Interleukin-36 potently stimulates human M2 macrophages,Langerhans cells and keratinocytes to produce pro-inflammatory cytokines

Interleukin (IL)-36 cytokines belong to the IL-1 family and include three agonists, IL-36 α, β and γ and one inhibitor, IL-36 receptor antagonist (IL-36Ra). IL-36 and IL-1 (α and β) activate similar intracellular pathways via their related heterodimeric receptors, IL-36R/IL-1RAcP and IL-1R1/IL-1RAcP, respectively. However, excessive IL-36 versus IL-1 signaling induces different phenotypes in humans, which may be related to differential expression of their respective receptors.We examined the expression of IL-36R, IL-1R1 and IL-1RAcP mRNA in human peripheral blood, tonsil and skin immune cells by RT-qPCR. Monocyte-derived dendritic cells (MDDC), M0, M1 or M2-polarized macrophages, primary keratinocytes, dermal macrophages and Langerhans cells (LC) were stimulated with IL-1β or IL-36β. Cytokine production was assessed by RT-qPCR and immunoassays.The highest levels of IL-36R mRNA were found in skin-derived keratinocytes, LC, dermal macrophages and dermal CD1a⁺ DC. In the blood and in tonsils, IL-36R mRNA was predominantly found in myeloid cells. By contrast, IL-1R1 mRNA was detected in almost all cell types with higher levels in tonsil and skin compared to peripheral blood immune cells. IL-36β was as potent as IL-1β in stimulating M2 macrophages, keratinocytes and LC, less potent than IL-1β in stimulating M0 macrophages and MDDC, and exerted no effects in M1 and dermal macrophages. Levels of IL-1Ra diminished the ability of M2 macrophages to respond to IL-1.Taken together, these data are consistent with the association of excessive IL-36 signaling with an inflammatory skin phenotype and identify human LC and M2 macrophages as new IL-36 target cells.     

Intracellular IL-1 receptor antagonist is elevated in human dermal fibroblasts that overexpress intracellular precursor IL-1 alpha.

Cultured dermal fibroblasts from systemic sclerosis patients express higher levels of intracellular IL-1 alpha than fibroblasts from healthy controls. In this study, we found that systemic sclerosis dermal fibroblasts also express higher levels of the intracellular isoform of IL-1 receptor antagonist (icIL-1Ra) than normal fibroblasts after stimulation with IL-1 beta or TNF-alpha. A possible relationship between elevated precursor IL-1 alpha (preIL-1 alpha) and elevated icIL-1Ra was investigated by transducing normal dermal fibroblasts to overexpress preIL-1 alpha, preIL-1 beta, or icIL-1Ra. Fibroblasts that overexpressed icIL-1Ra did not have elevated levels of IL-1 alpha. On the other hand, fibroblasts that overexpressed preIL-1 alpha had at least 4-fold higher basal levels of icIL-1Ra than control fibroblasts and 4-fold higher levels of icIL-1Ra after induction with IL-1 beta or TNF-alpha. Fibroblasts overexpressing preIL-1 beta did not exhibit elevated icIL-1Ra. The differences in icIL-1Ra protein levels were reflected in differences in mRNA. In contrast, IL-1-stimulated levels of MCP-1 and IL-6 were not different in control and preIL-1 alpha-transduced fibroblasts. Addition of neutralizing anti-IL-1 alpha Abs to fibroblast cultures did not diminish basal or stimulated levels of icIL-1Ra in the preIL-1 alpha-transduced cells, supporting an intracellular site of action of preIL-1 alpha. This is the first report of an association between intracellular levels of these IL-1 family members. We hypothesize that intracellular preIL-1 alpha participates in the regulation of icIL-1Ra.     

