The PPARγ agonist, rosiglitazone, attenuates airway inflammation and remodeling via heme oxygenase-1 in murine model of asthma

Vincamine alleviates intrahepatic cholestasis in rats through modulation of NF-kB/PDGF/klf6/PPARγ and PI3K/Akt pathways

The defect in the hepatobiliary transport system results in an impairment of bile flow, leading to accumulation of toxic compounds with subsequent liver disorders. Vincamine, a plant indole alkaloid that is utilized as a dietary supplement, has been known for its promising pharmacological activities. For the first time, the present study was planned to estimate, at the molecular level, the potentiality of vincamine against alfa-naphthyl isothiocyanate (ANIT)-induced hepatic cholestasis. Liver function tests were analyzed. Hepatic activity of SOD and levels of GSH and MDA were assessed. Hepatic contents of bax, bcl2, NF-kB, PPARγ, catalase, heme-oxygenase-1, NTCP, and BSEP were evaluated using ELISA. mRNA levels of NF-kB, IL-1β, IL-6, TNFα, PDGF, klf6, PPARγ, and P53 were examined using qRT-PCR. PI3K, Akt and cleaved caspase-3 proteins were assessed using western blotting. Histopathological analyses were performed using hematoxylin & eosin staining. ANIT-induced hepatic cholestasis elevated liver function tests, including AST, ALT, GGT, ALP, and total bilirubin. ANIT reduced the protein expression of NTCP and BSEP hepatic transporters. It induced the expression of the inflammatory genes, TNFα, IL-6, IL-1β, and PDGF, and the expression of NF-kB at the genetic and protein level and suppressed the anti-inflammatory genes, klf6 and PPARγ. Also, antioxidant markers were reduced during ANIT induction such as GSH, SOD, catalase, heme-oxygenase-1 and PI3K/Akt pathway, while MDA levels were elevated. Furthermore, the expression of P53 gene, bax and cleaved caspase 3 proteins were activated, while bcl2 was inhibited. Also, the histopathological analysis showed degeneration of hepatocytes and inflammatory cellular infiltrates. However, vincamine treatment modulated all these markers. It improved liver function tests. It inhibited the expression of NF-kB, TNFα, IL-6, IL-1β and PDGF and activated the expression of klf6 and PPARγ. Furthermore, vincamine reduced MDA levels and induced GSH, SOD, catalase, heme-oxygenase-1 and PI3K/Akt pathway. Additionally, it inhibited expression of P53 gene, bax and cleaved caspase 3 proteins. More interestingly, vincamine showed better outcomes on the hepatic histopathological analysis and improved the alterations induced by ANIT. Vincamine alleviated hepatic dysfunction during ANIT-induced intrahepatic cholestasis through its anti-inflammatory and antioxidant efficacies by the modulation of NF-kB/PDGF/klf6/PPARγ and PI3K/Akt pathways.

Harnessing peroxisome proliferator-activated receptor γ agonists to induce Heme Oxygenase-1: a promising approach for pulmonary inflammatory disorders

The activation of peroxisome proliferator-activated receptor (PPAR)-γ has been extensively shown to attenuate inflammatory responses in conditions such as asthma, acute lung injury, and acute respiratory distress syndrome, as demonstrated in animal studies. However, the precise molecular mechanisms underlying these inhibitory effects remain largely unknown. The upregulation of heme oxygenase-1 (HO-1) has been shown to confer protective effects, including antioxidant, antiapoptotic, and immunomodulatory effects in vitro and in vivo. PPARγ is highly expressed not only in adipose tissues but also in various other tissues, including the pulmonary system. Thiazolidinediones (TZDs) are highly selective agonists for PPARγ and are used as antihyperglycemic medications. These observations suggest that PPARγ agonists could modulate metabolism and inflammation. Several studies have indicated that PPARγ agonists may serve as potential therapeutic candidates in inflammation-related diseases by upregulating HO-1, which in turn modulates inflammatory responses. In the respiratory system, exposure to external insults triggers the expression of inflammatory molecules, such as cytokines, chemokines, adhesion molecules, matrix metalloproteinases, and reactive oxygen species, leading to the development of pulmonary inflammatory diseases. Previous studies have demonstrated that the upregulation of HO-1 protects tissues and cells from external insults, indicating that the induction of HO-1 by PPARγ agonists could exert protective effects by inhibiting inflammatory signaling pathways and attenuating the development of pulmonary inflammatory diseases. However, the mechanisms underlying TZD-induced HO-1 expression are not well understood. This review aimed to elucidate the molecular mechanisms through which PPARγ agonists induce the expression of HO-1 and explore how they protect against inflammatory and oxidative responses.

Rosiglitazone-Mediated Activation of PPARγ Restores HO1 Expression in the Human Preeclamptic Placenta

BACKGROUND

Preeclampsia is a hypertensive disorder of pregnancy characterized by chronic placental ischemia and suppression of proangiogenic proteins, causing oxidative stress, hypertension, and maternal systemic organ damage. The transcription factor, PPARγ (peroxisome proliferator-activated receptor-γ) promotes healthy trophoblast differentiation but is dysregulated in the preeclampsia placenta. Our study identifies the beneficial impact of Rosiglitazone-mediated PPARγ-activation in the stressed preeclampsia placenta.

METHODS

We used first trimester placentas, preeclamptic and preterm control placentas, and human trophoblast cell lines to study PPARγ activation.

RESULTS

Induction of PPARγ activates cell growth and antioxidative stress pathways, including the gene, heme oxygenase 1 (Hmox1). Protein expression of both PPARγ and HO1 (heme oxygenase 1) are reduced in preeclamptic placentas, but Rosiglitazone restores HO1 signaling in a PPARγ-dependent manner.

CONCLUSIONS

Restoring disrupted pathways by PPARγ in preeclampsia offers a potential therapeutic pathway to reverse placental damage, extending pregnancy duration, and reduce maternal sequelae. Future research should aim to understand the full scope of impaired PPARγ signaling in the human placenta and focus on compounds for safe use during pregnancy to prevent severe perinatal morbidity and mortality.

