Alteration of iron regulatory proteins (IRP1 and IRP2) and ferritin in the brains of scrapie-infected mice

Considerable evidence suggests that oxidative stress may be involved in the pathogenesis of Transmissible Spongiform Encephalopathies (TSEs). To investigate the involvement of iron metabolism in TSEs, we examined the expression levels of iron regulatory proteins (IRPs), ferritins, and binding activities of IRPs to iron-responsive element (IRE) in scrapie-infected mice. We found that the IRPs-IRE-binding activities and ferritins were increased in the astrocytes of hippocampus and cerebral cortex in the brains of scrapie-infected mice. These results suggest that alteration of iron metabolism contributes to development of neurodegeneration and that some protective mechanisms against iron-induced oxidative damage may occur during the pathogenesis of TSEs.     

Athletic induced iron deficiency: new insights into the role of inflammation, cytokines and hormones

Iron is utilised by the body for oxygen transport and energy production, and is therefore essential to athletic performance. Commonly, athletes are diagnosed as iron deficient, however, contrasting evidence exists as to the severity of deficiency and the effect on performance. Iron losses can result from a host of mechanisms during exercise such as hemolysis, hematuria, sweating and gastrointestinal bleeding. Additionally, recent research investigating the anemia of inflammation during states of chronic disease has allowed us to draw some comparisons between unhealthy populations and athletes. The acute-phase response is a well-recognised reaction to both exercise and disease. Elevated cytokine levels from such a response have been shown to increase the liver production of the hormone Hepcidin. Hepcidin up-regulation has a negative impact on the iron transport and absorption channels within the body, and may explain a potential new mechanism behind iron deficiency in athletes. This review will attempt to explore the current literature that exits in this new area of iron metabolism and exercise.     

沉默信息调节因子2相关酶1在炎症反应中的调节机制研究进展

沉默信息调节因子相关酶1(SIRT1)是酵母沉默信息调节因子2(Sir2)的哺乳动物同源体,是一种高度保守的NAD+依赖的组蛋白去乙酰化酶.SIRT1的作用底物众多,不仅可以对组蛋白进行去乙酰化作用,还可与多种转录因子和信号分子相互作用.SIRT1的去乙酰化酶活性影响细胞的存活、分化、衰老和凋亡,因而现在已成为生命科学研究的热点.最近几年发现其在炎症反应的发生发展中也发挥着重要调节作用.     

Changes in the morphology and phosphatase cytochemistry of the Golgi region of hepatocytes during the acute phase response to inflammation

Background: During the acute phase response to inflammation, the Golgi apparatus of rat hepatocytes processes an increased quantity of glycoproteins, in the form of acute phase reactants. Methods: The compartmental organization of the hepatocyte Golgi of control and 24 hour inflamed rats was studied, using transmission electron microscopic techniques, including cytochemistry, to detect nicotinamide adenine dinucleotide phosphatase (NADPase), thiamine pyrophosphatase (TPPase), and cytidine monophosphatase (CMPase) activity. Results: In inflamed rats, individual Golgi stacks were enlarged, but retained their organization into four compartments:1) a phosphatase negative, perforated cis-element, 2) two mid-saccules which sometimes were positive for NADPase, 3) one or occasionally two NADPase and TPPase positive trans-saccules, and 4) a tubulovesicular trans-Golgi network (TGN) which was NADPase reactive and contained a spotty TPPase reaction product. Two of these compartments were noticably altered in response to inflammation. The two mid-saccules were consistently and uniformly dilated. The TGN was altered to the point of being difficult to recognize and had acquired CMPase reactivity. In control rats the TGN consisted of anastomosing tubules forming cage-like structures; secretory granules containing lipoprotein particles pinched off from these. In inflamed rats, most of the cage-like TGN structures had been replaced with an extensive vesicular syncytium which produced secretory granules with a granulofilamentous content. Conclusions: In hepatocytes from inflamed rats an apparent switch had occured in the type of secretory material processed by the Golgi apparatus. Furthermore, the inflammation-induced increase in the size of individual Golgi stacks apparently was not due to a parallel increase in size of all Golgi saccules. Rather, saccules within given Golgi compartments responded in a characteristic and specific manner to the increase in glycoprotein processing that occurs during inflammation. © 1995 Wiley-Liss, Inc.     

