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1.
Bioresour Bioprocess ; 11(1): 68, 2024 Jul 16.
Article de Anglais | MEDLINE | ID: mdl-39012554

RÉSUMÉ

To understand the ecology of species and promote biotechnology through beneficial strain selection for improving starch yield in maize wet-milling steeping, bacterial diversity and community structure during the counter-current steeping process in a commercial steeping system were characterized and investigated. The microbial diversity in the steeping liquor, which consisted of 16 phyla, 131 families, and 290 genera, was more abundant compared to those present on the surface of unsteeped maize. As the counter-current steeping progressed, exposing newer maize to the older steepwater, Lactobacillus dominated, replacing Rahnella, Pseudomonas, Pantoea, and Serratia. The thermophilic and acidophilic microbial consortia were enriched through adaptive evolution engineering and employed to improve starch yield. Several steeping strategies were evaluated, including water alone, SO2 alone, mono-culture of B. coagulans, microbial consortia, and a combination of consortium and SO2. Combining the microbial consortium with SO2 significantly increased the starch yield to, about 66.4 ± 0.5%, a 22% and 46% increase over SO2 alone and the consortium alone, respectively. Scanning electron microscope (SEM) of steeped maize structure indicated that the combination of consortium and SO2 disrupted the protein matrix and widened gaps between starch granules in maize endosperm. This released proteins into the steepwater and left starch granules in the aleurone layer. The steeping strategy of using thermophilic and acidophilic microbial consortium as additives shows potential application as an environmentally friendly alternative to conventional maize steeping procedures.

2.
J Proteome Res ; 20(6): 3078-3089, 2021 06 04.
Article de Anglais | MEDLINE | ID: mdl-33793249

RÉSUMÉ

The leukocyte immunoglobulin-like receptor A3 (LILRA3) is a soluble protein primarily expressed by peripheral blood monocytes and is abundant in sera of healthy donors. Extracellular LILRA3 is anti-inflammatory and displays neuro-regenerative functions in vitro. However, its intracellular expression, distribution, and function(s) remain unknown. Using a combination of high-resolution confocal and super-resolution microscopy, we identified intracellular expression of native LILRA3 in the nucleus of peripheral blood monocytes and in vitro-derived macrophages. This unexpected nuclear localization of LILRA3 was confirmed in LILRA3-GFP-transfected HEK293T cells. Western blot of proteins fractionated from primary macrophages and the transfected HEK293T cells confirmed nuclear localization of the native and expressed LILRA3 proteins. Interestingly, most of the LILRA3 in the nucleus was in a monomeric form like the biologically active secreted protein, while that in the other cellular compartments was in mixed monomeric, dimeric, and oligomeric forms. The predominant presence of monomeric LILRA3 in the nucleus was independently corroborated in transfected live HEK293T cells using the number and molecular brightness (N&B) analysis method. Immunoprecipitation and mass spectrometric peptide sequencing studies revealed that nuclear LILRA3 co-immunoprecipitated with several nuclear proteins involved in host protein synthesis machinery via direct interactions to a key multifunctional RNA-binding protein, the Ewing sarcoma breakpoint region 1 protein (EWS) (data are available via ProteomeXchange with identifier PXD024602). The biological significance of the nuclear expression of LILRA3 and its interaction with these key proteins remain to be elucidated.


Sujet(s)
Monocytes , Récepteurs immunologiques , Expression des gènes , Cellules HEK293 , Humains , Immunoglobulines , Récepteurs immunologiques/génétique
3.
Eur J Immunol ; 51(7): 1732-1747, 2021 07.
Article de Anglais | MEDLINE | ID: mdl-33844287

RÉSUMÉ

Long-lived T-memory stem cells (TSCM ) are key to both naturally occurring and vaccine-conferred protection against infection. These cells are characterized by the CD45RA+ CCR7+ CD95+ phenotype. Significant heterogeneity within the TSCM population is recognized, but distinguishing surface markers and functional characterization of potential subsets are lacking. Human CD8 TSCM subsets were identified in healthy subjects who had been previously exposed to CMV or Influenza (Flu) virus in flow cytometry by expression of CD122 or CXCR3, and then characterized in proliferation, multipotency, self-renewal, and intracellular cytokine production (TNF-α, IL-2, IFN-γ), together with transcriptomic profiles. The TSCM CD122hi -expressing subset (versus CD122lo ) demonstrated greater proliferation, greater multipotency, and enhanced polyfunctionality with higher frequencies of triple positive (TNF-α, IL-2, IFN-γ) cytokine-producing cells upon exposure to recall antigen. The TSCM CXCR3lo subpopulation also had increased proliferation and polyfunctional cytokine production. Transcriptomic analysis further showed that the TSCM CD122hi population had increased expression of activation and homing molecules, such as Ccr6, Cxcr6, Il12rb, and Il18rap, and downregulated cell proliferation inhibitors, S100A8 and S100A9. These data reveal that the TSCM CD122hi phenotype is associated with increased proliferation, enhanced multipotency and polyfunctionality with an activated memory-cell like transcriptional profile, and hence, may be favored for induction by immunization and for adoptive immunotherapy.