Agnuside mitigates OVA-LPS induced perturbed lung homeostasis via modulating inflammatory, autophagy, apoptosis-fibrosis response and myeloid lineages in mice model of allergic asthma

Attributes of agnuside, a nontoxic, iridoid glycoside have been advocated for inflammatory disorders. However, information on its efficacy in alleviating allergic asthma largely remain ambiguous and yet to be deciphered. Present study aimed to assess efficacy of agnuside in targeting vicious circle of oxi-inflammation, autophagy and fibrosis, together with investigating its underlying molecular mechanism during OVA-LPS induced allergic asthma. Results revealed that agnuside showed prophylactic effect in assuaging asthmatic lung architecture impairment (p ≤ 0.01) as indicated by suppression of inflammatory cell infiltration, congestion, fibrosis, airway remodeling and alveolar collapse in OVA-LPS sensitized group. Decreased expression level (p ≤ 0.05) of allergic inflammatory mediators such as IgE, Th1/Th2, IL-4/IFN-γ, IL-4/IL-10, chemokines, endopeptidases and TGF-β, Smad2/4, Caspase9/3, connexin 43/50 observed in agnuside treatments. Analysis of redox molecular signaling cascade and autophagic proteins revealed concurrent upregulation in p-NF-κB, p-PI3K, p-Akt, p-p38, p-Stat3 activation, GATA3, LC3B expression and reduction in Bcl2/Bax, Beclin1 and p62 expression in sensitized mice (p ≤ 0.05) which were intensely counteracted by administration of agnuside. Suppression in myeloid cells activation and augmentation (p ≤ 0.001) of Tregs established modulatory attribute of agnuside for innate and adaptive immune response during allergic asthma. Collectively, these outcomes confer prophylactic attribute of agnuside and signify it as promising strategy to thwart allergic asthma.

Emodin attenuates severe acute pancreatitis-associated acute lung injury by suppressing pancreatic exosome-mediated alveolar macrophage activation

Severe acute pancreatitis-associated acute lung injury (SAP-ALI) is a serious disease associated with high mortality. Emodin has been applied to alleviate SAP-ALI; however, the mechanism remains unclear. We report that the therapeutic role of emodin in attenuating SAP-ALI is partly dependent on an exosomal mechanism. SAP rats had increased levels of plasma exosomes with altered protein contents compared to the sham rats. These infused plasma exosomes tended to accumulate in the lungs and promoted the hyper-activation of alveolar macrophages and inflammatory damage. Conversely, emodin treatment decreased the plasma/pancreatic exosome levels in the SAP rats. Emodin-primed exosomes showed less pro-inflammatory effects in alveolar macrophages and lung tissues than SAP exosomes. In detail, emodin-primed exosomes suppressed the NF-κB pathway to reduce the activation of alveolar macrophage and ameliorate lung inflammation by regulating PPARγ pathway, while these effects were amplified/abolished by PPARγ agonist/antagonist. Blockage of pancreatic acinar cell exosome biogenesis also exhibited suppression of alveolar macrophage activation and reduction of lung inflammation. This study suggests a vital role of exosomes in participating inflammation-associated organ-injury, and indicates emodin can attenuate SAP-ALI by reducing the pancreatic exosome-mediated alveolar macrophage activation.

New Oxazolidines Inhibit the Secretion of IFN-γ and IL-17 by PBMCS from Moderate to Severe Asthmatic Patients

BACKGROUND

Moderate to severe asthma could be induced by diverse proinflammatory cytokines, as IL-17 and IFN-γ, which are also related to treatment resistance and airway hyperresponsiveness. Oxazolidines emerged as a novel approach for asthma treatment, since some chemical peculiarities were suggested by previous studies.

OBJECTIVE

The present study aimed to evaluate the IL-17A and IFN-γ modulatory effect of two new oxazolidine derivatives (LPSF/NB-12 and -13) on mononucleated cells of patients with moderate and severe asthma.

METHODS

The study first looked at potential targets for oxazolidine derivatives using SWISS-ADME. After the synthesis of the compounds, cytotoxicity and cytokine levels were analyzed.

RESULTS

We demonstrated that LPSF/NB-12 and -13 reduced IFN-γ and IL-17 production in peripheral blood mononucleated cells from asthmatic patients in a concentrated manner. Our in silico analysis showed the neurokinin-1 receptor as a common target for both compounds, which is responsible for diverse proinflammatory effects of moderate and severe asthma.

CONCLUSION

The work demonstrated a novel approach against asthma, which deserves further studies of its mechanisms of action.

Chinese Herbs and Repurposing Old Drugs as Therapeutic Agents in the Regulation of Oxidative Stress and Inflammation in Pulmonary Diseases

Several pro-inflammatory factors and proteins have been characterized that are involved in the pathogenesis of inflammatory diseases, including acute respiratory distress syndrome, chronic obstructive pulmonary disease, and asthma, induced by oxidative stress, cytokines, bacterial toxins, and viruses. Reactive oxygen species (ROS) act as secondary messengers and are products of normal cellular metabolism. Under physiological conditions, ROS protect cells against oxidative stress through the maintenance of cellular redox homeostasis, which is important for proliferation, viability, cell activation, and organ function. However, overproduction of ROS is most frequently due to excessive stimulation of either the mitochondrial electron transport chain and xanthine oxidase or reduced nicotinamide adenine dinucleotide phosphate (NADPH) by pro-inflammatory cytokines, such as interleukin-1β and tumor necrosis factor α. NADPH oxidase activation and ROS overproduction could further induce numerous inflammatory target proteins that are potentially mediated via Nox/ROS-related transcription factors triggered by various intracellular signaling pathways. Thus, oxidative stress is considered important in pulmonary inflammatory processes. Previous studies have demonstrated that redox signals can induce pulmonary inflammatory diseases. Thus, therapeutic strategies directly targeting oxidative stress may be effective for pulmonary inflammatory diseases. Therefore, drugs with anti-inflammatory and anti-oxidative properties may be beneficial to these diseases. Recent studies have suggested that traditional Chinese medicines, statins, and peroxisome proliferation-activated receptor agonists could modulate inflammation-related signaling processes and may be beneficial for pulmonary inflammatory diseases. In particular, several herbal medicines have attracted attention for the management of pulmonary inflammatory diseases. Therefore, we reviewed the pharmacological effects of these drugs to dissect how they induce host defense mechanisms against oxidative injury to combat pulmonary inflammation. Moreover, the cytotoxicity of oxidative stress and apoptotic cell death can be protected via the induction of HO-1 by these drugs. The main objective of this review is to focus on Chinese herbs and old drugs to develop anti-inflammatory drugs able to induce HO-1 expression for the management of pulmonary inflammatory diseases.

