Glucocorticoid-induced Leucine Zipper Research Articles

Glucocorticoid receptor response and glucocorticoid-induced leucine zipper expression in neutrophils of critically ill patients with traumatic and non-traumatic brain injury

ObjectiveCritically ill patients, including those with brain injuries (BI), are frequently hospitalized in an intensive care unit (ICU). As with other critical states, an adequate stress response is essential for survival. Research on the hypothalamic-pituitary-adrenal gland (HPA) axis function in BI has primarily focused on assessing ACTH and cortisol levels. However, the immunological, metabolic, and hemodynamic effects of glucocorticoids (GCs) are mediated through the glucocorticoid receptor (GCR), a ubiquitously distributed intracellular receptor protein. Data on GCR-α expression and its signaling in acute BI injury are lacking.MethodsWe designed a prospective observational study, carried out in one academic multi-disciplinary ICU. Forty-two critically ill patients with acute (BI)were included. These patients suffered from traumatic BI (N= 20), subarachnoid hemorrhage (N= 12), intracranial hemorrhage (N= 7), or ischemic stroke (N= 3). All patients were steroid-free. Twenty-four age and sex-matched healthy controls were used for comparison.ResultsExpression of GCR-α and the glucocorticoid-inducible leucine zipper (GILZ), serum cortisol, interleukins (IL) 6, 8, 10 and TNF- α, and the BI biomarkers glial fibrillary acidic protein (GFAP) and total Tau were measured on ICU admission (within 48 hours) and 5-7 days from admission. Compared to healthy controls, in the critically ill patients with BI, GCR-α mRNA expression was significantly downregulated on admission, and after 5-7 days in the ICU (2.3-fold, p<0.05 and 2.6-fold, p<0.01, respectively). Even though GCR-α was downregulated, its downstream gene, GILZ, was expressed at the same levels as in normal controls on admission and was significantly upregulated 5-7 days following admission (2-fold, p<0.001). TNF-α levels were undetectable at both time-points. GCR-α expression levels inversely correlated with IL-6. The levels of cortisol and the BI biomarkers did not differ between the 2 time-points.ConclusionsWe provide novel evidence on the downregulated expression and upregulated signaling of the ligand-binding and functionally active GCR-α isoform in the polymorphonuclear neutrophils (PMNs) of critically ill patients with BI. The increased GILZ expression indicates an increased GC sensitivity in the PMNs of BI critically ill patients.

High expression of L-GILZ transcript variant 1 (GILZ TV 1) is associated with increased 30-day sepsis mortality, and a high expression ratio possibly contraindicates hydrocortisone administration

BackgroundSepsis presents a challenge due to its complex immune responses, where balance between inflammation and anti-inflammation is critical for survival. Glucocorticoid-induced leucine zipper (GILZ) is key protein in achieving this balance, suppressing inflammation and mediating glucocorticoid response. This study aims to investigate GILZ transcript variants in sepsis patients and explore their potential for patient stratification and optimizing glucocorticoid therapy.MethodsSepsis patients meeting the criteria outlined in Sepsis-3 were enrolled, and RNA was isolated from whole blood samples. Quantitative mRNA expression of GILZ transcript variants in both sepsis patient samples (n = 121) and the monocytic U937 cell line (n = 3), treated with hydrocortisone and lipopolysaccharides, was assessed using quantitative PCR (qPCR).ResultsElevated expression of GILZ transcript variant 1 (GILZ TV 1) serves as a marker for heightened 30-day mortality in septic patients. Increased levels of GILZ TV 1 within the initial day of sepsis onset are associated with a 2.2-[95% CI 1.2–4.3] fold rise in mortality, escalating to an 8.5-[95% CI 2.0–36.4] fold increase by day eight. GILZ TV1 expression is enhanced by glucocorticoids in cell culture but remains unaffected by inflammatory stimuli such as LPS. In septic patients, GILZ TV 1 expression increases over the course of sepsis and in response to hydrocortisone treatment. Furthermore, a high expression ratio of transcript variant 1 relative to all GILZ mRNA TVs correlates with a 2.3-fold higher mortality rate in patients receiving hydrocortisone treatment.ConclusionHigh expression of GILZ TV 1 is associated with a higher 30-day sepsis mortality rate. Moreover, a high expression ratio of GILZ TV 1 relative to all GILZ transcript variants is a parameter for identifying patient subgroups in which hydrocortisone may be contraindicated.

