RT Journal Article T1 STAT3-Mediated Astrocyte Reactivity Associated with Brain Metastasis Contributes to Neurovascular Dysfunction. A1 Sarmiento Soto, Manuel A1 Larkin, James R A1 Martin, Chris A1 Khrapitchev, Alexandre A A1 Maczka, Melissa A1 Economopoulos, Vasiliki A1 Scott, Helen A1 Escartin, Carole A1 Bonvento, Gilles A1 Serres, Sébastien A1 Sibson, Nicola R AB Astrocytes are thought to play a pivotal role in coupling neural activity and cerebral blood flow. However, it has been shown that astrocytes undergo morphologic changes in response to brain metastasis, switching to a reactive phenotype, which has the potential to significantly compromise cerebrovascular function and contribute to the neurological sequelae associated with brain metastasis. Given that STAT3 is a key regulator of astrocyte reactivity, we aimed here to determine the impact of STAT3-mediated astrocyte reactivity on neurovascular function in brain metastasis. Rat models of brain metastasis and ciliary neurotrophic factor were used to induce astrocyte reactivity. Multimodal imaging, electrophysiology, and IHC were performed to determine the relationship between reactive astrocytes and changes in the cerebrovascular response to electrical and physiological stimuli. Subsequently, the STAT3 pathway in astrocytes was inhibited with WP1066 to determine the role of STAT3-mediated astrocyte reactivity, specifically, in brain metastasis. Astrocyte reactivity associated with brain metastases impaired cerebrovascular responses to stimuli at both the cellular and functional level and disrupted astrocyte-endothelial interactions in both animal models and human brain metastasis samples. Inhibition of STAT3-mediated astrocyte reactivity in rats with brain metastases restored cerebrovascular function, as shown by in vivo imaging, and limited cerebrovascular changes associated with tumor growth. Together these findings suggest that inhibiting STAT3-mediated astrocyte reactivity may confer significant improvements in neurological outcome for patients with brain metastases and could potentially be tested in other brain tumors. SIGNIFICANCE: These findings demonstrate that selectively targeting STAT3-mediated astrocyte reactivity ameliorates the cerebrovascular dysfunction associated with brain metastasis, providing a potential therapeutic avenue for improved patient outcome. YR 2020 FD 2020-10-26 LK http://hdl.handle.net/10668/16481 UL http://hdl.handle.net/10668/16481 LA en DS RISalud RD Apr 6, 2025