Glucocorticoid-Induced Leucine Zipper Is Expressed in Human Neutrophils and Promotes Apoptosis through Mcl-1 Down-Regulation

Tsc22d3 promotes morphine tolerance in mice through the GPX4 ferroptosis pathway

BACKGROUND

Morphine tolerance refers to gradual reduction in response to drug with continuous or repeated use of morphine, requiring higher doses to achieve same effect.

METHODS

The morphine tolerance dataset GSE7762 profiles, obtained from gene expression omnibus (GEO) database, were used to identify differentially expressed genes (DEGs). Weighted Gene Co-expression Network Analysis (WGCNA) was applied to explore core modules of DEGs related to morphine tolerance. Core genes were input into Comparative Toxicogenomics Database (CTD). Animal experiments were performed to validate role of Tsc22d3 in morphine tolerance and its relationship with ferroptosis-related pathway.

RESULTS

500 DEGs were identified. DEGs were primarily enriched in negative regulation of brain development, neuronal apoptosis processes, and neurosystem development. Core gene was identified as Tsc22d3. Tsc22d3 gene-associated miRNAs were mmu-miR-196b-5p and mmu-miR-196a-5p. Compared to Non-morphine tolerant group, Tsc22d3 expression was significantly upregulated in Morphine tolerant group. Tsc22d3 expression was upregulated in Morphine tolerant+Tsc22d3_OE, expression of HIF-1alpha, GSH, GPX4 in GPX4 ferroptosis-related pathway showed a more pronounced decrease. As Tsc22d3 expression was downregulated in Morphine tolerant+Tsc22d3_KO, expression of HIF-1alpha, GSH, GPX4 in GPX4 ferroptosis-related pathway exhibited a more pronounced increase. Upregulation of Tsc22d3 in Morphine tolerant+Tsc22d3_OE led to a more pronounced increase in expression of apoptosis proteins (P53, Caspase-3, Bax, SMAC, FAS). The expression of inflammatory factors (IL6, TNF-alpha, CXCL1, CXCL2) showed a more pronounced increase with upregulated Tsc22d3 expression in Morphine tolerant+Tsc22d3_OE.

CONCLUSIONS

Tsc22d3 is highly expressed in brain tissue of morphine-tolerant mice, activating ferroptosis pathway, enhancing apoptosis, promoting inflammatory responses in brain cells.

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.

Synergistic combination of isogarcinol isolated from edible fruits of Garcinia multiflora and dexamethasone to overcome leukemia glucocorticoid resistance

Isogarcinol (ISO), a cytotoxic polycyclic polyprenylated acylphloroglucinol isolated from the edible fruits of Garcinia multiflora. However, synergistic combination of ISO and dexamethasone (DEX) to overcome leukemia glucocorticoid resistance has never been investigated. Therefore, in this study, the effects of ISO in combination with DEX was conducted on leukemia in vivo and glucocorticoid resistance in vitro. As a result, the combination of the two compounds could efficiently inhibit leukemia progression in mice and reverse DEX resistance in acute lymphoblastic leukemia (ALL) Jurkat cells. Significantly, our findings indicated that c-Myc may be a potential target of ISO, as it is involved in cell cycle arrest and apoptosis by the combination of ISO and DEX in Jurkat cells. Furthermore, western blot analysis revealed that ISO and DEX inhibits the PI3K/Akt/mTOR signaling pathway and promotes the nuclear translocation of glucocorticoid receptor (GR), which activates target genes NR3C1 and TSC22D3, leading to apoptosis in Jurkat cells. Hence, our results suggest that ISO, as a safe and effective food-derived agent, can enhance the anti-leukemia effects of DEX.

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.

Glucocorticoid-Induced Leucine Zipper Alleviates Lung Inflammation and Enhances Bacterial Clearance During Pneumococcal Pneumonia