Adipose and liver expression of interleukin (IL)-1 family members in morbid obesity and effects of weight loss

Morbid obesity is associated with a state of chronic inflammation. Interleukin-1 family (IL-1F) cytokine members are produced by human adipose tissue in obesity. Whereas certain IL-1F members such as IL-1β or IL-18 are potently proinflammatory, others such as IL-1 receptor antagonist (IL-1Ra) or IL-37 (formerly IL-1F7) are antiinflammatory. The NLRP3 inflammasome plays a key role in the processing of bioactive IL-1β and IL-18. We investigated the effect of excessive weight loss on subcutaneous adipose tissue and liver expression of IL-1α, IL-1β, IL-18, IL-1Ra, IL-37 and NLRP3. Twenty-one severely obese patients undergoing laparoscopic adjustable gastric banding were studied. Tissue samples were collected before and 6 months after laparoscopic adjustable gastric banding surgery. mRNA expression of all studied IL-1F members, but especially of IL-37, was much higher in subcutaneous/visceral adipose tissue compared with their liver expression. Subcutaneous adipose tissue mRNA expression of IL-1β decreased significantly after extensive weight loss; expression of IL-18 and IL-1Ra did not change, whereas IL-37 expression increased. Weight loss led to a significant reduction in liver IL-1β, IL-18 and IL-1Ra expression, whereas hepatic IL-37 mRNA expression remained stable. Adipose/liver NLRP3 inflammasome and IL-1α expression were not affected by weight loss. Tissue expression of IL-1β, IL-18 and IL-37 were significantly higher in subcutaneous/visceral adipose tissue compared with the liver. In conclusion, expression of IL-1F members is more pronounced in adipose compared with liver tissue in patients with severe obesity. Excessive weight loss changes the adipose and liver expression profile of IL-1F members toward a more antiinflammatory direction.     

Expression of cytokine mRNA and protein in joints and lymphoid organs during the course of rat antigen-induced arthritis

Cytokine expression was assessed during antigen-induced arthritis (AIA) in synovial membrane (SM), inguinal lymph node (LN), and spleen using competitive RT-PCR and sandwich ELISA. In the SM, early elevations of IL-1β and IL-6 mRNA (by 6 hours; 450- and 200-fold, respectively) correlated with the joint swelling; a 6-fold increase in tumor necrosis factor α (TNFα) was not significant. Not only IL-2 and IFN-γ (which increased 10,000-fold and 200-fold, respectively), but also IL-5 and IL-10, increased acutely (6 hours – day 1; 3-fold and 35-fold, respectively) in the SM. In general, the protein levels in the SM for IL-1β, IL-6, TNFα, IFN-γ, IL-4, and IL-10 (increase from 4-fold to 15-fold) matched the course of mRNA expression. In the inguinal LN, there were early mRNA elevations of IL-6 (a 2.5-fold increase by 6 hours, which correlated positively with the joint swelling) and IL-2 (4-fold by 6 hours), as well as later rises of IL-4 and IL-5 (2.5- and 4-fold, respectively, by day 3). No significant elevations of the corresponding proteins in this tissue were observed, except for IL-1β (by day 6) and IL-10 (by day 1). In the spleen, there were significant mRNA elevations at 6 hours of IL-1β (1.5-fold), IL-6 (4-fold; positively correlated with the joint swelling), IFN-γ (3-fold), and IL-2 (7- to 10-fold). IL-5 and IL-10 (2- and 3-fold, respectively) peaked from 6 hours to day 3 in the spleen. Increases of the corresponding proteins were significant in comparison with day 0 only in the case of IL-2 (day 6). By day 6 (transition to the chronic phase), the mRNA for cytokines declined to or below prearthritis levels in all the tissues studied except for IL-1β in the SM and IL-6 in the spleen. AIA is thus characterized by four phenomena: early synovial activation of macrophages, T helper (Th)1-like, and Th2-like cells; late, well-segregated Th2-like responses in the inguinal LN; late, overlapping Th1-like/Th2-like peaks in the spleen; and chronic elevation of synovial IL-1β mRNA and spleen IL-6 mRNA.     

