Targeting the Wnt/β-Catenin Signaling Pathway as a Potential Therapeutic Strategy in Renal Tubulointerstitial Fibrosis

A PDE1 inhibitor, vinpocetine, ameliorates epithelial-mesenchymal transition and renal fibrosis in adenine-induced chronic kidney injury in rats by targeting the DNMT1/Klotho/β-catenin/Snail 1 and MMP-7 pathways

Tubulointerstitial fibrosis (TIF) is present with chronic kidney disease (CKD). Vinpocetine (Vinpo) is used for treating cerebrovascular deficits, exhibiting some kidney-beneficial effects; however, its role in TIF is uncertain. So, the aim of this study was to investigate its potential impact on adenine-induced fibrotic CKD and explore the underlying mechanistic aspects. Eighteen male Wistar rats were categorized into three groups (n = 6 each). Group I was kept as controls and given saline; group II received adenine (300 mg/kg, twice weekly, i.p.) for induction of the CKD model; and group III was administered Vinpo (20 mg/kg/d, orally) concurrently with adenine. All treatments were administered for 4 weeks. Vinpo revealed an improvement in renal function and an alleviation of inflammation triggered by adenine via diminishing serum tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) levels. Further, Vinpo repressed the epithelial-mesenchymal transition (EMT) with preserved E-cadherin mRNA expression and lowered gene and immune expression of fibronectin and vimentin, respectively, besides attenuating the elevated G2/M arrest-related molecules (renal Ki67 protein contents and p21 gene expression). Renal pathological alterations caused by adenine were attenuated upon Vinpo administration. Interestingly, Vinpo suppressed abnormal renal β-catenin immunoreactivity, Snail 1, and MMP-7 gene expression while simultaneously restored Klotho protein expression by downregulating DNA methyltransferase 1 enzyme (DNMT1) protein expression in the kidney. These data indicated that Vinpo effectively mitigated EMT and G2/M arrest-induced renal fibrosis in adenine-induced CKD rats by targeting DNMT1-associated Klotho suppression, subsequently inhibiting β-catenin and its fibrotic downstream genes.

Renal Implications of Dysregulated Protein Homeostasis: Insights into Ubiquitin-Proteasome and Autophagy Systems

The ubiquitin-proteasome system (UPS) and autophagy maintain protein homeostasis, which is critical to cellular function and survival. The dysregulation of these pathways has been recognized as a hallmark of acute kidney injury and chronic kidney disease. This review elucidates the role of the UPS and autophagy in kidney disease, namely through inflammation, oxidative stress, fibrosis and apoptosis. The pathways of NF-κB, TGF-β and mitochondrial failure result in glomerular injury and tubulointerstitial fibrosis due to impaired proteostasis in podocytes and tubular epithelial cells. Recent studies have revealed a connection between the autophagic process and the UPS, wherein compensatory mechanisms aim to spike down proteotoxic stress but eventually seem inadequate in cases of chronic derangement. Low-dose pharmacological inhibitors, autophagy modulators, and new gene and nanotechnology-based treatments may all help to restore the protein balance and reduce kidney injury. A more thorough understanding of these pathways is needed to develop kidney-protective and disease-modifying therapeutic interventions.

Interrelation of Natural Polyphenol and Fibrosis in Diabetic Nephropathy

Diabetic nephropathy (DN) is a common and serious complication of diabetes mellitus and a major cause of end-stage renal disease (ESRD). Renal fibrosis, which corresponds to excessive deposition of extracellular matrix and leads to scarring, is a characteristic feature of the various progressive stages of DN. It can trigger various pathological processes leading to the activation of autophagy, inflammatory responses and a vicious circle of oxidative stress and inflammation. Although it is known that DN can be alleviated by mechanisms linked to antioxidants, reducing inflammation and improving autophagy, how to improve DN by reducing fibrosis using natural polyphenols needs to be studied further. Nowadays, natural polyphenolic compounds with excellent safety and efficacy are playing an increasingly important role in drug discovery. Therefore, this review reveals the multiple mechanisms associated with fibrosis in DN, as well as the different signaling pathways (including TGF-β/SMAD, mTORC1/p70S6K, JAK/STAT/SOCS and Wnt/β-catenin) and the potential role in the fibrotic niche. In parallel, we summarize the types of polyphenolic compounds and their pharmacodynamic effects, and finally evaluate the use of polyphenols to modulate relevant targets and pathways, providing potential research directions for polyphenols to improve DN. In summary, the problem of long-term monotherapy resistance can be reduced with natural polyphenols, while reducing the incidence of toxic side effects. In addition, potential targets and their inhibitors can be identified through these pathways, offering potential avenues of research for natural polyphenols in the pharmacological treatment of multisite fibrosis.

Personalized Antifibrotic Therapy in CKD Progression

Chronic kidney disease (CKD) is a chronic disorder characterized by kidney fibrosis and extracellular matrix accumulation that can lead to end-stage kidney disease. Epithelial-to-mesenchymal transition, inflammatory cytokines, the TGF-β pathway, Wnt/β-catenin signaling, the Notch pathway, and the NF-κB pathway all play crucial roles in the progression of fibrosis. Current medications, such as renin-angiotensin-aldosterone system inhibitors, try to delay disease development but do not stop or reverse fibrosis. This review emphasizes the growing need for tailored antifibrotic medications for CKD treatment. Precision medicine, which combines proteomic, metabolomic, and genetic data, provides a practical way to personalize treatment regimens. Proteomic signatures, such as CKD273, and genetic markers, such as APOL1 and COL4A5, help in patient stratification and focused therapy development. Two recently developed antifibrotic medications, nintedanib and pirfenidone, have been proven to diminish fibrosis in preclinical animals. Additionally, research is being conducted on the efficacy of investigational drugs targeting CTGF and galectin-3 in the treatment of kidney fibrosis.

Therapeutic effect of total glucosides of paeony on IgA vasculitis nephritis: progress and prospects

IgA vasculitis nephritis (IgAVN), a type of immune system disease characterized by the deposition of IgA in the mesangial area of the glomerulus, is most common in children. Corticosteroids and immunosuppressants agents are commonly prescribed for the clinical management of IgAVN; however, these therapies are associated with numerous adverse reactions. This necessitates the discovery of alternative, potential therapeutic agents that can offer a safer treatment option. Natural plants contain abundant total glucosides of paeony (TGP), which represent one of the most prevalent secondary metabolites found within these organisms. TGP has been proven to be a safe and desirable natural medicine, with the most central ingredient being polyphenolic. TGP, a naturally occurring and cost-effective compound, exerts its therapeutic influence on IgAVN via diverse pathways and targets, with minimal side effects. Its substantial clinical potential underscores the importance of delving deeper into its pharmacological mechanisms, which hold great promise for novel drug development. This review examines the multifaceted therapeutic mechanisms of TGP in IgAVN encompassing modulation of Wnt/β-catenin pathways and programmed cell death pathways, antioxidant and anti-inflammatory effects, and enhancement of vascular repair. Additionally, we provide an overview of recent advancements in enhancing the bioavailability of TGP and highlight crucial considerations that may inform future research endeavors.

Identification of Genes Associated with Familial Focal Segmental Glomerulosclerosis Through Transcriptomics and In Silico Analysis, Including RPL27, TUBB6, and PFDN5

Focal segmental glomerulosclerosis (FSGS) is a major cause of nephrotic syndrome and often leads to progressive kidney failure. Its varying clinical presentation suggests potential genetic diversity, requiring further molecular investigation. This study aims to elucidate some of the genetic and molecular mechanisms underlying FSGS. The study focuses on the use of bioinformatic analysis of gene expression data to identify genes associated with familial FSGS. A comprehensive in silico analysis was performed using the GSE99340 data set from Gene Expression Omnibus (GEO) comparing gene expression in glomerular and tubulointerstitial tissues from FSGS patients (n = 10) and Minimal Change Disease (MCD) patients (n = 8). These findings were validated using transcriptomics data obtained using RNA sequencing from FSGS (n = 3) and control samples (n = 3) from the UAE. Further validation was conducted using qRT-PCR on an independent FFPE cohort (FSGS, n = 6; MCD, n = 7) and saliva samples (FSGS, n = 3; Control, n = 7) from the UAE. Three genes (TUBB6, RPL27, and PFDN5) showed significant differential expression (p < 0.01) when comparing FSGS and MCD with healthy controls. These genes are associated with cell junction organization and synaptic pathways of the neuron, supporting the link between FSGS and the neural system. These genes can potentially be useful as diagnostic biomarkers for FSGS and to develop new treatment options.

Klotho: molecular mechanisms and emerging therapeutics in central nervous system diseases

Klotho is recognized as an aging-suppressor protein that is implicated in a variety of processes and signaling pathways. The anti-inflammatory, anti-apoptotic, anti-oxidant, and anti-tumor bioactivities of klotho have extended its application in neurosciences and made the protein popular for its lifespan-extending capacity. Furthermore, it has been demonstrated that klotho levels would reduce with aging and numerous pathologies, particularly those related to the central nervous system (CNS). Evidence supports the idea that klotho can be a key therapeutic target in CNS diseases such as amyotrophic lateral sclerosis, Parkinson's disease, stroke, and Alzheimer's disease. Reviewing the literature suggests that the upregulation of klotho expression regulates various signaling pathways related to autophagy, oxidative stress, inflammation, cognition, and ferroptosis in neurological disorders. Therefore, it has been of great interest to develop drugs or agents that boost or restore klotho levels. In this regard, the present review was designed and aimed to gather the delegated documents regarding the therapeutic potential of Klotho in CNS diseases focusing on the molecular and cellular mechanisms.

