Alismol Purified from the Tuber of Alisma orientale Relieves Acute Lung Injury in Mice via Nrf2 Activation.

Since the ethanol extract of Alisma orientale Juzepzuk (EEAO) suppresses lung inflammation by suppressing Nuclear Factor-kappa B (NF-κB) and activating Nuclear Factor Erythroid 2-related Factor 2 (Nrf2), we set out to identify chemicals constituting EEAO that suppress lung inflammation. Here, we provide evidence that among the five most abundant chemical constituents identified by Ultra Performance Liquid Chromatography (UPLC) and Nuclear Magnetic Resonance (NMR), alismol is one of the candidate constituents that suppresses lung inflammation in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model and protects mice from ALI-like symptoms. Alismol did not induce cytotoxicity or reactive oxygen species (ROS). When administered to the lung of LPS-induced ALI mice (n = 5/group), alismol decreased the level of neutrophils and of the pro-inflammatory molecules, including Tumor Necrosis Factor-alpha (TNF-α), Interleukin-1 beta (IL-1ß), Interleukin-6 (IL-6), Monocyte Chemoattractant Protein-1 (MCP-1), Interferon-gamma (IFN-γ), and Cyclooxygenase-2 (COX-2), suggesting an anti-inflammatory activity of alismol. Consistent with these findings, alismol ameliorated the key features of the inflamed lung of ALI, such as high cellularity due to infiltrated inflammatory cells, the development of hyaline membrane structure, and capillary destruction. Unlike EEAO, alismol did not suppress NF-κB activity but rather activated Nrf2. Consequently, alismol induced the expression of prototypic genes regulated by Nrf2, including Heme Oxygenase-1 (HO-1), NAD(P)H: quinine oxidoreductase-1 (NQO-1), and glutamyl cysteine ligase catalytic units (GCLC). Alismol activating Nrf2 appears to be associated with a decrease in the ubiquitination of Nrf2, a key suppressive mechanism for Nrf2 activity. Together, our results suggest that alismol is a chemical constituent of EEAO that contributes at least in part to suppressing some of the key features of ALI by activating Nrf2.

The ethanol extract of Garcinia subelliptica Merr. induces autophagy.

BACKGROUND: Garcinia subelliptica Merr. is a multipurpose coastal tree, the potential medicinal effects of which have been studied, including cancer suppression. Here, we present evidence that the ethanol extract of G. subelliptica Merr. (eGSM) induces autophagy in human lung adenocarcinoma cells. METHODS: Two different human lung adenocarcinoma cell lines, A549 and SNU2292, were treated with varying amounts of eGSM. Cytotoxicity elicited by eGSM was assessed by MTT assay and PARP degradation. Autophagy in A549 and SNU2292 was determined by western blotting for AMPK, mTOR, ULK1, and LC3. Genetic deletion of AMPKα in HEK293 cells was carried out by CRISPR. RESULTS: eGSM elicited cytotoxicity, but not apoptosis, in A549 and SNU2292 cells. eGSM increased LC3-II production in both A549 and, more extensively, SNU2292, suggesting that eGSM induces autophagy. In A549, eGSM activated AMPK, an essential autophagy activator, but not suppressed mTOR, an autophagy blocker, suggesting that eGSM induces autophagy by primarily activating the AMPK pathway in A549. By contrast, eGSM suppressed mTOR activity without activating AMPK in SNU2292, suggesting that eGSM induces autophagy by mainly suppressing mTOR in SNU2292. In HEK293 cells lacking AMPKα expression, eGSM increased LC3-II production, confirming that the autophagy induced by eGSM can occur without the AMPK pathway. CONCLUSION: Our findings suggest that eGSM induces autophagy by activating AMPK or suppressing mTOR pathways, depending on cell types.

Multifactorial Traits of SARS-CoV-2 Cell Entry Related to Diverse Host Proteases and Proteins.

