Salidroside mitigates skeletal muscle atrophy in rats with cigarette smoke-induced COPD by up-regulating myogenin and down-regulating myostatin expression

Altered skeletal muscle function and beneficial effects of exercise training in a rat model of induced pulmonary emphysema

AIM

Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow obstruction and development of emphysema. Among the comorbidities associated with COPD, skeletal muscle dysfunction is known to affect exercise capacity and the survival rate of patients. Pulmonary rehabilitation (PR), via exercise training, is essential for COPD patients. However, the response to PR is most often moderate. An animal model that recapitulates critical features of chronic human disease and provides access to muscle function should therefore be useful to improve PR benefits.

METHODS

We used a rat model of induced emphysema based on pulmonary instillations of elastase (ELA) and lipopolysaccharides (LPS). We assessed the long-term effects of ELA/LPS and the potential effectiveness of endurance training on the skeletal muscle function. In vivo strength of the animals, and ex vivo contractility, endurance, type 1 fiber proportion, fiber cross-sectional area, and capillarization of both soleus and extensor digitorum longus (EDL) were assessed.

RESULTS

An impaired overall muscle strength with decreased force, reduced capillarization, and atrophy of type 1 fiber of EDL was observed in ELA/LPS rats. Soleus was not affected. Endurance training was able to reduce fatigability, and increase type 1 fiber proportion and capillarization of soleus, and improve force, endurance, and capillarization of EDL in control and ELA/LPS rats.

CONCLUSION

Our rat model of induced emphysema, which shares some features with the phenotype present in patients with COPD, could represent a suitable model to study skeletal muscle dysfunction and the effects of exercise training on muscle function in patients.

P. gingivalis alters lung microbiota and aggravates disease severity of COPD rats by up-regulating Hsp90α/MLKL

Background

Epidemiological evidence has confirmed that periodontitis is an essential and independent risk factor of chronic obstructive pulmonary disease (COPD). Porphyromonas gingivalis, a major pathogen implicated in periodontitis, may make a vital contribution to COPD progression. However, the specific effects and molecular mechanism of the link between P. gingivalis and COPD are not clear.

Methods and Results

A COPD rat model was constructed by smoke exposure combined intratracheal instillation of E. coli-LPS, then P. gingivalis was introduced into the oral cavity of COPD rats. This research observed that lower lung function, more severe alveolar damage and inflammation occurred in COPD rats with P. gingivalis group. Meanwhile, P. gingivalis/gingipains could colonize the lung tissues and be enriched in bronchoalveolar lavage fluid (BALF) of COPD rats with P. gingivalis group, along with alterations in lung microbiota. Proteomic analysis suggested that Hsp90α/MLKL-meditated necroptosis pathway was up-regulated in P. gingivalis-induced COPD aggravation, the detection of Hsp90α and MLKL in serum and lung tissue verified that Hsp90α/MLKL was up-regulated.

Conclusion

These results indicate that P. gingivalis could emigrate into the lungs, alter lung microbiota and lead to aggravation of COPD, which Hsp90α/MLKL might participate in.

Molecular Mechanisms and the Interplay of Important Chronic Obstructive Pulmonary Disease Biomarkers Reveals Novel Therapeutic Targets

Chronic Obstructive Pulmonary Disease (COPD) is a progressive, age-dependent, and unmet chronic inflammatory disease of the peripheral airways, leading to difficulty in exhalation. Several biomarkers have been tested in general towards the resolution for a long time, but no apparent success was achieved. Ongoing therapies of COPD have only symptomatic relief but no cure. Reactive oxygen species (ROS) are highly reactive species which include oxygen radicals and nonradical derivatives, and are the prominent players in COPD. They are produced as natural byproducts of cellular metabolism, but their levels can vary due to exposure to indoor air pollution, occupational pollution, and environmental pollutants such as cigarette smoke. In COPD, the lungs are continuously exposed to high levels of ROS thus leading to oxidative stress. ROS can cause damage to cells, proteins, lipids, and DNA which further contributes to the chronic inflammation in COPD and exacerbates the disease condition. Excessive ROS production can overwhelm cellular antioxidant systems and act as signaling molecules that regulate cellular processes, including antioxidant defense mechanisms involving glutathione and sirtuins which further leads to cellular apoptosis, cellular senescence, inflammation, and sarcopenia. In this review paper, we focused on COPD from different perspectives including potential markers and different cellular processes such as apoptosis, cellular senescence, inflammation, sirtuins, and sarcopenia, and tried to connect the dots between them so that novel therapeutic strategies to evaluate and target the possible underlying mechanisms in COPD could be explored.

