Selective EZH2 inhibitor zld1039 alleviates inflammation in cisplatin-induced acute kidney injury partially by enhancing RKIP and suppressing NF-κB p65 pathway

Prenatal arsenic exposure alters EZH2/H3K27me3 to induce RKIP/NF-kB/ERK1/2-mediated early-onset kidney disease in mouse offspring

The rising incidences of chronic kidney disease (CKD) and renal failure are a major public health concern. Arsenic, a widespread water contaminant and environmental toxicant, is well-known to contribute to kidney disease in adults. However, its long-term effects on kidney health following early-life exposure remain poorly understood. Therefore, we investigated the impact of prenatal arsenic exposure on kidney health in offspring using a BALB/c mouse model. 0.4 ppm arsenic, an environmentally relevant dose, was orally administered to female mice from 15 days before mating until delivery. Structural and ultrastructural changes in the kidney were assessed using histopathology and transmission electron microscopy, while markers of inflammation, kidney injury, and function were evaluated through Luminex assays, FITC-sinistrin-based glomerular filtration rate (GFR), real-time PCR, immunohistochemistry, and immunoblotting. Notably, arsenic-exposed offspring showed reduced body weight, crown-to-rump length, inflammation, and early signs of kidney injury on postnatal day 2 (PND-2). By 6 weeks, examination showed tubular dilation, mitochondrial damage, vacuolated cytoplasm, and basement membrane disruption were more evident in the kidneys. Furthermore, elevated levels of kidney injury markers, including kidney injury molecule-1, beta-2 microglobulin, cystatin C, and tissue inhibitor of metalloproteinase 1, were detected in urine. These changes were accompanied by increased serum creatinine and a decline in kidney function, as evidenced by reduced GFR levels. Proinflammatory cytokines (TNF-α, IL-6) and NF-κB were significantly elevated along with an increased immune cell infiltration in the kidneys of arsenic-exposed offspring. Further analysis showed increased mesenchymal markers fibronectin and alpha-smooth muscle actin and reduced epithelial marker E-cadherin in the kidneys, indicating fibrosis and epithelial-to-mesenchymal transition. Mechanistic studies revealed that arsenic exposure leads to increased levels of epigenetic regulators enhancer of zeste homolog 2 (EZH2) and histone H3 lysine 27 trimethylation (H3K27me3), which were associated with the activation of inflammatory pathways, fibrosis, and impaired kidney function. Overall, our findings demonstrate that only developmental exposure to arsenic can cause dysregulation of EZH2 and H3K27me3, driving inflammation and renal fibrosis. These changes ultimately lead to chronic kidney disease in offspring, highlighting a critical window of vulnerability for arsenic toxicity with significant implications for long-term kidney health.

Epigenetic alterations and memory: key players in the development/progression of chronic kidney disease promoted by acute kidney injury and diabetes

Chronic kidney disease (CKD) is a highly prevalent global public health issue and can progress to kidney failure. Survivors of acute kidney injury (AKI) have an increased risk of progressing to CKD by 8.8-fold and kidney failure by 3.1-fold. Further, 20% to 40% of individuals with diabetes will develop CKD, also known as diabetic kidney disease (DKD). Thus, preventing these kidney diseases can positively impact quality-of-life and life-expectancy outcomes for affected individuals. Frequent episodes of hyperglycemia and renal hypoxia are implicated in the pathophysiology of CKD. Prior periods of hyperglycemia/uncontrolled diabetes can result in development/progression of DKD even after achieving normoglycemia, a phenomenon known as metabolic memory or legacy effect. Similarly, in AKI, hypoxic memory is stored in renal cells even after recovery from the initial AKI episode and can transition to CKD. Epigenetic mechanisms involving DNA methylation, chromatin histone post-translational modifications, and noncoding RNAs are implicated in both metabolic and hypoxic memory, collectively known as "epigenetic memory." This epigenetic memory is generally reversible and provides a therapeutic avenue to ameliorate persistent disease progression due to hyperglycemia and hypoxia and prevent/ameliorate CKD progression. Indeed, therapeutic strategies targeting epigenetic memory are effective at preventing CKD development/progression in experimental models of AKI and DKD. Here, we review the latest in-depth evidence for epigenetic features in DKD and AKI, and in epigenetic memories of AKI-to-CKD transition or DKD development and progression, followed by translational and clinical implications of these epigenetic changes for the treatment of these widespread kidney disorders.

