DKK3 promotes renal fibrosis by increasing MFF-mediated mitochondrial dysfunction in Wnt/β-catenin pathway-dependent manner

BACKGROUND

Chronic kidney disease (CKD) lacks effective treatments and renal fibrosis (RF) is one of CKD's outcomes. Dickkopf 3 (DKK3) has been identified as an agonist in CKD. However, the underlying mechanisms of DKK3 in CKD are not fully understood.

METHODS

H2O2-treated HK-2 cells and ureteric obstruction (UUO) mice were used as RF models. Biomarkers, Masson staining, PAS staining, and TUNEL were used to assess kidney function and apoptosis. Oxidative stress and mitochondria function were also evaluated. CCK-8 and flow cytometry were utilized to assess cell viability and apoptosis. Western blotting, IHC, and qRT-PCR were performed to detect molecular expression levels. Immunofluorescence was applied to determine the subcellular localization. Dual luciferase assay, MeRIP, RIP, and ChIP were used to validate the m6A level and the molecule interaction.

RESULTS

DKK3 was upregulated in UUO mouse kidney tissue and H2O2-treated HK-2 cells. Knockdown of DKK3 inhibited oxidative stress, maintained mitochondrial homeostasis, and alleviated kidney damage and RF in UUO mice. Furthermore, DKK3 silencing suppressed HK-2 cell apoptosis, oxidative stress, and mitochondria fission. Mechanistically, DKK3 upregulation was related to the high m6A level regulated by METTL3. DKK3 activated TCF4/β-catenin and enhanced MFF transcriptional expression by binding to its promoter. Overexpression of MFF reversed in the inhibitory effect of DKK3 knockdown on cell damage.

CONCLUSION

Upregulation of DKK3 caused by m6A modification activated the Wnt/β-catenin pathway to increase MFF transcriptional expression, leading to mitochondrial dysfunction and oxidative stress, thereby promoting RF progression.

[Comparison of the efficacy of different surgical strategies in the treatment of patients with initially resectable gastric cancer liver metastases]

Objective: To examine the impact of varied surgical treatment strategies on the prognosis of patients with initial resectable gastric cancer liver metastases (IR-GCLM). Methods: This is a retrospective cohort study. Employing a retrospective cohort design, the study selected clinicopathological data from the national multi-center retrospective cohort study database, focusing on 282 patients with IR-GCLM who underwent surgical intervention between January 2010 and December 2019. There were 231 males and 51 males, aging (M(IQR)) 61 (14) years (range: 27 to 80 years). These patients were stratified into radical and palliative treatment groups based on treatment decisions. Survival curves were generated using the Kaplan-Meier method and distinctions in survival rates were assessed using the Log-rank test. The Cox risk regression model evaluated HR for various factors, controlling for confounders through multivariate analysis to comprehensively evaluate the influence of surgery on the prognosis of IR-GCLM patients. A restricted cubic spline Cox proportional hazard model assessed and delineated intricate associations between measured variables and prognosis. At the same time, the X-tile served as an auxiliary tool to identify critical thresholds in the survival analysis for IR-GCLM patients. Subgroup analysis was then conducted to identify potential beneficiary populations in different surgical treatments. Results: (1) The radical group comprised 118 patients, all undergoing R0 resection or local physical therapy of primary and metastatic lesions. The palliative group comprised 164 patients, with 52 cases undergoing palliative resections for gastric primary tumors and liver metastases, 56 cases undergoing radical resections for gastric primary tumors only, 45 cases undergoing palliative resections for gastric primary tumors, and 11 cases receiving palliative treatments for liver metastases. A statistically significant distinction was observed between the groups regarding the site and the number of liver metastases (both P<0.05). (2) The median overall survival (OS) of the 282 patients was 22.7 months (95%CI: 17.8 to 27.6 months), with 1-year and 3-year OS rates were 65.4% and 35.6%, respectively. The 1-year OS rates for patients in the radical surgical group and palliative surgical group were 68.3% and 63.1%, while the corresponding 3-year OS rates were 42.2% and 29.9%, respectively. A comparison of OS between the two groups showed no statistically significant difference (P=0.254). Further analysis indicated that patients undergoing palliative gastric cancer resection alone had a significantly worse prognosis compared to other surgical options (HR=1.98, 95%CI: 1.21 to 3.24, P=0.006). (3) The size of the primary gastric tumor significantly influenced the patients' prognosis (HR=2.01, 95%CI: 1.45 to 2.79, P<0.01), with HR showing a progressively increasing trend as tumor size increased. (4) Subgroup analysis indicates that radical treatment may be more effective compared to palliative treatment in the following specific cases: well/moderately differentiated tumors (HR=2.84, 95%CI 1.49 to 5.41, P=0.001), and patients with liver metastases located in the left lobe of the liver (HR=2.06, 95%CI 1.19 to 3.57, P=0.010). Conclusions: In patients with IR-GCLM, radical surgery did not produce a significant improvement in the overall prognosis compared to palliative surgery. However, within specific patient subgroups (well/moderately differentiated tumors, and patients with liver metastases located in the left lobe of the liver), radical treatment can significantly improve prognosis compared to palliative approaches.

Wnt/β-catenin Pathway Aggravates Renal Fibrosis by Activating PUM2 Transcription to Repress YME1L-mediated Mitochondrial Homeostasis

Chronic kidney disease (CKD) affects more than 10% of people worldwide and is a leading cause of death. However, the pathogenesis of CKD remains elusive. The oxidative stress and mitochondrial membrane potential were detected using Enzyme-linked immunosorbent assay and JC-1 assay. Co-immunoprecipitation, dual-luciferase assay, chromatin IP, RNA IP and RNA pull-down were used to validate the interactions among genes. Exploiting a H2O2-induced fibrosis model in vitro, PUM2 expression was upregulated in Human kidney 2 cell (HK-2) cells, along with reduced cell viability, enhanced oxidative stress, impaired mitochondrial potential, and upregulated expressions of fibrosis-associated proteins. While PUM2 knockdown reversed the H2O2-induced injury in HK-2 cells. Mechanically, Wnt/β-catenin pathway activated PUM2 transcription via TCF4. It was further identified that Wnt/β-catenin pathway inhibited YME1L expression through PUM2-mediated destabilizing of its mRNA. PUM2 aggravated H2O2-induced oxidative stress, mitochondrial dysfunction, and renal fibrosis in HK-2 cell via suppressing YME1L expression. Our study revealed that Wnt/β-catenin aggravated renal fibrosis by activating PUM2 transcription to repress YME1L-mediated mitochondrial homeostasis, providing novel insights and potential therapeutic targets for the treatment of kidney fibrosis.

Optimized rituximab regimen versus recommended regimen for idiopathic membranous nephropathy: A single-center retrospective cohort study

BACKGROUND

Rituximab (RTX) has become the first-line treatment for idiopathic membranous nephropathy (IMN). Compared with conventional therapy, rituximab therapy has a more favorable safety profile. However, the recommended RTX dose as a flux may have its limitations. The aim of this study was to investigate the clinical efficacy and safety of three regimens, including a cyclic corticosteroid-cyclophosphamide regimen and two different doses of RTX regimens, for the treatment of IMN.

METHODS

We recruited 58 patients with IMN confirmed by renal biopsy. 20 patients were treated with a cycle regimen, 22 patients were received RTX with 500 mg per week, totaling a dose of 2000 mg (optimized RTX group), and 16 patients received RTX with 1000 mg at day 1 and day 15 (recommended RTX group). Treatment responses, including complete remission (CR) and partial remission (PR), and outcome adverse events such as steroid diabetes, infections and a drop in white blood cell count, were compared among the three groups after 9 months of follow-up.

RESULTS

At 9-month follow-up, the composite remission rates (CR + PR) were 90 %, 72.7 %, and 75 % for the cycle regimen group, optimized RTX group, and recommended RTX group, respectively, with CR of 35 %, 22.7 %, and 25 %, respectively. There was no statistical difference between the three groups on CR and composite remission. Kaplan-Meier survival analyses showed no significant differences in cumulative CR rates and cumulative composite remission rates among the three groups (P = 0.632, P = 0.258). The cycle regimen group had a higher risk of steroid diabetes (35 %). Compared with the recommended RTX regimen, the optimized regimen reduced the incidence of adverse events of infection (9.1 % vs. 37.5 %, P = 0.049), especially in patients older than 60 years of age (P = 0.026). A lower anti-PLA2R at baseline may be associated with a higher risk of infection (P = 0.043).

CONCLUSIONS

The efficiency of low-dose and long-course of RTX regiment is not inferior to the recommended treatment regimen, and this regimen can effectively reduce the incidence of infection in patients with IMN. Moreover, we recommend a low-dose, long course of RTX treatment for the elderly.

