Protective role of andrographolide in bleomycin-induced pulmonary fibrosis in mice

ESL attenuates BLM-induced IPF in mice: Dual mediation of the TLR4/NF-κB and TGF-β1/PI3K/Akt/FOXO3a pathways

BACKGROUNDS

Idiopathic pulmonary fibrosis (IPF) is a persistent and advanced pulmonary ailment. The roles of innate immunity and adaptive immunity are pivotal in the evolution of IPF. An ill-adjusted interaction between epithelial cells and immune cells is responsible for initiating the epithelial-mesenchymal transition (EMT) process and sustaining chronic inflammation, thereby fostering fibrosis progression. The intricacy of IPF pathogenesis has hindered the availability of efficacious agents. Elephantopus scaber Linn. (ESL) is a canonical Chinese medicine with significant immunoregulatory effects, and its aqueous extract has been proven to attenuate IPF symptoms in bleomycin (BLM)-induced mice. However, the underlying mechanism through which ESL relieves IPF remains unclear.

AIM

To validate whether ESL reverses IPF by mediating the immune response and EMT.

METHODS

Ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) and UPLC were used to identify the components and determine the concentrations of the specific compounds in the ESL. Network pharmacology and molecular docking were applied to predict the potential mechanism underlying the anti-IPF effect of ESL. BLM-induced IPF mice were used to validate the anti-IPF effect of ESL, and lung tissue was collected to test putative pathways involved in inflammation and EMT via immunohistochemistry (ICH), real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting.

RESULTS

Sixty-one compounds were identified, and thirteen main ingredients were quantified in the ESL. In silico experiments predicted that the IPF-mediated reversal of adverse effects by ESL would be related to interruption of the Toll-like receptor 4 (TLR4)/nuclear factor-k-gene binding (NF-ĸB) inflammatory pathway and the transforming growth factor-beta l (TGF-β1)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/forkhead box O3 (FOXO3a) fibrosis pathway. In vivo experiments showed that ESL alleviates BLM-induced lung inflammation and fibrosis by reducing neutrophil aggregation and fibroblast foci, similar to the effects of the positive control drug pirfenidone (PFD). ESL markedly inhibited the transcription of TNF-α, IL-1β, and IL-6, which are downstream genes of the NF-κB signaling pathway. Furthermore, the protein levels of TLR4 and p-NF-κB were correspondingly inhibited in response to ESL treatment. Additionally, ESL reverses BLM-induced changes in the expression of EMT-related biological characteristic indicators (collagen I [COLIA1], E-cadherin, and alpha smooth muscle actin [α-SMA]) at the messenger ribonucleic acid (mRNA) level and markedly inhibits the expression of EMT-related upstream proteins (TGF-β1, p-PI3K, p-Akt, and p-FOXO3a).

CONCLUSION

Our research suggested that ESL attenuates BLM-induced IPF through mediating the EMT process via the TGF-β1/PI3K/Akt/FOXO3a signaling pathway and inhibiting inflammation through the TLR4/NF-κB signaling pathway, highlighting that ESL can serve as an immunoregulator for relieving the abnormal immune response and reversing the EMT in IPF.

Monomeric compounds from natural products for the treatment of pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is the end stage of lung injury and chronic lung diseases that results in diminished lung function, respiratory failure, and ultimately mortality. Despite extensive research, the pathogenesis of this disease remains elusive, and effective therapeutic options are currently limited, posing a significant clinical challenge. In addition, research on traditional Chinese medicine and naturopathic medicine is hampered by several complications due to complex composition and lack of reference compounds. Natural product monomers, possessing diverse biological activities and excellent safety profiles, have emerged as potential candidates for preventing and treating PF. The effective anti-PF ingredients identified can be generally divided into flavonoids, saponins, polysaccharides, and alkaloids. Specifically, these monomeric compounds can attenuate inflammatory response, oxidative stress, and other physiopathological processes of the lung through many signaling pathways. They also improve pulmonary factors. Additionally, they ameliorate epithelial-mesenchymal transition (EMT) and fibroblast-myofibroblast transdifferentiation (FMT) by regulating multiple signal amplifiers in the lungs, thereby mitigating PF. This review highlights the significant role of monomer compounds derived from natural products in reducing inflammation, oxidative stress, and inhibiting EMT process. The article provides comprehensive information and serves as a solid foundation for further exploration of new strategies to harness the potential of botanicals in the treatment of PF.

Effects of Waterpipe Smoke Exposure on Experimentally Induced Chronic Kidney Disease in Mice

Tobacco smoking is an independent risk factor in the onset of kidney disease. To date, there have been no reports on the influence of waterpipe smoke (WPS) in experimentally induced chronic kidney disease (CKD) models. We studied the effects and mechanisms of actions of WPS on a mouse model of adenine-induced CKD. Mice fed either a normal diet, or an adenine-added diet and were exposed to either air or WPS (30 min/day and 5 days/week) for four consecutive weeks. Plasma creatinine, urea and indoxyl sulfate increased and creatinine clearance decreased in adenine + WPS versus either WPS or adenine + saline groups. The urinary concentrations of kidney injury molecule-1 and adiponectin and the activities of neutrophil gelatinase-associated lipocalin and N-acetyl-β-D-glucosaminidase were augmented in adenine + WPS compared with either adenine + air or WPS groups. In the kidney tissue, several markers of oxidative stress and inflammation were higher in adenine + WPS than in either adenine + air or WPS groups. Compared with the controls, WPS inhalation in mice with CKD increased DNA damage, and urinary concentration of 8-hydroxy-2-deoxyguanosine. Furthermore, the expressions of nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) (ERK and p38) were elevated in the kidneys of adenine + WPS group, compared with the controls. Likewise, the kidneys of adenine + WPS group revealed more marked histological tubular injury, chronic inflammation and interstitial fibrosis. In conclusion, WPS inhalation aggravates kidney injury, oxidative stress, inflammation, DNA damage and fibrosis in mice with adenine-induced CKD, indicating that WPS exposure intensifies CKD. These effects were associated with a mechanism involving NF-κB, ERK and p38 activations.

