Renal ischemia-reperfusion injury (IRI) is a major contributor to acute kidney injury (AKI), leading to substantial morbidity and mortality. Spexin (SPX), a 14-amino acid endogenous peptide involved in metabolic regulation and immune modulation, has not yet been studied in the context of chronic treatment and renal IRI. This study evaluated the effects of exogenous SPX on renal function, histopathological changes, and molecular pathways in both IRI-induced injured and healthy kidneys. Twenty-eight male BALB/c mice were divided into four groups: control, SPX, IRI, and SPX+IRI. IRI was induced by 30 minutes of bilateral renal ischemia followed by 6 hours of reperfusion. Renal injury markers, histopathological changes, inflammatory mediators, apoptotic markers, and fibrosis-related proteins were analyzed. SPX significantly exacerbated IRI-induced kidney injury by activating the Wnt/β-catenin signaling pathway and promoting the upregulation of pro-inflammatory, pro-apoptotic, and pro-fibrotic mediators. It is noteworthy that SPX exerted more severe deleterious nephrotoxic effects in the healthy kidney compared to those observed in the IRI-induced injured kidney. These findings indicate that chronic treatment with SPX administration may have intrinsic pro-inflammatory, pro-apoptotic and fibrotic properties, raising concerns about its therapeutic potential. Further research is needed to clarify its physiological role and therapeutic implications in kidney diseases.
Animals ; Reperfusion Injury/chemically induced* ; Male ; Mice, Inbred BALB C ; Mice ; Acute Kidney Injury/metabolism* ; Kidney/blood supply* ; Peptide Hormones/adverse effects* ; Apoptosis/drug effects* ; Wnt Signaling Pathway/drug effects* ; Disease Models, Animal

Peroxisome proliferator activated receptor-α (PPAR-α) is significantly expressed in various tissues such as the liver, kidney, myocardium, and skeletal muscle, which plays a central role in the development of various diseases by regulating key physiological processes such as energy homeostasis, redox balance, inflammatory response, and ferroptosis. As an important metabolic and excretory organ of the body, renal dysfunction can lead to water and electrolyte imbalance, toxin accumulation, and multiple system complications. The causes of kidney injury are complex and diverse, including acute injury factors (such as ischemia/reperfusion, nephrotoxic drugs, septic shock, and immune glomerulopathy), as well as chronic progressive causes [such as metabolic disease-related nephropathy, hypertensive nephropathy (HN)], and risk factors such as alcohol abuse, obesity, and aging. This review briefly describes the structure, function, and activity regulation mechanism of PPAR-α, systematically elucidates the molecular regulatory network of PPAR-α in the pathological process of kidney injury including acute kidney injury (AKI) such as renal ischemia/reperfusion injury (IRI), drug-induced AKI, sepsis-associated acute kidney injury (SA-AKI), glomerulonephritis, chronic kidney disease (CKD) such as diabetic nephropathy (DN), HN, and other kidney injury, and summarizes the mechanisms related to PPAR-α regulation of kidney injury, including regulation of metabolism, antioxidation, anti-inflammation, anti-fibrosis, and anti-ferroptosis. This review also evaluates PPAR-α's medical value as a novel therapeutic target, and aims to provide theoretical basis for the development of kidney protection strategies based on PPAR-α targeted intervention.
Humans ; PPAR alpha/metabolism* ; Acute Kidney Injury/therapy* ; Animals ; Kidney/metabolism*

