Therapeutic potential of Nrf2 activators in streptozotocin-induced diabetic nephropathy

Nuclear Factor Erythroid 2-Related Factor 2 Activator DDO-1039 Ameliorates Podocyte Injury in Diabetic Kidney Disease via Suppressing Oxidative Stress, Inflammation, and Ferroptosis

Aims: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and podocyte injury is one of the major contributors to DKD. As a crucial transcriptional factor that regulates cellular response to oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) is an attractive therapeutic target for DKD. In this study, we evaluated the therapeutic potential of DDO-1039, a novel small-molecule Nrf2 activator developed with protein-protein interaction strategy, on podocyte injury in DKD. Results: DDO-1039 treatment significantly increased Nrf2 protein level and Nrf2 nuclear translocation, thereby upregulating Nrf2 target genes [heme oxygenase 1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase modifier, and tyrosine-protein kinase receptor] both in vitro and in vivo. DDO-1039 attenuated glomerular sclerosis and podocyte injury in the high-fat diet/streptozotocin-induced (HFD/STZ) diabetic mice and db/db diabetic mice. It also significantly improved hyperglycemia in both diabetic mice and mitigated proteinuria in HFD/STZ mice. Meanwhile, DDO-1039 attenuated oxidative stress and inflammation as well as apoptosis in vivo and in podocytes stimulated with palmitic acid and high glucose. Interestingly, we identified podocyte protective factor Tyro3 as a novel Nrf2-regulated gene. In addition, podocyte ferroptosis is reduced via activation of glutathione peroxidase 4 by the novel Nrf2 activator. Innovation and conclusion: DDO-1039 activates the Nrf2-based cytoprotective system to mitigate podocyte injury in the context of diabetes, suggesting the potential of DDO-1039 in the treatment of DKD. Antioxid. Redox Signal. 42, 787-806.

Emerging Biomarkers and Innovative Therapeutic Strategies in Diabetic Kidney Disease: A Pathway to Precision Medicine

Diabetes mellitus (DM) has emerged as the most common cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) globally in recent years. Diabetic nephropathy (DN), or diabetic kidney disease (DKD) that occurs as a direct consequence of DM, has complex pathophysiological mechanisms, such as various inflammatory processes and genetic and epigenetic factors, often accentuated by comorbid illnesses like hypertension and dyslipidemia. Therefore, management of DKD involves targeting these etio-pathological processes. Various medications with remarkable disease modifying properties have been introduced for treatment of DN in recent years. We update the current and future diagnostic and therapeutic landscapes against DKD in this article.

Long-term blood glucose control via glucose-activated transcriptional regulation of insulin analogue in type 1 diabetes mice

AIM

To achieve glucose-activated transcriptional regulation of insulin analogue in skeletal muscle of T1D mice, thereby controlling blood glucose levels and preventing or mitigating diabetes-related complications.

MATERIALS AND METHODS

We developed the GANIT (Glucose-Activated NFAT-regulated INSA-F Transcription) system, an innovative platform building upon the previously established intramuscular plasmid DNA (pDNA) delivery and expression system. In the GANIT system, skeletal muscle cells are genetically engineered to endogenously produce the insulin analogue INSA-F (Insulin Aspart with Furin cleavage sites). The transcription of INSA-F is precisely controlled by a glucose-responsive promoter containing NFAT (Nuclear Factor of Activated T-cells) regulatory motifs, which can be activated in response to changes in extracellular glucose concentrations. This design enables glucose-dependent regulation of insulin analogue expression, mimicking physiological glucose-responsive insulin secretion.

RESULTS

T1D mice that received two GANIT treatments over a 2-month experimental period demonstrated significant improvements in glucose homeostasis, glucose tolerance and glycated haemoglobin (HbA1c) levels. Additionally, the treatment effectively reduced oxidative stress and alleviated cardiac and renal fibrosis, while maintaining a favourable biosafety profile.

CONCLUSION

The GANIT system provides significant advantages in terms of efficiency, convenience and cost-effectiveness, making it a promising approach for regulating blood glucose levels and alleviating diabetes-related complications in insulin-deficient diabetes.

Health position paper and redox perspectives - Bench to bedside transition for pharmacological regulation of NRF2 in noncommunicable diseases

Nuclear factor erythroid 2-related factor 2 (NRF2) is a redox-activated transcription factor regulating cellular defense against oxidative stress, thereby playing a pivotal role in maintaining cellular homeostasis. Its dysregulation is implicated in the progression of a wide array of human diseases, making NRF2 a compelling target for therapeutic interventions. However, challenges persist in drug discovery and safe targeting of NRF2, as unresolved questions remain especially regarding its context-specific role in diseases and off-target effects. This comprehensive review discusses the dualistic role of NRF2 in disease pathophysiology, covering its protective and/or destructive roles in autoimmune, respiratory, cardiovascular, and metabolic diseases, as well as diseases of the digestive system and cancer. Additionally, we also review the development of drugs that either activate or inhibit NRF2, discuss main barriers in translating NRF2-based therapies from bench to bedside, and consider the ways to monitor NRF2 activation in vivo.

Thirty years of NRF2: advances and therapeutic challenges

Over the last 30 years, NRF2 has evolved from being recognized as a transcription factor primarily involved in redox balance and detoxification to a well-appreciated master regulator of cellular proteostasis, metabolism and iron homeostasis. NRF2 plays a pivotal role in diverse pathologies, including cancer, and metabolic, inflammatory and neurodegenerative disorders. It exhibits a Janus-faced duality, safeguarding cellular integrity in normal cells against environmental insults to prevent disease onset, whereas in certain cancers, constitutively elevated NRF2 levels provide a tumour survival advantage, promoting progression, therapy resistance and metastasis. Advances in understanding the mechanistic regulation of NRF2 and its roles in human pathology have propelled the investigation of NRF2-targeted therapeutic strategies. This Review dissects the mechanistic intricacies of NRF2 signalling, its cross-talk with biological processes and its far-reaching implications for health and disease, highlighting key discoveries that have shaped innovative therapeutic approaches targeting NRF2.

Activation of the Nrf2 Pathway by Sulforaphane Improves Hypoglycaemia-Induced Cognitive Impairment in a Rodent Model of Type 1 Diabetes

In diabetes, chronic hyperglycaemia leads to cognitive impairment, neurodegeneration and dementia. In a rodent model of streptozotocin (STZ)-induced type 1 diabetes (STZ-T1D), we previously demonstrated that recurrent hypoglycaemia (RH) further exacerbates this process through a mechanism involving increased oxidative and inflammatory stress that overwhelms the compensatory activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant system, which was insufficient to prevent cognitive impairment. The current study investigated whether the induction of the antioxidant response through pre-treatment with sulforaphane (SFN), a potent Nrf2 inducer, would ameliorate these cognitive deficits. A mouse model of chronic insulin-treated T1D was achieved using STZ (125 mg/kg i.p.) and insulin implants (Linbit®). Diabetic and Control (C57BL6/J) mice were randomly allocated to one of the following seven groups: (i) Control, (ii) STZ-T1D, (iii) Control + RH, (iv) STZ-T1D + RH, (v) Control + RH + SFN, (vi) STZ-T1D + RH + SFN or (vii) STZ-T1D + SFN, and subjected to insulin-induced hypoglycaemia (three episodes per week for four weeks). SFN (50 mg/kg i.p.) or a vehicle (0.1% DMSO/PBS i.p.) were administered 24 h before each hypoglycaemic episode. Cognition was assessed with the Novel Object Recognition (NOR) and spontaneous alternation (SA) tasks. SFN significantly improved the cognitive performance in the 24-h NOR and SA tasks in the STZ-T1D + RH groups. These improvements were absent in the Control or Nrf2-null mice receiving SFN. These studies show, for the first time, that the pharmacological activation of the Nrf2 antioxidant pathway may provide a novel therapeutic target for treating cognitive impairment associated with RH in T1D.

Diphenyl diselenide protects against diabetic kidney disease through modulating gut microbiota dysbiosis in streptozotocin-induced diabetic rats

Introduction

Diphenyl diselenide (DPDS) ameliorates nephropathy in streptozotocin (STZ)-induced type 1 diabetic rats by inhibiting oxidative stress and inflammatory reactions. However, it has not been clarified whether DPDS alleviates type 1 diabetic kidney disease (DKD) is related to the inhibition of extracellular matrix (ECM) production and the regulation of intestinal flora disorder.

Methods

The present study investigated the effects of DPDS on ECM generation in the kidney and intestinal microflora composition in feces. The rats were orally administered DPDS or metformin for eight weeks. Various indices were measured to assess the severity of renal injury. After euthanizing the rats, oxidative stress markers in serum and kidney were assessed using biochemical methods, and the expressions of ECM-related proteins in kidney were analyzed using Western blot. Additionally, 16S rRNA high-throughput sequencing was used to evaluate the diversity and composition of the intestinal flora in feces.

Results

The results showed DPDS and metformin improved the DKD in STZ rats, as evidenced by decreased blood glucose, BUN, urine volume, urine microalbumin, urinary β2 microglobulin, and improvement of renal pathological morphology. Furthermore, DPDS intervention markedly reduced the protein expression of α-SMA, COI Ⅳ, FN, and vimentin in the kidneys. Besides, DPDS not only improved dyslipidemia in STZ diabetic rats, but also enhanced the activities of antioxidant enzymes, decreased the level of MDA in serum and kidney, and regulated the expression of proteins related to the Nrf2/Keap1 signaling pathway in the kidney. Moreover, we found that DPDS could selectively improve the relative abundance of probiotics as well as the diversity of flora, thus ameliorating the intestinal microbial composition of the STZ rats, significantly regulating the intestinal microbial homeostasis.

Discussion

Overall, DPDS inhibited ECM production and improved renal pathological changes, which may be related to reducing oxidative stress damage in the kidney and improving intestinal flora imbalance, providing data support for the further development and application of DPDS in DKD.

