Baicalin protects against renal interstitial fibrosis in mice by inhibiting the TGF-β/Smad signalling pathway

Baicalin - 2- ethoxyethyl ester alleviates renal fibrosis by inhibiting PI3K/AKT/NF-κB signaling pathway

With the increasing incidence of chronic kidney disease (CKD), the development of safe and effective anti-renal fibrosis drugs is particularly urgent. Recently, Baicalin has been considered to have a renal protective effect, but its bioavailability is too low. Therefore, we synthesized baicalin-2-ethoxyethyl ester (BAE) by esterification of baicalin. We hope that this experiment will demonstrate the anti-renal fibrosis effect of BAE and explain its molecular mechanism. In this study, the chronic kidney injury model of SD rats was established by 5/6 nephrectomy, and BAE was given for 28 days. The results showed that after BAE treatment, the serum creatinine and urea nitrogen levels decreased significantly, and the pathological changes in kidneys were improved. In addition, RNA-seq analysis showed that the mechanism of BAE in relieving renal fibrosis was related to the ECM receptor, PI3K/AKT signaling pathway, and inflammatory reaction. The western blotting analysis confirmed that BAE could inhibit the expression of α-SMA, TGF-β1, p-PI3K, p-AKT, p-IκBα, and NF-κB p65. We found that BAE can inhibit the inflammatory reaction and promote the degradation of the extracellular matrix by inhibiting the activation of the PI3K/AKT/NF-κB pathway, thus alleviating the symptoms of renal fibrosis in 5/6Nx rats, which revealed BAE was a potential compound to relieve renal fibrosis effect.

Antioxidant therapy against TGF-β/SMAD pathway involved in organ fibrosis

Fibrosis refers to excessive build-up of scar tissue and extracellular matrix components in different organs. In recent years, it has been revealed that different cytokines and chemokines, especially Transforming growth factor beta (TGF-β) is involved in the pathogenesis of fibrosis. It has been shown that TGF-β is upregulated in fibrotic tissues, and contributes to fibrosis by mediating pathways that are related to matrix preservation and fibroblasts differentiation. There is no doubt that antioxidants protect against different inflammatory conditions by reversing the effects of nitrogen, oxygen and sulfur-based reactive elements. Oxidative stress has a direct impact on chronic inflammation, and as results, prolonged inflammation ultimately results in fibrosis. Different types of antioxidants, in the forms of vitamins, natural compounds or synthetic ones, have been proven to be beneficial in the protection against fibrotic conditions both in vitro and in vivo. In this study, we reviewed the role of different compounds with antioxidant activity in induction or inhibition of TGF-β/SMAD signalling pathway, with regard to different fibrotic conditions such as gastro-intestinal fibrosis, cardiac fibrosis, pulmonary fibrosis, skin fibrosis, renal fibrosis and also some rare cases of fibrosis, both in animal models and cell lines.

[Qingshen Granules-medicated serum reduces transdifferentiation of NRK-52E cells by miR-23b-5p-mediated activation of the Nrf2 pathway]

OBJECTIVE

TTo investigate the targeted regulation of the Nrf2 pathway by miR-23b-5p in transdifferentiation of rat renal tubular epithelial NRK-52E cells induced by transforming growth factor β1(TGF-β1)and the effect of Qingshen Granulesmedicated serum for alleviating transdifferentiation of NRK-52E cells.

METHODS

NRK-52E cells with TGF-β1-induced transdifferentiation were transfected with miR-23b-5p mimic, miR-23b-5p inhibitor or the negative control(NC)siRNA and then treated with of Qingshen Granules-medicated serum.CCK8 assay was used to detectthe changes in viability of NRK-52E cells.The targeting relationship between miR-23b-5p and Nrf2 was verified using a dual luciferase reporter gene assay.The expressions of Nrf2, Keap1 and α-SMA mRNAs and proteins in the treated cells were detected with RT-qPCR and Western blotting, and ROS production in the cells was detected with flow cytometry.

RESULTS

Transfection of NRK-52E cells with miR-23b-5p mimic significantly increased the expression of Nrf2 mRNA, while inhibition of miR-23b-5p obviously lowered Nrf2 mRNA in the cells.Rno-miR-23b-5p significantly down-regulated the luciferase activity of Rno-Nrf2-wt but not that of Rno-Nrf2-mu(P<0.05).Treatment with TGF-β1 significantly decreased the expressions of miR-23b-5p and Nrf2 and increased the expressions of Keap1, α-SMA and ROS in NRK-52E cells(P<0.05), and these changes were obviously ameliorated by treatment with 20% Qingshen Granules-medicated serum for 24 h.Transfection of the cells with miR-23b-mimic significantly decreased the expressions of Keap1, α-SMA and ROS(P<0.05), which were further decreased by treatment with the medicated serum(P<0.05).

