Publications by authors named "Christine Payré"

23 Publications

  • Page 1 of 1

Multi-Autoantibody Signature and Clinical Outcome in Membranous Nephropathy.

Clin J Am Soc Nephrol 2020 Dec 30;15(12):1762-1776. Epub 2020 Nov 30.

University Côte d'Azur, National Centre for Scientific Research, Institute of Molecular and Cellular Pharmacology, Valbonne Sophia Antipolis, Nice, France

Background And Objectives: Patients with membranous nephropathy can have circulating autoantibodies against membrane-bound (phospholipase A2 receptor 1 [PLA2R1] and thrombospondin type-1 domain containing 7A [THSD7A]) and intracellular (aldose reductase, SOD2, and α-enolase) podocyte autoantigens. We studied their combined association with clinical outcomes.

Design, Setting, Participants, & Measurements: Serum levels of anti-PLA2R1, anti-THSD7A, anti-aldose reductase, anti-SOD2, and anti-α-enolase autoantibodies were determined in 285 patients at diagnosis and during follow-up using standardized and homemade assays. An eGFR>60 ml/min per 1.73 m and remission of proteinuria (<0.3/<3.5 g per d) after 12 months were the outcomes of interest.

Results: At diagnosis, 182 (64%), eight (3%), and 95 (33%) patients were anti-PLA2R1, anti-THSD7A, and double negative, respectively. The prevalence of a detectable antibody to at least one intracellular antigen was similarly distributed in patients who were anti-PLA2R1 (=118, 65%) and double negative (=64, 67%). Positivity for anti-PLA2R1, anti-SOD2, and anti-α-enolase antibodies and higher titers at diagnosis were associated with poor clinical outcome independently to each other. Combined positivity for anti-PLA2R1, anti-SOD2, and anti-α-enolase was associated with highest risk of poor outcome (odds ratio, 5.5; 95% confidence interval, 1.2 to 24; =0.01). In Kaplan-Meier analysis, patients who were anti-PLA2R1/anti-SOD2 or anti-PLA2R1/anti-α-enolase had lower eGFR at 12 months compared with patients who were anti-PLA2R1/anti-SOD2 or anti-α-enolase. Predictive tests (net reclassification index and area under the curve-receiver-operating characteristic analysis) showed that combined assessment of antibodies improved classification of outcome in 22%-34% of cases for partial remission of proteinuria and maintenance of normal eGFR. For patients with nephrotic syndrome at diagnosis, anti-SOD2 positivity and high anti-PLA2R1 titer were associated with a lack of complete remission. Patients who were anti-PLA2R1/anti-intracellular antigens had the lowest proteinuria and the highest eGFR at diagnosis and the lowest risk of lower eGFR at 12 months. Epitope spreading was present in 81% of patients who were anti-PLA2R1 and was associated with increased positivity for intracellular antigens and poor eGFR at diagnosis and 12 months.

Conclusions: Combined serological analysis of autoantibodies targeting membrane-bound and intracellular autoantigens identifies patients with poor clinical outcomes.
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http://dx.doi.org/10.2215/CJN.02500220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769033PMC
December 2020

Surfactant-secreted phospholipase A interplay and respiratory outcome in preterm neonates.

Am J Physiol Lung Cell Mol Physiol 2020 07 13;319(1):L95-L104. Epub 2020 May 13.

Cystic fibrosis and Bronchial diseases team-INSERM U938, Institut Pasteur, Paris, France.

Secreted phospholipase A hydrolyzes surfactant phospholipids and is crucial for the inflammatory cascade; preterm neonates are treated with exogenous surfactant, but the interaction between surfactant and phospholipase is unknown. We hypothesize that this interplay is complex and the enzyme plays a relevant role in neonates needing surfactant replacement. We aimed to: ) identify phospholipases A isoforms expressed in preterm lung; ) study the enzyme role on surfactant retreatment and function and the effect of exogenous surfactant on the enzyme system; and ) verify whether phospholipase A is linked to respiratory outcomes. In bronchoalveolar lavages of preterm neonates, we measured enzyme activity (alone or with inhibitors), enzyme subtypes, surfactant protein-A, and inflammatory mediators. Surfactant function and phospholipid profile were also tested. Urea ratio was used to obtain epithelial lining fluid concentrations. Follow-up data were prospectively collected. Subtype-IIA is the main phospholipase isoform in preterm lung, although subtype-IB may be significantly expressed. Neonates needing surfactant retreatment have higher enzyme activity ( = 0.021) and inflammatory mediators ( always ≤ 0.001) and lower amounts of phospholipids ( always < 0.05). Enzyme activity was inversely correlated to surfactant adsorption (ρ = -0.6; = 0.008; adjusted = 0.009), total phospholipids (ρ = -0.475; = 0.05), and phosphatidylcholine (ρ = -0.622; = 0.017). Exogenous surfactant significantly reduced global phospholipase activity ( < 0.001) and subtype-IIA ( = 0.005) and increased dioleoylphosphatidylglycerol ( < 0.001) and surfactant adsorption ( < 0.001). Enzyme activity correlated with duration of ventilation (ρ = 0.679, = 0.005; adjusted = 0.04) and respiratory morbidity score at 12 mo postnatal age (τ = 0.349, = 0.037; adjusted = 0.043) but was not associated with mortality, bronchopulmonary dysplasia, or other long-term respiratory outcomes.
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http://dx.doi.org/10.1152/ajplung.00462.2019DOI Listing
July 2020

Anti-PLA2R1 Antibodies Containing Sera Induce In Vitro Cytotoxicity Mediated by Complement Activation.

J Immunol Res 2019 30;2019:1324804. Epub 2019 Dec 30.

Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275, Valbonne Sophia Antipolis, France.

