Proteomic analysis of peripheral T-lymphocytes in patients with asthma

Evaluation of common protein biomarkers involved in the pathogenesis of respiratory diseases with proteomic methods: A systematic review

AIM

Respiratory disease (RD) is one of the most common diseases characterized by lung dysfunction. Many diagnostic mechanisms have been used to identify the pathogenic agents of responsible for RD. Among these, proteomics emerges as a valuable diagnostic method for pinpointing the specific proteins involved in RD pathogenesis. Therefore, in this study, for the first time, we examined the protein markers involved in the pathogenesis of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), asthma, bronchiolitis obliterans (BO), and chemical warfare victims exposed to mustard gas, using the proteomics method as a systematic study.

MATERIALS AND METHODS

A systematic search was performed up to September 2023 on several databases, including PubMed, Scopus, ISI Web of Science, and Cochrane. In total, selected 4246 articles were for evaluation according to the criteria. Finally, 119 studies were selected for this systematic review.

RESULTS

A total of 13,806 proteins were identified, 6471 in COPD, 1603 in Asthma, 5638 in IPF, three in BO, and 91 in mustard gas exposed victims. Alterations in the expression of these proteins were observed in the respective diseases. After evaluation, the results showed that 31 proteins were found to be shared among all five diseases.

CONCLUSION

Although these 31 proteins regulate different factors and molecular pathways in all five diseases, they ultimately lead to the regulation of inflammatory pathways. In other words, the expression of some proteins in COPD and mustard-exposed patients increases inflammatory reactions, while in IPF, they cause lung fibrosis. Asthma, causes allergic reactions due to T-cell differentiation toward Th2.

Modeling the pasture-associated severe equine asthma bronchoalveolar lavage fluid proteome identifies molecular events mediating neutrophilic airway inflammation

Background: Pasture-associated severe equine asthma is a warm season, environmentally-induced respiratory disease characterized by reversible airway obstruction, persistent and non-specific airway hyper-responsiveness, and chronic neutrophilic airway inflammation. During seasonal exacerbation, signs vary from mild to life-threatening episodes of wheezing, coughing, and chronic debilitating labored breathing.

Purpose: In human asthma, neutrophilic airway inflammation is associated with more severe and steroid-refractory asthma phenotypes, highlighting a need to decipher the mechanistic basis of this disease characteristic. We hypothesize that the collective biological activities of proteins in bronchoalveolar lavage fluid (BALF) of horses with pasture-associated severe asthma predict changes in neutrophil functions that contribute to airway neutrophilic inflammation.

Methods: Using shotgun proteomics, we identified 1,003 unique proteins in cell-free BALF from six horses experiencing asthma exacerbation and six control herdmates. Contributions of each protein to ten neutrophil functions were modeled using manual biocuration to determine each protein’s net effect on the respective neutrophil functions.

Results: A total of 417 proteins were unique to asthmatic horses, 472 proteins were unique to control horses (p<0.05), and 114 proteins were common in both groups. Proteins whose biological activities are responsible for increasing neutrophil migration, chemotaxis, cell spreading, transmigration, and infiltration, which would collectively bring neutrophils to airways, were over-represented in the BALF of asthmatic relative to control horses. By contrast, proteins whose biological activities support neutrophil activation, adhesion, phagocytosis, respiratory burst, and apoptosis, which would collectively shorten neutrophil lifespan, were under-represented in BALF of asthmatic relative to control horses. Interaction networks generated using Ingenuity^® Pathways Analysis further support the results of our biocuration.

Conclusion: Congruent with our hypothesis, the collective biological functions represented in differentially expressed proteins of BALF from horses with pasture-associated severe asthma support neutrophilic airway inflammation. This illustrates the utility of systems modeling to organize functional genomics data in a manner that characterizes complex molecular events associated with clinically relevant disease.

Nitric Oxide Signaling in T Cell-Mediated Immunity

Nitric oxide (NO) is a key messenger in the pathogenesis of inflammation, linking innate and adaptive immunity. By targeting signaling molecules, NO from inducible NO synthase (iNOS) and endothelial (e)NOS affects T helper cell differentiation and the effector functions of T lymphocytes, and is a potential target for therapeutic manipulation. In this review we discuss the regulatory actions exerted by NO on T cell functions, focusing on S-nitrosylation as an important post-translational modification by which NO acts as a signaling molecule during T cell-mediated immunity. We also present recent findings showing novel mechanisms through which NO regulates the activation of human T cells, and consider their potential in strategies to treat tumoral, allergic, and autoimmune diseases.

