A mechanistic perspective on the health promoting effects of alcohol - A focus on epigenetics modification

While the detrimental effects of binge drinking are well recognized, low-to-moderate alcohol consumption may be beneficial to health, although the underlying mechanism(s) remains elusive. In this opinion article, we will examine the effects of low dose alcohol consumption from the perspective of epigenetic modulation. Biochemically, alcohol is metabolized into acetate and subsequently to acetyl-coA, which can modulate histone acetylation levels. While elevated levels of acetyl-CoA are detrimental for longevity, we argue that diminished acetyl-CoA also negatively affects fatty acid biosynthesis and histone acetylation, which play a critical role in gene expression and, ultimately, health span. Since mitochondrial function and glucose metabolism, which provide the main source of nucleocytoplasmic acetyl-CoA, are compromised with age, alcohol-derived acetate could be an alternative source of acetyl-CoA to compensate. Hence, the health benefits of low ethanol consumption may be more pronounced after midlife, since mitochondrial function and/or glucose metabolism are diminished in this phase of the life course. Indeed, various clinical alcohol consumption studies concur with this notion, and have shown that a low dose of regular alcohol intake after midlife brings about various health and survival benefits. The requirement for regular alcohol intake may also reflect the transient nature of ethanol-induced histone acetylation. Conversely, ethanol may also stimulate carcinogenesis by inhibiting DNA methylation, as it was shown to reduce various pathways leading to DNA and histone methylation. However, unlike acetylation, where ethanol directly increases the substrate for acetylation, this effect was only observed in the high alcohol exposure cohort. While alcohol-derived acetate may be beneficial for health after midlife, various detrimental effects of alcohol consumption remain, and hence, we do not advocate excessive drinking to increase acetate. This opinion article establishes a possible role of ethanol-derived acetate in achieving homeostasis and sustaining an organism's health span.

Alpha-Ketoglutarate dietary supplementation to improve health in humans

Alpha-ketoglutarate (AKG) is an intermediate in the Krebs cycle involved in various metabolic and cellular pathways. As an antioxidant, AKG interferes in nitrogen and ammonia balance, and affects epigenetic and immune regulation. These pleiotropic functions of AKG suggest it may also extend human healthspan. Recent studies in worms and mice support this concept. A few studies published in the 1980s and 1990s in humans suggested the potential benefits of AKG in muscle growth, wound healing, and in promoting faster recovery after surgery. So far there are no recently published studies demonstrating the role of AKG in treating aging and age-related diseases; hence, further clinical studies are required to better understand the role of AKG in humans. This review will discuss the regulatory role of AKG in aging, as well as its potential therapeutic use in humans to treat age-related diseases.

The association of genetically determined serum glycine with cardiovascular risk in East Asians

BACKGROUND AND AIMS

Glycine is involved in a wide range of metabolic pathways and increased circulating glycine is associated with reduced risk of cardio-metabolic diseases in Europeans but the genetic association between circulating glycine and cardiovascular risk is largely unknown in East Asians.

METHODS AND RESULTS

We conducted a genome-wide association study (GWAS) in Singaporean Chinese participants and investigated if genetically determined serum glycine were associated with incident coronary artery disease (CAD) (711 cases and 1,246 controls), cardiovascular death (1,886 cases and 21,707 controls) and angiographic CAD severity (as determined by the Modified Gensini score, N = 1,138).

CONCLUSION

Our study, a first in East Asians, suggest a protective role of glycine against CAD.

Does eNOS derived nitric oxide protect the young from severe COVID-19 complications?

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Aging is the largest risk factors for severity and mortality in adult COVID-19.

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Severe cases of COVID-19 are related to vascular damage with evidence of direct viral infection in the endothelial cells.

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Increase risk of COVID-19 death are also highly related to disease with lower vascular Nitric Oxide (NO) level.

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Vascular viral defence by endothelial nitric oxide synthase (eNOS) derive NO may be the protecting factor for the young.

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eNOS polymorphism could potentially explain the disparity of COVID-19 mortality between Asian and non-Asian countries.

