Akkermansia muciniphila ameliorates chronic kidney disease interstitial fibrosis via the gut-renal axis.

CONTEXT: Chronic kidney disease (CKD) affects approximately 10% of the global population. The abundance of Akkermansia muciniphila (AKK) is significantly reduced in CKD patients. OBJECTIVE: This study investigated the effects of AKK bacteria on kidney damage and the renal interstitium in rats with CKD. MATERIALS AND METHODS: CKD model 5/6 nephrectomy rats were used. CKD rats were supplemented with AKK (2 × 108 cfu/0.2 mL) for 8 weeks. RESULTS: AKK administration significantly suppressed epithelial-mesenchymal transition (EMT), and high-throughput 16S rRNA pyrosequencing showed that AKK supplementation restored the disordered intestinal microecology in CKD rats. AKK also enhanced the intestinal mucosal barrier function. AKK may regulate the intestinal microecology and reduce renal interstitial fibrosis by enhancing the abundance of probiotics and reducing damage to the intestinal mucosal barrier. CONCLUSION: The results suggest that AKK administration could be a novel therapeutic strategy for treating renal fibrosis and CKD.

Bacteroides plebeius improves muscle wasting in chronic kidney disease by modulating the gut-renal muscle axis.

Chronic kidney disease (CKD) affects approximately 10% of the global population. Muscle atrophy occurs in patients with almost all types of CKD, and the gut microbiome is closely related to protein consumption during chronic renal failure (CRF). This study investigated the effects of Bacteroides plebeius on protein energy consumption in rats with CKD, and our results suggest that Bacteroides plebeius may combat muscle atrophy through the Mystn/ActRIIB/SMAD2 pathway. A total of 5/6 Nx rats were used as a model of muscle wasting in CKD. The rats with muscle wasting were administered Bacteroides plebeius (2 × 108 cfu/0.2 ml) for 8 weeks. The results showed that Bacteroides plebeius administration significantly inhibited muscle wasting in CKD. High-throughput 16 S rRNA pyrosequencing revealed that supplementation with Bacteroides plebeius rescued disturbances in the gut microbiota. Bacteroides plebeius could also enhance the barrier function of the intestinal mucosa. Bacteroides plebeius may modulate the gut microbiome and reduce protein consumption by increasing the abundance of probiotics and reducing damage to the intestinal mucosal barrier. Our findings suggest that Bacteroides plebeius may combat muscle atrophy through the Mystn/ActRIIB/SMAD2 pathway.

Caffeic acid alleviates skeletal muscle atrophy in 5/6 nephrectomy rats through the TLR4/MYD88/NF-kB pathway.

Skeletal muscle atrophy is a common complication of chronic kidney disease (CKD) that affects the quality of life and prognosis of patients. We aimed to investigate the effects and mechanisms of caffeic acid (CA), a natural phenolic compound, on skeletal muscle atrophy in CKD rats. Male Sprague-Dawley rats underwent 5/6 nephrectomy (NPM) and were treated with CA (20, 40, or 80 mg/kg/day) for 10 weeks. The body and muscle weights, renal function, hemoglobin, and albumin were measured. The histological, molecular, and biochemical changes in skeletal muscles were evaluated using hematoxylin-eosin staining, quantitative real-time PCR, malondialdehyde/catalase/superoxide dismutase/glutathione level detection, and enzyme-linked immunosorbent assay. Western blotting and network pharmacology were applied to identify the potential targets and pathways of CA, CKD, and muscle atrophy. The results showed that CA significantly improved NPM-induced muscle-catabolic effects, reduced the expression of muscle atrophy-related proteins (muscle atrophy F-box and muscle RING finger 1) and proinflammatory cytokines (interleukin [IL]-6, tumor necrosis factor-alpha, and IL-1ß), and attenuated muscle oxidative stress. Network pharmacology revealed that CA modulated the response to oxidative stress and nuclear factor kappa B (NF-κB) signaling pathway and that Toll-like receptor 4 (TLR4) was a key target. In vivo experiment confirmed that CA inhibited the TLR4/myeloid differentiation primary response 88 (MYD88)/NF-kB signaling pathway, reduced muscle iron levels, and restored glutathione peroxidase 4 activity, thereby alleviating ferroptosis and inflammation in skeletal muscles. Thus, CA might be a promising therapeutic agent for preventing and treating skeletal muscle atrophy in CKD by modulating the TLR4/MYD88/NF-κB pathway and ferroptosis.

