Genome-wide mRNA expression profiling in vastus lateralis of COPD patients with low and normal fat free mass index and healthy controls

Differentially co-expressed myofibre transcripts associated with abnormal myofibre proportion in chronic obstructive pulmonary disease

BACKGROUND

Skeletal muscle dysfunction is a common extrapulmonary manifestation of chronic obstructive pulmonary disease (COPD). Alterations in skeletal muscle myosin heavy chain expression, with reduced type I and increased type II myosin heavy chain expression, are associated with COPD severity when studied in largely male cohorts. The objectives of this study were (1) to define an abnormal myofibre proportion phenotype in both males and females with COPD and (2) to identify transcripts and transcriptional networks associated with abnormal myofibre proportion in COPD.

METHODS

Forty-six participants with COPD were assessed for body composition, strength, endurance and pulmonary function. Skeletal muscle biopsies from the vastus lateralis were assayed for fibre-type distribution and cross-sectional area via immunofluorescence microscopy and RNA-sequenced to generate transcriptome-wide gene expression data. Sex-stratified k-means clustering of type I and IIx/IIax fibre proportions was used to define abnormal myofibre proportion in participants with COPD and contrasted with previously defined criteria. Single transcripts and weighted co-expression network analysis modules were tested for correlation with the abnormal myofibre proportion phenotype.

RESULTS

Abnormal myofibre proportion was defined in males with COPD (n = 29) as <18% type I and/or >22% type IIx/IIax fibres and in females with COPD (n = 17) as <36% type I and/or >12% type IIx/IIax fibres. Half of the participants with COPD were classified as having an abnormal myofibre proportion. Participants with COPD and an abnormal myofibre proportion had lower median handgrip strength (26.1 vs. 34.0 kg, P = 0.022), 6-min walk distance (300 vs. 353 m, P = 0.039) and forced expiratory volume in 1 s-to-forced vital capacity ratio (0.42 vs. 0.48, P = 0.041) compared with participants with COPD and normal myofibre proportions. Twenty-nine transcripts were associated with abnormal myofibre proportions in participants with COPD, with the upregulated NEB, TPM1 and TPM2 genes having the largest fold differences. Co-expression network analysis revealed that two transcript modules were significantly positively associated with the presence of abnormal myofibre proportions. One of these co-expression modules contained genes classically associated with muscle atrophy, as well as transcripts associated with both type I and type II myofibres, and was enriched for genetic loci associated with bone mineral density.

CONCLUSIONS

Our findings indicate that there are significant transcriptional alterations associated with abnormal myofibre proportions in participants with COPD. Transcripts canonically associated with both type I and type IIa fibres were enriched in a co-expression network associated with abnormal myofibre proportion, suggesting altered transcriptional regulation across multiple fibre types.

Musculoskeletal crosstalk in chronic obstructive pulmonary disease and comorbidities: Emerging roles and therapeutic potentials

Chronic Obstructive Pulmonary Disease (COPD) is a multifaceted respiratory disorder characterized by progressive airflow limitation and systemic implications. It has become increasingly apparent that COPD exerts its influence far beyond the respiratory system, extending its impact to various organ systems. Among these, the musculoskeletal system emerges as a central player in both the pathogenesis and management of COPD and its associated comorbidities. Muscle dysfunction and osteoporosis are prevalent musculoskeletal disorders in COPD patients, leading to a substantial decline in exercise capacity and overall health. These manifestations are influenced by systemic inflammation, oxidative stress, and hormonal imbalances, all hallmarks of COPD. Recent research has uncovered an intricate interplay between COPD and musculoskeletal comorbidities, suggesting that muscle and bone tissues may cross-communicate through the release of signalling molecules, known as "myokines" and "osteokines". We explored this dynamic relationship, with a particular focus on the role of the immune system in mediating the cross-communication between muscle and bone in COPD. Moreover, we delved into existing and emerging therapeutic strategies for managing musculoskeletal disorders in COPD. It underscores the development of personalized treatment approaches that target both the respiratory and musculoskeletal aspects of COPD, offering the promise of improved well-being and quality of life for individuals grappling with this complex condition. This comprehensive review underscores the significance of recognizing the profound impact of COPD on the musculoskeletal system and its comorbidities. By unravelling the intricate connections between these systems and exploring innovative treatment avenues, we can aspire to enhance the overall care and outcomes for COPD patients, ultimately offering hope for improved health and well-being.

HDAC9 inhibition reduces skeletal muscle atrophy and enhances regeneration in mice with cigarette smoke-induced COPD

Cigarette smoke (CS) is the major risk factor for chronic obstructive pulmonary disease (COPD), and sarcopenia is one of the significant comorbidities of COPD. However, the pathogenesis of CS-related deficient skeletal muscle regeneration has yet to be clarified. The impact of CS on myoblast differentiation was examined, and then we determined which HDAC influenced the myogenic process and muscle atrophy in vitro and in vivo. Finally, we further investigated the potential mechanisms via RNA sequencing. Long-term CS exposure activated skeletal muscle primary satellite cells (SCs) while inhibiting differentiation, and defective myogenesis was also observed in C2C12 cells treated with CS extract (CSE). The level of HDAC9 changed in vitro and in vivo in CS exposure models as well as COPD patients, as detected by bioinformatics analysis. Our data showed that CSE impaired myogenic capacity and myotube formation in C2C12 cells via HDAC9. Moreover, inhibition of HDAC9 in mice exposed to CS prevented skeletal muscle dysfunction and promoted SC differentiation. The results of RNA-Seq analysis and verification indicated that HDAC9 knockout improved muscle differentiation in CS-exposed mice, probably by acting on the AKT/mTOR pathway and inhibiting the P53/P21 pathway. More importantly, the serum of HDAC9 KO mice exposed to CS alleviated the differentiation impairment of C2C12 cells caused by serum intervention in CS-exposed mice, and this effect was inhibited by LY294002 (an AKT/mTOR pathway inhibitor). These results suggest that HDAC9 plays an essential role in the defective regeneration induced by chronic exposure to CS.