Abnormal body iron distribution and erythropoiesis in a novel mouse model with inducible gain of iron regulatory protein (IRP)-1 function

Disorders of iron metabolism account for some of the most common human diseases. Cellular iron homeostasis is maintained by iron regulatory proteins (IRP)-1 and 2 through their binding to cis-regulatory iron-responsive elements (IREs) in target mRNAs. Mouse models with IRP deficiency have yielded valuable insights into iron biology, but the physiological consequences of gain of IRP function in mammalian organisms have remained unexplored. Here, we report the generation of a mouse line allowing conditional expression of a constitutively active IRP1 mutant (IRP1*) using Cre/Lox technology. Systemic activation of the IRP1* transgene from the Rosa26 locus yields viable animals with gain of IRE-binding activity in all the organs analyzed. IRP1* activation alters the expression of IRP target genes and is accompanied by iron loading in the same organs. Furthermore, mice display macrocytic erythropenia with decreased hematocrit and hemoglobin levels as well as impaired erythroid differentiation. Thus, inappropriately high IRP1 activity causes disturbed body iron distribution and erythropoiesis. This new mouse model further highlights the importance of appropriate IRP regulation in central organs of iron metabolism. Moreover, it opens novel avenues to study diseases associated with abnormally high IRP1 activity, such as Parkinson’s disease or Friedreich’s ataxia.     

Interleukin-6 and selected plasma proteins in healthy persons of different ages

In the present study, interleukin-6(IL-6) and several acute phase proteins were measured in healthy participants (23–87 years of age). A linear correlation between IL-6 and age was established with an increase of 0.016 pg/ml(00.004) per year of life. Whereas CRP remained below 0.5 mg/dl in all participants, an increase with age for fibrinogen and an inverse relation for albumin as well as transferrin were obtained. However, the increase of IL-6 did not correlate with any of these changes. IL-6 associated diseases may therefore occur more often with advancing age, but in healthy participants IL-6 does not explain the changing plasma protein pattern resembling that of an acute phase reaction.     

Antibodies against acute phase proteins and their functions in the pathogenesis of disease: a collective profile of 25 different antibodies

The acute phase response is a defense system in which the innate immune response is activated following injury or infection. Positive and negative acute phase proteins (APPs) are crucial for protecting the host organism, as well as returning it to homeostatic levels, the first with elevated concentrations and the latter with decreased concentrations during the acute phase. Reports about the presence of antibodies against APPs are known, however their individual, as well as potentially collective, pathological or physiological roles are still emerging. Some of these autoantibodies are specifically connected with diseases (such as pancreatic secretory trypsin inhibitor and C3, C4 nephritic factors), while others have been reported as natural antibodies. The persistent presence (even if only minor) of autoantibodies in healthy blood donors indicates an overlapping category of autoantibodies, which could become pathogenic, depending on the autoantibody characteristics such as avidity, epitope specificity, changes in the microenvironment leading to different oxidative status and others. This review uses the novel approach of studying the overall autoantibody population against APPs, their functions and connections to diseases. The primary function of autoantibodies against APPs (anti-APPs) is thought to promote their clearance, however autoantibodies against negative APPs have also been found and applying the same role to those is doubtful. There is also the theory of consumption in the stage of inflammation, which could be relevant to anti-APPs. Reports about protective roles of autoantibodies are also emerging, showing lowered levels of antibodies in diseases, which could be interesting for therapeutic intervention.     

