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您现在的位置：首页>美国卫生研究院文献>American Journal of Physiology - Renal Physiology

期刊信息

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  • 刊频： Twice monthly, Jan. 2012-
  • NLM标题： Am J Physiol Renal Physiol
  • iso缩写： -
  • ISSN： -

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  • 1.

    【2hr】Effect of renal lipid accumulation on proximal tubule Na+/H+ exchange and ammonium secretion

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    机译 肾脂质堆积对近端小管Na + / H +交换和氨分泌的影响
    摘要：Patients with metabolic syndrome have increased risk of uric acid nephrolithiasis due to lower urinary pH and impaired ammonium excretion. The pathophysiology underlying these urinary changes is unknown. We used two animal models and a cell culture model to study whether the alteration in renal acidification is associated with renal fat infiltration (steatosis). Compared with pair-fed lean control rats, Zucker diabetic fatty rats have higher renal triglyceride content, decreased urinary ammonium and pH, and lower levels of brush border membrane Na+/H+ exchanger-3 (NHE3), a major mediator of ammonium excretion. High-fat feeding in Sprague-Dawley rats results in transient lowering of urinary ammonium and pH, with all parameters returning to normal when the animals resumed eating normal chow. This is consistent with an absence of diet-induced renal steatosis in these animals. To examine the direct effect of fat accumulation, we incubated opossum kidney (OKP) cells with a mixture of long-chain fatty acids and found accumulation of intracellular lipids with concomitant dose-dependent decrease in NHE3 activity, surface biotin-accessible NHE3 protein, and ammonium secretion. A lower dose of fatty acids that leads to intracellular lipid accumulation but does not change baseline NHE3 is sufficient to abolish the stimulation of NHE3 by insulin and to partially block the stimulation of NHE3 by glucocorticoid hormones; acid regulation of NHE3 in lipid-loaded OKP cells is not affected. These findings suggest that renal steatosis decreases ammonium secretion in the proximal tubule, in part by reducing NHE3 activity and by impairing the regulation of NHE3 by specific agonists.
  • 2.

    【2hr】Arachidonic acid inhibits basolateral K channels in the cortical collecting duct via cytochrome P-450 epoxygenase-dependent metabolic pathways

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    机译 花生四烯酸通过细胞色素P-450环氧合酶依赖的代谢途径抑制皮质集合管中的基底外侧K通道
    摘要：We used the patch-clamp technique to study the effect of arachidonic acid (AA) on basolateral 18-pS K channels in the principal cell of the cortical collecting duct (CCD) of the rat kidney. Application of AA inhibited the 18-pS K channels in a dose-dependent manner and 10 μM AA caused a maximal inhibition. The effect of AA on the 18-pS K channel was specific because application of 11,14,17-eicosatrienoic acid had no effect on channel activity. Also, the inhibitory effect of AA on the 18-pS K channels was abolished by blocking cytochrome P-450 (CYP) epoxygenase with N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide (MS-PPOH) but was not affected by inhibiting CYP ω-hydroxylase or cyclooxygenase. The notion that the inhibitory effect of AA was mediated by CYP epoxygenase-dependent metabolites was further supported by the observation that application of 100 nM 11,12-epoxyeicosatrienoic acid (EET) mimicked the effect of AA and inhibited the basolateral 18-pS K channels. In contrast, addition of either 5,6-, 8,9-, or 14,15-EET failed to inhibit the 18-pS K channels. Moreover, application of 11,12-EET was still able to inhibit the 18-pS K channels in the presence of MS-PPOH. This suggests that 11,12-EET is a mediator for the AA-induced inhibition of the 18-pS K channels. We conclude that AA inhibits basolateral 18-pS K channels by a CYP epoxygenase-dependent pathway and that 11,12-EET is a mediator for the effect of AA on basolateral K channels in the CCD.
  • 3.

    【2hr】Sensitization of pelvic afferent nerves in the in vitro rat urinary bladder-pelvic nerve preparation by purinergic agonists and cyclophosphamide pretreatment

