Conjugation with the Carrier Helped to Reveal acidification-Induced Structural Shift in the Peptide from Phospholipase Domain of Parvovirus B19.

Spectroscopic studies on domains and peptides of large proteins are complicated because of the tendency of short peptides to form oligomers in aquatic buffers, but conjugation of a peptide with a carrier protein may be helpful. In this study we approved that a fragment of SK30 peptide from phospholipase A2 domain of VP1 Parvovirus B19 capsid protein (residues: 144-159; 164; 171-183; sequence: SAVDSAARIHDFRYSQLAKLGINPYTHWTVADEELLKNIK) turns from random coil to alpha helix in the acidic medium only in case if it had been conjugated with BSA (through additional N-terminal Cys residue, turning it into CSK31 peptide, and SMCC linker) according to CD-spectroscopy results. In contrast, unconjugated SK30 peptide does not undergo such shift because it forms stable oligomers connected by intermolecular antiparallel beta sheet, according to IR-spectroscopy, CD-spectroscopy, blue native gel electrophoresis and centrifugal ultrafiltration, as, probably, the whole isolated phospholipase domain of VP1 protein does. However, being a part of the long VP1 capsid protein, phospholipase domain may change its fold during the acidification of the medium in the endolysosome by the way of the formation of contacts between protonated His153 and Asp175, promoting the shift from random coil to alpha helix in its N-terminal part. This study opens up a perspective of vaccine development, since rabbit polyclonal antibodies against the conjugate of CSK31 peptide with BSA, in which the structure of the second alpha helix from the phospholipase A2 domain should be reproduced, can bind epitopes of the complete recombinant unique part of VP1 Parvovirus B19 capsid (residues: 1-227).

Intron retention in PI-PLC γ1 mRNA as a key mechanism affecting MMP expression in human primary fibroblast-like synovial cells.

The intron retention (IR) is a phenomenon utilized by cells to allow diverse fates at the same mRNA, leading to a different pattern of synthesis of the same protein. In this study, we analyzed the modulation of phosphoinositide-specific phospholipase C (PI-PLC) enzymes by Harpagophytum procumbens extract (HPE) in synoviocytes from joins of osteoarthritis (OA) patients. In some samples, the PI-PLC γ1 isoform mature mRNA showed the IR and, in these synoviocytes, the HPE treatment increased the phenomenon. Moreover, we highlighted that as a consequence of IR, a lower amount of PI-PLC γ1 was produced. The decrease of PI-PLC γ1 was associated with the decrease of metalloprotease-3 (MMP-3), and MMP-13, and ADAMTS-5 after HPE treatment. The altered expression of MMPs is a hallmark of the onset and progression of OA, thus substances able to decrease their expression are very desirable. The interesting outcomes of this study are that 35% of analyzed synovial tissues showed the IR phenomenon in the PI-PLC γ1 mRNA and that the HPE treatment increased this phenomenon. For the first time, we found that the decrease of PI-PLC γ1 protein in synoviocytes interferes with MMP production, thus affecting the pathways involved in the MMP expression. This finding was validated by the silencing of PI-PLC γ1 in synoviocytes where the IR phenomenon was not present. Our results shed new light on the biochemical mechanisms involved in the degrading enzyme production in the joint of OA patients, suggesting a new therapeutic target and highlighting the importance of personalized medicine.

The correlation between anti-phospholipase A2 receptor antibodies and hypercoagulability in patients with idiopathic membranous nephropathy.