Biflavonoid-rich fraction from Daphne pseudomezereum var. koreana Hamaya exerts anti-inflammatory effect in an experimental animal model of allergic asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Daphne pseudomezereum var. koreana Hamaya is distributed in the Gangwon-do of South Korea and is traditionally used to treat chronic inflammatory diseases, including rheumatoid arthritis.

AIM OF THE STUDY

We investigated the anti-inflammatory effect of biflavonoid-rich fraction (BF) obtained from an extract of D. pseudomezereum leaves on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and mouse model of ovalbumin (OVA)-induced allergic asthma.

MATERIALS AND METHODS

Neochamaejasmin B (NB) and chamaejasmin D (CD) were spectroscopically characterized as major components of BF obtained from the leaves of D. pseudomezereum. RAW264.7 cells pretreated with NB, CD and BF and activated by LPS (500 ng/ml) were used to assess the anti-inflammatory effects of these materials in vitro. To evaluate the protective effect of BF on allergic asthma, female BALB/c mice were sensitized to OVA by intraperitoneal (i.p.) injection and treated with BF by oral administration (15 or 30 mg/kg).

RESULTS

Pretreatment with BF inhibited LPS-stimulated nitric oxide (NO), TNF-α and IL-6, and led to upregulation of heme oxygenase-1 (HO-1) in RAW264.7 macrophages. Orally administered BF significantly inhibited the recruitment of eosinophils and the production of IL-5, IL-6, IL-13 and MCP-1 as judged by the analysis of BALF from OVA-induced asthma animal model. BF also decreased the levels of IgE in the serum of asthmatic mice. BF suppressed the influx of inflammatory cells into nearby airways and the hypersecretion of mucus by the airway epithelium of asthmatic mice. In addition, the increase in Penh in asthmatic mice was reduced by BF administration. Furthermore, BF led to Nrf2 activation and HO-1 induction in the lungs of mice.

CONCLUSIONS

These data have shown the anti-asthmatic effects of BF, and therefore we expect that BF may be a potential candidate as a natural drug/nutraceutical for the prevention and treatment of allergic asthma.

RNA-Seq Expression Analysis of Chronic Asthmatic Mice with Bu-Shen-Yi-Qi Formula Treatment and Prediction of Regulated Gene Targets of Anti-Airway Remodeling

Airway remodeling is one of the typical pathological characteristics of asthma, while the structural changes of the airways in asthma are complex, which impedes the development of novel asthma targeted therapy. Our previous study had shown that Bu-Shen-Yi-Qi formula (BSYQF) could ameliorate airway remodeling in chronic asthmatic mice by modulating airway inflammation and oxidative stress in the lung. In this study, we analysed the lung transcriptome of control mice and asthmatic mouse model with/without BSYQF treatment. Using RNA-sequencing (RNA-seq) analysis, we found that 264/1746 (15.1%) of transcripts showing abnormal expression in asthmatic mice were reverted back to completely or partially normal levels by BSYQF treatment. Additionally, based on previous results, we identified 21 differential expression genes (DEGs) with fold changes (FC) > (±) 2.0 related to inflammatory, oxidative stress, mitochondria, PI3K/AKT, and MAPK signal pathways which may play important roles in the mechanism of the anti-remodeling effect of BSYQF treatment. Through inputting 21 DEGs into the IPA database to construct a gene network, we inferred Adipoq, SPP1, and TNC which were located at critical nodes in the network may be key regulators of BSYQF's anti-remodeling effect. In addition, the quantitative real-time polymerase chain reaction (qRT-PCR) result for the selected four DEGs matched those of the RNA-seq analysis. Our results provide a preliminary clue to the molecular mechanism of the anti-remodeling effect of BSYQF in asthma.

Biochanin A Mitigates Atherosclerosis by Inhibiting Lipid Accumulation and Inflammatory Response

Biochanin A (BCA), a dietary isoflavone extracted from red clover and cabbage, has been shown to antagonize hypertension and myocardial ischemia/reperfusion injury. However, very little is known about its role in atherogenesis. The aim of this study was to observe the effects of BCA on atherosclerosis and explore the underlying mechanisms. Our results showed that administration of BCA promoted reverse cholesterol transport (RCT), improved plasma lipid profile, and decreased serum proinflammatory cytokine levels and atherosclerotic lesion area in apoE^-/- mice fed a Western diet. In THP-1 macrophage-derived foam cells, treatment with BCA upregulated ATP-binding cassette (ABC) transporter A1 (ABCA1) and ABCG1 expression and facilitated subsequent cholesterol efflux and diminished intracellular cholesterol contents by activating the peroxisome proliferator-activated receptor γ (PPARγ)/liver X receptor α (LXRα) and PPARγ/heme oxygenase 1 (HO-1) pathways. BCA also activated these two signaling pathways to inhibit the secretion of proinflammatory cytokines. Taken together, these findings suggest that BCA is protective against atherosclerosis by inhibiting lipid accumulation and inflammatory response through the PPARγ/LXRα and PPARγ/HO-1 pathways. BCA may be an attractive drug for the prevention and treatment of atherosclerotic cardiovascular disease.

