核受体在免疫反应中的调控作用研究进展

核受体是众多转录调节因子中的一员。其调控包括内稳态、生殖、发育及代谢等方面的功能。众多研究发现,多数核受体家族成员在调节炎症和免疫中发挥重要作用,但是其具体的作用机制仍是未知的。进一步阐明核受体在免疫反应中的调控作用有利于了解免疫反应和机体代谢之间的相互联系,并为这些免疫和代谢性疾病的治疗提供新的靶点。     

Status of bacterial colonization, Toll-like receptor expression and nuclear factor-kappa B activation in normal and diseased human livers

Epidemiological data on bacterial translocation (BT), colonization and inflammation in normal human livers is lacking. In this study we investigated the status of bacterial colonization and inflammation in the normal, cirrhotic primary biliary cirrhosis (PBC), and nonalcoholic steatohepatitis (NASH) human liver tissues. Comparatively normal livers showed increased bacterial colonization than PBC and NASH. We analyzed mRNA levels of Toll-like receptors (TLR) 2 and TLR4, and protein levels of TLR4. Phosphorylated IKKα (pIKKα) protein estimation served as a marker for nuclear factor-kappa B (NF-κB) activation. In spite of the increased bacterial colonization in normal liver tissues, lower levels of TLR2/4 mRNA and TLR4 and pIKKα proteins were found compared to PBC and NASH indicating the maintenance of suppressed inflammation and immune tolerance in normal livers. To our knowledge, this is the first clinical evidence showing suppressed inflammation despite bacterial colonization in normal human livers thus maintaining liver immune homeostasis.     

Role of Toll-like receptor 4 in hyperoxia-induced lung inflammation in mice

Objective: Prolonged exposure to hyperoxia causes lung inflammation, but the role of Toll-like receptor 4 (TLR4) in hyperoxia-induced signal transduction remains unclear. Material or subjects: We evaluated neutrophil accumulation, signal transduction and cytokine production during hyperoxia, comparing TLR4 mutant (C3H/HeJ) and wild type (C3H/HeN) mice. Methods: The mice were exposed to 80% oxygen in a hyperoxic chamber for 0 (control), 48, or 96 h. After the exposure, bronchoalveolar lavage (BAL) was performed for differential cell counting and cytokine measurement. In lung homogenate, activation of NF-κB and STAT1 was also examined. Results: In C3H/HeJ mice, hyperoxia-induced neutrophil accumulation in BAL fluid was significantly decreased compared with C3H/HeN. Hyperoxia for 96 h caused NF-κB translocation in C3H/HeN mice, which was significantly attenuated in C3H/HeJ mice (p < 0.05). In contrast, STAT1 activation occurred as early as after 48 h of oxygen exposure, which did not differ between the two strains. The levels of TNF-α, IL-6, and KC in BAL fluid were increased after oxygen exposure, which was suppressed by the lack of TLR4 signaling. Conclusion: These results suggest that TLR4-dependent NF-kB activation may be an important process of the upregulation of proinflammatory mediators and subsequent neutrophil accumulation into the lung during hyperoxia. Received 21 March 2007; accepted without revision by G. Wallace 11 April 2007     

WhatSAP — 2B4 sends mixed messages in the absence of SAP

2B4 (CD244), a member of the SLAM‐related receptor family, has important immuno‐regulatory functions including coactivating the cytotoxicity and cytokine secretion of NK cells. Immune modulation by 2B4 is dependent on the small intracellular signaling molecule SAP. In patients suffering from X‐linked lymphoproliferative disease (XLP1), SAP is nonfunctional, not only abolishing the activating function of 2B4, but rendering this receptor inhibitory. In this issue of European Journal of Immunology, Meazza et al. [Eur. J. Immunol. 2014. 44: 1526–1534.] demonstrate that 2B4‐mediated inhibition in NK cells from XLP1 patients is selective. While the activation of NK cells via ITAM‐based receptors is blocked by inhibitory 2B4, DNAM‐1, and NKG2D‐dependent NK‐cell activation is not affected by SAP deficiency. These findings provide an important insight into the different defective NK‐cell functions in XLP1 patients and demonstrate the differential integration of redundant receptor signaling pathways in NK cells.     

