EGFR activation-induced decreases in claudin1 promote MUC5AC expression and exacerbate asthma in mice.

Claudin1 plays a critical role in maintaining the epithelial barrier, and mucus hypersecretion induced by epidermal growth factor receptor (EGFR) activation is a pivotal pathological feature of asthma. The relationship between claudin1 expression and mucus hypersecretion and EGFR activation is still poorly understood. In this report, we showed that claudin1 expression correlated with asthma stage, in both patients with asthma and in the house dust mite (HDM)-induced mouse asthma model. Claudin1 knockdown induced MUC5AC overexpression both in 16HBE cells and in mouse airways. In addition, claudin1 expression negatively correlated with asthma severity as demonstrated by significantly higher MUC5AC expression, more severe airway inflammation, and increased airway hyperreactivity in mouse lungs with claudin1 knockdown following HDM challenge. EGFR activation reduced claudin1 expression and increased MUC5AC expression, both in vitro and in vivo. Erlotinib alleviated murine allergic airway inflammation, restored claudin1 expression and decreased MUC5AC expression. These results suggest that EGFR activation-induced decreases in claudin1 promote goblet-cell metaplasia, and restoring claudin1 to maintain barrier integrity by EGFR antagonism may provide a novel therapeutic strategy for asthma.

Formononetin attenuates atopic dermatitis by upregulating A20 expression via activation of G protein-coupled estrogen receptor.

ETHNOPHARMACOLOGICAL RELEVANCE: Atopic dermatitis (AD) is a complex skin disease with highly heterogeneous inflammation, which ranks among the largest component of the nonfatal diseases worldwide. The medications currently used to treat AD primarily include antihistamines, vitamin D and anti-inflammatory drugs, etc. But, the usage of these drugs is usually accompanied by various side-effects. Formononetin (FMN), a natural active ingredient of Astragalus membranaceus (Fisch.) Bunge, decreases the AD relapse rate, reduces recurring severity incidence and resists the inflammation in the initial stage of AD. However, the underlying mechanism of FMN on repressing the development of AD is still unknown. AIM OF THE STUDY: To investigate the potential mechanism of FMN on relieving the initial responses of AD and elucidate its possible therapeutic targets in vivo and in vitro. MATERIALS AND METHODS: A fluorescein isothiocyanate (FITC)-induced mouse model of the initial stage of AD was established in vivo. Human keratinocytes (HaCaT) cells were co-stimulated with tumor necrosis factor alpha (TNF-α) and polyinosinic-polycytidylic acid (Poly(I:C)) in vitro. The production of thymic stromal lymphopoietin (TSLP) and immunoglobulin E (IgE) were detected by enzyme-linked immunosorbnent assay (ELISA). The protein expression was measured through immunohistochemistry and western blotting. The mRNA expression was examined by real-time quantitative polymerase chain reaction (RT-qPCR). The impact of TNF-α-induced protein 3 (TNFAIP3/A20) was reflected using its small interfering RNA (siRNA). The role of G protein-coupled estrogen receptor (GPER) was explored using its agonist (G1), antagonist (G15) or siRNA (siGPER) in vitro. RESULTS: We found that FMN upregulated the expression of A20 protein and mRNA in the initial stage of AD model, especially in the epithelial region of ear tissue, and inhibited the production of TSLP simultaneously. Consistently, FMN significantly upregulated A20 protein and its mRNA expression while reduced TSLP protein and its mRNA expression in vitro, and this effect could be antagonized by A20 siRNA (siA20). Moreover, compared with PPT (ERα agonist) and DPN (ERß agonist), G1 could significantly increase the expression of A20. In addition, compared with MPP (ERα antagonist) and PHTPP (ERß antagonist), G15 could markedly reduce the expression of A20. Furthermore, the effects of FMN on A20 were interfered by siGPER and G15 in vitro and in vivo. CONCLUSIONS: These results demonstrated that FMN attenuated AD by upregulating A20 expression via activation of GPER. This new strategy might have effective therapeutic potential for AD and other inflammatory disorders.