Sujet(s)
Lymphocytes T CD8+/immunologie , Mémoire immunologique/immunologie , Sous-unité bêta du récepteur à l'interleukine-2/immunologie , Récepteurs CXCR3/immunologie , Antigènes/immunologie , Cytokines/immunologie , Humains , Immunothérapie adoptive/méthodes , Phénotype , Cellules souches/immunologie
4.
Biosci Microbiota Food Health ; 39(4): 199-208, 2020.
Article de Anglais | MEDLINE | ID: mdl-33117618

RÉSUMÉ

Plant proteins are known to possess important bioactive peptides and have a positive impact on gut microbial modulation. In this study, we studied the ability of a single dose of a fermented soy protein product (P-SPI) to reduce high blood pressure in spontaneous hypertensive rats (SHR) and how it modulates the gut microbiota after six weeks of feeding. SHRs were fed with P-SPI, Captopril or distilled water once, and their blood pressures were monitored from the first to twelfth-hour post-administration. Consumption of P-SPI significantly reduced systolic and diastolic blood pressures up to the sixth hour by 25 ± 4 mmHg and 40 ± 5 mmHg respectively. P-SPI consumption inhibited serum ACE activity, increased superoxide dismutase activity and nitric oxide levels and reduced malondialdehyde levels in serum. Analysis of fecal microbial 16S rRNA of hypertensive rats revealed a significant reduction in microbial richness and diversity in the gut, while P-SPI consumption improved microbial richness and increased diversity. Also, P-SPI feeding significantly reduced the Firmicutes/Bacteroidetes ratio, increased propionate- and H2S-producing bacteria and reduced Streptococcaceae and Erysipelotrichales levels. Our results show that P-SPI is a potential antihypertensive functional food which could remodel the altered gut microbiota of hypertensive patients.

5.
Food Chem Toxicol ; 129: 337-343, 2019 Jul.
Article de Anglais | MEDLINE | ID: mdl-31071387

RÉSUMÉ

This study assesses the ability of anthraquinone derivative, 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone (MTAQ) to decrease postprandial hyperglycemia or enhance glucose uptake and to elucidate the underlying molecular mechanism. We investigated α-glucosidase inhibition, glucose uptake, and translocation of glucose transporter 4 (GLUT4) in C2C12 myotubes. The data indicate that MTAQ strongly inhibited α-glucosidase activity in a concentration-dependent manner, with an IC50 value of 6.49 ±â€¯1.31 µM, and functioned as a reversible competitive inhibitor, with a dissociation constant of 41.88 µM. Moreover, MTAQ significantly augmented basal and insulin-stimulated glucose uptake as well as translocation of GLUT4 to the plasma membrane. It also stimulated the phosphorylation of insulin receptor ß isoform, insulin receptor substrate-1,3-phosphoinositide-dependent protein kinase 1, and protein kinase B (AKT). A pretreatment with an AKT inhibitor, LY294002, attenuated the ability of MTAQ to activate an insulin-like signaling pathway and to enhance basal and insulin-stimulated glucose uptake and stimulate GLUT4 translocation to the plasma membrane. These findings reveal the fact that MTAQ may have potential for the development of new antidiabetic drugs to manage blood glucose levels.


Sujet(s)
Anthraquinones/pharmacologie , Glucose/métabolisme , Inhibiteurs des glycoside hydrolases/pharmacologie , Insuline/métabolisme , Fibres musculaires squelettiques/effets des médicaments et des substances chimiques , Transduction du signal/effets des médicaments et des substances chimiques , Animaux , Lignée cellulaire , Transporteur de glucose de type 4/métabolisme , Hypoglycémiants/pharmacologie , Cinétique , Souris , Fibres musculaires squelettiques/métabolisme , Transport des protéines
6.
Sci Rep ; 9(1): 1149, 2019 02 04.
Article de Anglais | MEDLINE | ID: mdl-30718719

