Kaempferitrin attenuates unilateral ureteral obstruction-induced renal inflammation and fibrosis in mice by inhibiting NOX4-mediated tubular ferroptosis.

Tubular ferroptosis significantly contributes to renal inflammation and fibrosis, critical factors in chronic kidney disease (CKD). This study aims to investigate Kaempferitrin, a potent flavonoid glycoside from Bauhinia forficata leaves, renowned for its anti-inflammatory and antitumor effects, and to elucidate its potential mechanisms in mitigating inflammation and fibrosis induced by tubular ferroptosis. The study investigated Kaempferitrin's impact on tubular ferroptosis using a unilateral ureteral obstruction (UUO) model-induced renal inflammation and fibrosis. In vitro, erastin-induced ferroptosis in primary tubular epithelial cells (TECs) was utilized to further explore Kaempferitrin's effects. Additionally, NADPH oxidase 4 (NOX4) transfection in TECs and cellular thermal shift assay (CETSA) were conducted to identify Kaempferitrin's target protein. Kaempferitrin effectively improved renal function, indicated by reduced serum creatinine and blood urea nitrogen levels. In the UUO model, it significantly reduced tubular necrosis, inflammation, and fibrosis. Its renoprotective effects were linked to ferroptosis inhibition, evidenced by decreased iron, 4-hydroxynonenal (4-HNE), and malondialdehyde (MDA) levels, and increased glutathione (GSH). Kaempferitrin also normalized glutathione peroxidase 4 (GPX4) and Solute Carrier Family 7 Member 11(SLC7A11) expression, critical ferroptosis mediators. In vitro, it protected TECs from ferroptosis and consistently suppressed NOX4 expression. NOX4 transfection negated Kaempferitrin's antiferroptosis effects, while CETSA confirmed Kaempferitrin-NOX4 interaction. Kaempferitrin shows promise as a nephroprotective agent by inhibiting NOX4-mediated ferroptosis in tubular cells, offering potential therapeutic value for CKD.

A renal YY1-KIM1-DR5 axis regulates the progression of acute kidney injury.

Acute kidney injury (AKI) exhibits high morbidity and mortality. Kidney injury molecule-1 (KIM1) is dramatically upregulated in renal tubules upon injury, and acts as a biomarker for various renal diseases. However, the exact role and underlying mechanism of KIM1 in the progression of AKI remain elusive. Herein, we report that renal tubular specific knockout of Kim1 attenuates cisplatin- or ischemia/reperfusion-induced AKI in male mice. Mechanistically, transcription factor Yin Yang 1 (YY1), which is downregulated upon AKI, binds to the promoter of KIM1 and represses its expression. Injury-induced KIM1 binds to the ECD domain of death receptor 5 (DR5), which activates DR5 and the following caspase cascade by promoting its multimerization, thus induces renal cell apoptosis and exacerbates AKI. Blocking the KIM1-DR5 interaction with rationally designed peptides exhibit reno-protective effects against AKI. Here, we reveal a YY1-KIM1-DR5 axis in the progression of AKI, which warrants future exploration as therapeutic targets.

Reflections on TRP and TP/GFR in the definition of renal phosphate loss: conceptual review.

BACKGROUND: Fractional tubular reabsorption of phosphate (TRP) has been used for over 60 years to establish the existence of renal phosphate loss. It is a parameter of corrected volume per decilitre of glomerular filtration rate (GFR). Later, a mass parameter per dl GFR called TP/GFR (tubular PO4 reabsorption per dl GFR) was devised which some authors have sought to substitute for TRP. The aim of the present work is to attempt to demonstrate that TRP and TP/GFR are similar parameters and, in certain aspects, TRP is more effective for diagnosis. METHODS: Data were gathered on the metabolism of phosphate corresponding to a group of healthy children without hypophosphatemia (n = 47), a group of patients with idiopathic hypercalciuria (n = 27), and ten patients diagnosed with X-linked hypophosphatemia (XLH). The TRP, the TP/GFR, and the percent tubular reabsorption of phosphate were calculated. RESULTS: All the patients with XLH presented TRP values lower than 95 ml/dl GFR and of TP/GFR equal to or lower than 2.8 mg/dl GFR. In the total sample, a direct correlation was observed between TRP and TP/GFR (r = 0.65; p = 0.01). The TRP and the percent tubular reabsorption of phosphate values were the same in the three groups (r = 1; p = 0.01). CONCLUSIONS: TRP and TP/GFR are similar parameters. TRP is more effective than TP/GFR given that in renal hypophosphatemia it is always below 95% and above 95% in reduced phosphatemia and normal kidney proximal tubular function. There is no solid reason for using TP/GFR rather than TRP. A higher resolution version of the Graphical abstract is available as Supplementary information.

