Functional Metabolomics Analysis Elucidating the Metabolic Biomarker and Key Pathway Change Associated With the Chronic Glomerulonephritis and Revealing Action Mechanism of Rhein

Serum and urine metabolomic biomarkers for predicting prognosis in patients with immunoglobulin A nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most prevalent form of glomerulonephritis worldwide. Prediction of disease progression in IgAN can help to provide individualized treatment based on accurate risk stratification.

METHODS

We performed proton nuclear magnetic resonance-based metabolomics analyses of serum and urine samples from healthy controls, non-progressor (NP), and progressor (P) groups to identify metabolic profiles of IgAN disease progression. Metabolites that were significantly different between the NP and P groups were selected for pathway analysis. Subsequently, we analyzed multivariate area under the receiver operating characteristic (ROC) curves to evaluate the predictive power of metabolites associated with IgAN progression.

RESULTS

We observed several distinct metabolic fingerprints of the P group involving the following metabolic pathways: glycolipid metabolism; valine, leucine, and isoleucine biosynthesis; aminoacyl-transfer RNA biosynthesis; glycine, serine, and threonine metabolism; and glyoxylate and dicarboxylate metabolism. In multivariate ROC analyses, the combinations of serum glycerol, threonine, and proteinuria (area under the curve [AUC], 0.923; 95% confidence interval [CI], 0.667-1.000) and of urinary leucine, valine, and proteinuria (AUC, 0.912; 95% CI, 0.667-1.000) showed the highest discriminatory ability to predict IgAN disease progression.

CONCLUSION

This study identified serum and urine metabolites profiles that can aid in the identification of progressive IgAN and proposed perturbed metabolic pathways associated with the identified metabolites.

High-Throughput Screening of Natural Product and Synthetic Molecule Libraries for Antibacterial Drug Discovery

Due to the continued emergence of resistance and a lack of new and promising antibiotics, bacterial infection has become a major public threat. High-throughput screening (HTS) allows rapid screening of a large collection of molecules for bioactivity testing and holds promise in antibacterial drug discovery. More than 50% of the antibiotics that are currently available on the market are derived from natural products. However, with the easily discoverable antibiotics being found, finding new antibiotics from natural sources has seen limited success. Finding new natural sources for antibacterial activity testing has also proven to be challenging. In addition to exploring new sources of natural products and synthetic biology, omics technology helped to study the biosynthetic machinery of existing natural sources enabling the construction of unnatural synthesizers of bioactive molecules and the identification of molecular targets of antibacterial agents. On the other hand, newer and smarter strategies have been continuously pursued to screen synthetic molecule libraries for new antibiotics and new druggable targets. Biomimetic conditions are explored to mimic the real infection model to better study the ligand-target interaction to enable the designing of more effective antibacterial drugs. This narrative review describes various traditional and contemporaneous approaches of high-throughput screening of natural products and synthetic molecule libraries for antibacterial drug discovery. It further discusses critical factors for HTS assay design, makes a general recommendation, and discusses possible alternatives to traditional HTS of natural products and synthetic molecule libraries for antibacterial drug discovery.

Nephroprotective and nephrotoxic effects of Rhubarb and their molecular mechanisms

Rhubarb, in the form of a traditional Chinese medicine, is used in the treatment of chronic kidney disease (CKD). Previous studies have demonstrated that Rhubarb possesses a good nephroprotective effect, which primarily protects the kidneys from fibrosis, oxidation, inflammation, autophagy, and apoptosis. However, studies have shown that the long-term inappropriate use of Rhubarb may cause damage to renal function. Therefore, how to correctly understand and scientifically evaluate the pharmacodynamics and toxicity of Rhubarb with regard to CKD is a scientific question that urgently needs to be answered. In this review, we explain and illustrate how Rhubarb exerts its nephroprotective effect against CKD. We also describe the mechanisms of action that may cause its nephrotoxicity. Valuable and practical clinical guidance is proposed with regard to methods for mitigating the nephrotoxicity of Rhubarb.

