Tangshen Formula Attenuates Diabetic Nephropathy by Promoting ABCA1-Mediated Renal Cholesterol Efflux in db/db Mice

Dysregulation of lipid metabolism in chronic kidney disease and the role of natural products

Dysregulation of lipid metabolism plays a key role in the onset and progression of CKD, and a thorough understanding of its regulatory mechanisms is essential for the development of effective treatments. In recent years, an increasing number of studies have focused on the pharmacological activities of natural products and their application in the treatment of chronic diseases. Natural products, including plant extracts and bioactive compounds, have been shown to exert anti-inflammatory, antioxidant, antifibrosis, and anti-apoptotic effects through various signaling pathways in the treatment of CKD. Many natural products have been shown to target dysregulated lipid metabolism through various signaling pathways. This review summarizes the key regulatory factors and signaling pathways involved in the dysregulation of lipid metabolism in chronic kidney disease (CKD), highlighting their importance as potential therapeutic targets. Recently published research on the potential therapeutic benefits of natural products for the treatment of CKD was described. These studies have revealed the multi-target role of natural products in the regulation of lipid metabolism. Natural products show great potential in targeting lipid metabolism-related pathways, offering a novel research direction for the treatment of CKD while providing a scientific basis and experimental support for the development of new treatment strategies.

GLP-1RA improves diabetic renal injury by alleviating glomerular endothelial cells pyrotosis via RXRα/circ8411/miR-23a-5p/ABCA1 pathway

BACKGROUND

Lipotoxicity has been implicated in diabetic kidney disease (DKD). However, the role of high glucose levels in DKD and the underlying renal protective mechanisms of GLP-1 receptor agonists (GLP-1RAs) remain unclear.

METHODS

To investigate cholesterol accumulation, pyroptosis in glomerular endothelial cells (GEnCs), and the renal protective mechanisms of GLP-1RAs, we used various techniques, including RT-qPCR, Oil Red O staining, Western blotting, lactate dehydrogenase (LDH) activity assays, circRNA microarrays, bioinformatics analysis, gain and loss-of-function experiments, rescue experiments, and luciferase assays. Additionally, in vivo experiments were conducted using C57BL/6J and ApoE-deficient (ApoE-/-) mice.

RESULTS

GEnCs exposed to high glucose exhibited reduced cholesterol efflux, which was accompanied by downregulation of ATP-binding cassette transporter A1 (ABCA1) expression, cholesterol accumulation, and pyroptosis. Circ8411 was identified as a regulator of ABCA1, inhibiting miR-23a-5p through its binding to the 3'UTR. Additionally, higher glucose levels decreased circ8411 expression by inhibiting RXRα. GLP-1RAs effectively reduced cholesterol accumulation and cell pyroptosis by targeting the RXRα/circ8411/miR-23a-5p/ABCA1 pathway. In diabetic ApoE-/- mice, renal structure and function were impaired, with resulted in increased cholesterol accumulation and pyroptosis; however, GLP-1RAs treatment reversed these detrimental changes.

CONCLUSIONS

These findings suggest that the RXRα/circ8411/miR-23a-5p/ABCA1 pathway mediates the contribution of high glucose to lipotoxic renal injury. Targeting this pathway may represent a potential therapeutic strategy for patients with DKD and hypercholesterolemia. Moreover, GLP-1RAs may provide renal protective effects by activating this pathway.

Analysis of Single Nucleotide Polymorphisms of Liver X Receptor Alpha (LXR-α) Gene in Diabetic Kidney Disease

Introduction Genetic factors significantly contribute to the progression of diabetic kidney disease (DKD), which is one of the world's most common causes of chronic kidney disease (CKD). Inflammation, glucose homeostasis, and lipid metabolism are all significantly influenced by the liver X receptor alpha (LXR-α) gene. Single nucleotide polymorphisms in the liver X receptor alpha gene may result in the altered function of the gene, making the individual susceptible to DKD. The purpose of this article is to examine the frequency of expression of single nucleotide polymorphisms (SNPs) in exon 7 of the LXR-α gene in people with type 2 diabetes (T2DM) and DKD. Gaining an understanding of these genetic differences could improve risk assessment and therapy approaches while providing fresh perspectives on the molecular mechanisms underlying DKD. Aims and objectives To identify specific SNPs in the LXR-α gene in T2DM and DKD patients. Methods The study was conducted between May 2022 and May 2023 and it involved 120 T2DM and 120 DKD patients. All the clinical history of the study participants were recorded. Blood samples were collected from the participants and genomic DNA was isolated and was followed by polymerase chain reaction (PCR) using exon 7 specified primers of LXR-α gene. To find mutations in the LXR-α gene, the PCR products were subsequently analyzed using the capillary-based Sanger sequencing technique. Results A total of seven SNPs were detected in T2DM patients, and 20 SNPs were detected in DKD patients. SNP rs7120118 was found with the highest frequency of 100 (83.33%) in T2DM patients and 80 (66.66%) in DKD patients. SNP rs1956299169 was found to have the second highest frequency of 60 (50%) among T2DM patients and SNP rs1252683195 was found to have a frequency of 20 (16.7%). Other common SNPs were rs1956299169, with 40 (33.33%) in DKD and 60 (50%) in T2DM, and rs12574081, with 20 (16.71%) in T2DM and 10 (8.33%) in T2DM. Conclusion The study detects the highest and the most common SNP rs7120118, which may be associated with T2DM and DKD. Thereby, it helps to conduct further association studies with larger populations and to diagnose the disease.

Morroniside attenuates podocytes lipid deposition in diabetic nephropathy: A network pharmacology, molecular docking and experimental validation study

BACKGROUND

Dysregulation of lipid metabolism is a key factor influencing the progression of diabetic nephropathy (DN). Morroniside (MOR) is a major active compound isolated from the traditional Chinese herb Cornus officinalis, our previous research found that it can improve the lipid deposition of renal tubular epithelial cells. The purpose of this study is to explore whether MOR can improve podocyte lipid deposition and its mechanism of reducing DN.

METHODS

Initially, we used network pharmacology and bioinformatics techniques to predict the relationship between renal lipid metabolism of MOR and DN. Subsequently, the binding activity of MOR with lipid-related proteins was studied by molecular docking to determine how MOR acts through these proteins. After determining the target of MOR, animal experiments and cell tests were carried out to verify it.

