Astilbin inhibits high glucose-induced autophagy and apoptosis through the PI3K/Akt pathway in human proximal tubular epithelial cells

Multifunctional dual-layer microneedles loaded with selenium-doped carbon quantum dots and Astilbin for ameliorating diabetic wound healing

Diabetic wounds (DW) represent a significant clinical challenge due to chronic inflammation, excessive oxidative stress, and impaired angiogenesis, all of which hinder effective tissue regeneration. Existing drug delivery systems often fail to achieve sustained and targeted therapeutic efficacy. In this study, we developed a novel dissolvable dual-layer methacrylated gelatin (GelMA) microneedle (MN) co-loading selenium-doped carbon quantum dots (Se-CQDs) and Astilbin (AST) for enhanced DW treatment. The outer layer, enriched with Se-CQDs, rapidly scavenges reactive oxygen species (ROS), effectively alleviating oxidative stress at the wound site. Sequentially, the inner layer releases AST, exerting potent anti-inflammatory and pro-angiogenic effects. Preliminary findings suggest these effects may involve the modulation of cytoskeletal dynamics and peroxisome function, contributing to endothelial cell migration and angiogenesis. This controlled, sequential release MN establishes a low-oxidative, anti-inflammatory microenvironment, thereby promoting angiogenesis and accelerating wound repair. The pioneering integration of selenium-doped quantum dots and AST-loaded hydrogels offers a synergistic therapeutic strategy, setting a new standard for advanced diabetic wound care with substantial clinical promise.

Research progress of effective components of traditional Chinese medicine in intervening apoptosis of renal tubular epithelial cells in diabetic kidney disease

ETHNOPHARMACOLOGICAL RELEVANCE

Apoptosis of renal tubular epithelial cells (RTECs) is a critical pathological feature of diabetic kidney disease (DKD), a primary contributor to end-stage renal disease (ESRD). Traditional Chinese medicine (TCM) has shown potential in modulating RTECs apoptosis and alleviating DKD progression, making it a promising area for further investigation.

AIM OF THE STUDY

This study aims to summarize the apoptotic pathways implicated in DKD, analyze existing research on the effects of TCM monomers and compounds on RTECs apoptosis, and elucidate the molecular mechanisms underlying these effects. Additionally, this study emphasizes the significant role of TCM in mitigating DKD progression.

MATERIALS AND METHODS

Relevant literature was systematically retrieved from ancient Chinese medicine texts and modern scientific databases, including CNKI, Web of Science, and PubMed, using keywords such as "Traditional Chinese Medicine", "Diabetic Kidney Disease", "Diabetic Nephropathy", "Renal Tubular Epithelial Cells", and "Apoptosis". The collected information was synthesized and analyzed.

RESULTS

This review systematically analyzed 187 relevant studies, focusing on the mechanisms and clinical applications of 16 TCM monomers and 20 TCM compounds in DKD treatment. Key bioactive compounds, such as berberine, astragaloside IV, and tanshinone IIA, have demonstrated renoprotective effects by mitigating oxidative stress and inflammation, as well as regulating critical signaling pathways, including PI3K/Akt, NF-κB, and TGF-β/Smad, to suppress RTECs apoptosis and decelerate DKD progression. Additionally, several TCM compounds have shown significant efficacy in clinical studies, reducing proteinuria and enhancing renal function, thereby reinforcing the therapeutic potential of TCM in DKD management.

CONCLUSIONS

RTECs apoptosis is a critical pathological feature of DKD. TCM exhibits significant therapeutic potential by intervening in this process through multiple pathways. This study highlights the ability of TCM to exert anti-apoptotic and renoprotective effects by modulating oxidative stress, inflammatory responses, and multiple cellular signaling pathways. The multi-component and multi-target characteristics of TCM offer a promising avenue for the development of novel therapeutic strategies. However, further rigorous research and high-quality clinical trials are required to validate its efficacy and elucidate its mechanisms of action.

Targeting programmed cell death in diabetic kidney disease: from molecular mechanisms to pharmacotherapy

Diabetic kidney disease (DKD), one of the most prevalent microvascular complications of diabetes, arises from dysregulated glucose and lipid metabolism induced by hyperglycemia, resulting in the deterioration of renal cells such as podocytes and tubular epithelial cells. Programmed cell death (PCD), comprising apoptosis, autophagy, ferroptosis, pyroptosis, and necroptosis, represents a spectrum of cell demise processes intricately governed by genetic mechanisms in vivo. Under physiological conditions, PCD facilitates the turnover of cellular populations and serves as a protective mechanism to eliminate impaired podocytes or tubular epithelial cells, thereby preserving renal tissue homeostasis amidst hyperglycemic stress. However, existing research predominantly elucidates individual modes of cell death, neglecting the intricate interplay and mutual modulation observed among various forms of PCD. In this comprehensive review, we delineate the diverse regulatory mechanisms governing PCD and elucidate the intricate crosstalk dynamics among distinct PCD pathways. Furthermore, we review recent advancements in understanding the pathogenesis of PCD and explore their implications in DKD. Additionally, we explore the potential of natural products derived primarily from botanical sources as therapeutic agents, highlighting their multifaceted effects on modulating PCD crosstalk, thereby proposing novel strategies for DKD treatment.

Targeting Autophagy: A Promising Therapeutic Strategy for Diabetes Mellitus and Diabetic Nephropathy

Diabetes mellitus (DM) significantly impairs patients' quality of life, primarily because of its complications, which are the leading cause of mortality among individuals with the disease. Autophagy has emerged as a key process closely associated with DM, including its complications such as diabetic nephropathy (DN). DN is a major complication of DM, contributing significantly to chronic kidney disease and renal failure. The intricate connection between autophagy and DM, including DN, highlights the potential for new therapeutic targets. This review examines the interplay between autophagy and these conditions, aiming to uncover novel approaches to treatment and enhance our understanding of their underlying pathophysiology. It also explores the role of autophagy in maintaining renal homeostasis and its involvement in the development and progression of DM and DN. Furthermore, the review discusses natural compounds that may alleviate these conditions by modulating autophagy.

Astilbin exerts a neuroprotective effect by upregulating the signaling of nuclear NF-E2-related factor 2 in vitro

Objective

The present study aims to evaluate the impact of Astilbin (AST) on cortical neuron survival in vitro under conditions of oxygen-glucose deprivation and reoxygenation (OGD/R) and determine the role of NF-E2-related factor 2 (Nrf2) in this process.

Methods

Primary neurons were pre-treated with various concentrations of AST for 8 h before OGD induction. Cell viability and lactate dehydrogenase (LDH) leakage were assessed to determine the optimal concentration. Biomarkers related to oxidative stress, antioxidant enzyme activities, and apoptosis were evaluated at 24 h post-OGD/R. To investigate the involvement of Nrf2 in AST-mediated neuroprotection, we conducted molecular docking and microscale thermophoresis analyses, as well as examined the expression levels of Nrf2 and its regulatory genes including heme oxygenase-1(HO-1), (NAD(P)H: quinone oxidoreductase 1 (NQO-1), and peroxiredoxin 1 (Prdx1). Additionally, lentivirus-mediated knockdown of Nrf2 and overexpression of Nrf2 with L-sulforaphane (SFN) were performed, followed by an assessment of cell viability, oxidative stress, antioxidant enzyme activities and apoptosis.

Results

Pre-treatment with AST reduced oxidative stress levels while increasing antioxidant enzyme activities and mitigating neuronal apoptosis. After OGD/R exposure, AST upregulated nuclear Nrf2 expression and increased the expression of HO-1, NQO-1 and Prdx1 in the cytoplasm. However, the knockdown of Nrf2 abolished the antioxidative and protective effects exerted by AST treatment. Conversely, combining AST with the Nrf2 agonist SFN demonstrated an enhancement in the protective effects provided by AST. These results demonstrate that Nrf2-dependent antioxidant responses contribute to AST-induced tolerance against neuronal injury caused by OGD/R injury.

Conclusions

Overall findings support the ability of AST to protect primary neurons from OGD/R-induced damage through activation of Nrf2-dependent antioxidant responses.

DMDD, isolated from Averrhoa carambola L., ameliorates diabetic nephropathy by regulating endoplasmic reticulum stress-autophagy crosstalk

BACKGROUND

Studies have shown that Averrhoa carambola L. possesses therapeutic potential for diabetes and related complications. However, the specific beneficial effects and molecular mechanisms of 2-dodecyl-6-meth-oxycyclohexa-2,5-diene-1,4-dione (DMDD) isolated from Averrhoa carambola L. on diabetic nephropathy (DN) require further investigation.

