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Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain, bloating, and disturbed bowel habit, symptoms that impact the quality of life of sufferers. The pathophysiological changes underlying this multifactorial condition are complex and include increased sensitivity to luminal and mucosal factors, resulting in altered colonic transit and visceral pain. Moreover, dysfunctional communication in the bidirectional signaling axis between the brain and the gut, which involves efferent and afferent branches of the peripheral nervous system, circulating endocrine hormones, and local paracrine and neurocrine factors, including immune and perhaps even microbial signaling molecules, has a role to play in this disorder. This minireview will examine recent advances in our understanding of the pathophysiology of IBS and assess how cross talk between hormones, immune, and microbe-derived factors and their neuromodulatory effects on peripheral nerves may underlie IBS symptomatology. [ABSTRACT FROM AUTHOR]

Although the majority of patients with asthma are well controlled by inhaled glucocorticoids (GCs), patients with severe asthma are poorly responsive to GCs. This latter group is responsible for a disproportionate share of health care costs associated with asthma. Recent studies in immune cells have incriminated interferon (IFN-γ) as a possible trigger of GC insensitivity in severe asthma; however, little is known about the role of IFN-γ in modulating GC effects in other clinically relevant nonimmune cells, such as airway epithelial cells. We hypothesized that IFN-γ-induced JAK/STAT-associated signaling pathways in airway epithelial cells are insensitive to GCs and that strategies aimed at inhibiting JAK/STAT pathways can restore steroid responsiveness. Using Western blot analysis we found that all steps of the IFN-γ-induced JAK/STAT signaling pathway were indeed GC insensitive. Transfection of cells with reporter plasmid showed IFN- γ-induced STAT1-dependent gene transcription to be also GC insensitive. Interestingly, real-time PCR analysis showed that IFN-γ- inducible genes (IIGs) were differentially affected by GC, with CXCL10 being GC sensitive and CXCL11 and IFIT2 being GC insensitive. Further investigation showed that the differential sensitivity of IIGs to GC was due to their variable dependency to JAK/STAT vs. NF-κB signaling pathways with GC-sensitive IIGs being more NF-κB dependent and GC-insensitive IIGs being more JAK/STAT dependent. Importantly, transfection of cells with siRNASTAT1 was able to restore steroid responsiveness of GC-insensitive IIGs. Taken together, our results show the insensitivity of IFN-γ- induced JAK/STAT signaling pathways to GC effects in epithelial cells and also suggest that targeting STAT1 could restore GC responsiveness in patients with severe asthma. [ABSTRACT FROM AUTHOR]

Junglee NA, Di Felice U, Dolci A, Fortes MB, Jibani MM, Lemmey AB, Walsh NP, Macdonald JH. Exercising in a hot environment with muscle damage: effects on acute kidney injury biomarkers and kidney function. Am J Physiol Renal Physiol 305: F813-F820, 2013. First published July 3, 2013; doi:10.1152/ajprenal.00091.2013.--Unaccustomed strenuous physical exertion in hot environments can result in heat stroke and acute kidney injury (AKI). Both exercise-induced muscle damage and AKI are associated with the release of interleukin- 6, but whether muscle damage causes AKI in the heat is unknown. We hypothesized that muscle-damaging exercise, before exercise in the heat, would increase kidney stress. Ten healthy euhydrated men underwent a randomized, crossover trial involving both a 60-min downhill muscle-damaging run (exercise-induced muscle damage; EIMD), and an exercise intensity-matched non-muscle-damaging flat run (CON), in random order separated by 2 wk. Both treatments were followed by heat stress elicited by a 40-min run at 33°C. Urine and blood were sampled at baseline, after treatment, and after subjects ran in the heat. By design, EIMD induced higher plasma creatine kinase and interleukin-6 than CON. EIMD elevated kidney injury biomarkers (e.g., urinary neutrophil gelatinase-associated lipocalin (NGAL) after a run in the heat: EIMD-CON, mean difference [95% CI]: 12 [5, 19] ng/ml) and reduced kidney function (e.g., plasma creatinine after a run in the heat: EIMD-CON, mean difference [95% CI]: 0.2 [0.1, 0.3] mg/dl), where CI is the confidence interval. Plasma interleukin-6 was positively correlated with plasma NGAL (r 0.9, P 0.001). Moreover, following EIMD, 5 of 10 participants met AKIN criteria for AKI. Thus for the first time we demonstrate that muscle-damaging exercise before running in the heat results in a greater inflammatory state and kidney stress compared with non-muscle-damaging exercise. Muscle damage should therefore be considered a risk factor for AKI when performing exercise in hot environments. [ABSTRACT FROM AUTHOR]