Intermittent pulses of methylprednisolone with low-dose prednisone attenuate lupus symptoms in B6.MRL-Faslpr/J mice with fewer glucocorticoid side effects

Glucocorticoids (GCs) are potent anti-inflammatory and immunosuppressant medications and remain the cornerstone of systemic lupus erythematosus (SLE) therapy. However, ongoing exposure to GCs has the potential to elicit multiple adverse effects. Considering the irreplaceability of GCs in SLE therapy, it is important to explore the optimal regimen of GCs. Here, we compared the long-term efficacy and safety of pulsed and oral GC therapy in a lupus-prone mouse model. Mice were grouped using a randomized block design. We monitored survival rates, proteinuria, serum autoantibodies, and complement 3 (C3) levels up to 28 weeks of age, and assessed renal damage, bone quality, lipid deposition in the liver and marrow, glucose metabolic parameters, and levels of hormones of the hypothalamic-pituitary-adrenal (HPA) axis. Finally, we explored the mechanisms underlying the superior efficacy of the pulse regimen over oral prednisone regimen. We found that both GC regimens alleviated the poor survival rate, proteinuria, and glomerulonephritis, while also reducing serum autoantibodies and increasing the level of C3. The pulsed GC regimen showed less resistance to insulin, less suppression of the HPA axis, less bone loss, and less bone marrow fat deposition than the oral GC regimen. Additionally, GC-induced leucine zipper (GILZ) was significantly overexpressed in the GC pulse group. These results suggest that the GC pulse regimen ameliorated symptoms in lupus-prone mice, with fewer side effects, which may be related to GILZ overexpression. Our findings offer a potentially promising GC treatment option for SLE.

Immunomodulation by glucocorticoid-induced leucine zipper in macrophages: enhanced phagocytosis, protection from pyroptosis, and altered mitochondrial function.

Glucocorticoids, which have long served as fundamental therapeutics for diverse inflammatory conditions, are still widely used, despite associated side effects limiting their long-term use. Among their key mediators is glucocorticoid-induced leucine zipper (GILZ), recognized for its anti-inflammatory and immunosuppressive properties. Here, we explore the immunomodulatory effects of GILZ in macrophages through transcriptomic analysis and functional assays. Bulk RNA sequencing of GILZ knockout and GILZ-overexpressing macrophages revealed significant alterations in gene expression profiles, particularly impacting pathways associated with the inflammatory response, phagocytosis, cell death, mitochondrial function, and extracellular structure organization activity. GILZ-overexpression enhances phagocytic and antibacterial activity against Salmonella typhimurium and Escherichia coli, potentially mediated by increased nitric oxide production. In addition, GILZ protects macrophages from pyroptotic cell death, as indicated by a reduced production of reactive oxygen species (ROS) in GILZ transgenic macrophages. In contrast, GILZ KO macrophages produced more ROS, suggesting a regulatory role of GILZ in ROS-dependent pathways. Additionally, GILZ overexpression leads to decreased mitochondrial respiration and heightened matrix metalloproteinase activity, suggesting its involvement in tissue remodeling processes. These findings underscore the multifaceted role of GILZ in modulating macrophage functions and its potential as a therapeutic target for inflammatory disorders, offering insights into the development of novel therapeutic strategies aimed at optimizing the benefits of glucocorticoid therapy while minimizing adverse effects.

Reprofiling synthetic glucocorticoid-induced leucine zipper fusion peptide as a novel and effective hair growth promoter.

