Piezo1 Activates an Autocrine Angiopoietin-2-Integrin Signaling Loop in Schlemm’s Canal to Regulate Intraocular Pressure

Abstract Elevated intraocular pressure (IOP), driven by increased outflow resistance in the trabecular meshwork and Schlemm’s canal (SC), is a primary risk factor for glaucoma. This resistance is regulated by broadly active endothelial signaling systems such as ANGPT1-TIE2 and by dynamic flow-responsive pathways that remain poorly understood. Here, we identify a previously unrecognized, TIE2-independent, mechanosensitive ANGPT2–integrin α9β1 pathway in the SC endothelium that regulates IOP. In vitro and in vivo, we show that activation of the mechanosensory channel PIEZO1 triggers ANGPT2 secretion and promotes cell-surface clustering of integrin α9β1. Deletion of SC-expressed Piezo1 or Itga9 in mice resulted in SC narrowing, impaired flow-mediated SC endothelial proliferation, IOP elevation and glaucoma. Furthermore, ANGPT2 deficiency or blockade disrupted PIEZO1-induced integrin activation and reduced aqueous humor outflow facility. These findings establish autocrine PIEZO1–ANGPT2–ITGA9 signaling as a link between mechanosensory stimuli, SC structure and IOP regulation, offering promising new targets for glaucoma therapy. Competing Interest Statement S.E.Q. is a founder of Mannin Research, a consultant for Roche and Genentech, and a member of the board of directors for AbbVie. Footnotes Funding: This work was supported by the Dr. David L. Epstein Award (to S.E.Q. and N.K.) and by NIH grant R01EY025799 (to S.E.Q.). B.R.T. received support from NIH grant R01EY032609 and BrightFocus Foundation grant M2021018N. This work was further supported by a pilot grant from the Northwestern University Center for Engineering in Vision and Ophthalmology and by an Unrestricted Departmental Grant from Research to Prevent Blindness to the Department of Ophthalmology. Competing interests: The authors declare the following competing interests: S.E.Q. is a founder of Mannin Research, a consultant for Roche and Genentech, and serves as a member of the board of directors for AbbVie. The other authors declare no competing interests. This revised version includes an updated title, expanded author list and affiliations, and revised abstract, main text, funding, competing interests, and acknowledgements. The manuscript has been substantially updated with new data and analyses, including outflow facility measurements, inducible adult Piezo1 deletion, Angpt2 deficiency and blockade experiments, TIE2 independent ANGPT2 ITGA9 FAK signaling analyses, VE cadherin junction remodeling, OCT based pRNFLT assessment, and bulk RNA seq and KEGG pathway analysis after ITGA9 knockdown. Figures and supplementary materials were reorganized and updated accordingly, including an updated mechanistic model figure. https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE168200