CRISP, l-amino acid oxidase, and other families. Protease activity and its effect on intracellular Ca2+ release and NO synthesis were low. Phospholipase A2 activity was surprisingly high, despite this toxin family being marginally recovered in the analyzed venom. Cytotoxicity was relevant only at higher venom concentrations, with macrophage and neuroblastoma cell lines showing the lowest viability. These results are in line with the predominantly neurotoxic envenomation symptoms caused by Cape cobra bites. The present overview of the qualitatively complex and functionally intriguing venom of N. nivea may provide insights into the pathobiochemistry of this species' venom.

The Protective Effect of the Supplementation with an Extract from Aronia melanocarpa L. Berries against Cadmium-Induced Changes of Chosen Biomarkers of Neurotoxicity in the Brain-A Study in a Rat Model of Current Lifetime Human Exposure to This Toxic Heavy Metal.

Since even low-level environmental exposure to cadmium (Cd) can lead to numerous unfavourable health outcomes, including damage to the nervous system, it is important to recognize the risk of health damage by this xenobiotic, the mechanisms of its toxic influence, and to find an effective protective strategy. This study aimed to evaluate, in a female Wistar rat model of current human environmental exposure to Cd (1 and 5 mg/kg of diet for 3-24 months), if the low-to-moderate treatment with this element can harm the brain and whether the supplementation with a 0.1% Aronia melanocarpa L. (Michx.) Elliott berries (chokeberries) extract (AE) can protect against this effect. The exposure to Cd modified the values of various biomarkers of neurotoxicity, including enzymes (acetylcholinesterase (AChE), sodium-potassium adenosine triphosphatase (Na+/K+-ATPase), phospholipase A2 (PLA2), and nitric oxide synthase 1 (NOS1)) and non-enzymatic proteins (calmodulin (CAM), nuclear factor erythroid 2-related factor 2 (Nrf2), and Kelch-like ECH-associated protein 1 (KEAP1)) crucial for the functioning of the nervous system, as well as the concentrations of calcium (Ca) and magnesium (Mg) and some metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in the brain tissue. The co-administration of AE, partially or entirely, protected from most of the Cd-induced changes alleviating its neurotoxic influence. In conclusion, even low-level chronic exposure to Cd may adversely affect the nervous system, whereas the supplementation with A. melanocarpa berries products during the treatment seems a protective strategy.

The Synergistic and Opposing Roles of ω-Fatty Acid Hydroxylase (CYP4A11) and ω-1 Fatty Acid Hydroxylase (CYP2E1) in Chronic Liver Disease

Cytochrome P450 fatty acid hydroxylase consists of members of the CYP4 family that ω-hydroxylate fatty acids and the CYP2E1 that ω-1 hydroxylates fatty acids. Although ω and ω-1 hydroxylation of fatty acids have been thought to play a minor role in fatty acid metabolism (less than 20%), it plays a vital role in excess liver fatty acids overload seen in fasting, diabetes, metabolic disorder, and over-consumption of alcohol and high-fat diet. This pathway provides anabolic metabolites for gluconeogenesis, succinate, and acetate for lipogenesis. The CYP4A and CYP2E1 genes are activated in fasting and several metabolic disorders, suggesting a synergistic role in preventing fatty acid-induced lipotoxicity with the consequence of increased liver cholesterol and lipogenesis leading to increased Lipid Droplet (LD) deposition. During the progression of Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD), activation of Phospholipase A2 (PLA2) releases arachidonic acid that CYP4A11 and CYP2E1 P450s metabolize to produce 20-hydroxyeicosatetraenoic acid (20-HETE) and 19-HETE, respectively. These metabolites have opposing roles in the progression of MASLD and chronic liver disease (CLD). This report discusses the synergistic role of the CYP4A and CYP2E1 P450s in the metabolism of saturated and unsaturated fatty acids and their opposite physiological role in the metabolism of Arachidonic Acid (AA). We finally discuss the role of ethanol in disrupting the synergistic and opposing roles of the CYP4A and CYP2E1 genes in MASLD and CLD.

Unwinding the Threads of Mesoporous Silica Nanoparticles as Cutting-Edge for the Management of Inflammation: An Updated Review.

