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Introduction: This study investigates the interactions between histaminergic system and glucocorticoid-induced leucin zipper (GILZ) in the inflammatory process and glucocorticoid modulation in lung fibrosis. Methods: Wild-type (WT) and GILZ Knock-Out (KO) mice were treated with bleomycin (0.05 IU) or saline, delivered by intra-tracheal injection. After surgery, mice received a continuous infusion of JNJ7777120 (JNJ, 2 mg/kg b.wt.) or vehicle for 21 days. Lung function was studied by measuring airway resistance to air insufflation through the analysis of pressure at airway opening (PAO). Lung samples were collected to evaluate the expression of histamine H4R, Anx-A1, and p65-NF-kB, the activity of myeloperoxidase (MPO), and the production of pro-inflammatory cytokines. Results: Airway fibrosis and remodeling were assessed by measuring TGF-β production and α-SMA deposition. JNJ reduces PAO in WT but not in GILZ KO mice (from 22 ± 1 mm to 15 ± 0.5 and from 24 ± 1.5 to 19 ± 0.5 respectively), MPO activity (from 204 ± 3.13 pmol/mg to 73.88 ± 2.63 in WT and from 221 ± 4.46 pmol/mg to 107 ± 5.54 in GILZ KO), the inflammatory response, TGF-β production, and α-SMA deposition in comparison to WT and GILZ KO vehicle groups. Conclusion: In conclusion, the role of H4R and GILZ in relation to glucocorticoids could pave the way for innovative therapies to counteract pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

Hind limb-suspended rats represent a sedentary-hyperinsulinemic model with a liver dyslipidemia mainly related to changes in sterol regulatory element-binding protein 1 (SREBP-1) and peroxisome proliferator-activated receptor-α (PPARα) expression and activity. To assess the effects of dietary fatty acids on hepatic lipid homeostasis, the hepatic expression and activity of PPARα, SREBP-1, and hepatocyte nuclear factor-4α (HNF-4α) were investigated in this animal model. In control and sedentary rats, diets enriched with saturated, monounsaturated, and polyunsaturated fatty acids (PUFA) enhanced the expression of the PPARα target genes carnitine palmitoyltransferase 1 and acyl-CoA oxidase, the highest effect being exerted by ω-3. The same diets reduced SREBP-1 mRNA and target lipogenic gene expression, as indicated by the reduction in fatty acid synthase and acetyl-CoA carboxylase mRNA content. Effects were greater in sedentary rat liver than in controls on the same diet. Only the ω-3 enriched diet decreased liver triglyceride content as well as plasma cholesterol and triglyceride levels in sedentary rats. This effect may be mainly related to the enhanced mitochondrial and peroxisomal β-oxidation genes expression. On the other hand, saturated fatty acid-enriched diet induced an increase in liver triglyceride content and enhanced plasma cholesterol and triglyceride levels, both in control and immobilized rats. This detrimental effect may be ascribed to the induced HNF-4α binding activity on ApoCIII promoter and to the enhanced ApoCIII mRNA levels both in control and in sedentary rat livers. In conclusion, we can speculate that dietary saturated fats, acting at apolipoprotein transcriptional level, may impact on the close relationship existing among high ApoCIII plasma level, dyslipidemia, and atherosclerosis. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) is a major cause of disability, its clinical outcome depending mostly on the extent of damage in which proapoptotic cytokines have a crucial function. In particular, the inducers of apoptosis belonging to TNF receptor superfamily and their respective ligands are upregulated after SCI. In this study, the function of the proapoptotic cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in SCI-induced damage was investigated in the mouse. SCI resulted in severe trauma, characterized by prominent inflammation-related damage and apoptosis. Immunostaining for TRAIL and its receptor DR5 was found in the white and gray matter of the perilesional area, as also confirmed by western blotting experiments. Immunoneutralization of TRAIL resulted in improved functional recovery, reduced apoptotic cell number, modulation of molecules involved in the inflammatory response (FasL, TNF-α, IL-1β, and MPO), and the corresponding signaling (caspase-8 and -3 activation, JNK phosphorylation, Bax, and Bcl-2 expression). As glucocorticoid-induced TNF receptor superfamily-related protein (GITR) activated by its ligand (GITRL) contributes to SCI-related inflammation, interactions between TRAIL and GITRL were investigated. SCI was associated with upregulated GITR and GITRL expression, a phenomenon prevented by anti-TRAIL treatment. Moreover, the expression of both TRAIL and DR5 was reduced in tissues from mice lacking the GITR gene (GITR−/−) in comparison with wild-type mice suggesting that TRAIL- and GITRL-activated pathways synergise in the development of SCI-related inflammatory damage. Characterization of new targets within such molecular systems may constitute a platform for innovative treatment of SCI. [ABSTRACT FROM AUTHOR]

