Sodium butyrate ameliorated diabetic nephropathy-associated tubulointerstitial inflammation by modulating the tight junctions of renal tubular epithelial cells.

As one of the most significant pathological changes of diabetic nephropathy (DN), tubulointerstitial fibrosis (TIF) had a close relationship with tubulointerstitial inflammation (TI), and the occurrence of TI could have resulted from the disrupted tight junctions (TJs) of renal tubular epithelial cells (RTECs). Studies have demonstrated that sodium butyrate (NaB), a typical short chain fatty acid (SCFA), played an important regulatory role in intestinal TJs and inflammation. In this study, our in vivo and in vitro results showed that accompanied by TI, renal tubular TJs were gradually disrupted in the process of DN-related TIF. In HG and LPS co-cultured HK-2 cells and db/db mice, NaB treatment regained the TJs of RTECs via the sphingosine 1-phosphate receptor-1 (S1PR1)/AMPK signaling pathway, relieving inflammation. Small interfering RNA of S1PR1, S1PR1 antagonist W146 and agonist SEW2871, and AMPK agonist AICAR were all used to further confirm the essential role of the S1PR1/AMPK signaling pathway in NaB's TJ protection in RTECs in vitro. Finally, NaB administration not only improved the renal function and TIF, but also relieved the TI of db/db mice. These findings suggested that the use of NaB might be a potential adjuvant treatment strategy for DN-associated TIF, and this protective effect was linked to the TJ modulation of RTECs via the S1PR1/AMPK signaling pathway, leading to the improvement of TI.

Notoginsenoside Fc, a novel renoprotective agent, ameliorates glomerular endothelial cells pyroptosis and mitochondrial dysfunction in diabetic nephropathy through regulating HMGCS2 pathway.

BACKGROUND: Diabetic nephropathy (DN) is the primary cause of end-stage renal disease (ESRD), and the therapeutic strategies for DN are limited. Notoginsenoside Fc (Fc), a novel saponin isolated from Panax Notoginseng (PNG), has been reported to alleviate vascular injury in diabetic rats. However, the protective effects of Fc on DN remain unclear. PURPOSE: To investigate the beneficial effects and mechanisms of Fc on DN. METHODS: Db/db mice were treated with 2.5, 5 and 10 mg·kg-1·d-1 of Fc for 8 weeks. High glucose (HG) induced mouse glomerular endothelial cells (GECs) were treated with 2.5, 5 and 10 µM of Fc for 24 h. RESULTS: Our data found that Fc ameliorated urinary microalbumin level, kidney dysfunction and histopathological damage in diabetic mice. Moreover, Fc alleviated the accumulation of oxidative stress, the collapse of mitochondrial membrane potential and the expression of mitochondrial fission proteins, such as Drp-1 and Fis1, while increased the expression of mitochondrial fusion protein Mfn2. Fc also decreased pyroptosis-related proteins levels, such as TXNIP, NLRP3, cleaved caspase-1, and GSDMD-NT, indicating that Fc ameliorated GECs pyroptosis. In addition, 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) expression was increased in diabetic group, which was partially abrogated by Fc. Our data further proved that knockdown of HMGCS2 could restrain HG-induced GECs mitochondrial dysfunction and pyroptosis. These results indicated that the inhibitory effects of Fc on mitochondrial damage and pyroptosis were associated with the suppression of HMGCS2. CONCLUSION: Taken together, this study clearly demonstrated that Fc ameliorated GECs pyroptosis and mitochondrial dysfunction partly through regulating HMGCS2 pathway, which might provide a novel drug candidate for DN.

Effect and pharmacological mechanism of Salvia miltiorrhiza and its characteristic extracts on diabetic nephropathy.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetic nephropathy (DN) is a severe diabetic microvascular complication with an increasing prevalence rate and lack of effective treatment. Traditional Chinese medicine has been proven to have favorable efficacy on DN, especially Salvia miltiorrhiza Bunge (SM), one of the most critical and conventional herbs in the treatment. Over the past decades, studies have demonstrated that SM is a potential treatment for DN, and the exploration of the underlying mechanism has also received much attention. AIM OF THIS REVIEW: This review aims to systematically study the efficacy and pharmacological mechanism of SM in the treatment of DN to understand its therapeutic potential more comprehensively. MATERIALS AND METHODS: Relevant information was sourced from Google Scholar, PubMed, Web of Science, and CNKI databases. RESULTS: Several clinical trials and systematic reviews have indicated that SM has definite benefits on the kidneys of diabetic patients. And many laboratory studies have further revealed that SM and its characteristic extracts, mainly including salvianolic acids and tanshinones, can exhibit pharmacological activity against DN by the regulation of metabolism, renal hemodynamic, oxidative stress, inflammation, fibrosis, autophagy, et cetera, and several involved signaling pathways, thereby preventing various renal cells from abnormal changes in DN, including endothelial cells, podocytes, epithelial cells, and mesangial cells. CONCLUSION: As a potential drug for the treatment of DN, SM has multi-component, multi-target, and multi-pathway pharmacological effects. This work will not only verify the satisfactory curative effect of SM in the treatment of DN but also provide helpful insights for the development of new anti-DN drugs and the application of traditional Chinese medicine.

