Effect of Baoshenfang Formula on Podocyte Injury via Inhibiting the NOX-4/ROS/p38 Pathway in Diabetic Nephropathy

NLRP3 inflammasomes pathway: a key target for Metformin

Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing 3 (NLRP3) is a signaling pathway that is involved in inflammatory cascades, cell survival and the immune response. NLRP3 is activated by cellular damage, oxidative stress, and other factors that stimulate the immune system. Stimulation of NLRP3 induces inflammatory reactions and the production of inflammatory cytokines. These inflammatory mediators are implicated in several diseases. Metformin (MET) is an anti-hyperglycemia agent that is extensively used in clinical practice worldwide due to its high efficiency, safety profile, and affordable price. MET is the only member of biguanide class that is used in clinical practice and a potent AMP-activated protein kinase (AMPK) agonist with proven anti-inflammatory characteristics. Due to its anti-inflammatory properties, MET is considered to be effective against diseases that have an inflammatory background, and the NLRP3 pathway is involved in the pathophysiology of these disorders. In this review, we have evaluated the evidence if MET can affect this pathway and its utility for future therapeutic approaches.

Traditional Chinese Medicine Formulae and Chinese Patent Medicines for the Treatment of Diabetic Kidney Disease: Efficacies and Mechanisms

Diabetic kidney disease is one of the most significant comorbidities of diabetic patients, and has become the second cause of end-stage renal disease. Current clinical management programs have difficulty in reducing morbidity and poor prognosis, and thus new treatment options and concepts need to be developed. Traditional Chinese medicine formulae and Chinese patent medicines contain a variety of medicinal flavors, laying the material foundation for the multi-target, multi-level therapeutic features. This study describes the main pathologic features of DKD as well as its pathogenesis. Additionally, the categorization of TCM according to its different therapeutic mechanisms is discussed, and the signaling pathways targeted and corresponding biological effects are described in detail. For example, TCM formulae can alleviate oxidative stress through pathways such as Nrf2 and NOX4, can inhibit the development of inflammation through pathways such as TGF-β and NF-κB, and can ameliorate DKD by inhibiting endoplasmic reticulum stress and apoptosis. Moreover, it highlights the superior efficacy of the combined application of TCM formulae and Western medicine over Western medicine alone, which can compensate for the shortcomings of existing DKD treatment methods to a certain extent. TCM formulae and CPMs are promising candidates for the auxiliary treatment of DK, however, the lack of clarity regarding the active ingredients intensifies the difficulty of integrating TCM formulae and CPMs into clinical practice. Further research is warranted to explore the material basis and molecular mechanisms of action of TCM formulae against DKD.

Exploring the therapeutic mechanism of Yuebi decoction on nephrotic syndrome based on network pharmacology and experimental study

OBJECTIVE

This study aimed to explore the material basis of YBD and its possible mechanisms against NS through network pharmacology, molecular docking, and in vivo experiment.

METHODS

Active ingredients and potential targets of YBD were obtained through TCMSP and SwissTargetPrediction. NS-related targets were obtained from GeneCards, PharmGKB, and OMIM databases. The herb-ingredient-target network and PPI network were constructed by Cytoscape 3.9.1 and STRING database. GO and KEGG analyses were performed by DAVID database and ClueGO plugin. The connection between main active ingredients and core targets were revealed by molecular docking. To ascertain the effects and molecular mechanisms of YBD, a rat model was established by PAN.

RESULTS

We collected 124 active ingredients, 269 drug targets, and 2089 disease targets. 119 overlapping were screened for subsequent analysis. PPI showed that AKT1, STAT3, TRPC6, CASP3, JUN, PPP3CA, IL6, PTGS2, VEGFA, and NFATC3 were potential therapeutic targets of YBD against NS. Through GO and KEGG analyses, it showed the therapeutic effect of YBD on NS was closely involved in the regulation of pathways related to podocyte injury, including AGE-RAGE signaling pathway in diabetic complications and MAPK signaling pathway. Five key bioactive ingredients of YBD had the good affinity with the core targets. the experiment confirmed the renoprotective effects of YBD through reducing podocyte injury. Furthermore, YBD could downregulate expressions of PPP3CA, STAT3, NFATC3, TRPC6, and AKT1 in rats.

CONCLUSIONS

YBD might be a potential drug in the treatment of NS, and the underlying mechanism is closely associated with the inhibition of podocyte injury.