Tenascin-C Activation of Lung Fibroblasts in a 3D Synthetic Lung Extracellular Matrix Mimic

The lung extracellular matrix (ECM) maintains the structural integrity of the tissue and regulates the phenotype and functions of resident fibroblasts. Lung-metastatic breast cancer alters these cell-ECM interactions, promoting fibroblast activation. There is a need for bio-instructive ECM models that match the ECM composition and biomechanics of the lung to study these cell-matrix interactions in vitro. Here, a synthetic, bioactive hydrogel is synthesized that mimics the native lung modulus and includes a representative distribution of the most abundant ECM peptide motifs responsible for integrin-binding and matrix metalloproteinase (MMP)-mediated degradation in the lung, which enables quiescent culture of human lung fibroblasts (HLFs). Stimulation with transforming growth factor β1 (TGF-β1), metastatic breast cancer conditioned media (CM), or tenascin-C-derived integrin-binding peptide activated hydrogel-encapsulated HLFs demonstrates multiple environmental methods to activate HLFs in a lung ECM-mimicking hydrogel. This lung hydrogel platform is a tunable, synthetic approach to studying the independent and combinatorial effects of ECM in regulating fibroblast quiescence and activation.

Mesenchymal stromal cells and alpha-1 antitrypsin have a strong synergy in modulating inflammation and its resolution

Rationale: Trauma, surgery, and infection can cause severe inflammation. Both dysregulated inflammation intensity and duration can lead to significant tissue injuries, organ dysfunction, mortality, and morbidity. Anti-inflammatory drugs such as steroids and immunosuppressants can dampen inflammation intensity, but they derail inflammation resolution, compromise normal immunity, and have significant adverse effects. The natural inflammation regulator mesenchymal stromal cells (MSCs) have high therapeutic potential because of their unique capabilities to mitigate inflammation intensity, enhance normal immunity, and accelerate inflammation resolution and tissue healing. Furthermore, clinical studies have shown that MSCs are safe and effective. However, they are not potent enough, alone, to completely resolve severe inflammation and injuries. One approach to boost the potency of MSCs is to combine them with synergistic agents. We hypothesized that alpha-1 antitrypsin (A1AT), a plasma protein used clinically and has an excellent safety profile, was a promising candidate for synergism. Methods: This investigation examined the efficacy and synergy of MSCs and A1AT to mitigate inflammation and promote resolution, using in vitro inflammatory assay and in vivo mouse acute lung injury model. The in vitro assay measured cytokine releases, inflammatory pathways, reactive oxygen species (ROS), and neutrophil extracellular traps (NETs) production by neutrophils and phagocytosis in different immune cell lines. The in vivo model monitored inflammation resolution, tissue healing, and animal survival. Results: We found that the combination of MSCs and A1AT was much more effective than each component alone in i) modulating cytokine releases and inflammatory pathways, ii) inhibiting ROS and NETs production by neutrophils, iii) enhancing phagocytosis and, iv) promoting inflammation resolution, tissue healing, and animal survival. Conclusion: These results support the combined use of MSCs, and A1AT is a promising approach for managing severe, acute inflammation.

Study of Immune Response and Malondialdehyde Levels in Irradiated Rats Supplemented with Curcuma xanthorriza Roxb Extract

OBJECTIVE

The purpose of this study was to assess the immune response and malondialdehyde levels in irradiated rats supplemented with Curcuma xanthorriza Roxb extract as a candidate for mitigating radiation exposure.

METHODS

Twenty-four male Wistar rats were grouped into eight treatment groups, then Curcuma xanthorrhiza Roxb extract was administered orally and irradiated at 6 Gy. Measurement of rats IL-6 and INF-γ was performed using a sandwich ELISA Kit, while the MDA concentration was quantified according to the method of Wills (1971). The statistical test is determined by one way ANOVA test. P-value <0.05 was considered statistically significant.

RESULT

The concentration of IL-6 in all groups showed no statistically significant difference (P=0.18). There was an increase in the concentration of IL-6 in the group of rats irradiated with 6 Gy for 7 days and 14 days. Meanwhile, the INF-γ concentration also showed no significant results in all treatment groups (P=0.28). The average of MDA concentration showed a significant difference in the liver and spleen of irradiated rats at 6 Gy for 14 days compared to the control (0.044 nmol/mg vs 0.008 nmol/mg, P=0.03 and 0.032 nmol/mg vs 0.014 nmol/mg, P=0.05, respectively).

CONCLUSION

The administration of Curcuma xanthorriza Xorb extract was able to reduce MDA concentrations in the liver and spleen although not statistically significant. In addition, exposure to ionizing radiation at a dose of 6 Gy significantly increased lipid peroxidation in the liver and spleen by 5.5 times and 2.3 times, respectively.

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.

Protective effect of berberine against LPS-induced injury in the intestine: a review