Pneumonia is a leading cause of morbidity and mortality. While inflammation is a host protective response that ensures bacterial clearance, a finely regulated response is necessary to prevent bystander tissue damage. Glucocorticoid (GC)-induced leucine zipper (GILZ) is a GC-induced protein with anti-inflammatory and proresolving bioactions, yet the therapeutical role of GILZ in infectious diseases remains unexplored. Herein, we investigate the role and effects of GILZ during acute lung injury (ALI) induced by LPS and Streptococcus pneumoniae infection. GILZ deficient mice (GILZ^−/−) presented more severe ALI, characterized by increased inflammation, decreased macrophage efferocytosis and pronounced lung damage. In contrast, pulmonary inflammation, and damage were attenuated in WT mice treated with TAT-GILZ fusion protein. During pneumococcal pneumonia, TAT-GILZ reduced neutrophilic inflammation and prevented the associated lung damage. There was also enhanced macrophage efferocytosis and bacterial clearance in TAT-GILZ-treated mice. Mechanistically, TAT-GILZ enhanced macrophage phagocytosis of pneumococcus, which was lower in GILZ^−/− macrophages. Noteworthy, early treatment with TAT-GILZ rescued 30% of S. pneumoniae-infected mice from lethal pneumonia. Altogether, we present evidence that TAT-GILZ enhances host resilience and resistance to pneumococcal pneumonia by controlling pulmonary inflammation and bacterial loads leading to decreased lethality. Exploiting GILZ pathways holds promise for the treatment of severe respiratory infections.

GILZ as a Regulator of Cell Fate and Inflammation

One of the human body’s initial responses to stress is the adrenal response, involving the release of mediators that include adrenaline and glucocorticoids (GC). GC are involved in controlling the inflammatory and immune response mechanisms. Of these, the molecular mechanisms that contribute to anti-inflammatory effects warrant more investigation. Previously, we found that GC induced GILZ (glucocorticoid-induced leucine zipper) quickly and widely in thymocytes, T lymphocytes, and other leukocytes. GILZ regulates the activation of cells and is an essential mediator of endogenous GC and the majority of GC anti-inflammatory effects. Further research in this regard could lead to the development of an anti-inflammatory treatment that yields the therapeutic outcomes of GC but without their characteristic adverse effects. Here, we examine the mechanisms of GILZ in the context of GC. Specifically, we review its role in the proliferation and differentiation of cells and in apoptosis. We also examine its involvement in immune cells (macrophages, neutrophils, dendritic cells, T and B lymphocytes), and in non-immune cells, including cancer cells. In conclusion, GILZ is an anti-inflammatory molecule that could mediate the immunomodulatory activities of GC, with less adverse effects, and could be a target molecule for designing new therapies to treat inflammatory diseases.

Multi-Tissue Characterization of GILZ Expression in Dendritic Cell Subsets at Steady State and in Inflammatory Contexts

Dendritic cells (DCs) are key players in the control of tolerance and immunity. Glucocorticoids (GCs) are known to regulate DC function by promoting their tolerogenic differentiation through the induction of inhibitory ligands, cytokines, and enzymes. The GC-induced effects in DCs were shown to critically depend on increased expression of the Glucocorticoid-Induced Leucine Zipper protein (GILZ). GILZ expression levels were further shown to control antigen-presenting cell function, as well as T-cell priming capacity of DCs. However, the pattern of GILZ expression in DC subsets across tissues remains poorly described, as well as the modulation of its expression levels in different pathological settings. To fill in this knowledge gap, we conducted an exhaustive analysis of GILZ relative expression levels in DC subsets from various tissues using multiparametric flow cytometry. This study was performed at steady state, in the context of acute as well as chronic skin inflammation, and in a model of cancer. Our results show the heterogeneity of GILZ expression among DC subsets as well as the complexity of its modulation, that varies in a cell subset- and context-specific manner. Considering the contribution of GILZ in the control of DC functions and its potential as an immune checkpoint in cancer settings, these results are of high relevance for optimal GILZ targeting in therapeutic strategies.

Glucocorticoid-Induced Leucine Zipper-Mediated TLR2 Downregulation Accounts for Reduced Neutrophil Activity Following Acute DEX Treatment

Glucocorticoids are the most powerful anti-inflammatory and immunosuppressive pharmacological drugs available, despite their adverse effects. Glucocorticoid-induced leucine zipper (GILZ) is a glucocorticoid-induced gene that shares several anti-inflammatory properties with glucocorticoids. Although immunosuppressive effects of glucocorticoids on neutrophils remain poorly understood, we previously demonstrated that GILZ suppresses neutrophil activation under glucocorticoid treatment. Here, we sought to explore the regulation of Toll-like receptor 2 (TLR2) by the synthetic glucocorticoid dexamethasone (DEX) on neutrophils and the associated GILZ involvement. Peripheral blood neutrophils were isolated from wild type and GILZ-knock-out (KO) mice. TLR2 was found to be downregulated by the in vivo administration of glucocorticoids in wild type but not in GILZ-KO neutrophils, suggesting the involvement of GILZ in TLR2 downregulation. Accordingly, the TLR2-associated anti-fungal activity of neutrophils was reduced by DEX treatment in wild type but not GILZ-KO neutrophils. Furthermore, GILZ did not interact with NF-κB but was found to bind with STAT5, a pivotal factor in the regulation of TLR2 expression. A similar modulation of TLR2 expression, impaired phagocytosis, and killing activity was observed in circulating human neutrophils treated in vitro with DEX. These results demonstrate that glucocorticoids reduce the ability of neutrophils to respond to infections by downregulating TLR2 via GILZ, thereby reducing critical functions.