CONCLUSION

Qingshen Granules-medicated serum reduces transdifferentiation of NRK-52E cells via miR-23b-5pmediated activation of the Nrf2 pathway.

Enhanced fatty acid oxidation through metformin and baicalin as therapy for COVID-19 and associated inflammatory states in lung and kidney

Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (COVID-19) pandemic. It is the final outcome of the acute respiratory distress syndrome (ARDS), characterized by an initial exacerbated inflammatory response, metabolic derangement and ultimate tissue scarring. A positive balance of cellular energy may result crucial for the recovery of clinical COVID-19. Hence, we asked if two key pathways involved in cellular energy generation, AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling and fatty acid oxidation (FAO) could be beneficial. We tested the drugs metformin (AMPK activator) and baicalin (CPT1A activator) in different experimental models mimicking COVID-19 associated inflammation in lung and kidney. We also studied two different cohorts of COVID-19 patients that had been previously treated with metformin. These drugs ameliorated lung damage in an ARDS animal model, while activation of AMPK/ACC signaling increased mitochondrial function and decreased TGF-β-induced fibrosis, apoptosis and inflammation markers in lung epithelial cells. Similar results were observed with two indole derivatives, IND6 and IND8 with AMPK activating capacity. Consistently, a reduced time of hospitalization and need of intensive care was observed in COVID-19 patients previously exposed to metformin. Baicalin also mitigated the activation of pro-inflammatory bone marrow-derived macrophages (BMDMs) and reduced kidney fibrosis in two animal models of kidney injury, another key target of COVID-19. In human epithelial lung and kidney cells, both drugs improved mitochondrial function and prevented TGF-β-induced renal epithelial cell dedifferentiation. Our results support that favoring cellular energy production through enhanced FAO may prove useful in the prevention of COVID-19-induced lung and renal damage.

Simultaneous determination of multiple constituents, serum composition, and tissue distribution of Qingshen granule using ultra-high performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrometry

Qingshen granule, composed of 14 herbal drugs, is primarily used as the assistant therapy for chronic kidney disease. Qingshen granule chemical composition was complex, but its chemical constituents and the pharmacodynamic material basis remain unreported. Ultra-high-performance liquid chromatography (UHPLC)-quadrupole-orbitrap high-resolution mass spectrometry was applied to recognize the chemical constituents of Qingshen granule. The analysis was performed using the ACQUITY UHPLC BEH C18 column (2.1 × 50 mm, 1.7 μm) with acetonitrile-0.1% formic acid as the mobile phase for gradient elution. The data were collected using heated electrospray ionization in positive and negative ion modes. This study successfully applied the UPHLC-quadrupole-orbitrap high-resolution mass spectrometry technique with the Compound Discoverer 3.3 platform to analyze Qingshen granule chemical composition. A total of 127 and 42 chemical components were identified in Qingshen granule in vitro and in vivo, respectively. In the tissue distribution of Qingshen granule, 9, 10, 11, 10, and 18 prototype components were detected in the heart, liver, spleen, lungs, and kidneys, respectively. Qingshen granule chemical constituents were characterized rapidly for the first time in this study, laying a foundation for further research on the substance basis and quality control of Qingshen granule in treating chronic kidney disease.

Isoliensinine Attenuates Renal Fibrosis and Inhibits TGF-β1/Smad2/3 Signaling Pathway in Spontaneously Hypertensive Rats

Purpose

This study aimed to investigate the molecular mechanisms of isoliensinine, a kind of bibenzyl isoquinoline alkaloid which isolated from a TCM named Lotus Plumule (Nelumbo nucifera Gaertn), in treating renal interstitial fibrosis (RIF) by using RNA sequencing, KEGG analysis and in vivo experimental approaches.

Methods

Spontaneous hypertension rats (SHRs) were randomly assigned into five groups, consisting of SHR, SHR+Isoliensinine-L (2.5 mg/kg/day), SHR+Isoliensinine-M (5 mg/kg/day), SHR+Isoliensinine-H (10 mg/kg/day), and SHR+Valsartan (10 mg/kg/day) groups (n = 6 for each group). A control group of Wistar Kyoto rats (n = 6) was also included. Rats were treated intragastrically with isoliensinine, valsartan, or double-distilled water of equal volume for 10 weeks. To examine the therapeutic impact on hypertensive renal injury, fibrosis, and its underlying mechanisms, multiple techniques were employed, including hematoxylin and eosin staining, Masson trichrome staining, RNA sequencing, gene ontology (GO) function and pathway enrichment analysis and immunohistochemistry.

