IL-1β Challenge Research Articles

Conditional Knockout of IL-1R1 in Endothelial Cells Attenuates Seizures and Neurodegeneration via Inhibiting Neuroinflammation Mediated by Nrf2/HO-1/NLRP3 Signaling in Status Epilepticus Model

Studies on the bench and at bedside have demonstrated that the process of epileptogenesis is involved in neuroinflammatory responses. As the receptor of proinflammatory cytokine IL-1β, IL-1β type 1 receptor (IL-1R1) is reported to express abundantly in the endothelial cells in epileptic brains, which is deemed to be implicated in the epileptogenic process. However, whether and how endothelial IL-1R1 modulates neuroinflammatory responses in the pathological process of epileptic seizures and/or status epilepticus (SE) remains obscure. Here, we indicated endothelial IL-1R1 is involved in neuroinflammation, facilitating epilepsy progress via Nrf2/HO-1/NLRP3. In vitro, we observed upregulation of inflammatory cytokines in co-culture model under IL-1β challenge, as well as in BV2 cells after stimulation with conditional medium (CM) from IL-1β-stimulated bEnd.3 cells. In vivo, mice with conditional knockout of endothelial IL-1R1 (IL-1R1-CKO) were generated by hybrid IL-1R1flox/flox mice with Tek-Cre mice. IL-1R1-CKO reduced seizure susceptibility in kainic acid (KA)-induced SE model. In addition, IL-1R1-CKO KA mice exhibited lessened hippocampal neuroinflammation, mitigated neuronal damage, and decreased abnormal neurogenesis. In cognitive behavioral tests, IL-1R1-CKO KA mice presented improvement in learning and memory. Furthermore, we also indicated blockage of endothelial IL-1R1 downregulated the expressions of Nrf2/HO-1/NLRP3 pathway-related proteins. Nrf2-siRNA reversed the downregulation of HO-1, NLRP3, caspase-1, and IL-1β. These results demonstrated CKO of endothelial IL-1R1 reduces seizure susceptibility and attenuates SE-related neurobehavioral damage by suppressing hippocampal neuroinflammation via Nrf2/HO-1/NLRP3.

BLK positively regulates TLR/IL-1R signaling by catalyzing TOLLIP phosphorylation.

TLR/IL-1R signaling plays a critical role in sensing various harmful foreign pathogens and mounting efficient innate and adaptive immune responses, and it is tightly controlled by intracellular regulators at multiple levels. In particular, TOLLIP forms a constitutive complex with IRAK1 and sequesters it in the cytosol to maintain the kinase in an inactive conformation under unstimulated conditions. However, the underlying mechanisms by which IRAK1 dissociates from TOLLIP to activate TLR/IL-1R signaling remain obscure. Herein, we show that BLK positively regulates TLR/IL-1R-mediated inflammatory response. BLK-deficient mice produce less inflammatory cytokines and are more resistant to death upon IL-1β challenge. Mechanistically, BLK is preassociated with IL1R1 and IL1RAcP in resting cells. IL-1β stimulation induces heterodimerization of IL1R1 and IL1RAcP, which further triggers BLK autophosphorylation at Y309. Activated BLK directly phosphorylates TOLLIP at Y76/86/152 and further promotes TOLLIP dissociation from IRAK1, thereby facilitating TLR/IL-1R-mediated signal transduction. Overall, these findings highlight the importance of BLK as an active regulatory component in TLR/IL-1R signaling.

Sex-specific differences in T-cell immune dysregulation and aberrant response to inflammatory stimuli in offspring exposed to maternal chronic inflammation.