The COVID-19 pandemic poses an imminent threat to humanity, especially to the elderly. The molecular mechanisms underpinning the age-dependent disparity for disease progression is not clear. COVID-19 is both a respiratory and a vascular disease in severe patients. The damage endothelial system provides a good explanation for the various complications seen in COVID-19 patients. These observations lead us to suspect that endothelial cells are a barrier that must be breached before progression to severe disease. Endothelial intracellular defences are largely dependent of the activation of the interferon (IFN) system. Nevertheless, low type I and III IFNs are generally observed in COVID-19 patients suggesting that other intracellular viral defence systems are also activated to protect the young. Intriguingly, Nitric oxide (NO), which is the main intracellular antiviral defence, has been shown to inhibit a wide array of viruses, including SARS-CoV-1. Additionally, the increased risk of death with diseases that have underlying endothelial dysfunction suggest that endothelial NOS-derived nitric oxide could be the main defence mechanism. NO decreases dramatically in the elderly, the hyperglycaemic and the patients with low levels of vitamin D. However, eNOS derived NO occurs at low levels, unless it is during inflammation and co-stimulated by bradykinin. Regrettably, the bradykinin-induced vasodilation also progressively declines with age, thereby decreasing anti-viral NO production as well. Intriguingly, the inverse correlation between the percentage of WT eNOS haplotype and death per 100K population could potentially explain the disparity of COVID-19 mortality between Asian and non-Asian countries. These changes with age, low bradykinin and NO, may be the fundamental reasons that intracellular innate immunity declines with age leading to more severe COVID-19 complications.

IL13RA2 Is Differentially Regulated in Papillary Thyroid Carcinoma vs Follicular Thyroid Carcinoma

CONTEXT

The interleukin-13 receptor alpha2 (IL13RA2), which is known to be overexpressed in glioblastoma multiforme, plays a role in various cellular processes such as cell migration that may contribute to tumor progression. Studies have attributed IL13RA2 to invasion and metastasis in cancers of the ovary, breast, and pancreas, but the pathological role of IL13RA2 in thyroid cancer is still unclear.

OBJECTIVE

This study aims to evaluate IL13RA2 expression in thyroid carcinomas and to examine the role of IL13RA2 in the progression of papillary thyroid carcinoma (PTC).

METHODS

IL13RA2 immunochemical staining was performed on tissue microarrays of 137 thyroid carcinomas from patients, and the differential profile of IL13RA2 was validated in thyroid cancer cell lines. In PTC cell lines, we functionally assessed the effects of IL13RA2 underexpression and overexpression on cell proliferation, cell migration, and epithelial-mesenchymal transition (EMT) by using CCK-8, transwell migration assay, quantitative RT-PCR, and Western blot analysis.

RESULTS

IL13RA2 expression was significantly correlated with advanced tumor T stage (pT3 or pT4; P = 0.001) and regional lymph node metastasis (pN1; P < 0.001). The staining scores of IL13RA2 were significantly higher in PTC compared with follicular subtypes (P < 0.001) and correlated with advanced tumor stage among PTC samples (pT3 or pT4; P = 0.028). Knockdown of IL13RA2 in B-CPAP cells significantly reduced cell viability, cell migration, and EMT markers including N-cadherin, Vimentin, and Snail. Exogenous overexpression of IL13RA2 in K1 cells increased cell migration and EMT, although cell proliferation was not affected.

CONCLUSION

IL13RA2 is differentially regulated in PTC and is involved in cell migration by enhancing EMT.