    包量

    机译 嘌呤能激动剂和环磷酰胺预处理可敏化体外大鼠膀胱-盆腔神经制剂中的盆腔传入神经
    摘要：Effects of purinergic agonists (α,β-meATP and ATP) and cyclophosphamide-induced cystitis on bladder afferent nerve (BAN) activity were studied in an in vitro bladder-pelvic nerve preparation. Distension of the bladder induced spontaneous bladder contractions that were accompanied by multiunit afferent firing. Intravesical administration of 40 and 130 µM α,β-meATP increased afferent firing from 27 ± 3 to 53 ± 6 and 61 ± 2 spikes/s, respectively, but did not change the maximum amplitude of spontaneous bladder contractions. Electrical stimulation on the surface of the bladder elicited action potentials (AP) in BAN. α,β-meATP decreased the voltage threshold from 9.0 ± 1.2 to 3.5 ± 0.5 V (0.15-ms pulse duration) and increased the area of the APs (82% at 80-V stimulus intensity). These effects were blocked by TNP-ATP (30 µM). ATP (2 mM) applied in the bath produced similar changes in BAN activity. These effects were blocked by bath application of PPADS (30 µM). Neither TNP-ATP nor PPADS affected BAN activity induced by distension of the bladder. Cystitis induced by pretreatment of the rats with cyclophosphamide (100 mg/kg ip) increased afferent firing in response to isotonic bladder distension (10–40 cmH2O), decreased the threshold, and increased the area of evoked APs. The increase in afferent firing at 10 cmH2O intravesical pressure was reduced 52% by PPADS. These results indicate that purinergic agonists acting on P2X receptors and cystitis induced by cyclophosphamide can increase excitability of the BANs.
  • 4.

    【2hr】Increased renal renin content in mice lacking the Na+/H+ exchanger NHE2

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    机译 缺乏Na + / H +交换子NHE2的小鼠的肾素含量增加
    摘要：Macula densa (MD) cells express the Na+/H+ exchanger (NHE) isoform NHE2 at the apical membrane, which may play an important role in tubular salt sensing through the regulation of cell volume and intracellular pH. These studies aimed to determine whether NHE2 participates in the MD control of renin synthesis. Renal renin content and activity and elements of the MD signaling pathway were analyzed using wild-type (NHE2+/+) and NHE2 knockout (NHE2−/−) mice. Immunofluorescence studies indicated that NHE2−/− mice lack NHE3 at the MD apical membrane, so the other apical NHE isoform has not compensated for the lack of NHE2. Importantly, the number of renin-expressing cells in the afferent arteriole in NHE2−/− mice was increased ∼2.5-fold using renin immunohistochemistry. Western blotting confirmed ∼20% higher renal cortical renin content in NHE2−/− mice compared with wild type. No-salt diet for 1 wk significantly increased renin content and activity in NHE2+/+ mice, but the response was blunted in NHE2−/− mice. Renal tissue renin activity and plasma renin concentration were elevated three- and twofold, respectively, in NHE2−/− mice compared with wild type. NHE2−/− mice also exhibited a significantly increased renal cortical cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase (mPGES) expression, indicating MD-specific mechanisms responsible for the increased renin content. Significant and chronic activation of ERK1/2 was observed in MD cells of NHE2−/− kidneys. Removal of salt or addition of NHE inhibitors to cultured mouse MD-derived (MMDD1) cells caused a time-dependent activation of ERK1/2. In conclusion, the NHE2 isoform appears to be important in the MD feedback control of renin secretion, and the signaling pathway likely involves MD cell shrinkage and activation of ERK1/2, COX-2, and mPGES, all well-established elements of the MD-PGE2-renin release pathway.
  • 5.

    【2hr】Transcriptional Control of Terminal Nephron Differentiation

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    机译 终末肾元分化的转录控制。
    摘要：Terminal differentiation of epithelial cells into more specialized cell types is a critical step of organogenesis. Throughout the process of terminal differentiation, epithelial progenitors acquire or up-regulate expression of renal function genes and cease to proliferate, while expression of embryonic genes is repressed. This exquisite coordination of gene expression is accomplished by signaling networks and transcription factors which couple the external environment with the new functional demands of the cell. While there has been much progress in understanding the early steps involved in renal epithelial cell differentiation, a major gap remains in our knowledge of the factors that control the steps of terminal differentiation. A number of signaling molecules and transcription factors have been recently implicated in determining segmental nephron identity and functional differentiation. While some of these factors (the p53 gene family, HNF1β) promote the terminal epithelial differentiation fate, others (Notch, Brn-1, IRX, KLF4 and Foxi1) tend to regulate differentiation of specific nephron segments and individual cell types. This article summarizes current knowledge related to these transcription factors and discusses how diverse cellular signals are integrated to generate a transcriptional output during the process of terminal differentiation. Since these transcriptional processes are accompanied by profound changes in nuclear chromatin structure involving the genes responsible for creating and maintaining the differentiated cell phenotype, future studies should focus on identifying the nature of these epigenetic events and factors, how they are regulated temporally and spatially, and the chromatin environment they eventually reside in.
  • 6.