Podocyte Death in Diabetic Kidney Disease: Potential Molecular Mechanisms and Therapeutic Targets

Cell deaths maintain the normal function of tissues and organs. In pathological conditions, the abnormal activation or disruption of cell death often leads to pathophysiological effects. Diabetic kidney disease (DKD), a significant microvascular complication of diabetes, is linked to high mortality and morbidity rates, imposing a substantial burden on global healthcare systems and economies. Loss and detachment of podocytes are key pathological changes in the progression of DKD. This review explores the potential mechanisms of apoptosis, necrosis, autophagy, pyroptosis, ferroptosis, cuproptosis, and podoptosis in podocytes, focusing on how different cell death modes contribute to the progression of DKD. It recognizes the limitations of current research and presents the latest basic and clinical research studies targeting podocyte death pathways in DKD. Lastly, it focuses on the future of targeting podocyte cell death to treat DKD, with the intention of inspiring further research and the development of therapeutic strategies.

Efficacy and safety of traditional Chinese medicine decoction as an adjuvant treatment for diabetic nephropathy: a systematic review and meta-analysis of randomized controlled trials

Objective: This study aimed to assess the efficacy and safety of traditional Chinese medicine decoction as an adjunctive treatment for diabetic nephropathy in systematic evaluations. Methods: A comprehensive search was conducted in PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), and Wanfang databases, covering the period from January 2013 to July 2023. The search was restricted to randomized controlled trials (RCTs) conducted within the past decade that investigated the use of TCM decoction as an adjunctive treatment for diabetic nephropathy. The control group received western medicine treatment, while the intervention group received TCM decoction in addition to the conventional treatment. Endnote and Excel were employed for literature management and data organization, and Revman 5.3 and Stata 16 software were used for the analyses. Results: 66 RCTs involving 6,951 participants were included in this study. The clinical efficacy of TCM decoction as an adjunctive treatment for diabetic nephropathy was found to be significantly higher than that of the control group (OR = 3.12, 95% CI [2.70, 3.60], I2 = 0%, p < 0.00001). The incidence of adverse events did not differ significantly between the intervention group and the control group (OR = 0.94, 95% CI [0.60, 1.48], I2 = 0%, p = 0.94). According to the secondary outcomes of renal function and blood glucose indicators, the intervention group showed better therapeutic efficacy compared to the control group. The most frequently used TCM categories were tonifying medicine, blood-activating medicine, astringent medicine, diuretic medicine, heat-clearing medicine, and laxative medicine. Among them, the top five frequently used Chinese medicine were Astragalus mongholicus Bunge [Fabaceae; Astragali mongholici radix](58 times), Salvia miltiorrhiza Bunge [Lamiaceae; Radix et rhizoma salviae miltiorrhizae] (42 times), Dioscorea oppositifolia L. [Dioscoreaceae; Dioscoreae rhizoma] (38 times), Poria cocos (Schw.) Wolf [Polyporaceae; Poria] (38 times), and Cornus officinalis Siebold & Zucc. [Cornaceae; Corni fructus] (35 times). Conclusion: The combined use of TCM decoction with western medicine in the treatment of diabetic nephropathy can enhance clinical effectiveness and 2 This is a provisional file, not the final typeset article achieve superior therapeutic effects in comparison to western medicine alone, without significant risks. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier [CRD42022529144].

CD36-mediated podocyte lipotoxicity promotes foot process effacement

Background

Lipid metabolism disorders lead to lipotoxicity. The hyperlipidemia-induced early stage of renal injury mainly manifests as podocyte damage. CD36 mediates fatty acid uptake and the subsequent accumulation of toxic lipid metabolites, resulting in podocyte lipotoxicity.

Methods

Male Sprague-Dawley rats were divided into two groups: the normal control group and the high-fat diet group (HFD). Podocytes were cultured and treated with palmitic acid (PA) and sulfo-N-succinimidyl oleate (SSO). Protein expression was measured by immunofluorescence and western blot analysis. Boron-dipyrromethene staining and Oil Red O staining was used to analyze fatty acid accumulation.

Results

Podocyte foot process (FP) effacement and marked proteinuria occurred in the HFD group. CD36 protein expression was upregulated in the HFD group and in PA-treated podocytes. PA-treated podocytes showed increased fatty acid accumulation, reactive oxygen species (ROS) production, and actin cytoskeleton rearrangement. However, pretreatment with the CD36 inhibitor SSO decreased lipid accumulation and ROS production and alleviated actin cytoskeleton rearrangement in podocytes. The antioxidant N-acetylcysteine suppressed PA-induced podocyte FP effacement and ROS generation.