RESULTS

Using network pharmacology, bioinformatics, and molecular docking, target proteins for MOR treatment of DN were predicted and screened, including PGC-1α, LXRs, ABCA1, PPARY, CD36, and nephrin. It is particularly noted that MOR effectively binds to PGC-1α, while LXRs, ABCA1, PPARY and CD36 are downstream molecules of PGC-1α. Silencing the PGC-1α gene significantly reduced the therapeutic effects of MOR. Conversely, in groups without PGC-1α knockdown, MOR was able to increase the expression levels of PGC-1α and influence the expression of downstream proteins. Furthermore, through in vivo and in vitro experiments, utilizing techniques such as lipid droplet staining, PAS, MASSON staining, immunofluorescence, and Western blot, we found that MOR effectively elevated the expression levels of the podocyte protein nephrin and lipid metabolism-regulating proteins PGC-1α, PPARY, and ABCA1, while significantly inhibiting the expression of the lipid accumulation promoter CD36.

CONCLUSION

MOR can regulate the cholesterol efflux in podocytes via the PGC-1α/LXRs/ABCA1 signaling pathway, and control cholesterol intake via the PGC-1α/PPARY/CD36 signaling pathway, thereby ameliorating lipid deposition in DN.

Mechanisms of hepatic and renal injury in lipid metabolism disorders in metabolic syndrome

Metabolic syndrome (MetS) is a group of metabolic abnormalities that identifies people at risk for diabetes and cardiovascular disease. MetS is characterized by lipid disorders, and non-alcoholic fatty liver disease (NAFLD) and diabetic kidney disease (DKD) are thought to be the common hepatic and renal manifestations of MetS following abnormal lipid metabolism. This paper reviews the molecular mechanisms of lipid deposition in NAFLD and DKD, highlighting the commonalities and differences in lipid metabolic pathways in NAFLD and DKD. Hepatic and renal steatosis is the result of lipid acquisition exceeding lipid processing, i.e., fatty acid uptake and lipid regeneration exceed fatty acid oxidation and export. This process is directly regulated by the interactions of nuclear receptors, transporter proteins and transcription factors, whereas pathways such as oxidative stress, autophagy, cellular pyroptosis and gut flora are also key regulatory hubs for lipid metabolic homeostasis but act slightly differently in the liver and kidney. Such insights based on liver-kidney similarities and differences offer potential options for improved treatment.

PGC1-α in diabetic kidney disease: unraveling renoprotection and molecular mechanisms

Mitochondrial dysfunction represents a pivotal aspect of the pathogenesis and progression of diabetic kidney disease (DKD). Central to the orchestration of mitochondrial biogenesis is the peroxisome proliferator-activated receptor γ coactivator 1-α (PGC1-α), a master regulator with a profound impact on mitochondrial function. In the context of DKD, PGC1-α exhibits significant downregulation within intrinsic renal cells, precipitating a cascade of deleterious events. This includes a reduction in mitochondrial biogenesis, heightened levels of mitochondrial oxidative stress, perturbed mitochondrial dynamics, and dysregulated mitophagy. Concurrently, structural and functional abnormalities within the mitochondrial network ensue. In stark contrast, the sustained expression of PGC1-α emerges as a beacon of hope in maintaining mitochondrial homeostasis within intrinsic renal cells, ultimately demonstrating an impressive renoprotective potential in animal models afflicted with DKD. This comprehensive review aims to delve into the recent advancements in our understanding of the renoprotective properties wielded by PGC1-α. Specifically, it elucidates the potential molecular mechanisms underlying PGC1-α's protective effects within renal tubular epithelial cells, podocytes, glomerular endothelial cells, and mesangial cells in the context of DKD. By shedding light on these intricate mechanisms, we aspire to provide valuable insights that may pave the way for innovative therapeutic interventions in the management of DKD.

Designing nanodiscs as versatile platforms for on-demand therapy

Nowadays, there has been an increasing utilization of nanomedicines for disease treatment. Nanodiscs (NDs) have emerged as a novel platform technology that garners significant attention in biomedical research and drug discovery. NDs are nanoscale phospholipid bilayer discs capable of incorporating membrane proteins and lipids within a native-like environment. They are assembled using amphiphilic biomacromolecular materials, such as apolipoprotein A1 or membrane scaffold proteins (MSPs), peptides, and styrene-maleic acid polymers (SMAs). NDs possess well-defined sizes and shapes, offering a stable, homogeneous, and biologically relevant environment for studying membrane proteins and lipids. Their unique properties have made them highly desirable for diverse applications, including cancer immunotherapy, vaccine development, antibacterial and antiviral therapy, and treating Alzheimer's disease (AD) and diabetes-related conditions. This review discusses the classifications, advantages, and applications of NDs in disease therapy.

Effect of Tangshen formula on the remodeling of small intestine and colon in Zucker diabetic fatty rats

Background and aim

Previous study have demonstrated that Tangshen Formula (TSF) could attenuate colonic histomorphological remodeling in the diabetic rat model induced by high fat diet plus low dosage streptozotocin (STZ). However, it is not clear whether TSF has same effect on small intestine and the effect on biomechanical properties of bowel. The aim of this study is to investigate the effect of TSF on histomorphological and biomechanical remodeling of small intestine and colon by using Zucker Diabetic Fatty (ZDF) Rat model.

Materials and methods

ZDF rats (obese fa/fa) with blood glucose higher than 11.7 mmol/L were divided into ZDF group (diabetic control group) and ZDF + TSF group (TSF treatment group), the later were intragastrically administered TSF. The ZDF rats (lean fa/+) were served as normal control (ZL) group. The rats in the ZL and ZDF groups were administered with saline. The experimental period covered from 8 weeks to 24 weeks. At the end of experiment, the ileal and colonic segments were studied in vitro. The histomorphometry and biomechanical parameters were measured.