Most melanoma cells are characterized by the V600E mutation in B-Raf kinase. This mutation leads to increased expression of interleukin (CXCL8), which plays a key role in cell growth and angiogenesis. Thus CXCL8 appears to be an interesting therapeutic target. Hence, we performed vaccination of mice with GST-CXCL8, which results in a reduced incidence of syngenic B16 melanoma cell xenograft tumors. We next addressed the molecular mechanisms responsible for aberrant CXCL8 expression in melanoma. The CXCL8 mRNA contains multiples AU-rich sequences (AREs) that modulate mRNA stability through the binding of tristetraprolin (TTP). Melanoma cell lines express very low TTP levels. We therefore hypothesized that the very low endogenous levels of TTP present in different melanoma cell lines might be responsible for the relative stability of CXCL8 mRNAs. We show that TTP is actively degraded by the proteasome and that extracellular-regulated kinase inhibition results in TTP accumulation. Conditional expression of TTP in A375 melanoma cells leads to CXCL8 mRNA destabilization via its 3' untranslated regions (3′-UTR), and TTP overexpression reduces its production. In contrast, downregulation of TTP by short hairpin RNA results in upregulation of CXCL8 mRNA. Maintaining high TTP levels in melanoma cells decreases cell proliferation and autophagy and induces apoptosis. Sorafenib, a therapeutic agent targeting Raf kinases, decreases CXCL8 expression in melanoma cells through reexpression of TTP. We conclude that loss of TTP represents a key event in the establishment of melanomas through constitutive expression of CXCL8, which constitutes a potent therapeutic target. [ABSTRACT FROM AUTHOR]

Physiological changes, elicited in animal immune tissues by exposure to pathogens, may be studied using functional genomics approaches. We created and characterized reciprocal suppression subtractive hybridization (SSH) cDNA libraries to identify differentially expressed genes in spleen and head kidney tissues of Atlantic cod (Gadus morhua) challenged with intraperitoneal injections of formalin-killed, atypical Aeromonas salmonicida. Of 4,154 ESTs from four cDNA libraries, 10 genes with immune-relevant functional annotations were selected for QPCR studies using individual fish templates to assess biological variability. Genes confirmed by QPCR as upregulated by A. salmonicida included interleukin-1β, interleukin-8, a small inducible cytokine, interferon regulatory factor 1 (IRF1), ferritin heavy subunit, cathelicidin, and hepcidin. This study is the first large-scale discovery of bacteria-responsive genes in cod and the first to demonstrate upregulation of IRF1 in fish immune tissues as a result of bacterial antigen stimulation. Given the importance of IRF1 in vertebrate immune responses to viral and bacterial pathogens, the full-length cDNA sequence of Atlantic cod IRF1 was obtained and compared with putative orthologous sequences from other organisms. Functional annotations of assembled SSH library ESTs showed that bacterial antigen stimulation caused changes in many biological processes including chemotaxis, regulation of apoptosis, antimicrobial peptide production, and iron homeostasis. Moreover, differences in spleen and head kidney gene expression responses to the bacterial antigens pointed to a potential role for the cod spleen in blood-borne pathogen clearance. Our data show that Atlantic cod immune tissue responses to bacterial antigens are similar to those seen in other fish species and higher vertebrates. [ABSTRACT FROM AUTHOR]