    【2hr】Heterogeneity of muscarinic receptor-mediated Ca2+ responses in cultured urothelial cells from rat

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    机译 毒蕈碱受体介导的大鼠尿路上皮细胞中Ca2 +响应的异质性
    摘要：Muscarinic receptors (mAChRs) have been identified in the urothelium, a tissue that may be involved in bladder sensory mechanisms. This study investigates the expression and function of mAChRs using cultured urothelial cells from the rat. RT-PCR established the expression of all five mAChR subtypes. Muscarinic agonists acetylcholine (ACh; 10 μM), muscarine (Musc; 20 μM), and oxotremorine methiodide (OxoM; 0.001–20 μM) elicited transient repeatable increases in the intracellular calcium concentration ([Ca2+]i) in ∼50% of cells. These effects were blocked by the mAChR antagonist atropine methyl nitrate (10 μM). The sources of [Ca2+]i changes included influx from external milieu in 63% of cells and influx from external milieu plus release from internal stores in 27% of cells. The use of specific agonists and antagonists (10 μM M1 agonist McN-A-343; 10 μM M2, M3 antagonists AF-DX 116, 4-DAMP) revealed that M1, M2, M3 subtypes were involved in [Ca2+]i changes. The PLC inhibitor U-73122 (10 μM) abolished OxoM-elicited Ca2+ responses in the presence of the M2 antagonist AF-DX 116, suggesting that M1, M3, or M5 mediates [Ca2+]i increases via PLC pathway. ACh (0.1 μM), Musc (10 μM), oxotremorine sesquifumarate (20 μM), and McN-A-343 (1 μM) acting on M1, M2, and M3 mAChR subtypes stimulated ATP release from cultured urothelial cells. In summary, cultured urothelial cells express functional M1, M2, and M3 mAChR subtypes whose activation results in ATP release, possibly through mechanisms involving [Ca2+]i changes.
  • 7.

    【2hr】Studies on localization and function of annexin A4a within urinary bladder epithelium using a mouse knockout model

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    机译 利用小鼠基因敲除模型研究膜联蛋白A4a在膀胱上皮细胞中的定位和功能
    摘要：Annexin A4 (anxA4) is a member of the Ca2+-dependent membrane-binding family of proteins implicated in the regulation of ion conductances, Ca2+ homeostasis, and membrane trafficking. We demonstrate, in mice, that annexins 1-6 are present in whole bladder and exhibit differential expression in the urothelium. An anxA4a-knockout (anxA4a-/-) mouse model shows no protein in the urothelium by immunofluorescence and immunoblotting. In wild-type bladders, anxA4a in umbrella cells showed uniform cytoplasmic staining and some association with the nuclear membrane. Application of a hydrostatic pressure to bladders mounted in Ussing chambers resulted in redistribution of anxA4a from cytoplasm to cellular boundaries in the basal and intermediate cells but not in superficial umbrella cells. We hypothesized that anxA4a might be important for barrier function or for stretch-activated membrane trafficking. To test these hypotheses, we conducted a series of functional and morphological analyses on bladders from control and anxA4a-/- animals. The transepithelial resistances, water permeabilities, and urea permeabilities of anxA4a-/- bladders were not different from controls, indicating that barrier function was intact. Membrane trafficking in response to hydrostatic pressure as measured by capacitance increases was also normal for anxA4a-/- bladders. Cystometrograms performed on live animals showed that voiding frequency and intrabladder pressures were also not different. There were no differences in bladder surface morphology or cellular architecture examined by scanning and transmission electron microscopy, respectively. We conclude that loss of anxA4 from the urothelium does not affect barrier function, membrane trafficking, or normal bladder-voiding behavior.
  • 8.

    【2hr】Expression and function of rat urothelial P2Y receptors

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    机译 大鼠尿路上皮P2Y受体的表达和功能
    摘要：The control and regulation of the lower urinary tract (LUT) is partly mediated by purinergic signaling. This study investigated the distribution and function of P2Y receptors in the rat urinary bladder. Application of P2Y agonists to rat urothelial cells evoked increases in intracellular calcium; the rank order of agonist potency (pEC50 ± S.E.M.) was ATP (5.10 ± 0.07)>UTP (4.91 ± 0.14)>UTPγS (4.61 ± 0.16) = ATPγS (4.70 ± 0.05) > 2MeSADP = NECA = ADP (<3.5). The rank order potency for these agonists indicates that urothelial cells functionally express P2Y2/P2Y4 receptors, with a relative lack of contribution from other P2Y or adenosine receptors. Real-time PCR, western blotting and immunocytochemistry, confirmed the expression of P2Y2, and to a lesser extent P2Y4 in the urothelium. Immunocytochemical studies revealed expression of P2Y2 staining in all layers of the urothelium, with relative absence of P2Y4. P2Y2 staining was also present in sub-urothelial nerve bundles and underlying detrusor smooth muscle. Addition of UTP and UTPγS was found to evoke ATP release from cultured rat urothelial cells. These findings indicate that cultured rat urothelial cells functionally express P2Y2/P2Y4 receptors. Activation of these receptors could have a role in autocrine and paracrine signaling throughout the urothelium. This could lead to the release of bioactive mediators such as additional ATP, nitric oxide and acetylcholine, which can modulate the micturition reflex by acting on sub-urothelial myofibroblasts and/or pelvic afferent fibers.
  • 9.