Interleukin-1 Receptor Antagonist Has a Novel Function in the Regulation of Matrix Metalloproteinase-13 Expression

Interleukin-1 receptor antagonist (IL-1Ra) is an IL-1 family member, which binds to IL-1 receptors but does not induce any intracellular signaling. We addressed whether IL-1Ra has a novel function in regulation of the extracellular matrix or adhesion molecules. Polymerase chain reaction array analysis demonstrated a ~5-fold increase in matrix metalloproteinase 13 (MMP-13) mRNA expression of IL-1Ra siRNA-transfected Ca9-22 human oral squamous epithelial carcinoma cells compared with the control. In fact, MMP-13 mRNA and protein expression as well as its activity in IL-1Ra siRNA-transfected Ca9-22 cell lines were significantly higher than those in the control. IL-1Ra siRNA treatment resulted in strong elevation of MMP-13 expression, whereas addition of rhIL-1Ra (40 ng/ml) suppressed MMP-13 expression, suggesting that IL-1Ra had a specific effect on MMP-13 induction. IL-1Ra siRNA could potently suppress IL-1α. No significant difference was found between the MMP-13 mRNA expression of IL-1Ra siRNA-transfected cells and those treated with anti-IL-1α or anti-IL-1β antibodies. These results suggested that continuous supply of IL-1 had no effect on the induction of MMP-13 by IL-1Ra siRNA. Histopathological investigation of MMP-13 in periodontal tissue showed specific localization in the junctional epithelial cells of IL-1Ra knockout (KO) mice. Furthermore, infection with Aggregatibacter actinomycetemcomitans to establish an experimental periodontitis model resulted in predominant localization of MMP-13 along apical junctional epithelial cells. Laminin-5, which is degraded by MMP-13, was found in the internal basal lamina of wild-type mice, whereas the internal basal lamina of IL-1Ra KO mice did not show obvious laminin-5 localization. In particular, laminin-5 localization almost disappeared in the internal basal lamina of IL-1Ra KO mice infected with A. actinomycetemcomitans, suggesting that the suppression of IL-1Ra resulted in strong induction of MMP-13 that degraded laminin-5. In conclusion, IL-1Ra is associated with MMP-13 expression and has a novel function in such regulation without interference of the IL-1 signaling cascade.     

Interleukin-1-mediated H2O2 production by hepatic sinusoidal endothelium in response to B16 melanoma cell adhesion

We have examined H₂O₂ production by in vitro enriched hepatic sinusoidal endothelium (HSE) during interleukin-1β (IL-1β) stimulation and B16 melanoma cell adhesion. Production of H₂O₂ was quantified by flow cytometry and multiwell plate-scanning fluorimetry of intracellular 2′, 7′-dichlorofluorescein (DCFH) oxidation in HSE. Under IL-1β treatment there was a 6-fold increase in endothelial cells producing H₂O₂ (67%) and a 4-fold augmentation in the Kupffer cell population (86%). The average H₂O₂ content per cell size unit significantly (P < 0.01) increased in endothelial cells (2.6-fold) and Kupffer cells (1.7-fold). In contrast to the homogeneity of Kupffer cells, H₂O₂ production intensity was largely heterogeneous in IL-1β-activated HSE. Enhancement of H₂O₂ production by IL-β-treated HSE started at the 4th h and peaked 2–3 h later. The addition of increasing concentrations of IL-1β to HSE for 4 h caused the progressive activation of H₂O₂ production by treated cells. The addition of 80 M excess of IL-1 receptor antagonist (IL-1Ra) 10 min before IL-1β treatment abrogated IL-1β-mediated enhancement of H₂O₂. From the 2nd h of B16 melanoma adhesion to HSE there was a significant (P < 0.05) enhancement of H₂O₂ content in HSE. This activation increased 2.25-fold by the 3rd h of coculture and had reduced again by the 5th h. IL-1Ra (80 ng/ml) given to HSE 10 min before melanoma cells abrogated the HSE response to melanoma cells. The addition of 1% paraformaldehyde (PFA)-fixed B16 melanoma cells to HSE did not affect H₂O₂ production response, indicating that HSE-activating agents were on the melanoma cell surface. Preincubation of B16 melanoma cells in the presence of 5 μg/ml anti-mouse IL-1β neutralizing antibody reduced the melanoma cell-induced HSE production of H₂O₂ by 80%. On the contrary, B16 melanoma cell-conditioned medium did not vary HSE production of H₂O₂ compared to control HSE. Western blot analysis of cytosolic and membrane sediments from B16 melanoma cells confirmed the presence of IL-1β (17.4 kDa) in both cell compartments. Thus, HSE responded to melanoma cell contact with a rapid production of H₂O₂. HSE activation was IL-1-dependent. This cytokine was directly provided to HSE by the cell surface of adhered melanoma cells. © 1996 Wiley-Liss, Inc.     

