Oxidative Stress Genes in Diabetes Mellitus Type 2: Association with Diabetic Kidney Disease

Advances in Traditional Chinese Medicine research in diabetic kidney disease treatment

CONTEXT

Diabetic kidney disease (DKD) is a prominent complication arising from diabetic microangiopathy, and its prevalence and renal impact have placed it as the primary cause of end-stage renal disease. Traditional Chinese Medicine (TCM) has the distinct advantage of multifaceted and multilevel therapeutic attributes that show efficacy in improving clinical symptoms, reducing proteinuria, protecting renal function, and slowing DKD progression. Over recent decades, extensive research has explored the mechanisms of TCM for preventing and managing DKD, with substantial studies that endorse the therapeutic benefits of TCM compounds and single agents in the medical intervention of DKD.

OBJECTIVE

This review lays the foundation for future evidence-based research efforts and provide a reference point for DKD investigation.

METHODS

The relevant literature published in Chinese and English up to 30 June 2023, was sourced from PubMed, Cochrane Library, VIP Database for Chinese Technical Periodicals (VIP), Wanfang Data, CNKI, and China Biology Medicine disc (CBM). The process involved examining and summarizing research on TCM laboratory tests and clinical randomized controlled trials for DKD treatment.

RESULTS AND CONCLUSIONS

The TCM intervention has shown the potential to inhibit the expression of inflammatory cytokines and various growth factors, lower blood glucose levels, and significantly affect insulin resistance, lipid metabolism, and improved renal function. Furthermore, the efficacy of TCM can be optimized by tailoring personalized treatment regimens based on the unique profiles of individual patients. We anticipate further rigorous and comprehensive clinical and foundational investigations into the mechanisms underlying the role of TCM in treating DKD.

RBM15 Promotes High Glucose-Induced Lens Epithelial Cell Injury by Inducing PRNP N6-Methyladenine Modification During Diabetic Cataract

PURPOSE

Diabetic cataract (DC) is a major cause of blindness worldwide. Prion protein (PRNP) was proved to be up-regulated and hypomethylated in DC samples. Here, we investigated whether PRNP was involved in DC progression in N6-methyladenosine (m6A)-dependent manner, and its potential mechanisms.

METHODS

Levels of genes and proteins were assayed using qRT-PCR and western blotting. Cell proliferation and apoptosis were determined using Cell Counting Kit-8 assay, 5-thynyl-2'-deoxyuridine (EdU) assay, and flow cytometry, respectively. Oxidative stress was analyzed by measuring the production of glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), and malondialdehyde (MDA). The m6A modification was determined by RNA immunoprecipitation (Me-RIP) assay. The interaction between RBM15 (RNA binding motif protein 15) and PRNP was probed using RIP assay.

RESULTS

PRNP was highly expressed in DC patients and HG-induced HLECs. Functionally, PRNP deficiency reversed HG-induced apoptosis and oxidative stress in HLECs. Mechanistically, RBM15 induced PRNP m6A modification and directly bound to PRNP. Knockdown of RBM15 abolished HG-induced apoptotic and oxidative injury in HLECs, while these effects were rescued after PRNP overexpression.

CONCLUSION

RBM15 silencing suppressed HG-induced lens epithelial cell injury by regulating PRNP in an m6A-mediated manner, hinting a novel therapeutic strategy for DC patients.

Mitochondrial related variants associated with cardiovascular traits

Introduction

Cardiovascular disease (CVD) is responsible for over 30% of mortality worldwide. CVD arises from the complex influence of molecular, clinical, social, and environmental factors. Despite the growing number of autosomal genetic variants contributing to CVD, the cause of most CVDs is still unclear. Mitochondria are crucial in the pathophysiology, development and progression of CVDs; the impact of mitochondrial DNA (mtDNA) variants and mitochondrial haplogroups in the context of CVD has recently been highlighted.

Aims

We investigated the role of genetic variants in both mtDNA and nuclear-encoded mitochondrial genes (NEMG) in CVD, including coronary artery disease (CAD), hypertension, and serum lipids in the UK Biobank, with sub-group analysis for diabetes.

Methods

We investigated 371,542 variants in 2,527 NEMG, along with 192 variants in 32 mitochondrial genes in 381,994 participants of the UK Biobank, stratifying by presence of diabetes.