    【2hr】20-HETE-mediated cytotoxicity and apoptosis in ischemic kidney epithelial cells

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    机译 20-HETE介导的缺血性肾上皮细胞的细胞毒性和凋亡
    摘要：20-HETE, a metabolite of arachidonic acid, has been implicated as a mediator of free radical formation and tissue death following ischemia- reperfusion (IR) injury in the brain and heart. The present study examined the role of this pathway in a simulated IR renal injury model in vitro. Modified self-inactivating lentiviral vectors were generated to stably overexpress murine Cyp4a12 following transduction into LLC-PK1 cells (LLC-Cyp4a12). We compared the survival of control and transduced LLC-PK1 cells following 4 h of ATP depletion and 2 h of recovery in serum-free medium. ATP depletion-recovery of LLC-Cyp4a12 cells resulted in a significantly higher LDH release (P < 0.05) compared with LLC-enhanced green fluorescent protein (EGFP) cells. Treatment with the SOD mimetic MnTMPyP (100 µM) resulted in decreased cytotoxicity in LLC-Cyp4a12 cells. The selective 20-HETE inhibitor HET-0016 (10 µM) also inhibited cytotoxicity significantly (P < 0.05) in LLC-Cyp4a12 cells. Dihydroethidium fluorescence showed that superoxide levels were increased to the same degree in LLC-EGFP and LLC-Cyp4a12 cells after ATP depletion-recovery compared with control cells and that this increase was inhibited by MnTMPyP. There was a significant increase (P < 0.05) of caspase-3 cleavage, an effector protease of the apoptotic pathway, in the LLC-Cyp4a12 vs. LLC-EGFP cells (P < 0.05). This was abolished in the presence of HET-0016 (P < 0.05) or MnTMPyP (P < 0.01). These results demonstrate that 20-HETE overexpression can significantly exacerbate the cellular damage that is associated with renal IR injury and that the programmed cell death is mediated by activation of caspase-3 and is partially dependent on enhanced CYP4A generation of free radicals.
  • 10.

    【2hr】Partial nephrectomy as a model for uremic cardiomyopathy in the mouse

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    机译 肾部分切除术作为小鼠尿毒症心肌病的模型
    摘要：Because of the plethora of genetic manipulations available in the mouse, we performed a partial nephrectomy in the mouse and examined whether the phenotypical features of uremic cardiomyopathy described in humans and rats were also present in the murine model. A ⅚ nephrectomy was performed using a combination of electrocautory to decrease renal mass on the left kidney and right surgical nephrectomy. This procedure produced substantial and persistent hypertension as well as increases in circulating concentrations of marinobufagenin. Invasive physiological measurements of cardiac function demonstrated that the ⅚ nephrectomy resulted in impairment of both active and passive left ventricular relaxation at 4 wk whereas tissue Doppler imaging detected changes in diastolic function after 6 wk. Morphologically, hearts demonstrated enlargement and progressive fibrosis, and biochemical measurements demonstrated downregulation of the sarcoplasmic reticulum calcium ATPase as well as increases in collagen-1, fibronectin, and vimentin expression. Our results suggest that partial nephrectomy in the mouse establishes a model of uremic cardiomyopathy which shares phenotypical features with the rat model as well as patients with chronic renal failure.
  • 11.