METHODS

80 C57BL/6 J male mice were subjected to a 1-week adaptive feeding, followed by a high-fat diet and intraperitoneal injection of 100 mg/kg streptozotocin (STZ) to construct an in vivo DN model. Additionally, human renal proximal tubular epithelial cells (HK-2) induced by high glucose (HG) were used as an in vitro DN model. The expression levels of epithelial-mesenchymal transition (EMT), endoplasmic reticulum stress (ERS), and autophagy-related proteins in renal tubular cells were detected by Western Blot, flow cytometry, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA) staining. Transcriptome analysis revealed was conducted to elucidate the specific mechanism of by which DMDD mitigates DN by inhibiting ERS and autophagy. HK-2 cells were transfected with IRE1α overexpression lentivirus to reveal the role of IRE1α overexpression in HG-induced HK-2.

RESULTS

The experimental data showed that DMDD significantly reduced blood glucose levels and improved renal pathological alterations in DN mice. Additionally, DMDD inhibited the calcium (Ca2+) pathway, manifested by decreased autophagosome formation and downregulation of LC3II/I, Beclin-1, and ATG5 expression. Moreover, in HG-induced HK-2 cells, DMDD suppressed the overexpression of GRP78, CHOP, LC3II/I, Beclin1, and ATG5. Notably, IRE1α overexpression significantly increased autophagy incidence; however, DMDD treatment subsequently reduced the expression of LC3II/I, Beclin1, and ATG5.

CONCLUSION

DMDD effectively inhibits excessive ERS and autophagy, thereby reducing renal cell apoptosis through the IRE1α pathway and Ca 2+ pathway.

Natural compounds improve diabetic nephropathy by regulating the TLR4 signaling pathway

Diabetic nephropathy (DN), a severe complication of diabetes, is widely recognized as a primary contributor to end-stage renal disease. Recent studies indicate that the inflammation triggered by Toll-like receptor 4 (TLR4) is of paramount importance in the onset and progression of DN. TLR4 can bind to various ligands, including exogenous ligands such as proteins and polysaccharides from bacteria or viruses, as well as endogenous ligands such as biglycan, fibrinogen, and hyaluronan. In DN, the expression or release of TLR4-related ligands is significantly elevated, resulting in excessive TLR4 activation and increased production of proinflammatory cytokines through downstream signaling pathways. This process is closely associated with the progression of DN. Natural compounds are biologically active products derived from natural sources that have advantages in the treatment of certain diseases. Various types of natural compounds, including alkaloids, flavonoids, polyphenols, terpenoids, glycosides, and polysaccharides, have demonstrated their ability to improve DN by affecting the TLR4 signaling pathway. In this review, we summarize the mechanism of action of TLR4 in DN and the natural compounds that can ameliorate DN by modulating the TLR4 signaling pathway. We specifically highlight the potential of compounds such as curcumin, paclitaxel, berberine, and ursolic acid to inhibit the TLR4 signaling pathway, which provides an important direction of research for the treatment of DN.

Molecular mechanisms and therapeutic potential of natural flavonoids in diabetic nephropathy: Modulation of intracellular developmental signaling pathways

Recognized as a common microvascular complication of diabetes mellitus (DM), diabetic nephropathy (DN) is the principal cause of chronic end-stage renal disease (ESRD). Patients with diabetes have an approximately 25% risk of developing progressive renal disease. The underlying principles of DN control targets the dual outcomes of blood glucose regulation through sodium glucose cotransporter 2 (SGLT 2) blockade and hypertension management through renin-angiotensin-aldosterone inhibition. However, these treatments are ineffective in halting disease progression to kidney failure and cardiovascular comorbidities. Recently, the dysregulation of subcellular signaling pathways has been increasingly implicated in DN pathogenesis. Natural compounds are emerging as effective and side-effect-free therapeutic agents that target intracellular pathways. This narrative review synthesizes recent insights into the dysregulation of maintenance pathways in DN, drawing from animal and human studies. To compile this review, articles reporting DN signaling pathways and their treatment with natural flavonoids were collected from PubMed, Cochrane Library Web of Science, Google Scholar and EMBASE databases since 2000. As therapeutic interventions are frequently based on the results of clinical trials, a brief analysis of data from current phase II and III clinical trials on DN is discussed.

Quercetin prevented diabetic nephropathy by inhibiting renal tubular epithelial cell apoptosis via the PI3K/AKT pathway

Diabetic nephropathy (DN) is the most common and serious complication of diabetes, posing a significant threat to human health. Currently, safe and effective preventive strategies for DN are lacking. The study aimed to explore the preventive effect and the underlying mechanism of quercetin against DN. In the in vivo experiments, we established a mouse model of type 2 diabetes mellitus (T2DM) induced by a combination of high-fat diet (HFD) and streptozotocin (STZ) to explore the preventive effect of quercetin on DN and its protective role against renal tubular epithelial cell apoptosis. Subsequently, in vitro experiments using human tubular epithelial cells (HK-2 cells) were conducted to further validate the protective effects of quercetin on renal tubular epithelial cell apoptosis. Additionally, we employed RNA sequencing analysis (RNA-seq) and network pharmacology analysis to comprehensively elucidate the molecular mechanisms involved. In vivo, we observed a significant increase in the ratio of urinary microalbumin to creatinine in diabetic mice compared to control mice, accompanied by the activation of renal tubular epithelial cell apoptosis. Remarkably, all of these changes were reversed after quercetin treatment. In vitro, high-glucose-induced apoptosis in HK-2 cells was significantly attenuated by quercetin. Subsequent RNA sequencing analysis and network pharmacology analysis revealed that quercetin was most likely to inhibit high-glucose-induced HK-2 cell apoptosis through the PI3K/AKT signaling pathway. Western Blotting results further demonstrated that quercetin could inhibit the activation of the PI3K/AKT signaling pathway in HK-2 cells induced by high glucose. Our results supported that quercetin could prevent DN by inhibiting tubular epithelial cell apoptosis via the PI3K/AKT pathway. Quercetin might be a promising candidate for the prevention of DN.

Jiawei Shengjiangsan's Effect on Renal Injury in Diabetic Nephropathy Mice is Investigated via the PI3K/Akt/NF-κB Signaling Pathway

Purpose

This study aimed to investigate the intervention mechanism of Jiawei Shengjiangsan (JWSJS) on kidney injury in diabetic nephropathy mice.

Methods

Thirty 8-week-old db/db mice were randomly divided into five groups: model group, Perindopril group, and JWSJS low-, medium-, and high-dose groups (n=6 per group) based on body weight. Additionally, a blank control group was established consisting of 6 db/m mice aged 8 weeks. The blank and model groups received daily intragastric administration of 7g/kg/d pure water. The remaining groups were assigned to JWSJS low (3.5g/kg/d), medium (7g/kg/d), high (14g/kg/d) dosage groups, and perindopril positive control group (0.48mg/kg/d) for 12 weeks. Post-experiment, serum creatinine (SCr) and blood urea nitrogen (BUN) were analyzed using an automatic biochemical analyzer. Enzyme-linked immunosorbent assay (ELISA) measured 24-hour urinary albumin, neutrophil gelatinase-associated lipocalin (NGAL), TNF-α, IL-1β, VCAM-1, MCP-1, and HbA1c. Western blot assessed the protein expressions of p-PI3K, p-Akt, and p-NF-κB p65, while pathological kidney changes were observed.

Results

Compared to the blank group, the model group exhibited increased SCr, BUN, 24-hour urinary albumin, serum NGAL, TNF-α, IL-1β, VCAM-1, MCP-1, HbA1c, p-PI3K, and p-Akt, alongside increased p-NF-κB p65 expression, indicating significant kidney pathology. After treatment, the JWSJS group showed decreased SCr, BUN, 24-hour urinary microalbumin, NGAL, HbA1c, TNF-α, IL-1β, VCAM-1, MCP-1 levels, increased p-PI3K and p-Akt expression (P<0.05), and reduced p-NF-κB p65 content (P<0.05). Histopathological analysis revealed that JWSJS ameliorated renal tubular epithelial cell damage, glomerular capillary and basement membrane injuries, and facilitated the repair of damaged podocytes in diabetic nephropathy mice.

Conclusion

JWSJS demonstrated efficacy in reducing renal inflammation in diabetic nephropathy mice, with its mechanism likely associated with the inhibition of the PI3K/Akt/NF-κB signaling pathway.

