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Journal of the American Society of... Oct 2019Serum oxalate levels suddenly increase with certain dietary exposures or ethylene glycol poisoning and are a well known cause of AKI. Established contributors to oxalate... (Comparative Study)
Comparative Study
BACKGROUND
Serum oxalate levels suddenly increase with certain dietary exposures or ethylene glycol poisoning and are a well known cause of AKI. Established contributors to oxalate crystal-induced renal necroinflammation include the NACHT, LRR and PYD domains-containing protein-3 (NLRP3) inflammasome and mixed lineage kinase domain-like (MLKL) protein-dependent tubule necroptosis. These studies examined the role of a novel form of necrosis triggered by altered mitochondrial function.
METHODS
To better understand the molecular pathophysiology of oxalate-induced AIK, we conducted studies in mouse and human kidney cells and studies in mice, including wild-type mice and knockout mice deficient in peptidylprolyl isomerase F (Ppif) or deficient in both Ppif and Mlkl.
RESULTS
Crystals of calcium oxalate, monosodium urate, or calcium pyrophosphate dihydrate, as well as silica microparticles, triggered cell necrosis involving PPIF-dependent mitochondrial permeability transition. This process involves crystal phagocytosis, lysosomal cathepsin leakage, and increased release of reactive oxygen species. Mice with acute oxalosis displayed calcium oxalate crystals inside distal tubular epithelial cells associated with mitochondrial changes characteristic of mitochondrial permeability transition. Mice lacking Ppif or Mlkl or given an inhibitor of mitochondrial permeability transition displayed attenuated oxalate-induced AKI. Dual genetic deletion of and or pharmaceutical inhibition of necroptosis was partially redundant, implying interlinked roles of these two pathways of regulated necrosis in acute oxalosis. Similarly, inhibition of mitochondrial permeability transition suppressed crystal-induced cell death in primary human tubular epithelial cells. PPIF and phosphorylated MLKL localized to injured tubules in diagnostic human kidney biopsies of oxalosis-related AKI.
CONCLUSIONS
Mitochondrial permeability transition-related regulated necrosis and necroptosis both contribute to oxalate-induced AKI, identifying PPIF as a potential molecular target for renoprotective intervention.
Topics: Acute Kidney Injury; Animals; Cells, Cultured; Humans; Male; Mice; Mitochondrial Transmembrane Permeability-Driven Necrosis; Necroptosis; Oxalates
PubMed: 31296606
DOI: 10.1681/ASN.2018121218 -
PloS One 2023Oxalate oxidase is an enzyme that degrades oxalate and is used in commercial urinary assays to measure oxalate levels. The objective of this study was to establish an...
Oxalate oxidase is an enzyme that degrades oxalate and is used in commercial urinary assays to measure oxalate levels. The objective of this study was to establish an enhanced expression system for secretion and purification of oxalate oxidase using Pichia pastoris. A codon optimized synthetic oxalate oxidase gene derived from Hordeum vulgare (barley) was generated and cloned into the pPICZα expression vector downstream of the N-terminal alpha factor secretion signal peptide sequence and used for expression in P. pastoris X-33 strain. A novel chimeric signal peptide consisting of the pre-OST1 sequence fused to pro-αpp8 containing several amino acid substitutions was also generated to enhance secretion. Active enzyme was purified to greater than 90% purity using Q-Sepharose anion exchange chromatography. The purified oxalate oxidase enzyme had an estimated Km value of 256μM, and activity was determined to be 10U/mg. We have developed an enhanced oxalate oxidase expression system and method for purification.
Topics: Hordeum; Pichia; Protein Sorting Signals; Oxalates; Recombinant Proteins
PubMed: 37167324
DOI: 10.1371/journal.pone.0285556 -
Journal of the... 2023Nephrolithiasis is a common disease that seriously affects the health and life quality of patients. Despite the reported effect of hyperoside (Hyp) against...
BACKGROUND
Nephrolithiasis is a common disease that seriously affects the health and life quality of patients. Despite the reported effect of hyperoside (Hyp) against nephrolithiasis, the specific mechanism has not been clarified. Therefore, this study is aimed at investigating the effect and potential mechanism of Hyp on renal injury and calcium oxalate (CaOx) crystal deposition.
METHODS
Rat and cell models of renal calculi were constructed by ethylene glycol (EG) and CaOx induction, respectively. The renal histopathological damage, CaOx crystal deposition, and renal function damage of rats were assessed by HE staining, Pizzolato staining, and biochemical detection of blood and urine parameters. MTT and crystal-cell adhesion assays were utilized to determine the activity of HK-2 cells and crystal adhesion ability, biochemical detection and enzyme-linked immunosorbent assay (ELISA) to measure the levels of oxidative stress-related substances and inflammatory factors, and western blot to test the expression levels of proteins related to the AMPK/Nrf2 signaling pathway.