Traditional Chinese medicine in osteoporosis: from pathogenesis to potential activity

Osteoporosis characterized by decreased bone density and mass, is a systemic bone disease with the destruction of microstructure and increase in fragility. Osteoporosis is attributed to multiple causes, including aging, inflammation, diabetes mellitus, and other factors induced by the adverse effects of medications. Without treatment, osteoporosis will further progress and bring great trouble to human life. Due to the various causes, the treatment of osteoporosis is mainly aimed at improving bone metabolism, inhibiting bone resorption, and promoting bone formation. Although the currently approved drugs can reduce the risk of fragility fractures in individuals, a single drug has limitations in terms of safety and effectiveness. By contrast, traditional Chinese medicine (TCM), a characteristic discipline in China, including syndrome differentiation, Chinese medicine prescription, and active ingredients, shows unique advantages in the treatment of osteoporosis and has received attention all over the world. Therefore, this review summarized the pathogenic factors, pathogenesis, therapy limitations, and advantages of TCM, aiming at providing new ideas for the prevention and treatment of OP.

Secreted frizzled-related protein 5 protects against renal fibrosis by inhibiting Wnt/β-catenin pathway

Renal fibrosis (RF) is an important pathogenesis for renal function deterioration in chronic kidney disease. Secreted frizzled-related protein 5 (SFRP5) is an anti-fibrotic adipokine but its direct role on RF remains unknown. It was aimed to study the protective effect of SFRP5 against RF and interference with Wnt/β-catenin signaling pathway for the first time. First, the therapeutic efficacy of SFRP5 was evaluated by adenovirus overexpression in rats with unilateral ureteral obstruction (UUO) in vivo. Thirty-six rats were randomly divided into the sham, UUO, and SFRP5 (UUO + Ad-SFRP5) groups. Half rats in each group were selected at random for euthanasia at 7 days and the others until 14 days. Then, the transforming growth factor (TGF)-β1-induced epithelial-mesenchymal transition (EMT) was established in HK-2 cells in vitro. The cells were divided into four groups: the control group, the TGF-β1 group, the TGF-β1 + SFRP5 group, and the TGF-β1 + SFRP5 + anti-SFRP5 group. The makers of EMT and Wnt/β-catenin pathway proteins were investigated. In the UUO model, expression of SFRP5 showed compensatory upregulation, and adenoviral-mediated SFRP5 over-expression remarkably attenuated RF, as demonstrated by maintenance of E-cadherin and suppression of α-smooth muscle actin (SMA). In vitro, SFRP5 was shown to inhibit TGF-β1-mediated positive regulation of α-SMA, fibronectin, collagen I but negative regulation of E-cadherin. Furthermore, SFRP5 abrogated activation of Wnt/β-catenin, which was the essential pathway in EMT and RF pathogenesis. The changes after a neutralizing antibody to SFRP5 confirmed the specificity of SFRP5 for inhibition. These findings suggest that SFRP5 can directly ameliorate EMT and protect against RF by inhibiting Wnt/β-catenin pathway.

Protective effect of chicory and/or artichoke leaves extracts on carbon tetrachloride and gamma-irradiation-induced chronic nephrotoxicity in rats

The prevalence of chronic kidney disease (CKD) is in progress that causes kidney failure, leading to global problems. This manuscript investigated the nephroprotective effects of chicory (CLE) and/or artichoke (ALE) leaves extracts on carbon tetrachloride (CCl4 ) and gamma-irradiation (Rad)-induced chronic nephrotoxicity in rats. Rats were divided into 10 groups (10 animals/group): group 1: control, groups 2-7 rats were treated with CLE, ALE, CLE/ALE, CCl4 , Rad, and CCl4 /Rad, respectively. Groups 8 to 10, rats were intoxicated with CCl4 /Rad, and treated with CLE, ALE, and CLE/ALE extracts, respectively, for 4 weeks. The data demonstrated that CCl4 administration or Rad exposure induced high levels of urea and creatinine, with low levels of total protein and albumin in the serum. However, high levels of malondialdehyde (MDA), nitric oxide (NO), hydrogen peroxide (H2 O2 ), some pro-inflammatory markers such as interleukins (IL-1β, IL-2, IL-6), TNF-α, NF-κB, the fibrotic marker; TGF-β1, calcium, and copper, low contents of reduced glutathione (GSH), iron, and zinc, and suppression of the antioxidant enzymes' activity, superoxide dismutase (SOD), and catalase (CAT) were observed. In addition, the Wnt and β-catenin protein expression ratios were up-regulated in the kidney tissues of the CCl4 , and Rad intoxicated animals. However, the combined treatment CCl4 /Rad augmented these measurements. On the other hand, CLE, ALE, and CLE/ALE treatments demonstrated nephroprotection in the kidney tissues of CCl4 /Rad intoxicated animals, in the order of CLE/ALE>ALE>CLE by ameliorating the investigated parameters. Kidney tissues' histopathological examinations confirmed these results. In conclusion, CLE and/or ALE demonstrated nephroprotection against CCl4 /Rad co-toxicity mediated by down-regulation of renal Wnt/β-catenin protein expressions.

Macrophage Ontogeny, Phenotype, and Function in Ischemia Reperfusion-Induced Injury and Repair

AKI is characterized by a sudden, and usually reversible, decline in kidney function. In mice, ischemia-reperfusion injury (IRI) is commonly used to model the pathophysiologic features of clinical AKI. Macrophages are a unifying feature of IRI as they regulate both the initial injury response as well as the long-term outcome following resolution of injury. Initially, macrophages in the kidney take on a proinflammatory phenotype characterized by the production of inflammatory cytokines, such as CCL2 (monocyte chemoattractant protein 1), IL-6, IL-1 β , and TNF- α . Release of these proinflammatory cytokines leads to tissue damage. After resolution of the initial injury, macrophages take on a reparative role, aiding in tissue repair and restoration of kidney function. By contrast, failure to resolve the initial injury results in prolonged inflammatory macrophage accumulation and increased kidney damage, fibrosis, and the eventual development of CKD. Despite the extensive amount of literature that has ascribed these functions to M1/M2 macrophages, a recent paradigm shift in the macrophage field now defines macrophages on the basis of their ontological origin, namely monocyte-derived and tissue-resident macrophages. In this review, we focus on macrophage phenotype and function during IRI-induced injury, repair, and transition to CKD using both the classic (M1/M2) and novel (ontological origin) definition of kidney macrophages.

GPR97 deficiency suppresses Wnt/β-catenin signaling in hypertensive nephropathy

Accumulating evidence shows that renal fibrosis plays a key role in the development of hypertensive nephropathy (HTN). Therefore, a better understanding of the underlying mechanism of renal fibrosis regulation in HTN would be critical for designing rational strategies for therapeutic interventions. In this study, we revealed that GPR97, a novel identified adhesion G coupled receptor, plays an important role in the regulation of Wnt/β-catenin signaling, which is the crucial driver of renal fibrosis in HTN. First, we identified that the expression of GPR97 correlated with the β-catenin expression in renal biopsy from patients with HTN. Moreover, we found that GPR97 deficiency inhibited Wnt/β-catenin signaling in mice with HTN, as evidenced by the reduction of β-catenin expression and downstream target proteins, including MMP7 and Fibronectin. Mechanistically, we found that GPR97 could directly bind with Wnt1 in cultured tubular cells and TGF-β1 treatment enhanced the binding ability of GPR97 and Wnt1. In addition, the gene silencing of GPR97 could decrease the Wnt1-induced fibrotic phenotype of tubular cells and inflammatory responses, suggesting that the binding of GPR97 and Wnt1 promoted Wnt/β-catenin signaling. Collectively, our studies reveal that GPR97 is a regulator of Wnt/β-catenin signaling in HTN, and targeting GPR97 may be a novel therapeutic strategy for HTN treatment.

Comparative Analysis of Acute Kidney Injury Models and Related Fibrogenic Responses: Convergence on Methylation Patterns Regulated by Cold Shock Protein

BACKGROUND

Fibrosis is characterized by excessive extracellular matrix formation in solid organs, disrupting tissue architecture and function. The Y-box binding protein-1 (YB-1) regulates fibrosis-related genes (e.g., Col1a1, Mmp2, and Tgfβ1) and contributes significantly to disease progression. This study aims to identify fibrogenic signatures and the underlying signaling pathways modulated by YB-1.

METHODS

Transcriptomic changes associated with matrix gene patterns in human chronic kidney diseases and murine acute injury models were analyzed with a focus on known YB-1 targets. Ybx1-knockout mouse strains (Ybx1ΔRosaERT+TX and Ybx1ΔLysM) were subjected to various kidney injury models. Fibrosis patterns were characterized by histopathological staining, transcriptome analysis, qRT-PCR, methylation analysis, zymography, and Western blotting.

RESULTS

Integrative transcriptomic analyses revealed that YB-1 is involved in several fibrogenic signatures related to the matrisome, the WNT, YAP/TAZ, and TGFß pathways, and regulates Klotho expression. Changes in the methylation status of the Klotho promoter by specific methyltransferases (DNMT) are linked to YB-1 expression, extending to other fibrogenic genes. Notably, kidney-resident cells play a significant role in YB-1-modulated fibrogenic signaling, whereas infiltrating myeloid immune cells have a minimal impact.

CONCLUSIONS

YB-1 emerges as a master regulator of fibrogenesis, guiding DNMT1 to fibrosis-related genes. This highlights YB-1 as a potential target for epigenetic therapies interfering in this process.