BACKGROUND: Patients with idiopathic membranous nephropathy (IMN) are more likely to be complicated by venous thromboembolism (VTE). The aim of the study was to investigate the potential association between anti-phospholipase A2 receptor (PLA2R) antibodies and hypercoagulability in patients with IMN. METHODS: A total of 168 patients with biopsy-proven IMN and 36 patients with biopsy-proven minimal change disease (MCD) were enrolled in this study. The clinical data, serum anti-PLA2R antibodies and coagulation-related indices of the patients were retrospectively analyzed. RESULTS: Patients with IMN were categorized into glomerular PLA2R staining-positive (GAg+) IMN group and glomerular PLA2R staining-negative (GAg-) IMN group in the study. Patients with IMN who were GAg + had lower PT, APTT and R time than patients with IMN who were GAg-, while the CI value was higher in patients with IMN who were GAg+. Patients with IMN who were GAg + were divided into the SAb+/GAg + group and the SAb-/GAg + group. Patients with IMN who were SAb+/GAg + had higher Fib and MA values than patients with IMN who were SAb-/GAg+. Correlation analysis showed that serum anti-PLA2R antibodies were positively correlated with fibrinogen, D-dimer, K time, CI value, α-angle, and MA value. Multiple linear regression analysis indicated that anti-PLA2R antibodies were independently correlated with fibrinogen and MA value. CONCLUSION: Our study provides a new perspective on the underlying mechanisms of hypercoagulability in patients with IMN. Anti-PLA2R antibodies are associated with hypercoagulability in patients with IMN and may affect coagulation in patients with IMN by affecting platelet aggregation function and fibrinogen counts.

Quantitative Monitoring of GPCR-Mediated Spatiotemporal IP3 Dynamics Using Confocal Fluorescence Microscopy.

Activation of G protein-coupled receptors upon chemoattractant stimulation induces activation of multiple signaling pathways. To fully understand how these signaling pathway coordinates to achieve directional migration of neutrophils, it is essential to determine the dynamics of the spatiotemporal activation profile of signaling components at the level of single living cells. Here, we describe a detailed methodology for monitoring and quantitatively analyzing the spatiotemporal dynamics of 1,4,5-inositol trisphosphate (IP3) in neutrophil-like HL60 cells in response to various chemoattractant fields by applying Förster resonance energy transfer (FRET) fluorescence microscopy.

Lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells is inhibited by microRNA-494-3p via targeting lipoprotein-associated phospholipase A2.

BACKGROUND: Gram-negative bacterial lipopolysaccharide (LPS) is a major component of inflammation and plays a key role in the pathogenesis of sepsis. According to our previous study, the expression of lipoprotein-associated phospholipase A2 (Lp-PLA2) is significantly upregulated in septic patients and is positively correlated with the severity of this disease. Herein, we investigated the potential roles of Lp-PLA2-targeting microRNAs (miRNAs) in LPS-induced inflammation in murine mononuclear macrophages (RAW264.7 cells). METHODS: In LPS-stimulated RAW264.7 cells, Lp-PLA2 was confirmed to be expressed during the inflammatory response. The function of microRNA-494-3p (miR-494-3p) in the LPS-induced inflammatory response of RAW264.7 cells was determined by the transfection of a miR-494-3p mimic or inhibitor in vitro. RESULTS: Compared to the control, LPS induced a significant increase in the Lp-PLA2 level, which was accompanied by the release of inflammatory mediators. The bioinformatics and qRT‒PCR results indicated that the miR-494-3p level was associated with Lp-PLA2 expression in the LPS-induced inflammatory response of RAW264.7 cells. Dual-luciferase reporter assay results confirmed that the 3'-UTR of Lp-PLA2 was a functional target of microRNA-494-3p. During the LPS-induced inflammatory response of RAW264.7 cells, targeting Lp-PLA2 and transfecting miR-494-3p mimics significantly upregulated the expression of miR-494-3p, leading to a reduction in the release of inflammatory factors and conferring a protective effect on LPS-stimulated RAW264.7 cells. CONCLUSION: By targeting Lp-PLA2, miR-494-3p suppresses Lp-PLA2 secretion, thereby alleviating LPS-induced inflammation, which indicates that miR-494-3p may be a potential target for sepsis treatment.

Correlation between lipoprotein-associated phospholipase A2 and poststroke mild cognitive impairment.