In vitro and in vivo inhibitory effects of 6-hydroxyrubiadin on lipopolysaccharide-induced inflammation

Inflammation is a defensive response against a multitude of harmful stimuli and stress conditions such as tissue injury, and is one of the most common pathological processes of human diseases. 6-Hydroxyrubiadin, an anthraquinone isolated from Rubia cordifolia L., exhibits several bioactive properties. The aim of this study was to evaluate whether 6-hydroxyrubiadin can reduce the production of pro-inflammatory cytokines and ameliorate acute lung injury (ALI) in a mouse model. In this study, we demonstrated that 6-hydroxyrubiadin suppressed lipopolysaccharide (LPS)-induced nuclear factor-kappa B activation as well as the phosphorylation of c-Jun N-terminal kinase in RAW 264.7 macrophages. In addition, we also showed that 6-hydroxyrubiadin inhibited the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in phorbol myristate acetate (PMA)-primed U937 and RAW 264.7 cells. Furthermore, 6-hydroxyrubiadin treatment reduced the production of these cytokines in vivo and attenuated the severity of LPS-induced ALI. Thus, these results suggested that 6-hydroxyrubiadin may be a potential therapeutic candidate for the treatment of inflammation and inflammatory diseases.     

Thy-1 (CD90) regulates the extravasation of leukocytes during inflammation

Human Thy-1 (CD90) has been shown to mediate adhesion of inflammatory cells to activated microvascular endothelial cells via interaction with Mac-1 (CD11b/CD18) in vitro. Since there are no data showing the physiological relevance of Thy-1 for the recruitment of inflammatory cells in vivo, different inflammation models were investigated in Thy-1-deficient mice and littermate controls. In thioglycollate-induced peritonitis, the number of neutrophils and monocytes was significantly diminished in Thy-1-deficient mice. During acute lung inflammation, the extravasation of eosinophils and monocytes into the lung was significantly reduced in Thy-1-deficient mice. Moreover, during chronic lung inflammation, the influx of eosinophils and monocytes was also strongly decreased. These effects were independent of Thy-1 expression on T cells, as shown by the transplantation of WT BM into the Thy-1-deficient mice. In spite of the strong Thy-1 expression on T cells in the chimeric mice, the extravasation of the inflammatory cells in these mice was significantly diminished, compared to control mice. Finally, the altered number and composition of infiltrating leukocytes in Thy-1-deficient mice modified the chemokine/cytokine and protease expression at the site of inflammation. In conclusion, Thy-1 is involved in the control of inflammatory cell recruitment and, thus, also in conditioning the inflammatory microenvironment.     

A regulatory role for suppressor of cytokine signaling-1 in T(h) polarization in vivo

Suppressor of cytokine signaling (SOCS)-1 is an inhibitory molecule for JAK, and its deficiency in mice leads to lymphocyte-dependent multi-organ disease and perinatal death. Crossing of SOCS-1(-/-) mice on an IFN-gamma(-/-), STAT1(-/-) and STAT6(-/-) background revealed that the fatal disease of SOCS-1(-/-) mice is also dependent on IFN-gamma/STAT1 and IL-4/STAT6 signaling pathways. Since IFN-gamma and IL-4 are representative T(h)1 and T(h)2 cytokines respectively, here we investigated the role of SOCS-1 in T(h) differentiation. Freshly isolated SOCS-1(-/-) CD4(+) T cells stimulated with anti-CD3 rapidly produced larger amounts of IFN-gamma and IL-4 than control cells, suggesting that these mutant T cells had already differentiated into T(h)1 and T(h)2 cells in vivo. In addition, SOCS-1(+/-) CD4(+) T cells cultured in vitro produced significantly larger amounts of IFN-gamma and IL-4 than SOCS-1(+/+) cells. Similarly, SOCS-1(+/-) CD4(+) T cells produced more IFN-gamma and IL-4 than SOCS-1(+/+) cells after infection with Listeria monocytogenes and Nippostrongyrus braziliensis respectively. Since IL-12-induced STAT4 and IL-4-induced STAT6 activation is sustained in SOCS-1(-/-) T cells, the enhanced T(h) functions in SOCS-1(-/-) and SOCS-1(+/-) mice appear to be due to the enhanced effects of these cytokines. These results suggest that SOCS-1 plays a regulatory role in both T(h)1 and T(h)2 polarizations.     

