Immunosuppressive activity of daphnetin, one of coumarin derivatives, is mediated through suppression of NF-κB and NFAT signaling pathways in mouse T cells

Identification and Functional Analysis of Novel Long Intergenic RNA in Chicken Macrophages Infected with Avian Pathogenic Escherichia coli

Avian pathogenic E. coli (APEC), a widespread bacterium, results in serious economic losses to the poultry industry annually, and it poses a threat to human health due to the contaminated retail poultry meat and eggs. Recently, it has been demonstrated that long non-coding RNAs played important roles in regulating gene expression and the animal immune response. This study aimed to systematically explore the function of the novel long intergenic non-coding transcript, lincRNA-73240, upon APEC infection. A bioinformatics analysis indicated that lincRNA-73240 had no coding ability and a relative stable secondary structure with multiple hairpin rings. Moreover, the RT-qPCR results showed that lincRNA-73240 was highly expressed in lungs, heart, liver, spleen, cecum tonsils, thymus, ileum, bursa of Fabricius, harderian gland, and muscles in comparison to the cerebrum. Additionally, overexpression of lincRNA-73240 can promote the expression levels of inflammation, apoptosis, autophagy, and oxidative stress-related genes, as well as the production of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) upon APEC infection, which lead to cellular injury and apoptosis. These findings collectively establish a foundation for the study of the biological function of chicken lincRNA-73240 and provide a theoretical basis for further research on the molecular mechanisms of the chicken immune response.

The molecular effects underlying the pharmacological activities of daphnetin

As an increasingly well-known derivative of coumarin, daphnetin (7,8-dithydroxycoumarin) has demonstrated various pharmacological activities, including anti-inflammation, anti-cancer, anti-autoimmune diseases, antibacterial, organ protection, and neuroprotection properties. Various studies have been conducted to explore the action mechanisms and synthetic methods of daphnetin, given its therapeutic potential in clinical. Despite these initial insights, the precise mechanisms underlying the pharmacological activities of daphnetin remain largely unknown. In order to address this knowledge gap, we explore the molecular effects from the perspectives of signaling pathways, NOD-like receptor protein 3 (NLRP3) inflammasome and inflammatory factors; and try to find out how these mechanisms can be utilized to inform new combined therapeutic strategies.

Antiplatelet Effect of Daphnetin Is Regulated by cPLA2-Mediated Thromboxane A2 Generation in Mice

Coumarin derivatives have been recognized for their antithrombotic, anti-inflammatory, and antioxidant properties, and daphnetin is one of the natural coumarin derivatives isolated from Daphne Koreana Nakai. Although the pharmacological value of daphnetin is well documented in diverse biological activities, its antithrombotic effect has not been studied to date. Here, we characterized the role and underlying mechanism of daphnetin in the regulation of platelet activation using murine platelets. In order to check the effect of daphnetin on platelet function, we first measured the effect of daphnetin on platelet aggregation and secretion. Collagen-induced platelet aggregation and dense granule secretion were partially inhibited by daphnetin. Interestingly, 2-MeSADP-induced secondary waves of aggregation and secretion were completely inhibited by daphnetin. It is known that 2-MeSADP-induced secretion and the resultant secondary wave of aggregation are mediated by the positive feedback effect of thromboxane A₂ (TxA₂) generation, suggesting the important role of daphnetin on TxA₂ generation in platelets. Consistently, daphnetin did not affect the 2-MeSADP-induced platelet aggregation in aspirinated platelets where the contribution of TxA₂ generation was blocked. Additionally, platelet aggregation and secretion induced by a low concentration of thrombin, which is affected by the positive feedback effect of TxA₂ generation, were partially inhibited in the presence of daphnetin. Importantly, 2-MeSADP- and thrombin-induced TxA₂ generation was significantly inhibited in the presence of daphnetin, confirming the role of daphnetin on TxA₂ generation. Finally, daphnetin significantly inhibited 2-MeSADP-induced cytosolic phospholipase A₂ (cPLA₂) and ERK phosphorylation in non-aspirinated platelets. Only cPLA₂ phosphorylation, not ERK phosphorylation, was significantly inhibited by daphnetin in aspirinated platelets. In conclusion, daphnetin plays a critical role in platelet function by inhibiting TxA₂ generation through the regulation of cPLA₂ phosphorylation.