OBJECTIVES: This study aimed to investigate the correlation between serum lipoprotein-associated phospholipase A2 (Lp-PLA2) and poststroke mild cognitive impairment (PSMCI). METHODS: The patients included in the study were divided into PSMCI (68 cases) and cognitively normal (CN) (218 cases) groups and followed up for six months. Demographic and clinical data were collected. A logistic regression analysis was performed to determine whether Lp-PLA2 is an independent risk factor for PSMCI. Spearman's correlation analysis was used to examine the correlation between Lp-PLA2 levels and Montreal Cognitive Assessment (MoCA) scores. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic threshold value of Lp-PLA2 for PSMCI. RESULTS: Serum Lp-PLA2 levels were significantly higher in the PSMCI group than in the CN group. The logistic regression analysis showed that Lp-PLA2 was an independent risk factor for PSMCI (OR = 1.05, 95% CI = 1.03-1.07). Spearman's correlation analysis revealed a significant correlation between the Lp-PLA2 levels and MoCA scores (R = -0.49). The area under the ROC curve for Lp-PLA2 was 0.849, and the threshold value for PSMCI occurrence was 236.8 ng/ml. CONCLUSIONS: Elevated serum Lp-PLA2 is an independent risk factor for PSMCI and may serve as a potential biomarker for PSMCI.

Exploring selection signatures in the divergence and evolution of lipid droplet (LD) associated genes in major oilseed crops.

BACKGROUND: Oil bodies or lipid droplets (LDs) in the cytosol are the subcellular storage compartments of seeds and the sites of lipid metabolism providing energy to the germinating seeds. Major LD-associated proteins are lipoxygenases, phospholipaseD, oleosins, TAG-lipases, steroleosins, caleosins and SEIPINs; involved in facilitating germination and enhancing peroxidation resulting in off-flavours. However, how natural selection is balancing contradictory processes in lipid-rich seeds remains evasive. The present study was aimed at the prediction of selection signatures among orthologous clades in major oilseeds and the correlation of selection effect with gene expression. RESULTS: The LD-associated genes from the major oil-bearing crops were analyzed to predict natural selection signatures in phylogenetically close-knit ortholog clusters to understand adaptive evolution. Positive selection was the major force driving the evolution and diversification of orthologs in a lineage-specific manner. Significant positive selection effects were found in 94 genes particularly in oleosin and TAG-lipases, purifying with excess of non-synonymous substitution in 44 genes while 35 genes were neutral to selection effects. No significant selection impact was noticed in Brassicaceae as against LOX genes of oil palm. A heavy load of deleterious mutations affecting selection signatures was detected in T-lineage oleosins and LOX genes of Arachis hypogaea. The T-lineage oleosin genes were involved in mainly anther, tapetum and anther wall morphogenesis. In Ricinus communis and Sesamum indicum > 85% of PLD genes were under selection whereas selection pressures were low in Brassica juncea and Helianthus annuus. Steroleosin, caleosin and SEIPINs with large roles in lipid droplet organization expressed mostly in seeds and were under considerable positive selection pressures. Expression divergence was evident among paralogs and homeologs with one gene attaining functional superiority compared to the other. The LOX gene Glyma.13g347500 associated with off-flavor was not expressed during germination, rather its paralog Glyma.13g347600 showed expression in Glycine max. PLD-α genes were expressed on all the tissues except the seed,δ genes in seed and meristem while ß and γ genes expressed in the leaf. CONCLUSIONS: The genes involved in seed germination and lipid metabolism were under strong positive selection, although species differences were discernable. The present study identifies suitable candidate genes enhancing seed oil content and germination wherein directional selection can become more fruitful.

Secretory Phospholipase A2 Levels Are High in Women with Sickle Cell Disease and Menstruation-Induced Vaso-Occlusive Crises.

