Essential role of phosphoinositide 3-kinase gamma in eosinophil chemotaxis within acute pulmonary inflammation

Integration of metabolomics and transcriptomics reveals the therapeutic mechanism underlying Chelidonium majus L. in the treatment of allergic asthma

BACKGROUND

Chelidonium majus is a well-known traditional Chinese medicine, and has been reported of the effect in relieving cough and asthma. However, the mechanism of action is still unknown.

METHODS

Asthmatic SD rats were first sensitized and established through ovalbumin (OVA) motivation. Subsequently, Hematoxylin and eosin (H&E) staining, Masson's trichrome (Masson) staining, Periodic acid-Schiff (PAS) staining and inflammatory cytokines assay of interleukin (IL)-4, IL-6, IL-17 were implemented to evaluate the protective effects of Chelidonium majus on asthma. Then, the effects of Chelidonium majus and their molecular mechanisms of action on asthma were detected based on the integration of transcriptomics and metabolomics analyses.

RESULTS

After administration with Chelidonium majus, the histological injuries of inflammation, collagen deposition and mucus secretion in lungs were attenuated and the serum inflammatory cytokines perturbations were also converted. Furthermore, integrated analysis revealed that after Chelidonium majus treatment, 7 different expression genes (DEGs) (Alox15, P4ha1, Pla2g16, Pde3a, Nme1, Entpd8 and Adcy9) and 9 metabolic biomarkers (ADP, Xanthosine, Hypoxanthine, Inosine, prostaglandin E2 (PGE2), prostaglandin F2a (PGF2a), phosphatidylserine, Creatine and LysoPC (10:0)) were discovered to be connected with the enrichment metabolic pathways, including Purine metabolism, Arachidonic acid metabolism, Arginine and proline metabolism and Glycerophospholipid metabolism. The obtained metabolic biomarkers and DEGs were mainly related to energy metabolism and inflammation, and may be potential therapeutic targets.

CONCLUSION

Chelidonium majus relieved OVA-induced asthma in rats by regulating the Alox15, P4ha1, Pla2g16, Pde3a, Nme1, Entpd8 and Adcy9 genes expression to restore the disorders in energy metabolism and inflammation.

Discovery of AZD8154, a Dual PI3Kγδ Inhibitor for the Treatment of Asthma

Starting from our previously described PI3Kγ inhibitors, we describe the exploration of structure-activity relationships that led to the discovery of highly potent dual PI3Kγδ inhibitors. We explored changes in two positions of the molecules, including macrocyclization, but ultimately identified a simpler series with the desired potency profile that had suitable physicochemical properties for inhalation. We were able to demonstrate efficacy in a rat ovalbumin challenge model of allergic asthma and in cells derived from asthmatic patients. The optimized compound, AZD8154, has a long duration of action in the lung and low systemic exposure coupled with high selectivity against off-targets.

Distinct roles of PI3Kδ and PI3Kγ in a toluene diisocyanate-induced murine asthma model

TDI-induced asthma is characterized by neutrophil-dominated airway inflammation and often associated with poor responsiveness to steroid treatment. Both PI3Kδ and PI3Kγ have been demonstrated to play important proinflammatory roles in ovalbumin-induced asthma. We've already reported that blocking pan PI3K effectively attenuated TDI-induced allergic airway inflammation. Yet the specific functions of PI3Kδ and PI3Kγ in TDI-induced asthma are still unclear. Male BALB/c mice were first dermally sensitized and then challenged with TDI to generate an asthma model. Sellective inhibitors of PI3Kδ (IC-87114, AMG319) and PI3Kγ (AS252424, AS605240) were respectively given to the mice after each airway challenge. Treatment with IC-87114 or AMG319 after TDI exposure led to significantly decreased airway hyperresponsiveness (AHR), less neutrophil and eosinophil accumulation, attenuated airway smooth muscle (ASM) thickening, less M1 and M2 macrophages in lung, as well as lower levels of IL-4, IL-5, IL-6 and IL-18 in bronchoalveolar lavage fluid (BALF) and recovered IL-10 production. While mice treated with AS252424 or AS605240 had increased AHR, more severe ASM thickening, larger numbers of neutrophils and eosinophils, more M1 but less M2 macrophages, and higher BALF levels of IL-4, IL-5, IL-6, IL-10, IL-12, IL-18 when compared with those treated with vehicle. These data revealed that pharmacological inhibition of PI3Kδ attenuates TDI-induced airway inflammation while PI3Kγ inhibition exacerbates TDI-induced asthma, indicating distinct biological functions of PI3Kδ and PI3Kγ in TDI-induced asthma.