Oxidative Stress in Pediatric Asthma: Sources, Mechanisms, and Therapeutic Potential of Antioxidants

Pediatric asthma is a common respiratory condition in children, characterized by a complex interplay of environmental and genetic factors. Evidence shows that the airways of stimulated asthmatic patients have increased oxidative stress, but the exact mechanisms through which this stress contributes to asthma progression are not fully understood. Oxidative stress originates from inflammatory cells in the airways, producing significant amounts of reactive oxygen species (ROS) and reactive nitrogen species (RNS). External factors such as cigarette smoke, particulate matter, and atmospheric pollutants also contribute to ROS and RNS levels. The accumulation of these reactive species disrupts the cellular redox balance, leading to heightened oxidative stress, which activates cellular signaling pathways and modulates the release of inflammatory factors, worsening asthma inflammation. Therefore, understanding the sources and impacts of oxidative stress in pediatric asthma is crucial to developing antioxidant-based treatments. This review examines the sources of oxidative stress in children with asthma, the role of oxidative stress in asthma development, and the potential of antioxidants as a therapeutic strategy for pediatric asthma.

Recent Advances in enhancer of zeste homolog 2 Inhibitors: Structural insights and therapeutic applications

Enhancer of Zeste Homolog 2 (EZH2) is overexpressed in many malignancies and plays a critical role in cancer progression. Therefore, it is considered a promising target for therapeutic intervention. Although several EZH2 inhibitors have entered clinical trials, only one has received FDA approval. In this review, we focus on the latest advancements in highly selective and potent dual-targeting EZH2 inhibitors, as well as proteolysis-targeted chimeras (PROTACs) and hydrophobic tagging (HYT) degraders. These novel compounds have been developed to address the existing gaps in the management of abnormal EZH2 expression. Notably, EZH2 inhibitors have shown great efficacy in antitumor therapy and have also demonstrated promising results in antiviral, anti-inflammatory, antisclerotic, bone protection, and nerve injury pain applications. The insights gained from this analysis could provide valuable guidance for future drug design and optimization of EZH2 inhibitors, potentially expediting the discovery of new inhibitors or degraders targeting EZH2.

Semaglutide protects against diabetes-associated cardiac inflammation via Sirt3-dependent RKIP pathway

BACKGROUND AND PURPOSE

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert cardiovascular benefits in diabetic patients, but the underlying mechanisms remain incompletely understood. Semaglutide, a novel long-acting GLP-1RA, has shown a reduced risk of cardiovascular events. Based on these results, we investigated the therapeutic potential of semaglutide in diabetic cardiomyopathy and sought to elucidate the underlying mechanisms.

EXPERIMENTAL APPROACH

Mice with diabetes induced by high-fat diet/streptozotocin were treated with semaglutide. The mechanisms underlying the cardioprotective effects of semaglutide were analysed using animal and cell experiments.

KEY RESULTS

In diabetic mice, semaglutide alleviated metabolic disorders, ameliorated myocardial fibrosis, improved cardiac function, antagonized oxidative stress and suppressed cardiomyocyte apoptosis. More significantly, semaglutide attenuated cardiac inflammation through restoring Raf kinase inhibitor protein (RKIP) expression and inhibiting downstream TANK-binding kinase 1 (TBK1)-NF-κB pathway. Meanwhile, decreased RKIP expression and activated TBK1-NF-κB signalling pathway were also found in tissues from human diabetic hearts. RKIP deficiency exacerbated cardiac inflammation and offset the cardioprotective effect of semaglutide in diabetic mice. Moreover, semaglutide also restored the expression level of Sirtuin 3(Sirt3), which served as a modulator against cardiac inflammation by regulating RKIP-dependent pathway. In diabetic mice, RKIP deficiency abolished the cardioprotective benefits conferred by the Sirt3 activator honokiol. We also found that cAMP/PKA signalling, rather than glucose lowering, contributed to the anti-inflammatory effect of semaglutide through Sirt3-dependent RKIP pathway.

CONCLUSIONS AND IMPLICATIONS

Semaglutide exerted cardioprotective effects against diabetic heart failure by alleviating cardiac inflammation through Sirt3-dependent RKIP signalling pathway.

Identification of key necroptosis-related genes and immune landscape in patients with immunoglobulin A nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is a major cause of chronic kidney disease (CKD) and kidney failure. Necroptosis is a novel type of programmed cell death that has been proved to be associated with the pathogenesis of infectious disease, cardiovascular disease, neurological disorders and so on. However, the role of necroptosis in IgAN remains unclear.