Oncostatin M pathway plays arnajor role in the renal acute phase response. Am J Physiol Renal Physiol 296: F875-F883,. 2009. First published January 21, 2009; doi: 10.11 52/ajprenal.90633.2008.-The acute phase response is traditionally characterized by hepatic synthesis of proteins as an inflammatory response to injury, with interleukin-6 (IL-6) being the key mediator. In contrast, microarray studies in human renal transplant implantation biopsies indicate a strong acute phase response in the deceased donor kidney, associated with a significant upregulation of oncostatin M receptor 3 (OSMR). The aim of this study was to determine whether the kidney can generate a strong acute phase response, mediated by the OSM/OSMR gateway. Genes associated with the IL-6 cytokine family and acute phase reactants were analyzed by real-time RT-PCR in four groups of human biopsies spanning a spectrum of renal injury. OSM, OSMR, and fibrinogen 3 (FGB) were progressively more highly expressed from prenephrectomy, living donor, deceased donor, to discarded donor kidneys, suggesting correlation with severity of injury and local renal synthesis. Acute phase response gene expression was analyzed in human proximal tubular cells in culture in response to OSM. OSM induced a significant increase in expression of FGB, OSMR, serpin peptidase inhibitor Al, IL-6, and lipopolysaccharide binding protein, and a decrease in IL-6R. These changes were largely attenuated by coincubation with an OSMR blocking antibody, indicating the OSM effect was mediated through OSMR. OSM also resulted in a significantly altered expression of acute phase genes compared with IL-6 or leukemia inhibitory factor, suggesting that OSM is the predominant cytokine mediating the renal tubular acute phase response. In conclusion, the renal parenchyma is capable of generating a strong acute phase response, likely mediated via OSM/OSMR. [ABSTRACT FROM AUTHOR]

In this study, we examined whether IL-18 plays a role in lung inflammation following alcohol (EtOH) and burn injury. Male rats (~250 g) were gavaged with EtOH to achieve a blood EtOH level of ~100 mg/dl before burn or sham injury (~12.5% total body surface area). Immediately after injury, rats were treated with vehicle, caspase-1 inhibitor AC-YVAD-CHO to block IL-18 production or with IL-18 neutralizing anti-IL-18 antibodies. In another group, rats were treated with anti-neutrophil antiserum ~16 h before injury to deplete neutrophils. On day 1 after injury, lung tissue IL-18, neutrophil chemokines (CINC-1/CINC-3), ICAM-1, neutrophil infiltration, MPO activity, and water content (i.e., edema) were significantly increased in rats receiving a combined insult of EtOH and burn injury compared with rats receiving either EtOH intoxication or burn injury alone. Treatment of rats with caspase-1 inhibitor prevented the increase in lung tissue lL-18, CINC-1, CINC-3, ICAM-1, MPO activity, and edema following EtOH and burn injury. The increase in lung IL-18, MPO, and edema was also prevented in rats treated with anti-IL-18 antibodies. Furthermore, administration of anti-neutrophil antiserum also attenuated the increase in lung MPO activity and edema, but did not prevent the increase in IL-18 levels following EtOH and burn injury. These findings suggest that acute EtOH intoxication before burn injury upregulates IL-18, which in turn contributes to increased neutrophil infiltration. Furthermore, the presence of neutrophils appears to be critical for IL-18-meditaed increased lung tissue edema following a combined insult of EtOH and burn injury. [ABSTRACT FROM AUTHOR]

Familial periodic fever syndromes, otherwise known as hereditary autoinflammatory syndromes, are inherited disorders characterized by recurrent episodes of fever and inflammation. The general hypothesis is that the innate immune response in these patients is wrongly tuned, being either too sensitive to very minor stimuli or turned off too late. The genetic background of the major familial periodic fever syndromes has been unraveled, and through research into the pathophysiology, a clearer picture of the innate immune system is emerging. After an introduction on fever, interleukin-1β and inflammasomes, which are involved in the majority of these diseases, this manuscript offers a detailed review of the pathophysiology of the cryopyrin-associated periodic syndromes, familial Mediterranean fever, the syndrome of pyogenic arthritis, pyoderma gangrenosum and acne, Blau syndrome, TNF-receptor-associated periodic syndrome and hyper-IgD and periodic fever syndrome. Despite recent major advances, there are still many questions to be answered regarding the pathogenesis of these disorders. [ABSTRACT FROM AUTHOR]