Hair is a biofilament with unique multi-dimensional values. In human, in addition to physiologic impacts, hair loss and hair related disorders can affect characteristic features, emotions, and social behaviors. Despite significant advancement, there is a dire need to explore alternative novel therapies with higher efficacy, less side effects and lower cost to promote hair growth to treat hair deficiency. Glucocorticoid-induced leucine zipper (GILZ) is a protein rapidly induced by glucocorticoids. Studies from our group and many others have suggested that a synthetic form of GILZ, TAT-GILZ, a fusion peptide of trans-activator of transcription and GILZ, can function as a potent regulator of inflammatory responses, re-establishing and maintaining the homeostasis. In this study, we investigate whether TAT-GILZ could promote and contribute to hair growth. For our pre-clinical model, we used 9-12 week-old male BALB/c and nude (athymic, nu/J) mice. We applied TAT-GILZ and/or TAT (vehicle) intradermally to depilated/hairless mice. Direct observation, histological examination, and Immunofluorescence imaging were used to assess the effects and compare different treatments. In addition, we tested two current treatment for hair loss/growth, finasteride and minoxidil, for optimal evaluation of TAT-GILZ in a comparative fashion. Our results showed, for the first time, that synthetic TAT-GILZ peptide accelerated hair growth on depilated dorsal skin of BALB/c and induced hair on the skin of athymic mice where hair growth was not expected. In addition, TAT-GILZ was able to enhance hair follicle stem cells and re-established the homeostasis by increasing counter inflammatory signals including higher regulatory T cells and glucocorticoid receptors. In conclusion, our novel findings suggest that reprofiling synthetic TAT-GILZ peptide could promote hair growth by increasing hair follicle stem cells and re-establishing homeostasis.

The Association between the rs3747406 Polymorphism in the Glucocorticoid-Induced Leucine Zipper Gene and Sepsis Survivals Depends on the SOFA Score.

The variability in mortality in sepsis could be a consequence of genetic variability. The glucocorticoid system and the intermediate TSC22D3 gene product-glucocorticoid-induced leucine zipper-are clinically relevant in sepsis, which is why this study aimed to clarify whether TSC22D3 gene polymorphisms contribute to the variance in sepsis mortality. Blood samples for DNA extraction were obtained from 455 patients with a sepsis diagnosis according to the Sepsis-III criteria and from 73 control subjects. A SNP TaqMan assay was used to detect single-nucleotide polymorphisms (SNPs) in the TSC22D3 gene. Statistical and graphical analyses were performed using the SPSS Statistics and GraphPad Prism software. C-allele carriers of rs3747406 have a 2.07-fold higher mortality rate when the sequential organ failure assessment (SOFA) score is higher than eight. In a multivariate COX regression model, the SNP rs3747406 with a SOFA score ≥ 8 was found to be an independent risk factor for 30-day survival in sepsis. The HR was calculated to be 2.12, with a p-value of 0.011. The wild-type allele was present in four out of six SNPs in our cohort. The promoter of TSC22D3 was found to be highly conserved. However, we discovered that the C-allele of rs3747406 poses a risk for sepsis mortality for SOFA Scores higher than 6.

Expression profiles of glucocorticoid-inducible proteins in human papilloma virus-related oropharyngeal squamous cell carcinoma.

Human papillomavirus virus-related oropharyngeal squamous cell carcinoma (HPV-OPSCC) comprises a significant portion of head and neck cancers. Several glucocorticoid-inducible proteins play important roles in pathogenesis of some cancers but their status and roles in HPV-OPSCC remain elusive; these include the glucocorticoid-induced leucine zipper (GILZ), Annexin-A1 and serum glucocorticoid-regulated kinase-1 (SGK-1). We determined expression profiles of these proteins, using immunohistochemistry, in archived biopsy samples of patients diagnosed with HPV-OPSCC; samples of non-cancer oral lesions (e.g., hyperkeratosis) were used as controls. GILZ staining was primarily confined to nuclei of all tissues but, in HPV-OPSCC specimens, neoplastic cells exhibiting mitosis displayed prominent cytoplasmic GILZ expression. On the other hand, nuclear, cytoplasmic and membranous Annexin-A1 staining was observed in suprabasal cell layers of control specimens. A noted feature of the HPV-OPSCC specimens was few clusters of matured and differentiated nonbasaloid cells that showed prominent nuclear and cytoplasmic Annexin-A1 staining while the remainder of the tumor mass was devoid of staining. Cytoplasmic and nuclear staining for SGK-1 was prominent for control than PV-OPSCC specimens while staining for phosphorylated SGK-1 (pSGK-1; active) was prominent for cell membrane and cytoplasm of control specimens but HPV-OPSCC specimens showed mild and patchy nuclear and cytoplasmic staining. Semi-quantitative analysis of GILZ immunostaining indicated increased staining area but similar normalized staining for HPV-OPSCC compared to control specimens. By contrast, staining area and normalized staining were reduced for other proteins in HPV-OPSCC than control specimens. Our collective observations suggest differential cellular localization and expression of glucocorticoid-inducible proteins in HPV-OPSCC suggestive of different functional roles in pathogenesis of this condition.