The most effective way to control newly emerging infectious disease, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, is to strengthen preventative or therapeutic public health strategies before the infection spreads worldwide. However, global health systems remain at the early stages in anticipating effective therapeutics or vaccines to combat the SARS-CoV-2 pandemic. While maintaining social distance is the most crucial metric to avoid spreading the virus, symptomatic therapy given to patients on the clinical manifestations helps save lives. The molecular properties of SARS-CoV-2 infection have been quickly elucidated, paving the way to therapeutics, vaccine development, and other medical interventions. Despite this progress, the detailed biomolecular mechanism of SARS-CoV-2 infection remains elusive. Given virus invasion of cells is a determining factor for virulence, understanding the viral entry process can be a mainstay in controlling newly emerged viruses. Since viral entry is mediated by selective cellular proteases or proteins associated with receptors, identification and functional analysis of these proteins could provide a way to disrupt virus propagation. This review comprehensively discusses cellular machinery necessary for SARS-CoV-2 infection. Understanding multifactorial traits of the virus entry will provide a substantial guide to facilitate antiviral drug development.

The role of Korean Medicine in the post-COVID-19 era: an online panel discussion part 2 - basic research and education.

BACKGROUND: Experiencing difficulties and challenges though COVID-19 pandemic, there are voices that it needs to be discussed to seek direction of basic research and college education of Korean Medicine (KM) so that KM community can play a significant role in the future infectious disease outbreaks. METHODS: This paper summarizes the edited highlights of an online video meeting by Google meet on May 19, 2020, organized by the Korean Medicine Convergence Research Information Center. Five researchers specialized in immunology, microbiology, virology, preventive medicine, and herbology, respectively, presented what KM community should prepare for the future acute infectious disease outbreaks by learning from the previous research on antiviral effect of herbs for coronavirus and the experiences of the present COVID-19 pandemic. RESULTS: There are a lot of herbs or natural products with potential anti-coronavirus effects reported from in vitro experiments and despite criticism, many clinical trials on traditional herbal medicine for COVID-19 are being conducted. In addition to establishing research evidence, KM community should train and produce public health professionals among Korean Medicine Doctors (KMDs) and official participation in public healthcare system should be ensured in terms of regulation and policy. Newly developed KM treatments can be interpreted by the KM theories and also should be allowed by regulations for KMDs to utilize them. CONCLUSION: The present online discussion suggested directions of basic research for acute viral infections diseases utilizing KM and how to enforce relevant education and regulations in the post-COVID-19 era.

Sikyungbanha-Tang Suppressing Acute Lung Injury in Mice Is Related to the Activation of Nrf2 and TNFAIP3.

Sikyungbanha-Tang (SKBHT) is a Chinese traditional medicine popularly prescribed to patients with respiratory inflammatory symptoms in Korea. Although the Korea Food and Drug Administration approved SKBHT as a therapeutics for relieving the symptoms, experimental evidence for SKBHT suppressing inflammation is scarce. Here, we presented evidence that SKBHT can suppress inflammation in an acute lung injury (ALI) mouse model and explored the possible underlying mechanisms of SKBHT's anti-inflammatory activity. Single intratracheal (i.t.) injection of SKBHT (1 mg/kg or 10 mg/kg body weight) into mouse lungs decreased prototypic features of lung inflammation found in ALI, such as a high level of proinflammatory cytokines, neutrophil infiltration, and the formation of hyaline membrane, which were induced by a single i.t. LPS (2 mg/kg body weight). When added to a murine macrophage RAW 264.7 cells, SKBHT activated an anti-inflammatory factor Nrf2, increasing the expression of genes regulated by Nrf2. SKBHT suppressed the ubiquitination of Nrf2, suggesting that SKBHT increases the level of and thus activates Nrf2 by blunting the ubiquitin-dependent degradation of Nrf2. SKBHT induced the expression of tumor necrosis factor α-induced protein 3 (TNFAIP3), an ubiquitin-modulating protein that suppresses various cellular signals to NF-κB. Concordantly, SKBHT suppressed NF-κB activity and the expression of inflammatory cytokine genes regulated by NF-κB. Given that Nrf2 and TNFAIP3 are involved in regulating inflammation, our results suggest that SKBHT suppresses inflammation in the lung, the effect of which is related to SKBHT activating Nrf2 and TNFAIP3.