Results

Compared with ZL group histomorphologically, the wet weight per unit length, wall thickness, wall area and fractions of total and type I and type III collagen in different layers for both ileum and colon increased in ZDF group. Those increasing parameters were partially inhibited in ZDF + TSF group. Compared with ZL group biomechanically, ZDF and ZDF + TSF groups had smaller opening angle and residual strain in ileum, and bigger opening angle and residual strain in colon. Whereas the wall became softer in circumferential direction and stiffer in longitudinal direction for both ileum and colon. However, no difference of biomechanical parameters was found between ZDF and ZDF + TSF groups.

Conclusion

The histomorphological and biomechanical remodeling of ileum and colon were happened in ZDF rats （obese fa/fa）. TSF could partly attenuate ileal and colonic histomorphological remodeling rather than biomechanical remodeling.

ABCA1 deficiency-mediated glomerular cholesterol accumulation exacerbates glomerular endothelial injury and dysfunction in diabetic kidney disease

BACKGROUND

Hyperglycemia and dyslipidemia are two major characteristics of diabetes. In this study, the effects of glomerular cholesterol accumulation primarily due to ABCA1 deficiency on glomerular endothelial injury in diabetic kidney disease (DKD) and the possible mechanisms were investigated.

METHODS

The effects of ABCA1 deficiency on glomerular lipid deposition and kidney injury were examined in a type 2 diabetic mouse model with ABCA1 deficiency in glomerular endothelial cells (DM-ABCA1-/- mice) and human renal glomerular endothelial cells (HRGECs) cultured in high glucose and high cholesterol conditions, which simulated type 2 diabetes in vitro.

RESULTS

ABCA1 deficiency in glomerular endothelial cells exacerbated renal lipid deposition and kidney injuries in type 2 diabetic mice and manifested as increased creatinine levels, more severe proteinuria, mesangial matrix expansion and fusion of foot processes, and more pronounced renal inflammatory injury and cell death. In HRGECs cultured under high glucose and high cholesterol conditions, ABCA1 deficiency increased the deposition of cellular cholesterol, contributed to inflammation and apoptosis, damaged the endothelial glycocalyx barrier, and induced endoplasmic reticulum stress (ERS). Conversely, ABCA1 overexpression enhancing cholesterol efflux or inhibition of ERS in vitro, significantly protected against glomerular endothelial injury stimulated by high glucose and high cholesterol.

CONCLUSIONS

These findings establish a pathogenic role of ABCA1 deficiency in glomerular endothelium injury and dysfunction and imply that ABCA1 may represent a potential effective therapeutic target for early diabetic kidney disease.

Therapeutic mechanism and clinical application of Chinese herbal medicine against diabetic kidney disease

Diabetic kidney disease (DKD) is the major complications of type 1 and 2 diabetes, and is the predominant cause of chronic kidney disease and end-stage renal disease. The treatment of DKD normally consists of controlling blood glucose and improving kidney function. The blockade of renin-angiotensin-aldosterone system and the inhibition of sodium glucose cotransporter 2 (SGLT2) have become the first-line therapy of DKD, but such treatments have been difficult to effectively block continuous kidney function decline, eventually resulting in kidney failure and cardiovascular comorbidities. The complex mechanism of DKD highlights the importance of multiple therapeutic targets in treatment. Chinese herbal medicine (active compound, extract and formula) synergistically improves metabolism regulation, suppresses oxidative stress and inflammation, inhibits mitochondrial dysfunction, and regulates gut microbiota and related metabolism via modulating GLP-receptor, SGLT2, Sirt1/AMPK, AGE/RAGE, NF-κB, Nrf2, NLRP3, PGC-1α, and PINK1/Parkin pathways. Clinical trials prove the reliable evidences for Chinese herbal medicine against DKD, but more efforts are still needed to ensure the efficacy and safety of Chinese herbal medicine. Additionally, the ideal combined therapy of Chinese herbal medicine and conventional medicine normally yields more favorable benefits on DKD treatment, laying the foundation for novel strategies to treat DKD.

Beneficial effects of procyanidin B2 on adriamycin-induced nephrotic syndrome mice: the multi-action mechanism for ameliorating glomerular permselectivity injury

Despite considerable advances in prevention, diagnosis, and therapy, nephrotic syndrome (NS) remains a significant cause of high morbidity and mortality globally. As a result, there is an urgent need to identify novel effective preventative and therapeutic agents for NS. NS is implicated in glomerular permselectivity injury, which can be attributed to oxidative distress, inflammation, lipid nephrotoxicity, podocyte apoptosis, autophagy dysfunction, and slit diaphragm (SLD) dysfunction. In addition to its well-documented antioxidant potency, procyanidin B2 (PB2) may exhibit pleiotropic effects by targeting various canonical signaling events, such as NF-κB, PPARs, PI3K/Akt, mTOR, and the caspase family. As a result, PB2 may be a promising therapeutic target against NS. To test this hypothesis, we established an Adriamycin (ADR)-induced NS mouse model to evaluate the pleiotropic renoprotective effects of PB2 on NS. Here, we demonstrated that PB2 improves podocyte injury via inhibition of NOX4/ROS and Hsp90/NF-κB to exhibit antioxidant and anti-inflammatory potency, respectively. We also show that PB2 indirectly activates the PI3K/Akt axis by regulating SLD protein levels, resulting in normalized podocyte apoptosis and autophagy function. Further, loss of albumin (ALB) induces lipid nephrotoxicity, which we found to be alleviated by PB2 via activation of PPARα/β-mediated lipid homeostasis and the cholesterol efflux axis. Interestingly, our results also suggested that PB2 reduces electrolyte abnormalities and edema. In addition, PB2 may contribute protective effects against trace element dys-homeostasis, which, through alleviating serum ALB loss, leads to a protective effect on glomerular permselectivity injury. Taken together, our results reveal that the identified mechanisms of PB2 on NS are multifactorial and involve inhibition of oxidative distress and inflammatory responses, as well as improvements in podocyte apoptosis and autophagy dysfunction, amelioration of lipid nephrotoxicity, and modulation of electrolyte abnormalities and edema. Thus, we provide a theoretical basis for the clinical application of PB2 against NS.

