Curcumin Attenuates Airway Inflammation and Airway Remolding by Inhibiting NF-κB Signaling and COX-2 in Cigarette Smoke-Induced COPD Mice

Nanocurcumin: A Promising Candidate for Therapeutic Applications

Curcuma longa is an important medicinal plant and a spice in Asia. Curcumin (diferuloylmethane) is a hydrophobic bioactive ingredient found in a rhizome of the C. longa. It has drawn immense attention in recent years for its variety of biological and pharmacological action. However, its low water solubility, poor bioavailability, and rapid metabolism represent major drawbacks for its successful therapeutic applications. Hence, researchers have attempted to enhance the biological and pharmacological activity of curcumin and overcome its drawbacks by efficient delivery systems, particularly nanoencapsulation. Research efforts so far and data from the available literature have shown a satisfactory potential of nanorange formulations of curcumin (Nanocurcumin), it increases all the biological and pharmacological benefits of curcumin, which was not significantly possible earlier. For the synthesis of nanocurcumin, an array of techniques has been developed and each technique has its own advantages and individual characteristics. The two most popular and effective techniques are ionic gelation and antisolvent precipitation. So far, many curcumin nanoformulations have been developed to enhance curcumin delivery, thereby overcoming the low therapeutic effects. However, most of the nanoformulation of curcumin remained at the concept level evidence, thus, several questions and challenges still exist to recommend the nanocurcumin as a promising candidate for therapeutic applications. In this review, we discuss the different curcumin nanoformulation and nanocurcumin implications for different therapeutic applications as well as the status of ongoing clinical trials and patents. We also discuss the research gap and future research directions needed to propose curcumin as a promising therapeutic candidate.

Activation of the Nrf2/HO-1 pathway by curcumin inhibits oxidative stress in human nasal fibroblasts exposed to urban particulate matter

BACKGROUND

Particulate matter (PM) can cause various negative acute and chronic diseases of the respiratory system, including the upper airways. Curcumin has been reported to have anti-inflammatory and anti-oxidative effects; therefore, we investigated the effects of curcumin on nasal fibroblasts exposed to urban PM (UPM).

METHODS

Samples of inferior turbinate tissue were obtained from six patients. Flow cytometry was used to assess the levels of reactive oxygen species (ROS) following the treatment of nasal fibroblasts with UPM and/or curcumin. We evaluated the effects of UPM and/or curcumin on the expression of phosphorylated ERK, Nrf2, HO-1, and SOD2 in fibroblasts by Western blotting.

RESULTS

When UPM was applied to nasal fibroblasts, ROS production was significantly increased in a dose-dependent manner. UPM-exposed fibroblasts caused the activation of ERK to increase HO-1 expression and decrease SOD2 expression. Treatment with curcumin reduced the UPM-mediated increase in ROS; this decrease in ROS occurred in a dose-dependent manner. The UPM-induced activation of ERK was inhibited by curcumin. Nrf2 production was also promoted to increase the expression of HO-1 and SOD2 by curcumin.

CONCLUSION

Curcumin reduced ROS production caused by UPM in human nasal fibroblasts in a dose-dependent manner, suggesting that curcumin has anti-oxidative effects and may be useful in the treatment of nasal diseases caused by UPM, such as allergic and chronic rhinitis.

Triterpene Acids of Loquat Leaf Improve Inflammation in Cigarette Smoking Induced COPD by Regulating AMPK/Nrf2 and NFκB Pathways

Cigarette smoking (CS) is believed to be an important inducement in the pathological development of chronic obstructive pulmonary disease (COPD), a progressive lung disease. Loquat is an Asian evergreen tree commonly cultivated for its fruit. Its leaf has long been used as an important material for both functional and medicinal applications in the treatment of lung disease in China and Japan. As the principal functional components of loquat leaf, triterpene acids (TAs) have shown notable anti-inflammatory activity. However, their protective activity and underlying action of mechanism on CS-induced COPD inflammation are not yet well understood. In the present study, male C57BL/6 mice were challenged with CS for 12 weeks, and from the seventh week of CS exposure, mice were fed with TAs (50 and 100 mg/kg) for 6 weeks to figure out the therapeutic effect and molecular mechanism of TAs in CS-induced COPD inflammation. The results demonstrate that TA suppressed the lung histological changes in CS-exposed mice, as evidenced by the diminished generation of pro-inflammatory cytokines, including interleukin 1β (IL-1β), IL-2, IL-6, and tumor necrosis factor α (TNF-α). Moreover, TA treatment significantly inhibited the malondialdehyde (MDA) level and increased superoxide dismutase (SOD) activity. In addition, TAs increased the phosphorylation of AMP-activated protein kinase (AMPK) and nuclear factor erythroid-2-related factor-2 (Nrf2) expression level, while inhibiting phosphorylation of nuclear factor kappa B (NFκB) and inducible nitric oxide synthase (iNOS) expression in CS-induced COPD. In summary, our study reveals a protective effect and putative mechanism of TA action involving the inhibition of inflammation by regulating AMPK/Nrf2 and NFκB pathways. Our findings suggest that TAs could be considered as a promising functional material for treating CS-induced COPD.

