Effects of representative glucocorticoids on TNFα- and CD40L-induced NF-κB activation in sensor cells

Dexamethasone in the Treatment of COVID-19: Primus Inter Pares?

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly spread globally, becoming a huge public health challenge. Even though the vast majority of patients are asymptomatic, some patients present with pneumonia, acute respiratory distress syndrome (ARDS), septic shock, and death. It has been shown in several studies that the severity and clinical outcomes are related to dysregulated antiviral immunity and enhanced and persistent systemic inflammation. Corticosteroids have been used for the treatment of COVID-19 patients, as they are reported to elicit benefits by reducing lung inflammation and inflammation-induced lung injury. Dexamethasone has gained a major role in the therapeutic algorithm of patients with COVID-19 pneumonia requiring supplemental oxygen or on mechanical ventilation. Its wide anti-inflammatory action seems to form the basis for its beneficial action, taming the overwhelming "cytokine storm". Amid a plethora of scientific research on therapeutic options for COVID-19, there are still unanswered questions about the right timing, right dosing, and right duration of the corticosteroid treatment. The aim of this review article was to summarize the data on the dexamethasone treatment in COVID-19 and outline the clinical considerations of corticosteroid therapy in these patients.

[The CD40-CD40L axis: Current and future implications in clinical immunology]

The CD40-CD40 ligand (CD40L) pathway is a backbone of communication between cells of the immune system. It makes it possible to generate a proinflammatory signal and thus participates in the pathogenesis of dysimmune diseases, transplant rejection and atherosclerosis. Because of this therapeutic target of choice, several generations of anti-CD40L monoclonal antibodies have emerged since the 1990s. The first generation of antibodies was responsible for thromboembolic toxicity for which the mechanisms are starting to be defined. New generations of antibodies were designed to overcome this toxicity and are still being developed in lupus, rheumatoid arthritis, Sjogren's syndrome or immunologic thrombocytopenia. In addition to these targeted therapies, there are data suggesting the impact of several drugs among molecules used in cardiology and clinical immunology on the level of CD40L. The objective of this review is to recall the clinical issues related to the CD40-CD40L axis and to present current or future treatments that block CD40L which would allow clinicians to diversify their options for managing dysimmune diseases.

Ginsenoside compound K- a potential drug for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disease, if prescription of effective delayed, the articular disturbances may lead to disability. Ginsenoside compound K (GCK) is the main degradation product of oral ginsenosides in the human intestine. Numerous researches in vitro and in vivo have recorded the anti-arthritic effect of GCK, we discuss the mechanisms from the following three aspects, including anti-inflammatory, immune-regulatory, and bone-protective, respectively, in this review, and the anti-arthritic mechanism of GCK may be related to the effect on TNF-α-TNFR2, glucocorticoid receptor (GR) and β-arrestin1/2. We also describe the anti-anemia effect of GCK to open the possibility that GCK can be used as an effective disease-modifying anti-rheumatic drug (DMARD).

ORMDL3 modulates airway epithelial cell repair in children with asthma under glucocorticoid treatment via regulating IL-33

BACKGROUND

Study found that glucocorticoids, as first-line treatments for asthma, fails to prevent asthma recurrence. Orosomucoid-like (ORMDL) 3 is associated to childhood asthma onset and involved in the inflammation and repair of airway epithelium. We explored the functional role of ORMDL3 in glucocorticoid treatment for childhood asthma.

METHODS

Mice were sensitized with Ovalbumin (OVA) and treated with Dexamethasone (Dex), followed by OVA challenge to establish a mouse model of asthma. Histopathological changes in lung tissues were observed by hematoxylin-eosin and masson staining. Human bronchial epithelial (16HBE-14°) cells were transfected with ORMDL3 overexpression plasmid and siRNA-interleukin (IL)-33 alone or in combination, followed by Dex. Cell viability was measured by MTT assay. Cell migration was evaluated by wound healing assay. The expressions of E-cadherin and Vimentin and the activation of NF-κB and MAPK/ERK in 16HBE-14° cells were assessed by Western blot. The expressions of ORMDL3 and IL-33 in lung tissues and 16HBE-14° cells were analyzed by qRT-PCR or Western blot.