Disease-related mutations in PI3Kγ disrupt regulatory C-terminal dynamics and reveal a path to selective inhibitors

Class I Phosphoinositide 3-kinases (PI3Ks) are master regulators of cellular functions, with the class IB PI3K catalytic subunit (p110γ) playing key roles in immune signalling. p110γ is a key factor in inflammatory diseases and has been identified as a therapeutic target for cancers due to its immunomodulatory role. Using a combined biochemical/biophysical approach, we have revealed insight into regulation of kinase activity, specifically defining how immunodeficiency and oncogenic mutations of R1021 in the C-terminus can inactivate or activate enzyme activity. Screening of inhibitors using HDX-MS revealed that activation loop-binding inhibitors induce allosteric conformational changes that mimic those in the R1021C mutant. Structural analysis of advanced PI3K inhibitors in clinical development revealed novel binding pockets that can be exploited for further therapeutic development. Overall, this work provides unique insights into regulatory mechanisms that control PI3Kγ kinase activity and shows a framework for the design of PI3K isoform and mutant selective inhibitors.

PI3Kγ Regulatory Protein p84 Determines Mast Cell Sensitivity to Ras Inhibition-Moving Towards Cell Specific PI3K Targeting?

Mast cells are the major effector cells in immunoglobulin E (IgE)-mediated allergy. The high affinity IgE receptor FcεRI, as well as G protein-coupled receptors (GPCRs) on the mast cell surface signals to phosphoinositide 3-kinase γ (PI3Kγ) to initiate degranulation, cytokine release, and chemotaxis. PI3Kγ is therefore considered as a target for treatment of allergic disorders. However, leukocyte PI3Kγ is key to many functions in innate and adaptive immunity, and attenuation of host defense mechanisms is an expected adverse effect that complicates treatment of chronic illnesses. PI3Kγ operates as a p110γ/p84 or p110γ/p101 complex, where p110γ/p84 requires Ras activation. Here we investigated if modulation of Ras-isoprenylation could target PI3Kγ activity to attenuate PI3Kγ-dependent mast cell responses without impairment of macrophage functions. In murine bone marrow-derived mast cells, GPCR stimulation triggers activation of N-Ras and H-Ras isoforms, which is followed by the phosphorylation of protein kinase B (PKB/Akt) relayed through PI3Kγ. Although K-Ras is normally not activated in Ras wild-type cells, it is able to compensate for genetically deleted N- and H-Ras isoforms. Inhibition of Ras isoprenylation with farnesyltransferase inhibitor FTI-277 leads to a significant reduction of mast cell degranulation, cytokine production, and migration. Complementation experiments expressing PI3Kγ adaptor proteins p84 or p101 demonstrated a differential sensitivity towards Ras-inhibition depending on PI3Kγ complex composition. Mast cell responses are exclusively p84-dependent and were effectively controlled by FTI-277. Similar results were obtained when GTP-Ras was inactivated by overexpression of the GAP-domain of Neurofibromin-1 (NF-1). Unlike mast cells, macrophages express p84 and p101 but are p101-dominated and thus remain functional under treatment with FTI-277. Our work demonstrates that p101 and p84 have distinct physiological roles, and that Ras dependence of PI3Kγ signaling differs between cell types. FTI-277 reduces GPCR-activated PI3Kγ  responses in p84-expressing but not p101-containing bone marrow derived cells. However, prenylation inhibitors have pleiotropic effects beyond Ras and non-tolerable side-effects that disfavor further clinical validation. Statins are, however, clinically well-established drugs that have previously been proposed to block mast cell degranulation by interference with protein prenylation. We show here that Simvastatin inhibits mast cell degranulation, but that this does not occur via Ras-PI3Kγ pathway alterations.

