Osthole treatment ameliorates Th2-mediated allergic asthma and exerts immunomodulatory effects on dendritic cell maturation and function

Near Infrared-Triggered Nitric Oxide-Release Nanovesicles with Mild-Photothermal Antibacterial and Immunomodulation for Healing MRSA-Infected Diabetic Wounds

Bacterial infection-induced excessive inflammation is a major obstacle in diabetic wound healing. Nitric oxide (NO) exhibits significant antibacterial activity but is extremely deficient in diabetes. Hence, a near-infrared (NIR)-triggered NO release system is constructed through codelivery of polyarginine (PArg) and gold nanorods (Au) in an NIR-activatable methylene blue (MB) polypeptide-assembled nanovesicle (Au/PEL-PBA-MB/PArg). Upon NIR irradiation, the quenched MB in the nanovesicles is photoactivated to generate more reactive oxygen species (ROS) to oxidize PArg and release NO in an on-demand controlled manner. With the specific bacterial capture of phenylboronic acid (PBA), NO elevated membrane permeability and boosted bacterial vulnerability in the photothermal therapy (PTT) of the Au nanorods, which is displayed by superior mild PTT antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) at temperatures < 49.7 °C in vitro. Moreover, in vivo, the antibacterial nanovesicles greatly suppressed the burst of MRSA-induced excessive inflammation, NO relayed immunomodulated macrophage polarization from M1 to M2, and the excessive inflammatory phase is successfully transferred to the repair phase. In cooperation with angiogenesis by NO, tissue regeneration is accelerated in MRSA-infected diabetic wounds. Therefore, nanoplatform has considerable potential for accelerating the healing of infected diabetic wounds.

Osthole exhibits the remedial potential for polycystic ovary syndrome mice through Nrf2-Foxo1-GSH-NF-κB pathway

Polycystic ovary syndrome (PCOS) is the primary cause of female infertility with a lack of universal therapeutic regimen. Although osthole exhibits numerous pharmacological activities in treating various diseases, its therapeutic effect on PCOS is undiscovered. The present study found that application of osthole improved the symptoms of PCOS mice through preventing ovarian granulosa cells (GCs) production of more estrogen and alleviating the liberation of pro-inflammatory cytokine interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha. Meanwhile, osthole enhanced ovarian antioxidant capacity and alleviated intracellular reactive oxygen species (ROS) accumulation with a concurrent attenuation for oxidative stress, while intervention of antioxidant enzymic activity and glutathione (GSH) synthesis neutralized the salvation of osthole on GCs secretory disorder and chronic inflammation. Further analysis revealed that osthole restored the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and forkhead box O 1 (Foxo1) whose repression antagonized the amelioration of osthole on the insufficiency of antioxidant capacity and accumulation of ROS. Moreover, Nrf2 served as an intermedium to mediate the regulation of osthole on Foxo1. Additionally, osthole restricted the phosphorylation of IκBα and nuclear factor kappa B (NF-κB) subunit p65 by DHEA and weakened the transcriptional activity of NF-κB, but this effectiveness was abrogated by the obstruction of Nrf2 and Foxo1, whereas adjunction of GSH renewed the redemptive effect of osthole on NF-κB whose activation caused an invalidation of osthole in rescuing the aberration of GCs secretory function and inflammation response. Collectively, osthole might relieve the symptoms of PCOS mice via Nrf2-Foxo1-GSH-NF-κB pathway.

The Effect of Osthole on Transient Receptor Potential Channels: A Possible Alternative Therapy for Atopic Dermatitis

Introduction

Chronic recurrent skin inflammation and severe itching in patients with atopic dermatitis (AD) significantly impair their quality of life. The H4 histamine receptor plays a key role in histamine-induced itching. During the skin inflammation associated with AD, pro-inflammatory mediators (interleukins, cytokines) are released from neurons. Ultimately, a cascade of reactions leads to the activation and sensitization of transient receptor potential channels (TRP), which exacerbate the inflammation and itching associated with AD. Osthole (OST) is a natural coumarin with a proven versatile pharmacological effect: anti-cancer, anti-inflammatory and immunomodulatory. However, the molecular mechanism of OST in relieving inflammation in histamine-mediated itching is not yet clear.

Purpose

In the studies presented, the possible effect of the OST action on the inhibition of the gene expression of the histamine H4 receptor and the key genes of the TRP channels as well as on the concentration of proinflammatory interleukins was analyzed.

Methods

Inflammation was induced in a 3D skin model and a keratinocyte cell line Normal Human Epidermal Keratinocytes (NHEK) identical to that of AD, and then OST was administered at various doses. The concentrations of IL-4/-13 were determined by ELISA. RNA was isolated from the 3D skin cells and the NHEK cell line, and the qPCR method was used to determine the expression of: IL-4α, H4R, TRPV1, TRPV4, TRPM8 analyzed.

Results

The study showed that OST significantly reduced the secretion of IL-4/-13 in a keratinocyte cell line and in a 3D skin model. In addition, OST was found to significantly decrease the gene expression of IL-4α, H4R, TRPV1, TRPV4 and increase TRPM8 in both the NHEK cell line and the organotypic 3D skin model.

Conclusion

The data obtained provide the first in vitro evidence of itch relief following the application of OST to atopic skin. Research on the use of OST as an active component of emollients in the treatment of AD should be continued in the future.