Phytochemicals as Immunomodulatory Agents in Melanoma

Cutaneous melanoma is an immunogenic highly heterogenic tumor characterized by poor outcomes when it is diagnosed late. Therefore, immunotherapy in combination with other anti-proliferative approaches is among the most effective weapons to control its growth and metastatic dissemination. Recently, a large amount of published reports indicate the interest of researchers and clinicians about plant secondary metabolites as potentially useful therapeutic tools due to their lower presence of side effects coupled with their high potency and efficacy. Published evidence was reported in most cases through in vitro studies but also, with a growing body of evidence, through in vivo investigations. Our aim was, therefore, to review the published studies focused on the most interesting phytochemicals whose immunomodulatory activities and/or mechanisms of actions were demonstrated and applied to melanoma models.

Daphnetin, a Coumarin in Genus Stellera Chamaejasme Linn: Chemistry, Bioactivity and Therapeutic Potential

Coumarins is a huge family of phenolic compounds containing a common structure of 2 H -1-benzopyran-2-one. Nowadays, more than 1,300 natural-based coumarins have been identified in a variety of plants, bacteria and fungi, many of them exhibited promising biomedical performance. Daphnetin (7,8-dihydroxycoumarin) is a typical coumarin associated with a couple of bioactivities such as anti-cancer, antibacterial, anti-inflammatory and anti-arthritis. In the treatment of diseases, it has been verified that daphnetin has outstanding therapeutic effects on diabetes, arthritis, transplant rejection, cancer and even on central nervous system diseases. Herein, we summarized the chemical synthetic methodologies, bioactivities, therapeutic potentials and structure-activity relationships of daphnetin and its derivatives. Hopefully, this review would be beneficial for the discovery of new coumarin-based biomedicine in the near future.

Metabolic Profiling, Chemical Composition, Antioxidant Capacity, and In Vivo Hepato- and Nephroprotective Effects of Sonchus cornutus in Mice Exposed to Cisplatin

Sonchus cornutus (Asteraceae) is a wild. edible plant that represents a plentiful source of polyphenolic compounds. For the first time, the metabolic analysis profiling demonstrated the presence of anthocyanidin glycosides, coumarins, flavonoids and their corresponding glycosides, and phenolic acids. The total phenolic compounds were determined to be 206.28 ± 14.64 mg gallic acid equivalent/gm, while flavonoids were determined to be 45.56 ± 1.78 mg quercetin equivalent/gm. The crude extract of S. cornutus exhibited a significant 1,1-diphenyl-2-picrylhydrazyl free radical scavenging effect with half-maximal inhibitory concentration (IC50) of 16.10 ± 2.14 µg/mL compared to ascorbic acid as a standard (10.64 ± 0.82 µg/mL). In vitro total antioxidant capacity and ferric reducing power capacity assays revealed a promising reducing potential of S. cornutus extract. Therefore, the possible protective effects of S. cornutus against hepatic and renal toxicity induced by cisplatin in experimental mice were investigated. S. cornutus significantly ameliorated the cisplatin-induced disturbances in liver and kidney functions and oxidative stress, decreased MDA, ROS, and NO levels, and restored CAT and SOD activities. Besides, it reversed cisplatin-driven upregulation in inflammatory markers, including iNOS, IL-6, and IL-1β levels and NF-κB and TNF-α expression, and elevated anti-inflammatory IL-10 levels and Nrf2 expression. Additionally, the extract mitigated cisplatin alteration in apoptotic (Bax and caspase-3) and anti-apoptotic (Bcl-2) proteins. Interestingly, hepatic, and renal histopathology revealed the protective impacts of S. cornutus against cisplatin-induced pathological changes. Our findings guarantee a protective effect of S. cornutus against cisplatin-induced hepatic and renal damage via modulating oxidative stress, inflammation, and apoptotic pathways.