Revisiting Skeletal Muscle Dysfunction and Exercise in Chronic Obstructive Pulmonary Disease: Emerging Significance of Myokines

Skeletal muscle dysfunction (SMD) is the most significant extrapulmonary complication and an independent prognostic indicator in patients with chronic obstructive pulmonary disease (COPD). Myokines, such as interleukin (IL)-6, IL-15, myostatin, irisin, and insulin-like growth factor (IGF)-1, play important roles in skeletal muscle mitochondrial function, protein synthesis and breakdown balance, and regeneration of skeletal muscles in COPD. As the main component of pulmonary rehabilitation, exercise can improve muscle strength, muscle endurance, and exercise capacity in patients with COPD, as well as improve the prognosis of SMD and COPD by regulating the expression levels of myokines. The mechanisms by which exercise regulates myokine levels are related to microRNAs. IGF-1 expression is upregulated by decreasing the expression of miR-1 or miR-29b. Myostatin downregulation and irisin upregulation are associated with increased miR-27a expression and decreased miR-696 expression, respectively. These findings suggest that myokines are potential targets for the prevention and treatment of SMD in COPD. A comprehensive analysis of the role and regulatory mechanisms of myokines can facilitate the development of new exercise-based therapeutic approaches for patients with COPD.

Salidroside ameliorated the pulmonary inflammation induced by cigarette smoke via mitigating M1 macrophage polarization by JNK/c-Jun

Pulmonary inflammation induced by cigarette smoke (CS) promoted the development of chronic obstructive pulmonary disease (COPD), and macrophage polarization caused by CS modulated inflammatory response. Previous studies indicated that salidroside exerted therapeutic effects in COPD, but the anti-inflammatory mechanisms were not clear. This study aimed to explore the effects and mechanisms of salidroside on macrophage polarization induced by CS. Wistar rats received passively CS exposure and were treated intraperitoneally with salidroside at a low, medium or high dose. Lung tissues were stained with hematoxylin-eosin. Emphysema and inflammatory scores were evaluated by histomorphology. Lung function, cytokines, and cell differential counts in BALF were detected. The macrophage polarization was determined by immunohistochemistry in lung tissues. Alveolar macrophages (AMs) were isolated and treated with cigarette smoke extract (CSE), salidroside or inhibitors of relative pathways. The polarization status was determined by qPCR, and the protein level was detected by Western blotting. CS exposure induced emphysema and lung function deterioration. The inflammatory scores, cytokines level and neutrophils counts were elevated after CS exposure. Salidroside treatment partly ameliorated above abnormal. CS exposure activated M1 and M2 polarization of AMs in vivo and in vitro, and salidroside mitigated M1 polarization induced by CS. CSE activated the JNK/c-Jun in AMs and the M1 polarization of AMs was inhibited by the inhibitors of JNK and AP-1. Salidroside treatment deactivated the JNK/c-Jun, which indicated that salidroside mitigated the M1 polarization of AMs induced by CS via inhibiting JNK/c-Jun. Salidroside treatment ameliorated the pulmonary inflammation and M1 polarization of AMs induced by CS, and the process might be mediated by the deactivation of JNK/c-Jun.

Oxidative stress: roles in skeletal muscle atrophy

Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.

Advances in traditional Chinese medicine for the treatment of chronic obstructive pulmonary disease

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally and thus imposes heavy economic burden on patients, their families, and society. Furthermore, COPD seriously affects the quality of life of patients. The concept of "overall regulation" of traditional Chinese medicine (TCM) plays an important role in the prevention and treatment of COPD.

