Effect of Acute and Prolonged Inflammation on the Gene Expression of Proinflammatory Cytokines and Their Receptors in the Anterior Pituitary Gland of Ewes

An acute and prolonged inflammation inhibits the reproduction process by the disruption of the neurohormonal activity of the hypothalamic-pituitary-gonadal axis. It is thought that these changes may be caused by proinflammatory cytokines, i.e., interleukin (IL) -1β, IL-6 and tumor necrosis factor (TNF) α. The aim of this study was to determine the effect of an acute and prolonged inflammation on the expression of genes encoding cytokine and their receptors, gonadotropin releasing hormone receptor (GnRHR), beta subunits of luteinizing hormone (LHβ) and follicle-stimulating (FSHβ) in the anterior pituitary (AP). Moreover, the circulating concentration of LH and FSH was also assayed. Two experiments were carried out on adult ewes which were divided into two control groups and treated with lipopolysaccharide (LPS; 400 ng / kg). Acute inflammation was caused by a single injection of LPS into the external jugular vein, while the chronic inflammation was induced by seven times LPS injection (one a day). In both experiments, animals were euthanized 3h after the last LPS / NaCl injection and the blood samples collected 15 min before euthanasia. An acute inflammation stimulates the expression of the IL-1β, IL-6 and TNFα genes and their receptors in the AP of sheep. Prolonged inflammation increased TNFα gene expression and both types of TNFα and IL-6 receptors. Both an acute and prolonged inflammation inhibited LHβ gene expression in the AP and reduced LH level in blood. A sevenfold LPS injection raises FSH concentration. The gene expression of GnRHR was reduced in the ovine AP only after a single injection of endotoxin. Our results suggest that there are important differences in the way how an acute and prolonged inflammation influence proinflammatory cytokines and their receptors gene expression in the AP of anestrous ewes, which could be reflected by differences in the AP secretory activity during these states.

Pituitary adenylate cyclase-activating polypeptide (PACAP-38) plays an inhibitory role against inflammation induced by chemical damage to zebrafish hair cells

Pituitary adenylate cyclase-activating polypeptide (PACAP-38) is a common neuropeptide exerting a wide spectrum of functions in many fields, including immunology. In the present study, 5-day post-fertilization (dpf) zebrafish larvae of three diverse genetic lines [transgenic lines Tg(MPX:GFP) with GFP-labelled neutrophils and Tg(pou4f3:GAP-GFP) with GFP-labelled hair cells and the wild-type Tuebingen] were used to investigate an inhibitory role of PACAP-38 in inflammation associated with damaged hair cells of the lateral line. Individuals of each genetic line were assigned to four groups: (1) control, and those consisting of larvae exposed to (2) 10 µM CuSO4, (3) 10 µM CuSO4+100 nM PACAP-38 and (4) 100 nM PACAP-38, respectively. Forty-minute exposure to CuSO4 solution was applied to evoke necrosis of hair cells and consequent inflammation. The inhibitory role of PACAP-38 was investigated in vivo under a confocal microscope by counting neutrophils migrating towards damaged hair cells in Tg(MPX:GFP) larvae. In CuSO4-treated individuals, the number of neutrophils associated with hair cells was dramatically increased, while PACAP-38 co-treatment resulted in its over 2-fold decrease. However, co-treatment with PACAP-38 did not prevent hair cells from extensive necrosis, which was found in Tg(pou4f3:GAP-GFP) individuals. Real-Time PCR analysis performed in wild-type larvae demonstrated differential expression pattern of stress and inflammation inducible markers. The most significant findings showed that CuSO4 exposure up-regulated the expression of IL-8, IL-1β, IL-6 and ATF3, while after PACAP-38 co-treatment expression levels of these genes were significantly decreased. The presence of transcripts for all PACAP receptors in neutrophils was also revealed. Adcyap1r1a and vipr1b appeared to be predominant forms. The present results suggest that PACAP-38 should be considered as a factor playing an important regulatory role in inflammatory response associated with pathological processes affecting zebrafish hair cells and it cannot be excluded that this interesting property has more universal significance.

Differential Requirements for IL-17A and IL-22 in Cecal versus Colonic Inflammation Induced by Helicobacter hepaticus

Type 17 helper T-cell cytokines have been implicated in the pathogenesis of inflammatory bowel disease, a chronic condition affecting the gastrointestinal tract, but information regarding their contribution to pathology in different regions of the gut is lacking. By using a murine model of bacteria-induced typhlocolitis, we investigated the role of IL-17A, IL-17F, and IL-22 in cecal versus colonic inflammation. Cecal, but not colonic, pathology in C57BL/6 mice inoculated with Helicobacter hepaticus plus anti-IL-10 receptor (IL-10R) monoclonal antibody was exacerbated by co-administration of anti-IL-17A monoclonal antibody, suggesting a disease-protective role for IL-17A in the cecum. In contrast, anti-IL-17F had no effect on H. hepaticus-induced intestinal pathology. Neutralization of IL-22 prevented the development of colonic, but not cecal, inflammation in H. hepaticus-infected anti-IL-10R-treated mice, demonstrating a pathogenic role for IL-22 in the colon. Analysis of transcript levels revealed differential expression of IL-22R, IL-22 binding protein, and IL-23R between cecum and colon, a finding that may help explain why these tissues respond differently after anti-IL-22 treatment. Analysis of microarray data from healthy human intestine further revealed significant differences in cytokine receptor transcript levels (including IL-22RA1 and IL-23R) in distinct parts of the human gut. Together, our findings demonstrate that individual type 17 helper T-cell cytokines can have proinflammatory or anti-inflammatory effects in different regions of the intestine, an observation that may have implications for interventions against human inflammatory bowel disease.

A Potential Mechanism of High-Dose Ticagrelor in Modulating Platelet Activity and Atherosclerosis Mediated by Thymic Stromal Lymphopoietin Receptor

Abnormal expression of thymic stromal lymphopoietin (TSLP) and its receptor (TSLPR) was found in patients with acute coronary syndrome. Ticagrelor, an oral platelet ADP P2Y12 receptor antagonist, is widely used in these patients. The aim of this study was to verify whether different doses of ticagrelor regulated plaque progression and platelet activity by modulating TSLP/TSLPR. Seventy-five ApoE-/- mice were randomly divided into five groups: (1) high-cholesterol diet (HCD, n = 15); (2) HCD plus ticagrelor 25 mg/kg/d (T1, n = 15); (3) HCD plus ticagrelor 50 mg/kg/d (T2, n = 15); (4) HCD plus ticagrelor 100 mg/kg/d (T3, n = 15); and (5) a normal diet group (ND, n = 15). At day 0 and at week 16, blood lipids and serum TSLP levels, expression of TSLPR, CD62, and CD63, platelet aggregation, platelet ATP release, PI3K/Akt signaling pathway, and plaque morphology were assessed. HCD increased TSLPR expression and atherosclerosis progression but high-dose ticagrelor (100 mg/kg) moderated this trend. TSLPR was positively correlated with Akt1, platelet aggregation, corrected plaque area, and vulnerability index in the T3 group (P<0.01). In conclusion, low-dose ticagrelor only inhibited platelet activity. Besides this inhibition, high-dose ticagrelor modulated platelet activity and atherosclerosis mediated by TSLPR, potentially through the PI3K/Akt signal pathway.

Molecular characterisation of four class 2 cytokine receptor family members in rainbow trout, Oncorhynchus mykiss

The interleukin (IL)-10 cytokine family includes IL-10, IL-19, IL-20, IL-22, IL-24, IL-26 and the lambda/type III interferons. They are highly pleiotropic and mediate a variety of activities, including immune suppression and antibacterial immunity. To exert their functions they signal through a heterodimeric receptor composed of a subunit with a long intracellular domain (R1 type receptors; IL-10R1, IL-20R1 or IL-22R1) and a subunit with a short intracellular domain (R2 type receptors; IL-10R2 or IL-20R2). In this study we report the identification of three R1 type receptors (named IL-10R1/CRFB7, IL-20R1a/CRFB8a and IL-20R1b/CRFB8b) and one R2 type receptor (named IL-10R2/CRFB4) in rainbow trout. The nomenclature of the receptors was supported by homology analysis, conserved motifs and phylogenetic tree analysis, confirming they belong to the piscine class 2 cytokine receptor family. For instance, they all displayed the presence of characteristic features, such as conserved fibronectin type-III domains. Expression analysis in tissues collected from healthy fish revealed different patterns of expression for each receptor, suggesting their potential involvement in different types of immune responses. When studying the modulation of the genes in cell lines and primary cultures, a greater effect was observed in the cell lines, where the expression of most receptors was affected by incubation with microbial mimics (LPS and PolyI:C) or the pro-inflammatory cytokine rIFN-γ. In addition, expression of the four receptors was modulated by viral infection, suggesting a potential involvement of such receptors and their ligands in antiviral defence.

