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*

Acute kidney injury (AKI) affects more than 20% of hospitalized patients and is a significant contributor to morbidity and mortality, primarily due to ischemia-reperfusion injury (IRI), which is one of the leading causes of AKI. IRI not only exacerbates the immediate impact of AKI but also facilitates its progression to chronic kidney disease (CKD) and, in cases of preexisting CKD, to end-stage renal disease (ESRD). One of the critical pathological processes associated with IRI-AKI is cellular senescence, characterized by an irreversible arrest in the cell cycle, morphological and chromatin organization changes, altered transcriptional and metabolic profiles, and the development of a hypersecretory phenotype known as the senescence-associated secretory phenotype (SASP). The SASP amplifies senescence signals in surrounding normal cells through senescence-related pathways, contributing to tissue damage, fibrosis, and chronic inflammation. This review provides an overview of the defining features of senescent cells and explores the fundamental mechanisms underlying senescent cell generation following IRI. We elucidate the pivotal roles of cellular senescence in the transition from IRI-AKI to chronic kidney injury. Furthermore, we discuss emerging therapies targeting cellular senescence, including senolytics and senomorphics, which have shown promising results in both preclinical and clinical settings. These therapies position cellular senescence as a crucial target for the treatment of IRI in the kidneys. Additionally, advancements in single-cell sequencing technology and artificial intelligence-assisted drug screening are expected to accelerate the discovery of novel senescent biomarkers and synotherapeutics, paving the way for optimized and personalized therapeutic interventions.
Humans ; Cellular Senescence/physiology* ; Reperfusion Injury/pathology* ; Acute Kidney Injury/pathology* ; Animals ; Kidney/metabolism* ; Senescence-Associated Secretory Phenotype/physiology*

Cellular senescence, stable cell cycle arrest that can be triggered in normal cells in response to various intrinsic and extrinsic stressors, has been highlighted as one of the most important mechanisms involved in kidney diseases. It not only serves as a fundamental biological process promoting normal organogenesis and successful wound repair but also contributes to organ dysfunction, tissue fibrosis, and the generalized aging phenotype. Moreover, senescent cells exhibit reduced regenerative capacity, which impairs renal function recovery from injuries. Importantly, senescent cells are involved in immune regulation via secreting a diverse array of proinflammatory and profibrotic factors known as senescence-associated secretory phenotype (SASP) with autocrine, paracrine, and endocrine activities. Thus, eliminating detrimental senescent cells or inhibiting SASP production holds great promise for developing innovative therapeutic strategies for kidney diseases. In this review, we summarize the current knowledge of the intricate mechanisms and hallmarks of cellular senescence in kidney diseases and emphasize novel therapeutic targets, including epigenetic regulators, G protein-coupled receptors, and lysosome-related proteins. Particularly, we highlight the recently identified senotherapeutics, which provide new therapeutic strategies for treating kidney diseases.
Humans ; Cellular Senescence/genetics* ; Kidney Diseases/pathology* ; Senescence-Associated Secretory Phenotype/physiology* ; Animals ; Epigenesis, Genetic/physiology*

Nuclear receptor co-activator 4 (NCOA4) acts as a selective cargo receptor that binds to ferritin, a cytoplasmic iron storage complex. By mediating ferritinophagy, NCOA4 regulates iron metabolism and releases free iron in the body, thus playing a crucial role in a variety of biological processes, including growth, development, and metabolism. Recent studies have shown that NCOA4-mediated ferritinophagy is closely associated with the occurrence and development of iron metabolism-related diseases, such as liver fibrosis, renal cell carcinoma, and neurodegenerative diseases. In addition, a number of clinical drugs have been identified to modulate NCOA4-mediated ferritinophagy, significantly affecting disease progression and treatment efficacy. This paper aims to review the current research progress on the role of NCOA4-mediated ferritinophagy in related diseases, in order to provide new ideas for targeted clinical therapy.
Humans ; Nuclear Receptor Coactivators/physiology* ; Ferritins/metabolism* ; Animals ; Neurodegenerative Diseases/metabolism* ; Iron/metabolism* ; Autophagy/physiology* ; Liver Cirrhosis/metabolism* ; Carcinoma, Renal Cell/metabolism* ; Kidney Neoplasms/physiopathology*

