Cissus quadrangularis extract attenuates diabetic nephropathy by altering SIRT1/DNMT1 axis

Therapeutic potential of bark extracts from Macaranga denticulata on renal fibrosis in streptozotocin-induced diabetic rats

Macaranga denticulata (MD) bark is commonly utilized in traditional medicine for diabetes prevention and treatment. The bark extract of MD is rich in prenyl or farnesyl flavonoids and stilbenes, which possess antioxidant properties. Although data suggest the potential therapeutic benefits of the use of MD in treating diabetic nephropathy (DN), the precise mechanisms underlying MD-initiated protective effects against DN are not well understood. This study aimed to assess the renoprotective properties of MD extract by examining renofibrosis inhibition, oxidative stress, and inflammation utilizing streptozotocin-induced DN male Sprague - Dawley rats. Diabetic rats were intraperitoneally injected with streptozotocin (STZ) to induce diabetes. After 6 days, these rats were orally administered MD extract (200 mg/kg/day) or metformin (200 mg/kg/day) for 14 days. The administration of MD extract significantly lowered blood glucose levels, restored body weight, and reduced urine levels of various biomarkers associated with kidney functions. Histopathological analysis revealed protective effects in both kidneys and pancreas. Further, MD extract significantly restored abnormalities in advanced glycation end products, oxidative stress biomarkers, and proinflammatory cytokine levels in STZ-treated rats. MD extract markedly reduced renal fibrosis biomarker levels, indicating recovery from renal injury, and reversed dysregulation of sirtuins and claudin-1 in the kidneys of rats with STZ-induced diabetes. In conclusion, data demonstrated the renoprotective role of MD extract, indicating plant extract's ability to suppress oxidative stress and regulate proinflammatory pathways during pathological changes in diabetic nephropathy.

Diosgenin Improves Lipid Metabolism in Diabetic Nephropathy via Regulation of miR-148b-3p/DNMT1/FOXO1 Axis

BACKGROUND

The progression of diabetic nephropathy (DN) is closely associated with lipid accumulation. Diosgenin (Dio) plays a beneficial role in the lipid metabolism associated with multiple diseases. Thus, the mechanism underlying Dio's function in DN associated with aberrant lipid accumulation warrants further investigation.

METHODS

To model DN in vitro, HK-2 cells were treated with high glucose (HG) and palmitic acid. Cell viability was evaluated using MTT assay. The triglyceride (TG) content in HK-2 cells was measured using a commercial assay kit. The formation of lipid droplets in HK-2 cells was observed using Oil Red O staining. The expression levels of mRNA and protein were detected using RT-qPCR and Western blot, respectively. The DNA methylation of FOXO1 was assessed using MSP. The interaction between DNMT1 and the FOXO1 promoter was confirmed by ChIP assay.

RESULTS

Dio treatment reduced TG levels and lipid droplet formation in HK-2 cells co-treated with HG and palmitic acid. Simultaneously, the levels of miR-148b-3p and FOXO1 were increased by Dio, while Dio decreased the expression levels of DNMT1 and SREBP-2. Meanwhile, miR-148b-3p can bind to DNMT1, which in turn inhibits the expression of FOXO1 by mediating the DNA methylation of FOXO1. In addition, FOXO1 negatively regulates the expression of SREBP-2 by interacting with the SREBP-2 promoter. MiR-148b-3p inhibition or silencing of FOXO1 abolished the inhibitory effect of Dio on TG production and lipid droplet formation. This effect was further exacerbated by the downregulation of DNMT1. FOXO1 overexpression may counteract the promotive effects of miR-148b-3p inhibitor on lipid accumulation.

CONCLUSIONS

Dio treatment reduced TG production and lipid droplet formation in HK-2 cells during the progression of DN by modulating the miR-148b-3p/DNMT1/FOXO1/SREBP-2 axis. This finding provides new evidence supporting the therapeutic potential of Dio for DN.

DNMT1-Mediated the Downregulation of FOXF1 Promotes High Glucose-induced Podocyte Damage by Regulating the miR-342-3p/E2F1 Axis