Asiatic acid attenuates tubular injury in diabetic kidney disease by regulating mitochondrial dynamics via the Nrf-2 pathway.

BACKGROUND: Mitochondrial dynamics plays a crucial role in tubular injury in diabetic kidney disease (DKD). Asiatic acid (AA) has demonstrated renal protective effects in DKD; however, its therapeutic effect on tubular injury in DKD remains unclear. PURPOSE: This study aimed to verify the effects of AA on tubular injury in DKD and underlying mechanisms. STUDY DESIGN: In the present study, the effects of AA on tubular injury were assessed in rats with streptozotocin-induced diabetes and advanced glycation end products (AGEs)-stimulated HK-2 cells models. METHODS: After oral administration with or without AA for ten weeks, body weight and levels of fast blood glucose, serum creatinine (sCr), blood urea nitrogen (BUN), urinary albumin, and kidney injury molecule-1 (KIM-1) were detected. Histological analysis was performed to evaluate the renal function of rats. Moreover, the expression of proteins associated with the Nrf-2 pathway and mitochondrial dynamics was analyzed. AGEs-stimulated HK-2 cells were examined to evaluate the tubular protection and the mechanism of AA in vitro. RESULTS: AA remarkably decreased albumin levels, KIM-1 levels in urine, and serum Cr, and BUN levels. In addition, AA prevented tubular injury and mitochondrial injury by regulating the Nrf-2 pathway and mitochondrial dynamics. Furthermore, the effects of AA on mitochondrial dynamics and tubular protection were eliminated after treatment with ML385 (Nrf2 inhibitor). CONCLUSION: These findings suggested that AA might be developed as a potential candidate for the treatment of tubular injury in DKD, and its effects are potentially mediated via the regulation of the Nrf-2 pathway and mitochondrial dynamics.

Tubule-mitophagic secretion of SerpinG1 reprograms macrophages to instruct anti-septic acute kidney injury efficacy of high-dose ascorbate mediated by NRF2 transactivation.

High-dose ascorbate confers tubular mitophagy responsible for septic acute kidney injury (AKI) amelioration, yet its biological roles in immune regulation remain poorly understood. Methods: The role of tubular mitophagy in macrophage polarization upon high-dose ascorbate treatment was assessed by fluorescence-activated cell sorter analysis (FACS) in vitro and by immunofluorescence in AKI models of LPS-induced endotoxemia (LIE) from Pax8-cre; Atg7 flox/flox mice. The underlying mechanisms were revealed by RNA-sequencing, gene set enrichment analysis (GSEA), luciferase reporter, chromatin immunoprecipitation (ChIP) and adeno-associated viral vector serotype 9 (AAV9) delivery assays. Results: High-dose ascorbate enables conversion of macrophages from a pro-inflammatory M1 subtype to an anti-inflammatory M2 subtype in murine AKI models of LIE, leading to decreased renal IL-1ß and IL-18 production, reduced mortality and alleviated tubulotoxicity. Blockade of tubular mitophagy abrogates anti-inflammatory macrophages polarization under the high-dose ascorbate-exposed coculture systems. Similar abrogations are verified in LIE mice with tubular epithelium-specific ablation of Atg7, where the high-dose ascorbate-inducible renal protection and survival improvement are substantially weaker than their control littermates. Mechanistically, high-dose ascorbate stimulates tubular secretion of serpin family G member 1 (SerpinG1) through maintenance of mitophagy, for which nuclear factor-erythroid 2 related factor 2 (NRF2) transactivation is required. SerpinG1 perpetuates anti-inflammatory macrophages to prevent septic AKI, while kidney-specific disruption of SerpinG1 by adeno-associated viral vector serotype 9 (AAV9)-short hairpin RNA (shRNA) delivery thwarts the anti-inflammatory macrophages polarization and anti-septic AKI efficacy of high-dose ascorbate. Conclusion: Our study identifies SerpinG1 as an intermediate of tubular mitophagy-orchestrated myeloid function during septic AKI and reveals a novel rationale for ascorbate-based therapy.