Conclusions

CD36 participated in fatty acid-induced FP effacement in podocytes via oxidative stress, and CD36 inhibitors may be helpful for early treatment of kidney injury.

The reporting quality of randomized controlled trials in Chinese herbal medicine (CHM) formulas for diabetes based on the consort statement and its extension for CHM formulas

Background: This study aimed to assess the overall reporting quality of randomized controlled trials (RCTs) in Chinese herbal medicine (CHM) formulas for patients with diabetes, and to identify factors associated with better reporting quality. Methods: Four databases including PubMed, Embase, Cochrane Library and Web of Science were systematically searched from their inception to December 2022. The reporting quality was assessed based on the Consolidated Standards of Reporting Trials (CONSORT) statement and its CHM formula extension. The overall CONSORT and its CHM formula extension scores were calculated and expressed as proportions separately. We also analyzed the pre-specified study characteristics and performed exploratory regressions to determine their associations with the reporting quality. Results: Seventy-two RCTs were included. Overall reporting quality (mean adherence) were 53.56% and 45.71% on the CONSORT statement and its CHM formula extension, respectively. The strongest associations with reporting quality based on the CONSORT statement were multiple centers and larger author numbers. Compliance with the CHM formula extension, particularly regarding the disclosure of the targeted traditional Chinese medicine (TCM) pattern (s), was generally insufficient. Conclusion: The reporting quality of RCTs in CHM formulas for diabetes remains unsatisfactory, and the adherence to the CHM formula extension is even poorer. In order to ensure transparent and standardized reporting of RCTs, it is essential to advocate for or even mandate adherence of the CONSORT statement and its CHM formula extension when reporting trials in CHM formulas for diabetes by both authors and editors.

Traditional Chinese medicine for the treatment of immune-related nephropathy: A review

Immune-related nephropathy (IRN) refers to immune-response-mediated glomerulonephritis and is the main cause of end-stage renal failure. The pathogenesis of IRN is not fully understood; therefore, treatment is challenging. Traditional Chinese medicines (TCMs) have potent clinical effects in the treatment of the IRN conditions immunoglobulin A nephropathy, lupus nephropathy, and diabetic nephropathy. The underlying mechanisms mainly include its inhibition of inflammation; improvements to renal interstitial fibrosis, oxidative stress, autophagy, apoptosis; and regulation of immunity. In this review, we summarize the clinical symptoms of the three IRN subtypes and the use of TCM prescriptions, herbs, and bioactive compounds in treating IRN, as well as the potential mechanisms, intending to provide a reference for the future study of TCM as IRN treatments.

COL4A3 Mutation Induced Podocyte Apoptosis by Dysregulation of NADPH Oxidase 4 and MMP-2

INTRODUCTION

Podocyte apoptosis is a common mechanism driving progression in Alport syndrome (AS). This study aimed to investigate the mechanism of podocyte apoptosis caused by COL4A3 mutations.

METHODS

We recruited patients with autosomal dominant AS (ADAS). Patients with minimal change disease (MCD) were recruited as controls. Microarray analysis was carried out on isolated glomeruli from the patients and validated. Then, corresponding mutant human podocytes (p.C1616Y) and 129 mice (p.C1615Y, the murine homolog to the human p.C1616Y) were constructed. The highest differentially expressed genes (DEGs) from microarray analysis were validated in transgenic mice and podocytes before and after administration of MMP-2 inhibitor (SB-3CT) and NOX4 inhibitor (GKT137831). We further validated NOX4/MMP-2/apoptosis pathway by real-time polymerase chain reaction (PCR), immunohistochemistry, and western blot in renal tissues from the ADAS patients.

RESULTS

Using microarray analysis, we observed that DEGs, including NOX4/H2O2, MMP-2, and podocyte apoptosis-related genes were significantly upregulated. These genes were validated by real-time PCR, histologic analysis, and western blot in corresponding mutant human podocyte (p.C1616Y) and/or mice models (p.C1615Y). Moreover, we found podocyte apoptosis was abrogated and MMP-2 expression was down-regulated both in vivo and in vitro by NOX4 inhibition, urinary albumin-to-creatinine ratio, 24-hour proteinuria; and renal pathologic lesion was attenuated by NOX4 inhibition in vivo. Furthermore, podocyte apoptosis was attenuated whereas NOX4 expression remained the same by inhibition of MMP-2 both in vivo and in vitro.

CONCLUSION

These results indicated that NOX4 might induce podocyte apoptosis through the regulation of MMP-2 in patients with COL4A3 mutations. Our findings provided new insights into the mechanism of ADAS.