Proteomic approaches by SELDI and MALDI-TOF/MS for CTL analysis

Extracellular stimuli activate, on target cells, a number of signal transduction processes regulating gene expression and the function and/or synthesis of the proteins. In order to highlight the slight changes of the quantity and quality of the proteome it is essential to optimize preparative strategies able to improve the signals of the less expressed proteins and to standardize the use of high-throughput techniques useful to detect them. We describe a complete workflow useful to enrich, from PBMC protein extracts and extrapolated to their subpopulations, the low-molecular-weight proteins and peptides and to detect them by SELDI-TOF protein profiling. The described protocol can also be applied to MALDI-TOF/MS instruments in order to obtain fast, reproducible, and high-quality protein profiles.

Allergic asthma biomarkers using systems approaches

Asthma is characterized by lung inflammation caused by complex interaction between the immune system and environmental factors such as allergens and inorganic pollutants. Recent research in this field is focused on discovering new biomarkers associated with asthma pathogenesis. This review illustrates updated research associating biomarkers of allergic asthma and their potential use in systems biology of the disease. We focus on biomolecules with altered expression, which may serve as inflammatory, diagnostic and therapeutic biomarkers of asthma discovered in human or experimental asthma model using genomic, proteomic and epigenomic approaches for gene and protein expression profiling. These include high-throughput technologies such as state of the art microarray and proteomics Mass Spectrometry (MS) platforms. Emerging concepts of molecular interactions and pathways may provide new insights in searching potential clinical biomarkers. We summarized certain pathways with significant linkage to asthma pathophysiology by analyzing the compiled biomarkers. Systems approaches with this data can identify the regulating networks, which will eventually identify the key biomarkers to be used for diagnostics and drug discovery.

Proteomic profiling of lymphocytes in autoimmunity, inflammation and cancer

Lymphocytes play important roles in the balance between body defense and noxious agents involved in a number of diseases, e.g. autoimmune diseases, allergic inflammation and cancer. The proteomic analyses have been applied to identify and validate disease-associated and disease-specific biomarkers for therapeutic strategies of diseases. The proteomic profiles of lymphocytes may provide more information to understand their functions and roles in the development of diseases, although proteomic approaches in lymphocytes are still limited. The present review overviewed the proteomics-based studies on lymphocytes to headlight the proteomic profiles of lymphocytes in diseases, such as autoimmune diseases, allergic inflammation and cancer, with a special focus on lung diseases. We will explore the potential significance of diagnostic biomarkers and therapeutic targets from the current status in proteomic studies of lymphocytes and discuss the value of the currently available proteomic methodologies in the lymphocytes research.

Inflammatory phenotypes underlying uncontrolled childhood asthma despite inhaled corticosteroid treatment: rationale and design of the PACMAN2 study

BACKGROUND

The diagnosis of childhood asthma covers a broad spectrum of pathological mechanisms that can lead to similarly presenting clinical symptoms, but may nonetheless require different treatment approaches. Distinct underlying inflammatory patterns are thought to influence responsiveness to standard asthma medication.

METHODS/DESIGN

The purpose of the PACMAN2 study is to identify inflammatory phenotypes that can discriminate uncontrolled childhood asthma from controlled childhood asthma by measures in peripheral blood and exhaled air. PACMAN2 is a nested, case-control follow-up study to the ongoing pharmacy-based "Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects" (PACMAN) study. The original PACMAN cohort consists of children aged 4-12 years with reported use of asthma medication. The PACMAN2 study will be conducted within the larger PACMAN cohort, and will focus on detailed phenotyping of a subset of the PACMAN children. The selected participants will be invited to a follow-up visit in a clinical setting at least six months after their baseline visit based on their adherence to usage of inhaled corticosteroids, their asthma symptoms in the past year, and their age (≥ 8 years). During the follow-up visit, current and long-term asthma symptoms, medication use, environmental factors, medication adherence and levels of exhaled nitric oxide will be reassessed. The following measures will also be examined: pulmonary function, exhaled volatile organic compounds, as well as inflammatory markers in peripheral blood and blood plasma. Comparative analysis and cluster-analyses will be used to identify markers that differentiate children with uncontrolled asthma despite their use of inhaled corticosteroids (ICS) (cases) from children whose asthma is controlled by the use of ICS (controls).