Cigarette smoke-induced HMGB1 translocation and release contribute to migration and NF-κB activation through inducing autophagy in lung macrophages

High-mobility group box 1 (HMGB1) shows pro-inflammatory activity in various inflammatory diseases and has been found up-regulated in chronic obstructive pulmonary disease (COPD). Lung macrophages play an important role in airway inflammation and lung destruction in COPD, yet whether HMGB1 is involved in cigarette smoke (CS)-induced lung macrophage dysfunction is unknown. We sought to evaluate the intracellular localization and release of HMGB1 in lung macrophages from COPD patients and CS-exposed mice, and to investigate the role of HMGB1 in regulating autophagy in CS extract (CSE)-treated lung macrophages (MH-S cells). Our results showed that HMGB1 was highly expressed in lung tissues and sera of COPD patients and CS-exposed mice, along with predominantly cytoplasmic exporting from nuclei in lung macrophages. In vitro experiments revealed that CSE promoted the expression, nucleocytoplasmic translocation and release of HMGB1 partly via the nicotinic acetylcholine receptor (nAChR). Blockade of HMGB1 with chicken anti-HMGB1 polyclonal antibody (anti-HMGB1) or glycyrrhizin (Gly) attenuated the increase of LC3B-II and Beclin1, migration and p65 phosphorylation, suggesting the involvement of HMGB1 in autophagy, migration and NF-κB activation of lung macrophages. Hydroxychloroquine (CQ), an autophagy inhibitor, enhanced the increase of LC3B-II but not Beclin1 in CSE or rHMGB1-treated MH-S cells, and inhibition of autophagy by CQ and 3-methyladenine (3-MA) abrogated the migration and p65 phosphorylation of CSE-treated cells. These results indicate that CS-induced HMGB1 translocation and release contribute to migration and NF-κB activation through inducing autophagy in lung macrophages, providing novel evidence for HMGB1 as a potential target of intervention in COPD.

Cigarette smoke triggers inflammation mediated by autophagy in BEAS-2B cells

Cigarette smoking, as an individual consumption habit, is associated with a variety of related diseases. Exposure of cigarette smoke was reported to induce autophagy and inflammation in experimental animals and humans. However, the toxicity mechanism of cigarette smoke in organisms has not been entirely investigated. In this present study, we studied the role of autophagy played in the inflammation caused by cigarette smoke in human bronchial epithelial cells (BEAS-2B), as well as the role of the phosphatidylinositol 3-kinase (PI3K) signaling pathway and the mitogen-activated protein kinase (MAPK) signaling pathways underlying autophagy and inflammation. We found that cigarette smoke induced autophagy and inflammation in BEAS-2B, and the blockage of autophagy significantly reduced the release levels of IL-1β, IL-6 and IL-8 in BEAS-2B exposed to cigarette smoke for 24 h. Cigarette smoke downregulated the activity of PI3K/Akt/mTOR pathway and elevated the activity of MAPK pathways. Pretreatment of autophagic inhibitor could inhibit autophagy and the activity of JNK and p38 pathways. These results suggested that cigarette smoke-induced autophagy triggered inflammation through the activation of JNK and p38 pathways, which might contribute to understanding the adverse outcome pathways induced by cigarette smoke exposure and provide the information about the risk assessment of tobacco products.

[Curcumin suppresses invasiveness and migration of human glioma cells in vitro by inhibiting HDGF/β-catenin complex]

OBJECTIVE

To investigate the effect of curcumin on the invasion and migration of human glioma cells in vitro and explore the molecular mechanisms.

METHODS

MTT assay was used for screening the optimal curcumin concentrations. The effects of curcumin on the invasion and metastasis of human glioma cell lines U251 and LN229 were tested using Transwell assay, Boyden assay and wound-healing assays. The expression of the related proteins and their interactions were determined using Western blotting and coimmunoprecipitation assay.

RESULTS

Curcumin at the concentration of 20 μmol/L for 48 h was used as the optimal condition for subsequent cell treatment. In the two glioma cell lines, curcumin significantly suppressed the invasion and migration of the cells (P < 0.05) and lowered the expressions of hepatoma-derived growth factor (HDGF), Ncadherin, vimentin, Snail and Slug, but increased the expression of E-cadherin. Interference of HDGF in curcumin-treated glioma cells synergistically inhibited the epithelial-mesenchymal transition (EMT) signals, while overexpression of HDGF significantly reversed the inhibitory effect of curcumin on EMT; curcumin treatment could significantly reduce the binding of HDGF to β-catenin.

CONCLUSIONS

Curcumin suppresses EMT signal by reducing HDGF/β-catenin complex and thereby lowers the migration and invasion abilities of human glioma cells in vitro.