Effects of "Shi Ying Zi" powder and osthole on immune and antioxidant function of Eimeria tenella-infected broilers

"Shi Ying Zi" powder is a traditional Chinese herbal formula for preventing and treating coccidiosis. In our previous studies, it showed anticoccidial effects and exhibited the potential to control Eimeria tenella infection. In this research, we evaluated the antioxidation and immune effect of "Shi Ying Zi" powder and its effective active ingredient osthole on coccidiosis-infected broilers to explore the mechanism of its anticoccidial effect. We analyzed changes in the antioxidant index, the pathological changes in cecum, immune index of serum and composition of cecal flora. The results showed that the use of "Shi Ying Zi" powder and osthole alleviated the pathological changes in the cecum, spleen and bursa of Fabricius, upregulated the spleen and bursal weigh index. "Shi Ying Zi" powder of 10 g/kg effectively rocovered the contents of interleukins and immunoglobulin in serum. Osthole increased the proportion of Firmicutes, Actino-bacteria and Lactobacillus in the cecum. In summary, "Shi Ying Zi" powder and osthole have anticoccidial effects, and they also can active the immunity, antioxidant functions and upregulate the beneficial bacteria population in Eimeria tenella-infected broilers.

Osthole regulates N6-methyladenosine-modified TGM2 to inhibit the progression of rheumatoid arthritis and associated interstitial lung disease

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease, and RA interstitial lung disease (ILD) is a severe complication of RA. This investigation aims to determine the effect and underlying mechanism of osthole (OS), which could be extracted from Cnidium, Angelica, and Citrus plants and evaluate the role of transglutaminase 2 (TGM2) in RA and RA-ILD. In this work, OS downregulated TGM2 to exert its additive effect with methotrexate and suppress the proliferation, migration, and invasion of RA-fibroblast-like synoviocytes (FLS) by attenuating NF-κB signaling, resulting in the suppression of RA progression. Interestingly, WTAP-mediated N6-methyladenosine modification of TGM2 and Myc-mediated WTAP transcription cooperatively contributed to the formation of a TGM2/Myc/WTAP-positive feedback loop through upregulating NF-κB signaling. Moreover, OS could downregulate the activation of the TGM2/Myc/WTAP-positive feedback circuit. Furthermore, OS restrained the proliferation and polarization of M2 macrophages to inhibit the aggregation of lung interstitial CD11b⁺ macrophages, and the effectiveness and non-toxicity of OS in suppressing RA and RA-ILD progression were verified in vivo. Finally, bioinformatics analyses validated the importance and the clinical significance of the OS-regulated molecular network. Taken together, our work emphasized OS as an effective drug candidate and TGM2 as a promising target for RA and RA-ILD treatment.

Osthole Inhibits M1 Macrophage Polarization and Attenuates Osteolysis in a Mouse Skull Model

Excessive bone resorption due to increased inflammatory factors is a common feature of inflammatory lytic bone diseases. This group of diseases is effectively treated with drugs. In recent years, many studies have reported that traditional Chinese medicine herbs have substantial effects on inflammation, osteoclast differentiation and maturation, and bone destruction. Herein, we investigated the effects of osthole (OST) on lipopolysaccharide- (LPS-) induced macrophage polarization, inflammatory responses, and osteolysis. In vitro, we used immunofluorescence and quantitative real-time polymerase chain reaction assays to confirm whether bone marrow-derived macrophages showed an increased expression of inflammatory factors, such as interleukin-6, iNOS, CCR7, and CD86, in the presence of LPS. However, we found that such expression was suppressed and that the M2 macrophage expression increased in the presence of OST. OST reduced LPS- and RANKL-induced intracellular reactive oxygen species production in the bone marrow-derived macrophages. Further, it potently suppressed osteoclast differentiation and osteoclast-specific gene expression by suppressing the P38/MAPK and NF-κB pathways. Consistent with the in vitro observations, OST greatly ameliorated LPS-induced bone resorption and modulated the ratio of macrophages at the site of osteolysis. Taken together, OST has great potential for use in the management of osteolytic diseases.

The Role of Osthole on TGF-β-Induced Lung Epithelium Apoptosis Injury and Epithelial-Mesenchymal Transition-Mediated Airway Remodeling in Pediatric Asthma

Osthole, a coumarin compound derived from Fructus Cnidii, exerts anti-inflammatory effects in an asthma model. But the effect of osthole on epithelial injury and epithelial-mesenchymal transition (EMT) in asthma remains unclear. 16HBE cells were incubated with TGF-β1 with or without osthole in vitro. Ovalbumin (OVA)-induced asthmatic mouse model was established in vivo. Cell counting kit-8 was carried out to evaluate the viability of 16HBE cells. The impact of osthole on TGF-β1-evoked cell apoptosis and EMT process was measured by flow cytometry based on Annexin V-FITC/PI staining, transwell assay, immunofluorescence, and Western blot. The regulatory role of osthole in TGF-β1/Smad and p38, ERK1/2, and JNK MAPK signaling was detected via Western blot. Osthole treatment significantly suppressed TGF-β1-induced 16HBE cell apoptosis, verified by a reduced percentage of apoptotic cells, decreased expression of proapoptotic proteins (cleaved-caspase3 and Bax), and enhanced antiapoptotic factor (Bcl-2) expression. In addition, the promotive impact of TGF-β1 on the migration of 16HBE cells was reversed by osthole, accompanied by elevated E-cadherin expression and reduced Snail and N-cadherin expression. The activation of the Smad2/3 and MAPKs pathway evoked by TGF-β1 was inhibited by osthole in 16HBE cells. We also found that osthole mitigated airway epithelium injury and subepithelial fibrosis in OVA-challenged asthmatic mice in vivo. Osthole could mitigate TGF-β1-induced epithelial cell injury and EMT process by suppressing the activation of MAPK and Smad2/3 pathways separately. Our present study showed a new insight into understanding the underlying mechanism of osthole injury on epithelium injury and subepithelial fibrosis in airway remodeling. Asthma, epithelial injury, epithelial-mesenchymal transition, and airway remodeling are the effects of osthole on airway remodeling.