Effects of acute exercise and training status on glucocorticoid-induced leucine zipper (GILZ) expression in human skeletal muscle

Interactions between statin therapy and physical exercise complicate effective cardiovascular prevention. Emerging evidence suggests that muscle strain related changes in the expression of the glucocorticoid-induced leucine zipper (GILZ) may be involved. Therefore, we measured GILZ mRNA expression levels in M. vastus lateralis samples of 32 healthy individuals before and after a standardized bout of strength or endurance exercise. Overall, we found a highly significant downregulation of GILZ after exercise training (p < 0.001). Within-subgroup changes were statistically significant only after strength training, supporting the role of muscle (as opposed to cardiocirculatory) strain. If confirmed, this may help fitting training recommendations and medication.

Anti-Inflammatory Effects of Synthetic Peptides Based on Glucocorticoid-Induced Leucine Zipper (GILZ) Protein for the Treatment of Inflammatory Bowel Diseases (IBDs).

Glucocorticoids (GCs) are commonly used to treat autoimmune and inflammatory diseases, but their clinical effects and long-term use can lead to serious side effects. New drugs that can replace GCs are needed. Glucocorticoid-induced leucine zipper (GILZ) is induced by GCs and mediates many of their anti-inflammatory effects, such as inhibiting the pro-inflammatory molecule NF-κB. The GILZ C-terminal domain (PER region) is responsible for GILZ/p65NF-κB interaction and consequent inhibition of its transcriptional activity. A set of five short peptides spanning different parts of the PER region of GILZ protein was designed, and their anti-inflammatory activity was tested, both in vitro and in vivo. We tested the biological activity of GILZ peptides in human lymphocytic and monocytic cell lines to evaluate their inhibitory effect on the NF-κB-dependent expression of pro-inflammatory cytokines. Among the tested peptides, the peptide named PEP-1 demonstrated the highest efficacy in inhibiting cell activation in vitro. Subsequently, PEP-1 was further evaluated in two in vivo experimental colitis models (chemically induced by DNBS administration and spontaneous colitis induced in IL-10 knock-out (KO) mice (to assess its effectiveness in counteracting inflammation. Results show that PEP-1 reduced disease severity in both colitis models associated with reduced NF-κB pro-inflammatory activity in colon lamina propria lymphocytes. This study explored GILZ-based 'small peptides' potential efficacy in decreasing lymphocyte activation and inflammation associated with experimental inflammatory bowel diseases (IBDs). Small peptides have several advantages over the entire protein, including higher selectivity, better stability, and bioavailability profile, and are easy to synthesize and cost-effective. Thus, identifying active GILZ peptides could represent a new class of drugs for treating IBD patients.

Glucocorticoid dysfunction in children with severe malaria.