The phospholipase A2 receptor (PLA2R1) is the major autoantigen in idiopathic membranous nephropathy (MN). However, the pathogenic role of anti-PLA2R1 autoantibodies is unclear. Our aim was to evaluate the in vitro cytotoxicity of anti-PLA2R1 antibodies mediated by complement. Forty-eight patients with PLA2R1-related MN from the prospective cohort SOURIS were included. Anti-PLA2R1 titer, epitope profile, and anti-PLA2R1 IgG subclasses were characterized by ELISA. Cell cytotoxicity was evaluated by immunofluorescence in HEK293 cells overexpressing PLA2R1 incubated with patient or healthy donor sera in the presence or absence of rabbit complement or complement inhibitors. Mean cytotoxicity of anti-PLA2R1 sera for HEK293 cells overexpressing PLA2R1 was 2 ± 2%, which increased to 24 ± 6% after addition of rabbit complement ( < 0.001) ( = 48). GVB-EDTA, which inhibits all complement activation pathways, completely blocked cell cytotoxicity, whereas Mg-EGTA, which only inhibits the classical and lectin pathways, highly decreased suggesting a limited role of the alternative pathway. A higher diversity of IgG subclasses beyond IgG4 and high titer of total IgG anti-PLA2R1 were associated with increased cytotoxicity ( = 0.01 and = 0.03 respectively). In a cohort of 37 patients treated with rituximab, high level of complement-mediated cytotoxicity was associated with less and delayed remission at month 6 after rituximab therapy (5/12 vs. 20/25 ( = 0.03) in 8.5 months ± 4.4 vs. 4.8 ± 4.0 ( = 0.02)). Kaplan-Meier analysis demonstrated that high level of cytotoxicity (≥40%) ( = 0.005), epitope spreading (defined by immunization beyond the immunodominant CysR domain) ( = 0.002), and high titer of anti-PLA2R1 total IgG ( = 0.01) were factors of poor renal prognosis. Anti-PLA2R1 antibodies containing sera can induce in vitro cytotoxicity mediated by complement activation, and the level of cytotoxicity increases with the diversity and the titer of anti-PLA2R1 IgG subclasses. These patients with high level of complement-mediated cytotoxicity could benefit from adjuvant therapy using complement inhibitor associated with rituximab to induce earlier remission and less podocyte injury.
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http://dx.doi.org/10.1155/2019/1324804DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7012209PMC
June 2020

Antimalarial Activity of Human Group IIA Secreted Phospholipase A in Relation to Enzymatic Hydrolysis of Oxidized Lipoproteins.

Infect Immun 2019 11 18;87(11). Epub 2019 Oct 18.

Université Côte d'Azur, CNRS, IPMC, Valbonne Sophia Antipolis, France

The level of human group IIA secreted phospholipase A (hGIIA sPLA) is increased in the plasma of malaria patients, but its role is unknown. In parasite culture with normal plasma, hGIIA is inactive against , contrasting with hGIIF, hGV, and hGX sPLAs, which readily hydrolyze plasma lipoproteins, release nonesterified fatty acids (NEFAs), and inhibit parasite growth. Here, we revisited the anti- activity of hGIIA under conditions closer to those of malaria physiopathology where lipoproteins are oxidized. In parasite culture containing oxidized lipoproteins, hGIIA sPLA was inhibitory, with a 50% inhibitory concentration value of 150.0 ± 40.8 nM, in accordance with its capacity to release NEFAs from oxidized particles. With oxidized lipoproteins, hGIIF, hGV, and hGX sPLAs were also more potent, by 4.6-, 2.1-, and 1.9-fold, respectively. Using specific immunoassays, we found that hGIIA sPLA is increased in plasma from 41 patients with malaria over levels for healthy donors (median [interquartile range], 1.6 [0.7 to 3.4] nM versus 0.0 [0.0 to 0.1] nM, respectively; < 0.0001). Other sPLAs were not detected. Malaria plasma, but not normal plasma, contains oxidized lipoproteins and was inhibitory to when spiked with hGIIA sPLA Injection of recombinant hGIIA into mice infected with reduced the peak of parasitemia, and this was effective only when the level of plasma peroxidation was increased during infection. In conclusion, we propose that malaria-induced oxidation of lipoproteins converts these into a preferential substrate for hGIIA sPLA, promoting its parasite-killing effect. This mechanism may contribute to host defense against in malaria where high levels of hGIIA are observed.
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http://dx.doi.org/10.1128/IAI.00556-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6803347PMC
November 2019

Novel ELISA for thrombospondin type 1 domain-containing 7A autoantibodies in membranous nephropathy.

Kidney Int 2019 03;95(3):666-679

Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, UMR7275 Valbonne Sophia Antipolis, France. Electronic address:

Autoantibodies against phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type 1 domain-containing 7A (THSD7A) are emerging as biomarkers to classify membranous nephropathy (MN) and to predict outcome or response to treatment. Anti-THSD7A autoantibodies are detected by Western blot and indirect immunofluorescence test (IIFT). Here, we developed a sensitive enzyme-linked immunosorbent assay (ELISA) optimized for quantitative detection of anti-THSD7A autoantibodies. Among 1012 biopsy-proven MN patients from 6 cohorts, 28 THSD7A-positive patients were identified by ELISA, indicating a prevalence of 2.8%. By screening additional patients, mostly referred because of PLA2R1-unrelated MN, we identified 21 more cases, establishing a cohort of 49 THSD7A-positive patients. Twenty-eight patients (57%) were male, and male patients were older than female patients (67 versus 49 years). Eight patients had a history of malignancy, but only 3 were diagnosed with malignancy within 2 years of MN diagnosis. We compared the results of ELISA, IIFT, Western blot, and biopsy staining, and found a significant correlation between ELISA and IIFT titers. Anti-THSD7A autoantibodies were predominantly IgG4 in all patients. Eight patients were double positive for THSD7A and PLA2R1. Levels of anti-THSD7A autoantibodies correlated with disease activity and with response to treatment. Patients with high titer at baseline had poor clinical outcome. In a subgroup of patients with serial titers, persistently elevated anti-THSD7A autoantibodies were observed in patients who did not respond to treatment or did not achieve remission. We conclude that the novel anti-THSD7A ELISA can be used to identify patients with THSD7A-associated MN and to monitor autoantibody titers during treatment.
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http://dx.doi.org/10.1016/j.kint.2018.10.024DOI Listing
March 2019

Streptococcal Lancefield polysaccharides are critical cell wall determinants for human Group IIA secreted phospholipase A2 to exert its bactericidal effects.

