METTL14-regulated PI3K/Akt signaling pathway via PTEN affects HDAC5-mediated epithelial-mesenchymal transition of renal tubular cells in diabetic kidney disease

Sleeve gastrectomy links the attenuation of diabetic kidney disease to the inhibition of renal tubular ferroptosis through down-regulating TGF-β1/Smad3 signaling pathway

PURPOSE

To investigate how sleeve gastrectomy (SG), a typical operation of bariatric surgery, attenuated symptom, and progression of diabetic kidney disease (DKD).

METHODS

DKD model was induced by high-fat diet (HFD) combined with streptozocin in Wistar rats. SG was performed, and the group subjected to sham surgery served as control. The animals were euthanized 12 weeks after surgery, followed by sample collection for the subsequent experiment. The HK-2, a renal proximal tubular epithelial cell line derived from human, was utilized to investigate the potential mechanisms.

RESULTS

SG improved metabolic parameters and glucose homeostasis, and could alleviate DKD in terms of renal function indices as well as histological and morphological structures in DM rats, accompanied with a significant reduction in renal tubular injury. Compared with sham group, SG reduced the renal tubular ferroptosis. To further clarify the mechanism involved, in vitro experiments were performed. In the presence of high glucose, renal tubular TGF-β1 secretion was significantly increased in HK-2 cell line, which led to activation of ferroptosis through TGF-β1/Smad3 signaling pathway. Inhibition of TGF-β1 receptor and phosphorylation of Smad3 significantly ameliorated TGF-β1-mediated ferroptosis. In vivo experiments also found that SG improved the hyperglycemic environment, reduced renal TGF-β1 concentrations, and down-regulated the TGF-β1/Smad3 signaling pathway.

CONCLUSIONS

With the capacity to lower the glucose, SG could attenuate the ferroptosis by inhibiting TGF-β1/Smad3 signaling pathway in DKD rats, and eventually attenuated DKD.

Revealing the potential role of hsa-miR-663a in modulating the PI3K-Akt signaling pathway via miRNA microarray in spinal muscular atrophy patient fibroblast-derived iPSCs

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder due to deletion or mutation of survival motor neuron 1 (SMN1) gene. Although survival motor neuron 2 (SMN2) gene is still present in SMA patients, the production of full-length survival motor neuron (SMN) protein is insufficient owing to missing or mutated SMN1. No current disease-modifying therapies can cure SMA. The aim of this study was to explore microRNA (miRNA)-based therapies that may serve as a potential target for therapeutic intervention in delaying SMA progression or as treatment. The study screened for potentially dysregulated miRNAs in SMA fibroblast-derived iPSCs using miRNA microarray. Results from the miRNA microarray were validated using quantitative reverse transcription polymerase chain reaction. Bioinformatics analysis using various databases was performed to predict the potential putative gene targeted by hsa-miR-663a. The findings showed differential expression of hsa-miR-663a in SMA patients in relation to a healthy control. Bioinformatics analysis identified GNG7, IGF2, and TNN genes that were targeted by hsa-miR-663a to be involved in the PI3K-AKT pathway, which may be associated with disease progression in SMA. Thus, this study suggests the potential role of hsa-miR-663a as therapeutic target for the treatment of SMA patients in the near future.

Methyltransferase like-14 suppresses growth and metastasis of non-small-cell lung cancer by decreasing LINC02747

Multiple epigenetic regulatory mechanisms exert critical roles in tumor development, and understanding the interactions and impact of diverse epigenetic modifications on gene expression in cancer is crucial for the development of precision medicine. We found that methyltransferase-like 14 (METTL14) was significantly downregulated in non-small-cell lung cancer (NSCLC) tissues. Functional experiments demonstrated that overexpression of METTL14 inhibited the proliferation and migration of NSCLC cells both in vivo and in vitro, and the colorimetric m6A quantification assay also showed that knockdown of METTL14 notably reduced global m6A modification levels in NSCLC cells. By using the methylated-RNA immunoprecipitation-qPCR and dual-luciferase reporter assays, we verified that long noncoding RNA LINC02747 was a target of METTL14 and was regulated by METTL14-mediated m6A modification, and silencing LINC02747 inhibited the malignant progression of NSCLC by modulating the PI3K/Akt and CDK4/Cyclin D1 signaling pathway. Further studies revealed that overexpression of METTL14 promoted m6A methylation and accelerated the decay of LINC02747 mRNA via increased recognition of the "GAACU" binding site by YTHDC2. Additionally, histone demethylase lysine-specific histone demethylase 5B (KDM5B) mediated the demethylation of histone H3 lysine 4 tri-methylation (H3K4me3) in the METTL14 promoter region and repressed its transcription. In summary, KDM5B downregulated METTL14 expression at the transcriptional level in a H3K4me3-dependent manner, while METTL14 modulated LINC02747 expression via m6A modification. Our results demonstrate a synergy of multiple mechanisms in regulating the malignant phenotype of NSCLC, revealing the complex regulation involved in the occurrence and development of cancer.

Sodium arsenite induces hepatic stellate cells activation by m6A modification of TGF-β1 during liver fibrosis

The compound known as Sodium arsenite (NaAsO2), which is a prevalent type of inorganic arsenic found in the environment, has been strongly associated with liver fibrosis (LF), a key characteristic of nonalcoholic fatty liver disease (NAFLD), which has been demonstrated in our previous study. Our previous research has shown that exposure to NaAsO2 triggers the activation of hepatic stellate cells (HSCs), a crucial event in the development of LF. However, the molecular mechanism is still unknown. N6-methyladenosine (m6A) modification is the most crucial post-transcriptional modification in liver disease. Nevertheless, the precise function of m6A alteration in triggering HSCs and initiating LF caused by NaAsO2 remains unknown. Here, we found that NaAsO2 induced LF and HSCs activation through TGF-β/Smad signaling, which could be reversed by TGF-β1 knockdown. Furthermore, NaAsO2 treatment enhanced the m6A modification level both in vivo and in vitro. Significantly, NaAsO2 promoted the specific interaction of METTL14 and IGF2BP2 with TGF-β1 and enhanced the TGF-β1 mRNA stability. Notably, NaAsO2-induced TGF-β/Smad pathway and HSC-t6 cells activation might be avoided by limiting METTL14/IGF2BP2-mediated m6A modification. Our findings showed that the NaAsO2-induced activation of HSCs and LF is made possible by the METTL14/IGF2BP2-mediated m6A methylation of TGF-β1, which may open up new therapeutic options for LF brought on by environmental hazards.

Landscape of transcriptome-wide m6A modification in diabetic liver reveals rewiring of PI3K-Akt signaling after physical exercise

AIM

Type 2 diabetes mellitus (T2DM) is one of the most common diseases, and epigenetic modification N6-methyladenosine (m6A) is essential for transcriptional modulation involved in its development. However, the precise role and landscape of transcriptome-wide m6A alterations in molecular adaptations after physical exercise have yet to be fully elucidated.

METHODS

Four-week-old male C57BL/6J mice received a high-fat diet (HFD) for 12 weeks to establish a diabetic state, and HFD mice were simultaneously subjected to physical exercise (HFD + EX). The hepatic RNA m6A methylome was examined, the conjoint MeRIP-seq and RNA-seq was performed, and the exercise-modulated genes were confirmed.

RESULTS

Physical exercise significantly ameliorates liver metabolic disorder and triggers a dynamic change in hepatic RNA m6A. By analyzing the distribution of m6A in transcriptomes, an abundance of m6A throughout mRNA transcripts and a pattern of conserved m6A after physical exercise was identified. It is noteworthy that conjoint MeRIP-seq and RNA-seq data revealed that both differentially methylated genes and differentially expressed genes were enriched in all stages of the PI3K-Akt signaling pathway, in particular the upstream nodes of this pathway, which are considered a valuable therapeutic target for T2DM. Moreover, in vivo and in vitro analyses showed that exercise-mediated methyltransferase Rbm15 positively regulated the expression of two upstream genes (Itga3 and Fgf21) in an m6A-dependent manner.

CONCLUSION

These findings highlight the pivotal role of the exercise-induced m6A epigenetic network and contribute insights into the intricate epigenetic mechanism underlying insulin signaling.

GRP78 Contributes to the Beneficial Effects of SGLT2 Inhibitor on Proximal Tubular Cells in DKD

The beneficial effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors on kidney function are well-known; however, their molecular mechanisms are not fully understood. We focused on 78-kDa glucose-regulated protein (GRP78) and its interaction with SGLT2 and integrin-β1 beyond the chaperone property of GRP78. In streptozotocin (STZ)-induced diabetic mouse kidneys, GRP78, SGLT2, and integrin-β1 increased in the plasma membrane fraction, while they were suppressed by canagliflozin. The altered subcellular localization of GRP78/integrin-β1 in STZ mice promoted epithelial mesenchymal transition (EMT) and fibrosis, which were mitigated by canagliflozin. High-glucose conditions reduced intracellular GRP78, increased its secretion, and caused EMT-like changes in cultured HK2 cells, which were again inhibited by canagliflozin. Urinary GRP78 increased in STZ mice, and in vitro experiments with recombinant GRP78 suggested that inflammation spread to surrounding tubular cells and that canagliflozin reversed this effect. Under normal glucose culture, canagliflozin maintained sarco/endoplasmic reticulum (ER) Ca2+-ATPase (SERCA) activity, promoted ER robustness, reduced ER stress response impairment, and protected proximal tubular cells. In conclusion, canagliflozin restored subcellular localization of GRP78, SGLT2, and integrin-β1 and inhibited EMT and fibrosis in DKD. In nondiabetic chronic kidney disease, canagliflozin promoted ER robustness by maintaining SERCA activity and preventing ER stress response failure, and it contributed to tubular protection.