Imbalanced serum levels of resolvin E1 (RvE1) and leukotriene B4 (LTB4) in patients with allergic rhinitis

Timely and successful resolution of acute inflammation plays a crucial role in preventing the development of chronic airway inflammation in allergic rhinitis (AR). This study intends to assess the serum levels of pro-inflammatory leukotriene B4 (LTB4), anti-inflammatory mediators, including resolvin E1 (RvE1), RvD1, IL-10, and TGF-β, besides mRNA expression level of G-protein coupled receptor 120 (GPR120) and peroxisome proliferator-activated receptor-γ (PPAR-γ) receptors in peripheral blood leukocytes of AR patients. Thirty-seven AR patients and thirty age- and gender-matched healthy subjects were enrolled in this study. The serum levels of LTB4, RvE1, RvD1, IL-10, and TGF-β were measured using enzyme-linked immunosorbent assay (ELISA) technique, and the mRNA expression level of GPR120 and PPAR-γ was assessed by the real-time PCR method. The serum levels of RvE1 and LTB4 were significantly higher in patients with AR than in healthy subjects (P < 0.01 and P < 0.0001, respectively). However, a significantly lower ratio of RvE1 and RvD1 to LTB4 was found in patients with AR relative to healthy subjects (P < 0.05 and P < 0.0001, respectively). Likewise, the serum levels of both IL-10 and TGF-β cytokines were significantly reduced in patients with AR compared to healthy subjects (P < 0.01 and P < 0.0001, respectively). Furthermore, the mRNA expression of PPAR-γ was significantly lower in patients with AR than in healthy subjects (P < 0.05). Our findings indicate that imbalanced pro-resolving lipid mediator RvE1 and pro-inflammatory LTB4 might contribute to the defective airway inflammation-resolution and subsequent progression toward chronic inflammation in AR patients.

Inhibition of NADPH Oxidase-Derived Reactive Oxygen Species Decreases Expression of Inflammatory Cytokines in A549 Cells

Various experimental models strongly support the hypothesis that airway inflammation can be caused by oxidative stress. Inflammatory airway diseases like asthma and COPD are characterized by higher levels of ROS and inflammatory cytokines. One of the sources of ROS is NADPH oxidase. Therefore, the aim of the study was to investigate influence of NADPH oxidase inhibition on the expression of IL-6, IL-8, TNF, TSLP, CD59, and PPAR-γ in vitro. A549 cells were incubated with apocynin in three concentrations (0.5 mg/ml, 1 mg/ml, and 3 mg/ml). Cells were trypsinized and RNA isolated after 1 h, 2 h, and 4 h of apocynin incubation at each concentration. Afterwards, reverse transcription was performed to evaluate mRNA expression using real-time PCR. The time-response and dose-response study showed that apocynin significantly influenced the relative expression of chosen genes (IL-6, IL-8, TNF, PPAR-γ, TSLP, and CD59). Apocynin decreased the mRNA expression of TNF-α at all concentrations used, and of IL-6 at concentrations of 1 and 3 mg/ml (p < 0.05). TSLP mRNA expression was also reduced by apocynin after 1 h and 2 h, and CD59 mRNA after 1 h, but only at the highest concentration. The expression of PPAR-γ was reduced after apocynin in the highest concentrations only (p < 0.05). The results might suggest that proinflammatory agents’ expression levels are strongly connected to the presence of oxidative stress generated by NADPH oxidase and this might be at least partially eliminated by anti-oxidative action. Apocynin, as an effective inhibitor of NADPH oxidase, seems to be useful in potential anti-oxidative and anti-inflammatory therapy.

Mechanistic investigation of PPARγ-facilitated anti-asthmatic effects of Galangin (Norizalpinin): Insights from in silico and in vivo analyses

Peroxisome proliferator-activated receptor gamma (PPARγ) is a multifaceted ligand-activated transcription factor that regulates inflammatory responses in asthma pathophysiology. The present study corroborates PPARγ-mediated anti-asthmatic action of the flavonoid, galangin (norizalpinin). In silico molecular interactions reveal that galangin formed three H-bonds (Glu291, Leu340 and Ser342) and a π-sigma bond (Arg288) with PPARγ, contributing to the binding affinity and stability of the complex. In vivo studies explore the role of galangin as a propitious PPARγ agonist in mitigating airway inflammation, thereby excluding ligand-independent action of PPARγ. Accordingly, oral administration of galangin significantly ameliorated airway hyperresponsiveness, inflammation and goblet cell hyperplasia by the suppression of IL-4, 5, 13, 17, TNF-α, NO, ROS, EPO, IgE and increase of IFN-γ in ovalbumin-induced allergic asthma model. PPARγ expression (mRNA and protein) studies were performed to elucidate a possible mechanism by which galangin modulates. Furthermore, to eliminate PPARγ-independent effects of galangin, a specific PPARγ antagonist (GW9662) was administered, which dramatically reversed the effects of galangin on PPARγ up-regulation, confirming the pleiotropic role of galangin as a PPARγ agonist in asthma therapeutics. Taken together, our findings communicate that PPARγ plays as a master regulator in the anti-asthmatic action of galangin.

