metallothionein and Acute-Kidney-Injury

Crucial points of in situ hybridization methods were pointed out for study on the kidney diseases at molecular level. As examples of in situ hybridization study on kidney, we introduced two cases: 1) expression of the hepatocyte growth factor gene during renal regeneration after unilateral nephrectomy, and 2) induction of the metallothionein gene expression by ischemic acute renal failure. We proposed an idea to establish a probe bank for the in situ hybridization study.

Topics: Acute Kidney Injury; Animals; Cloning, Molecular; DNA; Gene Expression; Hepatocyte Growth Factor; Humans; In Situ Hybridization; Kidney Diseases; Liver Regeneration; Metallothionein

Polymyxin B (PMB) is one of the most effective drugs for the treatment of multi-resistant and pan-resistant gram-negative infections. However, it can induce acute kidney injury (AKI), the mechanism of which has not yet been fully elucidated. In this study, RNA sequencing and in vitro and in vivo experiments demonstrated that PMB induced AKI by promoting ferroptosis. Moreover, the metallothionein-1 (MT-1) level was significantly increased in the AKI group and clinical cases revealed that iron and MT-1 levels in urine were significantly higher in patients with AKI than in those without AKI. To explore the mechanism of PMB induced ferroptosis, we silenced p53 in human kidney-2 (HK2) cells according to RNA sequencing, which showed that p53 was obviously enhanced in the PMB treated group. While PMB significantly enhanced Fe

Topics: Acute Kidney Injury; Ferroptosis; Glutathione; Humans; Iron; Metallothionein; Polymyxin B; Tumor Suppressor Protein p53

As a main clinical feature of obstructive sleep apnea (OSA), intermittent hypoxia (IH) induces oxidative stress, leading to damage to a variety of organs, including kidney. Metallothionein (MT) is a potent antioxidant that protects kidney against oxidative damage. Our previous studies demonstrated that MT prevented IH-induced cardiomyopathy in mice. However, the role of MT in protecting against IH-induced renal injury is unknown. Therefore, MT knockout (MT KO) mice and wild type (WT) control mice (129S) were culled for exposure to intermittent air as control or IH for a time course of 3 days, 1 week, 3 weeks and 8 weeks. MT KO mice developed higher urinary albumin to creatinine ratio (UACR) after exposure to IH for 8 weeks. Compared with either MT KO control or WT IH mice, MT deletion significantly aggravated IH-induced renal oxidative damage and inflammation at all four time points, along with significant acceleration of renal fibrosis after exposure to IH for 3 weeks and 8 weeks. Antioxidants including MT, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase 1 (HO1) and NAD (P) H dehydrogenase [quinone] 1 (NQO1) were increased in response to short-term IH (3 days, 1 week and 3 weeks) but decreased after long-term IH (8 weeks) in WT mice. Interestingly, Nrf2, HO1 and NQO1 were significantly attenuated under IH conditions in the absence of MT, which were in parallel with the inactivation of protein kinase B (Akt) and extracellular signal-regulated kinase (ERK). These findings demonstrated that MT played a key role in preventing IH-induced renal injury possibly via preserving Nrf2 signaling pathway.

Topics: Acute Kidney Injury; Albuminuria; Animals; Antioxidants; Fibrosis; Gene Deletion; Hypoxia; Kidney Function Tests; Lipid Peroxidation; Metallothionein; Mice; Mice, Knockout; Nephritis

Subcutaneous injection of sodium arsenite (NaAs, 12.5 mg/kg) into BALB/c [wild-type (WT)] mice causes acute renal dysfunction characterized by severe hemorrhages, acute tubular necrosis, and cast formation, with increases in serum blood urea nitrogen and creatinine levels. Concomitant enhancement in intrarenal interferon (IFN)-gamma expression prompted us to examine its roles in this pathology. IFN-gamma-deficient (IFN-gamma-/-) mice exhibited higher serum blood urea nitrogen and creatinine levels and exaggerated histopathological changes, compared with WT mice. Eventually, IFN-gamma-/- mice exhibited a high mortality (87.5%) within 24 hours after NaAs challenge, whereas most WT mice survived. The intrarenal arsenic concentration was significantly higher in IFN-gamma-/- mice later than 10 hours after NaAs treatment, with attenuated intrarenal expression of multidrug resistance-associated protein (MRP) 1, a main transporter for NaAs efflux, compared with WT mice. NF-E2-related factor (Nrf) 2 protein, a transcription factor crucial for MRP1 gene expression, was similarly increased in the kidneys of both strains of mice after NaAs treatment. In contrast, the absence of IFN-gamma augmented transforming growth factor-beta-Smad3 signal pathway and eventually enhanced the expression of activating transcription factor 3, which is presumed to repress Nrf2-mediated MRP1 gene expression. Thus, IFN-gamma can protect against NaAs-induced acute renal injury, probably by maintaining Nrf2-mediated intrarenal MRP1 gene expression.