ARTICLE HIGHLIGHTS

Diabetes and diabetic associative diseases: An overview of epigenetic regulations of TUG1

The epigenetic regulation of lncRNA TUG1 has garnered significant attention in the context of diabetes and its associated disorders. TUG1's multifaceted roles in gene expression modulation, and cellular differentiation, and it plays a major role in the growth of diabetes and the issues that are related to it due to pathological processes. In diabetes, aberrant epigenetic modifications can lead to dysregulation of TUG1 expression, contributing to disrupted insulin signaling, impaired glucose metabolism, and beta-cell dysfunction. Moreover, it has been reported that TUG1 contributes to the development of problems linked to diabetes, such as nephropathy, retinopathy, and cardiovascular complications, through epigenetically mediated mechanisms. Understanding the epigenetic regulations of TUG1 offers novel insights into the primary molecular mechanisms of diabetes and provides a possible path for healing interventions. Targeting epigenetic modifications associated with TUG1 holds promise for restoring proper gene expression patterns, ameliorating insulin sensitivity, and mitigating the inception and development of diabetic associative diseases. This review highlights the intricate epigenetic landscape that governs TUG1 expression in diabetes, encompassing DNA methylation and alterations in histone structure, as well as microRNA interactions.

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.

Roles of Sirt1 and its modulators in diabetic microangiopathy: A review

Diabetic vascular complications include diabetic macroangiopathy and diabetic microangiopathy. Diabetic microangiopathy is characterised by impaired microvascular endothelial function, basement membrane thickening, and microthrombosis, which may promote renal, ocular, cardiac, and peripheral system damage in diabetic patients. Therefore, new preventive and therapeutic strategies are urgently required. Sirt1, a member of the nicotinamide adenine dinucleotide-dependent histone deacetylase class III family, regulates different organ growth and development, oxidative stress, mitochondrial function, metabolism, inflammation, and aging. Sirt1 is downregulated in vascular injury and microangiopathy. Moreover, its expression and distribution in different organs correlate with age and play critical regulatory roles in oxidative stress and inflammation. This review introduces the background of diabetic microangiopathy and the main functions of Sirt1. Then, the relationship between Sirt1 and different diabetic microangiopathies and the regulatory roles mediated by different cells are described. Finally, we summarize the modulators that target Sirt1 to ameliorate diabetic microangiopathy as an essential preventive and therapeutic measure for diabetic microangiopathy. In conclusion, targeting Sirt1 may be a new therapeutic strategy for diabetic microangiopathy.

Microbial imidazole propionate affects glomerular filtration rate in patients with diabetic nephropathy through association with HSP90α

Imidazole propionate (ImP) is a detrimental metabolite produced by the fermentation of histidine intermediates via the intestinal flora. Here, the untargeted metabolite analysis of plasma metabolites from patients with diabetic nephropathy (DN), in combination with the Human Metabolome Database, revealed significantly increased levels of ImP in patients with DN, with a positive correlation with patients' blood creatinine concentration and urinary albumin-to-creatinine ratio, and a negative correlation with the glomerular filtration rate. RNA-seq was applied to detect the effects of ImP on renal tissue transcriptome in mice with DN. It demonstrated that ImP exacerbated renal injury in mice with DN and promoted renal tubular epithelial-mesenchymal transition (EMT), leading to renal mesenchymal fibrosis and renal impairment. Furthermore, ImP was found to directly target HAP90α and activate the PI3K-Akt signalling pathway, which is involved in EMT, by the drug affinity response target stability method. The findings showed that ImP may provide a novel target for DN quality, as it can directly bind to and activate HSP90, thereby facilitating the development of DN while acting as a potential indicator for the clinical diagnosis of DN.

The role of PI3K/Akt signaling pathway in chronic kidney disease

Chronic kidney disease (CKD), including chronic glomerulonephritis, IgA nephropathy and diabetic nephropathy, are common chronic diseases characterized by structural damage and functional decline of the kidneys. The current treatment of CKD is symptom relief. Several studies have reported that the phosphatidylinositol 3 kinases (PI3K)/protein kinase B (Akt) signaling pathway is a pathway closely related to the pathological process of CKD. It can ameliorate kidney damage by inhibiting this signal pathway which is involved with inflammation, oxidative stress, cell apoptosis, epithelial mesenchymal transformation (EMT) and autophagy. This review highlights the role of activating or inhibiting the PI3K/Akt signaling pathway in CKD-induced inflammatory response, apoptosis, autophagy and EMT. We also summarize the latest evidence on treating CKD by targeting the PI3K/Akt pathway, discuss the shortcomings and deficiencies of PI3K/Akt research in the field of CKD, and identify potential challenges in developing these clinical therapeutic CKD strategies, and provide appropriate solutions.

Causality between allergic diseases and kidney diseases: a two-sample Mendelian randomization study

Background

Evidence from observational studies and clinical trials suggests that the allergic diseases (ADs) are associated with kidney diseases (KDs). However, the causal association between them remains to be determined. We used bidirectional two-sample Mendelian randomization (MR) analysis to evaluate the potential causality between them.

Methods

Mendelian randomization (MR) was performed using publicly available genome-wide association study (GWAS) summary datasets. Inverse variance weighted (IVW), weighted median, MR-Egger regression, simple mode, and weighted mode methods are used to evaluate the causality between ADs and KDs. Sensitivity and heterogeneity analyses were used to ensure the stability of the results.

Results

The MR results indicated that genetic susceptibility to ADs was associated with a higher risk of CKD [odds ratio (OR) = 1.124, 95% CI = 1.020-1.239, p = 0.019] and unspecified kidney failure (OR = 1.170, 95% CI = 1.004-1.363, p = 0.045) but not with kidney stone, ureter stone or bladder stone (OR = 1.001, 95% CI = 1.000-1.002, p = 0.216), other renal or kidney problem (OR = 1.000, 95% CI = 1.000-1.001, p = 0.339), urinary tract or kidney infection (OR = 1.000, 95% CI = 0.999-1.001, p = 0.604), kidney volume (OR = 0.996, 95% CI = 0.960-1.033, p = 0.812) and cyst of kidney (OR = 0.914, 95% CI = 0.756-1.105, p = 0.354). No causal evidence of KDs on ADs was found in present study.

Conclusion

Results from MR analysis indicate a causal association between ADs and CKD and unspecified kidney failure. These findings partly suggest that early monitoring of CKD risk in patients with ADs is intentional.

METTL3/YTHDF2 m6A axis mediates the progression of diabetic nephropathy through epigenetically suppressing PINK1 and mitophagy

AIMS

This research aimed to investigate the specific mechanism of methyltransferase like 3 (METTL3) in the progression of diabetic kidney disease (DKD).

MATERIALS AND METHODS

The model of diabetic kidney disease was established with HK-2 cells and mice in vitro and in vivo. The N6 methyladenosine (m6A) contents in the cells and tissues were detected with a commercial kit and the m6A levels of PTEN induced putative kinase 1 (PINK2) were detected with a MeRIP kit. The mRNA and protein levels were determined with RT-qPCR and western blot. The ROS, TNF-α, and IL-6 levels were assessed with ELISA. The cell proliferative ability was measured by a CCK-8 assay and cell apoptosis was determined with TUNEL staining. The HE and Masson staining was performed to observe the renal morphology. The RIP assay was conducted to detect the interaction between METTL3/YTHDF2 and PINK1.

RESULTS

The m6A content and METTL3 levels were prominently elevated in diabetic kidney disease. METTL3 silencing promoted the cell growth and the expression of LC3 II, PINK1, and Parkin, while inhibiting the cell apoptosis and the expression of LC3 I and p62 in the high glucose (HG) stimulated HK-2 cells. METTL3 silencing also decreased the ROS, TNF-α, and IL-6 levels in diabetic kidney disease. PINK1 silencing neutralized the function of sh-METTL3 in the HG stimulated HK-2 cells. The HE and Masson staining showed that METTL3 silencing alleviated the kidney injury induced by DKD. METTL3 silencing decreased the m6A levels of PINK1, while increased the mRNA levels of PINK1 which depended on YTHDF2.

CONCLUSIONS

METTL3 silencing could inhibit the progression of diabetic nephropathy in vivo and in vitro by regulating the m6A modification of PINK1, which depends on YTHDF2. Our research lays the theoretical foundation for the precise treatment of diabetic kidney disease and the development of targeted drugs in the future.

