Hydrogen peroxide increases interleukin-12 p40/p70 molecular ratio and induces Th2-predominant responses in mice

Combination therapy with hydrogen peroxide and irradiation promotes an abscopal effect in mouse models

Hydrogen peroxide (H2 O2 ) induces oxidative stress and cytotoxicity, and can be used for treating cancers in combination with radiotherapy. A product comprising H2 O2 and sodium hyaluronate has been developed as a radiosensitizer. However, the effects of H2 O2 on antitumor immunity remain unclear. To investigate the effects of H2 O2 , especially the abscopal effect when combined with radiotherapy (RT), we implanted murine tumor cells simultaneously in two locations in mouse models: the hind limb and back. H2 O2 mixed with sodium hyaluronate was injected intratumorally, followed by irradiation only at the hind limb lesion. No treatment was administered to the back lesion. The H2 O2 /RT combination significantly reduced tumor growth at the noninjected/nonirradiated site in the back lesion, whereas H2 O2 or RT individually did not reduce tumor growth. Flow cytometric analyses of the tumor-draining lymph nodes in the injected/irradiated areas showed that the number of dendritic cells increased significantly with maturation in the H2 O2 /RT combination group. In addition, analyses of tumor-infiltrating lymphocytes showed that the number of CD8+ (cluster of differentiation 8) T cells and the frequency of IFN-γ+ (interferon gamma) CD8+ T cells were higher in the noninjected/nonirradiated tumors in the H2 O2 /RT group compared to those in the other groups. PD-1 (programmed death receptor 1) blockade further increased the antitumor effect against noninjected/nonirradiated tumors in the H2 O2 /RT group. Intratumoral injection of H2 O2 combined with RT therefore induces an abscopal effect by activating antitumor immunity, which can be further enhanced by PD-1 blockade. These findings promote the development of H2 O2 /RT therapy combined with cancer immunotherapies, even for advanced cancers.

Inhibition of vascular adhesion protein-1 enhances the anti-tumor effects of immune checkpoint inhibitors

Modulation of the immunosuppressive tumor microenvironment (TME) is essential for enhancing the anti‐tumor effects of immune checkpoint inhibitors (ICIs). Adhesion molecules and enzymes such as vascular adhesion protein‐1 (VAP‐1), which are expressed in some cancers and tumor vascular endothelial cells, may be involved in the generation of an immunosuppressive TME. In this study, the role of VAP‐1 in TME was investigated in 2 murine colon cancer models and human cancer cells. Intraperitoneal administration of the VAP‐1‐specific inhibitor U‐V296 inhibited murine tumor growth by enhancing IFN‐γ‐producing tumor antigen‐specific CD8⁺ T cells. U‐V296 exhibited significant synergistic anti‐tumor effects with ICIs. In the TME of mice treated with U‐V296, the expression of genes associated with M2‐like macrophages, Th2 cells (Il4, Retnla, and Irf4), angiogenesis (Pecam1), and fibrosis (Acta2, Loxl2) were significantly decreased, and the Th1/Th2 balance was increased. H₂O₂, an enzymatic product of VAP‐1, which promoted the production of IL‐4 by mouse Th2 and inhibited IFN‐γ by mouse Th1 and human tumor‐infiltrating lymphocytes, was decreased in tumors and CD31⁺ tumor vascular endothelial cells in the TMEs of mice treated with VAP‐1 inhibitor. TCGA database analysis showed that VAP‐1 expression was a negative prognostic factor in human cancers, exhibiting a significant positive correlation with IL‐4, IL4R, and IL‐13 expression and a negative correlation with IFN‐γ expression. These results indicated that VAP‐1 is involved in the immunosuppressive TMEs through H₂O₂‐associated Th2/M2 conditions and may be an attractive target for the development of combination cancer immunotherapy with ICIs.

Keratinocytes-Derived Reactive Oxygen Species Play an Active Role to Induce Type 2 Inflammation of the Skin: A Pathogenic Role of Reactive Oxygen Species at the Early Phase of Atopic Dermatitis

Background

Atopic dermatitis (AD) is characterized by chronic, relapsing skin inflammation (eczema) with itchy sensation. Keratinocytes, which are located at the outermost part of our body, are supposed to play important roles at the early phase of type 2 inflammation including AD pathogenesis.