Sepsis is a systemic inflammatory condition caused by an unbalanced immunological response to infection, which affects numerous organs, including the intestines. Lipopolysaccharide (LPS; also known as endotoxin), a substance found in Gram-negative bacteria, plays a major role in sepsis and is mostly responsible for the disease's morbidity and mortality. Berberine is an isoquinoline alkaloid found in a variety of plant species that has anti-inflammatory properties. For many years, berberine has been used to treat intestinal inflammation and infection. Berberine has been reported to reduce LPS-induced intestinal damage. The potential pathways through which berberine protects against LPS-induced intestinal damage by inhibiting NF-κB, suppressing MAPK, modulating ApoM/S1P pathway, inhibiting COX-2, modulating Wnt/Beta-Catenin signaling pathway, and/or increasing ZIP14 expression are reviewed.Abbreviations: LPS, lipopolysaccharide; TLR, Toll-like receptor; MD-2, myeloid differentiation factor 2; CD14, cluster of differentiation 14; LBP, lipopolysaccharide-binding protein; MYD88, myeloid differentiation primary response 88; NF-κB, nuclear factor kappa light-chain enhancer of activated B cells; MAPK, mitogen-activated protein kinase; IL, interleukin; TNFα, tumor necrosis factor-alpha; Caco-2, cyanocobalamin uptake by human colon adenocarcinoma cell line; MLCK, myosin light-chain kinase; TJ, tight junction; IκBα, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha; IBS, irritable bowel syndrome; ERK, extracellular signal-regulated kinase; JNK, c-Jun N-terminal kinase (JNK; GVB, gut-vascular barrier; ApoM, apolipoprotein M; S1P, sphingosine-1-phosphate; VE-cadherin, vascular endothelial cadherin; AJ, adherens junction; PV1, plasmalemma vesicle-associated protein-1; HDL, high-density lipoprotein; Wnt, wingless-related integration site; Fzd, 7-span transmembrane protein Frizzled; LRP, low-density lipoprotein receptor-related protein; TEER, transendothelial/transepithelial electrical resistance; COX-2, cyclooxygenase-2; iNOS, inducible nitric oxide synthase; IGF, insulin-like growth factor; IGFBP, insulin-like growth factor-binding protein; ZIP, Zrt-Irt-like protein; PPAR, peroxisome proliferator-activated receptors; p-PPAR, phosphorylated-peroxisome proliferator-activated receptors; ATF, activating transcription factors; SOD, superoxide dismutase; GSH-Px, glutathione peroxidase; SARA, subacute ruminal acidosis; IPEC-J2, porcine intestinal epithelial cells; ALI, acute lung injury; ARDS, acute respiratory distress syndrome.

A Cosmeceutical Topical Water-in-Oil Nanoemulsion of Natural Bioactives: Design of Experiment, in vitro Characterization, and in vivo Skin Performance Against UVB Irradiation-Induced Skin Damages

Introduction

Damage to human skin occurs either chronologically or through repetitive exposure to ultraviolet (UV) radiation, where collagen photodegradation leads to the formation of wrinkles and skin imperfections. Consequently, cosmeceutical products containing natural bioactives to restore or regenerate collagen have gained a remarkable attention as an ameliorative remedy.

Methods

This study aimed to develop and optimize collagen-loaded water-in-oil nanoemulsion (W/O NE) through a D-optimal mixture design to achieve an ideal multifunctional nanosystem containing active constituents. Vit E was included as a constituent of the formulation for its antioxidant properties to minimize the destructive impact of UV radiation. The formulated systems were characterized in terms of their globule size, optical clarity, and viscosity. An optimized system was selected and evaluated for its physical stability, in vitro wound healing properties, and in vivo permeation and protection against UV radiation. In addition, the effect of collagen-loaded NE was compared to Vit C-loaded NE and collagen-/Vit C-loaded NEs mixture as Vit C is known to enhance collagen production within the skin.

Results

The optimized NE was formulated with 25% oils (Vit E: safflower oil, 1:3), 54.635% surfactant/cosurfactant (Span 80: Kolliphor EL: Arlasolve, 1:1:1), and 20.365% water. The optimized NE loaded with either collagen or Vit C exhibited a skin-friendly appearance with boosted permeability, and improved cell viability and wound healing properties on fibroblast cell lines. Moreover, the in vivo study and histopathological investigations confirmed the efficacy of the developed system to protect the skin against UV damage. The results revealed that the effect of collagen-/Vit C-loaded NEs mixture was more pronounced, as both drugs reduced the skin damage to an extent that it was free from any detectable alterations.

Conclusion

NE formulated using Vit E and containing collagen and/or Vit C could be a promising ameliorative remedy for skin protection against UVB irradiation.

Emerging role of exosomes in the pathology of chronic obstructive pulmonary diseases; destructive and therapeutic properties

Chronic obstructive pulmonary disease (COPD) is known as the third leading cause of human death globally. Enhanced chronic inflammation and pathological remodeling are the main consequences of COPD, leading to decreased life span. Histological and molecular investigations revealed that prominent immune cell infiltration and release of several cytokines contribute to progressive chronic remodeling. Recent investigations have revealed that exosomes belonging to extracellular vesicles are involved in the pathogenesis of COPD. It has been elucidated that exosomes secreted from immune cells are eligible to carry numerous pro-inflammatory factors exacerbating the pathological conditions. Here, in this review article, we have summarized various and reliable information about the negative role of immune cell-derived exosomes in the remodeling of pulmonary tissue and airways destruction in COPD patients.

GADD45A is a protective modifier of neurogenic skeletal muscle atrophy

Neurogenic muscle atrophy is the loss of skeletal muscle mass and function that occurs with nerve injury and in denervating diseases, such as amyotrophic lateral sclerosis. Aside from prompt restoration of innervation and exercise where feasible, there are currently no effective strategies for maintaining skeletal muscle mass in the setting of denervation. We conducted a longitudinal analysis of gene expression changes occurring in atrophying skeletal muscle and identified growth arrest and DNA damage-inducible A (Gadd45a) as a gene that shows one of the earliest and most sustained increases in expression in skeletal muscle after denervation. We evaluated the role of this induction using genetic mouse models and found that mice lacking GADD45A showed accelerated and exacerbated neurogenic muscle atrophy, as well as loss of fiber type identity. Our genetic analyses demonstrate that, rather than directly contributing to muscle atrophy as proposed in earlier studies, GADD45A induction likely represents a protective negative feedback response to denervation. Establishing the downstream effectors that mediate this protective effect and the pathways they participate in may yield new opportunities to modify the course of muscle atrophy.