Human PI3Kγ deficiency and its microbiota-dependent mouse model reveal immunodeficiency and tissue immunopathology

Phosphatidylinositol 3-kinase-gamma (PI3Kγ) is highly expressed in leukocytes and is an attractive drug target for immune modulation. Different experimental systems have led to conflicting conclusions regarding inflammatory and anti-inflammatory functions of PI3Kγ. Here, we report a human patient with bi-allelic, loss-of-function mutations in PIK3CG resulting in absence of the p110γ catalytic subunit of PI3Kγ. She has a history of childhood-onset antibody defects, cytopenias, and T lymphocytic pneumonitis and colitis, with reduced peripheral blood memory B, memory CD8+ T, and regulatory T cells and increased CXCR3+ tissue-homing CD4 T cells. PI3Kγ-deficient macrophages and monocytes produce elevated inflammatory IL-12 and IL-23 in a GSK3α/β-dependent manner upon TLR stimulation. Pik3cg-deficient mice recapitulate major features of human disease after exposure to natural microbiota through co-housing with pet-store mice. Together, our results emphasize the physiological importance of PI3Kγ in restraining inflammation and promoting appropriate adaptive immune responses in both humans and mice.

For Better or Worse: The Potential for Dose Limiting the On-Target Toxicity of PI 3-Kinase Inhibitors

The hyper-activation of the phosphoinositide (PI) 3-kinase signaling pathway is a hallmark of many cancers and overgrowth syndromes, and as a result, there has been intense interest in the development of drugs that target the various isoforms of PI 3-kinase. Given the key role PI 3-kinases play in many normal cell functions, there is significant potential for the disruption of essential cellular functions by PI 3-kinase inhibitors in normal tissues; so-called on-target drug toxicity. It is, therefore, no surprise that progress within the clinical development of PI 3-kinase inhibitors as single-agent anti-cancer therapies has been slowed by the difficulty of identifying a therapeutic window. The aim of this review is to place the cellular, tissue and whole-body effects of PI 3-kinase inhibition in the context of understanding the potential for dose limiting on-target toxicities and to introduce possible strategies to overcome these.

Novel benzofuran derivative DK-1014 attenuates lung inflammation via blocking of MAPK/AP-1 and AKT/mTOR signaling in vitro and in vivo

Benzofuran derivatives have wide range of biological activities as anti-oxidant, anti-inflammatory and anticonvulsant agent. In this study, we investigated whether the novel benzofuran derivative, DK-1014 has the anti-inflammatory effects on macrophage and lung epithelial cells and anti-asthmatic effects on ovalbumin-treated mice. A series of 2-arylbenzofuran analogues were synthesized and evaluated for NO and interleukin-6 (IL-6) inhibition in LPS-stimulated Raw264.7 cells. Of these analogues, compounds 8, 22a, 22d, and 22 f (DK-1014) exhibited notable inhibitory activity with respect to IL-6 and NO production. In particular, compound DK-1014 strongly reduced IL-6, IL-8, and MMP-9 mRNA expression and IL-6, IL-8, and MCP-1 production in phorbol myristate acetate stimulated A549 cells, reduced MAPKs phosphorylation and c-fos translocation, and attenuated AKT, p70S6K and GSK phosphorylation. In vivo experiments were also performed on ovalbumin-sensitized and challenged BALB/c mice. DK-1014 reduced the airway hyperresponsiveness, inflammatory cell counts and cytokine levels (IL-4, 5, 13) in bronchial alveolar lavage fluid (BALF) and immunoglobulin E in serum, and attenuated inflammatory cell infiltration and mucus hypersecretion in lung tissue. These findings indicate that DK-1014 can protect against allergic airway inflammation through the AP-1 and AKT/mTOR pathways and could be useful source for the development of a therapeutic agent for asthma.

Advanced Role of Neutrophils in Common Respiratory Diseases

Respiratory diseases, always being a threat towards the health of people all over the world, are most tightly associated with immune system. Neutrophils serve as an important component of immune defense barrier linking innate and adaptive immunity. They participate in the clearance of exogenous pathogens and endogenous cell debris and play an essential role in the pathogenesis of many respiratory diseases. However, the pathological mechanism of neutrophils remains complex and obscure. The traditional roles of neutrophils in severe asthma, chronic obstructive pulmonary diseases (COPD), pneumonia, lung cancer, pulmonary fibrosis, bronchitis, and bronchiolitis had already been reviewed. With the development of scientific research, the involvement of neutrophils in respiratory diseases is being brought to light with emerging data on neutrophil subsets, trafficking, and cell death mechanism (e.g., NETosis, apoptosis) in diseases. We reviewed all these recent studies here to provide you with the latest advances about the role of neutrophils in respiratory diseases.

