Original article
An amebic anti-inflammatory peptide down-regulates ex vivo IL-1β expression in patients with rheumatoid arthritis
Un péptido antiinflamatorio amibiano disminuye en pacientes con artritis reumatoide la expresión ex vivo de IL-1β
Juan R. Velázqueza,
, Lizeth Garibay-Martínezb, Pedro Martínez-Tejadac, Yelda A. Leald
Autor para correspondencia
a Departamento de Inmunogénetica y Alergia, INER, México, D.F., Mexico
b Unidad de Investigación Médica Zacatecas, IMSS, Zacatecas, Zacatecas, Mexico
c Hospital Dr. Emilio Varela-Luján, IMSS, Zacatecas, Zacatecas, Mexico
d Unidad de Investigación Médica Yucatán (UIMY), Unidad Médica de Alta Especialidad de Mérida “Dr. Ignacio García Tellez”, IMSS, Mérida, Yucatán, Mexico
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Triplicate cultures of 4<span class="elsevierStyleHsp" style=""></span>×<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleSup">6</span> U-937 cells in the presence of MLIF, LPS or both were harvested at 0.3, 1, 2, 4, 6, 8 and 10<span class="elsevierStyleHsp" style=""></span>h. RNA was obtained from pellets and used for real time PCR. Comparative expression was established using unstimulated cells as reference. LPS induced a strong up-regulation of IL-1β which peaks at 4<span class="elsevierStyleHsp" style=""></span>h. MLIF <span class="elsevierStyleItalic">per se</span> did not affect IL-1β basal expression but MLIF was able to reduce significantly the stimulatory effect of LPS when amebic peptide was added simultaneously to LPS (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.05). 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"documento" => "article" "crossmark" => 0 "subdocumento" => "fla" "cita" => "Reumatol Clin. 2012;8:321-7" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 5464 "formatos" => array:3 [ "EPUB" => 191 "HTML" => 3752 "PDF" => 1521 ] ] "es" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Original</span>" "titulo" => "Análisis del polimorfismo rs20541 (R130Q) del gen de la IL-13 en pacientes con enfermedades inflamatorias crónicas asociadas al envejecimiento" "tienePdf" => "es" "tieneTextoCompleto" => "es" "tieneResumen" => array:2 [ 0 => "es" 1 => "en" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "321" "paginaFinal" => "327" ] ] "titulosAlternativos" => array:1 [ "en" => array:1 [ "titulo" => "Analysis of the rs20541 (R130Q) polymorphism in the IL-13 gene in patients with elderly-associated chronic inflammatory diseases" ] ] "contieneResumen" => array:2 [ "es" => true "en" => true ] "contieneTextoCompleto" => array:1 [ "es" => true ] "contienePdf" => array:1 [ "es" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0020" "etiqueta" => "Figura 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 1409 "Ancho" => 1409 "Tamanyo" => 43796 ] ] "descripcion" => array:1 [ "es" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">Concentración sérica de IL-13 en función del SNP R130Q en el gen de la IL-13. Los datos se representan de forma conjunta para los pacientes con enfermedad activa de las tres patologías incluidas en el estudio (N.° total=114: arteritis de células gigantes [ACG; N = 15], polimialgia reumática [PMR; N =71] y artritis reumatoide de inicio en el anciano [EORA; N = 28]).</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Lorena Álvarez-Rodríguez, Marcos López-Hoyos, Eugenio Carrasco-Marín, Cristina Mata, Jaime Calvo-Alén, Elena Aurrecoechea, Ricardo Blanco, Teresa Ruiz, Pedro Muñoz Cacho, Ignacio Villa, Víctor Manuel Martínez-Taboada" "autores" => array:11 [ 0 => array:2 [ "nombre" => "Lorena" "apellidos" => "Álvarez-Rodríguez" ] 1 => array:2 [ "nombre" => "Marcos" "apellidos" => "López-Hoyos" ] 2 => array:2 [ "nombre" => "Eugenio" "apellidos" => "Carrasco-Marín" ] 3 => array:2 [ "nombre" => "Cristina" "apellidos" => "Mata" ] 4 => array:2 [ "nombre" => "Jaime" "apellidos" => "Calvo-Alén" ] 5 => array:2 [ "nombre" => "Elena" "apellidos" => "Aurrecoechea" ] 6 => array:2 [ "nombre" => "Ricardo" "apellidos" => "Blanco" ] 7 => array:2 [ "nombre" => "Teresa" "apellidos" => "Ruiz" ] 8 => array:2 [ "nombre" => "Pedro" "apellidos" => "Muñoz Cacho" ] 9 => array:2 [ "nombre" => "Ignacio" "apellidos" => "Villa" ] 10 => array:2 [ "nombre" => "Víctor Manuel" "apellidos" => "Martínez-Taboada" ] ] ] ] ] "idiomaDefecto" => "es" "Traduccion" => array:1 [ "en" => array:9 [ "pii" => "S2173574312000962" "doi" => "10.1016/j.reumae.2012.07.003" "estado" => "S300" "subdocumento" => "" "abierto" => array:3 [ "ES" => false "ES2" => false "LATM" => false ] "gratuito" => false "lecturas" => array:1 [ "total" => 0 ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2173574312000962?idApp=UINPBA00004M" ] ] "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1699258X12001325?idApp=UINPBA00004M" "url" => "/1699258X/0000000800000006/v1_201305061930/S1699258X12001325/v1_201305061930/es/main.assets" ] "itemAnterior" => array:19 [ "pii" => "S1699258X12000848" "issn" => "1699258X" "doi" => "10.1016/j.reuma.2012.03.004" "estado" => "S300" "fechaPublicacion" => "2012-11-01" "aid" => "438" "copyright" => "Elsevier España, S.L." 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Velázquez, Lizeth Garibay-Martínez, Pedro Martínez-Tejada, Yelda A. Leal" "autores" => array:4 [ 0 => array:4 [ "nombre" => "Juan R." "apellidos" => "Velázquez" "email" => array:1 [ 0 => "velazquez_juan@hotmail.com" ] "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">¿</span>" "identificador" => "cor0005" ] ] ] 1 => array:3 [ "nombre" => "Lizeth" "apellidos" => "Garibay-Martínez" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] ] ] 2 => array:3 [ "nombre" => "Pedro" "apellidos" => "Martínez-Tejada" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0015" ] ] ] 3 => array:3 [ "nombre" => "Yelda A." "apellidos" => "Leal" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0020" ] ] ] ] "afiliaciones" => array:4 [ 0 => array:3 [ "entidad" => "Departamento de Inmunogénetica y Alergia, INER, México, D.F., Mexico" "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:3 [ "entidad" => "Unidad de Investigación Médica Zacatecas, IMSS, Zacatecas, Zacatecas, Mexico" "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] 2 => array:3 [ "entidad" => "Hospital Dr. Emilio Varela-Luján, IMSS, Zacatecas, Zacatecas, Mexico" "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0015" ] 3 => array:3 [ "entidad" => "Unidad de Investigación Médica Yucatán (UIMY), Unidad Médica de Alta Especialidad de Mérida “Dr. Ignacio García Tellez”, IMSS, Mérida, Yucatán, Mexico" "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0020" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "⁎" "correspondencia" => "Corresponding author." ] ] ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Un péptido antiinflamatorio amibiano disminuye en pacientes con artritis reumatoide la expresión <span class="elsevierStyleItalic">ex vivo</span> de IL-1β" ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0015" "etiqueta" => "Figure 