Gene Expression and Resistance to Glucocorticoid-Induced Apoptosis in Acute Lymphoblastic Leukemia: A Brief Review and Update

BACKGROUND

Resistance to glucocorticoid (GC)-induced apoptosis in Acute Lymphoblastic Leukemia (ALL), is considered one of the major prognostic factors for the disease. Prednisolone is a corticosteroid and one of the most important agents in the treatment of acute lymphoblastic leukemia. The mechanics of GC resistance are largely unknown and intense ongoing research focuses on this topic.

AIM

The aim of the present study is to review some aspects of GC resistance in ALL, and in particular of Prednisolone, with emphasis on previous and present knowledge on gene expression and signaling pathways playing a role in the phenomenon.

METHODS

An electronic literature search was conducted by the authors from 1994 to June 2019. Original articles and systematic reviews selected, and the titles and abstracts of papers screened to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

RESULTS

Identification of gene targets responsible for glucocorticoid resistance may allow discovery of drugs, which in combination with glucocorticoids may increase the effectiveness of anti-leukemia therapies. The inherent plasticity of clinically evolving cancer justifies approaches to characterize and prevent undesirable activation of early oncogenic pathways.

CONCLUSION

Study of the pattern of intracellular signal pathway activation by anticancer drugs can lead to development of efficient treatment strategies by reducing detrimental secondary effects.

Glucocorticoid-Induced Leucine Zipper: A Promising Marker for Monitoring and Treating Sepsis

Sepsis is a clinical syndrome that resulting from a dysregulated inflammatory response to infection that leads to organ dysfunction. The dysregulated inflammatory response transitions from a hyper-inflammatory phase to a hypo-inflammatory or immunosuppressive phase. Currently, no phase-specific molecular-based therapies are available for monitoring the complex immune response and treating sepsis due to individual variations in the timing and overlap of the dysregulated immune response in most patients. Glucocorticoid-induced leucine zipper (GILZ), is broadly present in multiple tissues and circumvent glucocorticoid resistance (GCR) or unwanted side effects. Recently, the characteristics of GILZ downregulation during acute hyperinflammation and GILZ upregulation during the immunosuppressive phase in various inflammatory diseases have been well documented, and the protective effects of GILZ have gained attention in the field of sepsis. However, whether GILZ could be a promising candidate biomarker for monitoring and treating septic patients remains unknown. Here, we discuss the effect of GILZ in sepsis and sepsis-induced immunosuppression.

Exploiting the pro-resolving actions of glucocorticoid-induced proteins Annexin A1 and GILZ in infectious diseases

For decades, glucocorticoids (GC) have been used to treat several inflammatory conditions, including chronic and autoimmune diseases, due to their potent anti-inflammatory properties. In the context of infectious diseases, the use of GCs may be effective as adjuvant to antibiotic therapy by controlling excessive inflammatory responses resulting in better outcome in some cases. However, the use of GCs has been associated with a vast number of side effects, including increased probability of immunosuppression and consequent risk of opportunistic infection. Glucocorticoid-induced leucine zipper (GILZ) and Annexin A1 (AnxA1) are GC-induced proteins intrinsically involved with the anti-inflammatory functions of GCs without the associated adverse metabolic effects. Recent studies have shown that these GC-proteins exhibit pro-resolving effects. An essential characteristic of pro-resolving molecules is their ability to coordinate the resolution of inflammation and promote host defense in most experimental models of infection. Although the role of GILZ and AnxA1 in the context of infectious diseases remain to be better explored, herein we provide an overview of the emerging functions of these GC-proteins obtained from pre-clinical models of infectious diseases.

Vincristine and prednisone regulates cellular and exosomal miR-181a expression differently within the first time diagnosed and the relapsed leukemia B cells

We explored the effect of vincristine and prednisone on cellular and exosomal miR-181a expression in first time diagnosed leukemia and relapsed leukemia. Vincristine and prednisone induced apoptosis/pro-apoptotic genes in first time diagnosed leukemia, and suppressed the cellular and exosomal miR-181a expression. In contrast, vincristine and prednisone could not induce apoptosis/pro-apoptotic genes in relapsed leukemia, and could not change the expression of cellular or exosomal miR-181a. In conclusion, the non-suppressive nature of miR-181a in relapsed leukemia might contribute to the chemo-resistance and this suggests a potential role of miR-181a-inhibitor along with the chemotherapy in the treatment of relapsed leukemia.