Maternal chronic inflammation (MI) can adversely affect offspring's immune development resulting in dysregulation of splenic T cells. Interleukin 1 beta (IL-1β) contributes to mediating inflammation in the placenta to induce fetal toxicity and cause long-term postnatal sequelae. In this study, we investigated how MI affects the T-cell immune development from the fetal to the neonatal period and how offspring responded to postnatal IL-1β challenge when exposed to an adverse intrauterine environment. We also extend these studies to examine the sex-specific differences. Time-pregnant CD1 dams were administrated with four consecutive injections of mouse recombinant Interleukin-1β (rIL-1β) or phosphate-buffered saline (PBS) from embryonic day (E)14 to E17. Pups were treated with rIL-1β or PBS at postnatal day (PND)11 (pre-weaning) or PND24 (post-weaning). Pups' splenic immune cells were isolated and then characterized using flow cytometry. At PND12, no differences were observed either in Ctrl or MI offspring. At PND25, we observed elevated amount of CD8+ T cells, descending CD4+ /CD8+ and Treg/Teff ratio in MI offspring. Pre-weaning rIL-1β administration did not affect T-cell subpopulation in Ctrl pups while post-weaning rIL-1β administration increased T cells and CD8+ T cells and decreased CD4+ /CD8+ and Treg/Teff ratio in Ctrl offspring. Furthermore, pre-weaning rIL-1β administration decreased the frequency of T cells and Treg/Teff ratio in MI pups while post-weaning rIL-1β administration increased Tregs and Treg/Teff in MI pups. Regarding sex-specific changes, we observed that at PND12, MI females exhibited higher CD4+ /CD8+ and Treg/Teff ratio than Ctrl females. At PND25, we observed elevated amount of CD8+ T cells, descending CD4+ /CD8+ and Treg/Teff ratio in MI Females, while MI males did not show any changes in T-cell population. Pre-weaning rIL-1β administration decreased T-cell frequency in both MI males and females and decreased Treg/Teff ratio only in MI females. Post-weaning rIL-1β administration increased Tregs and Treg/Teff ratio, and decreased CD4+ /CD8+ ratio in MI females. Prenatal-inflammation-exposed offspring exhibited dysfunctional T-cell immunity and regulatory immune responses to postnatal challenges, showing both sex-specific and age-dependent differences. It could be speculated from our results that experiencing environmental challenges or adverse stimuli during the vulnerable intrauterine period, such as maternal chronic inflammation, stress, preterm birth, and chronic infections, might induce fetal immune reprogramming and potentially cause long-term adverse immune consequences, such as a predisposition to allergic diseases, autoimmune diseases, asthma and pediatric mortality of unknown etiology.

Bio-orthogonal Click Chemistry Methods to Evaluate the Metabolism of Inflammatory Challenged Cartilage after Traumatic Overloading.

During traumatic joint injuries, impact overloading can cause mechanical damage to the cartilage. In the following inflammation phase, excessive inflammatory cytokines (e.g., interleukin-1β (IL-1β)) can act on chondrocytes, causing over-proliferation, apoptosis, and extracellular matrix (ECM) degradation that can lead to osteoarthritis. This study investigated the combined effects of traumatic overloading and IL-1β challenge on the metabolic activities of chondrocytes. Bovine cartilage explants underwent impact overloading followed by IL-1β exposure at a physiologically relevant dosage (1 ng/mL). New click chemistry-based methods were developed to visualize and quantify the proliferation of in situ chondrocytes in a nondestructive manner without the involvement of histological sectioning or antibodies. Click chemistry-based methods were also employed to measure the ECM synthesis and degradation in cartilage explants. As the click reactions are copper-free and bio-orthogonal, i.e., with negligible cellular toxicity, cartilage ECM was cultured and studied for 6 weeks. Traumatic overloading induced significant cell death, mainly in the superficial zone. The high number of dead cells reduced the overall proliferation of chondrocytes as well as the synthesis of glycosaminoglycan (GAG) and collagen contents, but overloading alone had no effects on ECM degradation. IL-1β challenge had little effect on cell viability, proliferation, or protein synthesis but induced over 40% GAG loss in 10 days and 61% collagen loss in 6 weeks. For the overloaded samples, IL-1β induced greater degrees of degradation, with 68% GAG loss in 10 days and 80% collagen loss in 6 weeks. The results imply a necessary immediate ease of inflammation after joint injuries when trauma damage on cartilage is present. The new click chemistry methods could benefit many cellular and tissue engineering studies, providing convenient and sensitive assays of metabolic activities of cells in native three-dimensional (3D) environments.