Integrative analysis of the contribution of mRNAs and long non‑coding RNAs to the pathogenesis of asthma

Asthma, a common but poorly controlled disease, is one of the most serious health problems worldwide; however, the mechanisms underlying the development of asthma remain unknown. Long non-coding RNAs (lncRNAs) and mRNAs serve important roles in the initiation and progression of various diseases. The present study aimed to investigate the role of differentially expressed lncRNAs and mRNAs associated with asthma. Differentially expressed lncRNAs and mRNAs were screened between the expression data of 62 patients with asthma and 43 healthy controls. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to investigate the biological functions and pathways associated with the lncRNAs and mRNAs identified. Protein-protein interaction (PPI) networks were subsequently generated. In addition, lncRNA-mRNA weighted co-expression networks were obtained. In total, 159 differentially expressed lncRNAs and 1,261 mRNAs were identified. GO and KEGG analyses revealed that differentially expressed mRNAs regulated asthma by participating in the ‘vascular endothelial (VEGF) signaling pathway’, ‘oxidative phosphorylation’, ‘Fc ε RI signaling pathway’, ‘amino sugar and nucleotide sugar metabolism’, ‘histidine metabolism’, ‘β-alanine metabolism’ and ‘extracellular matrix-receptor interaction’ (P<0.05). Furthermore, protein kinase B 1 had the highest connectivity degree in the PPI network, and was significantly enriched in the ‘VEGF signaling pathway’ and ‘Fc ε RI signaling pathway’. A total of 8 lncRNAs in the lncRNA-mRNA co-expression network were reported to interact with 52 differentially expressed genes, which were enriched in asthma-associated GO and KEGG pathways. The results obtained in the present study may provide insight into the profile of differentially expressed lncRNAs associated with asthma. The identification of a cluster of dysregulated lncRNAs and mRNAs may serve as a potential therapeutic strategy to reverse the progression of asthma.

Curcumin Attenuates Asthmatic Airway Inflammation and Mucus Hypersecretion Involving a PPARγ-Dependent NF-κB Signaling Pathway In Vivo and In Vitro

Asthma is characterized by airway inflammation and mucus hypersecretion. Curcumin possessed a potent anti-inflammatory property involved in the PPARγ-dependent NF-κB signaling pathway. Then, the aim of the current study was to explore the value of curcumin in asthmatic airway inflammation and mucus secretion and its underlying mechanism. In vivo, mice were sensitized and challenged by ovalbumin (OVA) to induce chronic asthma. Airway inflammation and mucus secretion were analyzed. In vitro, BEAS-2B cells were obtained. MCP-1, MUC5AC, and PPARγ expression and the phosphorylation of NF-κB p65 and NF-κB p65 DNA-binding activity were measured in both the lungs and BEAS-2B cells. shRNA-PPARγ was used to knock down PPARγ expression. We found that OVA-induced airway inflammation and mucus hypersecretion in mice, OVA and IL-4-induced upregulation of MCP-1 and MUC5AC, suppression of PPARγ, and activation and translocation of NF-κB p65 were notably improved by curcumin both in vivo and in vitro. Our data also showed that these effects of curcumin were significantly abrogated by shRNA-PPARγ. Taken together, our results indicate that curcumin attenuated OVA-induced airway inflammation and mucus hypersecretion in mice and suppressed OVA- and IL-4-induced upregulation of MCP-1 and MUC5AC both in vivo and in vitro, most likely through a PPARγ-dependent NF-κB signaling pathway.

Physalis peruviana L. inhibits ovalbumin‑induced airway inflammation by attenuating the activation of NF‑κB and inflammatory molecules

Physalis peruviana L. (PP) is well known for its various properties, including its antioxidant property. In our previous study, the protective effects of PP against cigarette smoke‑induced airway inflammation were confirmed. The purpose of the present study was to evaluate the anti‑inflammatory effect of PP against ovalbumin (OVA)‑induced airway inflammation. Treatment with PP inhibited the numbers of eosinophils and the levels of inflammatory cytokines, including interleukin (IL)‑4, IL‑5 and IL‑13, in the bronchoalveolar lavage fluid (BALF) of animal models with OVA‑induced allergic asthma. PP also significantly decreased the production of total immunoglobulin E in the serum. Lung sections stained with hematoxylin and eosin revealed that the influx of inflammatory cells was decreased in the lungs of mice treated with PP compared with cells in the OVA group. The increased expression levels of monocyte chemoattractant protein‑1 (MCP‑1) and T cell marker KEN‑5 were also reduced following PP treatment in the lung tissues compared with those in the OVA group. The PAS staining results showed that PP attenuated the overproduction of mucus in the lung. Additionally, western blot analysis revealed that PP significantly downregulated the activation of nuclear factor‑κB/p38 mitogen‑activated protein kinase/c‑Jun N‑terminal kinase, and upregulated the expression of heme oxgenase‑1 in the lungs. In an in vitro experiment, PP effectively reduced the levels of LPS‑stimulated MCP‑1 in a concentration‑dependent manner. Taken together, these results indicate that PP has considerable potential in the treatment of allergic asthma.

Diabetes and Lung Disease: A Neglected Relationship

BACKGROUND

Diabetes mellitus is a systemic disorder associated with inflammation and oxidative stress which may target many organs such as the kidney, retina, and the vascular system. The pathophysiology, mechanisms, and consequences of diabetes on these organs have been studied widely. However, no work has been done on the concept of the lung as a target organ for diabetes and its implications for lung diseases.

AIM

In this review, we aimed to investigate the effects of diabetes and hypoglycemic agent on lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, pulmonary hypertension, and lung cancer. We also reviewed the potential mechanisms by which these effects may affect lung disease patients.

RESULTS

Our results suggest that diabetes can affect the severity and clinical course of several lung diseases.

CONCLUSIONS

Although the diabetes-lung association is epidemiologically and clinically well-established, especially in asthma, the underlying mechanism and pathophysiology are not been fully understood. Several mechanisms have been suggested, mainly associated with the pro-inflammatory and proliferative properties of diabetes, but also in relation to micro- and macrovascular effects of diabetes on the pulmonary vasculature. Also, hypoglycemic drugs may influence lung diseases in different ways. For example, metformin was considered a potential therapeutic agent in lung diseases, while insulin was shown to exacerbate lung diseases; this suggests that their effects extend beyond their hypoglycemic properties.

Heme oxygenase-1 as a potential therapeutic target in rheumatic diseases

BACKGROUND

Heme oxygenase-1 (HO-1), a cellular stress protein, serves a vital metabolic function as the rate-limiting enzyme in the degradation of heme to generate carbon monoxide (CO), iron, and biliverdin (BR). HO-1 may function as one of the most momentous factors of cell adaptation to oxidase stress, as well as a regulator of inflammatory signaling programs through the generation of its biologically active end products. Intensive investigation is now focusing on the potential function of HO-1 in inflammatory disorders, among which rheumatic diseases are one of the principal issues.