Abstract 2780: IL13RA2 is differentially regulated in papillary thyroid carcinoma versus follicular thyroid carcinoma

The interleukin-13 receptor alpha2 (IL13RA2), which is known to overexpressed in glioblastoma multiforme, plays a role in various cellular processes such as cell migration that may contribute to tumor progression. Studies have attributed IL13RA2 to invasion and metastasis in cancers of the ovary, breast, and pancreas but the pathological role of IL13RA2 in thyroid cancer is still unclear. This study aims to evaluate the expression of IL13RA2 in thyroid carcinomas and examine the role of IL13RA2 in progression of papillary thyroid cancer (PTC). We performed IL13RA2 immunochemical staining on tissue microarrays of 137 thyroid carcinomas and observed that IL13RA2 expression was significantly correlated with advanced tumor stage (pT3 / pT4; p=0.001) and regional lymph node metastasis (pN1; p&lt;0.001). Moreover, the staining scores of IL13RA2 were significantly higher in PTC compared to follicular and anaplastic subtypes (p&lt;0.02) and correlated with advanced tumor stage amongst PTC samples (pT3 / pT4; p=0.028). This differential profile of IL13RA2 in PTC was further validated in thyroid cancer cell lines overexpressing IL13RA2 to assay the effects on cell proliferation, cell migration and epithelial-mesenchymal transition (EMT) using CCK-8, transwell migration assay, qRT-PCR and western blot analyses. Knockdown of IL13RA2 in the PTC subtype B-CPAP cell line showed significantly reduced cell viability, cell migration and EMT markers including N-cadherin, Vimentin and Snail. Exogenous overexpression of IL13RA2 in another PTC cell line, K1 increased cell migration and EMT although cell proliferation was not affected. In summary, we demonstrated that IL13RA2 is differentially regulated in PTC and is involved in cell migration by enhancing EMT. The underlying molecular mechanisms on how IL13RA2 drives progression of thyroid cancer remains to be further investigated.

Citation Format: Siao Ting Chong, Catherine Y. Kok, Khee Ming Tan, Shou Ping Guan, Siang Hui Lai, Cindy Lim, Jiancheng Hu, Charles Sturgis, Charis Eng, Paula Y. Lam, Joanne Ngeow. IL13RA2 is differentially regulated in papillary thyroid carcinoma versus follicular thyroid carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2780.

The dimer-dependent catalytic activity of RAF family kinases is revealed through characterizing their oncogenic mutants

Although extensively studied for three decades, the molecular mechanisms that regulate the RAF/MEK/ERK kinase cascade remain ambiguous. Recent studies identified the dimerization of RAF as a key event in the activation of this cascade. Here, we show that in-frame deletions in the β3-αC loop activate ARAF as well as BRAF and other oncogenic kinases by enforcing homodimerization. By characterizing these RAF mutants, we find that ARAF has less allosteric and catalytic activity than the other two RAF isoforms, which arises from its non-canonical APE motif. Further, these RAF mutants exhibit a strong oncogenic potential, and a differential inhibitor resistance that correlates with their dimer affinity. Using these unique mutants, we demonstrate that active RAFs, including the BRAF(V600E) mutant, phosphorylate MEK in a dimer-dependent manner. This study characterizes a special category of oncogenic kinase mutations, and elucidates the molecular basis that underlies the differential ability of RAF isoforms to stimulate MEK-ERK pathway. Further, this study reveals a unique catalytic feature of RAF family kinases that can be exploited to control their activities for cancer therapies.

p63(+)Krt5(+) distal airway stem cells are essential for lung regeneration

Many patients experiencing sudden loss of lung tissue somehow undergo full recovery; here this recovery is traced to a discrete population of lung stem cells that are not only essential for lung regeneration but can be cloned and then transplanted to other mice to contribute new lung tissue.

The extent to which patients can recover after massive loss of lung tissue has been unclear. However, clinical experience has shown that large-scale lung regeneration can occur in children and adults following catastrophic lung damage, and previous studies in mice have linked a subset of cells from distal airway to a regeneration process observed after H1N1 influenza virus mediated injury. Two papers published in this issue show that when the epithelial cells lining the interior of the lung are damaged, a rare stem cell population is induced to proliferate and migrate to the damaged site where they differentiate into several cell types. Frank McKeon and colleagues describe a rare subset of mouse distal airway cells that proliferate after exposure to influenza. These cells can contribute to lung regeneration after transplantation and maintain their intrinsic lineage commitment in cell culture, suggesting that such cell subsets may have potential in stem-cell-based therapies. Harold Chapman and colleagues used lineage tracing to identify a population of quiescent cells in the mouse distal lung that are activated after bleomycin or influenza-mediated injury. These cells express cytokeratin 5 and repair the epithelium through a Notch signalling pathway, although persistent Notch signalling in this context then leads to the formation of cysts. Data from patients suffering from lung fibrosis also show the presence of hyperactive Notch and similar cysts.