Comprehensive strategy for identifying extracellular vesicle surface proteins as biomarkers for chronic kidney disease

Chronic kidney disease (CKD) poses a significant health burden worldwide. Especially, obesity-induced chronic kidney disease (OCKD) is associated with a lack of accuracy in disease diagnostic methods. The identification of reliable biomarkers for the early diagnosis and monitoring of CKD and OCKD is crucial for improving patient outcomes. Extracellular vesicles (EVs) have emerged as potential biomarkers in the context of CKD. In this review, we focused on the role of EVs as potential biomarkers in CKD and OCKD and developed a comprehensive list of EV membrane proteins that could aid in the diagnosis and monitoring of the disease. To assemble our list, we employed a multi-step strategy. Initially, we conducted a thorough review of the literature on EV protein biomarkers in kidney diseases. Additionally, we explored papers investigating circulating proteins as biomarkers in kidney diseases. To further refine our list, we utilized the EV database Vesiclepedia.org to evaluate the qualifications of each identified protein. Furthermore, we consulted the Human Protein Atlas to assess the localization of these candidates, with a particular focus on membrane proteins. By integrating the information from the reviewed literature, Vesiclepedia.org, and the Human Protein Atlas, we compiled a comprehensive list of potential EV membrane protein biomarkers for CKD and OCKD. Overall, our review underscores the potential of EVs as biomarkers in the field of CKD research, providing a foundation for future studies aimed at improving CKD and OCKD diagnosis and treatment.

From Acute to Chronic: Unraveling the Pathophysiological Mechanisms of the Progression from Acute Kidney Injury to Acute Kidney Disease to Chronic Kidney Disease

This article provides a thorough overview of the biomarkers, pathophysiology, and molecular pathways involved in the transition from acute kidney injury (AKI) and acute kidney disease (AKD) to chronic kidney disease (CKD). It categorizes the biomarkers of AKI into stress, damage, and functional markers, highlighting their importance in early detection, prognosis, and clinical applications. This review also highlights the links between renal injury and the pathophysiological mechanisms underlying AKI and AKD, including renal hypoperfusion, sepsis, nephrotoxicity, and immune responses. In addition, various molecules play pivotal roles in inflammation and hypoxia, triggering maladaptive repair, mitochondrial dysfunction, immune system reactions, and the cellular senescence of renal cells. Key signaling pathways, such as Wnt/β-catenin, TGF-β/SMAD, and Hippo/YAP/TAZ, promote fibrosis and impact renal function. The renin-angiotensin-aldosterone system (RAAS) triggers a cascade leading to renal fibrosis, with aldosterone exacerbating the oxidative stress and cellular changes that promote fibrosis. The clinical evidence suggests that RAS inhibitors may protect against CKD progression, especially post-AKI, though more extensive trials are needed to confirm their full impact.

The nuclear factor kappa B signaling pathway is a master regulator of renal fibrosis

Renal fibrosis is increasingly recognized as a global public health problem. Acute kidney injury (AKI) and chronic kidney disease (CKD) both result in renal fibrosis. Oxidative stress and inflammation play central roles in progressive renal fibrosis. Oxidative stress and inflammation are closely linked and form a vicious cycle in which oxidative stress induces inflammation through various molecular mechanisms. Ample evidence has indicated that a hyperactive nuclear factor kappa B (NF-ƙB) signaling pathway plays a pivotal role in renal fibrosis. Hyperactive NF-ƙB causes the activation and recruitment of immune cells. Inflammation, in turn, triggers oxidative stress through the production of reactive oxygen species and nitrogen species by activating leukocytes and resident cells. These events mediate organ injury through apoptosis, necrosis, and fibrosis. Therefore, developing a strategy to target the NF-ƙB signaling pathway is important for the effective treatment of renal fibrosis. This Review summarizes the effect of the NF-ƙB signaling pathway on renal fibrosis in the context of AKI and CKD (immunoglobulin A nephropathy, membranous nephropathy, diabetic nephropathy, hypertensive nephropathy, and kidney transplantation). Therapies targeting the NF-ƙB signaling pathway, including natural products, are also discussed. In addition, NF-ƙB-dependent non-coding RNAs are involved in renal inflammation and fibrosis and are crucial targets in the development of effective treatments for kidney disease. This Review provides a clear pathophysiological rationale and specific concept-driven therapeutic strategy for the treatment of renal fibrosis by targeting the NF-ƙB signaling pathway.

Sirtuin 6 protects against podocyte injury by blocking the renin-angiotensin system by inhibiting the Wnt1/β-catenin pathway

Sirtuins (Sirts) are a family of nicotinamide adenine dinucleotide-dependent protein deacetylases that share diverse cellular functions. Increasing evidence shows that Sirts play a critical role in podocyte injury, which is a major determinant of proteinuria-associated renal disease. Membranous nephropathy (MN) is a typical glomerular disease in which podocyte damage mediates proteinuria development. In this study we investigated the molecular mechanisms underlying the regulatory roles of Sirt in podocyte injury in MN patients, rats with cationic bovine serum albumin (CBSA)-induced MN and zymosan activation serum (ZAS)-stimulated podocytes. Compared with healthy controls, MN patients showed significant reduction in intrarenal Sirt1 and Sirt6 protein expression. In CBSA-induced MN rats, significant reduction in intrarenal Sirt1, Sirt3 and Sirt6 protein expression was observed. However, only significant decrease in Sirt6 protein expression was found in ZAS-stimulated podocytes. MN patients showed significantly upregulated protein expression of Wnt1 and β-catenin and renin-angiotensin system (RAS) components in glomeruli. CBSA-induced MN rats exhibited significantly upregulated protein expression of intrarenal Wnt1 and β-catenin and their downstream gene products as well as RAS components. Similar results were observed in ZAS-stimulated podocytes. In ZAS-stimulated podocytes, treatment with a specific Sirt6 activator UBCS039 preserved the protein expression of podocin, nephrin and podocalyxin, accompanied by significant inhibition of the protein expression of β-catenin and its downstream gene products, including Snail1 and Twist; treatment with a β-catenin inhibitor ICG-001 significantly preserved the expression of podocyte-specific proteins and inhibited the upregulation of downstream β-catenin gene products accompanied by significant suppression of the protein expression of RAS components. Thus, we demonstrate that Sirt6 ameliorates podocyte injury by blocking RAS signalling via the Wnt1/β-catenin pathway. Sirt6 is a specific therapeutic target for the treatment of podocyte damage-associated renal disease.

The possible role of Wnt/β-catenin signalling in vitiligo treatment

Vitiligo is a common chronic skin disease which has an adverse impact on patients' life. Its pathogenesis is complex, involving autoimmunity and oxidative stress (OS). Autoimmunity leads to the loss of epidermal melanocytes and the formation of the depigmented patches of the disease. Treatment of vitiligo should control the exaggerated immune response to arrest the progress of active disease, and then promote melanocytes to repigmentation. Wnt/β-catenin signalling pathway has been of recent interest in vitiligo. Wnt/β-catenin signalling pathway is downregulated in vitiligo. Upregulation of Wnt/β-catenin signalling possibly control vitiligo autoimmune response by protecting melanocyte from OS damage, inhibiting CD8+ T cell effector cell differentiation and enhancing Treg. Wnt/β-catenin signalling plays a critical role in the melanocyte regeneration by driving the differentiation of melanocyte stem cells (McSCs) into melanocytes. Promoting Wnt/β-catenin signalling can not only arrest the progress of active disease of vitiligo but also promote repigmentation. Some of the main effective therapies for vitiligo are likely to work by activating Wnt/β-catenin signalling. Agents that can enhance the effect of Wnt/β-catenin signalling may become potential candidates for the development of new drugs for vitiligo treatment.

Novel Approaches in Chronic Renal Failure without Renal Replacement Therapy: A Review

Chronic kidney disease (CKD) is characterized by renal parenchymal damage leading to a reduction in the glomerular filtration rate. The inflammatory response plays a pivotal role in the tissue damage contributing to renal failure. Current therapeutic options encompass dietary control, mineral salt regulation, and management of blood pressure, blood glucose, and fatty acid levels. However, they do not effectively halt the progression of renal damage. This review critically examines novel therapeutic avenues aimed at ameliorating inflammation, mitigating extracellular matrix accumulation, and fostering renal tissue regeneration in the context of CKD. Understanding the mechanisms sustaining a proinflammatory and profibrotic state may offer the potential for targeted pharmacological interventions. This, in turn, could pave the way for combination therapies capable of reversing renal damage in CKD. The non-replacement phase of CKD currently faces a dearth of efficacious therapeutic options. Future directions encompass exploring vaptans as diuretics to inhibit water absorption, investigating antifibrotic agents, antioxidants, and exploring regenerative treatment modalities, such as stem cell therapy and novel probiotics. Moreover, this review identifies pharmaceutical agents capable of mitigating renal parenchymal damage attributed to CKD, targeting molecular-level signaling pathways (TGF-β, Smad, and Nrf2) that predominate in the inflammatory processes of renal fibrogenic cells.

TGF-β as A Master Regulator of Aging-Associated Tissue Fibrosis

Fibrosis is the abnormal accumulation of extracellular matrix proteins such as collagen and fibronectin. Aging, injury, infections, and inflammation can cause different types of tissue fibrosis. Numerous clinical investigations have shown a correlation between the degree of liver and pulmonary fibrosis in patients and telomere length and mitochondrial DNA content, both of which are signs of aging. Aging involves the gradual loss of tissue function over time, which results in the loss of homeostasis and, ultimately, an organism's fitness. A major feature of aging is the accumulation of senescent cells. Senescent cells abnormally and continuously accumulate in the late stages of life, contributing to age-related fibrosis and tissue deterioration, among other aging characteristics. Furthermore, aging generates chronic inflammation, which results in fibrosis and decreases organ function. This finding suggests that fibrosis and aging are closely related. The transforming growth factor-beta (TGF-β) superfamily plays a crucial role in the physiological and pathological processes of aging, immune regulation, atherosclerosis, and tissue fibrosis. In this review, the functions of TGF-β in normal organs, aging, and fibrotic tissues is discussed: TGF-β signalling is altered with age and is an indicator of pathology associated with tissue fibrosis. In addition, this review discusses the potential targeting of noncoding.

