Phospholipase A1 Member A Activates Fibroblast-like Synoviocytes through the Autotaxin-Lysophosphatidic Acid Receptor Axis.

Lysophosphatidylserine (lysoPS) is known to regulate immune cell functions. Phospholipase A1 member A (PLA1A) can generate this bioactive lipid through hydrolysis of sn-1 fatty acids on phosphatidylserine (PS). PLA1A has been associated with cancer metastasis, asthma, as well as acute coronary syndrome. However, the functions of PLA1A in the development of systemic autoimmune rheumatic diseases remain elusive. To investigate the possible implication of PLA1A during rheumatic diseases, we monitored PLA1A in synovial fluids from patients with rheumatoid arthritis and plasma of early-diagnosed arthritis (EA) patients and clinically stable systemic lupus erythematosus (SLE) patients. We used human primary fibroblast-like synoviocytes (FLSs) to evaluate the PLA1A-induced biological responses. Our results highlighted that the plasma concentrations of PLA1A in EA and SLE patients were elevated compared to healthy donors. High concentrations of PLA1A were also detected in synovial fluids from rheumatoid arthritis patients compared to those from osteoarthritis (OA) and gout patients. The origin of PLA1A in FLSs and the arthritic joints remained unknown, as healthy human primary FLSs does not express the PLA1A transcript. Besides, the addition of recombinant PLA1A stimulated cultured human primary FLSs to secrete IL-8. Preincubation with heparin, autotaxin (ATX) inhibitor HA130 or lysophosphatidic acid (LPA) receptor antagonist Ki16425 reduced PLA1A-induced-secretion of IL-8. Our data suggested that FLS-associated PLA1A cleaves membrane-exposed PS into lysoPS, which is subsequently converted to LPA by ATX. Since primary FLSs do not express any lysoPS receptors, the data suggested PLA1A-mediated pro-inflammatory responses through the ATX-LPA receptor signaling axis.

Metabolite Profiling of Two Maple-Derived Products Using Dereplication Based on High-Performance Liquid Chromatography-Diode Array Detector-Electrospray Ionization-Time-of-Flight-Mass Spectrometry: Sugar Maple Bark and Bud Hot-Water Extracts.

Recent studies about hot-water extracts from sugar maple (Acer saccharum Marsh.) bark and buds demonstrated that they contain high amounts of phenolic structures that may be used as antioxidant food additives. However, the detailed chemical composition of these maple-derived extracts has yet to be determined. By performing high-performance liquid chromatography-diode array detector-high-resolution mass spectrometry (HPLC-DAD-HRMS)-based dereplication, we were able to spike and classify almost 100 metabolites in each hot-water extract. The sugar maple bark hot-water extract is rich in simple phenolic compounds and phenylpropanoid derivatives, while bud extract contains predominantly flavonoids, benzoic acids, and their complex derivatives (condensed and hydrolyzable tannins). Among those chemical structures, we tentatively identified 69 phenolic compounds potentially reported for the first time in the genus Acer. Considering the growing commercial demand in natural products, the phenolic fingerprints of sugar maple bark and bud hot-water extracts will help in promoting these two maple-derived products as new sources of bioactive compounds in the food, nutraceutical, and cosmetic industries.

Anhydroglucitol-core gallotannins from red maple buds modulate viability of human blood neutrophils.

Apoptosis of neutrophils is an essential checkpoint for the resolution of inflammation by shutting down the deleterious functions of these immune cells. This study investigated the role of anhydroglucitol-core gallotannins (ACGs) in apoptosis increase of human blood neutrophils treated by the hot water extract from red maple buds (RMB). Fractions obtained by liquid-liquid partitioning (ethyl acetate, butanol and water-remaining fractions) of the hot water extract from RMB were assessed for their effects on neutrophil viability by using flow cytometry. These fractions were then phytochemically analyzed to investigate the ability of major compounds to induce neutrophil apoptosis individually. Ethyl acetate and butanol fractions that contained the major ACGs ginnalin A, ginnalin 3,6 and ginnalin C stimulated the apoptosis of neutrophils. The three ACGs at 100 µM significantly increased the rate of the late apoptotic cells. When differentially combined, these ACGs have additive or antagonist effects. These effects are related to the concentrations of the constituents in the mixtures studied, especially so for ginnalin C. GinA increased FADD, phospho-Rad17, SMAC/Diablo and cytochrome C, while decreasing the anti-apoptotic protein catalase. These compounds could be useful for the development of novel therapeutic approaches that facilitate resolution of neutrophil-mediated inflammatory diseases.