Inflammation serves as a protective response to combat cellular and tissue damage. There is currently a wide array of synthetic and traditional therapies available for the treatment of inflammatory diseases. However, it is necessary to create a drug delivery system based on nanotechnology that can improve the solubility, permeability, and bioavailability of current treatments. Mesoporous silica nanoparticles (MSNPs) are inorganic materials known for their organised porous interiors, high pore volumes, substantial surface area, exceptional selectivity, permeability, low refractive index, and customisable pore sizes. This review offers concise insights into the progression of the pathophysiology of inflammation, as well as the inducers, mediators, and effectors that are involved in the inflammatory pathway. This study focuses on the growing significance of MSNPs in the treatment of neuroinflammation, inflammatory bowel disease, arthritic inflammation, lung inflammation, and wound healing applications. This review also presents the latest information on the crucial role of MSNPs in delivering herbal medicines for the treatment of inflammation. A comprehensive literature search was conducted for this aim, utilising the Google Scholar, PubMed, and ScienceDirect databases. A systematic review was undertaken utilising scholarly articles published in peer-reviewed journals from 2000 to 2024. The inflammatory mediators involved in the pathophysiology of inflammation include platelet-activating factor, lipoxygenase, cyclooxygenase, Interferon-α, interleukin-6, interleukin- 1β, matrix metalloproteinases, inducible nitric oxide synthase, nuclear factor-κB, prostaglandins, nitric oxide, and phospholipase A2. MSNPs have the potential to be used in the treatment of neuroinflammation, inflammatory bowel disease, arthritic inflammation, lung inflammation, and wound healing. The investigation of the MSNPs of plant-based compounds such as berberine, tetrahydrocannabinol, curcumin, and resveratrol has shown successful results in recent years for the purpose of managing inflammation. This review demonstrates that MSNPs have a strong potential to play a positive role in delivering synthetic and plant-based therapies for the treatment of inflammatory illnesses.

A Clinicopathological Analysis of Membranous Nephropathy and Its Correlation With the Immunohistochemical Expression of Phospholipase A2 Receptor (PLA2R) in Renal Biopsies in a Tertiary Care Center.

Background Membranous nephropathy (MN) is the second most common adult-onset nephrotic syndrome worldwide. Traditionally, these were classified as primary and secondary, with primary causes showing higher positivity for various antigens, includingM-typephospholipase A2 receptor (PLA2R), a key antigen located in the podocyteagainstwhich antibodies are directed. Aim The aim of this study is to analyze the cases diagnosed as MN with clinicopathological parameters and PLA2R positivity by immunohistochemistry in renal biopsies. Methods A retrospective observational study of 65 cases of MN diagnosed in renal biopsiesby light microscopy and confirmed by ancillary studies from the Department of Pathology, Sri Ramachandra Medical College and Research Institute over a period of three years (2021-2023). The demographic profile and patient details were obtained from the hospital information system and archival case files.The description of categorical variables was expressed as frequency and percentage. The Chi-squared test and Fisher's exact test were employed to compare the distribution of qualitative variables between the groups. Results This case study includes 65 membranous nephropathy cases, of which 47.7% were diagnosed as primary MN and 52.3% as secondary MN. Of these, serum antinuclear antibody (ANA) positivity was seen in 80.6% of cases of primary MN and 58.8% of cases of secondary MN. Elevated serum C3/C4 levels were noted in 51.6% of primary MN and 47.1% of secondary MN (Ref. C3 = 90-180mg/dl; C4 = 10-40mg/dl). Immunofluorescence for IgG showed a nonspecificassociation between primary and secondary MN. Immunohistochemistry (IHC) for PLA2R showed positivity in 72.3% of primary MN cases and 27.7% of secondary MN cases. The Chi-squared test and Fisher's exact test showed statistical significance for these parameters. Conclusion This study signifies that primary MN is more frequently associated with positive immunohistochemical expression of PLA2R. These findings help in characterizing these cases as antigen-specific and have helped in the ongoing validation ofPLA2R IHC as a diagnostic marker, which aids in monitoring the disease progression, remission, and recurrence. Despite the availability ofvarious modalities for estimating the levels of anti-PLA2R, diagnostic challenges persist. Hence, most renal laboratories continue to adopt renal biopsy stainingfor IHC PLA2R to identify and monitor the disease progression.