Imrecoxib attenuates bleomycin-induced pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is an incurable chronic progressive disease with a low survival rate and ineffective therapeutic options. We examined the effects of imrecoxib, a nonsteroidal anti-inflammatory drug, on experimental pulmonary fibrosis. The mouse IPF model was established by intratracheal instillation of bleomycin. From Day 0 to Day 13, the mice were orally administered imrecoxib (100 mg/kg) and pirfenidone (200 mg/kg) daily, and from Day 7 to Day 13, the mice were orally administered pirfenidone and imrecoxib daily. The tissues were dissected on the 14th day. Mouse body weight was measured, and histopathological examination and hydroxyproline content analysis confirmed that the administration of imrecoxib exerted a similar effect to pirfenidone. Compared with bleomycin-induced mice, imrecoxib-treated mice showed significantly reduced inflammatory factor expression (IL-1 and TNF-α) and inflammatory cell numbers (macrophages, lymphocytes, and neutrophils) in BALF (bronchoalveolar lavage fluid). Our experiment tested the ability of imrecoxib to inhibit the signal pathway involved in gene expression induced by TGF-β1 in the NIH-3T3 cell line in vitro. Western blotting showed that imrecoxib (20 μM and 40 μM) inhibited the expression of fibronectin, type I collagen and CTGF. In addition, imrecoxib reduced the levels of p-ERK1/2. The changes in the expression of related proteins in mouse lung tissue were similar to those in cells. In summary, our findings suggested that the administration of imrecoxib prevented and treated murine IPF by inhibiting inflammation and the TGF-β1-ERK1/2 signaling pathway.

Activation of the NLRP3 inflammasome by HMGB1 through inhibition of the Nrf2/HO-1 pathway promotes bleomycin-induced pulmonary fibrosis after acute lung injury in rats

OBJECTIVE

Acute lung injury (ALI) is a common complication of critical diseases with high morbidity and mortality. This study explored the regulatory role and mechanism of high mobility histone box 1 protein (HMGB1) on pulmonary fibrosis (PF) after ALI in rats through nucleotide oligomerization domain-like receptor protein-3 (NLRP3) inflammasome.

METHODS

PF rat models after ALI were established by induction of bleomycin. Degree of fibrosis was assessed by Masson staining and Ashcroft scoring. Hydroxyproline (Hyp) contents in lung tissues and rat lung tissue morphology were detected by enzyme-linked-immunosorbent serologic assay (ELISA) and hematoxylin and eosin staining. The levels of NLRP3, major proteins of NLRP3 inflammasome (NLRP3/ASC/caspase-1), and downstream inflammatory cytokines interleukin (IL)-1 and IL-18 were determined using immunohistochemistry, Western blotting analysis, and ELISA. The nuclear/cytoplasmic nuclear factor erythroid 2-related factor 2 (Nrf2) levels and HO-1 levels were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting analysis. Rats was injected with lentivirus carrying short hairpin (sh)-HMGB1 and zinc protoporphyria (ZNPP) (HO-1 inhibitor) to assess the effects of HMGB1 and HO-1 on PF and NLRP3 inflammasome activation.

RESULTS

Bleomycin induced PF after ALI in rats, manifested as patchy fibrosis, atelectasis, and excessive expansion, and increased Aschcroft score and Hyp content. Bleomycin treatment enhanced levels of NLRP3, ASC, caspase-1, IL-1, and IL-18 in rat lung tissues, which promoted activation of NLRP3 inflammasome. HMGB1 was up-regulated in bleomycin-induced rats. HMGB1 knockdown partially reversed NLRP3 inflammasome activation and PF progression. HMGB1 knockdown promoted Nrf2 nuclear translocation and up-regulated HO-1. Suppression of HO-1 partially reversed inhibition of HMGB1 knockdown on NLRP3 inflammasome activation and PF.

CONCLUSION

HMGB1 can activate NLRP3 inflammasomes and promote PF by inhibiting the Nrf2/HO-1 pathway.

Andrographolide suppresses breast cancer progression by modulating tumor-associated macrophage polarization through the Wnt/β-catenin pathway

Andrographolide(ADE) has been demonstrated to inhibit tumor growth through direct cytotoxicity on tumor cells. However, its potential activity on tumor microenvironment (TME) remains unclear. Tumor-associated macrophages (TAMs), composed mainly of M2 macrophages, are the key cells that create an immunosuppressive TME by secretion of cytokines, thus enhancing tumor progression. Re-polarized subpopulations of macrophages may represent vital new therapeutic alternatives. Our previous studies showed that ADE possessed anti-metastasis and anoikis-sensitization effects. Here, we demonstrated that ADE significantly suppressed M2-like polarization and enhanced M1-like polarization of macrophages. Moreover, ADE inhibited the migration of M2 and tube formation in HUVECs under M2 stimulation. In vivo studies showed that ADE restrained the growth of MDA-MB-231 and HCC1806 human breast tumor xenografts and 4T-1 mammary gland tumors through TAMs. Wnt5a/β-catenin pathway and MMPs were particularly associated with ADE's regulatory mechanisms to M2 according to RNA-seq and bioinformatics analysis. Moreover， western blot also verified the expressions of these proteins were declined with ADE exposure. Among the cytokines released by M2, PDGF-AA and CCL2 were reduced. Our current findings for the first time elucidated that ADE could modulate macrophage polarization and function through Wnt5a signaling pathway, thereby playing its role in inhibition of triple-negative breast cancer.

AMPK/PPAR-γ/NF-κB axis participates in ROS-mediated apoptosis and autophagy caused by cadmium in pig liver

The experiment was conducted to investigate the effects of Cadmium (Cd) on growth performance, blood biochemical parameters, oxidative stress, hepatocyte apoptosis and autophagy of weaned piglets. A total of 12 healthy weaned piglets were randomly assigned to the control and the Cd group, which were fed with a basal diet and the basal diet supplemented with 15 ± 0.242 mg/kg CdCl₂ for 30 d, respectively. Our results demonstrated that Cd significantly decreased final body weight, average daily feed intake (ADFI), average daily gain (ADG) and increased feed-to-gain (F/G) ratio (P < 0.05). For blood biochemical parameters, Cd treatment significantly decreased the red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), total protein, albumin, copper content and iron content (P < 0.05). In addition, liver injury was observed in the Cd-exposed group. Our results also demonstrated that Cd exposure contributed to the production of ROS, activated the AMPK/PPAR-γ/NF-κB pathway (increasing the expressions of P-AMPK/AMPK, NF-κB, I-κB-β, COX-2, and iNOS, decreasing the expressions of PPAR-γ and I-κB-α), finally induced autophagy (increasing the expressions of Beclin-1, the ratio of LC3-II/LC3-I and p62), and apoptosis (increasing the expressions of Bax, Bak, Caspase-9, and Caspase-3, decreasing the expression of Bcl-2). Overall, these findings revealed the vital role of AMPK/PPAR-γ/NF-κB pathway in Cd-induced liver apoptosis and autophagy, which provided deeper insights into a better understanding of Cd-induced hepatotoxicity.