Endothelial Dysfunction in Cardiorenal Conditions: Implications of Endothelial Glucocorticoid Receptor-Wnt Signaling

The endothelium constitutes the innermost lining of the blood vessels and controls blood fluidity, vessel permeability, platelet aggregation, and vascular tone. Endothelial dysfunction plays a key role in initiating a vascular inflammatory cascade and is the pivotal cause of various devastating diseases in multiple organs including the heart, lung, kidney, and brain. Glucocorticoids have traditionally been used to combat vascular inflammation. Endothelial cells express glucocorticoid receptors (GRs), and recent studies have demonstrated that endothelial GR negatively regulates vascular inflammation in different pathological conditions such as sepsis, diabetes, and atherosclerosis. Mechanistically, the anti-inflammatory effects of GR are mediated, in part, through the suppression of Wnt signaling. Moreover, GR modulates the fatty acid oxidation (FAO) pathway in endothelial cells and hence can influence FAO-mediated fibrosis in several organs including the kidneys. This review summarizes the relationship between GR and Wnt signaling in endothelial cells and the effects of the Wnt pathway in different cardiac and renal diseases. Available data suggest that GR plays a significant role in restoring endothelial integrity, and research on endothelial GR-Wnt interactions could facilitate the development of novel therapies for many cardiorenal conditions.

Hexarelin alleviates apoptosis on ischemic acute kidney injury via MDM2/p53 pathway

INTRODUCTION

Hexarelin exhibits significant protection against organ injury in models of ischemia/reperfusion (I/R)-induced injury (IRI). Nevertheless, the impact of Hexarelin on acute kidney injury (AKI) and its underlying mechanism remains unclear. In this study, we investigated the therapeutic potential of Hexarelin in I/R-induced AKI and elucidated its molecular mechanisms.

METHODS

We assessed the protective effects of Hexarelin through both in vivo and in vitro experiments. In the I/R-induced AKI model, rats were pretreated with Hexarelin at 100 μg/kg/d for 7 days before being sacrificed 24 h post-IRI. Subsequently, kidney function, histology, and apoptosis were assessed. In vitro, hypoxia/reoxygenation (H/R)-induced HK-2 cell model was used to investigate the impact of Hexarelin on apoptosis in HK-2 cells. Then, we employed molecular docking using a pharmmapper server and autodock software to identify potential target proteins of Hexarelin.

RESULTS

In this study, rats subjected to I/R developed severe kidney injury characterized by tubular necrosis, tubular dilatation, increased serum creatinine levels, and cell apoptosis. However, pretreatment with Hexarelin exhibited a protective effect by mitigating post-ischemic kidney pathological changes, improving renal function, and inhibiting apoptosis. This was achieved through the downregulation of conventional apoptosis-related genes, such as Caspase-3, Bax and Bad, and the upregulation of the anti-apoptotic protein Bcl-2. Consistent with the in vivo results, Hexarelin also reduced cell apoptosis in post-H/R HK-2 cells. Furthermore, our analysis using GSEA confirmed the essential role of the apoptosis pathway in I/R-induced AKI. Molecular docking revealed a strong binding affinity between Hexarelin and MDM2, suggesting the potential mechanism of Hexarelin's anti-apoptosis effect at least partially through its interaction with MDM2, a well-known negative regulator of apoptosis-related protein that of p53. To validate these findings, we evaluated the relative expression of MDM2 and p53 in I/R-induced AKI with or without Hexarelin pre-administration and observed a significant suppression of MDM2 and p53 by Hexarelin in both in vivo and in vitro experiments.

CONCLUSION

Collectively, Hexarelin was identified as a promising medication in protecting apoptosis against I/R-induced AKI.

Pathway from Acute Kidney Injury to Chronic Kidney Disease: Molecules Involved in Renal Fibrosis

Acute kidney injury (AKI) is one of the main conditions responsible for chronic kidney disease (CKD), including end-stage renal disease (ESRD) as a long-term complication. Besides short-term complications, such as electrolyte and acid-base disorders, fluid overload, bleeding complications or immune dysfunctions, AKI can develop chronic injuries and subsequent CKD through renal fibrosis pathways. Kidney fibrosis is a pathological process defined by excessive extracellular matrix (ECM) deposition, evidenced in chronic kidney injuries with maladaptive architecture restoration. So far, cited maladaptive kidney processes responsible for AKI to CKD transition were epithelial, endothelial, pericyte, macrophage and fibroblast transition to myofibroblasts. These are responsible for smooth muscle actin (SMA) synthesis and abnormal renal architecture. Recently, AKI progress to CKD or ESRD gained a lot of interest, with impressive progression in discovering the mechanisms involved in renal fibrosis, including cellular and molecular pathways. Risk factors mentioned in AKI progression to CKD are frequency and severity of kidney injury, chronic diseases such as uncontrolled hypertension, diabetes mellitus, obesity and unmodifiable risk factors (i.e., genetics, older age or gender). To provide a better understanding of AKI transition to CKD, we have selected relevant and updated information regarding the risk factors responsible for AKIs unfavorable long-term evolution and mechanisms incriminated in the progression to a chronic state, along with possible therapeutic approaches in preventing or delaying CKD from AKI.

Leptospirosis kidney disease: Evolution from acute to chronic kidney disease

Leptospirosis is a neglected bacterial disease caused by leptospiral infection that carries a substantial mortality risk in severe cases. Research has shown that acute, chronic, and asymptomatic leptospiral infections are closely linked to acute and chronic kidney disease (CKD) and renal fibrosis. Leptospires affect renal function by infiltrating kidney cells via the renal tubules and interstitium and surviving in the kidney by circumventing the immune system. The most well-known pathogenic molecular mechanism of renal tubular damage caused by leptospiral infection is the direct binding of the bacterial outer membrane protein LipL32 to toll-like receptor-2 expressed in renal tubular epithelial cells (TECs) to induce intracellular inflammatory signaling pathways. These pathways include the production of tumor necrosis factor (TNF)-α and nuclear factor kappa activation, resulting in acute and chronic leptospirosis-related kidney injury. Few studies have investigated the relationship between acute and chronic renal diseases and leptospirosis and further evidence is necessary. In this review, we intend to discuss the roles of acute kidney injury (AKI) to/on CKD in leptospirosis. This study reviews the molecular pathways underlying the pathogenesis of leptospirosis kidney disease, which will assist in concentrating on potential future research directions.

Research Progress of Cordyceps sinensis and Its Fermented Mycelium Products on Ameliorating Renal Fibrosis by Reducing Epithelial-to-Mesenchymal Transition

Renal fibrosis is a hallmark and common outcome of various chronic kidney diseases (CKDs) and manifests pathologically as accumulation and deposition of extracellular matrix (ECM) in the kidney. Epithelial-to-mesenchymal transition (EMT) has been shown to be an important mechanism involved in renal fibrosis. Cordyceps sinensis, a traditional Chinese medicine, has long been used for the treatment of renal fibrosis. As research on the mycelium of C. sinensis progressed, a variety of medicines developed from fermented mycelium were used to treat CKD. However, their efficacies and mechanisms have not been fully summarized. In this review, five medicines developed from fermented mycelium of C. sinensis are presented. The pharmacodynamic effects of C. sinensis on different animal models of renal fibrosis are summarized. The in vitro studies and related mechanisms of C. sinensis on renal cells are detailed. Finally, the application and efficacy of these five commercial medicines that meet national standards in different types of CKD are summarized. From this review, it can be concluded that C. sinensis can alleviate various causes of renal fibrosis to some extent, and its mechanism is related to TGF-β1 dependent signaling, inhibition of inflammation, and improvement of renal function. Further research on rigorously designed, large-sample, clinically randomized controlled trial studies and detailed mechanisms should be conducted.

Fibrosis-the tale of H3K27 histone methyltransferases and demethylases

Fibrosis, or excessive scarring, is characterized by the emergence of alpha-smooth muscle actin (αSMA)-expressing myofibroblasts and the excessive accumulation of fibrotic extracellular matrix (ECM). Currently, there is a lack of effective treatment options for fibrosis, highlighting an unmet need to identify new therapeutic targets. The acquisition of a fibrotic phenotype is associated with changes in chromatin structure, a key determinant of gene transcription activation and repression. The major repressive histone mark, H3K27me3, has been linked to dynamic changes in gene expression in fibrosis through alterations in chromatin structure. H3K27-specific homologous histone methylase (HMT) enzymes, Enhancer of zeste 1 and 2 (EZH1, EZH2), which are the alternative subunits of the Polycomb Repressive Complex 2 (PRC2) and demethylase (KDM) enzymes, Ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX), and Lysine demethylase 6B (KDM6B), are responsible for regulating methylation status of H3K27me3. In this review, we explore how these key enzymes regulate chromatin structure to alter gene expression in fibrosis, highlighting them as attractive targets for the treatment of fibrosis.

Dickkopf-1 Acts as a Profibrotic Mediator in Progressive Chronic Kidney Disease

Chronic kidney disease (CKD) is a serious public health problem. Due to a high variability in the speed of CKD progression to end-stage renal disease (ESRD) and the critical involvement of Wnt/β-catenin signaling in CKD, we investigated the role of the Wnt antagonist Dickkopf-1 (DKK1) in CKD progression. Our data revealed that patients with CKD stages 4-5 had higher DKK1 levels in their serum and renal tissues than the control subjects. In an 8-year follow-up, the serum DKK1-high group in the enrolled CKD patients showed a faster progression to ESRD than the serum DKK1-low group. Using a rat model of 5/6 nephrectomy (Nx)-induced CKD, we consistently detected elevated serum levels and renal production of DKK1 in 5/6 Nx rats compared to sham-operated rats. Importantly, the knockdown of the DKK1 levels in the 5/6 Nx rats markedly attenuated the CKD-associated phenotypes. Mechanistically, we demonstrated that the treatment of mouse mesangial cells with recombinant DKK1 protein induced not only the production of multiple fibrogenic proteins, but also the expression of endogenous DKK1. Collectively, our findings suggest that DKK1 acts as a profibrotic mediator in CKD, and elevated levels of serum DKK1 may be an independent predictor of faster disease progression to ESRD in patients with advanced CKD.