Podocyte damage plays a crucial role in the occurrence and development of diabetic nephropathy (DN). Accumulating evidence suggests that dysregulation of transcription factors plays a crucial role in podocyte damage in DN. However, the biological functions and underlying mechanisms of most transcription factors in hyperglycemia-induced podocytes damage remain largely unknown. Through integrated analysis of data mining, bioinformatics, and RT-qPCR validation, we identified a critical transcription factor forkhead box F1 (FOXF1) implicated in DN progression. Moreover, we discovered that FOXF1 was extensively down-regulated in renal tissue and serum from DN patients as well as in high glucose (HG)-induced podocyte damage. Meanwhile, our findings showed that FOXF1 might be a viable diagnostic marker for DN patients. Functional experiments demonstrated that overexpression of FOXF1 strikingly enhanced proliferation, outstandingly suppressed apoptosis, and dramatically reduced inflammation and fibrosis in HG-induced podocytes damage. Mechanistically, we found that the downregulation of FOXF1 in HG-induced podocyte damage was caused by DNMT1 directly binding to FOXF1 promoter and mediating DNA hypermethylation to block FOXF1 transcriptional activity. Furthermore, we found that FOXF1 inhibited the transcriptional expression of miR-342-3p by binding to the promoter of miR-342, resulting in reduced sponge adsorption of miR-342-3p to E2F1, promoting the expression of E2F1, and thereby inhibiting HG-induced podocytes damage. In conclusion, our findings showed that blocking the FOXF1/miR-342-3p/E2F1 axis greatly alleviated HG-induced podocyte damage, which provided a fresh perspective on the pathogenesis and therapeutic strategies for DN patients.

Chinese herbal medicine for the treatment of diabetic nephropathy: From clinical evidence to potential mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is a typical chronic microvascular complication of diabetes, characterized by proteinuria and a gradual decline in renal function. At present, there are limited clinical interventions aimed at preventing the progression of DN to end-stage renal disease (ESRD). However, Chinese herbal medicine presents a distinct therapeutic approach that can be effectively combined with conventional Western medicine treatments to safeguard renal function. This combination holds considerable practical implications for the treatment of DN.

AIM OF THE STUDY

This review covers commonly used Chinese herbal remedies and decoctions applicable to various types of DN, and we summarize the role played by their active ingredients in the treatment of DN and their mechanisms, which includes how they might improve inflammation and metabolic abnormalities to provide new ideas to cope with the development of DN.

MATERIALS AND METHODS

With the keywords "diabetic nephropathy," "Chinese herbal medicine," "clinical effectiveness," and "bioactive components," we conducted an extensive literature search of several databases, including PubMed, Web of Science, CNKI, and Wanfang database, to discover studies on herbal formulas that were effective in slowing the progression of DN. The names of the plants covered in the review have been checked at MPNS (http://mpns.kew.org).

RESULTS

This review demonstrates the superior total clinical effective rate of combining Chinese herbal medicines with Western medicines over the use of Western medicines alone, as evidenced by summarizing the results of several clinical trials. Furthermore, the review highlights the nephroprotective effects of seven frequently used herbs exerting beneficial effects such as podocyte repair, anti-fibrosis of renal tissues, and regulation of glucose and lipid metabolism through multiple signaling pathways in the treatment of DN.

CONCLUSIONS

The potential of herbs in treating DN is evident from their excellent effectiveness and the ability of different herbs to target various symptoms of the condition. However, limitations arise from the deficiencies in interfacing with objective bioindicators, which hinder the integration of herbal therapies into modern medical practice. Further research is warranted to address these limitations and enhance the compatibility of herbal therapies with contemporary medical standards.

Correlation between peripheral blood α1-MG, DNMT1 expression, and the severity of diabetic nephropathy renal pathological damage

To explore the correlation between peripheral blood α1-microglobulin (α1-MG) and monocyte DNA methyltransferase 1 (DNMT1) expression and the severity of renal pathological damage in diabetic nephropathy (DN). The study group comprised 100 patients with DN who underwent treatment at our hospital from January 2022 to January 2023, while the control group consisted of 50 patients with uncomplicated diabetes. The relative expression levels of peripheral blood α1-MG and DNMT1 were compared between the 2 groups of patients. Additionally, the levels of vascular endothelial growth factor (VEGF) were measured, and the diagnostic value of DN was explored using ROC curves. Furthermore, the correlation between the aforementioned indicators and the severity of renal pathological damage in the patients of the study group was analyzed. Compared to the patients in the control group, the patients in the study group showed increased relative expression levels of peripheral blood α1-MG and DNMT1, as well as elevated levels of VEGF (P < .05). The diagnostic value of peripheral blood α1-MG, DNMT1 relative expression levels, and VEGF levels for DN was explored using ROC curves. The AUC values were 0.907, 0.923, and 0.936, respectively (P < .05). The relative expression levels of peripheral blood α1-MG, DNMT1, and VEGF levels in DN patients increase with the elevation of the interstitial fibrosis and tubular atrophy scoring (IFTA) score, showing a positive correlation with r-values of 0.651, 0.710, and 0.628, respectively (P < .05). The relative expression levels of peripheral blood α1-MG, DNMT1, and VEGF levels in DN patients increase with the elevation of the interstitial inflammation score, showing a positive correlation with r-values of 0.771, 0.633, and 0.678, respectively (P < .05). The relative expression levels of peripheral blood α1-MG, DNMT1, and VEGF levels in DN patients increase with the elevation of the glomerular grading, showing a positive correlation with r-values of 0.714, 0.609, and 0.677, respectively (P < .05). The expression levels of peripheral blood α1-MG, DNMT1, and VEGF are significantly elevated in patients with DN. These levels show a positive correlation with the IFTA score, interstitial inflammation score, and glomerular grading, contributing to the diagnosis and assessment of DN.