METHODS

In this study, we explored the role of necroptosis-related genes in the pathogenesis of IgAN using a comprehensive bioinformatics method. Microarray datasets GSE93798 and GSE115857 were downloaded from Gene Expression Omnibus (GEO). "limma" package of R software was employed to identify necroptosis-related differentially expressed genes (NRDEGs) between IgAN and healthy controls. GO and KEGG functional enrichment analysis was performed by Clusterprofiler. Least absolute shrinkage and selection operator (LASSO) regression analysis identified hub NRDEGs. We further established a diagnostic model consisting of 7 diagnostic hub NRDEGs and validated the efficacy by an external dataset. The expression of hub genes was confirmed in sc-RNA dataset GSE171314. Immune infiltration, gene set enrichment analysis and transcription factor binding motifs enrichment analysis were conducted to further uncover their roles.

RESULTS

1076 differentially expressed genes were identified between healthy individuals and IgAN patients from RNA-seq dataset GSE9379. Then we cross-linked them with necroptosis-related genes to obtain 9 NRDEGs. LASSO regression analysis screened out 7 hub genes (JUN, CD274, SERTAD1, NFKBIA, H19, UCHL1 and EZH2) of IgAN. We further conducted functional enrichment analysis and constructed the diagnostic model based on dataset GSE93798. GSE115857 was used as the independent validation cohort and indicated a great predictive efficacy. Immune infiltration, gene set enrichment analysis and transcription factor binding motifs enrichment analysis revealed their potential function. Finally, we screened out four drugs that were predicted to have therapeutic value of IgAN.

CONCLUSIONS

In summary, we identified 7 hub necroptosis-associated genes, which can be used as potential genetic biomarkers for IgAN prediction and treatment. Four drugs were predicted as the potential therapeutic solutions. Collectively, we provided insights into the necroptosis-related mechanisms and treatment of IgAN at the transcriptome level.

Small GTP-binding protein GDP dissociation stimulator influences cisplatin-induced acute kidney injury via PERK-dependent ER stress

Cisplatin is a common anticancer drug, but its frequent nephrotoxicity limits its clinical use. Small GTP-binding protein GDP dissociation stimulator (smgGDS), a small GTPase chaperone protein, was considerably downregulated during cisplatin-induced acute kidney injury (CDDP-AKI), especially in renal tubular epithelial cells. SmgGDS-knockdown mice was established and found that smgGDS knockdown promoted CDDP-AKI, as demonstrated by an increase in serum creatine, blood urea nitrogen levels and the appearance of tubular patterns. RNA sequencing suggested that protein kinase RNA-like ER kinase (PERK), which bridges mitochondria-associated ER membranes, was involved in smgGDS knockdown following CDDP-AKI, and then identified that smgGDS knockdown increased phosphorylated-PERK in vivo and in vitro. Furthermore, we confirmed that smgGDS deficiency aggravated apoptosis and ER stress in vivo and in vitro. And the ER stress inhibitor 4-Phenylbutyric acid and the inhibition of PERK phosphorylation mitigated smgGDS deficiency-induced ER stress related apoptosis following cisplatin treatment, while the eIF2α phosphorylation inhibitor could not reverse the smgGDS deficiency accelerated cell death. Furthermore, the over-expression of smgGDS could reverse the ER stress and apoptosis caused by CDDP. Overall, smgGDS regulated PERK-dependent ER stress and apoptosis, thereby influencing renal damage. This study identified a target for diagnosing and treating cisplatin-induced acute kidney injury.

SKLB023 protects against inflammation and apoptosis in sepsis-associated acute kidney injury via the inhibition of toll-like receptor 4 signaling

Sepsis-associated acute kidney injury (SA-AKI) is one of common critical illnesses with high morbidity and mortality. At present, effective therapeutic drugs for SA-AKI are remain lacking. SKLB023 is a synthetic small-molecule compound which exerts potent anti-inflammatory effects in our previous studies. Here, this study aimed to characterize the protective effect of SKLB023 on SA-AKI and explore its underlying mechanism. The SA-AKI experimental models have been established by cecum ligation/puncture (CLP) and lipopolysaccharide (LPS) injection in male C57BL/6J mice. SKLB023 was administered by gavage (50 or 25 mg/kg in CLP model and 50 mg/kg in LPS model) daily 3 days in advance and 30 min earlier on the day of modeling. Our results confirmed SKLB023 treatment could improve the survival of SA-AKI mice and ameliorate renal pathological injury, inflammation, and apoptosis in the two types of septic AKI mice. Mechanically, SKLB023 deceased the expression of TLR4 in LPS-triggered renal tubular epithelial cells, and inhibited the activation of downstream pathways including NF-κB and MAPK pathways. Our study suggested that SKLB023 is expected to be a potential drug for the prevention and treatment of septic AKI.