Molecular pathways and role of epigenetics in the idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with unknown etiological factors that can progress to other dangerous diseases like lung cancer. Environmental and genetic predisposition are the two major etiological or risk factors involved in the pathology of the IPF. Among the environmental risk factors, smoking is one of the major causes for the development of IPF. Epigenetic pathways like nucleosomes remodeling, DNA methylation, histone modifications and miRNA mediated genes play a crucial role in development of IPF. Mutations in the genes make the epigenetic factors as important drug targets in IPF. Transcriptional changes due to environmental factors are also involved in the progression of IPF. The mutations in human telomerase reverse transcriptase (hTERT) have shown decreased life expectancy in IPF patients. The TERT-gene is highly expressed in chronic smokers and makes the role of epigenetics evident. Drug like nintedanib acts through vascular endothelial growth factor receptors (VEGFR), while drug pirfenidone acts through transforming growth factor (TGF), which is useful in IPF. Gefitinib, a tyrosine kinase inhibitor of EGFR, is useful as an anti-fibrosis agent in preclinical models. Newer drugs such as Celgene-CC90001 and FibroGen-FG-3019 are currently under investigations acts through the modulating epigenetic mechanisms. Thus, the study on epigenetics opens a wide window for the discovery of newer drugs. This study provides an elementary analysis of multiple regulators of epigenetics and their roles associated with the pathology of IPF. Further, this review also includes epigenetic drugs under development in preclinical and clinical stages.

Advances in ameliorating inflammatory diseases and cancers by andrographolide: Pharmacokinetics, pharmacodynamics, and perspective

Andrographolide, a well-known natural lactone having a range of pharmacological actions in traditional Chinese medicine. It has long been used to cure a variety of ailments. In this review, we cover the pharmacokinetics and pharmacological activity of andrographolide which supports its further clinical application in cancers and inflammatory diseases. Growing evidence shows a good therapeutic effect in inflammatory diseases, including liver diseases, joint diseases, respiratory system diseases, nervous system diseases, heart diseases, inflammatory bowel diseases, and inflammatory skin diseases. As a result, the effects of andrographolide on immune cells and the processes that underpin them are discussed. The preclinical use of andrographolide to different organs in response to malignancies such as colorectal, liver, gastric, breast, prostate, lung, and oral cancers has also been reviewed. In addition, several clinical trials of andrographolide in inflammatory diseases and cancers have been summarized. This review highlights recent advances in ameliorating inflammatory diseases as well as cancers by andrographolide and its analogs, providing a new perspective for subsequent research of this traditional natural product.

Protective effect of the effective part of Andrographis paniculata (Burm.f.) Nees on PM2.5-induced lung injury in rats by modulating the NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata (Burm.f.) Nees, a traditional Chinese herb, has been widely used in various Asian countries as a treatment for upper respiratory tract infections for centuries.

AIM OF THE STUDY

Continuous inhalation of fine particulate matter (PM_2.5) may induce various respiratory diseases. This study elucidated the protective effect of the effective part of Andrographis paniculata (Burm.f.) Nees (AEP) against PM_2.5-induced lung injury and detailed the underlying mechanism.

MATERIALS AND METHODS

Male Wistar rats were orally administered 0.5% sodium carboxymethylcellulose (CMC-Na), andrographolide (AG) (200 mg/kg) and AEP (100 mg/kg, 200 mg/kg and 400 mg/kg) once a day for 28 days. The rats were intratracheally instilled with PM_2.5 suspension (8 mg/kg) every other day beginning on the 24th day for a total of 3 times. On the 29th day, bronchoalveolar lavage fluid (BALF) was collected to analyze the levels of lactate dehydrogenase (LDH), acid phosphatase (ACP), alkaline phosphatase (AKP), total proteins (TP), tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6). Hematoxylin & eosin staining was conducted to evaluate the pathological changes in the lung tissues. The protein expression of NF-κB p65 in the lung tissues was analyzed by immunohistochemistry staining. Moreover, the nuclear translocation of NF-κB p65 and the phosphorylation of IκBα were analyzed by western blotting.

RESULTS

PM_2.5 exposure caused lung toxicity, which was characterized by pathological injury and increased levels of LDH, ACP, AKP and TP in BALF. Meanwhile, PM_2.5 exposure induced lung inflammatory response, including infiltration of inflammatory cells and increased levels of inflammatory factors, such as TNF-α and IL-6 in BALF. AEP treatment significantly ameliorated the PM_2.5-induced lung toxicity and the inflammatory response in rats. Moreover, AEP significantly inhibited the PM_2.5-induced upregulation of NF-κB p65 protein expression, phosphorylation of IκBα and nuclear translocation of NF-κB p65 in lung tissue. Compared to AG, AEP exhibited a better ability to alleviate PM_2.5-induced pathological damage and decrease the TP level in the BALF.

CONCLUSION

AEP could be used to improve PM_2.5-induced lung injury by modulating the NF-κB pathway, and multicomponent therapy with traditional Chinese medicine may be more effective than single-drug therapy.