[Low expression of Tlr-1, -2, -4 a il-2, -2r, -10, -10r and TgFb1 in pseudosynovial tissue collected at revision total knee arthroplasty for aseptic loosening]

PURPOSE OF THE STUDY

Aseptic loosening (AL) and periprosthetic osteolysis (PPOL) in total hip (THA) and knee (TKA) arthroplasty are linked to an inflammatory process initiated by wear debris released from artificial joints. There is still limited information about the contribution of Toll-like receptors (TLRs) and distinct regulatory cytokines to AL/PPOL in both joints.

METHODS

In this study, we investigated mRNA expression of TLR-1,-2,-4 and cytokines/receptors (IL-2,-2R,-10,-10R, TGFb1) in pseudosynovial tissue obtained from 55 patients with aseptically failed THAs/TKAs and 37 control patients with hip/knee primary osteoarthritis (OA) using quantitative RT-PCR. Immunohistochemical staining was used to detect the corresponding proteins. Non-parametric Kruskal-Wallis and Mann-Whitney tests were used to determine differences between the patient groups.

RESULTS

When comparing expression profiles between patients with aseptically failed THA and TKA, higher amounts of TLR-1,- 2,-4 and IL-2R mRNA transcripts were detected in THA patients. The mRNA expression of studied molecules (TLR-1,-2,-4, IL-2, IL-10, IL-2R, IL-10R, TGFb1) did not differ between THA and OA hip tissues. Lower mRNA expression of TLR-1,-2,- 4, IL-10, and IL-10R was detected in TKA when compared to control knee OA. Similar mRNA profiles of IL-2, IL-2R, and TGFb1 were observed in TKA and knee OA. Using immunohistochemistry, we detected low expression of TLR-1 protein in failed THA/TKA, whereas TLR-2 protein levels were higher in TKA/THA patients than in OA controls. High individual variability in TLR-4 protein levels was detected among patients with aseptically loosened THA and TKA. IL-10 protein levels were similar in THA and TKA patient subgroups and control subjects, whereas IL-10R protein level was higher in failed TKAs and OA controls than in THAs. No difference in IL-2 protein levels was detected between patients with THA/TKA and those with OA.

DISCUSSION

Our data indicate close similarity between the expression patterns in aseptically failed THA and TKA. However, certain differences were observed which also suggest unique pathways associated with the end-stage of aseptic loosening in THA and TKA. For instance, differences in the size, shape and load of polyethylene particles between THA and TKA could play some role. The composition of THA and TKA and differences in terms of mechanical forces might also be involved.

CONCLUSIONS

This is the fist study comparing the gene expression profile of a particular set of innate immunity regulatory molecules between tissues from aseptically failed THA and TKA. Low expression of TLR-1,-2,-4 and cytokines/receptors (IL-2, IL-2R, IL-10, IL-10R, and TGFb1) was observed in pseudosynovial tissues obtained from aseptically failed THAs and TKAs. Higher amount of TLR transcripts was detected in THA as compared to TKA. These findings indicate certain differences in the mechanism of aseptic loosening occurring at the site of THA and TKA. Further research is warranted.

Th22 cells are expanded in multiple sclerosis and are resistant to IFN-β

Th1 and Th17 cells have been considered as effectors in mouse EAE and in the human counterpart, MS. Recently, IL-22, a Th17-related, proinflammatory cytokine, has been associated with a new Th cell subset, defined as Th22, involved in chronic inflammatory conditions, such as psoriasis; the role of IL-22 in MS has not yet been elucidated. Here, we report that similar to Th17 cells, the number of Th22 cells increased in the PB and the CSF of RR MS patients, especially during the active phases of the disease. However, as opposed to Th17 cells, the expansion of Th22 cells occurred before the active phases of the disease. Th22 cells were found to be specific for the autoantigen MBP and also expressed high levels of CCR6 and T-bet, as for Th17 cells, indicating that Th22 self-reactive cells could have CNS-homing properties and be pathogenic in active RRMS patients. Conversely to Th17 cells, Th22 cells displayed lower levels of IFNAR1 and were insensitive to IFN-β inhibition. These data suggest that expansion of Th22 cells in MS could be one of the factors that critically influence resistance to IFN-β therapy.

Interferon lambda 1 expression in cervical cells differs between low-risk and high-risk human papillomavirus-positive women

Persistent infection by high-risk (HR) human papillomavirus (HPV) types is a prerequisite for progression to cancer. HR-HPVs may lead to a deregulation of innate immunity by interfering with the epithelial type I interferon (IFN) response, whereas very little is known about type III IFNs, a key component of the mucosal antiviral response. This study reports a first attempt to evaluate the activation of type III IFN genes (IFN lambda 1-3), IFN lambda receptor genes (IFN-lambdaR1 and IL10R2), and IFN-induced genes (MxA, ISG15, ISG56) in HPV-positive and HPV-negative cervical cells from 154 women attending the gynecological unit of a university hospital in Rome. Despite an increased individual variability, a coordinated expression of several IFN lambda-related genes was observed. Furthermore, IFN lambda 1 and IFN-lambdaR1 genes were expressed at higher levels in cervical cells positive to low-risk (LR) HPV compared to HR-HPV and HPV-negative cells. Consistently, ISG15 expression was significantly higher in LR-HPV-infected women than in the other groups. Moreover, IFN lambda 1 expression decreased significantly with abnormal cytological results. This study is the first to show the activation of a type III IFN response in LR-HPV-positive cervical cells and suggests that the lack of this response in HR-HPV infection may be related to lesion progression.

Peripherally restricted acute phase response to a viral mimic alters hippocampal gene expression

We have previously shown that peripherally restricted acute phase response (APR) elicited by intraperitoneal (i.p.) injection of a viral mimic, polyinosinic-polycytidylic acid (PIC), renders the brain hypersusceptible to excitotoxic insult as seen from profoundly exacerbated kainic acid (KA)-induced seizures. In the present study, we found that this hypersusceptibility was protracted for up to 72 h. RT-PCR profiling of hippocampal gene expression revealed rapid upregulation of 23 genes encoding cytokines, chemokines and chemokine receptors generally within 6 h after PIC challenge. The expression of most of these genes decreased by 24 h. However, two chemokine genes, i.e., Ccl19 and Cxcl13 genes, as well as two chemokine receptor genes, Ccr1 and Ccr7, remained upregulated for 72 h suggesting their possible involvement in the induction and sustenance of seizure hypersusceptibility. Also, 12 genes encoding proteins related to glutamatergic and GABAergic neurotransmission featured initial upregulation or downregulation followed by gradual normalization. The upregulation of the Gabrr3 gene remained upregulated at 72 h, congruent with its plausible role in the hypersusceptible phenotype. Moreover, the expression of ten microRNAs (miRs) was rapidly affected by PIC challenge, but their levels generally exhibited oscillating profiles over the time course of seizure hypersusceptibility. These results indicate that protracted seizure susceptibility following peripheral APR is associated with a robust polygenic response in the hippocampus.

Early-life growth hormone treatment to offspring of undernourished mothers alters metabolic parameters in primary adipocytes in adulthood

Maternal undernutrition (UN) is associated with the development of obesity and metabolic complications in adult offspring. This study investigated the impact of preweaning growth hormone (GH) treatment on adipocyte functionality in adult male offspring. Sprague-Dawley rats were assigned either standard (C) or undernourished (UN) diet (50% ad libitum) throughout gestation. Postnatal day 3-21, male C/UN pups received either saline (CS, UNS) or GH (2.5 µg/g/d; CGH, UNGH) by subcutaneous injection. Primary adipocytes were isolated following the collagenase digestion of adipose tissue. Primary adipocytes from UN offspring had significantly increased the secretion of pro-inflammatory cytokines accompanied by increased cytokine/cytokine receptor expression. This correlated with increased TLR4/NF-κB signaling. While increased inflammatory potential was not observed in adipocytes derived from UNGH offspring, there was a clear alteration in the expression of genes relating to carbohydrate and lipid metabolism along with nutrient transporters. Overall, preweaning GH treatment alters detrimental patterns of development, which predispose UN offspring to obesity and insulin resistance.

Matrix metalloproteinase-28 deletion exacerbates cardiac dysfunction and rupture after myocardial infarction in mice by inhibiting M2 macrophage activation

RATIONALE

Matrix metalloproteinase (MMP)-28 regulates the inflammatory and extracellular matrix responses in cardiac aging, but the roles of MMP-28 after myocardial infarction (MI) have not been explored.

OBJECTIVE

To determine the impact of MMP-28 deletion on post-MI remodeling of the left ventricle (LV).