Lung diseases such as chronic obstructive pulmonary disease¹ and pulmonary fibrosis² involve the progressive and inexorable destruction of oxygen exchange surfaces and airways, and have emerged as a leading cause of death worldwide. Mitigating therapies, aside from impractical organ transplantation, remain limited and the possibility of regenerative medicine has lacked empirical support. However, it is clinically known that patients who survive sudden, massive loss of lung tissue from necrotizing pneumonia^3,4 or acute respiratory distress syndrome^5,6 often recover full pulmonary function within six months. Correspondingly, we recently demonstrated lung regeneration in mice following H1N1 influenza virus infection, and linked distal airway stem cells expressing Trp63 (p63) and keratin 5, called DASC^p63/Krt5, to this process⁷. Here we show that pre-existing, intrinsically committed DASC^p63/Krt5 undergo a proliferative expansion in response to influenza-induced lung damage, and assemble into nascent alveoli at sites of interstitial lung inflammation. We also show that the selective ablation of DASC^p63/Krt5in vivo prevents this regeneration, leading to pre-fibrotic lesions and deficient oxygen exchange. Finally, we demonstrate that single DASC^p63/Krt5-derived pedigrees differentiate to type I and type II pneumocytes as well as bronchiolar secretory cells following transplantation to infected lung and also minimize the structural consequences of endogenous stem cell loss on this process. The ability to propagate these cells in culture while maintaining their intrinsic lineage commitment suggests their potential in stem cell-based therapies for acute and chronic lung diseases.

Anti-allergic actions of rottlerin from Mallotus philippinensis in experimental mast cell-mediated anaphylactic models

Allergy is an acquired hypersensitivity reaction of the immune system mediated by cross-linking of the allergen-specific IgE-bound high-affinity IgE receptors, leading to immediate mast cell degranulation. Rottlerin is an active molecule isolated from Mallotus philippinensis, a medicinal plant used in Ayurvedic Medicine System for anti-allergic and anti-helminthic treatments. The present study investigated potential anti-allergic effects of rottlerin in animal models of IgE-dependent anaphylaxis and the anti-allergic mechanisms of action of rottlerin in mast cells. Anti-allergic actions of rottlerin were evaluated in passive cutaneous anaphylaxis and passive systemic anaphylaxis mouse models, and in anaphylactic contraction of bronchial rings isolated from sensitized guinea pigs. Direct mast cell-stabilizing effect of rottlerin was examined in RBL-2H3 mast cell line. Anti-allergic signaling mechanisms of action of rottlerin in mast cells were also examined. Rottlerin prevented IgE-mediated cutaneous vascular extravasation, hypothermia, elevation in plasma histamine level and tracheal tissue mast cell degranulation in mice in a dose-dependent manner. In addition, rottlerin suppressed ovalbumin-induced guinea pig bronchial smooth muscle contraction. Furthermore, rottlerin concentration-dependently blocked IgE-mediated immediate release of β-hexosaminidase from RBL-2H3 mast cells. Rottlerin was found to inhibit IgE-induced PLCγ1 and Akt phosphorylation, production of IP3 and rise in cytosolic Ca²⁺ level in mast cells. We report here for the first time that rottlerin possesses anti-allergic activity by blocking IgE-induced mast cell degranulation, providing a foundation for developing rottlerin for the treatment of allergic asthma and other mast cell-mediated allergic disorders.