The methanol extract of Guettarda speciosa Linn. Ameliorates acute lung injury in mice.

BACKGROUND: Guettarda speciosa is mainly found in tropical areas in Asia. Although G. speciosa is traditionally used to treat some of the inflammatory disorders, the experimental evidence supporting the anti-inflammatory effect of G. speciosa is limited. Here, we sought to obtain evidence that G. speciosa has anti-inflammatory activity using an acute lung injury (ALI) mouse model and to explore possible underlying mechanisms for the activity. METHODS: The methanol extract of G. speciosa Linn. (MGS) was fingerprinted by HPLC. Cytotoxicity was determined by MTT and flow cytometer. As for an ALI mouse model, C57BL/6 mice received an intratracheal (i.t.) injection of lipopolysaccharide (LPS). The effects of MGS on lung inflammation in the ALI mice were assessed by differential cell counting and FACS of inflammatory cells and hematoxylin and eosin staining of lung tissue. Proteins were analyzed by immunoprecipitation and immunoblotting, and gene expression was by real-time qPCR. Neutrophil elastase activity was measured by ELISA. RESULTS: MGS did not cause metabolic disarray or produce reactive oxygen species that could induce cytotoxicity. Similar to ALI patients, C57BL/6 mice that received an i.t. LPS developed a high level of neutrophils, increased pro-inflammatory cytokines, and inflicted tissue damage in the lung, which was suppressed by i.t. MGS administered at 2 h after LPS. Mechanistically, MGS activated Nrf2, which was related to MGS interrupting the ubiquitin-dependent degradation of Nrf2. MGS suppressed the nuclear localization of NF-κB induced by LPS, suggesting the inhibition of NF-κB activity. Furthermore, MGS inhibited the enzymatic activity of neutrophil elastase. CONCLUSION: MGS could suppress lung inflammation in an ALI mouse model, the effect of which could be attributed to multiple mechanisms, including the activation of Nrf2 and the suppression of NF-κB and neutrophil elastase enzymatic activity by MGS.

Heme oxygenase-1 induced by desoxo-narchinol-A attenuated the severity of acute pancreatitis via blockade of neutrophil infiltration.

Heme oxygenase-1 (HO-1) has an anti-inflammatory action in acute pancreatitis (AP). However, its mechanism of action and natural compounds/drugs to induce HO-1 in pancreas are not well understood. In this study, we investigated the regulatory mechanisms of HO-1 during AP using desoxo-narchinol-A (DN), the natural compound inducing HO-1 in the pancreas. Female C57/BL6 Mice were intraperitoneally injected with supramaximal concentrations of cerulein (50 µg/kg) hourly for 6 h to induce AP. DMSO or DN was administered intraperitoneally, then mice were sacrificed 6 h after the final cerulein injection. Administration of DN increased pancreatic HO-1 expression through activation of activating protein-1, mediated by mitogen-activated protein kinases. Furthermore, DN treatment reduced the pancreatic weight-to-body weight ratio as well as production of digestive enzymes and pro-inflammatory cytokines. Inhibition of HO-1 by tin protoporphyrin IX abolished the protective effects of DN on pancreatic damage. Additionally, DN treatment inhibited neutrophil infiltration into the pancreas via regulation of chemokine (C-X-C motif) ligand 2 (CXCL2) by HO-1. Our results suggest that DN is an effective inducer of HO-1 in the pancreas, and that HO-1 regulates neutrophil infiltration in AP via CXCL2 inhibition.

Suppression of lung inflammation by the ethanol extract of Chung-Sang and the possible role of Nrf2.