RÉSUMÉ

The non-integrin 37/67-kDa laminin receptor (LAMR1) is a complex protein with diverse functions. LAMR1 is widely expressed in epithelial cells and recently it was reported on neutrophils and a subset of activated T cells. Ligation of LAMR1 on peripheral blood mononuclear cells (PBMC) downregulated LPS-induced TNFα production, suggesting immune functions. However, its expression on primary monocytes remain unknown. Interestingly, LAMR1 mRNA is downregulated in PBMC of patients with early rheumatoid arthritis (RA), and low gene expression is an independent predictor of poor response to anti-TNFα treatment, suggesting a role in RA pathogenesis. We found LAMR1 was constitutively expressed on all peripheral blood monocytes and a subset of B cells from healthy individuals and patients with RA and it was abundantly present in synovial tissue of patients with RA. On monocytes and synovial tissue lower levels of LAMR1 expression tended to correlate with increased disease activity scores. In vitro treatment of monocytes with IFNγ or IL-10 up-regulated surface LAMR1 in healthy individuals and patients with RA with greater effects observed in healthy individuals. Importantly, treatment with IFNγ significantly increased specific binding of monocytes to laminin-1. TNFα and IL-1ß caused marginal downregulation of LAMR1 in patients but effects in controls were variable. Taken together, constitutively expressed LAMR1 on monocytes is differentially regulated by pro-inflammatory and immune-regulatory cytokines suggesting LAMR1 may regulate the threshold and amplitude of their activation and migration. Decreased levels in patients with RA may indicate loss of this potentially critical homeostatic regulation thereby contributing to the excessive inflammation.


Sujet(s)
Polyarthrite rhumatoïde/immunologie , Sous-populations de lymphocytes B/immunologie , Agranulocytes/immunologie , Récepteur laminine/sang , Protéines ribosomiques/sang , Synovie/immunologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Sous-populations de lymphocytes B/anatomopathologie , Cytokines/immunologie , Femelle , Humains , Agranulocytes/anatomopathologie , Mâle , Adulte d'âge moyen
7.
Oxid Med Cell Longev ; 2018: 5796102, 2018.
Article de Anglais | MEDLINE | ID: mdl-30510623

RÉSUMÉ

Glucose absorption from the gut and glucose uptake into muscles are vital for the regulation of glucose homeostasis. In the current study, we determined if gossypol (GSP) reduces postprandial hyperglycemia or enhances glucose uptake; we also investigated the molecular mechanisms underlying those processes in vitro and in vivo. GSP strongly and concentration dependently inhibited α-glucosidase by functioning as a competitive inhibitor with IC50 value of 0.67 ± 0.44. GSP activated the insulin receptor substrate 1 (IRS-1)/protein kinase B (Akt) signaling pathways and enhanced glucose uptake through the translocation of glucose transporter 4 (GLUT4) into plasma membrane in C2C12 myotubes. Pretreatment with a specific inhibitor attenuated the in vitro effects of GSP. We used a streptozotocin-induced diabetic mouse model to assess the antidiabetic potential of GSP. Consistent with the in vitro study, a higher dose of GSP (2.5 mg/kg-1) dramatically decreased the postprandial blood glucose levels associated with the upregulated expressions of GLUT4 and the IRS-1/Akt-mediated signaling cascade in skeletal muscle. GSP treatment also significantly boosted antioxidant enzyme expression and mitigated gluconeogenesis in the liver. Collectively, these data imply that GSP has the potential in managing and preventing diabetes by ameliorating glucose uptake and improving glucose homeostasis.


Sujet(s)
Huile de coton/composition chimique , Diabète expérimental/traitement médicamenteux , Glucose/métabolisme , Gossypol/pharmacologie , Insuline/pharmacologie , Transduction du signal , Animaux , Transport biologique , Contraceptifs masculins/pharmacologie , Diabète expérimental/métabolisme , Diabète expérimental/anatomopathologie , Homéostasie , Hypoglycémiants/pharmacologie , Mâle , Souris , Souris de lignée BALB C , Fibres musculaires squelettiques/effets des médicaments et des substances chimiques , Fibres musculaires squelettiques/métabolisme , Fibres musculaires squelettiques/anatomopathologie
8.
Biol Pharm Bull ; 41(10): 1606-1610, 2018.
Article de Anglais | MEDLINE | ID: mdl-30270331

RÉSUMÉ

ß-Escin, a natural triterpene saponin was extracted from Aesculus hippocastanum seeds, which have been widely used to treat inflammation in traditional medicine. In an effort to study the possible anti-tumor effects of ß-escin, we performed wound healing, invasion, and adhesion assays to examine the effects of ß-escin on cell migration, invasion, and angiogenesis. Our results revealed that ß-escin inhibits cell migration as well as motility in B16F10 and SK-MEL5 cells in a dose-dependent manner. RT-PCR and Western blot analysis showed that ß-escin increased TIMP-1, -2 while significantly downregulated phosphorylated extracellular signal-regulated kinase (p-ERK) expression, and suppressing nuclear factor-kappa B (NF-κB) and inhibitor of nuclear factor-kappa B (IκB) expression. Overall, the data from the current study suggest that ß-escin has the potential for inhibiting both metastatic and angiogenic activities, and are the earliest evidence for the involvement of the NF-κB/IκB signaling in ß-escin-induced anti-tumor effects.