Expression of steroid hormone receptors, their regulated proteins, and bcl-2 protein in myofibroblastoma of the breast

AIMS: To investigate the possible role of steroid hormones in the pathogenesis of myofibroblastoma (MFB) of the breast, we analysed the immunohistochemical expression of oestrogen, progesterone, androgen receptors, their regulated proteins and bcl-2 protein in a series of this rare tumour. METHODS AND RESULTS: Paraffin-embedded sections from seven cases of MFB of the breast (five male; two female) were immunohistochemically tested for the expression of oestrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), oestrogen-regulated pS2 protein, androgen-regulated prostate-specific antigen (PSA) and bcl-2 protein. Rare cases of benign spindle cell tumours or tumour-like lesions of the breast (primitive fibromatosis, inflammatory pseudotumour, muscular hamartoma) which enter into the differential diagnosis with MFB, were also investigated and compared with MFB. All cases of MFB showed a diffuse (70-90% of neoplastic cells) and strong nuclear labelling with ER and PR, whereas AR was expressed only in three cases (two men and one woman) in about 60-70% of cells. Conversely, no immunostaining was detected for the pS2 protein and PSA. bcl-2 protein immunoreactivity was found in all cases of MFB, although with a variable degree of expression. No expression for steroid hormone receptors, their regulated-proteins and bcl-2 protein was observed in the rare benign spindle cell lesions of the breast included in this study. CONCLUSION: The in-situ detection of ER, PR and AR suggests that steroid hormones and their receptors are implicated in the pathogenesis of breast MFB. The consistent demonstration of bcl-2 protein, associated with a positive ER/PR status, provides evidence that bcl-2 may be an oestrogen-regulated protein also in MFB and that probably plays a role in the tumorigenesis. Finally, we postulate that the ER/PR and bcl-2 positive immunoprofile of MFB of the breast, in contrast to the negative profile of other rare primitive benign spindle cell lesions of the breast herein studied, might be exploited as an ancillary diagnostic aid in differential diagnosis of doubtful cases.     

Some theoretical questions of the peptide and steroid hormone regulation: Part II.: The second messenger system

The "second messenger system" has been analysed regarding its possibilities for containing and transferring highly specific molecular, biological information. Very heterogeneous molecules were found behind the different - cyclase, diesterase, kinase,... - activities of the system, whereas the connection realized between them by cyclic nucleotides was very poor. So, I constructed a theoretical model mostly on the basis of real and known experimental facts to resolve this obvious contradiction and make the second messenger system adequate as a highly specific biological informational channel.     

p38丝裂原活化蛋白激酶对严重烧伤大鼠肝脏激活蛋白-1和核因子-κB的影响

目的观察严重烧伤后肝脏p38丝裂原活化蛋白激酶（mitogen—activated protein kinase，MAPK）对激活蛋白（activating protein，AP）-1和核因子（nuclear factor，NF）-κB的影响。方法采用30％TBSAⅢ度烫伤动物模型，健康成年的雄性SD大鼠24只，随机分为假烫组、烧伤对照组和烧伤＋SB203580组。观察烧伤24h后肝脏IκBα含量的变化，并采用凝胶电泳迁移率变化分析（electrophoretic mobility shift assay，EMSA）法检测肝脏AP-1和NF-κB DNA结合活性的变化。结果大鼠烧伤24h后肝脏IκBα含量明显下降（2086±684 vs 4138±1160，P〈0．05），肝脏AP-1和NF-κB DNA结合活性均显著增强，使用p38MAPK抑制剂SB203580能显著抑制肝脏AP-1 DNA结合活性的上升（469±84 vs 1306±486，P〈0．01），但对肝脏IκBα含量和NF-κB DNA结合活性的变化无明显影响。结论严重烧伤后，肝脏中活化的p38MAPK通过激活转录因子AP-1进而引起细胞因子的产生，在烧伤后肝损伤的发生中起重要作用，p38MAPK这一作用与IκBα降解引起的NF-κB DNA结合活性增强无关。     

Association of polymorphisms in TLR genes and in genes of the Toll-like receptor signaling pathway with cancer risk