Modulation of the catabolic effects of interleukin-1β on human articular chondrocytes by transforming growth factor-β

The effects of IL-1β and TGF-β on the biosynthesis of extracellular matrix structural components relative to the metalloproteinases and their inhibitor TIMP1 in human articular chondrocytes were investigated. It has been proposed that TGF-β, acting as a positive regulator of matrix accretion, can counteract the increased loss of cartilage matrix induced by IL-1β. To allow a comparison of their effects on mRNA levels for these different components, quantitation by competitive RT/PCR was employed. This method was found to give reproducible estimates of mRNA levels and the observed effects of IL-1β and TGF-β on individual components of this system agree with qualitative data obtained by northern blotting. IL-1β had a more pronounced effect on aggrecan mRNA levels than on those for type II collagen. Similar quantitative differences were observed between collagenase and stromelysin mRNA levels. TGF-β generally counteracted the effects of IL-1β, and new steady state levels were attained within 24 h. However, the reversal of IL-1β induced suppression of matrix protein mRNA levels appeared more effective than its suppression of the increase in stromelysin and collagenase mRNA levels. Similarly TGF-β did not reduce the extent of IL-1β induced secretion of stromelysin at the protein level. TIMP1 mRNA levels were only slightly reduced by IL-1β; however this cytokine effectively surpressed its induction by TGF-β. The higher concentrations of TGF-β and longer exposure times required to overcome the surpressive effects of IL-1β suggest that the interaction between IL-1β and TGF-β in the regulation of TIMP1 expression follows a different mechanism to that operating for the metalloproteinases and matrix proteins. Thus the overall potential of TGF-β to inhibit proteolysis is attenuated by its much slower effect on TIMP1 mRNA levels. © 1996 Wiley-Liss, Inc.     

Effect of honey on mRNA expression of TNF-α, IL-1β and IL-6 following acute toxoplasmosis in mice

This study analyzed the mRNA expression of tumor necrosis factor (TNF-α), interleukin 1 beta (IL-1β) and interleukin 6 (IL-6) in mice experimentally infected with T. gondii undergoing honey treatment. Thirty male mice were divided in groups: pre-treatment/infected (1), infected/non-treated (2), infected/treated (3), non-infected/treated (4) and control (5). Honey was applied for groups 1, 3, 4 by gavage and the mice in group 1–3 were infected by T. gondii tissue cysts. The parasite load and the level of mRNA expression of the aforementioned cytokines in the brains of mice were assessed by qPCR. The mean number of T. gondii tachyzoite in 1 mg brain tissue was 32, 73 and 59 in groups one, two and three, respectively. The mRNA expression of TNF-α increased in group 1, 2 and 3, about 49.1%, 307.3% and 63.2%, respectively but it was down-regulated by 53% in group 4. The mRNA expression of IL-1β and IL-6 was also up-regulated in all groups except group 2. The mRNA level of TNF-α was reduced by 2.7-fold and 1.18-fold in pre-treated/infected (group 1) and infected/treated (group 3) compared with infected/non-treated (group 2). The mRNA level of IL-1β and IL-6 were increased in these groups. The current study demonstrated that honey can stimulate or suppress the mRNA expression of some pro-inflammatory cytokines in mice brains. Furthermore, honey suppresses the TNF-α mRNA expression in the presence of T. gondii infection but it stimulates the IL-1β and IL-6 mRNA expression. Treatment of the mice with honey reduces parasite multiplication in the brain.     