AIM OF THE STUDY

The objective of this review is to summarize the TCM theories, experimental methods, TCM extracts, active TCM ingredients, and TCM formulas for the treatment of COPD and reveal the effects and mechanisms of TCM treatments on COPD.

MATERIALS AND METHODS

This article reviewed literature on TCM-based treatments for COPD reported from 2016 to 2021. Relevant scientific studies were obtained from databases that included PubMed, China National Knowledge Infrastructure, Web of Science, Google Scholar, The Plant List, ScienceDirect, and SciFinder.

RESULTS

This review summarized TCM-based theory, experimental methods, active ingredients, and potential toxicities, the effects of TCM extracts and formulations, and their mechanisms for the treatment of COPD. Most investigators have used in vivo models of cigarette smoke combined with lipopolysaccharide induction in rats and in vitro models of cigarette smoke extract induction. The active ingredients of TCM used for the treatment of COPD in relevant studies were triterpenoids, flavonoids, phenolics, quinones, glycosides, and alkaloids. TCMs commonly used in the treatment of COPD include antipyretic drugs, tonic medicines, anticough medications, and asthma medications. TCM can treat COPD by suppressing inflammation, reducing oxidative stress, inhibiting apoptosis, and improving airway remodeling.

CONCLUSIONS

This review enriches the theory of COPD treatments based on TCM, established the clinical significance and development prospects of TCM-based COPD treatments, and provided the necessary theoretical support for the further development of TCM resources for the treatment of COPD.

Main Pathogenic Mechanisms and Recent Advances in COPD Peripheral Skeletal Muscle Wasting

Chronic obstructive pulmonary disease (COPD) is a worldwide prevalent respiratory disease mainly caused by tobacco smoke exposure. COPD is now considered as a systemic disease with several comorbidities. Among them, skeletal muscle dysfunction affects around 20% of COPD patients and is associated with higher morbidity and mortality. Although the histological alterations are well characterized, including myofiber atrophy, a decreased proportion of slow-twitch myofibers, and a decreased capillarization and oxidative phosphorylation capacity, the molecular basis for muscle atrophy is complex and remains partly unknown. Major difficulties lie in patient heterogeneity, accessing patients' samples, and complex multifactorial process including extrinsic mechanisms, such as tobacco smoke or disuse, and intrinsic mechanisms, such as oxidative stress, hypoxia, or systemic inflammation. Muscle wasting is also a highly dynamic process whose investigation is hampered by the differential protein regulation according to the stage of atrophy. In this review, we report and discuss recent data regarding the molecular alterations in COPD leading to impaired muscle mass, including inflammation, hypoxia and hypercapnia, mitochondrial dysfunction, diverse metabolic changes such as oxidative and nitrosative stress and genetic and epigenetic modifications, all leading to an impaired anabolic/catabolic balance in the myocyte. We recapitulate data concerning skeletal muscle dysfunction obtained in the different rodent models of COPD. Finally, we propose several pathways that should be investigated in COPD skeletal muscle dysfunction in the future.

Inflammation: Roles in Skeletal Muscle Atrophy

Various diseases can cause skeletal muscle atrophy, usually accompanied by inflammation, mitochondrial dysfunction, apoptosis, decreased protein synthesis, and enhanced proteolysis. The underlying mechanism of inflammation in skeletal muscle atrophy is extremely complex and has not been fully elucidated, thus hindering the development of effective therapeutic drugs and preventive measures for skeletal muscle atrophy. In this review, we elaborate on protein degradation pathways, including the ubiquitin-proteasome system (UPS), the autophagy-lysosome pathway (ALP), the calpain and caspase pathways, the insulin growth factor 1/Akt protein synthesis pathway, myostatin, and muscle satellite cells, in the process of muscle atrophy. Under an inflammatory environment, various pro-inflammatory cytokines directly act on nuclear factor-κB, p38MAPK, and JAK/STAT pathways through the corresponding receptors, and then are involved in muscle atrophy. Inflammation can also indirectly trigger skeletal muscle atrophy by changing the metabolic state of other tissues or cells. This paper explores the changes in the hypothalamic-pituitary-adrenal axis and fat metabolism under inflammatory conditions as well as their effects on skeletal muscle. Moreover, this paper also reviews various signaling pathways related to muscle atrophy under inflammatory conditions, such as cachexia, sepsis, type 2 diabetes mellitus, obesity, chronic obstructive pulmonary disease, chronic kidney disease, and nerve injury. Finally, this paper summarizes anti-amyotrophic drugs and their therapeutic targets for inflammation in recent years. Overall, inflammation is a key factor causing skeletal muscle atrophy, and anti-inflammation might be an effective strategy for the treatment of skeletal muscle atrophy. Various inflammatory factors and their downstream pathways are considered promising targets for the treatment and prevention of skeletal muscle atrophy.

