Abstract
Glucagon-like peptide-1 (GLP-1) is an endogenous gut hormone and a key regulator in maintaining glucose homeostasis by stimulating insulin secretion. Its natural cleavage product GLP-1 (9–36), which was formerly considered a “bio-inactive” metabolite mainly due to its low affinity for GLP-1 receptor, possesses unique properties such as cardiovascular protection. Little is known about the effects and mechanisms of GLP-1 (9–36) in cerebral ischemia and reperfusion injury. Here, we report that systemic application of GLP-1 (9–36) in adult mice facilitated functional recovery and reduced infarct volume, astrogliosis, and neuronal apoptosis following middle cerebral artery occlusion and reperfusion. Interestingly, these effects were still observed in GLP-1 receptor knockout (Glp-1rKO) mice but were partially reversed in insulin-like growth factor 1 (IGF-1) receptor knockdown (Igf-1rKD) mice. Primary astrocytes were cultured and subjected to oxygen-glucose deprivation/reoxygenation (OGD/R), and enzyme-linked immunosorbent assay indicated that GLP-1 (9–36) pretreatment reduces tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 levels. This effect was not diminished in Glp-1rKO astrocytes but was reversed in Igf-1rKO astrocytes, emphasizing that the anti-inflammatory effect of GLP-1 (9–36) in astrocytes is independent of GLP-1 receptor signaling and is instead mediated by IGF-1 receptor. Immunoprecipitation experiments showed that GLP-1 (9–36) directly interacts with IGF-1 receptor in astrocytes. Western blot data indicated that GLP-1 (9–36) activates IGF-1 receptor and downstream PI3K-AKT pathway in astrocytes upon OGD/R injury, which was abrogated by preincubation with IGF-1 receptor autophosphorylation inhibitor picropodophyllin. Thus, our findings suggest that GLP-1 (9–36) improved stroke outcome by reducing inflammation in astrocytes via interaction with IGF-1 receptor.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