IL-27 regulates HIF-1α-mediated VEGFA response in macrophages of diabetic retinopathy patients and healthy individuals

Human macrophages produce vascular endothelial growth factor A (VEGFA) for angiogenesis in diabetic retinopathy (DR). The regulatory function of IL-27 on human macrophages is not well understood. In particular, the effect of IL-27 on VEGFA response in human macrophages has not been investigated. We find that IL-27 suppresses VEGFA mRNA expression as well as protein secretion by human macrophages. The synergistic action of purinergic signaling and activation of hypoxia-inducible factor 1 alpha (HIF-1α) induces VEGFA production in a positive feedback loop. IL-27 signaling in human macrophages disrupts this positive feedback loop thus suppresses VEGFA production. Blockade of IL-27 signaling with a JAK2 antagonist reverses this downregulatory effect on HIF-1α and partially blocks the inhibitory effect on VEGFA production. Lastly, DR patient macrophages have a higher propensity to produce VEGFA and this is amplified by an in vitro challenge with the pro-inflammatory cytokine IL-1β. IL-27 suppresses VEGFA production by DR patient macrophages even in the presence of IL-1β challenge indicating a potential therapeutic use of IL-27 in the clinic.

LEF1-mediated MMP13 gene expression is repressed by SIRT1 in human chondrocytes.

Reduced SIRT1 activity and levels during osteoarthritis (OA) promote gradual loss of cartilage. Loss of cartilage matrix is accompanied by an increase in matrix metalloproteinase (MMP) 13, partially because of enhanced LEF1 transcriptional activity. In this study, we assessed the role of SIRT1 in LEF1-mediated MMP13 gene expression in human OA chondrocytes. Results showed that MMP13 protein levels and enzymatic activity decreased significantly during SIRT1 overexpression or activation by resveratrol. Conversely, MMP13 gene expression was reduced in chondrocytes transfected with SIRT1 siRNA or treated with nicotinamide (NAM), a sirtuin inhibitor. Chondrocytes challenged with IL-1β, a cytokine involved in OA pathogenesis, enhanced LEF1 protein levels and gene expression, resulting in increased MMP13 gene expression; however, overexpression of SIRT1 during IL-1β challenge impeded LEF1 levels and MMP13 gene expression. Previous reports showed that LEF1 binds to the MMP13 promoter and transactivates its expression, but we observed that SIRT1 repressed LEF1 protein and mRNA expression, ultimately reducing LEF1 transcriptional activity, as judged by luciferase assay. Finally, mouse articular cartilage from Sirt1-/- presented increased LEF1 and MMP13 protein levels, similar to human OA cartilage. Thus, demonstrating for the first time that SIRT1 represses MMP13 in human OA chondrocytes, which appears to be mediated, at least in part, through repression of the transcription factor LEF1, a known modulator of MMP13 gene expression.-Elayyan, J., Lee, E.-J., Gabay, O., Smith, C. A., Qiq, O., Reich, E., Mobasheri, A., Henrotin, Y., Kimber, S. J., Dvir-Ginzberg, M. LEF1-mediated MMP13 gene expression is repressed by SIRT1 in human chondrocytes.

Sex differences in the effect of acute peripheral IL-1β administration on the brain and serum BDNF and VEGF expression in rats

The present study was designed to evaluate, for the first time, the potential sex differences in BDNF and VEGF systems under normal conditions and in response to IL-1β given ip. Peripheral overproduction of this cytokine mediates the pathophysiology of various acute neuroinflammatory states. Until now, the effect of IL-1β on VEGF expression in rat brain structures and its serum level has not been examined. In male and female rats, the BDNF and VEGF mRNA expression, and BDNF level were evaluated in the amygdala, hippocampus, hypothalamus and pituitary gland. The VEGF levels were determined in the pituitary. Serum BDNF and VEGF levels were also measured. The pituitary BDNF mRNA, and BDNF and VEGF levels were higher in females than in male rats whereas in males, the BDNF levels were higher in the other brain structures. The serum BDNF concentration was similar in both groups but VEGF levels were enhanced in females. Following IL-1β (50μg/kg ip.) administration, a higher serum IL-1β level was detected in females than in males. In male rats, IL-1β decreased BDNF mRNA in all the brain structures, except for the pituitary, and VEGF mRNA in the amygdala. In opposite, IL-1β challenge in females increased the pituitary VEGF mRNA and serum BDNF and VEGF levels. These results suggest that in females BDNF and VEGF may play a more important role in the pituitary function. In males, amygdala trophic system seems to be especially sensitive to the enhanced peripheral IL-1β production. Our findings point to the need to consider sex-related differences to be able to draw reliable conclusions about changes in BDNF and VEGF levels during inflammation.