IL-22 is produced by activated T cells and signals through a receptor complex consisting of IL-22R1 and IL-10R2. The aim of this study was to analyze IL-22 receptor expression, signal transduction, and specific biological functions of this cytokine system in intestinal epithelial cells (IEC). Expression studies were performed by RT-PCR. Signal transduction was analyzed by Western blot experiments, cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and Fas-induced apoptosis by flow cytometry. IEC migration was studied in wounding assays. The IEC lines Caco-2, DLD-1, SW480, HCT116, and HT-29 express both IL-22 receptor subunits IL-22R1 and IL-10R2. Stimulation with TNF-α, IL-1β, and LPS significantly upregulated IL-22R1 without affecting IL-10R2 mRNA expression. IL-22 binding to its receptor complex activates STAT1/3, Akt, ERK1/2, and SAPK/JNK MAP kinases. IL-22 significantly increased cell proliferation (P = 0.002) and phosphatidylinsitol 3-kinase-dependent IEC cell migration (P < 0.00001) as well as mRNA expression of TNF-α, IL-8, and human β-defensin-2. IL-22 had no effect on Fas-induced apoptosis. IL-22 mRNA expression was increased in inflamed colonic lesions of patients with Crohn's disease and correlated highly with the IL-8 expression in these lesions (r = 0.840). Moreover, IL-22 expression was increased in murine dextran sulfate sodium-induced colitis. IEC express functional receptors for IL-22, which increases the expression of proinflammatory cytokines and promotes the innate immune response by increased defensin expression. Moreover, our data indicate intestinal barrier functions for this cytokine-promoting IEC migration, which suggests an important function in intestinal inflammation and wound healing. IL-22 is increased in active Crohn's disease and promotes proinflammatory gene expression and IEC migration. [ABSTRACT FROM AUTHOR]

We recently reported an involvement of ANG II and the ANG II type 1 (AT1) receptor in the hepatic expression of IL-1β induced in dehydrated rats by LPS. Here, we first confirmed that ANG II and AT1 receptors contribute to the LPS-induced increase in the splenic concentration of IL-1β in dehydrated rats. We then investigated whether ANG II contributes to IL-1 production through a modulating effect on the activation of proinflammatory transcription factors (NF-κB and AP-1) that is induced in the dehydrated rat's liver and spleen by intravenous injection of LPS. Surprisingly, LPS markedly increased the hepatic activation of NF-κB, an effect that was significantly enhanced (rather than reduced) by pretreatment with an ANG-converting-enzyme (ACE) inhibitor or AT1-receptor antagonist. Furthermore, the same ACE inhibitor and AT1-receptor antagonist each increased the resting NF-κB activity in the liver and spleen, although they had no effect on the LPS-induced splenic expression of NF-κB. Both hepatic and splenic AP-I expressions were enhanced by LPS. This response was significantly augmented by pretreatment with the AT1-receptor antagonist (but not with the ACE inhibitor) in the spleen, while in the liver, neither drug had any effect. These results suggest that the endogenous ANG II or AT1 receptor suppresses the activation of hepatic or splenic transcription factors in dehydrated rats given LPS. Our results seem not to support the idea that NF-κB and AP-1 play key roles in the ANG H-induced enhancement of the production of proinflammatory cytokines that is induced by LPS in dehydrated rats. [ABSTRACT FROM AUTHOR]

Fever is a common, centrally elicited sign of inflammatory and infectious processes and is known to be induced by the action of PGE2 on its specific receptors in the thermogenic region of the hypothalamus. In the present work, using genetically modified mice, we examined the role of the inducible terminal PGE2-synthesizing enzyme microsomal prostaglandin E synthase-1 (mPGES-1) for the generation of immune-elicited fever. Animals with a deletion of the Ptges gene, which encodes mPGES-1, or their wild-type littermates were given either a subcutaneous injection of turpentine—a model for aseptic cytokine-induced pyresis—or an intraperitoneal injection of interleukin-1 β. While both procedures resulted in typical febrile responses in wild-type animals, these responses were strongly impaired in the mPGES-1 mutant mice. In contrast, both genotypes showed psychogenic stress-induced hyperthermia and displayed normal diurnal temperature variations. Both wild-type and mPGES-1 mutant mice also showed strongly reduced motor activity following turpentine injection. Taken together with previous observations on mPGES-1 induction in the brain vasculature during various inflammatory conditions and its role in endotoxin-induced pyresis, the present findings indicate that central PGE2 synthesis by mPGES-1 is a general and critical mechanism for fever during infectious and inflammatory conditions that is distinct from the mechanism(s) underlying the circadian temperature regulation and stress-induced hyperthermia, as well as the inflammation-induced activity depression. [ABSTRACT FROM AUTHOR]

