Vitexin (VI) is a naturally occurring flavonoid derived from the leaves and seeds of Vitex, recognized for its strong antioxidant properties. This study aims to explore its effects on renal ischemia-reperfusion injury (IRI) and investigate the underlying mechanisms. We utilized hypoxia-reoxygenation (H/R) models with HK-2 cell lines and renal ischemia-reperfusion (I/R) models in mice, applying vitexin preconditioning to assess its influence on renal IRI. Our findings reveal that vitexin mitigated oxidative stress, decreased cell apoptosis, and reduced the expression of renal damage indicators such as kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), along with an overall improvement in renal function. To further investigate the mechanism, we used network pharmacology and molecular docking techniques to predict potential vitexin targets in renal IRI. Results from Western blotting and immunofluorescence assays indicate that vitexin may promote mitophagy by suppressing the phosphorylation of the pivotal p38 protein in the p38/MAPK signaling pathway, offering protection against renal IRI. The findings indicate that vitexin could potentially be used as a therapeutic agent to alleviate renal IRI.

Diabetic nephropathy (DN) is a common microvascular complication of diabetes. Mitochondrial dysfunction in the kidney caused by diabetes has previously been linked to the pathogenesis of DN. By mass spectrometry, we identified characteristic proteins of DN from the renal mitochondria in mouse model. To identify the core proteins among them, Mendelian randomization (MR) analysis, microarray data validation, and drug-target interaction analysis were employed. MR analysis found that 189 candidate targets had a causal link with DN risk factors (estimated glomerular filtration rate (eGFR), urinary albumin excretion, and serum creatinine). After systematic analysis, we validated that SLC25A16, CTNND1, C2CD2L, ALDH3A2, NEU1, APEH, CORO1A, NUDT19, and NDUFA4L2 are the core proteins with promising druggability in DN. This study suggests the feasibility of using MR analysis for DN drug target screening, and provides potential insights into mitochondrial dysfunction research, which may contribute to further DN pathogenesis exploration.

Cisplatin (CP) has been used as an effective chemotherapy drug for different types of cancers. Despite its therapeutic benefits, the clinical utility of CP is often hindered by adverse effects, notably acute kidney injury (AKI), which restricts its widespread application. Dihydromyricetin (DHM) is a flavonoid acquired from Ampelopsis grossedentata, exhibiting a range of pharmacological activities. The major objective of this research was to examine the possible molecular mechanism involved in CP-induced AKI and the protective function of DHM.

In this study, the protective function of DHM against CP-induced AKI was assessed in both mice and HK-2 cells. Kidney dysfunction parameters and renal morphology were evaluated to ascertain the extent of protection. Additionally, proteomics techniques were employed to investigate the protective effect of DHM and elucidate the underlying molecular mechanisms involved in mitigating CP-induced AKI. In addition, protein levels of epidermal growth factor receptor (EGFR), p-EGFR, heat shock protein 27 (HSP27), p-HSP27, STAT3, and p-STAT3 in renal tissues were investigated. Furthermore, an EGFR-blocking agent (gefitinib) or si-RNA of HSP27 was used to study the effects of inhibiting EGFR or HSP27 on CP-induced renal injury.

DHM decreased blood urea nitrogen (BUN) and creatinine in serum, alleviated renal morphological injury and downregulated the expression of CP-induced kidney injury molecule-1 and neutrophil gelatinase-related lipocalin. Proteomic data revealed HSP27 as a potential therapeutic target for AKI. DHM treatment resulted in the downregulation of EGFR, HSP27, and STAT3 phosphorylation, ultimately mitigating CP-induced AKI. In addition, the inhibition of EGFR or HSP27 reduced mitochondria-mediated apoptosis and CP-induced cell damage in HK-2 cells.

DHM effectively inhibited CP-induced oxidative stress, inflammation, and mitochondria-mediated apoptosis through the EGFR/HSP27/STAT3 pathway.

Kidney function abnormalities is a common complication following ischemic stroke. Lipocalin 2 (LCN2) is currently a well-recognized specific biomarker of tubular injury. However, the role of LCN2 in kidney function abnormalities following stroke remains elusive. The sympathetic nervous system plays a crucial role in linking the brain and kidney. However, whether the kidney sympathetic nervous system regulates the expression of LCN2 following ischemic stroke has not been identified.

In this study, we established a middle cerebral artery occlusion (MCAO) model to induce ischemic stroke in mice. Renal function was assessed 24 h after cerebral ischemia-reperfusion injury. Transcriptomic sequencing of kidney tissue was performed to identify potential pathological mechanisms. The role of LCN2 in post-stroke renal injury was investigated using renal tubule-specific LCN2 knockout mice and a combination of qPCR, western blotting, immunofluorescence, and transmission electron microscopy. In addition, renal denervation (RDN) was used to explore the relationship between sympathetic nerves and the expression of renal LCN2.

Ischemic stroke significantly exhibits renal functional impairment 24 h after reperfusion. Notably, RNA sequencing and Western blotting revealed a markedly increased expression of renal LCN2 following ischemic stroke. Renal tubular Lcn2-specific knockout significantly ameliorated the occurrence of kidney function abnormalities after stroke. Subsequently, we observed that the activation of renal sympathetic nerves upregulates LCN2 and induces kidney function abnormalities after stroke.

These findings reveal a neural pathway in which the sympathetic nervous system upregulates LCN2, providing potential therapeutic strategies for renal protection following ischemic stroke.

The kidney, vital for metabolic balance, faces risks of severe diseases if dysfunctional. The glomerular filtration barrier (GFB), crucial for blood filtration, disrupts in conditions like diabetic nephropathy or nephritides, resulting in proteinuria or even renal failure. Monitoring GFB integrity is essential for early diagnosis or prognostic monitoring. However, current methods lack effective contrast agents for precise, non-invasive GFB imaging. As near-infrared-II (NIR-II) imaging offers promising imaging quality due to its deep tissue penetration and high resolution/contrast while albumin servers as an efficient biomarker for GFB disruption, developing NIR-II dyes with inherent albumin-targeting moiety, will provide real-time imaging of GFB disruption. Here, we adopt albumin-seeking cyanine dye to high-resolution image endogenous albumin in mouse models, facilitating detecting even mild disruptions with trace proteinuria. Notably, our strategy can determine albuminuria by real time imaging without the need to collect urine. Albumin-seeking dyes also enable fast and accurate quantitative measurement of microalbuminuria from patients. These dyes could revolutionize diagnostics, offering rapid, sensitive in vivo imaging of microalbuminuria and diverse clinical applications.