Identification and functional analysis of the hub Ferroptosis-Related gene EZH2 in diabetic kidney disease

BACKGROUND

Diabetic kidney disease (DKD) is a common microvascular complication and one of the main causes of death in diabetes. Ferroptosis, an iron-dependent mode of cell death characterized by lipid ROS accumulation, was found to be associated with a number of diseases and has great potential for kidney diseases. It has great value to identify potential ferroptosis-related genes and their biological mechanisms in DKD.

METHODS

We obtained the GSE30122 dataset from Gene Expression Omnibus (GEO) database and ferroptosis-related genes from the Ferrdb database. After differential expression analysis, and three machine learning algorithms, the hub ferroptosis-related gene EZH2 was identified. In order to investigate the function of EZH2, Gene Set Enrichment Analysis (GSEA), Gene Set Variation Analysis (GSVA) and single cell analysis were conducted. The expression of EZH2 was validated in DKD patients, HK-2 cell models and DKD mouse models. EZH2 knockdown HK-2 cells and HK-2 cells treated with GSK126 were performed to verify whether EZH2 affected ferroptosis in DKD. CHIP assay was used to detect whether EZH2 regulated ferroptosis by suppressing SLC7A11. Molecular docking was performed to explore EZH2 and four traditional Chinese medicine (Sennoside A, Berberine, Umbelliferone, Platycodin D) related to ferroptosis in DKD treatment.

RESULTS

According to the GSE30122 dataset in GEO and ferroptosis-related genes from the Ferrb database, we obtained the hub ferroptosis-related gene EZH2 in DKD via diversified machine learning methods. The increasing of EZH2 expression was shown in single cell analysis, DKD patients, DKD mouse models and high glucose induced DKD cell models. Further study showed that EZH2 knockdown and inhibition can alleviate HG-induced ferroptosis in vitro. CHIP assay showed EZH2-mediated epigenetic silencing regulated the expression of SLC7A11. Molecular docking results showed that EZH2 had strong binding stability with Sennoside A, Berberine, Umbelliferone, and Platycodin D.

CONCLUSION

Overall, our data shouwed that histone H3K27 methyltransferase EZH2 could regulate the renal tubular epithelial cell ferroptosis by suppressing SLC7A11 in DKD, which may serve as a credible reliable indicator for diagnosing DKD and a potential target for treatment.

Lonicerin alleviates ovalbumin-induced asthma of mice via inhibiting enhancer of zeste homolog 2/nuclear factor-kappa B signaling pathway

Asthma is the most common chronic disease in the respiratory system of children caused by abnormal immunity that responses to common antigens. Lonicerin exerts anti-inflammatory activity in other inflammatory models through targeting enhancer of zeste homolog 2 (EZH2) that is related to asthma. We sought to explore the role and mechanism of lonicerin in regulating allergic airway inflammation. Mice were intraperitoneally injected 10 µg ovalbumin (OVA) on postnatal day 5 (P5) and P10, and then inhaled 3% aerosolized OVA for 10 min every day on P18-20, to establish asthmatic mice model. Lonicerin (10 or 30 mg/kg) was given to mice by intragastric administration on P16-P20. Notably, the administration of lonicerin amended infiltration of inflammatory cells and mucus hypersecretion. OVA-specific IgE level, inflammatory cell count and inflammatory cytokines in asthmatic mice were reduced after lonicerin treatment. Moreover, it suppressed the activity of EZH2 and activation of nuclear factor-kappa B (NF-κB) as evidenced by decreasing tri-methylation of histone H3 at lysine 27 and reducing nuclear translocation of NF-κB p65. In a word, Lonicerin may attenuate asthma by inhibiting EZH2/NF-κB signaling pathway.

