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.

Reversal effect of quercetin on multidrug resistance via FZD7/ß-catenin pathway in hepatocellular carcinoma cells.

BACKGROUND: Chemotherapy has been widely used to treat cancer, but the appearance of multidrug resistance (MDR) is the biggest obstacle to successful chemotherapy. One of the conventional mechanisms of MDR is overexpression of ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp/ABCB1) and multidrug resistance-associated proteins (MRPs/ABCCs) that limits the prolonged and efficient use of chemotherapeutic drugs. To enhance the chemosensitivity of tumor cells, attentions have been focused on effective MDR modulators. PURPOSE: This study aimed to investigate the reversal effect of quercetin on MDR, and explored its mechanism of action in vitro. STUDY DESIGN/METHODS: The effect and mechanism of quercetin on MDR was examined by using MTT assay, flow cytometry, real-time PCR and western blot analysis in human hepatocellular carcinoma cells. RESULTS: Our data found that the intracellular accumulation of rhodamine-123 (Rh123) and doxorubicin (ADR) were increased, the sensitivity of BEL/5-FU cells to chemotherapeutic drugs were increased, and the expressions of ABCB1, ABCC1 and ABCC2 were all down-regulated, which indicated that the functions and expressions of ABCB1, ABCC1 and ABCC2 efflux pump were inhibited by quercetin treatment. Moreover, the suppression of ABCB1, ABCC1 and ABCC2 by quercetin was dependent on the FZD7 through the Wnt/ß-catenin pathway. Further research revealed that reduction of FZD7 by RNA interference (siFZD7) enhanced the sensitivity to chemotherapeutic drugs, increased the cellular accumulation of Rh123 and ADR, and induced inhibitory effects on the expression of FZD7, ABCB1, ABCC1, ABCC2 and ß-catenin, similar to quercetin. In the meanwhile, overexpression of FZD7 showed the inversely effect on the expressions. Interesting, it was confirmed that quercetin could inhibit the expression levels of FZD7, ABCB1, ABCC1, ABCC2 and ß-catenin in BEL-7402 cells; furthermore, treatment by quercetin combined with siFZD7 in BEL/5-FU cells, the expressions of these genes were effectively decreased in comparison to quercetin combined with siRNA negative control (sncRNA). CONCLUSION: Overall, these data suggested the effectiveness of using quercetin, at least in part, via inhibiting FZD7 to combat chemoresistance and showed that quercetin could be developed into an efficient natural sensitizer for resistant human hepatocellular carcinoma.

Berberine exerts renoprotective effects by regulating the AGEs-RAGE signaling pathway in mesangial cells during diabetic nephropathy.

In this study, we explored the effect of berberine treatment on the AGEs-RAGE pathway in a rat model of diabetic nephropathy, and we investigated the mechanism by which key factors caused kidney injury and the effects of berberine. In vivo, berberine improved fasting blood glucose, body weight, the majority of biochemical and renal function parameters and histopathological changes in the diabetic kidney. Western blotting and immunohistochemistry revealed significant increases in the levels of AGEs, RAGE, P-PKC-ß and TGF-ß1 in injured kidneys, and these levels were markedly decreased by treatment with berberine. In vitro, berberine inhibited mesangial cell proliferation. Cells treated with berberine showed reduced levels of AGEs, accompanied by decreased RAGE, p-PKC and TGF-ß1 levels soon afterwards. Berberine exhibited renoprotective effects in diabetic nephropathy rats, and the molecular mechanism was associated with changes in the levels and regulation of the AGEs-RAGE-PKC-ß-TGF-ß1 signaling pathway.

Renoprotective effect of berberine via regulating the PGE2 -EP1-Gαq-Ca(2+) signalling pathway in glomerular mesangial cells of diabetic rats.