RESULTS

Dex treatment alleviated the histopathological abnormality and reversed the overexpressions of ORMDL3 and IL-33 in the lung tissues of asthmatic mice. Overexpressed ORMDL3 enhanced migration and viability, decreased E-cadherin level, increased the levels of IL-33 and Vimentin, and promoted the phosphorylation of NF-κB and MAPK/ERK in Dex-treated 16HBE-14° cells, thus reversing the effect of Dex treatment. However, siRNA-IL-33 inhibited viability and migration, increased E-cadherin level, decreased Vimentin level, and suppressed the phosphorylation of NF-κB and MAPK/ERK, thus reversing the effect of overexpressed ORMDL3 in Dex-treated 16HBE-14° cells.

CONCLUSION

ORMDL3 overexpression helped airway epithelial cellrepairin asthma via regulating IL-33 expression.

Design, Synthesis, and Evaluation of Novel Immunomodulatory Small Molecules Targeting the CD40⁻CD154 Costimulatory Protein-Protein Interaction

We report the design, synthesis, and testing of novel small-molecule compounds targeting the CD40⁻CD154 (CD40L) costimulatory interaction for immunomodulatory purposes. This protein-protein interaction (PPI) is a TNF-superfamily (TNFSF) costimulatory interaction that is an important therapeutic target since it plays crucial roles in the activation of T cell responses, and there is resurgent interest in its modulation with several biologics in development. However, this interaction, just as all other PPIs, is difficult to target by small molecules. Following up on our previous work, we have now identified novel compounds such as DRI-C21091 or DRI-C21095 that show activity (IC50) in the high nanomolar to low micromolar range in the binding inhibition assay and more than thirty-fold selectivity versus other TNFSF PPIs including OX40⁻OX40L, BAFFR-BAFF, and TNF-R1-TNFα. Protein thermal shift (differential scanning fluorimetry) assays indicate CD154 and not CD40 as the binding partner. Activity has also been confirmed in cell assays and in a mouse model (alloantigen-induced T cell expansion in a draining lymph node). Our results expand the chemical space of identified small-molecule CD40⁻CD154 costimulatory inhibitors and provide lead structures that have the potential to be developed as orally bioavailable immunomodulatory therapeutics that are safer and less immunogenic than corresponding biologics.

Aldo-Keto Reductases: Multifunctional Proteins as Therapeutic Targets in Diabetes and Inflammatory Disease

Aldose reductase (AR) is an NADPH-dependent aldo-keto reductase that has been shown to be involved in the pathogenesis of several blinding diseases such as uveitis, diabetic retinopathy (DR) and cataract. However, possible mechanisms linking the action of AR to these diseases are not well understood. As DR and cataract are among the leading causes of blindness in the world, there is an urgent need to explore therapeutic strategies to prevent or delay their onset. Studies with AR inhibitors and gene-targeted mice have demonstrated that the action of AR is also linked to cancer onset and progression. In this review we examine possible mechanisms that relate AR to molecular signaling cascades and thus explain why AR inhibition is an effective strategy against colon cancer as well as diseases of the eye such as uveitis, cataract, and retinopathy.

Small-Molecule Inhibitors of the CD40-CD40L Costimulatory Protein-Protein Interaction

Costimulatory interactions are required for T cell activation and development of an effective immune response; hence, they are valuable therapeutic targets for immunomodulation. However, they, as all other protein-protein interactions, are difficult to target by small molecules. Here, we report the identification of novel small-molecule inhibitors of the CD40-CD40L interaction designed starting from the chemical space of organic dyes. For the most promising compounds such as DRI-C21045, activity (IC50) in the low micromolar range has been confirmed in cell assays including inhibition of CD40L-induced activation in NF-κB sensor cells, THP-1 myeloid cells, and primary human B cells as well as in murine allogeneic skin transplant and alloantigen-induced T cell expansion in draining lymph node experiments. Specificity versus other TNF-superfamily interactions (TNF-R1-TNF-α) and lack of cytotoxicity have also been confirmed at these concentrations. These novel compounds provide proof-of-principle evidence for the possibility of small-molecule inhibition of costimulatory protein-protein interactions, establish the structural requirements needed for efficient CD40-CD40L inhibition, and serve to guide the search for such immune therapeutics.

