OBJECTIVETo construct a eukaryotic expression plasmid containing human triggering receptor expressed on myeloid cells-1(TREM-1) gene.

METHODSThe entire gene coding region of human TREM-1 was amplified from total RNA of human peripheral blood by means of RT-PCR. The fragment of TREM-1 was cloned to vector pUCm-T. After digestion by restriction endonuclease BamH I and Pst I, the fragment was subcloned into the eukaryotic expressing vector pEGFP-C3. This recombinant vector was transfected into 293 cells using liposome. The expression level of TREM-1 was determined by fluorescence microscope and Western blot assay. The recombinant TREM-1 vector was transfected into THP-1 cells. After stimulation with 100 ng/ml LPS for 24 h, the mRNA levels of TNF-α and IL-1β were measured using RT-PCR.

RESULTThe expression vector was constructed, and the result of the DNA sequencing showed that the constructed plasmid containing the TREM-1 gene. Fluorescence microscope and Western blot analysis showed that TREM-1 protein was expressed in 293 cells successfully. After transfection into THP-1 cells, recombinant TREM-1 could upregulate the mRNA levels of TNF-α and IL-1β.

CONCLUSIONEukaryotic expression plasmid pEGFP-TREM-1 is successfully constructed and showed biological activity.

Cells, Cultured ; Genetic Vectors ; Humans ; Membrane Glycoproteins ; genetics ; Plasmids ; genetics ; Receptors, Immunologic ; genetics ; Transfection ; Triggering Receptor Expressed on Myeloid Cells-1

OBJECTIVE: To study the significance of the level of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in serum and bronchoalveolar lavage fluid (BALF), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and Sequential Organ Failure Assessment (SOFA) score in evaluating the conditions and prognosis of children with severe pneumonia. METHODS: A total of 76 children with severe pneumonia who were admitted from August 2017 to October 2019 were enrolled as the severe pneumonia group. According to the treatment outcome, they were divided into a non-response group with 34 children and a response group with 42 children. Ninety-four children with common pneumonia who were admitted during the same period of time were enrolled as the common pneumonia group. One hundred healthy children who underwent physical examination in the outpatient service during the same period of time were enrolled as the control group. The serum level of sTREM-1, APACHE II score, and SOFA score were measured for each group, and the level of sTREM-1 in BALF was measured for children with severe pneumonia. The correlation of the above indices with the severity and prognosis of severe pneumonia in children was analyzed. RESULTS: The severe pneumonia group had significantly higher serum sTREM-1 level, APACHEII score, and SOFA score than the common pneumonia group and the control group (P<0.05). For the children with severe pneumonia, the non-response group had significant increases in the levels of sTREM-1 in serum and BALF and SOFA score on day 7 after admission, while the response group had significant reductions in these indices, and there were significant differences between the two groups (P<0.05). Positive correlation was found between any two of serum sTREM-1, BALF sTREM-1, and SOFA score (P<0.05). APACHE II score was not correlated with serum sTREM-1, BALF sTREM-1, and SOFA score (P>0.05). CONCLUSIONS The level of sTREM-1 in serum and BALF and SOFA score can be used to evaluate the severity and prognosis of severe pneumonia in children.
APACHE ; Bronchoalveolar Lavage Fluid ; Child ; Humans ; Organ Dysfunction Scores ; Pneumonia ; Prognosis ; ROC Curve ; Sepsis ; Triggering Receptor Expressed on Myeloid Cells-1