Transcriptional Regulation of RIP2 Gene by NFIB Is Associated with Cellular Immune and Inflammatory Response to APEC Infection

Avian pathogenic E. coli (APEC) can cause localized or systemic infection, resulting in large economic losses per year, and impact health of humans. Previous studies showed that RIP2 (receptor interacting serine/threonine kinase 2) and its signaling pathway played an important role in immune response against APEC infection. In this study, chicken HD11 cells were used as an in vitro model to investigate the function of chicken RIP2 and the transcription factor binding to the RIP2 core promoter region via gene overexpression, RNA interference, RT-qPCR, Western blotting, dual luciferase reporter assay, CHIP-PCR, CCK-8, and flow cytometry assay following APEC stimulation. Results showed that APEC stimulation promoted RIP2 expression and cells apoptosis, and inhibited cells viability. Knockdown of RIP2 significantly improved cell viability and suppressed the apoptosis of APEC-stimulated cells. Transcription factor NFIB (Nuclear factor I B) and GATA1 (globin transcription factor 1) binding site was identified in the core promoter region of RIP2 from −2300 bp to −1839 bp. However, only NFIB was confirmed to be bound to the core promoter of RIP2. Overexpression of NFIB exacerbated cell injuries with significant reduction in cell viability and increased cell apoptosis and inflammatory cytokines levels, whereas opposite results were observed in NFIB inhibition treatment group. Moreover, RIP2 was up-regulated by NFIB overexpression, and RIP2 silence mitigated the effect of NFIB overexpression in cell apoptosis, inflammation, and activation of NFκB signaling pathways. This study demonstrated that NFIB overexpression accelerated APEC-induced apoptosis and inflammation via up-regulation of RIP2 mediated downstream pathways in chicken HD11 cells.

Daphnetin inhibits the survival of hepatocellular carcinoma cells through regulating Wnt/β-catenin signaling pathway

Evidence has demonstrated that Daphnetin has antiangiogenesis activity, indicating it might be a new multi-targeted medication for cancer therapy. Here, we aimed to reveal Daphnetin role in hepatocellular carcinoma (HCC) progression and the underlying mechanism. Huh7 and SK-HEP-1, two human HCC cell lines were used in this study. MTT （3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide）, colony formation, flow cytometry, and tumor-bearing experiments were applied to evaluate the effects of different concentrations of Daphnetin on cell viability, apoptosis, cell cycle, and in vivo tumor formation, respectively. Real-time PCR （Polymerase Chain Reaction）and western blotting were applied to measure the mRNA and protein levels of β-catenin. We observed that Daphnetin inhibited cell viability and tumorigenesis, promoted cell apoptosis, and induced a G1 phase arrest in a dose-dependent manner in both Huh7 and SK-HEP-1 cells, which were rescued by SKL2001, an activator of the Wnt/β-catenin signaling. Taken together, this study reveals that Daphnetin exerts an antitumor role in HCC through the inactivation of Wnt/β-catenin signaling.

Vomifoliol isolated from mangrove plant Ceriops tagal inhibits the NFAT signaling pathway with CN as the target enzyme in vitro

Vomifoliol, a natural sesquiterpene compound, is a secondary metabolite isolated from the mangrove plant Ceriops tagal. The present study aimed to determine the immunosuppressive effects and underlying mechanisms of vomifoliol on Jurkat cells in vitro. The results show that vomifoliol significantly inhibited calcineurin (CN) at concentrations resulting in relatively low cytotoxicity. Moreover, vomifoliol was found to exert an inhibitory effect on phorbol 12-myristate 13-acetate (PMA)/ ionomycin (Io) -induced Jurkat cells and the dephosphorylation of NFAT1. In addition, it reduced the expression of IL-2. Based on these results, we concluded that vomifoliol may inhibit the immune response of Jurkat cells, and vomifoliol may use CN as the target enzyme to inhibit NFAT signaling pathway. Therefore, vomifoliol may be promising as a low-toxic natural immunosuppressant.

Mechanistic interplay of various mediators involved in mediating the neuroprotective effect of daphnetin