Regulation of spermidine/spermine N1-acetyltransferase expression by cytokines and polyamines in human hepatocarcinoma cells (HepG2)

Spermidine/spermine N¹-acetyltransferase (cSAT), a key enzyme in polyamine degradation, is induced by various hepatotoxins and liver tumor promoters. In this paper we demonstrate that physiological factors, such as cytokines, control cSAT expression in HepG2 human hepatocarcinoma cells. Hepatocyte growth factor (HGF) induced the cSAT mRNA precursor (3.5 kb) at 4 h. The mature form of mRNA (1.3 kb) increased 6–8-fold between 8 and 10 h, and remained elevated until 18 h. An increase in cSAT activity (2-fold) and high levels of N¹-acetylspermidine were observed concomitantly. Interleukin-1β (IL-1β) enhanced cSAT expression (both mRNA and enzyme activity) similar to HGF, while tumor necrosis factor-α (TNFα) was less effective. This system also provides a useful means for examining the involvement of negative and positive changes of polyamines in the induction of cSAT and c-jun, a gene that participates in the control of cSAT expression. α-Difluoromethylornithine (DFMO) pretreatment, by lowering putrescine and spermidine in HGF- or IL-1β-treated cells, prevented the induction of cSAT. This effect was reversed by exogenous putrescine or spermidine. IL-1β induced c-jun mRNA more than HGF. DFMO prevented almost completely the enhancement of c-jun mRNA expression by IL-1β, and this effect was reversed by exogenous putrescine or spermidine. Therefore, we suggest that cSAT and c-jun expression is specifically regulated by polyamine-mediated mechanisms in IL-1β treated HepG2 cells. Since cSAT is inducibile by cytokines that control tumor metabolism and growth as well as tumor-host interaction, we hypothesize an involvement of cSAT in hepatoma growth. J. Cell. Physiol. 174:125–134, 1998. © 1998 Wiley-Liss, Inc.     

Up-regulation of IL-23 p19 expression in human periodontal ligament fibroblasts by IL-1β via concurrent activation of the NF-κB and MAPKs/AP-1 pathways

Interleukin (IL)-23 is an essential cytokine involved in the expansion of a novel CD4(+) T helper subset known as Th17, which has been implicated in the pathogenesis of periodontitis recently. Our previous study first identified specialized human periodontal ligament fibroblasts (hPDLFs) as an important production source of IL-23. The present study was undertaken to investigate the effects of the pro-inflammatory and Th17-polarizing mediator IL-1β on hPDLFs-mediated IL-23 p19 production, and the molecular mechanism involved. IL-23 p19 expression was in situ detected in IL-1β-stimulated hPDLFs. IL-1β was capable of stimulating the expression of IL-23 p19 mRNA and protein in cultured hPDLFs, which was attenuated by IL-1 receptor antagonist (IL-1Ra) or myeloid differentiation primary response gene 88 (MyD88) inhibitor. Meanwhile, inhibitors of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK) 1/2, c-Jun-N-terminal kinase (JNK), activator protein-1 (AP-1), or nuclear factor-kappaB (NF-κB) significantly suppressed IL-23 p19 production from IL-1β-stimulated hPDLFs. Moreover, IL-1β-initiated AP-1 activation was blocked by p38 MAPK, ERK 1/2, or JNK inhibition, whereas NF-κB activity remained unaltered by all the above pathway specific inhibitors. Thus, these results provide evidence that Th17-polarizing mediator IL-1β up-regulated the expression of IL-23 p19 in hPDLFs via NF-κB signaling and MAPKs-dependent AP-1 pathways. Taken together, our findings indicate that IL-1Ra may be used therapeutically to inhibit Th17-driven inflammatory diseases including periodontitis.     

Interleukin-36 (IL-36) ligands require processing for full agonist (IL-36α, IL-36β, and IL-36γ) or antagonist (IL-36Ra) activity