Nerve growth factor (NGF) has an important role in regulating sympathetic neuron survival and target field innervation during development. Here we show that glucocorticoid-induced tumor necrosis factor receptor–related protein (GITR), a member of the TNF superfamily, and its ligand (GITRL) are co-expressed in mouse sympathetic neurons when their axons are innervating their targets under the influence of target-derived NGF. In culture, GITRL enhanced NGF-promoted neurite growth from neonatal sympathetic neurons, and preventing GITR-GITRL interaction in these neurons or knocking down GITR inhibited NGF-promoted neurite growth without affecting neuronal survival. Tnfrsf18−/− (Gitr) neonates have reduced sympathetic innervation density in vivo compared with Gitr+/+ littermates. GITR activation is required for the phosphorylation of extracellular signal–regulated kinases 1 and 2 by NGF that is necessary for neurite growth. Our results reveal a previously unknown signaling loop in developing sympathetic neurons that is crucial for NGF-dependent axon growth and target innervation. [ABSTRACT FROM AUTHOR]

Glucocorticoid-induced tumor necrosis factor receptor (GITR) on T cells and its natural ligand, GITRL, on accessory cells contribute to the control of immune homeostasis. Here we show that reverse signaling through GITRL after engagement by soluble GITR initiates the immunoregulatory pathway of tryptophan catabolism in mouse plasmacytoid dendritic cells, by means of noncanonical NF-κB–dependent induction of indoleamine 2,3-dioxygenase (IDO). The synthetic glucocorticoid dexamethasone administered in vivo activated IDO through the symmetric induction of GITR in CD4+ T cells and GITRL in plasmacytoid dendritic cells. The drug exerted IDO-dependent protection in a model of allergic airway inflammation. Modulation of tryptophan catabolism via the GITR-GITRL coreceptor system might represent an effective therapeutic target in immune regulation. Induction of IDO could be an important mechanism underlying the anti-inflammatory action of corticosteroids. [ABSTRACT FROM AUTHOR]

The exposure of phosphatidylserine toward the external surface of the membrane is a well-established event of programmed cell death. The possibility that an apoptotic stimulus influences the metabolism of this phospholipid could be relevant not only in relation to the previously mentioned event but also in relation to the capability of membrane phosphatidylserine to influence PKC activity. The present investigation demonstrates that treatment of mouse thymocytes with the apoptotic stimulus dexamethasone, enhances the incorporation of [3H]serine into phosphatidylserine. Cell treatment with dexamethasone also enhanced the activity of serine base exchange enzyme, assayed in thymocyte lysate. Both the effects were observed at periods of treatment preceding DNA fragmentation. The addition of unlabelled ethanolamine, together with [3H]serine to the medium containing dexamethasone-treated thymocytes lowered the radioactivity into phosphatidylserine. Serine base exchange enzyme activity was influenced by the procedure used to prepare thymocyte lysate and was lowered by the addition of fluoroaluminate, that is widely used as a G-protein activator. The increase of serine base exchange enzyme activity induced by dexamethasone treatment was observed independently by the procedure used to prepare cell lysate and by the presence or absence of fluoroaluminate. [ABSTRACT FROM AUTHOR]