Topics: Acute Kidney Injury; Animals; Antibodies; Arsenites; ATP Binding Cassette Transporter, Subfamily B, Member 1; Gene Expression Regulation; Interferon-gamma; Kidney Tubules; Male; Metallothionein; Mice; Mice, Inbred BALB C; Mice, Mutant Strains; Multidrug Resistance-Associated Proteins; NF-E2-Related Factor 2; RNA, Messenger; Signal Transduction; Sodium Compounds; Transforming Growth Factor beta; Up-Regulation

Metallothionein (MT) is induced by various types of oxidative stress. However, whether or not MT is induced in renal ischemia/reperfusion injury, in which oxidative stress is believed to play a major role, remains unknown. The present study investigated MT expression in the kidneys of rats with ischmic acute renal failure (IARF). Rats were subjected to 60 min of bilateral renal ischemia followed by reperfusion. Renal MT mRNA expression was then analyzed by Northern blotting. MT expression in ischemic kidney was also localized by in situ hybridization and immunohistochemistry. Renal MT mRNA expression, which was barely detectable in the sham-operated control kidney, increased significantly at 3 h afer reperfsion, continued to increase to a maximal level at 24 h that was maintained for 48 h. The level of MT mRNA expression returned to that of the control by day 4. A morphological study revealed that MT was expressed exclusively in the renal tubular epithelial cells, which are the targets of ischemia/reperfusion injury, and that MT predominated in the outer medulla in the IARF rat kidney at transcriptional and translational levels. These results suggest that MT induced in the IARF rat kidney plays an important role in protecting renal cells against oxidative stress induced by ischemia/reperfusion.

Topics: Acute Kidney Injury; Animals; Creatinine; In Situ Hybridization; Ischemia; Kidney; Male; Metallothionein; Rats; Rats, Sprague-Dawley; RNA, Messenger

Zinc may have an antioxidant effect mediated by induction of metallothionein. Based on the assumption that metallothionein can scavenge oxygen free radicals, we examined whether zinc administration prior to renal ischemia would improve renal dysfunction caused by ischemia-reperfusion injury in rats. Wistar rats weighing 265 g were treated with an intraperitoneal injection of 20 mg/kg zinc 24 h prior to the renal ischemia-reperfusion procedure, which was achieved by a 30-min clamping of the bilateral renal vessels and subsequent 90-min reperfusion. Thirty-minute renal clearance tests were performed before and after renal ischemia in zinc- (n = 11) and saline-treated (n = 8) rats. Thiobarbituric acid reactive substance, conjugated diene, and metallothionein levels in the renal tissues were also determined. Sham-operated rats (n = 5 in each treatment) served as control for the ischemia-reperfusion rats. Ischemia-reperfusion resulted in significantly lower glomerular filtration rate values and marked increases in tissue concentrations of thiobarbituric acid reactive substance and conjugated diene compared with sham-operation. Zinc administration improved the reduced glomerular filtration rate values seen after the ischemia-reperfusion procedure, but not to the extent of pre-ischemic levels. Zinc pretreatment significantly reduced the increased levels of thiobarbituric acid reactive substance and conjugated diene during ischemia-reperfusion and increased metallothionein levels compared with saline injection. These findings suggest that zinc has an antioxidant effect mediated through the induction of metallothionein, but appears only to have a minor protective effect on renal function induced by renal ischemia-reperfusion injury.

