Peifang Zhu

Effects of haplotypes in the interleukin 1beta promoter on lipopolysaccharide-induced interleukin 1beta expression.

ABSTRACT Previous studies have indicated that there are 3 common haplotypes composed of the −1470, −511, and −31 loci in the interleukin 1&bgr; (IL-1&bgr;) promoter in the Chinese population. The purpose of this study was to investigate the relationship between these haplotypes and lipopolysaccharide (LPS)-stimulated IL-1&bgr; expression by whole blood leukocytes in vitro and to evaluate the effects of these haplotypes on IL-1&bgr; gene transcription. Genomic DNAs were obtained from 105 healthy subjects. The genotypes at the 3 sites of the IL-1&bgr; promoter were determined by restriction fragment length polymorphism analysis. Haplotype frequency was evaluated by using the Arlequin software. Plasma IL-1&bgr; level was measured by enzyme-linked immunosorbent assay. The transcriptional activity of the haplotypes was determined by in vitro reporter gene. The results indicated that after the exposure to LPS, whole blood leukocytes from subjects with the homozygous haplotype −1470G, −511C, and −31T (G-C-T) produced more IL-1&bgr; in vitro than those from subjects with haplotype −1470C, −511T, and −31C (C-T-C) and that the transcriptional activity of the haplotype G-C-T was also higher than that of the haplotype C-T-C. It is suggested that the haplotypes of the IL-1&bgr; promoter influence the expression and transcriptional activity of the IL-1&bgr; gene and that the upregulation of IL-1&bgr; gene expression after LPS exposure in subjects with haplotype G-C-T may be due to an increased transcriptional activity of the haplotype.

Kinetics of mitogen-activated protein kinase family in lipopolysaccharide-stimulated mouse Kupffer cells and their role in cytokine production.

This study was designed to systemically investigate the kinetics of extracellular signal-regulated kinase (ERK) 1/2, p54 c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinases (MAPKs) in lipopolysaccharide (LPS)-stimulated Kupffer cells (KC) simultaneously at the levels of protein expression, phosphorylation, and kinase activity, respectively, and their role in mediating pro- and anti-inflammatory cytokines. The protein expression, phosphorylation, and activities of these MAPKs in LPS-stimulated primary mouse KCs were determined with SDS-PAGE and western blotting using nonphosphorylated or phosphospecific antibodies or their corresponding substrates. The levels of TNF-&agr; and IL-10 in culture supernatants were measured with ELISA kits. The results revealed that LPS stimulation, although not up- or downregulating the protein expression of ERK1/2, p54JNK, and p38 MAPKs in KCs, could induce rapid and significant activation of these kinases, with parallel profiles of changes in both phosphorylation and kinase activities. Although ERK1/2, p54JNK, and p38 kinases in LPS-stimulated KCs have similar kinetics of activation, the activation of ERK1/2 and p38 kinases was the most prominent. Inhibition of p38 MAPK with SB203580 inhibited the production of TNF-&agr; and IL-10 by LPS-stimulated KCs, whereas blockade of ERK1/2 with PD98059 could reduce TNF-&agr; production, but did not affect IL-10 production. Furthermore, PD 98059 and SB203580 had an additive effect on TNF-&agr; production, but PD98059 did not augment the SB203580-induced inhibition of IL-10 production. These data indicate that LPS stimulation, although not inducing any change in protein expression, results in rapid activation of ERK1/2, p54JNK, and p38 kinases in KCs, and that they may have different importance in the regulation of pro- and anti-inflammatory responses by LPS-stimulated KCs.

Identification of interleukin-6 promoter polymorphisms in the Chinese Han population and their functional significance.