G-protein coupled receptor-mediated pathogenesis is of great importance in the development of diabetic complications, but the detailed mechanisms have not yet been clarified. Therefore, we aimed to explore the roles of the prostaglandin E2 receptor 1 (EP1)-mediated signalling pathway and develop a corresponding treatment for diabetic nephropathy (DN). To create the DN model, rats fed a high-fat and high-glucose diet were injected with a single dose of streptozotocin (35 mg/kg, i.p.). Then, rats were either treated or not with berberine (100 mg/kg per day, i.g., 8 weeks). Cells were isolated from the renal cortex and cultured in high-sugar medium with 20% foetal bovine serum. Prostaglandin E2 (PGE2 ) levels were determined by ELISA, and cells were identified by fluorescence immunoassay. We measured the biochemical characteristics and observed morphological changes by periodic-acid-Schiff staining. The expression of the EP1 receptor and the roles of GRK2 and ß-arrestin2 were identified using western blotting and flow cytometry. Downstream proteins were detected by western blot, while molecular changes were assessed by ELISA and laser confocal scanning microscopy. Berberine not only improved the majority of biochemical and renal functional parameters but also improved the histopathological alterations. A significant increase in PGE2 level, EP1 membrane expression and Gαq expression, and concentration of Ca(2+) were observed, accompanied by increased GRK2 and ß-arrestin2 levels soon afterwards. Berberine decreased the abnormal concentration of Ca(2+) , the increased levels of PGE2 , the high expression of EP1 and Gαq and suppressed the proliferation of mesangial cells. The EP1 receptor, a critical therapeutic target of the signalling pathway, contributed to mesangial cell abnormalities, which are linked to renal injury in DN. The observed renoprotective effects of berberine via regulating the PGE2 -EP1-Gαq-Ca(2+) signalling pathway indicating that berberine could be a promising anti-DN medicine in the future.

Renoprotective effects of berberine and its potential effect on the expression of ß-arrestins and intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in streptozocin-diabetic nephropathy rats.

BACKGROUND: Berberine has been shown to exert protective effects against diabetic nephropathy (DN), but the mechanisms involved have not been fully characterized. The aim of the present study was to explore the effects of berberine on the expression of ß-arrestins, intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in DN rat kidneys and investigate the underlying molecular mechanisms. METHODS: To create the DN model, rats fed a high-fat and high-glucose diet were injected with a single dose of streptozotocin (35 mg/kg, i.p.). Then, DN rats were either treated or not with berberine (50, 100, 200 mg/kg per day, i.g., 8 weeks). Periodic acid-Schiff staining was used to evaluate renal histopathological changes. Renal tissue levels of ß-arrestin 1 and ß-arrestin 2 were determined by Western blot analysis, whereas immunohistochemistry was used to determine renal ICAM-1 and VCAM-1 levels. RESULTS: Berberine (100, 200 mg/kg) ameliorated the histopathological changes in the diabetic kidney. Western blot analysis revealed significant increases in ICAM-1 and VCAM-1 levels in the kidneys of DN rats, which were reversed by treatment with 100 and 200 mg/kg berberine. In addition, berberine treatment (50, 100, 200 mg/kg) increased diabetic-induced decreases in ß-arrestin 1 and ß-arrestin 2. CONCLUSIONS: Berberine exhibited renoprotective effects in DN rats. The underlying molecular mechanisms may be associated with changes in the levels and regulation of ß-arrestin expression, as well as ICAM-1 and VCAM-1 levels in the rat kidney.

[Regulatory effect of compound Coptidis Rhizoma capsule on unbalanced expression of renal tissue TGF-ß1/BMP-7 and Smad signaling pathway in rats with early diabetic nephropathy].

OBJECTIVE: To investigate the effect of compound Coptidis Rhizoma capsule (CCRC) on unbalanced expression of renal tissue TGF-ß1/BMP-7 and Smad signaling pathway in rats with early diabetic nephropathy (DN), and discuss CCRC's effect on DN rats with early diabetic nephropathy and its possible mechanism. METHOD: DN model rats were established by injecting streptozotocin (STZ). The rats were randomly divided into seven groups: the normal group, the model group, the enalapril treatment group, the xiaoke pill treatment group and three CRCC treatment groups. They were orally administered once a day for five weeks. The fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (Scr), insulin (Ins), 24 h urinary protein (24 h Upro) and 24 h urinary microalbumin (24 h UmAlb) were tested. The pathological changes in renal tissues were examined by optical microscopy. Immuno- histochemical measures were used to detect the expressions of TGF-ß1, BMP-7, Smad2/3, Smad1/5, and Smad7 protein, and RT-PCR was used to detect TGF-ß1 mRNA and BMP-7 mRNA in renal tissues. RESULT: Compared with model group, BUN, Scr, Ins, 24 h Upro and 24 h UmAlb levels decreased at different degrees in CCRC treatment groups; the abnormal pathomorphology in renal tissue was improved; immunohistochemistry results showed that the expression of TGF-ß1 and Smad2/3 were reduced, while the expression of BMP-7, Smad1/5 and Smad7 increased in CRCC treatment groups; the expression of TGF-ß1 mRNA were reduced, but the expression of BMP-7 mRNA had no obvious change in CRCC treatment groups. CONCLUSION: CRCC can improve the early renal function, delay the progression of chronic renal pathology and maintain the dynamic balance of TGF-ß1/BMP-7 expression in renal tissues of DN rats. The mechanism may be related to down-regulation of renal TGF-ß1 and up-regulation of BMP-7 through Smad signaling pathway.