Results

Mitochondrial variants showed associations with CVD, hypertension, and serum lipids. Mitochondrial haplogroup J was associated with CAD and serum lipids, whereas mitochondrial haplogroups T and U were associated with CVD. Among NEMG, variants within Nitric Oxide Synthase 3 (NOS3) showed associations with CVD, CAD, hypertension, as well as diastolic and systolic blood pressure. We also identified Translocase Of Outer Mitochondrial Membrane 40 (TOMM40) variants associated with CAD; Solute carrier family 22 member 2 (SLC22A2) variants associated with CAD and CVD; and HLA-DQA1 variants associated with hypertension. Variants within these three genes were also associated with serum lipids.

Conclusion

Our study demonstrates the relevance of mitochondrial related variants in the context of CVD. We have linked mitochondrial haplogroup U to CVD, confirmed association of mitochondrial haplogroups J and T with CVD and proposed new markers of hypertension and serum lipids in the context of diabetes. We have also evidenced connections between the etiological pathways underlying CVDs, blood pressure and serum lipids, placing NOS3, SLC22A2, TOMM40 and HLA-DQA1 genes as common nexuses.

Genetic variants affecting mitochondrial function provide further insights for kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a complex disorder that has become a high prevalence global health problem, with diabetes being its predominant pathophysiologic driver. Autosomal genetic variation only explains some of the predisposition to kidney disease. Variations in the mitochondrial genome (mtDNA) and nuclear-encoded mitochondrial genes (NEMG) are implicated in susceptibility to kidney disease and CKD progression, but they have not been thoroughly explored. Our aim was to investigate the association of variation in both mtDNA and NEMG with CKD (and related traits), with a particular focus on diabetes.

METHODS

We used the UK Biobank (UKB) and UK-ROI, an independent collection of individuals with type 1 diabetes mellitus (T1DM) patients.

RESULTS

Fourteen mitochondrial variants were associated with estimated glomerular filtration rate (eGFR) in UKB. Mitochondrial variants and haplogroups U, H and J were associated with eGFR and serum variables. Mitochondrial haplogroup H was associated with all the serum variables regardless of the presence of diabetes. Mitochondrial haplogroup X was associated with end-stage kidney disease (ESKD) in UKB. We confirmed the influence of several known NEMG on kidney disease and function and found novel associations for SLC39A13, CFL1, ACP2 or ATP5G1 with serum variables and kidney damage, and for SLC4A1, NUP210 and MYH14 with ESKD. The G allele of TBC1D32-rs113987180 was associated with higher risk of ESKD in patients with diabetes (OR:9.879; CI95%:4.440-21.980; P = 2.0E-08). In UK-ROI, AGXT2-rs71615838 and SURF1-rs183853102 were associated with diabetic nephropathies, and TFB1M-rs869120 with eGFR.

CONCLUSIONS

We identified novel variants both in mtDNA and NEMG which may explain some of the missing heritability for CKD and kidney phenotypes. We confirmed the role of MT-ND5 and mitochondrial haplogroup H on renal disease (serum variables), and identified the MT-ND5-rs41535848G variant, along with mitochondrial haplogroup X, associated with higher risk of ESKD. Despite most of the associations were independent of diabetes, we also showed potential roles for NEMG in T1DM.

Genomics in Diabetic Kidney Disease: A 2024 Update

Diabetic Kidney Disease (DKD) remains the leading cause of Chronic and End Stage Kidney Disease (ESKD) worldwide, with an increasing epidemiological burden. However, still, the disease awareness remains low, early diagnosis is difficult, and therapeutic management is ineffective. These might be attributed to the fact that DKD is a highly heterogeneous disease, with disparities and variability in clinical presentation and progression patterns. Besides environmental risk factors, genetic studies have emerged as a novel and promising tool in the field of DKD. Three decades ago, family studies first reported that inherited genetic factors might confer significant risk to DKD development and progression. During the past decade, genome-wide association studies (GWASs) screening the whole genome in large and multi-ethnic population-based cohorts identified genetic risk variants associated with traits defining DKD in both type 1 and 2 diabetes. Herein, we aim to summarize the existing data regarding the progress in the field of genomics in DKD, present how the revolution of GWAS expanded our understanding of pathophysiologic disease mechanisms and finally, suggest potential future directions.