Natural products in the treatment of pulmonary emphysema: Therapeutic effects and mechanisms of action

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a class of lung diseases including chronic bronchitis, asthma, and emphysema. Long-time smoking is considered the main reason for developing emphysema. Emphysema can be defined as damage to the walls of the air sacs (alveoli) of the lung. It has been demonstrated that natural compounds with antioxidant and anti-inflammatory effects can effectively improve or protect the lung against this disease. This paper is dedicated to systematically review the effective natural compounds in the treatment of pulmonary emphysema.

PURPOSE

This is the first systematic and comprehensive review on the role of plant-derived secondary metabolites in managing and/or treating pulmonary emphysema STUDY DESIGN AND METHODS: A systematic and comprehensive review was done based on Scopus, PubMed, and Cochrane Library databases were searched using the "emphysema", "plant", "herb", and "phytochemical" keywords. Non-English, review, and repetitive articles were excluded from the study. Search results were included in the Prisma diagram.

RESULTS

From a total of 1285 results, finally, 22 articles were included in the present study. The results show that some herbs such as Scutellaria baicalensis Georgi and Monascus adlay and some phytochemicals such as gallic acid and quercetin and blackboard tree indole alkaloids affect more factors in improving the lung emphysema. Also, some natural compounds such as marijuana smoke and humic acid also play an aggravating role in this disease. It also seems that some of the medicinal plants such as PM014 herbal formula, pomegranate juice and açaí berry sometimes have side effects that are inconsistent with their therapeutic effects.

CONCLUSION

We concluded that natural compounds can effectively improve pulmonary emphysema due to their antioxidant, anti-inflammatory, and anti-apoptotic properties. However, additional studies are suggested to prove efficacy and side effects.

Potential Natural Small Molecular Compounds for the Treatment of Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is one of the major diseases threatening human life and health. According to the report released by the World Health Organization (WHO) in 2020, COPD has become the third leading cause of death in the world, featuring a sustainable growth of incidence rate as well as population age. The purpose of this review focuses on the advancement of bioactive natural compounds, such as baicalin, quercetin, resveratrol, and curcumin, which demonstrate promising therapeutic/interventional effects on CODP in vitro and in vivo. Information emphasizing on COPD was systematically collected from several authoritative internet databases including Web of Science, PubMed, Elsevier, Wiley Online Library, and Europe PMC, with a combination of keywords containing “COPD” and “natural small molecular compounds”. The new evidence indicated that these valuable molecules featured unique functions in the treatment of COPD through various biological processes such as anti-inflammatory, anti-oxidant, anti-apoptosis, and anti-airway fibrosis. Moreover, we found that the promising effects of these natural compounds on COPD were mainly achieved through JAK3/STAT3/NF-κB and MAPK inflammatory signaling pathways, Nrf2 oxidative stress signaling pathway, and TGF-β1/Smad 2/3 fibrosis signaling pathway, which referenced to multiple targets like TNF-α, IL-6, IL-8, TIMP-1, MMP, AKT, JAK3, IKK, PI3K, HO-1, MAPK, P38, ERK, etc. Current challenges and future directions in this promising field are also discussed at the end of this review. For the convenience of the readers, this review is divided into ten parts according to the structures of potential natural small molecular compounds. We hope that this review brings a quick look and provides some inspiration for the research of COPD.

Endurance exercise training suppresses myostatin upregulation and nuclear factor-kappa B activation in a mouse model of Parkinson's disease

Background and Aim:

Muscle atrophy is common in Parkinson’s disease (PD). Although myostatin has been implicated in muscle atrophy, its expression in PD skeletal muscle has not been investigated. Therefore, this study aimed to elucidate the influence of PD induction and exercise training on myostatin expression in the gastrocnemius skeletal muscle.