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.

Sulforaphane regulates AngII-induced podocyte oxidative stress injury through the Nrf2-Keap1/ho-1/ROS pathway

OBJECTIVE

This study aimed to investigate the therapeutic effects of sulforaphane and the role of the Nrf2-Keap1/HO-1/ROS pathway in AngII-induced oxidative stress in podocyte injury.

METHODS

Mouse mpc5 podocytes were divided into four groups: control (Con), AngII, AngII + sulforaphane (AngII + SFN), and control + sulforaphane (Con + SFN). Western blotting was used to detect protein expression of Nrf2-Keap1, antioxidant enzyme HO-1, and apoptosis-related proteins. ROS levels were measured using a ROS assay kit, and cell survival and viability were assayed using the CCK-8 kit. Molecular interactions between Nrf2 and sulforaphane were analyzed computationally.

RESULTS

Compared with the Con group, podocytes treated with AngII alone exhibited inhibited proliferation, reduced cell viability, lower Bcl-2 expression, and higher cleaved caspase 3 expression. In the presence of sulforaphane, AngII group showed a mild inhibition on podocyte proliferation but did not induce the aforementioned changes in Bcl-2 and cleaved caspase 3 expression. Similarly, compared to the Con group, AngII treatment alone had lower Nrf2 expression and higher Keap1 expression in podocytes, accompanied by a significant decrease in ROS content. However, in the presence of sulforaphane, AngII failed to induce increases in Nrf2 and a decrease in Keap1 expression, as well as ROS levels. Furthermore, cells treated with sulforaphane exhibited higher HO-1 levels than control cells, and co-incubation with AngII did not alter HO-1 levels. Computational modeling revealed hydrophobic interactions between sulforaphane and the amino acid LYS-462 of Nrf2, as well as hydrogen bonding with amino acid HIS-465. The binding score between sulforaphane and Nrf2 was -4.7.

CONCLUSION

Sulforaphane alleviated AngII-induced podocyte oxidative stress injury via the Nrf2-Keap1/HO-1/ROS pathway, providing new insights into therapeutic compounds for mitigating chronic kidney disease.

Naturally-derived modulators of the Nrf2 pathway and their roles in the intervention of diseases

Cumulative evidence has verified that persistent oxidative stress is involved in the development of various chronic diseases, including pulmonary, neurodegenerative, kidney, cardiovascular, and liver diseases, as well as cancers. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in regulating cellular oxidative stress and inflammatory reactions, making it a focal point for disease prevention and treatment strategies. Natural products are essential resources for discovering leading molecules for new drug research and development. In this review, we comprehensively outlined the progression of the knowledge on the Nrf2 pathway, Nrf2 activators in clinical trials, the naturally-derived Nrf2 modulators (particularly from 2014-present), as well as their effects on the pathogenesis of chronic diseases.

Renal microRNA-144-3p is associated with transforming growth factor-β1-induced oxidative stress and fibrosis by suppressing the NRF2 pathway in hypertensive diabetic kidney disease

Chronic kidney disease (CKD) is a global health problem characterized by progressive renal fibrosis and excessive extracellular matrix deposition. Oxidative stress and epigenetic regulation, particularly through microRNAs (miRNAs), play crucial roles in the pathogenesis of CKD. In this study, we investigated the role of urinary miR-144-3p, which is upregulated in rats with CKD induced by diabetes and hypertension, in renal fibrosis progression, particularly its regulation of the nuclear factor erythroid-2-related factor 2 (NRF2) pathway. Our findings revealed elevated miR-144-3p levels and reduced NRF2 and target gene levels in kidney tissues of streptozotocin-treated spontaneously hypertensive rats. In vitro experiments demonstrated that miR-144-3p directly binds to the 3'-untranslated region of nrf2, suppressing the NRF2 pathway in renal tubular epithelial cells. Additionally, the profibrogenic factor transforming growth factor (TGF)-β1 increased miR-144-3p expression. TGF-β1-induced NRF2 suppression and reactive oxygen species elevation were found to be mediated through miR-144-3p upregulation. In vivo, cilostazol, an antiplatelet drug with an NRF2-activating effect, ameliorated renal injury in diabetic hypertensive rats by decreasing TGF-β1 and miR-144-3p levels while increasing NRF2 and its target gene levels in the kidneys. These findings highlight the potential therapeutic value of targeting the miR-144-3p/NRF2 pathway to attenuate CKD progression in hypertensive diabetic conditions.

Amelioration of full-thickness cutaneous wound healing using stem cell exosome and zinc oxide nanoparticles in rats

Background

Wound healing is a complex procedure that requires the coordination of several factors, so this study aimed to assess the zinc oxide nanoparticles' regenerated effect and stem cell exosomes on full-thickness wounds in rats.

Methods

Seventy-two Wistar male rats were subjected to a full-thickness skin defect (20 mm2) on the dorsal surface of each rat between two shoulder joints. The rats were randomized into four groups (18/group) according to wound treatments. The wounds were irrigated with normal saline (Control group), or the wound's edges were subcutaneously injected daily with 0.3 ml of exosome (Exo-group), or 1 ml of zinc oxide nanoparticles (ZnO2-NPs group), or 0.3 ml of exosome in combined with 1 ml of zinc oxide nanoparticles (Exo/ZnO2-NPs group). On the 7th, 14th, and 21st days post-wounding, the weight of the rats, the wound healing breaking strength, the wound size, and the contraction percent were evaluated. Six rats in each group were euthanized at each time point for histopathological, immunohistochemical examination of collagen, the levels of alpha-smooth muscle actin (α-SMA), and epidermal growth factor receptor (EGFR). additionally, the gene expression analysis of the relative renal nuclear factor erythroid 2-related factor2 (Nrf2 mRNA), Transforming growth factor beta-1 (TGFβ1), fibroblast growth factor-7 (FGF7), Transforming growth factor beta-1 (TGFβ1), Lysyl oxidase (LOX), and Vascular endothelial growth factor (VEGF) were applied.

Results

The Exo-group exhibited a significant decrease in wound size and a significant increase in wound contraction compared with other groups. Histopathologically evaluation during the three intervals revealed that the Exo-group had the highest collagen deposition area with a significant reduction of the granulation tissue. Moreover, upregulated gene expression profiles of the growth factors genes at all time points post-wounding.

Discussion

The exosomes-treated group revealed superior wound healing and contraction, with minimal inflammatory signs, higher angiogenesis, and myofibroblasts, and associated with higher growth factor expression genes compared to the other groups.

Conclusions

Exosome-based therapy demonstrates potential as a treatment method to promote and accelerate wound healing by modulating angiogenesis, re-epithelialization, collagen deposition, and gene expression profiles.

Gallic Acid Alleviates Glucolipotoxicity-Induced Nephropathy by miR-709-NFE2L2 Pathway in db/db Mice on a High-Fat Diet

BACKGROUND

Type 2 diabetes mellitus (T2DM) has become a major global issue, with diabetic nephropathy (DN) ranking as one of its most serious complications. The involvement of microRNAs (miRNAs) in the progression of T2DM and DN is an area of active research, yet the molecular mechanisms remain only partially elucidated. Gallic acid (GA), a naturally occurring polyphenolic compound found in various plants such as bearberry leaves, pomegranate root bark, tea leaves, and oak bark, has demonstrated antioxidant properties that may offer therapeutic benefits in DN.

METHODS AND RESULTS

The study aimed to investigate the therapeutic potential of GA in mitigating kidney fibrosis, oxidative stress and inflammation, within a glucolipotoxicity-induced diabetic model using db/db mice. The mice were subjected to a high-fat diet to induce glucolipotoxicity, a condition that mimics the metabolic stress experienced in T2DM. Through microarray data analysis, we identified a significant upregulation of renal miR-709a-5p in the diabetic mice, linking this miRNA to the pathological processes underlying DN. GA treatment was shown to boost the activity of including catalase, essential antioxidant enzymes, glutathione peroxidase and superoxide dismutase, while also reducing lipid accumulation in the kidneys, indicating a protective effect against HFD-induced steatosis. In vitro experiments further revealed that silencing miR-709a-5p in MES-13 renal cells led to a reduction in oxidative stress markers, notably lowering lipid peroxidation markers, and significantly boosting the activity of antioxidant defenses. Additionally, NFE2L2, a crucial transcription factor involved in the antioxidant response, was identified as a direct target of miR-709a-5p. The downregulation of miR-709a-5p by GA suggests that this polyphenol mitigates glucolipotoxicity-induced lipogenesis and oxidative stress, potentially offering a novel therapeutic avenue for managing diabetic fatty liver disease and DN.

CONCLUSION

Our findings indicate that GA exerts a protective effect in DN by downregulating miR-709a-5p, thereby alleviating oxidative stress through the suppression of NFE2L2. The results highlight the potential of GA and NFE2L2-activating agents as promising therapeutic strategies in the treatment of DN.

Molecular Therapeutics for Diabetic Kidney Disease: An Update

Diabetic kidney disease (DKD) is a common microvascular complication of diabetes mellitus (DM). With the increasing prevalence of DM worldwide, the incidence of DKD remains high. If DKD is not well controlled, it can develop into chronic kidney disease or end-stage renal disease (ESRD), which places considerable economic pressure on society. Traditional therapies, including glycemic control, blood pressure control, blood lipid control, the use of renin-angiotensin system blockers and novel drugs, such as sodium-glucose cotransporter 2 inhibitors, mineralocorticoid receptor inhibitors and glucagon-like peptide-1 receptor agonists, have been used in DKD patients. Although the above treatment strategies can delay the progression of DKD, most DKD patients still ultimately progress to ESRD. Therefore, new and multimodal treatment methods need to be explored. In recent years, researchers have continuously developed new treatment methods and targets to delay the progression of DKD, including miRNA therapy, stem cell therapy, gene therapy, gut microbiota-targeted therapy and lifestyle intervention. These new molecular therapy methods constitute opportunities to better understand and treat DKD. In this review, we summarize the progress of molecular therapeutics for DKD, leading to new treatment strategies.