Erratum to: Interleukin-1beta-induced reduction of tissue water diffusion in the juvenile rat brain on ADC MRI is not associated with 31P MRS-detectable energy failure

[This corrects the article DOI: 10.1186/s12950-016-0118-3.].

Interleukin-1beta-induced reduction of tissue water diffusion in the juvenile rat brain on ADC MRI is not associated with (31)P MRS-detectable energy failure.

BackgroundIt has long been known that an intrastriatal microinjection of the archetypal pro-inflammatory cytokine, interleukin-1beta (IL-1β), in juvenile rats induces a chronic reduction in the apparent diffusion coefficient (ADC) of tissue water on magnetic resonance imaging (MRI). Reduced ADC during acute cerebral ischaemia is an established indicator of metabolic failure whereas the cause of the IL-1β-induced reduction remains to be deciphered. Previously, it has been shown that IL-1β does not perturb the phosphorus (31P) magnetic resonance spectroscopy (MRS)-detectable energy status of an ex vivo preparation of rat brain parenchyma that is devoid of a functional vasculature component. However, brain energy status following an IL-1β challenge in vivo remains to be examined.MethodsThis study is the first longitudinal in vivo examination of the correlation of ADC MRI with localised 31P MRS signals obtained specifically from within the injected and non-injected striatum following IL-1β (1 ng/ul or 100 ng/ul) challenge, in real-time.ResultsDespite observing a chronic reduction in ADC at either dose of IL-1β challenge, energy compromise was not detected at any time point.ConclusionsThe IL-1β-induced effects pertaining to a functional vasculature such as leukocyte recruitment, blood–brain barrier (BBB) breakdown and blood flow changes are unlikely to impact on overall tissue energy status. Compared to classic ischaemia, there is dissociation between ADC and energy status within an IL-1β-induced lesion in vivo.

Effect of Aging on Adipose Tissue Inflammation in the Knee Joints of F344BN Rats.

The infrapatellar fat pad (IFP) secretes inflammatory mediators in osteoarthritic knees, but the effect of aging on IFP inflammation is unknown. We tested the hypothesis that aging increases basal and interleukin-1β (IL-1β)-stimulated IFP inflammation in 10-, 20-, and 30-month-old male F344BN F1-hybrid rats. IFPs were cultured ex vivo for 24 hours and treated ±1ng/mL IL-1β to simulate injury-induced inflammation. IFP inflammation was evaluated by measuring secreted cytokine concentrations and by quantitative expression of immunoregulatory and pro- and anti-adipogenic genes. With age, osteoarthritis pathology increased and IFP mass decreased. Although adipocyte size did not change with age, variation in adipocyte size was positively associated with synovial thickness independent of age whereas associations with cartilage damage were age dependent. In the absence of IL-1β, aging was associated with a significant increase in IFP secretion of tumor necrosis factor α by 67% and IL-13 by 35% and a reduction in the expression of immunoregulatory M2 macrophage genes. However, following an IL-1β challenge, adipogenesis markers decreased and pro- and anti-inflammatory cytokines increased independent of age. The lone exception was leptin, which decreased >70% with age. Thus, although aging promotes osteoarthritis risk by increasing basal inflammation, our findings also revealed a potentially protective effect of aging by decreasing IL-1β-stimulated leptin production.

Aucubin prevents interleukin-1 beta induced inflammation and cartilage matrix degradation via inhibition of NF-κB signaling pathway in rat articular chondrocytes.