Objective

The purpose of this study was to evaluate whether keratinocytes-derived reactive oxygen species (ROS) could be produced by the allergens or non-allergens, and the keratinocytes-derived ROS could modulate a set of biomarkers for type 2 inflammation of the skin.

Methods

Normal human epidermal keratinocytes (NHEKs) were treated with an allergen of house dust mites (HDM) or a non-allergen of compound 48/80 (C48/80). Then, biomarkers for type 2 inflammation of the skin including those for neurogenic inflammation were checked by reverse transcriptase-polymerase chain reaction and western immunoblot experiments.

Results

HDM or C48/80 was found to upregulate expression levels of our tested biomarkers, including type 2 T helper-driving pathway (KLK5, PAR2, and NFκB), epithelial-cell-derived cytokines (thymic stromal lymphopoietin, interleukin [IL]-25, IL-33), and neurogenic inflammation (NGF, CGRP). The HDM- or C-48/80-induced expression levels of the biomarkers could be blocked by an antioxidant treatment with 5 mM N-acetyl-cysteine. In contrast, pro-oxidant treatment with 1 mM H₂O₂ could upregulate expression levels of the tested biomarkers in NHEKs.

Conclusion

Our results reveal that keratinocytes-derived ROS, irrespective to their origins from allergens or non-allergens, have a potential to induce type 2 inflammation of AD skin.

Oligonucleotide IMT504 Improves Glucose Metabolism and Controls Immune Cell Mediators in Female Diabetic NOD Mice

Type 1 diabetes occurs as a consequence of progressive autoimmune destruction of beta cells. A potential treatment for this disease should address the immune attack on beta cells and their preservation/regeneration. The objective of this study was to elucidate whether the immunomodulatory synthetic oligonucleotide IMT504 was able to ameliorate diabetes in NOD mice and to provide further understanding of its mechanism of action. We found that IMT504 restores glucose homeostasis in a diabetes mouse model similar to human type 1 diabetes, by regulating expression of immune modulatory factors and improving beta cell function. IMT504 treatment markedly improved fasting glycemia, insulinemia, and homeostatic model assessment of beta cell function (HOMA-Beta cell) index. Moreover, this treatment increased islet number and decreased apoptosis, insulitis, and CD45⁺ pancreas-infiltrating leukocytes. In a long-term treatment, we observed improvement of glucose metabolism up to 9 days after IMT504 cessation and increased survival after 15 days of the last IMT504 injection. We postulate that interleukin (IL)-12B (p40), possibly acting as a homodimer, and Galectin-3 (Gal-3) may function as mediators of this immunomodulatory action. Overall, these results validate the therapeutic activity of IMT504 as a promising drug for type 1 diabetes and suggest possible downstream mediators of its immunomodulatory effect.

Intratumoral Hydrogen Peroxide With Radiation Therapy in Locally Advanced Breast Cancer: Results From a Phase 1 Clinical Trial

PURPOSE

Hydrogen peroxide (H2O2) plays a vital role in normal cellular processes but at supraphysiological concentrations causes oxidative stress and cytotoxicity, a property that is potentially exploitable for the treatment of cancer in combination with radiation therapy (RT). We report the first phase 1 trial testing the safety and tolerability of intratumoral H2O2 + external beam RT as a novel combination in patients with breast cancer and exploratory plasma marker analyses investigating possible mechanisms of action.

METHODS AND MATERIALS

Twelve patients with breast tumors ≥3 cm (surgically or medically inoperable) received intratumoral H2O2 with either 36 Gy in 6 twice-weekly fractions (n = 6) or 49.5 Gy in 18 daily fractions (n = 6) to the whole breast ± locoregional lymph nodes in a single-center, nonrandomized study. H2O2 was mixed in 1% sodium hyaluronate gel (final H2O2 concentration 0.5%) before administration to slow drug release and minimize local discomfort. The mixture was injected intratumorally under ultrasound guidance twice weekly 1 hour before RT. The primary endpoint was patient-reported maximum intratumoral pain intensity before and 24 hours postinjection. Secondary endpoints included grade ≥3 skin toxicity and tumor response by ultrasound. Blood samples were collected before, during, and at the end of treatment for cell-death and immune marker analysis.

