Research Therese Lapperre

Abstract

A recent Lancet commission highlighted the significant and increasing burden of chronic obstructive pulmonary disease (COPD) and the need for fundamental changes in the way we think about this disease. Currently, the diagnosis of COPD requires spirometric airway limitation (FEV1/FVC <70%). However, significant lung damage may already have occurred before abnormalities in lung function are identified. Recently, the term pre-COPD has therefore been proposed to refer to individuals without airflow obstruction, but who are at increased risk of subsequently developing COPD based on their symptoms, lung function, or structural abnormalities. Importantly, the pathophysiological mechanisms underlying pre-COPD are largely unknown. Recently, our research group demonstrated a >40% reduction of small airways in pre-COPD patients compared to healthy (smoking) controls, which was similar to established GOLD I COPD. In this project, the cellular and molecular mechanisms underlying structural abnormalities in pre-COPD will be extensively investigated, with a focus on inflammation and epithelial remodeling. A comprehensive strategy will be employed, entailing a thorough transcriptomics investigation and validation at the tissue level, complemented by functional experiments utilizing patient-derived bronchial epithelial cell cultures. Understanding early pathological changes in pre-COPD will ultimately enable earlier and improved diagnosis and therapeutic intervention in (pre-)COPD patients.

Researcher(s)

• Promoter: Lapperre Therese
• Co-promoter: Smet Annemieke
• Co-promoter: Verleden Stijn
• Fellow: Voet Hanne

Research team(s)

• Laboratory Experimental Medicine and Pediatrics (LEMP)

Project type(s)

• Research Project

Abstract

Chronic obstructive pulmonary disease (COPD) is associated with high morbidity and mortality. Acute exacerbations of COPD are heterogeneous and predominantly clustered in viral, bacterial, or eosinophilic exacerbations. Bronchial epithelial cells synthesise and release several proinflammatory mediators both constitutively and in response to these (non-)infective stimuli, thereby influencing inflammatory responses. The extend of these epithelial immunomodulatory responses may however differ with COPD disease severity and disease phenotypes. However, this has not been investigated before. In the present study we will develop in vitro human bronchial epithelial cell cultures from explant lungs from pre-COPD, mild to very severe COPD patients undergoing lobectomy or lung transplantation. Using micro-CT, in-depth characterization of ex-vivo morphology and loss of the small airways, extend of mucus plugging, and degree of emphysema will further phenotype COPD patients. Bronchial epithelial cell immunomodulatory responses to infective and non-infective triggers, including anti-viral responses and pro-inflammatory responses will be assessed in relation to disease severity (GOLD I-IV) and disease phenotypes (emphysema, mucus plugging, small airway loss). In addition, the relation between in vitro epithelial mucin expression and small airway mucus plugging will be explored. Improved understanding of these epithelial immunomodulatory responses to infective and non-infective triggers of exacerbations in relation to COPD disease severity and phenotypes may improve our understanding of COPD pathogenesis and may be important to develop targeted treatment options.

Researcher(s)

• Promoter: Lapperre Therese
• Fellow: Voet Hanne

Research team(s)

• Laboratory Experimental Medicine and Pediatrics (LEMP)

Project type(s)

• Research Project

Abstract

Volatile and semivolatile chemicals are recognised as byproducts of disease, boosting volatile analysis as paramount instrument to monitor health and disease, personalize health care and objectively establish the effect of different treatment strategies. Next to volatile organic compounds (VOCs), semivolatile compounds (SVOCS) are present in the environment and in biological matrices, but most of them need to be chemically and structurally identified and their role in health and disease is yet to be explored. In this proposal, we describe the set-up of a highend GCxGC-QTOF-MS facility for analysis of VOCs and SVOCs in biological samples like breath, blood, urine, faeces of humans and animals, and in the headspace of cells. The goal is to set up an infrastructure that allows to assess and investigate multiple biological sample types and their headspace for monitoring health and disease, to identify disease biomarkers, to intensify research on the environmental health issues of modern life, and to tackle the hurdles presently encountered in the metabolomics analysis of steroids and small organic acids. By this means, we intend to team up and complement with international volatomics research groups. In Flanders, such a specialised facility is lacking, and will be unique. It combines high sensitivity, ultralow detection limits for analysis and validation of the molecular composition of biological and headspace samples, with specific sampling devices and advanced data processing.

Researcher(s)

• Promoter: De Winter Benedicte
• Co-promoter: Covaci Adrian
• Co-promoter: Lamote Kevin
• Co-promoter: Lapperre Therese
• Co-promoter: Laukens Kris
• Co-promoter: Samson Roeland
• Co-promoter: van Meerbeeck Jan
• Co-promoter: van Nuijs Alexander
• Co-promoter: Wouters An

Research team(s)

• Laboratory Experimental Medicine and Pediatrics (LEMP)

Project type(s)