A prolonged depression of cardiovascular function occurs in males after trauma-hemorrhagic shock (T-H). Although a correlation between increased circulatory IL-6 levels and poor outcome has been reported after T-H, it remains unknown whether T-H increases IL-6 levels locally in cardiomyocytes and whether there is a correlation between altered cardiac function and local IL-6 production after T-H. T-H was induced in normal, castrated (2 wk before T-H), and 17β-estradiol (E2)-treated (0.5 mg sc, 1 wk before T-H) adult male rats. At 2 h after T-H or sham operation, cardiac output, heart rate, mean arterial pressure, positive and negative first derivative of pressure (± dP/dt), stroke volume, and total peripheral resistance were determined. Cardiomyocytes were isolated and divided into two parts: one was used for measurements of intracellular IL-6 levels using fluorescein-activated cell sorting, and the other was used to isolate RNA to determine IL-6 gene expression by quantitative real-time PCR. In addition, cardiac IL-6 protein levels were measured in freshly isolated hearts by Western blotting. Cardiac output, stroke volume, +dP/dt, -dP/dt, and total peripheral resistance were markedly altered after T-H. These parameters, except -dP/dt, improved significantly in the castrated group; however, all these parameters were restored in E2-treated males. Cardiomyocyte IL-6 mRNA expression and intra- cellular IL-6 production increased after T-H. Cardiac IL-6 protein levels increased after T-H in freshly isolated heart. Castration and E2 treatment attenuated cardiomyocyte intracellular IL-6 levels and car- diac IL-6 protein levels after T-H; however, only E2 treatment attenuated cardiomyocyte IL-6 gene expression. Thus there is an inverse correlation between cardiomyocyte IL-6 levels and cardiac function after T-H. The salutary effects of E2 on cardiac function after T-H may be due in part to decreased IL-6 synthesis in cardiomyocytes. [ABSTRACT FROM AUTHOR]

We examined the effects of interleukin-1β (IL-1β) treatment on the distribution and degradation of lamin B in the nuclear fraction from insulin-secreting RINm5F cells. Western blot analysis indicated that IL-1β treatment caused significant alterations in the redistribution of lamin B, specifically between the Triton X-100-soluble (membrane) and -insoluble (matrix) fractions of the nucleus. IL-1β treatment also increased the lamin carboxymethyltransferase activity and the relative abundance of the carboxymethylated lamin in the nuclear fraction. A significant increase in the relative abundance of lamin B degradation products was also observed in the nuclear fraction from the IL-1β-treated cells. These findings are compatible with a measurable increase in the lamin-degrading caspase-6 activity in IL-1βtreated ceils. Confocal microscopic observation of IL-1β-treated cells suggested a significant dissociation of lamin B from the nuclear lamina and its subsequent association with the DNA-rich elements within the nucleus. NG-monomethyl-L-arginine, a known inhibitor of inducible nitric oxide synthetase (iNOS), markedly inhibited IL-1βinduced iNOS gene expression, NO release, caspase-3 and caspase-6 activation, lamin B degradation, and loss of metabolic cell viability, indicating that the observed IL-1β-induced effects on nuclear lamin B involve the intermediacy of NO. Together, our data support the hypothesis that IL-1β treatment results in significant increase in the carboxymethylation of lamin B, which would place lamin B in a strategic location for its degradation mediated by caspases. This could possibly lead to dissolution of the nuclear envelope, culminating in the demise of the effete β-cell. [ABSTRACT FROM AUTHOR]

