Regulation of CCL2 expression in human vascular endothelial cells by a neighboring divergently transcribed long noncoding RNA.

Atherosclerosis is a chronic inflammatory disease that is driven, in part, by activation of vascular endothelial cells (ECs). In response to inflammatory stimuli, the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway orchestrates the expression of a network of EC genes that contribute to monocyte recruitment and diapedesis across the endothelium. Although many long noncoding RNAs (lncRNAs) are dysregulated in atherosclerosis, they remain poorly characterized, especially in the context of human vascular inflammation. Prior studies have illustrated that lncRNAs can regulate their neighboring protein-coding genes via interaction with protein complexes. We therefore identified and characterized neighboring interleukin-1ß (IL-1ß)-regulated messenger RNA (mRNA)-lncRNA pairs in ECs. We found these pairs to be highly correlated in expression, especially when located within the same chromatin territory. Additionally, these pairs were predominantly divergently transcribed and shared common gene regulatory elements, characterized by active histone marks and NF-κB binding. Further analysis was performed on lncRNA-CCL2, which is transcribed divergently to the gene, CCL2, encoding a proatherosclerotic chemokine. LncRNA-CCL2 and CCL2 showed coordinate up-regulation in response to inflammatory stimuli, and their expression was correlated in unstable symptomatic human atherosclerotic plaques. Knock-down experiments revealed that lncRNA-CCL2 positively regulated CCL2 mRNA levels in multiple primary ECs and EC cell lines. This regulation appeared to involve the interaction of lncRNA-CCL2 with RNA binding proteins, including HNRNPU and IGF2BP2. Hence, our approach has uncovered a network of neighboring mRNA-lncRNA pairs in the setting of inflammation and identified the function of an lncRNA, lncRNA-CCL2, which may contribute to atherogenesis in humans.

Assessment of urinary kidney injury molecule-1 and interleukin-18 in the early post-burn period to predict acute kidney injury for various degrees of burn injury.

BACKGROUND: Burn patients with AKI have a higher mortality, rapid diagnosis and early treatment of AKI are necessary. Recent studies have demonstrated that urinary KIM-1 and IL-18 are potential biomarkers of early-stage AKI, however, changes in urinary KIM-1 and IL-18 levels are unclear in patients with burns. The aim of our study was to determine whether combined KIM-1 and IL-18 are more sensitive than traditional markers in detecting kidney injury in patients with burns. METHODS: Ninety-five burn patients hospitalized at the Burns and Plastic Surgery Center of our hospital from April 2013 to September 2013 were enrolled into this prospective study and divided into mild- (n = 37), moderate- (n = 30) and severe-burn groups (n = 28) by burn injury surface area. In the moderate- and severe-burn groups, patients were subcategorized to either the acute kidney injury (AKI) group, in which serum creatinine (Scr) increased to ≥ 26.5 µmol/L within 48 h, or the non-AKI group. Fifteen healthy subjects were selected as a control group. Blood specimens were collected to determine blood urea nitrogen (BUN), Scr, and other biochemical indicators. Urine samples collected at admission and 48 h after admission were analyzed for KIM-1 and IL-18. Correlations among urinary KIM-1 and IL-18, burn degree, and clinical biochemical indicators were investigated. RESULTS: AKI occurred in 11.2 % of burn patients (none in the mild-burn group). AKI developed 48 h after admission in 10.0 % of the moderate- and 28.6 % of the severe-burn groups. Urinary KIM-1 concentration in the moderate- and severe-burn groups was significantly higher than that in the control group; urinary IL-18 concentrations did not differ significantly among the burn and control groups. The AKI group had significantly higher concentrations of urinary KIM-1 and IL-18 than the non-AKI group, both at admission (p = 0.001 and p < 0.001, respectively) and 48 h later (p = 0.001 and p < 0.001, respectively). Both urinary KIM-1 and IL-18 increased before Scr. Receiver operating-curve (ROC) analysis demonstrated that KIM-1 combined with IL-18 predicted AKI with 72.7 % sensitivity and 92.8 % specificity. The area under the ROC curve was 0.904. CONCLUSIONS: Our results suggest that urinary KIM-1 and IL-18 may be used as early, sensitive indicators of AKI in patients with burns of varying degrees and provide clinical clues that can be used in early prevention of AKI.

Differential Expression Enrichment Tool (DEET): an interactive atlas of human differential gene expression.