Comparison of Serum Pharmacodynamic Biomarkers in Prednisone-Versus Deflazacort-Treated Duchenne Muscular Dystrophy Boys

Prednisone (Pred) and Deflazacort (Dfz) are commonly used glucocorticoids (GCs) for Duchenne muscular dystrophy (DMD) treatment and management. While GCs are known to delay the loss of ambulation and motor abilities, chronic use can result in onerous side effects, e.g., weight gain, growth stunting, loss of bone density, etc. Here, we use the CINRG Duchenne natural history study to gain insight into comparative safety of Pred versus Dfz treatment through GC-responsive pharmacodynamic (PD) biomarkers. Longitudinal trajectories of SOMAscan® protein data obtained on serum of DMD boys aged 4 to 10 (Pred: n = 7; Dfz: n = 8) were analyzed after accounting for age and time on treatment. Out of the pre-specified biomarkers, seventeen candidate proteins were differentially altered between the two drugs (p < 0.05). These include IGFBP-2 and AGER associated with diabetes complications, and MMP-3 associated with extracellular remodeling. As a follow-up, IGFBP-2, MMP-3, and IGF-I were quantified with an ELISA using a larger sample size of DMD biosamples (Dfz: n = 17, Pred: n = 12; up to 76 sera samples) over a longer treatment duration. MMP-3 and IGFBP-2 validated the SOMAscan® signal, however, IGF-I did not. This study identified GC-responsive biomarkers, some associated with safety, that highlight differential PD response between Dfz and Pred.

Latest perspectives on glucocorticoid-induced apoptosis and resistance in lymphoid malignancies

Glucocorticoids are essential drugs in the treatment protocols of lymphoid malignancies. These steroidal hormones trigger apoptosis of the malignant cells by binding to the glucocorticoid receptor (GR), which is a member of the nuclear receptor superfamily. Long term glucocorticoid treatment is limited by two major problems: the development of glucocorticoid-related side effects, which hampers patient quality of life, and the emergence of glucocorticoid resistance, which is a gradual process that is inevitable in many patients. This emphasizes the need to reevaluate and optimize the widespread use of glucocorticoids in lymphoid malignancies. To achieve this goal, a deep understanding of the mechanisms governing glucocorticoid responsiveness is required, yet, a recent comprehensive overview is currently lacking. In this review, we examine how glucocorticoids mediate apoptosis by detailing GR's genomic and non-genomic action mechanisms in lymphoid malignancies. We continue with a discussion of the glucocorticoid-related problems and how these are intertwined with one another. We further zoom in on glucocorticoid resistance by critically analyzing the plethora of proposed mechanisms and highlighting therapeutic opportunities that emerge from these studies. In conclusion, early detection of glucocorticoid resistance in patients remains an important challenge as this would result in a timelier treatment reorientation and reduced glucocorticoid-instigated side effects.

Glucocorticoid-induced leucine zipper modulates macrophage polarization and apoptotic cell clearance

Macrophages are professional phagocytes that display remarkable plasticity, with a range of phenotypes that can be broadly characterized by the M1/M2 dichotomy. Glucocorticoid (GC)-induced leucine zipper (GILZ) is a protein known to mediate anti-inflammatory and some pro-resolving actions, including as neutrophil apoptosis. However, the role of GILZ in key macrophage function is not well understood. Here, we investigated the role of GILZ on macrophage reprogramming and efferocytosis. Using murine bone-marrow-derived macrophages (BMDMs), we found that GILZ was expressed in naive BMDMs and exhibited increased expression in M2-like macrophages (IL4-differentiated). M1-like macrophages (IFN/LPS-differentiated) from GILZ^-/- mice showed higher expression of the M1 markers CD86, MHC class II, iNOS, IL-6 and TNF-α, associated with increased levels of phosphorylated STAT1 and lower IL-10 levels, compared to M1-differentiated cells from WT mice. There were no changes in the M2 markers CD206 and arginase-1 in macrophages from GILZ^-/- mice differentiated with IL-4, compared to cells from WT animals. Treatment of M1-like macrophages with TAT-GILZ, a cell-permeable GILZ fusion protein, decreased the levels of CD86 and MHC class II in M1-like macrophages without modifying CD206 levels in M2-like macrophages. In line with the in vitro data, increased numbers of M1-like macrophages were found into the pleural cavity of GILZ^-/- mice after LPS-injection, compared to WT mice. Moreover, efferocytosis was defective in the context of GILZ deficiency, both in vitro and in vivo. Conversely, treatment of LPS-injected mice with TAT-GILZ promoted inflammation resolution, associated with lower numbers of M1-like macrophages and increased efferocytosis. Collectively, these data indicate that GILZ is a regulator of important macrophage functions, contributing to macrophage reprogramming and efferocytosis, both key steps for the resolution of inflammation.

