Effects of suplatast tosilate on cytokine profile of bronchoalveolar cells in allergic inflammation of the lung

Pharmaceutical targeting Th2-mediated immunity enhances immunotherapy response in breast cancer

BACKGROUND

Breast cancer is a complex disease with a highly immunosuppressive tumor microenvironment, and has limited clinical response to immune checkpoint blockade (ICB) therapy. T-helper 2 (Th2) cells, an important component of the tumor microenvironment (TME), play an essential role in regulation of tumor immunity. However, the deep relationship between Th2-mediated immunity and immune evasion in breast cancer remains enigmatic.

METHODS

Here, we first used bioinformatics analysis to explore the correlation between Th2 infiltration and immune landscape in breast cancer. Suplatast tosilate (IPD-1151 T, IPD), an inhibitor of Th2 function, was then employed to investigate the biological effects of Th2 blockade on tumor growth and immune microenvironment in immunocompetent murine breast cancer models. The tumor microenvironment was analyzed by flow cytometry, mass cytometry, and immunofluorescence staining. Furthermore, we examined the efficacy of IPD combination with ICB treatment by evaluating TME, tumor growth and mice survival.

RESULTS

Our bioinformatics analysis suggested that higher infiltration of Th2 cells indicates a tumor immunosuppressive microenvironment in breast cancer. In three murine breast cancer models (EO771, 4T1 and EMT6), IPD significantly inhibited the IL-4 secretion by Th2 cells, promoted Th2 to Th1 switching, remodeled the immune landscape and inhibited tumor growth. Remarkably, CD8⁺ T cell infiltration and the cytotoxic activity of cytotoxic T lymphocyte (CTL) in tumor tissues were evidently enhanced after IPD treatment. Furthermore, increased effector CD4⁺ T cells and decreased myeloid-derived suppressor cells and M2-like macrophages were also demonstrated in IPD-treated tumors. Importantly, we found IPD reinforced the therapeutic response of ICB without increasing potential adverse effects.

CONCLUSIONS

Our findings demonstrate that pharmaceutical inhibition of Th2 cell function improves ICB response via remodeling immune landscape of TME, which illustrates a promising combinatorial immunotherapy.

Imaging of Hydroxyl-Radical Generation Using Dynamic Nuclear Polarization-Magnetic Resonance Imaging and a Spin-Trapping Agent

Reactive oxygen species (ROS) play an important role in cell metabolism, but they can cause oxidative damage to biomolecules. Among ROS, the hydroxyl radical (·OH) is one of the most reactive molecules in biological systems because of its high reaction rate constant. Therefore, imaging of ·OH could be useful for evaluation of the redox mechanism and diagnosis of oxidative diseases. In vivo dynamic nuclear polarization-magnetic resonance imaging (DNP-MRI) is a noninvasive imaging method to obtain spatiotemporal information about free radicals with MRI anatomical resolution. In this study, we investigated the visualization of hydroxyl radicals generated from the Fenton reaction by combining DNP-MRI with a spin-trapping agent (DMPO: 5,5-dimethyl-1-pyrroline N-oxide) for ·OH. Additionally, we demonstrated the radical-scavenging effect using four thiol-related reagents by DNP-MRI. We demonstrated that DNP enhancement could be induced by the DMPO-OH radical using the DNP-MRI/spin-trapping method and visualized ·OH generation for the first time. Maximum DNP enhancement was observed at an electron paramagnetic resonance irradiation frequency of 474.5 MHz. Furthermore, the radical-scavenging effect was simultaneously evaluated by the decrease in the DNP image value of DMPO-OH. An advantage of our methods is that they simultaneously investigate compound activity and the radical-scavenging effect.