Targeting the m6A RNA methyltransferase METTL3 attenuates the development of kidney fibrosis

Kidney fibrosis is a major mechanism underlying chronic kidney disease (CKD). N6-methyladenosine (m6A) RNA methylation is associated with organ fibrosis. We investigated m6A profile alterations and the inhibitory effect of RNA methylation in kidney fibrosis in vitro (TGF-β-treated HK-2 cells) and in vivo (unilateral ureteral obstruction [UUO] mouse model). METTL3-mediated signaling was inhibited using siRNA in vitro or the METTL3-specific inhibitor STM2457 in vivo and in vitro. In HK-2 cells, METTL3 protein levels increased in a dose- and time-dependent manner along with an increase in the cellular m6A levels. In the UUO model, METTL3 expression and m6A levels were significantly increased. Transcriptomic and m6A profiling demonstrated that epithelial-to-mesenchymal transition- and inflammation-related pathways were significantly associated with RNA m6A methylation. Genetic and pharmacologic inhibition of METTL3 in HK-2 cells decreased TGF-β-induced fibrotic marker expression. STM2457-induced inhibition of METTL3 attenuated the degree of kidney fibrosis in vivo. Furthermore, METTL3 protein expression was significantly increased in the tissues of CKD patients with diabetic or IgA nephropathy. Therefore, targeting alterations in RNA methylation could be a potential therapeutic strategy for treating kidney fibrosis.

GRK5 promoted renal fibrosis via HDAC5/Smad3 signaling pathway

Renal fibrosis is a common pathological feature of chronic kidney diseases (CKD), poses a significant burden in the aging population, and is a major cause of end-stage renal disease (ESRD). In this study, we investigated the role of G protein-coupled receptor kinases (GRKs) 5 in the pathogenesis of renal fibrosis. GRK5 is a serine/threonine kinase that regulates G protein-coupled receptor (GPCR) signaling. GRK5 has been shown to play a role in various diseases including cardiac disorders and cancer. However, the role of GRK5 in renal fibrosis remains largely unknown. Our finding revealed that GRK5 was significantly overexpressed in renal fibrosis. Specifically, GRK5 was transferred into the nucleus via its nuclear localization sequence to regulate histone deacetylases (HDAC) 5 expression under renal fibrosis. GRK5 acted as an upstream regulator of HDAC5/Smad3 signaling pathway. HDAC5 regulated and prevented the transcriptional activity of myocyte enhancer factor 2A (MEF2A) to repress the transcription of Smad7 which leading to the activation of Smad3. These findings first revealed that GRK5 may be a potential therapeutic target for the treatment of renal fibrosis. Inhibition of GRK5 activity may be a promising strategy to attenuate the progression of renal fibrosis.

SMAD4 inhibits glycolysis in ovarian cancer through PI3K/AKT/HK2 signaling pathway by activating ARHGAP10

BACKGROUND

ARHGAP10 is a tumor-suppressor gene related to ovarian cancer (OC) progression; however, its specific mechanism is unclear.

AIMS

To investigate the effect of ARHGAP10 on OC cell migration, invasion, and glycolysis.

METHODS AND RESULTS

Quantitative real-time PCR (qRT-PCR) quantified mRNA and protein expressions of AKT, p-AKT, HK2, and SMAD4 were tested by Western blot. EdU, Wound healing, and Transwell assay were utilized to evaluate OC cell proliferation, migration, and invasion. We used a Seahorse XF24 Extracellular Flux Analyzer to monitor cellular oxygen consumption rates (OCR) and extracellular acidification rates (ECAR). Chromatin immunoprecipitation (ChIP) was used to analyze the transcriptional regulation of ARHGAP10 by SMAD4. ARHGAP10 expression in OC tissues was detected by immunohistochemistry. Our results showed that ARHGAP10 expression was negatively related to lactate levels in human OC tissues. ARHGAP10 overexpression can inhibit the migration, proliferation, and invasion of OC cells, and this function can be blocked by 2-Deoxy-D-glucose. Moreover, we found that ARHGAP10 expression can be rescued with the AKT inhibitor LY294002.

CONCLUSIONS

This study revealed that the antitumor effects of ARHGAP10 in vivo and in vitro possibly suppress oncogenic glycolysis through the PI3K/AKT/HK2-regulated glycolysis metabolism pathway.

Multi-omics analysis reveals the potential pathogenesis and therapeutic targets of diabetic kidney disease

Clinicians have long been interested in understanding the molecular basis of diabetic kidney disease (DKD)and its potential treatment targets. Its pathophysiology involves protein phosphorylation, one of the most recognizable post-transcriptional modifications, that can take part in many cellular functions and control different metabolic processes. In order to recognize the molecular and protein changes of DKD kidney, this study applied Tandem liquid chromatography-mass spectrometry (LC-MS/MS) and Next-Generation Sequencing, along with Tandem Mass Tags (TMT) labeling techniques to evaluate the mRNA, protein and modified phosphorylation sites between DKD mice and model ones. Based on Gene Ontology (GO) and KEGG pathway analyses of transcriptome and proteome, The molecular changes of DKD include accumulation of extracellular matrix, abnormally activated inflammatory microenvironment, oxidative stress and lipid metabolism disorders, leading to glomerulosclerosis and tubulointerstitial fibrosis. Oxidative stress has been emphasized as an important factor in DKD and progression to ESKD, which is directly related to podocyte injury, albuminuria and renal tubulointerstitial fibrosis. A histological study of phosphorylation further revealed that kinases were crucial. Three groups of studies have found that RAS signaling pathway, RAP1 signaling pathway, AMPK signaling pathway, PPAR signaling pathway and HIF-1 signaling pathway were crucial for the pathogenesis of DKD. Through this approach, it was discovered that targeting specific molecules, proteins, kinases and critical pathways could be a promising approach for treating DKD.

Emerging role of N6-methyladenosine in the homeostasis of glucose metabolism

N6-methyladenosine (m6A) is the most prevalent post-transcriptional internal RNA modification, which is involved in the regulation of diverse physiological processes. Dynamic and reversible m6A modification has been shown to regulate glucose metabolism, and dysregulation of m6A modification contributes to glucose metabolic disorders in multiple organs and tissues including the pancreas, liver, adipose tissue, skeletal muscle, kidney, blood vessels, and so forth. In this review, the role and molecular mechanism of m6A modification in the regulation of glucose metabolism were summarized, the potential therapeutic strategies that improve glucose metabolism by targeting m6A modifiers were outlined, and feasible directions of future research in this field were discussed as well, providing clues for translational research on combating metabolic diseases based on m6A modification in the future.

Gualou xiebai decoction ameliorates cardiorenal syndrome type II by regulation of PI3K/AKT/NF-κB signalling pathway

BACKGROUND

Cardiorenal syndromes type II (CRS2) is a multi-organ ailment that manifests as a combination of cardiac and renal dysfunction, resulting in chronic kidney disease due to chronic cardiac insufficiency. It affects at least 26 million people worldwide, and its prevalence is increasing. Gualou Xiebai Decoction (GXD), a traditional Chinese medicine (TCM) with a rich history of application in the management of coronary artery disease, has been explored for its potential therapeutic benefits in CRS2. Nevertheless, the mechanism by which GXD alleviates CRS2 remains obscure, necessitating further investigation.

PURPOSE

The aim of this study was to assess the effects of the ethanolic extract of GXD on CRS2 and to elucidate the underlying mechanism in a rat model of myocardial infarction, offering a potential target for clinical treatment for CRS2.

STUDY DESIGN AND METHODS

A rat model of CRS2 was induced by surgical myocardial infarction and treated with GXD for 10 weeks. Cardiac function was assessed using echocardiography, while serum and urine biochemistry were analyzed to evaluate potential cardiac and renal damage. Furthermore, tissue samples were obtained for histological, protein, and genetic investigations. In addition, network pharmacology analysis and molecular docking were utilized to predict the primary active compounds, potential therapeutic targets, and interventional pathways through which GXD could potentially exert its effects on CRS2. Subsequently, these predictions were confirmed in vivo and vitro through various analyses.

RESULTS

The current investigation employed echocardiography to exhibit the apparent cardiac remodeling following the induction of myocardial infarction. Damage to the heart and kidneys of CRS2 rats was effectively ameliorated by administration of GXD. The outcomes derived from the analyses of HE and Masson staining indicated that the pathological damage to the heart and kidney tissues of rats in the GXD groups was considerably alleviated. Using network pharmacology analysis, AKT1, IL-6, and TNF-α were identified as plausible therapeutic targets for the treatment of CRS with GXD. Subsequent functional and pathway enrichment analysis of the underlying targets disclosed that the PI3K/AKT/NF-κB signaling pathway may be involved in the mechanism of GXD in the treatment of CRS2. Immunohistochemical, western blot, RT-PCR and immunofluorescence staining were employed to demonstrate that GXD can regulate the PI3K/AKT/NF-κB signaling pathway in the CRS2 rat model. Ultimately, administration of the PI3K/AKT agonist 740Y-P counteracted the effect of diosmetin, which was one of the potential active components of GXD analysed by compound-target-disease network, on p-PI3K and p-AKT in vitro.