    【2hr】Effect of thyroid hormone on the postnatal renal expression of NHE8

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    机译 甲状腺激素对产后肾脏NHE8表达的影响
    摘要：We previously demonstrated that there are developmental changes in proximal tubule Na+/H+ exchanger (NHE) activity. There is a maturational increase in postnatal brush-border membrane (BBM) vesicle NHE3 protein abundance and decrease in NHE8 protein abundance. The purpose of this study was to determine whether thyroid hormone plays a role in the rat renal maturational isoform switch from NHE8 to NHE3 and whether thyroid hormone regulates NHE8. Administration of thyroid hormone to neonatal rats, before the normal postnatal increase in serum thyroid hormone levels at 3 wk of age, resulted in a premature increase in NHE3/β-actin BBM protein abundance and mRNA abundance. Thyroid hormone also caused a premature decrease in BBM NHE8/β-actin protein abundance, whereas there was no change in mRNA expression (standardized to 28s). Rats made hypothyroid from birth were studied at 28 days, after the normal maturational increase in thyroid hormone. In these hypothyroid adult rats, the maturational increase in BBM NHE3 protein abundance and NHE3 mRNA expression was prevented. In contrast, the developmental decrease in BBM NHE8 protein abundance was prevented in hypothyroid adults, but mRNA expression was unchanged in hypothyroid rats. To determine whether the effect of thyroid hormone was due to a direct epithelial effect, we studied normal rat kidney cells in culture. We recently showed that this cell line expresses NHE8, but does not express NHE3. Thyroid hormone caused a decrease in surface expression of NHE8, determined by biotinylation, but total cellular abundance remained unchanged. NHE8 activity, measured as the sodium-dependent rate of intracellular pH recovery from an acid load, was less with thyroid treatment than control. In conclusion, thyroid hormone plays a potential role in the developmental isoform change from NHE8 to NHE3 and decreases NHE8 activity.
  • 12.

    【2hr】Free radical stress-mediated loss of Kcnj10 protein expression in stria vascularis contributes to deafness in Pendred syndrome mouse model

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    机译 在Pendred综合征小鼠模型中，自由基应激介导的血管纹中Kcnj10蛋白表达的丧失导致耳聋
    摘要：Pendred syndrome is due to loss-of-function mutations of Slc26a4, which codes for the HCO3− transporter pendrin. Loss of pendrin causes deafness via a loss of the K+ channel Kcnj10 in stria vascularis and consequent loss of the endocochlear potential. Pendrin and Kcnj10 are expressed in different cell types. Here, we report that free radical stress provides a link between the loss of Kcnj10 and the loss of pendrin. Studies were performed using native and cultured stria vascularis from Slc26a4+/− and Slc26a4−/− mice as well as Chinese hamster ovary (CHO)-K1 cells. Kcnj10, oxidized proteins, and proteins involved in iron metabolism were quantified by Western blotting. Nitrated proteins were quantified by ELISA. Total iron was measured by ferrozine spectrophotometry and gene expression was quantified by qRT-PCR. At postnatal day 10 (P10), stria vascularis from Slc26a4+/− and Slc26a4−/− mice expressed similar amounts of Kcnj10. Slc26a4−/− mice lost Kcnj10 expression during the next 5 days of development. In contrast, stria vascularis, obtained from P10 Slc26a4−/− mice and kept in culture for 5 days, maintained Kcnj10 expression. Stria vascularis from Slc26a4−/− mice was found to suffer from free radical stress evident by elevated amounts of oxidized and nitrated proteins and other changes in protein and gene expression. Free radical stress induced by 3-morpholinosydnonimine-N-ethylcarbamide was found to be sufficient to reduce Kcnj10 expression in CHO-K1 cells. These data demonstrate that free radical stress provides a link between loss of pendrin and loss of Kcnj10 in Slc26a4−/− mice and possibly in human patients suffering from Pendred syndrome.
  • 13.

    【2hr】Time course of neuroanatomical and functional recovery after bilateral pudendal nerve injury in female rats

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    机译 雌性大鼠双侧阴部神经损伤后神经解剖和功能恢复的时程
    摘要：The pudendal nerve innervates the external urethral sphincter (EUS) and is among the tissues injured during childbirth, which may lead to symptoms of stress urinary incontinence (SUI). To understand the mechanisms of injury and repair, urethral leak-point pressure (LPP) was measured 4 days, 2 wk, or 6 wk after bilateral pudendal nerve crush. Morphometric changes in the distal nerve and EUS were examined by light and electron microscopy. To determine whether recovery resulted from pudendal neuroregeneration, LPP was measured before and after pudendal nerve transection 2 wk after nerve crush. LPP was significantly decreased 4 days after pudendal nerve crush compared with sham-injured animals as well as 2 or 6 wk after nerve crush. LPP was not significantly different 2 or 6 wk after nerve crush compared with sham-injured animals, suggesting that urethral function had returned to normal. Four days after pudendal nerve crush, the EUS branch of the pudendal nerve distal to the injury site showed evidence of nerve degeneration and the EUS appeared disrupted. Two weeks after nerve crush, the distal nerve and EUS both showed evidence of both nerve degeneration and recovery. Two weeks after nerve crush, LPP was significantly decreased after nerve transection. Six weeks after nerve injury, evidence of neuroregeneration was observed in the pudendal nerve and the EUS. This study has demonstrated that functional recovery and neuroregeneration are significant 2 wk after nerve crush, although by anatomical assessment, recovery appears incomplete, suggesting that 2 wk represents an early time point of initial neuroregeneration.
  • 14.