METHODS AND RESULTS

Adult C57BL/6J wild-type (n=76) and MMP null (MMP-28((-/-)), n=86) mice of both sexes were subjected to permanent coronary artery ligation to create MI. MMP-28 expression decreased post-MI, and its cell source shifted from myocytes to macrophages. MMP-28 deletion increased day 7 mortality because of increased cardiac rupture post-MI. MMP-28(-/-) mice exhibited larger LV volumes, worse LV dysfunction, a worse LV remodeling index, and increased lung edema. Plasma MMP-9 levels were unchanged in the MMP-28((-/-)) mice but increased in wild-type mice at day 7 post-MI. The mRNA levels of inflammatory and extracellular matrix proteins were attenuated in the infarct regions of MMP-28(-/-) mice, indicating reduced inflammatory and extracellular matrix responses. M2 macrophage activation was impaired when MMP-28 was absent. MMP-28 deletion also led to decreased collagen deposition and fewer myofibroblasts. Collagen cross-linking was impaired as a result of decreased expression and activation of lysyl oxidase in the infarcts of MMP-28(-/-) mice. The LV tensile strength at day 3 post-MI, however, was similar between the 2 genotypes.

CONCLUSIONS

MMP-28 deletion aggravated MI-induced LV dysfunction and rupture as a result of defective inflammatory response and scar formation by suppressing M2 macrophage activation.

Analysis of the antimicrobial responses of primary phagocytes of the goldfish (Carassius auratus L.) against Mycobacterium marinum

The slow growth rate of Mycobacterium spp. that infect humans coupled with a lack of reliable in vitro infection model systems has hindered the progress of research in host cell-mycobacteria interactions. Recent studies have utilized the relatively fast growing Mycobacterium marinum to examine the host-pathogen interface in natural fish hosts. Here we describe the use of primary goldfish monocyte and mature macrophage cultures to investigate the immune cell-M. marinum interactions. Live and heat-killed M. marinum abrogated the recombinant goldfish (rg)TNFα2 and rgIFNγ-induced monocyte reactive oxygen production. Live but not heat-killed M. marinum also ablated rgIFNγrel and rg-TNFα2 induced macrophage nitric oxide production. M. marinum induced significant changes in gene expression of select NADPH oxidase components and inflammatory cytokine receptors and up-regulated the expression of immunosuppressive genes IL-10, TGFβ1 and SOCS-3. The exposure of monocytes and mature macrophages to M. marinum caused an increase in the mRNA levels of several pro-inflammatory genes. Stimulation of monocytes and macrophages with rgTNFα2, rgIFNγ, or rgIFNγrel reduced the survival of intracellular mycobacteria. The characterization of the interaction between M. marinum and natural host-derived primary phagocyte cultures will enable future studies on the host-pathogen interactions in mycobacterial infections.

Antitumor activity of type III interferon alone or in combination with type I interferon against human non-small cell lung cancer

The antitumor activities of type III interferon (IFN) (interleukin [IL]-28 and IL-29) and the combination of type III IFN and type I IFN (IFN-α) were evaluated using human non-small cell lung cancer (NSCLC). The expression of type III and type I receptor complexes was detected in NSCLC lines. IL-29 significantly inhibited the in vitro growth of a wide range of NSCLC lines in a dose-dependent fashion. To a lesser degree, IL-28A also displayed growth inhibitory activity. Antitumor activity of type III IFN is associated with cell cycle arrest at the G1 phase and apoptosis. IL-29 upregulated cyclin-dependent kinase inhibitor p21Waf1/Cip1 in cells sensitive, but not insensitive, to antiproliferative activity, and knockdown of p21 with small interfering RNA largely attenuated the antiproliferative effect. Intratumoral and systemic administration of IL-29 inhibited OBA-LK1 and LK-1, but not A549, tumor growth in severe combined immunodeficiency mice. Immunohistochemical analyses demonstrated marked upregulated p21 and downregulated Ki-67 expression in tumors treated with IL-29. The interferon combination of IL-29 and IFN-α displayed a more effective antiproliferative effect and a more intense p21 expression than each reagent alone in vitro. Furthermore, interferon combination therapy suppressed in vivo NSCLC growth more effectively than interferon monotherapy. These findings demonstrate that type III IFN can mediate direct antitumor activities via increased p21 expression and induction of apoptosis and cooperate with type I IFN to elicit more efficient direct antitumor activities, and suggest the possibility that type III IFN might improve the efficacy and reduce the side-effects of type I IFN cancer therapy.

[Expression, purification and identification of fusion protein mTSLPR-Ig]

AIM

To construct an adenovirus vector (Ad-mTSLPR-Ig) expressing the fusion protein of the extracellular domain of mouse TSLPR and the Fc fragment of mouse Ig, further purify and assess the soluble fusion protein mTSLPR-Ig.

METHODS

The gene of mTSLPR extracellular domain was amplified from cDNA library of mouse thymus by PCR. Then an adenovirus vector (Ad-mTSLPR-Ig) expressing the fusion protein of mTSLPR and the Fc fragment of mouse Ig was constructed. After Ad-mTSLPR-Ig was transfected into COS-7 cells, the supernatants were collected. The fusion proteins in the supernatants were detected by double antibody sandwich ELISA. The soluble fusion proteins mTSLPR-Ig were purified by protein A affinity chromatography.

RESULTS

The gene sequence of Ad-mTSLPR-Ig was confirmed by DNA sequencing, and the recombinat adenoviruses harboring mTSLPR-Ig were successfully obtained after the infection of Ad-mTSLPR-Ig. Fusion proteins mTSLPR-Ig in the supernatants were detected by ELISA assay. The purified fusion protein were obtained by affinity chromatography, and identified by Western blot.

CONCLUSION

The soluble fusion proteins mTSLPR-Ig have been obtained successfully, which enables further study of its biological activity.

Role of the adipocyte-specific NF-κB activity in the regulation of IP-10 and T cell migration

Infiltration of immune cells into adipose tissue plays a central role in the pathophysiology of obesity-associated low-grade inflammation. The aim of this study was to analyze the role of adipocyte NF-κB signaling in the regulation of the chemokine/adipokine interferon-γ-induced protein 10 kDa (IP-10) and adipocyte-mediated T cell migration. Therefore, the regulation of IP-10 was investigated in adipose tissue of male C57BL/6J mice, primary human and 3T3-L1 preadipocytes/adipocytes. To specifically block the NF-κB pathway, 3T3-L1 cells stably overexpressing a transdominant mutant of IκBα were generated, and the chemical NF-κB inhibitor Bay117082 was used. Adipocyte-mediated T cell migration was assessed by a migration assay. It could be shown that IP-10 expression was higher in mature adipocytes compared with preadipocytes. Induced IP-10 expression and secretion were completely blocked by an NF-κB inhibitor in 3T3-L1 and primary human adipocytes. Stable overexpression of a transdominant mutant of IκBα in 3T3-L1 adipocytes led to an inhibition of basal and stimulated IP-10 expression and secretion. T cell migration was induced by 3T3-L1 adipocyte-conditioned medium, and both basal and induced T cell migration was strongly inhibited by stable overexpression of a transdominant IκBα mutant. In addition, with the use of an anti-IP-10 antibody, a significant decrease of adipocyte-induced T cell migration was shown. In conclusion, in this study, we could demonstrate that the NF-κB pathway is essential for the regulation of IP-10 in 3T3-L1 and primary human adipocytes. Adipocytes rather than preadipocytes contribute to NF-κB-dependent IP-10 expression and secretion. Furthermore, NF-κB-dependent factors and especially IP-10 represent novel signals from adipocytes to induce T cell migration.

MPTP-induced neuroinflammation increases the expression of pro-inflammatory cytokines and their receptors in mouse brain

Parkinson's disease (PD) is a common neurodegenerative disease characterised by a slow and progressive degeneration of dopaminergic neurons in the substantia nigra (SN). Despite intensive research, the cause of neuronal loss in PD is poorly understood. Inflammatory mechanisms have been implicated in the pathophysiology of PD. In this study, conducted on an experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model, we investigated the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6 and their receptors (IL-1RI, TNF-αRI, IL-6Rα) at the SN and caudate-putamen (CP) levels. In MPTP-treated animals we observed a significant increase in IL-1β, TNF-α and IL-6 mRNA expression levels both in the SN and CP in comparison with untreated mice. In addition, both mRNA and protein levels of IL-1RI, TNF-αRI and IL-6Rα were significantly enhanced in the SN of MPTP-treated mice in comparison to controls, whereas no significant differences were observed in the CP between treated and untreated mice. Overall, these results indicate a role of both pro-inflammatory cytokines and their receptors in the pathogenesis of PD.