Nucleic acid and protein methylation modification in renal diseases

Although great efforts have been made to elucidate the pathological mechanisms of renal diseases and potential prevention and treatment targets that would allow us to retard kidney disease progression, we still lack specific and effective management methods. Epigenetic mechanisms are able to alter gene expression without requiring DNA mutations. Accumulating evidence suggests the critical roles of epigenetic events and processes in a variety of renal diseases, involving functionally relevant alterations in DNA methylation, histone methylation, RNA methylation, and expression of various non-coding RNAs. In this review, we highlight recent advances in the impact of methylation events (especially RNA m6A methylation, DNA methylation, and histone methylation) on renal disease progression, and their impact on treatments of renal diseases. We believe that a better understanding of methylation modification changes in kidneys may contribute to the development of novel strategies for the prevention and management of renal diseases.

TRPA1 promotes cisplatin-induced acute kidney injury via regulating the endoplasmic reticulum stress-mitochondrial damage

BACKGROUND

Cisplatin is a widely used and effective chemotherapeutic agent against cancer. However, nephrotoxicity is one of the most common side effects of cisplatin, and it can proceed to acute kidney injury (AKI). Studies have reported that activation of transient receptor potential ankyrin-1 (TRPA1) mediates cisplatin-induced renal tubular cytotoxic injury. The aim of this study was to investigate the mechanism of TRPA1 in promoting cisplatin-induced AKI through modulation of the endoplasmic reticulum stress (ERS)-mitochondrial damage.

METHODS

A cisplatin-induced HK-2 cell model in vitro and mouse model in vivo were established. The mechanism of TRPA1 promotes AKI was elucidated by H&E staining, TUNEL staining, transmission electron microscope (TEM), immunofluorescence, CCK-8 viability assays, flow cytometry, Western blotting, JC-1 assay, and enzyme linked immunosorbent assay (ELISA).

RESULT

In vivo and in vitro, HC-030031 reduced cisplatin-induced Scr and BUN level elevations; improved cisplatin-induced renal tissue injury, apoptosis, and mitochondrial dysfunction; elevated the reduced ERS-associated proteins glucose-regulated protein 78 (GRP78), glucose-regulated protein 75 (GRP75), and C/EBP homologous protein (CHOP) levels induced by cisplatin; reduced the elevated optic atrophy 1 (OPA1), mito-fusion 1 (MFN1), and mito-fusion 2 (MFN2) protein levels, and elevated phospho-dynamin-related protein 1 (p-DRP1) and mitochondrial fission factor (MFF) protein levels. HC-030031 also reduced the mitochondria-associated endoplasmic reticulum membrane (MAM) structure. In addition, TRPA1 agonists also decreased cell proliferation, increased apoptosis, and triggered mitochondrial dysfunction and calcium overload in HK-2 cells via modulation of MAM. ERS inhibitors and GRP75 inhibitors reversed these changes caused by TRPA1 agonists.

CONCLUSION

Our findings suggest that TRPA1 enhances cisplatin-induced AKI via modulation of ERS and mitochondrial damage.

Study on the Effect of EZH2 Inhibitor Combined with TIGIT Monoclonal Antibody against Multiple Myeloma Cells

EZH2, a member of the polycomb repressive complex 2, induces trimethylation of the downstream gene at the histone three lysine 27 (H3K27me3) position to inhibit tumor cell proliferation. Here, we showed that the apoptosis rate and apoptotic protein expression increased after EZH2 inhibition, whereas key molecules of the NF-κB signaling pathway and the downstream target genes were inhibited. Additionally, the expression of CD155, a TIGIT high-affinity ligand in multiple myeloma (MM) cells, was decreased by the mTOR signaling pathway. Furthermore, the combination of EZH2 inhibitor and TIGIT monoclonal antibody blockade enhanced the anti-tumor effect of natural killer cells. In summary, the EZH2 inhibitor not only plays an anti-tumor role as an epigenetic drug, but also enhances the anti-tumor effect of the TIGIT monoclonal antibody by affecting the TIGIT-CD155 axis between NK cells and MM cells, thus providing new ideas and theoretical basis for the treatment of MM patients.