RESULTS

Compliance with H2O2 and RT was 100%. Five of 12 patients reported moderate pain after injection (grade 2 Common Terminology Criteria for Adverse Events v4.02) with median duration 60 minutes (interquartile range, 20-120 minutes). Skin toxicity was comparable to RT alone, with maintained partial/complete tumor response relative to baseline in 11 of 12 patients at last follow-up (median 12 months). Blood marker analysis highlighted significant associations of TRAIL, IL-1β, IL-4, and MIP-1α with tumor response.

CONCLUSIONS

Intratumoral H2O2 with RT is well tolerated with no additional toxicity compared with RT alone. If efficacy is confirmed in a randomized phase 2 trial, the approach has potential as a cost-effective radiation response enhancer in multiple cancer types in which locoregional control after RT alone remains poor.

Oxidative stress modulates the cytokine response of differentiated Th17 and Th1 cells

Reactive oxygen species (ROS) signaling is critical in T helper (Th) cell differentiation; however its role in differentiated Th cell functions is unclear. In this study, we investigated the role of oxidative stress on the effector functions of in vitro differentiated mouse Th17 and Th1 cells or CD4⁺ T cells from patients with Rheumatoid Arthritis using pro-oxidants plumbagin (PB) and hydrogen peroxide. We found that in mouse Th cells, non-toxic concentration of pro-oxidants inhibited reactivation induced expression of IL-17A in Th17 and IFN-γ in Th1 cells by reducing the expression of their respective TFs, RORγt and T-bet. Interestingly, in both the subsets, PB increased the expression of IL-4 by enhancing reactivation induced ERK1/2 phosphorylation. We further investigated the cytokine modulatory effect of PB on CD4⁺ T cells isolated from PBMCs of patients with Rheumatoid Arthritis, a well-known Th17 and or Th1 mediated disease. In human CD4⁺ T cells from Rheumatoid Arthritis patients, PB reduced the frequencies of IL-17A⁺ (Th17), IFN^-γ⁺ (Th1) and IL-17A⁺/IFN^-γ⁺ (Th17/1) cells and also inhibited the production of pro-inflammatory cytokines TNF-α and IL-6. N-Acetyl Cysteine (NAC) an antioxidant completely reversed PB mediated cytokine modulatory effects in both mouse and human cells indicating a direct role for ROS. Together our data suggest that oxidative microenvironment can alter cytokine response of terminally differentiated cells and thus altering intracellular ROS could be a potential way to target Th17 and Th1 cells in autoimmune disorders.

Immunomodulatory Effects of Ambroxol on Airway Hyperresponsiveness and Inflammation

Ambroxol is used in COPD and asthma to increase mucociliary clearance and regulate surfactant levels, perhaps through anti-oxidant and anti-inflammatory activities. To determine the role and effect of ambroxol in an experimental model of asthma, BALB/c mice were sensitized to ovalbumin (OVA) followed by 3 days of challenge. Airway hyperresponsiveness (AHR), lung cell composition and histology, and cytokine and protein carbonyl levels in bronchoalveolar lavage (BAL) fluid were determined. Ambroxol was administered either before the first OVA challenge or was begun after the last allergen challenge. Cytokine production levels from lung mononuclear cells (Lung MNCs) or alveolar macrophages (AM) were also determined. Administration of ambroxol prior to challenge suppressed AHR, airway eosinophilia, goblet cell metaplasia, and reduced inflammation in subepithelial regions. When given after challenge, AHR was suppressed but without effects on eosinophil numbers. Levels of IL-5 and IL-13 in BAL fluid were decreased when the drug was given prior to challenge; when given after challenge, increased levels of IL-10 and IL-12 were detected. Decreased levels of protein carbonyls were detected in BAL fluid following ambroxol treatment after challenge. In vitro, ambroxol increased levels of IL-10, IFN-γ, and IL-12 from Lung MNCs and AM, whereas IL-4, IL-5, and IL-13 production was not altered. Taken together, ambroxol was effective in preventing AHR and airway inflammation through upregulation of Th1 cytokines and protection from oxidative stress in the airways.