Role of Matricellular CCN Proteins in Skeletal Muscle: Focus on CCN2/CTGF and Its Regulation by Vasoactive Peptides

The Cellular Communication Network (CCN) family of matricellular proteins comprises six proteins that share conserved structural features and play numerous biological roles. These proteins can interact with several receptors or soluble proteins, regulating cell signaling pathways in various tissues under physiological and pathological conditions. In the skeletal muscle of mammals, most of the six CCN family members are expressed during embryonic development or in adulthood. Their roles during the adult stage are related to the regulation of muscle mass and regeneration, maintaining vascularization, and the modulation of skeletal muscle fibrosis. This work reviews the CCNs proteins' role in skeletal muscle physiology and disease, focusing on skeletal muscle fibrosis and its regulation by Connective Tissue Growth factor (CCN2/CTGF). Furthermore, we review evidence on the modulation of fibrosis and CCN2/CTGF by the renin-angiotensin system and the kallikrein-kinin system of vasoactive peptides.

Linkage of primary care prescribing records and pharmacy dispensing Records in the Salford Lung Study: application in asthma

BACKGROUND

Records of medication prescriptions can be used in conjunction with pharmacy dispensing records to investigate the incidence of adherence, which is defined as observing the treatment plans agreed between a patient and their clinician. Using prescribing records alone fails to identify primary non-adherence; medications not being collected from the dispensary. Using dispensing records alone means that cases of conditions that resolve and/or treatments that are discontinued will be unaccounted for. While using a linked prescribing and dispensing dataset to measure medication non-adherence is optimal, this linkage is not routinely conducted. Furthermore, without a unique common event identifier, linkage between these two datasets is not straightforward.

METHODS

We undertook a secondary analysis of the Salford Lung Study dataset. A novel probabilistic record linkage methodology was developed matching asthma medication pharmacy dispensing records and primary care prescribing records, using semantic (meaning) and syntactic (structure) harmonization, domain knowledge integration, and natural language feature extraction. Cox survival analysis was conducted to assess factors associated with the time to medication dispensing after the prescription was written. Finally, we used a simplified record linkage algorithm in which only identical records were matched, for a naïve benchmarking to compare against the results of our proposed methodology.

RESULTS

We matched 83% of pharmacy dispensing records to primary care prescribing records. Missing data were prevalent in the dispensing records which were not matched - approximately 60% for both medication strength and quantity. A naïve benchmarking approach, requiring perfect matching, identified one-quarter as many matching prescribing records as our methodology. Factors associated with delay (or failure) to collect the prescribed medication from a pharmacy included season, quantity of medication prescribed, previous dispensing history and class of medication. Our findings indicate that over 30% of prescriptions issued were not collected from a dispensary (primary non-adherence).

CONCLUSIONS

We have developed a probabilistic record linkage methodology matching a large percentage of pharmacy dispensing records with primary care prescribing records for asthma medications. This will allow researchers to link datasets in order to extract information about asthma medication non-adherence.

[Full transcriptome analysis of gene expression in liver of mice in a comparative study of quercetin efficiency on two obesity models]

BACKGROUND

Quercetin (Q; 3,3',4',5,7 - pentahydroxyflavone) can help alleviate the pathological effects of nutritional obesity and metabolic syndrome when taken as part of products for special dietary needs and food supplements. The mechanisms of action of Q at the genetic level are not well understood.

AIMS

To study gene expression in liver tissue of mice with alimentary and genetically determined obesity upon intake of Q with diet.

MATERIALS AND METHODS

During 46 days of the experiment on 32 male C57Bl/6J mice fed a diet with an excess of fat and fructose and 24 male genetically obese db/db mice the effect of Q in dose of 25 or 100 mg/kg of body weight was studied on differential expression of 39430 genes in mice livers by full transcriptome profiling on microchip according to the Agilent One-Color Microarray-Based Gene Expression Analysis Low Input Quick Amp Labeling protocol (version 6.8). To identify metabolic pathways (KEGGs) that were targets of Q exposure, transcriptomic data were analyzed using bioinformatics methods in an "R" environment.

RESULTS

Differences were revealed in the nature of Q supplementation action in animals with dietary induced and genetically determined obesity on a number of key metabolic pathways, including the metabolism of lipids and steroids (Saa3, Cidec, Scd1, Apoa4, Acss2, Fabp5, Car3, Acacb, Insig2 genes), amino acids and nitrogen bases (Ngef, Gls2), carbohydrates (G6pdx, Pdk4), regulation of cell growth, apoptosis and proliferation (Btg3, Cgref1, Fst, Nrep Tuba8), neurotransmission (Grin2d, Camk2b), immune system reactions (CD14i, Jchain, Ifi27l2b).

CONCLUSIONS

The data obtained help to explain the ambiguous effectiveness of Q, like other polyphenols, in the dietary treatment of various forms of obesity in humans, as well as to form a set of sensitive biomarkers that allow us to elucidate the effectiveness of minor biologically active food substances in preclinical trials of new means of metabolic correction of obesity and metabolic syndrome.

Heme metabolism genes Downregulated in COPD Cachexia

INTRODUCTION

Cachexia contributes to increased mortality and reduced quality of life in Chronic Obstructive Pulmonary Disease (COPD) and may be associated with underlying gene expression changes. Our goal was to identify differential gene expression signatures associated with COPD cachexia in current and former smokers.

METHODS

We analyzed whole-blood gene expression data from participants with COPD in a discovery cohort (COPDGene, N = 400) and assessed replication (ECLIPSE, N = 114). To approximate the consensus definition using available criteria, cachexia was defined as weight-loss > 5% in the past 12 months or low body mass index (BMI) (< 20 kg/m2) and 1/3 criteria: decreased muscle strength (six-minute walk distance < 350 m), anemia (hemoglobin < 12 g/dl), and low fat-free mass index (FFMI) (< 15 kg/m2 among women and < 17 kg/m2 among men) in COPDGene. In ECLIPSE, cachexia was defined as weight-loss > 5% in the past 12 months or low BMI and 3/5 criteria: decreased muscle strength, anorexia, abnormal biochemistry (anemia or high c-reactive protein (> 5 mg/l)), fatigue, and low FFMI. Differential gene expression was assessed between cachectic and non-cachectic subjects, adjusting for age, sex, white blood cell counts, and technical covariates. Gene set enrichment analysis was performed using MSigDB.