PLoS Pathog 2018 10 15;14(10):e1007348. Epub 2018 Oct 15.

Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.

Human Group IIA secreted phospholipase A2 (hGIIA) is an acute phase protein with bactericidal activity against Gram-positive bacteria. Infection models in hGIIA transgenic mice have suggested the importance of hGIIA as an innate defense mechanism against the human pathogens Group A Streptococcus (GAS) and Group B Streptococcus (GBS). Compared to other Gram-positive bacteria, GAS is remarkably resistant to hGIIA activity. To identify GAS resistance mechanisms, we exposed a highly saturated GAS M1 transposon library to recombinant hGIIA and compared relative mutant abundance with library input through transposon-sequencing (Tn-seq). Based on transposon prevalence in the output library, we identified nine genes, including dltA and lytR, conferring increased hGIIA susceptibility. In addition, seven genes conferred increased hGIIA resistance, which included two genes, gacH and gacI that are located within the Group A Carbohydrate (GAC) gene cluster. Using GAS 5448 wild-type and the isogenic gacI mutant and gacI-complemented strains, we demonstrate that loss of the GAC N-acetylglucosamine (GlcNAc) side chain in the ΔgacI mutant increases hGIIA resistance approximately 10-fold, a phenotype that is conserved across different GAS serotypes. Increased resistance is associated with delayed penetration of hGIIA through the cell wall. Correspondingly, loss of the Lancefield Group B Carbohydrate (GBC) rendered GBS significantly more resistant to hGIIA-mediated killing. This suggests that the streptococcal Lancefield antigens, which are critical determinants for streptococcal physiology and virulence, are required for the bactericidal enzyme hGIIA to exert its bactericidal function.
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http://dx.doi.org/10.1371/journal.ppat.1007348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6201954PMC
October 2018

Group IIA-Secreted Phospholipase A in Human Serum Kills Commensal but Not Clinical Enterococcus faecium Isolates.

Infect Immun 2018 08 23;86(8). Epub 2018 Jul 23.

Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands.

Human innate immunity employs cellular and humoral mechanisms to facilitate rapid killing of invading bacteria. The direct killing of bacteria by human serum is attributed mainly to the activity of the complement system, which forms pores in Gram-negative bacteria. Although Gram-positive bacteria are considered resistant to killing by serum, we uncover here that normal human serum effectively kills Comparison of a well-characterized collection of commensal and clinical isolates revealed that human serum specifically kills commensal strains isolated from normal gut microbiota but not clinical isolates. Inhibitor studies show that the human group IIA secreted phospholipase A2 (hGIIA), but not complement, is responsible for killing of commensal strains in human normal serum. This is remarkable since the hGIIA concentration in "noninflamed" serum was considered too low to be bactericidal against Gram-positive bacteria. Mechanistic studies showed that serum hGIIA specifically causes permeabilization of commensal membranes. Altogether, we find that a normal concentration of hGIIA in serum effectively kills commensal and that resistance of clinical to hGIIA could have contributed to the ability of these strains to become opportunistic pathogens in hospitalized patients.
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http://dx.doi.org/10.1128/IAI.00180-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6056852PMC
August 2018

Phospholipase A2 Receptor 1 Epitope Spreading at Baseline Predicts Reduced Likelihood of Remission of Membranous Nephropathy.

J Am Soc Nephrol 2018 02 7;29(2):401-408. Epub 2017 Nov 7.

Université Pierre et Marie Curie, Sorbonne Universités, Paris, France;

The phospholipase A2 receptor (PLA2R1) is the major autoantigen in primary membranous nephropathy. Several PLA2R1 epitopes have been characterized, and a retrospective study identified PLA2R1 epitope spreading as a potential indicator of poor prognosis. Here, we analyzed the predictive value of anti-PLA2R1 antibody (PLA2R1-Ab) titers and epitope spreading in a prospective cohort of 58 patients positive for PLA2R1-Ab randomly allocated to rituximab (=29) or antiproteinuric therapy alone (=29). At baseline, the epitope profile (CysR, CysRC1, CysRC7, or CysRC1C7) did not correlate with age, sex, time from diagnosis, proteinuria, or serum albumin, but epitope spreading strongly correlated with PLA2R1-Ab titer (<0.001). Ten (58.8%) of the 17 patients who had epitope spreading at baseline and were treated with rituximab showed reversal of epitope spreading at month 6. In adjusted analysis, epitope spreading at baseline was associated with a decreased remission rate at month 6 (odds ratio, 0.16; 95% confidence interval, 0.04 to 0.72; =0.02) and last follow-up (median, 23 months; odds ratio, 0.14; 95% confidence interval, 0.03 to 0.64; =0.01), independently from age, sex, baseline PLA2R1-Ab level, and treatment group. We propose that epitope spreading at baseline be considered in the decision for early therapeutic intervention in patients with primary membranous nephropathy.
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http://dx.doi.org/10.1681/ASN.2017070734DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791059PMC
February 2018

Secreted Phospholipases A2 Are Intestinal Stem Cell Niche Factors with Distinct Roles in Homeostasis, Inflammation, and Cancer.

Cell Stem Cell 2016 07 9;19(1):38-51. Epub 2016 Jun 9.