[Quality control of lymph node dissection for locally advanced gastric cancer]

Numerous studies have confirmed that D2 lymphadenectomy is the standard surgery for locally advanced gastric cancer. Standardized lymph node dissection plays a crucial role in ensuring surgical quality and efficacy. It is recommended to perform D2 lymph node dissection according to the 6th edition of the Japanese gastric cancer treatment guidelines. For lymph nodes beyond the scope of D2 lymph node dissection, such as No.10, 13, 14v, 16 and mediastinal lymph nodes, selective D2+ lymph node dissection can be performed, which may be advantageous for some patients. Currently, omentectomy is the standard surgical procedure for locally advanced gastric cancer. However, the clinical significance of gastrectomy with preservation of the greater omentum requires further validation through large-scale clinical trials. Standardized ex vivo lymph node dissection is important for accurate postoperative staging, and it is recommended to harvest more than 30 lymph nodes to avoid staging deviation.

Annexin A1 may contribute to the morphological changes in podocytes by mediating endocytic vesicle fusion and transport via promotion of SNARE assembly in idiopathic membranous nephropathy

BACKGROUND

Annexin A1 is a membrane-associated calcium-binding protein that participates in the progression of many diseases by facilitating vesicle aggregation. It has been documented that reducing vesicle formation alleviates podocyte injury and albuminuria in idiopathic membranous nephropathy (IMN). However, the role of Annexin A1 (ANXA1) in IMN is unknown.

METHODS

Electron microscopy was used to observe the numbers of vesicles in podocytes. The expression of ANXA1 in IMN was investigated by bioinformatics analysis. We validated the hub genes with the Nephroseq V5 online tool and microarray data from the GEO. Immunohistochemical staining and qPCR were performed to measure gene and protein expression.

RESULTS

The numbers of vesicles in IMN podocytes were significantly increased. Bioinformatics analysis showed that ANXA1, one of the differentially expressed genes, was upregulated in glomeruli from IMN patients. In the validation database and dataset, we confirmed that ANXA1 expression was upregulated in the glomeruli of IMN patients. We revealed that the increased expression of ANXA1 was negatively correlated with the glomerular filtration rate (GFR) and proteinuria. Moreover, ANXA1 was enriched in the biological process of vesicle fusion, in which the expression of SNAREs and the SNARE complex was increased. Finally, the expression of ANXA1 and genes related to SNAREs and the SNARE complex was upregulated in glomeruli from IMN patients according to immunohistochemical staining and qPCR.

CONCLUSION

We conclude that ANXA1 may mediate endocytic vesicle fusion and transport by promoting SNARE assembly, contributing to the morphological changes in podocytes and massive proteinuria in IMN.

Identification and characterization of two immune-related subtypes in human chronic kidney disease

BACKGROUND

Immune response plays a vital role in the initiation and development of chronic kidney disease (CKD). Detailed mechanisms and specific immune-related biomarkers of CKD need further clarification. We aimed to identify and characterize immune-related infiltrates that are implicated in the CKD development using a bioinformatics method.

METHODS

The expression profiles of GSE66494 dataset were acquired from the Gene Expression Omnibus (GEO) database. Patients with CKD were divided into low- vs. high-immune subtypes based on their immune score. Based on such analysis, we identified differentially expressed genes (DEGs) of low- and high-immune subtypes. The weight gene co-expression network analysis (WGCNA) was used to identify immune-associated modules between two subtypes. The gene set enriched (GSEA) and variation (GSVA) analyses were correlated with their functional types using the molecular complex detection (MCODE) method. Finally, the immune infiltration landscape between subtypes was revealed using the xCell algorithm.

RESULTS

The total number of 131 differentially expressed immune-related genes (DEIRGs) were identified between low- vs. high-immune subtypes. Out of them GSEA/GSVA results identified and enriched immune- and inflammation-related pathways. In particular, GSVA results indicated that immune-related pathways were activated in high-immune subgroups. The core DEIRG genes that were identified to be involved in CKD development included: the protein tyrosine phosphatase receptor type C (PTPRC; also known as CD45) regulating cell growth and differentiation, an early activation marker (CD69), co-receptor for T cell receptor (CD8A), and T cell co-stimulatory signal (CD28). These core DEIRD genes were further verified by the GSE96804 dataset. We also found a higher proportion of immune cells infiltrating the high-immune subgroup. Furthermore, the four core genes were positively correlated with most immune cell types.

CONCLUSION

Among 131 DEIRG genes, four genes (PTPRC, CD69, CD8A, and CD28) were identified as potential biomarkers associated with the immune cell infiltration in CKD patients, which may provide a novel insight for immunotherapy for CKD.

Mendelian randomization reveals systemic lupus erythematosus and rheumatoid arthritis and risk of adverse pregnancy outcomes

BACKGROUND

The effect of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) on adverse pregnancy outcomes is a controversial topic. This study aimed to use Mendelian randomization (MR) analysis to assess the causal relationship between SLE, RA and adverse pregnancy outcomes.

METHODS

Genetic variants for SLE and RA, as well as adverse pregnancy outcomes, were derived from pooled statistics from large public genome-wide association studies. Several methods, such as inverse variance weighting (IVW), MR-Egger, weighted median and MR-Pleiotropic Residuals Sum and Outliers, were employed to estimate two-sample causality.

RESULTS

Genetic prediction of SLE was associated with higher odds of preterm labour [odds ratio (OR) 1.03, 95 % confidence interval (CI) 1.01-1.05; p = 0.008]. RA was associated with higher odds of preterm labour (OR 1.03, 95 % CI 1.01-1.06; p = 0.009), pre-eclampsia or eclampsia (OR 1.04, 95 % CI 1.01-1.07; p = 0.005), and poor fetal growth (OR 1.08, 95 % CI 1.04-1.12; p = 2.91 × 10-5). The results of bidirectional MR analysis did not indicate that SLE was associated with spontaneous abortion, pre-eclampsia or eclampsia, preterm rupture of membranes, or poor fetal growth (p-value for IVW 0.13-0.97).

CONCLUSIONS

This study found a genetic association between SLE and the risk of preterm labour, and highlights the importance of perinatal care and monitoring for patients with SLE. Furthermore, RA was found to be associated with a wide range of adverse outcomes, including preterm labour, pre-eclampsia or eclampsia, and poor fetal growth; as such, there is a need for more intensive therapeutic interventions and prenatal monitoring.

Bioinformatics reveals the pathophysiological relationship between diabetic nephropathy and periodontitis in the context of aging

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes mellitus. Periodontitis (PD) is a microbially-induced chronic inflammatory disease that is thought to have a bidirectional relationship with diabetes mellitus. DN and PD are recognized as models associated with accelerated aging. This study is divided into two parts, the first of which explores the bidirectional causal relationship through Mendelian randomization (MR). The second part aims to investigate the relationship between PD and DN in terms of potential crosstalk genes, aging-related genes, biological pathways, and processes using bioinformatic methods. MR analysis showed no evidence to support a causal relationship between DN and PD (P = 0.34) or PD and DN (P = 0.77). Using the GEO database, we screened 83 crosstalk genes overlapping in two diseases. Twelve paired genes identified by Pearson correlation and the four hub genes in the key cluster were jointly evaluated as key crosstalk-aging genes. Using support vector machine recursive feature elimination (SVM-RFE) and maximal clique centrality (MCC) algorithms, feature selection established five genes as the key crosstalk-aging genes. Based on five key genes, an ANN diagnostic model with reliable diagnosis of two diseases was developed. Gene enrichment analysis indicates that AGE-RAGE pathway signaling, the complement system, and multiple immune inflammatory pathways may be involved in common features of both diseases. Immune infiltration analysis reveals that most immune cells are differentially expressed in PD and DN, with dendritic cells and T cells assuming vital roles in both diseases. Overall, although there is no causal link, CSF1R, CXCL6, VCAM1, JUN and IL1B may be potential crosstalk-aging genes linking PD and DN. The common pathways and markers explored in this study could contribute to a deeper understanding of the common pathogenesis of both diseases in the context of aging and provide a theoretical basis for future research.

[Clinical implications of Naples prognostic scores in patients with resectable Siewert type II-III adenocarcinoma of the esophagogastric junction]