Revisiting the Role of NAG across the Continuum of Kidney Disease

Acute and chronic kidney diseases are an evolving continuum for which reliable biomarkers of early disease are lacking. The potential use of glycosidases, enzymes involved in carbohydrate metabolism, in kidney disease detection has been under investigation since the 1960s. N-acetyl-beta-D-glucosaminidase (NAG) is a glycosidase commonly found in proximal tubule epithelial cells (PTECs). Due to its large molecular weight, plasma-soluble NAG cannot pass the glomerular filtration barrier; thus, increased urinary concentration of NAG (uNAG) may suggest injury to the proximal tubule. As the PTECs are the workhorses of the kidney that perform much of the filtration and reabsorption, they are a common starting point in acute and chronic kidney disease. NAG has previously been researched, and it is widely used as a valuable biomarker in both acute and chronic kidney disease, as well as in patients suffering from diabetes mellitus, heart failure, and other chronic diseases leading to kidney failure. Here, we present an overview of the research pertaining to uNAG’s biomarker potential across the spectrum of kidney disease, with an additional emphasis on environmental nephrotoxic substance exposure. In spite of a large body of evidence strongly suggesting connections between uNAG levels and multiple kidney pathologies, focused clinical validation tests and knowledge on underlining molecular mechanisms are largely lacking.

BaoShenTongLuo formula protects against podocyte injury by regulating AMPK-mediated mitochondrial biogenesis in diabetic kidney disease

BACKGROUND

Mitochondrial dysfunction is considered to be an important contributor in podocyte injury under diabetic conditions. The BaoShenTongLuo (BSTL) formula has been shown to reduce podocyte damage and postpone the progression of diabetic kidney disease (DKD). The potential mechanisms underlying the effects of BSTL, however, have yet to be elucidated. In this study, we aimed to investigate whether the effects of BSTL are related to the regulation of mitochondrial biogenesis via the adenosine monophosphate-activated protein kinase (AMPK) pathway.

METHODS

High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometer (HPLC-ESI-MS) analysis was performed to investigate the characteristics of pure compounds in BSTL. db/db mice and mouse podocyte clone-5 (MPC5) cells were exposed to high glucose (HG) to induce DKD and podocyte damage. Body weight, random blood glucose, urinary albumin/creatinine ratio (UACR), indicators of renal function and renal histological lesions were measured. Markers of podocyte injury, mitochondrial morphology, mitochondrial deoxyribonucleic acid (mtDNA) content, mitochondrial respiratory chain complexes activities, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) levels were assessed. Protein expressions of AMPK, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), transcription factor A (TFAM), mitochondrial fusion protein 2 (MFN2) and dynamin-related protein 1 (DRP1) were also detected. MPC5 cells were transfected with AMPKα small interfering RNA (AMPKα siRNA) to determine the underlying mechanisms of BSTL improvement of mitochondrial function under diabetic conditions.

RESULTS

In vivo, treatment with BSTL reduced the UACR levels, reversed the histopathological changes in renal tissues, and alleviated the podocyte injury observed in db/db mice. After BSTL treatment, the decreased mtDNA content and mitochondrial respiratory chain complex I, III, and IV activities were significantly improved, and these effects were accompanied by maintenance of the protein expression of p-AMPKαT172, PGC-1α, TFAM and MFN2. The in vitro experiments also showed that BSTL reduced podocyte apoptosis, suppressed excessive cellular ROS production, and reversed the decreased in MMP that were observed under HG conditions. More importantly, the effects of BSTL in enhancing mitochondrial biogenesis and reducing podocyte apoptosis were inhibited in AMPKα siRNA-treated podocytes.

CONCLUSION

BSTL plays a crucial role in protecting against podocyte injury by regulating the AMPK-mediated mitochondrial biogenesis in DKD.

Elevated Levels of Plasma Collagen Triple Helix Repeat Containing 1 (CTHRC1) Is Strongly Associated with eGFR and Albuminuria in Chronic Kidney Disease

Background: Chronic kidney disease (CKD) has various etiologies, making it impossible to fully understand its complex pathophysiology. Elevated levels of plasma creatinine, proteinuria, and albuminuria and declined eGFR are traits observed in CKD patients. The current study attempts to highlight the collagen triple helix repeat containing 1 (CTHRC1) protein as a putative blood biomarker for CKD in addition to existing recognized indicators of CKD progression. Methods: A total of 26 CKD patients and 18 healthy controls were enrolled in this study. Clinical characteristics and complete blood and biochemical analyses were collected, and human ELISA kits were used to detect possible CKD biomarkers. Results: The study’s findings showed that CTHRC1 correlates with key clinical markers of kidney function such as 24 h urine total protein, creatinine, urea, and uric acid. In addition, CTHRC1 demonstrated a strong significant difference (p ≤ 0.0001) between the CKD and control group. Conclusions: Our research demonstrates that the plasma level of CTHRC1 can distinguish between those with CKD and healthy patients. Plasma CTHRC1 levels may aid in the diagnosis of CKD given the current state of knowledge, and these results call for further investigation in a wider, more diverse patient group.

The Therapeutic Mechanism of Schisandrol A and Its Metabolites on Pulmonary Fibrosis Based on Plasma Metabonomics and Network Analysis

Background

Schisandrol A (Sch A) is the main active ingredient of Schisandra chinensis (Turcz.) Baill. Our previous study showed that Sch A has anti-pulmonary fibrosis (PF) activity, but its metabolic-related mechanisms of action are not clear.

Methods

Here, we explored the therapeutic mechanisms of Sch A on PF by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) metabolomics approach and network analysis. The metabolites of Sch A in mice (bleomycin + Sch A high-dose group) plasma were identified based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS).

Results

32 metabolites were detected reversed to normal level after treating bleomycin (BLM)-induced PF mice with Sch A. The 32 biomarkers were enriched in energy metabolism and several amino acid metabolisms, which was the first report on the therapeutic effects of Sch A on PF through rescuing the disordered energy metabolism. The UPLC-Q-TOF/MS analysis identified 17 possible metabolites (including isomers) of Sch A in mice plasma. Network analysis revealed that Sch A and 17 metabolites were related to 269 genes, and 1109 disease genes were related to PF. The construction of the Sch A/metabolites-target-PF network identified a total of 79 intersection genes and the TGF-β signaling pathway was determined to be the main signaling pathway related to the treatment of PF by Sch A. The integrated approach involving metabolomics and network analysis revealed that the TGF-β1-ID3-creatine pathway, TGF-β1-VIM-carnosine pathway were two of the possible pathways Sch A regulated to modulate metabolic disorders, especially energy metabolism, and the metabolite of Sch A M5 was identified as a most likely active metabolite.

Conclusion

The results suggested the feasibility of combining metabolomics and network analysis to reflect the effects of Sch A on the biological network and the metabolic state of PF and to evaluate the drug efficacy of Sch A and its related mechanisms.

Integrative phosphatidylcholine metabolism through phospholipase A2 in rats with chronic kidney disease

Dysregulation in lipid metabolism is the leading cause of chronic kidney disease (CKD) and also the important risk factors for high morbidity and mortality. Although lipid abnormalities were identified in CKD, integral metabolic pathways for specific individual lipid species remain to be clarified. We conducted ultra-high-performance liquid chromatography-high-definition mass spectrometry-based lipidomics and identified plasma lipid species and therapeutic effects of Rheum officinale in CKD rats. Adenine-induced CKD rats were administered Rheum officinale. Urine, blood and kidney tissues were collected for analyses. We showed that exogenous adenine consumption led to declining kidney function in rats. Compared with control rats, a panel of differential plasma lipid species in CKD rats was identified in both positive and negative ion modes. Among the 50 lipid species, phosphatidylcholine (PC), lysophosphatidylcholine (LysoPC) and lysophosphatidic acid (LysoPA) accounted for the largest number of identified metabolites. We revealed that six PCs had integral metabolic pathways, in which PC was hydrolysed into LysoPC, and then converted to LysoPA, which was associated with increased cytosolic phospholipase A2 protein expression in CKD rats. The lower levels of six PCs and their corresponding metabolites could discriminate CKD rats from control rats. Receiver operating characteristic curves showed that each individual lipid species had high values of area under curve, sensitivity and specificity. Administration of Rheum officinale significantly improved impaired kidney function and aberrant PC metabolism in CKD rats. Taken together, this study demonstrates that CKD leads to PC metabolism disorders and that the dysregulation of PC metabolism is involved in CKD pathology.

IKKα aggravates renal fibrogenesis by positively regulating the Wnt/β-catenin pathway

AKI (acute kidney injury) with maladaptive repair plays exacerbated role in renal fibrosis characterized by tubulointerstitial fibrosis. Previously, we reported that IKKα contributed to kidney regeneration and inhibited inflammation. Here, we first identified the role and mechanism of IKKα on TGF-β1-induced fibrosis in human tubular epithelial cells and fibrotic kidneys. IKKα was up-regulated in kidney tubular epithelium in unilateral ureteral obstruction (UUO) and unilateral ischemic reperfusion injury (UIRI) mice. Immunohistochemical staining showed that IKKα was positively correlated with the extent of kidney fibrosis in tissue biopsies from chronic kidney disease (CKD) patients. Compared with wild-type controls, Ksp-IKKα^-/- mice exhibited inactivated Wnt/β-catenin pathway, decreased serum creatinine and interstitial fibrosis in the kidney after IRI. In TGF-β1-stimulated human tubular epithelial cells, IKKα overexpression enhanced β-catenin nuclear translocation. Blocking IKKα by siRNA specifically suppressed β-catenin activation and downstream profibrotic genes such as fibronectin and α-smooth muscle actin (α-SMA). Taken together, our study demonstrated that IKKα aggravated renal fibrogenesis by activating Wnt/β-catenin signalling pathway, providing a new target for the treatment of kidney fibrosis.