Type III IFN interleukin-28 mediates the antitumor efficacy of oncolytic virus VSV in immune-competent mouse models of cancer

Innate immune effector mechanisms triggered by oncolytic viruses may contribute to the clearance of both infected and uninfected tumor cells in immunocompetent murine hosts. Here, we developed an in vitro tumor cell/bone marrow coculture assay and used it to dissect innate immune sensor and effector responses to intratumoral vesicular stomatitis virus (VSV). We found that the type III IFN interleukin-28 (IL-28) was induced by viral activation of innate immune-sensing cells, acting as a key mediator of VSV-mediated virotherapy of B16ova melanomas. Using tumor variants which differentially express the IL-28 receptor, we showed that IL-28 induced by VSV within the tumor microenvironment sensitizes tumor cells to natural killer cell recognition and activation. These results revealed new insights into the immunovirological mechanisms associated with oncolytic virotherapy in immune-competent hosts. Moreover, they defined a new class of tumor-associated mutation, such as acquired loss of responsiveness to IL-28 signaling, which confers insensitivity to oncolytic virotherapy through a mechanism independent of viral replication in vitro. Lastly, the findings suggested new strategies to manipulate immune signals that may enhance viral replication, along with antitumor immune activation, and improve the efficacy of oncolytic virotherapies.

Current status and challenges of cytokine pharmacology

The major concern of pharmacology about cytokines has originated from plentiful data showing association between gross changes in their production and pathophysiological processes. Despite the enigmatic role of cytokines in diseases, a number of them have become a subject of cytokine and anti-cytokine immunotherapies. Production of cytokines can be influenced by many endogenous and exogenous stimuli including drugs. Cells of the immune system, such as macrophages and lymphocytes, are richly endowed with receptors for the mediators of physiological functions, such as biogenic amines, adenosine, prostanoids, steroids, etc. Drugs, agonists or antagonists of these receptors can directly or indirectly up- and down-regulate secretion of cytokines and expression of cytokine receptors. Vice versa, cytokines interfere with drug pharmacokinetics and pharmacodynamics through the interactions with cytochrome P450 and multiple drug resistance proteins. The aim of the review is to encourage more intensive studies in these fields of cytokine pharmacology. It also outlines major areas of searching promising candidates for immunotherapeutic interventions.

Respiratory syncytial virus synergizes with Th2 cytokines to induce optimal levels of TARC/CCL17

Respiratory syncytial virus (RSV) is a ubiquitous virus that preferentially infects airway epithelial cells, causing asthma exacerbations and severe disease in immunocompromised hosts. Acute RSV infection induces inflammation in the lung. Thymus- and activation-regulated chemokine (TARC) recruits Th2 cells to sites of inflammation. We found that acute RSV infection of BALB/c mice increased TARC production in the lung. Immunization of BALB/c mice with individual RSV proteins can lead to the development of Th1- or Th2-biased T cell responses in the lung after RSV infection. We primed animals with a recombinant vaccinia virus expressing either the RSV fusion (F) protein or the RSV attachment (G) protein, inducing Th1- and Th2-biased pulmonary memory T cell responses, respectively. After RSV infection, TARC production significantly increased in the vaccinia virus G-primed animals only. These data suggest a positive feedback loop for TARC production between RSV infection and Th2 cytokines. RSV-infected lung epithelial cells cultured with IL-4 or IL-13 demonstrated a marked increase in the production of TARC. The synergistic effect of RSV and IL-4/IL-13 on TARC production reflected differential induction of NF kappa B and STAT6 by the two stimuli (both are in the TARC promoter). These findings demonstrate that RSV induces a chemokine TARC that has the potential to recruit Th2 cells to the lung.

Expression of IL-27 p28 by Theiler's virus-infected macrophages depends on TLR3 and TLR7 activation of JNK-MAP-kinases

Theiler's murine encephalomyelitis virus (TMEV) causes a demyelinating disease (DD) due to infection of macrophages, stimulation of macrophage Toll-like receptor (TLR)3 and TLR7 pathways, activation of Mitogen-activated protein kinases (MAPK)s, and production of macrophages cytokines. Because expression of IL-27, a macrophage cytokine composed of p28 and EBI3 subunits, has been implicated in DD, we examined IL-27 subunit mRNA expression during TMEV infection of RAW264.7 cells, a macrophage cell line. TMEV infection of RAW264.7 cells did not affect cell viability, resulted in viral RNA replication, as well as p28 and EBI3 expression. Expression of p28 in TMEV-infected RAW264.7 cells depended on TLR3 and TLR7, as well as JNK but not p38 or ERK MAPKs. Since TMEV causes DD in SJL/J but not B10.S mice we determined the difference in expression of IL-27 subunit mRNA in SJL/J compared to B10.S macrophages. SJL/J macrophages expressed significantly more p28 mRNA after TMEV infection and after stimulation with TLR3 and TLR7 agonists compared with B10.S macrophages. Therefore, macrophages expression of IL-27 p28 mRNA in response to TMEV is due to activation of TLR3, TLR7, and JNK MAPKs pathways.

Memory generation and maintenance of CD8+ T cell function during viral persistence

During infection with viruses that establish latency, the immune system needs to maintain lifelong control of the infectious agent in the presence of persistent Ag. By using a gamma-herpesvirus (gammaHV) infection model, we demonstrate that a small number of virus-specific central-memory CD8+ T cells develop early during infection, and that virus-specific CD8+T cells maintain functional and protective capacities during chronic infection despite low-level Ag persistence. During the primary immune response, we show generation of CD8+ memory T cell precursors expressing lymphoid homing molecules (CCR7, L-selectin) and homeostatic cytokine receptors (IL-7alpha, IL-2/IL-15beta). During long-term persistent infection, central-memory cells constitute 20-50% of the virus-specific CD8+ T cell population and maintain the expression of L-selectin, CCR7, and IL-7R molecules. Functional analyses demonstrate that during viral persistence: 1) CD8+ T cells maintain TCR affinity for peptide/MHC complexes, 2) the functional avidity of CD8+ T cells measured as the capacity to produce IFN-gamma is preserved intact, and 3) virus-specific CD8+ T cells have in vivo killing capacity. Next, we demonstrate that at 8 mo post-virus inoculation, long-term CD8+ T cells are capable of mediating a protective recall response against the establishment of gammaHV68 splenic latency. These observations provide evidence that functional CD8+ memory T cells can be generated and maintained during low-load gammaHV68 persistence.

IL-2 is essential for TGF-beta to convert naive CD4+CD25- cells to CD25+Foxp3+ regulatory T cells and for expansion of these cells

IL-2 and TGF-beta both have important roles in the induction and maintenance of immunologic tolerance, but whether these cytokines act separately or together to achieve this effect is poorly understood. Although others have reported that IL-2 can directly enhance forkhead box protein P3 (Foxp3) transcription factor expression by natural CD4(+)CD25(+) regulatory T cells, in this study, we report that the role of IL-2 on the generation of peripheral regulatory CD4(+) cells is indirect. Ab neutralization studies and experiments with IL-2-deficient mice have revealed that IL-2 is required for TGF-beta to induce naive CD4(+)CD25(-) cells to become CD25(+) and express Foxp3, and develop the characteristic properties of CD4(+)CD25(+) regulatory cells. This effect of IL-2 on the generation and expansion of these adaptive Foxp3(+) regulatory cells is nonredundant, but IL-4, IL-7, and IL-15, other common gamma-chain cytokines, could sustain Foxp3 expression. Because subjects with autoimmune diseases often have defects in the production of IL-2 and/or TGF-beta, the generation of autologous T regulatory cells ex vivo with these cytokines for transfer in vivo may have considerable therapeutic potential.

Expression of autocrine motility factor mRNA is a poor prognostic factor in high-grade astrocytoma

It has been reported that tumor infiltration is correlated with the expression of autocrine motility factor (AMF) and its receptor 78 kDa glycoprotein (gp78). The purpose of the present study was to detect AMF and gp78 mRNA expression levels and their localization in high-grade astrocytomas (glioblastoma and anaplastic astrocytoma) and to determine whether AMF and gp78 are important prognostic factors. A total of 32 formalin-fixed and paraffin-embedded glioblastomas and 23 formalin-fixed and paraffin-embedded anaplastic astrocytomas was used. The expressions of AMF and gp78 mRNA were detected using the highly sensitive in situ hybridization method. The expression of AMF mRNA was detected in 27 of 32 glioblastomas (84.4%) and 11 of 23 anaplastic astrocytomas (47.8%). The positivity of AMF mRNA was significantly higher in glioblastomas than in anaplastic astrocytomas (P = 0.0094), but gp78 mRNA was detected in most cases and no statistical significance was observed. The overall survival of patients with AMF expression was significantly shorter than patients without AMF expression (P = 0.0175). In anaplastic astrocytomas, the overall survival of patients with AMF expression was also significantly shorter than in patients without AMF expression (P = 0.0058). This study demonstrated that AMF is a poor prognostic factor in high-grade astrocytomas.