Persistent inflammation plays a pivotal role in the initiation and progression of renal fibrosis. Activation of the pattern recognition receptor retinoic acid-inducible gene-I (RIG-I) is implicated in the initiation of inflammation. This study aimed to investigate the upstream mechanisms that regulates the activation of RIG-I and its downstream signaling pathway. Eight-week-old male C57BL/6 mice were used to establish unilateral ureteral obstruction (UUO)-induced renal fibrosis model, and the renal tissue samples were collected 14 days later for analysis. Transforming growth factor-β (TGF-β)-treated mouse renal tubular epithelial cells were used in in vitro studies. The results demonstrated that, compared to the control group, UUO kidney exhibited significant fibrosis, which was accompanied by the increases of RIG-I, p-NF-κB p65 and inflammatory cytokines, such as TNF-α and IL-1β. Additionally, the protein level of the E3 ubiquitin ligase RNF125 was significantly downregulated and predominantly localized in the renal tubular epithelial cells. Similarly, the treatment of tubular cells with TGF-β induced the increases in RIG-I, p-NF-κB p65 and inflammatory cytokines while decreasing RNF125. Co-immunoprecipitation (Co-IP) assays confirmed that RNF125 was able to interact with RIG-I. Overexpression of RNF125 promoted the ubiquitination of RIG-I, and accelerated its degradation via the ubiquitin-proteasome pathway. Overexpression of RNF125 in UUO kidneys and in vitro tubular cells effectively mitigated the inflammatory response and renal fibrosis. In summary, our results demonstrated that the decrease in RNF125 under pathological conditions led to reduction in RIG-I ubiquitination and degradation, activation of the downstream NF-κB signaling pathway and increase in inflammatory cytokine production, which promoted the progression of renal fibrosis.
Animals ; Fibrosis ; Male ; Ubiquitination ; Mice ; Mice, Inbred C57BL ; DEAD Box Protein 58 ; Ubiquitin-Protein Ligases/physiology* ; Inflammation/metabolism* ; Ureteral Obstruction/complications* ; Kidney/pathology* ; Signal Transduction ; Transforming Growth Factor beta/pharmacology*

OBJECTIVE: Previous studies have shown that insomnia is closely related to erectile dysfunction（ED）. However, the causal relationship between them is still unclear. Mendelian randomization (MR) provides a new method for studying the relationship between the two, and the theory of heart-kidney interaction in TCM provides a new idea for exploring the causal relationship between them. METHODS: Based on the statistical data collected by genome-wide association studies (GWAS), the causal relationship between insomnia and ED was discussed by MR. Inverse variance weighted (IVW) is the main analysis method, and weighted median (WME), simple mode (SM), weighted mode (WM) and MR Egger method were the supplementary analysis to evaluate the causal effect. MR-Egger intercept test, Cochran Q test and leave-one-out method were used in sensitivity analysis to verify the reliability of MR results. RESULTS: Thirty-nine SNPs significantly related to insomnia were finally included for MR analysis. The results of IVW method in MR analysis showed that insomnia had a significant causal relationship with the increased risk of ED (OR = 3.111，95% CI= 1.566－6.181，P=1.193×10－3). The results obtained by MR-Egger method, WME method, WM method and SM method were consistent with IVW method in the direction of effect. The sensitivity results suggested that the results of this study were robust. CONCLUSION Our study reveals the causal relationship between insomnia and ED, which provides a new basis for future clinical practice and prevention and treatment of ED.
Causality ; Sleep Initiation and Maintenance Disorders/genetics* ; Erectile Dysfunction/genetics* ; Mendelian Randomization Analysis ; Genome-Wide Association Study ; Humans ; Male ; Heart/physiology* ; Kidney/physiology* ; Polymorphism, Single Nucleotide ; Data Interpretation, Statistical