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 1620 "Ancho" => 2222 "Tamanyo" => 148002 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">Effect of MLIF in PBMC from healthy and patients with RA. Healthy donors (<span class="elsevierStyleItalic">n</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>13) and patients with RA (<span class="elsevierStyleItalic">n</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>11) PBMC were cultured during 4<span class="elsevierStyleHsp" style=""></span>h in the presence of LPS, MLIF or both. qPCR analysis for IL-1β transcripts was carried out in each case and comparison between groups established by a normalized expression ratio (ner). (a) Patients with AR constitutively express more IL-1β than healthy donors. IL-1β ner between them was statistically different (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.03). (b) MLIF shows a down-regulatory effect on IL-1β expression in patients with RA which ner is <1 in 91% of cases (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.01). (c) Capacity of LPS to up-regulate IL-1β in both healthy donors and patients with RA was not significantly different. (d) MLIF was able to down-regulate LPS-induction in all patients with RA (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.001).</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleItalic">Entamoeba histolytica</span> produces a heat-stable pentapeptide (Met-Gln-Cys-Asp-Ser, MQCNS) that was originally identified by its effects in delaying mononuclear phagocytes migration to inflammation sites. This peptide was hereby denominated by the MLIF and was shown to have several anti-inflammatory properties.<a class="elsevierStyleCrossRef" href="#bib0005"><span class="elsevierStyleSup">1</span></a><span class="elsevierStyleItalic">In vitro</span>, it inhibits induction of macrophage inflammatory proteins (MIP-1α, -1β), IL-1β, IL-8, and chemokine CCL1 (I-309), and the chemokine receptor 1 (CCR1) in phorbol myristate acetate (PMA)-stimulated promonocytic human cell line (U-937) cells.<a class="elsevierStyleCrossRefs" href="#bib0010"><span class="elsevierStyleSup">2,3</span></a> In umbilical vein endothelial cells (UVEC), MLIF reduces vascular cell adhesion molecule (VCAM)-1 and E-selectin expression (personal communication). <span class="elsevierStyleItalic">In vivo</span> it delays mononuclear cells migration to the inflammatory focus in human skin1. The peptide is able to inhibit expression of cell adhesion molecules very late antigen (VLA)-4 and VCAM-1 in a dinitrochlorobenzene (DNCB)-hypersensitivity, guinea pig model.<a class="elsevierStyleCrossRef" href="#bib0020"><span class="elsevierStyleSup">4</span></a> In U-937 cells and in the CIA model, analysis of gene expression profiles employing microarrays reveals a regulatory capacity of MLIF on numerous inflammatory genes including IL-1β.<a class="elsevierStyleCrossRef" href="#bib0010"><span class="elsevierStyleSup">2</span></a> In addition, the amebic peptide has exhibited a notorious anti-inflammatory effect in carragenin-induced inflammation model in BALB/c mice (personal communication). The MLIF molecular mechanisms of action are poorly understood; however, there is evidence of its involvement in nuclear factor-kappa B (NF-κB) signal transduction; MLIF appears to induce nuclear translocation of p50 homodimers, affecting a number of inflammatory transcripts.<a class="elsevierStyleCrossRef" href="#bib0025"><span class="elsevierStyleSup">5</span></a></p><p id="par0010" class="elsevierStylePara elsevierViewall">RA is a multisystemic chronic disease of unknown etiology. During its development, there are periods of activity and reminiscence that could be diagnosed on the basis of a battery of clinical and laboratory tests.<a class="elsevierStyleCrossRefs" href="#bib0030"><span class="elsevierStyleSup">6,7</span></a> One hallmark of RA is the inflammatory process that occurs in the joint. The resulting inflammatory response induced by pro-inflammatory cytokines (mainly tumor necrosis factor [TNF]α and IL-1β) leads to synovial fibroblast hyperplasia, increased vascularity, and inflammatory cell infiltrate.<a class="elsevierStyleCrossRefs" href="#bib0040"><span class="elsevierStyleSup">8–10</span></a> Messenger RNA (mRNA) and protein analysis of patients with RA has shown abundant expression of IL-1β and TNFα cytokines.<a class="elsevierStyleCrossRefs" href="#bib0055"><span class="elsevierStyleSup">11,12</span></a> In this work we tested the effect of anti-inflammatory peptide MLIF upon the constitutive and LPS-induced synthesis of IL-1β in U-937 and PBMC from healthy subjects and from patients with RA.</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Materials and methods</span><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Cells</span><p id="par0015" class="elsevierStylePara elsevierViewall">The promonocytic human cell line U-937 (American Type Culture Collection, ATCC, Manassas, VA, USA) was propagated in RPMI-1640 endotoxin-free medium (In vitro, Life Technologies, Eggenstein, Germany) supplemented with 2<span class="elsevierStyleHsp" style=""></span>mM <span class="elsevierStyleSmallCaps">l</span>-glutamine, 1.5<span class="elsevierStyleHsp" style=""></span>g/L sodium bicarbonate, 4.5<span class="elsevierStyleHsp" style=""></span>g/L <span class="elsevierStyleSmallCaps">d</span>-glucose, 10<span class="elsevierStyleHsp" style=""></span>mM HEPES, 1.0<span class="elsevierStyleHsp" style=""></span>mM sodium pyruvate and 10% heat-inactivated, endotoxin-free fetal bovine serum (FBS, Gibco BRL Life Technologies, Grand Island, NY, USA). Cells were maintained at 37<span class="elsevierStyleHsp" style=""></span>°C in a humidified atmosphere with 5% CO<span class="elsevierStyleInf">2</span>. PBMC were obtained from healthy individuals or patients with AR by Böyum method.<a class="elsevierStyleCrossRef" href="#bib0065"><span class="elsevierStyleSup">13</span></a> Briefly, 4<span class="elsevierStyleHsp" style=""></span>mL of diluted blood sample was carefully layered on 3<span class="elsevierStyleHsp" style=""></span>mL of Ficoll-Paque PLUS (GE Heathcare Bio-Sciences Corp, Piscatawa, NJ, USA), tubes were centrifuged at 400<span class="elsevierStyleHsp" style=""></span>×<span class="elsevierStyleHsp" style=""></span><span class="elsevierStyleItalic">g</span> for 30<span class="elsevierStyleHsp" style=""></span>min at room temperature. Using a Pasteur pipette we take off the mononuclear layer and washed it with balanced salt solution. Typically recovered cells were ≥95% mononuclear cells with ≥95% viability.