T-cell receptor (TCR) is a multichain receptor in which the TCRζ subunit is important for membrane assembly and signal transduction. Four alternative splicings of the murine TCRζ gene locus have been previously described. We here describe a new alternative splicing of murine TCRζ gene, TCRκ, cloned by RT-PCR, that is encoded by exons 1-7, a portion of exon 9 and the whole exon 10 of TCRζ gene. The protein encoded by TCRκ mRNA is identical to that encoded by TCRκ mRNA, because the stop codon is present in the exon 9 before splicing with exon 10. RNAse protection assays carried out on total RNA from thymocytes indicate that TCRκ mRNA is 1 half with respect to TCRκ mRNA, suggesting that TCRκ mRNA contributes to determine the TCRκ protein levels. The 3′ untranslated region of TCRκ mRNA is different from that of TCRκ and this might lead to different t1/2 for each species in vivo. We also show that dexamethasone (DEX), a synthetic glucocorticoid hormone, increases the amount of TCRκ in the hybridoma T-cell line 3DO (about 5-fold increase), as indicated by reverse transcriptase-polymerase chain reaction (RT-PCR) and RNAse protection assays. This newly described effect of DEX may constitute a further molecular mechanism that contributes to its immunomodulating activity. [ABSTRACT FROM AUTHOR]

Glucocorticoid hormones (GCH) are anti-inflammatory and immunosuppressive agents that inhibit T-cell growth and activation. Since the T-cell receptor (TCR)/CD3 complex mediates T-lymphocyte activation, we studied the effect of in vitro dexamethasone (DEX), a synthetic GCH, on TCR/CD3 expression. DEX-treatment of a hybridoma T-cell line and normal un-transformed T-cell clones induced a decrease of the TCR/CD3 membrane expression after 4 days. After 4 weeks, TCR/CD3 was undetectable. However, the amount of mRNAs coding TCR/CD3 chains, including TCRα, TCRβ, CD3γ, CD3δ and CD3ε, as well as the amount of CD3ε protein, a major component of the complex, were unaltered. By contrast, a decrease of the mRNAs deriving from the TCRζ gene locus, as well as of the TCRζ protein which is responsible for the membrane expression of the TCR/CD3 complex, was induced. These data suggest that the down-modulation of TCR expression is due to the diminution of TCRζ gene products in DEX-treated cells. (Mol Cell Biochem 167: 135-144, 1997) [ABSTRACT FROM AUTHOR]

A single injection of αβ-interferon (αβ-IFN) (30 000 units/mouse), a major biological modifier of natural killer (NK) cytolytic activity, strongly stimulated NK activity in normal mice, as expected, while the same treatment did not statistically alter the NK response in cyclophosphamide (CY)-suppressed animals. We investigated the possibility of thymosin α cooperating with αβ-IFN in boosting NK activity in CY-suppressed animals. The results show that treatment with thymosin α (200 μg/kg) for 4 days, followed by a single injection of αβ-IFN 24 h before testing, strongly restored NK activity in CY-suppressed mice. Thymosin α was, moreover, able to accelerate the recovery rate of NK activity in bone marrow reconstituted murine chimeras. Taken together the data support the concept that the synergic effect between thymosin α and αβ-IFN could be the result of effects on differentiation of the NK lineage at different levels. [ABSTRACT FROM AUTHOR]

Psoriasis vulgaris is a chronic inflammatory skin disease affecting millions of people. Its pathophysiology is complex and involves a skin compartment with epidermal and immune cells which produce cytokines, e.g. belonging to the IL-23-Th17-cell axis. Glucocorticoids (GCs) are the most common therapeutics used in cutaneous inflammatory disorders and GC-induced leucine zipper (GILZ) has emerged as a mediator of GCs due to its anti-inflammatory actions, theoretically lacking GC side-effects. We evaluated whether GILZ may provide a better therapeutic index in comparison to GCs during the onset and progression of psoriasis by generating and characterizing a mouse model with generalized overexpression of this protein (GILZ-Tg mice) and the imiquimod (IMQ) psoriasis model. Unexpectedly, in GILZ-Tg mice, the severity of IMQ-induced psoriasis-like skin lesions as well as induction of cytokines commonly up-regulated in human psoriasis (Il-17, Il-22, Il-23, Il-6, S100a8/a9, and Stat3) was significantly more pronounced relative to GILZ-Wt mice. The increased susceptibility to IMQ-induced psoriasis of GILZ-Tg mice was significantly associated with skin-specific over-activation of TGF-β1-mediated signaling via SMAD2/3. Our findings demonstrate that GILZ may behave as pro-inflammatory protein in certain tissues and that, similar to prolonged GC therapy, GILZ as an alternative treatment for psoriasis may also have adverse effects. [ABSTRACT FROM AUTHOR]