Sujet(s)
Aesculus/composition chimique , Aescine/pharmacologie , Extracellular Signal-Regulated MAP Kinases/métabolisme , Système de signalisation des MAP kinases , Mélanome/métabolisme , Facteur de transcription NF-kappa B/métabolisme , Extraits de plantes/pharmacologie , Animaux , Antinéoplasiques d'origine végétale/pharmacologie , Antinéoplasiques d'origine végétale/usage thérapeutique , Apoptose , Lignée cellulaire tumorale , Mouvement cellulaire , Prolifération cellulaire , Régulation négative , Aescine/usage thérapeutique , Humains , Protéines I-kappa B/métabolisme , Mélanome/traitement médicamenteux , Souris , Phosphorylation , Phytothérapie , Extraits de plantes/usage thérapeutique , Graines , Transduction du signal
9.
BMC Complement Altern Med ; 18(1): 200, 2018 Jul 03.
Article de Anglais | MEDLINE | ID: mdl-29970094

RÉSUMÉ

BACKGROUND: Cancer is one of the most frequently occurring diseases and is the second leading cause of death worldwide. In this study, anthraquinone derivatives (Compounds 1-5) were evaluated for their anti-cancer potential against various skin and breast cancer cell lines to assess whether these anthraquinone derivatives may serve as a lead for the augmentation of anti-cancer drug. METHODS: Anthraquinone derivatives, 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(6'-O-acetyl)-α-rhamnosyl(1 → 2)-ß-glucoside (Comp 1), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone (Comp 2), and alizarin (Comp 3) were isolated from the dichloromethane fraction of the roots of Rubia philippinensis., whereas ethyl acetate fraction yielded xanthopurpurin (Comp 4) and lucidin-ω-methyl ether (Comp 5). Structures of all the isolated compounds were determined by spectral data analysis. All isolated compounds (Comp 1-5) were assessed for cytotoxicity by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against four different cancer cell lines, i.e. human melanoma (SK-MEL-5), murine melanoma (B16F10), and human breast adenocarcinoma (MCF7 and MDA-MB-231). RESULTS: Significant activity of the compounds 4 and 5 was observed against the breast cancer cell line MDA-MB-231 with IC50 values of 14.65 ± 1.45 and 13.03 ± 0.33 µM, respectively. Encouragingly, IC50 values of 67.89 ± 1.02 and 79.01 ± 0.03 µM against normal kidney epithelial cells (MDCK) were also obtained for compounds 4 and 5, respectively, which indicated very low toxicity and favorable selectivity indices for compounds 4 and 5 in the range of 1.85 to 3.95 and 2.11 to 6.06 against skin cancer cell lines (SK-MEL-5, and B16F10), and breast cancer cell lines (MCF7 and MDA-MB-231), respectively. CONCLUSION: Our results suggested that the compounds 4 (xanthopurpurin) and 5 (lucidin-ω-methyl ether) showed high selective toxicity towards breast cancer cells at lower concentrations without showing toxicity towards normal cells, thus could be of potential as new lead molecules in cancer treatment.


Sujet(s)
Anthraquinones/pharmacologie , Antinéoplasiques/pharmacologie , Extraits de plantes/pharmacologie , Rubia/composition chimique , Anthraquinones/composition chimique , Antinéoplasiques/composition chimique , Lignée cellulaire tumorale , Survie cellulaire/effets des médicaments et des substances chimiques , Humains , Cellules MCF-7 , Extraits de plantes/composition chimique , Racines de plante/composition chimique
10.
Int J Mol Sci ; 19(3)2018 Mar 07.
Article de Anglais | MEDLINE | ID: mdl-29518952

RÉSUMÉ

In this study, the antimelanogenic effect of an ethyl acetate fraction of Oroxylum indicum Vent. seeds (OISEA) and its underlying mechanisms in melan-a cells were investigated. Antimelanogenesis activity was confirmed by assessing inhibition of tyrosinase activity and melanin content in the cells. Both transcriptional and translational expression of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase related protein-1 and 2 (TYRP-1 and TYRP-2), were also examined. The results depicted that pretreatment of OISEA significantly inhibits not only tyrosinase activity, but melanin production and intracellular tyrosinase activity. By repressing the expression of tyrosinase, TYRP-1, TYRP-2, and MITF, OISEA interrupted melanin production. Additionally, OISEA interfered with the phosphorylation of p38, extracellular signal-regulated kinase 1/2 (ERK1/2), and c-Jun N-terminal kinase (JNK), with the reversal of OISEA-induced melanogenesis inhibition after treatment with the specific inhibitors SB239063, U0126, and SP600125. Overall, these results suggest that OISEA can stimulate p38, ERK1/2, JNK phosphorylation, and subsequent suppression of melanin, leading to the inhibition of melanogenic enzymes and melanin production, possibly owing to the presence of polyphenolic compounds.