OBJECTIVE: Soluble triggering receptors expressed by myeloid cells-1 (sTREM-1) and inflammatory cytokine tumor necrosis factor-α (TNF-α) in macrophage cells were stimulated by Porphyromonas gingivalis-lipopolysaccharide (Pg-LPS) to investigate the expression of triggering receptors expressed by myeloid cells-1 (TREM-1) and further explore the correlation between TREM-1 and the pathogenesis of periodontitis. METHODS: THP-1 cells (a human monocytic cell line derived from an acute monocytic leukemia patient) were induced to differentiate THP-1 macrophages by phorbol-12-myristate-13-acetate and were injected with 0 (blank control), 0.5, or 1.0 μg·mL⁻¹ Pg-LPS. The THP-1 cells were then grouped in accordance with incubation time, and each group was incubated for 4, 6, 12, or 24 h. The expression of the TREM-1 mRNA in macrophages was detected by real-time quantitative polymerase chain reaction, while the expression of TREM-1 protein was detected by Western blot; the site where TREM-1 protein expression was observed in macrophages was detected by immunofluorescence staining, and the expression of soluble sTREM-1 and TNF-α in cell culture medium was detected by enzyme-linked immunosorbent assay. RESULTS: Compared with the blank control group, the expression of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in Pg-LPS-stimulated macrophages was significantly upregulated (P<0.05). The expression of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in the supernatant of cell culture was higher in the 1.0 μg·mL⁻¹ Pg-LPS group than in the 0.5 μg·mL⁻¹ group; this expression was statistically significant since the 6, 4, and 4 h time point (P<0.05). Cell immunofluorescence staining showed that TREM-1 protein was positive when the THP-1 macrophages was stimulated by Pg-LPS (1.0 μg·mL⁻¹) for 24 h, and the staining sites of TREM-1 were mainly located in the cell membrane of the macrophages (P<0.05). The expression level of TNF-α increased in groups stimulated by Pg-LPS, and the expression level of TNF-α was significantly higher in 1.0 μg·mL⁻¹ Pg-LPS stimulated groups than in 0.5 μg·mL⁻¹ Pg-LPS-stimulated groups since the 6 h time point (P<0.05). The expressions of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in 0.5 μg·mL⁻¹ Pg-LPS-stimulated macrophages were positively correlated with one another (r=1, P<0.05), but no statistically significant correlation was found in the expression of TNF-α. The positive correlation between sTREM-1 and TNF-α expressions was detected when macrophages were stimulated by 1.0 μg·mL⁻¹ Pg-LPS (r=1, P<0.05). CONCLUSIONS The expression of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in the culture supernatant in Pg-LPS-stimulated macrophages was significantly upregulated on the basis of the concentration of Pg-LPS; moreover, their upregulation was positively correlated with one another. The expression of TNF-α in the supernatant of cell culture was also upregulated and was positively correlated with the expression of sTREM-1 at the group of high Pg-LPS concentration (1.0 μg·mL⁻¹). Results reveal that TREM-1, which has been realized as a proinflammatory receptor protein, can promote the development of periodontitis by regulating the expression of TNF-α in macrophages.
Adult ; Humans ; Lipopolysaccharides ; Macrophages ; metabolism ; Myeloid Cells ; Periodontitis ; metabolism ; microbiology ; Porphyromonas gingivalis ; pathogenicity ; Triggering Receptor Expressed on Myeloid Cells-1 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo determine the diagnostic values of plasma CD64 and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in children with pneumonia.

METHODSSixty children with pneumonia between August 2014 and October 2015 were classified into bacterial pneumonia group (25 cases), viral pneumonia group (17 cases), and Mycoplasma pneumonia group (18 cases) according to their clinical manifestations, pathogen cultures, and X-ray findings. Another 30 healthy children who underwent physical examination during the same period were selected as the control group. The concentrations of CD64 and sTREM-1 in blood samples were determined using ELISA. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic sensitivity and specificity of plasma CD64 and/or sTREM-1 for bacterial pneumonia.

RESULTSThe expression of CD64 and sTREM-1 in the bacterial pneumonia group was significantly higher than that in the viral pneumonia, Mycoplasma pneumonia, and control groups (P<0.05). The areas under the ROC curves of CD64, sTREM-1, and a combination of the two markers for diagnosing bacterial pneumonia were 0.878, 0.805, and 0.956, respectively. The sensitivity and specificity of CD64 for diagnosing bacterial pneumonia were 81.30% and 92.32%, respectively, when the cut-off value was 641 pg/mL. The sensitivity and specificity of sTREM-1 for diagnosing bacterial pneumonia were 78.65% and 84.67%, respectively, when the cut-off value was 1 479 pg/mL. The sensitivity and specificity of a combination of the two markers for diagnosing bacterial pneumonia were 93.15% and 91.54%, respectively.

