Modeling calcific aortic valve disease with engineered human valve tissues identifies SAMHD1 as a therapeutic target

Valvular heart disease (VHD) affects over 209 million people worldwide, with calcific aortic valve disease (CAVD) playing an increasingly dominant role. However, no effective pharmacotherapies are currently available. Existing animal or cellular models are limited by insufficient physiological relevance or lack of scalability. Here, we report for the first time engineered valvular tissues (EVTs) constructed from human induced pluripotent stem cell (hiPSC)-derived valvular interstitial cells (VICs). This model was fabricated using a three-dimension (3D) hydrogel system (fibrinogen/Matrigel/collagen I), enabling anisotropic alignment of VICs with high tissue integrity that closely mimics native valve architecture and supports tissue-level biomechanical testing. Uniquely, we engineered hiPSC-derived cardiomyocytes into myocardial tissues and assembled them with EVTs to create a biomechanically active composite tissue. This design cleverly leverages the spontaneous contraction of cardiomyocytes to provide cyclic mechanical stimulation to the engineered valve, thereby validating that mechanical stress significantly exacerbates calcification. Under calcification-inducing conditions, EVTs robustly mimic key features of CAVD, including matrix remodeling, fibrosis, RUNX2 upregulation, and hydroxyapatite deposition. Biomechanical testing confirmed increased stiffness and reduced extensibility in calcified tissues, consistent with clinical observations. Furthermore, we performed time-series transcriptomic analysis throughout the in vitro culture and calcification induction process. This analysis not only confirmed a high degree of similarity between EVTs and native valves (R > 0.8) but also revealed that EVT calcification follows an osteogenic differentiation trajectory comparable to native valve calcification. Weighted gene co-expression network analysis (WGCNA) identified six potential central regulators of calcification; through subsequent small-molecule inhibition and pharmacological intervention, we definitively validated SAMHD1 as the core regulator through inflammatory signal pathway. Recombinant SAMHD1 protein significantly reduced calcification, improved tissue elasticity, and attenuated dysfunction in both static and mechanically loaded models. Our work establishes an innovative EVTs model with quantifiable tissue mechanical properties; pioneers the integration of myocardium-valve engineered tissues to construct a self-driven, cyclically stressed myocardium-valve composite model; and identifies SAMHD1 as a highly promising therapeutic target for CAVD.