Menstruation-induced vaso-occlusive crisis (MIVOC) is a significant cause of morbidity in women with sickle cell disease (SCD). Secretory phospholipase A2 (sPLA2) is an inflammatory biomarker that is elevated in vaso-occlusive events such as acute chest syndrome (ACS), but its role in MIVOC is not previously studied. This study compared the serum level of sPLA2 among women with MIVOC and those without MIVOC. This is a comparative cross-sectional study. 354 women with SCD were screened for MIVOC using a structured questionnaire. sPLA2 levels were assayed using a standard ELISA while full blood counts were performed on an automated hematology analyzer. Data were analyzed using the SPSS software v26.0. Results were summarized as frequencies, percentages, and mean ± standard deviation. Variables were compared using the Student's t-test and Pearson's correlation. A p-value of <.05 was considered significant. The prevalence of MIVOC was 26.8%. Participants with MIVOC (n = 95) had significantly lower mean hemoglobin concentration (8.00 ± 2.03g/dL vs. 9.95 ± 4.15g/dL, p < .000), significantly higher mean platelets count (518.71 ± 84.58 × 109/L vs 322.21 ± 63.80 × 109/L, p < .000) and higher sPLA2 level (6.58 ± 1.94 IU vs 6.03 ± 0.42 IU, p = .008) compared to those without MIVOC (n = 95). Among participants with MIVOC, sPLA2 levels positively correlated with total white blood cell, absolute neutrophil, and lymphocyte counts. This study demonstrates that MIVOC is common among women with SCD and that the pathophysiology of MIVOC may have an inflammatory basis similar to that of ACS. The potential role of anti-inflammatory and antiplatelet agents in preventing and treating MIVOC may be explored.

Imaging Phospholipase D Activity with Clickable Alcohols via Transphosphatidylation.

Phospholipase D (PLD) is an enzyme with many functions, one of which is the synthesis of phosphatidic acid (PA), a molecule with a myriad of effects on various organ systems and processes. These numerous roles make it hard to understand the true action of PA in cellular and bodily processes. Imaging PLD activity is one way to better understand the synthesis of PA and start to elucidate its function. However, many of the current imaging techniques for PLD come with limitations. This chapter presents a thorough methodology of a new imaging technique for PLD activity with clickable alcohols via transphosphatidylation (IMPACT) and Real-Time IMPACT (RT-IMPACT) that takes advantage of clickable chemistry to overcome current limitations. Using strain-promoted azide-alkyne cycloaddition (SPAAC), inverse electron-demand Diels-Alder (IEDDA), and the synthesis of various organic compounds, this chapter will explain a step-by-step procedure of how to perform the IMPACT and RT-IMPACT method(s).

Contribution of transient receptor potential vanilloid 1 (TRPV1) channel to cholinergic contraction of rat bladder smooth muscle.

Transient receptor potential vanilloid 1 (TRPV1) is a calcium-permeable ion channel that is gated by the pungent constituent of red chili pepper, capsaicin, and by related chemicals from the group of vanilloids, in addition to noxious heat. It is expressed mostly in sensory neurons to act as a detector of painful stimuli produced by pungent chemicals and high temperatures. Although TRPV1 is also found outside the sensory nervous system, its expression and function in the bladder detrusor smooth muscle (DSM) remain controversial. Here, by using Ca2+ imaging and patch clamp on isolated rat DSM cells, in addition to tensiometry on multicellular DSM strips, we show that TRPV1 is expressed functionally in only a fraction of DSM cells, in which it acts as an endoplasmic reticulum Ca2+-release channel responsible for the capsaicin-activated [Ca2+]i rise. Carbachol-stimulated contractions of multicellular DSM strips contain a TRPV1-dependent component, which is negligible in the circular DSM but reaches ≤50% in the longitudinal DSM. Activation of TRPV1 in rat DSM during muscarinic cholinergic stimulation is ensured by phospholipase A2-catalysed derivation of arachidonic acid and its conversion by lipoxygenases to eicosanoids, which act as endogenous TRPV1 agonists. Immunofluorescence detection of TRPV1 protein in bladder sections and isolated DSM cells confirmed both its preferential expression in the longitudinal DSM sublayer and its targeting to the endoplasmic reticulum. We conclude that TRPV1 is an essential contributor to the cholinergic contraction of bladder longitudinal DSM, which might be important for producing spatial and/or temporal anisotropy of bladder wall deformation in different regions during parasympathetic stimulation. KEY POINTS: The transient receptor potential vanilloid 1 (TRPV1) heat/capsaicin receptor/channel is localized in the endoplasmic reticulum membrane of detrusor smooth muscle (DSM) cells of the rat bladder, operating as a calcium-release channel. Isolated DSM cells are separated into two nearly equal groups, within which the cells either show or do not show TRPV1-dependent [Ca2+]i rise. Carbachol-stimulated, muscarinic ACh receptor-mediated contractions of multicellular DSM strips contain a TRPV1-dependent component. This component is negligible in the circular DSM but reaches ≤50% in longitudinal DSM. Activation of TRPV1 in rat DSM during cholinergic stimulation involves phospholipase A2-catalysed derivation of arachidonic acid and its conversion by lipoxygenases to eicosanoids, which act as endogenous TRPV1 agonists.