Nox4 as a novel therapeutic target for diabetic vascular complications

Diabetic vascular complications can affect both microvascular and macrovascular. Diabetic microvascular complications, such as diabetic nephropathy, diabetic retinopathy, diabetic neuropathy, and diabetic cardiomyopathy, are believed to be caused by oxidative stress. The Nox family of NADPH oxidases is a significant source of reactive oxygen species and plays a crucial role in regulating redox signaling, particularly in response to high glucose and diabetes mellitus. This review aims to provide an overview of the current knowledge about the role of Nox4 and its regulatory mechanisms in diabetic microangiopathies. Especially, the latest novel advances in the upregulation of Nox4 that aggravate various cell types within diabetic kidney disease will be highlighted. Interestingly, this review also presents the mechanisms by which Nox4 regulates diabetic microangiopathy from novel perspectives such as epigenetics. Besides, we emphasize Nox4 as a therapeutic target for treating microvascular complications of diabetes and summarize drugs, inhibitors, and dietary components targeting Nox4 as important therapeutic measures in preventing and treating diabetic microangiopathy. Additionally, this review also sums up the evidence related to Nox4 and diabetic macroangiopathy.

Therapeutic effect and mechanism of combination therapy with ursolic acid and insulin on diabetic nephropathy in a type I diabetic rat model

This work aims to investigate the therapeutic effect of ursolic acid (UA) plus insulin (In) on diabetic nephropathy (DN) in streptozotocin (STZ)-induced T1DM rats. The experimental groups and operational details are as follows: A total of thirty-two SD rats were divided into four groups: the DN model group (DN, n = 8), DN + In treatment group (DN + In, n = 8), DN + In + UA administration group (DN + In + UA, n = 8), and negative control group (control, n = 8). After 8 weeks, changes in renal function indices and pathological damage were assessed. Additionally, oxidative stress-, apoptosis-, and fibrosis-related proteins in kidney tissue were measured. Compared with the control group, the vehicle group showed higher levels of creatine, blood urea nitrogen, urinary protein, apoptosis, and lipid peroxidation; lower superoxide dismutase levels; more severe levels of pathological kidney damage and renal fibrosis; and a deepened degree of EMT and EndMT. Better outcomes were achieved with the combined treatment than with insulin-only treatment. The improvement of TGF-β1, phosphorylated p38 MAPK, FGFR1, SIRT3 and DPP-4 expression levels in renal tissues after combination therapy was greater than that after insulin-only treatment. This study shows that the combination of insulin and UA significantly improved the pathological changes in the renal tissue of T1DM rats, and the underlying mechanism may be related to improving apoptosis and oxidative stress by regulating p38 MAPK, SIRT3, DPP-4 and FGFR1 levels, thereby blocking TGF-β signaling pathway activation and inhibiting EMT and EndMT processes.

tBHQ attenuates podocyte injury in diabetic nephropathy by inhibiting NADPH oxidase-derived ROS generation via the Nrf2/HO-1 signalling pathway

Aims

Oxidative stress plays a crucial role in podocyte injury in diabetic nephropathy (DN). tert-Butylhydroquinone (tBHQ) is an activator of Nrf2 that exerts protective effects in diabetic mice, but the underlying mechanism of tBHQ in the podocytes of DN is not fully understood.

Materials and methods

A high glucose (HG)-induced HK2 cell model and streptozotocin-induced rat model of DN were established and treated with tBHQ or apocynin. The expression levels of Nrf2, HO-1, NOX2 and NOX4 were determined by Western blot or immunohistochemical staining. The level of oxidative stress in podocytes or kidney tissues was assessed using DCFH-DA or dihydroethidium (DHE) staining. Cell injury was assessed by F-actin staining and flow cytometry analysis.

Key findings

We showed that HG treatment increased the expressions of NOX2 and NOX4 and enhanced ROS production in podocytes. Inhibition of NADPH oxidase activity by apocynin dramatically attenuated HG-induced ROS production and further alleviated cell injury and apoptosis in podocytes. Moreover, we found that HG inhibited the Nrf2/HO-1 signalling pathway in podocytes; however, tBHQ treatment significantly activated the Nrf2 signalling pathway, inhibited NADPH oxidase activity, and attenuated ROS production and cell injury in HG-treated podocytes. Furthermore, we observed that tBHQ treatment partially attenuated renal injury, activated the Nrf2 signalling pathway, inhibited NADPH oxidase activity and reduced ROS generation in the kidneys of STZ-induced diabetic rats.