Nanodisc delivery of liver X receptor agonist for the treatment of diabetic nephropathy

Dyslipidemia is recognized to be an important contributor to the progression of diabetic nephropathy (DN), leading to lipoprotein dysregulation, excessive mesangium expansion as well as inflammation in the glomeruli. Thus, dual targeting of abnormal cholesterol metabolism and inflammatory responses of mesangial cells represents an alternative approach for DN treatment. Herein, we sought to develop a renal-targeting therapeutic strategy for diabetic nephropathy by modifying synthetic high-density lipoprotein (sHDL) nanodiscs with a kidney targeting ligand (KT peptide) and encapsulating a liver X receptor (LXR) agonist in the modified sHDL. LXR agonists delivered by sHDL can facilitate the removal of excessive lipids from mesangial cells, ameliorate inflammation and restore normal renal function. Overall, our data suggests that our optimized KT-targeted sHDL/TO nanodiscs (KT-sHDL/TO) generate potent therapeutic efficacy not only by more efficient cholesterol efflux, but also by suppressing mesangial cell proliferation. Most importantly, in a DN murine model, KT-sHDL/TO ameliorated dyslipidemia and inflammation superior to blank sHDL and non-targeting sHDL/TO formulations, showing promise for future clinical translation in DN treatment.

Captopril and Spironolactone Can Attenuate Diabetic Nephropathy in Wistar Rats by Targeting ABCA1 and microRNA-33

Background:

Nephropathy diabetes is one of the important causes of death and a more prevalent cause of end-stage renal disease.

Objective:

The present study investigated the effect of applying spironolactone and captopril and their combination on some renal performance indices and cholesterol-efflux-related gene expression in nephropathy diabetic rats.

Methods:

Intraperitoneal injection of streptozotocin was used to induce diabetes in rats. FBS, creatinine, and BUN were assayed using the calorimetry technique; also, urine microalbumin was assayed by ELISA. Hepatic gene expressions of ABCA1, ABCG1, and miR-33 were evaluated by the real-time PCR method.

Results:

FBS levels in the captopril-treated group were significantly decreased compared with the untreated diabetic group. BUN levels of treated groups with captopril and a combination of captopril + spironolactone were significantly increased. GFR of both treated diabetic groups with captopril and spironolactone was significantly lower than an untreated diabetic group. ABCA1 gene expression in hepatic cells of the combination of spironolactone + captopril treated group was significantly increased compared to other treated and untreated diabetic groups. The hepatic expression of the ABCG1 gene in the treated and untreated diabetic groups was significantly lower than in the control group. Treatment of the diabetic group with only combination therapy decreased the hepatic gene expression of miR-33 significantly.

Conclusion:

Obtained results suggest that S+C combination therapy can improve nephropathy and diabetes disorders by targeting the ABCA1 and miR-33 gene expression. It is suggested miR-33 and ABCA1 genes evaluation could be a new therapeutic strategy for nephropathy diabetes remediation.

UPLC-MS/MS method for the determination of the herb composition of Tangshen formula and the in vivo pharmacokinetics of its metabolites in rat plasma

INTRODUCTION

Tangshen formula (TSF) is a traditional Chinese medicine composed of seven medicinal herbs including Astragalus membranaceus, Rehmannia glutinosa Libosch, Citrus aurantium L., etc. which is used to treat diabetic nephropathy III, IV qi and yin deficiency and stasis syndrome. Most of the studies on TSF are pharmacological and pharmacodynamic experiments. There are few basic studies on its chemical substances, and the effective constituents are not clear.

OBJECTIVE

To analyse the main chemical components of TSF and the absorbed components in rat plasma following oral administration based on liquid chromatography tandem mass spectrometry (LC-MS/MS). Moreover, providing a rapid and valid analytical strategy for simultaneous determination of six components in rat plasma and use it in pharmacokinetic studies.

RESULTS

A total of 132 components were identified in TSF, and 44 components were identified in rat plasma after oral TSF, 35 of which were prototype components and nine were metabolic components. A sensitive and reliable LC-MS/MS method was developed for simultaneous determination of six components in rat plasma. The intra-day and inter-day precision relative standard deviation (RSD) was lower than 15%; the accuracy of low, medium and high concentrations ranged from 80% to 120%. The recovery met the requirements and the RSD of the recoveries was less than 15%.

CONCLUSION

A total of 132 components were identified in TSF. The LC-MS/MS quantitative method for the simultaneous determination of morroniside, loganin, notoginsenoside R₁ , ginsenoside Re, ginsenoside Rb₁ and astragaloside IV in rat plasma was established for the first time. The pharmacokinetic parameters are clarified, which can guide the clinical medication of TSF.

A novel and comprehensive strategy for quality control in complex Chinese medicine formula using UHPLC-Q-Orbitrap HRMS and UHPLC-MS/MS combined with network pharmacology analysis: Take Tangshen formula as an example

The quality control of Chinese herbal medicines (CHM) is a key concern on the modernization and globalization. However, it is still a difficult task due to its multi-component, multi-target, multi-pathways. This study aims to provide a novel and comprehensive strategy for quality control in complex Chinese medicines (CHM) formulas by UHPLC-Q-Orbitrap HRMS and UHPLC-MS/MS combined with network pharmacology analysis. Tangshen formula (TSF) was used as an example for complex CHM formulas. The UHPLC-Q-Orbitrap HRMS was firstly applied to identify or tentatively assign 85 compounds in TSF. Subsequently, key active compounds for TSF treating diabetic nephropathy (DN) were chose by chemical-target-pathways network in network pharmacology. The results showed that 13 key bioactive compounds against DN including naringin, daidzein, genistein, formononetin, chlorogenic acid, aloe-emodin, nobiletin, tangeritin, ginsenoside Rg1, hesperetin, hesperidin, rhein, and limonin with three high topological features in chemical-target-pathways network were selected as Q-markers for quality control of TSF. Finally, the UHPLC-MS/MS was performed to simultaneously determine the concentrations of 13 Q-markers. And their concentrations were ranged from 11.57 to 3 788 µg·g^-1. It suggested that many key bioactive compounds not only have high contents but also have wide range contents for the quality of complex CHM formulas. This study should be helpful to guide the selection of the Q-markers and provide new strategy for quality control of complex CHM formulas.

Protective Effect of Tangshen Formula () on Interstitial Cells of Cajal in Colon of Diabetic Rats

OBJECTIVE

To explore the effect of Tangshen Formula (, TSF), a Chinese herbal medicine, on interstitial cells of Cajal (ICC) in the colon of diabetic rats.