Targeting autophagy with natural products as a potential therapeutic approach for diabetic microangiopathy

As the quality of life improves, the incidence of diabetes mellitus and its microvascular complications (DMC) continues to increase, posing a threat to people's health and wellbeing. Given the limitations of existing treatment, there is an urgent need for novel approaches to prevent and treat DMC. Autophagy, a pivotal mechanism governing metabolic regulation in organisms, facilitates the removal of dysfunctional proteins and organelles, thereby sustaining cellular homeostasis and energy generation. Anomalous states in pancreatic β-cells, podocytes, Müller cells, cardiomyocytes, and Schwann cells in DMC are closely linked to autophagic dysregulation. Natural products have the property of being multi-targeted and can affect autophagy and hence DMC progression in terms of nutrient perception, oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis. This review consolidates recent advancements in understanding DMC pathogenesis via autophagy and proposes novel perspectives on treating DMC by either stimulating or inhibiting autophagy using natural products.

Novel insight into the therapeutical potential of flavonoids from traditional Chinese medicine against cerebral ischemia/reperfusion injury

Cerebral ischemia/reperfusion injury (CIRI) is a major contributor to poor prognosis of ischemic stroke. Flavonoids are a broad family of plant polyphenols which are abundant in traditional Chinese medicine (TCM) and have beneficial effects on several diseases including ischemic stroke. Accumulating studies have indicated that flavonoids derived from herbal TCM are effective in alleviating CIRI after ischemic stroke in vitro or in vivo, and exhibit favourable therapeutical potential. Herein, we systematically review the classification, metabolic absorption, neuroprotective efficacy, and mechanisms of TCM flavonoids against CIRI. The literature suggest that flavonoids exert potential medicinal functions including suppressing excitotoxicity, Ca2+ overloading, oxidative stress, inflammation, thrombin's cellular toxicity, different types of programmed cell deaths, and protecting the blood-brain barrier, as well as promoting neurogenesis in the recovery stage following ischemic stroke. Furthermore, we identified certain matters that should be taken into account in future research, as well as proposed difficulties and opportunities in transforming TCM-derived flavonoids into medications or functional foods for the treatment or prevention of CIRI. Overall, in this review we aim to provide novel ideas for the identification of new prospective medication candidates for the therapeutic strategy against ischemic stroke.

Comparative study of the interaction mechanism of astilbin, isoastilbin, and neoastilbin with CYP3A4

The interactions of human CYP3A4 with three selected isomer flavonoids, such as astilbin, isoastilbin and neoastilbin, were clarified using spectral analysis, molecular docking, and molecular dynamics simulation. During binding with the three flavonoids, the intrinsic fluorescence of CYP3A4 was statically quenched in static mode with nonradiative energy conversion. The fluorescence and ultraviolet/visible (UV/vis) data revealed that the three flavonoids had a moderate and stronger binding affinity with CYP3A4 due to the order of the Ka1 and Ka2 values ranging from 104 to 105  L·mol-1 . In addition, astilbin had the highest affinity with CYP3A4, then isoastilbin and neoastilbin, at the three experimental temperatures. Multispectral analysis confirmed that binding of the three flavonoids resulted in clear changes in the secondary structure of CYP3A4. It was found from fluorescence, UV/vis and molecular docking analyses that these three flavonoids strongly bound to CYP3A4 by means of hydrogen bonds and van der Waals forces. The key amino acids around the binding site were also elucidated. Furthermore, the stabilities of the three CYP3A4 complexes were evaluated using molecular dynamics simulation.

Attenuative effect of astilbin on polystyrene microplastics induced testicular damage: Biochemical, spermatological and histopathological-based evidences

Polystyrene microplastics (PS-MPs) are the potential environmental pollutants that possess the ability to induce testicular damage. Astilbin (ASB) is a dihydroflavonol, abundantly reported in multiple plants that has various pharmacological properties. This research elucidated the mitigative potential of ASB against PS-MPs-instigated testicular toxicity. 48 adult male rats (200 ± 10 g) were distributed into 4 groups (n = 12): control, PS-MPs received (0.01 mg/kg), PS-MPs + ASB received (0.01 mg/kg + 20 mg/kg) and ASB supplemented group (20 mg/kg). After 56th day of the trial, animals were sacrificed and testes were harvested for the estimation of biochemical, hormonal, spermatogenic, steroidogenic, apoptotic and histological profiles. PS-MPs intoxication significantly (P < 0.05) lowered glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione reductase (GSR) as well as catalase (CAT) activities, whereas elevated MDA as well as ROS levels. Besides, the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), nuclear factor kappa-B (NF-κB) along with cyclooxygenase-2 (COX-2) activity were raised. PS-MPs treatment reduced luteinizing hormone (LH), plasma testosterone and follicle-stimulating hormone (FSH) level besides decreased epididymal sperm number, viability, motility as well as the count of HOS coil-tailed spermatozoa and increased sperm morphological irregularities. PS-MPs exposure lowered steroidogenic enzymes (17β-HSD, 3β-HSD and StAR protein along with Bcl-2 expression, besides increasing Caspase-3 and Bax expressions and histopathological alterations in testicular tissues. However, ASB treatment significantly reversed PS-MPs mediated damage. In conclusion, ASB administration is protective against PS-MPs-instigated testicular damage owing to its anti-inflammatory, anti-apoptotic, antioxidant and androgenic nature.

Chinese herbal medicine and its active compounds in attenuating renal injury via regulating autophagy in diabetic kidney disease

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease worldwide, and there is a lack of effective treatment strategies. Autophagy is a highly conserved lysosomal degradation process that maintains homeostasis and energy balance by removing protein aggregates and damaged organelles. Increasing evidence suggests that dysregulated autophagy may contribute to glomerular and tubulointerstitial lesions in the kidney under diabetic conditions. Emerging studies have shown that Chinese herbal medicine and its active compounds may ameliorate diabetic kidney injury by regulating autophagy. In this review, we summarize that dysregulation or insufficiency of autophagy in renal cells, including podocytes, glomerular mesangial cells, and proximal tubular epithelial cells, is a key mechanism for the development of DKD, and focus on the protective effects of Chinese herbal medicine and its active compounds. Moreover, we systematically reviewed the mechanism of autophagy in DKD regulated by Chinese herb compound preparations, single herb and active compounds, so as to provide new drug candidates for clinical treatment of DKD. Finally, we also reviewed the candidate targets of Chinese herbal medicine regulating autophagy for DKD. Therefore, further research on Chinese herbal medicine with autophagy regulation and their targets is of great significance for the realization of new targeted therapies for DKD.

Protective Effects of Astilbin Against Cadmium-Induced Apoptosis in Chicken Kidneys via Endoplasmic Reticulum Stress Signaling Pathway

Cadmium (Cd) can cause endoplasmic reticulum stress (ERS) and apoptosis in animals. The kidney is an organ seriously affected by Cd because it can accumulate metal ions. Astilbin (ASB) is a dihydroflavonol rhamnoside, which has an anti-renal injury effect. This study aimed to evaluate the protective effect of ASB on Cd-induced ERS and apoptosis in the chicken kidney. In this study, a total of 120 1-day-old chickens were randomly divided into 4 groups. Chickens were fed with a basic diet (Con group), ASB 40 mg/kg (ASB group), CdCl₂ 150 mg/kg + ASB 40 mg/kg (ASB/Cd group), and CdCl₂ 150 mg/kg (Cd group) for 90 days. The results showed that Cd exposure induced pathological and ultrastructural damages and apoptosis in chicken kidneys. Compared with the Con group, metallothionein (MT1/MT2) level, nitric oxide (NO) content, inducible nitric oxide synthase (iNOS) activity, ERS-related genes 78-kDa glucose-regulated protein (Grp78), protein kinase PKR-like endoplasmic reticulum kinase (Perk), activating transcription factor 4 (Atf4) and CAAT/enhancer-binding protein (C/EBP) homologous protein (Chop), and pro-apoptotic gene B-cell lymphoma 2 (Bcl-2)-associated X (Bax), caspase-12, caspase-9, caspase-3 expression levels, and apoptotic rate were significantly increased in the Cd group. The expression level of Bcl-2 was significantly decreased in the Cd group. ASB/Cd combined treatment significantly improves the damage of chicken kidneys by ameliorating Cd-induced kidney ERS and apoptosis. Cd can cause the disorder of the GRP78 signal axis, activate the PERK-ATF4-CHOP pathway, aggravate the structural damage and dysfunction of ER, and promote the apoptosis of chicken kidneys, while the above changes were significantly alleviated in the ASB/Cd group. The results showed that ASB antagonizes the negative effects of Cd and against Cd-induced apoptosis in chicken kidneys via ERS signaling pathway.