RESULTS
Briefly speaking, Hyp could improve the renal histopathological injury and impaired renal function, reduce the deposition of CaOx crystals in the renal tissue of rats with renal calculi, and decrease the adhesion of crystals to CaOx-treated HK-2 cells. Besides, Hyp also significantly inhibited oxidative stress response. Furthermore, Hyp was associated with the downregulation of malondialdehyde, lactate dehydrogenase, and reactive oxygen species and upregulation of superoxide dismutase activity. Additionally, Hyp treatment also suppressed inflammatory response and had a correlation with declined levels of interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor. Further exploration of mechanism manifested that Hyp might play a protective role through promoting AMPK phosphorylation and nuclear translation of Nrf2 to activate the AMPK/Nrf2 signaling pathway.
CONCLUSION
Hyp can improve renal pathological and functional damage, decrease CaOx crystal deposition, and inhibit oxidative stress and inflammatory response. Such effects may be achieved by activating the AMPK/Nrf2 signaling pathway.
Topics: Rats; Animals; Calcium Oxalate; NF-E2-Related Factor 2; AMP-Activated Protein Kinases; Oxalates; Kidney; Kidney Calculi; Signal Transduction; Oxidative Stress; Calcinosis
PubMed: 36942317
DOI: 10.1155/2023/5445548 -
Nature Communications Apr 2023An oxalate-degrading bacterium in the gut microbiota absorbs food-derived oxalate to use this as a carbon and energy source, thereby reducing the risk of kidney stone...
An oxalate-degrading bacterium in the gut microbiota absorbs food-derived oxalate to use this as a carbon and energy source, thereby reducing the risk of kidney stone formation in host animals. The bacterial oxalate transporter OxlT selectively uptakes oxalate from the gut to bacterial cells with a strict discrimination from other nutrient carboxylates. Here, we present crystal structures of oxalate-bound and ligand-free OxlT in two distinct conformations, occluded and outward-facing states. The ligand-binding pocket contains basic residues that form salt bridges with oxalate while preventing the conformational switch to the occluded state without an acidic substrate. The occluded pocket can accommodate oxalate but not larger dicarboxylates, such as metabolic intermediates. The permeation pathways from the pocket are completely blocked by extensive interdomain interactions, which can be opened solely by a flip of a single side chain neighbouring the substrate. This study shows the structural basis underlying metabolic interactions enabling favourable symbiosis.
Topics: Animals; Oxalates; Gastrointestinal Microbiome; Bacterial Proteins; Membrane Transport Proteins; Biological Transport; Bacteria
PubMed: 37012268
DOI: 10.1038/s41467-023-36883-5 -
Biochimica Et Biophysica Acta.... Sep 2022Meals rich in oxalate are associated with calcium oxalate (CaOx) kidney stone disease. Hydroxy-L-proline (HLP) is an oxalate precursor found in milk and...
Meals rich in oxalate are associated with calcium oxalate (CaOx) kidney stone disease. Hydroxy-L-proline (HLP) is an oxalate precursor found in milk and collagen-containing foods. HLP has been shown to induce CaOx crystal formation in rodents. The purpose of this study was to evaluate the effect of HLP induced oxalate levels on inflammation and renal leukocytes during crystal formation. Male Sprague-Dawley rats (6-8 weeks old) were fed a control diet containing no oxalate for 3 days before being randomized to continue the control diet or 5% HLP for up to 28 days. Blood, 24 h urine, and kidneys were collected on Days 0, 7, 14, or 28. Urinary oxalate levels, crystal deposition, and renal macrophage markers were evaluated using ion chromatography-mass spectrometry, immunohistochemistry, and qRT-PCR. Renal leukocytes were assessed using flow cytometry and RNA-sequencing. HLP feeding increased urinary oxalate levels and renal crystal formation in animals within 7 days. HLP also increased renal macrophage populations on Days 14 and 28. Transcriptome analysis revealed that renal macrophages from animals fed HLP for 7 days were involved in inflammatory response and disease, stress response to LPS, oxidative stress, and immune cell trafficking. Renal macrophages isolated on Day 14 were involved in cell-mediated immunological pathways, ion homeostasis, and inflammatory response. Collectively, these findings suggest that HLP-mediated oxalate levels induce markers of inflammation, leukocyte populations, and reprograms signaling pathways in macrophages in a time-dependent manner. Additional studies investigating the significance of oxalate on renal macrophages could aid in our understanding of kidney stone formation.