Association between nitric oxide synthase (NOS3) gene polymorphisms and diabetic nephropathy: An updated meta-analysis

Polymorphisms located within NOS3 gene have been investigated as susceptibility variants for diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) in a large number of studies. However, these previous articles yielded inconsistent results and we aimed at elucidating the impact of NOS3 variants on DN risk in T2DM by conducting an updated systematic data synthesis. A total of 36 studies (12,807 participants) were selected for qualitative data synthesis, while 33 records with 11,649 subjects were included in the meta-analysis. The pooled analysis demonstrated the association of minor alleles of rs2070744 and rs1799983 with an increased susceptibility to DN (P < 0.001 and P = 0.015 for allelic model, respectively). For both of these variants, a significant effect of subgrouping according to ethnicity was found. Rs869109213 displayed an association with DN susceptibility, with pooled effect measures indicating a predisposing effect of the minor allele a (Prec = 0.002, ORrec = 1.960, 95%CI 1.288-2.983; Paavs. bb = 0.001, ORaavs. bb = 2.014, 95%CI 1.316-3.083). These findings support the effects of NOS3 variants on the risk of developing DN in T2DM.

Uncovering the key pharmacodynamic material basis and possible molecular mechanism of Xiaoke formulation improve insulin resistant through a comprehensive investigation

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoke formulation (XKF) has been utilized in clinical practice for decades in China as a treatment option for mild to moderate type 2 diabetes. However, there is still a need for systematic research to uncover the key pharmacodynamic material basis and mechanism of XKF.

AIM OF THE STUDY

Aim of to investigate the distribution and metabolism of XKF in normal and insulin resistant (IR) mice were different, and elucidate its key pharmacodynamic material basis and mechanism of action.

MATERIALS AND METHODS

Ultra performance liquid chromatography/time of flight mass spectrometry technology was employed to investigate the differences in XKF absorption, distribution, and metabolism between normal and IR mice across blood, liver, feces, and urine samples. Further, network pharmacology was used to predict target proteins and their associated signaling pathways. Then, molecular docking was utilized to validate the activity of key pharmacodynamic components and targets. Finally, IR HepG2 cells were used to detect the glucose consumption under the action of key pharmacodynamic material basis. In addition, the expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT) and phospho-protein kinase B (p-AKT) was determined using western blotting.

RESULTS

The study demonstrates significant distinctions in plasma and liver number and abundance of alkaloids, organic acids, flavonoids, iridoids and saponins between normal and IR mice when XKF was administered. Further analysis has shown that the representative components of XKF, including berberine, chlorogenic acid, calycosin, swertiamarin and astragaloside IV have significantly different metabolic pathways in plasma and liver. Prototypes and metabolites of these components were rarely detected in the urine and feces of mice. According to the network pharmacological analysis, these differential components are predicted to improve IR by targeting key factors such as SRC, JUN, HRAS, NOS3, FGF2, etc. Additionally, the signaling pathways involved in this process include PI3K-AKT pathway, GnRH signaling pathway, and T cell receptor signaling pathway. In addition, in vitro experiments indicate that berberine and its metabolites (berberine and demethyleneberine), chlorogenic acid and its metabolites (3-O-ferulic quinic acid and 5-O-ferulic quinic acid), calycosin and swertiamarin could improve IR in IR-HepG2 cells by elevating the expression of PI3K and AKT, leading to an increase in glucose consumption.

CONCLUSION

The key pharmacodynamic material basis of XKF, such as berberine and its metabolites (berberrubine and demethyleneberberine), chlorogenic acid and its metabolites (3-O-feruloylquinic acid and 5-O-feruloylquinic acid), calycosin and swertiamarin influence the glucose metabolism disorder of IR-HepG2 cells by regulating the PI3K/AKT signalling pathway, leading to an improvement in IR.

Can pharmaceutical care decrease the oxidative stress in type 2 diabetes mellitus?

