Licorice Extracts Attenuate Nephrotoxicity Induced by Brucine Through Suppression of Mitochondria Apoptotic Pathway and STAT3 Activation

Involvement of MicroRNA-27a-3p in the Licorice-Induced Alteration of Cd28 Expression in Mice

Licorice has previously been shown to affect gene expression in cells; however, the underlying mechanisms remain to be clarified. We analyzed the microRNA expression profile of serum from mice treated by gavage with licorice decoction, and obtained 11 differentially expressed microRNAs (DEmiRNAs). We also screened differentially expressed genes (DEgenes) based on RNA-Seq data, and 271 common genes were identified by intersection analysis of the predicted target genes of 11 DEmiRNAs and the DEgenes. The miRNA–gene network showed that most of the hub genes were immune-related. KEGG enrichment analysis of the 271 genes identified three significant pathways, and the 21 genes involved in these three pathways, and the 11 DEmiRNAs, were constructed into a miRNA pathway–target gene network, in which mmu-miR-27a-3p stood out. Compared to ImmPort, there were 13 immune genes within the above group of 21 genes, and three intersected with the mmu-miR-27a-3p predicted target genes, Cd28, Grap2 and Cxcl12, of which the expression of Cd28 changed most significantly. We confirmed the regulation of Cd28 by mmu-miR-27a-3p using a dual-luciferase assay, and further confirmed that overexpression of mmu-miR-27a-3p could significantly downregulate the expression of Cd28 in lymphocytes. These results indicate that mmu-miR-27a-3p could be involved in the licorice-mediated regulation of the expression of Cd28 in mice.

Brucine restores sodium nitroprusside-induced chondrocyte dysfunction by suppressing the GSK-3β/β-catenin pathway

The dysfunction of chondrocytes is thought to play a role in the initiation and progression of osteoarthritis (OA). Brucine possesses wide pharmacological activities. But the protective mechanism of the brucine on chondrocytes remains unclear. This study is aimed to determine the therapeutic effects of brucine on the mouse chondrocyte OA model by sodium nitroprusside (SNP). The primary chondrocytes were obtained from the knee articular cartilage of a healthy suckling mouse donor. The cultured chondrocytes were divided into the control group, SNP group, brucine group, brucine-SNP group, brucine-SNP-GSK-3β antagonist group (brucine-SNP- group), and brucine-SNP-GSK-3β agonist group (brucine-SNP-GSK-3β+ group). After 24 h, the chondrocytes from different treated groups were collected to detect chondrocyte proliferation and ultrastructure, regulation factors, apoptosis, oxidative stress, and GSK-3β/β-catenin pathway. Compared to the SNP group, chondrocyte proliferation, and regulation factors were promoted, and chondrocyte apoptosis, oxidative stress, and the GSK-3β/β-catenin pathway were inhibited by brucine. It indicates that the adverse effect of SNP is reversed by the brucine on the chondrocyte. Compared to the brucine-SNP group, the effect of brucine on the chondrocyte proliferation, regulation factothe apoptosis, and oxidative stress were promoted by the GSK-3β antagonist. It indicates that the chondrocyte is protected agairucine through buying the GSK-3β/β-catenin pathway.

Loss of RTN3 phenocopies chronic kidney disease and results in activation of the IGF2-JAK2 pathway in proximal tubular epithelial cells

Reticulon 3 (RTN3) is an endoplasmic reticulum protein that has previously been shown to play roles in neurodegenerative diseases, but little is known about its function in the kidneys. The aim of the present study was to clarify the roles of RTN3 in chronic kidney disease (CKD) and kidney fibrosis. In this study, RTN3 levels were measured in kidney tissues from healthy controls and CKD or kidney fibrosis patients. An RTN3-null mouse model was generated to explore the pathophysiological roles of RTN3 in the kidneys. The underlying mechanisms were studied in primary proximal tubular epithelial cells and HEK293 cells in vitro. The results showed that (1) a reduction in RTN3 in mice induces CKD and kidney fibrosis; (2) decreased RTN3 expression is found in patients with CKD; (3) RTN3 plays critical roles in regulating collagen biosynthesis and mitochondrial function; and (4) mechanistically, RTN3 regulates these phenotypes by interacting with GC-Rich Promoter Binding Protein 1 (GPBP1), which activates the IGF2-JAK2-STAT3 pathway. Our study indicates that RTN3 might play crucial roles in CKD and kidney fibrosis and that a reduction in RTN3 in the kidneys might be a risk factor for CKD and kidney fibrosis.

A protein (RTN3) known to be involved in neurodegenerative diseases may play a causative role in kidney fibrosis or scarring, and chronic kidney disease (CKD). An estimated 20% of CKD cases may have genetic causes and identifying the genes involved may help find better treatments. Ri-Qiang Yan at the University of Connecticut Health, Farmington, USA, and Rong Xian at Central South University, China, noticed that mice in which the gene coding for RTN3 was inactivated had kidney fibrosis. The researchers showed that RTN3 levels were also lower in kidney tissues of patients with CKD than in healthy individuals and that RTN3 levels were inversely proportional to disease progression. Further investigation showed that decreased RTN3 caused extra collagen deposition and misshapen mitochondria, the cellular powerhouses, in the kidney. These results identify a potential novel risk factor for CKD.

Nephroprotective activity of Aframomum melegueta seeds extract against diclofenac-induced acute kidney injury: A mechanistic study

ETHNOPHARMACOLOGICAL RELEVANCE

In Africa, Aframomum species have been traditionally used to treat illnesses such as inflammation, hypertension, diarrhea, stomachache and fever. Moreover, Aframomum melegueta seed extracts (AMSE) are used in traditional medicine to relieve stomachaches and inflammatory diseases.