[Electroacupuncture pretreatment alleviates apoptosis of renal tubular epithelia cells by down-regulating expression of TRPC6 in hyperglycemic mice].

OBJECTIVE: To observe the effect of electroacupuncture (EA) pretreatment on apoptosis of renal tubular epithelial cells in mice with hyperglycemia, so as to explore its mechanisms underlying protecting the kidney from hyperglycemia-induced injury. METHODS: Eighty male C57BL/6 mice were equally and randomly divided into control, model, EA and sham EA groups. The hyperglycemia model was established by intraperitoneal injection of streptozocin (STZ, 50 mg·kg-1·d-1) for 5 consecutive days. Before modeling, EA (2 Hz/15 Hz, 0.3-0.5 mA) was applied to bilateral "Zusanli" (ST36) and "Shenshu" (BL23) for 30 min, once daily for 7 days, while mice in the sham EA group were treated with the same acupoints but without electrical stimulation. The blood glucose values were measured after fasting for 6 hours after 3 days of modeling. The degree of renal tissue injury was observed by microscope after H.E. staining, and the apoptosis level of renal tubular epithelial cells observed by TUNEL staining. The expression levels of transient receptor potential channel 6 (TRPC6) and related apoptotic proteins Caspase-3, Bax and Bcl-2 in the renal tissue were detected by Western blot and immunohistochemistry, separately. RESULTS: Compared with the control group, the blood glucose content and the expression levels of TRPC6, Caspase-3 and Bax proteins, as well as the level of the renal apoptotic cells were significantly increased (P<0.001, P<0.000 1), while the expression level of Bcl-2 protein and the ratio of Bcl-2/Bax were remarkably decreased in the model group (P<0.000 1). In comparison with the model and sham EA groups, the blood glucose content, percentage of apoptotic cells and the expression levels of TRPC6, Caspase-3 and Bax were significantly decreased (P<0.01, P<0.000 1, P<0.05, P<0.001), and the expression level of Bcl-2 and the ratio of Bcl-2/Bax were apparently increased in the EA group (P<0.01, P<0.05, P<0.001). HE statin showed abnormal dilation of the capillary lumen and disappearance of the proximal tubules in the model group, which was relatively milder in the EA group. CONCLUSION: EA pretreatment can lower blood glucose level and reduce renal apoptosis in hyperglycemia mice, which may be related to its effects in down-regulating the expression of TRPC6 and Caspase-3 and up-regulating the ratio of Bcl-2/Bax.

[Tanshinone IIA alleviates lipopolysaccharide-induced renal tubular epithelial cell apoptosis by inhibiting RIP3/FUNDC1 signaling pathway].

OBJECTIVE: To investigate the effect of tanshinone IIA pretreatment on acute renal injury in lipopolysaccharide (LPS)-induced septic mice and explore the possible mechanism. METHODS: Thirty C57BL/6 mice were randomized for treatment with saline (control), 10 mg/kg LPS for 24 h, or 10 mg/kg tanshinone IIA 15 min before LPS treatment. After the treatments, serum creatinine and blood urea nitrogen levels of the mice were detected, renal pathologies were observed with PAS staining, and renal expressions of RIP3, cleaved caspase-3 and p18-FUNDC1 were detected with Western blotting. In the cell experiment, cultured normal human renal tubular epithelial cells (HK-2) were treated with LPS (10 mg/mL), LPS+ siNC, LPS+ siRIP3, or LPS+tanshinone IIA (10 mg/L), and the changes in cell apoptosis were examined with TUNEL staining; Western blotting was performed to detect the expression levels of RIP3, cleaved caspase-3 and p18-FUNDC1, and qRT-PCR was used to detect the expression of RIP3 mRNA. RESULTS: LPS challenge for 24 h significantly increased serum creatinine and blood urea nitrogen levels in the mice, caused obviously damages in the proximal renal tubules, and increased renal expressions of RIP3, cleaved caspase-3 and p18-FUNDC1 proteins. Tanshinone IIA pretreatment significantly improved LPS-induced renal injury in the mice, alleviated apoptosis of the renal cells, and inhibited the expressions of RIP3, cleaved caspase-3 and p18-FUNDC1 proteins. In HK-2 cells, LPS stimulation significantly increased the protein expressions of RIP3, cleaved caspase-3 and p18-FUNDC1 and induced obvious cell apoptosis. Pretreatment with tanshinone IIA strongly inhibited the expression of RIP3 and p18-FUNDC1 and reduced LPS-induced apoptosis of HK-2 cells. CONCLUSION: Tanshinone IIA can reduce LPS-induced apoptosis of renal tubular epithelial cells by inhibiting RIP3/FUNDC1 signal pathway.