Department of Pathology, Erasmus MC Cancer Institute, Rotterdam 3000CA, The Netherlands. Electronic address:

The intestinal stem cell niche provides cues that actively maintain gut homeostasis. Dysregulation of these cues may compromise intestinal regeneration upon tissue insult and/or promote tumor growth. Here, we identify secreted phospholipases A2 (sPLA2s) as stem cell niche factors with context-dependent functions in the digestive tract. We show that group IIA sPLA2, a known genetic modifier of mouse intestinal tumorigenesis, is expressed by Paneth cells in the small intestine, while group X sPLA2 is expressed by Paneth/goblet-like cells in the colon. During homeostasis, group IIA/X sPLA2s inhibit Wnt signaling through intracellular activation of Yap1. However, upon inflammation they are secreted into the intestinal lumen, where they promote prostaglandin synthesis and Wnt signaling. Genetic ablation of both sPLA2s improves recovery from inflammation but increases colon cancer susceptibility due to release of their homeostatic Wnt-inhibitory role. This "trade-off" effect suggests sPLA2s have important functions as genetic modifiers of inflammation and colon cancer.
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http://dx.doi.org/10.1016/j.stem.2016.05.023DOI Listing
July 2016

Epitope Spreading of Autoantibody Response to PLA2R Associates with Poor Prognosis in Membranous Nephropathy.

J Am Soc Nephrol 2016 05 13;27(5):1517-33. Epub 2015 Nov 13.

Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France;

The phospholipase A2 receptor (PLA2R1) is the major autoantigen in idiopathic membranous nephropathy. However, the value of anti-PLA2R1 antibody titers in predicting patient outcomes is unknown. Here, we screened serum samples from 50 patients positive for PLA2R1 for immunoreactivity against a series of PLA2R1 deletion mutants covering the extracellular domains. We identified reactive epitopes in the cysteine-rich (CysR), C-type lectin domain 1 (CTLD1), and C-type lectin domain 7 (CTLD7) domains and confirmed the reactivity with soluble forms of each domain. We then used ELISAs to stratify 69 patients positive for PLA2R1 by serum reactivity to one or more of these domains: CysR (n=23), CysRC1 (n=14), and CysRC1C7 (n=32). Median ELISA titers measured using the full-length PLA2R1 antigens were not statistically different between subgroups. Patients with anti-CysR-restricted activity were younger (P=0.008), had less nephrotic range proteinuria (P=0.02), and exhibited a higher rate of spontaneous remission (P=0.03) and lower rates of renal failure progression (P=0.002) and ESRD (P=0.01) during follow-up. Overall, 31 of 69 patients had poor renal prognosis (urinary protein/creatinine ratio >4 g/g or eGFR<45 ml/min per 1.73 m(2) at end of follow-up). High anti-PLA2R1 activity and epitope spreading beyond the CysR epitope were independent risk factors of poor renal prognosis in multivariable Cox regression analysis. Epitope spreading during follow-up associated with disease worsening (n=3), whereas reverse spreading from a CysRC1C7 profile back to a CysR profile associated with favorable outcome (n=1). We conclude that analysis of the PLA2R1 epitope profile and spreading is a powerful tool for monitoring disease severity and stratifying patients by renal prognosis.
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http://dx.doi.org/10.1681/ASN.2014111061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4849812PMC
May 2016

Cross-reactivity of anti-PLA2R1 autoantibodies to rabbit and mouse PLA2R1 antigens and development of two novel ELISAs with different diagnostic performances in idiopathic membranous nephropathy.

Biochimie 2015 Nov 19;118:104-15. Epub 2015 Aug 19.

Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France. Electronic address:

About 70% of patients with idiopathic membranous nephropathy (iMN) have autoantibodies to the phospholipase A2 receptor PLA2R1. We screened sera from iMN patients for their cross-reactivity to human (h), rabbit (rb) and mouse (m) PLA2R1 by western blot (WB) and antigen-specific ELISAs. All iMN patients recognized hPLA2R1 and rbPLA2R1 by WB, and a rbPLA2R1 ELISA was as sensitive as the standardized hPLA2R1 ELISA to monitor anti-PLA2R1 in patients with active disease or in drug-induced remission. In contrast, only 51% of patients were reactive to mPLA2R1 by WB, and a maximum of 78% were weakly to highly positive in the mPLA2R1 ELISA, suggesting that iMN patients exhibit different subsets of anti-PLA2R1 autoantibodies against epitopes that are shared or not among PLA2R1 orthologs. In a cohort of 41 patients with a mean follow-up of 42 months from anti-PLA2R1 assay, the detection of anti-mPLA2R1 autoantibodies was an independent predictor of clinical outcome in multivariate analysis (p = 0.009), and a ROC curve analysis identified a threshold of 605 RU/mL above which 100% of patients (12 patients) had a poor renal outcome (p < 0.001). A similar threshold could not be defined in hPLA2R1 and rbPLA2R1 ELISAs. We conclude that rbPLA2R1 is an alternative antigen to hPLA2R1 to measure anti-PLA2R1 in active disease while mPLA2R1 is a unique antigen that can detect a subset of anti-PLA2R1 autoantibodies present at high levels (>605 RU/mL) only in iMN patients at risk of poor prognosis, and is thus useful to predict iMN outcome.
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http://dx.doi.org/10.1016/j.biochi.2015.08.007DOI Listing
November 2015

In vitro anti-Plasmodium falciparum properties of the full set of human secreted phospholipases A2.

Infect Immun 2015 Jun 30;83(6):2453-65. Epub 2015 Mar 30.