Link of sorafenib resistance with the tumor microenvironment in hepatocellular carcinoma: Mechanistic insights

Sorafenib, a multi-kinase inhibitor with antiangiogenic, antiproliferative, and proapoptotic properties, is the first-line treatment for patients with late-stage hepatocellular carcinoma (HCC). However, the therapeutic effect remains limited due to sorafenib resistance. Only about 30% of HCC patients respond well to the treatment, and the resistance almost inevitably happens within 6 months. Thus, it is critical to elucidate the underlying mechanisms and identify effective approaches to improve the therapeutic outcome. According to recent studies, tumor microenvironment (TME) and immune escape play critical roles in tumor occurrence, metastasis and anti-cancer drug resistance. The relevant mechanisms were focusing on hypoxia, tumor-associated immune-suppressive cells, and immunosuppressive molecules. In this review, we focus on sorafenib resistance and its relationship with liver cancer immune microenvironment, highlighting the importance of breaking sorafenib resistance in HCC.

Inhibitory Effects of Rhein on Renal Interstitial Fibrosis via the SHH-Gli1 Signal Pathway

Background. Rhein is the main extract of Rheum palmatum L., which has been proved to improve the renal function of chronic kidney disease, but its mechanism is not clear. Therefore, this experiment explored the potential pharmacological effect of rhein on renal interstitial fibrosis rats. Methods. This study explores the potential pharmacological action of rhein. In this work, we investigate the potential pharmacological action of rhein in unilateral urethral obstruction (UUO) rats. Thirty Sprague Dawley rats were randomly divided into three groups: sham, UUO, and rhein (rhein-treated UUO rats) groups. The left ureters of the UUO group rats were exposed and bluntly dissected. The rhein group rats were administered an intragastric gavage of rhein (2 mg·kg−1·d−1) for 14 d. Kidney function-related indicators were monitored in these rats, while indexes of pathologic aspects were determined histologically. The expression of α-SMA, TGF-β1, SHH, Gli1, and Snail was quantified using real-time polymerase chain reaction and western blotting. The NRK-49F cells were incubated with and without SHH (100 ng·ml−1) for 48 hours. The SHH-activated NRK-49F cells were incubated with cyclopamine (CNP, 20 umol L−1) or rhein (1 ng·ml−1). The Gli1 and Snail mRNA and protein level were detected. Results. In the in vivo experiment, the results exhibited that UUO caused renal pathological damages. However, these changes could be significantly reversed by the administration of rhein. Compared with the untreated UUO group, the rhein group showed reduced kidney tubular atrophy and necrosis, interstitial fibrosis, hyperplasia, and abnormal deposition of extracellular matrix. Rhein reduced the RNA and protein expression of SHH, Gli1, and Snail of the UUO rats. In the in vitro experiment, CNP or rhein treatment decreased the expression of Gli1 and Snail on mRNA and protein levels in SHH-induced NRK-49F cells, suggesting that CNP or rhein suppresses SHH-induced NRK-49F activation. Taken together, these results demonstrated that rhein suppresses SHH-Gli1-Snail signal pathway activation, with potential implications for the treatment of renal fibrosis. Conclusions. Treatment with rhein remarkably ameliorated renal interstitial fibrosis in UUO rats by regulating the SHH-Gli1-Snail signal pathway.

Investigating the Mechanisms of Jieduquyuziyin Prescription Improves Lupus Nephritis and Fibrosis via FXR in MRL/lpr Mice

Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE) and one of the leading causes of death. An alternative effective treatment to ameliorate and relieve LN and delay the process of renal tissue fibrosis is urgently needed in the clinical setting. Jieduquyuziyin prescription (JP) has been successfully used to treat SLE, but its potential mechanisms are not sufficiently understood. In this study, we treated MRL/lpr mice with JP for 8 weeks and treated human renal tubular epithelial cells (human kidney 2 (HK-2)) with drug-containing serum to observe the antagonistic effects of JP on inflammation and fibrosis, as well as to investigate the possible mechanisms. Results demonstrated that JP significantly reduced urinary protein and significantly improved pathological abnormalities. Metabolomics combined with ingenuity pathway analysis illustrated that the process of kidney injury in lupus mice may be closely related to farnesoid X receptor (FXR) pathway abnormalities. Microarray biomimetic analysis and LN patients indicated that FXR may play a protective role as an effective therapeutic target for LN and renal fibrosis. JP significantly increased the expression of FXR and inhibited the expression of its downstream targets, namely, nuclear transcription factor κB (NF-κB) and α-smooth muscle actin (α-SMA), in the kidney of MRL/lpr mice and HK-2 cells, as confirmed by in vitro and in vivo experiments. In conclusion, JP may mediate the activation of renal FXR expression and inhibit NF-κB and α-SMA expression to exert anti-inflammatory and antifibrotic effects for LN prevention and treatment.