Canagliflozin regulates metabolic reprogramming in diabetic kidney disease by inducing fasting-like and aestivation-like metabolic patterns.

AIMS/HYPOTHESIS: Sodium-glucose co-transporter 2 (SGLT2) inhibitors (SGLT2i) are antihyperglycaemic drugs that protect the kidneys of individuals with type 2 diabetes mellitus. However, the underlying mechanisms mediating the renal benefits of SGLT2i are not fully understood. Considering the fuel switches that occur during therapeutic SGLT2 inhibition, we hypothesised that SGLT2i induce fasting-like and aestivation-like metabolic patterns, both of which contribute to the regulation of metabolic reprogramming in diabetic kidney disease (DKD). METHODS: Untargeted and targeted metabolomics assays were performed on plasma samples from participants with type 2 diabetes and kidney disease (n=35, 11 women) receiving canagliflozin (CANA) 100 mg/day at baseline and 12 week follow-up. Next, a systematic snapshot of the effect of CANA on key metabolites and pathways in the kidney was obtained using db/db mice. Moreover, the effects of glycine supplementation in db/db mice and human proximal tubular epithelial cells (human kidney-2 [HK-2]) cells were studied. RESULTS: Treatment of DKD patients with CANA for 12 weeks significantly reduced HbA1c from a median (interquartile range 25-75%) of 49.0 (44.0-57.0) mmol/mol (7.9%, [7.10-9.20%]) to 42.2 (39.7-47.7) mmol/mol (6.8%, [6.40-7.70%]), and reduced urinary albumin/creatinine ratio from 67.8 (45.9-159.0) mg/mmol to 47.0 (26.0-93.6) mg/mmol. The untargeted metabolomics assay showed downregulated glycolysis and upregulated fatty acid oxidation. The targeted metabolomics assay revealed significant upregulation of glycine. The kidneys of db/db mice undergo significant metabolic reprogramming, with changes in sugar, lipid and amino acid metabolism; CANA regulated the metabolic reprogramming in the kidneys of db/db mice. In particular, the pathways for glycine, serine and threonine metabolism, as well as the metabolite of glycine, were significantly upregulated in CANA-treated kidneys. Glycine supplementation ameliorated renal lesions in db/db mice by inhibiting food intake, improving insulin sensitivity and reducing blood glucose levels. Glycine supplementation improved apoptosis of human proximal tubule cells via the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway. CONCLUSIONS/INTERPRETATION: In conclusion, our study shows that CANA ameliorates DKD by inducing fasting-like and aestivation-like metabolic patterns. Furthermore, DKD was ameliorated by glycine supplementation, and the beneficial effects of glycine were probably due to the activation of the AMPK/mTOR pathway.

Tangshen formula protects against podocyte apoptosis via enhancing the TFEB-mediated autophagy-lysosome pathway in diabetic nephropathy.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease and currently there are no specific and effective drugs for its treatment. Podocyte injury is a detrimental feature and the major cause of albuminuria in DN. We previously reported Tangshen Formula (TSF), a Chinese herbal medicine, has shown therapeutic effects on DN. However, the underlying mechanisms remain obscure. AIM OF THE STUDY: This study aimed to explore the protective effect of TSF on podocyte apoptosis in DN and elucidate the potential mechanism. MATERIALS AND METHODS: The effects of TSF were assessed in a murine model using male KKAy diabetic mice, as well as in advanced glycation end products-stimulated primary mice podocytes. Transcription factor EB (TFEB) knockdown primary podocytes were employed for mechanistic studies. In vivo and in vitro studies were performed and results assessed using transmission electron microscopy, immunofluorescence staining, and western blotting. RESULTS: TSF treatment alleviated podocyte apoptosis and structural impairment, decreased albuminuria, and mitigated renal dysfunction in KKAy mice. Notably, TSF extracted twice showed a more significant reduction in proteinuria than TSF extracted three times. Accumulation of autophagic biomarkers p62 and LC3, and aberrant autophagic flux in podocytes of DN mice were significantly altered by TSF therapy. Consistent with the in vivo results, TSF prevented the apoptosis of primary podocytes exposed to AGEs and activated autophagy. However, the anti-apoptosis capacity of TSF was countered by the autophagy-lysosome inhibitor chloroquine. We found that TSF increased the nuclear translocation of TFEB in diabetic podocytes, and thus upregulated transcription of its several autophagic target genes. Pharmacological activation of TFEB by TSF accelerated the conversion of autophagosome to autolysosome and lysosomal biogenesis, further augmented autophagic flux. Conversely, TFEB knockdown negated the favorable effects of TSF on autophagy in AGEs-stimulated primary podocytes. CONCLUSIONS: These findings indicate TSF appears to attenuate podocyte apoptosis and promote autophagy in DN via the TFEB-mediated autophagy-lysosome system. Thus, TSF may be a therapeutic candidate for DN.