METHODS

Fifty-four male Wistar rats were randomly divided into normal control (NC, n=14) and high-fat diet (HFD) groups (n=40). After 6 weeks, the rats in the HFD group were injected intraperitoneally streptozotocin once (30 mg/kg). Thirty rats with fasting blood glucose higher than 11.7 mmol/L were randomly divided into diabetes (DM) and TSF groups, 15 rats in each group. Rats in the NC and DM groups were intragastrically administered with saline, and those in the TSF group were given with TSF (2.4 g/kg) once daily for 20 weeks. Expression levels of Bax, Bcl-2, and caspase-3 in colonic smooth muscle layer were measured by Western blotting and immunohistochemical staining. The number of ICC was determined by immunohistochemical staining. Immunofluorescence was used for analyzing the ratio of classically activated macrophages (M1) and alternatively activated macrophages (M2) to total macrophages. Electron microscopy was used to observe the epithelial ultrastructure and junctions.

RESULTS

TSF appeared to partially prevented loss of ICC in DM rats (P<0.05). Compared with the NC group, expression levels of Bcl-2, Bax, caspase-3, and TNF-α as well as the ratio of M1 to total macrophages increased in DM rats (all P<0.05), and the ratio of M2 to total macrophages decreased (P<0.05 or P<0.01). Compared with the DM group, TSF decreased the expression levels of abovementioned proteins and restore M2 to total macrophages ratio (P<0.05 or P<0.01). TSF appeared to attenuate the ultrastructural changes of epithelia and improve the tight and desmosome junctions between epithelia reduced in the DM rats.

CONCLUSION

Reduced number of ICC in DM rats may be associated with damage of the intestinal barrier. The protective effects of TSF on ICC may be through repair of the epithelial junctions, which attenuates inflammation and inflammation-initiated apoptosis in colon of DM rats.

Morroniside Promotes PGC-1α-Mediated Cholesterol Efflux in Sodium Palmitate or High Glucose-Induced Mouse Renal Tubular Epithelial Cells

Lipid deposition is an etiology of renal damage caused by lipid metabolism disorder in diabetic nephropathy (DN). Thus, reducing lipid deposition is a feasible strategy for the treatment of DN. Morroniside (MOR), an iridoid glycoside isolated from the Chinese herb Cornus officinalis Sieb. et Zucc., is considered to be an effective drug in inhibiting oxidative stress, reducing inflammatory response, and countering apoptosis. To explore the protective mechanism of MOR in attenuating renal lipotoxicity in DN, we investigated the effect of MOR on an in vitro model of lipid metabolism disorder of DN established by stimulating mouse renal tubular epithelial cells (mRTECs) with sodium palmitate (PA) or high glucose (HG). Oil Red O and filipin cholesterol staining assays were used to determine intracellular lipid accumulation status. Results revealed that PA or HG stimulation inhibited the expressions of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), liver X receptors (LXR), ATP-binding cassette subfamily A member 1 (ABCA1), ABCG1, and apolipoprotein E (ApoE) in mRTECs as evidenced by western blot and quantitative real-time PCR, resulting in increased intracellular lipid deposition. Interestingly, MOR upregulated expressions of PGC-1α, LXR, ABCA1, ABCG1, and ApoE, thus reducing cholesterol accumulation in mRTECs, suggesting that MOR might promote cholesterol efflux from mRTECs via the PGC-1α/LXR pathway. Of note, silencing PGC-1α reversed the promotive effect of MOR on PA- or HG-induced cellular cholesterol accumulation. In conclusion, our results suggest that MOR has a protective effect on mRTECs under high lipid or high glucose conditions, which may be related to the promotion of intracellular cholesterol efflux mediated by PGC-1α.

Qian Yang Yu Yin Granule Improves Renal Injury of Hypertension by Regulating Metabolic Reprogramming Mediated by HIF-1α/PKM2 Positive Feedback Loop

Protection against hypoxia injury is an important therapeutic strategy for treating hypertensive nephropathy. In this study, the effects of Qian Yang Yu Yin granule (QYYY) on spontaneously hypertensive rats fed with high salt diet and HEK293T cells exposed to hypoxia were investigated. After eight weeks' treatment of QYYY, blood pressure, serum creatinine, serum cystatin C, blood urea nitrogen, urinary β2-microglobulin, urinary N-acetyl-β-glucosaminidase, and urinary microalbumin were assessed. The changes of hypoxia-inducible factor-1α (HIF-1α), pyruvate kinase M2 (PKM2), glucose transport 1 (GLUT1), lactate dehydrogenase A (LDH-A), connective tissue growth factor (CTGF), transforming growth factor-β1 (TGF-β1), ATP, lactate, pyruvate, and pathology were also assessed in vivo. HEK293T cells pre-treated with QYYY and/or HIF-1α over expressing cells were cultured in a three gas hypoxic incubator chamber (5% CO₂, 1% O₂, 94% N₂) for 12 h and then the expressions of HIF-1α, PKM2, GLUT1, LDH-A, CTGF, TGF-β1, ATP, lactate, and pyruvate were detected. Our results showed that QYYY promoted the indicators of renal inflammation and fibrosis mediated by HIF-1α/PKM2 positive feedback loop in vivo and vitro. Our findings indicated that QYYY treated hypertensive nephropathy by regulating metabolic reprogramming mediated by HIF-1α/PKM2 positive feedback loop.

Metabolomic analysis of a selective ABCA1 inducer in obesogenic challenge provides a rationale for therapeutic development

BACKGROUND

Therapeutic agents with novel mechanisms of action are needed to combat the growing epidemic of type 2 diabetes (T2D) and related metabolic syndromes. Liver X receptor (LXR) agonists possess preclinical efficacy yet produce side effects due to excessive lipogenesis. Anticipating that many beneficial and detrimental effects of LXR agonists are mediated by ABCA1 and SREPB1c expression, respectively, we hypothesized that a phenotypic optimization strategy prioritizing selective ABCA1 induction would identify an efficacious lead compound with an improved side effect profile over existing LXRβ agonists.

METHODS

We synthesized and characterized a novel small molecule for selective induction of ABCA1 vs. SREBP1c in vitro. This compound was evaluated in both wild-type mice and a high-fat diet (HFD) mouse model of obesity-driven diabetes through functional, biochemical, and metabolomic analysis.