Toll-like receptors (TLRs) constitute a family of receptors directly recognizing a wide spectrum of exogenous and endogenous ligands playing the key role in realization of innate and adaptive immune response, and participating in the processes of cell proliferation, survival, apoptosis, angiogenesis, tissue remodeling and repair. Polymorphisms in TLR genes may shift balance between pro- and anti-inflammatory cytokines, modulating the risk of infection, chronic inflammation and cancer. The short list of TLR polymorphisms perspective for oncogenomic investigations can include rs10008492, rs4833103, rs5743815, rs11466657, rs7696175 (TLR1-TLR6-TLR10 gene cluster); rs3804100, rs4696480, -196 - -174 del (Delta22), GT-microsatellite polymorphism (TLR2); 829A/C (TLR3); rs5743836, rs352140 (TLR9). The extended list can additionally include rs4833095 rs5743551, rs5743618 (TLR1); rs5743704, rs62323857, rs1219178642 (TLR2); rs5743305, rs3775291, rs121434431, rs5743316 (TLR3); rs5744168 (TLR5); rs179008 (TLR7); rs3764880, rs2407992 (TLR8); rs352139, rs187084, rs41308230, rs5743844 (TLR9); rs4129009 (TLR10). General reasons for discrepancies between studies are insufficiency of sample size, age/gender/BMI/ethnic/racial differences, differences in prevalence of infectious agent in case and control groups, differences in immune response caused by specific ligand, differences in stratification, methods of diagnostics of cancer or chronic inflammatory conditions, genotyping methods, and chance. Future well-designed studies on large samples should shed light on the significance of TLR polymorphisms for cancer prevention.     

Relation of elastosis to biochemical and immunohistochemical steroid receptor findings,Ki-67 and epidermal growth factor receptor (EGFR) immunostaining in invasive ductal breast cancer

We studied 1073 cases of invasive ductal breast cancer, NOS for their elastic content (DEL, ductal + periductal elastosis; TEL, tumour elastosis) and compared the findings with the results of biochemical and immunohistochemical steroid hormone receptor examination. Tumours of patients up to 50 years of age and older were examined separately. In a number of tumours elastosis was also examined in relation to Ki-67 and epidermal growth factor receptor (EGFR) immunostaining. Sensitivity and specificity of DEL and TEL for predicting the receptor, Ki-67 and EGFR findings were estimated. Sensitivity of DEL and TEL for oestrogen and progesterone receptors is dependent on the degree of tumour differentiation and the degree of elastosis, increasing from DEL 1° and TEL 1° to DEL 3° and TEL 3°. It was more evident in grade 1 (G1) and G2 than in G3 carcinomas. Elastosis is a useful predictor of positive receptor findings particularly in G1 and G2 tumours with moderate and high-grade elastosis. It is a similarly useful predictor of negative receptor values in G3 carcinomas. The predictive value of DEL and TEL for the results of Ki-67 and EGFR immunostaining gradually decreases with increasing elastosis, consistent with the assumption that Ki-67 and EGFR identify the degree of tumour proliferation and invasion, while elastosis correlates with the degree of differentiation of breast cancer. Elastosis is a poor predictor of Ki-67 and EGFR findings in any individual breast cancer. Moderate and high-grade elastosis points to positive steroid hormone receptor assays in G1 and G2 carcinomas. In contrast, the lack of elastosis in G3 carcinomas may indicate a negative receptor assay. Both findings have a high degree of reliability.     

免疫途径及载体对乙肝病毒DNA疫苗免疫效果影响的研究

目的探讨ＤＮＡ载体结构及接种途径对ＤＮＡ疫苗免疫效果的影响。方法分别构建插入ＨＢＶ表面抗原编码基因的表达载体ｐｃＤＮＡ１．１／ＳＡ（无抗性基因）和ｐｃＤＮＡＩ／Ａｍｐ／ＳＡ（含氨苄青霉素抗性基因）,肌注小鼠后比较其诱生特异性免疫应答的能力;同时比较不同接种途径（肌内、皮内、皮肤划痕）及ＣｐＧ免疫刺激元件（ＩＳＳ）对ＤＮＡ疫苗诱生免疫效果的影响。结果ｐｃＤＮＡＩ／Ａｍｐ／ＳＡ的免疫效果优于ｐｃＤＮＡ１．１／ＳＡ。ｐｃＤＮＡ１．１／ＳＡ的免疫效果可被ＩＳＳ增强,而ｐｃＤＮＡＩ／Ａｍｐ／ＳＡ诱生特异性免疫应答的能力则可被ＩＳＳ抑制;诱生免疫应答的能力以肌内注射最强,皮内注射免疫其次,皮下划痕法较弱。结论不同ＨＢｓＡｇ表达载体诱生免疫应答的能力不尽相同;ＣｐＧ免疫刺激元件在决定ＤＮＡ疫苗免疫原性中起重要作用,可增强不含相应结构ＤＮＡ疫苗的免疫效果;皮内注射可诱发与肌内接种相似的免疫应答,是一种简便、有效的免疫接种途径     

Cell mediated immune response of the Mediterranean sea urchin Paracentrotus lividus after PAMPs stimulation