IL-36α, IL-36β, and IL-36γ (formerly IL-1F6, IL-1F8, and IL-1F9) are IL-1 family members that signal through the IL-1 receptor family members IL-1Rrp2 (IL-1RL2) and IL-1RAcP. IL-36Ra (formerly IL-1F5) has been reported to antagonize IL-36γ. However, our previous attempts to demonstrate IL-36Ra antagonism were unsuccessful. Here, we demonstrate that IL-36Ra antagonist activity is dependent upon removal of its N-terminal methionine. IL-36Ra starting at Val-2 is fully active and capable of inhibiting not only IL-36γ but also IL-36α and IL-36β. Val-2 of IL-36Ra lies 9 amino acids N-terminal to an A-X-Asp motif conserved in all IL-1 family members. In further experiments, we show that truncation of IL-36α, IL-36β, and IL-36γ to this same point increased their specific activity by ～10(3)-10(4)-fold (from EC(50) 1 μg/ml to EC(50) 1 ng/ml). Inhibition of truncated IL-36β activity required ～10(2)-10(3)-fold excess IL-36Ra, similar to the ratio required for IL-1Ra to inhibit IL-1β. Chimeric receptor experiments demonstrated that the extracellular (but not cytoplasmic) domain of IL-1Rrp2 or IL-1R1 is required for inhibition by their respective natural antagonists. IL-36Ra bound to IL-1Rrp2, and pretreatment of IL-1Rrp2-expressing cells with IL-36Ra prevented IL-36β-mediated co-immunoprecipitation of IL-1Rrp2 with IL-1RAcP. Taken together, these results suggest that the mechanism of IL-36Ra antagonism is analogous to that of IL-1Ra, such that IL-36Ra binds to IL-1Rrp2 and prevents IL-1RAcP recruitment and the formation of a functional signaling complex. In addition, truncation of IL-36α, IL-36β, and IL-36γ dramatically enhances their activity, suggesting that post-translational processing is required for full activity.     

Berry anthocyanins suppress the expression and secretion of proinflammatory mediators in macrophages by inhibiting nuclear translocation of NF-κB independent of NRF2-mediated mechanism

The objectives of this study were to compare the anti-inflammatory effects of anthocyanins from blueberry (BBA), blackberry (BKA), and blackcurrant (BCA) and to determine the relationship between their antioxidant capacity and anti-inflammatory effect in macrophages. Major anthocyanins in BBA, BKA and BCA were malvidin-3-glucoside (16%), cyanidin-3-glucoside (98%) and delphinidin-3-rutinoside (44%), respectively. BKA showed higher total antioxidant capacity than BBA and BCA. RAW 264.7 macrophages were incubated with 0–20 μg/ml of BBA, BKA and BCA, and subsequently activated by lipopolysaccharide (LPS) to measure proinflammatory cytokine production. Interleukin 1β (IL-1β) messenger RNA (mRNA) levels were significantly decreased by all berry anthocyanins at 10 μg/ml or higher. Tumor necrosis factor α (TNFα) mRNA levels and secretion were also significantly decreased in LPS-treated macrophages. The levels of the repression were comparable for all berry anthocyanins. LPS-induced nuclear factor κB (NF-κB) p65 translocation to the nucleus was markedly attenuated by all of the berry anthocyanins. In bone marrow-derived macrophages (BMMs) from nuclear factor E2-related factor 2 wild-type (Nrf2^+/+) mice, BBA, BKA and BCA significantly decreased cellular reactive oxygen species (ROS) levels with a concomitant decrease in IL-1β mRNA levels upon LPS stimulation. However, in the BMM from Nrf2^−/− mice, the anthocyanin fractions were able to significantly decrease IL-1β mRNA despite the fact that ROS levels were not significantly affected. In conclusion, BBA, BKA and BCA exert their anti-inflammatory effects in macrophages, at least in part, by inhibiting nuclear translocation of NF-κB independent of the NRF2-mediated pathways.     

IFN-beta inhibits the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes upon direct cell-cell contact.