METHODS

"Heme oxygenase-1", "rheumatic diseases"; "lupus", "rheumatic arthritis", "osteoarthritis" and "oxidative stress" were used as key words for searching in Pubmed and Google scholar database.

RESULTS

Collected information from the related articles revealed the important role of pathogenesis and therapeutic potential of HO-1 in rheumatic diseases. Conclusions and discussions HO-1 has potential as a target for the treatment of rheumatic diseases due to its characteristic anti-inflammatory and anti-oxidative role. However, it is essential to monitor the HO-1 expression during particular stage of the disorders, and levels of HO-1 in different tissues and organs should be further confirmed in order to correlate it with clinical symptoms and other hallmarks of rheumatic diseases.

Immunoresolvents in asthma and allergic diseases: Review and update

Asthma and allergic diseases are inflammatory conditions developed by excessive reaction of the immune system against normally harmless environmental substances. Although acute inflammation is necessary to eradicate the damaging agents, shifting to chronic inflammation can be potentially detrimental. Essential fatty-acids-derived immunoresolvents, namely, lipoxins, resolvins, protectins, and maresins, are anti-inflammatory compounds that are believed to have protective and beneficial effects in inflammatory disorders, including asthma and allergies. Accordingly, impaired biosynthesis and defective production of immunoresolvents could be involved in the development of chronic inflammation. In this review, recent evidence on the anti-inflam]matory effects of immunoresolvents, their enzymatic biosynthesis routes, as well as their receptors are discussed.

Haem oxygenase-1 up-regulation by rosiglitazone via ROS-dependent Nrf2-antioxidant response elements axis or PPARγ attenuates LPS-mediated lung inflammation

BACKGROUND AND PURPOSE

Haem oxygenase-1 (HO-1) is induced by thiazolidinediones including rosiglitazone and exerts anti-inflammatory effects in various models. However, the molecular mechanisms underlying rosiglitazone-induced HO-1 expression remain largely unknown in human pulmonary alveolar epithelial cells (HPAEpiCs).

EXPERIMENTAL APPROACH

HO-1 expression was determined by real time-PCR, Western blotting and promoter reporter analyses. Signalling pathways were investigated using pharmacological inhibitors or specific siRNAs. Interactions between nuclear factor erythroid-2-related factor (Nrf2) and antioxidant response elements (ARE) binding site of the HO-1 promoter were investigated with chromatin immunoprecipitation assays.

KEY RESULTS

Up-regulation of HO-1 in HPAEpiCs or in mice by rosiglitazone blunted ICAM-1 expression and monocyte adhesion to HPAEpiCs challenged with LPS. Rosiglitazone-induced HO-1 expression was significantly attenuated by NADPH oxidase (NOX) inhibitors (apocynin and diphenyleneiodonium) or ROS scavenger (N-acetyl cysteine). The involvement of NOX activity and ROS generation in rosiglitazone-induced HO-1 expression was confirmed by transfection with p47phox or NOX2 siRNA. Moreover, pretreatment with the inhibitors of c-Src (c-Srci II), proline-rich tyrosine kinase 2 (Pyk2) (PF431396), Akt (Akti VIII) or PPARγ (GW9662) and transfection with siRNA of c-Src, Pyk2, Akt or PPARγ abolished the rosiglitazone-induced HO-1 expression in HPAEpiCs. Subsequently, Nrf2 was activated by phosphorylation of c-Src, Pyk2 and Akt, which turned on transcription of HO-1 gene by binding to AREs binding site and enhancing ARE promoter activity.

CONCLUSIONS AND IMPLICATIONS

Rosiglitazone induces HO-1 expression via either NOX/ROS/c-Src/Pyk2/Akt-dependent Nrf2 activation or PPARγ in HPAEpiCs and suppresses LPS-mediated inflammatory responses, suggesting that PPARγ agonists may be useful for protection against pulmonary inflammation.

Activation of peroxisome proliferation-activated receptor-γ inhibits transforming growth factor-β1-induced airway smooth muscle cell proliferation by suppressing Smad-miR-21 signaling

The aims of the current study were to examine the signaling mechanisms for transforming growth factor-β1 (TGF-β1)-induced rat airway smooth muscle cell (ASMC) proliferation and to determine the effect of activation of peroxisome proliferation-activated receptor-γ (PPAR-γ) on TGF-β1-induced rat ASMC proliferation and its underlying mechanisms. TGF-β1 upregulated microRNA 21 (miR-21) expression by activating Smad2/3, and this in turn downregulated forkhead box O1 (FOXO1) mRNA expression. In addition, TGF-β1-Smad-miR-21 signaling also downregulated phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression and thus de-repressed the PI3K-Akt pathway. Depletion of PTEN reduced the nuclear FOXO1 protein level without affecting its mRNA level. Inhibition of the PI3K-Akt pathway or proteasome function reversed PTEN knockdown-induced nuclear FOXO1 protein reduction. Our study further showed that loss of FOXO1 increased cyclin D1 expression, leading to rat ASMC proliferation. Preincubation of rat ASMCs with pioglitazone, a PPAR-γ activator, blocked TGF-β1-induced activation of Smad2/3 and its downstream targets changes of miR-21, PTEN, Akt, FOXO1, and cyclin D1, resulting in the inhibition of rat ASMC proliferation. Our study suggests that the activation of PPAR-γ inhibits rat ASMC proliferation by suppressing Smad-miR-21 signaling and therefore has a potential value in the prevention and treatment of asthma by negatively modulating airway remodeling.

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.