Individual variation in Macrovipera lebetinus obtusa (blunt-nosed viper) venom from a limited area in Southeastern Anatolia (Türkiye)

Intraspecific variation in snake venom composition has been the subject of many studies, revealing the differences in venom proteomes according to age, diet, sex, and geographic region. Previous research on M. lebetinus venom mainly focused on protein purification, proteomic characterization, and biological activities. Although venom proteomes of its subspecies from different geographical areas were compared, it is a widespread species and there is limited knowledge regarding the individual venom variation of M. lebetinus in the same area. In this study, individual variation in M. lebetinus obtusa venom was investigated in terms of protein profiles, protease, phospholipase A2, ʟ-amino acid oxidase, hyaluronidase and phosphodiesterase, and hemolytic activities based on nine individuals collected in the province of Şanlıurfa (southeastern Türkiye). HPLC analysis indicated more striking differences compared to SDS-PAGE. Phosphodiesterase activity varied most between the individuals, followed by hyaluronidase and phospholipase A2. Hemolytic activity did not show significant alteration based on the blood agar method. The results of this initial study revealed that M. lebetinus venom shows variation between the individuals inhabiting the same habitat, which should be taken into account in the development of antivenoms and the clinical assessment of the bite cases.

Preparation and characterization of niosomes for the delivery of a lipophilic model drug: comparative stability study with liposomes against phospholipase-A2

Vesicular nanocarriers like niosomes and liposomes are widely researched for controlled drug delivery systems, with niosomes emerging as promising alternatives due to their higher stability and ease of manufacturing. This study aimed to develop and characterize a niosomal formulation for the encapsulation and sustained release of temozolomide (TMZ), a model lipophilic drug, and to compare the stability of niosomes and liposomes, with a particular focus on the behavior of their lipid bilayers. Niosomes were prepared using the thin-film hydration method, composed of Span 60 (Sorbitan monostearate), cholesterol, and soy lecithin in varying molar ratios. The study investigated critical properties such as drug loading capacity, release kinetics, and resistance to enzymatic degradation. The optimized formulation was analyzed for drug entrapment efficiency and stability against phospholipase A2 (PLA2) degradation. The optimized niosomal formulation, with a 4:2:1 molar ratio of Span 60: cholesterol, achieved a high TMZ entrapment efficiency of 73.23 ± 1.02% and demonstrated sustained drug release over 24 hours. In comparison, liposomes released their TMZ payload within 4 hours upon exposure to PLA2, while the niosomes maintained their release profile, indicating superior stability. Spectroscopic and thermal analysis confirmed successful drug encapsulation with no component incompatibilities.

Phospholipids, Sphingolipids, and Cholesterol-Derived Lipid Mediators and Their Role in Neurological Disorders.

Neural membranes are composed of phospholipids, sphingolipids, cholesterol, and proteins. In response to cell stimulation or injury, the metabolism of lipids generates various lipid mediators, which perform many cellular functions. Thus, phospholipids release arachidonic acid or docosahexaenoic acid from the sn-2 position of the glycerol moiety by the action of phospholipases A2. Arachidonic acid is a precursor for prostaglandins, leukotrienes, thromboxane, and lipoxins. Among these mediators, prostaglandins, leukotrienes, and thromboxane produce neuroinflammation. In contrast, lipoxins produce anti-inflammatory and pro-resolving effects. Prostaglandins, leukotrienes, and thromboxane are also involved in cell proliferation, differentiation, blood clotting, and blood vessel permeability. In contrast, DHA-derived lipid mediators are called specialized pro-resolving lipid metabolites (SPMs). They include resolvins, protectins, and maresins. These mediators regulate immune function by producing anti-inflammatory, pro-resolving, and cell protective effects. Sphingolipid-derived metabolites are ceramide, ceramide1-phosphate, sphingosine, and sphingosine 1 phosphate. They regulate many cellular processes, including enzyme activities, cell migration and adhesion, inflammation, and immunity. Cholesterol is metabolized into hydroxycholesterols and 7-ketocholesterol, which not only disrupts membrane fluidity, but also promotes inflammation, oxidative stress, and apoptosis. These processes lead to cellular damage.