Huaju Xiaoji Formula Regulates ERS-lncMGC/miRNA to Enhance the Renal Function of Hypertensive Diabetic Mice with Nephropathy.

Background: Better therapeutic drugs are required for treating hypertensive diabetic nephropathy. In our previous study, the Huaju Xiaoji (HJXJ) formula promoted the renal function of patients with diabetes and hypertensive nephropathy. In this study, we investigated the therapeutic effect and regulation mechanism of HJXJ in hypertensive diabetic mice with nephropathy. Methods: We constructed a mouse hypertensive diabetic nephropathy (HDN) model by treating mice with streptozotocin (STZ) and nomega-nitro-L-arginine methyl ester (LNAME). We also constructed a human glomerular mesangial cell (HGMC) model that was induced by high doses of sugar (30 mmol/mL) and TGFß1 (5 ng/mL). Pathological changes were evaluated by hematoxylin and eosin (H&E) staining, periodic acid Schiff (PAS) staining, and Masson staining. The fibrosis-related molecules (TGFß1, fibronectin, laminin, COL I, COL IV, α-SMA, and p-smad2/3) were detected by enzyme-linked immunosorbent assay (ELISA). The mRNA levels and protein expression of endoplasmic reticulum stress, fibrosis molecules, and their downstream molecules were assessed using qPCR and Western blotting assays. Results: Administering HJXJ promoted the renal function of HDN mice. HJXJ reduced the expression of ER stress makers (CHOP and GRP78) and lncMGC, miR379, miR494, miR495, miR377, CUGBP2, CPEB4, EDEM3, and ATF3 in HDN mice and model HGMCs. The positive control drugs (dapagliflozin and valsartan) also showed similar effects after treatment with HJXJ. Additionally, in model HGMCs, the overexpression of CHOP or lncMGC decreased the effects of HJXJ-M on the level of fibrosis molecules and downstream target molecules. Conclusion: In this study, we showed that the HJXJ formula may regulate ERS-lncMGC/miRNA to enhance renal function in hypertensive diabetic mice with nephropathy. This study may act as a reference for further investigating whether combining HJXJ with other drugs can enhance its therapeutic effect. The findings of this study might provide new insights into the clinical treatment of hypertensive diabetic nephropathy with HJXJ.

Neferine inhibits the progression of diabetic nephropathy by modulating the miR-17-5p/nuclear factor E2-related factor 2 axis.

OBJECTIVE: To investigate the effect of Neferine (Nef) on diabetic nephropathy (DN) and to explore the mechanism of Nef in DN based on miRNA regulation theory. METHODS: A DN mouse model was constructed and treated with Nef. Serum creatinine (Crea), blood urea (UREA) and urinary albumin were measured in mice by kits, and renal histopathological changes and fibrosis were observed by hematoxylin-eosin staining and Masson staining. Renal tissue superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) activities were measured by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to detect the expression of nuclear factor E2-related factor 2 (Nrf2)/ heme oxygenase 1 (HO-1) signaling pathway-related proteins in kidney tissues. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-17-5p in kidney tissues. Subsequently, a DN in vitro model was constructed by high glucose culture of human mesangial cells (HMCs), cells were transfected with miR-17-5p mimic and/or treated with Nef, and we used qRT-PCR to detect cellular miR-17 expression, flow cytometry to detect apoptosis, ELISAs to detect cellular SOD, MDA, and GSH-Px activities, Western blots to detect Nrf2/HO-1 signaling pathway-related protein expression, and dual luciferase reporter gene assays to verify the targeting relationship between Nrf2 and miR-17-5p. RESULTS: Administration of Nef significantly reduced the levels of blood glucose, Crea, and UREA and the expression of miR-17-5p, improved renal histopathology and fibrosis, significantly reduced MDA levels, elevated SOD and GSH-Px activities, and activated Nrf2 expression in kidney tissues from mice with DN. Nrf2 is a post-transcriptional target of miR-17-5p. In HMCs transfected with miR-17-5p mimics, the mRNA and protein levels of Nrf2 were significantly suppressed. Furthermore, miR-17-5p overexpression and Nef intervention resulted in a significant increase in high glucose-induced apoptosis and MDA levels in HMCs and a significant decrease in the protein expression of HO-1 and Nrf2. CONCLUSION: Collectively, these results indicate that Nef has an ameliorative effect on DN, and the mechanism may be through the miR-17-5p/Nrf2 pathway.

Exploring the molecular mechanism of berberine for treating diabetic nephropathy based on network pharmacology.