The critical role of dysregulated autophagy in the progression of diabetic kidney disease

Diabetic kidney disease (DKD) is one of the major public health problems in society today. It is a renal complication caused by diabetes mellitus with predominantly microangiopathy and is a major cause of end-stage renal disease (ESRD). Autophagy is a metabolic pathway for the intracellular degradation of cytoplasmic products and damaged organelles and plays a vital role in maintaining homeostasis and function of the renal cells. The dysregulation of autophagy in the hyperglycaemic state of diabetes mellitus can lead to the progression of DKD, and the activation or restoration of autophagy through drugs is beneficial to the recovery of renal function. This review summarizes the physiological process of autophagy, illustrates the close link between DKD and autophagy, and discusses the effects of drugs on autophagy and the signaling pathways involved from the perspective of podocytes, renal tubular epithelial cells, and mesangial cells, in the hope that this will be useful for clinical treatment.

TSPAN8 alleviates high glucose-induced apoptosis and autophagy via targeting mTORC2

TSPAN8 mediates signal transduction from extracellular cues and regulates cell development, activation, growth, and motility. However, whether TSPAN8 is involved in the progression of diabetic nephropathy (DN) remains unclear. This study aimed to explore the potential functional roles of TSPAN8 in regulating autophagy and apoptosis of HK-2 cells induced by high glucose (HG). RT-PCR and western blot analysis (WB) were employed to detect TSPAN8 levels in the blood samples of DN patients as well as in HG-induced HK-2 cells. Cell proliferation of HK-2 cells was examined by CCK-8 assay, and apoptosis was analyzed by flow cytometry. The functional role of TSPAN8 was evaluated by the transfection of TSPAN8 expression plasmid. Results showed that TSPAN8 level was significantly reduced in the blood samples of DN patients and HG-induced HK-2 cell lines. TSPAN8 overexpression rescued HG-induced apoptosis in HK-2 cells. TSPAN8 could form a complex with Rictor and mTORC2. TSPAN8 overexpression suppressed HG-induced autophagy in HK-2 cells, which was dependent on mTOR activity. In conclusion, the present study showed that TSPAN8 mitigates HG-induced autophagy and apoptosis in HK-2 cells, which may serve as candidate target for DN treatment.

Molecular Insight into the Binding of Astilbin with Human Serum Albumin and Its Effect on Antioxidant Characteristics of Astilbin

Astilbin is a dihydroflavonol glycoside identified in many natural plants and functional food with promising biological activities which is used as an antioxidant in the pharmaceutical and food fields. This work investigated the interaction between astilbin and human serum albumin (HSA) and their effects on the antioxidant activity of astilbin by multi-spectroscopic and molecular modeling studies. The experimental results show that astilbin quenches the fluorescence emission of HSA through a static quenching mechanism. Astilbin and HSA prefer to bind at the Site Ⅰ position, which is mainly maintained by electrostatic force, hydrophobic and hydrogen bonding interactions. Multi-spectroscopic and MD results indicate that the secondary structure of HSA could be changed because of the interaction of astilbin with HSA. DPPH radical scavenging assay shows that the presence of HSA reduces the antioxidant capacity of astilbin. The explication of astilbin–HSA binding mechanism will provide insights into clinical use and resource development of astilbin in food and pharmaceutical industries.

Astilbin Activates the Reactive Oxidative Species/PPARγ Pathway to Suppress Effector CD4+ T Cell Activities via Direct Binding With Cytochrome P450 1B1

Astilbin, as a compound of flavonoids, exerts anti-inflammation, antioxidation, and immune-suppression activities. Decreased activation of NF-κB and p38 MAPK and increased activation of SOCS3 and AMPK have been found in astilbin-treated cells. However, what molecules are docked by astilbin to initiate signaling cascades and result in functional changes remains unknown. In the study, we found that astilbin efficiently suppressed TNF-α production and increased CCR9 and CD36 expression of CD4⁺ T cells. In vivo administration of astilbin repressed the occurrence of type 1 diabetes mellitus in non-obese diabetic mice. The PPARγ/SOCS3, PPARγ/PTEN, and PPARγ/AMPK signaling pathways were substantially activated and played key roles in astilbin-induced downregulation of CD4⁺ T cell functions. Transcriptome sequencing results confirmed the changes of signaling molecules involved in the immune system, inflammatory responses, and indicated variations of multiple enzymes with oxidant or antioxidant activities. Astilbin directly induced cytoplasmic ROS production of CD4⁺ T cells ex vivo, but had no effects on mitochondrial ROS and mitochondrial weight. When cellular ROS was depleted, astilbin-treated CD4⁺ T cells remarkably reversed the expression of TNF-α, IFN-γ, CCR9, CD36, and signaling molecules (PPARγ, PTEN, p-AMPK, and SOCS3). Based on bioinformatics, two P450 enzymes (CYP1B1 and CYP19A1) were selected as candidate receptors for astilbin. CYP1B1 was identified as a real docking protein of astilbin in ROS production by AutoDock Vina software analysis and surface plasmon resonance assay. Collectively, astilbin downregulates effector CD4⁺ T cell activities via the CYP1B1/ROS/PPARγ pathway, which firmly supports its potential use in the treatment of inflammation.

Astilbin attenuates apoptosis induced by cadmium through oxidative stress in carp (Cyprinus carpio L.) head kidney lymphocyte

As a kind of environmental pollutant, heavy metal Cadmium (Cd) exists widely in the environment. It is well known that Cd can accumulate and cause damage in liver, kidney and other organs. However, there are few studies on the immune cytotoxicity of Cd to fish. In particular, there are few studies on the toxicity of Cd to the head kidney lymphocytes of common carp. In order to further explore these mechanisms, we established an Cd exposure model in vitro. At the same time, we used the natural antioxidant astilbin (AST) to treat the cells to study its antagonistic effect on the toxicity of Cd. After exposure to Cd, the level of oxidative stress in head kidney lymphocytes increased, and the mRNA and protein expression of apoptosis-related markers Fas, FADD, Caspase8 and Caspase3 increased significantly (P < 0.05), which led to lymphocytes apoptosis. Hoechst staining and AO/EB staining also showed that the level of apoptosis increased after exposure to Cd. This is consistent with our previous research results. AST treatment reduced oxidative stress and apoptosis induced by Cd. In addition, oxidative stress inhibitor NAC could also reduce head kidney lymphocytes apoptosis induced by Cd, indicating that oxidative stress was involved in this process. Our results suggested that AST can alleviate the apoptosis of carp head kidney lymphocytes induced by Cd through oxidative stress. This study enriches the theoretical mechanism of Cd toxicity to fish head kidney lymphocytes, and puts forward a method to solve the toxicity of Cd, which provides a theoretical and research basis for the in vivo study of animal models in the future.

Notch3-Mediated mTOR Signaling Pathway Is Involved in High Glucose-Induced Autophagy in Bovine Kidney Epithelial Cells

It is reported that Notch3 and mTOR signaling pathways are involved in autophagy, and both can be activated by high glucose (HG). However, the relationship between Notch3 and mTOR and how Notch3 affects mTOR to regulate HG-induced autophagy in bovine kidney epithelial cells is still unclear. The purpose of this study is to explore how Notch3 affects mTOR to modulate HG-induced autophagy in bovine kidney cells. Our results showed that HG treatment significantly decreased the cell viability of MDBK cells in a dose-dependent manner. HG treatment significantly increased the expression of LC3-II/I ratio and Beclin1 protein and significantly decreased the expression of p62 protein. Consistently, LC3 fluorescence signal formation was detected by immunofluorescence in both dose and time-dependent manners. In addition, HG treatment significantly increased the expression of Notch3 protein and decreased the expression of the p-mTOR protein in both dose and time-dependent manners. Inhibition of Notch3 upregulated the expression of p-mTOR and p62 protein, and downregulated the expression of LC3-II/I ratio and Beclin1 protein. Besides, the function of Notch3 was investigated. In this study, inhibition of Notch3 activity significantly increased the viability of HG-stimulated MDBK cells. In summary, our results revealed that the Notch3-mediated mTOR signaling pathway was involved in HG-induced autophagy in MDBK cells.

PINK1 mediated mitophagy attenuates early apoptosis of gingival epithelial cells induced by high glucose

BACKGROUND

Oxidative stress mediated by hyperglycemia damages cell-reparative processes such as mitophagy. Down-regulation of mitophagy is considered to be a susceptible factor for diabetes mellitus (DM) and its complications. However, the role of mitophagy in DM-associated periodontitis has not been fully elucidated. Apoptosis of human gingival epithelial cells (hGECs) is one of the representative events of DM-associated periodontitis. Thus, this study aimed to investigate PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy activated in the process of high glucose (HG)-induced hGECs apoptosis.