Significance

These results suggest that tBHQ exerts a protective role in hyperglycaemia-induced podocyte injury, and that the potential protective mechanism of tBHQ involves inhibiting NADPH oxidase-derived ROS generation by activating the Nrf2/HO-1 signalling pathway.

Mitochondrial Oxidative Stress and Cell Death in Podocytopathies

Podocytopathies are kidney diseases that are driven by podocyte injury with proteinuria and proteinuria-related symptoms as the main clinical presentations. Albeit podocytopathies are the major contributors to end-stage kidney disease, the underlying molecular mechanisms of podocyte injury remain to be elucidated. Mitochondrial oxidative stress is associated with kidney diseases, and increasing evidence suggests that oxidative stress plays a vital role in the pathogenesis of podocytopathies. Accumulating evidence has placed mitochondrial oxidative stress in the focus of cell death research. Excessive generated reactive oxygen species over antioxidant defense under pathological conditions lead to oxidative damage to cellular components and regulate cell death in the podocyte. Conversely, exogenous antioxidants can protect podocyte from cell death. This review provides an overview of the role of mitochondrial oxidative stress in podocytopathies and discusses its role in the cell death of the podocyte, aiming to identify the novel targets to improve the treatment of patients with podocytopathies.

Recent Advances in Traditional Chinese Medicine for Treatment of Podocyte Injury

Podocyte is also called glomerular epithelial cell, which has been considered as the final gatekeeper of glomerular filtration barrier (GFB). As a major contributor to proteinuria, podocyte injury underlies a variety of glomerular diseases and becomes the challenge to patients and their families in general. At present, the therapeutic methods of podocyte injury mainly include angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, steroid and immunosuppressive medications. Nevertheless, the higher cost and side effects seriously disturb patients with podocyte injury. Promisingly, traditional Chinese medicine (TCM) has received an increasing amount of attention from different countries in the treatment of podocyte injury by invigorating spleen and kidney, clearing heat and eliminating dampness, as well enriching qi and activating blood. Therefore, we searched articles published in peer-reviewed English-language journals through Google Scholar, PubMed, Web of Science, and Science Direct. The protective effects of active ingredients, herbs, compound prescriptions, acupuncture and moxibustion for treatment of podocyte injury were further summarized and analyzed. Meanwhile, we discussed feasible directions for future development, and analyzed existing deficiencies and shortcomings of TCM in the treatment of podocyte injury. In conclusion, this paper shows that TCM treatments can serve as promising auxiliary therapeutic methods for the treatment of podocyte injury.

Antioxidant Roles of SGLT2 Inhibitors in the Kidney

The reduction-oxidation (redox) system consists of the coupling and coordination of various electron gradients that are generated thanks to serial reduction-oxidation enzymatic reactions. These reactions happen in every cell and produce radical oxidants that can be mainly classified into reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS modulate cell-signaling pathways and cellular processes fundamental to normal cell function. However, overproduction of oxidative species can lead to oxidative stress (OS) that is pathological. Oxidative stress is a main contributor to diabetic kidney disease (DKD) onset. In the kidney, the proximal tubular cells require a high energy supply to reabsorb proteins, metabolites, ions, and water. In a diabetic milieu, glucose-induced toxicity promotes oxidative stress and mitochondrial dysfunction, impairing tubular function. Increased glucose level in urine and ROS enhance the activity of sodium/glucose co-transporter type 2 (SGLT2), which in turn exacerbates OS. SGLT2 inhibitors have demonstrated clear cardiovascular benefits in DKD which may be in part ascribed to the generation of a beneficial equilibrium between oxidant and antioxidant mechanisms.

Suppressive effect erythropoietin on oxidative stress by targeting AMPK/Nox4/ROS pathway in renal ischemia reperfusion injury

OBJECTIVE

To explore the effect of erythropoietin (EPO) on the AMP-activated protein kinase (AMPK)/nicotinamide adenine dinucleotide phosphatase oxidase 4 (NOX4) signaling pathway during renal ischemia reperfusion injury (RIRI) in rats.

METHODS

A rat model of RIRI was established by clamping the left renal pedicle and removing the right kidney. The rats in the sham group did not have their left renal pedicle clamped. Rats with a model of RIRI were randomly divided into RIRI alone (control), erythropoietin treatment (EPO/RIRI), and Compound C treatment (CPC/RIRI) groups. Hematoxylin-eosin (H&E) staining was used to examine pathological kidney damage. Serum creatinine and urea nitrogen levels were measured to evaluate renal function. Western blotting was performed to detect the expression levels of phosphorylated p-AMPK and total AMPK protein in the kidneys. RT-PCR was used to evaluate the mRNA levels of Nox4 and p22 in the kidneys. Oxidative stress-related indices (ROS, CAT, GSH, SOD, and MDA) were also measured.