Mitochondrial dysfunction-induced oxidative stress is a key pathogenic factor in acute kidney injury (AKI). Despite this, current mitochondrial-targeted antioxidant therapies have shown limited efficacy in clinical settings. In this study, we introduce a novel renal-clearable and mitochondria-targeted antioxidant nanozyme (TPP@RuCDzyme) designed to precisely modulate mitochondrial oxidative stress and mitigate AKI progression. TPP@RuCDzyme was synthesized by integrating ruthenium-doped carbon dots (CDs) with triphenylphosphine (TPP), a mitochondria-targeting moiety. This nanozyme system exhibits cascade enzyme-like activities, mimicking superoxide dismutase (SOD) and catalase (CAT), to efficiently convert cytotoxic superoxide (O2•-) and hydrogen peroxide (H2O2) into non-toxic water (H2O) and oxygen (O2). This dual-enzyme mimicry effectively alleviates mitochondrial oxidative damage, restores mitochondrial function, and inhibits apoptosis. Compared to RuCDzyme alone, TPP@RuCDzyme demonstrated significantly enhanced efficacy in alleviating glycerol-induced AKI by inhibiting oxidative stress. By leveraging the catalytic activity derived from the integration of CDs and a metallic element, this study presents a promising therapeutic strategy for AKI and other renal diseases associated with mitochondrial dysfunction.

Glabridin, a bioactive compound extracted from licorice, exhibits anti-inflammatory and antioxidative stress effects. It has rarely been reported in hemorrhagic shock (HS)-induced acute kidney injury (AKI). Here, the effects and potential mechanisms of Glabridin on HS-induced kidney injury was investigated. The active ingredient target network of licorice for HS-induced acute kidney injury was analyzed using network pharmacology. The study also examined the target gene-related biological processes and signaling pathways. To explore the impact of Glabridin on the kidney, a HS-induced rat model was established by femoral artery bleeding following tail vein injection of Glabridin. Glabridin improved kidney function evidenced by reduced levels of creatinine, urea nitrogen, neutrophil gelatinase-associated lipocalin in the serum, and the urinary protein/creatinine ratio in HS rats. This was inseparable from the inhibitory effect on apoptosis and kidney tubule injury. In addition, the protection of Glabridin on mitochondrial function was evident in the improvement of mitochondrial morphology, reduction of reactive oxygen species, increase in adenosine triphosphate, and upregulation of peroxisome proliferator-activated receptor γ coactivator 1-alph. These effects help reduce inflammation in kidney tissue. Hypoxia/reoxygenation-induced HK-2 cells were studied in vitro, and the same results were obtained in the cell model. Mechanically, Glabridin activated the Nrf2/HO-1 signaling pathway in vivo and in vitro, which may be a potential mechanism through which Glabridin protects kidney tissue. This study revealed the preventive effect of Glabridin on the kidney of HS rats, and provided insights for the development of Glabridin as a small molecule drug.

Renal ischemia-reperfusion injury (RIRI) is a significant cause of acute kidney injury(AKI) and delayed graft function(DGF), impacting post-transplant outcomes. Mitochondrial dynamics, in particular fission and fusion, play a pivotal role in the cellular response to RIRI. The modulation of these dynamics represents a potential therapeutic target. Schisandrin B (Sch B), a component derived from traditional Chinese medicine, has shown protective roles in various organ injuries, but its effect on RIRI through mitochondrial dynamics remains unexplored.

This study explores the previously uninvestigated role of Sch B in modulating mitochondrial dynamics as a potential means of alleviating RIRI. By focusing on mitochondrial fission and fusion, this research provides novel insights into the therapeutic potential of Sch B, distinguishing it from existing approaches.

HK-2 cells were treated with hypoxia/reoxygenation (HR) in order to simulate renal ischemia-reperfusion injury (RIRI) in vitro. In vivo, mice underwent renal ischemia followed by reperfusion, which allowed for the simulation of the injury. Sch B's impact on mitochondrial dynamics, apoptosis, and oxidative stress was assessed through mitochondrial morphology assays, Western blotting for mitochondrial and apoptotic markers, TUNEL staining, and measurement of reactive oxygen species. Key molecular interactions were explored via Western blotting, molecular docking, SPR, and cellular thermal shift assays. In vivo, renal pathological damage was evaluated using HE, PAS, and TUNEL staining, while immunohistochemistry and immunofluorescence were employed to detect the expression levels of mitochondrial dynamics proteins and p-AKT1.

First, we unveiled that Schisandrin B (Sch B) significantly mitigated oxidative stress and apoptosis in HK-2 cells subjected to hypoxia-reoxygenation conditions. Sch B pretreatment notably enhanced cell viability and mitochondrial function, demonstrating its superior antioxidant capabilities compared to NAC. Second, we discovered that Sch B's protective effects involve regulating mitochondrial dynamics by decreasing fission markers, such as DRP1, while increasing fusion proteins, including OPA1 and MFN2. Furthermore, our studies revealed that Sch B directly binds to AKT1, promoting its phosphorylation and localization to mitochondria, thereby enhancing mitochondrial resilience. Finally, we demonstrated that in vivo administration of Sch B reduced renal damage and apoptosis in mouse models of renal ischemia-reperfusion injury (RIRI), while immunohistochemical analyses unveiled its role in promoting mitochondrial fusion and reducing fission, marking a significant advancement in understanding Sch B's therapeutic potential in RIRI.

Our findings demonstrate for the first time that Sch B directly interacts with AKT1 protein, enhancing its phosphorylation and promoting mitochondrial localization. This innovative mechanism reduces oxidative stress, apoptosis, and mitochondrial fission, highlighting Sch B's unique capability to modulate mitochondrial dynamics in RIRI. These results establish Sch B as a promising therapeutic agent, offering a new dimension in the management of RIRI by targeting mitochondrial health.

Ischemia-reperfusion injury stands as a primary instigator of acute kidney injury (AKI), prominently driven by oxidative stress. Among the critical antioxidant defenses is glutathione peroxidase 3 (GPX3), an enzyme generated by renal tubular epithelial cells. Our prior investigations have unveiled a substantial downregulation of GPX3 in renal tissues gleaned from AKI patients and murine models. This study aims to investigate the role of tubular cell-specific Gpx3 deletion on ischemia-reperfusion injury-induced AKI (IRI-AKI) in a murine model and delineate the potential underlying mechanisms. By generating renal tubular epithelial cell-specific Gpx3 knockout mice and inducing IRI-AKI, we assessed a spectrum of kidney injury indices including renal function, oxidative stress, apoptosis and mitochondrial dynamics. Additionally, we conducted transcriptome sequencing and bioinformatics analyses. The outcomes underscore that the deficiency of GPX3 in tubular cells exacerbates tubular injury, renal dysfunction, oxidative stress, apoptosis, and mitochondrial dynamic disturbances in the context of IRI-AKI. Sequencing and bioinformatics analysis suggest that the Gpx3 deletion predominantly impacts pathways associated with metabolism and inflammation. In conclusion, the tubular cell-specific deficiency of GPX3 exacerbates renal injury by intensifying oxidative stress, fostering mitochondrial impairment, perturbing metabolic processes and fueling inflammation. The targeted restoration of GPX3 in the renal tubular emerges as a potential therapeutic avenue for mitigating IRI-AKI.