Diagnostic role of SPP1 and collagen IV in a rat model of type 2 diabetes mellitus with MASLD

Type 2 diabetes mellitus combined with metabolic dysfunction-associated steatotic liver disease (MASLD) leads to an increasing incidence of liver injury year by year, and patients are at a significantly higher risk of developing cirrhosis or even liver failure. No drugs have emerged to specifically treat this disease. The aim of this study is to investigate the mechanisms and causative hub genes of type 2 diabetes combined with MASLD. The data were obtained through the GEO platform for bioinformatics analysis and validated by in vitro experiments to find the causative targets of type 2 diabetes mellitus combined with MASLD, which will provide some theoretical basis for the development of future therapeutic drugs. GSE23343 and GSE49541 were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) in type 2 diabetes mellitus combined with MASLD for functional enrichment analysis. And STRING database and Cytoscape software were used to construct Protein-Protein Interaction (PPI) and hub gene networks. And GO (gene ontology, GO) analysis and KEGG (Kyoto encyclopedia of genes and genomes, KEGG) enrichment analysis were performed on target genes. A total of 185 co-expressed DEGs were obtained by differential analysis, and 20 key genes involved in the development and progression of type 2 diabetes were finally screened. These 20 key genes were involved in 529 GO enrichment results and 20 KEGG enrichment results, and were mainly associated with ECM-receptor interaction, Focal adhesion, Human papillomavirus infection, PI3K-Akt signaling pathway, and the Toll-like receptor signaling pathway. A total of two target genes (SPP1, collagen IV) were found to be highly correlated with type 2 diabetes mellitus combined with MASLD. Real time PCR results showed that there was a significant difference in SPP1 and collagen IV mRNA expression among the three groups (P < 0.05). SPP1 and Collagen IV may be candidate biomarkers for type 2 diabetes mellitus combined with MASLD, as verified by bioinformatics screening and in vitro experiments. Our findings provide new targets for the treatment of type 2 diabetes combined with MASLD.

Unveiling the Nutritional Veil of Sulforaphane: With a Major Focus on Glucose Homeostasis Modulation

Abnormal glucose homeostasis is associated with metabolic syndromes including cardiovascular diseases, hypertension, type 2 diabetes mellitus, and obesity, highlighting the significance of maintaining a balanced glucose level for optimal biological function. This highlights the importance of maintaining normal glucose levels for proper biological functioning. Sulforaphane (SFN), the primary bioactive compound in broccoli from the Cruciferae or Brassicaceae family, has been shown to enhance glucose homeostasis effectively while exhibiting low cytotoxicity. This paper assesses the impact of SFN on glucose homeostasis in vitro, in vivo, and human trials, as well as the molecular mechanisms that drive its regulatory effects. New strategies have been proposed to enhance the bioavailability and targeted delivery of SFN in order to overcome inherent instability. The manuscript also covers the safety evaluations of SFN that have been documented for its production and utilization. Hence, a deeper understanding of the favorable influence and mechanism of SFN on glucose homeostasis, coupled with the fact that SFN is abundant in the human daily diet, may ultimately offer theoretical evidence to support its potential use in the food and pharmaceutical industries.

Plasma Asprosin Concentrations are Associated with Progression of Diabetic Kidney Disease

Purpose

To explore the expression of asprosin in subjects with pre-DKD and DKD and to analyze its relationship with kidney injury, inflammation, and glucose and lipid metabolism.

Methods

Based on urine albumin:creatinine ratio (UACr), participants were divided into DM, pre-DKD, and DKD groups. Relevant human physiological and biochemical parameters were detected in the three groups.

Results

We found relatively higher levels of asprosin in both pre-DKD and DKD groups than the DM group. Moreover, data from the Nephroseq database support increased gene expression of asprosin in kidney tissue from DKD patients. Further correlation analysis revealed that the plasma asprosin level was positively correlated with age, waist circumference, waist:hip ratio, systolic blood pressure, creatinine, UACr, triglycerides, HDL-c, fasting insulin, HOMA-IR, and the inflammatory marker G3P and negatively associated with eGFR. Multiple logistical regression analysis showed that asprosin concentration was significantly associated with pre-DKD and DKD after adjusting for sex, age, BMI, WHR, and HOMA-IR, while this correlation was lost after controlling for G3P.

Conclusion

Plasma asprosin is associated with kidney injury in diabetic conditions, and this association might be connected through inflammatory response. Further studies are needed to assess the role and mechanism of asprosin in DKD.

Osthole ameliorates early diabetic kidney damage by suppressing oxidative stress, inflammation and inhibiting TGF-β1/Smads signaling pathway

BACKGROUND

Osthole is a natural active ingredient extracted from the traditional Chinese medicine Cnidium monnieri. It has been demonstrated to have anti-inflammatory, anti-fibrotic, and anti-hyperglycemic properties. However, its effect on diabetic kidney disease (DKD) remains uncertain. This study aims to assess the preventive and therapeutic effects of osthole on DKD and investigate its underlying mechanisms.

METHODS

A streptozotocin/high-fat and high-sucrose diet induced Type 2 diabetic rat model was established. Metformin served as the positive drug control. Diabetic rats were treated with metformin or three different doses of osthole for 8 weeks. Throughout the treatment period, the progression of DKD was assessed by monitoring increases in urinary protein, serum creatinine, urea nitrogen, and uric acid, along with scrutinizing kidney pathology. Enzyme-linked immunosorbent assay (ELISA) was employed to detect inflammatory factors and oxidative stress levels. At the same time, immunohistochemical staining was utilized to evaluate changes in alpha-smooth muscle actin, fibronectin, E-cadherin, and apoptosis. The alterations in TGF-β1/Smads signaling pathway were ascertained through western blot and immunofluorescence. Furthermore, we constructed a high glucose-stimulated HBZY-1 cells model to uncover its molecular protective mechanism.

RESULTS

Osthole significantly reduced fasting blood glucose, insulin resistance, serum creatinine, uric acid, blood urea nitrogen, urinary protein excretion, and glomerular mesangial matrix deposition in diabetic rats. Additionally, significant improvements were observed in inflammation, oxidative stress, apoptosis, and fibrosis levels. The increase of ROS, apoptosis and hypertrophy in HBZY-1 cells induced by high glucose was reduced by osthole. Immunofluorescence and western blot results demonstrated that osthole down-regulated the TGF-β1/Smads signaling pathway and related protein expression.

CONCLUSION

Our findings indicate that osthole exhibits potential preventive and therapeutic effects on DKD. It deserves further investigation as a promising drug for preventing and treating DKD.

Therapeutic Potential of Palmitoylethanolamide in Gastrointestinal Disorders

Palmitoylethanolamide (PEA) is an endocannabinoid-like bioactive lipid mediator belonging to the family of N-acylethanolamines, most abundantly found in peanuts and egg yolk. When the gastrointestinal (GI) effects of PEA are discussed, it must be pointed out that it affects intestinal motility but also modulates gut microbiota. This is due to anti-inflammatory, antioxidant, analgesic, antimicrobial, and immunomodulatory features. Additionally, PEA has shown beneficial effects in several GI diseases, particularly irritable bowel syndrome and inflammatory bowel diseases, as various studies have shown, and it is important to emphasize its relative lack of toxicity, even at high dosages. Unfortunately, there is not enough endogenous PEA to treat disturbed gut homeostasis, even though it is produced in the GI tract in response to inflammatory stimuli, so exogenous intake is mandatory to achieve homeostasis. Intake of PEA could be through animal and/or vegetable food, but bearing in mind that a high dosage is needed to achieve a therapeutic effect, it must be compensated through dietary supplements. There are still open questions pending to be answered, so further studies investigating PEA's effects and mechanisms of action, especially in humans, are crucial to implementing PEA in everyday clinical practice.

MiR-144-5p and miR-21-5p do not drive bone disease in a mouse model of type 1 diabetes mellitus

The increased risk of fractures in patients with type 1 diabetes mellitus (T1DM) is nowadays well recognized. However, the exact mechanism of action of diabetic bone disease has not been fully elucidated. MicroRNAs (miRNAs) are gene regulators that operate post-transcriptionally and have been implicated in the development of various metabolic disorders including T1DM. Previous studies have implicated a role for miR-144-5p and miR-21-5p, which are involved in controlling oxidative stress by targeting Nrf2, in T1DM. To date, it is unclear whether miR-144-5p and miR-21-5p affect bone health in T1DM. Thus, this study aimed to investigate the influence of miR-144-5p and miR-21-5p knockdown in the development of bone disease in T1DM male mice. Therefore, T1DM was induced in 10-wk-old male mice using streptozotocin (STZ). One week later, after development of hyperglycemia, antagomir-144-5p and antagomir-21-5p or their non-targeting control were administered at 10 mg/kg BW once a week until the end of the experiment. At 14 wk of age, glucose levels, bone, and fat mass were analyzed. The results revealed that treating T1DM male mice with antagomir-144-5p and antagomir-21-5p did not protect against diabetes development or bone loss, despite the successful downregulation of the miRNAs and the normalization of Nrf2 mRNA levels in bone tissue. Histological and serological parameters of bone formation or resorption were not altered by the antagomir treatment. Finally, we measured the expression of miRNA-144-5p or miRNA-21-5p in the serum of 30 individuals with T1DM and compared them to non-diabetic controls, but did not find an altered expression of either miRNA. In conclusion, the knockdown of miR-144-5p and miR-21-5p does not affect STZ-induced diabetes development or loss of bone mass in male mice. However, it does normalize expression of the anti-oxidant factor Nrf2 in diabetic bone tissue.