Simultaneous Estimation of Quercetin and trans-Resveratrol in Cissus quadrangularis Extract in Rat Serum Using Validated LC-MS/MS Method: Application to Pharmacokinetic and Stability Studies

Cissus quadrangularis is a nutrient-rich plant with a history of use in traditional medicine. It boasts a diverse range of polyphenols, including quercetin, resveratrol, β-sitosterol, myricetin, and other compounds. We developed and validated a sensitive LC-MS/MS method to quantify quercetin and t-res biomarkers in rat serum and applied this method to pharmacokinetic and stability studies. The mass spectrometer was set to negative ionization mode for the quantification of quercetin and t-res. Phenomenex Luna (C18(2), 100 A, 75 × 4.6 mm, 3 µ) column was utilized to separate the analytes using an isocratic mobile phase consisting of methanol and 0.1% formic acid in water (82:18). Validation of the method was performed using various parameters, including linearity, specificity, accuracy, stability, intra-day, inter-day precision, and the matrix effect. There was no observed significant endogenous interference from the blank serum. The analysis was completed within 5.0 min for each run, and the lower limit of quantification was 5 ng/mL. The calibration curves showed a linear range with a high correlation coefficient (r² > 0.99). The precision for intra- and inter-day assays showed relative standard deviations from 3.32% to 8.86% and 4.35% to 9.61%, respectively. The analytes in rat serum were stable during bench-top, freeze-thaw, and autosampler (-4 °C) stability studies. After oral administration, the analytes showed rapid absorption but underwent metabolism in rat liver microsomes despite being stable in simulated gastric and intestinal fluids. Intragastric administration resulted in higher absorption of quercetin and t-res, with greater C_max, shorter half-life, and improved elimination. No prior research has been conducted on the oral pharmacokinetics and stability of anti-diabetic compounds in the Ethanolic extract of Cissus quadrangularis EECQ, making this the first report. Our findings can provide the knowledge of EECQ's bioanalysis and pharmacokinetic properties which is useful for future clinical trials.

"Multiomics" Analyses Combined with Systems Pharmacology Reveal the Renoprotection of Mangiferin Monosodium Salt in Rats with Diabetic Nephropathy: Focus on Improvements in Renal Ferroptosis, Renal Inflammation, and Podocyte Insulin Resistance

We explored the protection of mangiferin monosodium salt (MGM) on kidney injury in rats with streptozotocin (STZ)-induced diabetic nephropathy (DN) by "multiomics" analysis combined with systems pharmacology, with a specific focus on ferroptosis, inflammation, and podocyte insulin resistance (IR) signaling events in kidneys. MGM treatment afforded renoprotective effects on rats with STZ-induced DN by alleviating systemic IR-induced renal inflammation and podocyte IR. These mechanisms were correlated mainly with the MGM treatment-induced inhibition of the mitogen-activated protein kinase/nuclear factor-kappa B axis and activation of the phosphorylated insulin receptor substrate 1(Tyr608)/phosphorylated phosphatidylinositol 3-kinase/phosphorylated protein kinase B axis in the kidneys of DN rats. MGM had an ameliorative function in renal ferroptosis in rats with STZ-induced DN by upregulating mevalonate-mediated antioxidant capacities (glutathione peroxidase 4 and ferroptosis suppressor protein 1/coenzyme Q10 axis) and weakening acyl-CoA synthetase long-chain family member 4-mediated proferroptotic generation of lipid drivers in kidneys. MGM may be a promising alternative strategy for the treatment of DN.