BACKGROUND: Asian traditional herbal remedies are typically a concoction of a major and several complementary herbs. While balancing out any adverse effect of the major herb, the complementary herbs could dilute the efficacy of the major herb, resulting in a suboptimal therapeutic effect of an herbal remedy. Here, we formulated Chung-Sang (CS) by collating five major herbs, which are used against inflammatory diseases, and tested whether an experimental formula composed of only major herbs is effective in suppressing inflammation without significant side effects. METHODS: The 50% ethanol extract of CS (eCS) was fingerprinted by HPLC. Cytotoxicity to RAW 264.7 cells was determined by an MTT assay and a flow cytometer. Nuclear NF-κB and Nrf2 were analyzed by western blot. Ubiquitinated Nrf2 was similarly analyzed following immunoprecipitation of Nrf2. Acute lung inflammation and sepsis were induced in C57BL/6 mice. The effects of eCS on lung disease were measured by HE staining of lung sections, a differential cell counting of bronchoalveolar lavage fluid, a myeloperoxidase (MPO) assay, a real-time qPCR, and Kaplan-Meier survival of mice. RESULTS: eCS neither elicited cytotoxicity nor reactive oxygen species. While not suppressing NF-κB, eCS activated Nrf2, reduced the ubiquitination of Nrf2, and consequently induced the expression of Nrf2-dependent genes. In an acute lung inflammation mouse model, an intratracheal (i.t.) eCS suppressed neutrophil infiltration, the expression of inflammatory cytokine genes, and MPO activity. In a sepsis mouse model, a single i.t. eCS was sufficient to significantly decrease mouse mortality. CONCLUSIONS: eCS could suppress severe lung inflammation in mice. This effect seemed to associate with eCS activating Nrf2. Our findings suggest that herbal remedies consisting of only major herbs are worth considering.

Anti-inflammatory activity of the decoction of Forsythia suspensa (Thunb.) Vahl is related to Nrf2 and A20.

ETHNOPHARMACOLOGICAL RELEVANCE: The water extract of Forsythiae Fructus (WFF) is an herbal remedy that is prescribed to treat various inflammatory diseases in traditional Chinese medicine. Although the anti-inflammatory activity of WFF has been reported, the underlying mechanisms for the activity remain unclear. Here, we examined whether the anti-inflammatory activity of WFF is associated with Nrf2, an anti-inflammatory factor, and A20, an ubiquitin-regulator protein that inhibits signaling cascades of endotoxin or cytokines. MATERIALS AND METHODS: The water extract of Forsythia suspensa (Thunb.) Vahl was prepared and fingerprinted by HPLC. Cytotoxicity and intracellular ROS induced by WFF were determined by MTT and FACS analyses, respectively. Nuclear and cytoplasmic proteins were analyzed by immunoblot. Expression of mRNA was analyzed by a semi-quantitative RT-PCR. Expression of proteins or genes was quantitated by Image J. RESULTS: WFF activated Nrf2, inducing the expression of Nrf2-dependent genes, such as HO-1, NQO1, and GCLC in RAW 264.7 cells. On the other hand, WFF suppressed NF-κB induced by LPS or TNF-α, which was coincided with the expression of A20. Conversely, WFF failed to suppress NF-κB when A20 expression was silenced by siRNA. CONCLUSION: WFF activated Nrf2 and expressed A20. Given that Nrf2 suppresses inflammation and A20 broadly disrupts inflammatory signaling cascades, our results suggest that the anti-inflammatory activity of WFF is attributable to Nrf2 and A20.

Alternative and Natural Therapies for Acute Lung Injury and Acute Respiratory Distress Syndrome.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) is a complex clinical syndrome characterized by acute inflammation, microvascular damage, and increased pulmonary vascular and epithelial permeability, frequently resulting in acute respiratory failure and death. Current best practice for ARDS involves "lung-protective ventilation," which entails low tidal volumes and limiting the plateau pressures in mechanically ventilated patients. Although considerable progress has been made in understanding the pathogenesis of ARDS, little progress has been made in the development of specific therapies to combat injury and inflammation. AREAS COVERED: In recent years, several natural products have been studied in experimental models and have been shown to inhibit multiple inflammatory pathways associated with acute lung injury and ARDS at a molecular level. Because of the pleiotropic effects of these agents, many of them also activate antioxidant pathways through nuclear factor erythroid-related factor 2, thereby targeting multiple pathways. Several of these agents are prescribed for treatment of inflammatory conditions in the Asian subcontinent and have shown to be relatively safe. EXPERT COMMENTARY: Here we review natural remedies shown to attenuate lung injury and inflammation in experimental models. Translational human studies in patients with ARDS may facilitate treatment of this devastating disease.