    【2hr】17β-estradiol attenuates diabetic kidney disease via regulating extracellular matrix and transforming growth factor-beta protein expression and signaling

    包量

    机译 17β-雌二醇通过调节细胞外基质并转化生长因子-β蛋白表达和信号传导来减轻糖尿病肾病
    摘要：We have previously shown that supplementation with 17β-estradiol (E2) from the onset of diabetes attenuates the development of diabetic renal disease. The aim of this study was to examine if E2 can also attenuate the disease process once it has already developed. The study was performed in non-diabetic (ND) and streptozotocin (STZ)-induced diabetic (D) Sprague-Dawley rats. E2 supplementation began after 9 weeks of diabetes for further 8 weeks. Diabetes was associated with an increase in urine albumin excretion (UAE) (ND; 9.4±1.0; D, 56.2±8.9 mg/day; P<0.001), glomerulosclerosis (GSI; ND, 0.13±0.02; D, 1.38±0.09 AU; P<0.01), tubulointerstitial fibrosis (TIFI; ND, 0.17±0.04; D, 1.35±0.10 AU; P<0.01), renal cortical collagen type I (CI; ND, 1.02±0.05; D, 1.83±0.03 ROD; P<0.001), collagen type IV (CIV; ND, 0.97±0.05; D, 1.56±0.03 ROD, P<0.01), laminin (L; ND, 1.03±.0.03; D, 1.80±0.02 ROD; P<0.001), PAI-1 (ND, 0.34±0.08; D, 0.88±0.03 ROD; P<0.01), TIMP-1 (ND, 0.30±0.07; D, 0.93±0.14 ROD; P<0.01), TIMP-2 (ND, 0.40±0.09; D, 0.96±0.11 ROD; P<0.01), TGF-β (ND; 0.70±0.14; D, 1.63±0.08 ROD; P<0.001), TGF-βRI (ND, 0.69±0.23; D, 1.47±0.14 ROD; P<0.05), TGF-βRI (ND, 0.40±0.09; D, 1.07±0.10 ROD; P<0.001), Smad2/3 (ND, 0.68±0.08; D, 1.71±0.03 ROD; P<0.01), pSmad2/3 (ND, 0.28±0.07; D, 0.74±0.12 ROD, P<0.05) and Smad4 (ND, 0.82±.0.24; D, 1.77±0.03 ROD; P<0.05) protein expression and CD68-positive cells (ND, 5.0±0.8; D, 33.8±2.4 cells/mm2; P<0.001). Decreases in MMP-2 (ND, 1.35±0.06; D, 0.98±0.05 ROD; P<0.05) protein expression and activity (MMP-2 act; ND, 0.39±0.09; D, 0.22±0.01 ROD; P<0.05), Smad6 (ND, 0.85±0.10; D, 0.40±0.03 ROD; P<0.001) and Smad7 (ND, 1.41±0.06; D, 1.01±0.05 ROD; P<0.05) protein expression were also associated with D. E2 supplementation either completely or partially attenuated these changes. We conclude that E2 attenuates the progression of disease once it has already developed via regulating extracellular matrix, TGF-β and expression of its downstream regulatory proteins.
  • 15.

    【2hr】Organic anion transporter 3 (Oat3/Slc22a8) knockout mice exhibit altered clearance and distribution of penicillin G