Malaria remains a widespread health problem with a huge burden. Severe or complicated malaria is highly lethal and encompasses a variety of pathological processes, including immune activation, inflammation, and dysmetabolism. Previously, we showed that adrenal hormones, in particular glucocorticoids (GCs), play critical roles to maintain disease tolerance during Plasmodium infection in mice. Here, GC responses were studied in Cameroon in children with uncomplicated malaria (UM), severe malaria (SM) and asymptomatic controls (AC). To determine the sensitivity of leukocytes to GC signaling on a transcriptional level, we measured the ex vivo induction of glucocorticoid induced leucine zipper (GILZ) and FK506-binding protein 5 (FKBP5) by GCs in human and murine leukocytes. Targeted tracer metabolomics on peripheral blood mononuclear cells (PBMCs) was performed to detect metabolic changes induced by GCs. Total cortisol levels increased in patients with clinical malaria compared to AC and were higher in the SM versus UM group, while cortisol binding globulin levels were unchanged and adrenocorticotropic hormone (ACTH) levels were heterogeneous. Induction of both GILZ and FKBP5 by GCs was significantly reduced in patients with clinical malaria compared to AC and in malaria-infected mice compared to uninfected controls. Increased activity in the pentose phosphate pathway was found in the patients, but this was not affected by ex vivo stimulation with physiological levels of hydrocortisone. Interestingly, hydrocortisone induced increased levels of cAMP in AC, but not in clinical malaria patients. Altogether, this study shows that patients with SM have increased cortisol levels, but also a decreased sensitivity to GCs, which may clearly contribute to the severity of disease.

Analysis of glucocorticoid responsive and circadian clock molecules in Alzheimer’s disease brain tissues.

AbstractBackgroundUnder basal non‐stressed brain conditions, a control system that includes an inherent molecular clock activation, immunomodulatory role of glucocorticoids and nuclear factor‐kappa B (NF‐κB) signaling is essential to prevent excessive inflammation and to effectively return to homeostasis. This results in a continuous competition between feedback and feedforward control. Chronic stress and dysregulated molecular clock are implicated as significant risk factors for neurodegeneration. In unstimulated mice, the core clock gene BMAL1 and the glucocorticoid induced leucine zipper (GILZ, a glucocorticoid responsive gene) are highly expressed in hippocampal microglia. The expressions of these two genes are positively correlated with circulating corticosterone. Mechanistically, GILZ inhibits nuclear translocation of NF‐κB p65 and functions as an anti‐inflammatory molecule. BMAL1 on the other hand, independent of its circadian partner CLOCK, inhibits the glucocorticoid receptor mediated transactivation of GILZ. Elevated plasma corticosterone and age‐related decrease in BMAL1 are associated with increased activation of NF‐κB p65 and susceptibility to neuropathology. We have observed that the GILZ expression in the hippocampus is inversely related to that of NF‐κB p65 and IBA1 in mouse models of Alzheimer’s disease (AD). Taken together, we hypothesize that the GILZ expression will correlate positively with core clock genes and negatively with markers of gliosis and inflammation in neurodegenerative diseases.MethodWe evaluated the expressions of circadian markers BMAL1 and Period genes (Per1, Per2 and Per3); that of glial cell surface markers Iba1 and GFAP and that of GILZ and NF‐kB as markers of inflammatory system in AD brain tissues by immunohistochemistry and real‐time polymerase chain reaction (RT‐PCR).ResultGILZ expression was reduced in the hippocampus and pre‐frontal cortex of AD tissues, was inversely related to p65, Iba1 and GFAP expressions and directly related to BMAL1 and Per2.ConclusionGILZ could potentially function as a molecular modulator at the intersection of the three systems.

GILZ Modulates the Recruitment of Monocytes/Macrophages Endowed with a Resolving Phenotype and Favors Resolution of Escherichia coli Infection.

Macrophages are important effectors of inflammation resolution that contribute to the elimination of pathogens and apoptotic cells and restoration of homeostasis. Pre-clinical studies have evidenced the anti-inflammatory and pro-resolving actions of GILZ (glucocorticoid-induced leucine zipper). Here, we evaluated the role of GILZ on the migration of mononuclear cells under nonphlogistic conditions and Escherichia coli-evoked peritonitis. TAT-GILZ (a cell-permeable GILZ-fusion protein) injection into the pleural cavity of mice induced monocyte/macrophage influx alongside increased CCL2, IL-10 and TGF-β levels. TAT-GILZ-recruited macrophages showed a regulatory phenotype, exhibiting increased expression of CD206 and YM1. During the resolving phase of E. coli-induced peritonitis, marked by an increased recruitment of mononuclear cells, lower numbers of these cells and CCL2 levels were found in the peritoneal cavity of GILZ-deficient mice (GILZ-/-) when compared to WT. In addition, GILZ-/- showed higher bacterial loads, lower apoptosis/efferocytosis counts and a lower number of macrophages with pro-resolving phenotypes. TAT-GILZ accelerated resolution of E. coli-evoked neutrophilic inflammation, which was associated with increased peritoneal numbers of monocytes/macrophages, enhanced apoptosis/efferocytosis counts and bacterial clearance through phagocytosis. Taken together, we provided evidence that GILZ modulates macrophage migration with a regulatory phenotype, inducing bacterial clearance and accelerating the resolution of peritonitis induced by E. coli.

