ERK and p38 MAPK inhibition controls NF-E2 degradation and profibrotic signaling in renal proximal tubule cells

Analysis of the potential biological mechanisms of geniposide on renal fibrosis by network pharmacology and experimental verification

BACKGROUND

Renal fibrosis is crucial in the progression of chronic kidney disease (CKD) to end-stage renal failure. Geniposide, an iridoid glycoside, has shown therapeutic potential in acute kidney injury, diabetic nephropathy, and atherosclerosis. The aim of this study was to investigate the role of geniposide in renal fibrosis and its underlying mechanisms.

METHODS

The network pharmacology and molecular docking methods were used to identify potential targets and pathways of geniposide for treating renal fibrosis. In vivo, the unilateral ureteral obstruction (UUO) mouse model was treated with geniposide. In vitro, TGF-β1-stimulated human renal tubular epithelial (HK-2) cells were applied for validation. HE, PAS, Masson, and immunohistochemistry staining were performed to evaluate its effects on the kidneys of UUO mice. RT-qPCR and western blotting were used to detect the expression of hub genes and signaling pathways.

RESULTS

101 overlapping genes were identified, with the top 10 including AKT1, MMP9, GAPDH, BCL2, TNF, CASP3, SRC, EGFR, IL-1β, and STAT1. GO analysis suggested that these key targets were mainly involved in cell proliferation and apoptosis. KEGG analysis revealed that the PI3K/AKT, MAPK, and Rap1 signaling pathways were associated with geniposide against renal fibrosis. Molecular docking suggested a strong binding affinity of geniposide to the hub genes. In vivo experiments showed that geniposide ameliorated kidney injury and fibrosis, and inhibited the mRNA levels of AKT1, MMP9, BCL2, and TNF. In addition, geniposide inhibited the activation of the PI3K/AKT signaling pathway, thereby suppressing renal fibrosis in UUO mice and TGF-β1-induced HK-2 cells.

CONCLUSIONS

Geniposide can attenuate renal fibrosis by inhibiting the PI3K/AKT pathway, suggesting its potential as a therapeutic agent for renal fibrosis.

PPARβ/δ prevents inflammation and fibrosis during diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a specific type of myocardial disease that often develops in patients suffering from diabetes, which has become the foremost cause of death among them. It is an insidious multifactorial disease caused by complex and partially unknown mechanisms that include metabolic dysregulation, local inflammation, fibrosis, and cardiomyocyte apoptosis. Despite its severity and poor prognosis, it often goes undiagnosed, and there are currently no approved specific drugs to prevent or even treat it. Peroxisome proliferator-activated receptor (PPAR)β/δ is a key metabolic regulator that has been proposed as a potential target for DCM due to its pleiotropic anti-inflammatory properties. Diabetes was induced by multiple low-dose streptozotocin (STZ) administration in wild-type and PPARβ/δ knockout male mice treated with the PPARβ/δ agonist GW0742 or vehicle. Human cardiomyocytes (AC16) and mouse atrial myocytes (HL-1) exposed to hyperglycemia and treated with PPARβ/δ agonists were also used. PPARβ/δ deletion in mice negatively impacted cardiac morphology and function, which was accompanied by interstitial fibrosis and structural remodeling of the heart. This phenotype was further exacerbated in knockout diabetic mice. At the molecular level, PPARβ/δ suppression resulted in increased expression of pro-inflammatory and pro-fibrotic markers. Some of these markers were also induced by diabetes in wild-type mice and were exacerbated in diabetic knockout mice. The activity of the transcription factors nuclear factor κB (NF-κB) and activator protein-1 (AP-1) correlated with most of these changes. Remarkably, PPARβ/δ activation partially prevented inflammation and fibrosis in the heart, as well as cardiac atrophy, induced during diabetes in mice, and also in cultured cardiomyocytes exposed to hyperglycemia. Finally, our results suggest that the beneficial effects of PPARβ/δ activation are mediated by the inhibition of mitogen-activated protein kinases (MAPK) activity and subsequent downregulation of the transcriptional activities of NF-κB and AP-1. Overall, the data suggest that PPARβ/δ agonists might be useful in preventing inflammation and fibrosis progression in DCM.

STAP2 promotes the progression of renal fibrosis via HSP27

BACKGROUND

Renal fibrosis is a key process in the progression from acute kidney injury (AKI) to chronic kidney disease (CKD), while the intricate mechanisms of renal fibrosis remain obscure. While the signal-transducing adaptor protein 2 (STAP2) was well-studied for its notable function in inflammation and immune-related disorders, its specific implication in renal fibrosis remains unclear. This study assessed the mechanism by which STAP2 could promote the progression of renal fibrosis.

METHODS

The expression level of STAP2 in fibrotic human samples, murine fibrosis models, and cellular fibrosis models was measured, respectively. Subsequently, immunoprecipitation (IP), mass spectrometry, and RNA sequencing (RNA-seq) were employed to identify HSP27 as an interacting protein and the PI3K-AKT signaling pathway. STAP2 was thereafter knocked down or overexpressed in both in vivo and in vitro models to assess the expression levels of pathway-related and fibrosis-related proteins. Finally, the important role of STAP2 in the fibrosis process in animal models induced by ischemia-reperfusion injury (IRI) and cisplatin was validated.