Interleukin 4: Its Role in Hypertension, Atherosclerosis, Valvular, and Nonvalvular Cardiovascular Diseases

Hypertension is one of the major physiological risk factors for cardiovascular diseases, and it affects more than 1 billion adults worldwide, killing 9 million people every year according to World Health Organization. Also, hypertension is associated with increased risk of kidney disease and stroke. Studying the risk factors that contribute to the pathogenesis of hypertension is key to preventing and controlling hypertension. Numerous laboratories around to globe are very active pursuing research studies to delineate the factors, such as the role of immune system, which could contribute to hypertension. There are studies that were conducted on immune-deficient mice for which experimentally induced hypertension has been ameliorated. Thus, there are possibilities that immune reactivity could be associated with the development of certain type of hypertension. Furthermore, interleukin 4 has been associated with the development of pulmonary hypertension, which could lead to right ventricular remodeling. Also, the immune system is involved in valvular and nonvalvular cardiac remodeling. It has been demonstrated that there is a causative relationship between different interleukins and cardiac fibrosis.

Suplatast tosilate protects the lung against hyperoxic lung injury by scavenging hydroxyl radicals

Prolonged exposure to hyperoxia produces extraordinary amounts of reactive oxygen species (ROS) in the lung and causes hyperoxic lung injury. Although supraphysiological oxygen is routinely administered for the management of respiratory failure, there is no effective strategy to prevent hyperoxic lung injury. In our previous study, we showed that suplatast tosilate, an asthma drug that inhibits T helper 2 (Th2) cytokines, ameliorated bleomycin-induced lung injury and fibrosis through Th2-independent mechanisms. Because bleomycin also generates ROS, we hypothesized that suplatast tosilate might have antioxidant activity and protect the lung against hyperoxic lung injury. To test this hypothesis, mice exposed to hyperoxia were given suplatast tosilate through drinking water. Treatment with suplatast tosilate significantly prolonged mouse survival, reduced the increases in the numbers of inflammatory cells, levels of the pro-inflammatory cytokines/chemokines IL-6 and MCP-1, and protein in bronchoalveolar lavage fluid, and ameliorated lung injury in histological assessment. Suplatast tosilate treatment also significantly inhibited hyperoxia-induced elevations in the levels of 8-hydroxydeoxyguanosine, a marker of oxidative DNA damage, in bronchoalveolar lavage fluid and 8-isoprostane, a marker of lipid peroxidation, in lung tissue. This finding suggests that suplatast tosilate exerts an antioxidant activity in vivo. In addition, we investigated whether suplatast tosilate has a scavenging effect on hydroxyl radical, the most reactive and harmful ROS, using electron paramagnetic resonance spin-trapping. Suplatast tosilate was shown to scavenge hydroxyl radicals in a dose-dependent manner, and its reaction rate constant with hydroxyl radical was calculated as 2.6×10¹¹M^-1S^-1, which is faster than that of several well-established antioxidants, such as ascorbate, glutathione, and cysteine. These results suggest that suplatast tosilate protects the lung against hyperoxic lung injury by decreasing the degree of oxidative stress induced by ROS, particularly by scavenging hydroxyl radicals. Suplatast tosilate might become a potential therapeutic for hyperoxic lung injury.

Suplatast tosilate ameliorates airway hyperreactivity and inflammation through inhibition of the GATA‑3/IL‑5 signaling pathway in asthmatic rats