Daphnetin is a 7, 8 dihydroxy coumarin isolated from different medicinal plants of the Thymelaeaceae family and exhibits copious pharmacological activities including neuroprotection, anti-cancer, anti-malarial, anti-inflammatory, anti-parasitic and anti-arthritic activity. It has been proved to be an effective neuroprotective agent in several preclinical animal studies and cell line examinations. It is found to interact with different cellular mediators and signaling pathways to confer protection against neurodegeneration. The reactive oxygen species and inflammatory mediators are the major culprits of different neurodegenerative diseases. Oxidative stress activates the pro-apoptotic proteins and inhibits anti-apoptotic proteins, leading to neuronal cell death. Daphnetin restores cellular redox balance by upregulating the antioxidants level (GSH and SOD), anti-apoptotic protein (Bcl-2), as well as by reducing the levels of proinflammatory cytokines, executioner caspase-3, pro-apoptotic-Bax, and oxidative stress markers. Furthermore, activation of Nrf-2/HO-1 signaling and upregulation of HSP-70 governs the protection elicited by daphnetin against oxidative stress-induced neuronal apoptosis. Daphnetin modulated inhibition of JNK-MAPK, JAK-STAT, and TLR-4/NF-κB signaling pathways also contributed to its neuroprotective effect. The positive effects of daphnetin have been also related to its AChE, BChE, and BACE-1 inhibitory potential. The present review has been designed to explore the mechanistic interplay of various mediators in mediating the neuroprotective effects of daphnetin.

Daphnetin exerts an anticancer effect by attenuating the pro-inflammatory cytokines

Leukemia is a malignant tissue-forming disease, which induces the overproduction of large numbers of immature blood cells entering the peripheral blood. It is well documented that inflammation plays a crucial role in the expansion of leukemia. Daphnetin has confirmed anti-inflammatory effects against various diseases. In this experimental study, we evaluated the anti-leukemia and anti-inflammatory effect of daphnetin against benzene-induced leukemia in rats and explored the underlying mechanism. Benzene was used for inducing leukemia in experimental rats. The rats were divided into different groups and the body weight, hematological parameters, bone marrow cells, cytokines, and inflammatory mediators were estimated. Reverse transcription polymerase chain reaction (RT-PCR) was used for estimating the messenger RNA (mRNA) expression of sphingosine-1-phosphate receptor-1. Daphnetin-treated rats showed upregulation of body weight compared to other groups. Moreover, Daphnetin reduced blasts in leukemic rats. It also altered hematological parameters such as red blood cells, white blood cells, lymphocytes, neutrophils, monocytes, eosinophils, monocytes, and basophils, respectively. Daphnetin-treated rats showed a reduction of pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-2, IL-6, and inflammatory mediators including nuclear factor-κB. RT-PCR showed upregulated mRNA expression of sphingosine-1-phosphate receptor-1 of daphnetin-treated group rats compared to other groups. The current study showed that the anti-inflammatory effect of daphnetin against the benzene-induced leukemia via alteration of cytokines.

Daphnetin, a natural coumarin averts reserpine-induced fibromyalgia in mice: modulation of MAO-A

Fibromyalgia is a common, chronic, and generalized pain syndrome that is often associated with comorbid depression. The etiology of fibromyalgia is complex; most researchers have documented that the hallmark symptoms are due to the central nervous system's abnormal functioning. Neurotransmitters such as serotonin, norepinephrine, and glutamate, have been reported to be key regulators of fibromyalgia syndrome. Daphnetin is a 7, 8 dihydroxy coumarin widely distributed in Thymelaeaceae family plants, possessing various activities such as anti-arthritic, anti-tumor, anti-malarial, and anti-parasitic. The present study was designed to explore the potential of daphnetin against reserpine-induced fibromyalgia in mice. In mice, a fibromyalgia-like state was achieved by injecting reserpine (0.5 mg/kg, s.c) continuously for 3 days. All behavioral tests were conducted on the 4th and 6th day of experimentation. Reserpine administration significantly increased the mechanical hypersensitivity in electronic von Frey (eVF) and pressure application measurement (PAM) tests. It also increased the immobility period and time to reach the platform in force swim test (FST) and Morris water maze (MWM) test, respectively. In the biochemical analysis, reserpine treatment upregulated the monoamine oxidase-A (MAO-A) activity and level of glutamate, tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and thiobarbituric acid reactive substances (TBARS). Whereas, it decreased the level of glutathione (GSH), dopamine, serotonin, and norepinephrine. Daphnetin pretreatment attenuated the behavioral and biochemical changes induced by reserpine. Thus, the current investigation results delineate that daphnetin might exert its protective effect by inhibiting inflammatory stress and MAO-A-mediated neurotransmitter depletion and oxidative stress.