CONCLUSIONS

The findings of this study suggest that GXD improves cardiac and renal function in CRS2 rats and that the underlying mechanism involves inhibition of the PI3K/AKT/NF-κB pathway.

Identification and validation of voltage-dependent anion channel 1-related genes and immune cell infiltration in diabetic nephropathy

AIMS/INTRODUCTION

This study investigated the roles of voltage-dependent anion channel 1-related differentially expressed genes (VRDEGs) in diabetic nephropathy (DN).

MATERIALS AND METHODS

We downloaded two datasets from patients with DN, namely, GSE30122 and GSE30529, from the Gene Expression Omnibus database. VRDEGs associated with DN were obtained from the intersection of voltage-dependent anion channel 1-related genes from the GeneCards database, and differentially expressed genes were screened according to group (DN/healthy) in the two datasets. The enriched pathways of the VRDEGs were analyzed. Hub genes were selected using a protein-protein interaction network, and their predictive value was verified through receiver operating characteristic curve analysis. The CIBERSORTx software examined hub genes and immune cell infiltration associations. The protein expression of hub genes was verified through immunohistochemistry in 16-week-old db/db mice for experimentation as a model of type 2 DN. Finally, potential drugs targeting hub genes that inhibit DN development were identified.

RESULTS

A total of 57 VRDEGs were identified. The two datasets showed high expression of the PI3K, Notch, transforming growth factor-β, interleukin-10 and interleukin-17 pathways in DN. Five hub genes (ITGAM, B2M, LYZ, C3 and CASP1) associated with DN were identified and verified. Immunohistochemistry showed that the five hub genes were highly expressed in db/db mice, compared with db/m mice. The infiltration of immune cells was significantly correlated with the five hub genes.

CONCLUSIONS

Five hub genes were significantly correlated with immune cell infiltration and might be crucial to DN development. This study provides insight into the mechanisms involved in the pathogenesis of DN.

The involvement of MALAT1-ALKBH5 signaling axis into proliferation and metastasis of human papillomavirus-positive cervical cancer

Infection with high-risk human papillomavirus (HPV), for example, with types 16 and 18, is closely associated with cervical cancer development, which continues to threaten women's health globally. Although HPV oncogenes have been recognized as the main cause of transformation of normal cervical epithelial cells, non-coding RNA could also be involved in the initiation and promotion of cervical cancer development. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a well-documented long non-coding RNA (lncRNA), has been previously reported to exert roles in HPV-positive cervical cancer; however, the detailed underlying mechanism has yet to be investigated. In the present study, high expression levels of MALAT1 in HPV-Positive Cervical Cancer cells were confirmed, and silencing MALAT1 resulted in decreased rates of cell proliferation, migration, and invasion, both in vitro and in a zebrafish xenograft tumor model. Moreover, the results obtained showed that silencing MALAT1 led to down-regulation of the N6-methyladenosine (m6A) demethylase ALKBH5 via regulating miR-141-3p expression, which caused a decrease in the expression levels of matrix metalloproteinase 2 (MMP2) and MMP9 expression, thereby suppressing cell migration and invasion. Taken together, the results obtained have suggested that the MALAT-ALKBH5 signaling axis may be activated in HPV-positive cervical cancer cells, which could contribute to cell proliferation and metastasis through the regulation of key genes, such as MMP2 or MMP9. The findings of the present study should both help to improve our understanding of the underlying tumorigenic mechanisms of HPV-positive cervical cancer and be of further use in the development of potential therapeutic drugs.

Lactiplantibacillus plantarum NKK20 Increases Intestinal Butyrate Production and Inhibits Type 2 Diabetic Kidney Injury through PI3K/Akt Pathway

Nephropathy injury is a prevalent complication observed in individuals with diabetes, serving as a prominent contributor to end-stage renal disease, and the advanced glycation products (AGEs) are important factors that induce kidney injury in patients with diabetes. Addressing this condition remains a challenging aspect in clinical practice. The aim of this study was to explore the effects of Lactiplantibacillus plantarum NKK20 strain (NKK20) which protects against diabetic kidney disease (DKD) based on animal and cell models. The results showed that the NKK20 can significantly reduce renal inflammatory response, serum oxidative stress response, and AGE concentration in diabetic mice. After treatment with NKK20, the kidney damage of diabetic mice was significantly improved, and more importantly, the concentration of butyrate, a specific anti-inflammatory metabolite of intestinal flora in the stool of diabetic mice, was significantly increased. In addition, nontargeted metabolomics analysis showed a significant difference between the metabolites in the mouse serum contents of the NKK20 administration group and those in the nephropathy injury group, in which a total of 24 different metabolites that were significantly affected by NKK20 were observed, and these metabolites were mainly involved in glycerophospholipid metabolism and arachidonic acid metabolism. Also, the administration of butyrate to human kidney- (HK-) 2 cells that were stimulated by AGEs resulted in a significant upregulation of ZO-1, Occludin, and E-cadherin gene expressions and downregulation of α-SMA gene expression. This means that butyrate can maintain the tight junction structure of HK-2 cells and inhibit fibrosis. Butyrate also significantly inhibited the activation of PI3K/Akt pathway. These results indicate that NKK20 can treat kidney injury in diabetic mice by reducing blood glucose and AGE concentration and increasing butyrate production in the intestine. By inhibiting PI3K pathway activation in HK-2 cells, butyrate maintains a tight junction structure of renal tubule epithelial cells and inhibits renal tissue fibrosis. These results suggest that NKK20 is helpful to prevent and treat the occurrence and aggravation of diabetic kidney injury.

Unveiling FOS as a Potential Diagnostic Biomarker and Emetine as a Prospective Therapeutic Agent for Diabetic Nephropathy

Background

Diabetic nephropathy (DN) is one of the primary causes of end-stage renal disease, yet effective therapeutic targets remain elusive. This study aims to identify novel diagnostic biomarkers and potential therapeutic candidates for DN.

Methods

Differentially expressed genes (DEGs) in GSE96804 and GSE142025 were identified and functional enrichment analysis was performed. Diagnostic biomarkers were selected using machine learning algorithms and evaluated by Receiver Operating Characteristic analysis. c-Fos expression was validated in an established DN mouse model. Immune infiltration levels were assessed with Single-Sample Gene Set Enrichment Analysis. Co-expression analysis revealed regulatory relationships involving FOS. cMAP predicted potential therapeutic candidates. Transcriptome sequencing and experiments in RAW264.7 cells was performed to investigate molecular mechanisms of emetine.

Results

In both datasets, we identified 44 upregulated and 74 downregulated DEGs involved in focal adhesion, ECM-receptor interaction, and the PI3K-Akt signaling pathway. FOS emerged as a robust diagnostic marker with decreased expression in DN patients and DN mouse. Co-expression analysis revealed potential regulatory mechanisms of FOS, implicating the MAPK signaling pathway, regulation of cell proliferation and apoptotic signaling pathways. Immune dysregulation was observed in DN patients. Notably, emetine was identified as a potential therapeutic candidate. Transcriptome sequencing and experimental validation demonstrated emetine suppressed M1 macrophage polarization by inhibiting the activation of NF-κB signaling pathway, as well as reducing the expression of Il-18 and Ccl5.

Conclusion

In conclusion, our study identified FOS as a promising diagnostic biomarker and emetine as a potential therapeutic candidate for DN. These findings enhance our understanding of DN pathogenesis and present novel prospects for therapeutic strategies.

The role of N-methyladenosine modification in acute and chronic kidney diseases

N6-methyladenosine (m6A) modification is a kind of RNA modification in which methylation occurs at the sixth N position in adenosine in RNA, which can occur in various RNAs such as mRNAs, lncRNAs and miRNAs. This is one of the most prominent and frequent posttranscriptional modifications within organisms and has been shown to function dynamically and reversibly in a variety of ways, including splicing, export, attenuation and translation initiation efficiency to regulate RNA expression. There are three main enzymes associated with m6A modification: writers, readers and erasers. Increasing evidence has shown that m6A modification is associated with the onset and development of kidney disease. In this article, we address the important physiological and pathological roles of m6A modification in kidney diseases (uremia, ischemia-reperfusion kidney injury, drug-induced kidney injury, and diabetic nephropathy) and its molecular mechanisms to provide reference for the diagnosis and clinical management of kidney diseases.