METHODS

For dose-response studies, hGECs were incubated in different concentrations of glucose (5.5, 15, 25, and 50 mmol/L) for 48 h. Then, hGECs were challenged with 25 mmol/L glucose for 12 h and 48 h, respectively. Apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL), caspase 9 and mitochondrial membrane potential (MMP). Subsequently, autophagy was evaluated by estimating P62, LC3 II mRNA levels, LC3 fluorescent puncta and LC3-II/I ratio. Meanwhile, the involvement of PINK1-mediated mitophagy was assessed by qRT-PCR, western blotting and immunofluorescence. Finally, hGECs were transfected with shPINK1 and analyzed by MMP, caspase 9 and annexin V-FITC apoptosis.

RESULTS

The number of TUNEL-positive cells and caspase 9 protein were significantly increased in cells challenged with HG (25 mmol/L) for 48 h (HG 48 h). MMP was impaired both at HG 12 h and HG 48 h, but the degree of depolarization was more serious at HG 48 h. The autophagy improved as the amount of LC3 II increased and p62 decreased in HG 12 h. During this process, HG 12 h treatment induced PINK1-mediated mitophagy. PINK1 silencing with HG 12 h resulted in MMP depolarization and cell apoptosis.

CONCLUSIONS

These results suggested that loss of the PINK1 gene may cause mitochondrial dysfunction and increase sensitivity to HG-induced apoptosis of hGECs at the early stage. PINK1 mediated mitophagy attenuates early apoptosis of gingival epithelial cells induced by high glucose.

Integrated UPLC-MS and Network Pharmacology Approach to Explore the Active Components and the Potential Mechanism of Yiqi Huoxue Decoction for Treating Nephrotic Syndrome

Background: Yiqi Huoxue Decoction (YQHXD) is a traditional Chinese medicine that promotes blood circulation, removes blood stasis, facilitates diuresis, and alleviates edema. It is composed of 10 herbal medicines and has extensive application in treating nephrotic syndrome (NS). However, the active components and the potential mechanism of YQHXD for treating NS remain unclear.

Methods: We set up a sensitive and rapid method based on Ultra-High Performance Liquid Chromatograph-Mass (UPLC-MS) to identify the compounds in YQHXD and constituents absorbed into the blood. Disease genes were collected through GeneCards, DisGeNET, and OMIM database. Genes of compounds absorbed into blood were predicted by the TCMSP database. We constructed Disease-Drug-Ingredient-Gene (DDIG) network using Cytoscape, established a Protein-protein interaction (PPI) network using String, Gene biological process (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed using DAVID. Cellular experiments were performed to validate the results of network pharmacology.

Result: A total of 233 compounds in YQHXD and 50 constituents absorbed into the blood of rats were identified. The 36 core targets in the PPI network were clustered in the phosphatidylinositol 3 kinase-RAC serine/threonine-protein kinase (PI3K-AKT) and nuclear factor kappa-B (NF-κB) signaling pathways. Luteolin, Wogonin, Formononetin, and Calycosin were top-ranking components as potentially active compounds.

Conclusion: The results of our studies show that YQHXD is able to enhance renal function, alleviate podocyte injury, and improve adriamycin nephrotic syndrome.

MiR-142-3p ameliorates high glucose-induced renal tubular epithelial cell injury by targeting BOD1

BACKGROUND

Tubular injury plays a crucial role in the pathogenesis of diabetic nephropathy (DN). It is well known that many microRNAs (miRNAs) exert crucial effects on tubular injury. This study intends to explore the effect of miR-142-3p on the apoptosis and oxidative stress of high glucose (HG)-treated renal tubular epithelial cells (HK-2) and its underlying mechanism.

MATERIALS AND METHODS

HK-2 cells were exposed to HG to mimic cell injury. MTT assays and flow cytometry analyses were conducted to measure cell viability and cell apoptosis, respectively. RT-qPCR and western blot analyses were carried out to detect RNA and protein levels, respectively. The levels of oxidative stress markers were evaluated by ELISA. The binding between miR-142-3p and biorientation of chromosomes in cell division 1 (BOD1) was validated by a luciferase reporter assay.

RESULT

MiR-142-3p is low-expressed in HG-stimulated HK-2 cells. Functionally, miR-142-3p overexpression attenuates the apoptosis and oxidative stress of HG-stimulated HK-2 cells. Mechanistically, BOD1 was confirmed to be targeted by miR-142-3p in HK-2 cells. Moreover, BOD1 overexpression reversed the suppressive effect of miR-142-3p overexpression on the apoptosis and oxidative stress of HK-2 cells treated with HG.

CONCLUSION

MiR-142-3p ameliorates HG-induced renal tubular epithelial cell injury by targeting BOD1. The finding might provide novel insight into the role of miR-142-3p/BOD1 axis in DN treatment.

Galangin attenuates oxidative stress-mediated apoptosis in high glucose-induced renal tubular epithelial cells through modulating renin-angiotensin system and PI3K/AKT/mTOR pathway

This study was to evaluate the regulatory network among Galangin (Gal), oxidative stress, and renin-angiotensin system (RAS) in diabetic nephropathy (DN) in vitro. A cell model of DN was set up by exposing HK-2 cells to high glucose (HG, 30 mM) for 48 h and Gal was applied at 10 μM when needed. mRNA expression was analyzed by qPCR and protein level was detected by western blot. Malondialdehyde level and superoxide dismutase activity were evaluated by commercial kits. We analyzed cell viability by CCK8 assay and apoptosis by flow cytometry. DCFH-DA staining was conveyed for reactive oxygen species detection. HG induced RAS activation, oxidative stress, while inhibited cell viability. Gal suppressed oxidative stress-mediated apoptosis of HK-2 cells under the stimulation of HG via inhibiting RAS activation. Moreover, overexpression of AT1R, a RAS gene, could restrain the mitigative effect of Gal on cell injury. Furthermore, repression of RAS induced by AT1R knockdown partially reversed HG-induced PI3K/AKT/mTOR activation and oxidative stress in HK-2 cells. Also, AKT activation could antagonize Gal's functional roles in renal cell damage. Collectively, Gal alleviates HG-induced oxidative stress injury of renal tubular epithelial cells through PI3K/AKT/mTOR signal via modulating RAS activation. This finding would help to better understand mechanism of DN development and support future studies.

Update on the Mechanisms of Tubular Cell Injury in Diabetic Kidney Disease

Increasing evidence supports a role of proximal tubular (PT) injury in the progression of diabetic kidney disease (DKD), in patients with or without proteinuria. Research on the mechanisms of the PT injury in DKD could help us to identify potential new biomarkers and drug targets for DKD. A high glucose transport state and mismatched local hypoxia in the PT of diabetes patients may be the initiating factors causing PT injury. Other mechanism such as mitochondrial dysfunction, reactive oxygen species (ROS) overproduction, ER stress, and deficiency of autophagy interact with each other leading to more PT injury by forming a vicious circle. PT injury eventually leads to the development of tubulointerstitial inflammation and fibrosis in DKD. Many downstream signaling pathways have been demonstrated to mediate these diseased processes. This review focuses mostly on the novel mechanisms of proximal renal tubular injury in DKD and we believe such review could help us to better understand the pathogenesis of DKD and identify potential new therapies for this disease.

Salvianolic Acid B Protects Against Fatty Acid-Induced Renal Tubular Injury via Inhibition of Endoplasmic Reticulum Stress

Background/Aims: Obesity-related kidney disease is associated with elevated levels of saturated free fatty acids (SFA). SFA lipotoxicity in tubular cells contributes to significant cellular apoptosis and injury. Salvianolic acid B (SalB) is the most abundant bioactive molecule from Radix Salviae Miltiorrhizae. In this study, we investigated the effect of SalB on SFA-induced renal tubular injury and endoplasmic reticulum (ER) stress, in vivo and in vitro. Methods: C57BL/6 mice were assigned to five groups: a control group with normal diet (Nor), high-fat diet group (HFD), and HFD with three different SalB treatment doses, low (SalBL; 3 mg/kg), medium (SalBM; 6.25 mg/kg), and high (SalBH; 12.5 mg/kg) doses. SalB was intraperitoneally injected daily for 4 weeks after 8 weeks of HFD. After 12 weeks, mice were sacrificed and kidneys and sera were collected. Apoptosis and ER stress were induced in human proximal tubule epitelial (HK2) cells by palmitic acid (PA, 0.6 mM), tunicamycin (TM, 1 μg/ml), or thapsigargin (TG, 200 nM) in vitro. Results: C57BL/6 mice fed a high-fat diet (HFD) for 12 weeks exhibited increased apoptosis (Bax and cleaved caspase-3) and ER stress (BIP, P-eIF2α, ATF4, CHOP, ATF6, IRE1α, and XBP1s) markers expression in the kidney, compared with control mice, which were remarkably suppressed by SalB treatment. In vitro studies showed that PA (0.6 mM) induced apoptosis and ER stress in cultured HK2 cells. SalB treatment attenuated all the adverse effects of PA. However, SalB failed to inhibit TM or TG-induced ER stress in HK2 cells. Conclusion: The study indicated that SalB may play an important role in obesity-related kidney injury via mediating SFA-induced ER stress.