The joint association of lipoprotein(a) and Lp-PLA2 with the risk of stroke recurrence.

BACKGROUND AND PURPOSE: Currently little is known about the joint association of lipoprotein (a) [Lp(a)] and Lipoprotein-associated phospholipase A2 (Lp-PLA2) with stroke recurrence. METHODS: In this prospective multicenter cohort study, 10,675 consecutive acute ischemic stroke (IS) and transient ischemic attack patients (TIA) with Lp(a) and Lp-PLA2 were enrolled. The association of stroke recurrence within 1 year with Lp(a) and Lp-PLA2 was assessed using Cox proportional hazards models and Kaplan-Meier curves. The interaction between Lp(a) and Lp-PLA2 with stroke recurrence was evaluated by multiplicative and additive scales. RESULTS: A significant joint association of Lp(a) and Lp-PLA2 with the risk of stroke recurrence was observed. Multivariate cox regression analysis demonstrated that the combination of elevated Lp(a) (≥ 50 mg/dL) and Lp-PLA2 (≥175.1 ng/ml) was independently associated with the risk of stroke recurrence (adjusted hazard ratio: 1.42; 95 % CI: 1.15-1.76). Both significant multiplicative [(exp(ß3):1.63, 95 % CI: 1.17-2.29, P = 0.004] and additive interaction (RERI:0.55, 95 % CI: 0.20-0.90, P = 0.002; AP: 0.39, 95 %CI, 0.24-0.53) were observed between Lp(a) and Lp-PLA2. CONCLUSIONS: Our results indicated that Lp(a) and Lp-PLA2 have a joint association with the risk of stroke recurrence in IS/TIA patients. Patients with concomitant presence of elevated Lp(a) and Lp-PLA2 have greater risk of stroke recurrence.

Essential trace element and phosphatidylcholine remodeling: Implications for body composition and insulin resistance.

BACKGROUND: Recent studies indicated that bioactive lipids of phosphatidylcholines (PCs) and lysophosphatidylcholines (LysoPCs) predict unhealthy metabolic phenotypes, but results remain inconsistent. To fill this knowledge gap, we investigated whether essential trace elements affect PC-Lyso PC remodeling pathways and the risk of insulin resistance (IR). METHODS: Anthropometric and blood biochemical data (glucose, insulin, and lipoprotein-associated phospholipase A2 (Lp-PLA2)) were obtained from 99 adults. Blood essential/probably essential trace elements and lipid metabolites were respectively measured by inductively coupled plasma mass spectrometry (ICP-MS), and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). RESULT AND CONCLUSION: Except for LysoPC (O-18:0/0:0), an inverse V shape was observed between body weight and PC and LysoPC species. A Pearson correlation analysis showed that essential/probably-essential metals (Se, Cu, and Ni: r=-0.4∼-0.7) were negatively correlated with PC metabolites but positively correlated with LysoPC (O-18:0/0:0) (Se, Cu, and Ni: r=0.85-0.64). Quantile-g computation showed that one quantile increase in essential metals was associated with a 2.16-fold increase in serum Lp-PLA2 (ß=2.16 (95 % confidence interval (CI): 0.34, 3.98), p=0.023), which are key enzymes involved in PC/Lyso PC metabolism. An interactive analysis showed that compared to those with the lowest levels (reference), individuals with the highest levels of serum PCs (pooled, M2) and the lowest essential/probably essential metals (M1) were associated with a healthier body composition and had a 76 % decreased risk of IR (odds ratio (OR)=0.24 (95 % CI: 0.06, 0.90), p<0.05). In contrast, increased exposure to LysoPC(O-18:0/0:0) (M2) and essential metals (M2) exhibited an 8.22-times highest risk of IR (OR= 8.22 (2.07, 32.57), p<0.05) as well as an altered body composition. In conclusion, overexposure to essential/probably essential trace elements may promote an unhealthy body weight and IR through modulating PC/LysoPC remodeling pathways.