N6-methyladenosine (m6A) methylation in kidney diseases: Mechanisms and therapeutic potential

The N6-methyladenosine (m6A) modification is regulated by methylases, commonly referred to as "writers," and demethylases, known as "erasers," leading to a dynamic and reversible process. Changes in m6A levels have been implicated in a wide range of cellular processes, including nuclear RNA export, mRNA metabolism, protein translation, and RNA splicing, establishing a strong correlation with various diseases. Both physiologically and pathologically, m6A methylation plays a critical role in the initiation and progression of kidney disease. The methylation of m6A may also facilitate the early diagnosis and treatment of kidney diseases, according to accumulating research. This review aims to provide a comprehensive overview of the potential role and mechanism of m6A methylation in kidney diseases, as well as its potential application in the treatment of such diseases. There will be a thorough examination of m6A methylation mechanisms, paying particular attention to the interplay between m6A writers, m6A erasers, and m6A readers. Furthermore, this paper will elucidate the interplay between various kidney diseases and m6A methylation, summarize the expression patterns of m6A in pathological kidney tissues, and discuss the potential therapeutic benefits of targeting m6A in the context of kidney diseases.

Pathomechanisms of Diabetic Kidney Disease

The worldwide occurrence of diabetic kidney disease (DKD) is swiftly rising, primarily attributed to the growing population of individuals affected by type 2 diabetes. This surge has been transformed into a substantial global concern, placing additional strain on healthcare systems already grappling with significant demands. The pathogenesis of DKD is intricate, originating with hyperglycemia, which triggers various mechanisms and pathways: metabolic, hemodynamic, inflammatory, and fibrotic which ultimately lead to renal damage. Within each pathway, several mediators contribute to the development of renal structural and functional changes. Some of these mediators, such as inflammatory cytokines, reactive oxygen species, and transforming growth factor β are shared among the different pathways, leading to significant overlap and interaction between them. While current treatment options for DKD have shown advancement over previous strategies, their effectiveness remains somewhat constrained as patients still experience residual risk of disease progression. Therefore, a comprehensive grasp of the molecular mechanisms underlying the onset and progression of DKD is imperative for the continued creation of novel and groundbreaking therapies for this condition. In this review, we discuss the current achievements in fundamental research, with a particular emphasis on individual factors and recent developments in DKD treatment.

Cornuside inhibits glucose-induced proliferation and inflammatory response of mesangial cells

Cornuside is a secoiridoid glucoside compound extracted from the fruits of Cornus officinalis. Cornuside has immunomodulatory and anti-inflammatory properties; however, its potential therapeutic effects on diabetic nephropathy (DN) have not been completely explored. In this study, we established an in vitro model of DN through treating mesangial cells (MMCs) with glucose. MMCs were then treated with different concentrations of cornuside (0, 5, 10, and 30 μM). Cell viability was determined using cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays. Levels of proinflammatory cytokines, including interleukin (IL)-6, tumor necrosis factor-α, and IL-1β were examined using enzyme-linked immunosorbent assay. Reverse transcription quantitative real-time polymerase chain reaction and Western blotting were performed to detect the expression of AKT and nuclear factor-kappa B (NF-κB)-associated genes. We found that cornuside treatment significantly reduced glucose-induced increase in MMC viability and expression of pro-inflammatory cytokines. Moreover, cornuside inhibited glucose-induced phosphorylation of AKT and NF-κB inhibitor alpha, decreased the expression of proliferating cell nuclear antigen and cyclin D1, and increased the expression of p21. Our study indicates that the anti-inflammatory properties of cornuside in DN are due to AKT and NF-κB inactivation in MMCs.

Protein acetylation and related potential therapeutic strategies in kidney disease

Kidney disease can be caused by various internal and external factors that have led to a continual increase in global deaths. Current treatment methods can alleviate but do not markedly prevent disease development. Further research on kidney disease has revealed the crucial function of epigenetics, especially acetylation, in the pathology and physiology of the kidney. Histone acetyltransferases (HATs), histone deacetylases (HDACs), and acetyllysine readers jointly regulate acetylation, thus affecting kidney physiological homoeostasis. Recent studies have shown that acetylation improves mechanisms and pathways involved in various types of nephropathy. The discovery and application of novel inhibitors and activators have further confirmed the important role of acetylation. In this review, we provide insights into the physiological process of acetylation and summarise its specific mechanisms and potential therapeutic effects on renal pathology.

Role of myo-inositol in acute kidney injury induced by cisplatin

There is an increasing evidence suggesting that myo-inositol (MI) may be a renoprotective factor. Our previous study revealed that decreased MI concentrations and increased excretion are often observed in animal models of renal injury and in patients with nephropathy. However, the role of MI supplementation in renal injury remains unclear. In this study, we aimed to explore the role of MI in cisplatin-induced acute kidney injury (AKI). We established a model of acute kidney injury caused by cisplatin (CDDP). Male Kunming mice were randomly divided into six groups: Sham (normal saline), CDDP (15 mg/kg), + MI (150 mg/kg), + MI (300 mg/kg), + MI (600 mg/kg) and MI (600 mg/kg). Human renal tubular epithelial cell line HK-2 cells were likewise separated into six groups at random: Control (normal saline), CDDP (20 µM), + MI (200 µM), + MI (400 µM), + MI (800 µM) and MI (800 µM). After the model was established, renal function indexes were subsequently detected, and experiments such as pathological staining analysis and protein expression analysis were performed. Our results showed that cisplatin administration led to AKI and apoptosis in mice and HK-2 cells, accompanied by markedly increased levels of MIOX, kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), whereas exogenous MI significantly attenuated kidney injury and HK-2 cell damage induced by cisplatin both in vivo and in vitro by inhibiting excessive apoptosis. Overall, our findings demonstrate that exogenous MI can reduce excessive apoptosis, thus playing a protective role in cisplatin-induced AKI, indicating that exogenous MI may be used as an adjunctive treatment modality in cisplatin-induced AKI.

LncRNA H19: a novel player in the regulation of diabetic kidney disease

Diabetic kidney disease (DKD), one of the most severe complications of diabetes mellitus (DM), has received considerable attention owing to its increasing prevalence and contribution to chronic kidney disease (CKD) and end-stage kidney disease (ESRD). However, the use of drugs targeting DKD remains limited. Recent data suggest that long non-coding RNAs (lncRNAs) play a vital role in the development of DKD. The lncRNA H19 is the first imprinted gene, which is expressed in the embryo and down-regulated at birth, and its role in tumors has long been a subject of controversy, however, in recent years, it has received increasing attention in kidney disease. The LncRNA H19 is engaged in the pathological progression of DKD, including glomerulosclerosis and tubulointerstitial fibrosis via the induction of inflammatory responses, apoptosis, ferroptosis, pyroptosis, autophagy, and oxidative damage. In this review, we highlight the most recent research on the molecular mechanism and regulatory forms of lncRNA H19 in DKD, including epigenetic, post-transcriptional, and post-translational regulation, providing a new predictive marker and therapeutic target for the management of DKD.

N6-methyladenosine methylation in kidney injury

Multiple mechanisms are involved in kidney damage, among which the role of epigenetic modifications in the occurrence and development of kidney diseases is constantly being revealed. However, N6-methyladenosine (M6A), a well-known post-transcriptional modification, has been regarded as the most prevalent epigenetic modifications in higher eukaryotic, which is involved in various biological processes of cells such as maintaining the stability of mRNA. The role of M6A modification in the mechanism of kidney damage has attracted widespread attention. In this review, we mainly summarize the role of M6A modification in the progression of kidney diseases from the following aspects: the regulatory pattern of N6-methyladenosine, the critical roles of N6-methyladenosine in chronic kidney disease, acute kidney injury and renal cell carcinoma, and then reveal its potential significance in the diagnosis and treatment of various kidney diseases. A better understanding of this field will be helpful for future research and clinical treatment of kidney diseases.

Study on the mechanism of Shenkang injection in the treatment of chronic renal failure based on the strategy of "Network pharmacology-Molecular docking-Key target validation"

OBJECTIVE

To explore the potential mechanism of Shenkang injection (SKI) in the treatment of chronic renal failure based on network pharmacology and molecular docking technology, and to verify the core targets and key pathways by using the renal failure model.

METHODS

The active components and targets of Shenkang injection were retrieved by TCMSP database, and the disease related targets were obtained by OMIM, GeneCards and other databases. Then, the intersection was obtained, and were imported into String database for PPI analysis. After further screening of core targets, GO and KEGG analysis were performed. Autodock software was used to predict the molecular docking and binding ability of the selected active ingredients and core targets. Chronic renal failure (CRF) model was established by adenine induction in rats, and the pathological observation of renal tissues was conducted. Meanwhile, the effects of Shenkang injection and its active components on core targets and pathways of renal tissues were verified.

RESULTS

The results of network pharmacology showed that the main components of Shenkang injection might be hydroxysafflor yellow A (HSYA)、tanshinol、rheum emodin、Astragaloside IV. Through enrichment analysis of core targets, it was found that Shenkang injection may play an anti-chronic renal failure effect through PI3K-Akt signaling pathway. Molecular docking results showed that the above pharmacodynamic components had strong binding ability with the target proteins PI3K and Akt. The results of animal experiments showed that renal function indexes of Shenkang injection group and pharmacodynamic component group were significantly improved compared with model group. HE staining results showed that the pathological status of the kidney was significantly improved in SKI and pharmacodynamic component treatment groups. Immunohistochemical results showed that the renal fibrosis status was significantly reduced in SKI and pharmacodynamic component treatment groups. q-RTPCR and WB results showed that the expression levels of PI3K and Akt were significantly decreased in the treatment groups (P< 0.05).