Intestinal mucosal cells and invading leukocytes produce inappropriate levels of cytokines and chemokines in human colitis. However, smooth muscle cells of the airway and vasculature also synthesize cytokines and chemokines. To determine whether human colonic myocytes can synthesize proinflammatory mediators, strips of circular smooth muscle and smooth muscle cells were isolated from human colon. Myocytes and muscle strips were stimulated with 10 ng/ml of IL-1β, TNF-α, and IFN-γ, respectively. Expression of mRNA for IL-1β, IL-6, IL-8, and cyclooxygenase-2 (COX-2) was induced within 2 h and continued to increase for 8-12 h. Regulated on activation, normal T cell-expressed and -secreted (RANTES) mRNA expression was slower, appearing at 8 h and increasing linearly through 20 h. Expression of all five mRNAs was inhibited by 0.1 µM MG-132, a proteosome inhibitor that blocks NF-κB activation. Expression of IL-1β, IL-6, IL-8, and COX-2 mRNA was reduced by 30 µM PP1, an Src family tyrosine kinase inhibitor, and by 25 µM SB-203580, a p38 MAPK inhibitor. MAPK/extracellular regulated kinase-1 inhibitor PD-98059 (25 µM) was much less effective. In conclusion, human colonic smooth muscle cells can synthesize and secrete interleukins (IL-1β and IL-6) and chemokines (IL-8 and RANTES) and upregulate expression of COX-2. Regulation of cytokine, chemokine, and COX-2 mRNA depends on multiple signaling pathways, including Src-family kinases, extracellular regulated kinase, p38 MAPKs, and NF-κB. SB-203580 was a consistent, efficacious inhibitor of inflammatory gene expression, suggesting an important role of p38 MAPK in synthetic functions of human colonic smooth muscle. [ABSTRACT FROM AUTHOR]

Exposure to airborne particulate matter (PM) is a world-wide health problem mainly because it produces adverse cardiovascular and respiratory effects that frequently result in morbidity. Despite many years of epidemiological and basic research, the mechanisms underlying PM toxicity remain largely unknown. To understand some of these mechanisms, we measured PM-induced apoptosis and necrosis in normal human airway epithelial cells and sensory neurons from both wild-type mice and mice lacking TRPV1 receptors using Alexa Fluor 488-conjugated annexin V and propidium iodide labeling, respectively. Exposure of environmental PMs containing residual oil fly ash and ash from Mount St. Helens was found to induce apoptosis, but not necrosis, as a consequence of sustained calcium influx through TRPV1 receptors. Apoptosis was completely prevented by inhibiting TRPV1 receptors with capsazepine or by removing extracellular calcium or in sensory neurons from TRPV1(-/-) mice. Binding of either one of the PMs to the cell membrane induced a capsazepine-sensitive increase in cAMP. PM-induced apoptosis was augmented upon the inhibition of PKA. PKA inhibition on its own also induced apoptosis, thereby suggesting that this pathway may be endogenously protective against apoptosis. In summary, it was found that inhibiting TRPV1 receptors prevents PM-induced apoptosis, thereby providing a potential mechanism to reduce their toxicity. [ABSTRACT FROM AUTHOR]

Examines the influence of resistive exercise training and hormone status on messenger RNA expression of toll-like receptor 4, CD14, interleukin-(IL)1beta, IL-6 and tumor necrosis factor-alpha. Acclimation and resistive exercise training; Cytokine stimulation; Importance of toll-like receptor in mediating both the innate and cytokine-activated, cell-mediated immune systems.

Investigates the effect of interleukin-13 (IL-13) on ion transport of human bronchial epithelial cells. Association of IL-13 with onset of asthma, rhinitis and sinusitis; Inducement of apical calcium activated anion conductance through IL-13; Conversion of human bronchial epithelium into secretory phenotype.

Presents a study which examined whether cells transfected with early region 1A enhanced interleukin-8 production in response to particulate matter[sub 10]. Materials and methods; Results and discussion.

Presents a study which assessed interleukin mice for cytokine production during pregnancy. Materials and methods; Results; Discussion.