Laryngeal mucus hypersecretion is exacerbated after smoking cessation and ameliorated by glucocorticoid administration

INTRODUCTION

The mechanisms underlying the effects of cigarette smoke and smoking cessation on respiratory secretion, especially in the larynx, remain unclear.

OBJECTIVES

The aims of this study were to determine the effects of cigarette smoke and smoking cessation on laryngeal mucus secretion and inflammation, and to investigate the effects of glucocorticoid administration.

METHODS

We administered cigarette smoke solution (CSS) to eight-week-old male Sprague Dawley rats for four weeks, then examined laryngeal mucus secretion and inflammatory cytokine expression on days 1, 28 and 90 after smoking cessation. We also investigated the effects of the glucocorticoid triamcinolone acetonide when administered on day 1 after smoking cessation.

RESULTS

Exposure to CSS resulted in an increase in laryngeal mucus secretion that was further excacerbated following smoking cessation. This change coincided with an increase in the expression of mRNA for the inflammatory cytokines tumor necrosis factor and interleukin-6, as well as mRNA for MUC5AC, which is involved in mucin production. Triamcinolone suppressed CSS-induced laryngeal mucus hypersecretion and pro-inflammatory cytokine production.

CONCLUSION

Cigarette smoke-associated inflammation may contribute to the exacerbated laryngeal mucus hypersecretion that occurs following smoking cessation. The inflammatory response represents a promising target for the treatment of cigarette smoke-associated mucus hypersecretion.

The glucocorticoid budesonide has protective and deleterious effects in experimental colitis in mice

Glucocorticoids are widely used for the management of inflammatory bowel disease, albeit with known limitations for long-term use and relevant adverse effects. In turn, they have harmful effects in experimental colitis. We aimed to explore the mechanism and possible implications of this phenomenon. Regular and microbiota depleted C57BL/6 mice were exposed to dextran sulfate sodium (DSS) to induce colitis and treated with budesonide. Colonic inflammation and animal status were compared. In vitro epithelial models of wound healing were used to confirm the effects of glucocorticoids. Budesonide was also tested in lymphocyte transfer colitis. Budesonide (1-60μg/day) exerted substantial colonic antiinflammatory effects in DSS colitis. At the same time, it aggravated body weight loss, increased rectal bleeding, and induced general deterioration of animal status, bacterial translocation and endotoxemia. As a result, there was an associated increase in parameters of sepsis, such as plasma NOx, IL-1β, IL-6, lung myeloperoxidase and iNOS, as well as significant hypothermia. Budesonide also enhanced DSS induced colonic damage in microbiota depleted mice. These effects were correlated with antiproliferative effects at the epithelial level, which are expected to impair wound healing. In contrast, budesonide had significant but greatly diminished deleterious effects in noncolitic mice or in mice with lymphocyte transfer colitis. We conclude that budesonide weakens mucosal barrier function by interfering with epithelial dynamics and dampening the immune response in the context of significant mucosal injury, causing sepsis. This may be a contributing factor, at least in part, limiting clinical usefulness of corticoids in inflammatory bowel disease.

