Sulfasalazine sensitises human monocytic/macrophage cells for glucocorticoids by upregulation of glucocorticoid receptor alpha and glucocorticoid induced apoptosis

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

Signals and Mechanisms Regulating Monocyte and Macrophage Activation in the Pathogenesis of Juvenile Idiopathic Arthritis

Monocytes (Mos) and macrophages (Mφs) are key players in the innate immune system and are critical in coordinating the initiation, expansion, and regression of many autoimmune diseases. In addition, they display immunoregulatory effects that impact inflammation and are essential in tissue repair and regeneration. Juvenile idiopathic arthritis (JIA) is an umbrella term describing inflammatory joint diseases in children. Accumulated evidence suggests a link between Mo and Mφ activation and JIA pathogenesis. Accordingly, topics regarding the signals and mechanisms regulating Mo and Mφ activation leading to pathologies in patients with JIA are of great interest. In this review, we critically summarize recent advances in the understanding of how Mo and Mφ activation is involved in JIA pathogenesis and focus on the signaling pathways and mechanisms participating in the related cell activation processes.

Immune Modulation as Adjunctive Therapy for Pneumocystis pneumonia

Pneumocystis is an opportunistic fungal respiratory pathogen that causes life-threatening pneumonia (Pcp) in patients suffering from defects in cell-mediated immunity, including those with acquired immunodeficiency syndrome (AIDS) and immunosuppression secondary to chemotherapy or organ transplantation. Despite major advances in health care, the mortality associated with Pcp has changed little over the past 25  years. Pcp remains a leading cause of death among HIV infected patients, with mortality rates of 50% or higher for patients developing severe Pcp. In addition, as more potent immunosuppressive therapies are developed for chronic inflammatory diseases, more cases of Pcp are occurring in non-HIV patients and in previously unreported clinical settings. These features highlight the importance of developing a better understanding of the pathogenesis of this disease, and the need to search for new therapeutic strategies to improve the outcome of Pcp patients. Immune-mediated inflammatory responses play an important role in the pathogenesis of Pcp, and may be even more significant in determining the outcome of Pcp than direct damage due to the organism itself. In this review we will summarize the immunopathogenic mechanisms that contribute to Pcp-associated lung injury, and discuss the potential to target these pathways for adjunctive immune modulation therapy for Pcp.

Overexpression of the IGF2-mRNA binding protein p62 in transgenic mice induces a steatotic phenotype

BACKGROUND & AIMS

The insulin-like growth-factor 2 (IGF2) mRNA binding protein p62 is highly expressed in hepatocellular carcinoma tissue. Still, its potential role in liver disease is largely unknown. In this study, we investigated pathophysiological implications of p62 overexpression in mice.

METHODS

We generated mice overexpressing p62 under a LAP-promotor. mRNA expression levels and stability were examined by real-time RT-PCR. Allele-specific expression of Igf2 and H19 was assessed after crossing mice with SD7 animals. The Igf2 downstream mediators pAKT and PTEN were determined by Western blot.

RESULTS

Hepatic p62 overexpression neither induced inflammatory processes nor liver damage. However, 2.5week old transgenic animals displayed a steatotic phenotype and improved glucose tolerance. p62 overexpression induced the expression of the imprinted genes Igf2 and H19 and their transcriptional regulator Aire (autoimmune regulator). Neither monoallelic expression nor mRNA stability of Igf2 and H19 was affected. Investigating Igf2 downstream signalling pathways showed increased AKT activation and attenuated PTEN expression.

CONCLUSIONS

The induction of a steatotic phenotype implies that p62 plays a role in hepatic pathophysiology.

Sulphasalazine accelerates apoptosis in neutrophils exposed to immune complex: Role of caspase pathway

1. Neutrophils release several histotoxic molecules that cause tissue injury. Neutrophil apoptosis is a crucial process that governs the persistence of inflammatory disorders and tissue damage. Thus, in the present study, we investigated whether the anti-inflammatory drug sulphasalazine (SSZ) affects neutrophil apoptosis in the presence of insoluble immune complex (IC). 2. Neutrophils were obtained from healthy donors. Neutrophils were resuspended in incubation medium and incubated for 2-12 h with or without 10, 30 or 100 micromol/L SSZ and 25 microg/mL IC. In some experiments, cells were co-incubated with 20 micromol/L Z-IETD-fmk (a caspase 8 inhibitor) or 20 micromol/L Z-LEHD-fmk (a caspase 9 inhibitor). Apoptosis was evaluated morphologically on cytological preparations stained with May-Grünwald-Giemsa as well as by flow cytometry analysis of annexin V and propidium iodide staining. Caspase 3 activity was determined spectrophotometrically. 3. At 100 micromol/L, SSZ significantly accelerated IC-induced neutrophil apoptosis. Treatment of neutrophils with 20 micromol/L of the caspase 8 or 9 inhibitors Z-IETD-fmk or Z-LEHD-fmk, respectively, demonstrated that the SSZ-induced pro-apoptotic effect was mediated by a caspase 8- but not caspase 9-dependent pathway. The caspase 3 activity assay showed that treatment with 100 micromol/L SSZ increased caspase 3 activation. 4. In conclusion, the results of the present study indicate that it is possible that the molecular mechanism underlying SSZ protection against neutrophil-mediated tissue injury inflammatory disorders, such as rheumatoid arthritis and inflammatory bowel diseases, involves a caspase 8-dependent pathway.