Berberine as a promising anti-diabetic nephropathy drug: An analysis of its effects and mechanisms.

Diabetic nephropathy is a progressive kidney disorder and is pathologically characterized by thickened glomerular and tubular basement membranes, accumulation of the extracellular matrix and increased mesangial hypertrophy. Growing evidence has suggested that diabetic nephropathy is induced by multiple factors, such as dyslipidemia, hyperglycemia, hemodynamic abnormalities and oxidative stress, based on genetic susceptibility. Berberine (BBR; [C20H18NO4](+)), an isoquinoline alkaloid, is the major active constituent of Rhizoma coptidis and Cortex phellodendri. Recent studies have demonstrated that berberine has various pharmacological activities, including lowering blood glucose, regulating blood lipids and reducing inflammation in addition to its antioxidant activity. These findings suggest that berberine has potential applications as a therapeutic drug for diabetic nephropathy, and has significant research value. However, the possible mechanisms have not been fully established. The purpose of this paper is to investigate the renoprotective mechanisms of berberine in diabetic nephropathy and highlight the importance of berberine as a potential therapeutic reagent for diabetic nephropathy treatment.

[Regulatory effect of berberine on unbalanced expressions of renal tissue TGF-beta1/SnoN and smad signaling pathway in rats with early diabetic nephropathy].

OBJECTIVE: To investigate the effect of berberine (BBR) on unbalanced expression of renal tissue TGF-beta1/SnoN and Smad signal pathway in rats with early diabetic nephropathy (DN), and discuss BBR's effect on DN rats with early diabetic nephropathy and its possible mechanism. METHOD: DN rat model were established by injecting streptozotocin (STZ). The rats were divided into six groups: the control group, the model group, three BBR (50, 100, 200 mg x kg(-1)) treatment groups and the enalapril treatment group. They were orally administered once a day for five weeks. The fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (Scr), urinary protein (24 h Upro) and urinary microalbumin (24 h UmAlb) were tested. The pathological changes in renal tissues were examined by optical microscopy. Immunohistochemical measures were used to detect the expressions of TGF-beta1, SnoN, Smad2/3 and Smad7 protein, and RT-PCR was used to detect TGF-beta1 mRNA in renal tissues. RESULT: Compared with the model group, BBR-treated groups showed significant decrease in FBG, BUN, Scr, 24 h Upro, 24 h UmAlb, TGF-beta1 protein, mRNA and Smad2/3 protein, abnormal morphological improvement in renal tissues, and notable increase in the expressions of SnoN and Smad7 protein. CONCLUSION: BBR can maintain the dynamic balance in TGF-beta1/SnoN expression in renal tissues through Smad signaling pathway, so as to mitigate renal functional disorder in DN rats and delay DN and its development.

[Effect of berberine on expression of transforming growth factor-beta1 and type IV collagen proteins in mesangial cells of diabetic rats with nephropathy].

OBJECTIVE: To explore the effect and mechanism of berberine on diabetic nephropathy in experimental rats. METHOD: The rat model of diabetic nephropathy was induced by injection of streptozocin (STZ). The rats were divided into 6 groups: control group, model group, 3 berberine treatment groups and Xiaoke Wan (XKW) treatment group. The fasting blood glucose (FBG), kidney weight/body weight (KW/BW), blood urea nitrogen (BUN), creatinine (Cr) and urinary protein (Upro) were tested 8 weeks later. The expression of transforming growth factor-beta1 (TGF-beta1) and type IV collagen (IV-C) proteins in renal tissue of diabetic rats with nephropathy were observed by optical micrography. RESULT: Berberine could reduce the levels of FBG, KW/BW, BUN, Cr, Upro and the expression of TGF-beta1 and IV-C proteins in renal tissue of diabetic rats with nephropathy. CONCLUSION: Berberine may protect renal function and slow down the progression of diabetic nephropathy in rats by suppressing the expression of TGF-beta1 and IV-C proteins in renal tissue.

