Thalidomide inhibits alternative activation of macrophages in vivo and in vitro: a potential mechanism of anti-asthmatic effect of thalidomide

Thalidomide Attenuates Mast Cell Activation by Upregulating SHP-1 Signaling and Interfering with the Action of CRBN

Allergy is a chronic inflammatory disease, and its incidence has increased worldwide in recent years. Thalidomide, which was initially used as an anti-emetic drug but was withdrawn due to its teratogenic effects, is now used to treat blood cancers. Although the anti-inflammatory and immunomodulatory properties of thalidomide have been reported, little is known about its influence on the mast cell-mediated allergic reaction. In the present study, we aimed to evaluate the anti-allergic activity of thalidomide and the underlying mechanism using mouse bone marrow-derived mast cells (BMMCs) and passive cutaneous anaphylaxis (PCA) mouse models. Thalidomide markedly decreased the degranulation and release of lipid mediators and cytokines in IgE/Ag-stimulated BMMCs, with concurrent inhibition of FcεRI-mediated positive signaling pathways including Syk and activation of negative signaling pathways including AMP-activated protein kinase (AMPK) and SH2 tyrosine phosphatase-1 (SHP-1). The knockdown of AMPK or SHP-1 with specific siRNA diminished the inhibitory effects of thalidomide on BMMC activation. By contrast, the knockdown of cereblon (CRBN), which is the primary target protein of thalidomide, augmented the effects of thalidomide. Thalidomide reduced the interactions of CRBN with Syk and AMPK promoted by FcεRI crosslinking, thereby relieving the suppression of AMPK signaling and suppressing Syk signaling. Furthermore, oral thalidomide treatment suppressed the PCA reaction in mice. In conclusion, thalidomide suppresses FcεRI-mediated mast cell activation by activating the AMPK and SHP-1 pathways and antagonizing the action of CRBN, indicating that it is a potential anti-allergic agent.

Intravenous Mesenchymal Stem Cell Administration Modulates Monocytes/Macrophages and Ameliorates Asthmatic Airway Inflammation in a Murine Asthma Model

Although asthma is a common chronic airway disease that responds well to anti-inflammatory agents, some patients with asthma are unresponsive to conventional treatment. Mesenchymal stem cells (MSCs) have therapeutic potential for the treatment of inflammatory diseases owing to their immunomodulatory properties. However, the target cells of MSCs are not yet clearly known. This study aimed to determine the effect of human umbilical cord-derived MSCs (hUC-MSCs) on asthmatic lungs by modulating innate immune cells and effector T cells using a murine asthmatic model. Intravenously administered hUC-MSCs reduced airway resistance, mucus production, and inflammation in the murine asthma model. hUC-MSCs attenuated not only T helper (Th) 2 cells and Th17 cells but also augmented regulatory T cells (Tregs). As for innate lymphoid cells (ILC), hUC-MSCs effectively suppressed ILC2s by downregulating master regulators of ILC2s, such as Gata3 and Tcf7. Finally, regarding lung macrophages, hUC-MSCs reduced the total number of macrophages, particularly the proportion of the enhanced monocyte-derived macrophage population. In a closer examination of monocyte-derived macrophages, hUC-MSCs reduced the M2a and M2c populations. In conclusion, hUC-MSCs can be considered as a potential anti- asthmatic treatment given their therapeutic effect on the asthmatic airway inflammation in a murine asthma model by modulating innate immune cells, such as ILC2s, M2a, and M2c macrophages, as well as affecting Tregs and effector T cells.

Thalidomide Exerts Anti-Inflammatory Effects in Cutaneous Lupus by Inhibiting the IRF4/NF-ҡB and AMPK1/mTOR Pathways

Thalidomide is effective in patients with refractory cutaneous lupus erythematosus (CLE). However, the mechanism of action is not completely understood, and its use is limited by its potential, severe side-effects. Immune cell subset analysis in thalidomide’s CLE responder patients showed a reduction of circulating and tissue cytotoxic T-cells with an increase of iNKT cells and a shift towards a Th2 response. We conducted an RNA-sequencing study using CLE skin biopsies performing a Therapeutic Performance Mapping System (TMPS) analysis in order to generate a predictive model of its mechanism of action and to identify new potential therapeutic targets. Integrating RNA-seq data, public databases, and literature, TMPS analysis generated mathematical models which predicted that thalidomide acts via two CRBN-CRL4A- (CRL4CRBN) dependent pathways: IRF4/NF-ҡB and AMPK1/mTOR. Skin biopsies showed a significant reduction of IRF4 and mTOR in post-treatment samples by immunofluorescence. In vitro experiments confirmed the effect of thalidomide downregulating IRF4 in PBMCs and mTOR in keratinocytes, which converged in an NF-ҡB reduction that led to a resolution of the inflammatory lesion. These results emphasize the anti-inflammatory role of thalidomide in CLE treatment, providing novel molecular targets for the development of new therapies that could avoid thalidomide’s side effects while maintaining its efficacy.