Computational Screening of the Natural Product Osthole and Its Derivates for Anti-Inflammatory Activity

Osthole (OS) is a natural coumarin with a long history of medicinal use in a variety of diseases, such as itch and menstrual disorders. In recent years, OS has been shown to treat inflammation and reduce the expression and activity of NF-κB, although its mechanism of action is still unclear. Overexpression of inflammatory cytokines can have many negative effects in the body, including inducing preterm labor; thus, the modulation of inflammation by OS and its derivatives may be able to delay preterm birth, increasing neonatal survival rates. The objectives of this study were to screen and identify the derivatives of OS with the highest potential for binding capacity to inflammatory mediators NF-κB, TNF-α, and ERK1, and to measure the drug-like properties of these compounds. GLIDE docking in Schrodinger Maestro software was used to calculate docking scores for a variety of semi-synthetic OS derivatives against three proteins involved in inflammation: NF-κB, TNF-α, and ERK1. Schrodinger Qikprop was also used to measure the pharmaceutically relevant properties of the compounds. The protonated demethoxy osthole 1 showed the highest docking of all the proteins tested, while the deprotonated demethoxy osthole 2 consistently had the lowest scores, denoting the importance of pH in the binding activity of this derivative. The lowest docking was at NF-κB, suggesting that this is less likely to be the primary target of OS. All of the screened derivatives showed high drug potential, based on their Qikprop properties. OS and its derivatives showed potential to bind to multiple proteins that regulate the inflammatory response and are prospective candidates for delaying preterm birth.

CCR3 gene knockout in bone marrow cells ameliorates combined allergic rhinitis and asthma syndrome (CARAS) by reducing airway inflammatory cell infiltration and Th2 cytokines expression in mice model

The present study aims to investigate the effects of CCR3 gene knockout in bone marrow cells (CCR3-KO) on the mouse model of combined allergic rhinitis and asthma syndrome (CARAS). It was found that CCR3-KO significantly reduced eosinophil (EOS) migration into the nasal (NALF) and bronchoalveolar (BALF) cavities of mice, and decreased Th2 cytokines (such as, IL-4, IL-5 and IL-13) levels in nasal mucosa and lung tissues. In addition, histological analysis showed that the damage degree of nasal mucosa structure in ovalbumin (OVA) modulated CCR3-KO mice was significantly less than that in OVA modulated Wild type (WT) mice, with reduced inflammatory cell infiltration and nasal mucus secretion. The infiltration of inflammatory cells in lung tissue was significantly reduced, and the proliferation of lung smooth muscle layer and extracellular matrix (ECM) production were decreased. Symptom analysis showed that CCR3-KO can reduced allergic rhinitis (AR) signals as nose scratching and sneezing. It was also found CCR3-KO reduce OVA-induced weight loss. The results showed that CCR3-KO could reduce the symptoms of allergic inflammation in CARAS mice by reducing airway inflammatory cell infiltration and down-regulating the expression of Th2 cytokines, and CCR3 gene could be used as a target gene for the treatment of CARAS.

Changes in the phenotype and function of mucosal-associated invariant T cells in neutrophilic asthma

Asthma is a chronic heterogeneous inflammatory disease. Most neutrophilic asthma (NA) cases are severe asthma involving many inflammatory cells and mediators, although the specific pathogenesis is not clear. Mucosal-associated invariant T (MAIT) cells as innate-like T lymphocytes play an important role in the immune response in asthma by producing cytokines. In this study, we evaluated the phenotype and function of circulating MAIT cells in patients with NA and inflammatory-related cytokines in plasma and induced sputum supernatants using flow cytometry. The results showed that the frequency of circulating MAIT cells in asthma patients, particularly NA patients, decreased significantly, and CD8⁺ MAIT and MAIT Temra cells also decreased significantly. Increased expression of CD69 and PD-1 on MAIT cells indicated excessive activation and depletion, leading to the decrease in MAIT cells. Levels of IL-17A and TNF-α secreted by MAIT cells of NA patients increased, whereas IFN-γ levels decreased, indicating that MAIT cells in NA are biased to the Th17 subtype. MAIT cells were also negatively correlated with clinical parameters, indicating that these cells are related to asthma severity. Pro-inflammatory cytokines in plasma and sputum supernatant increased to varying degrees, whereas IL-10 declined, corresponding with asthma severity. We speculate that increased IL-17A and TNF-α synergistically stimulated respiratory epithelial cells to secrete IL-6 and IL-8, thereby recruiting neutrophils to inflammatory sites and aggravating asthma symptoms. Therefore, MAIT cells could serve as a potential therapeutic target in NA immunity, thus providing a new strategy for the treatment of asthma.