CONCLUSIONSPlasma CD64 and sTREM-1 can be used as markers for diagnosing pediatric bacterial pneumonia, and a combination of the two markers results in better diagnosis.

Biomarkers ; blood ; Child ; Female ; Humans ; Male ; Membrane Glycoproteins ; blood ; Pneumonia ; blood ; diagnosis ; ROC Curve ; Receptors, IgG ; blood ; Receptors, Immunologic ; blood ; Triggering Receptor Expressed on Myeloid Cells-1

OBJECTIVE: To study the value of serum procalcitonin (PCT) combined with soluble triggering receptor expressed on myeloid cells-1 (STREM-1) in the differential diagnosis of bacterial diarrhea and viral diarrhea in children. METHODS: A retrospective analysis was performed on the medical data of 73 children with bacterial infectious diarrhea (bacteria group) and 68 children with viral infectious diarrhea (virus group) who were treated from February 2018 to May 2019. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic efficacy of serum PCT and STREM-1 for bacterial infectious diarrhea and viral infectious diarrhea. RESULTS: Compared with the virus group, the bacteria group had significantly higher detection rates of fecal red blood cells (79% vs 43%, P<0.05) and pus (51% vs 19%, P<0.05), as well as significantly higher serum levels of PCT and STREM-1 (P<0.05). The ROC curve analysis showed that in the differential diagnosis of bacterial infectious diarrhea and viral infectious diarrhea, serum PCT had a cut-off value of 0.97 ng/mL and an area under the ROC curve (AUC) of 0.792, and STREM-1 had a cut-off value of 15.66 ng/mL and an AUC of 0.889. Serum PCT combined with STREM-1 had an AUC of 0.955, which was significantly higher than that of each index alone (P<0.05). CONCLUSIONS Children with bacterial diarrhea have increased serum levels of PCT and STREM-1 than those with viral diarrhea. Both serum PCT and STREM-1 can be used as the indices for the differential diagnosis of bacterial diarrhea and viral diarrhea in children, and the combined measurement of PCT and STREM-1 can improve the efficiency of differential diagnosis.
Bacteria ; Biomarkers ; C-Reactive Protein ; Child ; Diagnosis, Differential ; Diarrhea ; Humans ; Procalcitonin ; blood ; Prospective Studies ; Retrospective Studies ; Triggering Receptor Expressed on Myeloid Cells-1 ; blood

OBJECTIVETo investigate the expression of triggering receptor expressed on myeloid cells (TREM-1) in monocytes of burn patients at early post-burn stage, and its significance.

METHODSThe monocytes of 8 healthy volunteers (A group), 29 patients with mild and moderate burn (B group), and 9 patients with severe and very serious burns (C group) were isolated from the blood, and the THEM-1 mRNA and protein expression were determined by semi-quantitative RT-PCR and flow cytometry, respectively. The plasma levels of TNF-alpha, IL-1beta were determined by ELISA method.

RESULTSThe value of TREM-1 mRNA expression in A, B and C groups were 0.74 +/- 0.13, 1.24 +/- 0.09, and 1.46 +/-0.07, respectively, and the expression rates on cell surface in the 3 groups were (9 +/- 4)%, (51 +/- 6)%, and (71 +/- 7)%, respectively, and there were significant differences among the three groups (P = 0.000). the plasma levels of TNF-alpha and IL-1beta in B and C groups were obviously higher than that in A group (P = 0.000), and they were positively correlated to TREM-1 expression (rs = 0.68, 0.72, P = 0.000).