FINDINGS

Six weeks of oral administration of our lead compound attenuated weight gain, glucose intolerance, insulin signaling deficits, and adiposity. Global metabolomics revealed suppression of gluconeogenesis, free fatty acids, and pro-inflammatory metabolites. Target identification linked these beneficial effects to selective LXRβ agonism and PPAR/RXR antagonism.

INTERPRETATION

Our observations in the HFD model, combined with the absence of lipogenesis and neutropenia in WT mice, support this novel approach to therapeutic development for T2D and related conditions.

Tangshen Formula Attenuates Diabetic Kidney Injury by Imparting Anti-pyroptotic Effects via the TXNIP-NLRP3-GSDMD Axis

We previously reported that Tangshen formula (TSF), a Chinese herbal medicine for diabetic kidney disease (DKD) therapy, imparts renal protective effects. However, the underlying mechanisms of these effects remain unclear. Pyroptosis is a form of programmed cell death that can be triggered by the NLRP3 inflammasome. Recently, the association between the pyroptosis of renal resident cells and DKD was established, but with limited evidence. This study aimed to investigate whether the renal protective effects of TSF are related to its anti-pyroptotic effect. DKD rats established by right uninephrectomy plus a single intraperitoneal injection of STZ and HK-2 cells stimulated by AGEs were used. In vivo, TSF reduced the 24 h urine protein (24 h UP) of DKD rats and alleviated renal pathological changes. Meanwhile, the increased expression of pyroptotic executor (GSDMD) and NLRP3 inflammasome pathway molecules (NLRP3, caspase-1, and IL-1β) located in the tubules of DKD rats were downregulated with TSF treatment. In vitro, we confirmed the existence of pyroptosis in AGE-stimulated HK-2 cells and the activation of the NLRP3 inflammasome. TSF reduced pyroptosis and NLRP3 inflammasome activation in a dosage-dependent manner. Then, we used nigericin to determine that TSF imparts anti-pyroptotic effects by inhibiting the NLRP3 inflammasome. Finally, we found that TSF reduces reactive oxygen species (ROS) production and thioredoxin-interacting protein (TXNIP) expression in AGE-stimulated HK-2 cells. More importantly, TSF decreased the colocalization of TXNIP and NLRP3, indicating that ROS-TXNIP may be the target of TSF. In summary, the anti-pyroptotic effect via the TXNIP-NLRP3-GSDMD axis may be an important mechanism of TSF for DKD therapy.

Mitochondrial Dysfunction and Diabetic Nephropathy: Nontraditional Therapeutic Opportunities

Diabetic nephropathy (DN) is a progressive microvascular diabetic complication. Growing evidence shows that persistent mitochondrial dysfunction contributes to the progression of renal diseases, including DN, as it alters mitochondrial homeostasis and, in turn, affects normal kidney function. Pharmacological regulation of mitochondrial networking is a promising therapeutic strategy for preventing and restoring renal function in DN. In this review, we have surveyed recent advances in elucidating the mitochondrial networking and signaling pathways in physiological and pathological contexts. Additionally, we have considered the contributions of nontraditional therapy that ameliorate mitochondrial dysfunction and discussed their molecular mechanism, highlighting the potential value of nontraditional therapies, such as herbal medicine and lifestyle interventions, in therapeutic interventions for DN. The generation of new insights using mitochondrial networking will facilitate further investigations on nontraditional therapies for DN.

High Glucose Aggravates Cholesterol Accumulation in Glomerular Endothelial Cells Through the LXRs/LncRNAOR13C9/ABCA1 Regulatory Network

BACKGROUND

The underlying mechanisms by which diabetes and dyslipidemia contribute to diabetic nephropathy (DN) are not fully understood. In this study, we aimed to investigate the role of high glucose (HG) on intracellular cholesterol accumulation in glomerular endothelial cells (GEnCs) and its potential mechanism.

METHODS

Oil red O staining, RT-qPCR, Western blotting, and immunocytofluorescence analyses were used to determine cholesterol accumulation and the expressions of LXRs and ABCA1 in GEnCs under high cholesterol (HC) and/or HG conditions, and the effect of these treatments was compared to that of low glucose without adding cholesterol. LncRNA microarrays were used to identify a long non-coding RNA (LncRNA OR13C9), of which levels increased in cells treated with the LXR agonist, GW3965. Fluorescence in situ hybridization (FISH) was conducted to confirm subcellular localization of LncOR13C9 and a bioinformatics analysis was used to identify competing endogenous RNA (ceRNA) regulatory networks between LncOR13C9 and microRNA-23a-5p (miR-23a-5p). Gain and loss of function, rescue assay approaches, and dual-luciferase reporter assay were conducted to study interactions between LncOR13C9, miR-23a-5p, and ABCA1.

RESULTS

We showed that HG could decrease the response ability of GEnCs to cholesterol load, specifically that HG could downregulate LXRs expression in GEnCs under cholesterol load and that the decrease in LXRs expression suppressed ABCA1 expression and increased cholesterol accumulation. We focused on the targets of LXRs and identified a long non-coding RNA (LncOR13C9) that was downregulated in GEnCs grown in HG and HC conditions, compared with that grown in HC conditions. We speculated that LncRNAOR13C9 was important for LXRs to increase cholesterol efflux via ABCA1 under HC. Furthermore, using gain of function, loss of function, and rescue assay approaches, we showed that LncOR13C9 could regulate ABCA1 by inhibiting the action of miR-23a-5p in the LXR pathway. Furthermore, dual-luciferase reporter assay was conducted to study the interaction of LncOR13C9 with miR-23a-5p.

CONCLUSION

Overall, our study identified the LXRs/LncOR13C9/miR23A-5p/ABCA1 regulatory network in GEnCs, which may be helpful to better understand the effect of HG on cholesterol accumulation in GEnCs under cholesterol load and to explore new therapeutic tools for the management of DN patients.