Andrographolide Attenuates Gut-Brain-Axis Associated Pathology in Gulf War Illness by Modulating Bacteriome-Virome Associated Inflammation and Microglia-Neuron Proinflammatory Crosstalk

Gulf War Illness (GWI) is a chronic multi-symptomatic illness that is associated with fatigue, pain, cognitive deficits, and gastrointestinal disturbances and presents a significant challenge to treat in clinics. Our previous studies show a role of an altered Gut–Brain axis pathology in disease development and symptom persistence in GWI. The present study utilizes a mouse model of GWI to study the role of a labdane diterpenoid andrographolide (AG) to attenuate the Gut–Brain axis-linked pathology. Results showed that AG treatment in mice (100 mg/kg) via oral gavage restored bacteriome alterations, significantly increased probiotic bacteria Akkermansia, Lachnospiraceae, and Bifidobacterium, the genera that are known to aid in preserving gut and immune health. AG also corrected an altered virome with significant decreases in virome families Siphoviridae and Myoviridae known to be associated with gastrointestinal pathology. AG treatment significantly restored tight junction proteins that correlated well with decreased intestinal proinflammatory mediators IL-1β and IL-6 release. AG treatment could restore Claudin-5 levels, crucial for maintaining the BBB integrity. Notably, AG could decrease microglial activation and increase neurotrophic factor BDNF, the key to neurogenesis. Mechanistically, microglial conditioned medium generated from IL-6 stimulation with or without AG in a concentration similar to circulating levels found in the GWI mouse model and co-incubated with neuronal cells in vitro, decreased Tau phosphorylation and neuronal apoptosis. In conclusion, we show that AG treatment mitigated the Gut–Brain-Axis associated pathology in GWI and may be considered as a potential therapeutic avenue for the much-needed bench to bedside strategies in GWI.

Current Trends on Repurposing and Pharmacological Enhancement of Andrographolide

Andrographolide, the main bioactive component separated from Andrographis paniculata in 1951, has been scrutinized with a modern drug discovery approach for anti-inflammatory properties since 1984. Identification of new uses of existing drugs can be facilitated by searching for evidence linking them to known or yet undiscovered drug targets and human disease states to develop new therapeutic indications.Furthermore, a wide spectrum of biological properties of andrographolide such as anticancer, antibacterial, antiviral, hepatoprotective, antioxidant, anti-malarial, anti-atherosclerosis are also reported. However, poor water solubility and instability limit its clinical application. It becomes crucial to enhance its pharmacological function and find a new treatment option for more diseases. Therefore, this article reviews the major recent developments in andrographolide, including repurposing applications in different diseases and underlying mechanisms, particularly focusing on pharmacological enhancement of andrographolide such as derivatives, chemical modifications with potent biological activity and drug delivery. The repurposing and pharmacological enhancement of andrographolide would not only have exciting therapeutic potential to different diseases to facilitate drug marketing, but also decrease the economic burden on healthcare worldwide.

Andrographolide alleviates bleomycin-induced NLRP3 inflammasome activation and epithelial-mesenchymal transition in lung epithelial cells by suppressing AKT/mTOR signaling pathway

Background

Andrographolide (Andro), a diterpenoid extracted from Andrographis paniculata, has been shown to attenuate pulmonary fibrosis in rodents; however, the potential mechanisms remain largely unclear. This study investigated whether and how Andro alleviates bleomycin (BLM)-induced NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation and epithelial-mesenchymal transition (EMT) in the lung epithelial cells.

Methods

The in vivo effects of Andro were evaluated in a rat model of BLM-induced pulmonary fibrosis. The roles of Andro in BLM-induced NLRP3 inflammasome activation, EMT and AKT/mTOR signaling were investigated using human alveolar epithelial A549 cells.

Results

We found that Andro significantly alleviated pulmonary edema and histopathological changes, decreased weight loss, and reduced collagen deposition. Andro downregulated the levels of NLRP3, the adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC), and Caspase-1 in the lungs of BLM-treated rats, suggesting the inhibitory effect of Andro on NLRP3 inflammasome activation in vivo. Additionally, the symptoms of BLM-mediated EMT phenotype in the lung were also attenuated after Andro administration. In vitro, Andro also markedly inhibited BLM-induced NLRP3 inflammasome activation and EMT in A549 cells. Moreover, Andro inhibited BLM-induced phosphorylation of AKT and mTOR in A549 cells, suggesting that AKT/mTOR inactivation mediates Andro-induced effects on BLM-induced NLRP3 inflammasome activation and EMT.

Conclusions

These data indicate that Andro can reduce BLM-induced pulmonary fibrosis through suppressing NLRP3 inflammasome activation and EMT in lung epithelial cells via AKT/mTOR signaling pathway.

Hirsutella sinensis mycelium regulates autophagy of alveolar macrophages via TLR4/NF-κB signaling pathway

Background: Hirsutella sinensis mycelium (HSM) has potent anti-pulmonary fibrotic activities and has been proposed as an effective treatment for idiopathic pulmonary fibrosis. Macrophages are the main innate immune cells in the lung tissue, playing key roles in pulmonary fibrosis repair and homeostasis. Excessive macrophage autophagy plays a vital role in pulmonary fibrosis. The protective effect of HSM on macrophages of bleomycin (BLM)-induced pulmonary fibrotic mice remain unclear. Methods: In this study, we collected lung tissue and bronchoalveolar lavage fluid (BALF) samples from pulmonary fibrotic mice. Meanwhile, alveolar macrophages were isolated and murine macrophage RAW264.7 cell line was cultured for further study of HSM autophagy. Results: First, we found that HSM decreased the number of autophagosomes, as well as the levels of LC3B and ATG5, and increased the protein level of P62 during the development of pulmonary fibrosis. Meanwhile, HSM reduced alveolar macrophages infiltration into the BALF and inhibited their accumulation in the fibrotic lung tissue. Flow cytometry analysis showed that HSM administration inhibited the autophagy marker LC3B expression in CD11bloCD11chi alveolar macrophages in BLM-induced lung fibrosis without affecting CD11bhiCD11clo interstitial macrophages. Transmission electron microscopy and JC-1 staining for mitochondrial membrane potential of alveolar macrophages also verified that the HSM significantly decreased autophagy in the alveolar macrophages of BLM-treated mice. In vitro, autophagosomes-lysosome fusion inhibitor chloroquine (CQ) was pre-incubated with RAW264.7 cells, and HSM reduced CQ-induced autophagosomes accumulation. TLR4 signaling inhibitor CLI095 reversed the above effects, suggesting HSM could reduce the cumulation of autophagosomes dependent on TLR4. Furthermore, lipopolysaccharide (LPS)-stimulated TLR4-related autophagy was significantly inhibited by HSM treatment. In addition, the protein expressions of TLR4 and phospho-NF-κB p65 were markedly inhibited in cells treated with HSM. Conclusions: These results indicated that HSM could inhibit the autophagy of alveolar macrophages through TLR4/NF-κB signaling pathway to achieve anti-fibrotic effect.