Nutrients, Antioxidant Capacity and Safety of Hot Water Extract from Sugar Maple (Acer saccharum M.) and Red Maple (Acer rubrum L.) Bark.

Sugar maple (Acer saccharum M.) and red maple (Acer rubrum L.) barks were treated with hot water to extract nutrients in order to explore, for the first time, its potential as safe dietary antioxidants. The organic and inorganic nutrients of these extracts, as well as their safety on human PLB-985 cells differentiated into neutrophils-like cells, were determined. Proximate analysis showed that both bark extracts were low in moisture and fat. Sugar maple bark extract (SM-BX) showed crude protein and ash content higher than those found in red maple bark extract (RM-BX). In addition, SM-BX had total sugars higher than those evaluated in RM-BX, while complex sugars (oligo- and/or poly-saccharides) were similarly abundant in both bark extracts. Furthermore, SM-BX demonstrated a wide array of vital minerals (K, Ca, Mg, P, Na, Fe and Cu) in quantity larger than that evaluated in RM-BX, whereas RM-BX have Zn and Mn levels higher than those found in SM-BX. Phytochemical analyses showed that RM-BX exhibited total phenolic and flavonoid contents higher than those measured in SM-BX. Consequently, RM-BX presented an antioxidant activity higher than that of SM-BX: 2.85-fold ABTS radical cation scavenging capacity and 1.9-fold oxygen radical absorbance capacity. Finally, RM-BX and SM-BX were greatly safe since, at concentration up to 100 µg/ml, they did not modify the viability of neutrophils as determined by flow-cytometry assay using Annexin V-FITC/Propidum Iodide as markers. In conclusion, our in vitro studies indicate that both red and sugar maple bark extracts have a real potential as food additives.

Antioxidant Capacity, Phenolic Constituents and Toxicity of Hot Water Extract from Red Maple Buds.

The present study reports, for the first time, the results of the antioxidant capacity and the phenolic composition of a hot water extract from red maple buds (RMB), as well as its safety. In this regard and comparatively to antioxidant standards, this extract exhibits a significant antiradical capacity when tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH· ) and anion superoxide trapping assays. High-resolution mass spectrometric and nuclear magnetic resonance analyses permitted to determine for the first time, in red maple species, cyanidin-3-O-glucoside, quercetin-3-O-galactoside, quercetin-3-O-arabinoside, and quercetin. Also, the quantification of individual phenolics by high-performance liquid chromatography method revealed that ginnalin A at 117.0 mg/g is the major compound of RMB hot water extract. Finally, using flow cytometry evaluation, the extract of RMB was determined to have no toxicity neither to cause significant modification of apoptosis process, up to concentration of 100 µg/ml, on human peripheral blood neutrophils. These results allow anticipating various fields of application of RMB water extract.

Platelet microparticles are internalized in neutrophils via the concerted activity of 12-lipoxygenase and secreted phospholipase A2-IIA.

Platelets are anucleated blood elements highly potent at generating extracellular vesicles (EVs) called microparticles (MPs). Whereas EVs are accepted as an important means of intercellular communication, the mechanisms underlying platelet MP internalization in recipient cells are poorly understood. Our lipidomic analyses identified 12(S)-hydroxyeicosatetranoic acid [12(S)-HETE] as the predominant eicosanoid generated by MPs. Mechanistically, 12(S)-HETE is produced through the concerted activity of secreted phospholipase A2 IIA (sPLA2-IIA), present in inflammatory fluids, and platelet-type 12-lipoxygenase (12-LO), expressed by platelet MPs. Platelet MPs convey an elaborate set of transcription factors and nucleic acids, and contain mitochondria. We observed that MPs and their cargo are internalized by activated neutrophils in the endomembrane system via 12(S)-HETE. Platelet MPs are found inside neutrophils isolated from the joints of arthritic patients, and are found in neutrophils only in the presence of sPLA2-IIA and 12-LO in an in vivo model of autoimmune inflammatory arthritis. Using a combination of genetically modified mice, we show that the coordinated action of sPLA2-IIA and 12-LO promotes inflammatory arthritis. These findings identify 12(S)-HETE as a trigger of platelet MP internalization by neutrophils, a mechanism highly relevant to inflammatory processes. Because sPLA2-IIA is induced during inflammation, and 12-LO expression is restricted mainly to platelets, these observations demonstrate that platelet MPs promote their internalization in recipient cells through highly regulated mechanisms.

