He Zhibin, Dursun Belda, Oh Dong-Jin, Lu Lawrence, Faubel Sarah, Edelstein Charles L
Division of Renal Diseases, University of Colorado Denver and the Health Sciences Center, Aurora, Colorado 80262, USA.
Am J Physiol Renal Physiol. 2009 Mar;296(3):F535-42. doi: 10.1152/ajprenal.90634.2008. Epub 2009 Jan 7.
We previously reported in ischemic acute kidney injury (AKI) in mice that caspase-1-mediated production of interleukin-18 (IL-18) is pathogenic and that macrophage depletion by liposome-encapsulated clodronate (LEC) is protective. Therefore, our aim was to determine whether macrophages are a source of IL-18 in ischemic AKI in mice. On immunofluorescence staining of the outer stripe of outer medulla, the number of macrophages double stained for CD11b and IL-18 was significantly increased in AKI and significantly decreased by LEC. Adoptive transfer of RAW 264.7 cells, a mouse macrophage line that constitutively expresses IL-18 mRNA, reversed the functional protection against AKI in both LEC-treated wild-type and caspase-1 -/- mice. To test whether IL-18 in macrophages is necessary to cause AKI, we adoptively transferred macrophages in which IL-18 was inhibited. Peritoneal macrophages isolated from wild-type mice, IL-18 binding protein transgenic (IL-18 BP Tg) mice, and IL-18 -/- mice were used. IL-18 BP Tg mice overexpress human IL-18 BP and exhibit decreased biological activity of IL-18. Adoptive transfer of peritoneal macrophages from wild-type as well as IL-18 BP Tg and IL-18 -/- mice reversed the functional protection against AKI in LEC-treated mice. In summary, adoptive transfer of RAW cells, that constitutively express IL-18, reverses the functional protection in macrophage-depleted wild-type and caspase-1 -/- mice with AKI. However, adoptive transfer of peritoneal macrophages in which IL-18 function was inhibited also reverses the functional protection in macrophage-depleted mice. In conclusion, IL-18 from adoptive transfer of macrophages is not sufficient to cause ischemic AKI.
我们之前报道，在小鼠缺血性急性肾损伤（AKI）中，半胱天冬酶-1介导的白细胞介素-18（IL-18）生成具有致病性，而脂质体包裹的氯膦酸盐（LEC）清除巨噬细胞具有保护作用。因此，我们的目的是确定巨噬细胞是否是小鼠缺血性AKI中IL-18的来源。在肾外髓质外层的免疫荧光染色中，AKI小鼠中CD11b和IL-18双染的巨噬细胞数量显著增加，而LEC可使其显著减少。RAW 264.7细胞是一种组成性表达IL-18 mRNA的小鼠巨噬细胞系，将其过继转移可逆转LEC处理的野生型和半胱天冬酶-1基因敲除（caspase-1 -/-）小鼠对AKI的功能保护作用。为了检测巨噬细胞中的IL-18是否是导致AKI所必需的，我们过继转移了IL-18被抑制的巨噬细胞。使用从野生型小鼠、IL-18结合蛋白转基因（IL-18 BP Tg）小鼠和IL-18基因敲除（IL-18 -/-）小鼠分离的腹膜巨噬细胞。IL-18 BP Tg小鼠过表达人IL-18 BP，且IL-18的生物活性降低。过继转移野生型以及IL-18 BP Tg和IL-18 -/-小鼠的腹膜巨噬细胞可逆转LEC处理小鼠对AKI的功能保护作用。总之，过继转移组成性表达IL-18的RAW细胞可逆转巨噬细胞耗竭的野生型和caspase-1 -/- AKI小鼠的功能保护作用。然而，过继转移IL-18功能被抑制的腹膜巨噬细胞也可逆转巨噬细胞耗竭小鼠的功能保护作用。总之，过继转移巨噬细胞产生的IL-18不足以导致缺血性AKI。