Oxidative Stress: A Culprit in the Progression of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the principal culprit behind chronic kidney disease (CKD), ultimately developing end-stage renal disease (ESRD) and necessitating costly dialysis or kidney transplantation. The limited therapeutic efficiency among individuals with DKD is a result of our finite understanding of its pathogenesis. DKD is the result of complex interactions between various factors. Oxidative stress is a fundamental factor that can establish a link between hyperglycemia and the vascular complications frequently encountered in diabetes, particularly DKD. It is crucial to recognize the essential and integral role of oxidative stress in the development of diabetic vascular complications, particularly DKD. Hyperglycemia is the primary culprit that can trigger an upsurge in the production of reactive oxygen species (ROS), ultimately sparking oxidative stress. The main endogenous sources of ROS include mitochondrial ROS production, NADPH oxidases (Nox), uncoupled endothelial nitric oxide synthase (eNOS), xanthine oxidase (XO), cytochrome P450 (CYP450), and lipoxygenase. Under persistent high glucose levels, immune cells, the complement system, advanced glycation end products (AGEs), protein kinase C (PKC), polyol pathway, and the hexosamine pathway are activated. Consequently, the oxidant-antioxidant balance within the body is disrupted, which triggers a series of reactions in various downstream pathways, including phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), transforming growth factor beta/p38-mitogen-activated protein kinase (TGF-β/p38-MAPK), nuclear factor kappa B (NF-κB), adenosine monophosphate-activated protein kinase (AMPK), and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling. The disease might persist even if strict glucose control is achieved, which can be attributed to epigenetic modifications. The treatment of DKD remains an unresolved issue. Therefore, reducing ROS is an intriguing therapeutic target. The clinical trials have shown that bardoxolone methyl, a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, blood glucose-lowering drugs, such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can effectively slow down the progression of DKD by reducing oxidative stress. Other antioxidants, including vitamins, lipoic acid, Nox inhibitors, epigenetic regulators, and complement inhibitors, present a promising therapeutic option for the treatment of DKD. In this review, we conduct a thorough assessment of both preclinical studies and current findings from clinical studies that focus on targeted interventions aimed at manipulating these pathways. We aim to provide a comprehensive overview of the current state of research in this area and identify key areas for future exploration.

Role of kidney function on Nrf2 mRNA levels in type 2 diabetes

INTRODUCTION

Diabetic kidney disease (DKD) is a major complication in patients with diabetes and the main contributor to the chronic kidney disease (CKD) global burden. Oxidative stress is a crucial factor in DKD pathogenesis but the role of the antioxidant nuclear factor erythroid 2-related factor 2 (Nrf2) and its molecular regulators has been poorly investigated in man.

RESEARCH DESIGN AND METHODS

In this case-control study, we analyzed the roles of Nrf2, a transcription factor shielding cells from oxidative stress, its repressor Kelch-like ECH-associated protein 1 (Keap1) and six microRNAs (miRNAs) that potentially suppress Nrf2. We categorized 99 participants into 3 groups: 33 non-dialysis patients with type 2 diabetes with DKD, 33 patients with type 2 diabetes without DKD and 33 control subjects and quantified the gene expression (messenger RNA (mRNA)) levels of Nrf2, Keap1 and 6 miRNAs. Moreover, we studied the correlation between gene expression levels and clinical indicators of kidney health.

RESULTS

In patients with diabetes with DKD, Nrf2 mRNA levels were significantly lower than in patients without DKD (p=0.01) and controls (p=0.02), whereas no difference in Nrf2 expression levels existed between patients without DKD and controls. Conversely, in patients with and without DKD, Keap1 expression levels were significantly higher than in controls. Of the six miRNAs studied, miRNA 30e-5p showed differential expression, being markedly reduced in patients with DKD (p=0.007). Nrf2 mRNA levels directly correlated with estimated glomerular filtration rate (eGFR) in patients with DKD (r=0.34, p=0.05) and in a formal mediation analysis the eGFR emerged as the first factor in rank for explaining the difference in Nrf2 mRNA levels between patients with and without DKD.

CONCLUSIONS

The observed dysregulation in the Nrf2-Keap1 axis and the unique expression pattern of miRNA30e-5p in DKD underscore the need for more focused research in this domain that can help identify novel intervention strategies for DKD in patients with type 2 diabetes.

Formononetin, a bioactive isoflavonoid constituent from Astragalus membranaceus (Fisch.) Bunge, ameliorates type 1 diabetes mellitus via activation of Keap1/Nrf2 signaling pathway: An integrated study supported by network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Type 1 diabetes mellitus (T1DM) results from insulin deficiency due to the destruction of pancreatic β-cells. Previously, our studies showed that inhibition of Keap1/Nrf2 signaling pathway promoted the onset of T1DM, which suggests that finding drugs that can activate the Keap1/Nrf2 signaling may be a promising therapeutic strategy for the T1DM treatment. Astragalus membranaceus (Fisch.) Bunge is a common traditional Chinese medicine that has been frequently applied in Chinese clinics for the treatment of diabetes and other diseases. Formononetin (FMNT), one of the major isoflavonoid constituents isolated from this herbal medicine, possesses diverse pharmacological benefits and T1DM therapeutic potential. However, the exact molecular mechanisms underlying the action of FMNT in ameliorating T1DM have yet to be fully elucidated.

AIMS OF THE STUDY

This study is to investigate the regulation of FMNT on the Keap1/Nrf2 signaling pathway to ameliorate T1DM based on network pharmacology approach combined with experimental validation.

MATERIALS AND METHODS

A mouse-derived pancreatic islet β-cell line (MIN6) was used for the in vitro studies. An alloxan (ALX)-induced T1DM model in wild-type and Nrf2 knockout (Nrf2-/-) C57BL/6J mice were established for the in vivo experiments. The protective effects of FMNT against ALX-stimulated MIN6 cell injury were evaluated using MTT, EdU, apoptosis and comet assays. The levels of blood glucose in mice were measured by using a blood monitor and test strips. The protein expression was detected by Western blot analysis. Furthermore, the binding affinity of FMNT to Keap1 was evaluated using cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) assay, and solvent-induced protein precipitation (SIP) assay. The interaction pattern between FMNT and Keap1 was assessed by molecular docking and molecular dynamics simulation techniques.

RESULTS

Network pharmacology analysis revealed that FMNT exerted its therapeutic effect against T1DM by mainly regulating oxidative stress response-associated signaling molecules and pathways, such as Nrf2 regulating anti-oxidant/detoxification enzymes and Keap1-Nrf2 signaling pathway. The in vivo results showed that FMNT significantly deceased the ALX-induced high blood glucose levels and conversely increased the ALX-induced low insulin contents. In vitro, FMNT markedly protected MIN6 cells from ALX-induced cytotoxicity, proliferation inhibition and DNA damage and reduced the ALX-stimulated cell apoptosis. FMNT also inhibited ALX-induced overproduction of intracellular ROS to alleviate oxidative stress. In addition, FMNT could bind to Keap1 to notably activate the Keap1/Nrf2 signaling to upregulate Nrf2 expression and promote the Nrf2 translocation from the cytoplasm to the nucleus, resulting in enhancing the expression of antioxidant proteins HO-1 and NQO1. Inhibition of Keap1/Nrf2 signaling by ALX was also markedly abolished in the cells and mice exposed to FMNT. Moreover, these effects of FMNT in ameliorating T1DM were not observed in Nrf2-/- mice.

CONCLUSIONS

This study demonstrates that FMNT could bind to Keap1 to activate the Keap1/Nrf2 signaling to prevent intracellular ROS overproduction, thereby attenuating ALX-induced MIN6 cell injury and ameliorating ALX-stimulated T1DM. Results from this study might provide evidence and new insight into the therapeutic effect of FMNT and indicate that FMNT is a promising candidate agent for the treatment of T1DM in clinics.

Nrf2 activation: a key mechanism in stem cell exosomes-mediated therapies

Exosomes are nano-sized membrane extracellular vesicles which can be released from various types of cells. Exosomes originating from inflammatory or injured cells can have detrimental effects on recipient cells, while exosomes derived from stem cells not only facilitate the repair and regeneration of damaged tissues but also inhibit inflammation and provide protective effects against various diseases, suggesting they may serve as an alternative strategy of stem cells transplantation. Exosomes have a fundamental role in communication between cells, through the transfer of proteins, bioactive lipids and nucleic acids (like miRNAs and mRNAs) between cells. This transfer significantly impacts both the physiological and pathological functions of recipient cells. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, is able to mitigate damage caused by oxidative stress and inflammation through various signaling pathways. The positive effects resulting from the activation of the Nrf2 signaling pathway in different disorders have been documented in various types of literature. Studies have confirmed that exosomes derived from stem cells could act as Nrf2 effective agonists. However, limited studies have explored the Nrf2 role in the therapeutic effects of stem cell-derived exosomes. This review provides a comprehensive overview of the existing knowledge concerning the role of Nrf2 signaling pathways in the impact exerted by stem cell exosomes in some common diseases.

NRF2 in kidney physiology and disease

The role of NRF2 in kidney biology has received considerable interest over the past decade. NRF2 transcriptionally controls genes responsible for cellular protection against oxidative and electrophilic stress and has anti-inflammatory functions. NRF2 is expressed throughout the kidney and plays a role in salt and water handling. In disease, animal studies show that NRF2 protects against tubulointerstitial damage and reduces interstitial fibrosis and tubular atrophy, and may slow progression of polycystic kidney disease. However, the role of NRF2 in proteinuric glomerular diseases is controversial. Although the NRF2 inducer, bardoxolone methyl (CDDO-Me), increases glomerular filtration rate in humans, it has not been shown to slow disease progression in diabetic kidney disease and Alport syndrome. Furthermore, bardoxolone methyl was associated with negative effects on fluid retention, proteinuria, and blood pressure. Several animal studies replicate findings of worsened proteinuria and a more rapid progression of kidney disease, although considerable controversy exists. It is clear that further study is needed to better understand the effects of NRF2 in the kidney. This review summarizes the available data to clarify the promise and risks associated with targeting NRF2 activity in the kidney.