Naringin abrogates angiotensin-converting enzyme (ACE) activity and podocin signalling pathway in cobalt chloride-induced nephrotoxicity and hypertension

PurposeThe persistent and alarming rates of increase in cardiovascular and renal diseases caused by chemicals such as cobalt chloride (CoCl₂) in mammalian tissues have led to the use of various drugs for the treatment of these diseases. This study aims at evaluating the nephron-protective action of Naringin (NAR), a metal-chelating antioxidant against CoCl₂-induced hypertension and nephrotoxicity.MethodsForty-two male Wistar rats were randomly distributed to seven rats of six groups and classified into Group A (Control), Group B (300 part per million; ppm CoCl₂), Group C (300 ppm CoCl₂ + 80 mg/kg NAR), Group D (300 ppm CoCl₂ + 160 mg/kg NAR), Group E (80 mg/kg NAR), and Group F (160 mg/kg NAR). NAR and CoCl₂ were administered via oral gavage for seven days. Biomarkers of renal damage, oxidative stress, antioxidant status, blood pressure parameters, immunohistochemistry of renal angiotensin-converting enzyme and podocin were determined.ResultsCobalt chloride intoxication precipitated hypertension, renal damage, and oxidative stress. Immunohistochemistry revealed higher expression of angiotensin-converting enzyme (ACE) and podocin in rats administered only CoCl₂.ConclusionTaken together, the antioxidant and metal-chelating action of Naringin administration against cobalt chloride-induced renal damage and hypertension could be through abrogation of angiotensin-converting enzyme and podocin signalling pathway.

Tubular aryl hydratocarbon receptor upregulates EZH2 to promote cellular senescence in cisplatin-induced acute kidney injury

Acute kidney injury (AKI) is one of the serious clinical syndromes with high morbidity and mortality. Despite substantial progress in understanding the mechanism of AKI, no effective drug is available for treatment or prevention. In this study, we identified that a ligand-activated transcription factor aryl hydrocarbon receptor (AhR) was abnormally increased in the kidneys of cisplatin-induced AKI mice or tubular epithelial TCMK-1 cells. The AhR inhibition by BAY2416964 and tubular conditional deletion both alleviated cisplatin-induced kidney dysfunction and tubular injury. Notably, inhibition of AhR could improve cellular senescence of injured kidneys, which was indicated by senescence-associated β-galactosidase (SA-β-gal) activity, biomarker p53, p21, p16 expression, and secretory-associated secretory phenotype IL-1β, IL-6 and TNFα level. Mechanistically, the abnormal AhR expression was positively correlated with the increase of a methyltransferase EZH2, and AhR inhibition suppressed the EZH2 expression in cisplatin-injured kidneys. Furthermore, the result of ChIP assay displayed that EZH2 might indirectly interact with AhR promoter region by affecting H3K27me3. The direct recruitment between H3K27me3 and AhR promoter is higher in the kidneys of control than that of cisplatin-treated mice, suggesting EZH2 reversely influenced AhR expression through weakening H3K27me3 transcriptional inhibition on AhR promoter. The present study implicated that AhR and EZH2 have mutual regulation, which further accelerated tubular senescence in cisplatin-induced AKI. Notably, the crucial role of AhR is potential to become a promising target for AKI.

Neoxanthin alleviates the chronic renal failure-induced aging and fibrosis by regulating inflammatory process

Chronic renal failure (CRF) refers to progressive renal damage caused by chronic kidney diseases (CKD). Dialysis therapy and kidney transplantation are the important treatment for CRF. However, due to the limitation of conditions, they cannot be widely utilized. At present, the treatment of renal failure is a worldwide problem in clinic. Therefore, in the current study, we investigated the potential therapeutic effects of neoxanthin on CFR-caused aging and fibrosis. In this work, the effects of neoxanthin on CRF were studied using experimental techniques such as biochemistry, immunohistochemistry and molecular biology. In vitro, neoxanthin alleviated the aging and oxidative damage of kidney cells. In vivo, we found that Neoxanthin could alleviate adenine-induced CRF. Neoxanthin also inhibited CRF-caused renal aging, fibrosis, oxidative stress and inflammation. These findings indicate that neoxanthin could delay the progression of CRF and alleviate CRF-induced aging and fibrosis. Collectively, we found that neoxanthin shows good potential to inhibit CRF-caused kidney aging and fibrosis, suggesting that neoxanthin may be used as a drug (or a functional food) for the treatment of CRF-related diseases.