Phospholipid Signaling in Crop Plants: A Field to Explore.

In plant models such as Arabidopsis thaliana, phosphatidic acid (PA), a key molecule of lipid signaling, was shown not only to be involved in stress responses, but also in plant development and nutrition. In this article, we highlight lipid signaling existing in crop species. Based on open access databases, we update the list of sequences encoding phospholipases D, phosphoinositide-dependent phospholipases C, and diacylglycerol-kinases, enzymes that lead to the production of PA. We show that structural features of these enzymes from model plants are conserved in equivalent proteins from selected crop species. We then present an in-depth discussion of the structural characteristics of these proteins before focusing on PA binding proteins. For the purpose of this article, we consider RESPIRATORY BURST OXIDASE HOMOLOGUEs (RBOHs), the most documented PA target proteins. Finally, we present pioneering experiments that show, by different approaches such as monitoring of gene expression, use of pharmacological agents, ectopic over-expression of genes, and the creation of silenced mutants, that lipid signaling plays major roles in crop species. Finally, we present major open questions that require attention since we have only a perception of the peak of the iceberg when it comes to the exciting field of phospholipid signaling in plants.

Cardiolipin in myocardial ischaemia-reperfusion injury: From molecular mechanisms to clinical strategies.

Myocardial reperfusion injury occurs when blood flow is restored after ischemia, an essential process to salvage ischemic tissue. However, this phenomenon is intricate, characterized by various harmful effects. Tissue damage in ischemia-reperfusion injury arises from various factors, including the production of reactive oxygen species, the sequestration of proinflammatory immune cells in ischemic tissues, the induction of endoplasmic reticulum stress, and the occurrence of postischemic capillary no-reflow. Secretory phospholipase A2 (sPLA2) plays a crucial role in the eicosanoid pathway by releasing free arachidonic acid from membrane phospholipids' sn-2 position. This liberated arachidonic acid serves as a substrate for various eicosanoid biosynthetic enzymes, including cyclooxygenases, lipoxygenases, and cytochromes P450, ultimately resulting in inflammation and an elevated risk of reperfusion injury. Therefore, the activation of sPLA2 directly correlates with the heightened and accelerated damage observed in myocardial ischemia-reperfusion injury (MIRI). Presently, clinical trials are in progress for medications aimed at sPLA2, presenting promising avenues for intervention. Cardiolipin (CL) plays a crucial role in maintaining mitochondrial function, and its alteration is closely linked to mitochondrial dysfunction observed in MIRI. This paper provides a critical analysis of CL modifications concerning mitochondrial dysfunction in MIRI, along with its associated molecular mechanisms. Additionally, it delves into various pharmacological approaches to prevent or alleviate MIRI, whether by directly targeting mitochondrial CL or through indirect means.

Trypanosoma cruzi infection modulates secreted phospholipase A2 expression in the salivary glands of Rhodnius prolixus.

Phospholipases A2 (PLA2) comprise a superfamily of enzymes that specifically catalyze hydrolysis of the ester bond at the sn-2 position of glycerophospholipids, generating lysophospholipids and fatty acids. In Rhodnius prolixus, one of the main vectors of the Chagas's disease etiologic agent Trypanosoma cruzi, it was previously shown that lysophosphatidylcholine, a bioactive lipid, found in the insect's saliva, contributes to the inhibition of platelet aggregation, and increases the production of nitric oxide, an important vasodilator. Due to its role in potentially generating LPC, here we studied the PLA2 present in the salivary glands of R. prolixus. PLA2 activity is approximately 100 times greater in the epithelium than in the contents of salivary glands. Our study reveals the role of the RpPLA2XIIA gene in the insect feeding performance and in the fatty acids composition of phospholipids extracted from the salivary glands. Knockdown of RpPLA2XIIA significantly altered the relative amounts of palmitic, palmitoleic, oleic and linoleic acids. A short-term decrease in the expression of RpPLA2III and RpPLA2XIIA in the salivary glands of R. prolixus was evident on the third day after infection by T. cruzi. Taken together, our results contribute to the understanding of the role of PLA2 in the salivary glands of hematophagous insects and show that the parasite is capable of modulating even tissues that are not colonized by it.