Kidney Fibrosis and Oxidative Stress: From Molecular Pathways to New Pharmacological Opportunities

Kidney fibrosis, diffused into the interstitium, vessels, and glomerulus, is the main pathologic feature associated with loss of renal function and chronic kidney disease (CKD). Fibrosis may be triggered in kidney diseases by different genetic and molecular insults. However, several studies have shown that fibrosis can be linked to oxidative stress and mitochondrial dysfunction in CKD. In this review, we will focus on three pathways that link oxidative stress and kidney fibrosis, namely: (i) hyperglycemia and mitochondrial energy imbalance, (ii) the mineralocorticoid signaling pathway, and (iii) the hypoxia-inducible factor (HIF) pathway. We selected these pathways because they are targeted by available medications capable of reducing kidney fibrosis, such as sodium-glucose cotransporter-2 (SGLT2) inhibitors, non-steroidal mineralocorticoid receptor antagonists (MRAs), and HIF-1alpha-prolyl hydroxylase inhibitors. These drugs have shown a reduction in oxidative stress in the kidney and a reduced collagen deposition across different CKD subtypes. However, there is still a long and winding road to a clear understanding of the anti-fibrotic effects of these compounds in humans, due to the inherent practical and ethical difficulties in obtaining sequential kidney biopsies and the lack of specific fibrosis biomarkers measurable in easily accessible matrices like urine. In this narrative review, we will describe these three pathways, their interconnections, and their link to and activity in oxidative stress and kidney fibrosis.

Investigation on Anti-diabetic Efficacy of a Cucurbitaceae Food Plant from the North-East Region of India: Exploring the Molecular Mechanism through Modulation of Oxidative Stress and Glycosylated Hemoglobin (HbA1c)

BACKGROUND

The medicinal plants of the Cucurbitaceae family, such as Solena heterophylla Lour. fruits, have significant ethnobotanical value and are readily accessible in North East India.

AIMS

We conducted a study on Solena heterophylla Lour. fruits to evaluate their anti-diabetic activity in vivo, standardize their HPTLC, and profile their metabolites using LC-QTOF-MS. We aimed to explore the molecular mechanism behind their effects on oxidative stress and glycosylated hemoglobin (HbA1c).

METHODS

Firstly, the ethyl acetate fraction of Solena heterophylla Lour. fruits was standardized using Cucurbitacin B as a standard marker by conducting HPTLC evaluation. Next, we delved into analyzing metabolite profiling. In addition, the standardized fraction was utilized in an experimental study to investigate the molecular mechanism of action in an in vivo high-fat diet and a low dose of streptozotocin-induced diabetic model.

RESULTS

We have reportedly identified 52 metabolites in the ethyl acetate fraction of Solena heterophylla (EASH). In the in vitro tests, it has been observed that this extract from plants possesses notable inhibitory properties against α-amylase and α-glucosidase. Solena heterophylla fruits with high levels of Cucurbitacin B (2.29% w/w) helped lower FBG levels in animals with EASH treatment. EASH treatment reduced HbA1c levels and normalized liver lipid peroxidation and antioxidant enzyme levels. SGOT, SGPT, and SALP serum enzyme levels also returned to normal.

CONCLUSION

Based on the current evaluation, it was found that EASH exhibited encouraging hypoglycemic effects in diabetic rats induced by a low dose of STZ and high-fat diet, which warrants further investigation.

Diabetic Neuropathy: An Overview of Molecular Pathways and Protective Mechanisms of Phytobioactives

Diabetic neuropathy (DN) is a common and debilitating complication of diabetes mellitus that affects the peripheral nerves and causes pain, numbness, and impaired function. The pathogenesis of DN involves multiple molecular mechanisms, such as oxidative stress, inflammation, and pathways of advanced glycation end products, polyol, hexosamine, and protein kinase C. Phytochemicals are natural compounds derived from plants that have various biological activities and therapeutic potential. Flavonoids, terpenes, alkaloids, stilbenes, and tannins are some of the phytochemicals that have been identified as having protective potential for diabetic neuropathy. These compounds can modulate various cellular pathways involved in the development and progression of neuropathy, including reducing oxidative stress and inflammation and promoting nerve growth and repair. In this review, the current evidence on the effects of phytochemicals on DN by focusing on five major classes, flavonoids, terpenes, alkaloids, stilbenes, and tannins, are summarized. This compilation also discusses the possible molecular targets of numerous pathways of DN that these phytochemicals modulate. These phytochemicals may offer a promising alternative or complementary approach to conventional drugs for DN management by modulating multiple pathological pathways and restoring nerve function.

Advances in oxidative stress in pathogenesis of diabetic kidney disease and efficacy of TCM intervention

Diabetic kidney disease (DKD) is a common complication of diabetes and has become the leading cause of end-stage kidney disease. The pathogenesis of DKD is complicated, and oxidative stress is considered as a core of DKD onset. High glucose can lead to increased production of reactive oxygen species (ROS) via the polyol, PKC, AGE/RAGE and hexosamine pathways, resulting in enhanced oxidative stress response. In this way, pathways such as PI3K/Akt, TGF-β1/p38-MAPK and NF-κB are activated, inducing endothelial cell apoptosis, inflammation, autophagy and fibrosis that cause histologic and functional abnormalities of the kidney and finally result in kidney injury. Presently, the treatment for DKD remains an unresolved issue. Traditional Chinese medicine (TCM) has unique advantages for DKD prevention and treatment attributed to its multi-target, multi-component, and multi-pathway characteristics. Numerous studies have proved that Chinese herbs (e.g., Golden Thread, Kudzuvine Root, Tripterygium glycosides, and Ginseng) and patent medicines (e.g., Shenshuaining Tablet, Compound Rhizoma Coptidis Capsule, and Zishen Tongluo Granule) are effective for DKD treatment. The present review described the role of oxidative stress in DKD pathogenesis and the effect of TCM intervention for DKD prevention and treatment, in an attempt to provide evidence for clinical practice.

Protective effect of eriodictyol against hyperglycemia-induced diabetic nephropathy in rats entails antioxidant and anti-inflammatory effects mediated by activating Nrf2

The pathogenesis of diabetic nephropathy (DN) involves cellular activation of oxidative stress and inflammation. Eriodictyol is a citrus-derived flavonoid with multiple pharmacological and protective effects in various conditions. The protective role of Eriodictyol against diabetes and diabetic nephropathy is less investigated. The current research aimed to explore the role of eriodictyol in protecting against DN prompted by streptozotocin in male rats and investigate some possible mechanisms of action. Diabetes was brought about in rats by an i.p injection of a lone dose (65 mg/kg). Five groups of rats were included (n = 8 each) as control (non-diabetic), eriodictyol (20 mg/kg, orally), STZ-diabetic, STZ + eriodictyol (20 mg/kg, orally), and STZ + eriodictyol (20 mg/kg, orally) + ML385 (30 µg/kg, i.p.). Kidney histology and the levels of some markers of kidney function, renal oxidative stress, and renal inflammation were analyzed in all groups of rats. Treatment with eriodictyol prevented the damage in the renal glomeruli and tubules and reduced renal immune cell infiltration in STZ-treated animals. It also spiked urinary creatinine excretion and reduced urine volume and urinary levels of albumin, monocyte chemoattractant protein 1 (MCP-1), urinary kidney injury molecule-1 (KIM-1), and nephrin in these diabetic rats. In addition, eriodictyol stimulated the nuclear protein accumulation of Nrf2 and boosted the expression of superoxide dismutase (SOD), glutathione (GSH), heme oxygenase-1 (HO-1), and catalase (CAT) in the diabetic rat kidneys. In concomitance, it reduced the nuclear levels of NF-κB and levels of interleukine-6 (IL-6), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) and attenuated the reduction in renal ATP levels and the increase in the mitochondria transition pore opening (mtTPT). However, the administration of eriodictyol did not affect rats' body weights and fasting glucose and insulin levels but significantly reduced serum levels of cholesterol, triglycerides, LDL-c, and oxidized LDL-c (ox-LDL-c). In conclusion, eriodictyol prevents STZ-induced nephropathy by a hypolipidemic effect and concomitant antioxidant and anti-inflammatory effects mediated by activating Nrf2/NF-κB/antioxidant axis.

A Review of the Potential of Nuclear Factor [Erythroid-Derived 2]-like 2 Activation in Autoimmune Diseases

An autoimmune disease is the consequence of the immune system attacking healthy cells, tissues, and organs by mistake instead of protecting them. Inflammation and oxidative stress (OS) are well-recognized processes occurring in association with acute or chronic impairment of cell homeostasis. The transcription factor Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is of major importance as the defense instrument against OS and alters anti-inflammatory activities related to different pathological states. Researchers have described Nrf2 as a significant regulator of innate immunity. Growing indications suggest that the Nrf2 signaling pathway is deregulated in numerous diseases, including autoimmune disorders. The advantageous outcome of the pharmacological activation of Nrf2 is an essential part of Nrf2-based chemoprevention and intervention in other chronic illnesses, such as neurodegeneration, cardiovascular disease, autoimmune diseases, and chronic kidney and liver disease. Nevertheless, a growing number of investigations have indicated that Nrf2 is already elevated in specific cancer and disease steps, suggesting that the pharmacological agents developed to mitigate the potentially destructive or transformative results associated with the protracted activation of Nrf2 should also be evaluated. The activators of Nrf2 have revealed an improvement in the progress of OS-associated diseases, resulting in immunoregulatory and anti-inflammatory activities; by contrast, the depletion of Nrf2 worsens disease progression. These data strengthen the growing attention to the biological properties of Nrf2 and its possible healing power on diseases. The evidence supporting a correlation between Nrf2 signaling and the most common autoimmune diseases is reviewed here. We focus on the aspects related to the possible effect of Nrf2 activation in ameliorating pathologic conditions based on the role of this regulator of antioxidant genes in the control of inflammation and OS, which are processes related to the progression of autoimmune diseases. Finally, the possibility of Nrf2 activation as a new drug development strategy to target pathogenesis is proposed.