Frontline Science: Two flavonoid compounds attenuate allergic asthma by regulating epithelial barrier via G protein-coupled estrogen receptor: Probing a possible target for allergic inflammation.

Allergic asthma is a common chronic lung inflammatory disease and seriously influences public health. We aim to investigate the effects of formononetin (FMN) and calycosin (CAL), 2 flavonoids in Radix Astragali, on allergic asthma and elucidate possible therapeutic targets. A house dust mite (HDM)-induced allergic asthma mouse model and TNF-α and Poly(I:C) co-stimulated human bronchial epithelial cell line (16HBE) were performed respectively in vivo and in vitro. The role of G protein-coupled estrogen receptor (GPER) was explored by its agonist, antagonist, or GPER small interfering RNA (siGPER). E-cadherin, occludin, and GPER were detected by western blotting, immunohistochemistry, or immunofluorescence. The epithelial barrier integrity was assessed by trans-epithelial electric resistance (TEER). Cytokines were examined by enzyme-linked immunosorbent assay (ELISA). The results showed that flavonoids attenuated pulmonary inflammation and hyperresponsiveness in asthmatic mice. These flavonoids significantly inhibited thymic stromal lymphopoietin (TSLP), increased occludin and restored E-cadherin in vivo and in vitro. The effects of flavonoids on occludin and TSLP were not interfered by ICI182780 (estrogen receptor antagonist), while blocked by G15 (GPER antagonist). Furthermore, compared with PPT (ERα agonist) and DPN (ERß agonist), G1 (GPER agonist) significantly inhibited TSLP, up-regulated occludin, and restored E-cadherin. siGPER and TEER assays suggested that GPER was pivotal for the flavonoids on the epithelial barrier integrity. Finally, G1 attenuated allergic lung inflammation, which could be abolished by G15. Our data demonstrated that 2 flavonoids in Radix Astragali could alleviate allergic asthma by protecting epithelial integrity via regulating GPER, and activating GPER might be a possible therapeutic strategy against allergic inflammation.

MicroRNA-155-5p is a key regulator of allergic inflammation, modulating the epithelial barrier by targeting PKIα.

Recent studies have demonstrated that microRNA-155-5p (miR-155-5p) plays an essential role in the regulation of allergen-induced inflammation and is overexpressed in the skin of patients with atopic dermatitis (AD), although the mechanism is unknown. In this study, silencing miR-155-5p attenuated the thickening of the epidermis in AD model and reduced the infiltration of inflammatory cells and the secretion of Th2 cytokines. Protein kinase inhibitor α (PKIα) was identified as a direct target of miR-155-5p and correlated negatively with miR-155-5p in our AD model. Fluorescence in situ hybridization showed that miR-155-5p-expressing cells were predominantly present in the epidermis. When epithelial cells were transfected with an miR-155-5p inhibitor, the expression of PKIα, occludin, and CLDN16 increased and that of TSLP decreased significantly, whereas the overexpression of miR-155-5p resulted in the opposite changes. The increased expression of PKIα and tight junction (TJ) proteins, with reduced TSLP and IL-33, was also detected in miR-155-5p-blocked mice, in both the initial and elicitation stages of AD. The expression of TJ proteins also decreased when cells were transfected with PKIα siRNA. TJ proteins increased and TSLP and IL-33 decreased significantly after the overexpression of PKIα. Our data provide the first evidence that miR-155-5p is critical for the allergic inflammation in a mouse model of AD by directly regulating PKIα and thus epithelial TJ expression. These findings suggest new therapeutic strategies that target miR-155-5p in patients with allergic disorders.

Huangqi-Fangfeng protects against allergic airway remodeling through inhibiting epithelial-mesenchymal transition process in mice via regulating epithelial derived TGF-ß1.