Selenium Deficiency Leads to Changes in Renal Fibrosis Marker Proteins and Wnt/ß-Catenin Signaling Pathway Components.

Renal fibrosis is the final result of the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD). Earlier studies confirmed that selenium (Se) displays a close association with kidney diseases. However, the correlation between Se and fibrosis has rarely been explored. Thus, this article mainly aimed to investigate the effect of Se deficiency on renal fibrosis and the Wnt/ß-catenin signaling pathway. Twenty BALB/c mice were fed a diet containing 0.02-mg/kg Se (Se-deficient diet) or 0.18-mg/kg Se (standard diet) for 20 weeks. A human glomerular mesangial cell (HMC) cell line was transfected with lentiviral TRNAU1AP-shRNA vector to establish a stable Se deficiency model in vitro. As indicated in this study, the glutathione (GSH) content in the Se-deficient group displayed an obvious decline compared with that in the control group, whereas the content of malondialdehyde (MDA) was obviously elevated. The results of Masson staining showed fibrosis around the renal tubules, and the results of immunohistochemistry showed that the area of positive fibronectin expression increased. In the Se-deficient group, the levels of collagen I, collagen III, matrix metalloproteinase 9 (MMP9), and other fibrosis-related proteins changed significantly in vivo and in vitro. Compared with the control group, the TRNAU1AP-shRNA group showed markedly reduced cell proliferation and migration abilities. Our data indicate that Se deficiency can cause kidney damage and renal fibrosis. Furthermore, the Wnt pathway is critical for the development of tissue and organ fibrosis. The data of this study demonstrated that the expression of Wnt5a, ß-catenin, and dishevelled 1 (Dvl-1) was significantly upregulated in the Se-deficient group. Therefore, the Wnt/ß-catenin pathway may play an important role in renal fibrosis caused by Se deficiency.

Novel pectin-like polysaccharide from Panax notoginseng attenuates renal tubular cells fibrogenesis induced by TGF-ß.

Renal fibrosis is the final common result of a variety of progressive injuries leading to chronic renal failure. However, there are no effective clinical available drugs for the treatment. Notoginsenoside from Panax notoginseng could ameliorate renal fibrosis. We hypothesized that polysaccharide from this herb might have similar bioactivity. Here, we elucidated structure of a novel pectin-like polysaccharide designed SQD4S2 with a netty antenna backbone of glucogalacturonan substituted by glucoarabinan, glucurogalactan and galactose residues from this herb. Interestingly, SQD4S2 could reverse the morphological changes of human renal tubular HK-2 cells induced by TGF-ß. Mechanism study suggested that this bioactivity might associate with N-cadherin (CDH2), Snail (SNAI1), Slug (SNAI2) depression and E-cadherin (CDH1) enhancement. In addition, SQD4S2 could impede critical fibrogenesis associated molecules such as α-SMA, fibronectin, vimentin, COL1A1, COL3A1, FN1 and ACTA2 expression induced by TGF-ß in HK-2 cells. Current findings outline a novel leading polysaccharide for against renal fibrosis new drug development.