Ligands and Signaling of Mas-Related G Protein-Coupled Receptor-X2 in Mast Cell Activation

Mas-related G protein-coupled receptor-X2 (MRGPRX2) is known as a novel receptor to activate mast cells (MCs). MRGPRX2 plays a dual role in promoting MC-dependent host defense and immunomodulation and contributing to the pathogenesis of pseudo-allergic drug reactions, pain, itching, and inflammatory diseases. In this article, we discuss the possible signaling pathways of MCs activation mediated by MRGPRX2 and summarize and classify agonists and inhibitors of MRGPRX2 in MCs activation. MRGPRX2 is a low-affinity and low-selectivity receptor, which allows it to interact with a diverse group of ligands. Diverse MRGPRX2 ligands utilize conserved residues in its transmembrane (TM) domains and carboxyl-terminus Ser/Thr residues to undergo ligand binding and G protein coupling. The coupling likely initiates phosphorylation cascades, induces Ca²⁺ mobilization, and causes degranulation and generation of cytokines and chemokines via MAPK and NF-κB pathways, resulting in MCs activation. Agonists of MRGPRX2 on MCs are divided into peptides (including antimicrobial peptides, neuropeptides, MC degranulating peptides, peptide hormones) and nonpeptides (including FDA-approved drugs). Inhibitors of MRGPRX2 include non-selective GPCR inhibitors, herbal extracts, small-molecule MRGPRX2 antagonists, and DNA aptamer drugs. Screening and classifying MRGPRX2 ligands and summarizing their signaling pathways would improve our understanding of MRGPRX2-mediated physiological and pathological effects on MCs.

Ameliorative effects of total coumarins from the fructus of Cnidium monnieri (L.) Cuss. on 2,4-dinitrochlorobenzene-induced atopic dermatitis in rats

Atopic dermatitis (AD), which is characterized by intense pruritus and serious inflammation, is a chronic skin disease. Modern studies have testified that the total coumarins from the fructus of Cnidium monnieri (TCFC) possess evident biological activities based on their coumarin compounds. The purpose of this manuscript is to investigate the effects of topical use of TCFC on immune response, inflammation, and skin barrier function in rats with 2,4-dinitrochlorobenzene (DNCB)-induced AD. Results indicated that the skin lesion scores of rats were obviously reduced after the management of TCFC, and the spleen and thymus indices also were markedly repressed. TCFC significantly inhibited the overproduction of TNF-α, interferon-γ, interleukin (IL)-4, IL-13, thymic stromal lymphopoietin, and immunoglobulin E; the epidermal thickness and number of mast cells were notably decreased. The western blot experiment was conducted to determine the effects of TCFC on the mitogen-activated protein kinases signaling pathway. Results indicated that phosphorylation of extracellular signal-regulated kinases, p38, and c-Jun amino-terminal kinases was significantly blocked by TCFC. In addition, TCFC could upregulate the expression of filaggrin in dorsal skin, which means that TCFC showed a protective effect on skin barrier disruption. Furthermore, TCFC downregulated the levels of IL-1β, IL-4, IL-31, and TSLP mRNA and upregulated the expression of filaggrin mRNA in the dorsal skin of rats. Our research demonstrated the ameliorative effects of TCFC on AD-like rats by inhibiting immune response and inflammation and recovering skin barrier function.

Airway relaxation mechanisms and structural basis of osthole for improving lung function in asthma

Overuse of β2-adrenoceptor agonist bronchodilators evokes receptor desensitization, decreased efficacy, and an increased risk of death in asthma patients. Bronchodilators that do not target β2-adrenoceptors represent a critical unmet need for asthma management. Here, we characterize the utility of osthole, a coumarin derived from a traditional Chinese medicine, in preclinical models of asthma. In mouse precision-cut lung slices, osthole relaxed preconstricted airways, irrespective of β2-adrenoceptor desensitization. Osthole administered in murine asthma models attenuated airway hyperresponsiveness, a hallmark of asthma. Osthole inhibited phosphodiesterase 4D (PDE4D) activity to amplify autocrine prostaglandin E₂ signaling in airway smooth muscle cells that eventually triggered cAMP/PKA-dependent relaxation of airways. The crystal structure of the PDE4D complexed with osthole revealed that osthole bound to the catalytic site to prevent cAMP binding and hydrolysis. Together, our studies elucidate a specific molecular target and mechanism by which osthole induces airway relaxation. Identification of osthole binding sites on PDE4D will guide further development of bronchodilators that are not subject to tachyphylaxis and would thus avoid β2-adrenoceptor agonist resistance.

Airborne Bacteria Enriched PM2.5 Enhances the Inflammation in an Allergic Adolescent Mouse Model Induced by Ovalbumin

Air pollution events frequently occur in China during the winter. Most investigations of pollution studies have focused on the physical and chemical properties of PM2.5. Many of these studies have indicated that PM2.5 exacerbates asthma or eosinophil inflammation. However, few studies have evaluated the relationship between bacterial loads in PM2.5, and especially pathogenic bacteria and childhood asthma. Airborne PM2.5 samples from heavily polluted air were collected in Hangzhou, China between December 2014 and January 2015. PM2.5 and ovalbumin (OVA) were intratracheally administered twice in 4-week intervals to induce the allergic pulmonary inflammation in adolescent C57/BL6 mice. PM2.5 exposure caused neutrophilic alveolitis and bronchitis. In the presence of OVA, the levels of the Th2 cytokines IL-4, IL-12, and IL-17 were significantly increased in bronchoalveolar lavage fluids (BALF) after PM2.5 exposure, while eosinophil infiltration and mucin secretion were also induced. In addition to adjuvant effects on OVA-induced allergic inflammation, PM2.5 exposure also led to the maturation of dendritic cells. These results suggest that PM2.5 exposure may aggravate lung eosinophilia and that PM2.5-bound microbial can exacerbate allergic and inflammatory lung diseases.