BACKGROUND AND PURPOSE: Diabetic nephropathy (DN) is a prevalent complication of diabetes mellitus characterized by hyperglycemia, hyperlipidemia, albuminuria and edema. Increasing evidence indicated that berberine (BBR) could alleviate the occurrence and development of DN. However, the molecular mechanism underlying the beneficial effects of BBR in the treatment of DN remains unclear. METHODS: The online public databases were chosen to screen the relevant targets of BBR and DN and the screened overlapped targets were analyzed by GO enrichment analysis, KEGG enrichment analysis and protein-protein interaction network analysis. The interaction between BBR and the key proteinwas verified by molecular docking and cellularthermalshiftassay. Additionally, the expression of key proteins and related indicators of DN were verified by immunofluorescence and western blot in vitro and in vivo. RESULTS: We successfully identified 92 overlapped targets of BBR and DN based on network pharmacology. Notably, VEGFR2 was identified to be the main target of BBR. Meanwhile, we found that BBR exhibited a high binding affinity to VEGFR2 protein, as confirmed by molecular docking and CETSA. This binding led to interfering with the PI3K/AKT/mTOR signaling pathway. In addition, we found that BBR could inhibit the abnormal proliferation of mesangial cells and reduce the expression of downstream pathway protein in vitro and in vivo. Finally, BBR was found to effectively lower the level of blood glucose and improve kidney function in mice, highlighting its potential as a therapeutic agent for the treatment of DN. CONCLUSION: Berberine interfered the PI3K/AKT/mTOR signaling pathway via targeting VEGFR2 protein, further led to the inhibition of abnormal proliferation of mesangial cells and ultimately resulted in improved renal function.

The effect of Abelmoschus esculentus L. (Okra) extract supplementation on glycaemic control, inflammation, kidney function and expression of PPAR-α, PPAR-γ, TGF-ß and Nrf-2 genes in patients with diabetic nephropathy: a triple-blind, randomised, placebo-controlled trial.

The present study was carried out to evaluate the effects of okra extract supplementation on kidney function, glycaemic control, inflammation and gene expression in patients with diabetic nephropathy (DN). A total of sixty-four DN patients based on the inclusion and exclusion criteria were recruited in this triple-blind placebo-controlled randomised clinical trial. Participants were randomly allocated to receive a 125-mg capsule of dried okra extract (DOE) (n 32) or placebo (n 32) for 10 weeks. At the baseline and endpoint of the trial, kidney function, glycaemic indices, inflammation and gene expression were evaluated. Statistical analysis showed that fasting blood glucose, HbA1c and insulin resistance significantly reduced in the DOE group although between-group analysis did not show any significant difference. Also, no significant difference was observed in urine protein, urine creatinine and high-sensitivity C-reactive protein between the two groups. Furthermore, gene expression of PPAR-α, PPAR-γ, transforming growth factor-beta and Nrf-2 did not affect the end of the trial in comparison with the baseline. According to the present study, DOE did not have impressive effects on kidney function, inflammation, glycaemic management and gene expression in patients with DN.

Terpenoids in Diabetic Nephropathy: Advances and Therapeutic Opportunities.

Diabetic nephropathy (DN) is the foremost ailment resulting in end-stage renal damage. Chronic hyperglycaemia and hyperlipidaemia are the foremost reason for disease progression. The disease is characterized by the severity of albuminuria and cardiovascular disorders. Approximately 20 to 40% of the global prevalence of DN is mostly reported to occur in individuals with diabetes, and nearly 28% of DN occurs in individuals with other renal disorders. The pathological mechanism is very complex, involving innumerable targets and leading to multiple pharmacological effects. Thus, the scientific community is forced to work in search of safe and potent therapeutics that can tackle the complex pathology of DN effectively. The secondary plant metabolites categorized as terpenoids gained attention as potential therapeutics contrary to others for the management of diabetic nephropathy and other associated syndromes by their strong antioxidant activity and inhibition of advanced glycation and its associated products. This review focused on herbal therapeutics for the management of diabetic nephropathy. Moreover, different types of terpenoids, their biological sources, and proposed mechanisms of action are explored for the development of a novel pharmacophore for diabetic nephropathy.

Molecular mechanism of Gan-song Yin inhibiting the proliferation of renal tubular epithelial cells by regulating miR-21-5p in adipocyte exosomes.

