The inhibition of aldose reductase on mucus production induced by interleukin-13 in the human bronchial epithelial cells

Gleditsia sinensis Lam. aqueous extract attenuates nasal inflammation in allergic rhinitis by inhibiting MUC5AC production through suppression of the STAT3/STAT6 pathway

Allergic rhinitis (AR), a chronic respiratory inflammatory disease, is among the most common chronic diseases reported worldwide. Mucus hypersecretion is a critical feature of AR pathogenesis. Although the Gleditsia sinensis extract has several beneficial effects on human health, its effects on allergic inflammation have not yet been investigated. In this study, we examined the effects of G. sinensis aqueous extract (GSAE) on nasal inflammation in an ovalbumin (OVA)-induced AR mouse model. GSAE was administered orally for 1 week and then the clinical nasal symptoms were evaluated. The levels of histamine, OVA-specific immunoglobulin (Ig) E, and interleukin (IL)-13 were measured in the serum using an enzyme-linked immunosorbent assay (ELISA). Inflammatory cells were then counted in the nasal lavage fluid (NALF) and histopathology in the nasal epithelium was evaluated. STAT3/STAT6 phosphorylation was examined in primary human nasal epithelial cells (HNEpCs) using western blot analysis. Oral administration of GSAE to OVA-induced AR mice alleviated nasal clinical symptoms and reduced OVA-specific immunoglobulin E, interleukin (IL)-13, and histamine levels. The accumulation of eosinophils in nasal lavage fluid, nasal mucosa, mast cells, goblet cells, and mucin 5AC (MUC5AC) in the nasal epithelium was also inhibited by GSAE. Treatment with GSAE inhibited the production of MUC5AC in IL-4/IL-13-stimulated primary human nasal epithelial cells through the signal transducer and activator of transcription (STAT)3/STAT6 signaling pathway. These results indicated that GSAE reduces nasal inflammation suggesting that it is a potential treatment option for AR.

Psoralen inhibits the inflammatory response and mucus production in allergic rhinitis by inhibiting the activator protein 1 pathway and the downstream expression of cystatin‑SN

Psoralen (PSO) exerts anti-inflammatory pharmacological effects and plays an important role in a variety of inflammatory diseases. However, the effects of PSO with allergic rhinitis (AR) are yet to be reported. In the present study, an in vitro AR model was generated by inducing JME/CF15 human nasal epithelial cells with IL-13, after which MTT was used to assess the cytotoxicity of PSO. The expression levels of inflammatory cytokines (granulocyte-macrophage colony-stimulating factor and Eotaxin) were determined by ELISA. Furthermore, the expression of inflammatory IL-6 and −8, as well as mucin 5AC, was assessed by reverse transcription-quantitative PCR and western blotting, and cellular reactive oxygen species were detected using a 2′,7′-dichlorodihydrofluorescein diacetate fluorescent probe. Western blotting was also used to detect the expression and phosphorylation of c-Fos and c-Jun in the activator protein 1 (AP-1) pathway, as well as the expression of cystatin-SN (CST1). PSO inhibited the inflammatory response and mucus production in IL-13-induced JME/CF15 cells. Furthermore, the levels of c-Fos and c-Jun phosphorylation in the AP-1 pathway were decreased in IL-13-induced JME/CF15 cells following PSO treatment. The expression of pathway proteins was activated by the addition of PMA, an AP-1 pathway activator, which concurrently reversed the inhibitory effects of PSO on the inflammatory response and mucus formation. The addition of an AP-1 inhibitor (SP600125) further inhibited pathway activity, and IL-13-induced inflammation and mucus formation was restored. In conclusion, PSO regulates the expression of CST1 by inhibiting the AP-1 pathway, thus suppressing the IL-13-induced inflammatory response and mucus production in nasal mucosal epithelial cells.