Osthole attenuates mouse atopic dermatitis by inhibiting thymic stromal lymphopoietin production from keratinocytes

Atopic dermatitis is one of the most common skin diseases. Dysregulation of immune system and chronic inflammation were believed to be associated with atopic dermatitis. Osthole was reported to play important roles in antitumor and anti-inflammation. However, whether osthole has effects on atopic dermatitis remains unclear. In this present study, we explored the biological role of osthole in atopic dermatitis and the molecular mechanism. Atopic dermatitis was induced by 2,4-dinitrochlorobenzene. Pathological damage of ear was detected by H&E staining. IgE level in serum or thymic stromal lymphopoietin (TSLP) level in supernatant was detected by ELISA. Interleukin (IL)-4 expression and IL-13 expression in CD4⁺ T cells were detected using flow cytometry. The expression levels of mRNA or protein levels were detected by RT-PCR or Western blot. Osthole attenuated atopic dermatitis development in mouse model. Osthole inhibits Th2 cell response, but have on influence on Th1 or Th17 cell response in the skin. In mouse model, osthole treatment significantly inhibited atopic dermatitis via directly inhibiting TLSP expression levels in keratinocytes. Osthole treatment alleviates atopic dermatitis through directly down-regulating TSLP production from keratinocytes. Osthole may serve as a potential choice for atopic dermatitis treatment in clinic.

Repeated Herbal Acupoint Sticking Relieved the Recurrence of Allergic Asthma by Regulating the Th1/Th2 Cell Balance in the Peripheral Blood

Allergic asthma is an inflammatory disease involving the Th1/Th2 cell imbalance in the peripheral blood. Repeated herbal acupoint sticking (RHAS) has been used for hundreds of years in China to relieve the recurrence of allergic asthma, and it is still practiced today. Thus, we explored the effect on allergic asthma relapse and the underlying immunoregulatory mechanism in this study. Here, we enrolled 50 allergic asthma participants, and 38 of them completed the treatment and follow-up (the allergic asthma group). In addition, 13 healthy participants (the control group) were enrolled. The recurrence number of allergic asthma participants and asthma control test (ACT) were used to evaluate the effect of treatment on relieving allergic asthma recurrence. Flow cytometry was performed to analyze the levels of Th1 and Th2 cells in the peripheral blood. The serum levels of IgE, IFN-γ, and IL-4 were detected by ELISA. (1) In the allergic asthma group, compared to before the first treatment, the recurrence number of allergic asthma participants decreased and the ACT score increased at end of the last treatment, 18 and 30 weeks of the trial (P < 0.05). At 18 and 30 weeks of the trial, the recurrence number of allergic asthma participants was less and the ACT score was higher than the ones from the same period last year in the allergic asthma group (P < 0.05). Compared to before the first treatment, the percentage of Th1 cell did not change significantly, the percentage of Th2 cell decreased, and the Th1/Th2 cell ratio increased in the allergic asthma group by the end of the last treatment (P < 0.05). Meanwhile, the release of IgE and IL-4 reduced (P < 0.05), and the release of IFN-γ did not significantly change in the allergic asthma group. (2) Compared with the control group, the serum levels of IgE and IL-4 and the percentage of Th2 cell were higher, and the Th1/Th2 cell ratio was lower in the allergic asthma group (P < 0.05). There was no significant difference between Th1 cell and IFN-γ before the first treatment. (3) Compared with the control group, the IgE levels and the percentage of Th2 cell were higher in the allergic asthma group (P < 0.01). Simultaneously, there was no significant difference between Th1 cell, the Th1/Th2 cell ratio, and the serum levels of IFN-γ and IL-4 by the end of the last treatment. The data suggested that RHAS reduced the amount of Th2 cell and elevated the Th1/Th2 cell ratio, thereby alleviating the inflammatory responses in the allergic asthma participants.

Osthole, a Natural Plant Derivative Inhibits MRGPRX2 Induced Mast Cell Responses

Mast cells are tissue-resident innate immune cells known for their prominent role in mediating allergic reactions. MAS-related G-protein coupled receptor-X2 (MRGPRX2) is a promiscuous G-protein coupled receptor (GPCR) expressed on mast cells that is activated by several ligands that share cationic and amphipathic properties. Interestingly, MRGPRX2 ligands include certain FDA-approved drugs, antimicrobial peptides, and neuropeptides. Consequently, this receptor has been implicated in causing mast cell-dependent pseudo-allergic reactions to these drugs and chronic inflammation associated with asthma, urticaria and rosacea in humans. In the current study we examined the role of osthole, a natural plant coumarin, in regulating mast cell responses when activated by the MRGPRX2 ligands, including compound 48/80, the neuropeptide substance P, and the cathelicidin LL-37. We demonstrate that osthole attenuates both the early (Ca2+ mobilization and degranulation) and delayed events (chemokine/cytokine production) of mast cell activation via MRGPRX2 in vitro. Osthole also inhibits MrgprB2- (mouse ortholog of human MRGPRX2) dependent inflammation in in vivo mouse models of pseudo-allergy. Molecular docking analysis suggests that osthole does not compete with the MRGPRX2 ligands for interaction with the receptor, but rather regulates MRGPRX2 activation via allosteric modifications. Furthermore, flow cytometry and confocal microscopy experiments reveal that osthole reduces both surface and intracellular expression levels of MRGPRX2 in mast cells. Collectively, our data demonstrate that osthole inhibits MRGPRX2/MrgprB2-induced mast cell responses and provides a rationale for the use of this natural compound as a safer alternative treatment for pseudo-allergic reactions in humans.