</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Cultures</span><p id="par0020" class="elsevierStylePara elsevierViewall">Time-course experiments were carried out in triplicate groups of 4<span class="elsevierStyleHsp" style=""></span>×<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleSup">6</span><span class="elsevierStyleHsp" style=""></span>mL<span class="elsevierStyleSup">−1</span>. U-937 cells incubated at 37<span class="elsevierStyleHsp" style=""></span>°C in a humidified atmosphere with 5% CO<span class="elsevierStyleInf">2</span> during 0–10<span class="elsevierStyleHsp" style=""></span>h were treated as follows: (a) in RPMI-1640 medium alone (unstimulated); (b) MLIF (50<span class="elsevierStyleHsp" style=""></span>g/mL) added (<span class="elsevierStyleItalic">per se</span> effect); (c) LPS (10 ng/mL) added (induced expression), and (d) MLIF and LPS added simultaneously (interference). After 0.3, 1, 2, 4, 6, 8 and 10<span class="elsevierStyleHsp" style=""></span>h, cells were harvested by centrifugation. All cell pellets were used for RNA isolation, and 4, 6 and 8<span class="elsevierStyleHsp" style=""></span>h supernatant fluids employed for IL-1β immunoreactivity. Triplicate groups of 4<span class="elsevierStyleHsp" style=""></span>×<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleSup">6</span><span class="elsevierStyleHsp" style=""></span>mL<span class="elsevierStyleSup">−1</span> human PBMC were incubated during 4 and 6<span class="elsevierStyleHsp" style=""></span>h without stimulus, MLIF, LPS or both. After 4<span class="elsevierStyleHsp" style=""></span>h, the cell pellet (for RNA isolation) or after 6<span class="elsevierStyleHsp" style=""></span>h, the supernatant fluid (for IL-1β immunoreactivity) was harvested by centrifugation. At the conclusion of all experiments, cell viability was ≥90% by trypan blue dye (Sigma Chemical Co., St. Louis, MO) exclusion. The concentration of MLIF employed in these studies was based on previous <span class="elsevierStyleItalic">in vitro</span> functional experiments.<a class="elsevierStyleCrossRefs" href="#bib0010"><span class="elsevierStyleSup">2,3</span></a> Simultaneous addition of MLIF to assays was employed, because pilot studies have revealed that MLIF mainly affected cytokine induction when added prior to (weak) or simultaneously (strong), but less after LPS stimulation.</p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Chemical substances</span><p id="par0025" class="elsevierStylePara elsevierViewall">A single batch, 96% pure MLIF (Met-Gln-Cys-Asp-Ser, MQCNS) endotoxin-free sample was commercially obtained (American Peptide Co., Sunnyvale, CA, USA). MLIF was dissolved in sterile PBS and tested for endotoxin activity using Limulus amoebocyte lysate KTA (Charles River Endosafe Inc., Charleston, SC, USA). Endotoxin activity was ≤0.0625<span class="elsevierStyleHsp" style=""></span>UIE<span class="elsevierStyleHsp" style=""></span>mL/endotoxin. LPS <span class="elsevierStyleItalic">Escherichia coli</span> serotype 0111:B4 was obtained from Sigma.</p></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Subjects</span><p id="par0030" class="elsevierStylePara elsevierViewall">Females, 35–59 years of age, were recruited from the Blood Bank (healthy donors) and Rheumatology Clinic of “Dr. Emilio Varela-Lujan” General Hospital, Mexican Institute of Social Security (IMSS) in Zacatecas City, Mexico. Patients with RA were classified as such when they fulfilled four or more American College of Rheumatology (ACR) criteria. Subjects were under Anti-inflammatory non-steroid treatment (AINES), or glucocorticoids at doses ≤10<span class="elsevierStyleHsp" style=""></span>mg/day and were free of biologic therapy (anti-TNFα, anti-IL-1β or anti CD20) at least 6 months prior to the study. The study included 13 healthy subjects and 11 patients with RA. All study participants gave written informed consent to participate in the study. The procedure complies with the international ethics for human research and was approved by the Dr. Emilio Varela Luján Hospital Ethics Committee.</p></span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">RNA extraction and reverse transcription</span><p id="par0035" class="elsevierStylePara elsevierViewall">Total RNA was extracted using TRIzol (Invitrogen, Carlsbad, CA, USA) as described.<a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> RNA purity was established in 2.5% denaturing agarose gels, and the concentration determined in a NanoDrop<span class="elsevierStyleSup">®</span> ND-1000 spectrophotometer (Thermo Scientific Inc., Wilmington, DE, USA). For reverse transcription, 1<span class="elsevierStyleHsp" style=""></span>μg of total RNA was mixed with 1<span class="elsevierStyleHsp" style=""></span>μL oligo-dT (12–18-mer, Invitrogen), 200<span class="elsevierStyleHsp" style=""></span>U SuperScript™ reverse transcriptase (Invitrogen), 1× First Stand Buffer (Invitrogen), and 0.5<span class="elsevierStyleHsp" style=""></span>mM mixed dNTPs (dATP, dCTP, dGTP, dTTP) (Promega, Co., Madison, WI, USA). The mixture was incubated at 42<span class="elsevierStyleHsp" style=""></span>°C for 1<span class="elsevierStyleHsp" style=""></span>h. Reverse transcription was heat-inactivated at 80<span class="elsevierStyleHsp" style=""></span>°C for 10<span class="elsevierStyleHsp" style=""></span>min and the resulting cDNA was employed for real-time polymerase chain reaction (PCR).</p></span><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Real-time polymerase chain reaction analysis</span><p id="par0040" class="elsevierStylePara elsevierViewall">Real-time PCR was performed in capillaries in a 20<span class="elsevierStyleHsp" style=""></span>μL reaction mix containing Light Cycler Taqman (Roche Applied Science, Salt Lake City, UT, USA), 0.2<span class="elsevierStyleHsp" style=""></span>μM specific primer mix, and 0.1<span class="elsevierStyleHsp" style=""></span>μM of gene-specific hydrolysis probes from the Universal Probe Library (Roche) and cDNA. PCR reaction included 45 cycles consisting of denaturation at 95<span class="elsevierStyleHsp" style=""></span>°C for 10<span class="elsevierStyleHsp" style=""></span>s, annealing at 60<span class="elsevierStyleHsp" style=""></span>°C for 20<span class="elsevierStyleHsp" style=""></span>s, and extension at 72<span class="elsevierStyleHsp" style=""></span>°C for 1<span class="elsevierStyleHsp" style=""></span>s. All reactions were performed in a LightCycler 2.0 instrument (Roche) and data analysis was conducted with LightCycler software 4.05 (Roche).</p><p id="par0045" class="elsevierStylePara elsevierViewall">We obtained the relative expression of IL-1β induced by LPS, MLIF and LPS<span class="elsevierStyleHsp" style=""></span>+<span class="elsevierStyleHsp" style=""></span>MLIF with respect to unstimulated cells using the ΔΔCP method.<a class="elsevierStyleCrossRef" href="#bib0070"><span class="elsevierStyleSup">14</span></a> Briefly, we copied the CP values for each sample in an Excel spreadsheet, the first delta CP was calculated from IL-1β CP minus glyceraldehyde 3-phosphate dehydrogenase (GAPDH) CP for each sample accordingly. Deltadelta CP for each condition was equal to stimulated sample delta CP minus unstimulated sample CP. Relative expression was calculated using Relative expression<span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>2<span class="elsevierStyleSup">(−deltadelta CP)</span> formula.