The relationships between biological novel biomarkers Lp-PLA2 and CTRP-3 and CVD in patients with type 2 diabetes mellitus.

BACKGROUND: Cardiovascular disease (CVD) is recognized as a primary and severe comorbidity in patients with type 2 diabetes mellitus (T2DM) and is also identified as a leading cause of mortality within this population. Consequently, the identification of novel biomarkers for the risk stratification and progression of CVD in individuals with T2DM is of critical importance. METHODS: This retrospective cohort study encompassed 979 patients diagnosed with T2DM, of whom 116 experienced CVD events during the follow-up period. Clinical assessments and comprehensive blood laboratory analyses were conducted. Age- and sex-adjusted Cox proportional hazard regression analysis was utilized to evaluate the association between lipoprotein-associated phospholipase A2 (Lp-PLA2), C1q/tumor necrosis factor-related protein 3 (CTRP-3), and the incidence of CVD in T2DM. The diagnostic performance of these biomarkers was assessed through receiver operating characteristic (ROC) curve analysis and the computation of the area under the curve (AUC). RESULTS: Over a median follow-up of 84 months (interquartile range: 42 [32-54] months), both novel inflammatory markers, Lp-PLA2 and CTRP-3, and traditional lipid indices, such as low-density lipoprotein cholesterol and apolipoprotein B, exhibited aberrant expression in the CVD-afflicted subset of the T2DM cohort. Age- and sex-adjusted Cox regression analysis delineated that Lp-PLA2 (hazard ratio [HR] = 1.007 [95% confidence interval {CI}: 1.005-1.009], p < 0.001) and CTRP-3 (HR = 0.943 [95% CI: 0.935-0.954], p < 0.001) were independently associated with the manifestation of CVD in T2DM. ROC curve analysis indicated a substantial predictive capacity for Lp-PLA2 (AUC = 0.81 [95% CI: 0.77-0.85], p < 0.001) and CTRP-3 (AUC = 0.91 [95% CI: 0.89-0.93], p < 0.001) in forecasting CVD occurrence in T2DM. The combined biomarker approach yielded an AUC of 0.94 (95% CI: 0.93-0.96), p < 0.001, indicating enhanced diagnostic accuracy. CONCLUSIONS: The findings suggest that the biomarkers Lp-PLA2 and CTRP-3 are dysregulated in patients with T2DM who develop CVD and that each biomarker is independently associated with the occurrence of CVD. The combined assessment of Lp-PLA2 and CTRP-3 may significantly augment the diagnostic precision for CVD in the T2DM demographic.

Loxosceles amazonica Brown Spider venom: Insights into enzymatic activities, immunorecognition, and novel phospholipase D isoforms.

The Loxosceles genus represents one of the main arachnid genera of medical importance in Brazil. Despite the gravity of Loxosceles-related accidents, just a handful of species are deemed medically important and only a few have undergone comprehensive venom characterization. Loxosceles amazonica is a notable example of a potentially dangerous yet understudied Loxosceles species. While there have been limited reports of accidents involving L. amazonica to date, accidents related to Loxosceles are increasing in the North and Northeast regions of Brazil, where L. amazonica has been reported. In this work, we provide a complementary biochemical and immunological characterization of L. amazonica venom, considering its most relevant enzymatic activities and its immunorecognition and neutralization by current therapeutic antivenoms. Additionally, a cDNA library enriched with phospholipase D (PLD) sequences from L. amazonica venom glands was built and subsequently sequenced. The results showed that L. amazonica venom is well immunorecognised by all the tested antibodies. Its venom also displayed proteolytic, hyaluronidase, and sphingomyelinase activities. These activities were at least partially inhibited by available antivenoms. With cDNA sequencing of PLDs, seven new putative isoforms were identified in the venom of L. amazonica. These results contribute to a better knowledge of the venom content and activities of a synanthropic, yet understudied, Loxosceles species. In vivo assays are essential to confirm the medical relevance of L. amazonica, as well as to assess its true toxic potential and elucidate its related pathophysiology.