DISCUSSION

Asthmatic children with distinct inflammatory phenotypes may respond differently to anti-inflammatory therapy. Therefore, by identifying inflammatory phenotypes in children with the PACMAN2 study, we may greatly impact future personalised treatment strategies, uncover new leads for therapeutic targets and improve the design of future clinical studies in the assessment of the efficacy of novel therapeutics.

HLA polymorphisms influence the development of skin rash arising from treatment with EGF receptor inhibitors

AIM

Development of a skin rash under treatment with EGF receptor (EGFR) inhibitors (EGFRIs) has been linked to a favorable prognosis in some studies, suggesting a possible immunological role for EGFRIs in addition to direct antagonistic downstream effects. The present study aimed to investigate whether particular HLA polymorphisms found in cancer patients treated with EGFRIs are associated with the development of skin rash and overall survival rates.

PATIENTS & METHODS

HLA typing was performed on 105 cancer patients and the development of skin rash was rated during the first 4 weeks of therapy with EGFRIs.

RESULTS

A significantly lower incidence of skin rash was found in patients carrying the HLA-A*02:01 or HLA-A*03:01 alleles (hazard ratio: 0.277; 95% CI: 0.121-0.634; p = 0.002 and hazard ratio: 0.292; 95% CI: 0.113-0.752; p = 0.011, respectively); however, no association with worse survival was seen.

CONCLUSION

The chances of developing a skin rash in patients treated with EGFRIs may be lower in patients that carry the HLA-A*02:01 or HLA-A*03:01 alleles, while the antitumor efficacy of EGFRIs does not seem to be significantly impaired in these patients.

Nitrosothiols in the immune system: signaling and protection

SIGNIFICANCE

In the immune system, nitric oxide (NO) has been mainly associated with antibacterial defenses exerted through oxidative, nitrosative, and nitrative stress and signal transduction through cyclic GMP-dependent mechanisms. However, S-nitrosylation is emerging as a post-translational modification (PTM) involved in NO-mediated cell signaling.

RECENT ADVANCES

Precise roles for S-nitrosylation in signaling pathways have been described both for innate and adaptive immunity. Denitrosylation may protect macrophages from their own S-nitrosylation, while maintaining nitrosative stress compartmentalized in the phagosomes. Nitrosothiols have also been shown to be beneficial in experimental models of autoimmune diseases, mainly through their role in modulating T-cell differentiation and function.

CRITICAL ISSUES

Relationship between S-nitrosylation, other thiol redox PTMs, and other NO-signaling pathways has not been always taken into account, particularly in the context of immune responses. Methods for assaying S-nitrosylation in individual proteins and proteomic approaches to study the S-nitrosoproteome are constantly being improved, which helps to move this field forward.

FUTURE DIRECTIONS

Integrated studies of signaling pathways in the immune system should consider whether S-nitrosylation/denitrosylation processes are among the PTMs influencing the activity of key signaling and adaptor proteins. Studies in pathophysiological scenarios will also be of interest to put these mechanisms into broader contexts. Interventions modulating nitrosothiol levels in autoimmune disease could be investigated with a view to developing new therapies.

Glutathione redox control of asthma: from molecular mechanisms to therapeutic opportunities

Asthma is a chronic inflammatory disorder of the airways associated with airway hyper-responsiveness and airflow limitation in response to specific triggers. Whereas inflammation is important for tissue regeneration and wound healing, the profound and sustained inflammatory response associated with asthma may result in airway remodeling that involves smooth muscle hypertrophy, epithelial goblet-cell hyperplasia, and permanent deposition of airway extracellular matrix proteins. Although the specific mechanisms responsible for asthma are still being unraveled, free radicals such as reactive oxygen species and reactive nitrogen species are important mediators of airway tissue damage that are increased in subjects with asthma. There is also a growing body of literature implicating disturbances in oxidation/reduction (redox) reactions and impaired antioxidant defenses as a risk factor for asthma development and asthma severity. Ultimately, these redox-related perturbations result in a vicious cycle of airway inflammation and injury that is not always amenable to current asthma therapy, particularly in cases of severe asthma. This review will discuss disruptions of redox signaling and control in asthma with a focus on the thiol, glutathione, and reduced (thiol) form (GSH). First, GSH synthesis, GSH distribution, and GSH function and homeostasis are discussed. We then review the literature related to GSH redox balance in health and asthma, with an emphasis on human studies. Finally, therapeutic opportunities to restore the GSH redox balance in subjects with asthma are discussed.