The glucocorticoid-induced leucine zipper mediates statin-induced muscle damage

Statins, the most prescribed class of drugs for the treatment of hypercholesterolemia, can cause muscle-related adverse effects. It has been shown that the glucocorticoid-induced leucine zipper (GILZ) plays a key role in the anti-myogenic action of dexamethasone. In the present study, we aimed to evaluate the role of GILZ in statin-induced myopathy. Statins induced GILZ expression in C2C12 cells, primary murine myoblasts/myotubes, primary human myoblasts, and in vivo in zebrafish embryos and human quadriceps femoris muscle. Gilz induction was mediated by FOXO3 activation and binding to the Gilz promoter, and could be reversed by the addition of geranylgeranyl, but not farnesyl, pyrophosphate. Atorvastatin decreased Akt phosphorylation and increased cleaved caspase-3 levels in myoblasts. This effect was reversed in myoblasts from GILZ knockout mice. Similarly, myofibers isolated from knockout animals were more resistant toward statin-induced cell death than their wild-type counterparts. Statins also impaired myoblast differentiation, and this effect was accompanied by GILZ induction. The in vivo relevance of our findings was supported by the observation that gilz overexpression in zebrafish embryos led to impaired embryonic muscle development. Taken together, our data point toward GILZ as an essential mediator of the molecular mechanisms leading to statin-induced muscle damage.

Overexpression of GILZ in macrophages limits systemic inflammation while increasing bacterial clearance in sepsis in mice

Studies support the beneficial effects of glucocorticoids (GCs) during septic shock, steering research toward the potential role of GC-induced proteins in controlling excessive inflammatory responses. GILZ is a glucocorticoid-induced protein involved in the anti-inflammatory effects of GCs. We investigated whether the overexpression of GILZ specifically limited to monocytes and macrophages (M/M) alone could control inflammation, thus improving the outcome of septic shock in animal models. We also monitored the expression of GILZ in M/M from septic mice and septic-shock patients. M/M from patients and septic mice displayed significantly lower expression of GILZ than those isolated from controls. Furthermore, transgenic mice (Tg-mice) experiencing sepsis, with increased expression of GILZ restricted to M/M, showed lower frequencies of inflammatory monocytes than their littermates and lower plasma levels of inflammatory cytokines. Tg-mice also had lower blood bacterial counts. We further established that the upregulation of GILZ in M/M enhanced their phagocytic capacity in in vivo assays. The increase of GILZ in M/M was also sufficient to improve the survival rates of septic mice. These results provide evidence for a central role of both GILZ and M/M in the pathophysiology of septic shock and a possible clue for the modulation of inflammation in this disease.

Nrf2 downregulates zymosan-induced neutrophil activation and modulates migration

Polymorphonuclear neutrophils (PMNs) are the first line of defense against pathogens and their activation needs to be tightly regulated in order to limit deleterious effects. Nrf2 (Nuclear factor (erythroïd-derived 2)-like 2) transcription factor regulates oxidative stress and/or represses inflammation in various cells such as dendritic cells or macrophages. However, its involvement in PMN biology is still unclear. Using Nrf2 KO mice, we thus aimed to investigate the protective role of Nrf2 in various PMN functions such as oxidative burst, netosis, migration, cytokine production and phagocytosis, mainly in response to zymosan. We found that zymosan induced Nrf2 accumulation in PMNs leading to the upregulation of some target genes including Hmox-1, Nqo1 and Cat. Nrf2 was able to decrease zymosan-induced PMN oxidative burst; sulforaphane-induced Nrf2 hyperexpression confirmed its implication. Tnfα, Ccl3 and Cxcl2 gene transcription was decreased in zymosan-stimulated Nrf2 KO PMNs, suggesting a role for Nrf2 in the regulation of proinflammatory cytokine production. However, Nrf2 was not involved in phagocytosis. Finally, spontaneous migration of Nrf2 KO PMNs was lower than that of WT PMNs. Moreover, in response to low concentrations of CXCL2 or CXCL12, Nrf2 KO PMN migration was decreased despite similar CXCR2 and CXCR4 expression and ATP levels in PMNs from both genotypes. Nrf2 thus seems to be required for an optimal migration. Altogether these results suggest that Nrf2 has a protective role in several PMN functions. In particular, it downregulates their activation in response to zymosan and is required for an adequate migration.