Activation of Akt-dependent Nrf2/ARE pathway by restoration of Brg-1 remits high glucose-induced oxidative stress and ECM accumulation in podocytes

Brahma-related gene 1 (Brg-1) is perceived as a cytoprotective protein due to its role in alleviating oxidative stress and apoptosis. Our study aimed to explore the role and mechanism of Brg-1 in high glucose (HG)-stimulated podocytes. The HG exposure downregulated Brg-1 and inactivated the protein kinase B (Akt) pathway in podocytes. Restoration of Brg-1 inhibited HG-induced viability reduction of podocytes. The HG-induced increase of reactive oxygen species and malondialdehyde levels and decrease of superoxide dismutase activity in podocytes were reversed by the Brg-1 overexpression. The Brg-1 overexpression terminated the HG-induced production of fibronectin, collagen IV, transforming growth factor-β1, and connective tissue growth factor. In addition, the Brg-1 overexpression activated Akt-dependent nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling in HG-stimulated podocytes. However, inhibition of the Akt pathway or Nrf2 silencing counteracted the protective effects of Brg-1 in HG-stimulated podocytes. In conclusion, the Brg-1 overexpression suppressed HG-induced oxidative stress and extracellular matrix accumulation by activation of Akt-dependent Nrf2/ARE signaling in podocytes.

Polysulfide-mediated sulfhydration of SIRT1 prevents diabetic nephropathy by suppressing phosphorylation and acetylation of p65 NF-κB and STAT3

Diabetic kidney disease is known as a major cause of chronic kidney disease and end stage renal disease. Polysulfides, a class of chemical agents with a chain of sulfur atoms, are found to confer renal protective effects in acute kidney injury. However, whether a polysulfide donor, sodium tetrasulfide (Na₂S₄), confers protective effects against diabetic nephropathy remains unclear. Our results showed that Na₂S₄ treatment ameliorated renal dysfunctional and histological damage in diabetic kidneys through inhibiting the overproduction of inflammation cytokine and reactive oxygen species (ROS), as well as attenuating renal fibrosis and renal cell apoptosis. Additionally, the upregulated phosphorylation and acetylation levels of p65 nuclear factor κB (p65 NF-κB) and signal transducer and activator of transcription 3 (STAT3) in diabetic nephropathy were abrogated by Na₂S₄ in a sirtuin-1 (SIRT1)-dependent manner. In renal tubular epithelial cells, Na₂S₄ directly sulfhydrated SIRT1 at two conserved CXXC domains (Cys371/374; Cys395/398), then induced dephosphorylation and deacetylation of its targeted proteins including p65 NF-κB and STAT3, thereby reducing high glucose (HG)-caused oxidative stress, cell apoptosis, inflammation response and epithelial-to-mesenchymal transition (EMT) progression. Most importantly, inactivation of SIRT1 by a specific inhibitor EX-527, small interfering RNA (siRNA), a de-sulfhydration reagent dithiothreitol (DTT), or mutation of Cys371/374 and Cys395/398 sites at SIRT1 abolished the protective effects of Na₂S₄ on diabetic kidney insulting. These results reveal that polysulfides may attenuate diabetic renal lesions via inactivation of p65 NF-κB and STAT3 phosphorylation/acetylation through sulfhydrating SIRT1.

Revealing active components, action targets and molecular mechanism of Gandi capsule for treating diabetic nephropathy based on network pharmacology strategy

Background

Gandi capsule is a traditional Chinese herbal formula used to promote blood circulation and removing blood stasis in clinical. Our previous study has shown that it reduces proteinuria with routine treatment in diabetic nephrophy (DN), but its pharmacological action mechanism is still unknown.

Methods

To facilitate the identification of components, a component database of Gandi capsule and target database of DN were established by ourselves. The components absorbed in blood circle were identified in rat plasma after oral administration of Gandi capsule by UHPLC-QQQ-MS/MS. The potential targets were screened by using Libdock tolls in Discovery studio 3.0. Then Pathway and Network analyses were used to enrich the screened targets. The possible targets were verified by using a surface plasmon resonance (SPR) test and the molecular mechanism focusing these targets for treating DN was clarified by western blot.

Results

Six components in Gandi capsule were identified detected in rat plasma after oral administration by UHPLC-QQQ-MS/MS. After molecular docking analyses in KEGG and Discovery studio, four protein targets including HNF4A, HMGCR, JAK3, and SIRT1, were screened out, and proved as effective binding with baicalin, wogonoside by SPR. And the molecular mechanism was clarified that baicalin and wogonoside inhibit the effect of high glucose (HG)-induced decreased cell viability and podocin expression, and strengthen the activation p-AKT, p-PI3K, and p-AMPK.

Conclusion

Baicalin and wogonoside were screened out to be the active compounds in Gandi capsule and can ameliorate HG-induced podocyte damage by influencing the AMPK and PI3K-AKT signaling pathways by binding with HNF4A, HMGCR, JAK3, and SIRT1.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-020-03155-4.

Astilbin combined with lipopolysaccharide induces IL-10-producing regulatory B cells via the STAT3 signalling pathway

OBJECTIVES

Astilbin exerts immunoregulatory activities and plays anti-inflammatory effects in inflammation-associated diseases. IL-10-producing B cells are the major subset of regulatory B cells (Bregs) and inhibit inflammation and autoimmune diseases. This study aimed to analyse the inducing effect of astilbin on Bregs and investigate the involved molecular mechanisms.

METHODS

The frequencies and activities of IL-10-producing Bregs were observed using the co-treatment of astilbin and lipopolysaccharide (LPS) ex vivo. The protective effect of astilbin/LPS-induced Bregs on dextran sulphate sodium (DSS)-induced colitis was confirmed in vivo. The molecular signalling events of Breg induction were checked via Western blot. CD40-/- and toll-like receptor (TLR) 4-/- B cells were treated with astilbin/LPS to determine the modulatory role of CD40 or TLR4 on astilbin/LPS-induced Bregs.

RESULTS

Although astilbin alone could not affect Bregs, the co-treatment of astilbin and LPS remarkably induced CD19+ CD1dhi and CD19+ TIM-1+ cells which produced IL-10 ex vivo. Colonic CD19+ CD1dhi and CD19+ TIM-1+ cells were also increased in astilbin-treated mice with DSS-induced colitis. The adoptive transfer of CD19+ TIM-1+ cells pre-induced by astilbin/LPS directly suppressed the progression of DSS-induced colitis. Combined astilbin and LPS stimulated the STAT3 activation of CD19+ TIM-1+ cells but had no effects on SOCS3, AKT, NF-κB, Erk, JNK nor P38. Inhibiting the STAT3 phosphorylation of CD19+ TIM-1+ cells abolished Breg induction by astilbin/LPS. Furthermore, Breg induction was weakened in CD40-/- B cells with the decrease in STAT3 activation, but had disappeared in TLR4-/- B cells with no STAT3 activation, thereby confirming the indispensable role of TLR4 signalling in the induction of IL-10-producing Bregs.

CONCLUSIONS

This study reports the new immunoregulatory role of astilbin for promoting IL-10-producing B cells and suggests the possible use of astilbin in the therapy of inflammatory diseases.

ASTILBIN: A PROMISING UNEXPLORED COMPOUND WITH MULTIDIMENSIONAL MEDICINAL AND HEALTH BENEFITS

BACKGROUND

Many flavonoids have various beneficial actions like anti-inflammatory, anti-carcinogenic properties and many other clinical conditions. Astilbin is one such flavanoid compound having many physiological as well as pharmacological actions.

PURPOSE

To summarize the important findings from the research conducted using astilbin having significance to its physiological and pharmacological activities as well as the patents filed using astilbin.

STUDY DESIGN

Systematic review and compilation of the collected literature.

METHOD

An extensive investigation of literature was done using several worldwide electronic scientific databases like PUBMED, SCOPUS, Science Direct and Google Scholar etc. All the article available in the English language that used our compound of interest i.e. astilbin, on the basis of inclusion criteria decided were retrieved from these databases, thoroughly reviewed and were summarized.