RESULTS

Functionally, in vivo assays demonstrated that the genetic knockout of STAP2 could remarkably mitigate epithelial-mesenchymal transition (EMT), diminish inflammatory cell infiltration, and reduce collagen deposition in mice with renal fibrosis. Conversely, in vitro assays employing STAP2-overexpressing cell models exacerbated the expression levels of fibrosis markers. The outcomes uncovered a potential mechanism by which STAP2 could modulate renal fibrosis through its impact on the expression level of phosphorylated HSP27, as well as modulating the PI3K/AKT signaling pathway.

CONCLUSIONS

This comprehensive investigation delineated the noticeable function of STAP2 in the advancement of renal fibrosis, and the outcomes might contribute to the development of targeted therapies concentrated on STAP2 to mitigate renal fibrosis.

Integrating network pharmacology and experimental validation to decipher the mechanism of the Chinese herbal prescription modified Shen-Yan-Fang-Shuai formula in treating diabetic nephropathy

CONTEXT

Diabetic nephropathy (DN) is the main cause of end-stage renal disease. Modified Shen-Yan-Fang-Shuai formula (M-SYFSF) has excellent clinical efficacy in treating diabetic kidney disease. However, the potential mechanism of M-SYFSF remains unknown.

OBJECTIVE

To investigate the mechanism of M-SYFSF against DN by network pharmacological analysis and biological experiments.

MATERIALS AND METHODS

Utilizing a web-based pharmacology database, the potential mechanisms of M-SYFSF against DN were identified. In vivo experiments, male SD rats were injected with streptozotocin (50 mg/kg) and got uninephrectomy to construct a model of DN. M-SYFSF (11.34 g/kg/d) was gavaged once per day for 12 weeks after model establishment. In vitro experiments, human proximal tubular cells (HK-2) were performed with advanced glycation end-products (AGEs) (100 μg/mL), then intervened with M-SYFSF freeze-dried powder. Pathological staining, WB, IHC, ELISA were conducted to explore the mechanism of M-SYFSF against DN.

RESULTS

Network pharmacological analysis showed that MAPK pathway was the potential pathway. Results showed that compared with the Model group, M-SYFSF significantly reduced 24h urine albumin, UACR, and serum creatinine levels (54.90 ± 26.67 vs. 111.78 ± 4.28, 8.87 ± 1.69 vs. 53.94 ± 16.01, 11.56 ± 1.70 vs. 118.70 ± 49.57, respectively), and improved renal pathological changes. Furthermore, the intervention of M-SYFSF reduced the expression of pro-inflammatory cytokines and inhibited the activation of MAPK pathway in AGEs-treated HK-2 cells.

DISCUSSION AND CONCLUSION

M-SYFSF is likely to reduce inflammation in DN by inhibiting the MAPK pathway. It provides a theoretical basis for the clinical application of M-SYFSF in the treatment of DN.

E Se tea extract ameliorates CCl4 induced liver fibrosis via regulating Nrf2/NF-κB/TGF-β1/Smad pathway

BACKGROUND

Liver fibrosis is a crucial progress to deteriorate liver disease. E Se tea (ES) is an ethnic herbal tea in China that has various biological activities for human beings. However, the traditional application on the treatment of liver disease is not studied.

PURPOSE

This study is firstly performed to explore the chemical constituents of ES extract together with its anti-hepatic fibrosis effect and potential mechanism on CCl₄ treated mice.

STUDY DESIGN AND METHODS

The chemical constituents of ethanol-aqueous extract from ES (ESE) were analyzed by UPLC-ESI-MS/MS. The anti-hepatic fibrosis effect of ESE was determined by measuring ALT and AST activities, antioxidative indexes, inflammatory cytokines and collagen protein levels on CCl₄ treated mice. Moreover, H&E, Masson staining and immunohistochemical analysis were performed for evaluating the protective effect of ESE on histopathological changes of liver tissues.

RESULTS

UHPLCHRESI-MS/MS analysis showed that the ESE was rich in flavonoids such as phlorizin, phloretin, quercetin and hyperoside. ESE could significantly reduce the plasma AST and ALT activities. The cytokines (IL-6, TNF-α, IL-1β) expressions were inhibited after ESE administration via suppressing NF-κB pathway. In addition, ESE could decrease MDA accumulation for alleviating CCl₄ induced liver oxidative stress via regulating Nrf2 pathway to promote the expressions of antioxidant enzymes (SOD, HO-1, CAT and NQO1). Moreover, ESE could inhibit the expressions of TGF-β1, Smad2, α-SMA, and collagens Ⅰ and III proteins, thereby effectively alleviate the liver fibrosis.