Cinnamaldehyde alleviates doxorubicin-induced cardiotoxicity by decreasing oxidative stress and ferroptosis in cardiomyocytes

Although doxorubicin (DOX) is an efficient chemotherapeutic drug for human tumors, severe cardiotoxicity restricts its clinical use. Cinnamaldehyde (CA), a bioactive component isolated from Cinnamonum cassia, possesses potent anti-oxidative and anti-apoptotic potentials. The major aim of this study was to evaluate the protective role of CA against DOX-induced cardiotoxicity. To this end, cardiomyocyte injury models were developed using DOX-treated H9c2 cells and DOX-treated rats, respectively. Herein, we found that CA treatment increased cardiomyocyte viability and attenuated DOX-induced cardiomyocyte death in vitro. CA further protected rats against DOX-induced cardiotoxicity, as indicated by elevated creatine kinase (CK) and lactate dehydrogenase (LDH) levels, myocardium injury, and myocardial fibrosis. CA alleviated DOX-induced myocardial oxidative stress by regulating reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) levels. Mechanistically, CA markedly accelerated nuclear translocation of nuclear erythroid factor 2-related factor 2 (Nrf2) and increased heme oxygenase-1 (HO-1) expression. Consequently, CA decreased DOX-induced cardiomyocyte ferroptosis, while Erastin (a ferroptosis agonist) treatment destroyed the effect of CA on increasing cardiomyocyte viability. Taken together, the current results demonstrate that CA alleviates DOX-induced cardiotoxicity, providing a promising opportunity to increase the clinical application of DOX.

Reactive oxygen species, toxicity, oxidative stress, and antioxidants: chronic diseases and aging

A physiological level of oxygen/nitrogen free radicals and non-radical reactive species (collectively known as ROS/RNS) is termed oxidative eustress or "good stress" and is characterized by low to mild levels of oxidants involved in the regulation of various biochemical transformations such as carboxylation, hydroxylation, peroxidation, or modulation of signal transduction pathways such as Nuclear factor-κB (NF-κB), Mitogen-activated protein kinase (MAPK) cascade, phosphoinositide-3-kinase, nuclear factor erythroid 2-related factor 2 (Nrf2) and other processes. Increased levels of ROS/RNS, generated from both endogenous (mitochondria, NADPH oxidases) and/or exogenous sources (radiation, certain drugs, foods, cigarette smoking, pollution) result in a harmful condition termed oxidative stress ("bad stress"). Although it is widely accepted, that many chronic diseases are multifactorial in origin, they share oxidative stress as a common denominator. Here we review the importance of oxidative stress and the mechanisms through which oxidative stress contributes to the pathological states of an organism. Attention is focused on the chemistry of ROS and RNS (e.g. superoxide radical, hydrogen peroxide, hydroxyl radicals, peroxyl radicals, nitric oxide, peroxynitrite), and their role in oxidative damage of DNA, proteins, and membrane lipids. Quantitative and qualitative assessment of oxidative stress biomarkers is also discussed. Oxidative stress contributes to the pathology of cancer, cardiovascular diseases, diabetes, neurological disorders (Alzheimer's and Parkinson's diseases, Down syndrome), psychiatric diseases (depression, schizophrenia, bipolar disorder), renal disease, lung disease (chronic pulmonary obstruction, lung cancer), and aging. The concerted action of antioxidants to ameliorate the harmful effect of oxidative stress is achieved by antioxidant enzymes (Superoxide dismutases-SODs, catalase, glutathione peroxidase-GPx), and small molecular weight antioxidants (vitamins C and E, flavonoids, carotenoids, melatonin, ergothioneine, and others). Perhaps one of the most effective low molecular weight antioxidants is vitamin E, the first line of defense against the peroxidation of lipids. A promising approach appears to be the use of certain antioxidants (e.g. flavonoids), showing weak prooxidant properties that may boost cellular antioxidant systems and thus act as preventive anticancer agents. Redox metal-based enzyme mimetic compounds as potential pharmaceutical interventions and sirtuins as promising therapeutic targets for age-related diseases and anti-aging strategies are discussed.

A new NRF2 activator for the treatment of human metabolic dysfunction-associated fatty liver disease

Background & Aims

Oxidative stress triggers metabolic-associated fatty liver disease (MAFLD) and fibrosis. Previous animal studies demonstrated that the transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2), the master regulator of antioxidant response, protects against MAFLD and fibrosis. S217879, a next generation NRF2 activator has been recently shown to trigger diet-induced steatohepatitis resolution and to reduce established fibrosis in rodents. Our aim was to evaluate the therapeutic potential of S217879 in human MAFLD and its underlying mechanisms using the relevant experimental 3D model of patient-derived precision cut liver slices (PCLS).

Methods

We treated PCLS from 12 patients with varying stages of MAFLD with S217879 or elafibranor (peroxisome proliferator-activated receptor [PPAR]α/δ agonist used as a referent molecule) for 2 days. Safety and efficacy profiles, steatosis, liver injury, inflammation, and fibrosis were assessed as well as mechanisms involved in MAFLD pathophysiology, namely antioxidant response, autophagy, and endoplasmic reticulum-stress.

Results

Neither elafibranor nor S217879 had toxic effects at the tested concentrations on human PCLS with MAFLD. PPARα/δ and NRF2 target genes (pyruvate dehydrogenase kinase 4 [PDK4], fibroblast growth factor 21 [FGF21], and NAD(P)H quinone dehydrogenase 1 [NQO1], heme oxygenase 1 [HMOX1], respectively) were strongly upregulated in PCLS in response to elafibranor and S217879, respectively. Compared with untreated PCLS, elafibranor and S217879-treated slices displayed lower triglycerides and reduced inflammation (IL-1β, IL-6, chemokine (C-C motif) ligand 2 [CCL2]). Additional inflammatory markers (chemokine (C-C motif) ligand 5 [CCL5], stimulator of interferon genes [STING], intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1]) were downregulated by S217879. S217879 but not elafibranor lowered DNA damage (phospho-Histone H2A.X [p-H2A.X], RAD51, X-ray repair cross complementing 1 [XRCC1]) and apoptosis (cleaved caspase-3), and inhibited fibrogenesis markers expression (alpha smooth muscle actin [α-SMA], collagen 1 alpha 1 [COL1A1], collagen 1 alpha 2 [COL1A2]). Such effects were mediated through an improvement of lipid metabolism, activated antioxidant response and enhanced autophagy, without effect on endoplasmic reticulum-stress.

Conclusions

This study highlights the therapeutic potential of a new NRF2 activator for MAFLD using patient-derived PCLS supporting the evaluation of NRF2 activating strategies in clinical trials.

Impact and implications

Oxidative stress is a major driver of metabolic-associated fatty liver disease (MAFLD) development and progression. Nuclear factor (erythroid-derived 2)-like 2, the master regulator of the antioxidative stress response, is an attractive therapeutic target for the treatment of MAFLD. This study demonstrates that S217879, a new potent and selective nuclear factor (erythroid-derived 2)-like 2 activator, displays antisteatotic effects, lowers DNA damage, apoptosis, and inflammation and inhibits fibrogenesis in human PCLS in patients with MAFLD.

Sulforaphane: A nutraceutical against diabetes-related complications

There is an increasing interest in the use of nutraceuticals and plant-derived bioactive compounds from foods for their potential health benefits. For example, as a major active ingredient found from cruciferous vegetables like broccoli, there has been growing interest in understanding the therapeutic effects of sulforaphane against diverse metabolic complications. The past decade has seen an extensive growth in literature reporting on the potential health benefits of sulforaphane to neutralize pathological consequences of oxidative stress and inflammation, which may be essential in protecting against diabetes-related complications. In fact, preclinical evidence summarized within this review supports an active role of sulforaphane in activating nuclear factor erythroid 2-related factor 2 or effectively modulating AMP-activated protein kinase to protect against diabetic complications, including diabetic cardiomyopathy, diabetic neuropathy, diabetic nephropathy, as well as other metabolic complications involving non-alcoholic fatty liver disease and skeletal muscle insulin resistance. With clinical evidence suggesting that foods rich in sulforaphane like broccoli can improve the metabolic status and lower cardiovascular disease risk by reducing biomarkers of oxidative stress and inflammation in patients with type 2 diabetes. This information remains essential in determining the therapeutic value of sulforaphane or its potential use as a nutraceutical to manage diabetes and its related complications. Finally, this review discusses essential information on the bioavailability profile of sulforaphane, while also covering information on the pathological consequences of oxidative stress and inflammation that drive the development and progression of diabetes.

Transcription Factor NFE2L1 Decreases in Glomerulonephropathies after Podocyte Damage

Podocyte cellular injury and detachment from glomerular capillaries constitute a critical factor contributing to kidney disease. Notably, transcription factors are instrumental in maintaining podocyte differentiation and homeostasis. This study explores the hitherto uninvestigated expression of Nuclear Factor Erythroid 2-related Factor 1 (NFE2L1) in podocytes. We evaluated the podocyte expression of NFE2L1, Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2), and NAD(P)H:quinone Oxidoreductase (NQO1) in 127 human glomerular disease biopsies using multiplexed immunofluorescence and image analysis. We found that both NFE2L1 and NQO1 expressions were significantly diminished across all observed renal diseases. Furthermore, we exposed human immortalized podocytes and ex vivo kidney slices to Puromycin Aminonucleoside (PAN) and characterized the NFE2L1 protein isoform expression. PAN treatment led to a reduction in the nuclear expression of NFE2L1 in ex vivo kidney slices and podocytes.