Objective: To evaluate the clinical value of preoperative Naples prognostic scores (NPS) in patients with resectable Siewert type II-III esophagogastric junction adenocarcinoma (AEG). Methods: In this retrospective observational study we collected and analyzed relevant data of patients with Siewert Type II-III AEG treated in the Department of Gastric Cancer, Tianjin Medical University Cancer Institute and Hospital from January 2014 to December 2018. NPS were calculated using preoperative albumin concentration, total cholesterol concentration, neutrophil/lymphocyte ratio, and lymphocyte/monocyte ratio and used to allocate patients into three groups: NTS-0 (0 points), NTS-1 (1-2 points) and NTS-2 (3-4 points). Kaplan-Meier was used to calculate disease-free survival (DFS) and overall survival (OS) in each NPS group and the log-rank test to compare these groups. Univariate and multivariate survival analyes were performed using the Cox regression model. Time-dependent receiver operating characteristic curves were constructed to compare the relationships between four commonly used tools for evaluating inflammatory responses and nutritional status:NPS, systemic inflammatory response scores, nutrient control status (CONUT), and prognostic nutrition index (PNI). Results: The study cohort comprised 221 patients with AEG of median age 63.0 (36.0-87.0) years. There were 190 men (86.0%) and 31 women (14.0%). As to pTNM stage, 47 patients (21.3%) had Stage I disease, 68 (30.8%) Stage II, and 106 (48.0%) Stage III. One hundred and forty-seven patients (66.5%) had Siewert Type II disease and 74 (33.5%) Siewert type III. There were 45 patients (20.4%) in the NPS-0, 142 (64.2%) in the NPS-1 and 34 (15.4%) in the NPS-2 groups. Higher NPS scores were significantly associated with older patients (χ²=5.056, P=0.027) and higher TNM stages (H=5.204,P<0.001). The median follow-up was 39 (6-105) months; 16 patients (7.2%) were lost to follow-up. The median OS in the NPS-0, NPS-1, and NPS-2 groups were 78.4, 63.1, and 37.0 months, respectively; these differences are statistically significant (P=0.021). Univariate and multivariate Cox regression analysis identified the following as independently and significantly associated with OS in patients with Siewert Type II-III: TNM stage (Stage II: HR=2.182, 95%CI: 1.227-3.878, P=0.008; Stage III: HR=3.534, 95%CI: 1.380-6.654, P<0.001), tumor differentiation (G3: HR=1.995, 95%CI: 1.141-3.488, P=0.015), vascular invasion (HR=2.172, 95%CI: 1.403-3.363, P<0.001), adjuvant chemotherapy (HR=0.326, 95%CI: 0.200-0.531, P<0.001), NPS (NPS-1: HR=2.331, 95%CI: 1.371-3.964, P=0.002; NPS-2: HR=2.494, 95%CI: 1.165-5.341, P=0.019), SIS group (NPS-1: HR=2.170, 95%CI: 1.244-3.784, P=0.006; NPS-2: HR=2.291, 95%CI: 1.052-4.986, P=0.037), and CONUT (HR=1.597, 95% CI: 1.187-2.149, P=0.038). The median DFS in the NPS-0, NPS-1, and NPS-2 groups was 68.6, 52.5, and 28.3 months, respectively; these differences are statistically significant (P=0.009). Univariate and multivariate Cox regression analysis identified the following as independently and significantly associated with DFS in patients with Siewert Type II-III AEG: TNM stage (StageⅡ: HR=2.789, 95%CI:1.210-6.428, P=0.016; Stage III: HR=10.721, 95%CI:4.709-24.411, P<0.001), adjuvant chemotherapy (HR=0.640, 95% CI: 0.432-0.946, P=0.025), and NPS (NPS-1: HR=1.703, 95%CI: 1.043-2.782, P=0.033; NPS-2: HR=3.124, 95%CI:1.722-5.666, P<0.001). Time-dependent receiver operating characteristic curves showed that NPS was more accurate in predicting OS and DFS in patients with Siewert Type II-III AEG than were systemic inflammatory response scores, CONUT, or PNI scores. Conclusion: NPS is associated with age and TNM stage, is an independent prognostic factor in patients who have undergone resection of Siewert type II-III AEG, and is better than SIS, CONUT, or PNI in predicting survival.

Identification of molecular mediators of renal sarcopenia risk: a mendelian randomization analysis

BACKGROUND

Observational studies have shown an association between reduced renal function and the risk of sarcopenia. However, the causal relationship and the underlying biological mechanisms remain uncertain. Using a Mendelian randomization (MR) framework, we investigated the causal role of 27 hypothetical risk mediators, including metabolites, hormones, inflammation, and stress traits, on the risk of sarcopenia.

METHODS

Instrumental variables (IVs) to proxy renal function were identified by selecting single nucleotide polymorphisms (SNPs) reliably associated with creatinine and cystatin C-based glomerular filtration rate (GFR) in CKDGen summary data. IVs for putative risk traits and sarcopenia traits were constructed from relevant genome-wide association studies (GWAS). MR estimated effects were obtained using an inverse-variance weighted effects model, and various sensitivity analyses were performed. The mediating role of hypothetical risk factors in the relationship between GFR and sarcopenia was assessed through multivariate MR.

RESULTS

Genetically predicted reduced GFRcrea was associated with higher odds of appendicular lean mass (ALM) (odds ratio (OR): 0.64, 95% confidence interval (CI) 0.37 to 0.68) and grip strength (OR: 0.67; 95% CI 0.58 to 0.78). Likewise, GFRcys highlighted a causal relationship with ALM (OR: 0.52; 95% CI 0.42 to 0.65) and grip strength (OR: 0.66; 95% CI 0.59 to 0.74). Both estimated GFR (eGFR) were negatively associated with IGF-1, IL-16, 25(OH)D, triglycerides (range of effect size per standard deviation: -0.81 to -0.30), and positively correlated with HDL cholesterol (0.62, 0.31). There was a positive correlation between IGF-1, fasting insulin and ALM as well as grip strength (OR range: 1.04-1.67) and a negative correlation between serum CRP and ALM (OR: 0.95) as well as grip strength (OR: 0.98). Additionally, genetically predicted IL-1β (OR: 0.95) and total cholesterol (OR: 0.96) were negatively associated with ALM. We found evidence that IGF-1 mediates the relationship between eGFR and risk for muscle mass and strength.

CONCLUSIONS

This MR study provides insight into the potential causal mechanisms between renal function and the risk of sarcopenia and proposes IGF-1 as a potential target for the prevention of renal sarcopenia.

Abnormalities in the SIRT1-SIRT3 axis promote myocardial ischemia-reperfusion injury through ferroptosis caused by silencing the PINK1/Parkin signaling pathway

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) is one of the main reasons for poor prognosis in patients with ischemic cardiomyopathy (ICM). To date, the mechanism remains unknown. As members of the silent information regulator 2 (SIR2) family, both SIRT1 and SIRT3 have been shown to play critical roles in protecting cardiomyocytes against MIRI, but their specific protective mechanism, their interact between the two and their relationship with ferroptosis are still unclear. Hence, in this study, we investigated the interact and specific mechanism of SIRT1 and SIRT3 in protecting cardiomyocytes against MIRI, as well as their association with ferroptosis.

METHODS

Bioinformatics analysis methods were used to explore the expression of SIRT1 and SIRT3 during MIRI, and then a cell hypoxia/reoxygenation injury model was constructed to verify the results. Then, Pearson correlation analysis was further used to explore the relationship between SIRT1 and SIRT3, whose roles in the regulation of ferroptosis were also analysed by gene knock down, Western Blotting and flow cytometry. Several biomarkers, such as Fe2+ concentration, lipid peroxidation marker MDA and mitochondrial membrane potential (MMP), were used to evaluate changes in ferroptosis.

RESULTS

The expression of SIRT1 and SIRT3 was abnormal during MIRI, and SIRT1 was significantly negatively correlated with SIRT3 in the SIRT1-SIRT3 axis. Further analysis revealed that the SIRT1-SIRT3 axis was closely correlated with ferroptosis, and its silencing effectively increase the incidence of ferroptosis. Furthermore, SIRT1-SIRT3 axis silencing was accompanied by changes in PINK1, Parkin, P62/SQSTM1 and LC3 expression. PINK1 silencing significantly increased the incidence of ferroptosis, while resveratrol (Res) and/or honokiol (HKL) effectively reversed the outcome.

CONCLUSION

Abnormalities in the SIRT1-SIRT3 axis promote MIRI through ferroptosis caused by silencing the PINK1/Parkin signaling pathway.

Clinical efficacy and safety of beraprost sodium in the treatment of nephrotic syndrome: A meta-analysis

BACKGROUND

Beraprost sodium has been shown to have positive effects in the kidney; however, its efficacy and safety in the treatment of nephrotic syndrome (NS) are currently unknown. Therefore, the aim of this meta-analysis was to evaluate the clinical efficacy and safety of beraprost sodium in the treatment of NS.

METHODS

We systematically searched EMBASE, PubMed, MEDLINE, China National Knowledge Internet (CNKI), Chinese Biomedical Database (CBM), and Wanfang database for articles from their inception to August 2022.

RESULTS

A total of 12 randomized controlled trials (RCTs) involving 1200 subjects were collected for careful evaluation. The meta-analysis indicated that compared with the controls, combination therapy with berprost sodium could remarkably improve the total effective rate (odds ratio 4.21, 95% confidence interval [CI]: 2.87 to 7.25) and reduce 24 hours proteinuria (mean difference [MD] -1.03, 95% CI: -1.26 to -0.8), serum creatinine (MD -18.39; 95% CI: -27.81 to -8.98), blood urea nitrogen (MD -1.43,95% CI: -1.94 to -0.92), serum total cholesterol (MD -1.24; 95% CI: -1.36 to -1.11), and triglyceride (MD -0.69; 95% CI: -1.03 to -0.35), and increase serum albumin (MD 4.96, 95% CI: 2.98 to 6.93). But the adverse effects of dizziness and headache were higher (RD = 0.05. 95% CI: 0.02 to 0.08).

CONCLUSION

For NS patients, combination therapy with beraprost sodium can achieve higher clinical efficacy and significant improvement in renal function than conventional therapy.