Inhibition of transient receptor potential melastatin 8 alleviates airway inflammation and remodeling in a murine model of asthma with cold air stimulus

Cold air stimulus is an important environmental factor that exacerbates asthma. At the molecular level, the transient receptor potential melastatin 8 (TRPM8) plays a crucial part in cold detection. The roles of TRPM8 in airway inflammation and remodeling in a murine model of asthma with cold stimulus and the related molecular mechanism are largely unknown. In this study, C57BL/6 mice were randomly divided into four groups: phosphate-buffered saline control group (control), ovalbumin (OVA)-induced asthma group (OVA), OVA with cold air stimulus group (OVA+cold), and OVA+cold+shTRPM8 (TRPM8 short hairpin RNA) group. We showed that cold air stimulus-induced TRPM8 upregulation in the OVA+cold group. Moreover, TRPM8 knockdown significantly attenuated cold-induced inflammation and infiltration, decreased levels of immunoglobulin E, restored the Th1/Th2 balance, and reduced inflammatory cell accumulation and airway remodeling. Furthermore, we demonstrated that TRPM8 knockdown dramatically inhibited mitogen-activated protein kinase and nuclear factor-κB pathways. Collectively, these results revealed that cold air stimulus induced an airway inflammatory response and remodeling by increasing TRPM8 expression and that downregulation of TRPM8 alleviated these responses.

Heme oxygenase-1 induction by rosiglitazone via PKCα/AMPKα/p38 MAPKα/SIRT1/PPARγ pathway suppresses lipopolysaccharide-mediated pulmonary inflammation

HO-1 (heme oxygenase-1), an antioxidant enzyme, induced by rosiglitazone (PPAR ligands) can be a potential treatment of inflammation. However, the mechanisms of rosiglitazone-induced HO-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain largely unknown. In this study, we found that upregulation of HO-1 in vitro or in vivo by rosiglitazone attenuated VCAM-1 gene expression and monocyte adhesion to HPAEpiCs challenged with lipopolysaccharide (LPS). The inhibitory effects of rosiglitazone on LPS-mediated responses were reversed by transfection with HO-1 siRNA. LPS-induced VCAM-1 expression was mediated through NF-κB activation which was attenuated by rosiglitazone via suppressing p65 activation and translocation into the nucleus. Moreover, pretreatment with the inhibitor of PKCs (H7), PKCα (Gö6976), AMPKα (Compound C), p38 MAPKα (p38i VIII), SIRT1 (Sirtinol), or PPARγ (T0070907) and transfection with siRNA of PKCα, AMPKα, p38 MAPKα, SIRT1, or PPARγ abolished the rosiglitazone-induced HO-1 expression in HPAEpiCs. Further studies indicated that rosiglitazone stimulated SIRT1 deacetylase leading to PGC1α translocation from the cytosol into the nucleus, promoting fragmentation of NCoR and phosphorylation of PPARγ. Subsequently, PPARγ was activated by phosphorylation of PKCα, AMPKα, p38 MAPKα, and SIRT1, which turned on transcription of HO-1 gene by binding to PPAR response element (PPRE) and enhancing PPARγ promoter activity. These results suggested that rosiglitazone-induced HO-1 expression is mediated through PKCα/AMPKα/p38 MAPKα/SIRT1-dependent deacetylation of Ac-PGC1α and fragmentation of NCoR/PPARγ activation in HPAEpiCs. Up-regulation of HO-1 protected against the inflammatory responses triggered by LPS, at least in part, through attenuation of NF-κB.

Protective role of peroxisome proliferator-activated receptor α agonists in skin barrier and inflammation

Peroxisome proliferator-activated receptor α (PPARα) is one of the three isoforms of PPARs, which are ligand-activated nuclear transcription factors. PPARα is highly expressed in liver and its agonists are widely used to treat hyperlipidemia. Epidermal keratinocytes express all three isoforms (α, β/δ, and γ) of PPARs and PPARα is particularly important for regulating the epidermal barrier and inflammation. Agonistic ligation of PPARα protects the epidermal barrier function and inhibits the inflammatory response in dermatitis. In this review, we summarize recent topics on the role of PPARα in skin biology and discuss the potential use of topical PPARα agonists for treating atopic dermatitis and other eczemas.

The Toxicological Mechanisms of Environmental Soot (Black Carbon) and Carbon Black: Focus on Oxidative Stress and Inflammatory Pathways

The environmental soot and carbon blacks (CBs) cause many diseases in humans, but their underlying mechanisms of toxicity are still poorly understood. Both are formed after the incomplete combustion of hydrocarbons but differ in their constituents and percent carbon contents. For the first time, “Sir Percival Pott” described soot as a carcinogen, which was subsequently confirmed by many others. The existing data suggest three main types of diseases due to soot and CB exposures: cancer, respiratory diseases, and cardiovascular dysfunctions. Experimental models revealed the involvement of oxidative stress, DNA methylation, formation of DNA adducts, and Aryl hydrocarbon receptor activation as the key mechanisms of soot- and CB-induced cancers. Metals including Si, Fe, Mn, Ti, and Co in soot also contribute in the reactive oxygen species (ROS)-mediated DNA damage. Mechanistically, ROS-induced DNA damage is further enhanced by eosinophils and neutrophils via halide (Cl⁻ and Br⁻) dependent DNA adducts formation. The activation of pulmonary dendritic cells, T helper type 2 cells, and mast cells is crucial mediators in the pathology of soot- or CB-induced respiratory disease. Polyunsaturated fatty acids (PUFAs) were also found to modulate T cells functions in respiratory diseases. Particularly, telomerase reverse transcriptase was found to play the critical role in soot- and CB-induced cardiovascular dysfunctions. In this review, we propose integrated mechanisms of soot- and CB-induced toxicity emphasizing the role of inflammatory mediators and oxidative stress. We also suggest use of antioxidants and PUFAs as protective strategies against soot- and CB-induced disorders.

Effect of PPARγ agonist (rosiglitazone) on the secretion of Th2 cytokine in asthma mice

OBJECTIVE

To explore the effect of PPARγ agonist (rosiglitazone) on the secretion of Th2 cytokines and the proportion of immune cell subsets in asthma mice.