Comprehensive attenuation of IL-25-induced airway hyperresponsiveness, inflammation and remodelling by the PI3K inhibitor LY294002

BACKGROUND AND OBJECTIVE

Existing in vitro and in vivo studies suggest that both IL-25 and phosphoinositide 3-kinases (PI3Ks) exhibit broad effects on the functions of immune cells implicated in the pathogenesis of asthma. Whether the blockade of PI3K signalling directly inhibits the asthma relevant pathogenetic changes induced by IL-25 in an in vivo condition is still unclear. Using an established IL-25-induced murine model of asthma, we undertook a comprehensive evaluation of the effects of co-administered LY294002, a pharmacological pan-inhibitor of PI3K on IL-25-induced changes on this model, with particular regard to airway remodelling.

METHODS

BALB/c mice were serially intranasally challenged with IL-25 according to an established protocol to induce airway inflammation, hyperresponsiveness (AHR) and remodelling. In an additional subgroup LY294002 was administered intranasally. Lung function and airway cytokine and chemokine concentrations and cellular infiltration and remodelling changes assessed by histology and immunohistochemistry were measured at specific time points.

RESULTS

Intranasal administration of LY294002 significantly inhibited IL-25-induced AHR and recruitment of inflammatory cells into bronchoalveolar lavage fluid. LY294002 also attenuated IL-25-induced increased concentrations of cytokines and chemokines in lung tissue. Histological and immunohistochemical analysis showed that LY294002 also significantly inhibited IL-25-induced lung tissue eosinophilia, mucus production, collagen deposition, smooth muscle hypertrophy and angiogenesis.

CONCLUSION

The PI3K pan-inhibitor LY294002 attenuated not only IL-25-induced asthma-like AHR and airway inflammation but also remodelling in this model, suggesting that PI3K is a major downstream messenger for IL-25 and that targeting this pathway might reduce asthma symptoms in the short term and airway remodelling in the longer term.

Role of phosphoinositide-3 kinase signaling pathways in pathogenesis of acute pancreatitis

Acute pancreatitis (AP) as a common acute disease poses a great threat to people's health. According to statistics, about one-fifth of cases develop acute respiratory distress syndrome and multiple organ dysfunction, which result in high mortality. The early understanding of the pathogenesis of this disease is limited to an inflammatory response resulting in autodigestion, edema, hemorrhage and necrosis of pancreatic tissue after the abnormal activation of trypsin. In recent years, researchers have focused their research on the role of immune inflammatory response in the pathogenesis of AP. Here we discuss the relationship between the immune inflammation and PI3K signaling pathways in AP.

Kaempferol and inflammation: From chemistry to medicine

Inflammation is an important process of human healing response, wherein the tissues respond to injuries induced by many agents including pathogens. It is characterized by pain, redness and heat in the injured tissues. Chronic inflammation seems to be associated with different types of diseases such as arthritis, allergies, atherosclerosis, and even cancer. In recent years natural product based drugs are considered as the novel therapeutic strategy for prevention and treatment of inflammatory diseases. Among the different types of phyto-constituents present in natural products, flavonoids which occur in many vegetable foods and herbal medicines are considered as the most active constituent, which has the potency to ameliorate inflammation under both in vitro and in vivo conditions. Kaempferol is a natural flavonol present in different plant species, which has been described to possess potent anti-inflammatory properties. Despite the voluminous literature on the anti-inflammatory effects of kaempferol, only very limited review articles has been published on this topic. Hence the present review is aimed to provide a critical overview on the anti-inflammatory effects and the mechanisms of action of kaempferol, based on the current scientific literature. In addition, emphasis is also given on the chemistry, natural sources, bioavailability and toxicity of kaempferol.