Acute kidney injury (AKI) is characterized by high morbidity and mortality globally and serves as an independent risk factor for chronic kidney disease. Oxidative stress is the main pathogenic mechanism leading to acute kidney injury (AKI) and subsequent renal failure, which is characterized by excessive reactive oxygen species (ROS) and mitochondrial dysfunction. Treatment options for AKI remain supportive care, it is urgent to develop more viable therapeutic strategies. In this study, we engineered a nanodrug delivery system aiming to achieve precise treatment of AKI. The nanocarriers (Apt-NS) exhibited excellent serum stability and biocompatibility and were capable of specifically recognizing AKI renal tubular cells. Apt-NS were loaded with baicalein (BAI) to form a nanodrug delivery system (Apt-NS-BAI). In comparison to the BAI, Apt-NS-BAI demonstrated more pronounced effects in improving cell viability, scavenging ROS and anti-apoptosis. Simultaneously, in vivo animal experiments also confirmed that Apt-NS-BAI could recognize the injury site and exert biological functions of anti-apoptosis and alleviating renal damage. Overall, this study successfully constructed a nanodrug delivery system with the ability to target AKI renal tubular cells, enabling accurate and efficient delivery of baicalein to injury site and exerting protective functions against oxidative stress. This research offers novel insights into the precision treatment of AKI and contributes to the acceleration of the application of nanotechnology in kidney diseases.

Clerodendranthus spicatus (CS) and Cordyceps cicadae (CC) are both medicine and food. They have long been used to treat kidney disease, but their mechanisms for treating hyperuricemic nephropathy (HN) are not yet clear.

We investigated the effect and mechanism of Clerodendranthus spicatus-Cordyceps cicadae (CS-CC) in HN treatment.

We detected the chemical profiling of CS-CC freeze-dried powder, drug-containing serum and drug-containing intracellular fluid by UHPLC-Q Exactive Orbitrap-HRMS. We explored the effective components as well as underlying mechanisms of CS-CC in HN treatment via network pharmacological analysis. We constructed HN rat models induced by gavaging potassium oxonate and uric acid (UA) for three weeks, and performed biochemical and pathological tests as well as histological observation. The expressions of fibrosis-associated proteins were quantitatively analyzed using immunohistochemistry staining and western blot analysis. For in vitro studies, we measured the metabolic fluxes in UA-treated HK-2 cells using Seahorse XFe24 analyzer and flow cytometric analysis. Mitophagy-associated proteins were evaluated using immunofluorescence co-localization analysis and western blot analysis.

A total of 14 simultaneous constituents of CS-CC in vivo and in vitro were identified. Network pharmacological analysis highlighted CS-CC regulated mitophagy in HN. CS-CC treatment effectively enhanced renal function and ameliorate renal fibrosis in HN rats. We found PINK1-mediated mitophagy was suppressed in HN, while CS-CC treatment could restore cellular metabolism, activate mitophagy and protect tubular epithelial cells in HN.

PINK1-mediated mitophagy was significantly inhibited in HN, whereas CS-CC treatment demonstrated remarkable efficacy in attenuating renal fibrosis and promoting mitophagy to protect tubular epithelial cells in HN.

This study aims to investigate the mechanisms of MSC therapy for acute kidney injury, focusing on the regulation of mitochondrial function and pyroptosis in renal tubular epithelial cells (RTECs).

An in vivo ischemia/reperfusion (I/R) model was used to assess the effects of MSC treatment on mitochondrial membrane potential, mitochondrial function, cell pyroptosis, and PGC-1α expression in RTECs.

MSCs significantly improved mitochondrial function in RTECs by upregulating PGC-1α expression, regulating mitochondrial fusion and fission proteins, reducing mitochondrial ROS production, and suppressing NLRP3 inflammasome activation. Furthermore, MSC treatment reduced the levels of pyroptotic markers, such as IL-18, and exhibited a marked anti-fibrotic effect in the long-term. These findings suggest that MSCs not only repair acute kidney injury but also offer long-term protection against fibrosis.

MSCs improve the repair of acute kidney injury by modulating mitochondrial function and inhibiting pyroptosis, providing new theoretical support for MSC-based therapies in AKI treatment.

Aims: The limited therapeutic options for diabetic tubulopathy (DT) in early diabetic kidney disease (DKD) reflect the difficulty of targeting renal tubular compartment. While renin-angiotensin-aldosterone system (RAS) inhibitors are commonly utilized in the management of DKD, how intrarenal RAS contributes to diabetic tubular injury is not fully understood. Mitochondrial disruption and reactive oxygen species (ROS) overgeneration have been involved in diabetic tubular injury. Herein, we aim to test the hypothesis that angiotensin-converting enzyme (ACE)-dependent intrarenal angiotensin II (AngII) disrupts tubular mitochondrial membranous homeostasis and causes excessive ROS generation in DT. Results: Mice suffered from renal tubular mitochondrial disruption and ROS overgeneration following high-fat diet/streptozocin-type 2 diabetic induction. Intrarenal AngII generation is ACE-dependent in DT. Local AngII accumulation in renal tissues was achieved by intrarenal artery injection. ACE-dependent intrarenal AngII-treated mice exhibit markedly elevated levels of makers of tubular injury. CTP: Phosphoethanolamine cytidylyltransferase (PCYT2), the primary regulatory enzyme for the biosynthesis of phosphatidylethanolamine, was enriched in renal tubules according to single-cell RNA sequencing. ACE-dependent intrarenal AngII-induced tubular membranous disruption, ROS overgeneration, and PCYT2 downregulation. The diabetic ambiance deteriorated the detrimental effect of ACE-dependent intrarenal AngII on renal tubules. Captopril, the ACE inhibitor (ACEI), showed efficiency in partially ameliorating ACE-dependent intrarenal AngII-induced tubular deterioration pre- and post-diabetic induction. Innovation and Conclusion: This study uncovers a critical role of ACE-dependent intrarenal AngII in mitochondrial membranous disruption, ROS overgeneration, and PCYT2 deficiency in diabetic renal tubules, providing novel insight into DT pathogenesis and ACEI-combined therapeutic targets. Antioxid. Redox Signal. 42, 767-786.

To ascertain the connection between normal-range urinary albumin-to-creatinine ratio (UACR) and all-cause mortality (ACM) among diabetic adults with preserved eGFR.

We used data from the 2003-2018 National Health and Nutrition Examination Survey. Nationally representative cross-sectional survey data linked with mortality outcomes from the National Death Index. Restricted cubic spline curves (RCS) and multivariable Cox regression models alongside subgroup analyses were utilised for estimating hazard ratios (HRs) and 95% confidence intervals (Cls) for UACR-ACM interplay, adjusting for demographic, socioeconomic, biochemical, medication and medical history factors. The UACR's predictive accuracy for survival outcomes was determined through receiver operating characteristic analysis.

The RCS regression analysis showcased that there was no significant evidence to support a nonlinear relationship between normal-range UACR and ACM (p = 0.080 for nonlinearity) in participants with diabetes mellitus (DM). In the model 2 adjusted for multiple confounding variables, the HR for ACM was 1.22 (95% CI, 1.06-1.40) per 10 mg/g raise in continuous UACR and 1.50 (95%CI, 1.18-1.91) for the high UACR tertile compared to the low. Kaplan-Meier analysis showed significantly lower survival rates in the medium and high UACR groups (p < 0.001). Subgroup analysis manifested a significant UACR-body mass index (BMI) interaction (p = 0.033 for interaction).