Topics: Acute Kidney Injury; Animals; Antioxidants; Disease Models, Animal; Glomerular Filtration Rate; Kidney; Lipid Peroxidation; Male; Metallothionein; Rats; Rats, Wistar; Reactive Oxygen Species; Renal Circulation; Reperfusion Injury; Thiobarbiturates; Treatment Outcome; Zinc

We examined the role of reactive oxygen metabolites and the protective effect of zinc-induced metallothionein (MT) synthesis on gentamicin nephrotoxicity both in vivo and in vitro. In vivo study we found that the MT content of renal cortex of the zinc preinjected rats was significantly increased, and proximal tubular necrosis and acute renal failure caused by injection of gentamicin were ameliorated. In suspended proximal tubules (PT), Na(+)-K(+)-ATPase activity and DNA synthesis were suppressed by the addition of gentamicin, but in zinc-pretreated rats' PT, these were not suppressed by the addition of gentamicin. Meanwhile MDA and hydroxyl radicals were significantly less in zinc-pretreated rats' PT compared to that in the control. Finally, we found that gentamicin enhanced superoxide anion and hydroxyl radical productin in renal cortical mitochondria. Superoxide anion could be suppressed by SOD and hydroxyl radical could be scavenged by DMSO, DFO and CAT. Our data confirm that hydroxyl radicals play a role in the pathogenesis of gentamicin nephrotoxicity, gentamicin can induce suppression of Na(+)-K(+)-ATPase activity and DNA synthesis in rats' proximal tubules leading to renal injury; this injury may be relevant to reactive oxygen metabolites generated by gentamicin. Renal cortical mitochondria is the source of reactive oxygen metabolites, which induces renal injury, and zinc-induced metallothionein synthesis could ameliorate gentamicin nephrotoxicity via scavenging reactive oxygen metabolites.

Topics: Acute Kidney Injury; Animals; DNA; Free Radicals; Gentamicins; Hydroxyl Radical; In Vitro Techniques; Kidney; Kidney Cortex; Kidney Tubular Necrosis, Acute; Kidney Tubules, Proximal; Male; Metallothionein; Rats; Rats, Wistar; Reactive Oxygen Species; Sodium-Potassium-Exchanging ATPase; Zinc

Wistar rats were used to study the protective effect of zinc-induced metallothionein (MT) synthesis on gentamicin nephrotoxicity. We found that s.c. pre-injection of ZnSO4 (Zn 10 mg/kg/day) for 5 days could ameliorate proximal tubular necrosis and acute renal failure caused by an 8-day s.c. injection of gentamicin (100 mg/kg/day), while preinjection of saline instead of zinc or zinc and gentamicin together could not. In the zinc-pretreated rats (n = 6), renal cortical metallothionein level was significantly higher than that of normal (n = 8, p less than 0.001) and the saline controls (n = 6, p less than 0.001). Since MT is a scavenger of hydroxyl radical, it is proposed that hydroxyl radical plays a role in the pathogenesis of gentamicin nephrotoxicity and that preinjection of zinc could ameliorate gentamicin nephrotoxicity via the induction of renal cortical MT synthesis.

Topics: Acute Kidney Injury; Animals; Free Radical Scavengers; Gentamicins; Hydroxides; Hydroxyl Radical; Kidney Cortex; Kidney Tubular Necrosis, Acute; Male; Malondialdehyde; Metallothionein; Rats; Rats, Inbred Strains; Sulfates; Superoxide Dismutase; Zinc; Zinc Sulfate

In order to investigate the effect of cadmium-metallothionein (Cd-MT) on renal reabsorption of collagen metabolites, urinary excretion of hydroxylysine (Hyl), glucosyl-galactosyl-Hyl (Glc-Gal-Hyl), galactosyl-Hyl (Gal-Hyl), and hydroxyproline (Hyp), which are unique collagen metabolites, was determined in rats. Administration of Cd-MT resulted in acute renal failure in the form of proteinuria, aminoaciduria and glycosuria. Protein content in urine was greatly increased 1 day after injection of Cd-MT and decreased from 5 days, while the maximum levels of excretion of amino acids and glucose were observed at 6 days post-injection. The urinary excretion of total Hyp and Hyl, including Glc-Gal-Hyl, Gal-Hyl and free Hyl, were significantly increased at 3, 6 and 8 days after injection of Cd-MT with the maximum level at 6 days. Moreover, the molar ratio of Glc-Gal-Hyl/Gal-Hyl of urine in the Cd-MT-treated group was almost the same as that in the controls. These results suggest that a portion of Hyp, Hyl and its glycosides is normally reabsorbed from the renal tubule in the controls, and Cd-MT exposure caused an increase in urinary excretions of Hyp and Hyl, including its glycosides, through a renal tubular defect in reabsorption of Hyl in the same manner as with common amino acids.

Topics: Acute Kidney Injury; Animals; Cadmium; Female; Hydroxylysine; Hydroxyproline; Metallothionein; Mice; Rats; Rats, Inbred Strains