Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.
CNS Neurosci Ther. 2023 Dec;29(12):3802-3814. doi: 10.1111/cns.14300. Epub 2023 Jun 19.
Macrophage migration inhibitory factor (MIF) is an important mediator of neuropathology in various central nervous system (CNS) diseases. However, little is known about its inducers for production from the nerve cells, as well as the underlying regulatory mechanism. Injury-induced HIF-1α has been shown to exacerbate neuroinflammation by activating multiple downstream target molecules. It is postulated that HIF-1α is involved in the regulation of MIF following spinal cord injury (SCI).
SCI model of Sprague-Dawley rats was established by cord contusion at T8-T10. The dynamic changes of HIF-1α and MIF protein levels at lesion site of rat spinal cord were determined by Western blot. The specific cell types of HIF-1α and MIF expression were examined by immunostaining. Primary astrocytes were isolated from the spinal cord, cultured and stimulated with various agonist or inhibitor of HIF-1α for analysis of HIF-1α-mediated expression of MIF. Luciferase report assay was used to determine the relationship between HIF-1α and MIF. The Basso, Beattie, and Bresnahan (BBB) locomotor scale was used to assess the locomotor function following SCI.
The protein levels of HIF-1α and MIF at lesion site were significantly elevated by SCI. Immunofluorescence demonstrated that both HIF-1α and MIF were abundantly expressed in the astrocytes of the spinal cord. By using various agonists or inhibitors of HIF-1α, it was shown that HIF-1α sufficiently induced astrocytic production of MIF. Mechanistically, HIF-1α promoted MIF expression through interaction with MIF promoter. Inhibition of HIF-1α activity using specific inhibitor markedly reduced the protein levels of MIF at lesion site following SCI, which in turn favored for the functional recovery.
SCI-induced activation of HIF-1α is able to promote MIF production from astrocytes. Our results have provided new clues for SCI-induced production of DAMPs, which may be helpful for clinical treatment of neuroinflammation.
巨噬细胞移动抑制因子（MIF）是各种中枢神经系统（CNS）疾病神经病理学的重要介质。然而，对于神经细胞产生 MIF 的诱导剂以及潜在的调节机制知之甚少。已表明，损伤诱导的 HIF-1α 通过激活多个下游靶分子加剧神经炎症。据推测，HIF-1α 参与了脊髓损伤（SCI）后 MIF 的调节。
采用 T8-T10 脊髓打击法建立 Sprague-Dawley 大鼠 SCI 模型。通过 Western blot 测定大鼠脊髓损伤部位 HIF-1α 和 MIF 蛋白水平的动态变化。通过免疫染色检查 HIF-1α 和 MIF 表达的特定细胞类型。从脊髓分离原代星形胶质细胞，进行培养并接受各种 HIF-1α 激动剂或抑制剂刺激，以分析 HIF-1α 介导的 MIF 表达。荧光素酶报告实验用于确定 HIF-1α 和 MIF 之间的关系。采用 Basso、Beattie 和 Bresnahan（BBB）运动评分评估 SCI 后的运动功能。
SCI 使损伤部位的 HIF-1α 和 MIF 蛋白水平显著升高。免疫荧光显示，HIF-1α 和 MIF 在脊髓星形胶质细胞中大量表达。通过使用各种 HIF-1α 激动剂或抑制剂，表明 HIF-1α 足以诱导星形胶质细胞产生 MIF。从机制上讲，HIF-1α 通过与 MIF 启动子相互作用促进 MIF 表达。使用特异性抑制剂抑制 HIF-1α 活性，明显降低 SCI 后损伤部位 MIF 的蛋白水平，进而有利于功能恢复。
SCI 诱导的 HIF-1α 激活能够促进星形胶质细胞产生 MIF。我们的研究结果为 SCI 诱导 DAMPs 产生提供了新的线索，这可能有助于神经炎症的临床治疗。