Association of IL12A Expression Quantitative Trait Loci (eQTL) With Primary Biliary Cirrhosis in a Chinese Han Population

Genome-wide association studies in European individuals have revealed that IL12A is strongly associated with primary biliary cirrhosis (PBC). However, this association was not detected in replicative studies conducted in Chinese Han and Japanese populations.To verify contributions of genetic variants of IL12A to the pathogenesis of PBC in Chinese populations, a replicative study of 22 single nucleotide polymorphisms (SNPs) around the IL12A gene locus was performed in a cohort of 586 PBC cases and 726 healthy controls. Three out of the 22 SNPs were significantly associated with PBC. The 2 SNPs with the most significant association signal were rs4679868 (P = 6.59E-05, odds ratio [OR] = 1.554 [1.253-1.927]) and rs6441286 (P = 8.00E-05, OR = 1.551 [1.250-1.924]). These 2 SNPs were strongly linked to each other (r = 0.981), and both were found to be significantly associated with PBC in European populations.An expression quantitative trait loci (eQTL) analysis was performed based on the observation that these 2 SNPs were located in proximity to 2 enhancers verified by luciferase reporter systems in the HEK293 cell line. The results of eQTL analysis, conducted using the publically accessible data, showed that the risk alleles of rs4679868 and rs6441286 were significantly associated with decreased expression of IL12A in lymphoblastoid cell lines derived from individuals of Chinese Han ancestry (P = 0.0031 for rs4679868 and P = 0.0073 for rs6441286). In addition, the risk alleles of the 2 SNPs were significantly associated with down-regulation of SCHIP1, a celiac disease susceptible gene, 91.5 kb upstream of IL12A.These results not only demonstrated that IL12A is associated with PBC in the Chinese Han population but also identified a potential mechanism for its involvement in the pathogenesis of PBC.

Toona sinensis Roem leaf extracts improve antioxidant activity in the liver of rats under oxidative stress

Toona sinensis Roem (TS) is an herbal plant widely cultivated in Asia. Recently, several antioxidant compounds in TS leaf (TSL) extracts were chemically identified including quercetin, gallic acid, and others. However, in vivo experiments regarding the antioxidative function of TSL are limited. In this study, Sprague Dawley (SD) rats with oxidative stress were successfully established by intraperitoneal injection of hydrogen peroxide (H(2)O(2)) (1mmol/kg BW) and fed with different TSL extracts for in vivo antioxidation evaluation. Among the TSLs tested in this study, TSL6 exhibited the best antioxidative effects which increased the enzyme activities of catalase, cupper/zinc superoxide dismutase (Cu/Zn SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and Glutathione S transferase (GST) activities in liver compared to those in TSL-2 and TSL-2P groups. In conclusion, we provide the strong in vivo evidences for the first time that TSL extracts ameliorate the antioxidant enzymes (AOEs) activity in liver and is beneficial for the hepatic detoxification.

Cationic amino acid transporter 2 enhances innate immunity during Helicobacter pylori infection

Once acquired, Helicobacter pylori infection is lifelong due to an inadequate innate and adaptive immune response. Our previous studies indicate that interactions among the various pathways of arginine metabolism in the host are critical determinants of outcomes following infection. Cationic amino acid transporter 2 (CAT2) is essential for transport of L-arginine (L-Arg) into monocytic immune cells during H. pylori infection. Once within the cell, this amino acid is utilized by opposing pathways that lead to elaboration of either bactericidal nitric oxide (NO) produced from inducible NO synthase (iNOS), or hydrogen peroxide, which causes macrophage apoptosis, via arginase and the polyamine pathway. Because of its central role in controlling L-Arg availability in macrophages, we investigated the importance of CAT2 in vivo during H. pylori infection. CAT2(-/-) mice infected for 4 months exhibited decreased gastritis and increased levels of colonization compared to wild type mice. We observed suppression of gastric macrophage levels, macrophage expression of iNOS, dendritic cell activation, and expression of granulocyte-colony stimulating factor in CAT2(-/-) mice suggesting that CAT2 is involved in enhancing the innate immune response. In addition, cytokine expression in CAT2(-/-) mice was altered from an antimicrobial Th1 response to a Th2 response, indicating that the transporter has downstream effects on adaptive immunity as well. These findings demonstrate that CAT2 is an important regulator of the immune response during H. pylori infection.

