P0532CD8+CD103+ INDUCED REGULATORY T CELLS BUT NOT NATURE REGULATORY T CELLS AMELIORATE IR-INDUCED KIDNEY INJURY

Abstract

Abstract Background and Aims Acute kidney injury (AKI) is one of the most common complications in clinical practice, but current approaches offer no cures for AKI. Inflammatory response is the key mechanism of ischemia reperfusion (IR)-induce AKI, known as hypoxia/reoxygenation injury. T lmphocytes are crucial mediators of IR-induced AKI. It is reported that regulatory T cell (Treg) has potential ability to ameliorate IR-induced AKI. Tregs consist of nature Treg (nTreg) and induced Treg (iTreg), which are well established to blunt immune responses. We confirmed that CD8+CD103+iTreg remain steadily and barely transfer into Th17, which produce proinflammatory response, under inflammatory response. It is studied that nTreg tends to transfer into Th17 under inflammatory condition, which clarifies the instability of nTreg. Thus, the instability of nTreg under inflammatory response hints us that nTreg are not suitable for recovery from IR-induced AKI. Accordingly, we studied the role of CD8+CD103+iTreg in repair after IR-induced kidney. Method In vitro study, we test the expression of CD103, Foxp3 and IL-17a in CD8+CD103+iTreg under 1% O2 concentration. In vivo study, SPF C57BL/6J male mice (8-10 weeks old, body weight 20-25g) were divided into four groups, sham-operated control group, AKI group, iTreg treatment group and nTreg treatment group, with 6 mice in each group. On the day of surgery, we anesthetize the mice (pen-tobarbital sodium, 50 mg/kg body weight). Mice in the AKI group were reperfused after 25 minutes of bilateral renal artery ischemia. We injected CD8+CD103+iTreg (2 × 106/mouse) or nTreg (2 × 106/mouse) intraperitoneally after 24 hours of modeling to the treatment group and euthanized the mice on the third day of anesthesia. Results We discovered that the expression of CD103 is stable in CD8+iTreg in vitro under 1% O2 concentration (Figure 1, 2). In addition, their inhibiting abilities of T cells proliferation in vitro remain steadily (Figure not shown). However, CD8+CD103+iTreg seldom transfer into Th17, but remain Foxp3 under hypoxic condition (Figure 2). Adoptively transferring CD8+CD103+iTregs, a new subpopulation of CD8+iTreg we have identified, to AKI mice, we found that these cells can ameliorate the development of AKI by mitigating the level of serum creatine, alleviating acute tubular necrosis (ATN) and decreasing the mortality of AKI. Conclusion Therefore, we confirmed that CD8+CD103+iTreg is stable under inflammatory(hypoxic) environment. Thus, CD8+CD103+iTreg targeting may be a novel therapeutic approach to enhance recovery from IR-induced AKI.