</p><p id="par0050" class="elsevierStylePara elsevierViewall">We considered IL-1β as target gene and GAPDH as housekeeping gene.</p><p id="par0055" class="elsevierStylePara elsevierViewall">For comparison among study groups (healthy subjects <span class="elsevierStyleItalic">vs</span> patients with RA), real-time PCR calibration curves for IL-1β and GAPDH genes were produced from purified specific amplicons. In all groups we obtained normalized expression ratio (ner) of each condition (unstimulated, LPS, MLIF and LPS<span class="elsevierStyleHsp" style=""></span>+<span class="elsevierStyleHsp" style=""></span>MLIF) employing the formula:<elsevierMultimedia ident="eq0005"></elsevierMultimedia></p><p id="par0060" class="elsevierStylePara elsevierViewall">Comparison among different ner was used to evaluate basal IL-1β, and responses induced by LPS and MLIF, as well as MLIF capacity to antagonize LPS response.</p></span><span id="sec0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Enzyme-linked immunoabsorbent assays</span><p id="par0065" class="elsevierStylePara elsevierViewall">IL-1β proteins in supernatant fluids were measured using a commercial ELISA kit DuoSet<span class="elsevierStyleSup">®</span> (R & D Systems, Inc., Minneapolis, MN, USA). Plates were incubated overnight at 4<span class="elsevierStyleHsp" style=""></span>°C, washed and blocked. Final development employed ExtrAvidin™ HRP and substrate 3,3′,5,5′-tetramethyl-benzidine (Sigma). Microtiter plates were read at 450<span class="elsevierStyleHsp" style=""></span>nm in a BIO-RAD microplate Benchmark densitometer (Richmond, CA, USA). Results were expressed as ng/mL. Sensitivity for IL-1β was ≥2<span class="elsevierStyleHsp" style=""></span>pg/mL.</p></span><span id="sec0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Statistical analysis</span><p id="par0070" class="elsevierStylePara elsevierViewall">Results are expressed as mean ranks. Statistical significance of differences in mean values between different groups was evaluated by Kruskal–Wallis test, followed by <span class="elsevierStyleItalic">U</span>-Mann–Whitney test for inter-group comparisons. A value of <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.05 was considered to be significant. All analyses were performed with SPSS software version 15.0 (SPSS Inc., Chicago, IL).</p></span></span><span id="sec0055" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Results</span><span id="sec0060" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Cellular response to lipopolysaccharide and the antagonist effect of monocyte locomotion inhibitory factor</span><p id="par0075" class="elsevierStylePara elsevierViewall">Previous work utilizing U-937 demonstrated that MLIF was able to decrease PMA-induced expression of chemokines MIP-1α and MIP-1β, as well as that of cytokine IL-1β.<a class="elsevierStyleCrossRefs" href="#bib0010"><span class="elsevierStyleSup">2,3</span></a> We observed this effect only when the peptide was administered prior to or simultaneously with the activator agent. The neutralizing effect of MLIF on such an event was outstanding, if we take into account that PMA is a powerful cell activator that disrupts several cell signaling pathways. On the other hand, because MLIF is involved in the NF-κB signaling, we were interested in observing the amebic peptide effect on the production of LPS/TLR4 signaling-dependent IL-1β.</p><p id="par0080" class="elsevierStylePara elsevierViewall">In a triplicate time-course experiment using U-937 cells, LPS-induced expression of IL-1β was followed with real-time PCR. Specific IL-1β mRNA was detected in a 1–10<span class="elsevierStyleHsp" style=""></span>h window of time (<a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>). Maximum response to LPS peaked at 4<span class="elsevierStyleHsp" style=""></span>h post-stimulation with 94<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.15 (mean<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>SEM) folds, and afterwards there was a symmetrically decreasing production. When MLIF was administrated simultaneously with LPS, the amebic peptide exhibited an astonishing antagonist effect at 4<span class="elsevierStyleHsp" style=""></span>h (relative expression 94<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.15-fold with LPS <span class="elsevierStyleItalic">vs</span> 8<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.03-fold with LPS<span class="elsevierStyleHsp" style=""></span>+<span class="elsevierStyleHsp" style=""></span>MLIF (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.05)). On the other hand, amebic peptide <span class="elsevierStyleItalic">per se</span> showed no IL-1β regulatory capacity.</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia></span><span id="sec0065" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Immunoreactivity of lipopolysaccharide-induced interleukin-1β</span><p id="par0085" class="elsevierStylePara elsevierViewall">Supernatants from mentioned triplicate experiment were used for measuring IL-1β immunoreactivity released by U-937 cells stimulated with LPS, MLIF or both at three different times (4, 6, and 8<span class="elsevierStyleHsp" style=""></span>h). A higher amount of IL-1β was detected after 6<span class="elsevierStyleHsp" style=""></span>h of incubation where LPS-induction was maximum with 18.5<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.74<span class="elsevierStyleHsp" style=""></span>pg/mL, statistical difference between LPS <span class="elsevierStyleItalic">vs</span> MLIF (18.5<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.4 <span class="elsevierStyleItalic">vs</span> 13.2<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.4), and LPS <span class="elsevierStyleItalic">vs</span> unstimulated cells (18.5<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.4 <span class="elsevierStyleItalic">vs</span> 9.6<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>0.5) was significant with <span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span><<span class="elsevierStyleHsp" style=""></span>0.05 for both. MLIF showed no effect on IL-1β release by LPS stimulation. At 4 and 8<span class="elsevierStyleHsp" style=""></span>h IL-1β response to LPS was poor, and in most conditions immunoreactivity was near the assay detection limit (<a class="elsevierStyleCrossRef" href="#fig0010">Fig. 2</a>). There is a trend for MLIF to interfere with LPS effect at 4<span class="elsevierStyleHsp" style=""></span>h and 8<span class="elsevierStyleHsp" style=""></span>h but statistics showed it not to be significant. Once again, the peptide <span class="elsevierStyleItalic">per se</span> did not affect the production of IL-1β.