Pharmacological Inhibition of Glutaminase 1 Attenuates Alkali-Induced Corneal Neovascularization by Modulating Macrophages

Corneal neovascularization (CoNV) in response to chemical burns is a leading cause of vision impairment. Although glutamine metabolism plays a crucial role in macrophage polarization, its regulatory effect on macrophages involved in chemical burn-induced corneal injury is not known. Here, we elucidated the connection between the reprogramming of glutamine metabolism in macrophages and the development of alkali burn-induced CoNV. Glutaminase 1 (GLS1) expression was upregulated in the mouse corneas damaged with alkali burns and was primarily located in F4/80-positive macrophages. Treatment with a selective oral GLS1 inhibitor, CB-839 (telaglenastat), significantly decreased the distribution of polarized M2 macrophages in the alkali-injured corneas and suppressed the development of CoNV. In vitro studies further demonstrated that glutamine deprivation or CB-839 treatment inhibited the proliferation, adhesion, and M2 polarization of bone marrow-derived macrophages (BMDMs) from C57BL/6J mice. CB-839 treatment markedly attenuated the secretion of proangiogenic factors, including vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor-BB (PDGF-BB) from interleukin-4- (IL-4-) regulated M2 macrophages. Our findings revealed that GLS1 inhibition or glutamine deprivation prevented alkali-induced CoNV by inhibiting the infiltration and M2 polarization of macrophages. This work suggests that pharmacological GLS1 inhibition is a feasible and effective treatment strategy for chemical burn-related CoNV in humans.