The immunogenic role of type V collagen in the imbalance of Th17 and Treg responses in Chronic Obstructive Pulmonary Disease (COPD)

• Grant number: 24/13808-0
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2025
• End date: February 29, 2028
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Fernanda Degobbi Tenorio Quirino dos Santos Lopes
• Grantee: Fernanda Degobbi Tenorio Quirino dos Santos Lopes
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Iolanda de Fátima Lopes Calvo Tibério ; Paulo Francisco Guerreiro Cardoso ; Thais Mauad ; Walcy Paganelli Rosolia Teodoro

Abstract

There is evidence of the importance of the autoimmunity mechanism in the progression of COPD due to the chronic inflammatory process induced by exposure to cigarette smoke. As the inflammatory process progresses, the adaptive immune response mediated by Th17 lymphocytes plays an important role in this process, and its occurrence has been partly attributed to a failure in controlling the inflammatory process mediated by regulatory T lymphocytes (Treg) via the release of the anti-inflammatory interleukin IL-10. Collagen V (Col V) is a fibrillar collagen of the extracellular matrix (ECM) found in the pulmonary interstitium, incorporated into heterotypic collagen I/III fibrils. These last two types are present in greater quantities in this tissue and are therefore mainly responsible for the physical properties that determine the elasticity of this tissue. Due to its location, immunogenic, and antigenic properties, Col V is considered a sequestered antigen, remaining hidden from the immune system under normal conditions. However, in cases of tissue damage, such as ECM lung injury induced by cigarette smoke exposure due to the chronic inflammatory process, Col V epitopes can be exposed to the immune system, potentially turning them into autoantigens.Objectives: Thus, the main objective of this study is to evaluate the distribution of type V collagen concerning types I and III and its role in the imbalance of Th17 and Treg responses in COPD.Methodology: To this end, we will develop two protocols, one clinical (Protocol 1) and one experimental (Protocol 2). Protocol 1: We will conduct a retrospective study on samples from severe COPD patients who underwent lung transplantation. We will use paraffin blocks of lung tissue from these patients provided by the Pathology Service of Incor. Paraffin blocks of lung tissue from patients who died without lung disease will also be provided by the SVO service at FMUSP. This material will be prepared to make slides using the immunohistochemistry method for specific markings for the different types of collagen I, III, and V, as well as for specific cells and interleukins involved in Th17 and Treg immune responses. Quantitative evaluations of the density of the different markings per area of distal and proximal parenchyma, as well as in the peribronchovascular spaces of these patients' lungs, will be performed.Protocol 2: To better understand how the inhibition of the Th17 response may interfere with the process of lung destruction and remodeling of the different types of collagen in COPD, we will use C57/Bl 6 mice (6-8 weeks old), which will be exposed to cigarette smoke to induce COPD and will receive administration of a neutralizing antibody for IL-17 (R and D Systems, Abingdon, UK). There will be four experimental groups: Smoke Group: animals exposed to cigarette smoke, Smoke-Anti IL-17 Group: animals exposed to cigarette smoke and receiving IL-17 neutralizer administration, Control Group: animals kept under filtered ambient air, and Control-Anti IL-17 Group: animals kept under filtered ambient air and receiving IL-17 neutralizer administration. Respiratory mechanics evaluations will be performed, as well as histological analyses to verify the presence of enlargements in the distal airspaces and to quantify collagen types I, III, and V by proximal and distal parenchyma area. We will also use flow cytometry techniques to evaluate the different populations of inflammatory cells involved in Th17 and Treg responses in lung tissue homogenate. Part of these cells will also be evaluated in lung tissue through histology, in the peribronchovascular spaces, where we know there is a higher density of inflammatory cells in this experimental model. (AU)