Hominis placenta Suppresses Acute Lung Inflammation by Activating Nrf2.

Hominis placenta (HP), a dried human placenta, has been known to target liver, lung, or kidney meridians, improving the functions associated with these meridians in traditional Chinese or Asian medicine (TCM). Since recent studies implicate an HP extract in suppressing inflammation, we investigated whether an aqueous HP extract can ameliorate inflammation that occurred in the lungs. When administered with a single intratracheal lipopolysaccharide (LPS), C57BL/6 mice developed an acute neutrophilic lung inflammation along with an increased expression of pro-inflammatory cytokine genes. However, this was diminished by the administration HP extract via an intraperitoneal route 2 h after LPS treatment. Western blot and semi-quantitative RT-PCR analyses revealed that while suppressing the activity of a proinflammatory factor NF-[Formula: see text]B marginally, the HP extract strongly activated an anti-inflammatory factor Nrf2, with concomitant expression of Nrf2-dependent genes. Mechanistically, the HP extract suppressed the ubiquitin-mediated degradation of Nrf2, functioning similarly to a 26S proteasome inhibitor, MG132. Collectively, these results suggest that the HP extract suppresses inflammation in mouse lungs, which is in part related to the HP extract perturbing the ubiquitin-dependent degradation of Nrf2 and thus increasing the function of Nrf2.

Differential Regulation of NF-κB and Nrf2 by Bojungikki-Tang Is Associated with Suppressing Lung Inflammation.

Bojungikki-tang (BT), an Asian herbal remedy, has been prescribed to increase the vitality of debilitated patients. Since a compromised, weakened vitality often leads to illness, BT has been widely used to treat various diseases. However, little is known about the mechanism by which BT exerts its effect. Given that BT ameliorates inflammatory pulmonary diseases including acute lung injury (ALI), we investigated whether BT regulates the function of key inflammatory factors such as NF-κB and Nrf2, contributing to suppressing inflammation. Results show that BT interrupted the nuclear localization of NF-κB and suppressed the expression of the NF-κB-dependent genes in RAW 264.7 cells. In similar experiments, BT induced the nuclear localization of Nrf2 and the expression of the Nrf2-dependent genes. In a lipopolysaccharide-induced ALI mouse model, a single intratracheal administration of BT to mouse lungs ameliorated alveolar structure and suppressed the expression of proinflammatory cytokine genes and neutrophil infiltration to mouse lungs. Therefore, our findings suggest that suppression of NF-κB and activation of Nrf2, by which BT suppresses inflammation, are ways for BT to exert its effect.

Suppression of lung inflammation by the methanol extract of Spilanthes acmella Murray is related to differential regulation of NF-κB and Nrf2.

ETHNOPHARMACOLOGICAL RELEVANCE: Although Spilanthes acmella has been used to relieve inflammation, fever, pain, or infection in traditional Asian medicine, experimental evidence supporting these functions is scarce. Here, we examined an anti-inflammatory function and a possible underlying mechanism of S. acmella Murray (SAM). MATERIALS AND METHOD: The methanol extract of SAM was fingerprinted by HPLC. C57BL/6 mice were administered with a single intratracheal (i.t.) LPS and 2 h later with a single i.t. SAM. The effect of SAM on lung inflammation was assessed by histology, semi-quantitative RT-PCR, and MPO assay of lung tissue. The effects of SAM on a pro-inflammatory factor NF-κB and an anti-inflammatory factor Nrf2 were analyzed by immunoblotting of nuclear proteins and by semi-quantitative RT-PCR analysis of mRNA of the genes governed by these transcription factors. V5-Nrf2 was precipitated by an anti-V5 antibody and the ubiquitinated V5-Nrf2 was revealed by immunoblotting of HA-tagged ubiquitin. RESULTS: The i.t. SAM robustly diminished a neutrophilic lung inflammation induced by i.t. LPS treatment of mice. In RAW 264.7 cells, SAM suppressed the nuclear localization of NF-κB and the expression of NF-κB-dependent cytokine genes. SAM increased the level of Nrf2 in the nucleus and the expression of Nrf2-dependent genes while suppressing ubiquitination of Nrf2. CONCLUSION: Our results suggest that SAM can suppress a neutrophilic inflammation in mouse lungs, which is associated with suppressed NF-κB and activated Nrf2. Our results provide experimental evidence supporting the anti-inflammatory function of S. acmella.

