The UCP2-related mitochondrial pathway participates in rhein-induced apoptosis in HK-2 cells

Rhei Radix et Rhizoma and its anthraquinone derivatives: Potential candidates for pancreatitis treatment

BACKGROUND

Pancreatitis is a common exocrine inflammatory disease of the pancreas and lacks specific medication currently. Rhei Radix et Rhizoma (RR) and its anthraquinone derivatives (AQs) have been successively reported for their pharmacological effects and molecular mechanisms in experimental and clinical pancreatitis. However, an overview of the anti-pancreatitis potential of RR and its AQs is limited.

PURPOSE

To summarize and analyze the pharmacological effects of RR and its AQs on pancreatitis and the underlying mechanisms, and discuss their drug-like properties and future perspectives.

METHODS

The articles related to RR and its AQs were collected from the Chinese National Knowledge Infrastructure, Wanfang data, PubMed, and the Web of Science using relevant keywords from the study's inception until April first, 2024. Studies involving RR or its AQs in cell or animal pancreatitis models as well as structure-activity relationship, pharmacokinetics, toxicology, and clinical trials were included.

RESULTS

Most experimental studies are based on severe acute pancreatitis rat models and a few on chronic pancreatitis. Several bioactive anthraquinone derivatives of Rhei Radix et Rhizoma (RRAQs) exert local protective effects on the pancreas by maintaining pancreatic acinar cell homeostasis, inhibiting inflammatory signaling, and anti-fibrosis, and they improve systemic organ function by alleviating intestinal and lung injury. Pharmacokinetic and toxicity studies have revealed the low bioavailability and wide distribution of RRAQs, as well as hepatotoxicity and nephrotoxicity. However, there is insufficient research on the clinical application of RRAQs in pancreatitis. Furthermore, we propose effective strategies for subsequent improvement in terms of balancing effectiveness and safety.

CONCLUSION

RRAQs can be developed as either candidate drugs or novel lead structures for pancreatitis treatment. The comprehensive review of RR and its AQs provides references for optimizing drugs, developing therapies, and conducting future studies on pancreatitis.

Catalpolaglycone disrupts mitochondrial thermogenesis by specifically binding to a conserved lysine residue of UCP2 on the proton leak tunnel

BACKGROUND

Catalpol (CAT), a naturally occurring iridoid glycoside sourced from the root of Rehmannia glutinosa, affects mitochondrial metabolic functions. However, the mechanism of action of CAT against pyrexia and its plausible targets remain to be fully elucidated.

PURPOSE

This study aimed to identify the specific targets of CAT for blocking mitochondrial thermogenesis and to unveil the unique biological mechanism of action of the orthogonal binding mode between the hemiacetal group and lysine residue on the target protein in vivo.

METHODS

Lipopolysaccharide (LPS)/ carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-induced fever models were established to evaluate the potential antipyretic effects of CAT. An alkenyl-modified CAT probe was designed to identify and capture potential targets. Binding capacity was tested using in-gel imaging and a cellular thermal shift assay. The underlying antipyretic mechanisms were explored using biochemical and molecular biological methods. Catalpolaglycone (CA) was coupled with protein profile identification and molecular docking analysis to evaluate and identify its binding mode to UCP2.

RESULTS

After deglycation of CAT in vivo, the hemiacetal group in CA covalently binds to Lys239 of UCP2 in the mitochondria of the liver via an ɛ-amine nucleophilic addition. This irreversible binding affects proton leakage and improves mitochondrial membrane potential and ADP/ATP transformation efficiency, leading to an antipyretic effect.

CONCLUSION

Our findings highlight the potential role of CA in modulating UCP2 activity or function within the mitochondria and open new avenues for investigating the therapeutic effects of CA on mitochondrial homeostasis.

Potential Medicinal Value of Rhein for Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the primary cause of mortality among diabetic patients. With the increasing prevalence of diabetes, it has become a major concern around the world. The therapeutic effect of clinical use of drugs is far from expected, and therapy choices to slow the progression of DKD remain restricted. Therefore, research on new drugs and treatments for DKD has been a hot topic in the medical field. It has been found that rhein has the potential to target the pathogenesis of DKD and has a wide range of pharmacological effects on DKD, such as anti-nephritis, decreasing blood glucose, controlling blood lipids and renal protection. In recent years, the medical value of rhein in the treatment of diabetes, DKD and renal disease has gradually attracted worldwide attention, especially its potential in the treatment of DKD. Currently, DKD can only be treated with medications from a single symptom and are accompanied by adverse effects, while rhein improves DKD with a multi-pathway and multi-target approach. Therefore, this paper reviews the therapeutic effects of rhein on DKD, and proposes solutions to the limitations of rhein itself, in order to provide valuable references for the clinical application of rhein in DKD and the development of new drugs.