OBJECTIVE: To investigate the effects of liriodendrin on the intestinal flora and the ferroptosis signaling pathway in renal tissue of rats with sepsis-induced acute kidney injury (AKI). METHODS: Thirty male Sprague-Dawley (SD) rats were randomly divided into sham operation group (Sham group), sepsis model induced by cecal ligation and puncture group (CLP group), and liriodendrin intervention group (CLP+LIR group), with 10 rats in each group. The CLP+LIR group was given 0.2 mL of 100 mg/kg liriodendrin by gavage 2 hours before modeling; Sham group and CLP group were given the same volume of normal saline by gavage. The samples were collected after anesthesia 24 hours after modeling. The pathological changes of renal tissue were observed by hematoxylin-eosin (HE) staining. The levels of inflammatory factors such as tumor necrosis factor-α (TNF-α), interleukins (IL-1β, IL-6) were detected by enzyme linked immunosorbent assay (ELISA). The levels of renal function indicators such as creatinine (Cr), and urea nitrogen (UREA) in peripheral blood, and the content of malondialdehyde (MDA) and Fe²⁺ in renal tissue were detected. Western blotting was used to detect the expressions of nuclear factor E2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4) and heme oxygenase-1 (HO-1) in renal tissues. The changes of intestinal flora were detected by 16S rDNA high-throughput sequencing. RESULTS: Compared with the Sham group, the CLP group showed significantly enlarged glomeruli, noticeable renal interstitial edema, disorganized kidney tissue, and significantly increased pathological scores. The contents of TNF-α, IL-1β, IL-6, Cr, and UREA in peripheral blood and the levels of MDA and Fe²⁺ in renal tissue were significantly increased. The protein expressions of Nrf2, GPX4, and HO-1 in renal tissue were significantly down-regulated. The species richness of intestinal flora decreased significantly, and the relative abundances of pathogenic bacteria such as Morganella, Citrobacter, Proteus, Klebsiella, Shigella, Aggregatibacter, and Enterococcus increased significantly, while the relative abundances of beneficial bacteria such as Butyricimonas, Veillonella, Prevotella, Lactobacillus, Bifidobacterium, and Ruminococcus decreased significantly. Compared with the CLP group, CLP+LIR group could significantly reduce the pathological damage of renal tissue, the pathological score significantly decreased (1.80±0.84 vs. 4.20±1.30, P < 0.05), and improve the composition of intestinal flora, reduce the relative abundances of pathogenic bacteria such as Proteus, Klebsiella, Shigella, Aggregatibacter, and Enterococcus, and significantly increase the relative abundances of Lactobacillus, Bifidobacterium, and Ruminococcus, significantly reduce the contents of TNF-α, IL-1β, IL-6, Cr, and UREA in peripheral blood and the levels of MDA and Fe²⁺ in renal tissue [blood TNF-α (ng/L): 191.31±7.23 vs. 254.90±47.89, blood IL-1β (ng/L): 11.15±4.04 vs. 23.06±1.67, blood IL-6 (ng/L): 163.20±17.83 vs. 267.69±20.92, blood Cr (μmol/L): 24.14±4.25 vs. 41.17±5.43, blood UREA (mmol/L): 4.59±0.90 vs. 8.01±1.07, renal MDA (μmol/g): 9.67±0.46 vs. 16.05±0.88, renal Fe²⁺ (mg/g): 0.71±0.07 vs. 0.93±0.04, all P < 0.05], and increase the protein expressions of Nrf2, GPX4, and HO-1 (Nrf2/GAPDH: 1.21±0.01 vs. 0.39±0.01, GPX4/GAPDH: 0.74±0.04 vs. 0.48±0.04, HO-1/GAPDH: 0.91±0.01 vs. 0.41±0.02, all P < 0.05). CONCLUSIONS Liriodendrin has an obvious protective effect on sepsis-induced AKI. The mechanism may involve regulating the intestinal flora, increasing the activation of the Nrf2/HO-1/GPX4 signaling pathway in renal tissue, and reducing ferroptosis.
Animals ; Acute Kidney Injury/microbiology* ; Rats, Sprague-Dawley ; Sepsis/complications* ; Male ; Ferroptosis/drug effects* ; Gastrointestinal Microbiome/drug effects* ; Rats ; Signal Transduction ; Kidney/metabolism* ; Tumor Necrosis Factor-alpha/metabolism*