RESULT

It has been established that astilbin can play a vital in the management of diseases associated with immune system. It also possesses antibacterial, anti-oxidative and hepatoprotective activity.

CONCLUSION

These researches provide evidence that astilbin possesses great potential and thus can be utilized in the management of various disorders, thus establishing itself as a potential candidate for novel drug development. Also, there is still room for research on astilbin like it can be evaluated for anticancer potential, protective effect in various diabetic complications and many more. Overall observations from data suggested that astilbin is a promising compound and proved its efficacy in every preclinical study which is conducted till date. Some of the pharmacological activity is still unexplored. After successful preclinical trials, astilbin can go for further clinical trials.

Astilbin protects against cerebral ischaemia/reperfusion injury by inhibiting cellular apoptosis and ROS-NLRP3 inflammasome axis activation

BACKGROUND

Ischaemic stroke is a lethal cerebrovascular disease that occurs worldwide. Astilbin is a natural flavonoid compound with various physiological activities. The purpose of this study was to investigate the neuroprotective effects of Astilbin after cerebral ischaemia reperfusion (I/R) injury.

METHODS

The oxygen and glucose deprivation (OGD) model was used to simulate cerebral I/R injury in vitro. Cell viability was measured via CCK-8 and LDH release assays. Cell apoptosis was measured via Hoechst 33258 staining and flow cytometry assays. ROS was detected via flow cytometry assay. The protein expression levels were determined by western blotting. The middle cerebral artery occlusion (MCAO) model was used to simulate cerebral I/R injury in vivo. Cerebral ischaemic volume was measured by TTC staining. The Zea-Longa score, rota-rod test, and foot-fault test were used to evaluate behavioural changes and neurological deficits in rats.

RESULTS

Astilbin significantly enhanced cell viability and decreased LDH release after OGD treatment in vitro. Astilbin effectively curbed cell apoptosis induced by OGD via inhibiting the activation of caspase-3, decreasing the ratio of Bax/Bcl-2 and decreasing FADD. Astilbin also inhibited OGD-induced inflammation by suppressing ROS-NLRP3 inflammasome axis activation. Further results revealed that Astilbin could suppress the MAPK pathway and activate the PI3K/AKT pathway. Finally, Astilbin significantly reduced the cerebral infarction volume and relieved neurological deficits in rats in vivo.

CONCLUSION

Astilbin could defend against cerebral I/R injury by inhibiting apoptosis and inflammation via suppressing the MAPK pathway and activating the AKT pathway.

Pharmacokinetic, bioavailability and tissue distribution study of astilbin in rats

OBJECTIVE

The purpose of this study is to reveal the pharmacokinetic profiles of astilbin with various doses in rats and investigate the oral absolute bioavailability and tissue distribution of astilbin after oral administration.

METHODS

Wistar rats were orally administered astilbin 12, 24 mg/kg and intravenous administered astilbin 6 mg/kg randomly. The concentration of astilbin in rat plasma and various tissue samples was determined by LC-MS/MS method. Noncompartmental pharmacokinetic parameters including AUC and t_1/2 were calculated from plasma concentration-time data of astilbin with the DAS 3.0.

KEY FINDINGS

After oral administration of astilbin 12 and 24 mg/kg to rats, the oral absolute bioavailability of astilbin were 1.16 ± 0.695% and 1.27 ± 0.379%; the plasma elimination half-lives (t_1/2 ) were 101 ± 35.8 and 109 ± 25.3 min, respectively. Astilbin had a rapid absorption and a wide distribution throughout the whole body except liver and fat following oral administration. Astilbin could penetrate the blood-brain barrier of rat.

CONCLUSIONS

The oral absolute bioavailability of astilbin is poor because of the low permeability and solubility. Both oral absorption and clearance of astilbin in rats are rapid after oral administration.

Mechanisms of Herbal Nephroprotection in diabetes mellitus

Diabetic nephropathy (DN) is a leading cause of kidney morbidity. Despite the multilayered complexity of the mechanisms involved in the pathogenesis of DN, the conventional treatment is limited to just a few drug classes fraught with the risk of adverse events, including the progression of renal dysfunction. Phytoceuticals offer a promising alternative as they act on the many-sidedness of DN pathophysiology, multitargeting its intricacies. This paper offers a review of the mechanisms underlying the protective action of these phytoagents, including boosting the antioxidant capabilities, suppression of inflammation, averting the proliferative and sclerosing/fibrosing events. The pathogenesis of DN is viewed as a continuum going from the original offense, high glucose, through the noxious products it generates (advanced glycation end-products, products of oxidative and nitrosative stress) and the signaling chains consequently brought into action, to the harmful mediators of inflammation, sclerosis, and proliferation that eventually lead to DN, despite the countervailing attempts of the protective mechanisms. Special attention was given to the various pathways involved, pointing out the ability of the phytoagents to hinder the deleterious ones (especially those leading to, driven by, or associated with TGF-β activation, SREBP, Smad, MAPK, PKC, NF-κB, NLRP3 inflammasome, and caspase), to promote the protective ones (PPAR-α, PPAR-γ, EP4/Gs/AC/cAMP, Nrf2, AMPK, and SIRT1), and to favorably modulate those with potentially dual effect (PI3K/Akt). Many phytomedicines have emerged as potentially useful out of in vitro and in vivo studies, but the scarcity of human trials seriously undermines their usage in the current clinical practice-an issue that stringently needs to be addressed.

Critical roles of PI3K/Akt/NF‑κB survival axis in angiotensin II‑induced podocyte injury

Numerous studies have reported that angiotensin (Ang) II, nephrin, and podocin serve pivotal roles in podocyte injury, and thus can lead to the occurrence of proteinuria and the progression of kidney diseases. This study aimed to investigate the effects of Ang II on the production of nephrin and podocin, and their relationship with podocyte injury. We also aimed to determine whether nephrin, podocin and caspase-9 production depends on the PI3K/Akt/nuclear factor (NF)-κB signaling pathway in cultured mouse podocytes. We treated mouse podocytes with different doses of Ang II (10⁻⁹, 10⁻⁸, 10⁻⁷ and 10⁻⁶ mol/l) for 12, 24, and 48 h to analyse cell viability, and at 10⁻⁶ mol/l Ang II for 12, 24, and 48 h to evaluate cell apoptosis. Cells were treated with 10⁻⁶ mol/l of Ang II and/or LY294002 (inhibitor of Akt) or 740Y-P (activator of PI3K) for 48 h to detect Akt, phosphorylated (phospho)-Akt, p65 NF-κB, and phospho-p65 NF-κB, nephrin, podocin and caspase-9 expression, and podocyte apoptosis. Treatment with Ang II suppressed the viability and promoted the apoptosis of podocytes in a dose- and time-dependent manner. Ang II decreased phospho-Akt, phospho-p65 NF-κB, nephrin, and podocin and increased caspase-9 expression, while podocyte apoptosis was promoted. LY294002 further enhanced Ang II-induced downregulation of Akt and p65 NF-κB activation, as well as upregulation of caspase-9 mRNA and protein, and promoted the apoptosis of podocytes. Of note, 740Y-P restored Ang II-induced downregulation of Akt and p65 NF-κB activation, and upregulation of caspase-9, and decreased podocyte apoptosis. Interestingly, LY294002 and 740Y-P were determined to have no notable effects on the expression of nephrin and podocin. The data suggested that Ang II could regulate the expression of nephrin, podocin and caspase-9. Collectively, our findings suggested that the PI3K/Akt/NF-κB survival axis may serve a pivotal role in podocyte injury.

Resveratrol Protects Against Post-Contrast Acute Kidney Injury in Rabbits With Diabetic Nephropathy

Resveratrol (Res) is a multi-functional polyphenol compound that has protective functions in acute kidney diseases. Here, we examined whether the resveratrol could ameliorate post-contrast acute kidney injury (PC-AKI) following diabetic nephropathy (DN), and explored any underlying mechanism(s) in vivo and in vitro. Twenty-four rabbits with DN were randomly divided into four groups: control (Cont), resveratrol (Res), iohexol (PC-AKI), and resveratrol plus iohexol (Res+PC-AKI) groups. Functional magnetic resonance imaging, renal histology, blood and urinary biomarkers, silent information regulator l (SIRT1), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), hypoxia-inducible transcription factor-1α (HIF-1α), and apoptosis-associated protein expression were assessed ex vivo. For in vitro experiments, renal tubular epithelial (HK-2) cells subjected to high glucose conditions were treated with resveratrol, Ex527, an SIRT1 inhibitor, or 2-methoxyestradiol (2-MeOE2), HIF-1α inhibitor, before treatment with iohexol. With regard to the rabbit model of acute renal injury in DN, compared to the PC-AKI group, the Res+PC-AKI group showed decreased levels of cystatin C and urinary neutrophil gelatinase-associated lipocalin, increased pure molecular diffusion (D) and the fraction of water flowing in capillaries (f), a decreased apparent relaxation rate (R2*), renal injury score and apoptosis rate, increased protein expression levels of SIRT1 and PGC-1α, and decreased levels of HIF-1α and apoptosis-associated protein. In addition, iohexol decreased HK-2 cell survival and increased the cell apoptosis rate; results were reversed after treating cells with resveratrol. Resveratrol reduced renal hypoxia, mitochondrial dysfunction and renal tubular cell apoptosis by activating SIRT1-PGC-1α-HIF-1α signaling pathways in PC-AKI with DN.