METHODS

Ovalbumin (OVA)-sensitized mice were used to build asthma models. Those mice were divided into the normal control group, model group and rosiglitazone group. Differences of the changes in lung histopathology of mice in the three groups were observed through hematoxylin and eosin (HE) strain, and the numbers of the total cells, eosinophils and neutrophils in BALF of mice in the three groups were compared. ELISA and real-time PCR were employed to detect the protein levels of interleukin (IL)-5, IL-13, IL-4 and IL-10 and mRNA level, respectively. Flow cytometry number was implied to analyze the proportion of immune cell subsets in peripheral blood of mice.

RESULTS

Compared with the mice in the control group, and mice of the model group, the infiltration of inflammatory cells in BALF increased, bronchial smooth muscle became thickened, a large amount of collagen deposited, the secretion of Th2 cytokine increased significantly, the ratio of regulatory T cells (Treg) decreased, the ratio of T17 cells rose distinctly; while in mice of the rosiglitazone group, the changes of their lung histopathology were improved obviously, the number of infiltration of inflammatory cells declined, the thickened smooth muscle relieved, the deposition of collagen decreased, the secretion of Th2 cytokine was inhibited, the ratio of Treg went up, and the increased of the ratio of T17 cells was inhibited but still not return to normal level.

CONCLUSIONS

Rosiglitazone can regulate the proportion of Treg and Th17 cells and inhibit the secretion of Th2 cytokines, which inhibit the airway inflammatory response for asthma mice effectively.

Activation of Cold-Sensitive Channels TRPM8 and TRPA1 Inhibits the Proliferative Airway Smooth Muscle Cell Phenotype

PURPOSE

Airway smooth muscle cell (ASMC) phenotypic modulation is one of the key factors contributing to asthma. Temperature changes may induce asthma, and these changes are known to be related to the temperature-sensitive transient receptor potential channels (TS-TRPs). The present study was designed to investigate the cellular functions of cold-sensitive channels, TRPM8 and TRPA1, in the phenotypic modulation of ASMCs.

METHODS

A rat asthma model was constructed and the expression of TS-TRPs in ASM was tested. Using the agonists and antagonists for both TRPM8 and TRPA1, the effects of cold-sensitive channels on the phenotypic modulation of ASMCs were evaluated by measurement of contractile protein expression and cell proliferation and migration. Signaling pathways and matrix metalloproteinase-2 (MMP-2) activity were assayed with Western blotting and gelatin zymography.

RESULTS

TRPM8 and TRPA1 were decreased in the ASM of the rat asthma model. Icilin and menthol, agonists for TRPM8 and TRPA1, inhibited ASMC proliferation and migration induced by fetal bovine serum (FBS) or platelet-derived growth factor (PDGF). Moreover, icilin reversed the FBS-induced inhibition of the expression of contractile phenotype markers, smooth muscle α-actin, and SM22α. Icilin also antagonized the activation of p38 and MMP-2 and the repression of p21 caused by FBS.

CONCLUSIONS

Our findings show, for the first time, that the activation of TRPM8 and TRPA1 inhibits ASMC proliferative phenotype. These data suggest that TRPM8 and TRPA1 agonists may be promising new therapies for asthma.

Soshiho-tang water extract inhibits ovalbumin-induced airway inflammation via the regulation of heme oxygenase-1

Background

Soshiho-tang, known as Xio-hai-Hu-Tang in Chinese and Sho-Saiko-to in Japanese, has been widely used as a therapeutic agent. Its pharmacological effects include anti-inflammatory, antioxidant, antihepatic fibrosis, antitumor and immunomodulating activities. However, little is known regarding its effects on allergic asthma. Therefore, the aim of the present study was to investigate whether the Soshiho-tang water extract (SSTW) has antiasthmatic effects on airway inflammation in an ovalbumin (OVA)-induced mouse model.

Methods

BALB/c mice were used as a model of asthma after induction by sensitization and challenge with OVA. We measured change in eosinophils, other inflammatory cells, and T helper 2 (Th2)-type cytokines, such as interleukin (IL)-4, IL-5, IL-13, IL-17, IL-33, and chemokine (eotaxin) in bronchoalveolar lavage fluid (BALF), presence of total and OVA-specific immunoglobulin (Ig)E in plasma, and expression of mucus production and heme oxygenase (HO)-1 protein in lung tissue.

Results

Our results show that SSTW had a suppressive effect on eosinophil influx into BALF and decreased the levels of Th2-type cytokines. Moreover, SSTW exhibited a marked decrease in mucus hypersecretion, total and OVA-specific IgE levels, and significantly induced HO-1 protein expression.

Conclusions

These results suggest that SSTW may be used as a valuable therapeutic agent for treating various inflammatory diseases including allergic asthma.

Resveratrol potentiates the effect of dexamethasone in rat model of acute lung inflammation

Cigarette smoking is considered to be the main etiological factor in Chronic Obstructive Pulmonary Disease (COPD). In this study, we explored the potential of resveratrol, to reinstate the effectiveness of dexamethasone when administered as an adjunct in acute lung inflammation induced by cigarette smoke (CS) and lipopolysaccharide (LPS). CS and LPS instillation produced acute inflammatory response exhibited by increased leukocyte count, particularly neutrophils, total protein, MMP-9 activity, cytokines like TNF-α, IL-8 in bronchoalveolar lavage fluid (BALF) as well as elevated myeloperoxidase activity, and lipid peroxidation in lung. These alterations were not abated by dexamethasone (2.5mg/kg & 10mg/kg) and resveratrol (50mg/kg) alone. Combination of resveratrol (50mg/kg) and dexamethasone (2.5mg/kg) significantly reduced all inflammatory parameters. The protective effect of the combination was abolished when co-administered with sirtinol, a SIRT1 inhibitor. The results indicate that the combination therapy may serve as a potential approach for treating lung inflammatory conditions like COPD.