Materials and Methods:

Thirty albino mice were randomly selected and separated into three groups of 10 mice each: Sedentary control, sedentary PD (SPD), and exercised PD (EPD). 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid were used to induce chronic parkinsonism in the PD groups. Immunohistochemistry was used to investigate the expression of myostatin and nuclear factor kappa B (NF-kB) in gastrocnemius muscles of all three groups.

Results:

Myostatin expression and NF-kB nuclear localization, indicative of its activation, were significantly (p<0.01) higher in gastrocnemius skeletal muscle in the SPD group than in the control and EPD groups. Concomitantly, the average cross-sectional area of gastrocnemius muscle fibers in the SPD albino mice was significantly smaller (p<0.01) than in the control and EPD groups, indicating muscle atrophy.

Conclusion:

The present data are the first to indicate a correlation between PD induction and myostatin overexpression and NF-kB activation in the gastrocnemius muscle, potentially promoting the muscle atrophy commonly seen in PD. Additionally, the current data are the first to indicate the beneficial effects of exercise training on PD-associated myostatin overexpression, NF-κB activation, and muscle atrophy. Thus, our data are the first to suggest that myostatin and NF-κB might be regarded as potential therapeutic targets in an attempt to ameliorate skeletal muscle abnormalities commonly observed in PD.

Therapeutic effects of salidroside vs pyrrolidine dithiocarbamate against severe acute pancreatitis in rat

OBJECTIVE

To evaluate the therapeutic effectiveness of salidroside (Sal) and pyrrolidine dithiocarbamate (PDTC) against severe acute pancreatitis (SAP) in a rat model.

METHODS

Rat models of SAP were established by retrograde infusion of sodium taurocholate solution. SAP rats were randomly divided into 6 groups: SAP 3 h group, SAP 24 h group, low-dose Sal treatment group (Sal L+S), middle-dose Sal treatment group (Sal M+S), high-dose Sal treatment group (Sal H+S) and PDTC treatment group (PDTC+S). The serum amylase, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-10 (IL-10) levels were determined by optical turbidimetry and enzyme-linked immunosorbent assay. The expression of Beclin-1, microtubule-associated protein light chain 3II (LC3 II ), lysosome associated membrane protein 2 (LAMP2), interleukin-1 receptor associated kinase 1 (IRAK1) inhibitor α of nuclear transcription factor-kB (IkBα), nuclear transcription factor-kB 65 (p65) in the pancreas tissues were detected by quantitative real-time polymerase chain reaction and Western blot, while the pIkBα and p-p65 levels were detected by Western blot. Pathological changes of the pancreas and all the other indexes were observed at 3 and 24 h after operation.

RESULTS

The serum IL-10 level, IkBα and LAMP2 levels in Sal M+S, Sal H+S and PDTC+S groups were higher than those in SAP 24 h group, while all the other indexes in these three groups were all lower significantly than those in SAP 24 h group. There was no significant difference in all indexes between Sal H+S and PDTC+S groups.

CONCLUSION

High-dose Sal has an effectively therapeutic effect on SAP in rats, which was similar to PDTC.

Berberine Alleviates Gastroesophageal Reflux-Induced Airway Hyperresponsiveness in a Transient Receptor Potential A1-Dependent Manner

BACKGROUND

To investigate the beneficial effect of berberine on gastroesophageal reflux-induced airway hyperresponsiveness (GERAHR) and explore the underlying mechanism.

METHODS

Coword cluster analysis and strategic coordinates were used to identify hotspots for GERAHR research, and an online tool (STRING, https://string-db.org/) was used to predict the potential relationships between proteins. Guinea pigs with chemically induced GERAHR received PBS or different berberine-based treatments to evaluate the therapeutic effect of berberine and characterize the underlying mechanism. Airway responsiveness was assessed using a plethysmography system, and protein expression was evaluated by western blotting, immunohistochemical staining, and quantitative PCR analysis.