</p><elsevierMultimedia ident="fig0010"></elsevierMultimedia></span><span id="sec0070" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Monocyte locomotion inhibitory factor effect on immunocompetent cells</span><p id="par0090" class="elsevierStylePara elsevierViewall">We were interested in testing the observed MLIF effects in differentiated immunocompetent cells. PBMC cultures from healthy subjects and patients with RA were used to look at basal expression of IL-1β. As expected, patients with RA exhibited higher expression of IL-1β mRNA in comparison with healthy subjects. 91% of patients with RA (10 of 11 patients) IL-1β ner was >1; meanwhile in 54% of healthy subjects (9 of 13) IL-1β ner was >1 (<a class="elsevierStyleCrossRef" href="#fig0015">Fig. 3</a>a). Statistical data showed a significantly higher expression of IL-1β in patients with RA compared with healthy donors (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.03).</p><elsevierMultimedia ident="fig0015"></elsevierMultimedia><p id="par0095" class="elsevierStylePara elsevierViewall">The capacity of MLIF to affect the expression of IL-1β was determined as the ratio of MLIF ner to unstimulated ner. The presence of MLIF in PBMC cultures decreased IL-1β expression (ratio <1) in 91% of patients with AR (10 of 11) and in 46% of healthy donors (6 of 13) (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.01) (<a class="elsevierStyleCrossRef" href="#fig0015">Fig. 3</a>b).</p><p id="par0100" class="elsevierStylePara elsevierViewall">Ratios of LPS-induced ner to unstimulated ner were employed to evaluate LPS stimulatory capacity in PBMC cultures. We considered an increase of >2-folds in IL-1β expression as a biologically effective criterion. Studied groups responded in similar fashion to LPS stimulus; 64% (7 of 11) patients with RA and 62% (8 of 13) healthy donors responded to LPS, and no significant differences were found among them (<a class="elsevierStyleCrossRef" href="#fig0015">Fig. 3</a>c).</p><p id="par0105" class="elsevierStylePara elsevierViewall">We considered that MLIF could antagonize with LPS when ratios of LPS<span class="elsevierStyleHsp" style=""></span>+<span class="elsevierStyleHsp" style=""></span>MLIF ner to LPS-induced ner were <1. Expression of IL-1β decreased in 100% (11 of 11) of patients with RA and in 38% (5 of 13) of healthy subjects (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.001) (<a class="elsevierStyleCrossRef" href="#fig0015">Fig. 3</a>d).</p></span><span id="sec0075" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Inmunoreactivity of interleukin-1β in peripheral blood mononuclear cells</span><p id="par0110" class="elsevierStylePara elsevierViewall">IL-1β inmunoreactivity in PBMC cultures was in general low (below the detection limit in the majority of cases). It was only possible to detect IL-1β in 36% (4 of 11) of patients with RA and in 8% (1 of 13) of healthy donors. Apparently, RA group releases more IL-1β than healthy group (18<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>2.1 <span class="elsevierStyleItalic">vs</span> 8<span class="elsevierStyleHsp" style=""></span>±<span class="elsevierStyleHsp" style=""></span>1.6<span class="elsevierStyleHsp" style=""></span>pg/mL, respectively). However, because the low number of data, no significant differences were found between them. In the group of patients with RA, we observed a MLIF trend to diminish the amount of IL-1β spontaneously released in culture from 18.0 to 5.1<span class="elsevierStyleHsp" style=""></span>pg/mL, as well as an antagonist effect on LPS-stimulation in both RA and healthy groups (from 14.6 to 9.0; and from 19.2 to 7.1<span class="elsevierStyleHsp" style=""></span>pg/mL, respectively) (<a class="elsevierStyleCrossRef" href="#fig0020">Fig. 4</a>). This result is interesting but not conclusive due the low number of immunoreactive samples.</p><elsevierMultimedia ident="fig0020"></elsevierMultimedia></span></span><span id="sec0080" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Discussion</span><p id="par0115" class="elsevierStylePara elsevierViewall">Several studies have shown the MLIF modulatory capacity on inflammatory genes. The antagonist effect of the amebic peptide when administered prior to or simultaneously with LPS appears to involve it in early signaling events linked with either putative or non- putative membrane receptors.<a class="elsevierStyleCrossRef" href="#bib0025"><span class="elsevierStyleSup">5</span></a> Data on LPS activation by means of TLR4 in U-937 cells had revealed that MLIF is able to interfere with MyD88 membrane recruitment in response to LPS, thus affecting an array of MyD88-dependent genes 5. Ongoing studies in our laboratory with respect to IL-1β synthesis utilizing U-937 cells have shown that MLIF increase the degradation of specific mRNA when induced with LPS. The use of ERK, JNK, p38 and NF-κB inhibitors have brought to light the participation of a NF-κB inhibitory dimmer induced by MLIF that is perhaps responsible for abrogating IL-1β transcription and participating in a cross-talk between NF-κB and mitogen-activated protein kinase (MAPK) signaling cascades. Differential expression profiles of U-937 stimulated with PMA demonstrated a remarkable interfering capacity of MLIF on induced transcription of IL-1β. In this report when using U-937 cells, we found that MLIF <span class="elsevierStyleItalic">per se</span> did not affect IL-1β expression, but that it indeed interferes with LPS in a narrow window of time. MLIF shows no capacity in regulating the LPS-induced immunoreactivity of IL-1β in U-937 cells; however, it is important to consider the poor response of these cells to LPS. Regulation of MLIF on IL-1β transcripts but not on IL-1β protein of U-937 cells could be due to genetic alterations in the cell line, lack of synchronicity in the synthesis, storage, and further secretion of mature IL-1β. Assessment of IL-1β requires the presence in the medium of inmunoreactive cytokine which is generated in a cyclic and complicated process. The immunoreactivity detected is closely related with the cell's ability to generate and to secrete caspase-1-processed IL-1β. Clearly, additional studies on the extracellular bioavailability and intracellular storage of IL-1β in stimulated cells in the presence of MLIF are required.</p><p id="par0120" class="elsevierStylePara elsevierViewall">On the other hand, the effect of MLIF on primed cells is slightly different in immunocompetent PBMC from an inflammatory environment such as RA. In arthritic PBMC, there is an over-expression of basal IL-1β, which is in agreement with other reports.<a class="elsevierStyleCrossRef" href="#bib0075"><span class="elsevierStyleSup">15</span></a> MLIF down-regulated IL-1β basal expression and interfered with LPS-induction. IL-1β immunoreactivity levels in PBMC culture supernatants exhibited in general a lower detection limit, but in the few subjects with detected activity MLIF acted mainly on patients with RA, decreasing spontaneous release of IL-1β and interfering with LPS-induction. An increased number of subjects would aid in clarifying this issue.