Protective Role of Tangshen Formula on the Progression of Renal Damage in db/db Mice by TRPC6/Talin1 Pathway in Podocytes

Tangshen Formula (TSF) is a Chinese Medicine formula that has been reported to alleviate proteinuria and protect renal function in humans and animals with diabetic kidney disease (DKD). However, little is known about its mechanism in improving proteinuria. The dysregulation of podocyte cell-matrix adhesion has been demonstrated to play an important role in the pathogenesis and progression of proteinuric kidney diseases including DKD. In the present study, the underlying protective mechanism of TSF on podocytes was investigated using the murine model of type 2 DKD db/db mice in vivo and advanced glycation end products (AGEs)-stimulated primary mice podocytes in vitro. Results revealed that TSF treatment could significantly mitigate reduction of podocyte numbers and foot process effacement, reduce proteinuria, and protect renal function in db/db mice. There was a significant increase in expression of transient receptor potential canonical channel 6 (TRPC6) and a decrease in expression of talin1 in podocytes of db/db mice. The results of AGEs-stimulated primary mice podocytes showed increased cell migration and actin-cytoskeleton rearrangement. Moreover, primary mice podocytes stimulated by AGEs displayed an increase in TRPC6-dependent Ca2+ influx, a loss of talin1, and translocation of nuclear factor of activated T cell (NFATC) 2. These dysregulations in mice primary podocytes stimulated by AGEs could be significantly attenuated after TSF treatment. 1-Oleoyl-2-acetyl-sn-glycerol (OAG), a TRPC6 agonist, blocked the protective role of TSF on podocyte cell-matrix adherence. In conclusion, TSF could protect podocytes from injury and reduce proteinuria in DKD, which may be mediated by the regulation of the TRPC6/Talin1 pathway in podocytes.

Lipotoxicity and Diabetic Nephropathy: Novel Mechanistic Insights and Therapeutic Opportunities

Lipotoxicity is characterized by the ectopic accumulation of lipids in organs different from adipose tissue. Lipotoxicity is mainly associated with dysfunctional signaling and insulin resistance response in non-adipose tissue such as myocardium, pancreas, skeletal muscle, liver, and kidney. Serum lipid abnormalities and renal ectopic lipid accumulation have been associated with the development of kidney diseases, in particular diabetic nephropathy. Chronic hyperinsulinemia, often seen in type 2 diabetes, plays a crucial role in blood and liver lipid metabolism abnormalities, thus resulting in increased non-esterified fatty acids (NEFA). Excessive lipid accumulation alters cellular homeostasis and activates lipogenic and glycogenic cell-signaling pathways. Recent evidences indicate that both quantity and quality of lipids are involved in renal damage associated to lipotoxicity by activating inflammation, oxidative stress, mitochondrial dysfunction, and cell-death. The pathological effects of lipotoxicity have been observed in renal cells, thus promoting podocyte injury, tubular damage, mesangial proliferation, endothelial activation, and formation of macrophage-derived foam cells. Therefore, this review examines the recent preclinical and clinical research about the potentially harmful effects of lipids in the kidney, metabolic markers associated with these mechanisms, major signaling pathways affected, the causes of excessive lipid accumulation, and the types of lipids involved, as well as offers a comprehensive update of therapeutic strategies targeting lipotoxicity.

Association between LXR-α and ABCA1 Gene Polymorphisms and the Risk of Diabetic Kidney Disease in Patients with Type 2 Diabetes Mellitus in a Chinese Han Population

We designed a case-control study and selected LXR-α rs7120118 C>T and ABCA1 rs2230806 A>G polymorphisms to determine the correlation between these polymorphisms and diabetic kidney disease (DKD) susceptibility in a Chinese Han population. Three hundred DKD patients and 346 type 2 diabetes mellitus (DM) patients without kidney disease were recruited. Our results showed that rs7120118 was associated with DKD (genotype, P = .027; allele, P < .011). rs7120118 was associated with a higher risk of DKD under a dominant model adjustment by age and sex (P = .015) and an additive model (P = .040); rs2230806 was associated with a higher risk of DKD under an recessive model (P < .03); the combined effect of rs7120118 CC+rs2230806 GG genotype showed an association of DKD adjustment for age and sex (P = .009). In subgroup analysis of patients without hypercholesterolemia, the rs2230806 genotype frequencies were different between the two groups (P = .042). rs2230806 was associated with increased risk of DKD under a recessive model adjustment for age and sex (P = .013) and an additive model (P = .031). Our results suggest that LXR-α rs7120118 is significantly associated with a higher risk of DKD, and ABCA1 rs2230806 is significantly associated with a higher risk of DKD without hypercholesterolemia in Chinese Han individuals.

Evidence and potential mechanisms of traditional Chinese medicine for the treatment of type 2 diabetes: A systematic review and meta-analysis

Traditional Chinese medicine (TCM) has recorded knowledge of diabetes for over 2000 years. Because a considerable number of TCM studies exhibit design defects, such as limited intervention duration, small sample sizes and inconsistent efficacy evaluations, the role of TCM in the treatment of diabetes cannot be fully elucidated. In this review, we evaluate randomized controlled trials of prediabetes, diabetes and diabetic complications published in the past decade. We found that TCM could significantly improve glucose control and clinical indices in patients with diabetes and effectively delay the progression of diabetes. We also summarize potential pharmacological mechanisms underlying the efficacy of TCM medication/herbs and their active ingredients for treating diabetes. More rigorously designed experiments and long-term evaluation of TCM for diabetes will allow for more effective diabetes management.

Formononetin alleviates hepatic steatosis by facilitating TFEB-mediated lysosome biogenesis and lipophagy

Formononetin has been reported to ameliorate hyperlipidemia and obesity, but its effect and mechanism of action in anti-non-alcoholic fatty liver disease (NAFLD) remain unclear. Lipophagy is a critical protective mechanism during steatosis development that results in the decomposition of lipid droplets through autophagy and the prevention of cellular lipid accumulation. This study aimed to investigate the beneficial role of formononetin in treating NAFLD and explore the mechanism of lipophagy in formononetin anti-hepatic steatosis effects. Formononetin treatment significantly ameliorated hepatic steatosis in HFD mice. Consistently, formononetin also reduced FFAs-stimulated lipid accumulation in HepG2 cells and primary mouse hepatocytes. Further analysis revealed that steatosis increased LC3B-II, a marker of autophagy, but caused blockade of autophagic flux associated with a lack of lysosomes. Treatment with formononetin promoted lysosome biogenesis and autophagosome-lysosome fusion, relieving the blockade in autophagic flux and further induced lipophagy. Mechanistically, formononetin activated adenosine monophosphate activated protein kinase (AMPK) and promoted subsequent nuclear translocation of transcription factor EB (TFEB), a key regulator of lysosome biogenesis. TFEB inhibition markedly abolished formononetin-induced lysosome biogenesis, autophagosome-lysosome fusion and lipophagy and concomitantly alleviated lipid accumulation. Formononetin improved hepatic steatosis via TFEB-mediated lysosome biogenesis, which provides new evidence regarding formononetin's anti-NAFLD effects.