BACKGROUND: Heavy metals are significant risk factors for kidney function. Numerous studies have shown that exposure to heavy metals negatively correlates with kidney function through oxidative stress pathways, and serum α-klotho is linked to oxidative stress. However, the role of α-klotho in the relationship between blood lead, mercury, and kidney function remains unclear. METHOD: This study evaluated the mediating role of alpha-klotho in the relationship between lead, mercury and renal function, using data from the 2007-2016 National Health and Nutrition Examination Survey (NHANES) in U.S. adults aged 40-79. The sample included 11,032 participants, with blood lead, mercury, α-klotho, and other relevant covariates measured. Inductively coupled plasma mass spectrometry was used to assess blood lead and mercury levels, and enzyme-linked immunosorbent assay (ELISA) was employed to measure serum α-klotho. Kidney function was evaluated using estimated glomerular filtration rate (eGFR) based on creatinine levels. Multivariable linear regression was conducted to analyze the relationships between blood lead, mercury, α-klotho, and eGFR. A mediation analysis model was used to assess whether α-klotho influenced these associations. RESULTS: We observed a significant association between blood lead and eGFR. Mediation analysis revealed that α-klotho accounted for 12.76% of the relationship between serum lead and eGFR in the NHANES population. Subgroup analysis showed that α-klotho mediated 12.43%, 6.87%, 21.50% and 5.44% of the relationship between blood lead and eGFR in women, middle-aged adults (40-59 years old), without cardiovascular disease and hypertension, respectively. However, α-klotho did not mediate the relationship between blood mercury and eGFR in terms of gender or age. This newly identified pathway may provide valuable insights for the prevention and treatment mechanisms related to kidney function impairment. CONCLUSION We found that blood lead was associated with renal function. According to the results of subgroup analysis, for blood lead, serum α-klotho mediated the association in females, middle aged 60-79 years. The relationship between blood mercury and renal function was not clinically significant, and serum α-Klotho mediated the relationship between blood mercury and renal function without significant clinical significance.
Humans ; Middle Aged ; Lead/blood* ; Female ; Klotho Proteins ; Male ; Aged ; Adult ; Mercury/blood* ; Glomerular Filtration Rate ; Nutrition Surveys ; United States ; Kidney/physiology* ; Glucuronidase/blood* ; Environmental Pollutants/blood*

OBJECTIVE: To investigate the therapeutic efficacy of cinnamaldehyde (CA) on systemic Candida albicans infection in mice and to provide supportive data for the development of novel antifungal drugs. METHODS: Ninety BALB/c mice were randomly divided into 3 groups according to a random number table: CA treatment group, fluconazole (positive control) group, and Tween saline (negative control) group, with 30 mice in each group. Initially, all groups of mice received consecutive intraperitoneal injections of cyclophosphamide at 200 mg/kg for 2 days, followed by intraperitoneal injection of 0.25 mL C. albicans fungal suspension (concentration of 1.0 × 10⁷ CFU/mL) on the 4th day, to establish an immunosuppressed systemic Candida albicans infection animal model. Subsequently, the mice were orally administered CA, fluconazole and Tween saline, at 240, 240 mg/kg and 0.25 mL/kg respectively for 14 days. After a 48-h discontinuation of treatment, the liver, small intestine, and kidney tissues of mice were collected for fungal direct microscopic examination, culture, and histopathological examination. Additionally, renal tissues from each group of mice were collected for (1,3)- β -D-glucan detection. The survival status of mice in all groups was monitored for 14 days of drug administration. RESULTS: The CA group exhibited a fungal clearance rate of C. albicans above 86.7% (26/30), significantly higher than the fluconazole group (60.0%, 18/30, P<0.01) and the Tween saline group (30.0%, 9/30, P<0.01). Furthermore, histopathological examination in the CA group revealed the disappearance of inflammatory cells and near-normal restoration of tissue structure. The (1,3)-β-D-glucan detection value in the CA group (860.55 ± 126.73 pg/mL) was significantly lower than that in the fluconazole group (1985.13 ± 203.56 pg/mL, P<0.01) and the Tween saline group (5910.20 ± 320.56 pg/mL, P<0.01). The mouse survival rate reached 90.0% (27/30), higher than the fluconazole group (60.0%, 18/30) and the Tween saline group (30.0%, 9/30), with a significant difference between the two groups (both P<0.01). CONCLUSIONS CA treatment exhibited significant therapeutic efficacy in mice with systemic C. albicans infection. Therefore, CA holds potential as a novel antifungal agent for targeted treatment of C. albicans infection.
Animals ; Acrolein/pharmacology* ; Candida albicans/physiology* ; Mice, Inbred BALB C ; Candidiasis/pathology* ; Antifungal Agents/therapeutic use* ; Mice ; Fluconazole/therapeutic use* ; Kidney/drug effects* ; Female