Development of Aldose Reductase Inhibitors for the Treatment of Inflammatory Disorders and Cancer: Current Drug Design Strategies and Future Directions

Aldose Reductase (AR) is an enzyme that converts glucose to sorbitol during the polyol pathway of glucose metabolism. AR has been shown to be involved in the development of secondary diabetic complications due to its involvement in causing osmotic as well as oxidative stress. Various AR inhibitors have been tested for their use to treat secondary diabetic complications, such as retinopathy, neuropathy, and nephropathy in clinical studies. Recent studies also suggest the potential role of AR in mediating various inflammatory complications. Therefore, the studies on the development and potential use of AR inhibitors to treat inflammatory complications and cancer besides diabetes are currently on the rise. Further, genetic mutagenesis studies, computer modeling, and molecular dynamics studies have helped design novel and potent AR inhibitors. This review discussed the potential new therapeutic use of AR inhibitors in targeting inflammatory disorders and cancer besides diabetic complications. Further, we summarized studies on how AR inhibitors have been designed and developed for therapeutic purposes in the last few decades.

Leptin positively regulates MUC5AC production and secretion induced by interleukin-13 in human bronchial epithelial cells

Mucus hypersecretion and plugging of lower respiratory tract airways due to mucus plugs have long been recognized as the leading cause of the morbidity and mortality in asthma. MUC5AC protein is a major component of airway mucus. Here, we showed that interleukin (IL)-13 induced MUC5AC production and secretion, and leptin expression in the human bronchial epithelial cell line-16 (HBE16) cells in a concentration-dependent manner. Leptin knockdown suppressed MUC5AC production and secretion induced by IL-13. We further investigated the molecular mechanism by which leptin functioned, and found that leptin regulated IL-13-induced MUC5AC production and secretion via the JAK2-STAT3 pathway. Subsequently, Munc18b, a limiting component of the exocytic machinery of airway epithelial and mast cells, was found that when knockdown, MUC5AC secretion was significantly inhibited. SABiosciences ChIP search tool identified three STAT3 binding sites with Munc18b promoter. Chromatin immunoprecipitation analysis further confirmed that Stat3 upregulated Munc18b expression by directly binding to its promoter. These data suggested that leptin promotes MUC5AC secretion via JAK2-STAT3-MUNC18b regulatory network. Taken together, our data highlight a positive feedback role and molecular mechanism for leptin in the control of MUC5AC production and secretion from airway epithelial cells stimulated by IL-13, which encourage further exploration of the therapeutic potentials of manipulating leptin in the treatment of mucus hypersecretion in chronic inflammation lung diseases.

A systems pharmacology approach to investigate the mechanisms of action of Semen Strychni and Tripterygium wilfordii Hook F for treatment of rheumatoid arthritis

ETHNOPHARMACOLOGY RELEVANCE

The angiogenesis control at the initiation of rheumatoid arthritis (RA) that mainly blocks the inflammatory cascades expects to attenuate the action of angiogenic mediators, synovial angiogenesis, and to partially reverse the erosive bone damage. Two typical Chinese herbs, Semen Strychni and Tripterygium wilfordii Hook F (TwHF) have been used as a remedy to treat RA since ancient time. However, their functioning mechanisms are still unknown. Thus it is necessary to exploit their underlying mechanism for the treatment of RA.

METHODS

This study was undertaken to analyze their underlying mechanism based on a systems biology platform. Firstly, active components of the two herbs were screened out from TcmSP database based on their OB and DL values. Then their potential targets were predicted by using Random Forest, Support Vector Machine, and validated via docking process. Finally, a network of compound-target was constructed.

RESULTS

In this work, 27 and 33 active compounds were screened out from Semen Strychni and TwHF, targeting 28 and 32 potential proteins, respectively. The results show that the two herbs modulate the angiogenesis mediators through both direct and indirect pathways, and 21 common targets shared by Semen Strychni and TwHF bear major responsibility for treating RA.

CONCLUSIONS

The underlying mechanism of Semen Strychni and TwHF in treatment of RA is through multiple targets interaction by their blocking of the angiogenesis mediator cascades. This may provide us a better understanding of the function of the two herbs for the treatment of RA, as well as a clue to unveil their possible treatment effects of other systemic diseases, and in this way, hopefully the screening models may facilitate the discovery of novel combined drugs.