Picea mariana polyphenolic extract inhibits phlogogenic mediators produced by TNF-α-activated psoriatic keratinocytes: Impact on NF-κB pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Picea mariana ((Miller) Britton, Sterns, and Poggenburg; Pinaceae) bark has been traditionally used by North American natives for treating topical inflammations. It has been also suggested to improve various inflammatory skin disorders like Psoriasis vulgaris. Extracts from this bark storage protein contain polyphenolic compounds which have well-known antiinflammatory activities. Based on the capacity of polyphenolic compounds to modulate functions of normal human keratinocytes, this study was set up to decipher the mechanisms of action of a chemically characterized polyphenolic extract from Picea mariana bark (BS-EAcf) on lesional keratinocytes of skin with psoriasis vulgaris, a disease driven by the immune system in which TNF-α plays a significant role. MATERIALS AND METHODS: BS-EAcf corresponds to the ethyl acetate soluble fraction from the hot water extract of Picea mariana bark. BS-EAcf effects were evaluated in normal human (NHK) and psoriatic (PK) keratinocytes stimulated by TNF-α. Cell viability was assessed by lactate deshydrogenase release and propidium iodide (PI) staining. The mechanisms of action of BS-EAcf in keratinocytes were investigated by flow cytometry, ELISAs, RT-PCR and western blot analyses. RESULTS: PK exhibited a higher response to TNF-α than NHK regarding the ICAM-1 expression and the production of NO, IL-6, IL-8, fractalkine and PGE2, whereas BS-EAcf significantly inhibited this TNF-α-induced increase at concentrations without causing keratinocyte toxicity. Additionally, this extract significantly inhibited the TNF-α-induced release of elafin and VEGF by PK and NHK. Since TNF-α activation of most of these factors is dependent on the NF-κB pathway, this latter was studied in TNF-α-activated PK. BS-EAcf inhibited the TNF-α-induced phosphorylation and degradation of total IκBα as well as phosphorylation of NF-κB p65. CONCLUSIONS: The ethyl acetate fraction from Picea mariana bark extract showed inhibitory effects of cytokines, chemokines, adhesion molecules, nitric oxide and prostaglandins produced by keratinocytes under TNF-α activation through down-regulating the NF-κB pathway. This study demontrated that this extract could be a potential antiinflammatory agent capable of improving psoriatic skin.

α2ß1 integrin regulates Th17 cell activity and its neutralization decreases the severity of collagen-induced arthritis.

Th17 cells play a critical role in the pathogenesis of rheumatoid arthritis (RA), but the mechanisms by which these cells regulate the development of RA are not fully understood. We have recently shown that α2ß1 integrin, the receptor of type I collagen, is the major collagen-binding integrin expressed by human Th17 cells. In this study, we examined the role of α2ß1 integrin in Th17-mediated destructive arthritis in the murine model of collagen-induced arthritis (CIA). We found that α2ß1 integrin is expressed on synovial Th17 cells from CIA mice and its neutralization with a specific mAb significantly reduced inflammation and cartilage degradation, and protected the mice from bone erosion. Blockade of α2ß1 integrin led to a decrease in the number of Th17 cells in the joints and to a reduction of IL-17 levels in CIA mice. This was associated with an inhibition of receptor activator of NF-κB ligand levels and osteoclast numbers, and reduction of bone loss. We further show that α2ß1 integrin is expressed on synovial Th17 cells from RA patients, and that its ligation with collagen costimulated the production of IL-17 by polarized human Th17 cells by enhancing the expression of retinoic acid receptor-related orphan receptor C through ERK and PI3K/AKT. Our findings provide the first evidence, to our knowledge, that α2ß1 integrin is an important pathway in Th17 cell activation in the pathogenesis of CIA, suggesting that its blockade can be beneficial for the treatment of RA and other Th17-associated autoimmune diseases.

XP-828L in the treatment of mild to moderate psoriasis: randomized, double-blind, placebo-controlled study.

BACKGROUND: XP-828L, a protein extract obtained from sweet whey, has demonstrated potential benefit for the treatment of mild to moderate psoriasis in an open-label study. OBJECTIVE: To study in a randomized, double-blind, placebo-controlled study the safety and efficacy of XP-828L in the treatment of mild to moderate psoriasis. DESIGN: XP-828L 5 g/d (group A, n=42) or placebo (group B, n=42) was given orally for 56 days followed by XP-828L 5 g/d in group A and by XP-828L 10 g/d in group B for an additional 56 days. RESULTS: Patients receiving XP-828L 5 g/d for 56 days had an improved Physician's Global Assessment (PGA) score compared with patients under placebo (p less than 0.05). Considering the data of group A only, the PGA score improved from day 1 to day 56 (p less than 0.01); the Psoriasis Area and Severity Index score improved as well, but to a lesser extent (p less than 0.05). CONCLUSION: Oral administration of 5 g/d XP-828L compared with a placebo significantly improved the PGA score of patients with mild to moderate psoriasis.