Roles of interferon regulatory factor 4 in the AKI-CKD transition, glomerular diseases and kidney allograft rejection

Interferon regulatory factor 4 (IRF4) is expressed in immune cells and is a member of the interferon regulatory factor family. Recently, it has been found that IRF4 plays important roles in the acute kidney injury (AKI)-chronic kidney disease (CKD) transition, glomerular diseases and kidney allograft rejection. In particular, the relationship between IRF4 and the AKI-CKD transition has attracted widespread attention. Furthermore, it was also found that the deficiency of IRF4 hindered the transition from AKI to CKD through the suppression of macrophage-to-fibroblast conversion, inhibition of M1-M2 macrophage polarization, and reduction in neutrophil inward flow. Additionally, an examination of the crucial role of IRF4 in glomerular disease was conducted. It was reported that inhibiting IRF4 could alleviate the progression of glomerular disease, and potential physiopathology mechanisms associated with IRF4 were postulated. Lastly, IRF4 was found to have detrimental effects on the development of antibody-mediated rejection (ABMR) and T-cell-mediated rejection (TCMR).

APC ameliorates idiopathic membranous nephropathy by affecting podocyte apoptosis through the ERK1/2/YB-1/PLA2R1 axis

Idiopathic membranous nephropathy (IMN) belongs to an important pathogenic category of adult nephrotic syndrome. PLA2R1 exposure is critical for triggering the pathogenesis of PLA2R1-related IMN. However, the pathogenesis of IMN and the molecular mechanism of treatment remain to be further clarified. The expression changes of activated protein C (APC) and PLA2R1 in IMN patients were quantified by qPCR. A zymosan activated serum (ZAS)-induced IMN podocyte model was established in vitro. Podocyte apoptosis was detected via flow cytometry and caspase‑3 assay. The expression levels of APC, p-ERK1/2, ERK1/2, YB-1 and PLA2R1 were detected by western blotting. The regulation relationship between YB-1 and PLA2R1 was detected by dual fluorescent reporter system. In IMN patients, the expression level of PLA2R1 was increased, whereas the expression level of APC was decreased. When APC was added to podocytes in vitro, the phosphorylation of ERK1/2 was increased, which could promote the translocation of YB-1 to the nucleus that reduces the expression of PLA2R1 at the cellular transcriptional level, thereby inhibiting podocyte apoptosis. Our study is the first to report that APC can improve membranous nephropathy by affecting podocyte apoptosis through the ERK1/2/YB-1/PLA2R1 axis. This study will provide a new targeted therapy for IMN patients with high PLA2R1 expression.

LncRNA SNHG1 knockdown inhibits hyperglycemia induced ferroptosis via miR-16-5p/ACSL4 axis to alleviate diabetic nephropathy

BACKGROUND

Hyperglycemia accelerates the development of diabetic nephropathy (DN) by inducing renal tubular injury. Nevertheless, the mechanism has not been elaborated fully. Here, the pathogenesis of DN was investigated to seek novel treatment strategies.

METHODS

A model of diabetic nephropathy was established in vivo, the levels of blood glucose, urine albumin creatinine ratio (ACR), creatinine, blood urea nitrogen (BUN), malondialdehyde (MDA), glutathione (GSH), and iron were measured. The expression levels were detected by qRT-PCR and Western blotting. H&E, Masson, and PAS staining were used to assess kidney tissue injury. The mitochondria morphology was observed by transmission electron microscopy (TEM). The molecular interaction was analyzed using a dual luciferase reporter assay.

RESULTS

SNHG1 and ACSL4 were increased in kidney tissues of DN mice, but miR-16-5p was decreased. Ferrostatin-1 treatment or SNHG1 knockdown inhibited ferroptosis in high glucose (HG)-treated HK-2 cells and in db/db mice. Subsequently, miR-16-5p was confirmed to be a target for SNHG1, and directly targeted to ACSL4. Overexpression of ACSL4 greatly reversed the protective roles of SNHG1 knockdown in HG-induced ferroptosis of HK-2 cells.

CONCLUSIONS

SNHG1 knockdown inhibited ferroptosis via the miR-16-5p/ACSL4 axis to alleviate diabetic nephropathy, which provided some new insights for the novel treatment of diabetic nephropathy.

Association of nocturia of self-report with estimated glomerular filtration rate: a cross-sectional study from the NHANES 2005-2018

Nocturia is a manifestation of systemic diseases, in which chronic kidney disease (CKD) is an independent predictor of nocturia due to its osmotic diuretic mechanism. However, to our knowledge, previous studies have not examined the association between nocturia and estimated glomerular filtration rate (eGFR). The purpose of this study was to assess the association between nocturia exposure and eGFR in the general US population. This study presents a cross-sectional analysis of the general US population enrolled in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. To account for potential confounding factors, linear regression analysis was conducted to investigate the association between nocturia and eGFR. Stratified analyses and interaction tests were employed to examine the variables of interest. Additionally, sensitivity analyses were conducted across diverse populations. A total of 12,265 individuals were included in the study. After controlling for confounding factors, the results of the linear regression analysis indicated that a single increase in nocturnal voiding frequency was associated with a decrease in eGFR by 2.0 mL/min/1.73 m2. In comparison to individuals with a nocturnal urinary frequency of 0, those who voided 1, 2, 3, 4, and ≥ 5 times at night experienced a decrease in eGFR by 3.1, 5.4, 6.4, 8.6 and 4.0 mL/min/1.73 m2, respectively. Nocturia was found to be associated with a decreased eGFR of 4 mL/min/1.73 m2 when compared to individuals without nocturia. The sensitivity analysis yielded consistent findings regarding the association between nocturia and eGFR in both CKD and non-CKD populations, as well as in hypertensive and non-hypertensive populations. Nevertheless, inconsistent conclusions were observed across various prognostic risk populations within the CKD context. The presence of nocturia and heightened frequency of nocturnal urination have been found to be associated with a decline in eGFR.

[Prognostic value of a predictive model comprising preoperative inflammatory response and nutritional indexes in patients with gastric cancer]

Objective: To investigate the prognostic value of preoperative inflammatory and nutritional condition detection in the postoperative survival, and establish a prognostic model for predicting the survival of patients with gastric cancer. Methods: The clinicopathological data of 1123 patients with gastric cancer who had undergone radical gastrectomy in Tianjin Medical University Cancer Institute & Hospital from January 2005 to December 2014 were retrospectively analyzed. Patients with history of other malignancy, with history of gastrectomy, who had received preoperative treatment, who died during the initial hospital stay or first postoperative month, and missing clinical and pathological information were excluded. Cox univariate and multivariate analyses were used to identify independent clinicopathological factors associated with the survival of these gastric cancer patients. Cox univariate analysis was used to identify preoperative inflammatory and nutritional indexes related to the survival of patients with gastric cancer after radical gastrectomy. Moreover, the Cox proportional regression model for multivariate survival analysis (forward stepwise regression method based on maximum likelihood estimation) was used. The independent clinicopathological factors that affect survival were incorporated into the following three new prognostic models: (1) an inflammatory model: significant preoperative inflammatory indexes identified through clinical and univariate analysis; (2) a nutritional model: significant preoperative nutritional indexes identified through clinical and univariate analysis; and (3) combined inflammatory/nutritional model: significant preoperative inflammatory and nutritional indexes identified through clinical and univariate analysis. A model that comprised only pT and pN stages in tumor TNM staging was used as a control model. The integrated area under the receiver operating characteristic curve (iAUC) and C-index were used to evaluate the discrimination of the model. Model fitting was evaluated by Akaike information criterion analysis. Calibration curves were used to assess agreement between the predicted probabilities and actual probabilities at 3-year or 5-year overall survival (OS). Results: The study cohort comprised 1 123 patients with gastric cancer. The mean age was 58.9±11.6 years, and 783 were males. According to univariate analysis, age, surgical procedure, extent of lymph node dissection, tumor location, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, and nerve invasion were associated with 5-year OS after radical gastrectomy for gastric cancer (all P<0.050). Multivariate analysis further identified age (HR: 1.18, 95%CI: 1.03-1.36, P=0.019), maximum tumor size (HR: 1.19, 95%CI: 1.03-1.38, P=0.022), number of examined lymph nodes (HR: 0.79, 95%CI: 0.68-0.92, P=0.003), pT stage (HR: 1.40, 95%CI: 1.26-1.55, P<0.001) and pN stage (HR: 1.28, 95%CI: 1.21-1.35, P<0.001) as independent prognostic factors for OS of gastric cancer patients. Additionally, according to univariate survival analysis, the preoperative inflammatory markers of neutrophil count, percentage of neutrophils, neutrophil/lymphocyte ratio, platelet/neutrophil ratio and preoperative nutritional indicators of serum albumin and body mass index were potential prognostic factors for gastric cancer (all P<0.05). On the basis of the above results, three models for prediction of prognosis were constructed. Variables included in the three models are as follows. (1) Inflammatory model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, percentage of neutrophils, and neutrophil-lymphocyte ratio; (2) nutritional model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, and serum albumin; and (3) combined inflammatory/nutritional model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, percentage of neutrophils, neutrophil-lymphocyte ratio, and serum albumin. We found that the predictive accuracy of the combined inflammatory/nutritional model, which incorporates both inflammatory indicators and nutrition indicators (iAUC: 0.676, 95% CI: 0.650-0.719, C-index: 0.698),was superior to that of the inflammation model (iAUC: 0.662, 95% CI: 0.673-0.706;C-index: 0.675), nutritional model (iAUC: 0.666, 95% CI: 0.642-0.698, C-index: 0.672), and TNM staging control model (iAUC: 0.676, 95% CI: 0.650-0.719, C-index: 0.658). Furthermore, the combined inflammatory/nutritional model had better fitting performance (AIC: 10 762) than the inflammatory model (AIC: 10 834), nutritional model (AIC: 10 810), and TNM staging control model (AIC: 10 974). Conclusions: Preoperative percentage of neutrophils, NLR, and BMI have predictive value for the prognosis of gastric cancer patients. The inflammatory / nutritional model can be used to predict the survival and prognosis of gastric cancer patients on an individualized basis.