Could GILZ Be the Answer to Glucocorticoid Toxicity in Lupus?

Glucocorticoids (GC) are used globally to treat autoimmune and inflammatory disorders. Their anti-inflammatory actions are mainly mediated via binding to the glucocorticoid receptor (GR), creating a GC/GR complex, which acts in both the cytoplasm and nucleus to regulate the transcription of a host of target genes. As a result, signaling pathways such as NF-κB and AP-1 are inhibited, and cell activation, differentiation and survival and cytokine and chemokine production are suppressed. However, the gene regulation by GC can also cause severe side effects in patients. Systemic lupus erythematosus (SLE or lupus) is a multisystem autoimmune disease, characterized by a poorly regulated immune response leading to chronic inflammation and dysfunction of multiple organs, for which GC is the major current therapy. Long-term GC use, however, can cause debilitating adverse consequences for patients including diabetes, cardiovascular disease and osteoporosis and contributes to irreversible organ damage. To date, there is no alternative treatment which can replicate the rapid effects of GC across multiple immune cell functions, effecting disease control during disease flares. Research efforts have focused on finding alternatives to GC, which display similar immunoregulatory actions, without the devastating adverse metabolic effects. One potential candidate is the glucocorticoid-induced leucine zipper (GILZ). GILZ is induced by low concentrations of GC and is shown to mimic the action of GC in several inflammatory processes, reducing immunity and inflammation in in vitro and in vivo studies. Additionally, GILZ has, similar to the GC-GR complex, the ability to bind to both NF-κB and AP-1 as well as DNA directly, to regulate immune cell function, while potentially lacking the GC-related side effects. Importantly, in SLE patients GILZ is under-expressed and correlates negatively with disease activity, suggesting an important regulatory role of GILZ in SLE. Here we provide an overview of the actions and use of GC in lupus, and discuss whether the regulatory mechanisms of GILZ could lead to the development of a novel therapeutic for lupus. Increased understanding of the mechanisms of action of GILZ, and its ability to regulate immune events leading to lupus disease activity has important clinical implications for the development of safer anti-inflammatory therapies.

How Glucocorticoids Affect the Neutrophil Life

Glucocorticoids are hormones that regulate several functions in living organisms and synthetic glucocorticoids are the most powerful anti-inflammatory pharmacological tool that is currently available. Although glucocorticoids have an immunosuppressive effect on immune cells, they exert multiple and sometimes contradictory effects on neutrophils. From being extremely sensitive to the anti-inflammatory effects of glucocorticoids to resisting glucocorticoid-induced apoptosis, neutrophils are proving to be more complex than they were earlier thought to be. The aim of this review is to explain these complex pathways by which neutrophils respond to endogenous or to exogenous glucocorticoids, both under physiological and pathological conditions.

Glucocorticoid-Induced Leucine Zipper Promotes Neutrophil and T-Cell Polarization with Protective Effects in Acute Kidney Injury

The glucocorticoid-induced leucine zipper (GILZ) mediates anti-inflammatory effects of glucocorticoids. Acute kidney injury (AKI) mobilizes immune/inflammatory mechanisms, causing tissue injury, but the impact of GILZ in AKI is not known. Neutrophils play context-specific proinflammatory [type 1 neutrophil (N1)] and anti-inflammatory [type 2 neutrophil (N2)] functional roles. Also, regulatory T lymphocytes (Tregs) and regulatory T-17 (Treg17) cells exert counterinflammatory effects, including the suppression of effector T lymphocytes [e.g., T-helper (Th) 17 cells]. Thus, utilizing cell preparations of mice kidneys subjected to AKI or sham operation, we determined the effects of GILZ on T cells and neutrophil subtypes in the context of its renoprotective effect; these studies used the transactivator of transcription (TAT)-GILZ or the TAT peptide. AKI increased N1 and Th-17 cells but reduced N2, Tregs, and Treg17 cells in association with increased interleukin (IL)-17⁺ but reduced IL-10⁺ cells accompanied with the disruption of mitochondrial membrane potential (ψ _m) and increased apoptosis/necrosis compared with sham kidneys. TAT-GILZ, compared with TAT, treatment reduced N1 and Th-17 cells but increased N2 and Tregs, without affecting Treg17 cells, in association with a reduction in IL-17⁺ cells but an increase in IL-10⁺ cells; TAT-GILZ caused less disruption of ψ _m and reduced cell death in AKI. Importantly, TAT-GILZ increased perfusion of the ischemic-reperfused kidney but reduced tissue edema compared with TAT. Utilizing splenic T cells and bone marrow-derived neutrophils, we further showed marked reduction in the proliferation of Th cells in response to TAT-GILZ compared with response to TAT. Collectively, the results indicate that GILZ exerts renoprotection accompanied by the upregulation of the regulatory/suppressive arm of immunity in AKI, likely via regulating cross talk between T cells and neutrophils.