Osthole: A Traditional Chinese Medicine for Ocular Anti-Angiogenic Therapy

PURPOSE

Osthole is an agent isolated from Cnidium monnieri (L.) Cusson and has been used to treat several disorders. Corneal neovascularization is a sight-threatening condition associated with several inflammatory or infectious ocular disorders. In this study, we investigated the anti-angiogenic effects of osthole on corneal neovascularization and the underlying mechanism.

METHODS

MTT assay, HE staining, and calcein-AM/propidium iodide staining was conducted to detect the toxicity of osthole in vitro and in vivo. Corneal neovascularization of ICR mice was induced by alkali burn and observed by a slit lamp microscopy on day 7 after alkali injury. EdU assay, Ki67 immunofluorescence assay, Transwell migration assay, and Matrigel assay were conducted to investigate the role of osthole in endothelial angiogenic effects in vitro. Western blots were conducted to investigate the anti-angiogenic mechanism of osthole in corneal neovascularization.

RESULTS

Administration of osthole ranging from 0.05 to 25 µM had no detectable cytotoxicity or tissue toxicity in vivo and in vitro. Topical administration of osthole inhibited corneal neovascularization induced by alkali burn. Osthole decreased the proliferation, migration, and tube-formation of endothelial cells induced by VEGF. Osthole inhibited endothelial angiogenic functions through blocking the phosphorylation of ERK1/2, JNK, and p38.

CONCLUSION

Our study provides evidence that osthole is a promising drug for the treatment of corneal neovascularization.

Osthole inhibits the progression of human gallbladder cancer cells through JAK/STAT3 signal pathway both in vitro and in vivo

Osthole is an antitumor compound, which effect on Gallbladder cancer (GBC) has been not elucidated. This study focused on its anti-GBC effect and mechanism both in vitro and in vivo. The antiproliferation effect on cell lines NOZ and SGC-996 were measured by cell counting kit-8 (CCK-8) and colony formation assay. The effects on cell apoptosis and cell cycle were investigated by flow cytometry assay. The migration effect was checked by transwell assay and the expressions of proteins were examined by Western Blots. Also, we did an in-vivo experiment by intraperitoneal injection of osthole in nude mice. The results showed that cell proliferation and viability were inhibited in a dose- and time-dependent manner. The similar phenomenon was also found in vivo. Flow cytometric assay confirmed that osthole inhibited cells proliferation via inducing apoptosis and G2/M arrest. Transwell assay indicated that osthole inhibited the migration in a dose-dependent manner. Expression of key proteins related with apoptosis and cell cycle were testified after osthole treatment. Also, we found the key proteins involved in the JAK/STAT3 signal way decreased after osthole treatment. This study suggested that osthole can inhibit the progression of human GBC cell lines, thus maybe a potential drug for GBC treatment.

Wenshen decoction suppresses inflammation in IL-33-induced asthma murine model via inhibiting ILC2 activation

Background

Wenshen decoction, consisting of Epimedium brevicornu Maxim, Morinda officinalis How and Cnidium monnieri (L.) Cusson, has favorable efficacy in the treatment of asthma in China.

Methods

The present study investigated the potential immunomodulatory mechanism underlying the therapeutic effects of Wenshen decoction on mouse asthma.

Results

Oral Wenshen decoction could ameliorate the production of IL-4, IL-5, IL-13 in the bronchoalveolar lavage fluid (BALF), reduce serum IgE, and improve the airway hyperresponsiveness (AHR) and airway inflammation in the BALB/c mice after intranasal treatment with recombinant IL-33. Moreover, Wenshen decoction reduced ILC2 and RORα mRNA expression, decreased the mRNA expression of ICOS and ST2 in the lung, but significantly increased the production of IFN-γ.

Conclusions

Our study indicates that Wenshen decoction may inhibit the activation of ILC2 through the IL-33/ST2/ICOS pathway to further suppress airway inflammation and AHR in the asthmatic mice, and the increased IFN-γ might be related to the effects of Wenshen decoction on ILC2.

Clinical and Basic Studies on Therapeutic Efficacy of Herbal Medicines against Mycobacterial Infections

The high incidence of tuberculosis (TB) in developing countries, the resurgence of TB in industrialized countries, and the worldwide increase in the prevalence of Mycobacterium avium complex infections are important global health concerns. However, the development of novel antimycobacterial drugs is currently making very slow progress. Therefore, it is considered that devising improved administration protocols for clinical treatment against intractable mycobacteriosis using existing chemotherapeutics is more practical than awaiting the development of new antimycobacterial drugs. The regulation of host immune responses using immunoadjunctive agents may increase the efficacy of antimicrobial treatment against mycobacteriosis. In particular, the mild and long-term up-regulation of host immune reactions against mycobacterial pathogens using herbal medicines may be beneficial for such immunoadjunctive therapy. This review focuses on the current status regarding basic and clinical studies on protocols using herbal medicines, including medicinal plants, useful for the clinical treatment of intractable mycobacterial infections.