RESULTS

The prevalence of COPD cachexia was 13.7% in COPDGene and 7.9% in ECLIPSE. Fourteen genes were differentially downregulated in cachectic versus non-cachectic COPD patients in COPDGene (FDR < 0.05) and ECLIPSE (FDR < 0.05).

DISCUSSION

Several replicated genes regulating heme metabolism were downregulated among participants with COPD cachexia. Impaired heme biosynthesis may contribute to cachexia development through free-iron buildup and oxidative tissue damage.

The rat model of COPD skeletal muscle dysfunction induced by progressive cigarette smoke exposure: a pilot study

Background

Chronic obstructive pulmonary disease (COPD) skeletal muscle dysfunction is a prevalent malady that significantly affects patients’ prognosis and quality of life. Although the study of this disease has attracted considerable attention, a definite animal model is yet to be established. This study investigates whether smoke exposure could lead to the development of a COPD skeletal muscle dysfunction model in rats.

Methods

Sprague Dawley rats were randomly divided into model (MG, n = 8) and control groups (CG, n = 6). The MG was exposed to cigarette smoke for 16 weeks while the CG was not. The body weight and forelimb grip strength of rats were monitored monthly. The pulmonary function and the strength of tibialis anterior muscle were assessed in vitro and compared after establishing the model. The histological changes in lung and gastrocnemius muscles were observed. The expressions of interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α were detected by ELISA, while the expressions of Atrogin-1 and MuRF1 in the gastrocnemius muscle were determined by Western blotting.

Results

Smoke exposure slowly increases the body weight and forelimb grip strength of MG rats, compared to CG rats. However, it significantly decreases the pulmonary ventilation function and the skeletal muscle contractility of the MG in vitro. Histologically, the lung tissues of MG show typical pathological manifestations of emphysema, while the skeletal muscles present muscular atrophy. The expressions of IL-6, IL-8, and TNF-α in MG rats are significantly higher than those measured in CG rats. Increased levels of Atrogin-1 and MuRF1 were also detected in the gastrocnemius muscle tissue of MG.

Conclusion

Progressive smoking exposure decreases the contractile function of skeletal muscles, leading to muscular atrophy. It also increases the expressions of inflammatory and muscle protein degradation factors in COPD rats. This indicates that smoke exposure could be used to establish a COPD skeletal muscle dysfunction model in rats.

CYP1B1, VEGFA, BCL2, and CDKN1A Affect the Development of Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by poor airflow. The purpose of this study was to explore the mechanisms involved in the development of COPD.

Patients and Methods

The mRNA expression profile GSE100281, consisting of 79 COPD and 16 healthy samples, was acquired from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) between COPD samples and healthy samples were analyzed using the limma package. Functional enrichment analysis for the DEGs was carried out using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) tool. Furthermore, DEG-compound pairs were predicted using the Comparative Toxicogenomics Database. The KEGG metabolite IDs corresponding to the compounds were also obtained through the MetaboAnalyst pipeline. Based on the diffusion algorithm, the metabolite network was constructed. Finally, the expression levels of key genes were determined using quantitative PCR (qPCR).

Results

There were 594 DEGs identified between the COPD and healthy samples, including 242 upregulated and 352 downregulated genes. A total of 696 DEG-compound pairs, such as BCL2-C00469 (ethanol) and BCL2-C00389 (quercetin) pairs, were predicted. CYP1B1, VEGFA, BCL2, and CDKN1A were included in the top 10 DEG-compound pairs. Additionally, 57 metabolites were obtained. In particular, hsa04750 (inflammatory mediator regulation of TRP channels)-C00469 (ethanol) and hsa04152 (AMPK signaling pathway)-C00389 (quercetin) pairs were found in the metabolite network. The results of qPCR showed that the expression of CYP1B1, VEGFA, BCL2, and CDKN1A was consistent with that predicted using bioinformatic analysis.

Conclusion

CYP1B1, VEGFA, BCL2, and CDKN1A may play important functions in the development and progression of COPD.

The prognostic significance of weight loss in chronic obstructive pulmonary disease-related cachexia: a prospective cohort study

BACKGROUND

Cachexia is an important extra-pulmonary manifestation of chronic obstructive pulmonary disease (COPD) presenting as unintentional weight loss and altered body composition. Previous studies have focused on the relative importance of body composition compared with body mass rather than the relative importance of dynamic compared with static measures. We aimed to determine the prevalence of cachexia and pre-cachexia phenotypes in COPD and examine the associations between cachexia and its component features with all-cause mortality.

METHODS

We enrolled 1755 consecutive outpatients with stable COPD from two London centres between 2012 and 2017, stratified according to European Respiratory Society Task Force defined cachexia [unintentional weight loss >5% and low fat-free mass index (FFMI)], pre-cachexia (weight loss >5% but preserved FFMI), or no cachexia. The primary outcome was all-cause mortality. We calculated hazard ratios (HRs) using Cox proportional hazards regression for cachexia classifications (cachexia, pre-cachexia, and no cachexia) and component features (weight loss and FFMI) and mortality, adjusting for age, sex, body mass index, and disease-specific prognostic markers.