CONCLUSIONS

Shenkang injection may inhibit PI3K-Akt signaling pathway to play an anti-chronic renal failure role through the pharmacodynamic component hydroxysafflor yellow A (HSYA), tanshinol, rheum emodin, Astragaloside IV.

The role of N6-methyladenosine (m6A) in kidney diseases

Chemical modifications are a specific and efficient way to regulate the function of biological macromolecules. Among them, RNA molecules exhibit a variety of modifications that play important regulatory roles in various biological processes. More than 170 modifications have been identified in RNA molecules, among which the most common internal modifications include N6-methyladenine (m6A), n1-methyladenosine (m1A), 5-methylcytosine (m5C), and 7-methylguanine nucleotide (m7G). The most widely affected RNA modification is m6A, whose writers, readers, and erasers all have regulatory effects on RNA localization, splicing, translation, and degradation. These functions, in turn, affect RNA functionality and disease development. RNA modifications, especially m6A, play a unique role in renal cell carcinoma disease. In this manuscript, we will focus on the biological roles of m6A in renal diseases such as acute kidney injury, chronic kidney disease, lupus nephritis, diabetic kidney disease, and renal cancer.

The protective mechanism of Dehydromiltirone in diabetic kidney disease is revealed through network pharmacology and experimental validation

Background: Salvia miltiorrhiza (SM) is an effective traditional Chinese medicine for treating DKD, but the exact mechanism is elusive. In this study, we aimed to investigate and confirm the method underlying the action of the active components of SM in the treatment of DKD. Methods: Renal tissue transcriptomics and network pharmacology of DKD patients was performed to identify the active components of SM and the disease targets of DKD. Next, the point of convergence among these three groups was studied. Potential candidate genes were identified and analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The component-target networks were modelled and visualized with Cytoscape. In addition, docking studies were performed to validate our potential target predictions. Lastly, in vitro and in vivo experiments were performed to understand the role of Dehydromiltirone (DHT), the active component of SM, in the phenotypic switching of mesangial cells. Results: Transcriptomics of DKD patients' renal tissues screened 4,864 differentially expressed genes. Eighty-nine active components of SM and 161 common targets were found. Functional enrichment analysis indicated that 161 genes were enriched in apoptosis, the PI3K-AKT signaling pathway, and the AGE-RAGE signaling pathway in diabetes complications. Molecular docking and molecular dynamic simulations show that DHT can bind to functional PIK3CA pockets, thereby becoming a possible inhibitor of PIK3CA. In vitro study demonstrated that DHT reduced the expression of phenotypic switching markers α-SMA, Col-I, and FN in HMCs by downregulating the over-activation of the PI3K-AKT signaling pathway through the inhibition of PIK3CA. Furthermore, the DKD mouse model confirmed that DHT could reduce proteinuria and improve glomerular hypertrophy in vivo. Conclusion: DHT was identified as the key active component of SM, and its therapeutic effect on DKD was achieved by inhibiting the phenotypic switching of mesangial cells via the PIK3CA signaling pathway.

Regulatory roles of Osteopontin in lung epithelial inflammation and epithelial-telocyte interaction

BACKGROUND

Lung epithelial cells play important roles in lung inflammation and injury, although mechanisms remain unclear. Osteopontin (OPN) has essential roles in epithelial damage and repair and in lung cancer biological behaviours. Telocyte (TC) is a type of interstitial cell that interacts with epithelial cells to alleviate acute inflammation and lung injury. The present studies aim at exploring potential mechanisms by which OPN regulates the epithelial origin lung inflammation and the interaction of epithelial cells with TCs in acute and chronic lung injury.

METHODS

The lung disease specificity of OPN and epithelial inflammation were defined by bioinformatics. We evaluated the regulatory roles of OPN in OPN-knockdown or over-expressed bronchial epithelia (HBEs) challenged with cigarette smoke extracts (CSE) or in animals with genome OPN knockout (gKO) or lung conditional OPN knockout (cKO). Acute lung injury and chronic obstructive pulmonary disease (COPD) were induced by smoking or lipopolysaccharide (LPS). Effects of OPN on PI3K subunits and ERK were assessed using the inhibitors. Spatialization and distribution of OPN, OPN-positive epithelial subtypes, and TCs were defined by spatial transcriptomics. The interaction between HBEs and TCs was assayed by the co-culture system.

RESULTS

Levels of OPN expression increased in smokers, smokers with COPD, and smokers with COPD and lung cancer, as compared with healthy nonsmokers. LPS and/or CSE induced over-production of cytokines from HBEs, dependent upon the dysfunction of OPN. The severity of lung inflammation and injury was significantly lower in OPN-gKO or OPN-cKO mice. HBEs transferred with OPN enhanced the expression of phosphoinositide 3-kinase (PI3K)CA/p110α, PIK3CB/p110β, PIK3CD/p110δ, PIK3CG/p110γ, PIK3R1, PIK3R2 or PIK3R3. Spatial locations of OPN and OPN-positive epithelial subtypes showed the tight contact of airway epithelia and TCs. Epithelial OPN regulated the epithelial communication with TCs, and the down-regulation of OPN induced more alterations in transcriptomic profiles than the up-regulation.

CONCLUSION

Our data evidenced that OPN regulated lung epithelial inflammation, injury, and cell communication between epithelium and TCs in acute and chronic lung injury. The conditional control of lung epithelial OPN may be an alternative for preventing and treating epithelial-origin lung inflammation and injury.

The role of m6A and m6Am RNA modifications in the pathogenesis of diabetes mellitus

The rapidly developing research field of epitranscriptomics has recently emerged into the spotlight of researchers due to its vast regulatory effects on gene expression and thereby cellular physiology and pathophysiology. N⁶-methyladenosine (m⁶A) and N⁶,2'-O-dimethyladenosine (m⁶Am) are among the most prevalent and well-characterized modified nucleosides in eukaryotic RNA. Both of these modifications are dynamically regulated by a complex set of epitranscriptomic regulators called writers, readers, and erasers. Altered levels of m⁶A and also several regulatory proteins were already associated with diabetic tissues. This review summarizes the current knowledge and gaps about m⁶A and m⁶Am modifications and their respective regulators in the pathophysiology of diabetes mellitus. It focuses mainly on the more prevalent type 2 diabetes mellitus (T2DM) and its treatment by metformin, the first-line antidiabetic agent. A better understanding of epitranscriptomic modifications in this highly prevalent disease deserves further investigation and might reveal clinically relevant discoveries in the future.

Epigenetic modification in diabetic kidney disease

Diabetic kidney disease (DKD) is a common microangiopathy in diabetic patients and the main cause of death in diabetic patients. The main manifestations of DKD are proteinuria and decreased renal filtration capacity. The glomerular filtration rate and urinary albumin level are two of the most important hallmarks of the progression of DKD. The classical treatment of DKD is controlling blood glucose and blood pressure. However, the commonly used clinical therapeutic strategies and the existing biomarkers only partially slow the progression of DKD and roughly predict disease progression. Therefore, novel therapeutic methods, targets and biomarkers are urgently needed to meet clinical requirements. In recent years, increasing attention has been given to the role of epigenetic modification in the pathogenesis of DKD. Epigenetic variation mainly includes DNA methylation, histone modification and changes in the noncoding RNA expression profile, which are deeply involved in DKD-related inflammation, oxidative stress, hemodynamics, and the activation of abnormal signaling pathways. Since DKD is reversible at certain disease stages, it is valuable to identify abnormal epigenetic modifications as early diagnosis and treatment targets to prevent the progression of end-stage renal disease (ESRD). Because the current understanding of the epigenetic mechanism of DKD is not comprehensive, the purpose of this review is to summarize the role of epigenetic modification in the occurrence and development of DKD and evaluate the value of epigenetic therapies in DKD.

Bibliometric visualization analysis of gut-kidney axis from 2003 to 2022

Background: The gut-kidney axis refers to the interaction between the gastrointestinal tract and the kidneys, and its disorders have become increasingly important in the development of kidney diseases. The aim of this study is to identify current research hotspots in the field of the gut-kidney axis from 2003 to 2022 and provide guidance for future research in this field. Methods: We collected relevant literature on the gut-kidney axis from the Web of Science Core Collection (WoSCC) database and conducted bibliometric and visualization analyses using biblioshiny in R-Studio and VOSviewer (version 1.6.16). Results: A total of 3,900 documents were retrieved from the WoSCC database. The publications have shown rapid expansion since 2011, with the greatest research hotspot emerging due to the concept of the "intestinal-renal syndrome," first proposed by Meijers. The most relevant journals were in the field of diet and metabolism, such as Nutrients. The United States and China were the most influential countries, and the most active institute was the University of California San Diego. Author analysis revealed that Denise Mafra, Nosratola D. Vaziri, Fouque, and Denis made great contributions in different aspects of the field. Clustering analysis of the keywords found that important research priorities were "immunity," "inflammation," "metabolism," and "urinary toxin," reflecting the basis of research in the field. Current research frontiers in the field include "hyperuricemia," "gut microbiota," "diabetes," "trimethylamine n-oxide," "iga nephropathy," "acute kidney injury," "chronic kidney disease," "inflammation," all of which necessitate further investigation. Conclusion: This study presents a comprehensive bibliometric analysis and offers an up-to-date outlook on the research related to the gut-kidney axis, with a specific emphasis on the present state of intercommunication between gut microbiota and kidney diseases in this field. This perspective may assist researchers in selecting appropriate journals and partners, and help to gain a deeper understanding of the field's hotspots and frontiers, thereby promoting future research.