Results

Resultantly, the use of isoliensinine at different concentrations or valsartan showed significant improvement in renal pathological injury in SHRs. RNA sequencing and KEGG analysis uncovered 583 differentially expressed transcripts and pathways enriched in collagen formation and ECM-receptor interaction after treatment with isoliensinine. There was also a reduction in the increase of collagen and upregulation of collagen I & III, TGF-β1, p-Smad2, and p-Smad3 in the renal tissue of SHRs. Thus, isoliensinine ameliorated renal injury and collagen deposition in hypertensive rats, and inhibiting the activation of the TGF-β1/Smad2/3 pathway might be one of the underlying mechanisms.

Conclusion

This study showed that treatment with isoliensinine effectively reduced the renal injury and fibrosis in SHRs. In addition, isoliensinine inhibited the TGF-β1/Smad2/3 signaling in-vivo. These findings provided strong evidence for the therapeutic benefits of isoliensinine in combating renal injury and fibrosis.

Research progress on the mechanism of renal interstitial fibrosis in obstructive nephropathy

Renal fibrosis is a common result for various chronic kidney diseases developing to the end stage. It is a pathological process characterized by the destruction of normal kidney structure and the subsequent replacement with fibrous tissue, which primarily involves fibroblast proliferation and extracellular matrix deposition. Obstruction is a common cause of renal fibrosis, and obstructive renal fibrosis is a common disease in urology. Obstructive renal fibrosis, characterized by its insidious onset, is the result of a complex interplay of multiple factors. These factors encompass renal tubular epithelial cell injury, the presence of a hypoxic microenvironment in affected kidney tissue, inflammatory cell infiltration, release of inflammatory mediators, and the release of renal fibrosis growth factors, among others. This paper reviews the research progress on the mechanism and treatment of renal interstitial fibrosis.

Significance of methylation-related genes in diagnosis and subtype classification of renal interstitial fibrosis

BACKGROUND

RNA methylation modifications, such as N1-methyladenosine/N6-methyladenosine /N5-methylcytosine (m¹A/m⁶A/m⁵C), are the most common RNA modifications and are crucial for a number of biological processes. Nonetheless, the role of RNA methylation modifications of m¹A/m⁶A/m⁵C in the pathogenesis of renal interstitial fibrosis (RIF) remains incompletely understood.

METHODS

Firstly, we downloaded 2 expression datasets from the GEO database, namely GSE22459 and GSE76882. In a differential analysis of these datasets between patients with and without RIF, we selected 33 methylation-related genes (MRGs). We then applied a PPI network, LASSO analysis, SVM-RFE algorithm, and RF algorithm to identify key MRGs.

RESULTS

We eventually obtained five candidate MRGs (WTAP, ALKBH5, YTHDF2, RBMX, and ELAVL1) to forecast the risk of RIF. We created a nomogram model derived from five key MRGs, which revealed that the nomogram model may be advantageous to patients. Based on the selected five significant MRGs, patients with RIF were classified into two MRG patterns using consensus clustering, and the correlation between the five MRGs, the two MRG patterns, and the genetic pattern with immune cell infiltration was shown. Moreover, we conducted GO and KEGG analyses on 768 DEGs between MRG clusters A and B to look into their different involvement in RIF. To measure the MRG patterns, a PCA algorithm was developed to determine MRG scores for each sample. The MRG scores of the patients in cluster B were higher than those in cluster A.

CONCLUSIONS

Ultimately, we concluded that cluster A in the two MRG patterns identified on these five key m¹A/m⁶A/m⁵C regulators may be associated with RIF.

Baicalin-Current Trends in Detection Methods and Health-Promoting Properties

Baicalin (7-D-glucuronic acid-5,6-dihydroxyflavone) belongs to natural flavonoids extracted from the roots of Scutellaria baicalensis, the plant used in traditional Chinese medicine. It has been proven that baicalin has various pharmacological activities, such as antioxidant, anti-inflammatory, anticancer, antibacterial, and anti-apoptotic ones. However, it is essential not only to determine the medical usefulness of baicalin, but also to find and develop the most effective methods for its extraction and detection. Therefore, the aim of this review was to summarize the current methods of detection and identification of baicalin and to present the medical applications of baicalin and the underlying mechanisms of its action. Based on the review of the latest literature, it can be concluded that liquid chromatography alone or together with mass spectrometry is the most commonly used method for the determination of baicalin. Recently, also new electrochemical methods have been established, e.g., biosensors with fluorescence, which have better detection limits, sensitivity, and selectivity.