Metabolic rewiring and epigenetic reprogramming in leptin receptor-deficient db/db diabetic nephropathy mice

BACKGROUND

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease in the United States. Emerging evidence suggests that mitochondrial metabolism and epigenetics play an important role in the development and progression of DN and its complications. For the first time, we investigated the regulation of cellular metabolism, DNA methylation, and transcriptome status by high glucose (HG) in the kidney of leptin receptor-deficient db/db mice using multi-omics approaches.

METHODS

The metabolomics was performed by liquid-chromatography-mass spectrometry (LC-MS), while epigenomic CpG methylation coupled with transcriptomic gene expression was analyzed by next-generation sequencing.

RESULTS

LC-MS analysis of glomerular and cortex tissue samples of db/db mice showed that HG regulated several cellular metabolites and metabolism-related signaling pathways, including S-adenosylmethionine, S-adenosylhomocysteine, methionine, glutamine, and glutamate. Gene expression study by RNA-seq analysis suggests transforming growth factor beta 1 (TGFβ1) and pro-inflammatory pathways play important roles in early DN. Epigenomic CpG methyl-seq showed HG revoked a list of differentially methylated regions in the promoter region of the genes. Integrated analysis of DNA methylation in the promoter regions of genes and gene expression changes across time points identified several genes persistently altered in DNA methylation and gene expression. Cyp2d22, Slc1a4, and Ddah1 are some identified genes that could reflect dysregulated genes involved in renal function and DN.

CONCLUSION

Our results suggest that leptin receptor deficiency leading to HG regulates metabolic rewiring, including SAM potentially driving DNA methylation and transcriptomic signaling that could be involved in the progression of DN.

Decreased DANCR contributes to high glucose-induced extracellular matrix accumulation in human renal mesangial cell via regulating the TGF-β/Smad signaling

Glomerulosclerosis is one of the major histopathologic changes in diabetic kidney diseases (DKD), which is characterized by excessive deposition of extracellular matrix (ECM) in the glomerulus mainly produced by mesangial cells in response to transforming growth factor-β (TGF-β) stimuli under diabetic conditions. Despite TGF-β has been implicated as a major pathogenic factor in the development of diabetic glomerulosclerosis, clinical trials of monoclonal antibodies against TGF-β failed to demonstrate therapeutic benefits. Thus, developing alternative therapeutic strategies to effectively block the TGF-β/Smad signaling could be of paramount importance for DKD treatment. Emerging evidence indicates that dysregulation of certain lncRNAs can lead to aberrant activation of TGF-β/Smad signaling. Herein, we identified a novel lncRNA, named DANCR, which could efficiently function as a negative regulator of TGF-β/Smad signaling in mesangial cells. Ectopic expression of DANCR could specifically block the activation of TGF-β/Smad signaling induced by high-glucose or TGF-β in human renal mesangial cells (HRMCs). Mechanistically, DANCR functions to stabilize nemo-like kinase (NLK) mRNA through interaction with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), resulting in enhanced phosphorylating on the linker region of activated Smad2/3 in the nucleus. Taken together, our data have uncovered an lncRNA-based regulatory modality of the TGF-β/Smad signaling and identified DANCR as an endogenous blocker of TGF-β/Smad signaling in HRMCs, which may represent a potential therapeutic target against the diabetic glomerulosclerosis.

Sulforaphane exhibits potent renoprotective effects in preclinical models of kidney diseases: A systematic review and meta-analysis

AIMS

Sulforaphane (SFN), a naturally occurring isothiocyanate found in cruciferous vegetables, has received extensive attention as a natural activator of the Nrf2/Keap1 cytoprotective pathway. In this review, a meta-analysis and systematic review of the renoprotective effects of SFN were performed in various preclinical models of kidney diseases.

MAIN METHODS

The primary outcome was the impact of SFN on renal function biomarkers (uremia, creatininemia, proteinuria or creatinine clearance) and secondary outcomes were kidney lesion histological indices/kidney injury molecular biomarkers. The effects of SFN were evaluated according to the standardized mean differences (SMDs). A random-effects model was applied to estimate the overall summary effect.

KEY FINDINGS

Twenty-five articles (out of 209 studies) were selected from the literature. SFN administration significantly increased creatinine clearance (SMD +1.88 95 % CI: [1.09; 2.68], P < 0.0001, I² = 0 %) and decreased the plasma creatinine (SMD -1.24, [-1.59; -0.88], P < 0.0001, I² = 36.0 %) and urea (SMD -3.22 [-4.42, -2.01], P < 0.0001, I² = 72.4 %) levels. SFN administration (median dose: 2.5 mg/kg, median duration: 3 weeks) significantly decreased urinary protein excretion (SMD -2.20 [-2.68; -1.73], P < 0.0001, I² = 34.1 %). It further improved two kidney lesion histological indices namely kidney fibrosis (SMD -3.08 [-4.53; -1.63], P < 0.0001, I² = 73.7 %) and glomerulosclerosis (SMD -2.24 [-2.96; -1.53], P < 0.0001, I² = 9.7 %) and decreased kidney injury molecular biomarkers (SMD -1.51 [-2.00; -1.02], P < 0.0001, I² = 0 %).

SIGNIFICANCE

These findings provide new insights concerning preclinical strategies for treating kidney disease or kidney failure with SFN supplements and should stimulate interest in clinical evaluations of SFN in patients with kidney disease.

17β-Estradiol Suppresses Gastric Inflammatory and Apoptotic Stress Responses and Restores nNOS-Mediated Gastric Emptying in Streptozotocin (STZ)-Induced Diabetic Female Mice

Gastroparesis (Gp) is a severe complication of diabetes mellitus (DM) observed predominantly in women. It is characterized by abnormal gastric emptying (GE) without mechanical obstruction in the stomach. Nitric oxide (NO) is an inhibitory neurotransmitter produced by neuronal nitric oxide synthase (nNOS). It plays a critical role in gastrointestinal (GI) motility and stomach emptying. Here, we wanted to demonstrate the protective effects of supplemental 17β-estradiol (E2) on NO-mediated gastric function. We showed E2 supplementation to alleviate oxidative and inflammatory stress in streptozotocin (STZ)-induced diabetic female mice. Our findings suggest that daily administration of E2 at therapeutic doses is beneficial for metabolic homeostasis. This restoration occurs via regulating and modulating the expression/function of glycogen synthase kinase-3β (GSK-3β), nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), Phase II enzymes, MAPK- and nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB)-mediated inflammatory cytokines (IL-1β, IL-6, TNFα, IGF-1), and gastric apoptotic regulators. We also showed E2 supplementation to elevate GCH-1 protein levels in female diabetic mice. Since GCH-1 facilitates the production of tetrahydrobiopterin (BH4, cofactor for nNOS), an increase in GCH-1 protein levels in diabetic mice may improve their GE and nitrergic function. Our findings provide new insights into the impact of estrogen on gastric oxidative stress and intracellular inflammatory cascades in the context of Gp.

Effects of incretin-based therapeutic agents including tirzepatide on renal outcomes in patients with type 2 diabetes: A systemic review and meta-analysis

Background

This meta-analysis was conducted to investigate the effects of incretin-based therapeutic agents, including the latest agent tirzepatide, on renal outcomes in patients with type 2 diabetes.

Methods

MEDLINE (via PubMed) and Cochrane databases were searched for studies involving incretin-based therapeutic agents up to July 2022. Randomized and controlled trials comparing incretin-based therapeutic agents with placebo or other antidiabetic agents, and reporting renal outcomes were selected. The inclusion criteria were items related to the effects on albuminuria and the kidney-specific composite outcomes. A network meta-analysis was conducted to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

Twelve trials consisting of 75,346 participants were included in this meta-analysis. Glucagon-like peptide-1 (GLP-1) receptor agonists reduced the risk of the kidney-specific composite outcome by 21% (HR 0.79, 95% CI 0.75-0.85), and worsening albuminuria by 24% (HR 0.76, 95% CI 0.71-0.82). In particular, the dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptor agonist tirzepatide remarkably reduced the risk of the kidney-specific composite outcome by 45% (HR 0.55, 95% CI 0.40-0.77), and worsening albuminuria by 62% (HR 0.38, 95% CI 0.24-0.61).

Conclusions

Among incretin-based therapeutic agents, tirzepatide was associated with a significantly reduced risk of diabetic kidney disease.

SIK2 protects against renal tubular injury and the progression of diabetic kidney disease

Despite optimal medical therapy, many patients with diabetic kidney disease (DKD) progress to end-stage renal disease. The identification of new biomarkers and drug targets for DKD is required for the development of more effective therapies. The apoptosis of renal tubular epithelial cells is a key feature of the pathogenicity associated with DKD. SIK2, a salt-inducible kinase, regulates important biological processes, such as energy metabolism, cell cycle progression and cellular apoptosis. In our current study, a notable decrease in the expression of SIK2 was detected in the renal tubules of DKD patients and murine models. Functional experiments demonstrated that deficiency or inactivity of SIK2 aggravates tubular injury and interstitial fibrosis in diabetic mice. Based on transcriptome sequencing, molecular mechanism exploration revealed that SIK2 overexpression reduces endoplasmic reticulum (ER) stress-mediated tubular epithelial apoptosis by inhibiting the histone acetyltransferase activity of p300 to activate HSF1/Hsp70. Furthermore, the specific restoration of SIK2 in tubules blunts tubular and interstitial impairments in diabetic and vancomycin-induced kidney disease mice. Together, these findings indicate that SIK2 protects against renal tubular injury and the progression of kidney disease, and make a compelling case for targeting SIK2 for therapy in DKD.

