| First Author | Lalancette-Hébert M | Year | 2012 |
| Journal | J Neurosci | Volume | 32 |
| Issue | 30 | Pages | 10383-95 |
| PubMed ID | 22836271 | Mgi Jnum | J:186539 |
| Mgi Id | MGI:5432616 | Doi | 10.1523/JNEUROSCI.1498-12.2012 |
| Citation | Lalancette-Hebert M, et al. (2012) Galectin-3 is required for resident microglia activation and proliferation in response to ischemic injury. J Neurosci 32(30):10383-95 |
| abstractText | Growing evidence suggests that galectin-3 is involved in fine tuning of the inflammatory responses at the periphery, however, its role in injured brain is far less clear. Our previous work demonstrated upregulation and coexpression of galectin-3 and IGF-1 in a subset of activated/proliferating microglial cells after stroke. Here, we tested the hypothesis that galectin-3 plays a pivotal role in mediating injury-induced microglial activation and proliferation. By using a galectin-3 knock-out mouse (Gal-3KO), we demonstrated that targeted disruption of the galectin-3 gene significantly alters microglia activation and induces approximately 4-fold decrease in microglia proliferation. Defective microglia activation/proliferation was further associated with significant increase in the size of ischemic lesion, approximately 2-fold increase in the number of apoptotic neurons, and a marked deregulation of the IGF-1 levels. Next, our results revealed that contrary to WT cells, the Gal3-KO microglia failed to proliferate in response to IGF-1. Moreover, the IGF-1-mediated mitogenic microglia response was reduced by N-glycosylation inhibitor tunicamycine while coimmunoprecipitation experiments revealed galectin-3 binding to IGF-receptor 1 (R1), thus suggesting that interaction of galectin-3 with the N-linked glycans of receptors for growth factors is involved in IGF-R1 signaling. While the canonical IGF-1 signaling pathways were not affected, we observed an overexpression of IL-6 and SOCS3, suggesting an overactivation of JAK/STAT3, a shared signaling pathway for IGF-1/IL-6. Together, our findings suggest that galectin-3 is required for resident microglia activation and proliferation in response to ischemic injury. |