</p><p id="par0125" class="elsevierStylePara elsevierViewall">We are not certain about MLIF action only in transcription but not in translation of IL-1β. For example, we have evidence that administration of the amebic peptide in a CIA model ameliorates the inflammation process and modulates gene expression profiles (IL-1β included among other dozens of genes).<a class="elsevierStyleCrossRef" href="#bib0080"><span class="elsevierStyleSup">16</span></a> Furthermore, MLIF is able to reduce the immunoreactivity of IL-1β and matrix metalloproteinases in joints of arthritic mice (paper in progress).</p></span><span id="sec0085" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Concluding remarks</span><p id="par0130" class="elsevierStylePara elsevierViewall">MLIF was able to distinguish between healthy subjects and patients with RA, based perhaps upon a differential cell-activation degree and the signaling pathways in use. It is plausible to think that synovial cells would be a more representative entity for testing the interesting effects described in this work, and further studies are required to resolve this matter. The MLIF effect on caspase-1, translation, storage and release of mature IL-1β is unknown.</p><p id="par0135" class="elsevierStylePara elsevierViewall">The results presented in this work provide evidence of MLIF's most exquisite anti-inflammatory properties on prime and arthritic cells and encourage its research in other inflammatory processes.</p></span><span id="sec0100" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Ethical disclosures</span><p id="par0155" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleBold">Protection of human and animal subjects</span>. The authors declare that no experiments were performed on humans or animals for this investigation.</p><p id="par0160" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleBold">Confidentiality of Data</span>. The authors declare that no patient data appears in this article.</p><p id="par0165" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleBold">Right to privacy and informed consent</span>. The authors have obtained the informed consent of the patients and /or subjects mentioned in the article. The author for correspondence is in possession of this document.</p></span><span id="sec0090" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Funding</span><p id="par0140" class="elsevierStylePara elsevierViewall">This work was supported by <span class="elsevierStyleGrantSponsor" id="gs0005">Fondo de Investigación en Salud of IMSS, Mexico</span>, grant <span class="elsevierStyleGrantNumber" refid="gs0005">FIS/IMSS/PROT/356</span>.</p></span><span id="sec0095" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle">Conflicts of interest</span><p id="par0145" class="elsevierStylePara elsevierViewall">The authors have no conflicts of interest to declare.</p></span></span>" "textoCompletoSecciones" => array:1 [ "secciones" => array:14 [ 0 => array:2 [ "identificador" => "xres127041" "titulo" => array:5 [ 0 => "Abstract" 1 => "Objectives" 2 => "Material and methods" 3 => "Results" 4 => "Conclusions" ] ] 1 => array:2 [ "identificador" => "xpalclavsec114359" "titulo" => "Keywords" ] 2 => array:2 [ "identificador" => "xres127040" "titulo" => array:5 [ 0 => "Resumen" 1 => "Objetivo" 2 => "Material y Métodos" 3 => "Resultados" 4 => "Conclusiones" ] ] 3 => array:2 [ "identificador" => "xpalclavsec114358" "titulo" => "Palabras clave" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Introduction" ] 5 => array:3 [ "identificador" => "sec0010" "titulo" => "Materials and methods" "secciones" => array:8 [ 0 => array:2 [ "identificador" => "sec0015" "titulo" => "Cells" ] 1 => array:2 [ "identificador" => "sec0020" "titulo" => "Cultures" ] 2 => array:2 [ "identificador" => "sec0025" "titulo" => "Chemical substances" ] 3 => array:2 [ "identificador" => "sec0030" "titulo" => "Subjects" ] 4 => array:2 [ "identificador" => "sec0035" "titulo" => "RNA extraction and reverse transcription" ] 5 => array:2 [ "identificador" => "sec0040" "titulo" => "Real-time polymerase chain reaction analysis" ] 6 => array:2 [ "identificador" => "sec0045" "titulo" => "Enzyme-linked immunoabsorbent assays" ] 7 => array:2 [ "identificador" => "sec0050" "titulo" => "Statistical analysis" ] ] ] 6 => array:3 [ "identificador" => "sec0055" "titulo" => "Results" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "sec0060" "titulo" => "Cellular response to lipopolysaccharide and the antagonist effect of monocyte locomotion inhibitory factor" ] 1 => array:2 [ "identificador" => "sec0065" "titulo" => "Immunoreactivity of lipopolysaccharide-induced interleukin-1β" ] 2 => array:2 [ "identificador" => "sec0070" "titulo" => "Monocyte locomotion inhibitory factor effect on immunocompetent cells" ] 3 => array:2 [ "identificador" => "sec0075" "titulo" => "Inmunoreactivity of interleukin-1β in peripheral blood mononuclear cells" ] ] ] 7 => array:2 [ "identificador" => "sec0080" "titulo" => "Discussion" ] 8 => array:2 [ "identificador" => "sec0085" "titulo" => "Concluding remarks" ] 9 => array:2 [ "identificador" => "sec0100" "titulo" => "Ethical disclosures" ] 10 => array:2 [ "identificador" => "sec0090" "titulo" => "Funding" ] 11 => array:2 [ "identificador" => "sec0095" "titulo" => "Conflicts of interest" ] 12 => array:2 [ "identificador" => "xack38260" "titulo" => "Acknowledgments" ] 13 => array:1 [ "titulo" => "References" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2011-10-11" "fechaAceptado" => "2012-03-28" "PalabrasClave" => array:2 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec114359" "palabras" => array:4 [ 0 => "Amebic peptide" 1 => "Rheumatoid arthritis" 2 => "Inflammation" 3 => "Interleukin-1β" ] ] ] "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras clave" "identificador" => "xpalclavsec114358" "palabras" => array:4 [ 0 => "Artritis reumatoide" 1 => "Inflamación" 2 => "IL-1β" 3 => "Péptido amibiano" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "en" => array:2 [ "titulo" => "Abstract" "resumen" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">The monocyte locomotion inhibitory factor (MLIF) is a heat-stable pentapeptide produced by <span class="elsevierStyleItalic">Entamoeba histolytica</span> in culture. This factor displays several anti-inflammatory properties (<span class="elsevierStyleItalic">i.e.</span>, inhibition of locomotion and respiratory burst in monocytes, reduction of skin hypersensitivity and delay of mononuclear cells in human Rebuck skin windows) with inhibition of adhesion molecules, chemokines, and other genes including interleukin-1β (IL-1β). In animal models, it reduces carragenin-induced inflammation and delays the inflammatory process in murine collagen-induced arthritis (CIA).</p> <span class="elsevierStyleSectionTitle">Objectives</span><p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">To test, <span class="elsevierStyleItalic">in vitro</span>, the anti-inflammatory capacity of MLIF on a promonocytic human cell line (U-937) cells and peripheral blood mononuclear cells (PBMC) from healthy subjects and from patients with rheumatoid arthritis (RA).