Proteomics in asthma and COPD phenotypes and endotypes for biomarker discovery and improved understanding of disease entities

The application of proteomics to respiratory diseases, such as asthma and COPD, has been limited compared to other fields, like cancer. Both asthma and COPD are recognised to be multi-factorial and complex diseases, both consisting of clusters of multiple disease phenotypes. The complexity of these diseases combined with the inaccessibility and invasiveness of disease relevant samples have provided a hurdle to the progress of respiratory proteomics. Advances in proteomic instrumentation and methodology have led to the possibility to identify proteomes in much smaller quantities of biological material. This review focuses on the efforts in respiratory proteomics in relation to asthma and COPD, and the importance of identifying subgroups of disease entities to establish appropriate biomarkers, and to enhance the understanding of underlying mechanisms in each subgroup. Careful phenotype characterisation of patient subpopulations is required to make improvement in the field of heterogeneous diseases such as asthma and COPD, and the clusters of phenotypes are likely to encompass subgroups of disease with distinct molecular mechanisms; endotypes. The utilisation of modern advanced proteomics in endotypes of asthma and COPD will likely contribute to the increased understanding of disease mechanisms, establishment of biomarkers for these endotypes and improved patient care.

Network analysis of quantitative proteomics on asthmatic bronchi: effects of inhaled glucocorticoid treatment

Background

Proteomic studies of respiratory disorders have the potential to identify protein biomarkers for diagnosis and disease monitoring. Utilisation of sensitive quantitative proteomic methods creates opportunities to determine individual patient proteomes. The aim of the current study was to determine if quantitative proteomics of bronchial biopsies from asthmatics can distinguish relevant biological functions and whether inhaled glucocorticoid treatment affects these functions.

Methods

Endobronchial biopsies were taken from untreated asthmatic patients (n = 12) and healthy controls (n = 3). Asthmatic patients were randomised to double blind treatment with either placebo or budesonide (800 μg daily for 3 months) and new biopsies were obtained. Proteins extracted from the biopsies were digested and analysed using isobaric tags for relative and absolute quantitation combined with a nanoLC-LTQ Orbitrap mass spectrometer. Spectra obtained were used to identify and quantify proteins. Pathways analysis was performed using Ingenuity Pathway Analysis to identify significant biological pathways in asthma and determine how the expression of these pathways was changed by treatment.

Results

More than 1800 proteins were identified and quantified in the bronchial biopsies of subjects. The pathway analysis revealed acute phase response signalling, cell-to-cell signalling and tissue development associations with proteins expressed in asthmatics compared to controls. The functions and pathways associated with placebo and budesonide treatment showed distinct differences, including the decreased association with acute phase proteins as a result of budesonide treatment compared to placebo.

Conclusions

Proteomic analysis of bronchial biopsy material can be used to identify and quantify proteins using highly sensitive technologies, without the need for pooling of samples from several patients. Distinct pathophysiological features of asthma can be identified using this approach and the expression of these features is changed by inhaled glucocorticoid treatment. Quantitative proteomics may be applied to identify mechanisms of disease that may assist in the accurate and timely diagnosis of asthma.

Trial registration

ClinicalTrials.gov registration NCT01378039

Identification of novel diagnostic biomarkers for asthma and chronic obstructive pulmonary disease

RATIONALE

Proteomics may identify a useful panel of biomarkers for identification of asthma and chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To conduct an unsupervised analysis of peripheral blood proteins in well-characterized subjects with asthma and COPD, and identify and validate a biomarker panel for disease discrimination.

METHODS

Two-dimensional difference gel electrophoresis was used to separate plasma proteins from healthy control subjects, stable patients with asthma, and individuals with COPD. Candidate protein markers were identified by matrix assisted laser desorption ionization time of flight mass spectrometry and subsequently validated in two populations via immunoassay. A panel of four biomarkers was selected and their ability to distinguish between groups was assessed in isolation and in combination in two separate validation populations.