RESULTS

EPO treatment improved kidney function by preventing kidney damage induced by the RIRI model. Preventing ischemia/reperfusion injury in the RIRI model was correlated with an increased p-AMPK/AMPK ratio and elevated activity of CAT, GSH, and SOD, which ameliorated the expression of NOX4, p22, ROS, and MDA. Moreover, treatment with CPC (an AMPK inhibitor) reduced the effects of EPO in the RIRI model.

CONCLUSION

EPO treatment protected rats against RIRI in the RIRI model by alleviating oxidative stress by triggering the AMPK/NOX4/ROS pathway.

Mechanistic insights into the role of serum-glucocorticoid kinase 1 in diabetic nephropathy: A systematic review

Aberrant expression of serum-glucocorticoid kinase 1 (SGK1) contributes to the pathogenesis of multiple disorders, including diabetes, hypertension, obesity, fibrosis, and metabolic syndrome. SGK1 variant is expressed in the presence of insulin and several growth factors, eventually modulating various ion channels, carrier proteins, and transcription factors. SGK1 also regulates the enzymatic activity of Na⁺ K⁺ ATPase, glycogen synthase kinase-3, ubiquitin ligase Nedd4-2, and phosphomannose mutase impacting cell cycle regulation, neuroexcitation, and apoptosis. Ample evidence supports the crucial role of aberrant SGK1 expression in hyperglycemia-mediated secondary organ damage. Diabetic nephropathy (DN), a dreadful microvascular complication of diabetes, is the leading cause of end-stage renal failures with high morbidity and mortality rate. The complex pathogenesis of DN encompasses several influencing factors, including transcriptional factors, inflammatory markers, cytokines, epigenetic modulators, and abnormal enzymatic activities. SGK1 plays a pivotal role by controlling various physiological functions associated with the occurrence and progression of DN; therefore, targeting SGK1 may favorably influence the clinical outcome in patients with DN. This review aimed to provide mechanistic insights into SGK1 regulated DN pathogenesis and summarize the evidence supporting the therapeutic potential of SGK1 inhibition and its consequences on human health.

Huangkui capsule in combination with metformin ameliorates diabetic nephropathy via the Klotho/TGF-β1/p38MAPK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Huangkui capsule (HKC), extracted from Abelmoschus manihot (L.) medic (AM), as a patent proprietary Chinese medicine on the market for approximately 20 years, has been clinically used to treat chronic glomerulonephritis. Renal fibrosis has been implicated in the onset and development of diabetic nephropathy (DN). However, the potential application of HKC for preventing DN has not been evaluated.

AIM OF THE STUDY

This study was designed to investigate the efficacy and underlying mechanisms of HKC combined with metformin (MET), the first-line medication for treating type 2 diabetes, in the treatment of renal interstitial fibrosis.

MATERIALS AND METHODS

A rat model of diabetes-associated renal fibrosis was established by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg) combined with a high-fat and high-glucose diet. The rats were randomly divided into five groups: normal control, DN, HKC (1.0 g/kg/day), MET (100 mg/kg/d), and HKC plus MET (1.0 g/kg/day + 100 mg/kg/d). Following drug administration for 8 weeks, we collected blood, urine, and kidney tissue for analysis. Biochemical markers and metabolic parameters were detected using commercial kits. Histopathological staining was performed to monitor morphological changes in the rat kidney. High-glucose-induced human kidney HK-2 cells were used to evaluate the renal protective effects of HKC combined with MET (100 μg/mL+10 mmol/L). MTT assay and acridine orange/ethidium bromide were used to examine cell proliferation inhibition rates and apoptosis. Immunofluorescence assay and Western blot analysis were performed to detect renal fibrosis-related proteins including Klotho, TGF-β1, and phosphorylated (p)-p38.