Glycosylation Enhances the Physicochemical Properties of Caffeic Acid Phenethyl Ester.

In this study, we synthesized a glycosylated derivative of caffeic acid phenethyl ester (CAPE) using the amylosucrase from Deinococcus geothermalis with sucrose as a substrate and examined its solubility, chemical stability, and anti-inflammatory activity. Nuclear magnetic resonance spectroscopy showed that the resulting glycosylated CAPE (G-CAPE) was the new compound caffeic acid phenethyl ester-4-O-α-D-glucopyranoside. G-CAPE was 770 times more soluble than CAPE and highly stable in Dulbecco's modified Eagle's medium and buffered solutions, as estimated by its half-life. The glycosylation of CAPE did not significantly affect its anti-inflammatory activity, which was assessed by examining lipopolysaccharide-induced nitric oxide production and using a nuclear factor erythroid 2-related factor 2 reporter assay. Furthermore, a cellular uptake experiment using high-performance liquid chromatography analysis of the cell-free extracts of RAW 264.7 cells demonstrated that G-CAPE was gradually converted to CAPE within the cells. These results demonstrate that the glycosylation of CAPE increases its bioavailability by helping to protect this vital molecule from chemical or enzymatic oxidation, indicating that G-CAPE is a promising candidate for prodrug therapy.

Suppressed ubiquitination of Nrf2 by p47phox contributes to Nrf2 activation.

Although critical in phagocytosis in innate immunity, reactive oxygen species (ROS) collaterally inflict damage to host phagocytes because they indiscriminate targets. Since Nrf2 increases the expression of anti-oxidant enzymes that nullifies ROS, ROS activating Nrf2 is a critical negative regulatory step for countering the deleterious effects of ROS. Here, we postulate whether, along with ROS activating Nrf2, NADPH oxidase components also participate in direct activation of Nrf2, contributing to protection from ROS. Our results show that the p47phox of the NADPH oxidase, but not p65phox or p40phox, physically binds to Nrf2, activating the Nrf2 function. p47phox binding to Nrf2/Keap1 complex suppresses the ubiquitination of Nrf2, while p47phox becomes ubiquitinated by Keap1. p47phox increases the nuclear translocation of Nrf2 and the expression of Nrf2-dependent genes, whereas genetic ablation of p47phox decreases the expression of those genes. In a lipopolysaccharide-induced acute lung inflammation mouse model, selective expression of p47phox in mouse lungs induces the expression of Nrf2-dependent genes and is sufficient to suppress neutrophilic lung inflammation. Therefore, our findings suggest that p47phox is a novel regulator of Nrf2 function.

Kaurenoic acid activates TGF-ß signaling.

BACKGROUND: Kaurenoic acid (ent-kaur-16-en-19-oic acid: KA) is a key constituent found in the roots of Aralia continentalis Kitagawa (Araliaceae) that has been used for treating rheumatism in traditional Asian medicine. HYPOTHESIS: Although KA was reported to suppress inflammation by activating Nrf2, the anti-inflammatory function of KA is less characterized. Given the complex nature of the inflammatory response and the critical role of TGF-ß in resolving inflammation, we hypothesized that KA suppresses inflammatory response by activating TGF-ß signaling. METHODS: Murine macrophage RAW 264.7, human lung epithelial cell MRC-5, and a TGFßRII defective cell HCT116 were treated with various amounts of KA. KA was also administered to mouse lung via intratracheal (i.t.) route. Phosphorylated Smad2 and Smad3 were analyzed by western blot. TGFß-dependent gene expression was determined by immunoblotting of α-SMA and luciferase assay. RESULTS: KA induced the phosphorylation of Smad2 and Smad3, key activator molecules in TGF-ß signaling. EW7197, an inhibitor for activin receptor-like kinase 5/TGF-ß receptor I (TGFßR1) suppressed KA-mediated phosphorylation of Smad2. Similarly, KA failed to phosphorylate Smad2 in HCT116, suggesting that KA acts through the prototypic TGFßR. KA treatment increased the transcriptional activity driven by a Smad-binding element in a luciferase reporter assay and induced the α-smooth muscle actin (α-SMA). Similarly, i.t. KA induced the phosphorylation of Smad2 and increased the expression ofα-SMA in mouse lungs. CONCLUSION: KA activated TGF-ß signaling, suggesting that TGFß signaling is associated with KA suppressing inflammation.