Effect of Acinetobacter lwoffii on the modulation of macrophage activation and asthmatic inflammation

BACKGROUND

Although lung macrophages are directly exposed to external stimuli, their exact immunologic roles in asthma are still largely unknown. The aim of this study was to investigate the anti-asthmatic effect of Acinetobacter lwoffii in terms of lung macrophage modulation.

METHODS

Six-week-old female BALB/c mice were sensitized and challenged with ovalbumin (OVA) with or without intranasal administration of A. lwoffii during the sensitization period. Airway hyperresponsiveness and inflammation were evaluated. Using flow cytometry, macrophages were subclassified according to their activation status. In the in vitro study, a murine alveolar macrophage cell line (MH-S) treated with or without A. lwoffii before IL-13 stimulation were analysed by quantitative RT-PCR.

RESULTS

In a murine asthma model, the number of inflammatory cells, including macrophages and eosinophils, decreased in mice treated with A. lwoffii (A. lwoffii/OVA group) compared with untreated mice (OVA group). The enhanced expression of MHCII in macrophages in the OVA group was decreased by A. lwoffii treatment. M2 macrophage subtypes were significantly altered. A. lwoffii treatment decreased CD11b⁺ M2a and CD11b⁺ M2c macrophages, which showed strong positive correlations with Th2 cells, ILC2 and eosinophils. In contrast, CD11b⁺ M2b macrophages were significantly increased by A. lwoffii treatment and showed strong positive correlations with ILC1 and ILC3. In vitro, A. lwoffii down-regulated the expression of M2 markers related but up-regulated those related to M2b macrophages.

CONCLUSIONS AND CLINICAL RELEVANCE

Intranasal A. lwoffii exposure suppresses asthma development by suppressing the type 2 response via modulating lung macrophage activation, shifting M2a and M2c macrophages to M2b macrophages.

Tranglutaminase 2 contributes to the asthmatic inflammation by modulating activation of alveolar macrophages

BACKGROUND

Transglutaminase 2 (TG2), a multifunctional calcium-dependent acyltransferase, is upregulated in asthmatic airways and reported to play a role in the pathogenesis of allergic asthma. However, the underlying mechanism is not fully understood.

OBJECTIVE

To investigate the role of TG2 in alternative activation of alveolar macrophages by using murine asthma model.

METHODS

TG2 expression was assessed in induced sputum of 21 asthma patients and 19 healthy controls, and lung tissue of ovalbumin (OVA)-induced murine asthma model. To evaluate the role of TG2 in asthma, we developed an OVA asthma model in both TG2 null and wild-type mice. The expression of M2 macrophage markers was measured by fluorescence-activated cell sorting (FACS) after OVA sensitization and challenge. To evaluate the effect of TG2 inhibition in vitro, interleukin 4 (IL-4) or IL-13-stimulated expression of M2 macrophage markers was measured in CRL-2456 cells in the presence and absence of a TG2 inhibitor.

RESULTS

The expression of both TG2 and M2 markers was increased in the sputum of asthmatics compared with that of healthy controls. The expression of TG2 was increased in macrophages of OVA mice. Airway hyperresponsiveness, and the number of inflammatory cells, including eosinophils, was significantly reduced in TG2 null mice compared with wild-type mice. Enhanced expression of M2 markers in OVA mice was normalized by TG2 knockout. IL-4 or IL-13-stimulated expression of M2 markers in alveolar macrophages was also attenuated by TG2 inhibitor treatment in vitro.

CONCLUSION

Our results suggest that TG2-mediated modulation of alveolar macrophage polarization plays important roles in the pathogenesis of asthma.

