Meteorin is upregulated in reactive astrocytes and functions as a negative feedback effector in reactive gliosis

Reactive gliosis is a glial response to a wide range of central nervous system insults, which results in cellular and molecular changes to resting glial cells. Despite its fundamental effect on neuropathologies, the identification and characterization of the molecular mechanisms underlying this process remain to be fully elucidated. The aim of the present study was to analyze the expression profile and functions of the astrocytic neurotrophic factor, meteorin, in the progression of reactive gliosis. A mouse model of photothrombotic ischemia, and a primary astrocyte culture were used in the present study. Reverse transcription quantitative polymerase chain reaction, western blotting and immunofluorescence staining were performed to examine the expression levels of meteorin and reactive gliosis markers. Increased expression levels of meteorin were observed in reactive astrocytes in a photothrombotic ischemia mouse model, as well as in cultured astrocytes, which were stimulated by transforming growth factor-β1. Exogenous treatment of the astrocytes with meteorin did not induce janus kinase-signal transducer and activator of transcription 3 signaling, however, silencing the expression of meteorin in the astrocytes resulted in an upregulation of reactive astrocyte markers, including glial fibrillary acidic protein and S100β, indicating that endogenous meteorin is required for the maintenance of astrocytic homeostasis. These results suggested a novel role for meteorin as a negative feedback effector in reactive gliosis.