CONCLUSIONIncreased expression of TREM-1 in monocytes of burn patients at early post-burn stage is correlated with the release of inflammatory factors, indicating that TREM-1 might contribute to the onset and development of acute inflammatory response after burns.

Adult ; Burns ; blood ; Female ; Humans ; Interleukin-1 ; blood ; Male ; Membrane Glycoproteins ; metabolism ; Middle Aged ; Monocytes ; metabolism ; Myeloid Cells ; RNA, Messenger ; metabolism ; Receptors, Immunologic ; metabolism ; Triggering Receptor Expressed on Myeloid Cells-1 ; Tumor Necrosis Factor-alpha ; blood

OBJECTIVETo investigate the expression profile of human soluble triggering receptor on myeloid cell-1 (sTREM-1) in patients with multiple trauma and determine its clinical significance.

METHODSPeripheral blood of 52 patients admitted to the hospital from October 2007 to January 2008 with multiple traumas with injury severity score (ISS) > or = 16 and 7 healthy volunteers were obtained, and sera samples were isolated. sTREM-1 was determined by semi-quantitative immunoblot technique. TNF-alpha and C-reactive protein (CRP) were determined by ELISA.

RESULTSsTREM-1 of patients with multiple traumas was significantly increased as compared with that of control (P < 0.001), and sTREM-1 of ISS > or = 25 group was significantly higher than that of 16 < or = ISS < 25 group (P < 0.05). sTREM-1 level correlated closely with TNF-alpha level (r = 0.845, P < 0.05), but did not correlate with CRP (r = 0.426, P > 0.05). In patients with sepsis, sTREM-1 on 1, 2 and 7 d was (25.1 +/- 2.2), (31.9 +/- 2.6) and (25.2 +/- 1.9) ng/L, respectively. In patients without sepsis, sTREM-1 on 1, 2 and 7 d was (15.8 +/- 1.3), (24.2 +/- 2.0) and (13.9 +/- 1.5) ng/L, respectively. sTREM-1 of patients with sepsis was significantly higher than that of patients without sepsis (P < 0.05).

CONCLUSIONSSerum sTREM-1 correlates closely with ISS, TNF-alpha and onset of sepsis, indicating that it may play an important role in the development of sepsis in patients with multiple traumas.

Adolescent ; Adult ; C-Reactive Protein ; metabolism ; Female ; Humans ; Male ; Membrane Glycoproteins ; blood ; Middle Aged ; Multiple Trauma ; blood ; complications ; immunology ; Myeloid Cells ; metabolism ; Receptors, Immunologic ; blood ; Sepsis ; etiology ; Triggering Receptor Expressed on Myeloid Cells-1 ; Tumor Necrosis Factor-alpha ; blood ; Young Adult

OBJECTIVETo investigate the role of triggering receptors expressed on myeloid-1(TREM-1) in innate response to Porphyromonas gingivalis(Pg) in mice macrophages and its potential role in periodontitis development.

METHODSPeritoneal macrophages from mice were harvested, separated and cultured, then challenged with viable Pg. Transcription and protein expression in macrophages were assessed with real time PCR and flow cytometry respectively.LP-17 peptide (10, 100 and 1000 µg/L) was utilized to block TREM-1, and tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were detected by enzyme linked absorbent analysis.

RESULTSAt 2 h after Pg challenge, transcription of TREM-1 was significantly up-regulated after Pg challenge[(7.99 ± 1.11) fold vs blank]. At 24 h after bacteria infection, increased TREM-1 expression was demonstrated by flow cytometry, with mean fluorescent intensity increasing from (7.05 ± 1.85) in blank group to (13.17 ± 2.33) in experimental group. Proinflammatory cytokine (TNF-α and IL-6) production was significantly decreased after blocking TREM-1 by LP-17 peptide(100 and 1000 µg/L).

CONCLUSIONSTREM-1 enhanced innate immune response to Pg in macrophages, which may facilitate periodontitis development.