Evaluation of mutagenic, cytotoxic, mitochondrial dysfunction, apoptotic activity, and acute toxicity of ethanolic extract of Cissus quadrangularis

Recent studies have focused on exploring the efficacy of Cissus quadrangularis extract (EECQ) against various metabolic disorders involving the liver as the prime target organ, suggesting a considerable threat of hepatotoxicity in the person encountering it. Consequently, the current study was aimed to unravel the mutagenic, cytotoxic, mitochondrial dysfunction, apoptotic activity in HepG2 cells, and acute toxicity of EECQ. MTT, SRB, trypan blue dye exclusion, and lactate dehydrogenase (LDH) assay were performed in HepG2 cell lines to determine the cytotoxicity of the extract. The mutagenic potential was determined by the Ames test using various strains of Salmonella typhimurium. Acute toxicity was done at a dose of 2000 mg/kg in Sprague Dawley rats. MTT and SRB cytotoxicity assays demonstrated dose-dependent cytotoxicity of extract. The three highest noncytotoxic doses from the above assay, investigated by trypan blue dye exclusion and LDH assay, did not reveal cytotoxicity. Besides, mitochondrial dysfunction was determined by measuring cellular and mitochondrial ROS, ATP, NAD, mitochondrial membrane potential, Bax/Bcl2 ratio, mitochondrial and cytoplasmic cytochrome c, and apoptosis-inducing factor, were found to be equivalent in both extract exposed and unexposed cells. Moreover, the apoptotic cell morphology and the expression of pro-apoptotic mRNAs and proteins were equivalent in both the group. In acute toxicity, EECQ in rats did not cause any significant change in body weight, liver index, and liver function test. All-encompassing, the present study unraveled that EECQ is not mutagenic, cytotoxic, nor apoptotic in human hepatic cells, as well as neither acute toxicity.

Lagerstroemia speciosa Ameliorated Blood Pressure in LNAME Induced Hypertension in Experimental Rats through NO/cGMP and Oxidative Stress Modulation

Cardiovascular disease is the primary reason for chronic heart diseases and mortality worldwide. Hypertension (HTN) is the utmost dominant risk factor for the evolution of several diseases. Herbal medicines, traditional medicinal herbs, and their extracts are widely utilized to treat and monitor HTN. Herbal components have been shown to help relax arteries and lower oxidative stress. The current study assesses the probable role of herbal plant extract Lagerstroemia speciosa (LS) in the LNAME induced HTN in rats. LNAME (50 mg/100 mL) in drinkable water was given to rats for five weeks. There was a significant upsurge in LNAME-treated hypertensive rats' blood pressure (BP). On treatment with LS, it ameliorates blood pressure. Further, LS also improved body weight, reduced heart weight, and heart hypertrophy. The NO/cGMP concentration was lowered along with a substantial upsurge in the level of glutathione and a decline in MDA level. The LS extract also reduced the inflammatory cytokine markers in the systemic circulation. In conclusion, thus, the extract of LS treatment can efficiently alleviate the BP, oxidative stress markers, and inflammation and improve NO/cGMP concentration in LNAME induced HTN in rats.

Cissus quadrangularis extract mitigates diabetic cardiomyopathy by inhibiting RAAS activation, inflammation, and oxidative stress

IntroductionDiabetic cardiomyopathy (DCM) is an age-related disease, and its progression is accompanied by hyperglycemia, cardiac dysfunction, and myocardial structural and functional abnormalities. Cissus quadrangularis, a traditional medicinal plant, contains polyphenols, flavonoids, phytosterols, carbohydrates, and ascorbic acid. It is used to treat osteoporosis, asthma, haemorrhoids, and menstrual disorders. In the current research, we have investigated the effect of ethanolic extract of C. quadrangularis (EECQ) against a high-fat diet (HFD)/streptozotocin-induced DCM by estimating cardiac biomarkers, inflammatory markers and ROS production.Material and methodsRats were fed with an HFD for 12 weeks, followed by single-shot low-dose streptozotocin (35mg/kg; i.p.). The treatment was performed by EECQ (200 mg/kg/day, orally) for six weeks. ResultsThe extract EECQ improves glucose, insulin tolerance tests, and hypercholesteremia. DCM is characterized by cardiac dysfunction, cardiac biomarkers CKMB, and LDH, which were attenuated by the EECQ treatment. The hypertrophic biomarker ANP, BNP expression and cardiomyocyte surface area were decreased by EECQ. Moreover, EECQ also alleviated the biomarkers Angiotensin II and renin level. EECQ also reduced oxidative stress, ROS production and cardiac inflammation.ConclusionThus, these findings suggested that EECQ could be used as a possible therapeutic regiment to treat DCM.

Bibliometric Study of Trends in the Diabetic Nephropathy Research Space from 2016 to 2020

Background

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes mellitus (DM), but no bibliometric studies pertaining to DN have been published within the last 5 years.

