**7.1. Plasma**

Based on these considerations, the hypotheses were made that (i) identified proteins may play a role in the onset and progression of UIP and OP and (ii) fragmented gelsolins may contrib-

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease associated with the exposure to tobacco smoke. To provide new insights into its pathogenesis and to compare this disorder with COPD, Ghafouri et al. [39] analyzed BALf from a biopsy-proven case of PLCH, a COPD patient, and a healthy control. Proteins were separated by 2-DE, and their patterns were analyzed with a computerized 2-DE imaging system. If compared with the profiles of the COPD patient and the healthy control, that of PLHC patient lacked significant amounts of protective and anti-inflammatory proteins. These findings opened a new route for

Cystic fibrosis (CF) is an autosomal recessive monogenic disease caused by mutations in the gene coding for the CF transmembrane conductance regulator (CFTR) protein. The main clinical features of this disorder are progressive bronchiectasis and pancreatic exocrine insufficiency. Since airway inflammation and recurrent infections leading to respiratory failure represent the major causes of morbidity and mortality among CF patients, clinical research is mainly focused on these topics. The characterization of proteins from different sources and the study of their interactions within the lung microenvironment may be useful tools toward the identification of biomarkers for the diagnosis/prognosis of this disorder. The following

The proteomic approach based on 1-DE, MALDI-TOF-MS, and LC-ESI-MS/MS allowed Schulz et al. [40] to analyze high molecular mass proteins in induced sputum from (i) CF adults with and without acute exacerbation, (ii) CF children with stable disease and preserved lung function, and (iii) healthy adults and children (controls). The main high molecular mass proteins in sputum from all subjects investigated were MUC5B and MUC5AC, two mucins that, in exacerbated CF adults, seemed degraded and also showed increased sialylation and reduced sulfation/fucosylation. In addition, while two CF children showed mucin profiles similar to those of exacerbated CF adults, the remaining CF children had profiles comparable to those of healthy controls. Based on these observations, the authors suggested that the processes of mucin glycosylation and deg-

radation may be considered as predictive biomarkers of lung condition in CF patients.

Charro et al. [41] worked on immunodepleted sera of CF patients and of healthy CF and non-CF carriers. The combination of 2D-PAGE and shotgun LC-MS/MS showed that members of the apolipoproteins family were deregulated in CF patients, while heat shock 70 kDa protein 5

ute to the development of pulmonary fibrosis.

30 Electrophoresis - Life Sciences Practical Applications

**5.5. Pulmonary Langerhans cell histiocytosis**

a better understanding of the pathophysiology of PLCH.

subsections show recent reports on proteomic research in this field.

**6. Cystic fibrosis**

**6.1. Induced sputum**

**6.2. Serum**

To shed new light on the molecular mechanisms of COPD, Merali et al. [42] investigated the plasma proteome of 10 COPD patients and 10 healthy controls. Briefly, abundant proteins in pooled plasma from each group were immunodepleted; samples were then fractionated by 1-DE prior to ESI-MS/MS. A few proteins including acute-phase response proteins, CRP, fibrinogen, coagulation factors, and adhesion molecules were upregulated in COPD patients compared to controls. By contrast, molecules involved in protease-induced lung tissue injury and repair were downregulated.

### **7.2. Induced sputum**

In a proteomic study aimed at identifying proteins involved in COPD pathogenesis, Ohlmeier et al. [43] analyzed induced sputum of nonsmokers, smokers, and smokers with moderate COPD by cysteine-specific 2D-DIGE coupled with MS. Among other candidates, polymeric immunoglobulin receptor (PIGR), a protein involved in specific immune defense and inflammation, appeared upregulated in smokers and subjects with COPD, thus suggesting its possible role in the regulation of inflammation during COPD pathogenesis.

### **7.3. Bronchoalveolar lavage fluid**

The application of 2-DE followed by LC-MS/MS allowed Plymoth et al. [44] to investigate the global proteome of BALf from 29 light and heavy smokers and 18 never-smokers in 6–7 years of follow-up study. During this study 7 of the 29 smokers developed moderate COPD. The authors observed that, although protein components were variably expressed in individuals, inflammatory and redox proteins were unambiguously upregulated in smokers compared to never-smokers.