RESULTS

Bioinformatics analyses revealed that TRP channels are hotspots of GERAHR research, and TRPA1 is related to the proinflammatory neuropeptide substance P (SP). Berberine, especially at the middle dose tested (MB, 150 mg/kg), significantly improved lung function, suppressed inflammatory cell infiltration, and protected inflammation-driven tissue damage in the lung, trachea, esophagus, and nerve tissues in GERAHR guinea pigs. MB reduced the expression of TRPA1, SP, and tumor necrosis factor-alpha (TNF-α) in evaluated organs and tissues. Meanwhile, the MB-mediated protective effects were attenuated by simultaneous TRPA1 activation.

CONCLUSIONS

Mechanistically, berberine was found to suppress GERAHR-induced upregulation of TRPA1, SP, and TNF-α in many tissues. Our study has highlighted the potential therapeutic value of berberine for the treatment of GERAHR.

Research progress in immune microenvironment regulation of muscle atrophy induced by peripheral nerve injury

Denervated skeletal muscular atrophy is primarily characterized by loss of muscle strength and mass and an unideal functional recovery of the muscle after extended denervation. This review emphasizes the interaction between the immune system and the denervated skeletal muscle. Immune cells such as neutrophils, macrophages and T-cells are activated and migrate to denervated muscle, where they release a high concentration of cytokines and chemokines. The migration of these immune cells, the transformation of different functional immune cell subtypes, and the cytokine network in the immune microenvironment may be involved in the regulatory process of muscle atrophy or repair. However, the exact mechanisms of the interaction between these immune cells and immune molecules in skeletal muscles are unclear. In this paper, the immune microenvironment regulation of muscle atrophy induced by peripheral nerve injury is reviewed.

Rosiglitazone ameliorated airway inflammation induced by cigarette smoke via inhibiting the M1 macrophage polarization by activating PPARγ and RXRα

BACKGROUND

Rosiglitazone, an exogenous ligand of PPARγ, plays an important anti-inflammatory role during the inflammation caused by cigarette smoke (CS). CS exposure induces pulmonary inflammation via activating macrophage polarization. However, the effects of rosiglitazone on macrophage polarization induced by CS are unclear.

METHODS

36 male Wistar rats were randomly divided into 3 groups: control, CS and ROSI. In the CS group, rats were passively exposed to cigarette smoke for consecutive 3 months. In the ROSI group, rats were treated with rosiglitazone (3 mg/kg/day, ip) during CS exposure period. Alveolar macrophages of rats were isolated and cultured with CSE. The slices of lung tissues were stained with hematoxylin and eosin. The histomorphology was observed to evaluate emphysema and the pulmonary function was detected. Cells in bronchoalveolar lavage fluid (BALF) were examined and the expression of cytokines TNF-α and IL-1β was detected by ELISA and qPCR. The alveolar macrophage polarization was evaluated by immunohistochemistry and flow cytometry assay in vivo and by qPCR in vitro. The protein level of PPARγ and RXRα was measured by Western blot.

RESULTS

CS exposure induced significant emphysema, diminished FEV0.2/FVC, elevated PEF, and higher level of total cells, neutrophils and cytokines (TNF-α and IL-1β) in BALF compared with control group, whereas rosiglitazone partly ameliorated above disorders. CS exposure activated M1 and M2 macrophage polarization in vivo and in vitro, whereas rosiglitazone inhibited CS induced M1 macrophage polarization and decreased the ratio of M1/M2. The effects of rosiglitazone on macrophage polarization were partly blocked after AMs treated with the antagonists of PPARγ and RXRα, and were synergistically enhanced by the agonist of RXRα. CS exposure decreased the expression of PPARγ and RXRα in lung tissues and AMs, and rosiglitazone partly reversed CS-mediated suppression of PPARγ and RXRα.

CONCLUSION

Rosiglitazone ameliorated the emphysema and inflammation in lung tissues induced by CS exposure via inhibiting the M1 macrophage polarization through activating PPARγ and RXRα.