Laminin drives survival signals to promote a contractile smooth muscle phenotype and airway hyperreactivity

Increased airway smooth muscle (ASM) mass is believed to underlie the relatively fixed airway hyperresponsiveness (AHR) in asthma. Developments of therapeutic approaches to reverse airway remodeling are impeded by our lack of insight on the mechanisms behind the increase in mass of contractile ASM cells. Increased expression of laminin, an extracellular matrix protein, is associated with asthma. Our studies investigate the role of laminin-induced ASM survival signals in the development of increased ASM and AHR. Antagonizing laminin integrin binding using the laminin-selective competing peptide, YIGSR, and mimicking laminin with exogenous α2-chain laminin, we show that laminin is both necessary and sufficient to induce ASM cell survival, concomitant with the induction of ASM contractile phenotype. Using siRNA, we show that the laminin-binding integrin α7β1 mediates this process. Moreover, in laminin-211-deficient mice, allergen-induced AHR was not observed. Notably, ASM cells from asthmatic airways express a higher abundance of intracellular cell survival proteins, consistent with a role for reduced rates of cell apoptosis in development of ASM hyperplasia. Targeting the laminin-integrin α7β1 signaling pathway may offer new avenues for the development of therapies to reduce the increase in mass of contractile phenotype ASM cells that underlie AHR in asthma.

Andrographolide protects against cigarette smoke-induced oxidative lung injury via augmentation of Nrf2 activity

BACKGROUND AND PURPOSE

Cigarette smoke is a major cause for chronic obstructive pulmonary disease (COPD). Andrographolide is an active biomolecule isolated from the plant Andrographis paniculata. Andrographolide has been shown to activate nuclear factor erythroid-2-related factor 2 (Nrf2), a redox-sensitive antioxidant transcription factor. As Nrf2 activity is reduced in COPD, we hypothesize that andrographolide may have therapeutic value for COPD.

EXPERIMENTAL APPROACH

Andrographolide was given i.p. to BALB/c mice daily 2h before 4% cigarette smoke exposure for 1h over five consecutive days. Bronchoalveolar lavage fluid and lungs were collected for analyses of cytokines, oxidative damage markers and antioxidant activities. BEAS-2B bronchial epithelial cells were exposed to cigarette smoke extract (CSE) and used to study the antioxidant mechanism of action of andrographolide.

KEY RESULTS

Andrographolide suppressed cigarette smoke-induced increases in lavage fluid cell counts; levels of IL-1β, MCP-1, IP-10 and KC; and levels of oxidative biomarkers 8-isoprostane, 8-OHdG and 3-nitrotyrosine in a dose-dependent manner. Andrographolide promoted inductions of glutathione peroxidase (GPx) and glutathione reductase (GR) activities in lungs from cigarette smoke-exposed mice. In BEAS-2B cells, andrographolide markedly increased nuclear Nrf2 accumulation, promoted binding to antioxidant response element (ARE) and total cellular glutathione level in response to CSE. Andrographolide up-regulated ARE-regulated gene targets including glutamate-cysteine ligase catalytic (GCLC) subunit, GCL modifier (GCLM) subunit, GPx, GR and heme oxygenase-1 in BEAS-2B cells in response to CSE.

CONCLUSIONS

Andrographolide possesses antioxidative properties against cigarette smoke-induced lung injury probably via augmentation of Nrf2 activity and may have therapeutic potential for treating COPD.

Annexin-1-deficient mice exhibit spontaneous airway hyperresponsiveness and exacerbated allergen-specific antibody responses in a mouse model of asthma

BACKGROUND

Glucocorticoids are the mainstream drugs used in the treatment and control of inflammatory diseases such as asthma. Annexin-1 (ANXA1) is an anti-inflammatory protein which has been described as an endogenous protein responsible for some anti-inflammatory glucocorticoid effects. Previous studies have identified its importance in other immune diseases such as rheumatoid arthritis and cystic fibrosis. ANXA1-deficient ((-/-)) mice are Th2 biased, and ANXA1 N-terminus peptide exhibits anti-inflammatory activity in a rat model of pulmonary inflammation.

OBJECTIVE

ANXA1 protein is found in bronchoalveolar lavage fluid from asthmatics. However, the function of ANXA1 in the pathological development of allergy or asthma is unclear. Thus, in this study we intended to examine the effect of ANXA1 deficiency on allergen-specific antibody responses and airway responses to methacholine (Mch).