SOCS-1 protects from virally-induced CD8 T cell mediated type 1 diabetes

CD8(+) cytotoxic T lymphocytes (CTL) can rapidly kill beta-cells and therefore contribute to the development of type 1 diabetes (T1D). CTL-mediated beta-cell killing can occur via perforin-mediated lysis, Fas-Fas-L interaction, and the secretion of TNF-alpha or IFN-gamma. The secretion of IFN-gamma can contribute to beta-cell death directly by eliciting nitric oxide production, and indirectly by upregulating MHC class I and 'unmasking' beta-cells for recognition by CTL. Earlier studies in the RIP-LCMV mouse model of diabetes showed that disruption of beta-cell IFN-gamma signaling alone abolished the direct detrimental effects of IFN-gamma, but not MHC class I upregulation. Suppressor of cytokine signaling-1 (SOCS-1) represses several crucial cytokine signaling pathways simultaneously, among them IFN-gamma and IL-1-beta. We therefore evaluated the protective capacity of islet cell SOCS-1 expression in the CD8(+) mediated RIP-LCMV diabetes model. Clinical disease was prevented in over 90% of the mice. Not only absence of MHC-I and Fas upregulation, but also resistance to cytokine-induced killing of beta-cells and a complete lack of CXCL-10 (IP10) production in islets led to a lack of islet infiltration and impaired activation of autoaggressive CD4(+) and CD8(+) T-cells in these mice. Thus, SOCS expression renders beta-cells resistant to CTL attack in a mouse model of T1D.

Follicular B helper T cell activity is confined to CXCR5(hi)ICOS(hi) CD4 T cells and is independent of CD57 expression

The generation of high-affinity antibody-secreting plasma cells critically depends on the presence of CD4 T cells during the germinal center (GC) reaction. GC T cells are so far incompletely characterized in terms of phenotype and function. Here, we show that human follicular B helper T (T(FH)) cells are characterized by high expression of the homeostatic chemokine receptor CXCR5 and the costimulatory molecule ICOS, but not CD57 expression. CXCR5(hi)ICOS(hi) CD4 T cells are the most potent inducers of IgG production that also secrete large amounts of the B cell-attracting chemokine CXCL13. CXCR5(hi)ICOS(hi) CD4 T cells differ from other tonsillar CD4 T cell subsets in their stimulatory activity, proliferative capacity and susceptibility to apoptosis. Large-scale gene expression analysis revealed that T(FH) cells are only distantly related to CXCR5(-) and CXCR5(+) central memory T (T(CM)) as well as effector memory T (T(EM)) cells present in the periphery. CXCR5(hi)ICOS(hi) CD4 T cells appear to be terminally differentiated T helper cells that express a unique set of transcription factors related to the Notch signaling pathway and thus differentiate independent of other T helper cell populations.

Dissecting CXCR5+ T cell populations--on the quest for a better understanding of B cell help during T dependent antibody responses

High affinity antibody responses against protein antigens critically depend on T cell help during the germinal center reaction. So called follicular helper T cells (T(FH)), present in the germinal centers of human tonsils, have been characterised by the expression of CXCR5; however, only subgroups of the heterogeneous CXCR5 T cell population strongly support antibody production. A paper in this issue of the European Journal of Immunology demonstrates that high expression of the inducible co-stimulator (ICOS) molecule, rather than CD57, correlates with the follicular helper function. This result represents another step towards a better understanding of the complexity of the different T cell subpopulations participating in the germinal center reaction.

Mphi1 and Mphi2 can be re-polarized by Th2 or Th1 cytokines, respectively, and respond to exogenous danger signals

Macrophages (Mphi) represent a dynamic cell population that develops and operates within a changing microenvironment. In parallel to Th1/Th2 cells, primary Mphi may undergo classical (Mphi1) or alternative (Mphi2) activation. Here, we investigated whether Mphi1/Mphi2 may be re-polarized by a secondary stimulation by Th1 or Th2 cytokines or by exogenous danger signals. We established that Mphi1IFNgamma respond to alternative activation by IL-4 and IL-10 by de novo secretion of Th2 cytokines AMAC-1 and IL-1ra, and by an increase in phagocytic capacity and a decrease in bactericidal activity. Vice versa, Mphi2 responded to classical activation by IFNgamma exhibiting reduced phagocytosis and significantly increased bacterial killing while being refractory regarding secretion of TNFalpha, IL-1beta and IL-12. In response to the bacterial danger signals LPS and MDP, both Mphi1 and Mphi2 produced IL-1beta and TNFalpha; in addition Mphi2 expressed the Th1-inducing cytokine IL-12. The ability of Mphi to be re-polarized and to react to exogenous danger signals is a precondition to down-regulate an outdated immune reaction and to retain the capacity to mount an adequate anti-bacterial response. Selective refractoriness of Mphi1 and Mphi2 to IFNgamma- and LPS-induced cytokine secretion may contribute to prevent autoimmunity.

CXC chemokine ligand 13 plays a role in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a Tcell-mediated autoimmune disease of the CNS that is widely used as an animal model of multiple sclerosis. In this study, we investigate the role of CXCL13, a chemokine involved in the development and organization of secondary lymphoid tissues, in the pathogenesis of EAE. We detected CXCL13 mRNA and protein in spinal cords of mice with EAE. CXCL13-deficient mice exhibited a mild, self-limited form of disease. CXCL13 appeared to be important for the establishment of chronic white matter lesions. Furthermore, adoptive transfer experiments with CXCL13-deficient hosts indicate that the chemokine plays a distinct role during the effector phase. Our findings raise the possibility that reagents that antagonize or inhibit CXCL13 might be useful for the treatment of neuroinflammatory diseases such as multiple sclerosis.

The effect of IL-1β on the expression of inflammatory cytokines and their receptors in human chondrocytes

Cytokines released at sites of inflammation and infection can alter the normal processes of cartilage turnover, resulting in pathologic destruction or formation. Interleukin (IL)-1beta plays a central role in the pathophysiology of cartilage damage and degradation in arthritis. In the present study, we examined the effect of IL-1beta on the expression of IL-1beta, IL-6, IL-8, IL-11, tumor necrosis factor-alpha (TNF-alpha), and their receptors in human chondrocytes. The cells were cultured either with or without 100 U/ml of IL-1beta for up to 28 days. The level of expression of the cytokines and their receptors was estimated by determining mRNA levels using real-time PCR or by determining protein levels using ELISA. The expression of IL-1beta, IL-8, and TNF-alpha markedly increased in the presence of IL-1beta after day 14 of culture. The expression of IL-6 and IL-11 increased greatly in the presence of IL-1beta on day 1 and after day 14 of culture. The expression of IL-1beta, IL-8, IL-11, and TNF-alpha receptors significantly decreased in the presence of IL-1beta after day 14 of culture, whereas the expression of IL-6 receptor significantly increased. The expression of these cytokines, except for IL-6, decreased with the addition of human IL-1 receptor antagonist. These results suggest that IL-1beta promotes the resolution system of cartilage matrix turnover through an increase in inflammatory cytokine production by chondrocytes and that it also may promote the autocrine action of IL-6 through an increase in IL-6 receptor expression in the cells.

Functional genomics of innate host defense molecules in normal human monocytes in response to Aspergillus fumigatus

Aspergillus fumigatus induces the release of innate immune-related molecules from phagocytic cells early in the course of infection. Little is known, however, about the complex expression profiles of the multiple genes involved in this response. We therefore investigated the kinetics of early gene expression in human monocytes (HMCs) infected with conidia of A. fumigatus using DNA microarray analysis. Total RNA from HMCs at 0, 2, 4, and 6 h was extracted, linearly amplified, hybridized onto Affymetrix HG133 Plus 2.0 gene chips, and analyzed with an Affymetrix scanner. Changes in gene expression were calculated as a ratio of those expressed by infected versus control HMCs. Aspergillus fumigatus induced differential regulation of expression in 1,827 genes (P < 0.05). Genes encoding cytokines and chemokines involved in host defense against A. fumigatus, including interleukin-1beta (IL-1beta), IL-8, CXCL2, CCL4, CCL3, and CCL20, as well as the opsonin long pentraxin 3, were up-regulated during the first 2 to 6 h, coinciding with an increase in phagocytosis. Simultaneously, genes encoding CD14, ficolin1, and MARCO were down-regulated, and genes encoding IL-10 and matrix metalloproteinase 1 were up-regulated. Up-regulation of the genes encoding heat shock proteins 40 and 110 and connexins 26 and 30 may point to novel molecules whose role in the pathogenesis of aspergillosis has not been previously reported. Verification of the transcriptional profiling was obtained for selected genes by reverse transcription-PCR and enzyme immunoassay. Thus, A. fumigatus conidia induced a coordinated expression of genes important in host defense and immunomodulation.