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    机译 基因敲除小鼠有机阴离子转运蛋白3（Oat3 / Slc22a8）的清除率和分布发生改变的青霉素G
    摘要：The interaction of renal basolateral organic anion transporter 3 (Oat3) with commonly used pharmacotherapeutics (e.g., NSAIDs, β-lactams, and methotrexate) has been studied extensively in vitro. However, the in vivo role of Oat3 in drug disposition, in the context of other transporters, glomerular filtration, and metabolism, has not been established. Moreover, recent investigations have identified inactive human OAT3 polymorphisms. Therefore, this investigation was designed to elucidate the in vivo role of Oat3 in the disposition of penicillin G and prototypical substrates using an Oat3 knockout mouse model. Oat3 deletion resulted in a doubling of penicillin’s half-life (P < 0.05) and a reduced volume of distribution (P < 0.01), together yielding a plasma clearance that was one-half (P < 0.05, males) to one-third (P < 0.001, females) of that in wild-type mice. Inhibition of Oat3 abolished the differences in penicillin G elimination between genotypes. Hepatic accumulation of penicillin was 2.3 times higher in male knockouts (P < 0.05) and 3.7 times higher in female knockouts (P < 0.001). Female knockouts also exhibited impaired estrone-3-sulfate clearance. Oat3 deletion did not impact p-aminohippurate elimination, providing correlative evidence to studies in Oat1 knockout mice that suggest Oat1 governs tubular uptake of p-aminohippurate. Collectively, these findings are the first to indicate that functional Oat3 is necessary for proper elimination of xenobiotic and endogenous compounds in vivo. Thus Oat3 plays a distinct role in determining the efficacy and toxicity of drugs. Dysfunctional human OAT3 polymorphisms or instances of polypharmacy involving OAT3 substrates may result in altered systemic accumulation of β-lactams and other clinically relevant compounds.
  • 16.

    【2hr】Activation and involvement of p53 in cisplatin-induced nephrotoxicity

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    机译 p53的激活和参与顺铂诱导的肾毒性
    摘要：Cisplatin, a widely used chemotherapy drug, induces acute kidney injury, which limits its use and efficacy in cancer treatment. However, the molecular mechanism of cisplatin-induced nephrotoxicity is currently unclear. Using pharmacological and gene knockout models, we now demonstrate a pathological role for p53 in cisplatin nephrotoxicity. In C57BL/6 mice, cisplatin treatment induced p53 phosphorylation and protein accumulation, which was accompanied by the development of acute kidney injury. p53 was induced in both proximal and distal tubular cells and partially colocalized with apoptosis. Pifithrin-α, a pharmacological inhibitor of p53, suppressed p53 activation and ameliorated kidney injury during cisplatin treatment. Moreover, cisplatin-induced nephrotoxicity was abrogated in p53-deficient mice. Compared with wild-type animals, p53-deficient mice showed a better renal function, less tissue damage, and fewer apoptotic cells. In addition, cisplatin induced less apoptosis in proximal tubular cells isolated from p53-deficient mice than the cells from wild-type animals. Together these results suggest the involvement of p53 in cisplatin-induced renal cell apoptosis and nephrotoxicity.
  • 17.

    【2hr】Detection of early changes in renal function using 99mTc-MAG3 imaging in a murine model of ischemia-reperfusion injury

    包量

    机译 在小鼠缺血再灌注损伤模型中使用99mTc-MAG3成像检测肾脏功能的早期变化
    摘要：Accurate determination of renal function in mice is a major impediment to the use of murine models in acute kidney injury. The purpose of this study was to determine whether early changes in renal function could be detected using dynamic gamma camera imaging in a mouse model of ischemia-reperfusion (I/R) injury. C57BL/6 mice (n = 5/group) underwent a right nephrectomy, followed by either 30 min of I/R injury or sham surgery of the remaining kidney. Dynamic renal studies (21 min, 10 s/frame) were conducted before surgery (baseline) and at 5, 24, and 48 h by injection of 99mTc-mercaptoacetyltriglycine (MAG3; ~1.0 mCi/mouse) via the tail vein. The percentage of injected dose (%ID) in the kidney was calculated for each 10-s interval after MAG3 injection, using standard region of interest analyses. A defect in renal function in I/R-treated mice was detected as early as 5 h after surgery compared with sham-treated mice, identified by the increased %ID (at peak) in the I/R-treated kidneys at 100 s (P < 0.01) that remained significantly higher than sham-treated mice for the duration of the scan until 600 s (P < 0.05). At 48 h, the renal scan demonstrated functional renal recovery of the I/R mice and was comparable to sham-treated mice. Our study shows that using dynamic imaging, renal dysfunction can be detected and quantified reliably as early as 5 h after I/R insult, allowing for evaluation of early treatment interventions.
  • 18.