Tetramethylpyrazine-Rhein Derivative inhibits the migration of canine inflammatory mammary carcinoma cells by mitochondrial damage-mediated apoptosis and cadherins downregulation

BACKGROUND

Canine inflammatory mammary carcinoma (CIMC) has a high incidence of metastasis, high lethality, and poor prognosis, which needs novel adjuvant agents. Tetramethylpyrazine-Rhein Derivative (TRD) has been shown to have antitumor activity, which is a potential research direction for CIMC.

PURPOSE

This study evaluated the efficacy of TRD on CIMC in vitro and in vivo, and provided possibilities for the application of active compounds in traditional Chinese medicine.

METHODS

In vitro, TRD cytotoxicity was measured with CCK-8. Flow cytometry and transmission electron microscope were used to detect the cell cycle, cell death, and changes in mitochondria. Wound-healing assay, cell invasion assay, and scanning electron microscope were used to evaluate the suppression of cell migration and invasion. Expression changes were detected by RT-qPCR and western blot assay. In vivo, the lung metastasis models were randomly divided into control, low-dose TRD, high-dose TRD, and positive groups. Each group was administered orally once a day for 18 days and took in vivo imaging photos.

RESULTS

The IC₅₀ of TRD in CHMp and MDCK were 42.59 and 79.37 μM, respectively. TRD mediated cell apoptosis by mitochondrial damage and caused S and G₂/M phase arrest by downregulating cyclin B1. Moreover, TRD reduced filopodia and inhibited cell migration by downregulating cadherins. In CIMC lung metastasis models, TRD could effectively inhibit tumor growth (P < 0.001) in the lungs without significant toxicity.

CONCLUSION

TRD showed potential activity to inhibit CIMC lung metastasis with multi-target and low toxicity.

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.

Rhein for treating diabetes mellitus: A pharmacological and mechanistic overview

With the extension of life expectancy and changes in lifestyle, the prevalence of diabetes mellitus is increasing worldwide. Rheum palmatum L. a natural botanical medicine, has been used for thousands of years to prevent and treat diabetes mellitus in Eastern countries. Rhein, the main active component of rhubarb, is a 1, 8-dihydroxy anthraquinone derivative. Previous studies have extensively explored the clinical application of rhein. However, a comprehensive review of the antidiabetic effects of rhein has not been conducted. This review summarizes studies published over the past decade on the antidiabetic effects of rhein, covering the biological characteristics of Rheum palmatum L. and the pharmacological effects and pharmacokinetic characteristics of rhein. The review demonstrates that rhein can prevent and treat diabetes mellitus by ameliorating insulin resistance, possess anti-inflammatory and anti-oxidative stress properties, and protect islet cells, thus providing a theoretical basis for the application of rhein as an antidiabetic agent.

Research Progress on the Positive and Negative Regulatory Effects of Rhein on the Kidney: A Review of Its Molecular Targets

Currently, both acute kidney injury (AKI) and chronic kidney disease (CKD) are considered to be the leading public health problems with gradually increasing incidence rates around the world. Rhein is a monomeric component of anthraquinone isolated from rhubarb, a traditional Chinese medicine. It has anti-inflammation, anti-oxidation, anti-apoptosis, anti-bacterial and other pharmacological activities, as well as a renal protective effects. Rhein exerts its nephroprotective effects mainly through decreasing hypoglycemic and hypolipidemic, playing anti-inflammatory, antioxidant and anti-fibrotic effects and regulating drug-transporters. However, the latest studies show that rhein also has potential kidney toxicity in case of large dosages and long use times. The present review highlights rhein's molecular targets and its different effects on the kidney based on the available literature and clarifies that rhein regulates the function of the kidney in a positive and negative way. It will be helpful to conduct further studies on how to make full use of rhein in the kidney and to avoid kidney damage so as to make it an effective kidney protection drug.

Nephrotoxicity induced by natural compounds from herbal medicines - a challenge for clinical application

Herbal medicines (HMs) have long been considered safe and effective without serious toxic and side effects. With the continuous use of HMs, more and more attention has been paid to adverse reactions and toxic events, especially the nephrotoxicity caused by natural compounds in HMs. The composition of HMs is complex and various, especially the mechanism of toxic components has been a difficult and hot topic. This review comprehensively summarizes the kidney toxicity characterization and mechanism of nephrotoxic natural compounds (organic acids, alkaloids, glycosides, terpenoids, phenylpropanoids, flavonoids, anthraquinones, cytotoxic proteins, and minerals) from different sources. Recommendations for the prevention and treatment of HMs-induced kidney injury were provided. In vitro and in vivo models for evaluating nephrotoxicity and the latest biomarkers are also included in this investigation. More broadly, this review may provide theoretical basis for safety evaluation and further comprehensive development and utilization of HMs in the future.