Differential gene expression analysis using RNA sequencing (RNA-seq) data is a standard approach for making biological discoveries. Ongoing large-scale efforts to process and normalize publicly available gene expression data enable rapid and systematic reanalysis. While several powerful tools systematically process RNA-seq data, enabling their reanalysis, few resources systematically recompute differentially expressed genes (DEGs) generated from individual studies. We developed a robust differential expression analysis pipeline to recompute 3162 human DEG lists from The Cancer Genome Atlas, Genotype-Tissue Expression Consortium, and 142 studies within the Sequence Read Archive. After measuring the accuracy of the recomputed DEG lists, we built the Differential Expression Enrichment Tool (DEET), which enables users to interact with the recomputed DEG lists. DEET, available through CRAN and RShiny, systematically queries which of the recomputed DEG lists share similar genes, pathways, and TF targets to their own gene lists. DEET identifies relevant studies based on shared results with the user's gene lists, aiding in hypothesis generation and data-driven literature review.

Decreased left heart flow in fetal lambs causes left heart hypoplasia and pro-fibrotic tissue remodeling.

Low blood flow through the fetal left heart is often conjectured as an etiology for hypoplastic left heart syndrome (HLHS). To investigate if a decrease in left heart flow results in growth failure, we generate left ventricular inflow obstruction (LVIO) in mid-gestation fetal lambs by implanting coils in their left atrium using an ultrasound-guided percutaneous technique. Significant LVIO recapitulates important clinical features of HLHS: decreased antegrade aortic valve flow, compensatory retrograde perfusion of the brain and ascending aorta (AAo) from the arterial duct, severe left heart hypoplasia, a non-apex forming LV, and a thickened endocardial layer. The hypoplastic AAo have miRNA-gene pairs annotating to cell proliferation that are inversely differentially expressed by bulk RNA-seq. Single-nucleus RNA-seq of the hypoplastic LV myocardium shows an increase in fibroblasts with a reciprocal decrease in cardiomyocyte nuclei proportions. Fibroblasts, cardiomyocytes and endothelial cells from hypoplastic myocardium have increased expression of extracellular matrix component or fibrosis genes with dysregulated fibroblast growth factor signaling. Hence, a severe sustained ( ~ 1/3 gestation) reduction in fetal left heart flow is sufficient to cause left heart hypoplasia. This is accompanied by changes in cellular composition and gene expression consistent with a pro-fibrotic environment and aberrant induction of mesenchymal programs.

Conserved regulatory logic at accessible and inaccessible chromatin during the acute inflammatory response in mammals.

The regulatory elements controlling gene expression during acute inflammation are not fully elucidated. Here we report the identification of a set of NF-κB-bound elements and common chromatin landscapes underlying the acute inflammatory response across cell-types and mammalian species. Using primary vascular endothelial cells (human/mouse/bovine) treated with the pro-inflammatory cytokine, Tumor Necrosis Factor-α, we identify extensive (~30%) conserved orthologous binding of NF-κB to accessible, as well as nucleosome-occluded chromatin. Regions with the highest NF-κB occupancy pre-stimulation show dramatic increases in NF-κB binding and chromatin accessibility post-stimulation. These 'pre-bound' regions are typically conserved (~56%), contain multiple NF-κB motifs, are utilized by diverse cell types, and overlap rare non-coding mutations and common genetic variation associated with both inflammatory and cardiovascular phenotypes. Genetic ablation of conserved, 'pre-bound' NF-κB regions within the super-enhancer associated with the chemokine-encoding CCL2 gene and elsewhere supports the functional relevance of these elements.

Epidemiology and outcome analysis of facial burns: A retrospective multicentre study 2011-2015.

BACKGROUND: The head and neck regions are frequent sites of burns, but few studies have analysed and reported the epidemiology of facial burns. As the face is the centre of one's identity and persona, facial injuries often result in physical and psychological morbidity. The aim of this article is to describe the epidemiology and outcome of facial burns in China and to suggest future preventive strategies. METHODS: This retrospective analysis included all patients with facial burns in a database at eight institutions from 2011-2015. The data collected included sex, age, month distribution, aetiology, location, presence of inhalation injury, total burn surface area, burn surface area with full-thickness and outcome including Post-traumatic stress disorder Checklist-Civilian Version scores and mortality. SPSS 19.0 software was used to analyse the data. RESULTS: A total of 1126 patients were included; 65.63% (739) had facial burns, of which 546 (73.88%) were male patients and 193 (26.12%) were female patients. Predictors of facial burns were being of male sex, working-related place, flame burns, total body surface area, and full-thickness burns. In addition, total body surface area and full-thickness burns increased the risk of poor prognosis for post-traumatic stress disorder and mortality. CONCLUSIONS: Facial burns benefit not only the healing of wound, but also the prevention of their incidence and PTSD symptom. This study may contribute to the elaboration of strategies to prevent facial burns and the establishment of a nationwide burn database in China.