A study of the molecular mechanism of quercetin and dasatinib combination as senolytic in alleviating age-related and kidney diseases

Aging is a significant risk factor for the majority of prevalent human illnesses. The chance of having severe chronic conditions grows dramatically with advancing age. Indeed, more than 90% of people over 65 get at least one chronic disease, including diabetes, heart disease, malignancy, memory loss, and kidney disease, whereas more than 70% have two or more of these ailments. Mouse and human aging lead to increased senescent cells and decreased klotho concentrations. Mice lacking the protein α-klotho show faster aging, similar to human aging. α-Klotho upregulation extends life and slows or suppresses the onset of many age-related illnesses and kidney diseases. Like the consequences of α-klotho deficiency, senescent cell accumulation is linked to tissue dysfunction in various organs and multiple age-related kidney diseases. In addition, α-klotho and cell senescence are negatively and presumably mechanistically linked. Earlier research has demonstrated that klotho exerts its protective effects in age-related and kidney disease by interacting with Wnt ligands, serving as an endogenous antagonist of Wnt/β-catenin signaling. In addition, decreasing senescent cell burden with senolytics, a class of drugs that remove senescent cells selectively and extend the life span of mice. In this work, we are studying the molecular mechanism of the combination of quercetin and dasatinib as senolytic in easing age-related chronic renal illness by altering the level of klotho/Wnt/β-catenin. PRACTICAL APPLICATIONS: There is an inverse relationship between the onset and the development of age-related disorders and cellular senescence and Klotho. Earlier attempts to suppress transforming growth factor-beta 1 (TGF-β1) in kidney disease with anti-TGF-β1 antibodies were ineffective, and this should be kept in mind. Senolytic medications may benefit from targeting senescent cells, which enhances the protective factor α-klotho. In addition, our study provides a unique, translationally feasible route for creating orally active small compounds to enhance α-klotho, which may also be a valuable biomarker for age-related kidney disease. Additionally, other aspects of aging can be affected by senolytics, such as limiting age-related mitochondrial dysfunction, lowering inflammation and fibrosis, blunting reactive oxygen species (ROS) generation, decreasing deoxyribonucleic acid (DNA) damage, and reinforcing insulin sensitivity. Senolytic agents have been shown to increase adipose progenitor and cardiac progenitor cell activity in aging animals and animals with cellular senescence-related diseases, such as heart, brain, and kidney disease.

Cell-Matrix Interactions in Renal Fibrosis

Renal fibrosis is a hallmark of end-stage chronic kidney disease. It is characterized by increased accumulation of extracellular matrix (ECM), which disrupts cellular organization and function within the kidney. Here, we review the bi-directional interactions between cells and the ECM that drive renal fibrosis. We will discuss the cells involved in renal fibrosis, changes that occur in the ECM, the interactions between renal cells and the surrounding fibrotic microenvironment, and signal transduction pathways that are misregulated as fibrosis proceeds. Understanding the underlying mechanisms of cell-ECM crosstalk will identify novel targets to better identify and treat renal fibrosis and associated renal disease.

Anti-EMT and anti-fibrosis effects of protocatechuic aldehyde in renal proximal tubular cells and the unilateral ureteral obstruction animal model

CONTEXT

Protocatechuic aldehyde (PCA) is a natural product that has various benefits for fibrosis.

OBJECTIVE

This study evaluated the effects of PCA on renal fibrosis.

MATERIALS AND METHODS

Epithelial-mesenchymal transition (EMT) was induced by 20 ng/mL transforming growth factor-β1 (TGF-β1), followed by treatment with 1 and 5 μM PCA, in the rat renal proximal tubular cell line NRK-52E. Cell viability, protein expression, and scratch wound-healing assays were conducted. Sprague-Dawley (SD) rats underwent unilateral ureteral obstruction (UUO) surgery for renal fibrosis indication and were treated with 50 and 100 mg/kg PCA for 14 days.

RESULTS

The IC₅₀ of PCA was appropriately 13.75 ± 1.91 μM in NRK-52E cells, and no significant difference at concentrations less than 5 μM. PCA ameliorated TGF-β1-induced EMT, such as enhanced E-cadherin and decreased vimentin. Fibrotic markers collagen IV and α-smooth muscle actin (α-SMA) increased in TGF-β1-induced NRK-52E. Moreover, PCA reduced TGF-β1-induced migration in the wound-healing assay. Analysis of rat kidneys indicated that PCA reduced UUO-induced hydronephrosis (control: 15.11 ± 1.00%; UUO: 39.89 ± 1.91%; UUO + PCA50: 18.37 ± 1.61%; UUO + PCA100: 17.67 ± 1.39%). Protein level demonstrated that PCA not only decreased vimentin expression and enhanced E-cadherin expression, but inhibited UUO-induced collagen IV and α-SMA upregulation, indicating that it could mitigate EMT in a rat model of UUO-induced renal fibrosis.

DISCUSSION AND CONCLUSIONS

This study suggested that PCA decreases TGF-β1-induced fibrosis and EMT in vitro and in vivo. These findings demonstrate pharmacological effects of PCA and might be a potential strategy for the prevention of organ fibrosis in clinics.

Intrarenal 1-methoxypyrene, an aryl hydrocarbon receptor agonist, mediates progressive tubulointerstitial fibrosis in mice

Recent studies have shown that endogenous metabolites act via aryl hydrocarbon receptor (AhR) signalling pathway in tubulointerstitial fibrosis (TIF) pathogenesis. However, the mechanisms underlying endogenous metabolite-mediated AhR activation are poorly characterised. In this study, we conducted untargeted metabolomics analysis to identify the significantly altered intrarenal metabolites in a mouse model of unilateral ureteral obstruction (UUO). We found that the levels of the metabolite 1-methoxypyrene (MP) and the mRNA expression of AhR and its target genes CYP1A1, CYP1A2, CYP1B1 and COX-2 were progressively increased in the obstructed kidney at Weeks 1, 2 and 3. Furthermore, these changes were positively correlated with progressive TIF in UUO mice. In NRK-52E, RAW 264.7 and NRK-49F cells, MP dose-dependently upregulated the mRNA expression of AhR and its four target genes and the protein expression of nuclear AhR, accompanied by the upregulated protein expression of collagen I, α-SMA and fibronectin, as well as downregulated E-cadherin expression. Consistently, oral administration of MP in mice progressively enhanced AhR activity and upregulated profibrotic protein expression in the kidneys; these effects were partially inhibited by AhR knockdown in MP-treated mice and cell lines. In addition, we screened and identified erythro-guaiacylglycerol-β-ferulic acid ether (GFA), which was isolated from Semen plantaginis, as a new AhR antagonist. GFA significantly attenuated TIF in MP-treated NRK-52E cells and mice by partially antagonising AhR activity. Our results suggest that MP activates AhR signalling, thus mediating TIF through epithelial-mesenchymal transition and macrophage-myofibroblast transition. MP is a crucial metabolite that contributes to TIF via AhR signalling pathway.

T-2 Toxin Induces Kidney Fibrosis via the mtROS-NLRP3-Wnt/β-Catenin Axis

T-2 toxin causes kidney fibrosis. Wnt/β-catenin signaling promotes kidney fibrosis when sustained and activated. However, whether T-2-induced kidney fibrosis involves Wnt/β-catenin signaling activation has not been explored yet. T-2 toxin causes renal mitochondrial damage, leading to mitochondrial reactive oxygen species (mtROS) overproduction and NLRP3-inflammasome activation. The activated NLRP3-inflammasome can mediate fibrosis. However, whether the NLRP3-inflammasome can be mediated by mtROS and further regulate T-2-induced kidney fibrosis through Wnt/β-catenin signaling is unclear. In this study, first, we confirmed that T-2 toxin caused Wnt/β-catenin signaling activation in mice kidneys and HK-2 cells. Second, we confirmed that mtROS activated the NLRP3-inflammasome in T-2-exposed mice kidneys and HK-2 cells. Third, we confirmed that the NLRP3-inflammasome regulated the Wnt/β-catenin signaling in T-2 toxin-exposed mice kidneys and HK-2 cells. Finally, we confirmed that Wnt/β-catenin signaling regulated fibrosis in T-2 toxin-exposed mice kidneys and HK-2 cells. The above results confirm that T-2 toxin induces kidney fibrosis via the mtROS-NLRP3-Wnt/β-catenin axis.