Topics: Animals; Calcium Oxalate; Hydroxyproline; Inflammation; Kidney Calculi; Macrophages; Male; Nephrolithiasis; Oxalates; Rats; Rats, Sprague-Dawley
PubMed: 35562038
DOI: 10.1016/j.bbadis.2022.166442 -
Urolithiasis Feb 2017The intestine exerts a considerable influence over urinary oxalate in two ways, through the absorption of dietary oxalate and by serving as an adaptive extra-renal... (Review)
Review
The intestine exerts a considerable influence over urinary oxalate in two ways, through the absorption of dietary oxalate and by serving as an adaptive extra-renal pathway for elimination of this waste metabolite. Knowledge of the mechanisms responsible for oxalate absorption and secretion by the intestine therefore have significant implications for understanding the etiology of hyperoxaluria, as well as offering potential targets for future treatment strategies for calcium oxalate kidney stone disease. In this review, we present the recent developments and advances in this area over the past 10 years, and put to the test some of the new ideas that have emerged during this time, using human and mouse models. A key focus for our discussion are the membrane-bound anion exchangers, belonging to the SLC26 gene family, some of which have been shown to participate in transcellular oxalate absorption and secretion. This has offered the opportunity to not only examine the roles of these specific transporters, revealing their importance to oxalate homeostasis, but to also probe the relative contributions made by the active transcellular and passive paracellular components of oxalate transport across the intestine. We also discuss some of the various physiological stimuli and signaling pathways which have been suggested to participate in the adaptation and regulation of intestinal oxalate transport. Finally, we offer an update on research into Oxalobacter formigenes, alongside recent investigations of other oxalate-degrading gut bacteria, in both laboratory animals and humans.
Topics: Animals; Biological Transport; Humans; Hyperoxaluria; Intestinal Absorption; Intestinal Mucosa; Kidney Calculi; Oxalates
PubMed: 27913853
DOI: 10.1007/s00240-016-0952-z -
Waste Management (New York, N.Y.) Sep 2022Hydrothermal carbonization (HTC) is a treatment technique with great potential for sanitizing digested sewage sludge (SS) and converting it into valuable products. In...
Hydrothermal carbonization (HTC) is a treatment technique with great potential for sanitizing digested sewage sludge (SS) and converting it into valuable products. In particular, phosphorus (P) recovery from hydrothermally carbonized SS has attracted special attention in recent years. This work aims to examine the leaching efficiency of P and the consequent release of metals and heavy metals from SS hydrochars (at 180, 215 and 250 °C) using organic acids (oxalate and citrate) over a range of pH values (0-4) and extraction times (5 min-24 h). Both organic acids triggered P extraction efficiencies exceeding 75 % at the lowest pH, but only oxalate reached a nearly complete P release from hydrochars at pH > 0 and for all carbonization temperatures. Low HTC temperature (180 °C) and short extraction time (5 min) were the optimal conditions treatment for P recovery when reacted in oxalate solutions of maximal pH buffering capacity (pH = 1.4). However, oxalate leaching also transferred metals/heavy metals into the P-leachate, with the exception of Ca being retained in the solid residue from HTC as Ca-oxalate precipitate. Different characterization methods confirmed the presence of this precipitate, and provided information about the surface and morphological changes of the SS hydrochars following acid treatment. The results suggest that HTC not only a promising technique to sanitize and reduce the volume of SS, but also an efficient means for P recovery using oxalic acid, thus contributing to the circular economy of P.
Topics: Carbon; Metals, Heavy; Organic Chemicals; Oxalates; Phosphorus; Sewage; Temperature
PubMed: 35926282
DOI: 10.1016/j.wasman.2022.07.023 -
Microbiological Research May 2024Formation of calcium oxalate (CaOx) crystal, the most common composition in kidney stones, occurs following supersaturation of calcium and oxalate ions in the urine. In... (Review)
Review
Formation of calcium oxalate (CaOx) crystal, the most common composition in kidney stones, occurs following supersaturation of calcium and oxalate ions in the urine. In addition to endogenous source, another main source of calcium and oxalate ions is dietary intake. In the intestinal lumen, calcium can bind with oxalate to form precipitates to be eliminated with feces. High intake of oxalate-rich foods, inappropriate amount of daily calcium intake, defective intestinal transporters for oxalate secretion and absorption, and gastrointestinal (GI) malabsorption (i.e., from gastric bypass surgery) can enhance intestinal oxalate absorption, thereby increasing urinary oxalate level and risk of kidney stone disease (KSD). The GI microbiome rich with oxalate-degrading bacteria can reduce intestinal oxalate absorption and urinary oxalate level. In addition to the oxalate-degrading ability, the GI microbiome also affects expression of oxalate transporters and net intestinal oxalate transport, cholesterol level, and short-chain fatty acids (SCFAs) production, leading to lower KSD risk. Recent evidence also shows beneficial effects of urinary microbiome in KSD prevention. This review summarizes the current knowledge on the aforementioned aspects. Potential benefits of the GI and urinary microbiomes as probiotics for KSD prevention are emphasized. Finally, challenges and future perspectives of probiotic treatment in KSD are discussed.