Highly Combinatorial Genetic Interaction Analysis Reveals a Multi-Drug Transporter Influence Network.

Many traits are complex, depending non-additively on variant combinations. Even in model systems, such as the yeast S. cerevisiae, carrying out the high-order variant-combination testing needed to dissect complex traits remains a daunting challenge. Here, we describe "X-gene" genetic analysis (XGA), a strategy for engineering and profiling highly combinatorial gene perturbations. We demonstrate XGA on yeast ABC transporters by engineering 5,353 strains, each deleted for a random subset of 16 transporters, and profiling each strain's resistance to 16 compounds. XGA yielded 85,648 genotype-to-resistance observations, revealing high-order genetic interactions for 13 of the 16 transporters studied. Neural networks yielded intuitive functional models and guided exploration of fluconazole resistance, which was influenced non-additively by five genes. Together, our results showed that highly combinatorial genetic perturbation can functionally dissect complex traits, supporting pursuit of analogous strategies in human cells and other model systems.

Epidemiologic and clinical characteristics of severe burn patients: results of a retrospective multicenter study in China, 2011-2015.

BACKGROUND: Severe burns injury is a serious pathology, leading to teratogenicity and significant mortality, and it also has a long-term social impact. The aim of this article is to describe the hospitalized population with severe burns injuries in eight burn centers in China between 2011 and 2015 and to suggest future preventive strategies. METHODS: This 5-year retrospective review included all patients with severe burns in a database at eight institutions. The data collected included gender, age, month distribution, etiology, location, presence of inhalation injury, total burn surface area, depth of the burn, the length of hospitalization, and mortality. SPSS 19.0 software was used to analyze the data. RESULTS: A total of 1126 patients were included: 803 (71.3%) male patients and 323 (28.7%) female patients. Scalds were the most common cause of burns (476, 42.27%), followed by fire (457, 40.59%). The extremities were the most frequently affected areas, followed by the trunk. The median length of hospitalization was 30 (15, 52) days. The overall mortality rate was 14.21%. CONCLUSIONS: Although medical centers have devoted intensive resources to improving the survival rates of burn patients, expenditures for prevention and education programs are minimal. Our findings suggest that more attention should be paid to the importance of prevention and the reduction of injury severity. This study may contribute to the establishment of a nationwide burn database and the elaboration of strategies to prevent severe burns injury.

The newly identified CpG-N ODN208 protects mice from challenge with CpG-S ODN by decreasing TNF-alpha release.

Administration of an excess of oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG-S ODNs) may induce systemic inflammatory response syndrome (SIRS) and sepsis. Therefore, it is important to develop neutralizing CpG ODNs (CpG-N ODNs), which can be used to reduce the release of cytokines induced by the presence of CpG-S ODNs. In the present study, CpG-N ODN208 (5'-TGCCGCGGCAGA-3'), a neutralizing twelve-oligodeoxynucleotide molecule recently identified in our laboratory, inhibited TNF-alpha release from human peripheral blood mononuclear cells (hPBMCs) and murine RAW264.7 cells induced by CpG-S ODN exposure in a dose- and time-dependent manner. Flow cytometry revealed that CpG-N ODN208 decreased cell-surface binding and internalization of 6-FAM-CpG-S ODN. However, the decreased cell-surface binding and internalization of CpG-S ODN could not completely account for the decreased TNF-alpha release. RT-PCR experiments revealed that CpG-N ODN treatment could down-regulate the CpG-S ODN-induced upregulation of Toll-like receptor 9 (TLR9) mRNA expression. This finding suggested that the decreased cytokine release following CpG-N ODN treatment might be related to decreased TLR9 mRNA expression. In in vivo experiments, no protection was found when the ratio of CpG-N ODN to CpG-S ODN delivered to mice was 3:1. However, at a 5:1 ratio, CpG-N ODN208 could protect mice from an ordinarily lethal dose of CpG-S ODN. Furthermore, we found that CpG-N ODN208 treatment decreased serum TNF-alpha levels in mice injected with sublethal doses of CpG-S ODN whether the CpG-N ODN208 was added prior to or concurrent with the CpG-S ODN. Our results demonstrated that CpG-N ODN-mediated protection against a lethal challenge by CpG-S ODN was associated with the reduction of TNF-alpha release.

