Celastrol nanomedicine eye drops restore redox homeostasis and prevents keratoconus progression via PI3K/AKT/AP-1 signaling

Keratoconus (KC) is a progressive corneal disorder primarily driven by oxidative stress, though its precise molecular mechanisms remain incompletely understood, and effective pharmacological treatments are currently lacking. Our proteomic analysis of human KC tissues identified significant oxidative stress signatures and potential PI3K pathway in disease pathogenesis. Subsequent immunohistochemical and Western blot analyses confirmed a pronounced Nox/Nrf-2 redox imbalance - characterized by elevated Nox-4 and Nox-2 and suppressed Nrf-2 - along with activation of the PI3K/AKT/AP-1 signaling axis in KC corneas compared to normal corneas. To model KC-associated oxidative damage in vitro , hydrogen peroxide was used to stimulate rabbit corneal stromal cells. We developed cationic polymeric nanomicelles loaded celastrol (CPNM) to enhance corneal permeability and achieve sustain drug release. In a rabbit KC model, CPNM treatment attenuated corneal curvature progression, increased stromal thickness, and reduced ROS levels, as assessed by slit-lamp examination, histology, pachymetry, curvature measurements, and biochemical assays. Immunohistochemistry and immunofluorescence further demonstrated that CPNM downregulated PI3K/AKT/AP-1 pathway and restored Nox/Nrf-2 balance in corneal tissues. In vitro, CPNM suppressed reactive oxygen species (ROS), rebalanced the Nox/Nrf-2 system, inhibited PI3K/AKT/AP-1 activation, and reduced matrix metalloproteinase activity. Our findings indicate that CPNM prevents KC progression by concurrently inhibiting oxidative stress via Nox/Nrf-2 balance and suppressing extracellular matrix degradation via PI3K/AKT/AP-1 signaling axis, positioning it as a promising clinical treatment strategy to halt KC progression. • A celastrol nanomedicine (CPNM) eye drop was successfully fabricated and first applicated for keratoconus (KC). • Human KC proteomics reveals oxidative stress and ECM degradation co-pathology. • CPNM suppresses ROS, restores Nox/Nrf-2 balance, blocks PI3K/AKT/AP-1, and reduces MMPs in vitro. • Topical CPNM reduces Km progression, increases CCT, and diminishes opacity in rabbit KC model. • CPNM robustly halts KC progression through dual antioxidative-antifibrotic actions.