Objective:Interleukin-6 (IL-6) is a pivotal cytokine in both innate and adaptive immunity. Several polymorphisms in the IL-6 promoter have been reported in Western populations. However, little is known about their occurrence in the Chinese population. The functionality of IL-6 promoter polymorphisms remains controversial. Design:Genetic, functional, and association studies. Setting:National key laboratory of trauma and departments of traumatic surgery in two teaching hospitals. Subjects:A total of 348 healthy blood donors and 105 patients with major trauma. Interventions:None. Measurements and Main Results:Identification of polymorphisms in the IL-6 promoter was performed using sequencing and restriction fragment length polymorphism methods. Their functionality was assessed by observation of transcription activity, IL-6 production, and their clinical relevance in 105 patients with major trauma. Only one variant (C-572G) was identified in IL-6 promoter in Chinese Han population. This polymorphism was associated with IL-6 production by peripheral leukocytes in response to ex vivo lipopolysaccharide stimulation in an allele-dose-dependent effect. The C→G variation at position -572 could reduce transcriptional activity of the IL-6 promoter as shown in both U-937 and K562 cell lines. Moreover, the -572 polymorphism was associated with lower risk of sepsis in major trauma patients. Conclusions:The -572 polymorphism, a unique variation in the IL-6 promoter in the Chinese Han population, may be used as a relevant risk estimate for sepsis in trauma patients.

Clinical relevance of IL-1beta promoter polymorphisms (-1470, -511, and -31) in patients with major trauma.

Recent reports have indicated that IL-1&bgr; is excessively released into the circulation during sepsis, and the expression level is closely correlated with the clinical course. Polymorphisms in the promoter region of IL-1B have been shown to affect LPS-induced IL-1&bgr; transcription in vitro and IL-1&bgr; plasma levels in healthy adults and to confer susceptibility to inflammatory diseases. However, it is not clear whether they confer susceptibility to sepsis after major trauma. The aim of this study was to search for association of polymorphisms (-1470G/C, -511T/C, and -31C/T) in the IL-1B gene promoter with the susceptibility to sepsis in a cohort of 238 major trauma patients. Genotyping of each patient for the three single-nucleotide polymorphisms was performed by restriction fragment length polymorphism-polymerase chain reaction method. Multivariate logistic regression analysis showed that the -1470 and -31 polymorphisms were associated with IL-1&bgr; production by peripheral leukocytes in response to ex vivo LPS stimulation in an allele dose-dependent manner. Moreover, trauma patients carrying the -1470G or -31T alleles were more likely to develop sepsis compared with those with the -1470C or -31C allele (P = 0.014 and P = 0.038, respectively). Of the eight possible haplotypes composed of the three loci, the GCT and CTC haplotypes were associated with significantly higher and lower IL-1&bgr; secretion (P = 0.005 and P = 0.035, respectively). Moreover, the GCT haplotype imparted higher risk of sepsis after severe injury (P = 0.04; odds ratio, 1.131; 95% confidence interval, 1.013-1.678). GCT homozygote patients also showed higher multiple organ dysfunction scores than CTC homozygote patients (P = 0.048). These data suggest that the IL-1&bgr; promoter polymorphisms -1470G/C, -511T/C, and -31C/T may be functional both in vitro and in vivo. It may be possible to use these polymorphisms as relevant risk estimates for sepsis in trauma patients.

Functional Significance Of The tlr4 /11367 Polymorphism Identified In Chinese Han Population

Toll-like receptor 4 (TLR4) is the central signaling receptor for lipopolysaccharide (LPS) in mammals. This study was designed to investigate the functional significance of the G11367C polymorphism, which is a novel variant we identified in the 3&vprime; untranslated region of TLR4 gene in Chinese Han population. Three hundred seventy healthy volunteers were selected. The TLR4/11367 polymorphism was genotyped using single-tube bidirectional allele-specific amplification method. The TLR4 protein expression on peripheral leukocytes and plasma tumor necrosis factor &agr; levels were determined by means of flow cytometry and enzyme-linked immunosorbent assay. The post-transcriptional effect of the 11367 polymorphism was evaluated by means of reporter gene assay and real-time quantitative polymerase chain reaction. The G11367C polymorphism is a common allele in Chinese Han population, with minor allele frequency of 14.7%. In response to ex vivo LPS stimulation, the TLR4 expression on the surface of peripheral leukocytes and the plasma tumor necrosis factor &agr; levels were significantly lower in carriers of 11367C variant allele than in carriers of 11367G allele. This association was allele dose dependent. We also found that the activity and the mRNA expression of luciferase was significantly smaller in human embryonic kidney 293 cells transfected with construct containing 11367C allele than in those transfected with construct containing 11367G allele. Together, these results suggest that the TLR4/11367 polymorphism may be a functional single nucleotide polymorphism, which could attenuate the LPS-induced transmembrane signaling through the alteration of post-transcriptional regulation of 3&vprime; untranslated region and target gene expression.