Five previously undescribed diterpenoids, named succipenoids D‒H (1‒5), along with four undescribed lignans, named succignans A‒D (6‒9), were isolated from the dichloromethane extract of Chinese medicinal succinum. Compounds 1‒5 were characterized as nor-abietane diterpenoids, while compounds 6‒9 were identified as lignans polymerized from two groups of phenylpropanoid units. The structures of these novel compounds, including their absolute configurations, were determined through spectroscopic and computational methods. Biological assessments of renal fibrosis demonstrated that compounds 6 and 7 effectively reduce the expression of proteins associated with renal fibrosis, including α-smooth muscle actin (α-SMA), collagen I, and fibronectin in transforming growth factor-β1 (TGF-β1) induced normal rat kidney proximal tubular epithelial cells (NRK-52e).
Animals ; Rats ; Lignans/isolation & purification* ; Diterpenes/isolation & purification* ; Fibrosis/drug therapy* ; Drugs, Chinese Herbal/pharmacology* ; Molecular Structure ; Cell Line ; Kidney Diseases/pathology* ; Transforming Growth Factor beta1/genetics* ; Kidney/metabolism* ; Actins/genetics* ; Fibronectins/genetics* ; Collagen Type I/genetics* ; Epithelial Cells/metabolism*

OBJECTIVE: To explore the protective effects and underlying mechanisms of H ₂S against lipid peroxidation-mediated carbonyl stress in the uranium-treated NRK-52E cells. METHODS: Cell viability was evaluated using CCK-8 assay. Apoptosis was measured using flow cytometry. Reagent kits were used to detect carbonyl stress markers malondialdehyde, 4-hydroxynonenal, thiobarbituric acid reactive substances, and protein carbonylation. Aldehyde-protein adduct formation and alcohol dehydrogenase, aldehyde dehydrogenase 2, aldo-keto reductase, nuclear factor E2-related factor 2 (Nrf2), and cystathionine β-synthase (CBS) expression were determined using western blotting or real-time PCR. Sulforaphane (SFP) was used to activate Nrf2. RNA interference was used to inhibit CBS expression. RESULTS: GYY4137 (an H ₂S donor) pretreatment significantly reversed the uranium-induced increase in carbonyl stress markers and aldehyde-protein adducts. GYY4137 effectively restored the uranium-decreased Nrf2 expression, nuclear translocation, and ratio of nuclear to cytoplasmic Nrf2, accompanied by a reversal of the uranium-decreased expression of CBS and aldehyde-metabolizing enzymes. The application of CBS siRNA efficiently abrogated the SFP-enhanced effects on the expression of CBS, Nrf2 activation, nuclear translocation, and ratio of nuclear to cytoplasmic Nrf2 and concomitantly reversed the SFP-enhanced effects of the uranium-induced mRNA expression of aldehyde-metabolizing enzymes. Simultaneously, CBS siRNA reversed the SFP-mediated alleviation of the uranium-induced increase in reactive aldehyde levels, apoptosis rates, and uranium-induced cell viability. CONCLUSION H ₂S induces Nrf2 activation and nuclear translocation, which modulates the expression of aldehyde-metabolizing enzymes and the CBS/H ₂S axis. Simultaneously, the Nrf2-controlled CBS/H ₂S axis may at least partially promote Nrf2 activation and nuclear translocation. These events form a cycle-regulating mode through which H ₂S attenuates the carbonyl stress-mediated NRK-52E cytotoxicity triggered by uranium.
NF-E2-Related Factor 2/genetics* ; Animals ; Hydrogen Sulfide/pharmacology* ; Rats ; Signal Transduction/drug effects* ; Lipid Peroxidation/drug effects* ; Cell Line ; Uranium/toxicity* ; Antioxidant Response Elements ; Kidney/metabolism* ; Oxidative Stress/drug effects* ; Cell Survival/drug effects* ; Apoptosis/drug effects*

RNA methylation is a key process in the epigenetic regulation of post-transcriptional gene expression.5-Methylcytosine(m⁵C)is a type of RNA methylation,commonly existing in eukaryotic mRNA and non-coding RNAs.It mainly regulates transfer RNA stability,ribosomal RNA assembly,and mRNA translation,stability,and translation.RNA methylation is dynamically reversible and regulated by methyltransferase,demethylase,and methylation recognition protein.It has been confirmed that aberrant m⁵C RNA methylation is involved in the pathogenesis of non-neoplastic kidney diseases.This article summarizes the current progress of m⁵C RNA methylation associated with non-neoplastic acute and chronic kidney diseases,aiming to provide potential targets for the diagnosis and treatment of such diseases.
Humans ; Methylation ; 5-Methylcytosine/metabolism* ; Kidney Diseases/metabolism* ; Epigenesis, Genetic ; RNA Methylation