Immunosuppressive activity of daphnetin on the humoral immune responses in ovalbumin-sensitized BALB/c mice

INTRODUCTION

Most of the immunosuppressive drugs are used for the treatment of autoimmune disease, allergic diseases, and transplant rejection, but toxicity is the major obstacle for the potent drugs in the wide use of these immunosuppressive drugs. Daphnetin, a Chinese herbal product, has been reported that daphnetin possesses antimicrobial, anticoagulation, antimalarial, anticancer, and antioxidant activity. In a previous study, we found that daphnetin exhibited a potential immunosuppressive effect on LPS-induced B lymphocyte cells in vitro, therefore, in this research, we investigated the immunosuppressive effects of daphnetin in BALB/c mice use OVA as a prototype antigen.

METHODS

Sixty BALB/c mice were divided into six groups. The emulsion (100 μL containing 100 μg OVA) was injected subcutaneously with OVA + CFA into the shaved backs of the BALB/c mice on day 1, and a boosting injection was administered in OVA + IFA 2 weeks later. Beginning on the day of immunization, the immunized mice were administered intraperitoneally with daphnetin at a dose of 5, 10, and 20 mg/kg in saline solution for 28 consecutive days. We measured the effect of daphnetin on OVA-specific antibody, cytokine production, and Splenocyte proliferation in vivo.

RESULTS

The results revealed that daphnetin significantly suppressed serum immunoglobulin G levels (IgG), and the OVA-specific IgG subclasses IgG1 and IgG2b, daphnetin was also significantly decreased the Th1 and Th2 cytokine productions, inhibited the splenocytes proliferation rate in vivo.

CONCLUSIONS

It proved that daphnetin could suppress humoral response activity on OVA-sensitized mice, suggesting a potential role on daphnetin as a new immunosuppressive drug.

Elucidating Antibacterial Activity and Mechanism of Daphnetin against Pseudomonas fluorescens and Shewanella putrefaciens

In this research, the antibacterial activity and mechanism of daphnetin against Pseudomonas fluorescens and Shewanella putrefaciens were evaluated. The minimum inhibitory concentration (MIC) of daphnetin on P. fluorescens and S. putrefaciens was 0.16 and 0.08 mg·mL−1, respectively. The growth curve test also showed that daphnetin had a good antibacterial effect. The results of intracellular component leakage and cell viability analysis illustrated that daphnetin destroyed the morphology of the cell membrane. According to scanning electron microscope and transmission electron microscope observations, the treated bacterial cells displayed obvious morphological and ultrastructural changes in the cell membrane of the two tested strains, whichconfirmed daphnetin’s damage to the integrity of the cell membrane. The findings indicated that daphnetin mainly exerted its antibacterial effect by destroying the membrane and suggested that it had good potential to be as a natural food preservative.

Daphnetin inhibits proliferation and inflammatory response in human HaCaT keratinocytes and ameliorates imiquimod-induced psoriasis-like skin lesion in mice

BACKGROUND

Psoriasis is a common chronic inflammatory skin disease. Keratinocytes hyperproliferation and excessive inflammatory response contribute to psoriasis pathogenesis. The agents able to attenuate keratinocytes hyperproliferation and excessive inflammatory response are considered to be potentially useful for psoriasis treatment. Daphnetin exhibits broad bioactivities including anti-proliferation and anti-inflammatory. This study aims to evaluate the anti-psoriatic potential of daphnetin in vitro and in vivo, and explore underlying mechanisms.

METHODS

HaCaT keratinocytes was stimulated with the mixture of IL-17A, IL-22, oncostatin M, IL-1α, and TNF-α (M5) to establish psoriatic keratinocyte model in vitro. Cell viability was measured using Cell Counting Kit-8 (CCK-8). Quantitative Real-Time PCR (qRT-PCR) was performed to measure the mRNA levels of hyperproliferative marker gene keratin 6 (KRT6), differentiation marker gene keratin 1 (KRT1) and inflammatory factors IL-1β, IL-6, IL-8, TNF-α, IL-23A and MCP-1. Western blotting was used to detect the protein levels of p65 and p-p65. Indirect immunofluorescence assay (IFA) was carried out to detect p65 nuclear translocation. Imiquimod (IMQ) was used to construct psoriasis-like mouse model. Psoriasis severity (erythema, scaling) was scored based on Psoriasis Area Severity Index (PASI). Hematoxylin and eosin (H&E) staining was performed to examine histological change in skin lesion. The expression of inflammatory factors including IL-6, TNF-α, IL-23A and IL-17A in skin lesion was measured by qRT-PCR.