Sujet(s)
Bignoniaceae/composition chimique , Régulation de l'expression des gènes/effets des médicaments et des substances chimiques , Système de signalisation des MAP kinases/effets des médicaments et des substances chimiques , Mélanocytes/effets des médicaments et des substances chimiques , Mélanocytes/métabolisme , Facteur de transcription associé à la microphtalmie/génétique , Extraits de plantes/pharmacologie , Graines/composition chimique , Fractionnement chimique , Chromatographie en phase liquide à haute performance , Modèles biologiques , Extraits de plantes/composition chimique , Extraits de plantes/isolement et purification , ARN messager/génétique , ARN messager/métabolisme
11.
Article de Anglais | MEDLINE | ID: mdl-28607575

RÉSUMÉ

Glucose deposition in peripheral tissue is an important parameter for the treatment of type 2 diabetes mellitus. The aim of this study was to investigate the effects of Spatholobus suberectus (Ss) on glucose disposal in skeletal muscle cells and additionally explore its in vivo antidiabetic potential. Treatment of ethanolic extract of S. suberectus (EeSs) significantly enhanced the glucose uptake, mediated through the enhanced expression of GLUT4 in skeletal muscle via the stimulation of AKT and AMPK pathways in C2C12 cells. Moreover, EeSs have potential inhibitory action on α-glucosidase activity and significantly lowered the postprandial blood glucose levels in STZ-induced diabetic mice, associated with increased expression of GLUT4 and AKT and/or AMPK-mediated signaling cascade in skeletal muscle. Furthermore, administration of EeSs significantly boosted up the antioxidant enzyme expression and also mitigated the gluconeogenesis enzyme such as PEPCK and G-6-Pase enzyme expression in liver tissue of STZ-induced diabetic mice model. Collectively, these findings suggest that EeSs have a high potentiality to mitigate diabetic symptoms through stimulating glucose uptake in peripheral tissue via the activation of AKT and AMPK signaling cascade and augmenting antioxidant potentiality as well as blocking the gluconeogenesis process in diabetic mice.

12.
Innate Immun ; 23(4): 381-391, 2017 05.
Article de Anglais | MEDLINE | ID: mdl-28409541

RÉSUMÉ

The leukocyte Ig-like receptor B4 (LILRB4) is an inhibitory cell surface receptor, primarily expressed on mono-myeloid cells. It contains 2 C-type Ig-like extracellular domains and a long cytoplasmic domain that contains three intracellular immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Data suggest that LILRB4 suppresses Fc receptor-dependent monocyte functions via its ITIMs, but relative contributions of the three ITIMs are not characterised. To address this, tyrosine (Tyr) residues at positions 337, 389 and 419 were single, double or triple mutated to phenylalanine and stably transfected into a human monocytic cell line, THP-1. Intact Tyr389 was sufficient to maximally inhibit FcγRI-mediated TNF-α production in THP-1 cells, but, paradoxically, Tyr337 significantly enhanced TNF-α production. In contrast, bactericidal activity was significantly enhanced in mutants containing Tyr419, while Tyr337 markedly inhibited bacteria killing. Taken together, these results indicate that LILRB4 might have dual inhibitory and activating functions, depending on the position of the functional tyrosine residues in its ITIMs and/or the nature of the stimuli.


Sujet(s)
Monocytes/physiologie , Mutation/génétique , Cellules myéloïdes/physiologie , Domaines protéiques/génétique , Récepteurs de surface cellulaire/métabolisme , Tyrosine/génétique , Bactériolyse/génétique , Lignée cellulaire , Humains , Immunomodulation , Glycoprotéines membranaires , Mutagenèse dirigée , Phosphorylation , Récepteurs de surface cellulaire/génétique , Récepteurs du fragment Fc des IgG/métabolisme , Récepteurs immunologiques , Transduction du signal , Facteur de nécrose tumorale alpha/métabolisme
13.
PLoS One ; 11(2): e0149200, 2016.
Article de Anglais | MEDLINE | ID: mdl-26871720

RÉSUMÉ

Leukocyte immunoglobulin-like receptor A3 (LILRA3) is a soluble immune regulatory molecule primarily expressed by monocytes and macrophages. A homozygous 6.7kbp LILRA3 gene deletion that removes the first seven of its eight exons is predicted to lead to lack of LILRA3 protein, although this has not been experimentally confirmed. Moreover, there are conflicting results with regards to the link between the LILRA3 homozygous genetic deletion and susceptibility to multiple sclerosis (MS) in different European populations. The aim of this study was to investigate whether LILRA3 gene deletion is associated with MS susceptibility in a North American cohort of European ancestry and assess if serum LILRA3 protein level is a marker of clinical subtype and/or disease severity in MS. A total of 456 patients with MS and 99 unrelated healthy controls were genotyped for the 6.7kbp LILRA3 gene deletion and levels of LILRA3 protein in sera determined by in-house sandwich ELISA. We showed that LILRA3 gene deletion was not associated with MS susceptibility and did not affect the age of disease onset, clinical subtype or disease severity. However, we discovered for the first time that homozygous LILRA3 gene deletion results in lack of production of LILRA3 protein. Importantly, LILRA3 protein level was significantly increased in sera of patients with MS when compared with control subjects, particularly in more severe type primary progressive MS. Multiple regression analysis showed that LILRA3 level in serum was one of the strongest independent markers of disease severity in MS, which potentially can be used as a diagnostic marker.