Human Trefoil Factor 3 induces the transcription of its own promoter through STAT3.

Human trefoil factor 3 (hTFF3) is a small peptide of potential therapeutic value. The mechanisms underlying the transcriptional regulation of hTFF3 remain unclear. The purpose of this study was to identify the core functional elements for the self-induction action of hTFF3 and transcription factors. First, truncated promoters were constructed to identify the functional regions of the hTFF3 promoter. Next, point mutation, chromatin immunoprecipitation, RNA interference, and gene overexpression experiments were performed to analyze the transcriptional binding sites responsible for the self-induced transcription of hTFF3. Our results revealed the -1450 bp to -1400 bp fragment of the hTFF3 promoter was the functional region for the self-induction action of hTFF3. Bioinformatics analysis confirmed that a STAT3 binding site is present in the -1417 bp to -1409 bp region. Subsequently, site-directed mutagenesis analysis determined that this STAT3 binding site was critical for the self-induction effect of hTFF3. ChIP experiments confirmed that STAT3 binds to the hTFF3 promoter. STAT3 overexpression and knockdown experiments revealed that STAT3 enhanced the self-induction effect and the expression of hTFF3. This study confirmed that hTFF3 exhibits self-induction action, and that STAT3 is the key transcription factor to maintain the function of self-induction.

Lipopolysaccharide could be internalized into human peripheral blood mononuclear cells and elicit TNF-alpha release, but not via the pathway of toll-like receptor 4 on the cell surface.

Lipopolysaccharide (LPS), the principal component of the outer membrane of Gram-negative bacteria, stimulates various cell types to release numerous proinflammatory mediators such as TNF-alpha, IL-6 and IL-12, which may damage cells and lead to organ injury, even sepsis and septic shock. Toll-like receptor 4 (TLR4) has been identified as the receptor involved in the recognition of LPS, but the role of LPS uptake in activating signal transduction remains controversial. In the present study, TNF-alpha was used as a marker of macrophages/ monocytes activated by LPS, and CQ was used as an inhibitor of endosome mature in order to definitude what stage of the signal transduction elicited by LPS was interrupted. We found that there indeed existed internalization of LPS and internalization partially participated in LPS signaling since CQ inhibited cytokine release, and decreased accumulation of FITC-LPS in hPBMCs. In contrast, anti-hTLR4 antibody could decrease cytokine release, but had no inhibition on accumulation of FITC-LPS. This result revealed that inhibition of cytokine release was related to reduction of FITC-LPS accumulation in the cells. But TLR4 on the cell surface couldn't participate in internalization of LPS. Thus, LPS signaling and internalization couldn't be viewed as mutually independent processes.

Cloning and characterization of the human trefoil factor 3 gene promoter.

Human trefoil factor 3 (hTFF3) is a small-molecule peptide with potential medicinal value. Its main pharmacological function is to alleviate gastrointestinal mucosal injuries caused by various factors and promote the repair of damaged mucosa. However, how its transcription is regulated is not yet known. The aim of this study was to clone the hTFF3 gene promoter region, identify the core promoter and any transcription factors that bind to the promoter, and begin to clarify the regulation of its expression. The 5' flanking sequence of the hTFF3 gene was cloned from human whole blood genomic DNA by PCR. Truncated promoter fragments with different were cloned and inserted into the pGL3-Basic vector to determine the position of the core hTFF3 promoter. Transcription element maintaining basic transcriptional activity was assessed by mutation techniques. Protein-DNA interactions were analyzed by chromatin immunoprecipitation (ChIP). RNA interference and gene over-expression were performed to assay the effect of transcription factor on the hTFF3 expression. The results showed that approximately 1,826 bp of the fragment upstream of hTFF3 was successfully amplified, and its core promoter region was determined to be from -300 bp to -280 bp through analysis of truncated mutants. Mutation analysis confirmed that the sequence required to maintain basic transcriptional activity was accurately positioned from -300 bp to -296 bp. Bioinformatic analysis indicated that this area contained a Sp1 binding site. Sp1 binding to the hTFF3 promoter was confirmed by ChIP experiments. Sp1 over-expression and interference experiments showed that Sp1 enhanced the transcriptional activity of the hTFF3 promoter and increased hTFF3 expression. This study demonstrated that Sp1 plays an important role in maintaining the transcription of hTFF3.