Objectives

Most prior studies have focused on specific problems in the DN field. This study attempts to sort out and visualize the knowledge framework in this research space from a holistic and highly generalized perspective. Readers can quickly understand and master the knowledge regarding DN research conducted from 2016 to 2020, in addition to predicting future research hotspots and possible directions for development in this field in a comprehensive and scientifically valid manner.

Methods

Literature information, discourse matrices, and co-occurrence matrices were generated using BICOMB. gCLUTO was used for biclustering analyses and visualization. Strategic diagrams were generated using GraphPad Prism 5. The social network analysis (SNA) was analyzed and plotted using Ucinet 6.0 and Netdraw.

Results

In total, 55 high-frequency MeSH terms/MeSH subheadings were selected and grouped into 5 clusters in a biclustering analysis. These analyses revealed that extensive studies of the etiology, diagnosis, and treatment of DN have been conducted over the last 5 years, while further research regarding DN-related single nucleotide polymorphisms, miRNAs, and signal transduction are warranted as these research areas remain relatively immature.

Conclusion

Together, these results outline a robust knowledge structure pertaining to the field of DN-related research over the last 5 years, providing a valuable resource for readers by enabling the easy comprehension of relevant information. In addition, this analysis highlights predicted DN-related research directions and hotspots.

Polyphenolic-rich Cissus quadrangularis extract ameliorates insulin resistance by activating AdipoR1 in peri-/post-menopausal rats

Insulin resistance (IR) is a significant complication in menopausal women, which predisposes them to cardiovascular disorder, obesity, and diabetes. Cissus quadrangularis is a polyphenolic plant rich in nutrients and is used as an edible vegetable in Nigeria. Previously, we investigated that C. quadrangularis extract (EECQ) treatment ameliorates IR, hyperlipidemia, and overweight in diabetic rats. Accordingly, in the current study, we further evaluated the adiponectin mimetic activity of EECQ in peri-/post-menopausal rats. Perimenopause was induced by High-fat diet/4-vinylcyclohexenediepoxide/(HFD-VCD), while postmenopause was by HFD/bilateral ovariectomy (HFD-OVX). Both the menopausal rats demonstrated an abnormal level of sex hormones, IR, hyperlipidemia, increased fat mass, and abnormal weight gain. Nevertheless, EECQ treated group revealed protection from these untoward complications. Furthermore, the docking score of major constituents of EECQ on adiponectin receptor 1 (AdipoR1) depicted a strong binding affinity, which was comparable to the ligand adipoRon. Besides, AdipoR1 expression determined by RT-PCR, Western blotting, and immunohistochemistry was downregulated in peri-/post-menopausal rats. Similarly, the expression of AdipoR1 downstream marker APPL1 and insulin sensitivity markers, including IRS1, Akt1, and GLUT4, were also dysregulated in menopausal rats. However, EECQ treated rats manifested restoration of normal expression of APPL1, IRS1, Akt1, and GLUT4 by upregulating AdipoR1. Altogether, the current study promulgated the adiponectin mimetic activity of EECQ, which is substantial to mitigate IR in menopausal conditions.

Silencing of PFKFB3 protects podocytes against high glucose‑induced injury by inducing autophagy

Diabetic nephropathy (DN) is a diabetic complication that threatens the health of patients with diabetes. In addition, podocyte injury can lead to the occurrence of DN. The protein 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) may be associated with diabetes; however, the effects of PFKFB3 knockdown by small interfering (si)RNA on the growth of podocytes remains unknown. To investigate the mechanism by which PFKFB3 mediates podocyte injury, MPC5 mouse podocyte cells were treated with high-glucose (HG), and cell viability and apoptosis were examined by Cell Counting Kit-8 assay and flow cytometry, respectively. In addition, the expression of autophagy-related proteins were measured using western blot analysis and immunofluorescence staining. Cell migration was investigated using a Transwell assay and phalloidin staining was performed to observe the cytoskeleton. The results revealed that silencing of PFKFB3 significantly promoted MPC5 cell viability and inhibited apoptosis. In addition, the migration of the MPC5 cells was notably downregulated by siPFKFB3. Moreover, PFKFB3 silencing notably reversed the HG-induced decrease in oxygen consumption rate, and the HG-induced increase in extracellular acidification rate was rescued by PFKFB3 siRNA. Furthermore, silencing of PFKFB3 induced autophagy in HG-treated podocytes through inactivating phosphorylated (p-)mTOR, p-AMPKα, LC3 and sirtuin 1, and activating p62. In conclusion, silencing of PFKFB3 may protect podocytes from HG-induced injury by inducing autophagy. Therefore, PFKFB3 may serve as a potential target for treatment of DN.