Fibroblasts-Warriors at the Intersection of Wound Healing and Disrepair

Wound healing is triggered by inflammation elicited after tissue injury. Mesenchymal cells, specifically fibroblasts, accumulate in the injured tissues, where they engage in tissue repair through the expression and assembly of extracellular matrices that provide a scaffold for cell adhesion, the re-epithelialization of tissues, the production of soluble bioactive mediators that promote cellular recruitment and differentiation, and the regulation of immune responses. If appropriately deployed, these processes promote adaptive repair, resulting in the preservation of the tissue structure and function. Conversely, the dysregulation of these processes leads to maladaptive repair or disrepair, which causes tissue destruction and a loss of organ function. Thus, fibroblasts not only serve as structural cells that maintain tissue integrity, but are key effector cells in the process of wound healing. The review will discuss the general concepts about the origins and heterogeneity of this cell population and highlight the specific fibroblast functions disrupted in human disease. Finally, the review will explore the role of fibroblasts in tissue disrepair, with special attention to the lung, the role of aging, and how alterations in the fibroblast phenotype underpin disorders characterized by pulmonary fibrosis.

Danggui Shaoyaosan attenuates doxorubicin induced Nephrotic Syndrome through regulating on PI3K/Akt Pathway

The study aimed to explore the role and the underlying mechanism of Danggui Shaoyaosan (DSS) in nephrotic syndrome (NS). NS rat model was induced by doxorubicin injection twice. After DSS treatment, inflammation and oxidative stress index were detected via ELISA. Western blot was used for the protein detection. Go and KEGG analysis was applied to evaluate target gene and signaling of DSS. MCP-5 cell was applied for the cell rescue experiments and mechanism exploration. The 24 h urine protein levels of NS rats increased significantly, which was reduced by DSS treatment in a concentration-dependent manner. After DSS treatment, levels of BUN, SCr, TG and TC were also decreased, and serum ALB and TP levels were increased in rats. GO and KEGG pathway enrichment identified PI3K-Akt to be the candidate signaling of DSS in the treatment of NS, which was activated in NS rats. The recuse experiments in MCP-5 demonstrated that IGF-1, the agonist of PI3K/AKT, abolished the beneficial role of DSS in podocyte cell viability, apoptosis, inflammation and oxidative stress. In conclusion, DSS exerts a protective role against the development of NS. The mechanism is related to the improvement of podocyte injury and the inhibition of PI3K/Akt pathway-related proteins.

Integrated analysis of transcriptome-wide m6A methylation in a Cd-induced kidney injury rat model

BACKGROUND

Accumulating evidence has demonstrated that N6-methyladenosine (m⁶A) plays important roles in a variety of diseases. However, the specific functions of m⁶A in CdCl₂-induced kidney injury remain unclear.

OBJECTIVE

Here, we investigate a transcriptome-wide map of m⁶A modifications and explore the effects of m⁶A on Cd-induced kidney injury.

MATERIALS AND METHODS

The rat kidney injury model was constructed by subcutaneous injection of CdCl₂ (0.5, 1.0, and 2.0 mg/kg). The m⁶A levels were measured by colorimetry. The level of expression of m⁶A-related enzymes were detected by reverse transcription quantitative real-time PCR analysis. Transcriptome-wide m⁶A methylome in CdCl₂ (2.0 mg/kg) and the control group were profiled by methylated RNA immunoprecipitation sequencing (MeRIP-seq). Subsequently, the sequencing data were analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG), while gene set enrichment analysis (GSEA) confirmed the functional enrichment pathways of sequencing genes. In addition, a protein-protein interaction (PPI) network was applied to select hub genes.

RESULTS

The levels of m⁶A and m⁶A regulators (METTL3, METTL14, WTAP, YTHDF2) were significantly increased in CdCl₂ groups. We identified a total of 2615 differentially expressed m⁶A peaks, 868 differentially expressed genes and 200 genes with significant changes in both m⁶A modification and gene expression levels. GO, KEGG, and GSEA analyses indicated that these genes were mainly enriched in inflammation and metabolism-related pathways such as in IL-17 signaling and fatty acid metabolism. According the result of the conjoint analysis, we identified the top ten hub genes (Fos, Hsp90aa1, Gata3, Fcer1g, Cftr, Cspg4, Atf3, Cdkn1a, Ptgs2, and Npy) which may be regulated by m⁶A and involve in CdCl₂-induced kidney damage.

CONCLUSION

This study established a m⁶A transcriptional map in a CdCl₂-induced kidney injury model and suggested that m⁶A may affect CdCl₂ induced kidney injury via regulated the inflammation and metabolism related gene.

METTL3 Mediates Epithelial-Mesenchymal Transition by Modulating FOXO1 mRNA N6 -Methyladenosine-Dependent YTHDF2 Binding: A Novel Mechanism of Radiation-Induced Lung Injury

The biological roles of epithelial-mesenchymal transition (EMT) in the pathogenesis of radiation-induced lung injury (RILI) have been widely demonstrated, but the mechanisms involved have been incompletely elucidated. N⁶ -methyladenosine (m⁶ A) modification, the most abundant reversible methylation modification in eukaryotic mRNAs, plays vital roles in multiple biological processes. Whether and how m⁶ A modification participates in ionizing radiation (IR)-induced EMT and RILI remain unclear. Here, significantly increased m⁶ A levels upon IR-induced EMT are detected both in vivo and in vitro. Furthermore, upregulated methyltransferase-like 3 (METTL3) expression and downregulated α-ketoglutarate-dependent dioxygenase AlkB homolog 5 (ALKBH5) expression are detected. In addition, blocking METTL3-mediated m⁶ A modification suppresses IR-induced EMT both in vivo and in vitro. Mechanistically, forkhead box O1 (FOXO1) is identified as a key target of METTL3 by a methylated RNA immunoprecipitation (MeRIP) assay. FOXO1 expression is downregulated by METTL3-mediated mRNA m⁶ A modification in a YTH-domain family 2 (YTHDF2)-dependent manner, which subsequently activates the AKT and ERK signaling pathways. Overall, the present study shows that IR-responsive METTL3 is involved in IR-induced EMT, probably by activating the AKT and ERK signaling pathways via YTHDF2-dependent FOXO1 m⁶ A modification, which may be a novel mechanism involved in the occurrence and development of RILI.

Epigenetic regulation in metabolic diseases: mechanisms and advances in clinical study

Epigenetics regulates gene expression and has been confirmed to play a critical role in a variety of metabolic diseases, such as diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), osteoporosis, gout, hyperthyroidism, hypothyroidism and others. The term 'epigenetics' was firstly proposed in 1942 and with the development of technologies, the exploration of epigenetics has made great progresses. There are four main epigenetic mechanisms, including DNA methylation, histone modification, chromatin remodelling, and noncoding RNA (ncRNA), which exert different effects on metabolic diseases. Genetic and non-genetic factors, including ageing, diet, and exercise, interact with epigenetics and jointly affect the formation of a phenotype. Understanding epigenetics could be applied to diagnosing and treating metabolic diseases in the clinic, including epigenetic biomarkers, epigenetic drugs, and epigenetic editing. In this review, we introduce the brief history of epigenetics as well as the milestone events since the proposal of the term 'epigenetics'. Moreover, we summarise the research methods of epigenetics and introduce four main general mechanisms of epigenetic modulation. Furthermore, we summarise epigenetic mechanisms in metabolic diseases and introduce the interaction between epigenetics and genetic or non-genetic factors. Finally, we introduce the clinical trials and applications of epigenetics in metabolic diseases.

Integrated analysis of RNA methylation regulators crosstalk and immune infiltration for predictive and personalized therapy of diabetic nephropathy

BACKGROUND

RNA methylation is a widely known post-transcriptional regulation which exists in many cancer and immune system diseases. However, the potential role and crosstalk of five types RNA methylation regulators in diabetic nephropathy (DN) and immune microenvironment remain unclear.

METHODS

The mRNA expression of 37 RNA modification regulators and RNA modification regulators related genes were identified in 112 samples from 5 Gene Expression Omnibus datasets. Nonnegative Matrix Factorization clustering method was performed to determine RNA modification patterns. The ssGSEA algorithms and the expression of human leukocyte antigen were employed to assess the immune microenvironment characteristics. Risk model based on differentially expression genes responsible for the modification regulators was constructed to evaluate its predictive capability in DN patients. Furthermore, the results were validated by using immunofluorescence co-localizations and protein experiments in vitro.