[Preferential induction of apoptosis in regulatory T cells by tributyltin: possible involvement in the exacerbation of allergic diseases]

OBJECTIVES

Tributyltin (TBT) has been recognized as a particularly important pollutant. Human exposure to TBT persists via consumption of TBT-containing meat and fish products. Although it is well known that high-dose TBT exerts immunotoxic effects such as thymic atrophy, the effect of low-dose TBT exposure on immune responses remains elusive. Our previous studies demonstrated that TBT at environmentally relevant doses promoted T helper (Th)2 polarization via enhancement of Th2 differentiation and preferential induction of apoptosis in Th1, which is associated with the exacerbation of Th2-driven allergic airway inflammation. In the present study, we explored the possibility that TBT might preferentially induce apoptosis in Foxp3(+) regulatory T cells (Treg), which play an indisputable role in the negative regulation of immune responses.

METHODS

We established several independent Treg and Th2 clones and their susceptibilities to TBT-induced apoptosis were examined. To examine whether the susceptibility to TBT-induced apoptosis may be due to the level of glutathione (GSH), we measured the basal GSH levels in Treg and Th2 clones. Intracellular GSH level was measured using high-performance liquid chromatography (HPLC) with a gold electrode.

RESULTS

We show that TBT preferentially induces apoptosis in Treg clones rather than in Th2 clones. The basal levels of GSH in Treg clones were significantly lower than those in Th2 clones.

CONCLUSIONS

The increased susceptibility of Treg clones to TBT-induced apoptosis appeared to result from lower GSH levels in Treg clones, which may detoxify the reactive oxygen species (ROS) induced by TBT treatment. Our results suggest that the preferential induction of apoptosis in Treg over Th2 contributes to the exacerbation of Th2-driven allergic diseases by TBT.

Oxidative stress and the pathogenesis of scleroderma: the Murrell's hypothesis revisited

Systemic sclerosis (SSc, scleroderma) is a devastating, immune-mediated, multisystem disorder characterized by microvasculature damage, circulating autoantibodies, and fibroblast activation, leading to massive fibrosis of skin, vessels, muscles, and visceral organs. Scleroderma causes disability and death as the result of end-stage organ failure. At present, no specific diagnostic nor therapeutic tools are available to handle the disease. In spite of significant effort, the etiology and pathogenesis of SSc remain obscure and, consequently, the disease outcome is unpredictable. Several years ago, Murrell suggested a unifying hypothesis linking the pathogenesis of scleroderma to the generation of a large excess of reactive oxygen species. This hypothesis has been substantiated by several reports indicating the presence of an abnormal redox state in patients with scleroderma. This review will summarize the available evidence supporting the link between free radicals and the main pathological features of scleroderma.

Differences in the inducible gene expression and protein production of IL-12p40, IL-12p70 and IL-23: involvement of p38 and JNK kinase pathways

The proper balance between IL-12p40-related cytokines controls the appearance of normal and pathological Th1 immune responses. In this study, we examined the inducible IL-12p40, IL-12p35 and IL-23p19 mRNA expression and protein production in human peripheral blood mononuclear cells (PBMC) and purified monocytes, isolated from healthy donors. We investigated how JNK and p38 MAPKs inhibitors influenced IL-12p40, IL-12p70 and IL-23 production. The cytokines' quantity determination was performed by ELISA. qRT-PCR was performed for mRNA transcripts detection. All stimuli tested induced higher level of IL-12p40 and IL-12p19 mRNAs. LPS was the strongest inducer of IL-12p40 mRNA, whereas C3bgp stimulated the highest expression of IL-23p19 mRNA in human monocytes. IL-12p40 and IL-23 protein production observed was increased in the highest level after C3bgp stimulation. The inhibition of both JNK and p38 augmented IL-12p40 production. The inhibition of p38 MAPK downregulated IL-23 production and upregulated IL-12p40 production in stimulated monocytes and PBMC. These results provide evidence that in human monocytes and PBMC p38 MAP kinase activation has an opposite effect on the IL-12p40 and IL-23 expression.