[Effect of compound Rhizoma Coptidis capsule on expression of transforming growth factor-beta1 and type IV collagen proteins in renal tissue of diabetic rats with nephropathy].

OBJECTIVE: To explore the effect and mechanism of compound Rhizoma Coptidis capsule (CRCC) on diabetic nephropathy in experimental rats. METHOD: The rat model of early diabetic nephropathy was induced by injection of streptozotocin (STZ). The rats were divided into 6 groups: normal control group, model group, 3 CRCC treatment groups and XKW treatment group. The fasting blood glucose (FBG), blood urea nitrogen (BUN), creatinine (Cr), insulin (Ins) and urinary protein (Upro) were tested 30 days later. The expression of transforming growth factor-beta1 (TGF-beta1) and type IV collagen (IV-C) proteins and the pathological changes in renal tissue of diabetic rats with nephropathy were observed by optical micrography. RESULT: CRCC could reduce the levels of FBG, BUN, Cr, Upro and the expression of TGF-beta1 and IV-C proteins, and alleviate pathological lesion in renal tissue of diabetic rats with nephropathy. CONCLUSION: CRCC may protect the renal function and slow down the progression of diabetic nephropathy in rats by suppressing the expression of TGF-beta1 and IV-C proteins in renal tissue.

Effects and mechanisms of catechin for adjuvant arthritis in rats.

The present study was carried out to investigate the effects of catechin on adjuvant arthritis (AA) in the rat and its possible mechanisms of action. AA was induced by metatarsal footpad injection with complete Freund's adjuvant in male Sprague-Dawley rats. The secondary inflammatory reaction was evaluated through assessment of hind paw swelling, polyarthritis index, and pain response. Proliferation of synoviocytes and the activity of interleukin-1 were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Tumor necrosis factor-alpha, prostaglandin E(2) (PGE(2)), and cyclic adenosine monophosphate levels in synoviocytes were measured by radioimmunoassay. The PGE(2) receptor, EP(2), was analyzed by Western blot analysis. Intragastric administration of catechin (60 and 120 mg/kg) significantly suppressed secondary inflammatory paw swelling, pain response, and polyarthritis index. It also inhibited production of interleukin-1, tumor necrosis factor-alpha, and PGE(2) and increased cyclic adenosine monophosphate levels in rats with AA. In the immunoblot analysis, catechin could upregulate expression of EP(2) in the synoviocytes of rats with AA. The results showed that catechin reduced secondary inflammation in rats with AA; this outcome reflects its ability to mediate cAMP levels, upregulate expression of EP(2), and inhibit secretion of proinflammatory cytokines in rats with AA.

Effects of berberine on diabetes induced by alloxan and a high-fat/high-cholesterol diet in rats.

Berberine is the major active constituent of Rhizoma coptidis. The present study was carried out to investigate the effect of berberine on diabetes in rats and its possible mechanisms. Diabetes was induced by tail vein injection with alloxan in Wistar rats. The amount of alloxan administered was 55 mg/kg. Diabetic rats were fed with a high-cholesterol diet. The fasting blood glucose, total cholesterol (TC), triglyceride (TG) and low density lipoprotein-cholesterol (LDL-c), high density lipoprotein-cholesterol (HDL-c), nitric oxide (NO) levels in serum and malondialdehyde (MDA),superoxide dismutase (SOD),glutathione peroxidase (GSH-px) contents in heart tissue were assayed by spectrophotometry. Pancreas samples collected after 3 weeks of alloxan treatment were stained with hematoxylin-eosin (HE) and examined under a light microscope, and scored. Intragastric administration of berberine (100 and 200 mg/kg) significantly decreased fasting blood glucose levels, serum content of TC, TG, LDL-c, and effectively increased HDL-c, NO level in diabetic rats. Furthermore, berberine treatment significantly blocked the increase of MDA, increased SOD and GSH-px levels in diabetic rats. Histopathological scores showed that berberine had restored the damage of pancreas tissues in rats with diabetes mellitus. The results showed berberine significantly inhibited the progression of diabetes induced by alloxan, and the inhibitory effect of berberine on diabetes might be associated with its hypoglycemic effect, modulating lipids metabolic effects and its ability to scavenge free radical.