SKP alleviates the ferroptosis in diabetic kidney disease through suppression of HIF-1α/HO-1 pathway based on network pharmacology analysis and experimental validation.

BACKGROUND: Diabetic kidney disease (DKD) represents a microvascular complication of diabetes mellitus. Shenkang Pills (SKP), a traditional Chinese medicine formula, has been widely used in the treatment of DKD and has obvious antioxidant effect. Ferroptosis, a novel mode of cell death due to iron overload, has been shown to be associated with DKD. Nevertheless, the precise effects and underlying mechanisms of SKP on ferroptosis in diabetic kidney disease remain unclear. METHODS: The active components of SKP were retrieved from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. Protein-protein interaction (PPI) network and Herb-ingredient-targets gene network were constructed using Cytoscape. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted utilizing the Metascape system database. Additionally, an in vivo model of DKD induced by Streptozotocin (STZ) was established to further investigate and validate the possible mechanisms underlying the effectiveness of SKP. RESULTS: We retrieved 56 compounds and identified 223 targets of SKP through the TCMSP database. Key targets were ascertained using PPI network analysis. By constructing a Herb-Ingredient-Targets gene network, we isolated the primary active components in SKP that potentially counteract ferroptosis in diabetic kidney disease. KEGG pathway enrichment analysis suggested that SKP has the potential to alleviate ferroptosis through HIF signaling pathway, thereby mitigating renal injury in DKD. In animal experiments, fasting blood glucose, 24 h urine protein, urea nitrogen and serum creatine were measured. The results showed that SKP could improve DKD. Results from animal experiments were also confirmed the efficacy of SKP in alleviating renal fibrosis, oxidative stress and ferroptosis in DKD mice. These effects were accompanied by the significant reductions in renal tissue expression of HIF-1α and HO-1 proteins. The mRNA and immunohistochemistry results were the same as above. CONCLUSIONS: SKP potentially mitigating renal injury in DKD by subduing ferroptosis through the intricacies of the HIF-1α/HO-1 signaling pathway.

Targeting ROCK1 in diabetic kidney disease: Unraveling mesangial fibrosis mechanisms and introducing myricetin as a novel antagonist.

Diabetic kidney disease (DKD) stands as a pressing health challenge, with mesangial cell fibrosis identified as a pivotal hallmark leading to glomerular sclerosis. Gaining a deeper grasp on the molecular dynamics behind this can potentially introduce groundbreaking therapeutic avenues. Recent revelations from studies on ROCK1-deficient mice, which displayed resilience against high-fat diet (HFD)-induced glomerulosclerosis and mitochondrial fragmentation, spurred our hypothesis regarding ROCK1's potential role in mesangial cell fibrosis. Subsequent rigorous experiments corroborated our theory, highlighting the critical role of ROCK1 in orchestrating mesangial cell proliferation and fibrosis, especially in high-glucose settings. Mechanistically, ROCK1 inhibition led to a notable hindrance in the high-glucose-triggered MAPK signaling pathway, particularly emphasizing the ROCK1/ERK/P38 axis. To translate this understanding into potential therapeutic interventions, we embarked on a comprehensive drug screening journey. Leveraging molecular modeling techniques, Myricetin surfaced as an efficacious inhibitor of ROCK1. Dose-dependent in vitro assays substantiated Myricetin's prowess in curtailing mesangial cell proliferation and fibrosis via ROCK1/ERK/P38 pathway. In vivo verifications paralleled these findings, with Myricetin treatment resulting in significant renal function enhancements and diminished DKD pathological markers, all pivoted around the ROCK1/ERK/P38 nexus. These findings not only deepen our comprehension of DKD molecular underpinnings but also elevate ROCK1 to the pedestal of a promising therapeutic beacon. Concurrently, Myricetin is spotlighted as a potent natural contender, heralding a new era in DKD therapeutic design.

Shenshuai Yingyang Jiaonang ameliorates chronic kidney disease-associated muscle atrophy in rats by inhibiting ferroptosis mediated by the HIF-1α/SLC7A11 pathway.