Tumour necrosis factor (TNF)-alpha and interleukin (IL-)1beta, essential players in the pathogenesis of immuno-inflammatory diseases, are strongly induced in monocytes by direct contact with stimulated T lymphocytes. The present study shows that the latter mechanism is inhibited by interferon (IFN)-beta. In co-cultures of autologous T lymphocytes and monocytes stimulated by phytohaemagglutinin (PHA), IFN-beta inhibited the production of TNF-alpha and IL-1beta by 88 and 98%, respectively, whereas the simultaneous production of IL-1 receptor antagonist (IL-1Ra), was enhanced two-fold. The latter effects of IFN-beta were independent of modulations in IFN-gamma, IL-4 and IL-10 production. When monocytes were activated by plasma membranes of stimulated T cells, IFN-beta slightly inhibited the production of TNF-alpha and IL-1beta, while enhancing 1.5-fold that of IL-1Ra. The latter effect correlated with the persistence of high steady-state levels of IL-1Ra mRNA after 24 h of activation. Membranes isolated from T lymphocytes that had been stimulated in the presence of IFN-beta displayed a 80% decrease in their capacity to induce the production of IL-1beta and TNF-alpha in monocytes, whereas IL-1Ra induction was decreased by only 32%. These results demonstrate that IFN-beta modulates contact-mediated activation of monocytes by acting on both T lymphocytes and monocytes, decreasing the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes and directly enhancing the production of IL-1Ra in the latter cells.     

Anti-inflammatory effects of hepatocyte growth factor: induction of interleukin-1 receptor antagonist

Hepatocyte growth factor (HGF) prevents liver failure in various animal models including endotoxin-induced acute liver failure. We were interested to find out whether human HGF exerts anti-inflammatory effects by modulation of cytokine synthesis. Therefore, human HepG2 cells were cultured with increasing concentrations of HGF. HGF dose-dependently upregulated the production of interleukin-1 receptor antagonist (IL-1Ra). Incubation of HepG2 cells with interleukin-1beta (IL-1beta) caused an increase in IL-1Ra levels, while interleukin-6 (IL-6) had no effect on IL-1Ra synthesis. Co-stimulation of HepG2 cells with HGF + IL-1beta resulted in a synergistic effect on IL-1Ra mRNA and protein expression. Stimulation of freshly isolated mouse hepatocytes from male C57 BL/6 mice with HGF increased IL-1Ra mRNA and protein synthesis dose-dependently. A co-stimulation with HGF and IL-1beta had a synergistic effect on IL-1Ra mRNA expression but only a partially additive effect on IL-1Ra protein synthesis. HGF-induced IL-1Ra production was significantly decreased by the mitogen-activated protein kinase (MAPK) inhibitor PD98059. Accordingly, HGF stimulation specifically increased MAPK-dependent signalling pathway (p42/44). In contrast, in preactivated PBMC mRNA expression and protein synthesis of IL-1Ra, interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-alpha) were unaffected after stimulation with HGF. In conclusion, our data suggest that HGF exerts anti-inflammatory effects by modulating the signal transduction cascade leading to increased expression of IL-1Ra, which might explain the protective and regenerative properties of this cytokine in animal models of liver failure.     

Effects of Dietary Manganese on Cu, Fe, Zn, Ca, Se, IL-1β, and IL-2 Changes of Immune Organs in Cocks

Manganese (Mn) is an essential trace element required for normal development and bodily function. However, little is known about the effect of excessive amounts of Mn in immune organs of poultry. The aim of this study was to investigate the effect of dietary Mn on the content of trace elements, such as copper (Cu), iron (Fe), zinc (Zn), calcium (Ca), and selenium (Se), and the mRNA level of IL-1β and IL-2 in immune organs (spleen, thymus, and bursa of Fabricius) and the content of IL-1β and IL-2 in serum of poultry. Fifty-day-old male Hyline cocks were fed either a commercial diet or a Mn-supplemented diet containing 600, 900, and 1,800 mg/kg. The immune organs were collected at 30, 60, and 90 days, respectively, and the content of trace elements and the mRNA level of IL-1β and IL-2 were examined; the serum were collected and the IL-1β and IL-2 contents detected. The results showed that Mn content in immune organs increased and Fe, Zn, and Ca contents decreased; however, Cu and Se contents showed no difference. IL-1β and IL-2 mRNA levels and IL-1β and IL-2 contents decreased. The present study demonstrates that excess exposure to Mn results in metal accumulations in immune organs. Manganism can disturb the balance of trace elements in immune organs and induce immune suppression in the molecular level; therefore, the immune function of cocks are also suppressed after manganism.