OBJECTIVES: Pyroptosis plays a critical role in tubulointerstitial lesions of diabetic kidney disease (DKD). Annexin A2 (ANXA2) is involved in cell proliferation, apoptosis, and adhesion and may be closely related to DKD, but its specific mechanism remains unclear. This study aims to investigate the role and molecular mechanism of ANXA2 in high glucose-induced pyroptosis of renal tubular epithelial cells, providing new targets for DKD prevention and treatment. METHODS: Human renal tubular epithelial HK-2 cells were divided into a normal glucose group (5.5 mmol/L), a high glucose group (30.0 mmol/L), and a osmotic control group (24.5 mmol/L mannitol+5.5 mmol/L glucose). ANXA2 expression was modulated by overexpression of plasmids and small interfering RNA (siRNA). Cell proliferation was measured by 5-ethynyl-2'-deoxyuridine (EdU) assay, apoptosis by flow cytometry, and ANXA2, p50, and p65 subcellular localization by immunofluorescence. Western blotting was employed to detect α-smooth muscle actin (α-SMA), fibronectin (FN), and collagen type IV (Col-IV). Real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting were used to analyze nuclear factor-κB (NF-κB) subunits p50/p65 and the pyroptosis pathway factors NLR family Pyrin domain containing 3 (NLRP3), caspase-1, inferleukin (IL)-1β, and IL-18. Protein interactions between ANXA2 and p50/p65 were examined by co-immunoprecipitation, while chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were used to examine NF-κB binding to the ANXA2 promoter. RESULTS: High glucose upregulated ANXA2 expression and promoted its nuclear translocation (P<0.01). High glucose reduced cell proliferation, increased apoptosis, and elevated α-SMA, FN, and Col-IV expression (all P<0.05); ANXA2 overexpression aggravated these effects (all P<0.05), while ANXA2 knockdown reversed them (all P<0.05). High glucose activated NF-κB and increased NLRP3, caspase-1, L-1β, and IL-18 mRNA and protein expression (all P<0.05); ANXA2 overexpression further enhanced this, whereas knockdown suppressed NF-κB activation and downstream factors (all P<0.05). Co-immunoprecipitation confirmed ANXA2 directly binds the NF-κB subunit p65. ChIP assays revealed p65 binds specifically to ANXA2 promoter regions (ChIP-2, ChIP-4, and ChIP-6), and luciferase activity in corresponding mutant constructs (M2, M4, and M6) was significantly increased versus controls (all P<0.05), confirming positive transcriptional regulation of ANXA2 by p65. CONCLUSIONS ANXA2 and NF-κB form a positive feedback loop that sustains NLRP3 inflammasome activation, promotes pyroptosis pathway activation, and aggravates high glucose-induced renal tubular epithelial cell injury. Targeting ANXA2 or blocking its interaction with p65 may be a novel strategy to slow DKD progression.
Humans ; Pyroptosis/drug effects* ; Annexin A2/physiology* ; Epithelial Cells/cytology* ; Kidney Tubules/cytology* ; Glucose/pharmacology* ; Diabetic Nephropathies/metabolism* ; NF-kappa B/metabolism* ; Cell Line ; Cell Proliferation ; Transcription Factor RelA/metabolism* ; Feedback, Physiological

Kidney fibrosis is the final common pathway of virtually all chronic kidney disease (CKD). However, despite great progress in recent years, no targeted antifibrotic therapies have been approved. Epidemiologic, clinical, and molecular evidence suggest that aging is a major contributor to the increasing incidence of CKD. Senescent renal tubular cells, fibroblasts, endothelial cells, and podocytes have been detected in the kidneys of patients with CKD and animal models. Nonetheless, although accumulated evidence supports the essential role of cellular senescence in CKD, the mechanisms that promote cell senescence and how senescent cells contribute to CKD remain largely unknown. In this review, we summarize the features of the cellular senescence of the kidney and discuss the possible functions of senescent cells in the pathogenesis of kidney fibrosis. We also address whether pharmacological approaches targeting senescent cells can be used to retard the the progression of kidney fibrosis.
Humans ; Cellular Senescence/physiology* ; Fibrosis ; Renal Insufficiency, Chronic/pathology* ; Kidney/pathology* ; Animals