Efficacy of Thalidomide in Discoid Lupus Erythematosus: Insights into the Molecular Mechanisms

BACKGROUND

Thalidomide has been used successfully in a variety of chronic refractory inflammatory dermatological conditions with underlying autoimmune or infectious pathogenesis. It was first used for refractory discoid lupus erythematosus (DLE) in 1983 and has steadily grown since then.

METHOD

In this review, we describe the therapeutic benefits of thalidomide for DLE treatment and its biological properties. We explain how new discoveries in DLE pathogenesis are relevant to understand thalidomide's mechanism of action and the need to find an alternative safe drug with similar therapeutic effects.

SUMMARY

Thalidomide's efficacy in DLE patients is significant, with 80-90% reaching clinical remission according to different studies. However, thalidomide's use is still limited by serious adverse effects such as teratogenicity, neurotoxicity, and thrombosis. In addition, there is a frequent rate of relapse and many patients require a long-term low dose of thalidomide as maintenance. The achievement of clinical response within weeks is key to avoid irreversible DLE fibrotic sequelae, making it critical to introduce thalidomide earlier in the DLE treatment algorithm. Recently, microarray and miRNA screenings demonstrated a significant CD4+ T enrichment and T-helper 1 response predom-inance with a dysregulation of regulatory T cell (Treg) expression in DLE lesions that induced high levels of proinflammatory, chemotaxis, and apoptotic proteins that induce the chronic inflammation response. Thalidomide's anti-inflammatory, antiangiogenic, and T-cell co-stimulatory effects may be beneficial for DLE since it promotes cytokine inhibition, inhibits macrophage activation, regulates Treg responses, inhibits angiogenesis, modulates T cells, and promotes NK cell-mediated cytotoxicity.

Bacterial Outer Membrane Vesicles Provide Broad-Spectrum Protection against Influenza Virus Infection via Recruitment and Activation of Macrophages

Influenza A virus (IAV) poses a constant worldwide threat to human health. Although conventional vaccines are available, their protective efficacy is type or strain specific, and their production is time-consuming. For the control of an influenza pandemic in particular, agents that are immediately effective against a wide range of virus variants should be developed. Although pretreatment of various Toll-like receptor (TLR) ligands have already been reported to be effective in the defense against subsequent IAV infection, the efficacy was limited to specific subtypes, and safety concerns were also raised. In this study, we investigated the protective effect of an attenuated bacterial outer membrane vesicle -harboring modified lipid A moiety of lipopolysaccharide (fmOMV) against IAV infection and the underlying mechanisms. Administration of fmOMV conferred significant protection against a lethal dose of pandemic H1N1, PR8, H5N2, and highly pathogenic H5N1 viruses; this broad antiviral activity was dependent on macrophages but independent of neutrophils. fmOMV induced recruitment and activation of macrophages and elicited type I IFNs. Intriguingly, fmOMV showed a more significant protective effect than other TLR ligands tested in previous reports, without exhibiting any adverse effect. These results show the potential of fmOMV as a prophylactic agent for the defense against influenza virus infection.

Adjuvant Thalidomide and Metronomic Chemotherapy for the Treatment of Canine Malignant Mammary Gland Neoplasms

BACKGROUND/AIM

The aim of the present study was to evaluate a multimodal approach for the treatment of canine malignant mammary gland neoplasms, including surgery, chemotherapy, thalidomide, and metronomic chemotherapy (MC).

MATERIALS AND METHODS

Fifty-eight female dogs were submitted to four different treatments: surgery; surgery with chemotherapy; surgery with chemotherapy and thalidomide; and surgery with chemotherapy and metronomic chemotherapy and overall survival was evaluated.

RESULTS

No statistical difference was found in the proliferative index and microvessel density of primary neoplasms and distant metastases following thalidomide treatment. Diffuse intense inflammatory infiltrate was predominant in primary tumors and diffuse moderate inflammatory infiltrate in metastatic lesions. No statistically significant difference was observed in median survival time (MST) between treatment groups when including all clinical stages (p=0.3177). However, animals diagnosed with distant metastasis treated with surgery and chemotherapy associated with thalidomide or MC presented longer MST when compared to animals treated only with surgery or surgery and chemotherapy (p<0.0001).

CONCLUSION

The proposed multimodal therapy protocols including antiangiogenic and immunomodulatory therapies demonstrated a clinical benefit for patients in advanced clinical stages.