Molecular basis of age-associated cytokine dysregulation in LPS-stimulated macrophages

Aged humans and rodents are susceptible to infection with Streptococcus pneumoniae bacteria as a result of an inability to make antibodies to capsular polysaccharides. This is partly a result of decreased production of proinflammatory cytokines and increased production of interleukin (IL)-10 by macrophages (Mphi) from aged mice. To understand the molecular basis of cytokine dysregulation in aged mouse Mphi, a microarray analysis was performed on RNA from resting and lipopolysaccharide (LPS)-stimulated Mphi from aged and control mice using the Affymetrix Mouse Genome 430 2.0 gene chip. Two-way ANOVA analysis demonstrated that at an overall P < 0.01 level, 853 genes were regulated by LPS (169 in only the young, 184 in only the aged, and 500 in both). Expression analysis of systematic explorer revealed that immune response (proinflammatory chemokines, cytokines, and their receptors) and signal transduction genes were specifically reduced in aged mouse Mphi. Accordingly, expression of Il1 and Il6 was reduced, and Il10 was increased, confirming our previous results. There was also decreased expression of interferon-gamma. Genes in the Toll-like receptor-signaling pathway leading to nuclear factor-kappaB activation were also down-regulated but IL-1 receptor-associated kinase 3, a negative regulator of this pathway, was increased in aged mice. An increase in expression of the gene for p38 mitogen-activated protein kinase (MAPK) was observed with a corresponding increase in protein expression and enzyme activity confirmed by Western blotting. Low doses of a p38 MAPK inhibitor (SB203580) enhanced proinflammatory cytokine production by Mphi and reduced IL-10 levels, indicating that increased p38 MAPK activity has a role in cytokine dysregulation in the aged mouse Mphi.

Oncostatin M differentially regulates CXC chemokines in mouse cardiac fibroblasts

Ischemia-reperfusion injury in the heart is characterized by marked infiltration of neutrophils in the myocardial interstitial space. Studies in human, canine, and murine models have revealed oncostatin M (OSM) expression in infiltrating leukocytes. In an effort to assess possible roles of OSM in the myocardium, we used cardiac fibroblasts (mCFs) isolated from adult mouse heart to determine whether recombinant murine OSM regulates the synthesis and release of MIP2/CXCL2, KC/CXCL1, and LIX/CXCL5, which are three potent neutrophil chemoattractants in the mouse. Our results demonstrate that mCFs express OSM receptors and that, within the IL-6 cytokine family, OSM uniquely induces significant release of KC and LIX in mCFs. In addition, although OSM activates the JAK-signal transducers and activators of transcription and MAPK pathways, we demonstrate that the OSM-mediated CXC chemokine release in mCFs is also dependent on the activation of the phosphatidylinositol 3-kinase pathway.

Follicular B helper T cells in antibody responses and autoimmunity

T-cell help for B cells is essential for high-affinity antibody responses and B-cell memory. Recently, the identity of a discrete follicular population of T cells that has a crucial role in this process has become clearer. Similar to primed CD4(+) T cells in the tonsils and memory CD4(+) T cells in the peripheral blood, this follicular population of T cells expresses CXC-chemokine receptor 5 (CXCR5). Owing to their distinct homing preferences and helper function, these T cells differ from T helper 1 and T helper 2 cells and have been denoted follicular B helper T cells. Here, we outline the central role of this subset in normal and pathological immune responses.

Microarray Analysis of VEGF-C Responsive Genes in Human Lymphatic Endothelial Cells

Vascular endothelial growth factor-C (VEGF-C) is considered one of the most important factors influencing lymphatic endothelial cell biology. The goal of this work was to characterize the gene expression response by lymphatic endothelial cells (LECs) to VEGF-C. Primary cultures of human microvascular LECs were exposed to 100 ng/mL VEGF-C for 30 minutes and 6 hours, and their lysates were evaluated by microarray analysis to determine changes in mRNA expression induced by VEGF-C. Characteristic of a response to a growth factor stimulus, the largest number of differentially expressed genes were transcription factors and cell cycle related. A number of genes known to be important in angiogenesis, tumorigenesis and tumor invasion, and the transport of proteins, solutes, and lipids were also affected. Interestingly, a number of genes related to lipid metabolism as well as neurogenesis and neurodegeneration were also responsive to VEGF-C stimulation. Further analysis of these genes may not only provide insight into the molecular mechanisms underlying lymphangiogenesis and associated pathogenesis, but may also identify other important roles of VEGF-C.

The role of ICOS in the CXCR5+ follicular B helper T cell maintenance in vivo

ICOS is a new member of the CD28 family of costimulatory molecules that is expressed on activated T cells. Its ligand B7RP-1 is constitutively expressed on B cells. Although the blockade of ICOS/B7RP-1 interaction inhibits T cell-dependent Ab production and germinal center formation, the mechanism remains unclear. We examined the contribution of ICOS/B7RP-1 to the generation of CXCR5+ follicular B helper T (T(FH)) cells in vivo, which preferentially migrate to the B cell zone where they provide cognate help to B cells. In the spleen, anti-B7RP-1 mAb-treated or ICOS-deficient mice showed substantially impaired development of CXCR5+ T(FH) cells and peanut agglutinin+ germinal center B cells in response to primary or secondary immunization with SRBC. Expression of CXCR5 on CD4+ T cells was associated with ICOS expression. Adoptive transfer experiments showed that the development of CXCR5+ T(FH) cells was enhanced by interaction with B cells, which was abrogated by anti-B7RP-1 mAb treatment. The development of CXCR5+ T(FH) cells in the lymph nodes was also inhibited by the anti-B7RP-1 mAb treatment. These results indicated that the ICOS/B7RP-1 interaction plays an essential role in the development of CXCR5+ T(FH) cells in vivo.

Characterization of the murine immunological signaling network with phosphospecific flow cytometry

The immune system is a multitiered network that at the first level uses changes to intracellular signaling proteins to commit cells to determined fates. At the second tier, cells interact with one another via specifically expressed surface receptors and their cognate signaling molecules. At the third level, the local environments of immune cells change the outcomes of intracellular signaling pathways and thereby the role of cells during immune challenge. The interplay among these three tiers allows the distinct cell types of the immune system to respond cohesively to eliminate foreign Ags. In this study, using phosphospecific flow cytometry, we analyze elements of these network tiers by generating profiles of single-cell phosphoprotein responses in B cells, T cells, and myeloid cells to a number of mechanistically and clinically relevant cytokines (IFN-gamma, GM-CSF, IL-2, and IL-10) as well as LPS at key regulatory interfaces (Jak-Stat and MAPK pathways). The stimuli typically induced phosphorylation of specific signaling pathways and exerted their effects on distinct subsets of immune cells. However, upon comparison of stimulation in vitro and in vivo, we noted that signaling pathway specificity and cell type specificity were influenced strongly by the external environment. When taken from the in vivo environment, certain cell subsets became hypo- or hyper-responsive, showed profound differences in sensitivity to cytokine levels, or displayed altered phosphorylation kinetics. Thus, simultaneous analysis of the three tiers of the immune system network illustrates the principles by which immune regulation is context dependent and how in vitro culture systems compare with the in vivo environment.

A subset of human rapidly self-renewing marrow stromal cells preferentially engraft in mice

Controversies have arisen as to whether adult stem cells or progenitor cells from bone marrow can engraft into nonhematopoietic tissues in vivo. To resolve some of the controversies, we developed a highly sensitive polymerase chain reaction-based single nucleotide polymorphism (PCR-SNP) assay for competitive engraftment of mixtures of stem/progenitor cells. We used the assay to follow engraftment in immunodeficient mice of subpopulations of the stem/progenitor cells from human bone marrow referred to as either mesenchymal stem cells or marrow stromal cells (MSCs). The engraftment into adult mice without induced tissue injury was low and variable, but there was preferential engraftment of a subpopulation of rapidly self-renewing MSCs (RS-MSCs) compared with a subpopulation of slowly renewing MSCs (SR-MSCs). After intravenous infusion, there was a tendency for the cells to engraft into the hippocampal region that was previously designated a "vascular niche." Migration assays suggested that preferential engraftment of RS-MSCs was in part explained by their expression of CXCR4 and CX3R1, the receptors for SDF-1 and fractalkine.