</p> <span class="elsevierStyleSectionTitle">Material and methods</span><p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">IL-1β gene expression was evaluated in cell cultures either in the presence of MLIF, lipopolysaccharide (LPS), or both. Relative gene expression and immunoreactivity of IL-1β were assayed in cells and supernatants, respectively.</p> <span class="elsevierStyleSectionTitle">Results</span><p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">Amebic peptide was able to down-regulate LPS-induced expression of IL-1β, in U-937 cells without a detectable effect upon the bioavailability of the cytokine. In similar culture conditions, MLIF was capable to down-regulate baseline and LPS-induced expression of IL-β only in PBMC from patients with RA. Peptide effect on immunoreactivity of IL-1β was not statistically significant.</p> <span class="elsevierStyleSectionTitle">Conclusions</span><p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">MLIF exerts, in primed cells, exquisite anti-inflammatory properties that deserve to be explored mechanistically.</p>" ] "es" => array:2 [ "titulo" => "Resumen" "resumen" => "<p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">El factor inhibidor de la locomoción de monocitos (FILM) es un pentapéptido termoestable producido por <span class="elsevierStyleItalic">Entamoeba histolytica</span> en cultivo. Este factor presenta diversas propiedades antiinflamatorias, a saber: inhibición de la locomoción y estallido respiratorio en monocitos, abatimiento de la hipersensibilidad por contacto al dinitroclorobenceno y retraso de la quimitoaxis de células mononucleares, disminución en la expresión de moléculas de adhesión y quimiocinas entre otros genes. En ratones el FILM reduce la inflamación inducida por carragenina y retrasa el proceso inflamatorio de la artritis inducida por colágena.</p> <span class="elsevierStyleSectionTitle">Objetivo</span><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">Evaluar <span class="elsevierStyleItalic">in vitro</span> el efecto del FILM sobre la expresión de IL-1β en la línea celular promonocítica humana (U-937) y en células mononucleares de sangre periférica provenientes de donadores sanos y de pacientes con artritis reumatoide.</p> <span class="elsevierStyleSectionTitle">Material y Métodos</span><p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">Se realizaron cultivos celulares en presencia de FILM, lipopolisacárido o ambos. Después del cultivo se determinó expresión relativa e inmunoreactividad de IL-1β en los botones celulares y sobrenadantes respectivamente.</p> <span class="elsevierStyleSectionTitle">Resultados</span><p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">El péptido amibiano pudo reducir la expresión de IL-1β inducida por LPS en células U937, sin mostrar un efecto detectable sobre la biodisponibilidad de la citocina. En condiciones de cultivo similares, el FILM fue capaz de disminuir la expresión de IL-1β, basal e inducida por LPS, sólo en células mononucleares provenientes de pacientes con artritis. Su efecto sobre la inmunoreactividad de la citocina no fue significativo estadísticamente.</p> <span class="elsevierStyleSectionTitle">Conclusiones</span><p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">El FILM ejerce en las células activadas propiedades antiinflamatorias exquisitas que merecen ser exploradas mecanísticamente.</p>" ] ] "multimedia" => array:5 [ 0 => array:7 [ "identificador" => "fig0005" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1111 "Ancho" => 1689 "Tamanyo" => 101920 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Time-course expression of IL-1β in U-937 cells. Triplicate cultures of 4<span class="elsevierStyleHsp" style=""></span>×<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleSup">6</span> U-937 cells in the presence of MLIF, LPS or both were harvested at 0.3, 1, 2, 4, 6, 8 and 10<span class="elsevierStyleHsp" style=""></span>h. RNA was obtained from pellets and used for real time PCR. Comparative expression was established using unstimulated cells as reference. LPS induced a strong up-regulation of IL-1β which peaks at 4<span class="elsevierStyleHsp" style=""></span>h. MLIF <span class="elsevierStyleItalic">per se</span> did not affect IL-1β basal expression but MLIF was able to reduce significantly the stimulatory effect of LPS when amebic peptide was added simultaneously to LPS (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.05). Bars of SEM are <1 in all points.</p>" ] ] 1 => array:7 [ "identificador" => "fig0010" "etiqueta" => "Figure 2" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr2.jpeg" "Alto" => 932 "Ancho" => 1513 "Tamanyo" => 56972 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">Time-course of IL-1β immunoreactivity in U-937 cells. Triplicate cultures of 4<span class="elsevierStyleHsp" style=""></span>×<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleSup">6</span> U-937 cells in the presence of MLIF, LPS or both were harvested at 4, 6 and 8<span class="elsevierStyleHsp" style=""></span>h by centrifugation. Supernatant fluids were employed for IL-1β immunoreactivity. In general IL-1β released to medium was low at 4 and 8<span class="elsevierStyleHsp" style=""></span>h, response to LPS was higher at 6<span class="elsevierStyleHsp" style=""></span>h *(<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.05), MLIF <span class="elsevierStyleItalic">per se</span> had no effect over IL-1β release and did not interfere with LPS stimulation.</p>" ] ] 2 => array:7 [ "identificador" => "fig0015" "etiqueta" => "Figure 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 1620 "Ancho" => 2222 "Tamanyo" => 148002 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">Effect of MLIF in PBMC from healthy and patients with RA. Healthy donors (<span class="elsevierStyleItalic">n</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>13) and patients with RA (<span class="elsevierStyleItalic">n</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>11) PBMC were cultured during 4<span class="elsevierStyleHsp" style=""></span>h in the presence of LPS, MLIF or both. qPCR analysis for IL-1β transcripts was carried out in each case and comparison between groups established by a normalized expression ratio (ner). (a) Patients with AR constitutively express more IL-1β than healthy donors. IL-1β ner between them was statistically different (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.03). (b) MLIF shows a down-regulatory effect on IL-1β expression in patients with RA which ner is <1 in 91% of cases (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.01). (c) Capacity of LPS to up-regulate IL-1β in both healthy donors and patients with RA was not significantly different. (d) MLIF was able to down-regulate LPS-induction in all patients with RA (<span class="elsevierStyleItalic">p</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>0.001).