AIM

Chronic administration of diclofenac (DIC) has been reported to cause acute kidney injury (AKI), which is a serious health condition. The nephroprotective effect of AMSE is yet to be elucidated. Accordingly, this study aims to investigate the phytoconstituents of standardized AMSE, evaluate its nephroprotective effects against DIC-induced AKI in rats, and elaborate its underlying molecular mechanisms.

MATERIALS AND METHODS

The quantitative estimation of major AMSE constituents and profiling of its secondary metabolites were conducted via RP-HPLC and LC-ESI/Triple TOF/MS, respectively. Next, DIC (50 mg/kg)-induced AKI was achieved in Sprague-Dawley rats and DIC-challenged rats were administered AMSE (100 and 200 mg/kg) orally. All treatments were administered for five consecutive days. Blood samples were collected and the sera were used for estimating creatinine, urea and, kidney injury molecule (KIM)-1 levels. Kidney specimens were histopathologically assessed and immunohistochemically examined for c-Myc expression. A portion of the kidney tissue was homogenized and examined for levels of oxidative stress markers (MDA and GSH). Heme oxygenase (HO)-1, TNF-α, IL-6, Bax, Bcl2 and caspase-3 renal levels were quantified by ELISA. Moreover, the protein expression levels of NF-ҡB p65 was quantified using Western blot analysis, whereas mRNA expression levels of AMPK, SIRT-1, nuclear factor erythroid-2-related factor (Nrf2) and STAT3 were detected using qRT-PCR in the remaining kidney tissues.

RESULTS

Standardized AMSE was shown to primarily contain 6-gingerol, 6-shogaol and 6-paradol among the 73 compounds that were detected via LC-ESI/Triple TOF/MS including phenolic acids, hydroxyphenylalkanes, diarylheptanoids and fatty acids. Relative to DIC-intoxicated rats, AMSE modulated serum creatinine, urea, KIM-1, renal MDA, TNF-α, IL-6, Bax, and caspase-3 levels. AMSE has also improved renal tissue architecture, enhanced GSH and HO-1 levels, and upregulated renal Nrf2, AMPK, and SIRT-1 mRNA expression levels. Furthermore, AMSE suppressed NF-ҡB p65 protein and STAT3 mRNA expression, and further reduced c-Myc immunohistochemical expression in renal tissues. Overall, our findings revealed that AMSE counteracted DIC-induced AKI via its antioxidant, anti-inflammatory, and antiapoptotic activities. Moreover, AMSE activated Nrf2/HO1 and AMPK/SIRT1, and inhibited NF-ҡB/STAT3 signaling pathways. Therefore, AMSE is a promising agent for inhibiting DIC-induced nephrotoxicity.

18β-Glycyrrhetinic Acid Improves Cardiac Diastolic Function by Attenuating Intracellular Calcium Overload

Ranolazine, a late sodium current inhibitor, has been demonstrated to be effective on heart failure. 18β-glycyrrhetinic acid (18β-GA) has the similar inhibitory effect on late sodium currents. However, its effect on diastolic function is still unknown. This study aimed to determine whether 18β-GA can improve the diastolic function and to explore the underlying mechanisms. Eighty male Sprague Dawley (SD) rats of Langendorff model were randomly divided into the following groups: group A, normal cardiac perfusion group; group B, ischemia-reperfusion group; group C, ischemia-reperfusion with anemoniasulcata toxin II (ATX-II); group D, ranolazine group; and group E, 18β-GA group with four different concentrations. Furthermore, a pressure-overloaded rat model induced by trans-aortic constriction (TAC) was established. Echocardiography and hemodynamics were used to evaluate diastolic function at 14th day after TAC. Changes of free intracellular calcium (Ca²⁺) concentration was indirectly detected by laser scanning confocal microscope to confirm the inhibition of late sodium currents. With the intervention of ATX-II on ischemia reperfusion injury group, 5 µmol/L ranolazine, and 5, 10, 20, 40 µmol/L 18β-GA could improve ATX-II-induced cardiac diastolic dysfunction. 630 mg/kg glycyrrhizin tablets could improve cardiac diastolic function in the pressure-overloaded rats. 18β-GA and ranolazine had similar effects on reducing the free calcium in cardiomyocytes. The study demonstrates that 18β-GA and glycyrrhizin could improve diastolic dysfunction induced by ischemia-reperfusion injury in Langendorff-perfused rat hearts and pressure-overloaded rats. The mechanism may be attributed to the inhibition of enhanced late sodium currents.

Research Progress on Anti-Inflammatory Effects and Mechanisms of Alkaloids from Chinese Medical Herbs

As the spectrum of diseases keeps changing and life pace keeps going faster, the probability and frequency of diseases caused by human inflammatory reactions also keep increasing. How to develop effective anti-inflammatory drugs has become the hotspot of researches. It has been found that alkaloids from Chinese medical herbs have anti-inflammatory, analgesic, antitumor, anticonvulsant, diuretic, and antiarrhythmic effects, among which the anti-inflammatory effect is very prominent and commonly used in the treatment of rheumatoid arthritis, ankylosing spondylitis, and other rheumatic immune diseases, but its mechanism of action has not been well explained. Based on this, this paper will classify alkaloids according to structural types and review the plant sources, applicable diseases, and anti-inflammatory mechanisms of 16 kinds of alkaloids commonly used in clinical treatment, such as berberine, tetrandrine, and stephanine, with the aim of providing a reference for drug researches and clinical applications.