The role of the glucocorticoid receptor and its impact on steroid response in moderate-severe COVID-19 patients

The effect of corticosteroid therapy in COVID-19 patients is mediated by its suppressive effect on the regulations of inflammatory response. However, its clinical outcome is often unpredictable. This study aimed to explore the role of glucocorticoid receptors in corticosteroid response in Moderate-Severe COVID-19 patients. In this cross-sectional study, we attempted to find the relationship between the expression of the glucocorticoid receptor (encoded by NR3C1), the variation of glucocorticoid receptors isoform, and the mutations of glucocorticoid receptors exon with clinical response to corticosteroids. In addition, the relationship between glucocorticoid receptors expression and the expression of IκBα (encoded by NFKBIA) and glucocorticoid-induced leucine zipper protein (GILZ; encoded by TSC22D3) as steroid pathways was also evaluated. Thirty-four COVID-19 patients were studied. Blood was drawn before and on day 5 of corticosteroid treatment. Glucocorticoid receptors expression, isoform, and mutation were determined by RNA sequencing from white blood cells. Based on the improvement of clinical and oxygen status, patients were classified into responder and non-responder groups. Of thirty-four patients, 23 (67.6%) showed excellent responses to corticosteroids, and 11 (32.4%) were non-responders. The NR3C1 gene expression was significantly higher in the responsive group at baseline and after five days of glucocorticoid treatment. Isoform variant and mutation of glucocorticoid receptors did not correlate with clinical response. The expression of IκBα and GILZ correlated positively with glucocorticoid receptors expression. This study elucidates the relationship between glucocorticoid receptor expression with therapeutic responses to corticosteroids in moderate-severe COVID-19.

Association of GILZ with MUC2, TLR2, and TLR4 in Inflammatory Bowel Disease.

Ulcerative colitis (UC) and Crohn's Disease (CD) are chronic relapsing inflammatory diseases that are caused by genetic, environmental, and immune factors. Treatment strategies are currently based on symptomatic control by immunosuppression. The glucocorticoid-induced leucine zipper (GILZ), a mediator of several effects of glucocorticoids, was recently found to be secreted by goblet cells and play a role in inflammatory bowel disease (IBD). This study investigates which genes GILZ is associated with in its role in intestinal barrier functions. We examined datasets from the Gene Expression Omnibus (GEO) and ArrayExpress profiles of the gut of healthy subjects (HSs), as well as UC and CD patients. The human colonic epithelial HT29 cell line was used for in vitro validation experiments. GILZ was significantly correlated with MUC2, TLR2, and TLR4. In particular, an inverse correlation was found between the GILZ and MUC2 in HS and patients with IBD, mostly in those with an active disease. Further, direct pairwise correlations for GILZ/TLR2 and GILZ/TLR4 were found in HSs and UC patients, but not in CD patients. Overall, our results reveal the crosstalk at the transcription level between the GILZ, MUC2, and TLRs in the mucosal barrier through common pathways, and they open up new perspectives in terms of mucosal healing in IBD patients.

Do Corticosteroid Receptor mRNA Levels Predict the Expression of Their Target Genes?