</p>" ] ] 3 => array:7 [ "identificador" => "fig0020" "etiqueta" => "Figure 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 813 "Ancho" => 1483 "Tamanyo" => 50423 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0070" class="elsevierStyleSimplePara elsevierViewall">Immunoreactivity of IL-1β in PBMC from healthy donors and patients with RA IL-1β immunoreactivity was detected by ELISA in supernatant fluids of 6<span class="elsevierStyleHsp" style=""></span>h cultures of PBMC from healthy donors (<span class="elsevierStyleItalic">n</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>11) and patients with RA (<span class="elsevierStyleItalic">n</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>13). IL-1β was not detected in most patients with RA and healthy donors. Patients with RA show higher spontaneous release of IL-1β than healthy donors, and a poor response to LPS stimulus. MLIF <span class="elsevierStyleItalic">per se</span> seems to down-regulate IL-1β in patients with RA, and interferes with LPS induction in both healthy donors and patients with RA. Statistics were not available because of the low number of immunoreactive samples.</p>" ] ] 4 => array:5 [ "identificador" => "eq0005" "tipo" => "MULTIMEDIAFORMULA" "mostrarFloat" => false "mostrarDisplay" => true "Formula" => array:5 [ "Matematica" => "ner=fg IL-1βfg GAPDH" "Fichero" => "si1.jpeg" "Tamanyo" => 1846 "Alto" => 38 "Ancho" => 119 ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0005" "bibliografiaReferencia" => array:16 [ 0 => array:3 [ "identificador" => "bib0005" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Inhibition of human monocyte locomotion by products of axenically grown <span class="elsevierStyleItalic">E. histolytica</span>" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => array:6 [ 0 => "R. Kretschmer" 1 => "M.L. Collado" 2 => "M.G. Pacheco" 3 => "M.C. Salinas" 4 => "M. Lopez-Osuna" 5 => "M. 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The style review of the manuscript by Ms Maggie Brunner is greatly appreciated.</p>" ] ] ] "idiomaDefecto" => "en" "url" => "/1699258X/0000000800000006/v1_201305061930/S1699258X12001362/v1_201305061930/en/main.assets" "Apartado" => array:4 [ "identificador" => "17499" "tipo" => "SECCION" "es" => array:2 [ "titulo" => "Originales" "idiomaDefecto" => true ] "idiomaDefecto" => "es" ] "PDF" => "https://static.elsevier.es/multimedia/1699258X/0000000800000006/v1_201305061930/S1699258X12001362/v1_201305061930/en/main.pdf?idApp=UINPBA00004M&text.app=https://reumatologiaclinica.org/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1699258X12001362?idApp=UINPBA00004M" ]
| año/Mes | Html | Total | |
|---|---|---|---|
| 2024 Noviembre | 7 | 18 | 25 |
| 2024 Octubre | 29 | 26 | 55 |
| 2024 Septiembre | 20 | 11 | 31 |
| 2024 Agosto | 40 | 23 | 63 |
| 2024 Julio | 33 | 29 | 62 |
| 2024 Junio | 38 | 22 | 60 |
| 2024 Mayo | 31 | 18 | 49 |
| 2024 Abril | 34 | 12 | 46 |
| 2024 Marzo | 44 | 31 | 75 |
| 2024 Febrero | 32 | 16 | 48 |
| 2024 Enero | 47 | 21 | 68 |
| 2023 Diciembre | 29 | 29 | 58 |
| 2023 Noviembre | 28 | 26 | 54 |
| 2023 Octubre | 27 | 33 | 60 |
| 2023 Septiembre | 90 | 40 | 130 |
| 2023 Agosto | 32 | 12 | 44 |
| 2023 Julio | 36 | 26 | 62 |
| 2023 Junio | 36 | 18 | 54 |
| 2023 Mayo | 30 | 30 | 60 |
| 2023 Abril | 23 | 10 | 33 |
| 2023 Marzo | 45 | 26 | 71 |
| 2023 Febrero | 39 | 24 | 63 |
| 2023 Enero | 32 | 26 | 58 |
| 2022 Diciembre | 53 | 43 | 96 |
| 2022 Noviembre | 57 | 45 | 102 |
| 2022 Octubre | 71 | 37 | 108 |
| 2022 Septiembre | 90 | 30 | 120 |
| 2022 Agosto | 78 | 61 | 139 |
| 2022 Julio | 73 | 68 | 141 |
| 2022 Junio | 91 | 31 | 122 |
| 2022 Mayo | 110 | 43 | 153 |
| 2022 Abril | 112 | 57 | 169 |
| 2022 Marzo | 78 | 59 | 137 |
| 2022 Febrero | 44 | 32 | 76 |
| 2022 Enero | 41 | 45 | 86 |
| 2021 Diciembre | 63 | 35 | 98 |
| 2021 Noviembre | 61 | 42 | 103 |
| 2021 Octubre | 43 | 50 | 93 |
| 2021 Septiembre | 34 | 45 | 79 |
| 2021 Agosto | 39 | 38 | 77 |
| 2021 Julio | 30 | 28 | 58 |
| 2021 Junio | 29 | 36 | 65 |
| 2021 Mayo | 37 | 51 | 88 |
| 2021 Abril | 78 | 105 | 183 |
| 2021 Marzo | 46 | 33 | 79 |
| 2021 Febrero | 38 | 22 | 60 |
| 2021 Enero | 30 | 24 | 54 |
| 2020 Diciembre | 26 | 15 | 41 |
| 2020 Noviembre | 40 | 19 | 59 |
| 2020 Octubre | 29 | 15 | 44 |
| 2020 Septiembre | 61 | 21 | 82 |
| 2020 Agosto | 82 | 17 | 99 |
| 2020 Julio | 95 | 20 | 115 |
| 2020 Junio | 31 | 28 | 59 |
| 2020 Mayo | 42 | 35 | 77 |
| 2020 Abril | 28 | 26 | 54 |
| 2020 Marzo | 22 | 29 | 51 |
| 2020 Febrero | 63 | 32 | 95 |
| 2020 Enero | 35 | 32 | 67 |
| 2019 Diciembre | 48 | 24 | 72 |
| 2019 Noviembre | 26 | 21 | 47 |
| 2019 Octubre | 50 | 17 | 67 |
| 2019 Septiembre | 45 | 30 | 75 |
| 2019 Agosto | 30 | 19 | 49 |
| 2019 Julio | 22 | 22 | 44 |
| 2019 Junio | 28 | 44 | 72 |
| 2019 Mayo | 41 | 143 | 184 |
| 2019 Abril | 38 | 38 | 76 |
| 2019 Marzo | 33 | 22 | 55 |
| 2019 Febrero | 32 | 8 | 40 |
| 2019 Enero | 25 | 30 | 55 |
| 2018 Diciembre | 84 | 56 | 140 |
| 2018 Noviembre | 123 | 12 | 135 |
| 2018 Octubre | 109 | 8 | 117 |
| 2018 Septiembre | 40 | 12 | 52 |
| 2018 Agosto | 33 | 8 | 41 |
| 2018 Julio | 26 | 5 | 31 |
| 2018 Mayo | 2 | 1 | 3 |
| 2018 Abril | 41 | 7 | 48 |
| 2018 Marzo | 98 | 7 | 105 |
| 2018 Febrero | 26 | 2 | 28 |
| 2018 Enero | 28 | 2 | 30 |
| 2017 Diciembre | 34 | 6 | 40 |
| 2017 Noviembre | 36 | 9 | 45 |
| 2017 Octubre | 28 | 4 | 32 |
| 2017 Septiembre | 26 | 12 | 38 |
| 2017 Agosto | 27 | 10 | 37 |
| 2017 Julio | 22 | 8 | 30 |
| 2017 Junio | 42 | 5 | 47 |
| 2017 Mayo | 61 | 7 | 68 |
| 2017 Abril | 35 | 56 | 91 |
| 2017 Marzo | 32 | 37 | 69 |
| 2017 Febrero | 19 | 3 | 22 |
| 2017 Enero | 26 | 8 | 34 |
| 2016 Diciembre | 64 | 16 | 80 |
| 2016 Noviembre | 50 | 14 | 64 |
| 2016 Octubre | 66 | 22 | 88 |
| 2016 Septiembre | 55 | 18 | 73 |
| 2016 Agosto | 22 | 8 | 30 |
| 2016 Julio | 10 | 6 | 16 |
| 2016 Febrero | 3 | 0 | 3 |
| 2016 Enero | 6 | 15 | 21 |
| 2015 Diciembre | 5 | 0 | 5 |
| 2015 Octubre | 1 | 0 | 1 |
| 2015 Septiembre | 1 | 0 | 1 |
| 2015 Agosto | 2 | 0 | 2 |
| 2015 Julio | 18 | 6 | 24 |
| 2015 Junio | 22 | 8 | 30 |
| 2015 Mayo | 57 | 28 | 85 |
| 2015 Abril | 24 | 12 | 36 |
| 2015 Marzo | 31 | 13 | 44 |
| 2015 Febrero | 25 | 0 | 25 |
| 2015 Enero | 42 | 0 | 42 |
| 2014 Diciembre | 35 | 0 | 35 |
| 2014 Noviembre | 40 | 0 | 40 |
| 2014 Octubre | 31 | 0 | 31 |
| 2014 Septiembre | 40 | 0 | 40 |
| 2014 Agosto | 43 | 0 | 43 |
| 2014 Julio | 50 | 0 | 50 |
| 2014 Junio | 63 | 0 | 63 |
| 2014 Mayo | 99 | 0 | 99 |
| 2014 Abril | 50 | 0 | 50 |
| 2014 Marzo | 56 | 12 | 68 |
| 2014 Febrero | 44 | 18 | 62 |
| 2014 Enero | 33 | 9 | 42 |
| 2013 Diciembre | 38 | 9 | 47 |
| 2013 Noviembre | 41 | 6 | 47 |
| 2013 Octubre | 57 | 8 | 65 |
| 2013 Septiembre | 57 | 9 | 66 |
| 2013 Agosto | 37 | 14 | 51 |
| 2013 Julio | 68 | 10 | 78 |
| 2013 Junio | 39 | 9 | 48 |
| 2013 Mayo | 33 | 13 | 46 |
| 2013 Abril | 55 | 16 | 71 |
| 2013 Marzo | 40 | 22 | 62 |
| 2013 Febrero | 66 | 17 | 83 |
| 2013 Enero | 111 | 60 | 171 |
| 2012 Diciembre | 107 | 79 | 186 |
| 2012 Noviembre | 67 | 55 | 122 |
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