Calycosin attenuates renal ischemia/reperfusion injury by suppressing NF-κB mediated inflammation via PPARγ/EGR1 pathway

Renal ischemia reperfusion injury (IRI) is a leading and common cause of acute kidney injury (AKI), and inflammation is a critical factor in ischemic AKI progression. Calycosin (CAL), a major active component of Radix astragali, has been reported to have anti-inflammatory effect in multiple organs. However, whether CAL can alleviate renal IRI and its mechanism remain uncertain. In the present study, a renal IRI model is established by bilateral renal pedicles occlusion for 35 min in male C57BL/6 mice, and the effect of CAL on renal IRI is measured by serum creatinine and pathohistological assay. Hypoxia/reoxygenation (H/R) stimulated human renal tubular epithelial cells HK-2 were applied to explore the regulatory mechanisms of CAL. Luciferase reporter assay and molecular docking were applied to identify the CAL's target protein and pathway. In the mice with renal IRI, CAL dose dependently alleviated the renal injury and decreased nuclear factor kappa B (NF-κB) mediated inflammatory response. Bioinformatics analysis and experiments showed that early growth response 1 (EGR1) increased in mice with renal IRI and promoted NF-κB mediated inflammatory processes, and CAL dose-dependably reduced EGR1. Through JASPAR database and luciferase reporter assay, peroxisome proliferator-activated receptor γ (PPARγ) was predicted to be a transcription factor of EGR1 and repressed the expression of EGR1 in renal tubular epithelial cells. CAL could increase PPARγ in a dose dependent manner in mice with renal IRI and molecular docking predicted CAL could bind stably to PPARγ. In HK-2 cells after H/R, CAL increased PPARγ, decreased EGR1, and inhibited NF-κB mediated inflammatory response. However, PPARγ knockdown by siRNA transfection abrogated the anti-inflammation therapeutic effect of CAL. CAL produced a protective effect on renal IRI by attenuating NF-κB mediated inflammatory response via PPARγ/EGR1 pathway.

Baicalin Alleviates Contrast-Induced Acute Kidney Injury Through ROS/NLRP3/Caspase-1/GSDMD Pathway-Mediated Proptosis in vitro

Purpose

To investigate the effect of baicalin on the reactive oxygen species (ROS)/ NOD-like receptor protein 3 (NLRP3)/Caspase-1/gasdermin-D (GSDMD) inflammasome pathway and its related mechanism in regulating pyroptosis of human renal tubular epithelial cells (HK-2) induced by contrast media.

Methods

Iohexol was used to act on HK-2 cells to establish a renal tubular cell pyroptosis model; and the signal pathway genes were silenced, cytokines were detected by enzyme-linked immunosorbent assay (ELISA), and cell viability, gene expression, and protein expression were evaluated by double fluorescence staining and flow cytometry. To assess the cytotoxicity caused by the contrast agent; cells were pretreated with different concentrations of baicalin; and then the cells were exposed to iohexol again, and the relevant indicators were tested again.

Results

After HK-2 cells were exposed to iohexol, the NLRP3 inflammasome pathway markers NLRP3, interleukin (IL)-1β, and IL-18 mRNA levels as well as the protein expression levels of NLRP3, ASC, Caspase-1, and GSDMD were up-regulated. In addition, the effect also significantly increased the IL-18, IL-1β, lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA) release, and cellular ROS levels. The results of Annexin V-FITC/PI flow cytometry showed that the level of apoptosis was increased. However, after the intervention of baicalin, the changes in the above indexes caused by iohexol stimulation of HK-2 cells were inhibited.

Conclusion

Exposure to iohexol can induce pyroptosis of HK-2 cells through the ROS/NLRP3/Caspase-1/GSDMD signaling pathway. Baicalin ameliorated iohexol-induced pyroptosis in HK-2 cells by regulating the NLRP3 inflammasome pathway.

Identification of EZH2 as Cancer Stem Cell Marker in Clear Cell Renal Cell Carcinoma and the Anti-Tumor Effect of Epigallocatechin-3-Gallate (EGCG)

The aim of the study was to develop a new therapeutic strategy to target cancer stem cells (CSCs) in clear cell renal cell carcinoma (ccRCC) and to identify typical CSC markers to improve therapy effectiveness. It was found that the corrected-mRNA expression-based stemness index was upregulated in kidney renal clear cell carcinoma (KIRC) tissues compared to non-tumor tissue and increased with higher tumor stage and grade. EZH2 was identified as a CSC marker and prognosis factor for KIRC patients. The expression of EZH2 was associated with several activated tumor-infiltrating immune cells. High expression of EZH2 was enriched in immune-related pathways, low expression was related to several metabolic pathways. Epigallocatechin-3-gallate (EGCG) was identified as the most potent suppressor of EZH2, was able to inhibit viability, migration, and invasion, and to increase the apoptosis rate of ccRCC CSCs. KIF11, VEGF, and MMP2 were identified as predictive EGCG target genes, suggesting a potential mechanism of how EZH2 might regulate invasiveness and migration. The percentages of FoxP3+ Treg cells in the peripheral blood mononuclear cells of ccRCC patients decreased significantly when cultured with spheres pretreated with EGCG plus sunitinib compared to spheres without treatment. Our findings provide new insights into the treatment options of ccRCC based on targeting CSCs.

