Noel Sanjeev, Martina Maria N, Bandapalle Samatha, Racusen Lorraine C, Potteti Haranatha R, Hamad Abdel R A, Reddy Sekhar P, Rabb Hamid
Division of Nephrology, Department of Medicine and.
Division of Immunopathology, Department of Pathology, Johns Hopkins University, Baltimore, Maryland; and.
J Am Soc Nephrol. 2015 Dec;26(12):2989-3000. doi: 10.1681/ASN.2014100978. Epub 2015 Aug 20.
T lymphocytes are established mediators of ischemia reperfusion (IR)-induced AKI, but traditional immune principles do not explain their mechanism of early action in the absence of alloantigen. Nrf2 is a transcription factor that is crucial for cytoprotective gene expression and is generally thought to have a key role in dampening IR-induced AKI through protective effects on epithelial cells. We proposed an alternative hypothesis that augmentation of Nrf2 in T cells is essential to mitigate oxidative stress during IR-induced AKI. We therefore generated mice with genetically amplified levels of Nrf2 specifically in T cells and examined the effect on antioxidant gene expression, T cell activation, cytokine production, and IR-induced AKI. T cell-specific augmentation of Nrf2 significantly increased baseline antioxidant gene expression. These mice had a high frequency of intrarenal CD25(+)Foxp3(+) regulatory T cells and decreased frequencies of CD11b(+)CD11c(+) and F4/80(+) cells. Intracellular levels of TNF-α, IFN-γ, and IL-17 were significantly lower in CD4(+) T cells with high Nrf2 expression. Mice with increased T cell expression of Nrf2 were significantly protected from functional and histologic consequences of AKI. Furthermore, adoptive transfer of high-Nrf2 T cells protected wild-type mice from IR injury and significantly improved their survival. These data demonstrate that T cell-specific activation of Nrf2 protects from IR-induced AKI, revealing a novel mechanism of tissue protection during acute injury responses.
T淋巴细胞是缺血再灌注(IR)诱导的急性肾损伤(AKI)的既定介质,但传统免疫原理无法解释它们在缺乏同种异体抗原时的早期作用机制。Nrf2是一种转录因子,对细胞保护基因表达至关重要,通常被认为在减轻IR诱导的AKI中通过对上皮细胞的保护作用发挥关键作用。我们提出了另一种假设,即T细胞中Nrf2的增强对于减轻IR诱导的AKI期间的氧化应激至关重要。因此,我们生成了在T细胞中Nrf2基因水平特异性扩增的小鼠,并研究了其对抗氧化基因表达、T细胞活化、细胞因子产生和IR诱导的AKI的影响。T细胞特异性增强Nrf2显著增加了基线抗氧化基因表达。这些小鼠肾内CD25(+)Foxp3(+)调节性T细胞频率较高,而CD11b(+)CD11c(+)和F4/80(+)细胞频率较低。Nrf2高表达的CD4(+) T细胞中TNF-α、IFN-γ和IL-17的细胞内水平显著降低。Nrf2在T细胞中表达增加的小鼠对AKI的功能和组织学后果具有显著的保护作用。此外,高Nrf2 T细胞的过继转移保护野生型小鼠免受IR损伤,并显著提高其存活率。这些数据表明,T细胞特异性激活Nrf2可保护免受IR诱导的AKI,揭示了急性损伤反应期间组织保护的新机制。