RESULTS

Combination therapy (HKC plus MET) significantly improved the weight, reduced blood glucose (BG), blood urea nitrogen (BUN), total cholesterol (T-CHO), triglycerides (TG), low-density lipoprotein (LDL) and increased the level of high-density lipoprotein (HDL) of DN rats. Combination therapy also significantly reduced urine serum creatinine (SCR) and urine protein (UP) levels as well as reduced the degrees of renal tubule damage and glomerulopathy in DN rats. Combination therapy ameliorated renal fibrosis, as evidenced by reduced levels of alpha-smooth muscle actin and fibronectin and increased expression of E-cadherin in the kidneys. Moreover, HKC plus MET alleviated the degree of DN in part via the Klotho/TGF-β1/p38MAPK signaling pathway. In vitro experiments showed that combination therapy significantly inhibited cell proliferation and apoptosis and regulated fibrosis-related proteins in high-glucose (HG)-induced HK-2 cells. Further studies revealed that combination therapy suppressed cell proliferation and fibrosis by inhibiting the Klotho-dependent TGF-β1/p38MAPK pathway.

CONCLUSIONS

HKC plus MET in combination suppressed abnormal renal cell proliferation and fibrosis by inhibiting the Klotho-dependent TGF-β1/p38MAPK pathway. Collectively, HKC combined with MET effectively improved DN by inhibiting renal fibrosis-associated proteins and blocking the Klotho/TGF-β1/p38MAPK signaling pathway. These findings improve the understanding of the pathogenesis of diabetes-associated complications and support that HKC plus MET combination therapy is a promising strategy for preventing DN.

Clinical efficacies, underlying mechanisms and molecular targets of Chinese medicines for diabetic nephropathy treatment and management

Diabetic nephropathy (DN) has been recognized as a severe complication of diabetes mellitus and a dominant pathogeny of end-stage kidney disease, which causes serious health problems and great financial burden to human society worldwide. Conventional strategies, such as renin-angiotensin-aldosterone system blockade, blood glucose level control, and bodyweight reduction, may not achieve satisfactory outcomes in many clinical practices for DN management. Notably, due to the multi-target function, Chinese medicine possesses promising clinical benefits as primary or alternative therapies for DN treatment. Increasing studies have emphasized identifying bioactive compounds and molecular mechanisms of reno-protective effects of Chinese medicines. Signaling pathways involved in glucose/lipid metabolism regulation, antioxidation, anti-inflammation, anti-fibrosis, and podocyte protection have been identified as crucial mechanisms of action. Herein, we summarize the clinical efficacies of Chinese medicines and their bioactive components in treating and managing DN after reviewing the results demonstrated in clinical trials, systematic reviews, and meta-analyses, with a thorough discussion on the relative underlying mechanisms and molecular targets reported in animal and cellular experiments. We aim to provide comprehensive insights into the protective effects of Chinese medicines against DN.

Mefunidone ameliorates diabetic kidney disease in STZ and db/db mice

Diabetic kidney disease (DKD) is a major cause of end stage renal diseases worldwide. Despite successive interventions for delaying the progression of DKD, current treatments cannot reverse the pathological progression. Mefunidone (MFD) is a new compound with potent antifibrotic properties, but the effect of MFD on DKD remains unknown. Therefore, we investigated the protective effects of MFD in both models of the db/db type 2 diabetes (T2D) and streptozotocin (STZ)-induced type 1 diabetes (T1D) models. Compared with the model group, MFD treatment significantly reduced pathological changes observed by PAS staining, PASM staining, and Masson staining in vivo. To further elucidate the potential mechanisms, we discovered MFD treatment notably restored podocyte function, alleviated inflammation, abated ROS generation, inhibited the TGF-β1/SAMD2/3 pathway, suppressed the phosphorylation levels of MAPKs (ERK1/2, JNK, and P38), and reduced epithelial-to-mesenchymal transition(EMT). In conclusion, these findings demonstrate the effectiveness of MFD in diabetic nephropathy and elucidate its possible mechanism.

Pharmacological management of vascular endothelial dysfunction in diabetes: TCM and western medicine compared based on biomarkers and biochemical parameters

Diabetes, a worldwide health concern while burdening significant populace of countries with time due to a hefty increase in both incidence and prevalence rates. Hyperglycemia has been buttressed both in clinical and experimental studies to modulate widespread molecular actions that effect macro and microvascular dysfunctions. Endothelial dysfunction, activation, inflammation, and endothelial barrier leakage are key factors contributing to vascular complications in diabetes, plus the development of diabetes-induced cardiovascular diseases. The recent increase in molecular, transcriptional, and clinical studies has brought a new scope to the understanding of molecular mechanisms and the therapeutic targets for endothelial dysfunction in diabetes. In this review, an attempt made to discuss up to date critical and emerging molecular signaling pathways involved in the pathophysiology of endothelial dysfunction and viable pharmacological management targets. Importantly, we exploit some Traditional Chinese Medicines (TCM)/TCM isolated bioactive compounds modulating effects on endothelial dysfunction in diabetes. Finally, clinical studies data on biomarkers and biochemical parameters involved in the assessment of the efficacy of treatment in vascular endothelial dysfunction in diabetes was compared between clinically used western hypoglycemic drugs and TCM formulas.