ETHNOPHARMACOLOGICAL RELEVANCE: Gan-song Yin is derived from the classic ancient prescription " Gan-song pill " for the treatment of wasting-thirst in Ningxia combined with the characteristic "fragrant medicine". It is clinically used for the treatment of early renal fibrosis caused by diabetic nephropathy. Previous studies have shown that it has a good effect and great potential in the prevention and treatment of diabetic nephropathy, but its mechanism research is still limited. AIM OF THE STUDY: To investigate the mechanism of GSY to improve DN by interfering with miR-21-5p and glycolipid metabolism in adipocyte exosomes using 3T3-L1 and TCMK-1 co-culture system. MATERIALS AND METHODS: The co-culture system of 3T3-L3 and TCMK-1 was established, the IR model was established, and the stability, lipid drop change, glucose consumption, triglyceride content, cell viability, cell cycle and apoptosis level, protein content and mRNA expression of the IR model were detected. RESULTS: GSY inhibited 3T3-L1 activity, increased glucose consumption and decreased TG content. Decreased TCMK-1 cell viability, inhibited apoptosis, cell cycle arrest occurred in G0/G1 phase and S phase. Adipocyte IR model and co-culture system were stable within 48 h. After GSY intervention, lipid droplet decomposition and glucose consumption increased. The TG content of adipocytes increased, while the TG content of co-culture system decreased. GSY can regulate the expression of TGF-ß1/SMAD signaling pathway protein in IR state. After GSY intervention, the expression of miR-21-5p was increased in 3T3-L1 and Exo cells, and decreased in TCMK-1 cells. CONCLUSIONS: GSY can regulate TGF-ß1/SMAD signaling pathway through the secretion of miR-21-5p from adipocytes, protect IR TCMK-1, regulate the protein and mRNA expression levels of PPARγ, GLUT4, FABP4, and improve glucose and lipid metabolism.

Mechanistic role of Syzygium cumini (L.) Skeels in glycation induced diabetic nephropathy via RAGE-NF-κB pathway and extracellular proteins modifications: A molecular approach.

ETHNOPHARMACOLOGY RELEVANCE: Syzygium cumini (L.) Skeels (SC), an ancient medicinal plant, is used as a complementary and alternative medicine for treating diabetes mellitus and its associated complications, such as diabetic nephropathy (DN). Phytochemicals present in SC homeopathic formulations possess anti-glycemic, anti-glycation, anti-inflammatory, and antioxidant properties. Additionally, the non-enzymatic formation of advanced glycation end products (AGEs) increases during hyperglycemia in diabetes. AGEs interaction with their receptor of AGEs (RAGE) promotes inflammation via Nuclear Factor-κB (NF-κB) and the accumulation of Extracellular Matrix (ECM) proteins, contributing to the renal dysfunction in DN. However, the molecular mechanism through which SC formulations interact with the AGEs-RAGE-NF-κB pathway has not yet been investigated. AIM: This study aims to examine the impact of SC formulations on the RAGE-NF-κB pathway and ECM protein modifications in glycation-induced DN using a molecular approach. MATERIALS AND METHODS: Human serum albumin (10 mg/ml) was glycated with MGO (55 mM) in the presence of SC formulations - Mother tincture (MT), 30C, 200C for 7 days. Glycated samples were added to renal cells (HEK 293) for 24 h. Subsequently, cellular gene and protein expressions of RAGE, NF-κB, vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), collagen IV (Col IV), and fibronectin were determined using RT-qPCR and Western blot analysis. The immunofluorescence, luciferase assay, and chromatin immunoprecipitation techniques were employed to gain insights into glycation-induced NF-κB nuclear translocation, transcriptional activity, and its effect on RAGE promoter activity in SC-treated cells. RESULTS: SC formulations significantly downregulated glycation-induced elevated levels of RAGE and NF-κB. Mechanistically, SC formulations prevented NF-κB nuclear translocation, transcriptional activity, and RAGE promoter activity. Also, SC formulations significantly attenuated glycation-enhanced expressions of inflammatory cytokines (IL-6, TNF-α, and VEGF) and ECM proteins (Col IV and fibronectin). CONCLUSION: Our findings enlighten the molecular mechanism of SC in DN by targeting the AGEs-RAGE-NF-κB signaling pathway, inflammatory responses, and ECM accumulation. Hence, the study validates the protective role of SC formulations and signifies its novel potential for treating DN.

Modified Hu-lu-ba-wan protects diabetic glomerular podocytes via promoting PKM2-mediated mitochondrial dynamic homeostasis.