Proinflammatory cytokine interleukin-1β (IL-1β) plays a crucial role in the pathogenesis of Osteoarthritis (OA) by stimulating several mediators contributed to cartilage degradation. Aucubin, a natural compound derived from plants which has been shown to possess diverse biological activities including anti-inflammatory property, may benefit the IL-1β stimulated chondrocytes. The present study was aimed to investigate the effects of Aucubin on IL-1β stimulated rat chondrocytes. Rat chondrocytes were cultured and pretreated with Aucubin (1, 10, 20, 50μM), and then stimulated with or without IL-1β (10ng/ml). Gene and protein expression of MMP-3, MMP-9, MMP-13, cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) was determined by real-time PCR and Western blotting respectively. Nitric oxide (NO) production was quantified by Griess reagent. Phosphorylation and nuclear translocation of p65 were detected by western blotting and immunofluorescence, respectively. We found that Aucubin significantly reversed the elevated gene and protein expression of MMP-3, MMP-9, MMP-13, iNOS, COX-2 and the production of NO induced by IL-1β challenge in rat chondrocytes. Furthermore, Aucubin was able to suppress the IL-1β-mediated phosphorylation and nuclear translocation of p65, indicating Aucubin may possibly act via the NF-κB signaling pathway. The present study proposes that Aucubin may be a potential therapeutic choice in the treatment of OA due to its anti-inflammatory and chondroprotective features.

Modeling and design of challenge tests: Inflammatory and metabolic biomarker study examples

Given the complexity of pharmacological challenge experiments, it is perhaps not surprising that design and analysis, and in turn interpretation and communication of results from a quantitative point of view, is often suboptimal. Here we report an inventory of common designs sampled from anti-inflammatory, respiratory and metabolic disease drug discovery studies, all of which are based on animal models of disease involving pharmacological and/or patho/physiological interaction challenges. The corresponding data are modeled and analyzed quantitatively, the merits of the respective approach discussed and inferences made with respect to future design improvements. Although our analysis is limited to these disease model examples, the challenge approach is generally applicable to the vast majority of pharmacological intervention studies.In the present five Case Studies results from pharmacodynamic effect models from different therapeutic areas were explored and analyzed according to five typical designs. Plasma exposures of test compounds were assayed by either liquid chromatography/mass spectrometry or ligand binding assays. To describe how drug intervention can regulate diverse processes, turnover models of test compound–challenger interaction, transduction processes, and biophase time courses were applied for biomarker response in eosinophil count, IL6 response, paw-swelling, TNFα response and glucose turnover in vivo. Case Study 1 shows results from intratracheal administration of Sephadex, which is a glucocorticoid-sensitive model of airway inflammation in rats. Eosinophils in bronchoalveolar fluid were obtained at different time points via destructive sampling and then regressed by the mixed-effects modeling. A biophase function of the Sephadex time course was inferred from the modeled eosinophil time courses. In Case Study 2, a mouse model showed that the time course of cytokine-induced IL1β challenge was altered with or without drug intervention. Anakinra reversed the IL1β induced cytokine IL6 response in a dose-dependent manner. This Case Study contained time courses of test compound (drug), challenger (IL1β) and cytokine response (IL6), which resulted in high parameter precision. Case Study 3 illustrates collagen-induced arthritis progression in the rat. Swelling scores (based on severity of hind paw swelling) were used to describe arthritis progression after the challenge and the inhibitory effect of two doses of an orally administered test compound. In Case Study 4, a cynomolgus monkey model for lipopolysaccharide LPS-induced TNFα synthesis and/or release was investigated. This model provides integrated information on pharmacokinetics and in vivo potency of the test compounds. Case Study 5 contains data from an oral glucose tolerance test in rats, where the challenger is the same as the pharmacodynamic response biomarker (glucose). It is therefore convenient to model the extra input of glucose simultaneously with baseline data and during intervention of a glucose-lowering compound at different dose levels.Typically time-series analyses of challenger- and biomarker-time data are necessary if an accurate and precise estimate of the pharmacodynamic properties of a test compound is sought. Erosion of data, resulting in the single-point assessment of drug action after a challenge test, should generally be avoided. This is particularly relevant for situations where one expects time-curve shifts, tolerance/rebound, impact of disease, or hormetic concentration–response relationships to occur.