Andrographolide and its fluorescent derivative inhibit the main proteases of 2019-nCoV and SARS-CoV through covalent linkage

The coronavirus disease 2019 (COVID-19) pandemic caused by 2019 novel coronavirus (2019-nCoV) has been a crisis of global health, whereas the effective vaccines against 2019-nCoV are still under development. Alternatively, utilization of old drugs or available medicine that can suppress the viral activity or replication may provide an urgent solution to suppress the rapid spread of 2019-nCoV. Andrographolide is a highly abundant natural product of the medicinal plant, Andrographis paniculata, which has been clinically used for inflammatory diseases and anti-viral therapy. We herein demonstrate that both andrographolide and its fluorescent derivative, the nitrobenzoxadiazole-conjugated andrographolide (Andro- NBD), suppressed the main protease (Mpro) activities of 2019-nCoV and severe acute respiratory syndrome coronavirus (SARS-CoV). Moreover, Andro-NBD was shown to covalently link its fluorescence to these proteases. Further mass spectrometry (MS) analysis suggests that andrographolide formed a covalent bond with the active site Cys145 of either 2019-nCoV Mpro or SARS-CoV Mpro. Consistently, molecular modeling analysis supported the docking of andrographolide within the catalytic pockets of both viral Mpros. Considering that andrographolide is used in clinical practice with acceptable safety and its diverse pharmacological activities that could be beneficial for attenuating COVID-19 symptoms, extensive investigation of andrographolide on the suppression of 2019-nCoV as well as its application in COVID-19 therapy is suggested.

Monocyte chemotactic protein-inducing protein 1 negatively regulating asthmatic airway inflammation and mucus hypersecretion involving γ-aminobutyric acid type A receptor signaling pathway in vivo and in vitro

BACKGROUND

Mounting evidence, consistent with our previous study, showed that γ-aminobutyric acid type A receptor (GABAAR) played an indispensable role in airway inflammation and mucus hypersecretion in asthma. Monocyte chemotactic protein-inducing protein 1 (MCPIP1) was a key negative regulator of inflammation. Recent studies showed that inflammation was largely suppressed by enhanced MCPIP1 expression in many inflammatory diseases. However, the role and potential mechanism of MCPIP1 in airway inflammation and mucus hypersecretion in asthma were still not well studied. This study was to explore the role of MCPIP1 in asthmatic airway inflammation and mucus hypersecretion in both mice and BEAS-2B cells, and its potential mechanism.

METHODS

In vivo, mice were sensitized and challenged by ovalbumin (OVA) to induce asthma. Airway inflammation and mucus secretion were analyzed. In vitro, BEAS-2B cells were chosen. Interleukin (IL)-13 was used to stimulate inflammation and mucus hypersecretion in cells. MCPIP1 Lentiviral vector (LA-MCPIP1) and plasmid-MCPIP1 were used to up-regulate MCPIP1 in lung and cells, respectively. MCP-1, thymic stromal lymphopoietin (TSLP), mucin 5AC (MUC5AC), MCPIP1, and GABAARβ2 expressions were measured in both lung and BEAS-2B cells. Immunofluorescence staining was performed to observe the expression of GABAARβ2 in cells.

RESULTS

MCPIP1 was up-regulated by LA-MCPIP1 (P < 0.001) and plasmid-MCPIP1 (P < 0.001) in lung and cells, respectively. OVA-induced airway inflammation and mucus hypersecretion, OVA-enhanced MCP-1, TSLP, MUC5AC, and GABAARβ2 expressions, and OVA-reduced MCPIP1 were significantly blunted by LA-MCPIP1 in mice (all P < 0.001). IL-13-enhanced MCP-1, TSLP, MUC5AC, and GABAARβ2 expressions, and IL-13-reduced MCPIP1 were markedly abrogated by plasmid-MCPIP1 in BEAS-2B cells (all P < 0.001).

CONCLUSION

The results of this study suggested that OVA and IL-13-induced airway inflammation and mucus hypersecretion were negatively regulated by MCPIP1 in both lung and BEAS-2B cells, involving GABAAR signaling pathway.

Natural products as home-based prophylactic and symptom management agents in the setting of COVID-19

Coronavirus disease (COVID‐19) caused by the novel coronavirus (SARS‐CoV‐2) has rapidly spread across the globe affecting 213 countries or territories with greater than six million confirmed cases and about 0.37 million deaths, with World Health Organization categorizing it as a pandemic. Infected patients present with fever, cough, shortness of breath, and critical cases show acute respiratory infection and multiple organ failure. Likelihood of these severe indications is further enhanced by age as well as underlying comorbidities such as diabetes, cardiovascular, or thoracic problems, as well as due to an immunocompromised state. Currently, curative drugs or vaccines are lacking, and the standard of care is limited to symptom management. Natural products like ginger, turmeric, garlic, onion, cinnamon, lemon, neem, basil, and black pepper have been scientifically proven to have therapeutic benefits against acute respiratory tract infections including pulmonary fibrosis, diffuse alveolar damage, pneumonia, and acute respiratory distress syndrome, as well as associated septic shock, lung and kidney injury, all of which are symptoms associated with COVID‐19 infection. This review highlights the potential of these natural products to serve as home‐based, inexpensive, easily accessible, prophylactic agents against COVID‐19.