BACKGROUND: Mitochondrial dysfunction is implicated in the progression of diabetic kidney disease (DKD). Damaged mitochondria produce excessive reactive oxygen species (ROS) that can cause apoptosis. Mitochondrial dynamics control the quality and function of mitochondria. Targeting mitochondrial dynamics may reduce ROS-induced apoptosis and improve renal injury in DKD. Modified Hu-lu-ba-wan (MHLBW) shows distinct clinical effects on DKD patients, which are related to its role in antioxidant stress modulation. However, the relevant mechanisms of MHLBW have not been clearly explored. PURPOSE: This study was aimed to evaluate the therapeutic effects of MHLBW on spontaneous DKD mice and clarify the potential mechanisms. METHODS: The main components of MHLBW were identified by HPLC. Using db/db mice as DKD models, we evaluated the therapeutic effects of MHLBW on mice after an 8-week administration. We investigated the molecular mechanism of MHLBW in regulating mitochondrial dynamic homeostasis, podocyte apoptosis, and glomerular damage. After that, computational docking analysis and in vitro experiments were conducted for further mechanism verification. RESULTS: Intragastric administration of MHLBW for 8 weeks in db/db mice significantly improved glucose metabolism, basement membrane thickening, mesangial expansion, glomerular fibrosis, and podocyte injury. MHLBW can reverse podocyte apoptosis via promoting mitochondrial dynamic homeostasis, which was related to regulating the PKM2/ PGC-1α/Opa1 pathway. Berberine (BBR), one of the components of MHLBW, exhibited preeminent affinity with PKM2 as reflected by computational docking analysis. In cultured podocytes, BBR can also prevent apoptosis by promoting PKM2-mediated mitochondrial dynamic homeostasis. CONCLUSION: Our study demonstrates that MHLBW can treat DKD by inhibiting glomerular damage and podocyte apoptosis through positive regulation of PKM2-mediated mitochondrial dynamic homeostasis. These results may provide a potential strategy against DKD.

Chrysophanol ameliorates oxidative stress and pyroptosis in mice with diabetic nephropathy through the Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 signaling pathway.

Diabetic nephropathy (DN), a microvascular complication of diabetes, increases the risk of all-cause diabetes and cardiovascular mortalities. Moreover, oxidative stress and pyroptosis play important roles in the pathogenesis of DN. Rhubarb is widely used in traditional medicine, and chrysophanol (Chr), a free anthraquinone compound abundant in rhubarb, exhibits potent antioxidant properties and ameliorates renal fibrosis. Therefore, this study aimed to investigate the effects of Chr on renal injury, oxidative stress, and pyroptosis in mice with DN. A DN model was established by feeding the mice a high-sugar and fat diet and injecting them with 50 mg/kg streptozotocin as a positive control. The DN mice had significantly impaired renal function, thickened glomerular thylakoids and basement membranes, increased fibrous tissue, and inflammatory cell infiltration. Superoxide dismutase (SOD) levels were reduced, malondialdehyde (MDA) levels were increased, interleukin (IL)-1ß and IL-18 increased, and cleaved caspase-1, caspase-1, and gasdermin D (GSDMD) involved in the process of pyroptosis were upregulated in DN. Kelch-like ECH-associated protein 1 (Keap1) expression was upregulated, and nuclear factor erythroid 2-related factor 2 (Nrf2) expression was downregulated. Compared to those in the DN group, the Chr-treated mice with DN had improved renal dysfunction, weakened glomerular thylakoid and basement membrane thickening, and reduced fibrous tissue proliferation and inflammatory cell infiltration. Additionally, Chr increased SOD levels, decreased MDA, IL-1ß, and IL-18, down-regulated caspase-1, cleaved caspase-1, GSDMD, and Keap1 expression, and upregulated Nrf2 expression, which reversed the DN. Therefore, Chr reduced oxidative stress and pyroptosis in DNmice by activating the Keap1/Nrf2 pathway.

Effects of total flavones of Abelmoschus manihot (L.) on the treatment of diabetic nephropathy via the activation of solute carriers in renal tubular epithelial cells.

As a traditional Chinese medicine, Huangkui capsule (HKC) has been used to treat patients with kidney diseases, including diabetic nephropathy (DN). We have recently demonstrated that HKC could re-regulate the activities of solute carriers (SLC)s in proximal and distal convoluted tubules of kidneys in regression of the development of DN. The main active chemical constituents of HKC are the flavones of Abelmoschus manihot (L.). The current study aims to further evaluate the efficacy of total flavones of A. manihot (TFA) in the regression of DN by analyzing SLC activities in proximal and distal convoluted tubules of kidneys. TFA (0.076 g/kg/d) or vehicle was administered in db/db mice, the animal model of type 2 diabetes and DN, daily via oral gavage for four weeks. Blood glucose levels and urinary albumin-to-creatinine ratio (UACR) were measured and used for the determination of T2D and DN. Ten SLCs, including slc2a2, slc4A1, slc5a2, slc5A3, slc5a8, slc6a20, slc27a2, slc12a3, slc34a1 and slc38a2 were highly expressed in proximal and distinct convoluted tubules of kidneys. Their expression at mRNA and protein levels before and after TFA treatment were analyzed with real-time RT-PCR and immunohistochemistry. Data showed that UACR in the db/db mice after TFA treatment was significantly decreased. Compared with the group of non-diabetic control, slc2a2, slc4A1, slc5a2, slc5A3, slc5a8, slc6a20, slc27a2, slc12a3, slc34a1 and slc38a2 in the group of DN were down-regulated but up-regulated after TFA treatment. Further analyses of whole kidney sections indicated that the numbers and structures of the nephron in db/db mice was increased and improved after TFA treatment. Thereby, the current study provides further evidence that the flavones in A. manihot have pharmacological effects on the treatment of DN by improving the biological function of SLCs in kidneys.