Tangshen Formula Alleviates Hepatic Steatosis by Inducing Autophagy Through the AMPK/SIRT1 Pathway

Tangshen formula (TSF), a formula of Chinese herbal medicine, improves lipid metabolism in humans and animals with diabetic kidney disease. However, the effect and mechanism of TSF on nonalcoholic fatty liver disease (NAFLD) remain unclear. The activation of autophagy appears to be a potential mechanism for improving NAFLD. In the present study, we examined the therapeutic effect of TSF on hepatic steatosis and sought to explore whether its effect is related to activating autophagy. Here, we showed that TSF treatment significantly attenuated hepatic steatosis in both high-fat diet (HFD) and methionine choline-deficient diet (MCDD)-fed mice. Meanwhile, TSF reduced lipid accumulation in palmitate (PA)-stimulated HepG2 cells and primary mouse hepatocytes. Furthermore, TSF increased Sirtuin 1 (SIRT1) expression and promoted autophagy activation in vivo. TSF also improved PA-induced suppression of both SIRT1 expression and SIRT1-dependent autophagy, thereby alleviating intracellular lipid accumulation in vitro. In addition, TSF increased SIRT1 expression and induced autophagy in an adenosine monophosphate-activated protein kinase (AMPK)-dependent manner. Moreover, SIRT1 knockdown abolished the autophagy-inducing and lipid-lowering effects of TSF. In conclusion, TSF improved lipid accumulation and hepatic steatosis by inducing the AMPK/SIRT1 pathway-mediated autophagy.

Identification of potential therapeutic target genes in mouse mesangial cells associated with diabetic nephropathy using bioinformatics analysis

The aim of the present study was to identify genes under the effect of transforming growth factor-β (TGF-β1), high glucose (HG) and glucosamine (GlcN) in MES-13 mesangial cells and elucidate the molecular mechanisms of diabetic nephropathy (DN). The gene expression datasets GSE2557 and GSE2558 were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were independently screened using the GEO2R online tool. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the Database for Annotation, Visualization, and Integrated Discovery. The protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes and Cytoscape software. The hub genes were identified by the NetworkAnalyzer plugin. Overlapping genes were subjected to molecular docking analysis using SystemsDock. A total of 202 upregulated and 158 downregulated DEGs from the HG-treated groups, 138 upregulated and 103 downregulated DEGs from the GlcN-treated groups, and 81 upregulated and 44 downregulated DEGs from the TGF-β1-treated groups were identified. The majority of the DEGs were independently enriched in 'nucleosome assembly', 'chromatin silencing' and 'xenobiotic glucuronidation'. In addition, KEGG pathways were significantly enriched in 'systemic lupus erythematosus', 'protein processing in endoplasmic reticulum' and 'aldarate metabolism pathway', and 'TNF signaling pathway' intersected in the TGF-β1-treated and HG-treated groups. In total, eight hub genes, Jun, prostaglandin-endoperoxide synthase 2 (Ptgs2), fibronectin 1 (Fn1), cyclin-dependent kinase (Cdk)2, Fos, heat shock protein family A (Hsp70) member 5 (Hspa5), Hsp90b1 and homo sapiens hypoxia upregulated 1 (Hyou1), and three overlapping genes, Ras homolog gene family, member B (RHOB), complement factor H (CFH) and Krüppel-like factor 15 (KLF15), were selected. Valsartan with RHOB, and fosinopril with CFH and KLF15 had preferential binding activity. In conclusion, Jun, Ptgs2, Fn1, Cdk2, Fos, Hspa5, Hsp90b1, Hyou1, RHOB, CFH and KLF15 may be potential therapeutic targets for mesangial cells associated with DN, which may provide insight into DN treatment strategies.

Calycosin Ameliorates Diabetes-Induced Renal Inflammation via the NF-κB Pathway In Vitro and In Vivo

BACKGROUND Diabetic nephropathy (DN), which is one of the primary causes of end-stage renal disease (ESRD), is increasingly diagnosed in patients due to the continuous increase in the prevalence of diabetic mellitus (DM). Astragali Radix, a traditional Chinese herb, is widely administrated to ameliorate the symptoms of diabetes and diabetic nephropathy, but its mechanism is still not yet fully defined. Calycosin (C₁₆H₁₂O₅) is the major active component of Astragali Radix. In this study, we analyzed the role of calycosin in diabetic nephropathy and explored its underlying mechanism. MATERIAL AND METHODS Cell activation, inflammatory cytokines expression and secretion, and protein levels were analyzed in cultured mouse tubular epithelial cells (mTEC). db/db mice were intraperitoneally injected with 10 mg/(kg·d) calycosin or control saline for 4 weeks, followed by analysis of structure injury, inflammation, and NF-κB signaling activity. RESULTS Our results indicated that TNF-α and IL-1β were significantly induced by advanced glycation end-products (AGEs), but calycosin remarkably reduced the expression of TNF-α and IL-1β in the cultured mouse tubular epithelial cells (mTEC). Calycosin effectively alleviated kidney injury in diabetic kidneys of db/db mice during the progression of diabetic renal injury, indicated by the reduction of histological injury and immunohistochemical of inflammatory cytokines. Mechanistically, we identified calycosin inhibited diabetes-induced inflammation in kidneys by suppressing the phosphorylation of IKBa and NF-κB p65 in vitro and in vivo. CONCLUSIONS Calycosin significantly ameliorated diabetes-induced renal inflammation in diabetic renal injury by inhibition of the NF-κB-dependent signaling pathway in vivo and in vitro.