RESULTS

The prevalence of cachexia was 4.6% [95% confidence interval (CI): 3.6-5.6] and pre-cachexia 1.6% (95% CI: 1.0-2.2). Prevalence was similar across sexes but increased with worsening Global Initiative for Chronic Obstructive Pulmonary Disease spirometric stage and Medical Research Council dyspnoea score (all P < 0.001). There were 313 (17.8%) deaths over a median (interquartile range) follow-up duration 1089 (547-1704) days. Both cachexia [HR 1.98 (95% CI: 1.31-2.99), P = 0.002] and pre-cachexia [HR 2.79 (95% CI: 1.48-5.29), P = 0.001] were associated with increased mortality. In multivariable analysis, the unintentional weight loss feature of cachexia was independently associated with mortality [HR 2.16 (95% CI: 1.31-3.08), P < 0.001], whereas low FFMI was not [HR 0.88 (95% CI: 0.64-1.20), P = 0.402]. Sensitivity analyses using body mass index-specific, age-specific, and gender-specific low FFMI values found consistent findings.

CONCLUSIONS

Despite the low prevalence of cachexia and pre-cachexia, both confer increased mortality risk in COPD, driven by the unintentional weight loss component. Our data suggest that low FFMI without concurrent weight loss may not confer the poor prognosis as previously reported for this group. Weight loss should be regularly monitored in practice and may represent an important target in COPD management. We propose the incorporation of weight monitoring into national and international COPD guidance.

Keratinocyte Growth Factor-2 Is Protective in Oleic Acid-Induced Acute Lung Injury in Rats

Objective

The aim of this study was to examine the role of keratinocyte growth factor-2 (KGF-2) in oleic acid-induced acute lung injury (ALI) in rats.

Methods

 Forty-five healthy adult male Sprague Dawley rats were divided into 3 groups. Rat ALI model was established by injection of 0.01 mL/kg oleic acid into the tail vein. Rats in the control group were injected with the same amount of normal saline (NS). In the ALI + KGF-2 group, 5 mg/kg of KGF-2 was instilled into the airway of rats 72 hours before the model preparation, and the control group and the ALI model group were instilled with the same amount of NS. The lung permeability index (LPI) and lung wet/dry weight (W / D) ratios were measured 8 hours after the model preparation. The permeability of pulmonary microvascular endothelium was evaluated by Evans blue leakage test. Histopathological changes were observed under light microscope and the ALI pathology score (LIS) was calculated. Ultrastructural changes of lung tissue were observed under electron microscope. The apoptosis was detected by TUNEL assay. The expression of Claudin-5, ZO-1, and VE Cadherin in lung tissue was qualitatively and quantitatively analyzed by immunohistochemistry, Western Blot, and qRT-PCR, respectively.

Results

The ALI model group had severe lung injury and obvious pathological changes, including alveolar septal thickening and inflammatory cell infiltration. TUNEL assay showed that the apoptosis of ALI group was significantly increased. The LIS score, lung W/D ratio, LPI, and Evans blue leakage were significantly higher than those in the control group; electron microscopy showed that the alveolar-capillary barrier was severely damaged in the ALI group. Compared with the control group, the expression of Claudin-5, ZO-1, and VE cadherin in the lung tissue of the ALI model group was significantly attenuated. After pretreatment with KGF-2, the degree of lung tissue damage was significantly reduced and the pathological changes were significantly improved. TUNEL assay showed that the apoptosis of ALI group was decreased. Lung W/D ratio, LPI, and Evans blue leakage decreased; electron microscopy showed that the alveolar-capillary barrier of ALI group recovered significantly. Compared with the ALI model group, the expression of Claudin-5, ZO-1, and VE cadherin in the lung tissue of the KGF-2 pretreatment group increased.

Conclusion

The results indicate that KGF-2 may attenuate oleic acid-induced ALI in rats by maintaining the pulmonary microvascular endothelial barrier, which is an effective ALI preventive measure.

Deficiency of Stomach-Type Claudin-18 in Mice Induces Gastric Tumor Formation Independent of H pylori Infection

BACKGROUND & AIMS

Epithelial cells are joined by tight junctions (TJs) to form a cell sheet. In the stomach, epithelial cell sheet forms an essential barrier against gastric material, including gastric acid. Although the decreased expression of stomach-type claudin-18 (stCldn18), a TJ protein, is generally observed in human gastritis and gastric cancer, its pathological roles are not fully understood. We previously reported that mice lacking stCldn18 (stCldn18-/-) exhibit gastric acid leakage through TJs, which induces active gastritis at a young age. Here, we examined the gastric pathologies in mice after long-term stCldn18 deficiency.

METHODS

The gastric pathologies in stCldn18-/- mice were sequentially analyzed from youth to old age, and compared to those in humans. To examine the relationship between stCldn18 deficiency-induced gastric pathologies and Wnt-dependent tumorigenesis, we generated Wnt1-overexpressing stCldn18-/- mice.

RESULTS

StCldn18-/- mice developed chronic active gastritis at middle age, with expression of the chemoattractant CCL28. At old age, 20-30% of these mice developed gastric tumors with CXCL5 expression, indicative of EMT. In this process, spasmolytic polypeptide-expressing metaplasia (SPEM) cells appeared. Increased expressions of CD44-variants, TLR2, and CXCL5 indicated age-dependent changes in cell characteristics. Some features of the stCldn18-/- mouse gastric tumorigenesis resembled H pylori-infection-related human carcinogenesis. The gastric tumorigenesis was accelerated in Wnt1-overexpressing stCldn18-/- mice, indicating that Wnt is involved in the stCldn18-/- mouse gastric tumorigenesis.

CONCLUSIONS

StCldn18 deficiency induced gastric tumorigenesis in mice without H pylori infection. Our findings revealed that several signaling networks, including the cytokine-, stemness-, and Wnt-signaling pathways, may be activated under the stCldn18-deficiency-induced chronic active gastritis to accelerate the gastric tumorigenesis.

Prediction of microRNA and gene target from an integrated network in chronic obstructive pulmonary disease based on canonical correlation analysis

BACKGROUND:

Chronic obstructive pulmonary disease (COPD) is a complex disorder with a high mortality. The pathophysiology of COPD has not been characterized till date.