Objective: Shenshuai Yingyang Jiaonang (SSYYJN), a traditional Chinese medicine formula, can ameliorate muscle atrophy associated with chronic kidney disease (CKD). However, its mechanisms of action remain unclear. This study is to investigate the molecular mechanisms involved in the effects of SSYYJN in ameliorating muscle atrophy associated with CKD in rats. Methods: The chemical compounds of SSYYJN were identified by UPLC-Q-Orbitrap HRMS. Considering the dose-response relationship of the identified compounds, male SD rats were randomly divided into Sham, Model, SSYYJN, and α-Keto Acid (KA) groups. Subsequently, we assessed the therapeutic and anti-ferroptotic effects of SSYYJN. Network pharmacology studies were used to predict the molecular mechanism of SSYYJN on ferroptosis and were further verified for accuracy. Results: A total of 42 active compounds were identified from SSYYJN. SSYYJN alleviated muscle atrophy caused by CKD, as evidenced by changes in body weight, serum biochemical indices, mass and histopathology of the skeletal muscle, and the levels of MuRF1. SSYYJN reduced the levels of iron, MDA, and ROS, increased the levels of GSH, NAPDH, and Gpx4. Network pharmacology analysis indicated that SSYYJN exerted anti-ferroptotic effects that were closely related to the HIF-1α signaling pathway. Molecular protein and genetic test results showed that SSYYJN increased HIF-1α protein and increased SLC7A11. Conclusions: SSYYJN attenuates muscle atrophy in CKD by inhibiting ferroptosis through the activation of the HIF-1α/SLC7A11 pathway and might be a promising traditional Chinese medicine for muscle atrophy in CKD.

Effects of Shenkang Pills on Early-Stage Diabetic Nephropathy in db/db Mice via Inhibiting AURKB/RacGAP1/RhoA Signaling Pathway.

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, so there is an urgent need to suppress its development at early stage. Shenkang pills (SKP) are a hospital prescription selected and optimized from effective traditional Chinese medicinal formulas for clinical treatment of DN. In the present study, liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-Q-TOF-MS) and total contents qualification were applied to generate a quality control standard of SKP. For verifying the therapeutic effects of SKP, db/db mice were administered intragastrically with SKP at a human-equivalent dose (1.82 g/kg) for 4 weeks. Moreover, the underlying mechanism of SKP were analyzed by the renal RNA sequencing and network pharmacology. LC-Q-TOF-MS identified 46 compounds in SKP. The total polysaccharide and organic acid content in SKP were 4.60 and 0.11 mg/ml, respectively, while the total flavonoid, saponin, and protein content were 0.25, 0.31, and 0.42 mg/ml, respectively. Treatment of SKP significantly reduced fasting blood glucose, improved renal function, and ameliorated glomerulosclerosis and focal foot processes effacement in db/db mice. In addition, SKP protected podocytes from injury by increasing nephrin and podocin expression. Furthermore, transcriptome analyses revealed that 430 and 288 genes were up and down-regulated in mice treated with SKP, relative to untreated controls. Gene ontology enrichment analysis revealed that the differentially expressed genes mainly involved in modulation of cell division and chromosome segregation. Weighted gene co-expression network analysis and network pharmacology analysis indicated that aurora kinase B (AURKB), Rac GTPase activating protein 1 (RacGAP1) and SHC binding, and spindle associated 1 (shcbp1) might be the core targets of SKP. This protein and Ras homolog family member A (RhoA) were found overexpression in db/db mice, but significantly decreased with SKP treatment. We conclude that SKP can effectively treat early-stage DN and improve renal podocyte dysfunction. The mechanism may involve down-regulation of the AURKB/RacGAP1/RhoA pathway.

Gut Commensal Fungi Protect Against Acetaminophen-Induced Hepatotoxicity by Reducing Cyp2a5 Expression in Mice.