BACKGROUND: Long-term exposure to aeroallergens such as house dust mite (HDM) could result in airway inflammation and airway remodeling, characteristic features of allergic asthma. Huangqi-Fangfeng (HF), an important "couplet medicines" of Yu-Ping-Feng-San (YPFS), mediates allergen-induced airway inflammation in mice, but its role in the airway remodeling is not known. PURPOSE: To evaluate the effects of HF on airway remodeling of allergic asthma in a murine model and to investigate the underlying mechanisms in vivo and in vitro. METHODS: The main components of HF were analyzed by HPLC. The HDM-induced asthma mice model was established to study the effects of HF on airway inflammation and airway remodeling in vivo. Enhanced pause (Penh) index value was used as an indicator of airway hyper-reactivity. Bronchoalveolar lavage fluid (BALF) was processed for differential cell counting and determination of cytokines production. The lungs were fixed in 4% paraformaldehyde for histological examination after staining with H&E, trichrome and IHC. Production of interleukin (IL)-4, IL-5, IL-13, and transforming growth factor beta-1 (TGF-ß1) in BALF and lung tissues, IgE in serum were measured by ELISAs. Expression of epithelial markers and mesenchymal markers were detected by immunohistochemistry and western blots. The effects of HF and its components on epithelial-mesenchymal transition (EMT) were detected in human bronchial epithelial cells (16HBE) treated with TGF-ß1 and HDM. RESULTS: The main components of Huangqi-Fangfeng detected by HPLC were Calycosin, Formononetin and Cimifugin. In HDM-induced allergic asthma mice model, respiratory exposure to HDM lead to airway hyperresponsiveness and thickening of the smooth muscle layer in the airway. TGF-ß1 levels increased in mice airways while epithelial cells lost expression of E-cadherin and gained expression of the mesenchymal proteins N-cadherin, α-SMA and collagen І. These changes were relieved by treatment with HF. Furthermore, restored epithelial markers expression treated with individual components were also detectable in 16HBE cells. CONCLUSION: These results demonstrated that Huangqi-Fangfeng protected against allergic airway remodeling through inhibiting epithelial-mesenchymal transition process in mice via regulating epithelial derived TGF-ß1.

A Chinese Prescription Yu-Ping-Feng-San Administered in Remission Restores Bronchial Epithelial Barrier to Inhibit House Dust Mite-Induced Asthma Recurrence.

Clinically, the treatments against asthma like ß2 agonist focus on controlling the symptoms rather than inhibiting recurrence radically. This study aims to evaluate the efficacy and mechanism of a potent Chinese prescription Yu-Ping-Feng-San (YPFS) against asthma recurrence. We here established an optimized house dust mite (HDM)-induced asthma recurrence mice model with typical asthmatic responses such as significantly augmented airway hyperresponsiveness (AHR), elevated serum IgE, pulmonary type 2 cytokines IL-5 and IL-13 levels, pathological changes including thickening bronchial wall, inflammatory infiltration of lung tissue, etc. Moreover, all typical asthmatic pathological features were prominently alleviated by YPFS applied during remission phase ahead of second elicitation, which was even more effective than three different types of medications dexamethasone, montelukast and salbutamol, which were commonly applied in clinical practice, administered during recurrence phase. Besides, we found that desmoglein 1 (DSG1) remained deficient when asthmatic responses regressed whereas tight junction (TJ) claudin 1 (CLDN1) or adherin junction (AJ) E-cadherin restored spontaneously. In vitro, DSG1 interference resulted in increased thymic stromal lymphopoietin (TSLP) secretion, and epithelial barrier compromise evidenced by significantly elevated transepithelial electrical resistance (TEER) and increased 4-kDa FITC-dextran influx. YPFS could downregulate TSLP production and restore HDM-induced DSG1 deficiency and barrier destruction, which was further reversed by shDSG1. Collectively, administration of YPFS in remission prominently alleviated HDM-induced asthma relapse by restoring DSG1 and decreasing TSLP overexpression, which might be the key factors contributing to chronic asthma relapse. Our data not only demonstrated the pivotal role of DSG1 in asthma pathogenesis, but also provided a novel and potent therapeutic strategy against chronic asthma.

Synthesis, Anti-Varicella-Zoster Virus and Anti-Cytomegalovirus Activity of 4,5-Disubstituted 1,2,3-(1H)-Triazoles.