Dexamethasone and azithromycin enhance goat sperm preservation quality by regulating lipid metabolism

Phospholipase A (PLA) in goat semen aggregates with egg yolk in semen diluent, leading to sperm death. The aim of this study is to address the issue of sperm death caused by the interaction between PLA and egg yolk, and to explore the protective effect and metabolic regulation mechanism of the combination of dexamethasone (DXMS) and azithromycin (AZM) on goat sperm under low temperature conditions. At a low temperature of 4°C, different concentrations of DXMS were added to semen diluents containing 30μg/mL AZM to detect the quality of goat sperm. The optimal concentration of DXMS was determined to be 20μg/mL. On the 5th day of storage, antioxidant capacity, total cholesterol (TC) levels, energy metabolism, and metabolomics analysis were performed on the sperm of the 20μg/mL DXMS group. The results showed that there was no aggregation caused by the interaction between PLA and egg yolk in the group containing 30μg/mL AZM at 4°C. 20 μg/mL DXMS significantly improved sperm motility, plasma membrane integrity, acrosome integrity, glutathione peroxidase (GPX) (P<0.05), catalase (CAT) (P<0.01), and superoxide dismutase (SOD) activity (P<0.01). The content of reactive oxygen species (ROS) and Fe2+ significantly decreased (P<0.01), while the content of ATP (P<0.01) and TC (P<0.05) significantly increased. Through metabolomics analysis, a total of 56 differential metabolites (P<0.05) were screened, including 5a, 6-Anhydrotetracycline, Betamethasone, and 11-Dehydrocorticosterone, mainly enriched in 8 metabolic pathways (P<0.05), including steroid hormone biosynthesis, glycerophospholipid metabolism, and choline metabolism in cancer. Among them, 5 metabolic pathways are related to lipid metabolism. The results indicate that AZM effectively inhibits the aggregation of PLA and yolk, and the combination of AZM and DXMS enhances the preservation quality of goat sperm during low-temperature preservation by regulating lipid metabolism.

The Inhibitory Potentials of the Root Extract and Fractions of Brenania brieyi (De Wild) (Rubiaceae) on Lactate Dehydrogenase, Phospholipase A2, and α- Amylase in Plasmodium falciparum - Infected Persons

Medicinal plants have been used as an alternative in malaria chemotherapy. This study aimed to determine the in vitro inhibitory potentials of the extract and fractions of Brenania brieyi on Lactate Dehydrogenase (LdH), Phospholipase A2 (PLA2), and α-Amylase enzyme extracted from Plasmodium falciparum. Cold maceration and Liquid-Liquid partitioning were used to obtain the extract and fractions respectively, using different solvent of varying polarity. Phytochemical analysis was done using Gas Chromatography-Flame Ionization detector (GCFID) method to identify and quantify different phytoconstituents. In vitro enzyme assay (α-Amylase, LdH and PLA2) were performed using standard procedure. The extract contained Alkaloids such as Spartein (5.05 µg/ml), Dihydrocytisine (23.12 µg/ml), Aphyllidine (5.25 µg/ml), Ribalinidine (2.65 µg/ml), Epihedrine (1.91 µg/ml), Saponins such as sapogenin (5.70 µg/ml), Tannins (16.25 µg/ml), Flavonoids such as Kaempferol (4.59 µg/ml), Catechin (5.50 µg/ml), Proanthocyanidin (9.81 µg/ml), Anthocyanin (3.22 µg/ml), Narigenin (3.62 µg/ml), Flavonones (8.73 µg/ml), Steroids (8.58 µg/ml), Polyphenols such as Reservatrol (20.68 µg/ml) and Glycosides such as cardiac glycoside (4.42 µg/ml), Cyanogenic glycosides (17.72 µg/ml) while Terpenoids are absent. The percentage inhibition of the enzyme (PLA2, LdH and α-amylase) at 100 mg/ml of extract showed the highest inhibition (37 %, 0 % and 38.33 %) when compared to controls, while ethyl acetate fraction has the highest inhibition (98 %, 34 % and 92 %) at P ˂ 0.05 at 100 mg/kg respectively. This study justifies the use of ethnomedicinal remedies (B. brieyi) in treating malaria in infected individuals. The study also suggests that the extract and fractions may act through the inhibition of plasmodial enzymes in infected persons.