Pigment Epithelium-Derived Factor (PEDF) Suppresses IL-1β-Mediated c-Jun N-Terminal Kinase (JNK) Activation to Improve Hepatocyte Insulin Signaling

Pigment epithelium-derived factor (PEDF) is an antiinflammatory protein that circulates at high levels in the metabolic syndrome. Metabolic studies of PEDF knockout (KO) mice were conducted to investigate the relationship between PEDF, inflammatory markers, and metabolic homeostasis. Male PEDF KO mice demonstrated a phenotype consisting of increased adiposity, glucose intolerance, and elevated serum levels of metabolites associated with the metabolic syndrome. Genome expression analysis revealed an increase in IL-1β signaling in the livers of PEDF KO mice that was accompanied by impaired IRS and Akt signaling. In human hepatocytes, PEDF blocked the effects of an IL-1β challenge by suppressing activation of the inflammatory mediator c-Jun N-terminal kinase while restoring Akt signaling. RNA interference of PEDF in human hepatocytes was permissive for c-Jun N-terminal kinase activation and decreased Akt signaling. A metabolomics profile identified elevated circulating levels of tricarboxyclic acid cycle intermediates including succinate, an inducer of IL-1β, in PEDF KO mice. Succinate-dependent IL-1β expression was blocked by PEDF in PEDF KO, but not wild-type hepatocytes. In vivo, PEDF restoration reduced hyperglycemia and improved hepatic insulin signaling in PEDF KO mice. These findings identify elevated PEDF as a homeostatic mechanism in the human metabolic syndrome.

The flow dependency of Tie2 expression in endotoxemia

Tie2 is predominantly expressed by endothelial cells and is involved in vascular integrity control during sepsis. Changes in Tie2 expression during sepsis development may contribute to microvascular dysfunction. Understanding the kinetics and molecular basis of these changes may assist in the development of therapeutic intervention to counteract microvascular dysfunction. To investigate the molecular mechanisms underlying the changes in Tie2 expression upon lipopolysaccharide (LPS) challenge. Studies were performed in LPS and pro-inflammatory cytokine challenged mice as well as in mice subjected to hemorrhagic shock, primary endothelial cells were used for in vitro experiments in static and flow conditions. Eight hours after LPS challenge, Tie2 mRNA loss was observed in all major organs, while loss of Tie2 protein was predominantly observed in lungs and kidneys, in the capillaries. A similar loss could be induced by secondary cytokines TNF-α and IL-1β. Ang2 protein administration did not affect Tie2 protein expression nor was Tie2 protein rescued in LPS-challenged Ang2-deficient mice, excluding a major role for Ang2 in Tie2 down regulation. In vitro, endothelial loss of Tie2 was observed upon lowering of shear stress, not upon LPS and TNF-α stimulation, suggesting that inflammation related haemodynamic changes play a major role in loss of Tie2 in vivo, as also hemorrhagic shock induced Tie2 mRNA loss. In vitro, this loss was partially counteracted by pre-incubation with a pharmacologically NF-кB inhibitor (BAY11-7082), an effect further substantiated in vivo by pre-treatment of mice with the NF-кB inhibitor prior to the inflammatory challenge. Microvascular bed specific loss of Tie2 mRNA and protein in vivo upon LPS, TNFα, IL-1β challenge, as well as in response to hemorrhagic shock, is likely an indirect effect caused by a change in endothelial shear stress. This loss of Tie2 mRNA, but not Tie2 protein, induced by TNFα exposure was shown to be controlled by NF-кB signaling. Drugs aiming at restoring vascular integrity in sepsis could focus on preventing the Tie2 loss.