Chemokines in the ischemic myocardium: from inflammation to fibrosis

Myocardial infarction is associated with an inflammatory response leading to leukocyte recruitment, healing and formation of a scar. Members of the chemokine superfamily are rapidly induced in the infarcted myocardium and may critically regulate the post-infarction inflammatory response. CXCL8/Interleukin (IL)-8 is upregulated in the infarcted area and may induce neutrophil infiltration. In addition, mononuclear cell chemoattractants, such as the CC chemokines CCL2/Monocyte Chemoattractant Protein (MCP)-1, CCL3/Macrophage Inflammatory Protein (MIP)1alpha, and CCL4/MIP-1beta are expressed in the ischemic area, and may regulate monocyte and lymphocyte recruitment. However, chemokines may have additional effects on healing infarcts beyond their leukotactic properties. The CXC chemokine CXCL10/Interferon-y inducible Protein (IP)-10, a potent angiostatic factor with antifibrotic properties, is induced in the infarct and may prevent premature angiogenesis and fibrous tissue deposition, until the infarct is debrided and provisional matrix necessary to support granulation tissue ingrowth is formed. Chemokine induction in the infarct is transient, suggesting that inhibitory mediators (such as transforming growth Factor (TGF)-beta) may be activated suppressing chemokine synthesis and leading to resolution of inflammation and transition to fibrosis. Brief repetitive ischemia in mice also results in chemokine upregulation followed by suppression of chemokine synthesis and interstitial fibrosis, in the absence of myocardial infarction. Chemokine expression may play a role in the pathogenesis of non-infarctive ischemic cardiomyopathy, where early ischemia-induced chemokine expression may be followed by activation of inhibitory mediators that suppress inflammation, but induce fibrosis.

Expression of autocrine motility factor (AMF) and its receptor, AMFR, in human breast cancer

Autocrine motility factor (AMF) stimulates, via an autocrine route, the motility of cancer cells. The current study investigated the expression of AMF and its receptor, AMFR (gp78), in breast cancer and attempted to dissect a clinical link. Breast tumor tissues (n=120) and non-neoplastic normal tissues (n=32) were studied. AMF and AMFR distribution in tissues were assessed using immunohistochemistry and their transcripts were analyzed using RT-PCR and quantitative PCR. Median follow-up of the cohort was 10 years. Normal mammary epithelial cells, but not stromal and endothelial cells, weakly stained for AMF and AMFR. However, cancer cells showed stronger staining. Both AMF and AMFR transcripts were significantly higher in tumor than in normal tissues (p=0.003 and p=0.0001, respectively). High levels of AMF and AMFR were seen in patients who died of breast cancer (p=0.049, p=0.0435) and high AMF was also seen in patients who had local recurrence (p=0.039) compared with those who remained disease free. A significant correlation was seen between long-term survival and the AMFR:CK19 ratio, in which patients with high AMFR:CK19 ratio tumors had a significantly shorter survival (101.0 months, 80.6-121.4) compared with those with low ratio (136.0 months, 123.7-148.2), p=0.0331. In conclusion, AMF and AMFR are overexpressed in human breast cancer and are negatively associated with patients' clinical outcome. This strongly indicates that the AMF-AMFR complex plays an important role in the progression of breast cancer, as well as having a prognostic role.

Contributions of intrinsic renal cells to crescentic glomerulonephritis

The pro-inflammatory contributions of leukocytes, particularly macrophages and T cells, to the immunopathogenesis of proliferative forms of glomerulonephritis (GN) have been clearly established by various techniques, including in vivo depletion studies in experimental models. The evidence for an active pro-inflammatory role for intrinsic renal cells in GN has relied on studies demonstrating their production of pro-inflammatory mediators in vitro and during the development of GN. Until recently,the specific in vivo contributions of mediators from intrinsic renal cells to inflammatory injury in GN have proven difficult to define. Utilising 'chimeric' mice as a tool, several studies have explored the involvement of intrinsic renal cells via their production of cytokines and other key pro-inflammatory molecules. These studies provide evidence of important functional contributions of intrinsic renal cells to inflammatory injury in GN via their expression of cytokines, cytokine receptors, MHC-II and co-stimulatory molecules. They suggest a sequence of interactions between cytokines from leukocytes and intrinsic renal cells and important contributions of glomerular epithelial cell proliferation to crescent formation.

Association of B-1 B cells with follicular dendritic cells in spleen

Although CD5(+) B-1 B cells have been recognized as an infrequent B cell subset in mice for many years, attempts to identify their histologic location in normal mouse spleen have proven difficult due to both their paucity and low level expression of CD5. In this study we have studied V(H)11/D(H)/J(H) gene-targeted mice, V(H)11t, that develop elevated numbers of CD5(+) V(H)11/V(k)9 B cells with an anti-phosphatidylcholine (anti-PtC) autoreactive specificity, allowing B-1 B cell detection by anti-PtC Id-specific Abs in spleen section staining. Using this approach we found that anti-PtC B-1 cells first appear within the white pulp in neonates, expand in association with follicular dendritic cells (FDC), and localize more centrally than other (non-B-1) IgD(high) follicular B cells in adults. Among neonatal B cells, CD5(+) B-1 cells in both normal and V(H)11t mouse spleen and peritoneal cavity express the highest levels of CXCR5, which is important for FDC development. Injection of purified spleen or peritoneal B-1 cells into RAG knockout mice resulted in B-1 cell follicle formation in spleen, inducing FDC development and plasma cell generation. These results indicate that B-1 B cells are the first B cells to express fully mature levels of CXCR5, thereby promoting the development of FDC.

ATG induction therapy: long-term effects on Th1 but not on Th2 responses

Antithymocyte globulin (ATG) induction therapy is associated with an increased long-term risk of infection- and cancer-related death. To analyze long-term effects of ATG induction on lymphocyte function, we prospectively assessed CD4 helper function, B-cell/monocyte and cytokine responses in 84 renal transplant recipients (ATG, n = 44) up to 1 year post-transplant. A PWM-driven allogeneic coculture system was used to assess helper function of CD4+ T cells and T-cell-dependent B-cell responses. SAC I was used for T-cell-independent stimulation of B-cell cultures. In vitro cytokine secretion and serum soluble CD30 (sCD30) were determined by enzyme-linked immunosorbent assay (ELISA). ATG induced a persistent decrease of peripheral blood lymphocyte counts compared with non-ATG treatment because of a predominant decrease of CD4+ T cells (4 months, 1 year; P < 0.0005) which was associated with a decreased CD28 expression (1 year, P = 0.02) and CD4 cell interleukin 2 (IL-2) response (4 months, P < 0.0005). However, Th2 responses (CD4 help, CD4 cell IL-4 and IL-10 responses, sCD30), which proved to be predictive of graft outcome, were not affected, and neither was the secretion of the lymphoma growth factors IL-6 and IL-10 by B cells and monocytes. Our data show that ATG induction therapy in immunological high-risk patients induces a profound long-term decrease in cell counts and Th1 but not Th2 responses of CD4+ T cells which may explain long-term effects on infection and post-transplant lymphoproliferative disease (PTLD) incidence because of inadequate T-cell control.

Positive and Negative Regulation of the IL-27 Receptor during Lymphoid Cell Activation

Previous reports have focused on the ability of IL-27 to promote naive T cell responses but the present study reveals that surface expression of WSX-1, the ligand-specific component of the IL-27R, is low on these cells and that highest levels are found on effector and memory CD4(+) and CD8(+) T cells. Accordingly, during infection with Toxoplasma gondii, in vivo T cell activation is associated with enhanced expression of WSX-1, and, in vitro, TCR ligation can induce expression of WSX-1 regardless of the polarizing (Th1/Th2) environment present at the time of priming. However, while these data establish that mitogenic stimulation promotes expression of WSX-1 by T cells, activation of NK cells and NKT cells prompts a reduction in WSX-1 levels during acute toxoplasmosis. Together, with the finding that IL-2 can suppress expression of WSX-1 by activated CD4(+) T cells, these studies indicate that surface levels of the IL-27R can be regulated by positive and negative signals associated with lymphoid cell activation. Additionally, since high levels of WSX-1 are evident on resting NK cells, resting NKT cells, effector T cells, regulatory T cells, and memory T cells, the current work demonstrates that IL-27 can influence multiple effector cells of innate and adaptive immunity.

Thrombotic and bleeding complications in four subpopulations of patients with essential thrombocythemia defined by c-Mpl protein expression and PRV-1 mRNA levels

C-Mpl and PRV-1 expression was measured in a cohort of 48 patients with essential thrombocythemia (ET). A retrospective analysis was conducted to asses whether the presence of one or both markers correlates with a higher risk of developing thromboembolic complications. In this cohort, PRV-1 overexpression was associated with a significantly increased risk of thrombosis, whereas decreased c-Mpl expression was not. The results of this retrospective analysis must now be corroborated in a large, prospective trial of newly diagnosed patients.