Histone Deacetylases Cooperate with NF-κB to Support the Immediate Migratory Response after Zebrafish Pronephros Injury

Acute kidney injury (AKI) is commonly associated with severe human diseases, and often worsens the outcome in hospitalized patients. The mammalian kidney has the ability to recover spontaneously from AKI; however, little progress has been made in the development of supportive treatments. Increasing evidence suggest that histone deacetylases (HDAC) and NF-κB promote the pathogenesis of AKI, and inhibition of Hdac activity has a protective effect in murine models of AKI. However, the role of HDAC at the early stages of recovery is unknown. We used the zebrafish pronephros model to study the role of epigenetic modifiers in the immediate repair response after injury to the tubular epithelium. Using specific inhibitors, we found that the histone deacetylase Hdac2, Hdac6, and Hdac8 activities are required for the repair via collective cell migration. We found that hdac6, hdac8, and nfkbiaa expression levels were upregulated in the repairing epithelial cells shortly after injury. Depletion of hdac6, hdac8, or nfkbiaa with morpholino oligonucleotides impaired the repair process, whereas the combined depletion of all three genes synergistically suppressed the recovery process. Furthermore, time-lapse video microscopy revealed that the lamellipodia and filopodia formation in the flanking cells was strongly reduced in hdac6-depleted embryos. Our findings suggest that Hdac activity and NF-κB are synergistically required for the immediate repair response in the zebrafish pronephros model of AKI, and the timing of HDAC inhibition might be important in developing supportive protocols in the human disease.

Epigenetics-mediated pathological alternations and their potential in antiphospholipid syndrome diagnosis and therapy

APS (antiphospholipid syndrome) is a systematic autoimmune disease accompanied with venous or arterial thrombosis and poor pregnant manifestations, partly attributing to the successive elevated aPL (antiphospholipid antibodies) and provoked prothrombotic and proinflammatory molecules production. Nowadays, most researches focus on the laboratory detection and clinic features of APS, but its precise etiology remains to be deeply explored. As we all know, the dysfunction of ECs (endothelial cells), monocytes, platelets, trophoblasts and neutrophils are key contributors to APS progression. Especially, their epigenetic variations, mainly including the promoter CpGs methylation, histone PTMs (post-translational modifications) and ncRNAs (noncoding RNAs), result in genes expression or silence engaged in inflammation initiation, thrombosis formation, autoimmune activation and APOs (adverse pregnancy outcomes) in APS. Given the potential of epigenetic markers serving as diagnostic biomarkers or therapeutic targets of APS, and the encouraging advancements in epigenetic drugs are being made. In this review, we would systematically introduce the epigenetic underlying mechanisms for APS progression, comprehensively elucidate the functional mechanisms of epigenetics in boosting ECs, monocytes, platelets, trophoblasts and neutrophils. Lastly, the application of epigenetic alterations for probing novel diagnostic, specific therapeutic and prognostic strategies would be proposed.

The Role and Mechanism of Lysine Methyltransferase and Arginine Methyltransferase in Kidney Diseases

Methylation can occur in both histones and non-histones. Key lysine and arginine methyltransferases under investigation for renal disease treatment include enhancer of zeste homolog 2 (EZH2), G9a, disruptor of telomeric silencing 1-like protein (DOT1L), and protein arginine methyltransferases (PRMT) 1 and 5. Recent studies have shown that methyltransferases expression and activity are also increased in several animal models of kidney injury, such as acute kidney injury(AKI), obstructive nephropathy, diabetic nephropathy and lupus nephritis. The inhibition of most methyltransferases can attenuate kidney injury, while the role of methyltransferase in different animal models remains controversial. In this article, we summarize the role and mechanism of lysine methyltransferase and arginine methyltransferase in various kidney diseases and highlight methyltransferase as a potential therapeutic target for kidney diseases.