Modulation of ezrin and E-cadherin expression by IL-1β and TGF-β1 in human trophoblasts

Objectives: The present study examines the effects of IL-1β and TGF-β1 in modulation of ezrin, E-cadherin, CD44 and β-catenin expression in human trophoblast cells which may lead to their altered cytoskeleton dynamics during cell-to-cell and cell-to-matrix interactions. Methods: Trophoblast (extravillous and villous) cells isolated and purified from early and term placentae and human choriocarcinoma cell line JEG-3 used in this study were challenged with either IL-1β or TGF-β1 (10 ng/ml) for 12 h following which RT-PCR was performed for ezrin, E-cadherin, CD44 and β-catenin. Immunolocalization of these proteins was carried out in the chorionic villi as well as in the cultured cells stimulated by the cytokines. Western Blot was also performed to study the regulation of ezrin and E-cadherin in primary extravillous, villous and term trophoblast by these cytokines. Scanning electron microscopy (SEM) and Matrigel Invasion Assay was used to study the effect of these cytokines on cellular morphology and invasion. Results: IL-1β induced a down regulation in the expression of ezrin, E-cadherin and β-catenin while upregulation of CD44 message in both primary trophoblast and JEG-3 cells. On the contrary, TGF-β1 exhibited just an opposite effect, i.e. up regulation of ezrin, E-cadherin, β-catenin, and down regulation of CD44. These observations were further corroborated with the immunolocalization findings of the above proteins in first trimester and term villous tissue, the former having predominance of IL-1β and the latter of TGF-β1 [Am. J. Reprod. Immunol. 48 (2002) 210]. Cellular morphology as observed through SEM revealed an enhanced cell-to-matrix adhesion with poor cell–cell interaction following IL-1β challenge and a strong intercellular adhesion with weak cell-to-matrix interaction in presence of TGF-β1. Crystal violet staining and Matrigel invasion revealed a higher invasion index following IL-1β challenge and a low invasion index following TGF-β1 challenge. Conclusion: IL-1β mediated increased cell-to-matrix interaction with reduced cell-to-cell adhesion along with reduced ezrin and E-cadherin expression is associated with enhanced invasiveness while TGF-β1 mediated up regulation of cell-to-cell adhesion with reduced cell-to-matrix interaction along with an increased ezrin and E-cadherin expression, is associated with reduced invasiveness, along with an altered cellular morphology. These facts therefore indicate the possible role of the two cytokines during cell motility and invasion through alteration of cell–matrix and cell–cell interaction.

Behavioral changes in rats after acute, chronic and repeated administration of Interleukin-1beta: relevance for affective disorders

Background: Acute, peripheral and central administration of recombinant rat interleukin-1β (IL-1β) has been shown to decrease social exploration and locomotor activity and to induce alterations in brain biogenic amines in rats. The aims of this study were to examine whether acute, repeated and chronic administration of IL-1β to rats may interfere with shuttle box escape learning, a model for anxiety- and depression-like behavior. Methods: Sixty-four adult male viral-free Sprague–Dawley rats (200–300 g weight) housed in groups of four at 25 °C with a 12:12 light:dark cycle were used in the experiments. They were divided into 8 groups, i.e. 4 control and 4 experimental. The latter were divided into an acute group receiving a single intra-peritoneally (I.P.) challenge of IL-1β (tested at the shuttle box 1 and 24 h later); a chronic group with daily I.P. injections of IL-1β for 7 days (tested at the shuttle box 1 h later); and a group with repeated administration, i.e. one I.P. injection on the first day and a second challenge on the seventh day (tested at the shuttle box 1 h later). The control animals followed the same injecting and testing schedule but were treated I.P. with saline. Results: The acute group treated with one IL-1β challenge and tested 1 ( P=0.001) and 24 h ( P=0.002) later showed significant time elongations in the escape trials. The animals treated chronically with IL-1β for seven consecutive days showed a significant increase in the latency at the escape trials ( P=0.0001). Repeated administration of IL-1β on the first day and a second on the seventh day did not significantly alter the time elongation in the escape trial. Discussion: Acute and chronic administration of IL-1β significantly increase the latency of escape to a foot shock, whereas repeated IL-1β administration does not induce a sensitization of these behavioral responses.