Endogenous Morphine Levels Are Increased in Sepsis: A Partial Implication of Neutrophils

BACKGROUND: Mammalian cells synthesize morphine and the respective biosynthetic pathway has been elucidated. Human neutrophils release this alkaloid into the media after exposure to morphine precursors. However, the exact role of endogenous morphine in inflammatory processes remains unclear. We postulate that morphine is released during infection and can be determined in the serum of patients with severe infection such as sepsis. METHODOLOGY: The presence and subcellular immunolocalization of endogenous morphine was investigated by ELISA, mass spectrometry analysis and laser confocal microscopy. Neutrophils were activated with Interleukin-8 (IL-8) or lipopolysaccharide (LPS). Morphine secretion was determined by a morphine-specific ELISA. mu opioid receptor expression was assessed with flow cytometry. Serum morphine concentrations of septic patients were determined with a morphine-specific ELISA and morphine identity was confirmed in human neutrophils and serum of septic patients by mass spectrometry analysis. The effects of the concentration of morphine found in serum of septic patients on LPS-induced release of IL-8 by human neutrophils were tested. PRINCIPAL FINDINGS: We confirmed the presence of morphine in human neutrophil extracts and showed its colocalisation with lactoferrin within the secondary granules of neutrophils. Morphine secretion was quantified in the supernatant of activated human polymorphonuclear neutrophils in the presence and absence of Ca(2+). LPS and IL-8 were able to induce a significant release of morphine only in presence of Ca(2+). LPS treatment increased mu opioid receptor expression on neutrophils. Low concentration of morphine (8 nM) significantly inhibited the release of IL-8 from neutrophils when coincubated with LPS. This effect was reversed by naloxone. Patients with sepsis, severe sepsis and septic shock had significant higher circulating morphine levels compared to patients with systemic inflammatory response syndrome and healthy controls. Mass spectrometry analysis showed that endogenous morphine from serum of patient with sepsis was identical to poppy-derived morphine. CONCLUSIONS: Our results indicate that morphine concentrations are increased significantly in the serum of patients with systemic infection and that morphine is, at least in part, secreted from neutrophils during sepsis. Morphine concentrations equivalent to those found in the serum of septic patients significantly inhibited LPS-induced IL-8 secretion in neutrophils

Characterization by liquid chromatography combined with mass spectrometry of monoclonal anti-IGF-1 receptor antibodies produced in CHO and NS0 cells

7H2HM is a new humanized recombinant monoclonal antibody (MAb) directed against insulin-like growth factor-1 receptor and produced in CHO cells. Homogeneity of intact antibody, reduced light and heavy chains, Fab and Fc fragments were investigated by analytical methods based on mass (SDS-PAGE, SEC), charge (IEF, C-IEX) and hydrophobicity differences (RP-HPLC, HIC) and compared side-by-side with A2CHM, produced in NS0 cells. Primary structures and disulfide bridge pairing were analyzed by microsequencing (Edman degradation), mass spectrometry (MALDI–TOF, ES–TOF) and peptide mapping after enzymatic digestion (Trypsin, endoprotease Lys-C, papain). The light chains demonstrated the expected sequences. The heavy chains yielded post-translational modifications previously reported for other recombinant humanized or human IgG1 such as N-terminal pyroglutamic acid, C-terminal lysine clipping and N-glycosylation for asparagine 297. More surprisingly, two-thirds of the 7H2HM heavy chains were shown to contain an additional 24-amino-acid sequence, corresponding to the translation of an intron located between the variable and the constant domains. Taken together these data suggest that 7H2HM is a mixture of three families of antibodies corresponding (i) to the expected structure (17%; 149 297 Da; 1330 amino acids), (ii) a variant with a translated intron in one heavy chains (33%; 152 878 Da; 1354 amino acids) and (iii) a variant with translated introns in two heavy chains (50%; 154 459 Da; 1378 amino acids), respectively. RP-HPLC is not a commonly used chromatographic method to assess purity of monoclonal antibodies but unlike to SEC and SDS-PAGE, was able to show and to quantify the family of structures present in 7H2HM, which were also identified by peptide mapping, mass spectrometry and microsequencing

Detection of Prion Protein in Urine-Derived Injectable Fertility Products by a Targeted Proteomic Approach

BACKGROUND: Iatrogenic transmission of human prion disease can occur through medical or surgical procedures, including injection of hormones such as gonadotropins extracted from cadaver pituitaries. Annually, more than 300,000 women in the United States and Canada are prescribed urine-derived gonadotropins for infertility. Although menopausal urine donors are screened for symptomatic neurological disease, incubation of Creutzfeldt-Jakob disease (CJD) is impossible to exclude by non-invasive testing. Risk of carrier status of variant CJD (vCJD), a disease associated with decades-long peripheral incubation, is estimated to be on the order of 100 per million population in the United Kingdom. Studies showing infectious prions in the urine of experimental animals with and without renal disease suggest that prions could be present in asymptomatic urine donors. Several human fertility products are derived from donated urine; recently prion protein has been detected in preparations of human menopausal gonadotropin (hMG). METHODOLOGY/PRINCIPAL FINDINGS: Using a classical proteomic approach, 33 and 34 non-gonadotropin proteins were identified in urinary human chorionic gonadotropin (u-hCG) and highly-purified urinary human menopausal gonadotropin (hMG-HP) products, respectively. Prion protein was identified as a major contaminant in u-hCG preparations for the first time. An advanced prion protein targeted proteomic approach was subsequently used to conduct a survey of gonadotropin products; this approach detected human prion protein peptides in urine-derived injectable fertility products containing hCG, hMG and hMG-HP, but not in recombinant products. CONCLUSIONS/SIGNIFICANCE: The presence of protease-sensitive prion protein in urinary-derived injectable fertility products containing hCG, hMG, and hMG-HP suggests that prions may co-purify in these products. Intramuscular injection is a relatively efficient route of transmission of human prion disease, and young women exposed to prions can be expected to survive an incubation period associated with a minimal inoculum. The risks of urine-derived fertility products could now outweigh their benefits, particularly considering the availability of recombinant products