Peroxisome proliferator-activated receptor-γ agonists attenuate biofilm formation by Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a significant contributor to recalcitrant multidrug-resistant infections, especially in immunocompromised and hospitalized patients. The pathogenic profile of P. aeruginosa is related to its ability to secrete a variety of virulence factors and to promote biofilm formation. Quorum sensing (QS) is a mechanism wherein P. aeruginosa secretes small diffusible molecules, specifically acyl homo serine lactones, such as N-(3-oxo-dodecanoyl)-l-homoserine lactone (3O-C12-HSL), that promote biofilm formation and virulence via interbacterial communication. Strategies that strengthen the host's ability to inhibit bacterial virulence would enhance host defenses and improve the treatment of resistant infections. We have recently shown that peroxisome proliferator-activated receptor γ (PPARγ) agonists are potent immunostimulators that play a pivotal role in host response to virulent P. aeruginosa Here, we show that QS genes in P. aeruginosa (strain PAO1) and 3O-C12-HSL attenuate PPARγ expression in bronchial epithelial cells. PAO1 and 3O-C12-HSL induce barrier derangements in bronchial epithelial cells by lowering the expression of junctional proteins, such as zonula occludens-1, occludin, and claudin-4. Expression of these proteins was restored in cells that were treated with pioglitazone, a PPARγ agonist, before infection with PAO1 and 3O-C12-HSL. Barrier function and bacterial permeation studies that have been performed in primary human epithelial cells showed that PPARγ agonists are able to restore barrier integrity and function that are disrupted by PAO1 and 3O-C12-HSL. Mechanistically, we show that these effects are dependent on the induction of paraoxonase-2, a QS hydrolyzing enzyme, that mitigates the effects of QS molecules. Importantly, our data show that pioglitazone, a PPARγ agonist, significantly inhibits biofilm formation on epithelial cells by a mechanism that is mediated via paraoxonase-2. These findings elucidate a novel role for PPARγ in host defense against P. aeruginosa Strategies that activate PPARγ can provide a therapeutic complement for treatment of resistant P. aeruginosa infections.-Bedi, B., Maurice, N. M., Ciavatta, V. T., Lynn, K. S., Yuan, Z., Molina, S. A., Joo, M., Tyor, W. R., Goldberg, J. B., Koval, M., Hart, C. M., Sadikot, R. T. Peroxisome proliferator-activated receptor-γ agonists attenuate biofilm formation by Pseudomonas aeruginosa.

Soluble common gamma chain exacerbates COPD progress through the regulation of inflammatory T cell response in mice.

Cigarette smoking (CS) is a major cause of considerable morbidity and mortality by inducing lung cancer and COPD. COPD, a smoking-related disorder, is closely related to the alteration of immune system and inflammatory processes that are specifically mediated by T cells. Soluble common gamma chain (sγc) has recently been identified as a critical regulator of the development and differentiation of T cells. We examined the effects of sγc in a cigarette smoke extract (CSE) mouse model. The sγc level in CSE mice serum is significantly downregulated, and the cellularity of lymph node (LN) is systemically reduced in the CSE group. Overexpression of sγc enhances the cellularity and IFNγ production of CD8 T cells in LN and also enhances Th1 and Th17 differentiation of CD4 T cells in the respiratory tract. Mechanistically, the downregulation of sγc expression mediated by CSE is required to prevent excessive inflammatory T cell responses. Therefore, our data suggest that sγc may be one of the target molecules for the control of immunopathogenic progresses in COPD.