RESULTS

Daphnetin attenuated M5-induced hyperproliferation in HaCaT keratinocytes. M5 stimulation significantly upregulated mRNA levels of IL-1β, IL-6, IL-8, TNF-α, IL-23A and MCP-1. However, daphnetin treatment partially attenuated the upregulation of those inflammatory cytokines. Daphnetin was found to be able to inhibit p65 phosphorylation and nuclear translocation in HaCaT keratinocytes. In addition, daphnetin significantly ameliorate the severity of skin lesion (erythema, scaling and epidermal thickness, inflammatory cell infiltration) in IMQ-induced psoriasis-like mouse model. Daphnetin treatment attenuated IMQ-induced upregulation of inflammatory cytokines including IL-6, IL-23A and IL-17A in skin lesion of mice.

CONCLUSIONS

Daphnetin was able to attenuate proliferation and inflammatory response induced by M5 in HaCaT keratinocytes through suppression of NF-κB signaling pathway. Daphnetin could ameliorate the severity of skin lesion and improve inflammation status in IMQ-induced psoriasis-like mouse model. Daphnetin could be an attractive candidate for future development as an anti-psoriatic agent.

Daphnetin suppresses experimental abdominal aortic aneurysms in mice via inhibition of aortic mural inflammation

Rupture of abdominal aortic aneurysm (AAA) is a devastating event that can be prevented by inhibiting the growth of small aneurysms. Therapeutic strategies targeting certain events that promote the development of AAA must be developed, in order to alter the course of AAA. Chronic inflammation of the aortic mural is a major characteristic of AAA and is related to AAA formation, development and rupture. Daphnetin (DAP) is a coumarin derivative with anti-inflammatory properties that is extracted from Daphne odora var. However, the effect of DAP on AAA development remains unclear. The present study investigated the effect of DAP on the formation and development of experimental AAAs and its potential underlying mechanisms. A mice AAA model was established by intra-aortic infusion of porcine pancreatic elastase (PPE), and mice were intraperitoneally injected with DAP immediately after PPE infusion. The maximum diameter of the abdominal aorta was measured by ultrasound system, and aortic mural changes were investigated by Elastica van Gieson (EVG) staining and immunohistochemical staining. The results demonstrated that DAP significantly suppressed PPE-induced AAA formation and attenuated the depletion of aortic medial elastin and smooth muscle cells in the media of the aorta. Furthermore, the density of mural macrophages, T cells and B cells were significantly attenuated in DAP-treated AAA mice. In addition, treatment with DAP resulted in a significant reduction in mural neovessels. These findings indicated that DAP may limit the formation and progression of experimental aneurysms by inhibiting mural inflammation and angiogenesis. These data confirmed the translational potential of DAP inclinical AAA inhibition strategies.

LncRNA NEAT1 promotes apoptosis and inflammation in LPS-induced sepsis models by targeting miR-590-3p

Sepsis is a complication of infection caused by disease or trauma. Increasing evidence have shown that long noncoding RNAs (lncRNAs) are involved in the regulation of sepsis. However, the mechanism of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in the regulation of sepsis progression remains to be elucidated. Lipopolysaccharide (LPS) was used to induce a sepsis cell model. The expression levels of NEAT1 and microRNA (miR)-590-3p were determined by reverse transcription-quantitative PCR. Cell viability and apoptosis were detected using Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot analysis was performed to evaluate the levels of apoptosis- and NF-κB signaling pathway-related proteins. The concentration of inflammatory cytokines was determined using ELISA. In addition, dual-luciferase reporter assay, RNA immunoprecipitation and biotin-labeled RNA pull-down assay were performed to verify the interaction between NEAT1 and miR-590-3p. The results showed that NEAT1 was highly expressed in patients with sepsis and LPS-induced H9c2 cells. Knockdown of NEAT1 decreased LPS-induced cell apoptosis and inflammation response in H9c2 cells. Meanwhile, miR-590-3p showed decreased expression in sepsis, and its overexpression could relieve LPS-induced H9c2 cell damage. Further experiments revealed that NEAT1 could sponge miR-590-3p. Knockdown of miR-590-3p reversed the inhibitory effect of NEAT1 knockdown on LPS-induced H9c2 cell damage. Additionally, the NEAT1/miR-590-3p axis could regulate the activity of the NF-κB signaling pathway. To conclude, lncRNA NEAT1 accelerated apoptosis and inflammation in LPS-stimulated H9c2 cells via sponging miR-590-3p. These findings may provide a new strategy for the treatment of sepsis.