Muséum National d'Histoire Naturelle, UMR 7245 CNRS/MNHN, MCAM équipe BAMEE, Paris, France

We have previously shown that secreted phospholipases A2 (sPLA2s) from animal venoms inhibit the in vitro development of Plasmodium falciparum, the agent of malaria. In addition, the inflammatory-type human group IIA (hGIIA) sPLA2 circulates at high levels in the serum of malaria patients. However, the role of the different human sPLA2s in host defense against P. falciparum has not been investigated. We show here that 4 out of 10 human sPLA2s, namely, hGX, hGIIF, hGIII, and hGV, exhibit potent in vitro anti-Plasmodium properties with half-maximal inhibitory concentrations (IC50s) of 2.9 ± 2.4, 10.7 ± 2.1, 16.5 ± 9.7, and 94.2 ± 41.9 nM, respectively. Other human sPLA2s, including hGIIA, are inactive. The inhibition is dependent on sPLA2 catalytic activity and primarily due to hydrolysis of plasma lipoproteins from the parasite culture. Accordingly, purified lipoproteins that have been prehydrolyzed by hGX, hGIIF, hGIII, and hGV are more toxic to P. falciparum than native lipoproteins. However, the total enzymatic activities of human sPLA2s on purified lipoproteins or plasma did not reflect their inhibitory activities on P. falciparum. For instance, hGIIF is 9-fold more toxic than hGV but releases a lower quantity of nonesterified fatty acids (NEFAs). Lipidomic analyses of released NEFAs from lipoproteins demonstrate that sPLA2s with anti-Plasmodium properties are those that release polyunsaturated fatty acids (PUFAs), with hGIIF being the most selective enzyme. NEFAs purified from lipoproteins hydrolyzed by hGIIF were more potent at inhibiting P. falciparum than those from hGV, and PUFA-enriched liposomes hydrolyzed by sPLA2s were highly toxic, demonstrating the critical role of PUFAs. The selectivity of sPLA2s toward low- and high-density (LDL and HDL, respectively) lipoproteins and their ability to directly attack parasitized erythrocytes further explain their anti-Plasmodium activity. Together, our findings indicate that 4 human sPLA2s are active against P. falciparum in vitro and pave the way to future investigations on their in vivo contribution in malaria pathophysiology.
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http://dx.doi.org/10.1128/IAI.02474-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4432757PMC
June 2015

Prediction of membranous nephropathy recurrence after transplantation by monitoring of anti-PLA2R1 (M-type phospholipase A2 receptor) autoantibodies: a case series of 15 patients.

Nephrol Dial Transplant 2014 Dec 25;29(12):2334-42. Epub 2014 Jul 25.

Service de Néphrologie, Hôpital Pasteur, Université de Nice-Sophia Antipolis, Nice, France.

Background: The predictive value of anti-M-type phospholipase A2 receptor (PLA2R1) autoantibodies for membranous nephropathy (MN) recurrence after renal transplantation remains controversial.

Methods: Our aim was to monitor anti-PLA2R1 IgG4 activity using a sensitive enzyme-linked immunosorbent assay in 15 kidney transplant recipients with MN, and to test the correlation between antibody titres and MN recurrence.

Results: Five patients never exhibited anti-PLA2R1 antibodies, and one of them relapsed. Ten patients (67%) had IgG4 anti-PLA2R1 antibodies at the time of transplantation and during follow-up. The presence of IgG4 anti-PLA2R1 antibodies at the time of kidney transplantation does not imply MN recurrence (P = 0.600, n = 15). However, a positive IgG4 anti-PLA2R1 activity during follow-up (>Month 6) was a significant risk factor for MN relapse (P = 0.0048, n = 10). Indeed, four patients had persistent IgG4 anti-PLA2R1 activity after transplantation and relapsed. Among them, one was successfully treated with rituximab. Another had persistently high IgG4 anti-PLA2R1 activity and exhibited a histological relapse but no proteinuria while on treatment with renin-angiotensin system inhibitors. In contrast, the six other patients who did not relapse exhibited a decrease of their IgG4 anti-PLA2R1 activity following transplant immunosuppression, including two with proteinuria due to biopsy-proven differential diagnoses. A weak transplant immunosuppressive regimen was also a risk factor of MN recurrence (P = 0.0048, n = 10). Indeed, the six patients who received both an induction therapy and a combined treatment with calcineurin inhibitors/mycophenolate exhibited a decrease of IgG4 anti-PLA2R1 activity and did not relapse, while the four patients who did not receive this strong immunosuppressive treatment association had persistently high IgG4 anti-PLA2R1 activity and relapsed.

Conclusion: The monitoring of IgG4 anti-PLA2R1 titres during follow-up helps to predict MN recurrence, and a strong immunosuppressive treatment of anti-PLA2R1 positive patients may prevent recurrence.
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http://dx.doi.org/10.1093/ndt/gfu252DOI Listing
December 2014

The effect of group X secreted phospholipase A2 on fertilization outcome is specific and not mimicked by other secreted phospholipases A2 or progesterone.

Biochimie 2014 Apr 25;99:88-95. Epub 2013 Nov 25.

Université Joseph Fourier, Grenoble F-38000, France; Laboratoire AGIM, Equipe AGC, CNRS FRE3405, La Tronche F-38700, France. Electronic address:

Mouse group X sPLA2 (mGX) is an acrosomal protein playing an important role in fertilization and controlling acrosome reaction (AR) occurring during capacitation. We demonstrated previously that sperm from mGX knock-out mice had a severely impaired fertilization potential in vitro. We also showed that treatment of wild-type sperm with recombinant mGX during capacitation improved fertilization outcome. This interesting property suggests that sPLA2s could be used to improve fertilization in assisted reproductive technologies (ART). However the molecular mechanism explaining the mGX-dependent enhancing effect on fertilization outcome remains unclear so far. Interestingly, like progesterone (P4), mGX is a very potent activator of AR and the role of mGX-induced AR in fertilization outcome was not evaluated so far. To assess the role of sPLA2-induced AR in IVF, we first tested the potency of 9 mouse and 2 human sPLA2s and P4 to trigger AR of mouse sperm. We then tested the ability of 6 of these molecules (mouse Group IIA, mouse Group IID, mouse Group X, human Group V, human Group X and P4) to improve the yield of 2-cell embryos obtained by IVF in mouse. We showed that in the mouse neither P4 nor any of the other sPLA2s tested were able to mimic the IVF improvement produced by mGX-treatment. These results demonstrate that sPLA2s are not commutable in the context of mouse sperm fertility, indicating that their utilisation in other species, is subjected to the identification of probably unique species-specific active sPLA2.
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http://dx.doi.org/10.1016/j.biochi.2013.11.012DOI Listing
April 2014

Group X secreted phospholipase A(2) induces lipid droplet formation and prolongs breast cancer cell survival.

