Department of Pediatrics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Region Västra Götaland, Department of Neonatology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden.
Dev Neurosci. 2021;43(5):296-311. doi: 10.1159/000517687. Epub 2021 Jun 15.
Microglia may contribute to injury but may also have neuroprotective properties. Galectin-3 has immunomodulatory properties that may affect the microglia phenotype and subsequent development of injury. Galectin-3 contributes to experimental hypoxic-ischemic (HI) injury in the neonatal brain, but it is unclear if galectin-3 has similar effects on infectious and sterile inflammation. Thus, we investigated the effect of galectin-3 on microglia in vitro under normal as well as infectious and sterile inflammatory conditions, and the effect of galectin-3 on neonatal brain injury following an infectious challenge in vivo. Conditions mimicking infectious or sterile inflammation were evaluated in primary microglia cell cultures from newborn mice, using LPS (10 ng/mL) and TNF-α (100 ng/mL). The response to galectin-3 was tested alone or together with LPS or TNF-α. Supernatants were collected 24 h after treatment and analyzed for 23 inflammatory mediators including pro- and anti-inflammatory cytokines and chemokines using multiplex protein analysis, as well as ELISA for MCP-1 and insulin-like growth factor (IGF)-1. Phosphorylation of proteins (AKT, ERK1/2, IκB-α, JNK, and p38) was determined in microglia cells. Neonatal brain injury was induced by a combination of LPS and HI (LPS + HI) in postnatal day 9 transgenic mice lacking functional galectin-3 and wild-type controls. LPS and TNF-α induced pro-inflammatory (9/11 vs. 9/10) and anti-inflammatory (6/6 vs. 2/6) cytokines, as well as chemokines (6/6 vs. 4/6) in a similar manner, except generally lower amplitude of the TNF-α-induced response. Galectin-3 alone had no effect on any of the proteins analyzed. Galectin-3 reduced the LPS- and TNF-α-induced microglia response for cytokines, chemokines, and phosphorylation of IκB-α. LPS decreased baseline IGF-1 levels, and the levels were restored by galectin-3. Brain injury or microglia response after LPS + HI was not affected by galectin-3 deficiency. Galectin-3 has no independent effect on microglia but modulates inflammatory activation in vitro. The effect was similar under infectious and sterile inflammatory conditions, suggesting that galectin-3 regulates inflammation not just by binding to LPS or toll-like receptor-4. Galectin-3 restores IGF-1 levels reduced by LPS-induced inflammation, suggesting a potential protective effect on infectious injury. However, galectin-3 deficiency did not affect microglia activation and was not beneficial in an injury model encompassing an infectious challenge.
小胶质细胞可能导致损伤，但也可能具有神经保护特性。半乳糖凝集素-3 具有免疫调节特性，可能影响小胶质细胞表型和随后的损伤发展。半乳糖凝集素-3 导致新生鼠脑缺氧缺血（HI）损伤，但尚不清楚半乳糖凝集素-3 是否对感染性和无菌性炎症有类似的影响。因此，我们研究了半乳糖凝集素-3 在正常以及感染性和无菌性炎症条件下对体外小胶质细胞的影响，以及半乳糖凝集素-3 在体内感染性挑战后对新生鼠脑损伤的影响。使用 LPS（10ng/mL）和 TNF-α（100ng/mL）在来自新生小鼠的原代小胶质细胞培养物中评估模拟感染或无菌性炎症的条件。单独或与 LPS 或 TNF-α 一起测试半乳糖凝集素-3 的反应。用多重蛋白分析以及 ELISA 法检测 MCP-1 和胰岛素样生长因子（IGF）-1，分析治疗后 24 小时收集的上清液中 23 种炎症介质，包括促炎和抗炎细胞因子和趋化因子。测定小胶质细胞中蛋白质（AKT、ERK1/2、IκB-α、JNK 和 p38）的磷酸化。在缺乏功能性半乳糖凝集素-3 的新生后 9 天转基因小鼠和野生型对照中，通过 LPS 和 HI（LPS + HI）联合诱导新生鼠脑损伤。LPS 和 TNF-α 以相似的方式诱导促炎（9/11 与 9/10）和抗炎（6/6 与 2/6）细胞因子以及趋化因子（6/6 与 4/6），但 TNF-α 诱导反应的幅度通常较低。半乳糖凝集素-3 本身对分析的任何蛋白质都没有影响。半乳糖凝集素-3 降低了 LPS 和 TNF-α 诱导的小胶质细胞细胞因子、趋化因子和 IκB-α 磷酸化反应。LPS 降低了 IGF-1 的基础水平，而半乳糖凝集素-3 则恢复了 IGF-1 的水平。LPS + HI 后的脑损伤或小胶质细胞反应不受半乳糖凝集素-3 缺乏的影响。半乳糖凝集素-3 对小胶质细胞没有独立作用，但可在体外调节炎症激活。在感染性和无菌性炎症条件下，效果相似，表明半乳糖凝集素-3 调节炎症不仅通过与 LPS 或 Toll 样受体-4 结合。半乳糖凝集素-3 恢复 LPS 诱导的炎症降低的 IGF-1 水平，提示对半乳糖凝集素-3 对感染性损伤具有潜在的保护作用。然而，半乳糖凝集素-3 缺乏并不影响小胶质细胞激活，并且在包含感染性挑战的损伤模型中没有益处。