Crocin Ameliorates Diabetic Nephropathy through Regulating Metabolism, CYP4A11/PPARγ, and TGF-ß/Smad Pathways in Mice.

INTRODUCTION: Crocin is one of the main components of Crocus sativus L. and can alleviate oxidative stress and inflammation in diabetic nephropathy (DN). However, the specific mechanism by which crocin treats DN still needs to be further elucidated. METHOD: In the present study, a mouse model of DN was first established to investigate the therapeutic effect of crocin on DN mice. Subsequently, non-targeted metabolomics techniques were used to analyze the mechanisms of action of crocin in the treatment of DN. The effects of crocin on CYP4A11/PPARγ and TGF-ß/Smad pathway were also investigated. RESULT: Results showed that crocin exhibited significant therapeutic and anti-inflammatory, and anti-oxidative effects on DN mice. In addition, the non-targeted metabolomics results indicated that crocin treatment affected several metabolites in kidney. These metabolites were mainly associated with biotin metabolism, riboflavin metabolism, and arachidonic acid metabolism. Furthermore, crocin treatment upregulated the decreased levels of CYP4A11 and phosphorylated PPARγ, and reduced the increased levels of TGF-ß1 and phosphorylated Smad2/3 in the kidneys of DN mice. CONCLUSION: In conclusion, our study validated the considerable therapeutic, anti-inflammatory, and antioxidative impacts of crocin on DN mice. The mechanism of crocin treatment may be related to the regulation of biotin riboflavin and arachidonic acid metabolism, the activation of CYP4A11/PPARγ pathway, and the inhibition of TGF-ß/Smad pathway in the kidney.

Rosa laevigata Michx. Polysaccharide Ameliorates Diabetic Nephropathy in Mice through Inhibiting Ferroptosis and PI3K/AKT Pathway-Mediated Apoptosis and Modulating Tryptophan Metabolism.

Diabetic nephropathy (DN) is a metabolic disease wherein chronic hyperglycemia triggers various renal cell dysfunctions, eventually leading to progressive kidney failure. Rosa laevigata Michx. is a traditional Chinese herbal medicine. Many studies have confirmed its antioxidative, anti-inflammatory, and renoprotective effects. However, the effects and mechanisms of Rosa laevigata Michx. polysaccharide (RLP) in DN remain unclear. In this study, a DN mouse model was established to investigate the therapeutic effect of RLP on DN mice. Then, nontargeted metabolomics was used to analyze the potential mechanism of RLP in the treatment of DN. Finally, the effects of RLP on ferroptosis and the PI3K/AKT pathway were investigated. The results demonstrated that RLP effectively alleviated renal injury and reduced inflammation and oxidative stress in the kidney. In addition, nontargeted metabolomic analysis indicated that RLP could modulate riboflavin metabolism and tryptophan metabolism in DN mice. Notably, ferroptosis and PI3K/AKT pathway-mediated apoptosis in the kidney were also ameliorated following RLP treatment. In conclusion, this study confirmed that RLP had a significant therapeutic effect on DN mice. Furthermore, RLP treatment modulated tryptophan metabolism and inhibited ferroptosis and PI3K/AKT pathway-mediated apoptosis in the kidney.

Ecliptasaponin A attenuates renal fibrosis by regulating the extracellular matrix of renal tubular cells.

Renal fibrosis is the most common manifestation of end-stage renal disease (ESRD), including diabetic kidney disease (DKD), but there is no effective treatment in renal fibrosis. Natural products are a rich source of clinical drug research and have been used in the clinical research of various diseases. In this study, we searched for traditional Chinese medicine monomers that attenuate fibrosis and assessed their effect on the fibrosis marker connective tissue growth factor (CTGF) in cells which we found ecliptasaponin A. Subsequently, we evaluated the effect of ecliptasaponin A on renal fibrosis in the classic renal fibrosis unilateral ureteral obstruction (UUO) mouse model and found that ecliptasaponin A could reduce the renal collagen fiber deposition and renal extracellular matrix (ECM) protein expression in UUO mice. In vitro, ecliptasaponin A can inhibit ECM protein expression in human kidney-2 (HK-2) cells induced by transforming growth factor-beta1 (TGFß1). To further clarify the mechanism of ecliptasaponin A in attenuating renal fibrosis, we performed transcriptome sequencing of HK-2 cells treated with TGFß1 and ecliptasaponin A. The functions and pathways were mainly enriched in the extracellular matrix and TGFß signalling pathway. Matrix metalloproteinase 10 (MMP10) and matrix metalloproteinase 13 (MMP13) are the main differentially expressed genes in extracellular matrix regulation. Then, we measured MMP10 and MMP13 in the cells and found that ecliptasaponin A had a significant inhibitory effect on MMP13 expression but not on MMP10 expression. Furthermore, we overexpressed MMP13 in HK-2 cells treated with TGFß1 and found that MMP13 promoted HK-2 cell injury. Our findings suggest that ecliptasaponin A can attenuate renal fibrosis, which may provide a new method for treating renal fibrosis clinically.