Transcriptome reprogramming by cancer exosomes: identification of novel molecular targets in matrix and immune modulation

BACKGROUND

Exosomes are extracellular vesicles released by almost all cell types, including cancer cells, into bodily fluids such as saliva, plasma, breast milk, semen, urine, cerebrospinal fluid, amniotic fluid, synovial fluid and sputum. Their key function being intercellular communication with both neighbouring as well as distant cells. Cancer exosomes have been shown to regulate organ-specific metastasis. However, little is known about the functional differences and molecular consequences of normal cells responding to exosomes derived from normal cells compared to those derived from cancer cells.

METHODS

Here, we characterised and compared the transcriptome profiles of primary human normal oral keratinocytes (HNOK) in response to exosomes isolated from either primary HNOK or head and neck squamous cell carcinoma (HNSCC) cell lines.

RESULTS

In recipient HNOK cells, we found that regardless of normal or cancer derived, exosomes altered molecular programmes involved in matrix modulation (MMP9), cytoskeletal remodelling (TUBB6, FEZ1, CCT6A), viral/dsRNA-induced interferon (OAS1, IFI6), anti-inflammatory (TSC22D3), deubiquitin (OTUD1), lipid metabolism and membrane trafficking (BBOX1, LRP11, RAB6A). Interestingly, cancer exosomes, but not normal exosomes, modulated expression of matrix remodelling (EFEMP1, DDK3, SPARC), cell cycle (EEF2K), membrane remodelling (LAMP2, SRPX), differentiation (SPRR2E), apoptosis (CTSC), transcription/translation (KLF6, PUS7). We have also identified CEP55 as a potential cancer exosomal marker.

CONCLUSIONS

In conclusion, both normal and cancer exosomes modulated unique gene expression pathways in normal recipient cells. Cancer cells may exploit exosomes to confer transcriptome reprogramming that leads to cancer-associated pathologies such as angiogenesis, immune evasion/modulation, cell fate alteration and metastasis. Molecular pathways and biomarkers identified in this study may be clinically exploitable for developing novel liquid-biopsy based diagnostics and immunotherapies.

Dexamethasone Stimulates Hepatitis B Virus (HBV) Replication Through Autophagy

Background

Reactivation of hepatitis B virus (HBV) is a fatal complication of chemotherapy. Occult HBV infection might be reactivated in patients undergoing chemotherapy or immunosuppression. However, the mechanism of HBV reactivation induced by chemotherapy or immunosuppression remains unclear.

Material/Methods

HepG2.2.15 cells were treated with an autophagy inducer (rapamycin), an inhibitor (3-methyladenine, 3-MA), and dexamethasone. Autophagosomes were observed by a transmission electron microscope (TEM). LC3-I, LC3-II, and P62 were analyzed by western blot. HBV replicative intermediates were detected by southern blot. HBV DNA expression was quantitated with real-time polymerase chain reaction (PCR). The level of HBV surface antigen (HBsAg) in culture medium was examined by ELISA.

Results

In this study, we find that dexamethasone stimulates HBV replication and protein expression by inducing autophagy in HepG2.2.15 cells. In contrast, autophagy inhibitor (3-MA) abrogates HBsAg secretion stimulated by dexamethasone.

Conclusions

Our results suggest that dexamethasone stimulates HBV replication through autophagy. This might provide a novel insight into the mechanism of glucocorticoid-mediated HBV reactivation through autophagy, which might be a new therapeutic target.

A dual role for glucocorticoid-induced leucine zipper in glucocorticoid function: tumor growth promotion or suppression?

