Khandaker N. Anwar, Asha Tadepalli, Alireza Mashaghi, Ali R. Djalilian, Samaneh Ghassemi, Gaurav Agnihotri, Peiman Hematti, Reza Dana, Ilham Putra, John A. Kink, Xiang Shen, Sofiya Reshetylo, Medi Eslani, Judy Hamouie
Macrophages are crucial drivers of inflammatory corneal neovascularization and thus are potential targets for immunomodulatory therapies. We hypothesized that therapeutic use of cornea derived mesenchymal stromal cells (cMSCs) may alter the function of macrophages. We found that cMSCs can modulate the phenotype and angiogenic function of macrophages. In vitro, cMSCs induce apoptosis of macrophages while preferentially promoting a distinct CD14hiCD16hiCD163hiCD206hi immunophenotype that has significantly reduced angiogenic effects based on in vitro angiogenesis assays. In vivo, application of cMSCs to murine corneas after injury leads to reduced macrophage infiltration and higher expression of CD206 in macrophages. Macrophages co-cultured (“educated”) by cMSCs express significantly higher levels of anti-angiogenic and anti-inflammatory factors compared to control macrophages. In vivo, injured corneas treated with cMSC-educated macrophages demonstrate significantly less neovascularization compared to corneas treated with control macrophages. Knocking down the expression of PEDF in cMSCs significantly abrogates its modulating effects on macrophages, as shown by the reduced rate of apoptosis, decreased expression of sFLT-1/PEDF, and increased expression of VEGF-A in the co-cultured macrophages. Similarly, cMSCs isolated from PEDF knockout mice are less effective compared to wild type cMSCs at inhibiting macrophage infiltration when applied to wild type corneas after injury. Overall, these results demonstrate that cMSCs therapeutically suppress the angiogenic capacity of macrophages and highlight the role of cMSC secreted PEDF in the modulation of macrophage phenotype and function. This article is protected by copyright. All rights reserved.
In the setting of severe corneal injury or inflammation, chemokines and cytokines recruit inflammatory cells which in turn induce corneal angiogenesis via VEGF-A. Cell therapy with corneal derived MSCs could modulate this inflammation in part via PEDF by inducing apoptosis of macrophages and promoting a distinct macrophage immunophenotype (cMSC-educated macrophages - cMEMq) that secrete high levels of sFLT-1, PEDF, and TSG-6.