Unidad de Neuroinflamación, Área de Biología Celular y del Desarrollo, Unidad Funcional de Investigación en Enfermedades Crónicas, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
Glia. 2013 Jul;61(7):1052-66. doi: 10.1002/glia.22494. Epub 2013 Apr 26.
Increase in intracellular calcium ([Ca(2+) ]i ) is a key mediator of astrocyte signaling, important for activation of the calcineurin (CN)/nuclear factor of activated T cells (NFAT) pathway, a central mediator of inflammatory events. We analyzed the expression of matrix metalloproteinase 3 (Mmp3) in response to increases in [Ca(2+) ]i and the role of the CN/NFAT pathway in this regulation. Astrocyte Mmp3 expression was induced by overexpression of a constitutively active form of NFATc3, whereas other MMPs and tissue inhibitor of metalloproteinases (TIMP) were unaffected. Mmp3 mRNA and protein expression was also induced by calcium ionophore (Io) and 2'(3')-O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (Bz-ATP) and Mmp3 upregulation was prevented by the CN inhibitor cyclosporin A (CsA). Ca(2+) -dependent astrocyte Mmp3 expression was also inhibited by actinomycin D, and a Mmp3 promoter luciferase reporter was efficiently activated by increased [Ca(2+) ]i , indicating regulation at the transcriptional level. Furthermore, Ca(2+) /CN/NFAT dependent Mmp3 expression was confirmed in pure astrocyte cultures derived from neural stem cells (Ast-NSC), demonstrating that the induced Mmp3 expression occurs in astrocytes, and not microglial cells. In an in vivo stab-wound model of brain injury, MMP3 expression was detected in NFATc3-positive scar-forming astrocytes. Because [Ca(2+) ]i increase is an early event in most brain injuries, these data support an important role for Ca(2+) /CN/NFAT-induced astrocyte MMP3 expression in the early neuroinflammatory response. Understanding the molecular pathways involved in this regulation could provide novel therapeutic targets and approaches to promoting recovery of the injured brain.
细胞内钙离子浓度 ([Ca(2+) ]i ) 的增加是星形胶质细胞信号转导的关键介质，对于钙调神经磷酸酶 (CN)/活化 T 细胞核因子 (NFAT) 途径的激活至关重要，该途径是炎症事件的中央介质。我们分析了基质金属蛋白酶 3 (Mmp3) 对 [Ca(2+) ]i 增加的反应表达以及 CN/NFAT 途径在这种调节中的作用。通过过表达 NFATc3 的组成性激活形式诱导星形胶质细胞 Mmp3 的表达，而其他 MMP 和金属蛋白酶组织抑制剂 (TIMP) 不受影响。钙离子载体 (Io) 和 2'（3'）-O-(4-苯甲酰基苯甲酰基)腺苷 5'-三磷酸 (Bz-ATP) 也诱导 Mmp3 mRNA 和蛋白表达，CN 抑制剂环孢素 A (CsA) 可阻止 Mmp3 的上调。钙依赖性星形胶质细胞 Mmp3 表达也被放线菌素 D 抑制，并且增加的 [Ca(2+) ]i 有效地激活了 Mmp3 启动子荧光素酶报告基因，表明在转录水平上进行了调节。此外，还在源自神经干细胞的纯星形胶质细胞培养物中证实了 Ca(2+) /CN/NFAT 依赖性 Mmp3 表达，表明诱导的 Mmp3 表达发生在星形胶质细胞中，而不是小胶质细胞中。在脑损伤的刺戳伤模型中，在 NFATc3 阳性瘢痕形成星形胶质细胞中检测到 MMP3 表达。由于 [Ca(2+) ]i 增加是大多数脑损伤的早期事件，这些数据支持 Ca(2+) /CN/NFAT 诱导的星形胶质细胞 MMP3 表达在早期神经炎症反应中的重要作用。了解参与这种调节的分子途径可能为促进受损大脑的恢复提供新的治疗靶标和方法。