MEASUREMENTS AND MAIN RESULTS

Seventy-two protein spots displayed significantly different expression levels between the three subject groupings (P < 0.05). Fifty-eight were positively identified, representing 20 unique proteins. A panel of four biomarkers (α(2)-macroglobulin, haptoglobin, ceruloplasmin, and hemopexin) was able to discriminate with statistical significance between the clinical groups of patients with asthma, patients with COPD, and control subjects, and these results were confirmed in a second clinical population of older adults with airflow obstruction.

CONCLUSIONS

Proteomics has identified novel biomarkers for asthma and COPD, and shown that the iron metabolism pathways and acute-phase response may be involved in the pathogenesis of airway disease. The panel of peripheral blood biomarkers has the potential to become an extremely useful addition to the clinical diagnosis and management of respiratory disease.

Proteomics in detection and monitoring of asthma and smoking-related lung diseases

Asthma, chronic obstructive pulmonary disease (COPD) and lung cancer cause extensive mortality and morbidity worldwide. However, the current state-of-the-art diagnosis and management schemes of these diseases are suboptimal as the incidence of asthma has risen by 250% over the last two decades and the 5-year mortality rate of lung cancer remains at 88%. Proteomic analysis is at the frontier of medical research and demonstrates tremendous potential in the early detection, diagnosis and staging, as well as providing novel therapeutic targets for improved management of smoking-related lung diseases. Advances in analytical tools, such as 2D gel electrophoresis, mass spectrometry, protein arrays and improved bioinformatics, allow sensitive and specific biomarker/protein profile discoveries and the infusion of new knowledge towards the molecular basis of lung diseases and their progression. Significant hurdles still stand between these laboratory findings and their applications in clinical practice. One of the challenges is the difficulty in the selection of samples that provide scope into the specific disease entity. Induced sputum, bronchoalveolar lavage, exhaled breath and exhaled breath condensate are methods of sampling airway and lung fluids that can serve as a window to assess the microenvironment of the lungs. With better study design standardization and the implementation of novel technologies to reach the optimal research standard, there is enough reason be optimistic about the future of proteomic research and its clinical implications.

Proteomic analysis of CD4+ T-lymphocytes in patients with asthma between typical therapy (controlled) and no typical therapy (uncontrolled) level

T-lymphocyte (T-LC)-derived cytokines have been implicated in asthmatic pathogenesis. Proteomic technology is now widely accepted as a complementary technology to genetic profiling. We investigated the changes of proteins in T-LC of asthmatic patients from the no typical therapy (uncontrolled) to typical therapy (controlled) level by using standard proteome technology.

METHODS

The proteins of CD4+ T-LC were isolated from the whole blood of six asthmatic patients from uncontrolled to controlled levels over 3 months. Two-dimensional polyacrylamide gel electrophoresis was performed and coomassie blue stained protein spots were comparatively analyzed by using an image analyzer. Some differentially expressed spots were identified by liquid chromatography/mass spectrometry and database search. Our results showed that 13 proteins showed different expression. Six protein spots in the CD4+ T-LC of the uncontrolled asthmatic patients were increased and 7 spots were decreased compared to those of the controlled subjects. In conclusion, the proteomic examination of the CD4+ T-LC revealed some differentially expressed proteins in the uncontrolled and controlled asthmatic patients. The possibility of using the differentially expressed proteins as important biomarkers and therapeutic targets warrants further study.

Proteomics in asthma

Proteomic approaches have already been successfully implemented in areas such as cancer research. Surprisingly, only a few proteomics analyses have been published reporting on the protein profiles associated with asthma. Although proteomics has its limitations and experimental challenges, it can successfully contribute to the understanding of a complex disease such as asthma. We have reviewed the current literature that has reported the use of proteomic techniques to identify proteins that may contribute to altered lung function in asthma. Only a few of these studies have used proteomic techniques on human tissues associated with asthma, while most research has been performed with animal models of asthma. Proteomic applications have been used as a complimentary technique to verify the suspected candidate proteins involved in asthma. In addition, novel proteins have been identified as potential therapeutic targets. Future collaboration between the different scientific disciplines using proteomic studies of animal models of asthma and confirmation of these findings in human tissues will significantly contribute to the understanding of the etiology of asthma and lead to the development of new therapeutic strategies for this highly prevalent disease.