Airway hyperreactivity and inflammation are important factors in the aggravation of lung function. Suplatast tosilate (IPD) is a novel and unique anti‑asthma clinical compound. However, the mechanisms of IPD action in the inhibition of asthma remain to be elucidated. The present study aimed to investigate the role of the GATA binding protein 3 (GATA‑3)/interleukin (IL)‑5 signaling pathway in IPD‑induced inhibition of asthma. Sprague‑Dawley rats were sensitized by intraperitoneal injection with ovalbumin (OVA) to establish an animal model of asthma. IPD was administered continuously (C‑IPD) or at a later stage (L‑IPD). Budesonide (BUD) was used as a positive control. Airway resistance and the expression of genes at the mRNA and protein levels were measured. Morphological changes in lung tissue and the percentage of eosinophils (EOS) in peripheral blood were observed and correlation analysis was performed. The results revealed that sensitization by OVA significantly increased airway resistance and the percentage of EOS in peripheral blood and induced significant inflammatory changes in lung tissue, as demonstrated by thick epithelium, goblet cell hyperplasia and submucosal cell infiltration. In addition, sensitization by OVA was found to markedly upregulate IL‑5 mRNA and protein expression. Airway resistance was found to positively correlate with the expression of IL‑5 in the rat lung tissues. Sensitization by OVA was also observed to markedly enhance GATA‑3 protein expression and GATA‑3 levels were found to positively correlate with airway resistance and IL‑5 levels. Similar to the effect of BUD, treatment with C‑IPD or L‑IPD was found to significantly attenuate OVA‑induced increases in airway resistance and the percentage of EOS in peripheral blood. Notably, treatment with C‑IPD or L‑IPD markedly reduced the OVA-induced expression of IL‑5 and GATA‑3. In the present study, IPD intervention was demonstrated to ameliorate airway hyperreactivity and inflammation and the mechanisms may involve inhibition of the GATA‑3/IL‑5 signaling pathway.

Th2 cytokine inhibitor suplatast tosilate inhibits antigen-induced mucus hypersecretion in the nasal epithelium of sensitized rats

OBJECTIVES

Th2 cytokines such as interleukin (IL) 4 and IL-13 are potential mediators for mucus hypersecretion in allergic inflammation. To elucidate the functions of Th2 cytokines in allergic rhinitis, we examined the in vivo effects of the Th2 cytokine inhibitor suplatast tosilate on mucus hypersecretion and eosinophil infiltration in rat nasal epithelium.

METHODS

We induced hypertrophic and metaplastic changes in goblet cells in the nasal epithelium of ovalbumin-sensitized rats by intranasal challenge with ovalbumin. The effects of orally administered suplatast tosilate on mucus production and eosinophil infiltration were examined.

RESULTS

Suplatast tosilate (30 and 100 mg/kg) dose-dependently inhibited ovalbumin-induced mucus production and eosinophil infiltration. These suppressions of mucus production and eosinophil infiltration were only effective when suplatast tosilate was given in the effector phase; administration in the induction phase resulted in no effect.

CONCLUSIONS

These results indicate that Th2 cytokines are important mediators of mucus hypersecretion and eosinophil infiltration in allergic rhinitis. Suplatast tosilate may be useful for the treatment of allergic rhinitis by attenuating the inflammation of the effector phase.

Suplatast tosilate prevents bleomycin-induced pulmonary fibrosis in mice

Increasing evidence suggests that the development of pulmonary fibrosis is a T helper (Th) 2-mediated process. Suplatast tosilate is a Th2 cytokine inhibitor that is widely used as an asthma controller in Japan. Therefore, we hypothesized that suplatast tosilate might have an inhibitory effect on the development of pulmonary fibrosis. To investigate this effect, suplatast tosilate was administered to mice after the intratracheal instillation of bleomycin (BLM). The effect of suplatast tosilate was studied by analysis of bronchoalveolar lavage (BAL) fluid and a hydroxyproline assay. We found that the treatment of mice with suplatast tosilate significantly reduced the degree of pulmonary fibrosis. Because a significantly elevated Th2 response was not detected in the C57BL/6 mice after BLM administration, the effect of suplatast tosilate on Th2 cytokines could not be demonstrated. Interestingly, however, the up-regulation of the monocyte chemoattractant protein (MCP)-1 levels in the BAL fluid was found to be suppressed. Following these results, we also demonstrated that suplatast tosilate effectively inhibited the production of MCP-1 in alveolar macrophages (AMs). These findings suggest that suplatast tosilate has both anti-inflammatory and antifibrotic effects, which were associated with a suppressed MCP-1 expression in AMs. Thus, suplatast tosilate, which is already widely used in Japan, may warrant further consideration as a potentially useful treatment for pulmonary fibrosis.