In DM adults without overt kidney dysfunction, elevated normal-range UACR was independently related to escalated ACM, particularly in those with normal BMI. To conclude, we underscore the significance of early risk assessment in DM patients with normal-range albuminuria, even without overt kidney dysfunction.

In clinical practice, sodium-glucose transporter 2 inhibitor (SGLT2i) reduces the composite renal outcomes in patients with diabetic kidney disease (DKD). However, its effect on regulating renal mitochondria remains unclear. Mitochondrial quality control (MQC) has been identified as a key factor in DKD. Peroxiredoxin3 (Prdx3) serves as a primary antioxidant protein in mitochondria. In this study, we investigated the expression of Prdx3 in patients with DKD, diabetic mice and HK-2 cells exposed to high glucose and explored SGLT2i potential mechanism of action. The results also showed that empagliflozin (Empa) treatment improved proteinuria and ameliorated renal pathological damage. We observed that Empa has an impact on the expression of Prdx3 in diabetic mice and HK-2 cells exposed to high glucose, so does the mitochondrial dynamic proteins and mitophagy-related proteins Mfn2, Drp1, PINK1, Parkin, LC3II, and P62. In vitro experiments after transfected with pcDNA3.1(+)-Prdx3 and siPrdx3 the expression of Mfn2, Drp1, PINK1, Parkin, LC3II, and P62 changed. The expression of PINK1 decreased after the knockdown of Prdx3. Furthermore, the knockdown of PINK1 accelerated the MQC damage and weakened the protective effect of Empa. Because Empa has impacts on Prdx3, which plays a protective role by influencing MQC, we investigated the latent impact of Prdx3 deficiency on renal injury and its molecular mechanism in vivo and in vitro in DKD. Herein, we demonstrate that Empa treatment modulates MQC potentially via Prdx3 through interacting with PINK1.

Diabetes mellitus (DM) is a major cause of end-stage kidney disease (ESKD), with kidney transplantation being the preferred treatment. However, post-transplant diabetes mellitus (PTDM) increases mortality and graft loss. While PTDM and Type 2 diabetes mellitus (T2DM) share risk factors, their mechanisms differ, particularly in diabetic nephropathy (DN). This study aimed to investigate the molecular differences in PTDM by mapping the proteomes of proximal tubuli and serum in normoglycemic (NG), pre-transplant T2DM, and PTDM patients one year post-transplantation. Experimental Design Proteomic analysis was performed on microdissected proximal tubular cells and serum samples from kidney transplant recipients categorized as NG, pre-transplant T2DM, or PTDM at one year post-transplantation. Mass spectrometry was used to identify differentially expressed proteins. Data analyses were performed using gene ontology databases and pathway analysis.

Proteomic analysis revealed key differences, including significant dysregulation of mitochondrial proteins and lipid metabolism pathways in PTDM patients compared to T2DM and NG groups. Additionally, we observed distinct serum patterns of cholesterol metabolism dysregulation in PTDM, highlighting a complex interplay between fatty acid metabolism, mitochondrial dysfunction and systemic lipid dysregulation that may drive renal injury in PTDM-related DN.

This pilot study is the first to perform proteomic analysis on both microdissected tubular cells and serum from post-transplant PTDM, pre-transplant T2DM and NG transplant recipients. The proteomic differences between PTDM and T2DM could help to develop targeted therapies and early diagnostic markers, ultimately improving transplant outcomes and patient management. Further research is needed to validate these findings and explore their therapeutic potential.

Maladaptive kidney repair after injury is associated with a loss of mitochondrial homeostasis, but the underlying mechanism is largely unknown. Moreover, it remains unclear whether this mitochondrial change contributes to maladaptive kidney repair or the development of chronic kidney problems after injury. Here, we report that the transcriptional coactivator peroxisome proliferation-activated receptor γ coactivator-1α (PGC1a), a master regulator of mitochondrial biogenesis, was persistently downregulated during maladaptive kidney repair after repeated low-dose cisplatin nephrotoxicity or unilateral ischemia/reperfusion injury. Administration of the PGC1α activator ZLN005 after either kidney injury not only preserved mitochondria but also attenuated kidney dysfunction, tubular damage, interstitial fibrosis, and inflammation. PGC1α downregulation in these models was associated with p53 activation. Notably, knockout of p53 from proximal tubules prevented PGC1α downregulation, attenuated chronic kidney pathologies and minimized functional decline. Inhibition of p53 with pifithrin-α, a cell permeable p53 inhibitor, had similar effects. Mechanistically, p53 bound to the PGC1α gene promoter during maladaptive kidney repair, and this binding was suppressed by pifithrin-α. Together, our results indicate that p53 is induced during maladaptive kidney repair to repress PGC1α transcriptionally, resulting in mitochondrial dysfunction for the development of chronic kidney problems. Activation of PGC1α and inhibition of p53 may improve kidney repair after injury and prevent the development of chronic kidney problems.

Liver-derived circulating nicotinamide from nicotinamide adenine dinucleotide (NAD+) catabolism primarily feeds systemic organs for NAD+ synthesis. We surprisingly found that, despite blunted hepatic NAD+ and nicotinamide production in liver-specific nicotinamide nucleotide adenylyltransferase 1 (NMNAT1) deletion mice (liver-specific knockout [LKO]), circulating nicotinamide and extra-hepatic organs' NAD+ are unaffected. Metabolomics reveals a massive accumulation of a novel molecule in the LKO liver, which we identify as nicotinic acid riboside (NaR). We further demonstrate cytosolic 5'-nucleotidase II (NT5C2) as the NaR-producing enzyme. The liver releases NaR to the bloodstream, and kidneys take up NaR to synthesize NAD+ through nicotinamide riboside kinase 1 (NRK1) and replenish circulating nicotinamide. Serum NaR levels decline with aging, whereas oral NaR supplementation in aged mice boosts serum nicotinamide and multi-organ NAD+, including kidneys, and reduces kidney inflammation and albuminuria. Thus, the liver-kidney axis maintains systemic NAD+ homeostasis via circulating NaR, and NaR supplement ameliorates aging-associated NAD+ decline and kidney dysfunction.

Apigenin (API) is a flavonoid widely distributed in vegetables and fruits that exhibits numerous biological functions. Lipopolysaccharide (LPS), a key component of the outer membrane of Gram-negative bacteria, can cause kidney injury when released into the bloodstream. Necroptosis is a form of programmed cell death characterized by the rupture of cell membranes. Excessive occurrence of necroptosis can lead to substantial damage to cells and tissues. In the study, we discovered that API could mitigate LPS-induced kidney injury in mice and alleviate LPS-induced necroptosis in Normal Rat Kidney-52E (NRK-52E) cells by targeting the mitochondrial reactive oxygen species (mtROS)-RIPK3-MLKL pathway. Further mechanistic studies revealed that API could potentially activate the endosomal sorting complexes required for transport-III (ESCRT-III), and activated ESCRT-III could repair cell membrane rupture caused by LPS-induced necroptosis. Simultaneously, we discovered that activated ESCRT-III could promote mitophagy, which facilitates the timely removal of damaged mitochondria and reduces intracellular mtROS levels. In conclusion, our results suggested that API alleviates LPS-induced renal cell necroptosis by activating ESCRT-III-dependent membrane repair and mitophagy. Our study provides new insights into the daily dietary intake of API to alleviate kidney injury caused by LPS.