Kidney stones are a urinary system disease with a high incidence,among which calcium oxalate stones are the most common.Metabolic disorders such as hypertension,diabetes,obesity,hyperlipidemia,and hyperuricemia can cause changes in oxalate,uric acid,and pH and calcium ion concentrations in the urine through multiple pathways including inducing oxidative stress and inflammatory responses by generating reactive oxygen species,ultimately affecting the formation of calcium oxalate stones.This article reviews the possible pathways and mechanisms by which metabolic diseases influence the formation of calcium oxalate stones,providing new ideas for the clinical prevention and treatment of calcium oxalate stones.
Humans ; Calcium Oxalate/metabolism* ; Kidney Calculi/etiology* ; Metabolic Diseases/complications*

OBJECTIVE: To observe the clinical efficacy of warming acupuncture combined with western medication for oligoasthenoteratozoospermia of kidney-yang insufficiency and its effects on the levels of interleukin (IL)-6 and IL-10 in seminal plasma. METHODS: A total of 60 patients with oligoasthenoteratozoospermia of kidney-yang insufficiency were randomly divided into a combination group and a medication group, with 30 cases in each group. The medication group was treated with levocarnitine oral solution orally, 10 mL once, 3 times a day. On the basis of the treatment in the medication group, warming acupuncture was applied at Baihui (GV20), Guanyuan (CV4) and Mingmen (GV4) in the combination group, once every other day, 3 times a week. Both groups were treated for 12 weeks. Before and after treatment, the TCM syndrome score was observed, the semen routine indexes (the sperm concentration, progressive [PR] sperm motility, PR + non-progressive [NP] sperm motility and sperm malformation rate), the serum sex hormones indexes (follicle-stimulating hormone [FSH], luteinizing hormone [LH], testosterone [T] and estradiol [E₂]), as well as the IL-6 and IL-10 levels in seminal plasma were detected, and the clinical efficacy was evaluated after treatment in the two groups. RESULTS: After treatment, except for the hyposexuality score in the medication group, the each item scores and total scores of TCM syndrome were decreased compared with those before treatment (P<0.01, P<0.05), the sperm malformation rates, serum FSH and LH levels, IL-6 levels in the seminal plasma were decreased compared with those before treatment (P<0.01, P<0.05), the PR sperm motility, PR + NP sperm motility, serum T levels, IL-10 levels in the seminal plasma were increased compared with those before treatment (P<0.01, P<0.05) in the two groups; the sperm concentration was increased compared with that before treatment in the combination group (P<0.01). After treatment, compared with the medication group, except for the hyposexuality and frequent nocturia scores, the each item scores and total score of TCM syndrome were lower (P<0.01, P<0.05); the sperm concentration, PR sperm motility and PR + NP sperm motility, serum T level, IL-10 level in the seminal plasma were higher (P<0.01, P<0.05); sperm malformation rate, serum FSH and LH levels, IL-6 level in the seminal plasma were lower (P<0.01, P<0.05) in the combination group. The total effective rate was 83.8% (25/30) in the combination group, which was superior to 60.0% (18/30) in the medication group (P<0.05). CONCLUSION Warming acupuncture combined with western medication can effectively treat oligoasthenoteratozoospermia of kidney-yang insufficiency, regulate the levels of sex hormones, and its mechanism may be related to the down-regulation of IL-6 level and the up-regulation of IL-10 level in seminal plasma.
Humans ; Male ; Interleukin-10/genetics* ; Interleukin-6/genetics* ; Adult ; Semen/metabolism* ; Acupuncture Therapy ; Oligospermia/drug therapy* ; Yang Deficiency/physiopathology* ; Kidney/physiopathology* ; Young Adult ; Asthenozoospermia/drug therapy* ; Combined Modality Therapy ; Treatment Outcome