Glucocorticoids (GCs), important therapeutic tools to treat inflammatory and immunosuppressive diseases, can also be used as part of cancer therapy. In oncology, GCs are used as anticancer drugs for lymphohematopoietic malignancies, while in solid neoplasms primarily to control the side effects of chemo/radiotherapy treatments. The molecular mechanisms underlying the effects of GCs are numerous and often overlapping, but not all have been elucidated. In normal, cancerous, and inflammatory tissues, the response to GCs differs based on the tissue type. The effects of GCs are dependent on several factors: the tumor type, the GC therapy being used, the expression level of the glucocorticoid receptor (GR), and the presence of any other stimuli such as signals from immune cells and the tumor microenvironment. Therefore, GCs may either promote or suppress tumor growth via different molecular mechanisms. Stress exposure results in dysregulation of the hypothalamic-pituitary-adrenal axis with increased levels of endogenous GCs that promote tumorigenesis, confirming the importance of GCs in tumor growth. Most of the effects of GCs are genomic and mediated by the modulation of GR gene transcription. Moreover, among the GR-induced genes, glucocorticoid-induced leucine zipper (GILZ), which was cloned and characterized primarily in our laboratory, mediates many GC anti-inflammatory effects. In this review, we analyzed the possible role for GILZ in the effects GCs have on tumors cells. We also suggest that GILZ, by affecting the immune system, tumor microenvironment, and directly cancer cell biology, has a tumor-promoting function. However, it may also induce apoptosis or decrease the proliferation of cancer cells, thus inhibiting tumor growth. The potential therapeutic implications of GILZ activity on tumor cells are discussed here.

Role of the glucocorticoid-induced leucine zipper gene in dexamethasone-induced inhibition of mouse neutrophil migration via control of annexin A1 expression

The glucocorticoid-induced leucine zipper (GILZ) gene is a pivotal mediator of the anti-inflammatory effects of glucocorticoids (GCs) that are known to regulate the function of both adaptive and innate immunity cells. Our aim was to investigate the role of GILZ in GC-induced inhibition of neutrophil migration, as this role has not been investigated before. We found that GILZ expression was induced by dexamethasone (DEX), a synthetic GC, in neutrophils, and that it regulated migration of these cells into inflamed tissues under DEX treatment. Of note, inhibition of neutrophil migration was not observed in GILZ-knockout mice with peritonitis that were treated by DEX. This was because DEX was unable to up-regulate annexin A1 (Anxa1) expression in the absence of GILZ. Furthermore, we showed that GILZ mediates Anxa1 induction by GCs by transactivating Anxa1 expression at the promoter level via binding with the transcription factor, PU.1. The present findings shed light on the role of GILZ in the mechanism of induction of Anxa1 by GCs. As Anxa1 is an important protein for the resolution of inflammatory response, GILZ may represent a new pharmacologic target for treatment of inflammatory diseases.-Ricci, E., Ronchetti, S., Pericolini, E., Gabrielli, E., Cari, L., Gentili, M., Roselletti, E., Migliorati, G., Vecchiarelli, A., Riccardi, C. Role of the glucocorticoid-induced leucine zipper gene in dexamethasone-induced inhibition of mouse neutrophil migration via control of annexin A1 expression.

Neutrophil expression of glucocorticoid-induced leucine zipper (GILZ) anti-inflammatory protein is associated with acute respiratory distress syndrome severity

Background

Glucocorticoid-induced leucine zipper (GILZ) is a potent anti-inflammatory protein involved in neutrophil apoptosis and the resolution of inflammation. Given the numerous pathophysiologic roles of neutrophils in the acute respiratory distress syndrome (ARDS), we postulated that neutrophil GILZ expression might be induced during ARDS, to modulate the inflammatory process and participate in lung repair.

Methods

This single-center, prospective, observational cohort study took place in the surgical intensive care unit of Bichat Hospital (Paris, France) and involved 17 ARDS patients meeting the Berlin criteria at inclusion, and 14 ventilated controls without ARDS. Serial blood samples were obtained every 2 days until extubation or death (from 1 to 9 samples per patient). GILZ protein and gene expression was quantified in blood neutrophils, along with markers of inflammation (CRP, extracellular DNA) or its resolution (Annexin A1).

Results

Neutrophil GILZ expression was detected at the transcriptional and/or translational level in 9/17 ARDS patients (in particular 7/10 severe ARDS) and in 2/14 ventilated controls. The highest mRNA levels were observed in the most severely ill patients (p < 0.028). GILZ was expressed in about ¾ of the corticosteroid-treated patients and its expression could also occur independently of corticosteroids, suggesting that inflammatory signals may also induce neutrophil GILZ expression in vivo.

Conclusions

In this pilot study, we show for the first time that blood neutrophils from patients with ARDS can express GILZ, in keeping with an anti-inflammatory and regulatory endogenous role of GILZ in humans. Contrary to some markers of inflammation or its resolution, the levels of gilz gene expression were related to ARDS severity.