Abnormal lipid metabolism is an independent risk factor for kidney injury, significantly altering the associated gene expression, particularly in single kidney models. This study investigates the impact of high-fat diet-induced lipid metabolism on podocyte injury in uninephrectomized mice. Using targeted lipidomics analysis and podocyte-specific assays, the modification of lipid profiles attributed to a high-fat diet and the development of podocyte injury caused by lipid metabolism in mice that underwent unilateral nephrectomy were examined. Mice that underwent unilateral nephrectomy and were fed with a high-fat diet for 13 weeks exhibited progressive renal dysfunction, including the accumulation of lipid droplets in podocytes, vacuolization of tubular cells, and glomerular hypertrophy. Liquid chromatography-triple quadrupole mass spectrometry confirmed a significant increase in cholesteryl ester 20:4 levels in the podocytes of these mice. In vitro, cholesteryl ester 20:4 treatment reduced mitochondrial respiration capacity and mitochondrial glycolysis in podocytes. Furthermore, the treatment led to alterations in the protein expression levels associated with lipid metabolism and transport, mitochondrial activity, and autophagy, including ATP binding cassette subfamily A member 1 (ABCA1), carnitine palmitoyltransferase 1 A (CPT1A), acyl-CoA cholesterol acyltransferase (ACAT), nuclear respiratory factor ½ (NRF½), dynamin-1-like protein (DRP1), and p62. Transcriptome sequencing analysis revealed impaired gene expression, which was associated with the progression of renal fibrosis in unilateral nephrectomy mice with a high-fat diet. Specifically, the expression of matrix metalloproteinases and collagen genes, including fibronectin and collagen IV, was upregulated, indicating fibrosis progression. In conclusion, lipidomics analysis identifies cholesteryl ester 20:4 as a key lipid metabolite accumulating in podocytes, which is associated with mitochondrial dysfunction and abnormal autophagy. This accumulation potentially contributes to structural and functional deterioration in the kidney and highlights its role in kidney damage and its potential as a therapeutic target in metabolic kidney diseases.

Mitochondria are essential organelles for cellular function and have become a broad field of study. In cardio-renal diseases, it has been established that mitochondrial dysfunction is a primary mechanism leading to these pathologies. Under stress, mitochondria can develop stress response mechanisms to maintain mitochondrial quality control (MQC) and functions. In contrast, the perturbation of these mechanisms has been associated with the pathogenesis of several diseases. Thus, targeting specific pathways within MQC could offer a therapeutic avenue for protecting mitochondrial integrity. However, the mechanisms related to MQC and mitochondrial stress signaling in the cardio-renal axis have been poorly explored. The primary limitations include the lack of reproducibility in the experimental models of cardio-renal disease, the incomplete knowledge of molecules that generate bidirectional damage, and the temporality of the study models. Therefore, we believe that integration of all of those limitations, along with recent advances in MQC mechanisms (i.e., mitophagy), stress signaling pathways (e.g., integrated stress response, mitochondrial unfolded protein response, and mitochondrial protein import), associated pharmacology, and targeted therapeutic approaches could reveal what the deregulation of these mechanisms is like and provide ideas for generating strategies that seek to avoid the progression of cardio-renal diseases.

Diabetes mellitus (DM) is a chronic metabolic disorder marked by sustained hyperglycemia. These disturbances contribute to extensive damage across various tissues and organs, giving rise to severe complications such as vision loss, kidney failure, amputations, and higher morbidity and mortality rates. Furthermore, DM imposes a substantial economic and emotional burden on patients, families, and healthcare systems. Mitophagy, a selective process that targets the clearance of damaged or dysfunctional mitochondria, is pivotal for sustaining cellular homeostasis through mitochondrial turnover and recycling. Emerging evidence indicates that dysfunctional mitophagy acts as a key pathogenic driver in the pathogenesis of DM and its associated complications. Natural small molecules are particularly attractive in this regard, offering advantages such as low toxicity, favorable pharmacokinetic profiles, excellent biocompatibility, and a broad range of biochemical activities. This review systematically evaluates the mechanistic roles of natural small molecules-including ginsenosides, resveratrol, and berberine-in enhancing mitophagy and restoring mitochondrial homeostasis via activation of core signaling pathways (e.g., PINK1/Parkin, BNIP3/NIX, and FUNDC1). These pathways collectively ameliorate pathological hallmarks of DM, such as oxidative stress, chronic inflammation, and insulin resistance. Furthermore, the integration of nanotechnology with these compounds optimizes their bioavailability and tissue-specific targeting, thereby establishing a transformative therapeutic platform for DM management. Current evidence demonstrates that mitophagy modulation by natural small molecules not only offers novel therapeutic strategies for DM and its chronic complications but also advances the mechanistic foundation for future drug development targeting metabolic disorders.

Renal fibrosis represents the final common pathological manifestation of chronic kidney disease (CKD), yet the underlying mechanism remains elusive, and there is still a lack of effective targeted therapeutic strategy. Although previous research indicated that repressor element 1-silencing transcription factor (REST) contributed to acute kidney injury (AKI) in renal tubular epithelial cells (RTECs), its specific contribution to renal fibrosis and associated mechanisms remains largely unexplored.

Renal biopsies from CKD patients were collected to evaluate the expression of REST. Kidney-specific Rest conditional knockout (Cdh16-Cre/Restflox/flox) mice were generated and employed unilateral ureter obstruction (UUO) models to investigate the role of REST in renal fibrosis. RNA sequencing was performed to elucidate the mechanism. Mitochondrial function was evaluated by transmission electron microscopy (TEM), reactive oxygen species (ROS), oxygen consumption rates (OCR), extracellular acidifcation rate (ECAR) and adenosine triphosphate (ATP). The severity of renal fibrosis was assessed through Western blot, immunofluorescent staining and immumohistochemical staining. Bioinformatic prediction, dual luciferase reporter gene assay, point mutation and chromatin immunoprecipitation (ChIP) assay were utilized to clarify the molecular mechanism.

REST was significantly up-regulated in the kidney tissues from CKD patients, UUO-induced fibrotic mouse models and TGF-β1-incubated RTECs. Notably, kidney-specific knockout of Rest prominently alleviated renal fibrosis by improving mitochondrial energy metabolism and restoring fatty acid oxidation. Mechanically, REST disturbed mitochondrial energy metabolism through repressing the transcription of oxoglutarate dehydrogenase-like (OGDHL) via directly binding to its promotor region. Further, pharmacological inhibition of REST using the specific REST inhibitor, X5050, significantly ameliorated the progression of renal fibrosis both in vitro and in vivo.

Our explorations revealed the upregulation of REST in renal fibrosis disrupts mitochondrial energy metabolism through transcriptionally suppressing OGDHL, which may act as a promising therapeutic target for renal fibrosis.