• Research Project

Abstract

Bacterial infections play an important role in many lung diseases, including infective exacerbations of chronic obstructive lung disease (COPD) or community-acquired pneumonia (CAP), one of the most frequently diagnosed diseases worldwide. In order to infect the lung, bacterial pathogens produce numerous proteases with essential functions in cell viability, physiology and virulence. For example, Elastase B of Pseudomonas aeruginosa causes extensive lung damage during pneumonia. These proteases are promising candidates as both antimicrobial drug target and biomarker for lung infection. However, the precise mechanisms in which they contribute to virulence is often unclear, hampering drug and biomarker discovery. The research topic described herein uses the power of chemical probes to understand the virulent roles of bacterial proteases, for which we currently lack the tools to determine. The selected candidate will develop highly sensitive and selective chemical probes that will report on bacterial proteases activity in infection models and patient samples. This will allow to (1) uncover yet unknown virulence functions of bacterial proteases in lung diseases, such as biofilm formation and persistence and (2) evaluate bacterial proteases as potential biomarkers for bacterial lung infections. The two major groups of chemical tools to profile protease activity are activity-based probes (ABPs) and substrate probes. ABPs are small molecules that bind covalently to the active site of target enzymes. They usually contain a recognition sequence, a detection tag and an electrophilic or photoreactive group to bind into the active site. Substrate probes typically comprise of recognition sequences flanked by reagents that generate a fluorescent readout after cleavage. The candidate will synthesize such tools based on known inhibitors or substrates of bacterial proteases produced by pathogens involved in lung diseases, such as Haemophilus influenzae or Streptococcus pneumoniae. Many lung pathogens exert a particularly virulent behaviour by persisting inside epithelial cells, allowing them to evade the human immune response and antibiotic treatment. However, the role of bacterial proteases during persistence is often unknown. Thus, the candidate will apply the new probes, after biochemical validation, in in vitro and in vivo infection models to monitor the enzyme activity during persistence (collaboration with Prof. Paul Cos). Moreover, due to their high selectivity for the respective bacterial proteases, the novel tools will be perfectly suited as activity-based diagnostics. Although diagnosis is critical in acute respiratory illness, diagnostic tests that rapidly clarify the causative pathogen are often lacking and urgently needed. Therefore, the candidate will apply the probes in samples of hospitalized patients with lung infections and evaluate them as potential activity-based diagnostic tools (collaboration with Prof. Thérèse Lapperre).

Researcher(s)

• Promoter: Augustyns Koen
• Co-promoter: Cos Paul
• Co-promoter: Lapperre Therese
• Fellow: Verma Vani

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Chronic obstructive pulmonary disease (COPD) is a common disease, characterized by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities, usually caused by cigarette smoke. The small airways form the major site of resistance within the lung and small airway destruction has been demonstrated before the onset of emphysema. Since, there are no reliable markers on pulmonary function testing or imaging, small airways are difficult to analyze in vivo. We hypothesize that an in-depth investigation of the association between the in-vivo presentation and physiology (i.e. detailed clinical characterization, pulmonary function and radiology) and ex-vivo morphology of the small airways (microCT, histopathology) will result in clinical meaningful markers of small airway dysfunction in COPD phenotypes which is important for early diagnosis and better treatment. Using an innovative approach, we will combine in vivo assessments of small airway dysfunction with morphological assessment of excised lung specimens. Patients with isolated lung nodules in whom surgical treatment by lobectomy or pneumonectomy is indicated (smoking and non-smoking controls and mild COPD GOLD I and II) and patients undergoing lung transplantation (severe GOLD III and IV) will be recruited. In parallel, we will also collect donor lungs or lobes that could not be used for lung transplantation as controls. We aim to include at least 15 patients in each group, leading to a total of 75 patients. Patients will undergo detailed assessment of their clinical phenotype, pulmonary function (including small airways function), and inspiratory and expiratory CT-thorax (degree of functional small airway disease, emphysema, mucus plugging, airtrapping and bronchiectasis). Next, the excised specimen will undergo a standardized work-up including inflation and fixation in liquid nitrogen, and will then undergo ex vivo CT (resolution of 0.6 mm) and whole lung microCT (resolution 0.1 mm) to assess the entire airway tree from the main stem bronchus till the last generation of conducting airways. Based on these scans, the degree of mucus plugging, airway obliteration and airway loss will be measured in function of the airway generation and diameter. Subsequently, different cores will be extracted. The presence of pathological airway obstruction, quantification of small airway number and dimensions, and parenchymal measures will be assessed. Furthermore, the degree of collateral ventilation, an important compensatory mechanism of small airway loss, will be determined in function of the number of small airways and the local emphysema grade by using electron microscope scanning on the very same samples. The integration of the in vivo measurements and the ex vivo direct assessment of small airway remodeling will, for the first time, demonstrate the most optimal (combination of) tools to assess small airway disease in patients. We are convinced that this multi-modal approach will be useful to identify clinically meaningful parameters of small airway remodeling, which will improve monitoring of (early) disease progression and impact of treatment interventions. In the future, this unique cohort can be further exploited to obtain biological markers in biopsies that will be concomitantly collected and to further investigate the molecular mechanisms of small airway remodeling (i.e. inflammation, fibrosis) in more detail. With this grant, we want to initiate the banking and recruitment of patients, so that there is sufficient preliminary data to apply for internal and external competitive grant funding.

Researcher(s)

• Promoter: Lapperre Therese

Research team(s)

• Laboratory Experimental Medicine and Pediatrics (LEMP)

Project type(s)

• Research Project

Abstract

Exposure to air pollution is an important public health issue and has been associated with burden of disease, and increased mortality and morbidity. However, there is no safe threshold under which no health effects occur and only associations have been found so far. The goal of this pilot project is to prove the causal relation by assessing the impact of air pollution exposure on health and respiratory functioning, by combining air pollution monitoring with lung response measurements and exhaled breath analysis in order to minimize morbidity.

Researcher(s)

• Promoter: van Meerbeeck Jan
• Co-promoter: De Winter Benedicte
• Co-promoter: Lamote Kevin
• Co-promoter: Lapperre Therese
• Co-promoter: Samson Roeland

Research team(s)

• Laboratory Experimental Medicine and Pediatrics (LEMP)

Project type(s)

• Research Project