Evaluation of Albumin Denaturation, and Phospholipase A2 (Pla2) Inhibition, and Phytochemical Composition of Methanol Leaf Extract of Psychotria Vogeliana, Benth (Rubiaceae)

Inflammation is a protective response elicited by physical, chemical, biochemical, and/or microbial assault on the body, which serves to prevent progression/escalation of injury. If the response is sufficient the body continues to operate normally, if the reaction is excessive a disease condition (inflammation) occurs which predisposes to various health disorders. Current treatment of inflammation includes immunosuppressant, steroidal, and nonsteroidal agents. Most of these are known to have sometimes serious side/adverse effects. Natural compounds from plants known to have pharmacological activities, including anti-inflammatory and are being used as alternatives. This study aimed to investigate the phytochemical composition and anti-inflammatory properties of the methanol leaf extract of Psychotria vogeliana. Acute toxicity study was conducted following the OECD guidelines 423 Annex 2C. Anti-inflammatory activity was evaluated using albumin denaturation, and phospholipase A2 (PLA2) inhibition assay. Phytochemical analysis was conducted using spectrophotometric methods, and GC-FID. The LD50 of the extract is more than 5000 mg/kg. The extract contained bioactive compounds such as catechin, epicateechin, resvesterol, rutin, narigenin, kaempferol, flavonones, tannins, steroids and anthocynins. Anti-inflammatory evaluation showed activity comparable to that of diclofenac. Possible mechanism of action was identified as Phospholipase A2 (PLA2) inhibition. The use of Psychotria vogeliana in traditional medicine for the management and treatment of inflammatory disorders is therefore justified.

Genotypes of carboxypeptidase A1 and gamma-glutamyltransferase 1 may be useful tools for the diagnosis and the predictor of worrisome features of intraductal papillary mucinous neoplasm in Japan.

This study aimed to clarify whether several single-nucleotide polymorphisms (SNPs)-related chronic pancreatitis such as carboxypeptidase A1 (CPA1), carboxypeptidase B1 (CPB1), Gamma-glutamyltransferase 1 (GGT1), G-protein-coupled receptor Class C Group 6 Member A (GPRC6A), and serine protease inhibitor, Kazal type 1 (SPINK-1) genotypes were associated with clinical characteristics of patients with intraductal papillary mucinous neoplasm (IPMN) and worrisome features of IPMN. We enrolled 100 patients with IPMN and 116 patients as a control. Serum p-amylase, lipase, trypsin, phospholipase A2 (PLA2), and elastase-1 levels were measured. An Olympus EUS (GF-UCT 260) was used to perform endosonography in 100 patients with IPMN. Total EUS score was evaluated using endosonography. DNA was isolated from the duodenal tissue using a commercial system and polymerase chain reaction (PCR) was performed on 7500 Fast PCR System. There were no associations between glucose tolerances, lipid levels and genotypes of CPA1, GGT1, GPRC6A, and SPINK-1 in patients with IPMN. CPA1 genotype was significantly associated with the pathophysiology of IPMN. Then, GGT1 genotype was also significantly associated with EUS total score and the size of cyst more than 20 mm and more than 30 mm as one of worrisome features of IPMN. Genotypes of carboxypeptidase A1 and gamma-glutamyltransferase 1 may be useful tools for the diagnosis and the predictor of worrisome features of IPMN.

Progesterone induces meiosis through two obligate co-receptors with PLA2 activity.

The steroid hormone progesterone (P4) regulates multiple aspects of reproductive and metabolic physiology. Classical P4 signaling operates through nuclear receptors that regulate transcription. In addition, P4 signals through membrane P4 receptors (mPRs) in a rapid nongenomic modality. Despite the established physiological importance of P4 nongenomic signaling, the details of its signal transduction cascade remain elusive. Here, using Xenopus oocyte maturation as a well-established physiological readout of nongenomic P4 signaling, we identify the lipid hydrolase ABHD2 (α/β hydrolase domain-containing protein 2) as an essential mPRβ co-receptor to trigger meiosis. We show using functional assays coupled to unbiased and targeted cell-based lipidomics that ABHD2 possesses a phospholipase A2 (PLA2) activity that requires mPRβ. This PLA2 activity bifurcates P4 signaling by inducing clathrin-dependent endocytosis of mPRβ, resulting in the production of lipid messengers that are G-protein coupled receptors agonists. Therefore, P4 drives meiosis by inducing an ABHD2 PLA2 activity that requires both mPRβ and ABHD2 as obligate co-receptors.