Renoprotective activity of Ribes diacanthum pall (RDP) against inflammation in cisplatin-stimulated mice model and human renal tubular epithelial cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Ribes diacanthum Pall (RDP) is mostly distributed in Mongolia. As a Mongolian folk medicinal plant, it is traditionally used to treat kidney diseases by the native inhabitants of Mongolia due to its effect of increasing urine output and eliminating edema. However, its renal protection mechanism remains to be elucidated. AIM OF THE STUDY: To assess the pharmacological mechanism of RDP from an anti-inflammatory point of view using cisplatin (CDDP)-induced kidney injury models in vivo and in vitro. The influence of RDP on the chemotherapy efficacy of CDDP was also evaluated in vitro. MATERIALS AND METHODS: We established a CDDP-induced nephrotoxicity mouse model and a Human Renal Tubular Epithelial (HK-2) damage cellular model, respectively. In vivo, kidney function, the content of urine albumin, and renal histopathology examination were performed to observe the kidney injury. Moreover, the expression and secretion of inflammatory cytokines and adhesive molecules were examined by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and real-time PCR. The key protein levels of mitogen-activated protein kinase/nuclear factor kappa B (MAPK/NF-κB) signaling pathway were measured by western blotting analysis. Electrophoretic mobility shift assay (EMSA) was carried out to detect the activation of NF-κB. In vitro, inflammatory mediators and the proteins related to the NF-κB signaling pathway in HK-2 cells were measured by western blotting analysis. Besides, A549 cell lines were treated with CDDP and RDP to explore RDP's impact on CDDP chemotherapy. RESULTS: Gavage RDP decreased the elevated levels of serum creatinine (Scr), urea nitrogen (BUN), as well as the ratio of urine albumin and creatinine, ameliorated pathological changes of kidney tissue. Correspondingly, the RDP administration group showed a higher survival rate than that of the CDDP exposed group. The expression levels of a plethora of inflammatory mediators were inhibited by RDP treatment compared with the CDDP-exposed group. Furthermore, protein expression levels of MAPK/NF-κB signaling pathway significantly decreased after RDP intervention. For in vitro studies, we confirmed the inhibitory effect of RDP on relative protein expressions involving in the NF-κB pathway. The results also showed that RDP had no impairment on the inhibitory effect of CDDP on A549 cells. CONCLUSION: These findings demonstrated RDP's anti-inflammatory effect against CDDP nephrotoxicity through in vivo and in vitro experiments, and suggested that RDP may have a potential application as an adjuvant medication for CDDP chemotherapy and other inflammatory kidney diseases.

Juzentaihoto improves adenine-induced chronic renal failure in BALB/c mice via suppression of renal fibrosis and inflammation.

Renal inflammation and fibrosis are observed in underlying diseases associated with the pathological progression of chronic kidney disease (CKD). The inhibition of renal inflammation and fibrosis is one method to suppress the progression of CKD. Juzentaihoto (TJ-48), a Kampo medicine, effectively relieves chronic wasting diseases and fatigue and has been reported to decrease inflammation. In this study, we investigated whether TJ-48 has a renal protective effect and its underlying mechanism in mice with adenine-induced CKD. BALB/c mice were divided into four groups for examination: (1) control, (2) dietary restriction, (3) adenine, and (4) adenine + TJ-48. Biochemical and histological analyses, gene expression analysis, and complete blood counts were performed. TJ-48 treatment decreased tubular damage and fibrosis. TJ-48 also decreased creatinine levels exacerbated by adenine, suppressed the mRNA expression of tumor necrosis factor-α, chemokine ligand 2, transforming growth factor-ß, and kidney injury molecule-1, and decreased the neutrophil/lymphocyte ratio increased by adenine. TJ-48 exerts a renoprotective effect possibly via the suppression of fibrosis and inflammation.

Effect of Dapagliflozin and Magnesium Supplementation on Renal Magnesium Handling and Magnesium Homeostasis in Metabolic Syndrome.