Otto Warburg originally proposed that cancer arose from a two-step process. The first step involved a chronic insufficiency of mitochondrial oxidative phosphorylation (OxPhos), while the second step involved a protracted compensatory energy synthesis through lactic acid fermentation. His extensive findings showed that oxygen consumption was lower while lactate production was higher in cancerous tissues than in non-cancerous tissues. Warburg considered both oxygen consumption and extracellular lactate as accurate markers for ATP production through OxPhos and glycolysis, respectively. Warburg's hypothesis was challenged from findings showing that oxygen consumption remained high in some cancer cells despite the elevated production of lactate suggesting that OxPhos was largely unimpaired. New information indicates that neither oxygen consumption nor lactate production are accurate surrogates for quantification of ATP production in cancer cells. Warburg also did not know that a significant amount of ATP could come from glutamine-driven mitochondrial substrate level phosphorylation in the glutaminolysis pathway with succinate produced as end product, thus confounding the linkage of oxygen consumption to the origin of ATP production within mitochondria. Moreover, new information shows that cytoplasmic lipid droplets and elevated aerobic lactic acid fermentation are both biomarkers for OxPhos insufficiency. Warburg's original hypothesis can now be linked to a more complete understanding of how OxPhos insufficiency underlies dysregulated cancer cell growth. These findings can also address several questionable assumptions regarding the origin of cancer thus allowing the field to advance with more effective therapeutic strategies for a less toxic metabolic management and prevention of cancer.

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) preserve cardiac and renal function by mechanisms that are not completely elucidated. Among other things, SGLT2i promote nutrient-deprivation signalling, which might affect the immune function. As the fate of immune cells is controlled by their metabolism, we aimed to study the mitochondrial integrity of lymphocytes isolated from renal transplant recipients with type 2 diabetes (T2D) upon SGLT2i therapy instauration and six-month follow up. In this real-world pilot study, the mitochondrial respiration of isolated peripheral blood mononuclear cells was monitored in a Seahorse XFp extracellular-flux analyzer and cells were photographed with a confocal microscope. Mitochondrial mass, membrane potential, and superoxide content of lymphocyte subpopulations were measured by flow cytometry (MitoTrackerTM Green, TMRM, and MitoSOXTM Red probes). Leveraging in vivo conditions of immune cells, we evaluated their metabolic profiles associated with immune activation. Herein, we identified changes in redox homeostasis with sustained membrane polarization, and an increased mitochondrial biogenesis upon PHA stimulation that significantly correlated with changes in body weight and LDL-cholesterol levels, and a resultant compensatory mitochondrial function of lymphocytes. Our data suggest novel mechanisms induced by SGLT2i to modulate immune cells, which probably underlie the observed beneficial effects in kidney transplant recipients. Nonetheless, further mechanistic studies are required to extend these exploratory findings and encourage the use of this therapeutic strategy.

This study aimed to investigate the effects and molecular mechanism of PF on high glucose (HG)-induced podocyte injury. Results found that PF increased proliferation activity, decreased apoptosis, LDH, and caspase-3 levels, and increased nephrin and podocin expression in HG-induced cells. Similarly, PF improved HG-induced mitochondrial damage, decreased Ca2+ and ROS content, alleviated oxidative stress, inhibited mPTP opening, increased mitochondrial membrane potential, and decreased the expressions of Drp1, Bak, Bax, and Cytc in cytoplasm, increased the expressions of SIRT1, PGC-1α, HSP70, HK2, and Cytc in mitochondria of podocytes. The use of mPTP agonist/blocker and SIRT1 inhibitor confirmed that PF alleviates HG-induced podocyte injury by regulating mitochondrial mPTP opening through SIRT1/PGC-1α. In addition, PF affected HK2-VDAC1 protein binding to regulate mPTP opening via the SIRT1/PGC-1α pathway. In conclusion, PF-regulated HK2-VDAC1 protein binding affected mitochondrial mPTP opening and improved HG-induced podocyte injury through the SIRT1/PGC-1α pathway.

Massive proteinuria, dyslipidemia, and hypoalbuminemia induced by nephrotic syndrome (NS) secondarily affect tubular cells. We conducted an RNA sequencing (RNA-seq) analysis using a mouse model of focal segmental glomerulosclerosis to clarify the impact of NS on tubular cells.

We used transgenic mice expressing hCD25 in podocytes (Nep25) to induce NS by injecting human CD25-specific immunotoxin (LMB2) at a dose of 0.625 ng/g body weight. Seven days after LMB2 injection, we extracted RNA from the whole kidney and conducted an RNA-seq analysis. Subsequently, we conducted multiple immunostaining and in situ hybridization (ISH) of differentially expressed genes (DEGs) to identify their locations and associated cell types. We also investigated the expression levels of DEGs in an additional mouse model of NS induced by adriamycin.

After NS induction, 562 upregulated and 430 downregulated DEGs were identified using RNA-seq. An enrichment analysis revealed the upregulation of cell proliferation-related genes. We observed significant upregulation of Foxm1, a transcription factor linked to cell proliferation. Immunostaining and ISH showed that various tubular cells expressed Mki67 and Foxm1 during NS development. The adriamycin-induced NS model also demonstrated the upregulation of Mki67 and Foxm1 in tubular cells.

NS induced the upregulation of cell proliferation-related genes in tubular cells without detectable renal dysfunction. Our findings may contribute to understanding the pathological effects of nephrotic syndrome on tubular cells.

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD), affecting over 40% of patients with diabetes. DKD progression involves fibrosis and damage to glomerular and tubulointerstitial regions, with mitochondrial dysfunction playing a critical role. Impaired mitochondria lead to reduced adenosine triphosphate (ATP) production, damaged mitochondria accumulation, and increased reactive oxygen species (ROS), contributing to renal deterioration. Maintaining mitochondrial quality control (MQC) is essential for preventing cell death, tissue injury, and kidney failure. Recent clinical trials show that enhancing MQC can alleviate DKD. However, current treatments cannot halt kidney function decline, underscoring the need for new therapeutic strategies. Mitochondrial-targeted drugs show potential; however, challenges remain because of adverse effects and unclear mechanisms. Future research should aim to comprehensively explore therapeutic potential of MQC in DKD. This review highlights the significance of MQC in DKD treatment, emphasizing the need to maintain mitochondrial quality for developing new therapies.