Endogenous circadian regulation of pro-inflammatory cytokines and chemokines in the presence of bacterial lipopolysaccharide in humans

Various aspects of immune response exhibit 24-h variations suggesting that infection susceptibility and treatment efficacy may vary by time of day. Whether these 24-h variations are endogenous or evoked by changes in environmental or behavioral conditions is not known. We assessed the endogenous circadian control and environmental and behavioral influences on ex-vivo lipopolysaccharide stimulation of whole blood in thirteen healthy participants under 48h of baseline conditions with standard sleep-wake schedules and 40-50h of constant environmental and behavioral (constant routine; CR) conditions. Significant 24-h rhythms were observed under baseline conditions in Monocyte Chemotactic Protein, Granulocyte-Macrophage Colony-Stimulating Factor and Interleukin 8 but not Tumor Necrosis Factor alpha whereas significant 24-h rhythms were observed in all four immune factors under CR conditions. The rhythm amplitudes, expressed as a percentage of mean, were comparable between immune factors and across conditions. In contrast, the acrophase time (time of the fitted peak) was different between immune factors, and included daytime and nighttime peaks and changes across behavioral conditions. These results suggest that the endogenous circadian system underpins the temporal organization of immune responses in humans with additional effects of external environmental and behavioral cycles. These findings have implications for understanding the adverse effects of recurrent circadian disruption and sleep curtailment on immune function.

TNF superfamily protein-protein interactions: feasibility of small- molecule modulation

The tumor necrosis factor (TNF) superfamily (TNFSF) contains about thirty structurally related receptors (TNFSFRs) and about twenty protein ligands that bind to one or more of these receptors. Almost all of these cell surface protein-protein interactions (PPIs) represent high-value therapeutic targets for inflammatory or immune modulation in autoimmune diseases, transplant recipients, or cancers, and there are several biologics including antibodies and fusion proteins targeting them that are in various phases of clinical development. Small-molecule inhibitors or activators could represent possible alternatives if the difficulties related to the targeting of protein-protein interactions by small molecules can be addressed. Compounds proving the feasibility of such approaches have been identified through different drug discovery approaches for a number of these TNFSFR-TNFSF type PPIs including CD40-CD40L, BAFFR-BAFF, TRAIL-DR5, and OX40-OX40L. Corresponding structural, signaling, and medicinal chemistry aspects are briefly reviewed here. While none of these small-molecule modulators identified so far seems promising enough to be pursued for clinical development, they provide proof-of-principle evidence that these interactions are susceptible to small-molecule modulation and can serve as starting points toward the identification of more potent and selective candidates.

N-acetyl cysteine improves the effects of corticosteroids in a mouse model of chlorine-induced acute lung injury

Chlorine (Cl2) causes tissue damage and a neutrophilic inflammatory response in the airways manifested by pronounced airway hyperreactivity (AHR). The importance of early anti-inflammatory treatment has previously been addressed. In the previous study, both high-dose and low-dose of dexamethasone (DEX) decreased the risk of developing delayed effects, such as persistent lung injuries, while only high-dose treatment could significantly counteract acute-phase effects. One aim of this study was to evaluate whether a low-dose of DEX in combination with the antioxidant N-acetyl cysteine (NAC) and if different treatments (Triptolide, Reparixin and Rolipram) administered 1h after Cl2-exposure could improve protection against acute lung injury in Cl2-exposed mice. BALB/c mice were exposed to 300 ppm Cl2 during 15 min. Assessment of AHR and inflammatory cells in bronchoalveolar lavage was analyzed 24h post exposure. Neither of DEX nor NAC reduced the AHR and displayed only minor effects on inflammatory cell influx when given as separate treatments. When given in combination, a protective effect on AHR and a significant reduction in inflammatory cells (neutrophils) was observed. Neither of triptolide, Reparixin nor Rolipram had an effect on AHR but Triptolide had major effect on the inflammatory cell influx. Treatments did not reduce the concentration of either fibrinogen or plasminogen activator inhibitor-1 in serum, thereby supporting the theory that the inflammatory response is not solely limited to the lung. These results provide a foundation for future studies aimed at identifying new concepts for treatment of chemical-induced lung injury. Studies addressing combination of anti-inflammatory and antioxidant treatment are highly motivated.