The inhibitory Fc gamma IIb receptor dampens TLR4-mediated immune responses and is selectively up-regulated on dendritic cells from rheumatoid arthritis patients with quiescent disease

Rheumatoid arthritis (RA) is a common autoimmune disease leading to profound disability and premature death. Although a role for FcgammaRs and TLRs is accepted, their precise involvement remains to be elucidated. FcgammaRIIb is an inhibitory FcR important in the maintenance of tolerance. We hypothesized that the inhibitory FcgammaRIIb inhibits TLR responses on monocyte-derived dendritic cells (DC) and serves as a counterregulatory mechanism to dampen inflammation, and we surmised that this mechanism might be defective in RA. The expression of the inhibitory FcgammaRIIb was found to be significantly higher on DCs from RA patients having low RA disease activity in the absence of treatment with antirheumatic drugs. The expression of activating FcgammaRs was similarly distributed among all RA patients and healthy controls. Intriguingly, only DCs with a high expression of FcgammaRIIb were able to inhibit TLR4-mediated secretion of proinflammatory cytokines when stimulated with immune complexes. In addition, when these DCs were coincubated with the combination of a TLR4 agonist and immune complexes, a markedly inhibited T cell proliferation was apparent, regulatory T cell development was promoted, and T cells were primed to produce high levels of IL-13 compared with stimulation of the DCs with the TLR4 agonist alone. Blocking FcgammaRIIb with specific Abs fully abrogated these effects demonstrating the full dependence on the inhibitory FcgammaRIIb in the induction of these phenomena. This TLR4-FcgammaRIIb interaction was shown to dependent on the PI3K and Akt pathway.

Gene expression profiling of leukemic cells and primary thymocytes predicts a signature for apoptotic sensitivity to glucocorticoids

Background

Glucocorticoids (GC's) play an integral role in treatment strategies designed to combat various forms of hematological malignancies. GCs also are powerful inhibitors of the immune system, through regulation of appropriate cytokines and by causing apoptosis of immature thymocytes. By activating the glucocorticoid receptor (GR), GCs evoke apoptosis through transcriptional regulation of a complex, interactive gene network over a period of time preceding activation of the apoptotic enzymes. In this study we used microarray technology to determine whether several disparate types of hematologic cells, all sensitive to GC-evoked apoptosis, would identify a common set of regulated genes. We compared gene expression signatures after treatment with two potent synthetic GCs, dexamethasone (Dex) and cortivazol (CVZ) using a panel of hematologic cells. Pediatric CD4+/CD8+ T-cell leukemia was represented by 3 CEM clones: two sensitive, CEM-C7–14 and CEM-C1–6, and one resistant, CEM-C1–15, to Dex. CEM-C1–15 was also tested when rendered GC-sensitive by several treatments. GC-sensitive pediatric B-cell leukemia was represented by the SUP-B15 line and adult B-cell leukemia by RS4;11 cells. Kasumi-1 cells gave an example of the rare Dex-sensitive acute myeloblastic leukemia (AML). To test the generality of the correlations in malignant cell gene sets, we compared with GC effects on mouse non-transformed thymocytes.

Results

We identified a set of genes regulated by GCs in all GC-sensitive malignant cells. A portion of these were also regulated in the thymocytes. Because we knew that the highly Dex-resistant CEM-C1–15 cells could be killed by CVZ, we tested these cells with the latter steroid and again found that many of the same genes were now regulated as in the inherently GC-sensitive cells. The same result was obtained when we converted the Dex-resistant clone to Dex-sensitive by treatment with forskolin (FSK), to activate the adenyl cyclase/protein kinase A pathway (PKA).

Conclusion

Our results have identified small sets of genes that correlate with GC-sensitivity in cells from several hematologic malignancies. Some of these are also regulated in normal mouse thymocytes.