Inhibition of RIP1-RIP3-mediated necroptosis attenuates renal fibrosis via Wnt3α/β-catenin/GSK-3β signaling in unilateral ureteral obstruction

Renal fibrosis represents the final common outcome of chronic kidney disease of virtually any etiology. However, the mechanism underlying the evolution of renal fibrosis remains to be addressed. This study sought to clarify whether RIP1-RIP3-mediated necroptosis is involved in renal fibrosis via Wnt3α/β-catenin/GSK-3β signaling in vitro and in a rat model of unilateral ureteral obstruction (UUO). Rats with UUO were administered RIP inhibitors (necrostatin-1 or GSK872) or β-catenin/TCF inhibitor ICG-001 daily for 7 consecutive days. UUO caused significant renal tubular necrosis and overexpression of RIP1-RIP3-MLKL axis proteins, and was accompanied by activation of the NLRP3 inflammasome and renal fibrosis. Oxidative stress caused by UUO was closely associated with endoplasmic reticulum stress and mitochondrial dysfunction, which resulted in apoptotic cell death via Wnt3α/β-catenin/GSK-3β signaling. All of these effects were abolished by an RIP inhibitor (necrostatin-1 or GSK872) or ICG-001. In H2O2-treated HK-2 cells, both RIP inhibitor and ICG-001 decreased intracellular reactive oxygen species production and apoptotic cells, but increased cell viability. Activated Wnt3α/β-catenin/GSK-3β signaling was decreased by either RIP inhibitor or ICG-001. Our findings suggest that RIP1-RIP3-mediated necroptosis contributes to the development of renal fibrosis via Wnt3α/β-catenin/GSK-3β signaling in UUO and may be a therapeutic target for protection against renal scarring of other origins.

Chuan Huang Fang combining reduced glutathione in treating acute kidney injury (grades 1–2) on chronic kidney disease (stages 2–4): A multicenter randomized controlled clinical trial

Lack of effective drugs for acute kidney injury (AKI) grades 1–2 is a crucial challenge in clinic. Our previously single-center clinical studies indicated Chuan Huang Fang (CHF) might have nephroprotection in AKI on chronic kidney disease (CKD) (A on C) patients by preventing oxidant damage and inhibiting inflammation. Reduced glutathione (RG) has recently been shown to increase the clinical effectiveness of high-flux hemodialysis among patients with severe AKI. In this multicenter randomized controlled clinical study, we designed a new protocol to assess the efficacy and safety of CHF combining RG in patients with A on C. We also explored therapeutic mechanisms from renal fibrosis biomarkers. 98 participants were randomly and equally divided into the RG and RG + CHF subgroups. The RG and RG + CHF groups received general treatments with RG and a combination of RG and CHF, respectively. The therapy lasted for 2 weeks. In this study, the primary assessment result was a difference in the slope of serum creatinine (Scr) over the course of 2 weeks. The secondary evaluation outcomes were alterations in blood urea nitrogen (BUN), uric acid (UA), estimated glomerular filtration rate (eGFR), urinary AKI biomarkers, renal fibrosis biomarkers (transforming growth factor-β₁ (TGF-β₁), connective tissue growth factor (CTGF)), and traditional Chinese medicine (TCM) symptoms. Furthermore, vital signs and adverse events (AEs) were observed. Both groups had a slower renal function decline after treatment than before treatment. Compared with RG group, more reductions of Scr, BUN, UA, and better improvement of eGFR were observed in RG + CHF group (p < 0.05). Additionally, the levels of urinary AKI biomarkers, renal fibrosis biomarkers, and TCM syndromes were decreased in RG + CHF group versus RG group (p < 0.05). No significant between-group differences were observed of AEs. We thus concluded this novel therapy of CHF combining RG might be a useful method for treating A on C patients.

Membranous nephropathy: Systems biology-based novel mechanism and traditional Chinese medicine therapy

Membranous nephropathy (MN) is a renal-limited non-inflammatory autoimmune disease in the glomerulus, which is the second or third main cause of end-stage kidney diseases in patients with primary glomerulonephritis. Substantial achievements have increased our understanding of the aetiology and pathogenesis of murine and human MN. The identification of nephritogenic autoantibodies against neutral endopeptidase, phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A) antigens provide more specific concept-driven intervention strategies for treatments by specific B cell-targeting monoclonal antibodies to inhibit antibody production and antibody-antigen immune complex deposition. Furthermore, additional antibody specificities for antigens have been discovered, but their pathogenic effects are uncertain. Although anti-PLA2R and anti-THSD7A antibodies as a diagnostic marker is widely used in MN patients, many questions including autoimmune response development, antigenic epitopes, and podocyte damage signalling pathways remain unresolved. This review describes the current available evidence regarding both established and novel molecular mechanisms based on systems biology approaches (gut microbiota, long non-coding RNAs, metabolite biomarkers and DNA methylation) in MN, with an emphasis on clinical findings. This review further summarizes the applications of traditional Chinese medicines such as Tripterygium wilfordii and Astragalus membranaceus for MN treatment. Lastly, this review considers how the identification of novel antibodies/antigens and unresolved questions and future challenges reveal the pathogenesis of MN.

Shenkang injection improves chronic kidney disease by inhibiting multiple renin-angiotensin system genes by blocking the Wnt/β-catenin signalling pathway

Chronic kidney disease (CKD) is a major worldwide public health problem. The increase in the number of patients with CKD and end-stage kidney disease requesting renal dialysis or transplantation will progress to epidemic proportions in the next several decades. Although blocking the renin-angiotensin system (RAS) has been used as a first-line standard therapy in patients with hypertension and CKD, patients still progress towards end-stage kidney disease, which might be closely associated with compensatory renin expression subsequent to RAS blockade through a homeostatic mechanism. The Wnt/β-catenin signalling pathway is the master upstream regulator that controls multiple intrarenal RAS genes. As Wnt/β-catenin regulates multiple RAS genes, we inferred that this pathway might also be implicated in blood pressure control. Therefore, discovering new medications to synchronously target multiple RAS genes is necessary and essential for the effective treatment of patients with CKD. We hypothesized that Shenkang injection (SKI), which is widely used to treat CKD patients, might ameliorate CKD by inhibiting the activation of multiple RAS genes via the Wnt/β-catenin signalling pathway. To test this hypothesis, we used adenine-induced CKD rats and angiotensin II (AngII)-induced HK-2 and NRK-49F cells. Treatment with SKI inhibited renal function decline, hypertension and renal fibrosis. Mechanistically, SKI abrogated the increased protein expression of multiple RAS elements, including angiotensin-converting enzyme and angiotensin II type 1 receptor, as well as Wnt1, β-catenin and downstream target genes, including Snail1, Twist, matrix metalloproteinase-7, plasminogen activator inhibitor-1 and fibroblast-specific protein 1, in adenine-induced rats, which was verified in AngII-induced HK-2 and NRK-49F cells. Similarly, our results further indicated that treatment with rhein isolated from SKI attenuated renal function decline and epithelial-to-mesenchymal transition and repressed RAS activation and the hyperactive Wnt/β-catenin signalling pathway in both adenine-induced rats and AngII-induced HK-2 and NRK-49F cells. This study first revealed that SKI repressed epithelial-to-mesenchymal transition by synchronously targeting multiple RAS elements by blocking the hyperactive Wnt/β-catenin signalling pathway.

Recent advances of gut microbiota in chronic kidney disease patients

Chronic kidney disease (CKD) is a worldwide public health issue and has ultimately progressed to an end-stage renal disease that requires life-long dialysis or renal transplantation. However, the underlying molecular mechanism of these pathological development and progression remains to be fully understood. The human gut microbiota is made up of approximately 100 trillion microbial cells including anaerobic and aerobic species. In recent years, more and more evidence has indicated a clear association between dysbiosis of gut microbiota and CKD including immunoglobulin A (IgA) nephropathy, diabetic kidney disease, membranous nephropathy, chronic renal failure and end-stage renal disease. The current review describes gut microbial dysbiosis and metabolites in patients with CKD thus helping to understand human disease. Treatment with prebiotics, probiotics and natural products can attenuate CKD through improving dysbiosis of gut microbiota, indicating a novel intervention strategy in patients with CKD. This review also discusses therapeutic options, such as prebiotics, probiotics and natural products, for targeting dysbiosis of gut microbiota in patients to provide more specific concept-driven therapy strategy for CKD treatment.

Research Progress of Chinese Herbal Medicine Intervention in Renal Interstitial Fibrosis

Chronic kidney diseases usually cause renal interstitial fibrosis, the prevention, delay, and treatment of which is a global research hotspot. However, no definite treatment options are available in modern medicine. Chinese herbal medicine has a long history, rich varieties, and accurate treatment effects. Hitherto, many Chinese herbal medicine studies have emerged to improve renal interstitial fibrosis. This paper reviews the mechanisms of renal interstitial fibrosis and recent studies on the disease intervention with Chinese herbal medicine through literature search, intend to reveal the importance of Chinese herbal medicine in renal interstitial fibrosis. The results show that Chinese herbal medicine can improve renal interstitial fibrosis, and the effects of Chinese herbal medicine on specific pathological mechanisms underlying renal interstitial fibrosis have been explored. Additionally, the limitations and advantages of Chinese herbal medicine in the treatment of renal interstitial fibrosis, possible research directions, and new targets of Chinese herbal medicine are discussed to provide a basis for studies of renal interstitial fibrosis.

Recent Advances in Clinical Diagnosis and Pharmacotherapy Options of Membranous Nephropathy

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome among adults, which is the leading glomerular disease that recurs after kidney transplantation. Treatment for MN remained controversial and challenging, partly owing to absence of sensitive and specific biomarkers and effective therapy for prediction and diagnosis of disease activity. MN starts with the formation and deposition of circulating immune complexes on the outer area in the glomerular basement membrane, leading to complement activation. The identification of autoantibodies against the phospholipase A₂ receptor (PLA₂R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) antigens illuminated a distinct pathophysiological rationale for MN treatments. Nowadays, detection of serum anti-PLA₂R antibodies and deposited glomerular PLA₂R antigen can be routinely applied to MN. Anti-PLA₂R antibodies exhibited much high specificity and sensitivity. Measurement of PLA₂R in immune complex deposition allows for the diagnosis of PLA₂R-associated MN in patients with renal biopsies. In the review, we critically summarized newer diagnosis biomarkers including PLA₂R and THSD7A tests and novel promising therapies by using traditional Chinese medicines such as Astragalus membranaceus, Tripterygium wilfordii, and Astragaloside IV for the treatment of MN patients. We also described unresolved questions and future challenges to reveal the diagnosis and treatments of MN. These unprecedented breakthroughs were quickly translated to clinical diagnosis and management. Considerable advances of detection methods played a critical role in diagnosis and monitoring of treatment.