TLR4 antagonist ameliorates combined allergic rhinitis and asthma syndrome (CARAS) by reducing inflammatory monocytes infiltration in mice model

The present study aims to investigate the effects of toll-like receptor 4 (TLR4) antagonist in an ovalbumin (OVA)-induced mouse model of combined allergic rhinitis and asthma syndrome (CARAS). An OVA-induced mouse model of CARAS was established and TLR4 antagonist, TAK-242, was administrated intranasally or intraperitoneally. The number of sneezing and nasal rubbing was counted. The frequency of different cell types in the bronchoalveolar lavage fluid (BALF) and nasal lavage fluid (NLF) was analyzed using flow cytometry. Expressions of protein in nasal mucosa and lungs were determined using western blotting. Levels of interleukin (IL)-4, IL-5, and IL-13 were determined using Enzyme-linked Immunosorbent Assay (ELISA). Histological scores were applied for the assessment of lung injury. Treatment of TAK-242 downregulated CCL2 expression and reduced monocyte infiltration in nasal mucosa and lung tissues. Additionally, treatment of TAK-242 ameliorated upper airway symptoms including the sneezing and nasal rubbing by the regulation of cytokines including IL-4, IL-5, and IL-13. Furthermore, treatment of TAK-242 ameliorated lower airway symptoms including decreasing the frequency of CD45⁺SiglecF⁺CD11b⁺CD11c^- eosinophils in BALF and IL13⁺ Th2 cells in the lungs. In conclusion, treatment of TAK-242 ameliorated CARAS-related lung injury by inhibiting lymphocyte infiltration, reducing monocytes infiltration, as well as regulating the frequency of eosinophils and Th2 cells.

The amino acid sensor general control nonderepressible 2 (GCN2) controls TH9 cells and allergic airway inflammation

BACKGROUND

T_H9 cells have emerged as important mediators of allergic airway inflammation. There is evidence that general control nonderepressible 2 (GCN2) affects the immune response under some stress conditions. However, whether GCN2 regulates CD4⁺ T-cell differentiation during allergic inflammation remains unknown.

OBJECTIVE

We sought to clarify the regulatory roles of GCN2 in CD4⁺ T-cell subset differentiation and its significance in patients with allergic airway inflammation.

METHODS

The effects of GCN2 in differentiation of T_H cell subsets were detected by using the in vitro induction system. GCN2 knockout mice, ovalbumin-induced allergic airway inflammation, and adoptive transfer mouse models were used to determine the significance of GCN2 in T_H9 differentiation and allergic airway inflammation in vivo. RNA sequencing, real-time PCR, Western blotting, and other molecular approaches were used to identify the molecular mechanisms relevant to regulation of GCN2 in T_H9 cell differentiation.

RESULTS

GCN2 deficiency significantly inhibited differentiation of T_H9 cells but not T_H1, T_H2, and regulatory T cells. GCN2 knockout mice and recombination-activating gene 2 knockout (Rag2KO) mice that received adoptively transferred GCN2-deficient CD4⁺ T cells exhibited reduced T_H9 differentiation and less severe allergic airway inflammation. Furthermore, the isolated GCN2-deficient T_H9 cells also mediated less severe allergic airway inflammation on adoptive transfer. Mechanistically, GCN2 deficiency inhibits T_H9 cell differentiation through a hypoxia-inducible factor 1α-dependent glycolytic pathway.

CONCLUSION

Our results reveal a novel role of GCN2 in T_H9 cell differentiation. Our findings indicate that new strategies to inhibit GCN2 activity might provide novel approaches to attenuate allergic airway inflammation.

Osthole promotes the suppressive effects of cisplatin on NRF2 expression to prevent drug-resistant cervical cancer progression

Cervical cancer is one of the most commonly diagnosed lethal malignancies among gynecological malignant tumors worldwide. Chemo-resistance is one of the key causal factors in cervical cancer death. Osthole (OST), a natural compound, exhibits various pharmacological activities, including anti-tumor effects. However, its involvement in the chemoresistance of human cervical cancer has not been reported. In the study, we aimed to clarify the role of OST in regulating the chemoresistance of human cervical cancer. The results indicated that cisplatin (CDDP) combined with OST markedly reduced the cell proliferation and induced cervical cancer cells undergoing apoptosis when compared to CDDP alone treatment. In CDDP-resistant cervical cancer cells, OST significantly decreased nuclear factor, erythroid 2 like 2 (NRF2), heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1) and glutamate-cysteine ligase catalytic subunit (GCLC) expression levels from mRNA or protein levels. Additionally, through combination with CDDP, OST dose- and time-dependently reduced NRF2 expression in CDDP-resistant cervical cancer cells. Moreover, we found that CDDP co-treated with OST significantly blocked phosphatidylinositol-3 kinase (PI3K)/AKT signaling pathway. Importantly, CDDP combined with LY294002, inhibitor of phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT) signaling, markedly decreased the expression of NRF2, HO-1, NQO1 and GCLC in drug-resistant cervical cancer cells. The in vivo study also suggested that OST in combination obviously reduced tumor growth in comparison to the CDDP alone group. Taken together, these findings indicated that OST could be used as a potential sensitizer to reverse chemoresistance of cisplatin-resistant cervical cancer to cisplatin through repressing NRF2 expression partly associated with PI3K/AKT blockage.