Peripheral biomarkers of Parkinson's disease as early reporters of central neurodegeneration

Parkinson's disease (PD) is the most common age-related movement disorder, with a prevalence of approximately 2% among people over 65 years of age. The diagnosis of PD is currently based on the clinical manifestations of the disease; therefore, the availability of peripheral biomarkers would have a great impact. In this review, we discuss and compare several attempts made to find peripheral biomarkers of PD to achieve early diagnosis, differential diagnosis, therapy assessment and classification of disease subtypes. Several investigators focused on proteins that are involved in PD pathogenesis. However, the best choice for a sensible biomarker-discovery procedure makes use of global approaches such as metabolomics and proteomics. In addition, the tissue or compartment where biomarkers are located, plays a basic role. In this context, lymphocytes are of particular interest because they are circulating dopaminergic cells, and display several functional modifications in PD.

Biomarkers of lung-related diseases: current knowledge by proteomic approaches

The lung epithelial surface is one of the vital barriers or sensors in the body responding to the external atmosphere and thereby always subjecting to direct toxicological exposure, stress, stimulus, or infection. Due to its relatively higher sensitivity in response to toxicants, the use of lung epithelial cell culture and lung tissue from animal models or patients has facilitated our learning to lung physiopathology and toxicopharmacology. The recent advancement of proteomics has made it possible to investigate the cellular response at a global level. In this review, the potential applications of proteomic approach in studying lung-related diseases and biomarker discovery will be discussed.

Lymphocyte proteomics of Parkinson’s disease patients reveals cytoskeletal protein dysregulation and oxidative stress

Aims: There is increasing evidence of biochemical alterations in peripheral blood lymphocytes of Parkinson’s disease (PD) patients. In this work, we describe the changes in protein levels in peripheral lymphocytes of PD patients in order to identify potential peripheral biomarkers. Materials & methods: By means of 2D electrophoresis and mass spectrometry protein identification, we compared patients under L-3,4-dihydroxyphenylalanine (L-DOPA) treatment, patients under subthalamic nucleus deep-brain stimulation and healthy controls. Results: Statistical analysis of the results demonstrated that cofilin-1, tropomyosin, and a specific actin isoform vary significantly in patients, regardless of the therapy. Two different isoforms of γ-fibrinogen either correlate with the disease state or with the disease duration. Eventually, specific changes associated with the different therapies allowed to highlight oxidative stress conditions in lymphocytes in patients treated with higher doses of L-DOPA. Conclusions: As a whole, peripheral blood lymphocytes are sensitive reporters of PD over inter-individual variability, and allow the identification of specific alterations that could be further exploited for diagnostic purposes.

Proteomic analysis in lung tissue of smokers and COPD patients

RATIONALE

Although cigarette smoking is the most important risk factor for COPD, COPD develops in only a minority of smokers, suggesting a significant genetic role. To solve the underlying pathophysiologic mechanism, it is critical to understand genes and their final product, ie, proteins. We investigated the exclusive proteins from the lung tissues obtained from COPD patients using proteomics.

METHODS

Nontumorous lung tissue specimens were obtained from patients who underwent surgery for lung cancer. We included 22 subjects: nonsmokers (n = 8), smokers without COPD (healthy smokers, n = 7), and smokers with COPD (n = 7). Proteins were separated from their spots with two-dimensional polyacrylamide gel electrophoresis and examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). To validate the proteins from the above procedures, Western blotting and immunohistochemistry were conducted.

RESULTS

Twelve protein spots from COPD group significantly increased or decreased compared with the other two groups were chosen for MALDI-TOF-MS analysis. Eight proteins were up-regulated in the COPD group as compared with the nonsmokers. Meanwhile, five proteins from the COPD group were up-regulated and five were down-regulated when compared with healthy smokers. Of these, matrix metalloproteinase (MMP)-13 and thioredoxin-like 2 were significantly increased in the COPD patients by Western blot and immunohistochemistry. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes; however, thioredoxin-like 2 was primarily seen in the bronchial epithelium.

CONCLUSIONS

MMP-13 and thioredoxin-like 2 in lungs increased in patients with COPD. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes. In contrast, thioredoxin-like 2 was primarily seen in the bronchial epithelium.