Role of phosphoinositide 3-kinase in the pathogenesis of acute pancreatitis

A large body of experimental and clinical data supports the notion that inflammation in acute pancreatitis has a crucial role in the pathogenesis of local and systemic damage and is a major determinant of clinical severity. Thus, research has recently focused on molecules that can regulate the inflammatory processes, such as phosphoinositide 3-kinases (PI3Ks), a family of lipid and protein kinases involved in intracellular signal transduction. Studies using genetic ablation or pharmacologic inhibitors of different PI3K isoforms, in particular the class I PI3Kδ and PI3Kγ, have contributed to a greater understanding of the roles of these kinases in the modulation of inflammatory and immune responses. Recent data suggest that PI3Ks are also involved in the pathogenesis of acute pancreatitis. Activation of the PI3K signaling pathway, and in particular of the class IB PI3Kγ isoform, has a significant role in those events which are necessary for the initiation of acute pancreatic injury, namely calcium signaling alteration, trypsinogen activation, and nuclear factor-κB transcription. Moreover, PI3Kγ is instrumental in modulating acinar cell apoptosis, and regulating local neutrophil infiltration and systemic inflammatory responses during the course of experimental acute pancreatitis. The availability of PI3K inhibitors selective for specific isoforms may provide new valuable therapeutic strategies to improve the clinical course of this disease. This article presents a brief summary of PI3K structure and function, and highlights recent advances that implicate PI3Ks in the pathogenesis of acute pancreatitis.

Inhibition of PI3K signaling spurs new therapeutic opportunities in inflammatory/autoimmune diseases and hematological malignancies

The phosphoinositide 3-kinase/mammalian target of rapamycin/protein kinase B (PI3K/mTOR/Akt) signaling pathway is central to a plethora of cellular mechanisms in a wide variety of cells including leukocytes. Perturbation of this signaling cascade is implicated in inflammatory and autoimmune disorders as well as hematological malignancies. Proteins within the PI3K/mTOR/Akt pathway therefore represent attractive targets for therapeutic intervention. There has been a remarkable evolution of PI3K inhibitors in the past 20 years from the early chemical tool compounds to drugs that are showing promise as anticancer agents in clinical trials. The use of animal models and pharmacological tools has expanded our knowledge about the contribution of individual class I PI3K isoforms to immune cell function. In addition, class II and III PI3K isoforms are emerging as nonredundant regulators of immune cell signaling revealing potentially novel targets for disease treatment. Further complexity is added to the PI3K/mTOR/Akt pathway by a number of novel signaling inputs and feedback mechanisms. These can present either caveats or opportunities for novel drug targets. Here, we consider recent advances in 1) our understanding of the contribution of individual PI3K isoforms to immune cell function and their relevance to inflammatory/autoimmune diseases as well as lymphoma and 2) development of small molecules with which to inhibit the PI3K pathway. We also consider whether manipulating other proximal elements of the PI3K signaling cascade (such as class II and III PI3Ks or lipid phosphatases) are likely to be successful in fighting off different immune diseases.

PI3Kγ drives priming and survival of autoreactive CD4(+) T cells during experimental autoimmune encephalomyelitis

The class IB phosphoinositide 3-kinase gamma enzyme complex (PI3Kγ) functions in multiple signaling pathways involved in leukocyte activation and migration, making it an attractive target in complex human inflammatory diseases including MS. Here, using pik3cg^−/− mice and a selective PI3Kγ inhibitor, we show that PI3Kγ promotes development of experimental autoimmune encephalomyelitis (EAE). In pik3cg^−/− mice, EAE is markedly suppressed and fewer leukocytes including CD4⁺ and CD8⁺ T cells, granulocytes and mononuclear phagocytes infiltrate the CNS. CD4⁺ T cell priming in secondary lymphoid organs is reduced in pik3cg^−/− mice following immunisation. This is attributable to defects in DC migration concomitant with a failure of full T cell activation following TCR ligation in the absence of p110γ. Together, this results in suppressed autoreactive T cell responses in pik3cg^−/− mice, with more CD4⁺ T cells undergoing apoptosis and fewer cytokine-producing Th1 and Th17 cells in lymphoid organs and the CNS. When administered from onset of EAE, the orally active PI3Kγ inhibitor AS605240 caused inhibition and reversal of clinical disease, and demyelination and cellular pathology in the CNS was reduced. These results strongly suggest that inhibitors of PI3Kγ may be useful therapeutics for MS.

IL-4 engagement of the type I IL-4 receptor complex enhances mouse eosinophil migration to eotaxin-1 in vitro

Background

Previous work from our laboratory demonstrated that IL-4Rα expression on a myeloid cell type was responsible for enhancement of Th2-driven eosinophilic inflammation in a mouse model of allergic lung inflammation. Subsequently, we have shown that IL-4 signaling through type I IL-4 receptors on monocytes/macrophages strongly induced activation of the IRS-2 pathway and a subset of genes characteristic of alternatively activated macrophages. The direct effect(s) of IL-4 and IL-13 on mouse eosinophils are not clear. The goal of this study was determine the effect of IL-4 and IL-13 on mouse eosinophil function.