Dopamine 1 receptor activation protects mouse diabetic podocytes injury via regulating the PKA/NOX-5/p38 MAPK axis

Diabetic nephropathy (DN) is a major microvascular complication of diabetes that can lead to end-stage renal disease. Podocytes constitute the last barrier of glomerular filtration, whose damage are the direct cause of proteinuria. Dopamine receptors are involved in the regulation of diabetes-induced glomerular hyperfiltration, and only dopamine 1 receptor (D1R) can be amplified in cultured mouse podocytes. However, the exact effect of D1R on diabetic podocytes remains unclear. This study aims to investigate the protective role of D1R activation on diabetic podocytes injury in vivo and vitro as well as its potential mechanism. We observed D1R protective effect respectively in streptozotocin (STZ)-induced type 1 diabetes (T1D) mice as well as mouse podocytes (MPC5) cultured in high glucose (HG, 40 mM) medium. It showed that D1R and podocyte-associated proteins (Podocin, CD2AP and Nephrin) expression were significantly decreased both in the T1D mice (fed for 8 and 12 weeks) and HG-cultured MPC5 cells, while the NOX-5 expression increased. In T1D mice, the levels of 24-h urine protein, serum creatinine and urinary 8-OHdG were increased in a time-dependent manner, at the same time, hematoxylin-eosin (HE) staining and electron microscope observed the kidney lesion and podocytes injury. In vitro, HG induced podocytes oxidative stress and apoptosis, which could be inhibited by SKF38393 (a D1R agonist) and N-acetyl-l-cysteine (NAC, a reactive oxygen species scavenger). Furthermore, there was a decreasing Podocin expression and a significant increasing NOX-5 expression in podocytes transfected with D1R-small interfering RNA (siRNA). More importantly, the expression of phospho-CREB (the PKA downstream transcription factor) was decreased and phospho-p38 MAPK was increased in HG-induced podocytes, which can respectively be activated or blocked by SKF38393, 8-Bromo-CAMP (a PKA activator), NAC, and SB20380 (a p38 MAPK inhibitor). In conclusion, D1R activation can protect diabetic podocytes from apoptosis and oxidative damage, in part through the PKA/NOX-5/p38 MAPK pathway.

A new research hot spot: The role of NLRP3 inflammasome activation, a key step in pyroptosis, in diabetes and diabetic complications

Pyroptosis is a form of cell death mediated by gasdermin D (GSDMD); it is characterised by NLRP3 inflammasome activation, caspase activation, cell membrane pore formation, and the release of interleukin-1β and interleukin-18. NLRP3 inflammasome activation plays a central role in pyroptosis. Recent research has suggested that NLRP3 inflammasome activation may be involved in the occurrence and development of diabetes mellitus and its associated complications. This finding provided the impetus for us to clarify the significance of pyroptosis in diabetes. In this review, we summarise the current understanding of the molecular mechanisms involved in pyroptosis, as well as recent advances in the role of NLRP3 inflammasome activation and pyroptosis in the development of diabetes and diabetic complications.

Effects of BSF on Podocyte Apoptosis via Regulating the ROS-Mediated PI3K/AKT Pathway in DN

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD). The ROS-mediated PI3K/AKT pathway plays a key role in podocyte apoptosis and DN progression. Our previous study demonstrated that Baoshenfang (BSF) can decrease proteinuria and attenuate podocyte injury. However, the effects of BSF on podocyte apoptosis induced by the ROS-mediated PI3K/AKT pathway remain unclear. Herein, in vivo and in vitro studies have been performed. In our in vivo study, BSF significantly decreased 24-h urinary protein, serum creatinine, and blood urea nitrogen levels in DN mice. Meanwhile, BSF significantly inhibited oxidative stress and podocyte apoptosis in our in vivo and in vitro studies. Moreover, BSF significantly decreased the inhibition of the PI3K/AKT pathway induced by HG in DN. More importantly, the effects of BSF on podocyte apoptosis were reversed by PI3K siRNA transfection. In conclusion, BSF can decrease proteinuria and podocyte apoptosis in DN, in part through regulating the ROS-mediated PI3K/AKT pathway.