参与免疫及炎症反应调控的胞浆蛋白NODs

Nucleotide- binding oligomerization domain (NOD) proteins are members of a growing family of cytosolic factors related to the apoptosis regulator Apaf-1 and a class of plant disease resistance proteins. NOD proteins have been implicated in the induction of NF-κB activity and in the activation of caspases. Biochemical evidence has unraveled the role of NOD1 and NOD2 as intraceUular sensors of bacterial peptidoglycan. Notably, genetic variation in the genes encoding the NOD proteins NOD2, cryopyrin and C Ⅱ TA inhmnans is associated with inflammatory disease or increased susceptibility to bacterial infections. NOD proteins may be involved in the recognition of microorganisms and regulation of inflammatory responses.     

Acute phase proteins and IP-10 as triage tests for the diagnosis of tuberculosis: systematic review and meta-analysis

Objectives

We examined the data reported in studies for diagnostic purposes and to discuss whether their intended use could be extended to triage, as rule-in or rule-out tests to select individuals who should undergo further confirmatory tests.

The DNA-binding subunit p140 of replication factor C is upregulated in cycling cells and associates with G1 phase cell cycle regulatory proteins

The DNA-binding subunit of replication factor C (RFCp140) plays an important role in both DNA replication and DNA repair. The mechanisms regulating activation of RFCp140 thereby controlling replication and cellular proliferation are largely unknown. We analyzed protein expression of RFCp140 during cell cycle progression and investigated the association of RFCp140 with cell cycle regulatory proteins in cell lines of various tissue origin and in primary hematopoietic cells. Western and Northern blot analyses of RFCp140 from synchronized cells showed downregulation of RFCp140 when cells enter a G₀-like quiescent state and upregulation of RFCp140 in cycling cells. Translocation from the cytoplasmic compartment to the nucleus did not account for the significant increase in RFCp140 protein levels observed in cycling cells. To investigate a potential association of RFCp140 with cell cycle regulatory proteins coimmunoprecipitation assays were performed. These studies demonstrated specific binding of RFCp140 to cdk4-kinase in hematopoietic and fibroblast cell lines. Additional coimmunoprecipitation studies revealed specific association of RFCp140 with cyclin D1, p21, proliferating cell nuclear antigen, and retinoblastoma protein. These findings link DNA replication and repair factor RFCp140 to G₁ phase cell cycle regulatory elements critically involved in cell cycle control. Received: 13 May 1998 / Accepted: 1 February 1999     

High levels of p105 (NFKB1) and p100 (NFKB2) proteins in HPV16-transformed keratinocytes: role of E6 and E7 oncoproteins

We have previously shown that functional components of the NF-kappaB signaling pathway are up-regulated and sequestered in the cytoplasm of human papillomavirus 16 (HPV16)-transformed cell lines leading to a reduced activity of NF-kappaB. In this study, we examined the expression of the NF-kappaB precursors p100 and p105 in keratinocytes transformed or not by HPV16. Western immunoblotting experiments demonstrated high levels of p100 and p105 proteins not only in HPV16+ cervical carcinoma-derived keratinocytes but also in keratinocytes stably transfected by HPV16 E6 or E7 oncogenes. Moreover, p100 and p105 proteins were predominantly cytoplasmic and nuclear in keratinocytes expressing E7 and E6, respectively. A predominantly cytoplasmic localization of E7 protein was also detected in all keratinocytes expressing E7. Our results suggest that HPV16 E6 and E7 proteins modulate the expression and the subcellular localization of p100 and p105 NF-kappaB precursors.     