CONCLUSION

This study demonstrated that ESE could alleviate liver fibrosis through enhancing antioxidant and anti-inflammatory abilities by Nrf2/NF-κB pathway and reducing deposition of liver fibrosis via suppressing TGF-β/Smad pathway.

Protective effect of Anneslea fragrans ethanolic extract against CCl4-induced liver injury by inhibiting inflammatory response, oxidative stress and apoptosis

Anneslea Fragrans Wall. (AF) is a medicinal and edible plant distributed in China. Its leaves and bark generally used for the treatments of diarrhea, fever, and liver diseases. While its ethnopharmacological application against liver diseases has not been fully studied. This study was aimed to evaluate the hepatoprotective effect of ethanolic extract from A. fragrans (AFE) on CCl₄ induced liver injury in mice. The results showed that AFE could effectively reduce plasma activities of ALT and AST, increase antioxidant enzymes activities (SOD and CAT) and GSH level, and decrease MDA content in CCl₄ induced mice. AFE effectively decreased the expressions of inflammatory cytokines (IL-1β, IL-6, TNF-α, COX-2 and iNOS), cell apoptosis-related proteins (Bax, caspase-3 and caspase-9) and increased Bcl-2 protein expression via inhibiting MAPK/ERK pathway. Additionally, TUNEL staining, Masson and Sirius red staining, immunohistochemical analyses revealed that AFE could inhibit the CCl₄-induced hepatic fibrosis formation via reducing depositions of α-SMA, collagen I and collagen III. Conclusively, the present study demonstrated that AFE had an hepatoprotective effect by MAPK/ERK pathway to inhibit oxidative stress, inflammatory response and apoptosis in CCl₄-induced liver injury mice, suggesting that AFE might be served as a hepatoprotective ingredient in the prevention and treatment of liver injury.

Dual specificity phosphatase 22 suppresses mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK signaling pathway in diabetic nephropathy

Dual specificity phosphatase 22 (DUSP22) regulates fibrosis and inflammation, which may be implicated in the development of diabetic nephropathy (DN). Hence, the current study aimed to assess the effect of DUSP22 on cell proliferation, apoptosis, fibrosis and inflammation in mouse mesangial cell line (SV40-MES13) under both high glucose (HG) and low glucose (LG) conditions. SV40-MES13 cells were treated with HG and LG, then HG-group cells were transfected with DUSP22 overexpression and control plasmids, meanwhile LG-group cells were transfected with DUSP22 and control siRNAs. Then, cell proliferation using Cell Counting Kit-8, cell apoptosis by TUNEL assay, protein expression using western blotting, inflammatory cytokines using ELISA and RNA using reverse transcription-quantitative PCR were determined. DUSP22 mRNA and protein were decreased in SV40-MES13 cells under the HG condition compared with those under the LG condition. Under the HG condition, DUSP22 overexpression suppressed SV40-MES13 cell proliferation at 48 and 72 h as well as Bcl2, but it facilitated TUNEL-reflected apoptotic rate and cleaved-caspase-3; besides, DUSP22 overexpression restrained proteins of fibronectin 1, collagen I, transforming growth factor beta 1, and their corresponding mRNAs. As to the inflammation, DUSP22 overexpression downregulated TNF-α, IL-1β, IL-6 and IL-12 under the HG condition. By contrast, DUSP22 siRNA promoted SV40-MES13 cell proliferation, fibrosis and inflammation, but attenuated apoptosis in SV40-MES13 cells under the LG condition. Additionally, DUSP22 overexpression inactivated phosphorylated (p)-ERK, p-JNK, and p-P38 in HG-treated SV40-MES13 cells; differently, DUSP22 small interfering RNA facilitated them under the LG condition. In conclusion, DUSP22 suppresses HG-induced mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK pathway, implying its potency in DN treatment.

Melamine induced changes in histopathology of the main organs and transcriptional levels of MAPK signaling genes in kidneys of female mice

Melamine is an important chemical raw material used in industries, which has potential health risks to animals and humans. Current research mainly focuses on the toxic effects of high-dose melamine ingestion. However, there are few reports on whether melamine at the current limited standard dose has adverse effects on various tissues and organs, and whether there are sensitive target genes for risk evaluation. For this, 24 female Kunming mice were fed 0, 1.8-, 3.6-, and 7.2- mg/kg/d melamine via drinking water for consecutive 28 days, respectively. The morphological changes of the ovarian, hepatic, and renal tissues were firstly observed. The results demonstrated that the histopathology of ovary, liver, and especially in kidney had been altered by melamine intake in female. And then, the transcriptional levels of MAPK signaling genes including p38, ERK1, ERK2, JNK1, and JNK2 in kidneys were investigated by real-time PCR. The data showed that ERK1 and p38 mRNAs expressions were up-regulated significantly by melamine, suggesting that ERK1 and p38 transcriptional levels in the kidney might to be considered as candidate targets for lower-dose melamine toxicity. This study not only provides potential targets for the diagnosis and prevention of melamine damage, but also helps to assess the health risks of the current minimum allowable levels of melamine in food and environment.