Apigenin Protects Against Renal Tubular Epithelial Cell Injury and Oxidative Stress by High Glucose via Regulation of NF-E2-Related Factor 2 (Nrf2) Pathway

Background

Diabetic nephropathy (DN) is a disease characterized by oxidative stress and apoptosis of renal tubular epithelial cells driven by hyperglycemia. Apigenin is a flavonoid compound that possesses potent anti-apoptotic properties. The present study aimed to explore the protective effects and underlying mechanisms of apigenin on renal tubular epithelial cells exposed to hyperglycemia.

Material/Methods

Human renal epithelial cell HK-2 were incubated to D-glucose to establish in vitro DN model. The cell viability, lactate dehydrogenase (LDH) release, apoptosis and oxidative stress were evaluated. qRT-PCR was performed to determine the mRNA levels of NF-E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Western blot analysis was performed to measure the protein expressions of Nrf2.

Results

In HK-2 cells, high glucose reduced cell viability in a concentration- and time-dependent manner. Apigenin suppressed the decrease in cell viability and increase in supernatant LDH release at 100 and 200 μM after 48-h treatment. Apigenin reduced apoptotic rate and pro-inflammatory cytokines production. Apigenin suppressed oxidative stress and increased mRNA expressions of Nrf2 and HO-1. Inhibition of Nrf2 using small interfering RNA (siRNA), or cotreatment with LY294002, an inhibitor of PI3K/Akt, abolished the protective effect on high glucose-induced injury, oxidative stress, and pro-inflammatory cytokines production by apigenin. LY294002 also attenuated the increase in Nrf2 protein by apigenin in high glucose-treated HK-2 cells.

Conclusions

Apigenin protects renal tubular epithelial cells against high glucose-induced injury through suppression of oxidative stress and inflammation via activation of the Nrf2 pathway.

Canagliflozin reduces inflammation and fibrosis biomarkers: a potential mechanism of action for beneficial effects of SGLT2 inhibitors in diabetic kidney disease

AIMS/HYPOTHESIS

The sodium-glucose cotransporter 2 (SGLT2) inhibitor canagliflozin slows progression of kidney function decline in type 2 diabetes. The aim of this study was to assess the effect of the SGLT2 inhibitor canagliflozin on biomarkers for progression of diabetic kidney disease (DKD).

METHODS

A canagliflozin mechanism of action (MoA) network model was constructed based on an in vitro transcriptomics experiment in human proximal tubular cells and molecular features linked to SGLT2 inhibitors from scientific literature. This model was mapped onto an established DKD network model that describes molecular processes associated with DKD. Overlapping areas in both networks were subsequently used to select candidate biomarkers that change with canagliflozin therapy. These biomarkers were measured in 296 stored plasma samples from a previously reported 2 year clinical trial comparing canagliflozin with glimepiride.

RESULTS

Forty-four proteins present in the canagliflozin MoA molecular model overlapped with proteins in the DKD network model. These proteins were considered candidates for monitoring impact of canagliflozin on DKD pathophysiology. For ten of these proteins, scientific evidence was available suggesting that they are involved in DKD progression. Of these, compared with glimepiride, canagliflozin 300 mg/day decreased plasma levels of TNF receptor 1 (TNFR1; 9.2%; p < 0.001), IL-6 (26.6%; p = 0.010), matrix metalloproteinase 7 (MMP7; 24.9%; p = 0.011) and fibronectin 1 (FN1; 14.9%; p = 0.055) during 2 years of follow-up.

CONCLUSIONS/INTERPRETATION

The observed reduction in TNFR1, IL-6, MMP7 and FN1 suggests that canagliflozin contributes to reversing molecular processes related to inflammation, extracellular matrix turnover and fibrosis. Trial registration ClinicalTrials.gov NCT00968812.

PI3Kinases in Diabetes Mellitus and Its Related Complications

Recent studies have shown that phosphoinositide 3-kinases (PI3Ks) have become the target of many pharmacological treatments, both in clinical trials and in clinical practice. PI3Ks play an important role in glucose regulation, and this suggests their possible involvement in the onset of diabetes mellitus. In this review, we gather our knowledge regarding the effects of PI3K isoforms on glucose regulation in several organs and on the most clinically-relevant complications of diabetes mellitus, such as cardiomyopathy, vasculopathy, nephropathy, and neurological disease. For instance, PI3K α has been proven to be protective against diabetes-induced heart failure, while PI3K γ inhibition is protective against the disease onset. In vessels, PI3K γ can generate oxidative stress, while PI3K β inhibition is anti-thrombotic. Finally, we describe the role of PI3Ks in Alzheimer’s disease and ADHD, discussing the relevance for diabetic patients. Given the high prevalence of diabetes mellitus, the multiple effects here described should be taken into account for the development and validation of drugs acting on PI3Ks.

MiRNA-224-5p inhibits autophagy in breast cancer cells via targeting Smad4

BACKGROUND/AIMS

Autophagy is known as a protective intracellular procedure, which can be regulated by several factors. MiRNA has been suggested as a potential element to mediate autophagy pathway in carcinomas. Our study was aim to investigate the role of autophagy in breast cancer cells and identify the involved molecular mechanism METHODS: The expression of LC3I/II, SQSTM1 and Smad4 were detected by western blot. The mRNA level were quantified by real-time PCR. MDC staining was used to directly visualize autophagosome formation. Target Scan 7.2 was used to predict biological targets of miR-224-5p RESULTS: MiR-224 -5p expression was upregulated in metastatic breast cancer and non-metastatic breast cancer cells compare with control. Moreover, miR-224-5p inhibition enhanced cellular autophagy levels in breast cancer cells. MiR-224-5p could suppress Smad4 expression in MDA-MB-231 cells, which indicated that Smad4 was identified as a target of miR-224-5p in breast cancer cells with high metastatic potential CONCLUSIONS: Our study revealed that miR-224-5p inhibited autophagy by targeting Smad4 in MDA-MB-231 cells. The results indicated that miR-224-5p/Smad4 regulating autophagy might be a novel regulatory network contributing to metastasis of breast cancer. MiR-224-5p and Smad4 is involved in breast tumorigenesis, which is possibly a novel target for breast cancer therapy.

Astilbin Inhibits High Glucose-Induced Inflammation and Extracellular Matrix Accumulation by Suppressing the TLR4/MyD88/NF-κB Pathway in Rat Glomerular Mesangial Cells

Diabetic nephropathy (DN) is characterized by inflammatory responses and extracellular matrix (ECM) accumulation. Astilbin is an active natural compound and possesses anti-inflammatory activity. The aim of this study was to evaluate the anti-inflammatory effect of astilbin on high glucose (HG)-induced glomerular mesangial cells and the potential mechanisms. The results showed that HG induced cell proliferation of HBZY-1 cells in a time-dependent manner, and astilbin inhibited HG-induced cell proliferation. The expression and secretion of inflammatory cytokines, including interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), and ECM components, including collagen IV (Col IV) and fibronectin (FN), were induced by HG. Moreover, TGF-β1 and CTGF were also induced by HG. The induction by HG on inflammatory response and ECM accumulation was inhibited after astilbin treatment. Astilbin treatment also attenuated HG-induced decrease in expression of matrix metalloproteinase (MMP)-2 and MMP-9. The TLR4/MyD88/NF-κB pathway was activated by HG, and the inhibitor of TLR4 exhibited the same effect to astilbin on reversing the induction of HG. TLR4 overexpression attenuated the effect of astilbin on HG-induced inflammatory cytokine production and ECM accumulation. The results suggested that astilbin attenuated inflammation and ECM accumulation in HG-induced rat glomerular mesangial cells via inhibiting the TLR4/MyD88/NF-κB pathway. This work provided evidence that astilbin can be considered as a potential candidate for DN therapy.