Plasma cytokines and endotoxin levels in patients with severe injury and their relationship with organ damage

In 17 patients plasma TNF-alpha and IL-8 were assayed with enzyme-linked immunosorbent assay. IL-6 activity in plasma was determined by bioassay with IL-6-dependent cell line 7TD1. The limulus amoebocyte lysate chromogenic test was used for plasma endotoxin assay. Plasma cytokine levels in injured patients were significantly increased. Plasma TNF-alpha was shown to be increased earlier, while an increase in plasma IL-6 and IL-8 levels occurred late, all of which were shown to be significantly positively correlated with ISS, cardiac and hepatic enzyme activities, and index of renal function. In addition, obvious endotoxaemia occurred at an early stage of injuries, which was respectively significantly correlated with ISS and plasma TNF-alpha, IL-6 and IL-8 levels. Severe injuries could induce increased successive release of TNF-alpha, IL-6 and IL-8, and obvious endotoxaemia. The post injury release of cytokines might be related to endotoxaemia, and may play an important role in the development of organ damage after injury.

Effect Of Hemorrhagic Shock On Endotoxin-inducing Tnf Production And Intra-tissue Lipopolysaccharide-binding Protein mrna Expression And Their Relationship

In order to further elucidate effect of hemorrhagic shock on endotoxin-inducing cytokine production, the present study was designed to investigate the production of tumor necrosis factor α (TNFα) induced by low-dose (1 μg/kg) of lipopolysaccharide (LPS) and its cellular sources after hemorrhagic shock (HS) in rats. With combination of expression of lipopolysaccharide-binding protein (LBP) mRNA in the liver, lungs, and kidneys, we further analyzed a possible mechanism for increasing sensitivity to LPS by shock. We found in vivo that plasma TNFα levels in the HS+LPS group were 20-fold higher than those in the HS group (p < .01) and 2.7-fold higher than those in the LPS group (p < .05). It was shown in vitro that the capacity of the peripheral white blood cells to produce TNFα in response to LPS stimulation was significantly decreased by 126% (p < .01) and 57% (p < .05) compared with the pre-shock levels and sham group, respectively, at the end of resuscitation following shock, and still markedly inhibited 3 h after resuscitation, while the capacity of hepatic Kupffers cells to produce TNFα was significantly increased by 110% compared with the sham group (p < .01) after shock and resuscitation. Results from RT-PCR showed that expression of LBP mRNA in the liver, lungs, and kidneys was increased after shock and resuscitation. It is suggested that hemorrhagic shock could significantly strengthen endotoxin to induce TNFα production, which might be due to up-regulation of LBP expression in tissues after shock, and the tissue macrophage population may be the main source for cytokine production in shock.