Activation of NF-kappaB in lymphocytes and increase in serum immunoglobulin in hyperthyroidism: possible role of oxidative stress

This study evaluated oxidative stress, serum IgM and IgG, and nuclear factor (NF)-kappaB signaling in lymphocytes of hyperthyroidism patients. GSH content in lymphocytes was significantly lower and serum malondialdehyde, IgM and IgG levels were significantly higher in hyperthyroidism as compared to controls. In lymphocytes, the NF-kappaB signaling pathway was studied by western blot analysis of p65 and p-IkappaBalpha. Density of p-IkappaBalpha and p65 (in nuclear fraction) was significantly higher in hyperthyroidism as compared to controls. The density of p-IkappaBalpha and p65 had significant positive correlation with serum malondialdehyde level and negative correlation with lymphocyte GSH level in hyperthyroid cases. The serum IgG and IgM levels were correlated significantly with density of p-IkappaBalpha and p65. As immunoglobulin production is regulated by the NF-kappaB pathway, we conclude that the oxidative stress-induced activation of the NF-kappaB pathway might play a role in the rise of serum immunoglobulin level in hyperthyroidism.

Oxidative microenvironment exerts an opposite regulatory effect on cytokine production by Th1 and Th2 cells

Oxidative stress occurs in allergic disorders and immunologic inflammatory responses and reactive oxygen metabolites have an additional role of cell-signaling mediators, influencing many biological processes. Using in vitro derived Th1 and Th2 clones or T cells derived from autoimmune thyroiditis we study the ability of Th1 or Th2 cells to expand and produce cytokine in an oxidative environment. We found that low-doses of H2O2 reduce the INF-gamma production of activated Th1 clones and potentiate the IL-4 secretion of activated Th2 clones. These effects were not due to altered cell proliferation and are not transient, since the modified secretion profile was still retained after 1 week from H2O2 stimulation by both Th1 and Th2 cells. H2O2 influence the profile of cytokine secretion in both Th1 and Th2. These effects are long lasting and are the result of an action of H2O2 on T cell. In conclusion we demonstrate that oxidative stress plays an important role in the pathogenesis of allergic respiratory diseases and can up-regulate Th2-driven inflammation, thus contributing to increase disease severity, bronchial hyper-responsiveness and airway remodeling.

Leishmania major induces distinct neutrophil phenotypes in mice that are resistant or susceptible to infection

Polymorphonuclear neutrophils (PMN) are key components of the inflammatory response contributing to the development of pathogen-specific immune responses. Following infection with Leishmania major, neutrophils are recruited within hours to the site of parasite inoculation. C57BL/6 mice are resistant to infection, and BALB/c mice are susceptible to infection, developing unhealing, inflammatory lesions. In this report, we investigated the expression of cell surface integrins, TLRs, and the secretion of immunomodulatory cytokines by PMN of both strains of mice, in response to infection with L. major. The parasite was shown to induce CD49d expression in BALB/c-inflammatory PMN, and expression of CD49d remained at basal levels in C57BL/6 PMN. Equally high levels of CD11b were expressed on PMN from both strains. In response to L. major infection, the levels of TLR2, TLR7, and TLR9 mRNA were significantly higher in C57BL/6 than in BALB/c PMN. C57BL/6 PMN secreted biologically active IL-12p70 and IL-10. In contrast, L. major-infected BALB/c PMN transcribed and secreted high levels of IL-12p40 but did not secrete biologically active IL-12p70. Furthermore, IL-12p40 was shown not to associate with IL-23 p19 but formed IL-12p40 homodimers with inhibitory activity. No IL-10 was secreted by BALB/c PMN. Thus, following infection with L. major, in C57BL/6 mice, PMN could constitute one of the earliest sources of IL-12, and in BALB/c mice, secretion of IL-12p40 could contribute to impaired, early IL-12 signaling. These distinct PMN phenotypes may thus influence the development of L. major-specific immune response.