Human iPSC-derived lens organoids recapitulate lens development and morphogenesis in vitro

Abstract The human lens is a transparent, avascular organ essential for focusing light and achieving visual acuity. While animal models have illuminated lens development, direct models of human lens organogenesis remain limited. We present an in vitro platform for lens morphogenesis by combining spatially patterned self-formed ectodermal autonomous multizone (SEAM) differentiation of human induced pluripotent stem cells (hiPSCs), with a lens optimised medium (LOM). Lentoids exhibited zone-specific organisation, upregulation of lens crystallins and connexins, and spatial protein localisation reflective of lens epithelial and fiber cells. LOM-treated cultures exhibited enhanced γ-crystallin expression, cadherin-mediated organisation, and capsule basement membrane deposition, alongside ultrastructural features of a maturing lens, including elongated cortical-like fibers, epithelial layering, and intercellular junctions with ball-and-socket-like interdigitations. Lentoids demonstrated self-renewing, preplacodal and presumptive lens ectodermal PAX6⁺/SIX3⁺/SOX2⁺ epithelial-like populations, which formed secondary lentoids, following activation of lens crystallin differentiation transcription factors—PROX1 and SOX1. These findings advance hiPSC-derived lens models and reveal an epithelial plasticity—offering a platform for studying ectodermal pathways, regenerative biology, and cataractogenesis. Lens differentiation requires the highest translational output to generate lifelong structural proteins, alongside a superior protein quality control system, and hiPSC-derived platforms provide a human model to study the limits of cellular differentiation and protein homeostasis.