Bioactive Compounds as Inhibitors of Inflammation, Oxidative Stress and Metabolic Dysfunctions via Regulation of Cellular Redox Balance and Histone Acetylation State

Bioactive compounds (BCs) are known to exhibit antioxidant, anti-inflammatory, and anti-cancer properties by regulating the cellular redox balance and histone acetylation state. BCs can control chronic oxidative states caused by dietary stress, i.e., alcohol, high-fat, or high-glycemic diet, and adjust the redox balance to recover physiological conditions. Unique functions of BCs to scavenge reactive oxygen species (ROS) can resolve the redox imbalance due to the excessive generation of ROS. The ability of BCs to regulate the histone acetylation state contributes to the activation of transcription factors involved in immunity and metabolism against dietary stress. The protective properties of BCs are mainly ascribed to the roles of sirtuin 1 (SIRT1) and nuclear factor erythroid 2-related factor 2 (NRF2). As a histone deacetylase (HDAC), SIRT1 modulates the cellular redox balance and histone acetylation state by mediating ROS generation, regulating nicotinamide adenine dinucleotide (NAD+)/NADH ratio, and activating NRF2 in metabolic progression. In this study, the unique functions of BCs against diet-induced inflammation, oxidative stress, and metabolic dysfunction have been considered by focusing on the cellular redox balance and histone acetylation state. This work may provide evidence for the development of effective therapeutic agents from BCs.

The Regulatory Effect of Phytochemicals on Chronic Diseases by Targeting Nrf2-ARE Signaling Pathway

Redox balance is essential to maintain the body's normal metabolism. Once disrupted, it may lead to various chronic diseases, such as diabetes, neurodegenerative diseases, cardiovascular diseases, inflammatory diseases, cancer, aging, etc. Oxidative stress can cause or aggravate a series of pathological processes. Inhibition of oxidative stress and related pathological processes can help to ameliorate these chronic diseases, which have been found to be associated with Nrf2 activation. Nrf2 activation can not only regulate the expression of a series of antioxidant genes that reduce oxidative stress and its damage, but also directly regulate genes related to the above-mentioned pathological processes to counter the corresponding changes. Therefore, targeting Nrf2 has great potential for the prevention or treatment of chronic diseases, and many natural phytochemicals have been reported as Nrf2 activators although the defined mechanisms remain to be elucidated. This review article focuses on the possible mechanism of Nrf2 activation by natural phytochemicals in the prevention or treatment of chronic diseases and the regulation of oxidative stress. Moreover, the current clinical trials of phytochemical-originated drug discovery by targeting the Nrf2-ARE pathway were also summarized; the outcomes or the relationship between phytochemicals and chronic diseases prevention are finally analyzed to propose the future research strategies and prospective.

Klotho, Oxidative Stress, and Mitochondrial Damage in Kidney Disease

Reducing oxidative stress stands at the center of a prevention and control strategy for mitigating cellular senescence and aging. Kidney disease is characterized by a premature aging syndrome, and to find a modulator targeting against oxidative stress, mitochondrial dysfunction, and cellular senescence in kidney cells could be of great significance to prevent and control the progression of this disease. This review focuses on the pathogenic mechanisms related to the appearance of oxidative stress damage and mitochondrial dysfunction in kidney disease. In this scenario, the anti-aging Klotho protein plays a crucial role by modulating signaling pathways involving the manganese-containing superoxide dismutase (Mn-SOD) and the transcription factors FoxO and Nrf2, known antioxidant systems, and other known mitochondrial function regulators, such as mitochondrial uncoupling protein 1 (UCP1), B-cell lymphoma-2 (BCL-2), Wnt/β-catenin, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha), transcription factor EB, (TFEB), and peroxisome proliferator-activated receptor gamma (PPAR-gamma). Therefore, Klotho is postulated as a very promising new target for future therapeutic strategies against oxidative stress, mitochondria abnormalities, and cellular senescence in kidney disease patients.

Cinnamon: an aromatic condiment applicable to chronic kidney disease

Cinnamon, a member of the Lauraceae family, has been widely used as a spice and traditional herbal medicine for centuries and has shown beneficial effects in cardiovascular disease, obesity, and diabetes. However, its effectiveness as a therapeutic intervention for chronic kidney disease (CKD) remains unproven. The bioactive compounds within cinnamon, such as cinnamaldehyde, cinnamic acid, and cinnamate, can mitigate oxidative stress, inflammation, hyperglycemia, gut dysbiosis, and dyslipidemia, which are common complications in patients with CKD. In this narrative review, we assess the mechanisms by which cinnamon may alleviate complications observed in CKD and the possible role of this spice as an additional nutritional strategy for this patient group.

Renoprotective Effect of Thymoquinone against Streptozotocin-Induced Diabetic Nephropathy: Role of NOX2 and Nrf2 Signals

OBJECTIVE

Diabetic nephropathy is an unavoidable complication of chronic uncontrolled diabetes mellitus. The pathogenesis of diabetic nephropathy is multifactorial, and the development of an effective therapy remains to be elucidated. The aim of the present study was to assess the role of NOX2 and Nrf2 in the protective mechanism of thymoquinone (THQ) against streptozotocin (STZ)-induced diabetic nephropathy.

METHODS

Rats were injected with STZ (55 mg/kg) to induce diabetes. The diabetic rats were orally treated with THQ (10 mg/kg/day) for eight weeks.

RESULTS

STZ-treated rats exhibit an elevation of serum creatinine, serum urea, and creatinine clearance. The renal abnormalities were associated with increased NADPH oxidase isoform, NOX2 protein expression, and activity, along with elevated malondialdehyde (MDA). In addition, the tumor necrotic factor-alpha (TNF-α) level and nitric oxide (NO) bioavailability, as well as the transforming growth factor-beta (TGF)-β, were markedly increased. On the other hand, the nuclear factor-E2-related factor (Nrf2) protein expression was significantly reduced in diabetic rats compared to the control. However, treatment with THQ significantly reversed these alterations with subsequent ameliorating renal dysfunction and pathological abnormalities.

CONCLUSION

The present study demonstrates that THQ could protect against STZ-induced diabetic nephropathy by modulating the Nrf2/NOX2 signaling pathway.

Cinnamaldehyde Supplementation Reverts Endothelial Dysfunction in Rat Models of Diet-Induced Obesity: Role of NF-E2-Related Factor-2

Cinnamaldehyde (CN) is an activator of NF-E2-related factor 2 (Nrf2), which has the potential to reduce endothelial dysfunction, oxidative stress and inflammation in metabolic disorders. Our main purpose was to evaluate the effects of CN on vascular dysfunction in metabolic syndrome rats. Normal Wistar (W) rats were divided into eight groups: (1) Wistar (W) rats; (2) W rats fed with a high-fat diet (WHFD); (3) W rats fed with a sucrose diet (WS); (4) WHFD fed with a sucrose diet (WHFDS); (5) W treated with CN (WCn); (6) WS treated with CN (WSCn); (7) WHFD treated with CN (WHFDCn); (8) WHFDS treated with CN (WHFDSCn). CN treatment with 20 mg/kg/day was administered for 8 weeks. Evaluation of metabolic profile, inflammation, endothelial function, oxidative stress, eNOS expression levels and Nrf2 activation was performed. The metabolic dysfunction was greatly exacerbated in the WHFDS rats, accompanied by significantly higher levels of vascular oxidative stress, inflammation, and endothelial dysfunction. In addition, the WHFDS rats displayed significantly reduced activity of Nrf2 at the vascular level. CN significantly reverted endothelial dysfunction in the aortas and the mesenteric arteries. In addition, CN significantly decreased vascular oxidative damage, inflammation at vascular and perivascular level and up-regulated Nrf2 activity in the arteries of WHFDS rats. Cinnamaldehyde, an activator of Nrf2, can be used to improve metabolic profile, and to revert endothelial dysfunction in obesity and metabolic syndrome.

Role of STAT3 and NRF2 in Tumors: Potential Targets for Antitumor Therapy

Signal transducer and activator of transcription 3 (STAT3) and nuclear factor erythroid-derived 2-like 2 (NRF2, also known as NFE2L2), are two of the most complicated transcription regulators, which participate in a variety of physiological processes. Numerous studies have shown that they are overactivated in multiple types of tumors. Interestingly, STAT3 and NRF2 can also interact with each other to regulate tumor progression. Hence, these two important transcription factors are considered key targets for developing a new class of antitumor drugs. This review summarizes the pivotal roles of the two transcription regulators and their interactions in the tumor microenvironment to identify potential antitumor drug targets and, ultimately, improve patients' health and survival.

The roles of hydrogen sulfide in renal physiology and disease states

Hydrogen sulfide (H₂S), an endogenous gaseous signaling transmitter, has gained recognition for its physiological effects. In this review, we aim to summarize and discuss existing studies about the roles of H₂S in renal functions and renal disease as well as the underlying mechanisms. H₂S is mainly produced by four pathways, and the kidneys are major H₂S–producing organs. Previous studies have shown that H₂S can impact multiple signaling pathways via sulfhydration. In renal physiology, H₂S promotes kidney excretion, regulates renin release and increases ATP production as a sensor for oxygen. H₂S is also involved in the development of kidney disease. H₂S has been implicated in renal ischemia/reperfusion and cisplatin–and sepsis–induced kidney disease. In chronic kidney diseases, especially diabetic nephropathy, hypertensive nephropathy and obstructive kidney disease, H₂S attenuates disease progression by regulating oxidative stress, inflammation and the renin–angiotensin–aldosterone system. Despite accumulating evidence from experimental studies suggesting the potential roles of H₂S donors in the treatment of kidney disease, these results need further clinical translation. Therefore, expanding the understanding of H₂S can not only promote our further understanding of renal physiology but also lay a foundation for transforming H₂S into a target for specific kidney diseases.