Andrographolide attenuates epithelial-mesenchymal transition induced by TGF-β1 in alveolar epithelial cells

Andrographolide (Andro), a component from Chinese medicinal herb Andrographis paniculata, could alleviate pulmonary fibrosis in rodents. Yet, whether and how Andro mitigates epithelial-mesenchymal transition (EMT) induced by TGF-β1 remain unknown. This study aimed to explore the effect of Andro on TGF-β1-induced EMT in human alveolar epithelial cells (AECs) and the mechanisms involved. We illustrated that Andro inhibited TGF-β1-induced EMT and EMT-related transcription factors in alveolar epithelial A549 cells. Andro also reduced TGF-β1-induced cell migration and synthesis of pro-fibrotic factors (ie CCN-2, TGF-β1), matrix metalloproteinases (ie MMP-2, MMP-9) and extracellular matrix (ECM) components (ie collagen 1), implying the inhibiting effect of Andro on TGF-β1-induced EMT-like cell behaviours. Mechanistically, Andro treatment not only repressed TGF-β1-induced Smad2/3 phosphorylation and Smad4 nuclear translocation, but also suppressed TGF-β1-induced Erk1/2 phosphorylation and nuclear translocation in A549 cells. And treatment with ALK5 inhibitor (SB431542) or Erk1/2 inhibitors (SCH772984 and PD98059) remarkably reduced EMT evoked by TGF-β1. In addition, Andro also reduced TGF-β1-induced intracellular ROS generation and NOX4 expression, and elevated antioxidant superoxide dismutase 2 (SOD2) expression, demonstrating the inhibiting effect of Andro on TGF-β1-induced oxidative stress, which is closely linked to EMT. Furthermore, Andro remarkably attenuated TGF-β1-induced down-regulation of sirtuin1 (Sirt1) and forkhead box O3 (FOXO3), implying that Andro protects AECs from EMT partially by activating Sirt1/FOXO3-mediated anti-oxidative stress pathway. In conclusion, Andro represses TGF-β1-induced EMT in AECs by suppressing Smad2/3 and Erk1/2 signalling pathways and is also closely linked to the activation of sirt1/FOXO3-mediated anti-oxidative stress pathway.

Attenuation of Innate Immunity by Andrographolide Derivatives Through NF-κB Signaling Pathway

Andrographolide derivatives or analogs exhibit potent anti-inflammatory effects in several disease models through NF-κB activity. In this study, we synthesized different andrographolide derivatives and investigated their effects on the toll-like receptor (TLR)-induced production of pro-inflammatory cytokines. Among these compounds, 3b, 5a, and 5b inhibited both TNF-α/NF-κB and TLR4/NF-κB signaling pathways. Treatment with compounds 3b, 5a, and 5b and their structural analogs, 3a and 6b, suppressed the expression of pro-inflammatory cytokines upon the activation of TLR3 and TLR4 ligands. Compounds 3b and 5a, but not 3a, 5b, or 6b, inhibited the nuclear translocation of the NF-κB p65 subunit. Treatment with compounds 3b, 5a, 3a, 5b, and 6b attenuated the phosphorylation of p65 and IκBα. Compounds 6b suppressed the expression of the NF-κB p65 subunit. However, these compounds, except for 5b, did not affect the TLR9-induced NF-κB-independent production of the pro-inflammatory cytokines, TNF-α, and IFN-β. Compound 3b potentially protected mice from LPS-induced acute pulmonary inflammation through the inhibition of p65 phosphorylation and the decrease of serum pro-inflammatory cytokines and chemokine. Our study revealed a functional structure–activity relationship between andrographolide derivatives and innate immunity. We identified compound 3b as a potent immune suppressive agent with the potential to protect acute pulmonary infection.

Is there a future for andrographolide to be an anti-inflammatory drug? Deciphering its major mechanisms of action

Andrographis paniculata has long been part of the traditional herbal medicine system in Asia and in Scandinavia. Andrographolide was isolated as a major bioactive constituent of A. paniculata in 1951, and since 1984, andrographolide and its analogs have been scrutinized with modern drug discovery approach for anti-inflammatory properties. With this accumulated wealth of pre-clinical data, it is imperative to review and consolidate different sources of information, to decipher the major anti-inflammatory mechanisms of action in inflammatory diseases, and to provide direction for future studies. Andrographolide and its analogs have been shown to provide anti-inflammatory benefits in a variety of inflammatory disease models. Among the diverse signaling pathways investigated, inhibition of NF-κB activity is the prevailing anti-inflammatory mechanism elicited by andrographolide. There is also increasing evidence supporting endogenous antioxidant defense enhancement by andrographolide through Nrf2 activation. However, the exact pathway leading to NF-κB and Nrf2 activation by andrographolide has yet to be elucidated. Validation and consensus on the major mechanistic actions of andrographolide in different inflammatory conditions are required before translating current findings into clinical settings. There are a few clinical trials conducted using andrographolide in fixed combination formulation which have shown anti-inflammatory benefits and good safety profile. A concerted effort is definitely needed to identify potent andrographolide lead compounds with improved pharmacokinetics and toxicological properties. Taken together, andrographolide and its analogs have great potential to be the next new class of anti-inflammatory agents, and more andrographolide molecules are likely moving towards clinical study stage in the near future.

Recent Update on the Role of Chinese Material Medica and Formulations in Diabetic Retinopathy

Diabetes mellitus is one of the most frequent endocrine disorders, affecting populations worldwide. Diabetic retinopathy (DR) is the most frequent microvascular complication of diabetes in patients aged 20 and over. Major complications of DR include intraocular neovascularization, inter-retinal edema, hemorrhage, exudates and microaneurysms. Therefore, timely medical attention and prevention are required. At present, laser-assisted therapy and other operational procedures are the most common treatment for DR. However, these treatments can cause retinal damage and scarring. Also, use of the majority of traditional medicines is not supported by clinical evidence. However, due to accumulating scientific evidence, traditional natural medications may assist in delaying or preventing the progression of DR. This review focuses on evidence for the role of traditional natural medicines and their mechanisms of action and pharmacological test results in relation to the progression of DR.