IL-27 subunits and its receptor (WSX-1) mRNAs are markedly up-regulated in inflammatory cells in the CNS during experimental autoimmune encephalomyelitis

IL-27 (EBI3p28) is a recently discovered heterodimeric cytokine, which is functionally related to IL-23p40p19 and IL-12p40p35. IL-27 acts in synergy with IL-12 early during Th1 development from naive T cells. IL-27 functions through the WSX-1 and the gpl30 receptor subunits, which shares homology with the IL-12Rbeta2 subunit. We have previously reported that IL-23 is up-regulated in CD11b+ microglia/macrophages in the CNS during the early phase of experimental autoimmune encephalomyelitis (EAE), and thus may contribute to the early induction of EAE. In the present study, we examined the expression of IL-27 and its receptor in the CNS, spleen, and lymph nodes at different stages of EAE actively induced with myelin oligodendrocyte glycoprotein peptide(35-55). Our findings show that IL-27 EBI3 and p28 mRNA were up-regulated to a maximum level at the peak of disease in APC from the CNS and lymph nodes, but not in the spleen. Moreover, IL-27 receptor (WSX-1) expression was greatly up-regulated during the early stage of EAE in both the CNS and lymph nodes. Taken together, our data show that subunits of IL-27 and its receptor (WSX-1) mRNAs are markedly up-regulated in inflammatory cells in the CNS at the peak of disease. Thus, IL-27 produced by infiltrating cells in the CNS may regulate in a paracrine manner the Th1 response in EAE.

EBV-induced gene 3 transcription is induced by TLR signaling in primary dendritic cells via NF-kappa B activation

The EBV-induced gene 3 (EBI3) is expressed in dendritic cells (DCs) and part of the cytokine IL-27 that controls Th cell development. However, its regulated expression in DCs is poorly understood. In the present study we demonstrate that EBI3 is expressed in splenic CD8(-), CD8(+), and plasmacytoid DC subsets and is induced upon TLR signaling. Cloning and functional analysis of the EBI3 promoter using in vivo footprinting and mutagenesis showed that stimulation via TLR2, TLR4, and TLR9 transactivated the promoter in primary DCs via NF-kappaB and Ets binding sites at -90 and -73 bp upstream of the transcriptional start site, respectively. Furthermore, we observed that NF-kappaB p50/p65 and PU.1 were sufficient to transactivate the EBI3 promoter in EBI3-deficient 293 cells. Finally, induced EBI3 gene expression in DCs was reduced or abrogated in TLR-2/TLR4, TLR9, and MyD88 knockout mice, whereas both basal and inducible EBI3 mRNA levels in DCs were strongly suppressed in NF-kappaB p50-deficient mice. In summary, these data suggest that EBI3 expression in DCs is transcriptionally regulated by TLR signaling via MyD88 and NF-kappaB. Thus, EBI3 gene transcription in DCs is induced rapidly by TLR signaling during innate immune responses preceding cytokine driven Th cell development.

IL-12 family members: differential kinetics of their TLR4-mediated induction by Salmonella enteritidis and the impact of IL-10 in bone marrow-derived macrophages

The members of the IL-12 family of heterodimeric cytokines play a pivotal role in initiation and regulation of cell-mediated immunity. Best known is IL-12p70, which promotes an immune response towards T(h)1 bias. Other members of this family (IL-23, IL-27) are less well characterized in terms of induction and function. Using either heat-killed or viable Salmonella Enteritidis or LPS as a stimulus, the kinetics of mRNA production of each member of the IL-12 family (p19, p28, p35, p40, Ebstein-Barr-Virus-induced gene 3 (EBI-3)) were determined in BMDMPhi originating from wild-type, Toll-like receptor (TLR)2- and/or TLR4-deficient mice. It was found that following either type of stimulation, a characteristic mRNA expression pattern was observed for each cytokine subunit. Whereas p19 was induced early and transiently, p40 and p35 were up-regulated later and then continuously, but the secretion of IL-23 and IL-12p70 was significantly reduced by IL-10. The up-regulation of p28 mRNA occurred also delayed and declined afterwards, whereas the initial high-level expression of EBI-3 remained almost unchanged in BMDMPhi. Furthermore, a splice variant of the EBI-3 mRNA was discovered. In this context, the cytokine mRNA up-regulation by whole Salmonella Enteritidis is mediated chiefly by TLR4, but depends on additional pattern recognition receptors other than TLR2 expressed by macrophages.

Interferon-gamma production by human cord blood monocyte-derived dendritic cells

Interferon (IFN)-gamma is produced by T cells and natural killer cells and activates monocytes and dendritic cells (DCs). Recently, IFN-gamma has been shown to be produced by mouse DCs following stimulation with interleukin (IL)-12, which is markedly augmented by the addition of IL-18. We here analyzed whether human DCs secrete IFN-gamma in response to IL-12 and/or IL-18. Human immature DCs, generated from cord blood CD14(+) monocytes by treating with granulocyte-macrophage colony-stimulating factor and IL-4, were incubated with IL-12 and/or IL-18 and assayed for IFN-gamma production. IL-12, but not IL-18, weakly induced IFN-gamma production, while IL-12 together with IL-18 induced high levels of IFN-gamma production. Similar results were obtained with mature DCs, although levels of IFN-gamma production were less than those in immature DCs. Also with mature and immature DCs, IL-12 upregulated the expression of IL-18 receptor alpha (Ralpha), and costimulation with IL-12 and IL-18 upregulated CD40 expression. Anti-IL-18Ralpha antibody abrogated both the IFN-gamma induction and the CD40 upregulation by IL-12 plus IL-18. These findings suggest that IL-12 upregulates IL-18Ralpha expression on human DCs and acts synergistically with IL-18 to induce high levels of IFN-gamma, which subsequently enhances CD40 expression on DCs in an autocrine manner.

Gene expression profiles of periodontal ligament cells treated with enamel matrix proteins in vitro: analysis using cDNA arrays

BACKGROUND

A number of procedures have been used to achieve periodontal regeneration. Recently, enamel matrix derivative (EMD) has been the subject of significant basic and clinical investigations. The precise molecular events involved in EMD modulation of periodontal wound healing are not completely understood; however, cDNA microarray technology may enable rapid and accurate examination of EMD-mediated changes in gene expression in periodontal ligament (PDL) cells in vitro. The present study was undertaken to explore the selective effects of EMD on the activities of 268 cytokine, growth factor, and receptor genes in PDL.

METHODS

PDL cells were cultured in the absence and presence of EMD at a concentration of 100 microg/ml for 4 days. RNA was extracted and used to generate labeled cDNA probes. These were hybridized to cDNA arrays comprising 268 genes and exposed to x-ray films. Autoradiographs were digitized and analyzed.

RESULTS

Forty-six percent (125 of 268) of the tested genes were found to be expressed by the PDL cells. Of these 125 genes, 38 were differentially expressed by PDL cells which had been cultured in the presence of EMD. Among the 38, 12 were found to be downregulated, notably mostly inflammatory genes, whereas 26 genes demonstrated upregulation, many of these coding for growth factors and growth factor receptors.

CONCLUSIONS

The present study has shown that EMD down-regulates the expression of genes involved in the early inflammatory phases of wound healing while simultaneously upregulating genes encoding growth and repair-promoting molecules. This may partly explain the apparent efficacy of EMD application in periodontal regeneration.

CXC chemokine ligand 16 promotes integrin-mediated adhesion of liver-infiltrating lymphocytes to cholangiocytes and hepatocytes within the inflamed human liver

Lymphocyte recruitment to the liver is critical for viral clearance in acute hepatitis and in the pathogenesis of chronic inflammatory liver disease when persistent chronic inflammation leads to fibrosis and cirrhosis. Chemokines regulate leukocyte recruitment and positioning in tissues and are thus critical regulators of chronic inflammation. The chemokine CXCL16, which is found in liver tissue, exists in a transmembrane as well as soluble form, providing a potential mechanism for localization to particular structures. We studied the role of CXCL16 and its receptor CXCR6 in lymphocyte recruitment and retention in the liver. A higher proportion of CXCR6(+) T cells was detected in blood of hepatitis C virus patients compared with healthy subjects, and in chronic inflammatory liver disease >60% of intrahepatic T cells expressed CXCR6, including CD4, CD8, and CD56(+) T cells compared with <30% in matched blood samples. CXCR6(+) lymphocytes were found in association with CXCL16(+) bile ducts in portal tracts and with hepatocytes at sites of interface hepatitis. Analysis of CXCL16 expression and subcellular distribution in cultured human cholangiocytes, sinusoidal endothelial cells, and hepatocytes revealed that all three cell types expressed CXCL16, with the strongest staining seen on cholangiocytes. CXCL16 on the cholangiocyte membrane was able to support lymphocyte adhesion by triggering conformational activation of beta(1) integrins and binding to VCAM-1. Thus, CXCL16 can promote lymphocyte adhesion to epithelial cells and may function to attract and retain effector cells that promote biliary and hepatocyte destruction in inflammatory liver disease.