DKK3 promotes oxidative stress injury and fibrosis in HK-2 cells by activating NOX4 via β-catenin/TCF4 signaling

Oxidative stress and fibrosis may accelerate the progression of chronic kidney disease (CKD). DKK3 is related to regulating renal fibrosis and CKD. However, the molecular mechanism of DKK3 in regulating oxidative stress and fibrosis during CKD development has not been clarified, which deserves to be investigated. Human proximal tubule epithelial cells (HK-2 cells) were treated with H₂O₂ to establish a cell model of renal fibrosis. The mRNA and protein expressions were analyzed using qRT-PCR and western blot, respectively. Cell viability and apoptosis were evaluated using MTT assay and flow cytometry, respectively. ROS production was estimated using DCFH-DA. The interactions among TCF4, β-catenin and NOX4 were validated using luciferase activity assay, ChIP and Co-IP. Herein, our results revealed that DKK3 was highly expressed in HK-2 cells treated with H₂O₂. DKK3 depletion increased H₂O₂-treated HK-2 cell viability and reduced cell apoptosis, oxidative stress, and fibrosis. Mechanically, DKK3 promoted formation of the β-catenin/TCF4 complex, and activated NOX4 transcription. Upregulation of NOX4 or TCF4 weakened the inhibitory effect of DKK3 knockdown on oxidative stress and fibrosis in H₂O₂-stimulated HK-2 cells. All our results suggested that DKK3 accelerated oxidative stress and fibrosis through promoting β-catenin/TCF4 complex-mediated activation of NOX4 transcription, which could lead to novel molecules and therapeutic targets for CKD.

Shear Wave Elastography for Assessment of Biopsy-Proven Renal Fibrosis: A Systematic Review and Meta-analysis

The purpose of this meta-analysis was to evaluate the diagnostic performance of shear wave elastography (SWE) for the staging of renal fibrosis in patients with chronic kidney disease (CKD). Classification of CKD into mild, moderate and severe fibrosis was based on renal biopsy pathology (glomerulosclerosis, tubulointerstitial injury and vascular sclerosis). The Cochrane Library, Medline, PubMed, Web of Science, EMBASE and CNKI databases were searched from January 1, 2009, to April 20, 2022. Pooled sensitivity, specificity, diagnostic odds ratio and area under the receiver operating characteristic curve (AUROC) were calculated using random effects models. A total of 1394 patients from 14 studies were included in the final analysis. For mild, moderate and severe renal fibrosis, SWE had a sensitivity of 0.79 (95% confidence interval [CI]: 0.67-0.88), 0.73 (95% CI: 0.65-0.80) and 0.87 (95% CI: 0.71-0.95); a specificity of 0.82 (95% CI: 0.75-0.87), 72% (95% CI: 0.67-0.77) and 0.83 (95% CI: 0.80-0.86); an AUROC of 0.87 (95% CI: 0.84-0.90), 0.78 (95% CI: 0.75-0.82) and 0.86 (95% CI: 0.82-0.88); and a diagnostic odds ratio of 17 (95% CI: 7-43), 7 (95% CI: 4-12) and 34 (95% CI: 13-88), respectively. Meta-regressions revealed that the publication date, system used and number of valid measurements of SWE were the main causes of heterogeneity. SWE is a good technique for diagnosing mild and severe renal fibrosis, as well as a fair technique for diagnosing moderate fibrosis.

MiR-449a downregulation alleviates the progression of renal interstitial fibrosis by mediating the KLF4/MFN2 axis

BACKGROUND

Renal interstitial fibrosis (RIF) seriously threatens the health of individuals. MiRNAs regulate the progression of fibrosis. Nevertheless, the detailed function of miR-449a in RIF is largely unknown.

METHODS

In vitro and in vivo models of RIF were developed to evaluate the function of miR-449a. The relationship among miR-449a, KLF4, and MFN2 was explored using a dual-luciferase reporter assay and chromatin immunoprecipitation. Additionally, the pathological changes in the mice were detected using Masson staining. The mRNA and protein expressions were assessed using quantitative reverse transcription polymerase chain reaction and western blot, respectively.

RESULTS

TGF-β1 downregulated the expressions of KLF4 and MFN2 in TCMK-1 cells, but upregulated the level of miR-449a. The downregulation of miR-449a significantly inhibited TGF-β1-induced upregulation of fibrotic proteins in TCMK-1 cells. Meanwhile, miR-449a directly targeted KLF4. Moreover, KLF4 overexpression activated MFN2 transcription and reversed TGF-β1-induced fibrosis by positively regulating MFN2. Furthermore, the downregulation of miR-449a could obviously alleviate the symptoms of RIF in mice with unilateral ureteral obstruction.

CONCLUSION

MiR-449a downregulation attenuated the development of RIF by mediating the KLF4/MFN2 axis. Therefore, miR-449a might act as a target in treating RIF.

Identification of immune-related molecular clusters and diagnostic markers in chronic kidney disease based on cluster analysis

Background: Chronic kidney disease (CKD) is a heterogeneous disease with multiple etiologies, risk factors, clinical manifestations, and prognosis. The aim of this study was to identify different immune-related molecular clusters in CKD, their functional immunological properties, and to screen for promising diagnostic markers. Methods: Datasets of 440 CKD patients were obtained from the comprehensive gene expression database. The core immune-related genes (IRGs) were identified by weighted gene co-expression network analysis. We used unsupervised clustering to divide CKD samples into two immune-related subclusters. Then, functional enrichment analysis was performed for differentially expressed genes (DEGs) between clusters. Three machine learning methods (LASSO, RF, and SVM-RFE) and Venn diagrams were applied to filter out 5 significant IRGs with distinguished subtypes. A nomogram diagnostic model was developed, and the prediction effect was verified using calibration curve, decision curve analysis. CIBERSORT was applied to assess the variation in immune cell infiltration among clusters. The expression levels, immune characteristics and immune cell correlation of core diagnostic markers were investigated. Finally, the Nephroseq V5 was used to assess the correlation among core diagnostic markers and renal function. Results: The 15 core IRGs screened were differentially expressed in normal and CKD samples. CKD was classified into two immune-related molecular clusters. Cluster 2 is significantly enriched in biological functions such as leukocyte adhesion and regulation as well as immune activation, and has a severe immune prognosis compared to cluster 1. A nomogram diagnostic model with reliable prediction of immune-related clusters was developed based on five signature genes. The core diagnostic markers LYZ, CTSS, and ISG20 were identified as playing an important role in the immune microenvironment and were shown to correlate meaningfully with immune cell infiltration and renal function. Conclusion: Our study identifies two subtypes of CKD with distinct immune gene expression patterns and provides promising predictive models. Along with the exploration of the role of three promising diagnostic markers in the immune microenvironment of CKD, it is anticipated to provide novel breakthroughs in potential targets for disease treatment.

MG53: A potential therapeutic target for kidney disease

Ensuring cell survival and tissue regeneration by maintaining cellular integrity is important to the pathophysiology of many human diseases, including kidney disease. Mitsugumin 53 (MG53) is a member of the tripartite motif-containing (TRIM) protein family that plays an essential role in repairing cell membrane injury and improving tissue regeneration. In recent years, an increasing number of studies have demonstrated that MG53 plays a renoprotective role in kidney diseases. Moreover, with the beneficial effects of the recombinant human MG53 (rhMG53) protein in the treatment of kidney diseases in different animal models, rhMG53 shows significant therapeutic potential in kidney disease. In this review, we elucidate the role of MG53 and its molecular mechanism in kidney disease to provide new approaches to the treatment of kidney disease.

Alterations of amplitude of low-frequency fluctuations and fractional amplitude of low-frequency fluctuations in end-stage renal disease on maintenance dialysis: An activation likelihood estimation meta-analysis

BACKGROUND

Cognitive impairment (CI) is a common complication of end-stage renal disease (ESRD). Many resting-state functional magnetic resonance imaging (rs-fMRI) studies have identified abnormal spontaneous low-frequency brain activity in ESRD dialysis patients. However, these studies have reported inconsistent results. So far, no meta-analyses on this topic have been published. This meta-analysis aimed to identify the more consistently vulnerable brain regions in ESRD patients at rest and to reveal its possible neuropathophysiological mechanisms.

METHODS

We systematically searched PubMed, Cochrane Library, Web of Science, Medline, and EMBASE databases up to July 20, 2022 based on the amplitude of low-frequency fluctuation (ALFF) or fractional amplitude of low-frequency fluctuation (fALFF). Brain regions with abnormal spontaneous neural activity in ESRD compared to healthy controls (HCs) from previous studies were integrated and analyzed using an activation likelihood estimation (ALE) method. Jackknife sensitivity analysis was carried out to assess the reproducibility of the results.