Rhein Inhibits NF-κB Signaling Pathway to Alleviate Inflammatory Response and Oxidative Stress of Rats with Chronic Glomerulonephritis

Objective

To explore the effect and mechanism of rhein on chronic glomerulonephritis (CGN).

Method

Twenty-four eight-week-old male SD rats were randomly divided into following 4 groups (6 rats in each group): control group, CGN group, rhein group, and benazepril (Ben) group. And 5 mg/mL of cationization-bovine serum albumin (C-BSA) was mixed with an equal volume of Freund's incomplete adjuvant for the preparation of 2.5 mg/mL of C-BSA solution. The rat model of CGN was established by injection of C-BSA for six weeks. Calculation of the renal index in rats was conducted. Biochemical detection was performed to measure the level of 24 h urinary protein, blood urea nitrogen (BUN), serum creatinine (SCr), and serum albumin (ALB) of the rats, as well as the level of malondiadehyde (MDA), superoxide (SOD), and glutathione peroxidase (GSH-Px) in the kidney tissue. Hematoxylin and eosin (H&E) staining was utilized to measure histological changes in the kidney of the rats. The level of TNF-α, IL-1β, IL-6, and ICAM-1 in rat kidney tissues was determined by enzyme-linked immunosorbent assay (ELISA). Western blot was applied to check the expression of NF-κB in the nucleus and cytoplasm as well as the expression of IκBα and p-IκBα in rat kidney tissues.

Results

Rhein could decline urinary protein, restore blood biochemical parameters, and protect renal tissue in rats with CGN. Besides, rhein could inhibit the activity of the NF-κB signaling pathway in rats with CGN and could alleviate the inflammatory response and oxidative stress level at the same time.

Conclusion

Rhein alleviates inflammatory responses and oxidative stress in rats with CGN. It also provides a theoretical basis and data support for the therapeutic drugs for CGN.

Shenkang Injection and Its Three Anthraquinones Ameliorates Renal Fibrosis by Simultaneous Targeting IƙB/NF-ƙB and Keap1/Nrf2 Signaling Pathways

Oxidative stress and inflammation are important and critical mediators in the development and progression of chronic kidney disease (CKD) and its complications. Shenkang injection (SKI) has been widely used to treat patients with CKD. Although the anti-oxidative and anti-inflammatory activity was involved in SKI against CKD, its bioactive components and underlying mechanism remain enigmatic. A rat model of adenine-induced chronic renal failure (CRF) is associated with, and largely driven by, oxidative stress and inflammation. Hence, we identified the anti-oxidative and anti-inflammatory components of SKI and further revealed their underlying mechanism in the adenine-induced CRF rats. Compared with control rats, the levels of creatinine, urea, uric acid, total cholesterol, triglyceride, and low-density lipoprotein cholesterol in serum were significantly increased in the adenine-induced CRF rats. However, treatment with SKI and its three anthraquinones including chrysophanol, emodin, and rhein could reverse these aberrant changes. They could significantly inhibit pro-fibrotic protein expressions including collagen I, α-SMA, fibronectin, and vimentin in the kidney tissues of the adenine-induced CRF rats. Of note, SKI and rhein showed the stronger inhibitory effect on these pro-fibrotic protein expressions than chrysophanol and emodin. Furthermore, they could improve dysregulation of IƙB/NF-ƙB and Keap1/Nrf2 signaling pathways. Chrysophanol and emodin showed the stronger inhibitory effect on the NF-κB p65 protein expression than SKI and rhein. Rhein showed the strongest inhibitory effect on p65 downstream target gene products including NAD(P)H oxidase subunits (p47phox, p67phox, and gp91phox) and COX-2, MCP-1, iNOS, and 12-LO in the kidney tissues. However, SKI and rhein showed the stronger inhibitory effect on the significantly downregulated anti-inflammatory and anti-oxidative protein expression nuclear Nrf2 and its target gene products including HO-1, catalase, GCLC, and NQO1 in the Keap1/Nrf2 signaling pathway than chrysophanol and emodin. This study first demonstrated that SKI and its major components protected against renal fibrosis by inhibiting oxidative stress and inflammation via simultaneous targeting IƙB/NF-ƙB and Keap1/Nrf2 signaling pathways, which illuminated the potential molecular mechanism of anti-oxidative and anti-inflammatory effects of SKI.