Mol Cancer 2013 Sep 27;12(1):111. Epub 2013 Sep 27.

Department of Molecular and Biomedical Sciences, JoŽef Stefan Institute, Ljubljana, Slovenia.

Background: Alterations in lipid metabolism are inherent to the metabolic transformations that support tumorigenesis. The relationship between the synthesis, storage and use of lipids and their importance in cancer is poorly understood. The human group X secreted phospholipase A2 (hGX sPLA2) releases fatty acids (FAs) from cell membranes and lipoproteins, but its involvement in the regulation of cellular FA metabolism and cancer is not known.

Results: Here we demonstrate that hGX sPLA2 induces lipid droplet (LD) formation in invasive breast cancer cells, stimulates their proliferation and prevents their death on serum deprivation. The effects of hGX sPLA2 are shown to be dependent on its enzymatic activity, are mimicked by oleic acid and include activation of protein kinase B/Akt, a cell survival signaling kinase. The hGX sPLA2-stimulated LD biogenesis is accompanied by AMP-activated protein kinase (AMPK) activation, up-regulation of FA oxidation enzymes and the LD-coating protein perilipin 2, and suppression of lipogenic gene expression. Prolonged activation of AMPK inhibited hGX sPLA2-induced LD formation, while etomoxir, an inhibitor of FA oxidation, abrogated both LD formation and cell survival. The hGX sPLA2-induced changes in lipid metabolism provide a minimal immediate proliferative advantage during growth under optimal conditions, but they confer to the breast cancer cells a sustained ability to resist apoptosis during nutrient and growth factor limitation.

Conclusion: Our results identify hGX sPLA2 as a novel modulator of lipid metabolism that promotes breast cancer cell growth and survival by stimulating LD formation and FA oxidation.
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http://dx.doi.org/10.1186/1476-4598-12-111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3852912PMC
September 2013

Group X secreted phospholipase A2 limits the development of atherosclerosis in LDL receptor-null mice.

Arterioscler Thromb Vasc Biol 2013 Mar 24;33(3):466-73. Epub 2013 Jan 24.

Inserm U970, Paris Cardiovascular Research Center, Université René Descartes, Paris, France.

Objective: Several secreted phospholipases A2 (sPLA2s), including group IIA, III, V, and X, have been linked to the development of atherosclerosis, which led to the clinical testing of A-002 (varespladib), a broad sPLA2 inhibitor for the treatment of coronary artery disease. Group X sPLA2 (PLA2G10) has the most potent hydrolyzing activity toward phosphatidylcholine and is believed to play a proatherogenic role.

Methods And Results: Here, we show that Ldlr(-/-) mice reconstituted with bone marrow from mouse group X-deficient mice (Pla2g10(-/-)) unexpectedly display a doubling of plaque size compared with Pla2g10(+/+) chimeric mice. Macrophages of Pla2g10(-/-) mice are more susceptible to apoptosis in vitro, which is associated with a 4-fold increase of plaque necrotic core in vivo. In addition, chimeric Pla2g10(-/-) mice show exaggerated T lymphocyte (Th)1 immune response, associated with enhanced T-cell infiltration in atherosclerotic plaques. Interestingly, overexpression of human PLA2G10 in murine bone marrow cells leads to significant reduction of Th1 response and to 50% reduction of lesion size.

Conclusions: PLA2G10 expression in bone marrow cells controls a proatherogenic Th1 response and limits the development of atherosclerosis. The results may provide an explanation for the recently reported inefficacy of A-002 (varespladib) to treat patients with coronary artery disease. Indeed, A-002 is a nonselective sPLA2 inhibitor that inhibits both proatherogenic (groups IIA and V) and antiatherogenic (group X) sPLA2s. Our results suggest that selective targeting of individual sPLA2 enzymes may be a better strategy to treat cardiovascular diseases.
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http://dx.doi.org/10.1161/ATVBAHA.112.300309DOI Listing
March 2013

Absence of inflammatory conditions in human varicose saphenous veins.

Inflamm Res 2013 Mar 13;62(3):299-308. Epub 2012 Dec 13.

INSERM U698, CHU X. Bichat, 46 Rue Huchard, 75018 Paris, France.

Introduction: Varicose veins affect one-third of the adult population in western countries, but their pathogenesis is incompletely characterized. One of the most controversial issues is the role of inflammation. It is well known that inflammation involves an increased expression/activity of inflammatory mediators.

Objective: The aim of this study was to investigate the presence or absence of mediators of inflammation in varicose as compared to healthy veins.

Methods And Results: Using immunohistofluorescence on varicose and healthy veins, we investigated the presence of inflammatory cells. They were not detectable. Venous wall C-reactive protein (CRP), fibrinogen (EIA) and pentraxin-3 (Western blot) content were measured. CRP was significantly lower in varicose veins, but no difference was found for fibrinogen or pentraxin-3 between varicose and healthy veins. No difference was observed for enzymes involved in inflammation and responsible for arachidonic acid metabolism such as the acute phase reactant secreted phospholipase A₂-IIA and cyclooxygenase-2, as determined in varicose and healthy veins by Western blot and real-time qRT-PCR.