RESULTS

In total, 11 studies (380 patients and 351 HCs) were included in the final analysis. According to the results of the meta-analysis, compared with HCs, ESRD patients had decreased ALFF/fALFF in the right precuneus, right cuneus, and left superior temporal gyrus (STG), while no brain regions with increased brain activity were identified. Jackknife sensitivity analysis showed that our results were highly reliable.

CONCLUSION

Compared to HCs, ESRD dialysis patients exhibit significant abnormalities in spontaneous neural activity associated with CI, occurring primarily in the default mode network, visual recognition network (VRN), and executive control network (ECN). This contributes to the understanding of its pathophysiological mechanisms.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42022348694].

Clinical study on the use of advanced magnetic resonance imaging in lupus nephritis

OBJECTIVES

To investigate the correlation between the histopathology of the kidney and clinical indicators in patients with lupus nephritis (LN) using magnetic resonance imaging (MRI).

METHODS

A total 50 female participants were enrolled in the study. Thirty patients with LN were divided into types 2, 3, 4, and 5, according to their pathological features. The control group consisted of 20 healthy female volunteers. Serum creatinine, C3, C1q, and anti-ds-DNA were measured. Conventional MRI, DTI, DWI, and BOLD scanning was performed to obtain the FA, ADC, and R2* values for the kidney.

RESULTS

Compared with the control group, FA and the ADC were decreased in patients with LN, while the R2* value was increased (P < 0.05). The overall comparison of the SLEDAI (Activity index of systemic lupus erythematosus) score, total pathological score, AI, and serum creatinine C3 showed that these were significantly different between the two groups (P < 0.05). FA and the ADC were negatively correlated with urinary, blood ds-DNA, and serum creatinine and positively correlated with C1q (P < 0.05). The R2* value was positively correlated with urinary NGAL, blood ds-DNA, and serum creatinine (P < 0.05). FA and the ADC were negatively correlated with the SLEDAI score, total pathological score, AI, CI, nephridial tissue C3, and C1q. The R2* value was positively correlated with the SLEDAI score, total pathological score, AI, CI, nephridial tissue C3, and C1q (P < 0.05).

CONCLUSIONS

MRI examination in female patients with LN was correlated with pathologic test results, which may have clinical significance in determining the disease's severity, treatment, and outcome.

Ion channels as a therapeutic target for renal fibrosis

Renal ion channel transport and electrolyte disturbances play an important role in the process of functional impairment and fibrosis in the kidney. It is well known that there are limited effective drugs for the treatment of renal fibrosis, and since a large number of ion channels are involved in the renal fibrosis process, understanding the mechanisms of ion channel transport and the complex network of signaling cascades between them is essential to identify potential therapeutic approaches to slow down renal fibrosis. This review summarizes the current work of ion channels in renal fibrosis. We pay close attention to the effect of cystic fibrosis transmembrane conductance regulator (CFTR), transmembrane Member 16A (TMEM16A) and other Cl− channel mediated signaling pathways and ion concentrations on fibrosis, as well as the various complex mechanisms for the action of Ca2+ handling channels including Ca2+-release-activated Ca2+ channel (CRAC), purinergic receptor, and transient receptor potential (TRP) channels. Furthermore, we also focus on the contribution of Na+ transport such as epithelial sodium channel (ENaC), Na+, K+-ATPase, Na+-H+ exchangers, and K+ channels like Ca2+-activated K+ channels, voltage-dependent K+ channel, ATP-sensitive K+ channels on renal fibrosis. Proposed potential therapeutic approaches through further dissection of these mechanisms may provide new therapeutic opportunities to reduce the burden of chronic kidney disease.

Three-dimensional building morphology impacts on PM2.5 distribution in urban landscape settings in Zhejiang, China

Three-dimensional (3D) urban landscape patterns and building morphology are crucial for urban planning and essential for urban landscape functions. In this study, fixed and mobile monitoring sites were used to determine the spatial distribution of PM_2.5 concentrations in Hangzhou. Six 3D metrics were selected to analyze the response of PM_2.5 pollution to landscape patterns and building morphology, while their two-dimensional (2D) counterparts' metrics were also analyzed to contrast the differences. A variance partitioning analysis (VPA) was performed to measure the combined and relative contribution of 3D and 2D metrics to the changes in PM_2.5 concentrations. The results showed that: (1) on the 3D scale, forming a building pattern with a combination of different building heights can eliminate the accumulation of PM_2.5; (2) on the 2D scale, fragmentation and decentralization of landscapes and building patches alleviate PM_2.5 pollution; and (3) 3D building morphology indicators have the highest explanatory power (40.94%) for the changes of PM_2.5 concentrations. It turns out that the explanatory power of 3D metrics for PM_2.5 concentrations changes is much greater than that of 2D metrics. In addition, when compared to building morphology indicators from a single dimension, the combination of 2D and 3D metrics is better able to reflect urban PM_2.5 pollution. The results of this study expand our understanding of how PM_2.5 pollution responds to 2D and 3D metrics and provide useful information for urban planning.

circPlekha7 suppresses renal fibrosis via targeting miR-493-3p/KLF4

Aims: The authors aim to investigate the function of circPlekha7 in renal fibrosis. Methods: Human renal tissues from chronic kidney disease patients, kidney cell line and primary cultured renal tubular epithelial cells were used. TGF-β1-treated human kidney 2 cells/tubular epithelial cells and a unilateral ureteral obstruction mouse model were employed to study renal fibrosis. Results: circPlekha7 was diminished in renal tissues from chronic kidney disease patients and TGF-β1-treated human kidney 2 cells and tubular epithelial cells, while miR-493-3p was upregulated. Overexpression of circPlekha7 or knockdown of miR-493-3p suppressed TGF-β1 induced enhancements on epithelial to mesenchymal transition and fibrogenesis, as well as attenuated renal fibrosis and injury in mice subjected to unilateral ureteral obstruction. circPlekha7 bound with miR-493-3p, which directly targeted KLF4. Conclusion: circPlekha7 inhibits epithelial to mesenchymal transition of renal tubular epithelial cells and fibrosis via targeting miR-493-3p to de-repress KLF4/mitofusin2 expression.

Dickkopf-3: Current Knowledge in Kidney Diseases

Dickkopf-related protein 3 (DKK3) is a secreted glycoprotein that has been implicated in the pathogenesis of a variety of diseases. Recent evidence suggests that urinary DKK3 may serve as a potential biomarker for monitoring kidney disease progression and assessing the effects of interventions. We review the biological role of DKK3 as an agonist in chronic kidney disease (CKD) and autosomal dominant polycystic kidney disease (ADPKD) and as an antagonist in idiopathic membranous nephropathy (IMN). In addition, we present the clinical applications of DKK3 in acute kidney disease and tubulointerstitial fibrosis, suggesting that urine DKK3 may be a potential biomarker for acute kidney disease and CKD. Further research into the mechanism of DKK3 and its use as a diagnostic tool, alone or in combination with other biomarkers, could prove clinically useful for better understanding the pathology of kidney diseases and improving early detection and treatment.

Overexpression of UBE2C correlates with poor prognosis in gastric cancer patients

OBJECTIVE

The ubiquitin-conjugating enzyme E2C (UBE2C) has been known as a crucial factor upregulated in various tumors. The functions of UBE2C is mainly involved in the pathway protein ubiquitination. This study investigates the expression of UBE2C in gastric cancers and its correlation with overall survival rate.

MATERIALS AND METHODS

Real-time PCR (RT-PCR) and Western blotting were performed to determine the expression of UBE2C in gastric cancer samples and adjacent normal tissues. Immunohistochemical staining was used to assess the expression of UBE2C in 216 paraffin-embedded gastric cancer tissues.

RESULTS

The mRNA and relevant protein levels of UBE2C in gastric cancer tissues are significantly greater than those in the adjacent normal tissues. Also, the expression of UBE2C is found to correlate with lymphatic metastasis, serosa invasion, TNM (Malignant Tumors) staging and Lauren's classification (p<0.05). The univariate analysis shows that the overexpression of UBE2C associates with poor prognosis (p=0.001). The multivariate analysis demonstrates that expression of UBE2C, lymphatic metastasis, and TNM staging are independent prognostic indicators.

CONCLUSIONS

This study shows that overexpression of UBE2C contributes to the development of gastric cancer, and UBE2C has the potential to be exploited as a therapeutic target.

Inhibition of HDAC6 activity in kidney diseases: a new perspective

Histone deacetylase 6 (HDAC6), a cytoplasmic enzyme that plays important roles in many biological processes, is one isoform of a family of HDAC enzymes that catalyse the removal of functional acetyl groups from proteins. HDAC6 stands out from the other members of this family because it almost exclusively deacetylates cytoplasmic proteins and exerts deacetylation-independent effects, which has led to the successful development of relatively isoform-specific inhibitors of its enzymatic action. Numerous studies have recently demonstrated that HDAC6 expression and activity are increased in kidney disease, such as autosomal dominant polycystic kidney disease (ADPKD), renal fibrosis, and acute kidney injury (AKI), among others. Moreover, HDAC6 inhibitors have been investigated for use in treating these diseases. In fact, HDAC6 inhibitors effectively limit the progression of kidney diseases, suggesting that targeting HDAC6 may provide a novel treatment approach. However, the primary challenge in developing HDAC6-targeted therapies is understanding how the renoprotective effect of NDAC6 inhibitors can be selectively harnessed. Here, we discuss the unique function of HDAC6 and recapitulate the alluring potential of its inhibitors in kidney diseases.