Background and Aims: Drug-induced liver injury (DILI) is a common cause of acute liver failure and represents a significant global public health problem. When discussing the gut-liver axis, although a great deal of research has focused on the role of gut microbiota in regulating the progression of DILI, the gut commensal fungal component has not yet been functionally identified. Methods: Mice were pretreated with fluconazole (FC) to deplete the gut commensal fungi and were then subject to acetaminophen (APAP) gavage. In addition, transcriptome sequencing was performed to identify differentially expressed genes (DEGs) between control and fluconazole-pretreated groups of the mice challenged with APAP. Results: Gut commensal fungi ablation through fluconazole pretreatment predisposed mice to APAP-induced hepatotoxicity, characterized by elevated serum liver enzyme levels and more severe centrilobular necrosis, which appears to be caused by robust inflammation and oxidative stress. The 16S rDNA sequencing results indicated that Akkermansia muciniphila abundance had significantly decreased in gut fungi-depleted mice, whereas increased abundance of Helicobacter rodentium was observed. The gene interaction network between DEGs identified by the transcriptome sequencing highlighted a significant enrichment of Cyp2a5 in the liver of APAP-treated mice that were preadministrated with fluconazole. Pharmacological inhibition of Cyp2a5 by 8-methoxypsoralen (8-MOP) could significantly attenuate hepatic inflammation and oxidative stress in mice, thereby conferring resistance to acute liver injury caused by APAP administration. Conclusion: Our data highlighted the significance of gut commensal fungi in hepatic inflammation and oxidative stress of APAP mice, shedding light on promising therapeutic strategies targeting Cyp2a5 for DILI treatment.

High-dose vitamin D3 supplementation ameliorates renal fibrosis by vitamin D receptor activation and inhibiting TGF-ß1/Smad3 signaling pathway in 5/6 nephrectomized rats.

Renal fibrosis is the pathological consequence of progressive chronic kidney disease. Although it has been reported that vitamin D3 exerts antifibrotic effects, the underlying mechanisms remain unclear. This study is aimed at investigating the effects and molecular mechanisms in high-dose vitamin D3 treatment on renal fibrosis. A model of chronic kidney disease was established by 5/6 nephrectomy in rats characterised by high levels of serum creatine, urea nitrogen, and urinary protein. Serum 25-dihydroxyvitamin D3, calcium and parathormone levels were measured to evaluate vitamin D levels. Hematoxylin and eosin, periodic acid Schiff and Mallory's Trichrome staining were used to evaluate histopathological changes in rats. Moreover, the expression of vimentin, collagen I, α-smooth muscle actin and E-cadherin were analyzed at molecular and histopathological levels. Our results showed that exposure to vitamin D3 decreased the levels of serum creatine, urea nitrogen and urine protein and restored the homeostasis of calcium and parathormone. Vitamin D3 also downregulated the expression of vimentin, collagen I and α-smooth muscle actin and attenuated renal fibrosis and epithelial to mesenchymal transition in the kidney. Importantly, vitamin D3 treatment increased the expression of the vitamin D receptor and inhibited Transforming growth factor-ß1 (TGF-ß1)/Smad3 signaling pathway in rats kidneys with chronic kidney disease. Mechanistically, the upregulation of TGF-ß1 and phosphorylation of Smad3 induced by vitamin D3 was reversed by activation of the vitamin D receptor. Our findings indicated that vitamin D3 is a potential antifibrotic drug in chronic kidney disease via the vitmin D receptor and inhibiting TGF-ß1/Smad3 signaling pathway.

Chemical profiling of Houttuynia cordata Thunb. by UPLC-Q-TOF-MS and analysis of its antioxidant activity in C2C12 cells.

Houttuynia cordata Thunb. ("Yu-Xing-Cao"), a traditional Chinese medicinal herb, has long been used to treat various diseases. However, detailed information regarding the chemical constituents of H. cordata aqueous extract is lacking, and the molecular basis of its beneficial effects on muscle is unknown. To investigate these points, in this study, we used ultra-performance liquid chromatography coupled with quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) in positive and negative ion modes to profile and identify the major constituents of H. cordata water extract. A total of 63 peaks were identified based on mass and fragmentation characteristics, including 29 organic acids and their glycosides, 17 flavonoids, 7 volatiles, 4 pyrimidine and purine derivatives, 2 alkaloids, 2 amino acids, 1 isovanillin, and 1 coumarin. The total flavonoid and polyphenol contents of the extract were 4.77 and 139.15 mg/mL, respectively, by ultraviolet spectrophotometry. The cytoprotective activity of H. cordata aqueous extract was evaluated using C2C12 cells treated with tumor necrosis factor (TNF)-α to induce oxidative challenge. The TNF-α induced decrease in cell viability was reversed by treatment for 48 h with the extract; moreover, superoxide dismutase activity was increased while reactive oxygen species level was decreased. These results provide molecular-level evidence for the antioxidant effect of H. cordata extract and highlight its therapeutic potential for the treatment of muscle injury or diseases caused by oxidative stress.