IL13 activates autophagy to regulate secretion in airway epithelial cells

Cytokine modulation of autophagy is increasingly recognized in disease pathogenesis, and current concepts suggest that type 1 cytokines activate autophagy, whereas type 2 cytokines are inhibitory. However, this paradigm derives primarily from studies of immune cells and is poorly characterized in tissue cells, including sentinel epithelial cells that regulate the immune response. In particular, the type 2 cytokine IL13 (interleukin 13) drives the formation of airway goblet cells that secrete excess mucus as a characteristic feature of airway disease, but whether this process is influenced by autophagy was undefined. Here we use a mouse model of airway disease in which IL33 (interleukin 33) stimulation leads to IL13-dependent formation of airway goblet cells as tracked by levels of mucin MUC5AC (mucin 5AC, oligomeric mucus/gel forming), and we show that these cells manifest a block in mucus secretion in autophagy gene Atg16l1-deficient mice compared to wild-type control mice. Similarly, primary-culture human tracheal epithelial cells treated with IL13 to stimulate mucus formation also exhibit a block in MUC5AC secretion in cells depleted of autophagy gene ATG5 (autophagy-related 5) or ATG14 (autophagy-related 14) compared to nondepleted control cells. Our findings indicate that autophagy is essential for airway mucus secretion in a type 2, IL13-dependent immune disease process and thereby provide a novel therapeutic strategy for attenuating airway obstruction in hypersecretory inflammatory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis lung disease. Taken together, these observations suggest that the regulation of autophagy by Th2 cytokines is cell-context dependent.

Development of aldose reductase inhibitors for the treatment of inflammatory disorders

INTRODUCTION

Accumulating evidence attributes a significant role to aldose reductase (ALR2) in the pathogenesis of several inflammatory pathologies. Aldose reductase inhibitors (ARIs) were found to attenuate reactive oxygen species (ROS) production both in vitro and in vivo. Thus, they disrupt signaling cascades that lead to the production of cytokines/chemokines, which induce and exacerbate inflammation. As a result, ARIs might hold a significant therapeutic potential as alternate anti-inflammatory drugs.

AREAS COVERED

The authors present a comprehensive review of the current data that support the central role of ALR2 in several inflammatory pathologies (i.e., diabetes, cancer, sepsis, asthma and ocular inflammation). Further, the authors describe the potential underlying molecular mechanisms and provide a commentary on the status of ARIs in this field.

EXPERT OPINION

It is important that future efforts focus on delineating all the steps of the molecular mechanism that implicates ALR2 in inflammatory pathologies. At the same time, utilizing the previous efforts in the field of ARIs, several candidates that have been proven safe in the clinic may be evaluated for their clinical significance as anti-inflammatory medication. Finally, structurally novel ARIs, designed to target specifically the proinflammatory subpocket of ALR2, should be pursued.

EBM84 attenuates airway inflammation and mucus hypersecretion in an ovalbumin-induced murine model of asthma

EBM84 is a traditional herbal medicine and a combination of extracts obtained from Pinellia ternata and Zingiber officinale. It is traditionally used to treat vomiting, nausea, sputum and gastrointestinal disorders, and functions is an effective expectorant. In this study, we evaluated the protective effects of EBM84 on asthmatic responses, particularly mucus hypersecretion in an ovalbumin (OVA)-induced murine model of asthma. We also analyzed EBM84 composition using high performance liquid chromatography. Animals were sensitized on days 0 and 14 via intraperitoneal injection using 20 µg OVA. On days 21, 22 and 23 after initial sensitization, the mice received an airway challenge with OVA (1% w/v in PBS) for 1 h using an ultrasonic nebulizer (NE-U12). EBM84 was administered by gavage to the mice at doses of 16.9, 33.8 and 67.5 mg/kg once daily from days 18 to 23. EBM84 administration significantly lowered elevated levels of interleukin (IL)-4, IL-13, eotaxin and immunoglobulin (Ig)E in the bronchoalveolar lavage fluid or plasma. Airway inflammation and mucus hypersecretion were attenuated following EBM84 administration. EBM84 also inhibited the overexpression of mucin 5AC (MUC5AC) induced by OVA challenge in lung tissue. This result was consistent with the immunohistochemistry results. Our results indicate that EBM84 effectively inhibited airway inflammation and mucus hypersecretion via the downregulation of T helper 2 (Th2) cytokines, which reduced MUC5AC expression. Therefore, EBM84 has potential as a useful medicine for the treatment of allergic asthma.