Topics: Humans; Oxalates; Calcium; Kidney Calculi; Calcium Oxalate; Microbiota; Ions
PubMed: 38422861
DOI: 10.1016/j.micres.2024.127663 -
Frontiers in Immunology 2021Oxidative stress, a well-known cause of stress-induced premature senescence (SIPS), is increased in patients with calcium oxalate (CaOx) kidney stones (KS). Oxalate and...
Premature Senescence and Telomere Shortening Induced by Oxidative Stress From Oxalate, Calcium Oxalate Monohydrate, and Urine From Patients With Calcium Oxalate Nephrolithiasis.
Oxidative stress, a well-known cause of stress-induced premature senescence (SIPS), is increased in patients with calcium oxalate (CaOx) kidney stones (KS). Oxalate and calcium oxalate monohydrate (COM) induce oxidative stress in renal tubular cells, but to our knowledge, their effect on SIPS has not yet been examined. Here, we examined whether oxalate, COM, or urine from patients with CaOx KS could induce SIPS and telomere shortening in human kidney (HK)-2 cells, a proximal tubular renal cell line. Urine from age- and sex-matched individuals without stones was used as a control. In sublethal amounts, HO, oxalate, COM, and urine from those with KS evoked oxidative stress in HK-2 cells, indicated by increased protein carbonyl content and decreased total antioxidant capacity, but urine from those without stones did not. The proportion of senescent HK-2 cells, as indicated by SA-βgal staining, increased after treatment with HO, oxalate, COM, and urine from those with KS. Expression of p16 was higher in HK-2 cells treated with HO, oxalate, COM, and urine from those with KS than it was in cells treated with urine from those without stones and untreated controls. p16 was upregulated in the SA-βgal positive cells. Relative telomere length was shorter in HK-2 cells treated with HO, oxalate, COM, and urine from those with KS than that in cells treated with urine from those without stones and untreated controls. Transcript expression of shelterin components (TRF1, TRF2 and POT1) was decreased in HK-2 cells treated with HO, oxalate, COM, and urine from those with KS, in which case the expression was highest. Urine from those without KS did not significantly alter TRF1, TRF2, and POT1 mRNA expression in HK-2 cells relative to untreated controls. In conclusion, oxalate, COM, and urine from patients with CaOx KS induced SIPS and telomere shortening in renal tubular cells. SIPS induced by a lithogenic milieu may result from upregulation of p16 and downregulation of shelterin components, specifically POT1, and might contribute, at least in part, to the development of CaOx KS.
Topics: Aged; Aging, Premature; Calcium Oxalate; Cell Line; Cyclin-Dependent Kinase Inhibitor p16; DNA Damage; Female; Humans; Hydrogen Peroxide; Male; Middle Aged; Nephrolithiasis; Oxalates; Oxidative Stress; Telomere Shortening; Telomeric Repeat Binding Protein 1
PubMed: 34745087
DOI: 10.3389/fimmu.2021.696486 -
Cells Nov 2022Secretion of oxalic acid from roots is an important aluminum detoxification mechanism for many plants such as (rubber tree). However, the underlying molecular mechanism...
Secretion of oxalic acid from roots is an important aluminum detoxification mechanism for many plants such as (rubber tree). However, the underlying molecular mechanism and oxalate transporter genes in plants have not yet been reported. In this study, the oxalate transporter candidate genes and from the rubber tree were cloned and preliminarily identified. It was found that had a full length of 1163 bp with CDS size of 792 bp, encoding 263 amino acids, and had a full length of 1647 bp with a CDS region length of 840 bp, encoding 279 amino acid residues. HbOT1 and HbOT2 were both stable hydrophobic proteins with transmembrane structure and SNARE_assoc domains, possibly belonging to the SNARE_assoc subfamily proteins of the SNARE superfamily. qRT-PCR assays revealed that and were constitutively expressed in different tissues, with highly expressed in roots, stems, barks, and latex, while was highly expressed in latex. In addition, the expressions of and were up-regulated in response to aluminum stress, and they were inducible by metals, such as copper and manganese. Heterologous expression of and in the yeast mutant AD12345678 enhanced the tolerance to oxalic acid and high concentration aluminum stress, which was closely correlated with the secretion of oxalic acid. This study is the first report on oxalate transporter genes in plants, which provides a theoretical reference for the study on the molecular mechanism of oxalic acid secretion to relieve aluminum toxicity and on aluminum-tolerance genetic engineering breeding.
Topics: Hevea; Oxalates; Aluminum; Gene Expression Regulation, Plant; Plant Proteins; Membrane Transport Proteins
PubMed: 36497054
DOI: 10.3390/cells11233793