Emodin alleviates bleomycin-induced pulmonary fibrosis in rats

Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease with few treatment options and poor prognosis. Emodin, extracted from Chinese rhubarb, was found to be able to alleviate bleomycin (BLM)-induced pulmonary fibrosis, yet the underlying mechanism remains largely unknown. This study aimed to further investigate the effects of emodin on the inflammation and fibrosis of BLM-induced pulmonary fibrosis and the mechanism involved in rats. Our results showed that emodin improved pulmonary function, reduced weight loss and prevented death in BLM-treated rats. Emodin significantly relieved lung edema and fibrotic changes, decreased collagen deposition, and suppressed the infiltration of myofibroblasts [characterized by expression of α-smooth muscle actin (α-SMA)] and inflammatory cells (mainly macrophages and lymphocytes). Moreover, emodin reduced levels of TNF-α, IL-6, TGF-β1 and heat shock protein (HSP)-47 in the lungs of BLM-treated rats. In vitro, emodin profoundly inhibited TGF-β1-induced α-SMA, collagen IV and fibronectin expression in human embryo lung fibroblasts (HELFs). Emodin also inhibited TGF-β1-induced Smad2/3 and STAT3 activation, indicating that Smad2/3 and STAT3 inactivation mediates emodin-induced effects on TGF-β1-induced myofibroblast differentiation. These results suggest that emodin can exert its anti-fibrotic effect via suppression of TGF-β1 signaling and subsequently inhibition of inflammation, HSP-47 expression, myofibroblast differentiation and extracellular matrix (ECM) deposition.

Recombinant human brain natriuretic peptide attenuates LPS-induced cellular injury in human fetal lung fibroblasts via inhibiting MAPK and NF-κB pathway activation

Inflammatory responses are vital in lung injury diseases, particularly acute respiratory distress syndrome (ARDS). Recombinant human brain natriuretic peptide (rhBNP) has been shown to exhibit anti‑inflammatory effects in vivo in our previous studies. The present study aimed to investigate the mechanisms underlying the anti‑inflammatory effects of rhBNP on lipopolysaccharide (LPS)-induced human fetal lung fibroblasts (HFL-1). The results showed that LPS induced a significant increase in the leakage of lactate dehydrogenase and the secretion of interleukin (IL)‑1β. Activation of p38, extracellular-signal regulated kinase (ERK) 1/2, c‑Jun NH2-terminal kinase (JNK) mitogen‑activated protein kinases (MAPK)s, and nuclear factor (NF)‑κB in HFL‑1 cells was also observed following treatment with LPS. Treatment with rhBNP (0.1 µM) reduced the production of IL‑1β at the protein and mRNA levels. Moreover, rhBNP decreased the phosphorylation of p38, ERK1/2 and JNK induced by LPS. However, the JNK inhibitor, SP600125, significantly inhibited LPS‑induced IL‑1β production. These results indicate that the inhibition of IL‑1β by may dependent upon the JNK signaling pathway. The LPS‑induced NF‑κB activation was also suppressed by rhBNP, and IL‑1β production was inhibited by the NF‑κB inhibitor. Furthermore, NF‑κB activation was attenuated by the JNK inhibitor, indicating that NF‑κB activation was dependent on the JNK signaling pathway. The present study suggests that rhBNP exhibits an anti‑inflammatory effect on LPS‑induced HFL‑1 cell injury via the inhibition of MAPK and NF‑κB signaling pathways and may exhibit therapeutic potential for acute lung injury and ARDS.

Organic acid component from Taraxacum mongolicum Hand.-Mazz alleviates inflammatory injury in lipopolysaccharide-induced acute tracheobronchitis of ICR mice through TLR4/NF-κB signaling pathway

Inflammation plays an important role in the pathogenesis of acute tracheobronchitis. Taraxacum mongolicum Hand.-Mazz (TMHM) is a dietic herb for heat-clearing and detoxifying functions as well as swell-reducing and mass-resolving effect in Traditional Chinese Medicine. Studies have shown that its major ingredient organic acid component (OAC) possesses favorable anti-inflammatory activity. However, the protective effect of OAC from TMHM (TMHM-OAC) on inflammatory injury of acute tracheobronchitis and its possible mechanism remains poorly understood. In this study, HPLC-DAD was used to analyze the components of TMHM-OAC. Lipopolysaccharide of 1mg/ml was used to induce respiratory inflammation in ICR mice at the dose of 5mg/kg by intratracheally aerosol administration. Enzyme-linked immunosorbent assay (ELISA) was employed to detect the levels of inflammation factors such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and nitric oxide in serum and supernatant of trachea tissue. Western blotting (WB) and Immunohistochemistry analysis (IHC) were conducted in parallel to determine TNF-α, IL-6, inducible nitric oxide synthase (iNOS), Toll-like receptors 4(TLR4) protein expressions and nuclear factor-kappa B p65 (NF-κB p65) phosphorylation. Hematoxylin-Eosin staining (HE) was applied to evaluate pathological lesions of trachea tissue. Experimental results showed that TMHM-OAC significantly reduced the levels of the TNF-α, IL-6 and NO in serum and supernatant of tracheal of LPS-induced ICR mice. The protein expression levels of TNF-α, IL-6 and iNOS in tracheal tissue were also down-regulated significantly by the treatment of TMHM-OAC. Moreover, TMHM-OAC downregulated phosphorylation of NF-κB p65 and protein expression of TLR4. Our results indicated that TMHM-OAC could improve LPS-induced histopathological damage of tracheal tissues through the regulation of TLR4/NF-κB signaling pathway and could be beneficial for the treatment of acute tracheobronchitis.

Epithelial-mesenchymal transition: An emerging target in tissue fibrosis

Epithelial-mesenchymal transition (EMT) is involved in a variety of tissue fibroses. Fibroblasts/myofibroblasts derived from epithelial cells contribute to the excessive accumulation of fibrous connective tissue in damaged tissue, which can lead to permanent scarring or organ malfunction. Therefore, EMT-related fibrosis cannot be neglected. This review highlights the findings that demonstrate the EMT to be a direct contributor to the fibroblast/myofibroblast population in the development of tissue fibrosis and helps to elucidate EMT-related anti-fibrotic strategies, which may enable the development of therapeutic interventions to suppress EMT and potentially reverse organ fibrosis.