The prevalence of metabolic syndrome (MetS) is increasing, and patients with MetS are at an increased risk of cardiovascular disease and diabetes. There is a close link between hypomagnesemia and MetS. Administration of sodium-glucose transporter 2 (SGLT2) inhibitors has been reported to increase serum magnesium levels in patients with diabetes. We investigated the alterations in renal magnesium handling in an animal model of MetS and analyzed the effects of SGLT2 inhibitors. Adult rats were fed a fructose-rich diet to induce MetS in the first 3 months and were then treated with either dapagliflozin or magnesium sulfate-containing drinking water for another 3 months. Fructose-fed animals had increased insulin resistance, hypomagnesemia, and decreased urinary magnesium excretion. Dapagliflozin treatment improved insulin resistance by decreasing glucose and insulin levels, increased serum magnesium levels, and reduced urinary magnesium excretion. Serum vitamin D and parathyroid hormone levels were decreased in fructose-fed animals, and the levels remained low despite dapagliflozin and magnesium supplementation. In the kidney, claudin-16, TRPM6/7, and FXDY expression was increased in fructose-fed animals. Dapagliflozin increased intracellular magnesium concentration, and this effect was inhibited by TRPM6 blockade and the EGFR antagonist. We concluded that high fructose intake combined with a low-magnesium diet induced MetS and hypomagnesemia. Both dapagliflozin and magnesium sulfate supplementation improved the features of MetS and increased serum magnesium levels. Expression levels of magnesium transporters such as claudin-16, TRPM6/7, and FXYD2 were increased in fructose-fed animals and in those administered dapagliflozin and magnesium sulfate. Dapagliflozin enhances TRPM6-mediated trans-epithelial magnesium transport in renal tubule cells.

Effect of Polygonatum odoratum ethanol extract on high glucose-induced tubular epithelial cell apoptosis and oxidative stress.

This work aims to analyze the effect of the ethanol extract from Polygonatum odoratum on high glucose-induced tubular epithelial cell apoptosis and oxidative stress. HK-2 injury of tubular epithelial cells was induced by high glucose, and the ethanol extract from Polygonatum odoratum was given. HK-2 cell activity and apoptosis were detected by MTT method and flow cytometry, respectively. Western blot was performed to analyze Cleaved-caspase3, Pro-caspase3, Nrf2, HO-1 protein expression. The levels of MDA, GSH, SOD were evaluated using commercial Kit. si-Nrf2 was transfected into HK-2 cells and high-glucose induction and ethanol extract from Polygonatum odoratum were given to observe the changes of cell apoptosis and oxidative stress. Ethanol extract from Polygonatum odoratum increased the high glucose-induced HK-2 cell activity, Pro-caspase3, Nrf2, HO-1 protein, GSH, SOD levels and decreased its apoptosis rate, Cleaved-caspase3 protein and MDA levels, showing statistically significant difference (p<0.05). After Nrf2 interference, high glucose-induced HK-2 cell activity, Pro-caspase3 protein, GSH, and SOD levels were decreased under the action of ethanol extract from Polygonatum odoratum, while the apoptosis rate, Cleaved-caspase3 protein, and MDA levels were increased significantly (p<0.05). The ethanol extract from Polygonatum odoratum can inhibit high glucose-induced tubular epithelial cell apoptosis and reduce oxidative stress by activating the Nrf2-ARE signaling pathway.

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.

Establishment of a Drug Screening Model for Cardiac Complications of Acute Renal Failure.

Acute renal failure (ARF) is a clinical critical syndrome with rapid and severe decline of renal function. Complications of ARF, especially its cardiac complications (cardiorenal syndrome type 3, CRS-3), are the main causes of death in patients with ARF. However, the shortage and limited efficacy of therapeutic drugs make it significant to establish new large-scale drug screening models. Based on the Nitroreductase/Metronidazole (NTR/MTZ) cell ablation system, we constructed a Tg(cdh17:Dendra2-NTR) transgenic zebrafish line, which can specifically ablate renal tubular epithelial cells. The absence of renal tubular epithelial cells can lead to ARF in zebrafish larvae. The ARF symptoms, such as heart enlargement, slow heart rate and blood stasis, are similar to the clinical manifestations of human CRS-3. Furthermore, two therapeutic drugs (digoxin and enalapril) commonly used in the clinical treatment of heart failure were also effective in alleviating the symptoms of CRS-3 in zebrafish, which proved the effectiveness of this model. Drug screening further discovered a potential drug candidate, α-lipoic acid, which can effectively alleviate the symptoms of CRS-3 through its antioxidant function. Accordingly, we established a new ARF model of zebrafish, which laid a foundation for large-scale screening of new therapeutic drugs for its complications.

Gypenoside XLIX loaded nanoparticles targeting therapy for renal fibrosis and its mechanism.