Recombinant adenovirus-mediated intestinal trefoil factor gene therapy for burn-induced intestinal mucosal injury.

Intestinal trefoil factor (ITF) is a small polypeptide with potential medical values whose main pharmacological effects are to alleviate gastrointestinal mucosal injury caused by various injury factors and promote the repair of damaged mucosa. However, its low yield limits its application. The purpose of our study was to construct a recombinant adenoviral vector containing the hITF gene and observe the therapeutic effect of burn-induced intestinal mucosal injury using in vitro and in vivo analysis. First, a recombinant shuttle plasmid was constructed by ligating a pAdTrack-CMV vector with a full-length hITF gene containing a signal peptide and the mature peptide, followed by the recombinant Ad-hITF adenovirus vector after linearization and homologous recombination with the backbone plasmid in the competent BJ5183 strain. Second, the hITF expression level was detected using reverse transcription polymerase chain reaction and western blotting after Ad-hITF infection of colon cancer HT-29 cells. The recombinant adenovirus significantly promoted cell migration in an in vitro wounding model. Finally, we confirmed that the recombinant adenovirus could significantly expedite the healing of intestinal mucosal injury after establishing a mouse model in which severe burns were stimulated and the recombinant adenovirus was delivered by intragastric injection. In summary, we constructed a recombinant adenoviral vector containing the hITF gene and confirmed its role in promoting repair of the intestinal mucosa. Our study provides a novel way to treat burn-induced intestinal mucosal injury.

[Effects of glutamine combined with ulinastatin on inflammatory response of patients with severe burn injury].

OBJECTIVE: To observe the effects of glutamine combined with ulinastatin on inflammatory response of patients with severe burn injury. METHODS: Sixty patients with severe burn injury admitted to our burn wards from January 2010 to December 2011 conforming to the study criteria were divided into control group (C, n = 20), glutamine group (G, n = 20), and glutamine combined with ulinastatin group (G + U, n = 20) according to the random number table. Another 10 healthy volunteers were chosen as normal control group (NC). Isonitrogenous and isocaloric nutrition supports were given to patients in groups C, G, and G + U from post burn day (PBD) 2. 0.3 g/kg protein in the form of glutamine dipeptide was given to patients in group G for 10 days. 0.3 g/kg protein was given to patients in group G + U for 10 days with the same amount of glutamine dipeptide as that in group G, followed by intravenous injection of 100 kU ulinastatin (once per 8 hours) for 7 days during 10 days. The nitrogen concentration of 24 h urine was determined with Kieldahl nitrogen determination method, and nitrogen balance was calculated one day before treatment and ten days after treatment. Meanwhile, the levels of D-lactate in serum was determined by colorimetric method, the levels of diamine oxidase (DAO), TNF-α, and IL-6 by enzyme-linked immunosorbent assay, and LPS level by kinetic turbidimetric assay with TAL. Above-mentioned indexes were also examined in group NC. The wound healing rate on PBD 30, total hospital stay days, and the incidence of burn sepsis of all burn patients were recorded. Data were processed with one-way analysis of variance, LSD test, t test, and chi-square test. RESULTS: Compared with that in group C [(-5.40 ± 1.67) g/d], nitrogen balance in group G was significantly increased ten days after treatment [(-1.35 ± 0.59) g/d, P < 0.01]. The serum levels of D-lactate, DAO, LPS, TNF-α, and IL-6 in group G ten days after treatment were significantly lower than those in group C (P < 0.05 or P < 0.01). No statistically significant difference was observed in nitrogen balance and the serum levels of D-lactate, DAO between group G + U and group G (P values all above 0.05). The serum levels of LPS, TNF-α, and IL-6 in group G + U ten days after treatment were respectively (0.167 ± 0.064) EU/mL, (43 ± 14) pg/mL, (139 ± 23) pg/mL, which were significantly lower than those in group G [(0.240 ± 0.079) EU/mL, (59 ± 8) pg/mL, (195 ± 31) pg/mL, respectively, P < 0.05 or P < 0.01]. The would healing rate on PBD 30 and total hospital stay days in group G were respectively higher and shorter than those in group C (P values all below 0.01), but no statistically significant difference in the incidence of burn sepsis was found between them (P > 0.05). The would healing rate on PBD 30 in group G+U [(96 ± 4)%] was enhanced, and total hospital stay days [(41 ± 4) d] were lowered than those in group G [(88 ± 7)%, (49 ± 5)d, P values all below 0.01]. The incidence of burn sepsis of patients in group G + U (5%) was significantly lower than that in group C (35%, χ(2) = 6.234, P < 0.05). CONCLUSIONS: Glutamine combined with ulinastatin treatment can alleviate damage to intestine after severe burn injury, lower the serum level of inflammatory cytokines, promote wound healing, and reduce the incidence of burn sepsis.