The comparative proteomic analysis based on 2-DE and MALDI-TOF performed by Zhang et al. [50] on serum of IPAH patients and controls identified, among other proteins showing significant changes, leucine-rich α-2-glycoprotein (LRG) as a possible specific prognostic biomarker of IPAH. 2D-DIGE coupled to MALDI-TOF-MS was used by Yeager et al. [51] to investigate the plasma proteome of IPAH children with good and poor outcome to long-term vasodilator therapy. Before and after therapy, serum amyloid A (SAA-4) was found to be fourfold lower in patients with good outcome compared to those with poor outcome, while serum amyloid P (SAP) was 1.3-fold lower prior to therapy in patients with good outcome. Since these proteins regulate circulating mononuclear phagocytes, they may contribute to the

The Role of One- and Two-Dimensional Electrophoretic Techniques in Proteomics of the Lung

http://dx.doi.org/10.5772/intechopen.75042

33

Pulmonary emboli usually arise from thrombi originating in the deep venous system of the lower extremities that travel to the lung and can lodge at the bifurcation of the main pulmonary artery or the lobar causing hemodynamic compromise. Mortality rates in patients with acute pulmonary embolism (PE) vary from 1.4 to 17.4% during the first 3 months of treatment. The causes of most early deaths are complications such as acute pulmonary arterial hypertension and right heart failure, whereas medical problems underlying PE are responsible for most late deaths. The subsections reported below describe the recent advances in PE proteomics.

To identify biomarkers useful for the risk stratification in patients with acute symptomatic PE, Insenser et al. [52] studied the plasma proteome of PE patients with low, intermediate, and high risk. 2D-DIGE was used to compare the abundance of plasma proteins in the three cohorts, and candidate protein markers were identified by MALDI-TOF. Differences among patients with different PE severities were observed in a panel of four biomarkers (haptoglobin, hemopexin, α2-macroglobulin, and Ig α-1-chain C region) involved in iron metabolism pathways and acute-phase response. Among them, the reduced concentrations of haptoglobin

A proteomic approach based on capillary electrophoresis coupled to mass spectrometry (CE-MS) was applied by von zur Mühlen et al. [53] for noninvasive identification of PE specific urinary markers of pathophysiological relevance. The analysis of urine from patients with symptoms associated with deep vein thrombosis and pulmonary embolism (DVT + PE) allowed the authors to identify 62 urinary peptides, i.e., fragments of type I collagen and a fragment of fibrinogen β-chain, whose presence in organized and acute thrombus has been demonstrated by the authors

Compared to asthma, interstitial lung disease, cystic fibrosis, and COPD, fewer articles have been published for "minor" diseases including acute respiratory distress syndrome (ARDS), high-altitude pulmonary edema (HAPE), and invasive pulmonary aspergillosis (IPA). This is, in large part, due to the lower prevalence of these disorders which results in difficulties

could be considered an accurate signal for the biochemical detection of high-risk PE.

differential response to chronic vasodilator therapy.

**8.2. Pulmonary embolism**

*8.2.1. Plasma*

*8.2.2. Urine*

using immunohistochemistry.

To elucidate putative molecular mechanisms underlying gender-based differences in the pathophysiology of COPD, Kohler et al. [45] applied 2D-DIGE coupled to nano-LC-MS to investigate the proteome of non-symptomatic smokers and smokers with COPD. The authors observed significant gender differences with a subset of 19 proteins providing a highly predictive model for classification of female non-symptomatic smokers from female smokers with COPD. Subsequent pathway analyses correlated the observed alterations to downregulation of the lysosomal pathway and upregulation of the oxidative phosphorylation pathway. No altered proteins were found in the corresponding male classification model.

An interesting research (based on 2-DE and MALDI-TOF/TOF) by Pastor et al. [46, 47] evidenced a distinct proteomic reactive oxygen species (ROS) protein signature in BALf from COPD and lung cancer patients. Their findings highlight the role of ROS proteins in the pathogenic pathways of both diseases and provide new candidate biomarkers and predictive tools for lung cancer and COPD diagnosis.
