Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, USA.
Nephrol Dial Transplant. 2011 Jun;26(6):1778-85. doi: 10.1093/ndt/gfq692. Epub 2010 Nov 15.
Exposure of renal epithelial cells to oxalate (Ox) or calcium oxalate (CaOx) crystals leads to the production of reactive oxygen species and cell injury. We have hypothesized that Ox and CaOx crystals activate NADPH oxidase through upregulation of its various subunits.
Human renal epithelial-derived cell line, HK-2, was exposed to 100 μmol Ox or 66.7 μg/cm(2) CaOx monohydrate crystals for 6, 12, 24 or 48 h. After exposure, the cells and media were processed to determine activation of NADPH oxidase, production of superoxide and 8-isoprostane (8IP), and release of lactate dehydrogenase (LDH). RT-PCR was performed to determine mRNA expression of NADPH subunits p22(phox), p40(phox), p47(phox), p67(phox) and gp91(phox) as well as Rac-GTPase.
Exposure to Ox and CaOx crystals resulted in increase in LDH release, production of 8-IP, NADPH oxidase activity and production of superoxide. Exposure to CaOx crystals resulted in significantly higher NADPH oxidase activity, production of superoxide and LDH release than Ox exposure. Exposure to Ox and CaOx crystals altered the expression of various subunits of NADPH oxidase. More consistent were increases in the expression of membrane-bound p22(phox) and cytosolic p47(phox). Significant and strong correlations were seen between NADPH oxidase activity, the expression of p22(phox) and p47(phox), production of superoxide and release of LDH when cells were exposed to CaOx crystals. The expressions of neither p22(phox) nor p47(phox) were significantly correlated with increased NADPH oxidase activity after the Ox exposure.
As hypothesized, exposure to Ox or CaOx crystals leads to significant increases in the expression of p22(phox) and p47(phox), leading to activation of NADPH oxidase. Increased NADPH oxidase activity is associated with increased superoxide production and lipid peroxidation. Different pathways appear to be involved in the stimulation of renal epithelial cells by exposure to Ox and CaOx crystals.
草酸（Ox）或草酸钙（CaOx）晶体暴露于肾上皮细胞会导致活性氧物质的产生和细胞损伤。我们假设 Ox 和 CaOx 晶体通过上调其各种亚基来激活 NADPH 氧化酶。
将人肾上皮细胞系 HK-2 暴露于 100 μmol Ox 或 66.7 μg/cm(2)一水合 CaOx 晶体中 6、12、24 或 48 小时。暴露后，处理细胞和培养基以确定 NADPH 氧化酶的激活、超氧阴离子和 8-异前列腺素（8IP）的产生以及乳酸脱氢酶（LDH）的释放。进行 RT-PCR 以确定 NADPH 亚基 p22(phox)、p40(phox)、p47(phox)、p67(phox)和 gp91(phox)以及 Rac-GTPase 的 mRNA 表达。
暴露于 Ox 和 CaOx 晶体导致 LDH 释放、8-IP 产生、NADPH 氧化酶活性和超氧阴离子产生增加。暴露于 CaOx 晶体导致 NADPH 氧化酶活性、超氧阴离子产生和 LDH 释放显著高于 Ox 暴露。暴露于 Ox 和 CaOx 晶体改变了 NADPH 氧化酶的各种亚基的表达。更一致的是，膜结合的 p22(phox)和胞质 p47(phox)的表达增加。当细胞暴露于 CaOx 晶体时，NADPH 氧化酶活性、p22(phox)和 p47(phox)的表达、超氧阴离子的产生和 LDH 的释放之间存在显著且强的相关性。Ox 暴露后，p22(phox)和 p47(phox)的表达均与 NADPH 氧化酶活性的增加无显著相关性。
正如假设的那样，暴露于 Ox 或 CaOx 晶体导致 p22(phox)和 p47(phox)的表达显著增加，导致 NADPH 氧化酶激活。NADPH 氧化酶活性的增加与超氧阴离子产生和脂质过氧化增加有关。暴露于 Ox 和 CaOx 晶体刺激肾上皮细胞似乎涉及不同的途径。
