Investigating the Pathophysiology of Pulmonary Arterial Hypertension with Organ-on-Chip Technology

• Applicant: Professor Dr. Wolfgang Kübler
• Subject Area: Anatomy and Physiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 471119131

Pulmonary arterial hypertension (PAH) is a rare cardiopulmonary disease with poor prognosis and few therapeutic options. Current therapies are based on vasodilators that can slow down, but not reverse disease progression. Loss of pulmonary capillaries (capillary rarefaction) has recently emerged as important pathomechanism of PAH, and has been linked to a translocation of lung pericytes from capillaries to remodeling arteri(ol)es. Yet, mechanisms underlying this (as well as other) process(es) of vascular remodeling in PAH remain insufficiently understood, largely because existing in vivo and in vitro models provide limited insight into the dynamics of vascular remodeling, the underlying multicellular crosstalk, and the role of the local biomechanical context. The objective of the IPACHIP project is thus to develop relevant in vitro models of the PAH lung microvasculature based on organs-on-chip (OOC) technologies, to address fundamental mechanistic questions in PAH. Two OOC models will be developed: VASC-1 is based on our existing microfluidic platform for microvascular self-assembly and VASC-2 is a more complex distal lung vasculature-on-chip model that in addition to a self-assembling capillary network includes inflow and outflow vessels. In VASC-2 relevant bio-mechanical and -chemical cues (shear stress, respiratory motions, hypoxia) will further be reproduced and controlled. Two strategies will be used to simulate PAH: 1. Models generated from primary PAH patient cells will be compared to models made from healthy donor cells, and 2. Models generated from healthy donor cells will be exposed to PAH-simulating stimuli (chronic hypoxia and/or the VEGFR antagonist SU5416). Appropriate read-outs for longitudinal assessment of vascular network parameters, cellular responses and underlying molecular mechanisms and signaling pathways will be developed by confocal and electron microscopy, immunohistochemistry, flow cytometry, molecular biology techniques, and single cell RNA sequencing. With these tools, we will assess the dynamic interaction between pericytes and endothelial cells and their role in lung microvascular network destabilization and capillary rarefaction in PAH, by focusing on:a) a potential detachment of pericytes from PAH capillaries, its underlying mechanisms and functional consequences for network integrity;b) pericyte recruitment from microvessels to precapillary arteri(ol)es in PAH;c) the role of pericyte-endothelial communication via gap junctions.The proposed work is expected to generate a unique set of novel vasculature-on-chip models for the analysis of lung vascular remodeling and its underlying mechanisms. Application of these models will yield important insights into the mechanisms driving lung capillary rarefaction with a specific emphasis on endothelial-pericyte interactions. These versatile platforms may further be used to screen for novel or repurposed drugs to halt or even reverse remodeling.

• DFG Programme: Research Grants
• International Connection: Switzerland
• Cooperation Partner: Professor Olivier Guenat, Ph.D.