Type 2 diabetes mellitus (T2D) is a chronic metabolic disorder characterized by an increase in oxidative stress, which is itself related to development of T2D's main chronic complications. Oxidative stress caused by elevated production of reactive species of oxygen and decrease of antioxidant defense system level, leads to activation of lipid peroxidation (LPO) and oxidative lipoprotein modification with increasing atherogenicity. Therefore, the aim of this study was to evaluate whether pharmacotherapeutic follow-up in patients with T2D, users and non-users of insulin, interferes with the levels of oxidative stress, measuring lipid peroxidation and protein oxidation, nitric oxide and superoxide dismutase levels. After the follow-up, there was a decrease in nitric oxide levels and an increase in superoxide dismutase concentration for the group with insulin therapy. Accordingly, these results show that the proposed pharmaceutical care program reduced the oxidative stress levels, mainly in patients in insulin therapy, as a consequence, can impact in the surging of the main chronic complications in T2D.

Association between serum total bilirubin and diabetic kidney disease in US diabetic patients

Background

Bilirubin has been widely reported to be a protective factor against diabetic kidney disease (DKD) in Asian populations. However, few large-sample analyses have been conducted in American populations. This study aimed to investigate the association between serum total bilirubin (STB) level and DKD in a US diabetic cohort.

Methods

This cross-sectional study enrolled participants from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. Univariate and multivariate logistic regression analyses were performed to assess the association between STB level and DKD. Three models were conducted to control the potential confounding factors. Subgroup analysis was carried out for further validation.

Results

Among the 5,355 participants, the median age [interquartile range (IQR)] was 62 [52-71] years; 2,836 (52.96%) were male, and 1,576 (29.43%) were diagnosed with DKD. In the entire cohort, no significant association between STB level and DKD was observed in any logistic regression models (p > 0.05). Subgroup analysis revealed that, in U.S. diabetic males, STB levels > 11.98 µmol/L were associated with a nearly 30% lower risk of DKD than STB levels ≤ 8.55 µmol/L. Additionally, a moderate STB level (8.56-11.98 μmol/L) was found associated with a nearly 25% lower risk of DKD in U.S. diabetic patients over 65 years old.

Conclusion

The association of STB level with DKD may depict differences across diverse populations, among which the impact of race, sex, and age requires thorough consideration and relevant inferences should be interpreted cautiously.

Oxidatively stressed extracellular microenvironment drives fibroblast activation and kidney fibrosis

Kidney fibrosis is associated with tubular injury, oxidative stress and activation of interstitial fibroblasts. However, whether these events are somehow connected is poorly understood. In this study, we show that glutathione peroxidase-3 (GPX3) depletion in renal tubular epithelium after kidney injury plays a central role in orchestrating an oxidatively stressed extracellular microenvironment, which drives interstitial fibroblast activation and proliferation. Through transcriptional profiling by RNA-sequencing, we found that the expression of GPX3 was down-regulated in various models of chronic kidney disease (CKD), which was correlated with induction of nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase-4 (NOX4). By using decellularized extracellular matrix (ECM) scaffold, we demonstrated that GPX3-depleted extracellular microenvironment spontaneously induced NOX4 expression and reactive oxygen species (ROS) production in renal fibroblasts and triggered their activation and proliferation. Activation of NOX4 by advanced oxidation protein products (AOPPs) mimicked the loss of GPX3, increased the production of ROS, stimulated fibroblast activation and proliferation, and activated protein kinase C-α (PKCα)/mitogen-activated protein kinase (MAPK)/signal transducer and activator of transcription 3 (STAT3) signaling. Silencing NOX4 or inhibition of MAPK with small molecule inhibitors hampered fibroblast activation and proliferation. In mouse model of CKD, knockdown of NOX4 repressed renal fibroblast activation and proliferation and alleviated kidney fibrosis. These results indicate that loss of GPX3 orchestrates an oxidatively stressed extracellular microenvironment, which promotes fibroblast activation and proliferation through a cascade of signal transduction. Our studies underscore the crucial role of extracellular microenvironment in driving fibroblast activation and kidney fibrosis.

A reactive oxygen species-related signature to predict prognosis and aid immunotherapy in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is a malignant disease containing tumor-infiltrating lymphocytes. Reactive oxygen species (ROS) are present in the tumor microenvironment and are strongly associated with cancer development. Nevertheless, the role of ROS-related genes in ccRCC remains unclear.

Methods

We describe the expression patterns of ROS-related genes in ccRCC from The Cancer Genome Atlas and their alterations in genetics and transcription. An ROS-related gene signature was constructed and verified in three datasets and immunohistochemical staining (IHC) analysis. The immune characteristics of the two risk groups divided by the signature were clarified. The sensitivity to immunotherapy and targeted therapy was investigated.