Intrapulmonary Expression of Scavenger Receptor and CD14 and Their Relation to Local Inflammatory Responses to Endotoxemia in Mice

This study was first designed to investigate systematically the kinetics of surface expression of scavenger receptors (SRs) and CD14 on alveolar macrophages in vivo and in vitro and their relation with local pro- and antiinflammatory responses in endotoxemia. The expression of SR and CD14 in lungs was down- and up-regulated, respectively, in the presence of endotoxemia, which might be due to decreased expression of SR and increased expression of CD14 on the surface of the resident macrophages. Down-regulation of SRs on alveolar macrophages not only induces decreased defensive function of the macrophages, it also enhances lipopolysaccharide (LPS)-induced activation of alveolar macrophages possibly through increasing LPS binding to CD14. Although CD14 is a key receptor responsible for LPS to activate macrophages, both phospholipase C and anti-CD14 antibody can completely inhibit activation of alveolar macrophages initiated by only LPS 1 ng/ml, as determined by tumor necrosis factor-{alpha} (TNF{alpha}) production, but it does not significantly change TNF{alpha} release upon cell stimulation by LPS 10 {mu}g/ml. There was an intrinsic relation of enhanced intrapulmonary pro- and antiinflammatory responses with changes in SR and CD14 expression, which suggests that the down-regulation of SR and up-regulation of CD14 might be an important mechanism for the lung to change from a defense organ to an effector organ during sepsis.

Intra-hepatic expression of scavenger receptor and CD14 and their relationship with local inflammatory responses in endotoxemia in mice.

Our objective was to investigate the expression of scavenger receptor (SR) and CD14 in the liver and their relationship with local anti-inflammatory and proinflammatory responses in endotoxemia in order to uncover the mechanism for the liver to turn into effector organ from defense one at the level of cell receptors in sepsis. Mouse models of endotoxemia of different severity were reproduced by injection of different doses of lipopolysaccharide (LPS) via tail vein. Expression of SR and CD14 in the liver was assayed by immunohistochemistry and was then analyzed with an image analysis system. The levels of TNFalpha, IL-6, IL-4, and IL-10 in liver tissue were determined with ELISA. Expression of SR in the liver in the high-dose group was markedly decreased 1 h after injection of LPS, and also in low- and medium-dose groups at 3 h. The expression of SR in the liver in the three groups was shown to be progressively decreased with the time prolonged. There was significant difference in average optical density (OD) values of SR among the three groups. The expression of CD14 in the liver in the three groups was shown to be significantly increased 1 h after injection of LPS, and much more with the time prolonged. But there was no significant difference in OD values of CD14 among the three groups. The contents of intrahepatic proinflammatory mediators TNFalpha and IL-6 and anti-inflammatory mediators IL-4 and IL-10 were successively significantly increased after injection of LPS. The release of anti-inflammatory mediators was shown to be later than that of proinflammatory mediators. Correlation analysis indicated that there was negative correlation between expression of SR and CD14, and that changes of TNFalpha, IL-6, IL-4, and IL-10 levels in liver tissues were correlated significantly positively with OD values of CD14 and negatively with OD values of SR. Expression of SR in the liver was shown to be progressively decreased, and that of CD14 increased in endotoxemia, which was closely related to the uncontrolled inflammatory response in liver. This might be an important mechanism for the liver to turn into effector organ from defense one in sepsis.

Distributions of glucocorticoid receptor gene polymorphisms in a Chinese Han population and associations with outcome after major trauma.

AIM To investigate in a Chinese population the occurrence of polymorphisms Bcl I, N363S and ER22/23EK in the glucocorticoid receptor and their association with outcome of trauma. METHODS In all, 266 healthy volunteers and 95 victims of major trauma were recruited. The presence of glucocorticoid receptor polymorphisms (ER22/23EK, N363S and Bcl I) was sought by restriction fragment length polymorphism analysis. The injured group were monitored as to respiratory, renal, hepatic, cardiovascular, haematological and central nervous functions. The association was determined between polymorphisms and the development of multiple organ dysfunction syndrome and sepsis after trauma. RESULTS Only the Bcl I polymorphism was identified. The frequency of its G allele was 23.5% among volunteers and 26.3% among casualties. There were no significant differences in MOD score or sepsis rate between participants classified according to genotype. CONCLUSIONS Only the Bcl I polymorphism of the glucocorticoid receptor gene is common in the Chinese Han population; it may not influence the development of complications following major trauma.