Loss of Proximal Tubular Sirtuin 6 Aggravates Unilateral Ureteral Obstruction-Induced Tubulointerstitial Inflammation and Fibrosis by Regulation of β-Catenin Acetylation

Renal fibrosis is a significant pathologic change associated with progressive kidney disease. Sirt6 is an NAD⁺-dependent deacetylase and mono-ADP ribosyltransferase known to play diverse roles in the processes attendant to aging, metabolism, and carcinogenesis. However, the role of proximal tubule-specific Sirt6 in renal fibrosis remains elusive. This study investigates the effect of proximal tubule-specific Sirt6 knockdown on unilateral ureteral obstruction (UUO)-induced renal tubulointerstitial inflammation and fibrosis. Renal fibrosis in wild type and PT-Sirt6KO (Sirt6^flox/flox; Ggt1-Cre⁺) mice was induced by UUO surgery. After seven days, histologic examination and Western blot analysis were performed to examine extracellular matrix (ECM) protein expression. We evaluated inflammatory cytokine and cell adhesion molecule expression after ureteral obstruction. The therapeutic effect of Sirt6 activator MDL-800 on UUO-induced tubulointerstitial inflammation and fibrosis was assessed. The loss of Sirt6 in the proximal tubules aggravated UUO-induced tubular injury, ECM deposition, F4/80 positive macrophage infiltration, and proinflammatory cytokine and chemokine expression. Sirt6 activator MDL-800 mitigated UUO-induced renal tubulointerstitial inflammation and fibrosis. In an in vitro experiment, MDL-800 decreases the transforming growth factor (TGF)-β1-induced activation of myofibroblast and ECM production by regulating Sirt6-dependent β-catenin acetylation and the TGF-β1/Smad signaling pathway. In conclusion, proximal tubule Sirt6 may play an essential role in UUO-induced tubulointerstitial inflammation and fibrosis by regulating Sirt6-dependent β-catenin acetylation and ECM protein promoter transcription.

Effect of FLOT2 Gene Expression on Invasion and Metastasis of Colorectal Cancer and Its Molecular Mechanism under Nanotechnology and RNA Interference

The study is aimed at investigating the effect of the FLOT2 gene on invasion and metastasis of colorectal cancer (CRC) cells and the corresponding molecular mechanism by preparing polylysine-silicon nanoparticles. Specifically, polylysine was used to modify the silica nanoparticles prepared by the emulsification method to obtain polylysine-silicon nanoparticles. The characterization of polylysine-silicon nanoparticles was completed by nanoparticle size analyzer, laser particle size potentiometer, and transmission microscope. The influence of polylysine-silicon nanoparticles on the survival rate of CRC cell line HT-29 was detected using the method of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). The FLOT2-siRNA expression vector was constructed and transfected with HT-29. The HT-29 transfected with empty plasmid was used as the negative control (NC). Western Blot (WB) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect expression levels of FLOT2 gene and epithelial-mesenchymal transition- (EMT-) related genes. Transwell invasion assay, Transwell migration assay, and CCK8 assay were used to detect the cell invasion, migration, and proliferation. The results showed that the average particle size of polylysine-silicon nanoparticles was 30 nm, the potential was 19.65 mV, the particle size was 65.8 nm, and the dispersion coefficient was 0.103. At the same concentration, the toxicity of silicon nanoparticles to HT-29 was significantly lower than that of liposome reagent, and the transfection efficiency was 60%, higher than that of liposome reagent (40%). The mRNA level and protein expression of the FLOT2 gene in the FLOT2-siRNA group were significantly lower than those in the NC group (P < 0.01). The optical density (OD) value of the NC group and the blank control (CK) group were significantly higher than that of FLOT2-siRNA cells (P < 0.01). The OD value of FLOT2-siRNA cells was lower than that of NC cells at 48 h, 72 h, and 96 h (P < 0.01). The mRNA levels and protein expressions of MMP2 and vimentin in the FLOT2-siRNA group were significantly lower than those in the NC group and CK group (P < 0.01). The mRNA level and protein expression of the E-cadherin gene in the FLOT2-siRNA group were significantly higher than those in the NC group and CK group (P < 0.01). In conclusion, an RNA interference plasmid with high transfection efficiency and low cytotoxicity was established based on nanotechnology. siRNA-mediated FLOT2 protein inhibits the invasion, migration, and proliferation of CRC cells by regulating the expression changes of EMT-related genes, which provides a scientific basis for clinical treatment of CRC.

Natural Products Against Renal Fibrosis via Modulation of SUMOylation

Renal fibrosis is the common and final pathological process of kidney diseases. As a dynamic and reversible post-translational modification, SUMOylation and deSUMOylation of transcriptional factors and key mediators significantly affect the development of renal fibrosis. Recent advances suggest that SUMOylation functions as the promising intervening target against renal fibrosis, and natural products prevent renal fibrosis via modulating SUMOylation. Here, we introduce the mechanism of SUMOylation in renal fibrosis and therapeutic effects of natural products. This process starts by summarizing the key mediators and enzymes during SUMOylation and deSUMOylation and its regulation role in transcriptional factors and key mediators in renal fibrosis, then linking the mechanism findings of SUMOylation and natural products to develop novel therapeutic candidates for treating renal fibrosis, and concludes by commenting on promising therapeutic targets and candidate natural products in renal fibrosis via modulating SUMOylation, which highlights modulating SUMOylation as a promising strategy for natural products against renal fibrosis.

Extract of Corallodiscus flabellata attenuates renal fibrosis in SAMP8 mice via the Wnt/β-catenin/RAS signaling pathway

BACKGROUND

Fibrosis is one of the most common pathological features of the aging process of the kidney, and fibrosis in aging kidneys also aggravates the process of chronic kidney disease (CKD). Corallodiscus flabellata B. L. Burtt (C. flabellata, CF) is a commonly used botanical drug in Chinese folklore. However, few studies have reported its pharmacological effects. This study aimed to explore the effect of CF ethanol extract on renal fibrosis in SAMP8 mice and identify potentially active compounds.

METHODS

Senescence-accelerated mouse-prone 8 (SAMP8) were used as animal models, and different doses of CF were given by gavage for one month. To observe the degree of renal aging in mice using β-galactosidase staining. Masson staining and the expression levels of Col-I, α-SMA, and FN were used to evaluate the renal fibrosis in mice. The protein expression levels of Nrf2 pathway and Wnt/β-catenin/RAS pathway in the kidney were measured. And β-galactosidase (β-gal) induced NRK-52E cells as an in vitro model to screen the active components of CF.

RESULTS

The CF ethanol extract significantly inhibited the activity of renal β-galactosidase and the expression levels of Col-I, α-SMA, and FN in SAMP8 mice, and improved Masson staining in SAMP8 mice. CF remarkably reduced urinary protein, creatinine, urea nitrogen and serum levels of TNF-α and IL-1β in SAMP8 mice, and significantly increased the levels of SOD and GSH-Px. Moreover, CF activated the Nrf2 pathway and blocked the Wnt/β-catenin/RAS pathway in the kidneys of mice. Besides, 3,4-dihydroxyphenylethanol (SDC-0-14, 16) and (3,4-dihydroxyphenylethanol-8-O-[4-O-trans-caffeoyl-β-D-apiofuranosyl-(1→3)-β-D-glucopyranosyl (1→6)]-β-D-glucopyranoside (SDC-1-8) were isolated from CF, which reduced the senescence of NRK-52E cells, and maybe the active ingredients of CF playing the anti-aging role.

CONCLUSIONS

Our experiments illuminated that CF ethanol extract may ameliorate renal fibrosis in SAMP8 mice via the Wnt/β-catenin/RAS pathway. And SDC-0-14,16 and SDC-1-8 may be the material basis for CF to exert anti-renal senescence-related effects.

Proanthocyanidins Protect Against Cadmium-Induced Diabetic Nephropathy Through p38 MAPK and Keap1/Nrf2 Signaling Pathways

Diabetic nephropathy (DN) is one of the most devastating complications of diabetes mellitus. Although cadmium (Cd) exposure might be involved in the pathogenesis of DN, the underlying mechanism is still unclear. In this study, we explored the protective effects and possible mechanism of proanthocyanidins (OPC) from grape seed using a mouse model of Cd-induced DN. The successful establishment of this model was verified by analyzing the physiological and biochemical indices of mice, including their body weight and tissue ratio; levels of blood glucose, creatinine, microalbumin, total cholesterol, triglycerides, high-density lipoprotein-cholesterol and low-density lipoprotein-cholesterol; and was based on histopathological examination. Oxidative-antioxidative status, elemental analysis, and key signaling pathway analysis were performed to explore the possible protective mechanism of OPC. The protective effects of OPC and its possible mechanism in preventing the progression of DN were investigated using a multidimensional approach, including its ability in regulating oxidative-antioxidative status (lipid peroxidation, protein carbonyl, superoxide dismutase, and glutathione GST, GSH-Px), metal-binding ability (Cd levels in the kidneys and urine and MT content) and mediation of essential elements (Zn, Ca, Cu, and Fe levels in the kidneys), and activation of the p38 MAPK and Keap1/Nrf2 signaling pathways. OPC exhibited a significant renoprotective effect, attributed to the metal-chelating ability, anti-oxidative effect, and mediation of oxidative stress-related signaling pathway. These results highlight the potential of OPC in preventing or treating DN in humans and suggest the dietary intake of grapes, which are rich in polyphenols, for the prevention of type 2 diabetes mellitus and its complications.