The Role of Y-Box Binding Protein 1 in Kidney Injury: Friend or Foe?

Y-box-binding protein 1 (YB-1) is a multifunctional protein involved in various cellular processes via the transcriptional and translational regulation of target gene expression. YB-1 promotes acute or chronic kidney injury through multiple molecular pathways; however, accumulating evidence suggests that significantly increased YB-1 levels are of great importance in renoprotection. In addition, YB-1 may contribute to obesity-related kidney disease by promoting adipogenesis. Thus, the role of YB-1 in kidney injury is complicated, and no comprehensive review is currently available. In this review, we summarise recent progress in our understanding of the function of YB-1 in kidney injury and provide an overview of the dual role of YB-1 in kidney disease. Moreover, we propose that YB-1 is a potential therapeutic target to restrict kidney disease.

Overexpression of UBE2C correlates with poor prognosis in gastric cancer patients

OBJECTIVE

The ubiquitin-conjugating enzyme E2C (UBE2C) has been known as a crucial factor upregulated in various tumors. The functions of UBE2C is mainly involved in the pathway protein ubiquitination. This study investigates the expression of UBE2C in gastric cancers and its correlation with overall survival rate.

MATERIALS AND METHODS

Real-time PCR (RT-PCR) and Western blotting were performed to determine the expression of UBE2C in gastric cancer samples and adjacent normal tissues. Immunohistochemical staining was used to assess the expression of UBE2C in 216 paraffin-embedded gastric cancer tissues.

RESULTS

The mRNA and relevant protein levels of UBE2C in gastric cancer tissues are significantly greater than those in the adjacent normal tissues. Also, the expression of UBE2C is found to correlate with lymphatic metastasis, serosa invasion, TNM (Malignant Tumors) staging and Lauren's classification (p<0.05). The univariate analysis shows that the overexpression of UBE2C associates with poor prognosis (p=0.001). The multivariate analysis demonstrates that expression of UBE2C, lymphatic metastasis, and TNM staging are independent prognostic indicators.

CONCLUSIONS

This study shows that overexpression of UBE2C contributes to the development of gastric cancer, and UBE2C has the potential to be exploited as a therapeutic target.

α-klotho and anemia in patients with chronic kidney disease patients: A new perspective

Normocytic normochromic anemia is a common complication of chronic kidney disease (CKD) and is associated with numerous adverse consequences. Certain symptoms previously attributed to CKD are now known to be a consequence of anemia. Anemia contributes to an increased cardiac output, and the development of left ventricular hypertrophy, angina and congestive heart failure, leading to high morbidity and mortality in patients with CKD. The multifunctional α-klotho (KL) protein, which is predominantly expressed in the kidneys, is associated with the occurrence of anemia in patients with CKD. The present review presents current evidence on the potential role of α-KL in renal anemia. Low expression of α-KL appears to improve anemia in patients with CKD, and has been hypothesized to be a compensatory mechanism to attenuate the effects of anemia in patients with CKD. Further understanding of the role of α-KL in renal anemia may offer novel insights into the treatment of patients with CKD complicated with anemia.

Effects of caloric restriction on peroxisome proliferator-activated receptors and positive transcription elongation factor b expression in obese rats

OBJECTIVE

To investigate the effect of caloric restriction (CR) on expressions of peroxisome proliferators-activated receptors (PPARs) and positive transcription elongation factor b (P-TEFb) (including cyclin-dependent kinase 9 (CDK9) and cyclin T1) protein in visceral adipose tissue of obese rats.

MATERIALS AND METHODS

Obese rats were induced by high-fat diet for 8 weeks. Then they were divided into three groups: Model (n=5), 50% Calorie Restricted (50% CR, n=5), Intermittent Fasting (IF) (eight cycles of 3-d fasting and 3-d refeeding, n=6) for 8 weeks. Biochemical parameters were measured. Protein and mRNA expression of Cdk9, cyclin T1 and PPARs were qualified in visceral adipose tissue.

RESULTS

A significant decline in fasting plasma glucose (FPG), homeostatic model assessment of insulin resistance (HOMA-IR), body weight, and visceral fat weight was observed in 50% CR group. The IF group exhibited a significant decrease in FPG, HOMA-IR, visceral fat weight. Both 50% CR and IF down-regulated mRNA and protein expression of PPARγ and Cdk9, cyclin T1 and up-regulated mRNA and protein expression of PPARβ.

CONCLUSIONS

These results suggest that the effects of 50% CR and IF on HOMA-IR, body weight, visceral fat weight, P-TEFb and PPARγ expression may be related to their protective potential on obesity.

The NLPR3 inflammasome and obesity-related kidney disease

Over the past decade, the prevalence of obesity has increased, accompanied by a parallel increase in the prevalence of chronic kidney disease (CKD). Mounting evidence suggests that high body mass index (BMI) and obesity are important risk factors for CKD, but little is known about the mechanisms of obesity‐related kidney disease (ORKD). The NLRP3 inflammasome is a polyprotein complex that plays a crucial role in the inflammatory process, and numerous recent studies suggest that the NLRP3 inflammasome is involved in ORKD development and may serve as a key modulator of ORKD. Moreover, inhibiting activation of the NLRP3 inflammasome has been shown to attenuate ORKD. In this review, we summarize recent progress in understanding the link between the NLRP3 inflammasome and ORKD and discuss targeting the NLRP3 inflammasome as a novel therapeutic approach for ORKD.

Targeted inhibition of endoplasmic reticulum stress: New hope for renal fibrosis (Review)

Chronic kidney disease (CKD) has a very high mortality rate and remains a global health challenge. Inhibiting renal fibrosis is one of the most promising therapeutic strategies for CKD. Recent studies have indicated that endoplasmic reticulum stress (ERS) serves an active role in the development of acute and chronic kidney disease, especially with regards to renal fibrosis. In the current review, the authors summarize the latest understanding of the role of ERS during the onset of renal fibrosis. ERS promotes renal fibrosis through multiple signaling pathways, such as transforming growth factor-β, epithelial-mesenchymal transition and oxidative stress. In addition, ERS also causes podocyte damage, leading to increased proteinuria and the development of renal fibrosis in rat models. In conclusion, targeted inhibition of ERS may become a promising therapeutic strategy for renal fibrosis.

Matrix Metalloproteinases-7 and Kidney Fibrosis

Matrix metalloproteinase-7 (MMP-7) is a secreted zinc- and calcium-dependent endopeptidase that degrades a broad range of extracellular matrix substrates and additional substrates. MMP-7 playsa crucial role in a diverse array of cellular processes and appears to be a key regulator of fibrosis in several diseases, including pulmonary fibrosis, liver fibrosis, and cystic fibrosis. In particular, the relationship between MMP-7 and kidney fibrosis has attracted significant attention in recent years. Growing evidence indicates that MMP-7 plays an important role in the pathogenesis of kidney fibrosis. Here, we summarize the recent progress in the understanding of the role of MMP-7 in kidney fibrosis. In particular, we discuss how MMP-7 contributes to kidney fibrotic lesions via the following three pathways: epithelial-mesenchymal transition (EMT), transforming growth factor-beta (TGF-β) signaling, and extracellular matrix (ECM) deposition. Further dissection of the crosstalk among and regulation of these pathways will help clinicians and researchers develop effective therapeutic approaches for treating chronic kidney disease.

The Role of Krüppel-like Factor 4 in Renal Fibrosis

Chronic kidney disease (CKD) caused by renal fibrosis is an important public health concern. It is therefore necessary to understand the molecular pathogenesis of renal fibrosis in order to develop novel therapeutic strategies. KLF4 is the most extensively studied factor among the various members of the Krüppel-like factor (KLF) family of zinc finger-containing transcription factors. Many studies have demonstrated that KLF4 inhibits the activation of myofibroblasts and exerts an inhibitory effect on fibrosis. However, other studies have indicated that KLF4 may promote renal fibrosis. These controversial results suggest that KLF4 may be crucially involved in the development of renal fibrosis, although the underlying mechanism(s) remain unclear. Here, we summarize the recent progress made in understanding the role of KLF4 in renal fibrosis. Together, these findings suggest that KLF4 may participate in the development of renal fibrosis, but that its inhibition of fibrosis is greater than its promotion of the condition, which suggests that KLF4 may serve as a novel therapeutic target for renal fibrosis.

