Feng Xu1, Man Wu2, Xuehong Lu2, Hong Zhang3, Lin Shi3, Yue Xi3, Huifen Zhou3, Junhong Wang3, Lining Miao2, Da-Wei Gong3, Wenpeng Cui4. 1. Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China; Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine at Baltimore, United States. 2. Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China. 3. Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine at Baltimore, United States. 4. Department of Nephrology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China. Electronic address: wenpengcui@163.com.
Abstract
INTRODUCTION: Renal ischemia/reperfusion injury (IRI) is the most common cause of acute kidney injury (AKI), and patients with AKI have a high rate of mortality. Apelin is a therapeutic candidate for treatment of IRI and Elabela (ELA) is a recently discovered hormone that also activates the apelin receptor (APJ). We examined the use of ELA as a preventive treatment for IRI using in vitro and in vivo models. METHODS: Male mice were subjected to renal IRI, with or without administration of a stabilized form of ELA (Fc-ELA-21) for 4 days. Renal tubular lesions were measured using H&E staining, reactive oxygen species (ROS) were measured using a dihydroethidium stain assay, and renal cell apoptosis was measured using the TUNEL assay and flow cytometry. Immortalized human proximal tubular epithelial (HK-2) cells were pretreated with or without LY294002 and/or ELA-32, maintained at normoxic or hypoxic conditions, and then returned to normal culture conditions to mimic IRI. Cell apoptosis was determined using the TUNEL assay and cell proliferation was determined using the MTT assay. The levels of Akt, p-Akt, ERK1/2, p- ERK1/2, Bcl-2, Bax, caspase-3 and cleaved caspase-3 were measured using western blotting. RESULTS: Fc-ELA-21 administration reduced renal tissue damage, ROS production, and apoptosis in mice that had renal IRI. ELA-32 reduced HK-2 cell apoptosis and restored the proliferation of cells subjected to IRI. Akt phosphorylation had a role in the anti-apoptotic effect of ELA. CONCLUSION: This study of in vitro and in vivo models of IRI indicated that the preventive and anti-apoptotic effects of ELA were mediated via the PI3K/Akt signaling pathway.
INTRODUCTION: Renal ischemia/reperfusion injury (IRI) is the most common cause of acute kidney injury (AKI), and patients with AKI have a high rate of mortality. Apelin is a therapeutic candidate for treatment of IRI and Elabela (ELA) is a recently discovered hormone that also activates the apelin receptor (APJ). We examined the use of ELA as a preventive treatment for IRI using in vitro and in vivo models. METHODS: Male mice were subjected to renal IRI, with or without administration of a stabilized form of ELA (Fc-ELA-21) for 4 days. Renal tubular lesions were measured using H&E staining, reactive oxygen species (ROS) were measured using a dihydroethidium stain assay, and renal cell apoptosis was measured using the TUNEL assay and flow cytometry. Immortalized human proximal tubular epithelial (HK-2) cells were pretreated with or without LY294002 and/or ELA-32, maintained at normoxic or hypoxic conditions, and then returned to normal culture conditions to mimic IRI. Cell apoptosis was determined using the TUNEL assay and cell proliferation was determined using the MTT assay. The levels of Akt, p-Akt, ERK1/2, p- ERK1/2, Bcl-2, Bax, caspase-3 and cleaved caspase-3 were measured using western blotting. RESULTS: Fc-ELA-21 administration reduced renal tissue damage, ROS production, and apoptosis in mice that had renal IRI. ELA-32 reduced HK-2 cell apoptosis and restored the proliferation of cells subjected to IRI. Akt phosphorylation had a role in the anti-apoptotic effect of ELA. CONCLUSION: This study of in vitro and in vivo models of IRI indicated that the preventive and anti-apoptotic effects of ELA were mediated via the PI3K/Akt signaling pathway.