The glucocorticoid stress hormones affect brain function via high-affinity mineralocorticoid receptors (MRs) and lower-affinity glucocorticoid receptors (GRs). MR and GR not only differ in affinity for ligands, but also have distinct, sometimes opposite, actions on neuronal excitability and other cellular and higher-order parameters related to cerebral function. GR and MR messenger RNA (mRNA) levels are often used as a proxy for the responsiveness to glucocorticoids, assuming proportionality between mRNA and protein levels. This may be especially relevant for the MR, which because of its high affinity is already largely occupied at low basal (trough) hormone levels. Here we explore how GR and MR mRNA levels are associated with the expression of a shared target gene, glucocorticoid-induced leucine zipper (GILZ, coded by Tsc22d3) with basal and elevated levels of corticosterone in male mice, using in situ hybridization. Depending on the hippocampal subfield and the corticosterone levels, mRNA levels of MR rather than GR mostly correlated with GILZ mRNA in the hippocampus and hypothalamus at the bulk tissue level. At the individual cell level, these correlations were much weaker. Using publicly available single-cell RNA sequencing data, we again observed that MR and GR mRNA levels were only weakly correlated with target gene expression in glutamatergic and GABAergic neurons. We conclude that MR mRNA levels can be limiting for receptor action, but many other cell-specific and region-specific factors ultimately determine corticosteroid receptor action. Altogether, our results argue for caution while interpreting the consequences of changed receptor expression for the response to glucocorticoids.

Type 1 interferon suppresses expression and glucocorticoid induction of glucocorticoid-induced leucine zipper (GILZ).

SLE is a systemic multi-organ autoimmune condition associated with reduced life expectancy and quality of life. Glucocorticoids (GC) are heavily relied on for SLE treatment but are associated with detrimental metabolic effects. Type 1 interferons (IFN) are central to SLE pathogenesis and may confer GC insensitivity. Glucocorticoid-induced leucine zipper (GILZ) mediates many effects of GC relevant to SLE pathogenesis, but the effect of IFN on GC regulation of GILZ is unknown. We performed in vitro experiments using human PBMC to examine the effect of IFN on GILZ expression. JAK inhibitors tofacitinib and tosylate salt were used in vivo and in vitro respectively to investigate JAK-STAT pathway dependence of our observations. ChiP was performed to examine glucocorticoid receptor (GR) binding at the GILZ locus. Several public data sets were mined for correlating clinical data. High IFN was associated with suppressed GILZ and reduced GILZ relevant to GC exposure in a large SLE population. IFN directly reduced GILZ expression and suppressed the induction of GILZ by GC in vitro in human leukocytes. IFN actions on GILZ expression were dependent on the JAK1/Tyk2 pathway, as evidenced by loss of the inhibitory effect of IFN on GILZ in the presence of JAK inhibitors. Activation of this pathway led to reduced GR binding in key regulatory regions of the GILZ locus. IFN directly suppresses GILZ expression and GILZ upregulation by GC, indicating a potential mechanism for IFN-induced GC resistance. This work has important implications for the ongoing development of targeted GC-sparing therapeutics in SLE.

Expression of concern on 'glucocorticoid-induced leucine zipper (GILZ)/NF-κB interaction: role of GILZ homo-dimerization and C-terminal domain'.

Expression of concern on 'glucocorticoid-induced leucine zipper (GILZ)/NF-κB interaction: role of GILZ homo-dimerization and C-terminal domain'.

The novel role of glucocorticoid-induced leucine zipper as a marker of mucosal healing in inflammatory bowel diseases

Glucocorticoid-induced leucin zipper (GILZ) mediates the effects of glucocorticoids in immune cells, but little is known about its role in both the gastro-intestinal (GI) mucosa and inflammatory bowel diseases (IBD) in humans. To investigate the GILZ protein expression profile in the GI tract, mucosal biopsies from 80 patients were retrospectively enrolled in this study and subdivided into three groups: 1) patients without clinical-endoscopic and histological evidence of IBD; 2) IBD patients; 3) patients with chronic atrophic gastritis (CAG) and Barrett esophagus (BE), both characterized by intestinal metaplasia (IM). GILZ expression was assessed by immunohistochemical and immunofluorescence methods. Our results showed that GILZ protein was strongly expressed in the secretory cells in healthy mucosa. GILZ expression was reduced in goblet cells in active disease, whereas it was restored in quiescent diseases. Conversely, entero-endocrine cells were not involved in such inflammation-driven dynamics, as GILZ expression remained detectable in active disease. Moreover, GILZ was expressed in IM, but was limited to CAG, and was not detected in BE. In summary, GILZ acts as a secretory protein in the GI mucosa in healthy, hyperplastic and metaplastic conditions. Its secretion by goblet cells is mostly affected by neutrophils mucosal infiltration and seems to be directly related to active mucosal inflammation in IBD. Overall, our findings suggest that GILZ is a suitable molecule to be considered as a histological marker of mucosal healing.