Animals ; Cells, Cultured ; Interleukin-6 ; metabolism ; Macrophages, Peritoneal ; cytology ; immunology ; metabolism ; Membrane Glycoproteins ; metabolism ; Mice ; Mice, Inbred C57BL ; Peptides ; pharmacology ; Porphyromonas gingivalis ; immunology ; Receptors, Immunologic ; metabolism ; Triggering Receptor Expressed on Myeloid Cells-1 ; Tumor Necrosis Factor-alpha ; metabolism ; Up-Regulation

BACKGROUNDTriggering receptors expressed on myeloid cells (TREM) proteins are a family of cell surface receptors expressed broadly by cells of the myeloid lineage. The aim of this study was to investigate the clinical significance of soluble TREM-1 (sTREM-1) in pleural effusions, and to determine the effects of pneumonia on pleural sTREM-1 concentrations.

METHODSPleural fluid was collected from 109 patients who presented to the respiratory institute (35 with malignant pleural effusion, 31 with tuberculous pleural effusion, 21 with bacterial pleural effusion, and 22 with transudate). The concentrations of sTREM-1, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were determined in effusion and serum samples by enzyme linked immunosorbent assay (ELISA).

RESULTSThe concentrations of sTREM-1 in bacterial pleural effusion were significantly higher than those in malignant, tuberculous, and transudative groups (all P < 0.001). An sTREM-1 cutoff value of 768.1 ng/L had a sensitivity of 86% and a specificity of 93%. Pleural sTREM-1 levels were positively correlated with levels of TNF-alpha and IL-1beta. Patients with complicating bacterial pneumonia did not have elevated concentration of sTREM-1 in pleural effusion when compared with patients without pneumonia.

CONCLUSIONSDetermination of pleural sTREM-1 may improve the ability of clinicians to differentiate pleural effusion patients of bacterial origin from those with other etiologies. The occurrence of bacterial pneumonia did not affect pleural sTREM-1 concentrations.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cross-Sectional Studies ; Humans ; Interleukin-1beta ; analysis ; Membrane Glycoproteins ; analysis ; Middle Aged ; Pleural Effusion ; diagnosis ; metabolism ; Pneumonia ; metabolism ; Prospective Studies ; Receptors, Immunologic ; analysis ; Triggering Receptor Expressed on Myeloid Cells-1 ; Tumor Necrosis Factor-alpha ; analysis

OBJECTIVETo study whether infantile wheezing pneumonia has similar immune mechanisms to asthma by determining the levels of serum inflammatory factors in wheezing infants with community-acquired pneumonia (CAP).

METHODSForty-two infants with CAP but without wheezing, 47 infants with CAP and wheezing, and 30 healthy infants as a control were recruited in the study. The peripheral blood levels of C-reactive protein, procalcitonin, soluble triggering receptor expressed on myeloid cell-l, interferon-γ, interleukin-4, interleukin-10, and periostin were compared in the three groups.

RESULTSThe serum levels of procalcitonin, soluble triggering receptor expressed on myeloid cell-l, interleukin-4 and interleukin-10 in the two CAP groups were higher than in the control group (P<0.05). The ratio of interferon-γ/interleukin-4 in the wheezing pneumonia group was lower than in the non-wheezing pneumonia and control groups (P<0.05). The serum level of periostin in the wheezing pneumonia group was higher than in the non-wheezing pneumonia and control groups (P<0.05).

CONCLUSIONSThe unbalanced ratio of interferon-γ/interleukin-4 and airway eosinophilic inflammation in wheezing infants with pneumonia suggest infantile pneumonia with wheezing may has similar immune mechanisms to asthma.

Child, Preschool ; Community-Acquired Infections ; immunology ; Female ; Humans ; Infant ; Interferon-gamma ; blood ; Interleukin-10 ; blood ; Interleukin-4 ; blood ; Male ; Membrane Glycoproteins ; blood ; Pneumonia ; immunology ; Receptors, Immunologic ; blood ; Respiratory Sounds ; immunology ; Triggering Receptor Expressed on Myeloid Cells-1