Changes in markers of muscle damage, inflammation and HSP70 after an Ironman triathlon race

We investigated the effects of an Ironman triathlon race on markers of muscle damage, inflammation and heat shock protein 70 (HSP70). Nine well-trained male triathletes (mean ± SD age 34 ± 5 years; V̇O_2peak 66.4 ml kg⁻¹ min⁻¹) participated in the 2004 Western Australia Ironman triathlon race (3.8 km swim, 180 km cycle, 42.2 km run). We assessed jump height, muscle strength and soreness, and collected venous blood samples 2 days before the race, within 30 min and 14–20 h after the race. Plasma samples were analysed for muscle proteins, acute phase proteins, cytokines, heat shock protein 70 (HSP70), and clinical biochemical variables related to dehydration, haemolysis, liver and renal functions. Muscular strength and jump height decreased significantly (P < 0.05) after the race, whereas muscle soreness and the plasma concentrations of muscle proteins increased. The cytokines interleukin (IL)-1 receptor antagonist, IL-6 and IL-10, and HSP70 increased markedly after the race, while IL-12p40 and granulocyte colony-stimulating factor (G-CSF) were also elevated. IL-4, IL-1β and tumour necrosis factor-α did not change significantly, despite elevated C-reactive protein and serum amyloid protein A on the day after the race. Plasma creatinine, uric acid and total bilirubin concentrations and γ-glutamyl transferase activity also changed after the race. In conclusion, despite evidence of muscle damage and an acute phase response after the race, the pro-inflammatory cytokine response was minimal and anti-inflammatory cytokines were induced. HSP70 is released into the circulation as a function of exercise duration.     

Dock2 in the development of inflammation and cancer

An atypical guanine exchange factor, Dock2 is specifically expressed in hematopoietic cells and regulates activation and migration of immune cells through activating Ras‐related C3 botulinum toxin substrate (Rac). Dock2 was shown to be critical in the development of various inflammatory diseases, including allergic diseases, HIV infection, and graft rejection in organ transplantation. DOCK2 mutation in infants was recently identified to be associated with T and B cell combined immunodeficiency. Furthermore, Dock2 is involved in host protection during enteric bacterial infection and is also associated with the proliferation of cancer cells. It was also shown that patients with digestive tract cancer had high frequency mutation of DOCK2. This review summarizes the latest research progresses on the role of Dock2 for the development of various inflammatory diseases and cancers, and discusses the potential application of Dock2 modulators for patient treatment.     

Pig-MAP, porcine acute phase proteins and standardisation of assays in Europe

The pattern of plasma proteins changes greatly following infection, inflammation or tissue injury. The concentration of some proteins referred to as acute phase proteins (APPs) significantly increases within hours or days after the onset of these processes. In contrast, the concentration of other proteins, such as albumin (Alb), called negative acute phase proteins, decreases. APPs have been extensively studied in man and rat, but less so in other species. In recent work, the APPs have been characterised in pigs in response to inflammation following turpentine injection. The concentrations of C reactive protein (CRP) and haptoglobin (Hp) increase 5–7 times 48 h after the injection. Porcine Alb, α-lipoprotein, fetuin and transferrin were negative APP. Finally, the concentration of α₁-acid glycoprotein and α₁-protease inhibitor (α₁-antitrypsin) did not change significantly during the inflammation. In addition to CRP and Hp, a serum α₂-globulin was observed to be the major acute phase (MAP) protein in pigs. Pig-MAP is a new mammalian plasma protein, which is the pig counterpart of a recently cloned human serum protein denominated PK-120 or IHRP. Pig-MAP shows promise as a prominent positive APP and has been shown to be a good marker of different pig pathologies. Recent collaboration in an EU-Concerted Action Project (AIR3-CT94-2255) has joined several laboratories involved in pig APP studies in Europe. These groups have been working on the approach that APP are markers for the presence of infectious, inflammatory and pathological lesions in animals. The ability to monitor the APP concentration in serum of pigs will improve the quality and safety of the meat produced as well as provide important diagnostic information for animal health and welfare. The serum concentration of APP are altered in several diseases supporting that APP can be used as markers of pig pathologies. Antibody-based techniques (for example, ELISA and immunonephelometric assays) have been and will be further developed for the selected porcine APP to accomplish these objectives. However, an important effort should be made in the future between laboratories and between countries in Europe to standardise assays for porcine proteins and to harmonise the different methods currently used for measuring the porcine APPs. Originally presented at the Third European Conference on Comparative Clinical Pathology, Breda.     