Rhein regulates redox-mediated Nlrp3 inflammasome activation in intestinal inflammation through macrophage-activated crosstalk

BACKGROUND AND PURPOSE

Macrophage infiltration and activation is a critical step during acute colitis. Redox-mediated Nlrp3 inflammasome activation in macrophages plays a critical role in mediating colonic inflammatory responses. Rhein isolated from the rhizome of rhubarb exhibits anti-inflammatory effects in various diseases. However, its role in regulating acute colonic inflammation is unexplored. This study was designed to investigate the protective mechanisms of rhein during acute gut inflammation and its regulation in macrophage activation.

EXPERIMENTAL APPROACH

The inhibitory effect of rhein on Nlrp3 inflammasome was evaluated in activated macrophages and colitic mice. The expressions of inflammatory mediators, inflammasome complex and redox-related signaling were analyzed by ELISA kits, western blots, immunofluorescence staining and qRT-PCR. Besides, the phenotype of macrophages was also assessed by flow cytometry. Colonic inflammation was evaluated by histological analysis.

KEY RESULTS

Rhein significantly decreased IL-1β secretion via Nlrp3 inflammasome by disturbing its complex assembly in macrophages. Rhein also activated Nrf2-HO1-NQO1 pathway, inhibited Nox2 subunits expression and translocation to regulate redox balance. Moreover, rhein attenuated inflammatory responses by mediating macrophage polarization from M1 to M2 phenotype. NF-κB, AP-1 and MAPK signalings were also involved in improving inflammatory conditions by rhein. In mice with acute intestinal inflammation, rhein treatment attenuated clinical features, reduced macrophage infiltration into the damaged lesions to alleviate colonic inflammation.

CONCLUSION AND IMPLICATIONS

Rhein regulated redox-mediated Nlrp3 inflammasome activation to protect against acute colitis, by interfering with macrophage accumulation and polarization. These findings provide a promising strategy of novel compounds for regulating mucosal inflammation in gastrointestinal disorders.

Combined Untargeted and Targeted Metabolomics Approaches Reveal Urinary Changes of Amino Acids and Energy Metabolism in Canine Babesiosis With Different Levels of Kidney Function

Canine babesiosis is a tick-borne disease with a worldwide distribution, caused by the haemoprotozoan parasites of the genus Babesia. One of the most prevalent complication is acute kidney injury, and an early diagnosis of altered kidney function remains a challenge for veterinary practice. The aim of this study was to assess the urine metabolic profile from dogs with babesiosis and different degree of kidney function using untargeted and targeted MS-based metabolomics approaches. In this study, 22 dogs naturally infected with Babesia canis and 12 healthy dogs were included. Untargeted metabolomics approach identified 601 features with a differential abundance between the healthy group and groups of dogs with babesiosis and different level of kidney function, with 27 of them identified as a match to known standards; while targeted approach identified 17 metabolites with significantly different concentrations between the groups. A pattern of significantly altered metabolites referring to the inflammatory host response, oxidative stress, and energy metabolism modulation in babesiosis was presented. Our findings have demonstrated that kidney dysfunction accompanying canine babesiosis was associated with changes in amino acid metabolism, energy metabolism, fatty acid metabolism, and biochemical pathways such as urea cycle and ammonia detoxication. These findings will enable the inclusion of urinary markers for the detection and monitoring of renal damage in babesiosis, as well as in other similar diseases.