OBJECTIVE:

To identify COPD-related biomarkers by a bioinformatics analysis.

METHODS:

Here, we conducted the canonical correlation analysis to extract the potential COPD-related miRNAs and mRNAs based on the miRNA-mRNA dual expression profiling data. After identifying miRNAs and mRNAs related to COPD, we constructed an interaction network by integrating three validated miRNA-target sources. Then we expanded the network by adding miRNA-mRNA pairs, which were identified by Spearman rank correlation test. For miRNAs involved in the network, we further performed the Gene Ontology (GO) functional enrichment analysis of their targets. To validate COPD-related mRNAs involved in the network, we performed receiver operating characteristic (ROC) curve analysis and Support Vector Machine (SVM) classification on only those mRNAs that overlapped with COPD-related mRNAs of Online Mendelian Inheritance in Man (OMIM) database.

RESULTS:

The results indicate that some identified miRNAs and their targets in the constructed network might be potential biomarkers of COPD.

CONCLUSIONS:

Our study helps us to predict the potential risk biomarkers of COPD, and it can certainly help in further elucidating the genetic etiology of COPD.

COPD is accompanied by co-ordinated transcriptional perturbation in the quadriceps affecting the mitochondria and extracellular matrix

Skeletal muscle dysfunction is a frequent extra-pulmonary manifestation of Chronic Obstructive Pulmonary Disease (COPD) with implications for both quality of life and survival. The underlying biology nevertheless remains poorly understood. We measured global gene transcription in the quadriceps using Affymetrix HuGene1.1ST arrays in an unselected cohort of 79 stable COPD patients in secondary care and 16 healthy age- and gender-matched controls. We detected 1,826 transcripts showing COPD-related variation. Eighteen exhibited ≥2fold changes (SLC22A3, FAM184B, CDKN1A, FST, LINC01405, MUSK, PANX1, ANKRD1, C12orf75, MYH1, POSTN, FRZB, TNC, ACTC1, LINC00310, MYH3, MYBPH and AREG). Thirty-one transcripts possessed previous reported evidence of involvement in COPD through genome-wide association, including FAM13A. Network analysis revealed a substructure comprising 6 modules of co-expressed genes. We identified modules with mitochondrial and extracellular matrix features, of which IDH2, a central component of the mitochondrial antioxidant pathway, and ABI3BP, a proposed switch between proliferation and differentiation, represent hubs respectively. COPD is accompanied by coordinated patterns of transcription in the quadriceps involving the mitochondria and extracellular matrix and including genes previously implicated in primary disease processes.

Role of accelerated aging in limb muscle wasting of patients with COPD

Purpose

Skeletal muscle wasting is an independent predictor of health-related quality of life and survival in patients with COPD, but the complexity of molecular mechanisms associated with this process has not been fully elucidated. We aimed to determine whether an impaired ability to repair DNA damage contributes to muscle wasting and the accelerated aging phenotype in patients with COPD.

Patients and methods

The levels of phosphorylated H2AX (γH2AX), a molecule that promotes DNA repair, were assessed in vastus lateralis biopsies from 10 COPD patients with low fat-free mass index (FFMI; COPD_L), 10 with preserved FFMI and 10 age- and gender-matched healthy controls. A panel of selected markers for cellular aging processes (CDKN2A/p16^ink4a, SIRT1, SIRT6, and telomere length) were also assessed. Markers of oxidative stress and cell damage and a panel of pro-inflammatory and anti-inflammatory cytokines were evaluated. Markers of muscle regeneration and apoptosis were also measured.

Results

We observed a decrease in γH2AX expression in COPD_L, which occurred in association with a tendency to increase in CDKN2A/p16^ink4a, and a significant decrease in SIRT1 and SIRT6 protein levels. Cellular damage and muscle inflammatory markers were also increased in COPD_L.

Conclusion

These data are in keeping with an accelerated aging phenotype as a result of impaired DNA repair and dysregulation of cellular homeostasis in the muscle of COPD_L. These data indicate cellular degeneration via stress-induced premature senescence and associated inflammatory responses abetted by the senescence-associated secretory phenotype and reflect an increased expression of markers of oxidative stress and inflammation.

Landscape of transcription and long non-coding RNAs reveals new insights into the inflammatory and fibrotic response following ventilator-induced lung injury

BACKGROUND

Mechanical ventilation can cause ventilator-induced lung injury (VILI) and lung fibrosis; however, the underlying mechanisms are still not fully understood. RNA sequencing is a powerful means for detecting vitally important protein-coding transcripts and long non-coding RNAs (lncRNAs) on a genome-wide scale, which may be helpful for reducing this knowledge gap.

METHODS

Ninety C57BL/6 mice were subjected to either high tidal volume ventilation or sham operation, and then mice with ventilation were randomly allocated to periods of recovery for 0, 1, 3, 5, 7, 14, 21, or 28 days. Lung histopathology, wet-to-dry weight ratio, hydroxyproline concentration, and transforming growth factor beta 1 (TGF-β1) levels were determined to evaluate the progression of inflammation and fibrosis. To compare sham-operated lungs, and 0- and 7-day post-ventilated lungs, RNA sequencing was used to elucidate the expression patterns, biological processes, and functional pathways involved in inflammation and fibrosis.

RESULTS

A well-defined fibrotic response was most pronounced on day 7 post-ventilation. Pairwise comparisons among the sham and VILI groups showed a total of 1297 differentially expressed transcripts (DETs). Gene Ontology analysis determined that the stimulus response and immune response were the most important factors involved in inflammation and fibrosis, respectively. Kyoto Encyclopedia of Genes and Genomes analysis revealed that mechanistic target of rapamycin (mTOR), Janus kinase-signal transducer and activator of transcription (JAK/STAT), and cyclic adenosine monophosphate (cAMP) signaling were implicated in early inflammation; whereas TGF-β, hypoxia inducible factor-1 (HIF-1), Toll-like receptor (TLR), and kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways were significantly involved in subsequent fibrosis. Additionally, 332 DE lncRNAs were identified and enriched in the processes of cellular and biological regulation. These lncRNAs may potentially regulate fibrosis through signaling pathways such as wingless/integrase-1 (Wnt), HIF-1, and TLR.