Results

Our signature was constructed on the basis of glutamate-cysteine ligase modifier subunit (GCLM), interaction protein for cytohesin exchange factors 1 (ICEF1), methionine sulfoxide reductase A (MsrA), and strawberry notch homolog 2 (SBNO2) genes. More importantly, protein expression levels of GCLM, MsrA, and SBNO2 were detected by IHC in our own ccRCC samples. The high-risk group of patients with ccRCC suffered lower overall survival rates. As an independent predictor of prognosis, our signature exhibited a strong association with clinicopathological features. An accurate nomogram for improving the clinical applicability of our signature was constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed that the signature was closely related to immune response, immune activation, and immune pathways. The comprehensive results revealed that the high-risk group was associated with high infiltration of regulatory T cells and CD8+ T cells and more benefited from targeted therapy. In addition, immunotherapy had better therapeutic effects in the high-risk group.

Conclusion

Our signature paved the way for assessing prognosis and developing more effective strategies of immunotherapy and targeted therapy in ccRCC.

Redox Systems Biology in Chronic Kidney Disease

Collapse

Glutathione Peroxidase 4 Is a Predictor of Diabetic Kidney Disease Progression in Type 2 Diabetes Mellitus

BACKGROUND

Diabetic kidney disease (DKD) represents a heavy burden in type 2 diabetes mellitus (T2DM). Ferroptosis plays an important role in DKD, and it thus provides new perspectives to pursue more related biomarkers to assess the disease severity and prognosis. Glutathione peroxidase 4 (GPX4) is the mainstay in regulating ferroptosis. The current study investigated the predictive value of kidney GPX4 expression level in DKD progression.

METHODS

We measured GPX4 levels in kidney paraffin sections of 85 biopsy-proven DKD patients by immunohistochemistry staining. The associations between the GPX4 level and clinicopathological parameters as well as renal outcomes were analyzed.

RESULTS

GPX4 is mainly expressed in kidney tubulointerstitium, especially in tubular epithelial cells of DKD patients. The GPX4 expression level was significantly lower in DKD patients than healthy controls. Besides, GPX4 level significantly correlated with proteinuria (r = -0.42, p < 0.001), urinary albumin-to-creatinine ratio (uACR) (r = -0.40, p < 0.01), serum creatinine (Scr) (r = -0.59, p < 0.001), estimated glomerular filtration rate (eGFR) (r = 0.66, p < 0.001), and the percentage of sclerosed glomeruli (r = -0.42, p < 0.001) in renal specimens. During follow-up, the GPX4 level positively correlated with eGFR slope (r = 0.48, p < 0.001), and GPX4-low patients showed a significantly higher probability of developing end-stage kidney disease (ESKD) compared with GPX4-high patients (p < 0.01). Moreover, after adjusting for other potential predictors, the GPX4 level was still an independent predictor of developing ESKD (HR 2.15, 95% CI 1.08 to 4.28, p < 0.05).

CONCLUSIONS

Kidney tubulointerstitial GPX4 expression level was associated with the disease severity and progression of DKD.

Selenium and Selenoproteins at the Intersection of Type 2 Diabetes and Thyroid Pathophysiology

Type 2 diabetes (T2D) is considered one of the largest global public-health concerns, affecting approximately more than 400 million individuals worldwide. The pathogenesis of T2D is very complex and, among the modifiable risk factors, selenium (Se) has recently emerged as a determinant of T2D pathogenesis and progression. Selenium is considered an essential element with antioxidant properties, and is incorporated into the selenoproteins involved in the antioxidant response. Furthermore, deiodinases, the enzymes responsible for homeostasis and for controlling the activity of thyroid hormones (THs), contain Se. Given the crucial action of oxidative stress in the onset of insulin resistance (IR) and T2D, and the close connection between THs and glucose metabolism, Se may be involved in these fundamental relationships; it may cover a dual role, both as a protective factor and as a risk factor of T2D, depending on its basal plasma concentration and the individual’s diet intake. In this review we discuss the current evidence (from experimental, observational and randomized clinical studies) on how Se is associated with the occurrence of T2D and its influence on the relationship between thyroid pathophysiology, IR and T2D.