Disruption of Type-I IFN pathway ameliorates preservation damage in mouse orthotopic liver transplantation via HO-1 dependent mechanism

Ischemia/reperfusion injury (IRI) remains unresolved problem in clinical organ transplantation. We analyzed the role of Type-I interferon (IFN) pathway in a clinically relevant murine model of extended hepatic cold preservation followed by orthotopic liver transplantation (OLT). Livers from Type-I IFN receptor (IFNAR) knockout (KO) or wild-type (WT) mice (C57/BL6) were harvested, preserved at 4°C in UW solution for 20 h and transplanted to groups of syngeneic IFNAR KO or WT recipients. Liver graft but not recipient IFNAR deficiency was required to consistently ameliorate IRI in OLTs. Indeed, disruption of Type-I IFN signaling decreased serum alanine aminotransferase (sALT) levels (p < 0.001), diminished Suzuki's score of histological OLT damage (p < 0.01) and improved 14-day survival (from 42%[5/12] in WT to 92%[11/12] in IFNAR KO; p < 0.05). Unlike in WT group, IFNAR deficiency attenuated OLT expression of TNF-α, IL-1β, IL-6, MCP-1, CXCL-10, ICAM-1; diminished infiltration by macrophages/PMNs; and enhanced expression of antioxidant HO-1/Nrf2. The frequency of TUNEL+ apoptotic cells and caspase-3 activity/expression selectively decreased in IFNAR KO group. Small interfering (si)RNA-directed targeting of HO-1 restored cardinal features of liver IRI in otherwise resistant IFNAR-deficient OLTs. Thus, intact Type-I IFN signaling is required for hepatic IRI, whereas HO-1 is needed for cytoprotection against innate immunity-dominated organ preservation damage in IFNAR-deficient liver transplants.

Sotrastaurin, a protein kinase C inhibitor, ameliorates ischemia and reperfusion injury in rat orthotopic liver transplantation

Sotraustaurin (STN), a small molecule, targeted protein kinase C (PKC) inhibitor that prevents T-lymphocyte activation via a calcineurin-independent pathway, is currently being tested in Phase II renal and liver transplantation clinical trials. We have documented the key role of activated T cells in the inflammation cascade leading to liver ischemia/reperfusion injury (IRI). This study explores putative cytoprotective functions of STN in a clinically relevant rat model of hepatic cold ischemia followed by orthotopic liver transplantation (OLT). Livers from Sprague-Dawley rats were stored for 30 h at 4°C in UW solution, and then transplanted to syngeneic recipients. STN treatment of liver donors/recipients or recipients only prolonged OLT survival to >90% (vs. 40% in controls), decreased hepatocellular damage and improved histological features of IRI. STN treatment decreased activation of T cells, and diminished macrophage/neutrophil accumulation in OLTs. These beneficial effects were accompanied by diminished apoptosis, NF-κB/ERK signaling, depressed proapoptotic cleaved caspase-3, yet upregulated antiapoptotic Bcl-2/Bcl-xl and hepatic cell proliferation. In vitro, STN decreased PKCθ/IκBα activation and IL-2/IFN-γ production in ConA-stimulated spleen T cells, and diminished TNF-α/IL-1β in macrophage-T cell cocultures. This study documents positive effects of STN on liver IRI in OLT rat model that may translate as an additional benefit of STN in clinical liver transplantation.

Interaction between the intermediary electron acceptor (pheophytin) and a possible plastoquinone-iron complex in photosystem II reaction centers

Photoreduction of the intermediary electron acceptor, pheophytin (Pheo), in photosystem II reaction centers of spinach chloroplasts or subchloroplast particles (TSF-II and TSF-IIa) at 220 K and redox potential E(h) = -450 mV produces an EPR doublet centered at g = 2.00 with a splitting of 52 G at 7 K in addition to a narrow signal attributed to Pheo([unk]) (g = 2.0033, DeltaH approximately 13 G). The doublet is eliminated after extraction of lyophilized TSF-II with hexane containing 0.13-0.16% methanol but is restored by reconstitution with plastoquinone A (alone or with beta-carotene) although not with vitamin K(1). TSF-II and TSF-IIa are found to contain approximately 2 nonheme Fe atoms per reaction center. Incubation with 0.55 M LiClO(4) plus 2.5 mM o-phenanthroline (but not with 0.55 M LiClO(4) alone) decreases this value to approximately 0.6 and completely eliminates the EPR doublet, but photoreduction of Pheo is not significantly affected. Partial restoration of the doublet (about 25%) was achieved by subsequent incubation with 0.2 mM Fe(2+), but not with either Mn(2+) or Mg(2+). The Fe removal results in the development of a photoinduced EPR signal (g = 2.0044 +/- 0.0003, DeltaH = 9.2 +/- 0.5 G) at E(h) = 50 mV, which is not observed after extraction with 0.16% methanol in hexane. It is ascribed to plastosemiquinone no longer coupled to Fe in photosystem II reaction centers. The results show that a complex of plastoquinone and Fe can act as the stable "primary" electron acceptor in photosystem II reaction centers and that the interaction of its singly reduced form with the reduced intermediary acceptor, Pheo([unk]), is responsible for the EPR doublet.

Redox titration of fluorescence yield of photosystem II

The variable fluorescence yield of photosystem II is dependent on the redox state of the fluorescence quencher molecule or the primary electron acceptor of the system. We have carried out redox titrations of fluorescence yield of a photochemically active photosystem-II reaction-center particle and have measured the redox potential of the photosystem-II primary acceptor.During reductive titrations using dithionite as the reductant, only a single quenching transition was observed. For instance, at pH 7.0, the midpoint potential of the fluorescence transition is -325 mV, and those at a pH between 6.0 and 7.5 are consistent with a pH dependence of about 60 mV/pH unit. At a given pH, the midpoint potential of the transition closely corresponds to that of the most negative transition previously measured in unfractionated chloroplasts (both by chemical reductive titration). Oxidative titrations using ferricyanide as the oxidant yielded hysteresis in the titration curves.Similar changes in fluorescence yield were observed in redox titrations by electrochemical reduction or oxidation. Electrochemical reductive and oxidative titrations yielded reversible transitions, contrary to the hysteresis observed during chemical oxidative titration. From coulometric-titration data, we have estimated that most likely one electron is involved in the redox transition of the fluorescence-quencher or primary-electron-acceptor molecule of photosystem II. These findings are consistent with the current proposal that a membrane-bound plastoquinone functions as the primary acceptor of photosystem II.

Spectral and kinetic evidence for two early electron acceptors in photosystem I

Triton-fractionated photosystem-I particles poised at -625 mV, where the two bound iron-sulfur proteins are reduced, have been studied by optical and electron paramagnetic resonance spectroscopies from 293 to 5 K. At 5-9 K, these particles exhibit two decay components with lifetimes of 1.3 and 130 msec in the laser pulse-induced absorption and electron paramagnetic resonance signal changes. Spectral properties of the 130-msec decay component reflect the charge separation between P-700 and some iron-sulfur center having a broad optical absorbance in the 400- to 550-nm region and a previously reported electron paramagnetic resonance signal with g = 1.78, 1.88, and 2.08. Spectral properties of the 1-msec decay component indicate photoinduced charge separation between P-700 and a chlorophyll a dimer having absorption bands at 420, 450, and 700 nm. It is assumed that these two acceptors participate in the electron transfer from P-700(*) to the bound iron-sulfur proteins.

Oxidation-reduction potentials of bound iron-sulfur proteins of photosystem I

Digitonin - fractionated photosystem - I subchloroplasts were titrated potentiometrically between -450 and -610 mV at pH 10. Examination of the titrated subchloroplasts by low-temperature (13 degrees K) electron paramagnetic resonance spectroscopy revealed resonances centered at values of 2.05, 1.94, 1.92, 1.89, and 1.86 on the g-factor scale. The peak heights depended on the potentials at which the chloroplasts were poised. The resonances of at least three iron-sulfur centers can be recognized: one with lines at g = 2.05 and 1.94; one with lines at g = 2.05, 1.92, and 1.89; and one for which only a line at g = 1.86 has been resolved. The midpoint potentials of the iron-sulfur species fall into two distinctly separate regions: the titration profile of the g = 1.94 signal, the first segment of the g = 2.05 plot, and the rise phase of the g = 1.86 signal had a value of -530 +/- 5 mV; the upper segment of the g = 2.05 plot, the decrease phase of the g = 1.86 signal, and the g = 1.89 profile had a midpoint potential estimated to be [unk] -580 mV. The oxidation-reduction reaction of each of the bound iron-sulfur species, as represented by the changes of the electron paramagnetic resonance spectra, was reversible and apparently involved a two-electron change.Titration at pH 9 could only be carried to -560 mV, and essentially only the first half of the titration behavior as found at pH 10 was seen. At any given potential more positive than -560 mV, the part of the iron-sulfur protein that was not reduced electrochemically could be reduced photochemically, but only to the maximum extent reduced electrochemically at -560 mV. Whereas, chloroplasts illuminated at room temperature and then frozen while still being illuminated developed a signal similar to that produced by electrochemical reduction at -610 mV, illumination at 77 degrees K did not bring about photoreduction beyond that accomplished electrochemically at about -560 mV.Dithionite alone in the dark and under anaerobic conditions brought about a partial reduction to the extent of the first electrochemical reduction step. Dithionite plus illumination at room temperature or dithionite plus methyl viologen in the dark produced the maximum signal. Electron paramagnetic resonance spectra due to either light or electrochemically reduced iron-sulfur proteins showed no detectable decay for at least 3 days when samples were stored in the dark at 77 degrees K.