XP-828L (Dermylex), a new whey protein extract with potential benefit for mild to moderate psoriasis.

Natural health products (NHPs) or complementary and alternative medicine (CAM) are commonly used to prevent disorders or support the usual treatments of many diseases. XP-828L, a whey protein extract, has demonstrated potential benefits for the treatment of mild to moderate psoriasis. The aim of this study was to analyze further clinical data that demonstrated the clinical benefits and safety of the XP-828L in patients with psoriasis and the potential mechanism of action of this product in vitro. Oral administration (2.5 g, twice a day, over 112 days) of XP-828L in 42 human subjects with mild to moderate psoriasis improved their PGA scores (physician's global assessment). Moreover, no significant changes in haematology or hepatic and renal parameters were observed throughout the study period, indicating the safety of the product. In vitro experiments showed that XP-828L decreased the proliferation of concanavalin A (ConA)-stimulated murine splenocytes and their production of interleukin (IL)-2 and interferon (IFN)-gamma. Although the in vivo mechanism of action of XP-828L remains unknown, XP-828L represents an NHP to be used as an alternative or concomitant treatment for mild to moderate psoriasis and potentially for other immune-mediated diseases.

Human neutrophils as a source of nociceptin: a novel link between pain and inflammation.

Nociceptin is a neuropeptide sharing sequence homology with classical opioid peptides but with a distinct pharmacological profile. Through activation of its receptor, NociR, nociceptin has been linked with several physiological functions in the central nervous system including memory, locomotion, and processing of pain signals. Recently, peripheral blood neutrophils (PMNs) were demonstrated to express a functional NociR, a result suggesting that additional functions of the neuropeptide remain to be elucidated. The present study investigated the possibility that PMNs may be a source of nociceptin and whether the neuropeptide elicits PMN early responses. We observed the presence of nociceptin in the synovial fluids from arthritic patients, an inflammatory milieu typically containing high numbers of PMNs. In addition, freshly isolated PMNs were found to express and secrete nociceptin following degranulation, identifying these inflammatory cells as a novel source of the neuropeptide. Incubation of PMNs with nociceptin elicited a specific pattern of cellular protein phosphorylation on tyrosine residues in a rapid and transient fashion. Moreover, nociceptin prevented intracellular accumulation of cAMP in fMLP-stimulated PMNs, an effect mimicked by the specific NociR synthetic agonist, Ro 64-6198. Taken together, these results show that nociceptin/NociR is present and functional in human neutrophils, and the results identify a novel dialogue pathway between neural and immune tissues.

Inflammatory microcrystals alter the functional phenotype of human osteoblast-like cells in vitro: synergism with IL-1 to overexpress cyclooxygenase-2.

Chronic crystal-associated arthropathies such as gout and pseudogout can lead to local bone destruction. Because osteoblasts, which orchestrate bone remodeling via soluble factors and cell-to-cell interactions, have been described in contact with microcrystals, particularly in uratic foci of gout, we hypothesized that microcrystals of monosodium urate monohydrate (MSUM) and of calcium pyrophosphate dihydrate (CPPD) could alter osteoblastic functions. MSUM and CPPD adhered to human osteoblastic cells (hOB) in vitro and were partly phagocytized as shown by scanning electron microscopy. MSUM and CPPD dose-dependently stimulated the production of PGE(2) in hOB as assessed by enzyme immunoassay, a response that was synergistically enhanced in the presence of IL-1. The mechanism of this synergism was, at least in part, at the level of the expression of cyclooxygenase-2 as evaluated by immunoblot analysis. MSUM and CPPD also stimulated the expression of IL-6 and IL-8 and reduced the 1,25-dihydroxyvitamin D(3)-induced activity of alkaline phosphatase and osteocalcin in hOB (with no synergism with IL-1). MSUM- or CPPD-stimulated expression of IL-6 in hOB pretreated with the selective cyclooxygenase-2 inhibitor NS-398 was increased, unlike that induced by IL-1 alone which was partially reduced. MSUM-, CPPD- or IL-1-induced expression of IL-8 was unchanged by pretreating hOB with NS-398. These results suggest that inflammatory microcrystals alter the normal phenotype of hOB, redirecting them toward reduced bone formation and amplified osteoblast-mediated bone resorption, abnormalities that could play a role in the bone destruction associated with chronic crystal-induced arthritis.