Ergosterol attenuates cigarette smoke extract-induced COPD by modulating inflammation, oxidative stress and apoptosis in vitro and in vivo

Cigarette smoke (CS) is the major cause of chronic obstructive pulmonary disease (COPD). CS heightens inflammation, oxidative stress and apoptosis. Ergosterol is the main bioactive ingredient in Cordyceps sinensis (C. sinensis), a traditional medicinal herb for various diseases. The objective of this work was to investigate the effects of ergosterol on anti-inflammatory and antioxidative stress as well as anti-apoptosis in a cigarette smoke extract (CSE)-induced COPD model both in vitro and in vivo Our results demonstrate that CSE induced inflammatory and oxidative stress and apoptosis with the involvement of the Bcl-2 family proteins via the nuclear factor kappa B (NF-κB)/p65 pathway in both 16HBE cells and Balb/c mice. CSE induced epithelial cell death and increased the expression of nitric oxide (NO), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), malondialdehyde (MAD) and the apoptosis-related proteins cleaved caspase 3/7/9 and cleaved-poly-(ADP)-ribose polymerase (PARP) both in vitro and in vivo, whereas decreased the levels of superoxide dismutase (SOD) and catalase (CAT). Treatment of 16HBE cells and Balb/c mice with ergosterol inhibited CSE-induced inflammatory and oxidative stress and apoptosis by inhibiting the activation of NF-κB/p65. Ergosterol suppressed apoptosis by inhibiting the expression of the apoptosis-related proteins both in vitro and in vivo Moreover, the usage of QNZ (an inhibitor of NF-κB) also partly demonstrated that NF-κB/p65 pathway was involved in the ergosterol protective progress. These results show that ergosterol suppressed COPD inflammatory and oxidative stress and apoptosis through the NF-κB/p65 pathway, suggesting that ergosterol may be partially responsible for the therapeutic effects of cultured C. sinensis on COPD patients.

Anti-inflammatory Action of Curcumin and Its Use in the Treatment of Lifestyle-related Diseases

Chronic inflammation plays a significant role in lifestyle-related diseases, such as cardiovascular diseases and obesity/impaired glucose tolerance. Curcumin is a natural extract that possesses numerous physiological properties, as indicated by its anti-inflammatory action. The mechanisms underlying these effects include the inhibition of nuclear factor-kappaB and Toll-like receptor 4-dependent signalling pathways and the activation of a peroxisome proliferator-activated receptor-gamma pathway. However, the bioavailability of curcumin is very low in humans. To resolve this issue, several drug delivery systems have been developed and a number of clinical trials have reported beneficial effects of curcumin in the management of inflammation-related diseases. It is expected that evidence regarding the clinical application of curcumin in lifestyle-related diseases associated with chronic inflammation will accumulate over time.

Curcumin inhibits cigarette smoke-induced inflammation via modulating the PPARγ-NF-κB signaling pathway

The PPARγ-NF-κB signaling pathway is involved in the anti-inflammatory effect of curcumin on cigarette smoke-induced COPD models.

Modulators of inflammation in Bronchopulmonary Dysplasia

Over 50 years after its first description, Bronchopulmonary Dysplasia (BPD) remains a devastating pulmonary complication in preterm infants with respiratory failure and develops in 30-50% of infants less than 1000-gram birth weight. It is thought to involve ventilator- and oxygen-induced damage to an immature lung that results in an inflammatory response and ends in aberrant lung development with dysregulated angiogenesis and alveolarization. Significant morbidity and mortality are associated with this most common chronic lung disease of childhood. Thus, any therapies that decrease the incidence or severity of this condition would have significant impact on morbidity, mortality, human costs, and healthcare expenditure. It is clear that an inflammatory response and the elaboration of growth factors and cytokines are associated with the development of BPD. Numerous approaches to control the inflammatory process leading to the development of BPD have been attempted. This review will examine the anti-inflammatory approaches that are established or hold promise for the prevention or treatment of BPD.

[Curcumin suppresses cigarette smoke extract-induced oxidative stress through PPARγ/ NF-κB pathway in human bronchial epithelial cells in vitro]

OBJECTIVE

To investigate the effect of curcumin against cigarette smoke extract (CSE)- induced oxidative stress in human bronchial epithelial cells and explore the underlying mechanism.

METHODS

Human bronchial epithelial cell line 16HBE was treated for 24 h with curcumin, CSE, CSE + curcumin, and CSE + curcumin with transfection by a short hairpin RNA targeting PPARγ (shPPARγ). MTT assay was used to observe the changes in the cell viability after the treatments. Quantitative real-time PCR was performed to detect the mRNA expressions of tumor necrosis factor-α (TNF-α), iNOS and PPARγ in the cells, and the protein expressions of iNOS, PPARγ and the phosphorylation of NF-κB p65 were detected using Western blotting.

RESULTS

The treatments did not cause significant changes in the cell viability. Exposure to CSE for 24 h significantly lowered PPARγ expression and increased TNF-α and iNOS expressions and phosphorylation of NF-κB p65 in the cells. The effects of CSE were significantly suppressed by curcumin, but transfection of the cells with shRNA-PPARγ obviously abrogated the suppressive effects of curcumin.

CONCLUSIONS

Curcumin suppresses CSE-induced oxidative stress and inflammation via the PPARγ/NF-κB signaling pathway in 16HBE cells, suggesting the potential of curcumin in the treatment of chronic obstructive pulmonary disease.