Methods

Standard Transwell chemotaxis assay was used to assay migration of mouse eosinophils and signal transduction was assessed by Western blotting.

Results

Here we determined that (i) mouse eosinophils express both type I and type II IL-4 receptors, (ii) in contrast to human eosinophils, mouse eosinophils do not chemotax to IL-4 or IL-13 although (iii) pre-treatment with IL-4 but not IL-13 enhanced migration to eotaxin-1. This IL-4-mediated enhancement was dependent on type I IL-4 receptor expression: γC-deficient eosinophils did not show enhancement of migratory capacity when pre-treated with IL-4. In addition, mouse eosinophils responded to IL-4 with the robust tyrosine phosphorylation of STAT6 and IRS-2, while IL-13-induced responses were considerably weaker.

Conclusions

The presence of IL-4 in combination with eotaxin-1 in the allergic inflammatory milieu could potentiate infiltration of eosinophils into the lungs. Therapies that block IL-4 and chemokine receptors on eosinophils might be more effective clinically in reducing eosinophilic lung inflammation.

PI3Ks-drug targets in inflammation and cancer

Phosphoinositide 3-kinases (PI3Ks) control cell growth, proliferation, cell survival, metabolic activity, vesicular trafficking, degranulation, and migration. Through these processes, PI3Ks modulate vital physiology. When over-activated in disease, PI3K promotes tumor growth, angiogenesis, metastasis or excessive immune cell activation in inflammation, allergy and autoimmunity. This chapter will introduce molecular activation and signaling of PI3Ks, and connections to target of rapamycin (TOR) and PI3K-related protein kinases (PIKKs). The focus will be on class I PI3Ks, and extend into current developments to exploit mechanistic knowledge for therapy.

Phosphoinositide 3-kinase p110γ in immunity

The rapid and accurate response of leukocytes to environmental cues is critical for a proper inflammatory reaction to foreign particles or invading microbes. In the last decade, the signal transduction enzyme phosphoinositide 3-kinase γ (PI3Kγ) has emerged as a critical modulator of leukocyte responses, with its effects spanning from recruitment to the site of inflammation to the production of reactive oxygen species. These findings initially obtained from genetically modified mice have led to the development of experimental anti-inflammatory inhibitors with reasonable selectivity and specificity. While such molecules have not yet reached clinical use, preclinical studies combining genetics and pharmacology continue to provide new therapeutic indications for targeting PI3Kγ. Thus, this review focuses on the latest discoveries regarding PI3Kγ function in leukocytes and on the most recent findings in disease models related to immunity.

Anti-malarial drug artesunate attenuates experimental allergic asthma via inhibition of the phosphoinositide 3-kinase/Akt pathway

BACKGROUND

Phosphoinositide 3-kinase (PI3K)/Akt pathway is linked to the development of asthma. Anti-malarial drug artesunate is a semi-synthetic derivative of artemisinin, the principal active component of a medicinal plant Artemisia annua, and has been shown to inhibit PI3K/Akt activity. We hypothesized that artesunate may attenuate allergic asthma via inhibition of the PI3K/Akt signaling pathway.

METHODOLOGY/PRINCIPAL FINDINGS

Female BALB/c mice sensitized and challenged with ovalbumin (OVA) developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Artesunate dose-dependently inhibited OVA-induced increases in total and eosinophil counts, IL-4, IL-5, IL-13 and eotaxin levels in bronchoalveolar lavage fluid. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, IL-17, IL-33 and Muc5ac in lung tissues, and airway hyperresponsiveness to methacholine. In normal human bronchial epithelial cells, artesunate blocked epidermal growth factor-induced phosphorylation of Akt and its downstream substrates tuberin, p70S6 kinase and 4E-binding protein 1, and transactivation of NF-κB. Similarly, artesunate blocked the phosphorylation of Akt and its downstream substrates in lung tissues from OVA-challenged mice. Anti-inflammatory effect of artesunate was further confirmed in a house dust mite mouse asthma model.

CONCLUSION/SIGNIFICANCE

Artesunate ameliorates experimental allergic airway inflammation probably via negative regulation of PI3K/Akt pathway and the downstream NF-κB activity. These findings provide a novel therapeutic value for artesunate in the treatment of allergic asthma.