The antimalarial artemisinin synergizes with antibiotics to protect against lethal live Escherichia coli challenge by decreasing proinflammatory cytokine release.

In the present study artemisinin (ART) was found to have potent anti-inflammatory effects in animal models of sepsis induced by CpG-containing oligodeoxy-nucleotides (CpG ODN), lipopolysaccharide (LPS), heat-killed Escherichia coli 35218 or live E. coli. Furthermore, we found that ART protected mice from a lethal challenge by CpG ODN, LPS, or heat-killed E. coli in a dose-dependent manner and that the protection was related to a reduction in serum tumor necrosis factor alpha (TNF-alpha). More significantly, the administration of ART together with ampicillin or unasyn (a complex of ampicillin and sulbactam) decreased mortality from 100 to 66.7% or 33.3%, respectively, in mice subjected to a lethal live E. coli challenge. Together with the observation that ART alone does not inhibit bacterial growth, this result suggests that ART protection is achieved as a result of its anti-inflammatory activity rather than an antimicrobial effect. In RAW264.7 cells, pretreatment with ART potently inhibited TNF-alpha and interleukin-6 release induced by CpG ODN, LPS, or heat-killed E. coli in a dose- and time-dependent manner. Experiments utilizing affinity sensor technology revealed no direct binding of ART with CpG ODN or LPS. Flow cytometry further showed that ART did not alter binding of CpG ODN to cell surfaces or the internalization of CpG ODN. In addition, upregulated levels of TLR9 and TLR4 mRNA were not attenuated by ART treatment. ART treatment did, however, block the NF-kappaB activation induced by CpG ODN, LPS, or heat-killed E. coli. These findings provide compelling evidence that ART may be an important potential drug for sepsis treatment.

[Experimental study on the antagonistic activity of cationic multi-peptide mastoparan-1 against lipopolysaccharide].

OBJECTIVE: To explore the mechanism of cationic multi-peptide mastoparan-1 (MP-1) on the protection of mice from lipopolysaccharide (LPS) challenge. METHODS: Thirty Kunming mice were divided randomly into MP-1, injury, protection groups with 10 mice in each group. The mice in MP-1 group were injected with 3 mg/kg MP-1 by tail vein, while those in injury group were injected with 20 mg/kg LPS by tail vein, and those in protection group 3 mg/kg MP-1 within 20 seconds after 20 mg/kg LPS injection were injected. The effects of MP-1 on the protection of mice from LPS challenge were observed. In vitro, the affinity of MP-1 and PMB to LPS was compared by biosensor and FAST fit construct and expressed as Kd. And the neutralizing activity of MP-1 and PMB in dose of 5, 10, 20, 40 micromol/L on LPS (2 microg/L) was detected by dynamic turbidimetric limulus test with LPS neutralizing 0 micromol/L MP-1 and PMB as control. The mRNA expression levels of TLR4, TNF-alpha and IL-6 in murine peritoneal macrophages (PM phi) after exposure to LPS (100 ng/ml) were assayed by RT-PCR. RESULTS: MP-1 could significantly protect mice from LPS challenging with protection rate of 90%. In vitro, MP-1 had a high affinity (Kd value: 484.0 nmol/L) and neutralizing ability with LPS, but it was lower than that of PMB (Kd value: 18.9 nmol/L). The neutralizing effect of 20 and 40 micromol/L MP-1 was obviously stronger than that in 0 micromol/L (P < 0.01). MP could obviously inhibit the expression of TLR4, TNF-alpha and IL-6 mRNA in LPS-stimulated murine PM phi. CONCLUSION: MP-1 can evidently protect mice from lethal LPS challenge, and the mechanism might be related to the activity of MP-1 which binding and neutralizing LPS, blocking the combination LPS with its receptors. So the murine macrophage activation induced by LPS was inhibited.