BACKGROUND: Clinical drugs for herpesvirus exhibit high toxicity and suffer from significant drug resistance. The development of new, effective, and safe anti-herpesvirus agents with different mechanisms of action is greatly required. OBJECTIVE: Novel inhibitors against herpesvirus with different mechanisms of action from that of clinical drugs. METHODS: A series of novel 5-(benzylamino)-1H-1,2,3-triazole-4-carboxamides were efficiently synthesized and EC50 values against Human Cytomegalovirus (HCMV), Varicella-Zoster Virus (VZV) and Herpes Simplex Virus (HSV) were evaluated in vitro. RESULTS: Some compounds present antiviral activity. Compounds 5s and 5t are potent against both HCMV and VZV. Compounds 5m, 5n, 5s, and 5t show similar EC50 values against both TK+ and TK- VZV strains. CONCLUSION: 5-(Benzylamino)-1H-1, 2,3-triazole-4-carboxamides are active against herpesviruses and their activity is remarkably affected by the nature and the position of substituents in the benzene ring. The results indicate that these derivatives are independent of the viral thymidine kinase (TK) for activation, which is indispensable for current drugs. Their mechanisms of action may differ from those of the clinic anti-herpesvirus drugs.

Modification Targeting the "Rana Box" Motif of a Novel Nigrocin Peptide From Hylarana latouchii Enhances and Broadens Its Potency Against Multiple Bacteria.

Public health is confronting the threat caused by antibiotic resistance and this means new antibacterial strategies must be developed urgently. Antimicrobial peptides (AMPs) have been considered as promising therapeutic candidates against infection in the post-antibiotic era. In this paper, we dismissed the significance of "Rana box" in the natural nigrocin-HL identified from skin secretion of Hylarana latouchii by comparing its activity with nigrocin-HLD without the motif. By substituting the "Rana box" sequence with an amidated phenylalanine residue, the natural peptide was modified into a shorter AMP nigrocin-HLM. Activities and toxicities of these two peptides in vitro and in vivo were compared. As a result, nigrocin-HLM not only displayed significantly increased potency against several representative microbes, but also high activity against the antibiotic-resistant methicillin-resistant S. aureus (MRSA, NCTC 12493 and ATCC43300 and several clinical isolates) as evidenced by markedly reduced minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC). More strikingly, nigrocin-HLM exhibited prominent inhibition against MRSA infection in a pneumonia mice model. In addition, the substitution attenuated the toxicity of nigrocin-HLM as evidenced by precipitously decreased hemolytic and cytotoxic activities in vitro, and acute toxicity to mice in vivo. Taken these results into consideration, nigrocin-HLM should be a promising therapeutic candidate for anti-infection. And in addition to dismiss an indispensable role of "Rana box" in maintaining antimicrobial activity of nigrocin-HL, our data provided an inspired strategy for peptide optimization.

[Seasonal variation of Cyclobalanopsis glauca whole-tree transpiration in karst region].

By using Granier's sap-flow method, the variations of sap flux density and whole-tree transpiration of Cyclobalanopsis glauca (syn. Quercus glauca) on a hilly slope in the karst region of South China were studied, with their driving factors analyzed. The sap flux density (Js) of C. glauca varied randomly with the diameter of breast height of individual trees, and its maximum occurred at 13:30-14:30. In a seasonal course, the daily Js was the maximum (56.00 g H2O x m(-2) x s(-1)) in summer, and the minimum (35.86 g H2O x m(-2) x s(-1)) in spring. The daily whole-tree transpiration had a greater change with weather condition, representing a power functional relationship with vapor pressure deficit (VPD) and photosynthesically active radiation (PAR) (R = 0.97, P < 0.01). The average daily whole-tree transpiration tended to be high in summer and low in winter and spring, and decreased with the decrease of soil moisture content in autumn (drought season). However, comparing with that of the tree species in other regions, the daily whole-tree transpiration amount of C. glauca in study region was still higher, even though the weather was dry and the soil was thin. It was presumed that in the dry season in karst region, the water supply for C. glauca could be mainly depended on the water-rich epikarst.