Modeling Endothelial Dysfunction in Idiopathic Pulmonary Fibrosis: Bridging Mechanistic Insights and Translational Applications

bioRxiv (Cold Spring Harbor Laboratory)

Abstract

Abstract The alveolus, the lung’s primary gas exchange unit, relies on tightly coordinated interactions between epithelial and endothelial layers. In idiopathic pulmonary fibrosis (IPF), a progressive interstitial lung disease, this architecture is profoundly disrupted. While epithelial and mesenchymal compartments have been extensively studied, the role of pulmonary microvascular endothelial cells (PMVECs) in IPF pathogenesis remains underexplored. Here, we characterize PMVEC alterations in IPF using single-cell RNA sequencing and spatial transcriptomics, identifying subtype-specific markers and demonstrating their progressive loss in fibrotic lungs. To model endothelial dysfunction, we established robust protocols for isolating and culturing primary human ECs and applied a pharmacologically relevant cytokine cocktail (IPF-RC) that mimics the IPF microenvironment. IPF-RC exposure induced hallmark features of endothelial injury, including VE-cadherin loss, increased ICAM1/VCAM1 signaling, impaired barrier integrity, and reduced wound healing and angiogenic capacity. To address the need for translational tools in drug discovery, we optimized and validated a suite of functional, scalable test systems and their endpoints using both primary and commercial endothelial cells. These mechanistic assays reliably recapitulate fibrotic endothelial injury and enable quantitative assessment of therapeutic interventions. Notably, treatment with a cAMP analog partially restored endothelial function, supporting the utility of these models for regenerative and pharmacological screening. Our findings position PMVECs as active participants in IPF progression and present novel, scalable test systems that bridge mechanistic insight with translational application. These models offer a valuable platform for identifying endothelial-targeted therapies aimed at restoring alveolar capillary integrity in fibrotic lung disease.

Authors 14

1. Annalena Branz

   Boehringer Ingelheim (Germany)

   Affiliation as printed

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma

2. Irina Shalashova

   Boehringer Ingelheim (Germany)

   Affiliation as printed

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma

3. Anastasia M. Funk

   Boehringer Ingelheim (Germany)

   Affiliation as printed

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma

4. Tarek Gensheimer

   Boehringer Ingelheim (Germany)

   Affiliation as printed

   Eye Health & Research Beyond Borders, Boehringer Ingelheim Pharma;

   Eye Health & Research Beyond Borders, Boehringer Ingelheim Pharma

5. Agnieszka Wytyk

   Boehringer Ingelheim (Germany)

   Affiliation as printed

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma

6. Susanne L. Wespel

   Boehringer Ingelheim (Germany) · Universität Ulm

   Affiliation as printed

   Institute of General Physiology, Ulm University, Ulm, Germany;

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma

7. Jochen Drescher

   Boehringer Ingelheim (Germany)

   Affiliation as printed

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma

8. Christoph H. Mayr

   Boehringer Ingelheim (Germany) · Universität Ulm

   Affiliation as printed

   Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

   Institute of General Physiology, Ulm University, Ulm, Germany

9. Lavinia Neubert

   Medizinische Hochschule Hannover · German Center for Lung Research

   Affiliation as printed

   Institute of Pathology, Hannover Medical School, Hannover, Germany / Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center of Lung Research (DZL), Germany;

   Institute of Pathology, Hannover Medical School, Hannover, Germany / Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center of Lung Research (DZL), Germany

10. Jan C. Kamp

    Medizinische Hochschule Hannover · German Center for Lung Research

    Affiliation as printed

    Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center of Lung Research (DZL), Germany / Department of Respiratory Medicine and Infectious Diseases, Hannover Medical School, Hannover, Germany;

    Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center of Lung Research (DZL), Germany / Department of Respiratory Medicine and Infectious Diseases, Hannover Medical School, Hannover, Germany

11. Mark Kühnel Aachen Department of Respiratory Medicine and Infectious Diseases Hannover Medical School

    Medizinische Hochschule Hannover · Universitätsklinikum Aachen · RWTH Aachen University

    Affiliation as printed

    Department of Respiratory Medicine and Infectious Diseases, Hannover Medical School, Hannover, Germany / Institute for Pathology, University Clinic Aachen of the RWTH Aachen, Aachen, Germany

12. Danny David Jonigk Aachen Department of Respiratory Medicine and Infectious Diseases Hannover Medical School

    Medizinische Hochschule Hannover · Universitätsklinikum Aachen · RWTH Aachen University

    Affiliation as printed

    Department of Respiratory Medicine and Infectious Diseases, Hannover Medical School, Hannover, Germany / Institute for Pathology, University Clinic Aachen of the RWTH Aachen, Aachen, Germany

13. Manfred Frick

    Universität Ulm

    Affiliation as printed

    Institute of General Physiology, Ulm University, Ulm, Germany;

    Institute of General Physiology, Ulm University, Ulm, Germany

14. Muriel Lizé corresponding

    Boehringer Ingelheim (Germany)

    Affiliation as printed

    Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma;

    Immunology & Respiratory Discovery Research, Boehringer Ingelheim Pharma