Renal fibrosis is the main pathological feature of the occurrence and development of chronic nephropathy. At present, there is no effective treatment, except for renal transplantation and dialysis. Previous studies have shown that nano-preparations can be used as a therapeutic tool to target organs. In this study, we studied the therapeutic effect and mechanism of Chinese medicine monomer Gypenoside (Gyp) XLIX on renal fibrosis and explored the targeting and therapeutic effects of polylactic acid-co-glycoside (PLGA)-Gyp XLIX nanoparticles in unilateral ureteral occlusion (UUO) kidney. Gyp XLIX and PLGA-Gyp XLIX nanoparticles were used to treat UUO mice and Human renal tubular epithelial (HK2) cells stimulated by transforming growth factor-ß (TGF-ß). Histopathological and molecular biological techniques were used to detect the expression of type I collagen and alpha-smooth muscle actin (α-SMA). To investigate the in vivo targeting of PLGA nanoparticles, they were loaded with 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide and injected into UUO mice. We evaluated the effect of Gyp XLIX nanoparticles on TGF-ß/Smad3 pathway, a central driver for renal fibrosis in Smad-deficient HK2 cells. Fluorescence imaging showed that the PLGA nanoparticles around 120 nm could be targeted to the UUO kidney. Compared with Gyp XLIX, PLGA-Gyp XLIX nanoparticles could effectively inhibit renal fibrosis and reduce collagen deposition and reduce renal tubular necrosis. Gyp XLIX decreased the phosphorylation of Smad3, but could not further reduce the levels of type I collagen and α-SMA in Smad-deficient cells. This study opens a promising way for targeted drug treatment of renal fibrosis.

Tinospora cordifolia activates PPARγ pathway and mitigates glomerular and tubular cell injury in diabetic kidney disease.

BACKGROUND: Diabetic Kidney Disease (DKD) is a common complication of diabetes and a leading cause of end-stage renal disease progression. Therefore, therapeutic strategies are desirable to mitigate the progression of disease into more severe consequences. Hypothesis/Purpose:Tinospora cordifolia is a traditionally known antidiabetic plant; however, its effect against DKD remains unexplored. Therefore, in the present study, we assessed the efficacy and mechanism of action of Tinospora cordifolia extract (TC) against DKD. METHODS: The molecular interaction of the various phytoconstituents of TC with PPARγ were analyzed in silico. The effect of TC was studied on the viability, cell cycle, and gene expressions (PPARγ, TGFß, and αSMA) in high glucose treated NRK-52E and SV40 MES13 cells. Further, streptozotocin-induced diabetic rats were treated with TC for eight weeks, and the effects on different biochemical, histological and molecular parameters were studied. RESULTS: In silico analysis revealed the integration of various phytoconstituents of TC with PPARγ. It further increased PPARγ and decreased TGFß and αSMA expressions in NRK-52E and SV40 MES13 cells. In diabetic rats, TC improved the fasting blood glucose, serum urea, and creatinine levels. It also lowered the urine microalbumin and advanced glycation end products (AGEs) levels. Histopathological studies revealed the preventive effect of TC on degenerative changes, mesangial proliferation and glomerular hypertrophy. Further, it reduced the inflammation and fibrotic changes in the kidney tissue estimated by various markers. The kidney tissue and gene expression analysis revealed the augmented levels of PPARγ after TC treatment. CONCLUSION: In conclusion, TC exerted the protective effect against DKD by inhibiting inflammation and fibrogenesis through the activation of PPARγ dependent pathways.

Dual modulatory effects of diosmin on calcium oxalate kidney stone formation processes: Crystallization, growth, aggregation, crystal-cell adhesion, internalization into renal tubular cells, and invasion through extracellular matrix.

Diosmin is a natural flavone glycoside (bioflavonoid) found in fruits and plants with several pharmacological activities. It has been widely used as a dietary supplement or therapeutic agent in various diseases/disorders. Although recommended, evidence of its protective mechanisms against kidney stone disease (nephrolithiasis/urolithiasis), especially calcium oxalate (CaOx) monohydrate (COM) that is the most common type, remained unclear. In this study, we thus systematically evaluated the effects of diosmin (at 2.5-160 nM) on various stages of kidney stone formation processes, including COM crystallization, crystal growth, aggregation, crystal-cell adhesion, internalization into renal tubular cells and invasion through extracellular matrix (ECM). The results showed that diosmin had dose-dependent modulatory effects on all the mentioned COM kidney stone processes. Diosmin significantly increased COM crystal number and mass during crystallization, but reduced crystal size and growth. While diosmin promoted crystal aggregation, it inhibited crystal-cell adhesion and internalization into renal tubular cells. Finally, diosmin promoted crystal invasion through the ECM. Our data provide evidence demonstrating both inhibiting and promoting effects of diosmin on COM kidney stone formation processes. Based on these dual modulatory activities of diosmin, its anti-urolithiasis role is doubtful and cautions should be made for its use in kidney stone disease.