Pulmonary surfactant-associated protein B regulates prostaglandin-endoperoxide synthase-2 and inflammation in chronic obstructive pulmonary disease

NEW FINDINGS

What is the central question of this study? It is reported that polymorphism of the gene for pulmonary surfactant-associated protein B (SFTPB) is associated with chronic obstructive pulmonary disease (COPD): what are the function and mechanism of action of SFTPB in COPD? What is the main finding and its importance? Under stimulation of the risk factors of COPD, SFTPB expression is decreased, which may be involved in the formation of COPD. The progress of COPD induces an inflammatory response and reduces SFTPB expression. Levels of prostaglandin-endoperoxide synthase-2 (PTGS2) and inflammatory responses are changed by SFTPB, which indicates that SFTPB promotes the progression of COPD by PTGS2 and inflammation.

ABSTRACT

Pulmonary surfactant-associated protein B (SFTPB) is a critical protein for lung homeostasis, and polymorphism of its gene is associated with chronic obstructive pulmonary disease (COPD). However, few studies have so far confirmed the functional involvement of SFTPB in COPD. Serum SFTPB and inflammatory cytokine levels were measured in 54 patients with acute exacerbation of COPD and 29 healthy controls. A549 cells were induced using 10% cigarette smoke extract (CSE) and treated with dexamethasone to investigate the effect of inflammation on SFTPB expression, and the effect of SFTPB overexpression and silencing on inflammatory cytokines was measured using real-time PCR and enzyme-linked immunosorbent assay. SFTPB expression was assessed in mouse lung tissues using immunofluorescence. Serum levels of SFTPB were significantly lower in COPD patients than in controls (P = 0.009). Conversely, levels of interleukin (IL)-6 and prostaglandin-endoperoxide synthase-2 (PTGS2) were increased in COPD patients (IL-6: P = 0.006; PTGS2: P = 0.043). After CSE treatment, SFTPB mRNA and protein levels were significantly decreased compared to controls (mRNA: P = 0.002; protein: P = 0.011), while IL-6, IL-8 and PTGS2 were elevated. Dexamethasone treatment increased SFTPB levels. Following overexpression of SFTPB in A549 cells, mRNA and protein levels of IL-6, IL-8 and PTGS2 were significantly reduced, while gene silencing induced the opposite effect. SFTPB levels were significantly reduced in the lung tissue of a mouse model of COPD compared to controls. Reduced SFTPB levels may induce PTGS2 and inflammatory responses in COPD and SFTPB could be a key protein for evaluation of COPD progression.

Rhodiola crenulata extract decreases fatty acid oxidation and autophagy to ameliorate pulmonary arterial hypertension by targeting inhibiton of acylcarnitine in rats

Pulmonary arterial hypertension (PAH) is a devastating pulmonary circulation disease lacking high-efficiency therapeutics. The present study aims to decipher the therapeutic mechanism of Rhodiola crenulata, a well-known traditional chinese medicine with cardiopulmonary protection capacity, on PAH by exploiting functional lipidomics. The rat model with PAH was successfully established for first, following Rhodiola crenulata water extract (RCE) treatment, then analysis of chemical constituents of RCE was performed, additional morphologic, hemodynamic, echocardiographic measurements were examined, further targeted lipidomics assay was performed to identify differential lipidomes, at last accordingly mechanism assay was done by combining qRT-PCR, Western blot and ELISA. Differential lipidomes were identified and characterized to differentiate the rats with PAH from healthy controls, mostly assigned to acylcarnitines, phosphatidylcholines, sphingomyelin associated with the PAH development. Excitingly, RCE administration reversed high level of decadienyl-L-carnitine by the modulation of metabolic enzyme CPT1A in mRNA and protein level in serum and lung in the rats with PAH. Furthermore, RCE was observed to reduce autophagy, confirmed by significantly inhibited PPARγ, LC3B, ATG7 and upregulated p62, and inactivated LKB1-AMPK signal pathway. Notably, we accurately identified the constituents in RCE, and delineated the therapeutic mechansim that RCE ameliorated PAH through inhibition of fatty acid oxidation and autophagy. Altogether, RCE might be a potential therapeutic medicine with multi-targets characteristics to prevent the progression of PAH. This novel findings pave a critical foundation for the use of RCE in the treatment of PAH.