Changes in Lp(a) lipoprotein and other plasma proteins during acute myocardial infarction

The sequential changes of Lp(a) lipoprotein concentrations in patients (n=59) suffering acute myocardial infarction (AMI) were examined and compared with other plasma proteins. The temporal and quantitative characteristics of the responses in concentration of acute phase reactants (CRP, haptoglobin, α₁-antitrypsin, α-acid glycoprotein), lipids (total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol) and apolipoproteins AI and B were similar to previous reports. Lp(a) lipoprotein showed transient changes with an initial decrease of 10–25% compared to the 3-month control value, followed by rebound on day 7–11 above admission level, before again declining. We were able to demonstrate a quantitative relationship between infarct size and alterations in plasma levels of acute phase reactants. However, in addition to rather unusual significant fluctuations during AMI, Lp(a) lipoprotein changes seemed unrelated to infarct size. These findings do not support the view that Lp(a) lipoprotein acts as an acute phase reactant.     

Expression of cell cycle regulatory proteins in the multistep process of oesophageal carcinogenesis: stepwise over-expression of cyclin E and p53, reduction of p21(WAF1/CIP1) and dysregulation of cyclin D1 and p27(KIP1)

AIMS: Cell cycle regulatory proteins were analysed by immunohistochemistry in order to clarify how their expression changes with the degree of atypia as oesophageal surface squamous epithelium progresses from normal mucosa, through reactive change, low-grade dysplasia, and high-grade dysplasia to mucosal invasive carcinoma. METHODS AND RESULTS: Immunostaining for cyclin D1, cyclin E, p21, p27, p53 and Ki67 proteins was performed using 22 normal mucosa, 17 reactive change, 22 low-grade dysplasia, 15 high-grade dysplasia and 22 mucosal invasive carcinoma specimens. Normal mucosa, low-grade dysplasia and high-grade dysplasia samples were taken from patients without any oesophageal invasive carcinoma by endoscopic biopsy or endoscopic mucosal resection, and reactive change and mucosal invasive carcinoma were obtained from oesophagectomy material. Stepwise over-expression of cyclin E (P < 0.0001) and p53 (P < 0.0001), reduction of p21 (P=0.0189) and dysregulation of cyclin D1 and p27 were observed in the multistep process of oesophageal carcinogenesis. Significant differences in expression of p27 (P < 0.0001), p53 (P=0.0299) and Ki67 (P=0.0101) were observed between reactive change and low-grade dysplasia. Furthermore, expression of cyclin D1, cyclin E, p27 and p53 in mucosal invasive carcinoma were significantly different from those in high-grade dysplasia (P=0.0079, P=0.0237, P=0.0042 and P= 0.0299, respectively). CONCLUSIONS: Cell cycle regulatory proteins, cyclin E, p53 and p21 show stepwise over-expression or reduction with progression of oesophageal carcinogenesis, correlating with the increased cell proliferation observed with Ki67 labelling. We conclude that immunohistochemical analysis for p27, p53 and Ki67 is practically useful for the discrimination between low-grade dysplasia and reactive change. Cyclin D1, cyclin E, p27 and p53 help to distinguish high-grade dysplasia from mucosal invasive carcinoma.