Poricoic acid A induces mitophagy to ameliorate podocyte injury in diabetic kidney disease via downregulating FUNDC1.

Diabetic kidney disease (DKD) is a devastating complication of diabetes mellitus (DM) and is the most prevalent chronic kidney disease (CKD). Poricoic acid A (PAA), a component isolated from Traditional Chinese Medicine (TCM) Poria cocos, has hypoglycaemic and anti-fibrosis effects. However, the role of PAA in DKD remains largely unclear. To mimics an in vitro model of DKD, the mouse podocyte MPC5 cells were treated with high glucose (25 mM; HG) for 24 h. CCK-8 and flow cytometry assays were conducted for assessing MPC5 cell viability and apoptosis. Meanwhile, streptozotocin (STZ) was used to induce experimental DKD in mice by intraperitoneal injection. PAA notably inhibited the apoptosis and inflammation, reduced the generation of ROS, and elevated the MMP level in HG-treated MPC5 cells. Moreover, PAA obviously reduced blood glucose and urine protein levels, inhibited renal fibrosis in DKD mice. Meanwhile, PAA markedly increased LC3 and ATG5 levels and declined p62 and FUNDC1 levels in HG-treated MPC5 cells and in the kidney tissues of DKD mice, leading to the activation of cell mitophagy. Furthermore, the downregulation of FUNDC1 also inhibited apoptosis, inflammation, and promoted mitophagy in HG-treated MPC5 cells. As expected, the knockdown of FUNDC1 further enhanced the protective role of PAA in MPC5 cells following HG treatment, indicating that induction of mitophagy could attenuate podocyte injury. Collectively, PAA could exert beneficial effects on podocyte injury in DKD by promoting mitophagy via downregulating FUNDC1. These findings suggested that PAA may have great potential in alleviating kidney injury in DKD.

Inhibition of Autophagy in Renal Cells With Human, Urine-derived, Stem-cell Exosomes to Improve Diabetic Nephropathy.

Context: Clinicians can use stem cells to repair kidney injury. The kidneys' exosome secretions hold the secret to this therapeutic impact. Exosomes from urine-derived stem cells can prevent and treat glomerular damage that diabetes can cause, but the underlying process has remained a mystery. Objective: The study aimed to investigate the protective impact of exosomes from urine-derived stem cells (USCs) against diabetic nephropathy (DN) and to determine the mechanisms involved. Design: The research team performed an animal study. Setting: The study took place at the Affiliated Hospital of Jiujiang University in Jiujiang, Jiangxi, China. Animals: The animals were rats, SD male rats, weighing 200-220g, 40 animals, purchased from Weitong Lihua Experimental Animal Technology Co., Ltd. (certificate number: SCXK (Beijing) 2021-0006). Intervention: Except for a control group, the rats in the groups had induced DN. The five groups, with 10 rats each, were: (1) the negative control group, which received 0.2 ml of PBS solution; (2) the DN group, a second negative control group, which received 0.2 ml of PBS solution, (3) the inhibitor group, an intervention group that received 20 mg/kg of autophagy inhibitor; (4) the exosomes group, an intervention group that received 100 ug/kg of exosomes; and (5) the exosomes + inhibitor group, an intervention group that received 100 ug/kg of exosomes + 20 mg/kg of autophagy inhibitor. From week 8, for four weeks the team injected the inhibitor, exosomes, and exosomes + inhibitor groups with the appropriate treatments using the rats' tail veins. Outcome Measures: The research team: (1) examined the USCs in the exosomes of stem cells; (2) assessed the rats' weights and fasting blood glucose (FBG), using a blood glucose meter; (3) used Coomassie brilliant blue (CBB) staining to determine the amount of protein in the rats' urine and assessed their biochemical indexes; and (4) used Western blot (WB) and a quantitative polymerase chain reaction (Q-PCR) to detect autophagy and the signal transduction pathway. Results: Human exosomes from USCs alleviated injury in the rats that DN caused by reducing urinary-protein levels, serum creatinine (SCR), blood urea nitrogen (BUN), glomerular cell accumulation, and kidney weights. In rats with induced DN, the exosomes + inhibitor significantly reduced the activation of the mTOR signaling pathway, reduced the autophagy of their kidney cells, increased the protein expression of Bcl-2 in the kidney tissues, and lessened the damage to glomerular cells. Conclusions: Human urine-derived stem cell exosomes can significantly reduce the activation of the mTOR signaling pathway, reduce the autophagy of rats' kidney cells, increase the protein expression of LC3B in kidney tissues, and reduce the damage to glomerular cells. By blocking the mTOR signaling pathway, human urogenic exosomes can alleviate the signs and symptoms of DN.