Drug-containing serum of rhubarb-astragalus capsule inhibits the epithelial-mesenchymal transformation of HK-2 by downregulating TGF-ß1/p38MAPK/Smad2/3 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheum palmatum L; Astragalus membranaceus (Fisch.), is referred to as 'Dahuang, Huangqi' in China. As an important medicinal plant, the rhizome of rhubarb and astragalus is traditionally used in the treatment of kidney diseases associated with renal failure, inflammation and tumors. AIM OF THE STUDY: This study aimed to investigate the effect of a drug-containing serum of rhubarb-astragalus capsules (composed of rhubarb and astragalus) and to elucidate its mechanism in the epithelial-mesenchymal transformation of renal tubular epithelial cells. MATERIALS AND METHODS: Epithelial-mesenchymal transformation (EMT) of HK-2 cells was induced by TGF-ß1, and rhubarb-astragalus and losartan drug-containing serum from rats, as well as SB203580 (a specific inhibitor of p38 MAPK), were used. High-performance liquid chromatography analysis was performed to determine the main components of the drug-containing serum of rhubarb-astragalus from rats. Western blotting and immunofluorescence analysis were used to determine the levels of protein expression, and real-time quantitative PCR analysis was used to detect the levels of gene expression. RESULTS: The drug-containing serum of rhubarb-astragalus contained emodin (0.36 µg/ml) and danthraquinone (0.96 µg/ml). Rhubarb-astragalus significantly decreased the protein expression levels of α-SMA, FN, vimentin and N-cadherin in HK-2 cells that were increased by TGF-ß1, while it significantly increased the E-cadherin protein expression level that was decreased by TGF-ß1. Rhubarb-astragalus also significantly decreased the protein expression levels of TGF-ß1 and p38 MAPK and the mRNA expression levels of α-SMA, vimentin, TGF-ß1, p38 MAPK, Smad2 and Smad3 in HK-2 cells that were increased by TGF-ß1. It is worth noting that SB203580 (a p38 MAPK inhibitor) had similar effects as rhubarb-astragalus in this study. CONCLUSION: The drug-containing serum of rhubarb-astragalus can inhibit EMT in HK-2 cells by downregulating the TGF-ß1/p38 MAPK/Smad2/3 pathway.

Transcriptional Suppression of Diabetic Nephropathy with Novel Gene Silencer Pyrrole-Imidazole Polyamides Preventing USF1 Binding to the TGF-ß1 Promoter.

Upstream stimulatory factor 1 (USF1) is a transcription factor that is increased in high-glucose conditions and activates the transforming growth factor (TGF)-ß1 promoter. We examined the effects of synthetic pyrrole-imidazole (PI) polyamides in preventing USF1 binding on the TGF-ß1 promoter in Wistar rats in which diabetic nephropathy was established by intravenous administration of streptozotocin (STZ). High glucose induced nuclear localization of USF1 in cultured mesangial cells (MCs). In MCs with high glucose, USF1 PI polyamide significantly inhibited increases in promoter activity of TGF-ß1 and expression of TGF-ß1 mRNA and protein, whereas it significantly decreased the expression of osteopontin and increased that of h-caldesmon mRNA. We also examined the effects of USF1 PI polyamide on diabetic nephropathy. Intraperitoneal injection of USF1 PI polyamide significantly suppressed urinary albumin excretion and decreased serum urea nitrogen in the STZ-diabetic rats. USF1 PI polyamide significantly decreased the glomerular injury score and tubular injury score in the STZ-diabetic rats. It also suppressed the immunostaining of TGF-ß1 in the glomerulus and proximal tubules and significantly decreased the expression of TGF-ß1 protein from kidney in these rats. These findings indicate that synthetic USF1 PI polyamide could potentially be a practical medicine for diabetic nephropathy.