Sujet(s)
Délétion de gène , Sclérose en plaques/sang , Sclérose en plaques/génétique , Récepteurs immunologiques/sang , Récepteurs immunologiques/génétique , Adulte , Études de cohortes , Femelle , Fréquence d'allèle , Humains , Interféron gamma/sang , Interleukine-10/sang , Mâle , Adulte d'âge moyen , Sclérose en plaques/diagnostic , Sclérose en plaques/épidémiologie , Amérique du Nord/épidémiologie , Pronostic , Indice de gravité de la maladie , Facteur de nécrose tumorale alpha/sang , /génétique , Jeune adulte
14.
J Cell Sci ; 129(6): 1198-209, 2016 Mar 15.
Article de Anglais | MEDLINE | ID: mdl-26826187

RÉSUMÉ

Inhibitory proteins, particularly Nogo 66, a highly conserved 66-amino-acid loop of Nogo A (an isoform of RTN4), play key roles in limiting the intrinsic capacity of the central nervous system (CNS) to regenerate after injury. Ligation of surface Nogo receptors (NgRs) and/or leukocyte immunoglobulin-like receptor B2 (LILRB2) and its mouse orthologue the paired immunoglobulin-like receptor B (PIRB) by Nogo 66 transduces inhibitory signals that potently inhibit neurite outgrowth. Here, we show that soluble leukocyte immunoglobulin-like receptor A3 (LILRA3) is a high-affinity receptor for Nogo 66, suggesting that LILRA3 might be a competitive antagonist to these cell surface inhibitory receptors. Consistent with this, LILRA3 significantly reversed Nogo-66-mediated inhibition of neurite outgrowth and promoted synapse formation in primary cortical neurons through regulation of the ERK/MEK pathway. LILRA3 represents a new antagonist to Nogo-66-mediated inhibition of neurite outgrowth in the CNS, a function distinct from its immune-regulatory role in leukocytes. This report is also the first to demonstrate that a member of LILR family normally not expressed in rodents exerts functions on mouse neurons through the highly homologous Nogo 66 ligand.


Sujet(s)
Neurites/métabolisme , Neurones/cytologie , Protéines Nogo/métabolisme , Récepteurs immunologiques/métabolisme , Synapses/métabolisme , Animaux , Cellules cultivées , Humains , Souris , Souris de lignée C57BL , Neurogenèse , Excroissance neuronale , Neurones/métabolisme , Protéines Nogo/génétique , Liaison aux protéines , Récepteurs immunologiques/génétique , Synapses/génétique
15.
J Biol Chem ; 288(46): 32873-85, 2013 Nov 15.
Article de Anglais | MEDLINE | ID: mdl-24085305

RÉSUMÉ

The leukocyte immunoglobulin-like receptor (LILR) A3 is a member of the highly homologous activating and inhibitory receptors expressed on leukocytes. LILRA3 is a soluble receptor of unknown functions but is predicted to act as a broad antagonist to other membrane-bound LILRs. Functions of LILRA3 are unclear primarily because of the lack of high quality functional recombinant protein and insufficient knowledge regarding its ligand(s). Here, we expressed and characterized recombinant LILRA3 (rLILRA3) proteins produced in 293T cells, Escherichia coli, and Pichia pastoris. We found that the purified rLILRA3 produced in the mammalian system was the same size as a 70-kDa native macrophage LILRA3. This is 20 kDa larger than the calculated size, suggesting significant post-translational modifications. In contrast, rLILRA3 produced in E. coli was similar in size to the unprocessed protein, but yeast-produced protein was 2-4 times larger than the unprocessed protein. Treatment with peptide-N-glycosidase F reduced the size of the mammalian cell- and yeast-produced rLILRA3 to 50 kDa, suggesting that most modifications are due to glycosylation. Consistent with this, mass spectrometric analysis of the mammalian rLILRA3 revealed canonical N-glycosylation at the predicted Asn(140), Asn(281), Asn(302), Asn(341), and Asn(431) sites. Functionally, only mammalian cell-expressed rLILRA3 bound onto the surface of monocytes with high affinity, and importantly, only this significantly abrogated LPS-induced TNFα production by monocytes. Binding to monocytes was partially blocked by ß-lactose, indicating that optimally glycosylated LILRA3 might be critical for ligand binding and function. Overall, our data demonstrated for the first time that LILRA3 is a potential new anti-inflammatory protein, and optimal glycosylation is required for its functions.