    【2hr】Role of gap junctions in spontaneous activity of the rat bladder

    包量

    机译 间隙连接在大鼠膀胱自发活动中的作用
    摘要：Increased gap junction expression in lamina propria myofibroblasts and urothelial cells may be involved in detrusor overactivity, leading to incontinence. Immunohistochemistry was used to compare connexin (Cx) 26, 43, and 45 expression in the bladders of neonatal, adult, and spinal cord-transected rats, while optical imaging was used to map the spread of spontaneous activity and the effects of gap junction blockade. Female adult Sprague-Dawley rats were deeply anesthetized, a laminectomy was performed, and the spinal cord was transected (T8/T9). After 14 days, their bladders and those of age-matched adults (4 mo old) and neonates (7-21 day old) were excised and studied immunohistochemically using frozen sections or optically using whole bladders stained with voltage- and Ca2+-sensitive dyes. The expression of Cx26 was localized to the urothelium, Cx43 to the lamina propria myofibro-blasts, and Cx45 to the detrusor smooth muscle. While the expression of Cx45 was comparable in all bladders, the expression of Cx43 and Cx26 was increased in neonate and transected animals. In the bladders of adults, spontaneous activity was initiated at multiple sites, resulting in a lack of coordination. Alternatively, in neonate and transected animals spontaneous activity was initiated at a focal site near the dome and spread in a coordinated fashion throughout the bladder. Gap junction blockade (18β-glycyrrhetinic acid, 1 μM) abolished this coordinated activity but had no effect on the uncoordinated activity in adult bladders. These data suggest that coordinated spontaneous activity requires gap junction upregulation in urothelial cells and lamina propria myofibroblasts.
  • 19.

    【2hr】Characterization of Na+/H+ exchanger NHE8 in cultured renal epithelial cells

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    机译 肾上皮细胞中Na + / H +交换子NHE8的表征
    摘要：NHE8 is expressed in the apical membrane of the proximal tubule and is predicted to be a Na+/H+ exchanger on the basis of its primary amino acid sequence. Functional characterization of native NHE8 in mammalian cells has not been possible to date. We screened a number of polarized renal cell lines for the plasma membrane Na+/H+ exchangers (NHE1, 2, 3, 4, and 8) and found only NHE1 and NHE8 transcripts in NRK cells by RT-PCR. NHE8 protein is expressed in the apical membrane of NRK cells as demonstrated by immunoblots, confocal fluorescent immunocytochemistry, and immunoelectron microscopy. NHE1, on the other hand, is expressed primarily in the basolateral membrane. Bilateral perfusion of NRK cells grown on permeable supports shows Na+/H+ exchange activity on both the apical and basolateral membranes. NHE8-specific small interfering RNA knocks down NHE8 protein expression but does not affect NHE1 protein levels. Knockdown of NHE8 protein is accompanied by a commensurate reduction in apical NHE activity, without altered basolateral NHE activity. Conversely, transfection of NHE1-specific small interfering RNA knocks down NHE1 protein expression without affecting NHE8 protein levels and reduces basolateral NHE activity without affecting apical NHE activity. NHE8 is the only apical membrane Na+/H+ exchanger in NRK cells. NHE8 activity is Na+ dependent, displaying a cooperative sigmoidal relationship, and is highly sensitive to 5-(N-ethyl-n-isopropyl)-amiloride (EIPA). NRK cells provide a useful system where NHE8 can be studied in its native environment.
  • 20.

    【2hr】Novel sandwich ELISA for human angiotensinogen

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    机译 用于人血管紧张素原的新型夹心ELISA
    摘要：We recently reported that urinary excretion rates of angiotensinogen (UAGT) provide a specific index of intrarenal renin-angiotensin (ANG) system (RAS) status in ANG II-dependent hypertensive rats. When this is shown to be applicable to human subjects, a diagnostic test to identify those hypertensive patients most likely to respond to an RAS blockade could provide useful information to allow a mechanistic rationale for selection of an optimized approach to treatment of hypertensive patients. However, simple and accurate methods to measure human angiotensinogen (hAGT) are unavailable. For future studies of human subjects, we developed antibodies and a sensitive and specific quantification system for hAGT using a sandwich ELISA. We raised two antibodies against hAGT: a mouse monoclonal antibody and a rabbit polyclonal antibody. The standard curve of this ELISA exhibited a high linearity (0.31–20 ng/ml). The correlation coefficient was >0.99. Plasma angiotensinogen concentrations of healthy volunteers ranged from 28 to 71 μg/ml (n = 10). The ratio of UAGT to urinary creatinine concentration ranged from 5.0 to 30 μg/g (n = 7). Intra- and interassay coefficients of variation ranged from 4.4 to 5.5% and from 4.3 to 7.0%, respectively. This ELISA system had no cross-reactivity with major proteins in proteinuric urine samples, such as human albumin, immunoglobulin, or transferrin. Moreover, the cross-reactivity of the system with angiotensin peptides was also negligible. This hAGT ELISA will be a useful tool to investigate the relationship of UAGT and reactivity to antihypertensive drugs in hypertensive patients.
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