Kidney disease (KD) is a progressive and life-threatening illness that has manifested into a global health crisis, impacting >10% of the general population. Hallmarks of KD include tubular interstitial fibrosis, renal tubular cell atrophy/necrosis, glomerulosclerosis, persistent inflammation, microvascular endothelial cell (MV-EC) dysfunction/rarefaction, and mitochondrial dysfunction. Following acute kidney injury (AKI), and/or during KD onset/progression, MV-ECs of the renal peritubular endothelial capillaries (RPECs) are highly susceptible to injury, dysfunction, and rarefaction. Pharmacological induction of mitochondrial biogenesis (MB) via 5-hydroxytryptamine receptor 1F (HTR1F) agonism has been shown to enhance mitochondrial function and renal vascular recovery post-AKI in mice; however, little is known about MB in relation to renal MV-ECs and RPEC repair mechanisms. To address this gap in knowledge, the in vitro effects of the potent and selective FDA-approved HTR1F agonist lasmiditan were tested on primary mouse renal peritubular endothelial cells (MRPECs). Lasmiditan increased mitochondrial maximal respiration rates, mRNA and protein expression of MB-related genes, and mitochondrial number in MRPECs. MRPECs were then exposed to pro-inflammatory agents associated with renal MV-EC dysfunction, AKI, and KD (i.e., lipopolysaccharides, transforming growth factor-β1, and tumor necrosis factor-α), in the presence/absence of lasmiditan. Lasmiditan treatment augmented MRPEC wound healing, endothelial tubular network formation (ETNF), enhanced barrier integrity, and blunted inflammatory-induced MV-EC dysfunctions. Together, these data suggest that lasmiditan induces MB and improves wound healing and ETNF of primary MRPECs in the presence/absence of pro-inflammatory agents, highlighting a potential therapeutic role for lasmiditan treatment in renal MV-EC dysfunction, AKI, and/or KD.NEW & NOTEWORTHY Lasmiditan, an FDA-approved HTR1F agonist, induces mitochondrial biogenesis (MB) and enhances recovery following acute kidney injury in mice. Renal microvascular endothelial cells (MV-ECs) are highly susceptible to dysfunction/rarefaction postinjury. The effect of MB on MV-EC repair/recovery is unknown. We show that lasmiditan induces MB in primary mouse renal peritubular endothelial cells and improves wound healing, endothelial tubular network formation, and barrier integrity after inflammatory-induced dysfunction, indicative of its potential for the treatment of kidney diseases.

Renal proximal tubules are a primary site of injury in metabolic diseases. In obese patients and animal models, proximal tubular epithelial cells (PTECs) display dysregulated lipid metabolism, organelle dysfunctions, and oxidative stress that contribute to interstitial inflammation, fibrosis and ultimately end-stage renal failure. Our research group previously pointed out AMP-activated protein kinase (AMPK) decline as a driver of obesity-induced renal disease. Because PTECs display high macroautophagic/autophagic activity and rely heavily on their endo-lysosomal system, we investigated the effect of lipid stress on autophagic flux and lysosomes in these cells. Using a model of highly differentiated primary PTECs challenged with palmitate, our data placed lysosomes at the cornerstone of the lipotoxic phenotype. As soon as 6 h after palmitate exposure, cells displayed impaired lysosomal acidification subsequently leading to autophagosome accumulation and activation of lysosomal biogenesis. We also showed the inability of lysosomal quality control to restore acidic pH which finally drove PTECs dedifferentiation. When palmitate-induced AMPK activity decline was prevented by AMPK activators, lysosomal acidification and the differentiation profile of PTECs were preserved. Our work provided key insights on the importance of lysosomes in PTECs homeostasis and lipotoxicity and demonstrated the potential of AMPK in protecting the organelle from lipid stress.Abbreviation: ACAC: acetyl-CoA carboxylase; ACTB: actin beta; AICAR: 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside; AMPK: AMP-activated protein kinase; APQ1: aquaporin 1 (Colton blood group); BSA: bovine serum albumin; CDH16: cadherin 16; CKD: chronic kidney disease; CTSB: cathepsin B; CTSD: cathepsin D; EPB41L5: erythrocyte membrane protein band 4.1 like 5; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; EMT: epithelial-to-mesenchymal transition; FA: fatty acid; FCCP: carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone; GFP: green fluorescent protein; GUSB: glucuronidase beta; HEXB: hexosaminidase subunit beta; LAMP: lysosomal associated membrane protein; LD: lipid droplet; LGALS3: galectin 3; LLOMe: L-leucyl-L-leucine methyl ester hydrobromide; LMP: lysosomal membrane permeabilization; LRP2: LDL receptor related protein 2; LSD: lysosomal storage disorder; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MCOLN1: mucolipin TRP cation channel 1; MG132: N-benzyloxycarbonyl-L-leucyl-L-leucyl-L-leucinal; MmPTECs: Mus musculus (mouse) proximal tubular epithelial cells; MTORC1: mechanistic target of rapamycin kinase complex 1; OA: oleate; PA: palmitate; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PTs: proximal tubules; PTECs: proximal tubular epithelial cells; PRKAA: protein kinase AMP-activated catalytic subunit alpha; RFP: red fluorescent protein; RPS6KB: ribosomal protein S6 kinase B; SLC5A2: solute carrier family 5 member 2; SOX9: SRY-box transcription factor 9; SQSTM1: sequestosome 1; TFEB: transcription factor EB; Ub: ubiquitin; ULK1: unc-51 like autophagy activating kinase 1; VIM: vimentin.

Cryo-imaging has the potential to obtain and visualize the metabolic state of the whole kidney without labeling. However, uneven fixation of metabolic information and incomplete organ morphology in three dimensions limit cryo-imaging application. Here, a pipeline of in vivo insulated cryofixation combined with cryo-micro optical sectioning tomography (cryo-MOST) was established to achieve uniform and complete cryofixation and three-dimensional visualization of renal metabolic mapping at a micron-scale resolution. By this pipeline, we discovered an increased renal redox ratio of db/db mice with type 2 diabetes, indicating the presence of metabolic disorders. The results demonstrate that our convenient optical imaging tool provides a micro-resolution, quantitative assessment of the metabolic state of the whole kidney and potentially extends to other organs.

The kidney is one of the most metabolically demanding organs in the human body and requires a large amount of energy, in the form of adenosine triphosphate (ATP), to perform and maintain normal kidney functions. To meet this energy demand, proximal tubule cells within the nephron segments of the renal cortex are mitochondrially dense with high oxygen consumption rates. Mitochondria are complex organelles involved in diverse cellular and molecular functions, including the production of ATP, calcium homeostasis, and phospholipid regulation. Mitochondrial dysfunction is critical in the onset and progression of kidney disease. Dysfunctional renal mitochondria have been linked with alterations in redox homeostasis, impaired bioenergetics, oxidative stress, and inflammation, all of which result in renal cell injury and death, as well as fibrotic accumulation in kidney injury and disease. As such, interest in the development and/or repurposing of mitochondria-targeted therapeutics for the potential treatment of kidney diseases has recently surged. Although novel therapeutics and promising new drug targets have been identified, drug repurposing for kidney diseases offers numerous advantages over traditional drug discovery initiatives, including reduced cost, time of therapeutic development, and preclinical testing, in addition to known pharmacokinetics/pharmacodynamics and safety profiles. Here, we provide an overview of mitochondrial dysfunction in the context of kidney injury and disease and shed light on promising mitochondria-targeted therapeutic agents that display repurposing potential for the restoration of kidney function and/or acceleration of renal recovery.