Dual therapy with phospholipase and metalloproteinase inhibitors from Sinonatrix annularis alleviated acute kidney and liver injury caused by multiple snake venoms.

Snakebite envenomation often induces acute kidney injury (AKI) and acute liver injury (ALI), leading to augmented injuries and poor rehabilitation. Phospholipase A2 (PLA2) and metalloproteinase (SVMP) present in venom are responsible for the envenomation-associated events. In this study, mice envenomed with Deinagkistrodon acutus, Naja atra, or Agkistrodon halys pallas venom exhibited typical AKI and ALI symptoms, including significantly increased plasma levels of myoglobin, free hemoglobin, uric acid, aspartate aminotransferase, and alanine aminotransferase and upregulated expression of kidney NGAL and KIM-1. These effects were significantly inhibited when the mice were pretreated with natural inhibitors of PLA2 and SVMP isolated from Sinonatrix annularis (SaPLIγ and SaMPI). The inhibitors protected the physiological structural integrity of the renal tubules and glomeruli, alleviating inflammatory infiltration and diffuse hemorrhage in the liver. Furthermore, the dual therapy alleviated oxidative stress and apoptosis in the kidneys and liver by mitigating mitochondrial damage, thereby effectively reducing the lethal effect of snake venom in the inhibitor-treated mouse model. This study showed that dual therapy with inhibitors of metalloproteinase and phospholipase can effectively prevent ALI and AKI caused by snake bites. Our findings suggest that intrinsic inhibitors present in snakes are prospective therapeutic agents for multi-organ injuries caused by snake envenoming.

N-terminal truncated phospholipase A1 accessory protein PlaS from Serratia marcescens alleviates inhibitory on host cell growth and enhances PlaA1 enzymatic activity.

Phospholipase A1 (PLA1) is a kind of specific phospholipid hydrolase widely used in food, medical, textile. However, limitations in its expression and enzymatic activity have prompted the investigation of the phospholipase-assisting protein PlaS. In this study, we elucidate the role of PlaS in enhancing the expression and activity of PlaA1 through N-terminal truncation. Our research demonstrates that truncating the N-terminal region of PlaS effectively overcomes its inhibitory effect on host cells, resulting in improved cell growth and increased protein solubility of the protein. The yeast two-hybrid assay confirms the interaction between PlaA1 and N-terminal truncated PlaS (∆N27 PlaS), highlighting their binding capabilities. Furthermore, in vitro studies using Biacore analysis reveal a concentration-dependent and specific binding between PlaA1 and ∆N27 PlaS, exhibiting high affinity. Molecular docking analysis provides insights into the hydrogen bond interactions between ∆N27 PlaS and PlaA1, identifying key amino acid residues crucial for their binding. Finally, the enzyme activity of PLA1 was boost to 8.4 U/mL by orthogonal test. Study significantly contributes to the understanding of the interaction mechanism between PlaS and PlaA1, offering potential strategies for enhancing PlaA1 activity through protein engineering approaches.

The Prevalence, Characteristics, and Putative Mechanisms of Dual Antigen-Positive Membranous Nephropathy: The Underestimated Condition.

Following the discovery of podocyte phospholipase A2 receptor and thrombospondin type-1 domain-containing 7A, various potential target antigens for membranous nephropathy (MN) have been reported one after another. MN target antigens have now been identified in a significant proportion of patients, and a new classification framework classifies patients with MN based on the detected antigen and associated disease phenotype. A serology-based approach that does not require a histological diagnosis for patients suspected of having MN has also been proposed. However, there have been cases in which dual positivity for MN antigens and/or corresponding antibodies has been shown. Importantly, some of them showed a transition of the affected patient's immune responses to MN antigens, suggesting that serological diagnosis changes depending on the timing of the analysis. In this review, we provide detailed information on these cases and present an overview of our recent understanding of their putative mechanisms involved in these cases. Greater awareness is required to adequately recognize and develop appropriate therapeutic strategies for this condition.