Osthole Ameliorates Renal Fibrosis in Mice by Suppressing Fibroblast Activation and Epithelial-Mesenchymal Transition

Renal fibrosis is a common pathway of virtually all progressive kidney diseases. Osthole (OST, 7-Methoxy-8-(3-methylbut-2-enyl)-2-chromenone), a derivative of coumarin mainly found in plants of the Apiaceae family, has shown inhibitory effects on inflammation, oxidative stress, fibrosis and tumor progression. The present study investigated whether OST mediates its effect via suppressing fibroblast activation and epithelial-mesenchymal transition (EMT) in unilateral ureteral obstruction (UUO)-induced renal fibrosis in mice. Herein, we found that OST inhibited fibroblast activation in a dose-dependent manner by inhibiting the transforming growth factor-β1 (TGFβ1)-Smad pathway. OST also blocked fibroblast proliferation by reducing DNA synthesis and downregulating the expressions of proliferation- and cell cycle-related proteins including proliferating cell nuclear antigen (PCNA), CyclinD1 and p21 Waf1/Cip1. Meanwhile, in the murine model of renal interstitial fibrosis induced by UUO, myofibroblast activation with increased expression of α-smooth muscle actin (α-SMA) and proliferation were attenuated by OST treatment. Additionally, we provided in vivo evidence suggesting that OST repressed EMT with preserved E-cadherin and reduced Vimentin expression in obstructed kidney. UUO injury-induced upregulation of EMT-related transcription factors, Snail family transcriptional repressor-1(Snail 1) and Twist family basic helix-loop-helix (BHLH) transcription factor (Twist) as well as elevated G2/M arrest of tubular epithelial cell, were rescued by OST treatment. Further, OST treatment reversed aberrant expression of TGFβ1-Smad signaling pathway, increased level of proinflammatory cytokines and NF-kappaB (NF-κB) activation in kidneys with obstructive nephropathy. Taken together, these findings suggest that OST hinder renal fibrosis in UUO mouse mainly through inhibition of fibroblast activation and EMT.

Activation of TLR Signaling in Sensitization-Recruited Inflammatory Monocytes Attenuates OVA-Induced Allergic Asthma

The activation of Toll-like receptor (TLR) signaling is widely reported to be involved in preventing the development of allergic asthma. However, the mechanism of the protective function of TLR signaling remains limited. Here, we studied the mouse model of ovalbumin (OVA)-induced allergic asthma and found that deficiency of TLR signaling or activating TLR signaling with agonist would aggravate or attenuate OVA-induced allergic asthma, respectively, and TLR signaling-mediated protective effect mainly affected the sensitization phase. After OVA/alum sensitization, neutrophils and inflammatory monocytes were recruited into peritoneal cavity and up-regulated TLRs expression. However, adoptive transfer of inflammatory monocytes but not peritoneal macrophages or neutrophils induced allergic symptoms in recipient mice after OVA challenge even without OVA/alum sensitization, and treating the inflammatory monocytes with TLR agonist in vitro before transfer could abolish this effect, indicating that recruited inflammatory monocytes played a determinant role in OVA-induced allergic asthma, and activation of TLR signaling in them could attenuate allergic symptoms. Finally, we found that activation of TLR signaling could increase the expression of T-helper (Th) 1-associated cytokines in inflammatory monocytes. Our results suggest that activation of TLR signaling in sensitization-recruited inflammatory monocytes attenuates OVA-induced allergic asthma by promoting the expression of Th1-associated cytokines.

Emodin alleviates alternatively activated macrophage and asthmatic airway inflammation in a murine asthma model

Alternatively activated macrophages (AAMs) are not only associated with asthma but also lead to asthmatic airway inflammation and remodeling. Inhibition of AAMs is an alternative therapeutic strategy for treating asthma. In this study we investigated whether emodin (1,3,8-trihydroxy-6-methylanthraquinone), isolated from the rhizome of Rheum palmatum, alleviated asthmatic airway inflammation and reduced AAM polarization in a murine asthma model. Mice were sensitized with a triple allergen mix containing dust mite, ragweed and aspergillus (DRA). In mice with DRA-induced asthma, asthmatic inflammation was significantly enhanced. Intraperitoneal injection of emodin (20 mg·kg^-1·d^-1, ip) 1 h prior to DRA challenge on days 12-14 significantly decreased pulmonary eosinophil and lymphocyte infiltration, mucus secretion and serum IgE production, as well as IL-4 and IL-5 production in bronchoalveolar lavage fluid. In response to emodin treatment, activated markers of AAM Ym-1, Fizz-1 and arginase-1 in the lung tissues were remarkably decreased. In mouse bone marrow-derived macrophages (BMDMs) in vitro, emodin (2-50 μmol/L) dose-dependently inhibited IL-4-induced AAM polarization and STAT6 phosphorylation. Collectively, our results suggest that emodin effectively ameliorates asthmatic airway inflammation and AAM polarization, and it may therefore become a potential agent for the treatment of asthma.

Osthole inhibits pancreatic cancer progression by directly exerting negative effects on cancer cells and attenuating tumor-infiltrating M2 macrophages

Pancreatic cancer has remained a major cause of cancer-related deaths. A hallmark of pancreatic cancer is extensive stromal reactions, resulting in a unique tumor microenvironment, especially the involvement of macrophages. These tumor-educated cells limit the efficacy of chemotherapy. Therefore, it is necessary to identify an effective treatment strategy. In this study, we aimed to explore the anti-tumor and immunomodulatory effects of osthole on pancreatic cancer. We found that osthole suppressed Panc 02 cell migration and proliferation and induced apoptosis as shown in vitro. Osthole also attenuated the development of pancreatic cancer in mice by inhibiting tumor-infiltrating M2 macrophages in our study. Additionally, osthole inhibited the polarization of primary bone marrow cells into M2 macrophages and inhibited the expression of MRC1, CCL22 and TGF-β in the M2 polarization process in vitro. Detection of the related signaling pathways revealed that osthole exerted immunomodulatory effects on M2 macrophages by down-regulating p-STAT6 and the p-ERK1/2-C/EBP β axis. These results indicated that osthole has effective anti-tumor and immunomodulatory effects on pancreatic cancer.