Acute kidney injury (AKI) is a common clinically critical syndrome in hospitalized patients with high morbidity and mortality. At present, the mechanism of AKI has not been fully elucidated, and no therapeutic drugs exist. As known, glycolytic product lactate is a key metabolite in physiological and pathological processes. The kidney is an important gluconeogenic organ, where lactate is the primary substrate of renal gluconeogenesis in physiological conditions. During AKI, altered glycolysis and gluconeogenesis in kidneys significantly disturb the lactate metabolic balance, which exert impacts on the severity and prognosis of AKI. Additionally, lactate-derived posttranslational modification, namely lactylation, is novel to AKI as it could regulate gene transcription of metabolic enzymes involved in glycolysis or Warburg effect. Protein lactylation widely exists in human tissues and may severely affect non-histone functions. Moreover, the strategies of intervening lactate metabolic pathways are expected to bring a new dawn for the treatment of AKI. This review focused on renal lactate metabolism, especially in proximal renal tubules after AKI, and updated recent advances of lactylation modification, which may help to explore potential therapeutic targets against AKI.
Humans ; Acute Kidney Injury/metabolism* ; Lactic Acid/metabolism* ; Animals ; Glycolysis/physiology* ; Gluconeogenesis/physiology* ; Kidney/metabolism*

BACKGROUND: Renal osteodystrophy (ROD) is a skeletal pathology associated with chronic kidney disease-mineral and bone disorder (CKD-MBD) that is characterized by aberrant bone mineralization and remodeling. ROD increases the risk of fracture and mortality in CKD patients. The underlying mechanisms of ROD remain elusive, partially due to the absence of an appropriate animal model. To address this gap, we established a stable mouse model of ROD using an optimized adenine-enriched diet and conducted exploratory analyses through ribonucleic acid sequencing (RNA-seq). METHODS: Eight-week-old male C57BL/6J mice were randomly allocated into three groups: control group ( n = 5), adenine and high-phosphate (HP) diet group ( n = 20), and the optimized adenine-containing diet group ( n = 20) for 12 weeks. We assessed the skeletal characteristics of model mice through blood biochemistry, microcomputed tomography (micro-CT), and bone histomorphometry. RNA-seq was utilized to profile gene expression changes of ROD. We elucidated the functions of differentially expressed genes (DEGs) using gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and gene set enrichment analysis (GSEA). DEGs were validated via quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: By the fifth week, adenine followed by an HP diet induced rapid weight loss and high mortality rates in the mouse group, precluding further model development. Mice with optimized adenine diet-induced ROD displayed significant abnormalities in serum creatinine and blood urea nitrogen levels, accompanied by pronounced hyperparathyroidism and hyperphosphatemia. The femur bone mineral density (BMD) of the model mice was lower than that of control mice, with substantial bone loss and cortical porosity. ROD mice exhibited substantial bone turnover with an increase in osteoblast and osteoclast markers. Transcriptomic profiling revealed 1907 genes with upregulated expression and 723 genes with downregulated expression in the femurs of ROD mice relative to those of control mice. Pathway analyses indicated significant enrichment of upregulated genes in the sphingolipid metabolism pathway. The significant upregulation of alkaline ceramidase 1 ( Acer1 ), alkaline ceramidase 2 ( Acer2 ), prosaposin-like 1 ( Psapl1 ), adenosine A1 receptor ( Adora1 ), and sphingosine-1-phosphate receptor 5 ( S1pr5 ) were successfully validated in mouse femurs by qRT-PCR. CONCLUSIONS Optimized adenine diet mouse model may be a valuable proxy for studying ROD. RNA-seq analysis revealed that the sphingolipid metabolism pathway is likely a key player in ROD pathogenesis, thereby providing new avenues for therapeutic intervention.
Animals ; Mice ; Chronic Kidney Disease-Mineral and Bone Disorder/genetics* ; Male ; Disease Models, Animal ; Mice, Inbred C57BL ; Sphingolipids/metabolism* ; Transcriptome/genetics* ; Signal Transduction/genetics* ; X-Ray Microtomography ; Adenine