Glucagon Like Peptide-1 (GLP-1) Modulates OVA-Induced Airway Inflammation and Mucus Secretion Involving a Protein Kinase A (PKA)-Dependent Nuclear Factor-κB (NF-κB) Signaling Pathway in Mice

Asthma is a common chronic pulmonary inflammatory disease, featured with mucus hyper-secretion in the airway. Recent studies found that glucagon like peptide-1 (GLP-1) analogs, including liraglutide and exenatide, possessed a potent anti-inflammatory property through a protein kinase A (PKA)-dependent signaling pathway. Therefore, the aim of current study was to investigate the value of GLP-1 analog therapy liraglutide in airway inflammation and mucus secretion in a murine model of ovalbumin (OVA)-induced asthma, and its underlying molecular mechanism. In our study, BALB/c mice were sensitized and challenged by OVA to induce chronic asthma. Pathological alterations, the number of cells and the content of inflammatory mediators in bronchoalveolar lavage fluid (BALF), and mucus secretion were observed and measured. In addition, the mRNA and protein expression of E-selectin and MUC5AC were analyzed by qPCR and Western blotting. Then, the phosphorylation of PKA and nuclear factor-κB (NF-κB) p65 were also measured by Western blotting. Further, NF-κB p65 DNA binding activity was detected by ELISA. OVA-induced airway inflammation, airway mucus hyper-secretion, the up-regulation of E-selectin and MUC5AC were remarkably inhibited by GLP-1 in mice (all p < 0.01). Then, we also found that OVA-reduced phosphorylation of PKA, and OVA-enhanced NF-κB p65 activation and NF-κB p65 DNA binding activity were markedly improved by GLP-1 (all p < 0.01). Furthermore, our data also figured out that these effects of GLP-1 were largely abrogated by the PKA inhibitor H-89 (all p < 0.01). Taken together, our results suggest that OVA-induced asthma were potently ameliorated by GLP-1 possibly through a PKA-dependent inactivation of NF-κB in mice, indicating that GLP-1 analogs may be considered an effective and safe drug for the potential treatment of asthma in the future.

The role of the NLRP3 inflammasome in pulmonary diseases

Respiratory diseases and lung injuries are one of the leading causes of death in the world. One critical component of these diseases is exaggerated inflammatory response. The recently discovered inflammasome is believed to play a key role in inflammation. The inflammasome is an oligomer of intracellular proteins that, once activated by an insult or damage signal, produces mature cytokines from the interleukin-1 family that mediate an inflammatory response. Previous research has provided evidence that suggests the role of the inflammasome in the pathogenesis of many chronic respiratory diseases and acute lung injuries, such as transfusion-related acute lung injury, ventilator-induced lung injury, asthma, chronic obstructive pulmonary disease and pulmonary fibrosis. This article summarizes recent research on the inflammasome and reviews proposed molecular models of the role of the inflammasome in several prominent lung diseases and injuries.

Anti-profibrotic effects of artesunate on bleomycin-induced pulmonary fibrosis in Sprague Dawley rats

The present study aimed to determine whether artesunate has beneficial effects on bleomycin-induced pulmonary fibrosis in rats and to examine the possible mechanisms underlying these effects. All experiments were performed with male Sprague Dawley rats weighing 180-250 g. Animals were randomly divided into four experimental groups that were administered either saline alone, artesunate alone, bleomycin alone or bleomycin + artesunate. Lung histopathology was investigated by hematoxylin and eosin staining and Masson staining. Lung profibrotic molecules were analyzed by reverse transcription polymerase chain reaction, immunoblotting and immunohistochemistry. In rats treated with artesunate, pulmonary fibrosis induced by bleomycin was significantly reduced. Administration of artesunate significantly improved bleomycin-induced morphological alterations. Profibrotic molecules, including transforming growth factor-β1, Smad3, heat shock protein 47, α-smooth muscle actin and collagen type I were also reduced by artesunate. These findings suggest that artesunate improves bleomycin-induced pulmonary fibrosis pathology in rats possibly by inhibiting profibrotic molecules associated with pulmonary fibrosis.

Emodin ameliorates LPS-induced acute lung injury, involving the inactivation of NF-κB in mice

Acute lung injury (ALI) and its severe manifestation of acute respiratory distress syndrome (ARDS) are well-known illnesses. Uncontrolled and self-amplified pulmonary inflammation lies at the center of the pathology of this disease. Emodin, the bio-active coxund of herb Radix rhizoma Rhei, shows potent anti-inflammatory properties through inactivation of nuclear factor-κB (NF-κB). The aim of this study was to evaluate the effect of emodin on lipopolysaccharide (LPS)-induced ALI in mice, and its potential bio-mechanism. In our study, BALB/c mice were stimulated with LPS to induce ALI. After 72 h of LPS stimulation, pulmonary pathological changes, lung injury scores, pulmonary edema, myeloperoxidase (MPO) activity, total cells, neutrophils, macrophages, TNF-α, IL-6 and IL-1β in bronchoalveolar lavage fluid (BALF), and MCP-1 and E-selectin expression were notably attenuated by emodin in mice. Meanwhile, our data also revealed that emodin significantly inhibited the LPS-enhanced the phosphorylation of NF-κB p65 and NF-κB p65 DNA binding activity in lung. Our data indicates that emodin potently inhibits LPS-induced pulmonary inflammation, pulmonary edema and MCP-1 and E-selectin expression, and that these effects were very likely mediated by inactivation of NF-κB in mice. These results suggest a therapeutic potential of emodin as an anti-inflammatory agent for ALI/ARDS treatment.

Integrated analyses identify the involvement of microRNA-26a in epithelial-mesenchymal transition during idiopathic pulmonary fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and highly lethal fibrotic lung disease with poor treatment and unknown etiology. Emerging evidence suggests that epithelial-mesenchymal transition (EMT) has an important role in repair and scar formation following epithelial injury during pulmonary fibrosis. Although some miRNAs have been shown to be dysregulated in the pathophysiological processes of IPF, limited studies have payed attention on the participation of miRNAs in EMT in lung fibrosis. In our study, we identified and constructed a regulation network of differentially expressed IPF miRNAs and EMT genes. Additionally, we found the downregulation of miR-26a in mice with experimental pulmonary fibrosis. Further studies showed that miR-26a regulated HMGA2, which is a key factor in the process of EMT and had the maximum number of regulating miRNAs in the regulation network. More importantly, inhibition of miR-26a resulted in lung epithelial cells transforming into myofibroblasts in vitro and in vivo, whereas forced expression of miR-26a alleviated TGF-β1- and BLM-induced EMT in A549 cells and in mice, respectively. Taken together, our study deciphered the essential role of miR-26a in the pathogenesis of EMT in pulmonary fibrosis, and suggests that miR-26a may be a potential therapeutic target for IPF.