Urolithiasis represents a systemic disorder characterized by metabolic circulation issues and ongoing inflammation. The purpose of this research is to explore the relationships of causation among plasma metabolites, biomarkers, inflammatory proteins, and stones within the urinary system. We initially carried out a two-sample Mendelian randomization (MR) analysis to evaluate possible causal connections between 233 plasma metabolites and 35 biomarkers related to urolithiasis. The genetic association study (GWAS) data concerning plasma metabolites were derived from a 2024 publication in Nature, while data for biomarkers were collected from the UK Biobank. To determine causal relationships, we utilized several analytical techniques, including inverse variance weighting (IVW), MR-Egger, weighted median, and weighted mode. Furthermore, we conducted analyses for pleiotropy and heterogeneity to ensure the findings' robustness. A Steiger analysis was used to explore the presence of any reverse causal relationships. Lastly, we conducted mediation analysis to elucidate how inflammatory proteins mediate the associations between plasma metabolites, biomarkers, and stones in the urinary system. Our research demonstrates causal connections between six plasma metabolites and six biomarkers related to upper urinary tract stones. Furthermore, we identified causal associations between ten plasma metabolites and four biomarkers linked to lower urinary tract stones. Most of these metabolites belong to lipid and lipoprotein classes, indicating that changes in blood lipid levels may influence stone formation. Finally, mediation analysis revealed 13 mediating relationships, including the mediating effects of six inflammatory proteins. Our results provide evidence for the causal links among plasma metabolites, biomarkers, and inflammatory proteins associated with urolithiasis. This provides new insights into the potential mechanisms underlying urinary system stone formation, contributing to their prevention, diagnosis, and treatment.

Acute kidney injury (AKI) remains a critical condition with limited therapeutic options, predominantly managed by renal replacement therapy. The challenge of developing targeted treatments persists.

We integrated genetic data related to druggable proteins and gene expression with AKI genome-wide association study (GWAS) findings. Based on multi-omics Mendelian randomization (MR), we identified the potential causal influence of 5,883 unique proteins and genes on AKI. We also performed using reverse MR and external cohort-based analysis to verify the robustness of this causal relationship. Expression patterns of these targets were examined using bulk transcriptome and single-cell transcriptome data. In addition, drug repurposing analyses were conducted to explore the potential of existing medications. We also constructed a molecular interaction network to explore the interplay between identified targets and known drugs.

Genetically predicted levels of seven proteins and twelve genes were associated with an increased risk of AKI. Of these, six targets (NCF1, TNFRSF1B, APEH, ACADSB, ADD1, and FAM3B) were prioritized based on robust evidence and validated in independent cohorts. Reverse MR showed a one-way causal relationship of targets. These targets are predominantly expressed in proximal tubular cells, endothelial cells, collecting duct-principal cells, and immune cells within both AKI-affected and normal tissues. Several promising drug repurposing opportunities were identified, such as telmisartan-NCF1, calcitriol-ACADSB, and ethinyl estradiol-ACADSB. The molecular interaction mapping and pathway integration analysis provided further insights, suggesting potential strategies for combinatorial therapies.

This extensive investigation identified several promising therapeutic targets for AKI and highlighted opportunities for drug repurposing. These findings offer valuable insights that could shape future research and the development of targeted treatments.

Due to their role in excretion, renal proximal tubular cells are susceptible to damage by toxic metabolites and xenobiotics. The regenerative capacity of the kidney allows for the replacement of damaged cells, a process involving differentiation programs. However, kidney function tends to decline, suggesting that the replacement cells may not achieve full functionality. To understand possible causes of this decline, we investigated effects of nephrotoxins and oxidants on the differentiation of induced pluripotent stem cells (iPSC) into proximal tubular epithelial-like cells (PTELC). Proliferation, apoptosis, senescence, and expression of oxidative defense genes were analyzed in iPSC, differentiating and differentiated cells treated with cisplatin (CisPt, up to 45 µM), cyclosporin A (CycA, up to 12 µM), and the oxidants menadione (Mena, up to 50 µM) and tert-butylhydroquinone (tBHQ, up to 50 µM). We found that differentiating cells were most sensitive to oxidants and showed increased sensitivity to CisPt, whereas all differentiation stages showed similar sensitivity to CycA. Both oxidative stress and CisPt triggered apoptosis in all differentiation stages, whereas CycA mainly induced senescence. Treatment during differentiation resulted in long-term effects on gene expression in differentiated cells. While oxidants had no effect on transport function of differentiated cells, CisPt and CycA impaired albumin uptake. Our data suggest a substantial sensitivity of differentiating cells to nephrotoxins and oxidants, an aspect that could potentially interfere with regenerative processes.

Acute kidney injury (AKI) encompasses pathophysiology ranging from glomerular hypofiltration to tubular cell injury and outflow obstruction. This Review will focus on the tubulointerstitial processes that underlie most cases of AKI. Tubular epithelial cell (TEC) injury can occur via distinct insults, including ischemia, nephrotoxins, sepsis, and primary immune-mediated processes. Following these initial insults, tubular cells can activate survival and repair responses or they can develop mitochondrial dysfunction and metabolic reprogramming, cell-cycle arrest, and programmed cell death. Developing evidence suggests that the fate of individual tubular cells to survive and proliferate or undergo cell death or senescence is frequently determined by a biphasic immune response with initial proinflammatory macrophage, neutrophil, and lymphocyte infiltration exacerbating injury and activating programmed cell death, while alternatively activated macrophages and specific lymphocyte subsets subsequently modulate inflammation and promote repair. Functional recovery requires that this reparative phase supports proteolytic degradation of tubular casts, proliferation of surviving TECs, and restoration of TEC differentiation. Incomplete resolution or persistence of inflammation can lead to failed tubular repair, fibrosis, and chronic kidney disease. Despite extensive research in animal models, translating preclinical findings to therapies remains challenging, emphasizing the need for integrated multiomic approaches to advance AKI understanding and treatment.

Protein S-nitrosylation (SNO), a redox-based posttranslational modification of cysteine thiols, plays a crucial role in various signaling pathways. Peroxiredoxin 2 (PRDX2) is one of the most potent ROS scavenging proteins, providing protection against oxidative stress damage, with its function regulated by SNO. However, the precise role of SNO-PRDX2 in hyperuricemic nephropathy remains poorly understood. In this study, we identified PRDX2 as a highly S-nitrosylated target in hyperuricemic nephropathy using a biotin switch assay. The elevation of SNO-PRDX2 was observed in kidneys of hyperuricemic mice as well as in uric acid (UA)-treated human renal tubular epithelial (HK-2) cells. S-nitrosoglutathione (GSNO), an endogenous nitric oxide carrier, induced SNO modification of PRDX2, promoting mitochondrial dysfunction, oxidative stress, and cell apoptosis in HK-2 cells. Transfection with a plasmid containing a mutated cysteine 172 (Cys172) of PRDX2 yielded a decrease in SNO-PRDX2 levels in both hyperuricemic mice and UA-cultured HK-2 cells. Furthermore, administration of adeno-associated viruses carrying the Cys172-mutated PRDX2 significantly ameliorated renal interstitial fibrosis and reduced mitochondrial dysfunction, oxidative stress, and cell apoptosis in HUA-treated mice. In conclusion, our findings indicate that SNO modification of PRDX2 at Cys172 mediates HUA-induced kidney interstitial fibrosis, suggesting that SNO-PRDX2 may serve as a potential therapeutic target for HUA-induced renal injury.