Two Chromogranin A-Derived Peptides Induce Calcium Entry in Human Neutrophils by Calmodulin-Regulated Calcium Independent Phospholipase A2

Background: Antimicrobial peptides derived from the natural processing of chromogranin A (CgA) are co-secreted with catecholamines upon stimulation of chromaffin cells. Since PMNs play a central role in innate immunity, we examine responses by PMNs following stimulation by two antimicrobial CgA-derived peptides. Methodology/Principal Findings: PMNs were treated with different concentrations of CgA-derived peptides in presence of several drugs. Calcium mobilization was observed by using flow cytometry and calcium imaging experiments. Immunocytochemistry and confocal microscopy have shown the intracellular localization of the peptides. The calmodulin-binding and iPLA2 activating properties of the peptides were shown by Surface Plasmon Resonance and iPLA2 activity assays. Finally, a proteomic analysis of the material released after PMNs treatment with CgA-derived peptides was performed by using HPLC and Nano-LC MS-MS. By using flow cytometry we first observed that after 15 s, in presence of extracellular calcium, Chromofungin (CHR) or Catestatin (CAT) induce a concentration-dependent transient increase of intracellular calcium. In contrast, in absence of extra cellular calcium the peptides are unable to induce calcium depletion from the stores after 10 minutes exposure. Treatment with 2-APB (2-aminoethoxydiphenyl borate), a store operated channels (SOCs) blocker, inhibits completely the calcium entry, as shown by calcium imaging. We also showed that they activate iPLA2 as the two CaM-binding factors (W7 and CMZ) and that the two sequences can be aligned with the two CaMbinding domains reported for iPLA2. We finally analyzed by HPLC and Nano-LC MS-MS the material released by PMNs following stimulation by CHR and CAT. We characterized several factors important for inflammation and innate immunity. Conclusions/Significance: For the first time, we demonstrate that CHR and CAT, penetrate into PMNs, inducing extracellular calcium entry by a CaM-regulated iPLA2 pathway. Our study highlights the role of two CgA-derived peptides in the active communication between neuroendocrine and immune systems

Nuclear transition protein 1 from ram elongating spermatids. Mass spectrometric characterization primary culture and phosphorylation sites of two variants

International audienceThe ram transition protein 1 (TP1) is present in spermatid cell nuclei in the nonphosphorylated, monophosphorylated and diphosphorylated forms. Its primary structure was determined by automated Edman degradation of S-carboxamidomethylated protein and of peptides generated by cleavage with thermolysin and endoproteinase Lys-c. The ram TP1 is a small basic protein of 54 residues and structurally very close to other mammalian TPI. The mass spectrometric data obtained from the protein and its fragments reveal that ram TP1 is indeed a mixture (approximately 5: 1) of two structural variants (M, 6346 and 6300). These variants differ only by the nature of the residue at position 27 (Cys in the major variant and Gly in the minor variant). The study of phosphorylation sites has shown that four different serine residues could be phosphorylated in the monophosphorylated TPI, at positions 8, 35, 36 or 39. From previous physical studies, it has been postulated that the Tyr32 surrounded by two highly conserved basic clusters was responsible for the destabilization of chromatin by intercalation of its phenol ring between the bases of double-stranded DNA. The presence of three phosphorylatable serine residues in the very conserved sequence 29 -42 is another argument for the involvement of this region in the interaction with DNA

Differential display of peptides induced during the immune response of Drosophila: A matrix-assisted laser desorption ionization time-of-flight mass spectrometry study

We have developed an approach based on a differential mass spectrometric analysis to detect molecules induced during the immune response of Drosophila, regardless of their biological activities. For this, we have applied directly matrix-assisted laser desorption/ionization MS to hemolymph samples from individual flies before and after an immune challenge. This method provided precise information on the molecular masses of immune-induced molecules and allowed the detection, in the molecular range of 1.5–11 kDa, of 24 Drosophila immune-induced molecules (DIMs). These molecules are all peptides, and four correspond to already characterized antimicrobial peptides. We have further analyzed the induction of the various peptides by immune challenge in wild-type flies and in mutants with a compromised antimicrobial response. We also describe a methodology combining matrix-assisted laser desorption ionization time-of-flight MS, HPLC, and Edman degradation, which yielded the peptide sequence of three of the DIMs. Finally, molecular cloning and Northern blot analyses revealed that one of the DIMs is produced as a prepropeptide and is inducible on a bacterial challenge