Protective Effects of Mitochondrial Uncoupling Protein 2 against Aristolochic Acid I-Induced Toxicity in HK-2 Cells

Aristolochic acid I (AA I) is one of the most abundant and toxic aristolochic acids that is reported to cause Aristolochic acid nephropathy (AAN). This paper was designed to assess whether mitochondrial Uncoupling Protein 2 (UCP2), which plays an antioxidative and antiapoptotic role, could protect human renal proximal tubular epithelial (HK-2) cells from toxicity induced by AA I. In this study, HK-2 cells were treated with different concentrations of AA I with or without UCP2 inhibitor (genipin). To upregulate the expression of UCP2 in HK-2 cells, UCP2-DNA transfection was performed. The cell viability was evaluated by colorimetric method using MTT. A series of related biological events such as Reactive Oxygen Species (ROS), Glutathione peroxidase (GSH-Px), and Malondialdehyde (MDA) were evaluated. The results showed that the cytotoxicity of AA I with genipin group was much higher than that of AA I alone. Genipin dramatically boosted oxidative stress and exacerbated AA I-induced apoptosis. Furthermore, the increased expression of UCP2 can reduce the toxicity of AA I on HK-2 cells and upregulation of UCP2 expression can reduce AA I-induced oxidative stress and apoptosis. In conclusion, UCP2 might be a potential target for alleviating AA I-induced nephrotoxicity.

Anti-cancer effect of astrakurkurol from a folklore tribal mushroom on human hepatocellular carcinoma cells via mediating cell cycle inhibition, apoptosis, and migration

Astraeus hygrometricus extensively been utilized by tribal people for long time. A triterpene, astrakurkurol has been isolated from A. hygrometricus but anticancer effect of this novel triterpene has imperceptibly been investigated. Motive of this research was to scrutinize its underlying apoptotic mechanism in HepG2 cells. Cytotoxicity studies demonstrated a selective effect of astrakurkurol with towering influence in HepG2 than Thle2 cells. The exposure of these triterpene-induced marked apoptotic morphological changes enhanced the rate of cell apoptosis and arrest cell cycle at G0/G1. Furthermore, these results are aided by decline in the expression of Bcl-2, Bcl-xL with an increase in the expression of p53, Bax, Fas, FADD together with the activation of caspase cascade. Astrakurkurol also displayed a remarkable anti-migratory capacity at a lower concentration. Altogether, studies explained anti-proliferative, pro-apoptotic, and anti-migratory efficacy of astrakurkurol on HepG2, composing a gripping challenge in the advancement of novel treatments against hepatocellular carcinoma. PRACTICAL APPLICATIONS: Mushrooms, the minuscule pharmaceutical factory, bear hundreds of novel elements with incredible biological attributes. Triterpenoids from mushrooms has been proven to bear potentials of curing cancer. This study highlights the cytotoxic and anti-migratory effects of novel triterpene in vitro in HepG2 cell, an HCC cell line. Astrakurkurol mediated cell death via both extrinsic and intrinsic apoptotic signaling. Utilization of astrakurkurol will provide a non-toxic substitute of chemotherapy and also uplift the value of forsaken taxon, Astraeus and boost the rural acceptance.

Predicting the potential toxicity of 26 components in Cassiae semen using in silico and in vitro approaches

•

A combination of in silico and in vitro methods was applied.

•

The potential toxicity of 26 components isolated from Cassiae semen is predicted.

•

Six compounds were predicted toxic to liver & ten compounds toxic to kidney.

•

Special anthraquinones and anthraquinone-glucosides are potential toxicants.

•

Specific group of anthraquinones influences hepatic or renal cytotoxicity.

Cassiae semen are dried and ripe seeds of Cassia obtusifolia L. or Cassia tora L. (Fabaceae) and have been made into roasted tea or used as a traditional medicine in Asian countries. However, it was reported to result in liver and renal toxicity. The components of Cassiae semen that induce hepatotoxicity or nephrotoxicity remain unknown. In the present study, we evaluate the potential toxicity of 26 newly isolated compounds from Cassiae semen using quantitative structure–activity relationship (QSAR) methods and co-culture of hepatic and renal cell approaches, and we aim to illustrate the relationship between the structural characteristics and cytotoxicity by general linear models (GLMs). Both the QSAR models and co-culture of hepatic and renal cell systems predicted that 6 compounds were potentially hepatotoxic, 10 compounds were potentially nephrotoxic, and specific anthraquinones and anthraquinone-glucosides were potential toxicants in Cassiae semen. Specific groups such as –OH and –OCH₃ at the R1, R2, R3, and R7 positions influenced the cytotoxicity.