RESULTS

We found 24 RNA methylation regulators were significant differently expressed in glomeruli in DN group compared with control group. Four methylation-related genes and six RNA regulators were introduced into riskScore model using univariate Logistic regression and integrated LASSO regression, which could precisely distinguish the DN and healthy individuals. Group with high-risk score was associated with high immune infiltration. Three distinct RNA modification patterns were identified, which has significant differences in immune microenvironment, biological pathway and eGFR. Validation analyses showed the METTL3, ADAR1, DNMT1 were upregulated whereas YTHDC1 was downregulated in DN podocyte cell lines comparing with cells cultured by the normal glucose.

CONCLUSION

Our study reveals that RNA methylation regulators and immune infiltration regulation play critical roles in the pathogenesis of DN. The bioinformatic analyses combine with verification in vitro could provide robust evidence for identification of predictive RNA methylation regulators in DN.

Circular RNA ITCH increases sorafenib-sensitivity in hepatocellular carcinoma via sequestering miR-20b-5p and modulating the downstream PTEN-PI3K/Akt pathway

BACKGROUNDS

Sorafenib-resistance leads to poor prognosis and high mortality in advanced hepatocellular carcinoma (HCC), and this study aims to investigate the functional role of a circular RNA ITCH (circITCH) in regulating the sorafenib-resistance of HCC and its underlying mechanisms.

METHODS

The expression of circITCH in HCC tissues and cell lines were detected by performing quantitative real-time polymerase chain reaction. Sorafenib-resistant HCC cells were transfected with PLCDH-circITCH to upregulate circITCH and intervened with sorafenib, and MTT assay, flow cytometry and transwell assay were used to test the cell viability, apoptosis and migration ability, respectively. The downstream target of circITCH were explored by using bioinformatic analysis, dual luciferase reporter system and Western blot.

RESULTS

CircITCH was significantly down-regulated in HCC tissues and cell lines, compared with their normal counterparts. Especially, in contrast with the sorafenib-sensitive HCC cells, continuous sorafenib treatment decreased the expression levels of circITCH in the sorafenib-resistant HCC cells. Overexpression of circITCH increased sorafenib-sensitivity, promoted cell apoptosis and reduced cell migration abilities in the sorafenib-resistant HCC cells. Mechanically, circITCH elevated PTEN expression to inactivate the PI3K/Akt signals through negatively regulating miR-20b-5p in HCC, and upregulating miR-20b-5p or inhibiting PTEN abolished the enhancing effect of circITCH overexpression on sorafenib-induced cytotoxicity in sorafenib-resistant HCC cells.

CONCLUSION

Taken together, this study proves that circITCH enhances sorafenib-sensitivity in sorafenib-resistant HCC cells via regulating the miR-20b-5p/PTEN/PI3K/Akt signaling cascade, which highlights the potential value of circITCH as a target for enhancing the sorafenib-sensitivity in HCC.

Advancing targeted protein degradation for metabolic diseases therapy

The development and application of traditional drugs represented by small molecule chemical drugs and biological agents, especially inhibitors, have become the mainstream drug development. In recent years, targeted protein degradation (TPD) technology has become one of the most promising methods to remove specific disease-related proteins using cell self-destruction mechanisms. Many different TPD strategies are emerging based on the ubiquitin-proteasome system (UPS) and the autophagy-lysosomal pathway (ALP), including but not limited to proteolysis-targeting chimeras (PROTAC), molecular glues (MG), lysosome targeting chimeras (LYTAC), chaperone-mediated autophagy (CMA)-targeting chimeras, autophagy-targeting chimera (AUTAC), autophagosome-tethering compound (ATTEC), and autophagy-targeting chimera (AUTOTAC). The advent of targeted degradation technology can change most protein targets in human cells from undruggable to druggable, greatly expanding the therapeutic prospect of refractory diseases such as metabolic syndrome. Here, we summarize the latest progress of major TPD technologies, especially in metabolic syndrome and look forward to providing new insights for drug discovery.

N6-methyladenosine in macrophage function: a novel target for metabolic diseases

N6-methyladenosine (m⁶A) is one of the most prevalent internal transcriptional modifications. Evidence has highlighted changes in m⁶A in metabolic disorders and various metabolic diseases. However, the precise mechanisms of these m⁶A changes in such conditions are not understood. Macrophages are crucial for the innate immune system and exert either beneficial or harmful roles in metabolic disease. Notably, m⁶A was found to be closely related to macrophage phenotype and dysfunction. In this review, we summarize m⁶A in macrophage function from the perspective of macrophage development, activation, and polarization, pyroptosis, and metabolic disorders. Furthermore, we discuss how m⁶A-mediated macrophage function affects metabolic diseases, including atherosclerosis and nonalcoholic fatty liver disease (NAFLD). Finally, we discuss challenges and prospects for m⁶A in macrophage and metabolic diseases with the aim of providing guidance for the treatment of metabolic diseases.

Title: Bioinformatic Identification of Genes Involved in Diabetic Nephropathy Fibrosis and their Clinical Relevance

Tubulointerstitial fibrosis is an important pathological feature of diabetic nephropathy that is associated with impaired renal function. However, the mechanism by which fibrosis occurs in diabetic nephropathy is unclear. Differentially expressed genes were identified from transcriptome profiles of renal tissue from diabetic patients and unilateral ureteral obstruction mice and intersected to obtain genes that may be involved in diabetic fibrosis. Biological function analysis and protein-protein interaction network analysis were performed. ROC curve and Pearson correlation analysis between hub genes were performed and glomerular filtration rate estimated. Finally, the RNA levels of hub genes were measured using real-time PCR. A total of 283 genes were identified as potentially involved in diabetic nephropathy fibrosis. TYROBP, CTSS, LCP2, LUM and TLR7 were identified as aberrantly expressed hub genes. Immune cell infiltration analysis demonstrated higher numbers of cytotoxic lymphocytes, B lineage cells, monocyte lineage cells, myeloid dendritic cells, neutrophils, and fibroblasts in the diabetic nephropathy group. The areas under ROC curves for TYROBP, CTSS, LCP2, LUM and TLR7 were 0.9167, 0.9583, 0.9917, 0.93333, and 0.9583, respectively (P < 0.001), and their correlation coefficients with estimated glomerular filtration rate were - 0.8332, - 0.752, - 0.7875, - 0.7567, and - 0.7136, respectively (P < 0.001). The RNA levels of TYROBP, CTSS, LUM and TLR7 were upregulated in high-glucose-treated human renal tubular epithelial cells (P < 0.005). Our study identified TYROBP, CTSS, LCP2, LUM and TLR7 as potentially involved in diabetic nephropathy fibrosis. Furthermore, TYROBP, CTSS, LUM and TLR7 may be associated with epithelial-mesenchymal transition of tubular epithelial cells.

RNA N6 -methyladenosine modifications and potential targeted therapeutic strategies in kidney disease

Epigenetic modifications have received increasing attention and have been shown to be extensively involved in kidney development and disease progression. Among them, the most common RNA modification, N⁶ -methyladenosine (m⁶ A), has been shown to dynamically and reversibly exert its functions in multiple ways, including splicing, export, decay and translation initiation efficiency to regulate mRNA fate. Moreover, m⁶ A has also been reported to exert biological effects by destabilizing base pairing to modulate various functions of RNAs. Most importantly, an increasing number of kidney diseases, such as renal cell carcinoma, acute kidney injury and chronic kidney disease, have been found to be associated with aberrant m⁶ A patterns. In this review, we comprehensively review the critical roles of m⁶ A in kidney diseases and discuss the possibilities and relevance of m⁶ A-targeted epigenetic therapy, with an integrated comprehensive description of the detailed alterations in specific loci that contribute to cellular processes that are associated with kidney diseases.

A natural products solution to diabetic nephropathy therapy

Diabetic nephropathy is one of the most common complications in diabetes. It has been shown to be the leading cause of end-stage renal disease. However, due to their complex pathological mechanisms, effective therapeutic drugs other than angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), which have been used for 20 years, have not been developed so far. Recent studies have shown that diabetic nephropathy is characterized by multiple signalling pathways and multiple targets, including inflammation, apoptosis, pyroptosis, autophagy, oxidative stress, endoplasmic reticulum stress and their interactions. It definitely exacerbates the difficulty of therapy, but at the same time it also brings out the chance for natural products treatment. In the most recent two decades, a large number of natural products have displayed their potential in preclinical studies and a few compounds are under invetigation in clinical trials. Hence, many compounds targeting these singals have been emerged as a comprehensive blueprint for treating strategy of diabetic nephropathy. This review focuses on the cellular and molecular mechanisms of natural prouducts that alleviate this condition, including preclinical studies and clinical trials, which will provide new insights into the treatment of diabetic nephropathy and suggest novel ideas for new drug development.