CONCLUSIONS

This is the first transcriptome study to reveal all of the transcript expression patterns and critical pathways involved in the VILI fibrotic process based on the early inflammatory state, and to show the important DE lncRNAs regulated in inflammation and fibrosis. Together, the results of this study provide novel perspectives into the potential molecular mechanisms underlying VILI and subsequent fibrosis.

Can muscle protein metabolism be specifically targeted by nutritional support and exercise training in chronic obstructive pulmonary disease?

Chronic obstructive pulmonary disease (COPD) associates with several extra-pulmonary effects. Muscle dysfunction and wasting is one of the most prominent extra-pulmonary effects and contributes to exercise limitation and health related quality of life (HRQoL), morbidity as well as mortality. The loss of muscle mass is characterised by an impaired balance between protein synthesis (anabolism) and protein breakdown (catabolism) which relates to nutritional disturbances, muscle disuse and the presence of a systemic inflammation, among other factors. Current approaches to reverse skeletal muscle dysfunction and wasting attain only modest improvements. The development of new therapeutic strategies aiming at improving skeletal muscle dysfunction and wasting are needed. This requires a better understanding of the underlying molecular pathways responsible for these abnormalities. In this review we update recent research on protein metabolism, nutritional depletion as well as physical (in)activity in relation to muscle wasting and dysfunction in patients with COPD. We also discuss the role of nutritional supplementation and exercise training as strategies to re-establish the disrupted balance of protein metabolism in the muscle of patients with COPD. Future areas of research and clinical practice directions are also addressed.

Network modules uncover mechanisms of skeletal muscle dysfunction in COPD patients

Background

Chronic obstructive pulmonary disease (COPD) patients often show skeletal muscle dysfunction that has a prominent negative impact on prognosis. The study aims to further explore underlying mechanisms of skeletal muscle dysfunction as a characteristic systemic effect of COPD, potentially modifiable with preventive interventions (i.e. muscle training). The research analyzes network module associated pathways and evaluates the findings using independent measurements.

Methods

We characterized the transcriptionally active network modules of interacting proteins in the vastus lateralis of COPD patients (n = 15, FEV₁ 46 ± 12% pred, age 68 ± 7 years) and healthy sedentary controls (n = 12, age 65 ± 9  years), at rest and after an 8-week endurance training program. Network modules were functionally evaluated using experimental data derived from the same study groups.

Results

At baseline, we identified four COPD specific network modules indicating abnormalities in creatinine metabolism, calcium homeostasis, oxidative stress and inflammatory responses, showing statistically significant associations with exercise capacity (VO₂ peak, Watts peak, BODE index and blood lactate levels) (P < 0.05 each), but not with lung function (FEV₁). Training-induced network modules displayed marked differences between COPD and controls. Healthy subjects specific training adaptations were significantly associated with cell bioenergetics (P < 0.05) which, in turn, showed strong relationships with training-induced plasma metabolomic changes; whereas, effects of training in COPD were constrained to muscle remodeling.

Conclusion

In summary, altered muscle bioenergetics appears as the most striking finding, potentially driving other abnormal skeletal muscle responses.

Trial registration The study was based on a retrospectively registered trial (May 2017), ClinicalTrials.gov identifier: NCT03169270

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1405-y) contains supplementary material, which is available to authorized users.

2D-DIGE proteomic analysis of vastus lateralis from COPD patients with low and normal fat free mass index and healthy controls

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with several extra-pulmonary effects of which skeletal muscle wasting is one of the most common and contributes to reduced quality of life, increased morbidity and mortality. The molecular mechanisms leading to muscle wasting are not fully understood. Proteomic analysis of human skeletal muscle is a useful approach for gaining insight into the molecular basis for normal and pathophysiological conditions.

METHODS

To identify proteins involved in the process of muscle wasting in COPD, we searched differentially expressed proteins in the vastus lateralis of COPD patients with low fat free mass index (FFMI), as a surrogate of muscle mass (COPDL, n = 10) (FEV1 33 ± 4.3% predicted, FFMI 15 ± 0.2 Kg.m-2), in comparison to patients with COPD and normal FFMI (COPDN, n = 8) and a group of age, smoking history, and sex matched healthy controls (C, n = 9) using two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) technology, combined with mass spectrometry (MS). The effect of silencing DOT1L protein expression on markers of cell arrest was analyzed in skeletal muscle satellite cells (HSkMSCs) in vitro and assessed by qPCR and Western blotting.

RESULTS

A subset of 7 proteins was differentially expressed in COPDL compared to both COPDN and C. We found an increased expression of proteins associated with muscle homeostasis and protection against oxidative stress, and a decreased expression of structural muscle proteins and proteins involved in myofibrillogenesis, cell proliferation, cell cycle arrest and energy production. Among these was a decreased expression of the histone methyltransferase DOT1L. In addition, silencing of the DOT1L gene in human skeletal muscle satellite cells in vitro was significantly related to up regulation of p21 WAF1/Cip1/CDKN1A, a marker of cell arrest and ageing.

CONCLUSIONS

2D-DIGE coupled with MS identified differences in the expression of several proteins in the wasted vastus lateralis that are relevant to the disease process. Down regulation of DOT1L in the vastus lateralis of COPDL patients may mediate the muscle wasting process through up regulation of markers of cell arrest and senescence.

Identification of potential COPD genes based on multi-omics data at the functional level

A novel systematic approach MMMG (Methylation–MicroRNA–MRNA–GO) to identify potential COPD genes and their classifying performance evaluation.