Therapeutic Emergence of Rhein as a Potential Anticancer Drug: A Review of Its Molecular Targets and Anticancer Properties

According to the World Health Organization (WHO), cancer is the second-highest cause of mortality in the world, and it kills nearly 9.6 million people annually. Besides the fatality of the disease, poor prognosis, cost of conventional therapies, and associated side-effects add more burden to patients, post-diagnosis. Therefore, the search for alternatives for the treatment of cancer that are safe, multi-targeted, effective, and cost-effective has compelled us to go back to ancient systems of medicine. Natural herbs and plant formulations are laden with a variety of phytochemicals. One such compound is rhein, which is an anthraquinone derived from the roots of Rheum spp. and Polygonum multiflorum. In ethnomedicine, these plants are used for the treatment of inflammation, osteoarthritis, diabetes, and bacterial and helminthic infections. Increasing evidence suggests that this compound can suppress breast cancer, cervical cancer, colon cancer, lung cancer, ovarian cancer, etc. in both in vitro and in vivo settings. Recent studies have reported that this compound modulates different signaling cascades in cancer cells and can prevent angiogenesis and progression of different types of cancers. The present review highlights the cancer-preventing and therapeutic properties of rhein based on the available literature, which will help to extend further research to establish the chemoprotective and therapeutic roles of rhein compared to other conventional drugs. Future pharmacokinetic and toxicological studies could support this compound as an effective anticancer agent.

Protein profiling of SH-SY5Y neuroblastoma cells: The effect of rhein

4,5-Dihydroxyanthraquinone-2-carboxylic acid (Rhein) has been shown to have various physiological and pharmacological properties including anticancer activity and modulatory effects on bioenergetics. In this study, we explored the impact of rhein on protein profiling of undifferentiated (UC) and differentiated (DC) SH-SY5Y cells. Besides that, the cellular morphology and expression of differentiation markers were investigated to determine the effect of rhein on retinoic acidinduced neuronal cell differentiation. Using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ ionization-time-of-flight mass spectrometry we evaluated the changes in the proteome of both UC and DC SH-SY5Y cells after 24 h treatment with rhein. Validation of selected differentially expressed proteins and the assessment of neuronal differentiation markers were performed by western blotting. Proteomic analysis revealed significant changes in the abundance of 15 proteins linked to specific cellular processes such as cytoskeleton structure and regulation, mitochondrial function, energy metabolism, protein synthesis and neuronal plasticity. We also observed that the addition of rhein to the cultured cells during differentiation resulted in a significantly reduced neurite outgrowth and decreased expression of neuronal markers. These results indicate that rhein may strongly interfere with the differentiation process of SH-SY5Y neuroblastoma cells and is capable of inducing marked proteomic changes in these cells.

Analysis of transcriptional response in zebrafish eleutheroembryos exposed to climbazole: Signaling pathways and potential biomarkers

Climbazole is an antifungal active ingredient used in personal care products. After application this chemical reaches the aquatic environment and may pose a risk to fish. In the present study, we measured the transcriptional effects of essential genes related to a wide range of signaling pathways on zebrafish eleutheroembryos exposed to climbazole at environmentally relevant and predicted worst-case environmental concentrations, and explored the potential biomarkers via partial least squares discriminant analysis. Transcription analysis covering up to 73 genes revealed significant down-regulation of circadian rhythm- and steroidogenesis-related genes in zebrafish embryos and larvae after exposure to environmentally relevant concentrations of climbazole. This topical antifungal agent also modulated the transcripts of genes involved in inflammation, oxidative stress, oocyte maturation, and sexual differentiation at predicted worst-case environmental concentrations. In addition, mprα, igf3, nr1d1, nr1d2b, cyp19a1a, vtg1, il-1β, and il-8 were chosen as potential biomarkers in embryonic zebrafish following exposure to climbazole. These findings can help us understand the remarkable transcriptional response to climbazole in the early life stage of zebrafish. Future research should elucidate whether the transcriptional modulation translates into metabolic phenotypes associated with the corresponding signaling pathways. Environ Toxicol Chem 2019;38:794-805. © 2019 SETAC.