Sujet(s)
Expression des gènes , Récepteurs immunologiques/biosynthèse , Lignée cellulaire , Femelle , Glycosylation , Humains , Macrophages/cytologie , Macrophages/métabolisme , Mâle , Pichia/génétique , Pichia/métabolisme , Récepteurs immunologiques/composition chimique , Récepteurs immunologiques/génétique , Protéines recombinantes/biosynthèse , Protéines recombinantes/composition chimique , Protéines recombinantes/génétique
16.
Stem Cells Transl Med ; 2(7): 534-44, 2013 Jul.
Article de Anglais | MEDLINE | ID: mdl-23734062

RÉSUMÉ

Retinal degenerations are a major cause of impaired vision in the elderly. Degenerations originate in either photoreceptors or the retinal pigment epithelium (RPE). RPE forms the outer blood-retinal barrier and functions intimately with photoreceptors. Animal models and cultures of RPE are commonly used to screen potential pharmaceuticals or explore RPE replacement therapy, but human RPE differs from that of other species. Human RPE forms a barrier using tight junctions composed of a unique set of claudins, proteins that determine the permeability and selectivity of tight junctions. Human adult RPE fails to replicate these properties in vitro. To develop a culture model for drug development and tissue-engineering human retina, RPE were derived from human embryonic stem cells (hESCs). Barrier properties of RPE derived from the H1 and H9 hESC lines were compared with a well-regarded model of RPE function, human fetal RPE isolated from 16-week-gestation fetuses (hfRPE). A serum-free medium (SFM-1) that enhanced the redifferentiation of hfRPE in culture also furthered the maturation of hESC-derived RPE. In SFM-1, the composition, selectivity, and permeability of tight junctions were similar to those of hfRPE. Comparison of the transcriptomes by RNA sequencing and quantitative reverse transcription-polymerase chain reaction revealed a high correlation between the hESCs and hfRPE, but there were notable differences in the expression of adhesion junction and membrane transport genes. These data indicated that hESC-derived RPE is highly differentiated but may be less mature than RPE isolated from 16-week fetuses. The study identified a panel of genes to monitor the maturation of RPE.


Sujet(s)
Barrière hématorétinienne/cytologie , Cellules souches embryonnaires/cytologie , Épithélium pigmentaire de la rétine/cytologie , Ingénierie tissulaire/méthodes , Transcriptome , Transport biologique/génétique , Barrière hématorétinienne/physiologie , Lignée cellulaire , Cellules cultivées , Claudine-3/génétique , Claudine-3/métabolisme , Cellules souches embryonnaires/physiologie , Foetus/cytologie , Humains , ARN messager/génétique , Épithélium pigmentaire de la rétine/physiologie , RT-PCR , Jonctions serrées/génétique , Jonctions serrées/métabolisme
17.
Ying Yong Sheng Tai Xue Bao ; 22(1): 29-34, 2011 Jan.
Article de Chinois | MEDLINE | ID: mdl-21548284

RÉSUMÉ

Taking the Populus euphratica at lower reaches of Tarim River as test object, and by the methods of tree dendrohydrology, this paper studied the spatiotemporal variation of P. euphratic' s branch radial increment after ecological water transfer. There was a significant difference in the mean radial increment before and after ecological water transfer. The radial increment after the eco-water transfer was increased by 125%, compared with that before the water transfer. During the period of ecological water transfer, the radial increment was increased with increasing water transfer quantity, and there was a positive correlation between the annual radial increment and the total water transfer quantity (R2 = 0.394), suggesting that the radial increment of P. euphratica could be taken as the performance indicator of ecological water transfer. After the ecological water transfer, the radial increment changed greatly with the distance to the River, i.e. , decreased significantly along with the increasing distance to the River (P = 0.007). The P. euphratic' s branch radial increment also differed with stream segment (P = 0.017 ), i.e. , the closer to the head-water point (Daxihaizi Reservoir), the greater the branch radial increment. It was considered that the limited effect of the current ecological water transfer could scarcely change the continually deteriorating situation of the lower reaches of Tarim River.


