Glucocorticoids have been exploited therapeutically for more than six decades through the use of synthetic glucocorticoids as anti-inflammatory agents, and are still used in as many as 50% of patients suffering from inflammatory diseases such as rheumatoid arthritis (RA). Better understanding of the mechanisms of action of glucocorticoids could enable the development of therapies that dissociate the broad-spectrum benefits of glucocorticoids from their adverse metabolic effects. The glucocorticoid-induced leucine zipper protein (GILZ; also known as TSC22 domain family protein 3) is a glucocorticoid-responsive molecule whose interactions with signal transduction pathways, many of which are operative in RA and other inflammatory diseases, suggest that it is a key endogenous regulator of the immune response. The overlap between the observed effects of GILZ on the immune system and those of glucocorticoids strongly suggest GILZ as a critical mediator of the therapeutic effects of glucocorticoids. Observations of the immunomodulatory effects of GILZ in human RA synovial cells, and in an in vivo model of RA, support the hypothesis that GILZ is a key glucocorticoid-induced regulator of inflammation in RA. Moreover, evidence that the effect of GILZ on bone loss might be in contrast to those of glucocorticoids suggests manipulation of GILZ as a potential means of dissociating the beneficial anti-inflammatory effects of glucocorticoids from their negative metabolic repercussions.
"Recognized contributing mechanisms to the anti-inflammatory actions of GCs include the GC-induced anti-inflammatory proteins MAPK phosphatase-1 (MKP1, or DUSP1) and GC-induced leucine zipper (GILZ) (Clark, 2007; Beaulieu & Morand, 2011; Clark & Belvisi, 2012; Newton, 2014; Vandevyver et al., 2013). Previous studies have shown that the anti-inflammatory GC effects (including attenuation of proinflammatory cytokine interleukin (IL)-6 expression, and induction of anti-inflammatory protein MKP-1) are dependent on ANX-A1 (Yang et al., 2006). "
"The effects of the GC/GR complex depend on a combination of several effects. These include (i) transrepression, whereby the GC-GR complex tethers to pro-inflammatory transcription factors such as NF-κB and AP-1, constraining their activity; (ii) cis-repression, whereby the GC-GR complex binds directly to DNA and exerts inhibitory effects on gene transcription; and (iii) transactivation, whereby a GC-GR dimer acts as a bona fides transcription factor and activates gene transcription (McKay and Cidlowski, 1999; De Bosscher et al., 2003; Barnes, 2006; Beaulieu and Morand, 2011). Despite their beneficial effects, adverse effects of GC treatment have been noted since the beginning of their usage, because the amount of GCs required therapeutically to inhibit the immune system is in excess of metabolic homeostatic requirements. "
[Show abstract][Hide abstract] ABSTRACT: Glucocorticoids (GC) are the most commonly prescribed medications for patients with inflammatory diseases, despite their well-known adverse metabolic effects. Previously, it was understood that the anti-inflammatory effects of the GC/GC receptor (GR) complex were mediated via transrepression, whilst the adverse metabolic effects were mediated via transactivation. It has recently become clear that this "divergent actions" paradigm of GC actions is likely insufficient. It has been reported that the GC/GR-mediated transactivation also contributes to the anti-inflammatory actions of GC, via up-regulation of key anti-inflammatory proteins. One of these is glucocorticoid-induced leucine zipper (GILZ), which inhibits inflammatory responses in a number of important immune cell lineages in vitro, as well as in animal models of inflammatory diseases in vivo. This review aims to compare the GILZ and GC effects on specific cell lineages and animal models of inflammatory diseases. The fact that the actions of GILZ permit a GILZ-based gene therapy to lack GC-like adverse effects presents the potential for development of new strategies to treat patients with inflammatory diseases.
Frontiers in Pharmacology 07/2014; 5:169. DOI:10.3389/fphar.2014.00169 · 3.80 Impact Factor
"Interestingly, nearly all of these genes were downregulated, suggesting that transcription is decreased early in the primary infestation. Of the few upregulated transcriptional regulators, Nfkbia and Tsc22d3 were of particular interest because they have been shown to inhibit NFkB and AP-1 pro-inflammatory pathways (Beaulieu and Morand, 2011). DNA repair molecules were also downregulated . "
[Show abstract][Hide abstract] ABSTRACT: Tick salivary glands produce complex cocktails of bioactive molecules that facilitate blood feeding and pathogen transmission by modulating host hemostasis, pain/itch responses, wound healing, and both innate and adaptive immunity. In this study, cutaneous responses at Dermacentor andersoni bite-sites were analyzed using Affymetrix mouse genome arrays and histopathology at 12, 48, 96 and 120 hours post- infestation (hpi) during primary infestations and 120hpi during secondary infestations. The microarray data suggests: (1) chemotaxis of neutrophils, monocytes, and other cell types; (2) production and scavenging of reactive oxygen species; and, (3) keratin- based wound healing responses. Histological analysis supported the microarray findings. At 12hpi, a mild inflammatory infiltrate was present in the dermis, especially concentrated at the junction between dermal connective tissue and underlying adipose tissue. A small lesion was located immediately under the hypostome and likely represents the feeding “pool.” Surprisingly, at 48hpi, the number of inflammatory cells had not increased from 12hpi, perhaps mirroring the reduction in gene expression seen at this time point. The feeding lesion is very well defined, and extravasated erythrocytes are readily evident around the hypostome. By 96hpi, the inflammatory infiltrate has increased dramatically and the feeding lesion appears to have moved deeper into the dermis. At 120hpi, most of the changes at 96hpi are intensified. The infiltrate is very dense, the epidermis is markedly thickened, the feeding lesion is poorly defined and the dermal tissue near the hypostome appears to be loosing its normal architecture. In conclusion, during D. andersoni feeding infiltration of inflammatory cells increases across time concurrent with significant changes in the epidermal and dermal compartments near the feeding tick. The importance of changes in the epidermal layer in the host response to ticks is not known, however, it is possib
Frontiers in Microbiology 05/2014; 5:198. DOI:10.3389/fmicb.2014.00198 · 3.99 Impact Factor
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