Speakers - 2027

Title: 3D Bioprinted PAH vascular platform reveals altered mechanosensing in BMPR2 deficiency

Abstract

Objectives: Pulmonary arterial hypertension (PAH) is characterized by progressive extracellular matrix (ECM) remodeling, arterial stiffening, and dysregulated mechanotransduction that collectively drive pulmonary vascular remodeling. Although matrix stiffening and BMPR2 dysfunction are recognized as major contributors to PAH progression, current in vitro models fail to reproduce the spatial mechanical heterogeneity and architectural remodeling observed in diseased pulmonary arteries. Therefore, this study aimed to engineer a biomimetic vascular platform capable of recapitulating localized stiffness gradients, structural anisotropy, and disease-associated mechanobiological responses observed in PAH.
Methodology: A stereolithography-based multi-material bioprinting strategy was developed using GelMA–PEGDA hydrogels combined with grayscale photomask-guided photopolymerization to generate vascular scaffolds with tunable stiffness heterogeneity and aligned microarchitectures. Scaffold geometry, channel dimensions, porosity, and stiffness were optimized through modulation of methacrylation degree, photoinitiator concentration, grayscale exposure intensity, and multimaterial PEGDA reinforcement. Spatially patterned stiffness gradients within the scaffolds were confirmed using nanoindentation measurements. Healthy pulmonary arterial smooth muscle cells (PASMCs) and BMPR2 knockdown PASMCs were cultured on seven mechanically distinct scaffold groups to investigate YAP1-mediated mechanotransduction responses.

Results: The engineered constructs successfully reproduced localized mechanical heterogeneity characteristic of pulmonary vascular remodeling. Nanoindentation confirmed spatially patterned stiffness gradients ranging from healthy-like (~4–5 kPa) to diseased PAH-like (~15–28 kPa) mechanical conditions while maintaining high print fidelity and structural stability. In healthy PASMCs, YAP1 nuclear translocation was predominantly regulated by bulk scaffold stiffness, with uniformly stiff scaffolds inducing strong mechanosensitive activation. In contrast, BMPR2- deficient PASMCs demonstrated heightened sensitivity to spatial mechanical heterogeneity and architectural patterning. Grayscale-patterned heterogeneous scaffolds induced amplified YAP1 nuclear localization together with increased expression of mechanosensitive genes, including CYR61 and CTGF, compared with uniformly stiff constructs. Spatial mapping further revealed region-dependent YAP activation governed by local stiffness distribution, scaffold geometry, and alignment cues.

Conclusion: Overall, this study presents a physiologically relevant vascular model integrating multimaterial bioprinting, grayscale-mediated stiffness patterning, and BMPR2 deficiency within a single engineered system. These findings reveal that BMPR2 dysfunction shifts mechanosensing from global stiffness perception toward spatially resolved mechanical heterogeneity, providing new insight into PAH mechanobiology and establishing a scalable platform for precision disease modeling and therapeutic screening.