Sujet(s)
Écosystème , Tiges de plante/croissance et développement , Populus/croissance et développement , Eau/métabolisme , Chine , Populus/métabolisme , Rivières , Mouvements de l'eau
18.
J Rheumatol ; 37(8): 1596-606, 2010 Aug 01.
Article de Anglais | MEDLINE | ID: mdl-20595277

RÉSUMÉ

OBJECTIVE: Leukocyte immunoglobulin-like receptor A3 (LILRA3) belongs to a family of cell-surface receptors with inhibitory or activating functions. LILRA3 lacks transmembrane and cytoplasmic domains, suggesting that it may be secreted. LILRA3 has high homology to activating LILRA1 and A2, hence may act as a soluble agonist/antagonist to these receptors. Individuals lacking the LILRA3 gene have higher incidence of multiple sclerosis and Sjögren's syndrome, suggesting LILRA3 may be antiinflammatory. LILRA3 mRNA was detected in monocytes and mast cells but no protein expression has ever been described. Our aim was to examine LILRA3 protein expression in serum and synovial fluid of patients with rheumatoid arthritis (RA) and determine its in vitro regulation. METHODS: We developed a new ELISA to examine levels of LILRA3 in serum, synovial fluid, and/or culture supernatants from controls and patients with RA, degenerative arthritis, or gout. We used qRT-PCR and flow cytometry to determine the expression and cytokine-mediated regulation of LILRA3. RESULTS: LILRA3 protein is constitutively present in normal serum, with significantly higher concentrations in patients with RA. Serum LILRA3 concentrations from RA patients correlated with disease activity and levels in synovial fluid. Treatment of monocytes with interleukin 10 or interferon-gamma significantly upregulated while tumor necrosis factor-alpha significantly downregulated LILRA3 mRNA and protein expression. CONCLUSION: We show for the first time that LILRA3 is significantly increased in serum of patients with RA and is tightly regulated by key cytokines involved in pathogenesis of RA. These results suggest that LILRA3 may play a role in chronic inflammatory conditions such as RA.


Sujet(s)
Polyarthrite rhumatoïde/sang , Interféron gamma/sang , Interleukine-10/sang , Récepteurs immunologiques/sang , Facteur de nécrose tumorale alpha/sang , Adulte , Sujet âgé , Polyarthrite rhumatoïde/physiopathologie , Cellules cultivées , Test ELISA , Femelle , Expression des gènes/effets des médicaments et des substances chimiques , État de santé , Humains , Interféron gamma/pharmacologie , Interleukine-10/pharmacologie , Mâle , Mastocytes/effets des médicaments et des substances chimiques , Mastocytes/métabolisme , Adulte d'âge moyen , Monocytes/effets des médicaments et des substances chimiques , Monocytes/métabolisme , ARN messager/métabolisme , Récepteurs immunologiques/analyse , Récepteurs immunologiques/génétique , Indice de gravité de la maladie , Synovie/composition chimique , Facteur de nécrose tumorale alpha/pharmacologie , Régulation positive/effets des médicaments et des substances chimiques
19.
Infect Immun ; 71(8): 4516-25, 2003 Aug.
Article de Anglais | MEDLINE | ID: mdl-12874331

RÉSUMÉ

Nonenterotoxigenic porcine Escherichia coli strains belonging to the serogroup O45 have been associated with postweaning diarrhea in swine and adhere to intestinal epithelial cells in a characteristic attaching and effacing (A/E) pattern. O45 porcine enteropathogenic E. coli (PEPEC) strain 86-1390 induces typical A/E lesions in a pig ileal explant model. Using TnphoA transposon insertion mutagenesis on strain 86-1390, we found a mutant that did not induce A/E lesions. The insertion was identified in a gene designated paa (porcine A/E-associated gene). Sequence analysis of paa revealed an open reading frame of 753 bp encoding a 27.6-kDa protein which displayed 100, 51.8, and 49% homology with Paa of enterohemorrhagic E. coli O157:H7 strains (EDL933 and Sakai), PEB3 of Campylobacter jejuni, and AcfC of Vibrio cholerae, respectively. Chromosomal localization studies indicated that the region containing paa was inserted between the yciD and yciE genes at about 28.3 min of the E. coli K-12 chromosome. The presence of paa and eae sequences in the porcine O45 strains is highly correlated with the A/E phenotype. However, the observation that three eae-positive but paa-negative PEPEC O45 strains were A/E negative provides further evidence for the importance of the paa gene in the A/E activity of O45 strains. As well, the complementation of the paa mutant restored the A/E activity of the 86-1390 strain, showing the involvement of Paa in PEPEC pathogenicity. These observations suggest that Paa contributes to the early stages of A/E E. coli virulence.


Sujet(s)
Adhésines d'Escherichia coli/physiologie , Adhérence bactérienne/physiologie , Escherichia coli/physiologie , Escherichia coli/pathogénicité , Adhésines d'Escherichia coli/génétique , Allèles , Séquence d'acides aminés , Animaux , Anticorps antibactériens/pharmacologie , Adhérence bactérienne/génétique , Séquence nucléotidique , Cartographie chromosomique , Chromosomes de bactérie/génétique , ADN bactérien/génétique , Escherichia coli/génétique , Escherichia coli/ultrastructure , Gènes bactériens , Test de complémentation , Muqueuse intestinale/microbiologie , Microscopie électronique , Données de séquences moléculaires , Mutagenèse par insertion , Phénotype , Similitude de séquences d'acides aminés , Sus scrofa
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