Conclusions: Our experiments demonstrate no increase in the presence of mediators of inflammation in varicose as compared to healthy veins, suggesting that inflammation may not be an important contributor to the pathogenesis of varicose veins.
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http://dx.doi.org/10.1007/s00011-012-0578-8DOI Listing
March 2013

Human group X secreted phospholipase A2 induces dendritic cell maturation through lipoprotein-dependent and -independent mechanisms.

Atherosclerosis 2012 Jun 22;222(2):367-74. Epub 2012 Mar 22.

INSERM UMRS 937, Université Pierre et Marie Curie UPMC-Paris 6, Faculté de Médecine Pierre et Marie Curie, 91 Boulevard de l'Hôpital, Paris 75634 Cedex 13, France.

Objective: Increased secreted phospholipase A(2) (sPLA(2)) activity has been documented in several inflammatory disorders. Among sPLA(2)s, the human group X (hGX)-sPLA(2) has the highest catalytic activity towards phosphatidylcholine (PC), the major phospholipid of cell membranes and blood lipoproteins. hGX-sPLA(2) has been detected in human atherosclerotic lesions, indicating that sPLA(2)s are an important link between lipids and inflammation, both involved in atherosclerosis. The presence of dendritic cells (DC), the most potent antigen presenting cells, in atherosclerotic lesions has raised the question about their role in disease progression.

Methods And Results: In this study, we show that hGX-sPLA(2)-treated LDL induces human monocyte-derived DC maturation, resulting in a characteristic mature DC phenotype and enhanced DC ability to activate IFNγ secretion from T cells. hGX-sPLA(2) phospholipolysis of LDL produces high levels of lipid mediators, such as lysophosphatidylcholine (LPC) and free fatty acids (FFAs), which also modulate DC maturation. The major molecular species of LPC containing a palmitic or stearic acid esterified in the sn-1 position induce DC maturation, whereas the FFAs can positively or negatively modulate DC maturation depending on their nature. hGX-sPLA(2) added alone can also activate DC in vitro through the hydrolysis of the DC membrane phospholipids leading, however, to a different cytokine profile secretion pattern than the one observed with hGX-sPLA(2)-phospholipolysed LDL.

Conclusion: hGX-sPLA(2) secreted in inflamed tissues can contribute to local DC maturation, resulting in pro-Th1 cells, through the production of various lipid mediators from hydrolysis of either LDL and/or cell plasma membrane.
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http://dx.doi.org/10.1016/j.atherosclerosis.2012.03.014DOI Listing
June 2012

Group X secreted phospholipase A2 proenzyme is matured by a furin-like proprotein convertase and releases arachidonic acid inside of human HEK293 cells.

J Biol Chem 2011 Oct 30;286(42):36509-21. Epub 2011 Aug 30.

Institut de Pharmacologie Moléculaire et Cellulaire, UMR6097, CNRS et Université de Nice-Sophia-Antipolis, 660 Route des Lucioles, Sophia Antipolis, 06560 Valbonne, France.

Among mammalian secreted phospholipases A(2) (sPLA(2)s), group X sPLA(2) has the most potent hydrolyzing activity toward phosphatidylcholine and is involved in arachidonic acid (AA) release. Group X sPLA(2) is produced as a proenzyme and contains a short propeptide of 11 amino acids ending with a dibasic motif, suggesting cleavage by proprotein convertases. Although the removal of this propeptide is clearly required for enzymatic activity, the cellular location and the protease(s) involved in proenzyme conversion are unknown. Here we have analyzed the maturation of group X sPLA(2) in HEK293 cells, which have been extensively used to analyze sPLA(2)-induced AA release. Using recombinant mouse (PromGX) and human (ProhGX) proenzymes; HEK293 cells transfected with cDNAs coding for full-length ProhGX, PromGX, and propeptide mutants; and various permeable and non-permeable sPLA(2) inhibitors and protease inhibitors, we demonstrate that group X sPLA(2) is mainly converted intracellularly and releases AA before externalization from the cell. Most strikingly, the exogenous proenzyme does not elicit AA release, whereas the transfected proenzyme does elicit AA release in a way insensitive to non-permeable sPLA(2) inhibitors. In transfected cells, a permeable proprotein convertase inhibitor, but not a non-permeable one, prevents group X sPLA(2) maturation and partially blocks AA release. Mutations at the dibasic motif of the propeptide indicate that the last basic residue is required and sufficient for efficient maturation and AA release. All together, these results argue for the intracellular maturation of group X proenzyme in HEK293 cells by a furin-like proprotein convertase, leading to intracellular release of AA during secretion.
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http://dx.doi.org/10.1074/jbc.M111.268540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3196088PMC
October 2011

Group V phospholipase A2 in bone marrow-derived myeloid cells and bronchial epithelial cells promotes bacterial clearance after Escherichia coli pneumonia.

J Biol Chem 2011 Oct 17;286(41):35650-35662. Epub 2011 Aug 17.

Division of Vascular Surgery, Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario M5G 2C4, Canada. Electronic address:

Group V-secreted phospholipase A(2) (GV sPLA(2)) hydrolyzes bacterial phospholipids and initiates eicosanoid biosynthesis. Here, we elucidate the role of GV sPLA(2) in the pathophysiology of Escherichia coli pneumonia. Inflammatory cells and bronchial epithelial cells both express GV sPLA(2) after pulmonary E. coli infection. GV(-/-) mice accumulate fewer polymorphonuclear leukocytes in alveoli, have higher levels of E. coli in bronchoalveolar lavage fluid and lung, and develop respiratory acidosis, more severe hypothermia, and higher IL-6, IL-10, and TNF-α levels than GV(+/+) mice after pulmonary E. coli infection. Eicosanoid levels in bronchoalveolar lavage are similar in GV(+/+) and GV(-/-) mice after lung E. coli infection. In contrast, GV(+/+) mice have higher levels of prostaglandin D(2) (PGD(2)), PGF(2α), and 15-keto-PGE(2) in lung and express higher levels of ICAM-1 and PECAM-1 on pulmonary endothelial cells than GV(-/-) mice after lung infection with E. coli. Selective deletion of GV sPLA(2) in non-myeloid cells impairs leukocyte accumulation after pulmonary E. coli infection, and lack of GV sPLA(2) in either bone marrow-derived myeloid cells or non-myeloid cells attenuates E. coli clearance from the alveolar space and the lung parenchyma. These observations show that GV sPLA(2) in bone marrow-derived myeloid cells as well as non-myeloid cells, which are likely bronchial epithelial cells, participate in the regulation of the innate immune response to pulmonary infection with E. coli.
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http://dx.doi.org/10.1074/jbc.M111.262733DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3195628PMC
October 2011

Group X phospholipase A2 is released during sperm acrosome reaction and controls fertility outcome in mice.

J Clin Invest 2010 May 26;120(5):1415-28. Epub 2010 Apr 26.

Grenoble Institute of Neuroscience, INSERM U836, Grenoble, France.

Ejaculated mammalian sperm must undergo a maturation process called capacitation before they are able to fertilize an egg. Several studies have suggested a role for members of the secreted phospholipase A2 (sPLA2) family in capacitation, acrosome reaction (AR), and fertilization, but the molecular nature of these enzymes and their specific roles have remained elusive. Here, we have demonstrated that mouse group X sPLA2 (mGX) is the major enzyme present in the acrosome of spermatozoa and that it is released in an active form during capacitation through spontaneous AR. mGX-deficient male mice produced smaller litters than wild-type male siblings when crossed with mGX-deficient females. Further analysis revealed that spermatozoa from mGX-deficient mice exhibited lower rates of spontaneous AR and that this was associated with decreased in vitro fertilization (IVF) efficiency due to a drop in the fertilization potential of the sperm and an increased rate of aborted embryos. Treatment of sperm with sPLA2 inhibitors and antibodies specific for mGX blocked spontaneous AR of wild-type sperm and reduced IVF success. Addition of lysophosphatidylcholine, a catalytic product of mGX, overcame these deficiencies. Finally, recombinant mGX triggered AR and improved IVF outcome. Taken together, our results highlight a paracrine role for mGX during capacitation in which the enzyme primes sperm for efficient fertilization and boosts premature AR of a likely phospholipid-damaged sperm subpopulation to eliminate suboptimal sperm from the pool available for fertilization.
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http://dx.doi.org/10.1172/JCI40494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2860919PMC
May 2010

Group X phospholipase A2 stimulates the proliferation of colon cancer cells by producing various lipid mediators.

Mol Pharmacol 2009 Oct 14;76(4):778-90. Epub 2009 Jul 14.

Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia Antipolis et Centre National de la Recherche Scientifique, 06560 Valbonne, France.

Among mammalian secreted phospholipases A2 (sPLA(2)s), the group X enzyme has the most potent hydrolyzing capacity toward phosphatidylcholine, the major phospholipid of cell membrane and lipoproteins. This enzyme has recently been implicated in chronic inflammatory diseases such as atherosclerosis and asthma and may also play a role in colon tumorigenesis. We show here that group X sPLA(2) [mouse (m)GX] is one of the most highly expressed PLA(2) in the mouse colon and that recombinant mouse and human enzymes stimulate proliferation and mitogen-activated protein kinase activation of various colon cell lines, including Colon-26 cancer cells. Among various recombinant sPLA(2)s, mGX is the most potent enzyme to stimulate cell proliferation. Based on the use of sPLA(2) inhibitors, catalytic site mutants, and small interfering RNA silencing of cytosolic PLA(2)alpha and M-type sPLA(2) receptor, we demonstrate that mGX promotes cell proliferation independently of the receptor and via its intrinsic catalytic activity and production of free arachidonic acid and lysophospholipids, which are mitogenic by themselves. mGX can also elicit the production of large amounts of prostaglandin E2 and other eicosanoids from Colon-26 cells, but these lipid mediators do not play a role in mGX-induced cell proliferation because inhibitors of cyclooxygenases and lipoxygenases do not prevent sPLA(2) mitogenic effects. Together, our results indicate that group X sPLA(2) may play an important role in colon tumorigenesis by promoting cancer cell proliferation and releasing various lipid mediators involved in other key events in cancer progression.
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http://dx.doi.org/10.1124/mol.108.053371DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769042PMC
October 2009

The M-type receptor PLA2R regulates senescence through the p53 pathway.

EMBO Rep 2009 Mar 6;10(3):271-7. Epub 2009 Feb 6.

UMR 8161, Institut de Biologie de Lille, CNRS/Universités de Lille 1 et 2/Institut Pasteur de Lille, IFR 142, 59021 Lille, France.

Senescence is a stable proliferative arrest induced by various stresses such as telomere erosion, oncogenic or oxidative stress. Compelling evidence suggests that it acts as a barrier against tumour development. Describing new mechanisms that favour an escape from senescence can thus reveal new insights into tumorigenesis. To identify new genes controlling the senescence programme, we performed a loss-of-function genetic screen in primary human fibroblasts. We report that knockdown of the M-type receptor PLA2R (phospholipase A2 receptor) prevents the onset of replicative senescence and diminishes stress-induced senescence. Interestingly, expression of PLA2R increases during replicative senescence, and its ectopic expression results in premature senescence. We show that PLA2R regulates senescence in a reactive oxygen species-DNA damage-p53-dependent manner. Taken together, our study identifies PLA2R as a potential new tumour suppressor gene crucial in the induction of cellular senescence through the activation of the p53 pathway.
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http://dx.doi.org/10.1038/embor.2008.255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658567PMC
March 2009