Suppressive Effect of 4-Hydroxy-2-(4-Hydroxyphenethyl) Isoindoline-1,3-Dione on Ovalbumin-Induced Allergic Asthma

4-Hydroxy-2-(4-hydroxyphenethyl)isoindoline-1,3-dione (PD1) is a synthetic phthalimide derivative of a marine compound. PD1 has peroxisome proliferator-activated receptor (PPAR) γ agonistic and anti-inflammatory effects. This study aimed to investigate the effect of PD1 on allergic asthma using rat basophilic leukemia (RBL)-2H3 mast cells and an ovalbumin (OVA)-induced asthma mouse model. In vitro, PD1 suppressed β-hexosaminidase activity in RBL-2H3 cells. In the OVA-induced allergic asthma mouse model, increased inflammatory cells and elevated Th2 and Th1 cytokine levels were observed in bronchoalveolar lavage fluid (BALF) and lung tissue. PD1 administration decreased the numbers of inflammatory cells, especially eosinophils, and reduced the mRNA and protein levels of the Th2 cytokines including interleukin (IL)-4 and IL-13, in BALF and lung tissue. The severity of inflammation and mucin secretion in the lungs of PD1-treated mice was also less. These findings indicate that PD1 could be a potential compound for anti-allergic therapy.

Down-regulation of common NFκB-iNOS pathway by chronic Thalidomide treatment improves Hepatopulmonary Syndrome and Muscle Wasting in rats with Biliary Cirrhosis

Thalidomide can modulate the TNFα-NFκB and iNOS pathway, which involve in the pathogenesis of hepatopulmonary syndrome (HPS) and muscle wasting in cirrhosis. In bile duct ligated-cirrhotic rats, the increased circulating CD16⁺ (inflammatory) monocytes and its intracellular TNFα, NFκB, monocyte chemotactic protein (MCP-1) and iNOS levels were associated with increased circulating MCP-1/soluable intercellular cell adehesion molecule-1 (sICAM-1), pulmonary TNFα/NOx, up-regulated M1 polarization, exacerbated angiogenesis and hypoxemia (increased AaPO₂) in bronchoalveolar lavage (BAL) fluid and pulmonary homogenates. Meanwhile, a significant correlation was noted between circulating CD16⁺ monocyte/M1 (%) macrophages in BAL; M1 (%) macrophages in BAL/pulmonary iNOS mRNA expression; pulmonary iNOS mRNA expression/relative pulmonary MVD; pulmonary NOx level/AaPO₂; circulating CD16⁺ monocyte/M1 (%) macrophages in muscle homogenates; 3-nitrotyrosine (representative of peroxynitrite) concentration/M1 (%) macrophages in muscle homogenates. The in vitro data demonstrated an iNOS-dependent inhibition of thalidomide on the TNFα-stimulated angiogenesis and myogenesis in human pulmonary artery endothelial cells (HPAECs) and C2C12 myoblasts. Significantly, the co-culture of CD16⁺ monocyte from different rats with HPAECs, or co-culture of supernatant of above mixed cultures with HPAECs or C2C12 myoblasts stimulated angiogenesis, migration and myogenesis. Our findings demonstrate that TNFα inhibitor thalidomide markedly diminishes the severity of experimental HPS and muscle wasting by down-regulation of common peripheral and local NFκB-iNOS pathway.

Importance of the interaction between immune cells and tumor vasculature mediated by thalidomide in cancer treatment (Review)

Over the past 60 years, thalidomide has metamorphosized from a drug prescribed to treat morning sickness in pregnant women, which was subsequently found to induce birth defects, into a highly effective therapy for treating leprosy and multiple myeloma. Several mechanisms have been proposed to explain the anticancer effects of thalidomide, including antiangiogenic and immunomodulatory activities. At present, evidence suggests that thalidomide may induce vessel maturation. Vascular normalization may be an effective strategy to enhance cancer immunotherapy. Numerous studies have shown that the tumor infiltrating immune cell subsets are important in regulating the process of tumor angiogenesis. The mechanisms associated with antiangiogenesis and the potent immunomodulatory effects of thalidomide obtained the most support. The studies of the antiangiogenic activity of thalidomide were guided in a novel direction by a hypothesis regarding the vascular normalization of tumors. Hence, thalidomide is effective in cancer treatment due to the interaction between immune cells and tumor vasculature. This mechanism provides new avenues to explore for the treatment of cancer.