METHODS

ANXA1(-/-) mice were sensitized with ovalbumin (OVA) and challenged with aerosolized OVA. Airway resistance, lung compliance and enhanced pause (PenH) were measured in naïve, sensitized and saline or allergen-challenged wild-type (WT) and ANXA1(-/-) mice. Total and allergen-specific antibodies were measured in the serum.

RESULTS

We show that allergen-specific and total IgE, IgG2a and IgG2b levels were significantly higher in ANXA1(-/-) mice. Furthermore, naïve ANXA1(-/-) mice displayed higher airway hypersensitivity to inhaled Mch, and significant differences were also observed in allergen-sensitized and allergen-challenged ANXA1(-/-) mice compared with WT mice.

CONCLUSIONS

In conclusion, ANXA1(-/-) mice possess multiple features characteristic to allergic asthma, such as airway hyperresponsiveness and enhanced antibody responses, suggesting that ANXA1 plays a critical regulatory role in the development of asthma.

CLINICAL RELEVANCE

We postulate that ANXA1 is an important regulatory factor in the development of allergic disease and dysregulation of its expression can lead to pathological changes which may affect disease progression.

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.

Antigen-specific effector CD8 T-cells inhibit allergic responses via IFN-gamma secretion and dendritic cell interaction (103.4)

Allergic inflammation of the airways causes changes in the lung wall that lead to inflammatory diseases such as asthma. Using a mouse model this response can be divided into an induction phase and an effector phase. Previously we have shown that transfer of CD8 T cells inhibits the induction of Th2 responses. In this study we have investigated the effect of CD8 T cells on the effector phase of the inflammatory lung response. In vitro activated OT-I CD8 T cells were transferred to ovalbumin (OVA)-alum immunized mice one day before challenge with OVA. Eosinophil infiltration and mucus secretion were inhibited by transfer of CD8 T cells. When OT-IxIFN-gamma-/-T cells were transferred, the inhibitory effect was abolished, suggesting an important role for IFN-gamma. In fact, without IFN-gamma, effector CD8 T cells were able to induce asthma-like inflammation which further proved the importance of IFN-gamma in the suppression of type II inflammation. We also investigated the effect of CD8 T cells on lung dendritic cell (DC) function. CD11c+CD11b+CD103- DCs from CD8 transferred mice increased largely in number and when co-cultured with CD4 T cells, they were able to induce more IFN-gamma production. These results suggest that in addition to regulating the induction of the allergic immune response, CD8 T cells can subsequently divert the local lung environment to one that favors Th1 immunity, through IFN-gamma and CD8-DC interaction.

A Novel Anti-Inflammatory Role for Andrographolide in Asthma via Inhibition of The Nuclear Factor-kappaB Pathway (140.17)

Persistent activation of nuclear factor (NF)-κB has been associated with the development of asthma. Andrographolide, the principal active component of a medicinal plant Andrographis paniculata, has been shown to inhibit NF-κB activity. We hypothesized that andrographolide may attenuate allergic asthma via inhibition of the NF-κB signaling pathway. BALB/c mice sensitized and challenged with OVA developed airway inflammation. Andrographolide inhibited OVA-induced increases in total cell count, eosinophil count, and IL-4, IL-5 and IL-13 levels in bronchoalveolar lavage fluid, and reduced serum level of OVA-specific IgE. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, chitinases, Muc5ac and inducible nitric oxide synthase in lung tissues, and airway hyperresponsiveness to methacholine. In human lung epithelial cells, andrographolide blocked TNF-α-induced phosphorylation of inhibitory κB (IκB) kinase-β (IKKβ), and downstream IκBα degradation, p65 subunit of NF-κB phosphorylation, and p65 nuclear translocation and DNA-binding activity. Our findings implicate a potential therapeutic value of andrographolide in the treatment of asthma and it may act by inhibiting NF-κB pathway at the level of IKKβ activation. (This work was supported by a BioMedical Research Council grant BMRC06/1/21/19/443)