GILZ regulates type I interferon release and sequesters STAT1

Glucocorticoids remain a mainstay of modern medicine due to their ability to broadly suppress immune activation. However, they cause severe adverse effects that warrant urgent development of a safer alternative. The glucocorticoid-induced leucine zipper (GILZ) gene, TSC22D3, is one of the most highly upregulated genes in response to glucocorticoid treatment, and reduced GILZ mRNA and protein levels are associated with increased severity of inflammation in systemic lupus erythematosus (SLE), Ulcerative Colitis, Psoriasis, and other autoimmune/autoinflammatory diseases. Here, we demonstrate that low GILZ permits expression of a type I interferon (IFN) signature, which is exacerbated in response to TLR7 and TLR9 stimulation. Conversely, overexpression of GILZ prevents IFN-stimulated gene (ISG) up-regulation in response to IFNα. Moreover, GILZ directly binds STAT1 and prevents its nuclear translocation, thereby negatively regulating IFN-induced gene expression and the auto-amplification loop of the IFN response. Thus, GILZ powerfully regulates both the expression and action of type I IFN, suggesting restoration of GILZ as an attractive therapeutic strategy for reducing reliance on glucocorticoids.

Network Pharmacology and ­Experimental Analyses of the Mechanism of Analgesic and Glucose Intolerance Through Glucocorticoid Signaling in C57 Mice Treated with Water Extract of Prunella vulgaris L. Spica

The aim of this study was to confirm the anti-inflammatory effect and explore the adverse effects and underlying mechanisms of Prunella vulgaris L., which has been extensively used for hundreds of years in East Asia. Network pharmacology studies predicted that glucocorticoids (GCs), GC-targeting molecules, and brain-derived neurotrophic factor (BDNF) were intensively involved in the anti-inflammation and glucose intolerance. To attest the effects and underlying mechanisms, C57 male mice were randomly divided into 5 groups, control (C), dexamethasone (Dex), water extract of P. vulgaris (PE 35 or 70 mg), and PE (70 mg) + mifepristone (PEM). After a 3-week treatment, acetic acid-induced writhing and hot plate tests confirmed the peripheral and central analgesic effects, respectively. Plasma GCs and BDNF were significantly increased. Coincidently, plasma pro-inflammatory cytokines, including IL1β, IL6, and IL10, were decreased by PE treatment, which were blocked by the application of mifepristone ( P &lt; 0.5). Western blots confirmed GC receptor (GR) translocation, and decreased cyclooxygenase 2 in the lumber spine by PE treatment. Food intake was impeded after a 4-week PE treatment, but the ratio of bodyweight gain to food intake was increased in a time-dependent manner. An intraperitoneal glucose tolerance test disclosed that PE treatment impaired glucose disposal in mice. Quantitative polymerase chain reaction (PCR) showed that hepatic GC-responsive genes such as GC-induced leucine zipper protein and glucose-6-phosphatase catalytic subunit 1 were up-regulated, and hypothalamic neuropeptide Y and agouti-related protein expressions were decreased by PE treatment. Hypothalamic BDNF was up-regulated, whereas hepatic BDNF was down-regulated. The regulation of these genes by PE was reversed by mifepristone administration. In conclusion, PE treatment plays analgesic and glucose regulation roles simultaneously through GC-induced signaling pathways, and P. vulgaris may provide a natural ligand of GR for the treatment of inflammation with glucose dysregulation.