Protective Effects of Traditional Polyherbs on Cisplatin-Induced Acute Kidney Injury Cell Model by Inhibiting Oxidative Stress and MAPK Signaling Pathway.

Acute kidney injury (AKI) is a disease caused by sudden renal dysfunction, which is an important risk factor for chronic renal failure. However, there is no effective treatment for renal impairment. Although some traditional polyherbs are commercially available for renal diseases, their effectiveness has not been reported. Therefore, we examined the nephroprotective effects of polyherbs and their relevant mechanisms in a cisplatin-induced cell injury model. Rat NRK-52E and human HK-2 subjected to cisplatin-induced AKI were treated with four polyherbs, Injinhotang (IJ), Ucha-Shinki-Hwan (US), Yukmijihwang-tang (YJ), and UrofenTM (Uro) similar with Yondansagan-tang, for three days. All polyherbs showed strong free radical scavenging activities, and the treatments prevented cisplatin-induced cell death in both models, especially at 1.2 mg/mL. The protective effects involved antioxidant effects by reducing reactive oxygen species and increasing the activities of superoxide dismutase and catalase. The polyherbs also reduced the number of annexin V-positive apoptotic cells and the expression of cleaved caspase-3, along with inhibited expression of mitogen-activated protein kinase-related proteins. These findings provide evidence for promoting the development of herbal formulas as an alternative therapy for treating AKI.

Distinct roles of an ionic interaction holding an alpha-helix with catalytic Asp and a beta-strand with catalytic His in a hyperthermophilic esterase EstE1 and a mesophilic esterase rPPE.

An ionic interaction that holds an α-helix and a ß-strand on which catalytic Asp and His residues are located, respectively, is conserved in a hyperthermophilic esterase EstE1 (optimum temperature 70 °C) and a mesophilic esterase rPPE (optimum temperature 50 °C). We investigated the role of an ionic interaction between E258 and R275 in EstE1 and that between E263 and R280 in rPPE in active-site stability of serine esterases adapted to different temperatures. Ala substitutions caused a 5-10 °C decrease in the optimum temperature of both EstE1 and rPPE mutants. Surprisingly, disruption of the ionic interaction caused larger effects on the conformational flexibility of EstE1 mutants despite their rigid structures, whereas the disruption had fewer effects on the thermal stability of EstE1 mutants at 60-70 °C, as the structure of EstE1 was adapted to high temperatures. In contrast, mesophilic rPPE mutants showed dramatic decreases in thermal stability at 40-50 °C, but less changes in conformational flexibility because of their inherently flexible structures. The results of this study suggest that the ionic interaction between the α-helix with catalytic Asp and the ß-strand with catalytic His plays an important role in the active-site conformation of EstE1 and rPPE, with larger effects on the conformational flexibility of hyperthermophilic EstE1 and the thermal stability of mesophilic rPPE.

Protective Effects of Traditional Herbal Formulas on Cisplatin-Induced Nephrotoxicity in Renal Epithelial Cells via Antioxidant and Antiapoptotic Properties.

Acute kidney injury (AKI) is characterized by a rapid loss of renal function. Drug-induced AKI accounts for up to 60% of all cases, resulting in a severe threat particularly to hospitalized patients, but there are no effective treatments. Four polyherbal formulas, Bojungikki-tang (BJ), Palmijihwang-tang (PJ), Oryeong-san (OR), and Wiryeong-tang (WR), have long been used for treatments of symptoms of kidney disease in traditional Korean medicine. Even though they are commercially available, evidences supporting the efficacy on AKI are still lacking. Therefore, the effectiveness of polyherbs on AKI and the underlying mechanisms were examined. Renal cell damage was induced by cisplatin at 20 µM and 16 µM in proximal tubular epithelial cell lines of rat NRK-52E and human HK-2, respectively. The cells were treated with the polyherbal formals for 3 days, and the cell viability, antioxidant activities, and apoptosis were examined. In addition, the proliferative effects were assessed under serum-free conditions. The results were compared with those of the vehicle-treated cells as a control. Three polyherbs BJ, PJ, and WR but not OR showed strong free radical scavenging activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The treatments of BJ, PJ, OR, and WR significantly increased the cell viabilities under cisplatin-induced nephrotoxicity. Consistent with the results of the DPPH assay, superoxide dismutase and catalase activities were increased in the cisplatin-induced cell model treated with BJ, PJ, and WR but not with OR. However, annexin-V-positive cells and cleaved caspase 3 expression were significantly reduced in the cell model treated with all of the polyherbs. Cell proliferation was observed in treatment with all of the polyherbs, which was particularly evident in the OR-treated cells. This provides effective complementary evidences to promote the development of traditional herbal formulas to treat AKI.