The Mediterranean sea urchin (Paracentrotus lividus) is of great ecological and economic importance for the European aquaculture. Yet, most of the studies regarding echinoderm's immunological defense mechanisms reported so far have used the sea urchin Strongylocentrotus purpuratus as a model, and information on the immunological defense mechanisms of Paracentrotus lividus and other sea urchins, is scarce. To remedy this gap in information, in this study, flow cytometry was used to evaluate several cellular immune mechanisms, such as phagocytosis, cell cooperation, and ROS production in P. lividus coelomocytes after PAMP stimulation. Two cell populations were described. Of the two, the amoeboid-phagocytes were responsible for the phagocytosis and ROS production. Cooperation between amoeboid-phagocytes and non-adherent cells resulted in an increased phagocytic response. Stimulation with several PAMPs modified the phagocytic activity and the production of ROS. The premise that the coelomocytes were activated by the bacterial components was confirmed by the expression levels of two cell mediated immune genes: LPS-Induced TNF-alpha Factor (LITAF) and macrophage migration inhibitory factor (MIF). These results have helped us understand the cellular immune mechanisms in P. lividus and their modulation after PAMP stimulation.     

Signal pathway involved in inhibition by lipoxin A4 of production of interleukins induced in endothelial cells by lipopolysaccharide

Objective and design:  We examine whether lipoxin A₄4 (LXA₄) inhibits production of interleukins (ILs) in endothelial cells and what signal pathway might participate in the actions of LXA₄. Methods:  Cultured pulmonary microvascular endothelial cells (PMVEC) were treated with lipopolysaccharide (LPS), with or without preincubation with LXA₄. Results:  The results showed that LPS induced production of IL-1β, IL-6 and IL-8 in rat PMVEC, upregulated the expressions of myeloid differentiation factor 88 (MyD88), phosphorylated p38 and p42/44 mitogen-activated protein kinase (MAPK), phosphorylated phosphoinositide 3-kinase (PI3-K), DNA-binding activities of nuclear factor-κ B (NF-κB) and activator protein-1(AP-1). The blockade of p38 MAPK, p42/44 MAPK, PI3-K, NF-κB or AP-1 partially inhibited production of IL-1β, IL-6 and IL-8 stimulated by LPS, respectively. LXA₄ significantly inhibited LPS-stimulated secretion of protein and expressions of mRNA of IL-1β, IL-6 and IL-8, activation of p38 MAPK, p42/44 MAPK, PI3-K, NF-κB and AP-1 but not MyD88 in PMVEC. Conclusions:  LXA₄ inhibits synthesis of IL-1β, IL-6 and IL-8 in PMVEC and this antagonism is related to PI3-K, p38 and p42/44 MAPK, NF-κB and AP-1 pathway-dependent signal transduction. Received 7 August 2007; returned for revision 21 December 2007; received from final revision 17 February 2008; accepted by M. Katori 11 March 2008     

Biphasic control of nuclear factor-χB activation by the T cell receptor complex: role of tumor necrosis factor α

The regulation of nuclear factor (NF)-χB activation by the T cell receptor (TcR)/CD3 complex in primary human T cells has been studied at various times after activation. Only p50 NF-χB protein bound the χB element of interleukin-2 receptor (IL-2R) α chain promoter on resting T cells. However, immediately after TcR/CD3 cross-linking (after approximately 1 h; immediate) binding of p50.p65 heterodimers was observed. p50.c-rel heterodimers were also detected bound to this sequence at early time points (7–16 h; early), and both remained active at later time points (40 h; late) after activation. This regulation takes place mainly at the level of nuclear translocation of p65 and c-rel, at immediate and early time points. Activation also induced c-rel and p105/p50 mRNA synthesis, but not p65 mRNA whose expression was constitutive. Interestingly, all those early and late events, but not the immediate ones, were inhibited by a neutralizing anti-tumor necrosis factor α (TNF-α) monoclonal antibody. Similarly, cycloheximide prevented the p65 and c-rel translocation and consequent formation of active binding heterodimers, at early and late times. Cyclosporin A impaired not only early and late, but also immediate events; however, addition of TNF-α prevented all inhibition. These results indicate that the regulation of NF-χB activation during T cell activation by TcR/CD3 signals is biphasic: TcR/CD3 triggers its immediate translocation, which is transient if no TNF-α is present. TNF-α, therefore, emerges as the main factor responsible for a second phase of NF-χB regulation, controlling both translocation of p65 and c-rel, and new mRNA synthesis for c-rel and p105/p50.