Daphnetin induces apoptosis in fibroblast-like synoviocytes from collagen-induced arthritic rats mainly via the mitochondrial pathway

Rheumatoid arthritis (RA) is a chronic, symmetric, systemic autoimmune disease. Because insufficient apoptosis of fibroblast-like synoviocytes (FLS) is an important characteristic of RA, promoting apoptosis is considered a potential therapeutic tool for treating RA. We have previously found that daphnetin (7,8-dihydroxycoumarin, DAP) has a pro-apoptotic effect on fibroblast-like synoviocytes from collagen-induced arthritis (CIA) rats. In the present study, we further investigated the mechanisms of DAP-induced apoptosis in CIA-FLS. CIA-FLS were incubated with DAP for 48 h in the presence or absence of caspase inhibitors, including inhibitors of caspase-3, caspase-8, or caspase-9 or a pan-caspase inhibitor; then, a series of experiments were performed to evaluate the mechanisms of DAP-induced apoptosis. Our results showed that DAP markedly decreased cell viability and induced the apoptosis of CIA-FLS along with typical morphological and ultrastructural changes; moreover, DAP increased FasL, cytochrome c (Cyt-c), Bax, caspase-3, caspase-8, and caspase-9 mRNA expression and Bax, caspase-3, caspase-8, and caspase-9 protein expression. In contrast, DAP decreased Bcl-2 mRNA and protein expression and promoted the release of Cyt-c from the mitochondria into the cytosol; these effects were attenuated to varying degrees by pre-treatment with caspase inhibitors, especially with caspase-3 or caspase-9 inhibitors or a pan-caspase inhibitor. In conclusion, the current findings demonstrate that the DAP-induced apoptosis of CIA-FLS occurred mainly via a caspase-dependent pathway, in particular the mitochondrial pathway, and that the Bax/Bcl-2 ratio was involved in this process. Thus, DAP may be a potential therapeutic agent for RA.

Daphne giraldii Nitsche (Thymelaeaceae): Phytochemistry, pharmacology and medicinal uses

Daphne giraldii Nitsche., a member of the genus Daphne (Thymelaeaceae), is a deciduous shrub with mild toxicity. Its rhizome bark, generally called 'Zushima' in Chinese, has many medicinal folkloric uses and good therapeutic effects. Previous studies investigating the chemical constituents and pharmacological activities of D. giraldii have focused on several major classes of compounds, such as coumarins, lignans and flavonoids, especially the interesting enantiomeric flavans. Extracts and pure compounds of D. giraldii were found to possess anti-inflammatory, anti-nociceptive, cytotoxicity, antimalarial, immunomodulating, sedative and hypnotic effects. They have also been reported to influence the cardiovascular functions and blood activities. This comprehensive review will describe the advances in the phytochemistry, pharmacology, medicinal uses and clinical applications of D. giraldii and its formulations covering the literature published from 1970 to 2018. Almost half of the reviewed studies were originally published in non-English languages (mainly in Chinese). Collectively, the aim of this article is to open new avenues for further in-depth pharmacological studies on D. giraldii.

Tanshinone IIA inhibits proliferation and induces apoptosis of human nasopharyngeal carcinoma cells via p53-cyclin B1/CDC2

Tanshinone IIA exhibits natural antioxidative and antineoplastic activity. However, to the best of our knowledge, the effects of tanshinone IIA on human nasopharyngeal carcinoma cells remains unknown. The present study aimed to investigate whether tanshinone IIA inhibits proliferation and induces apoptosis of human nasopharyngeal carcinoma cells via p53-cyclin B1/cell division cycle gene 2 (CDC2). Cell proliferation, cytotoxicity and apoptosis of 13-9B cells were evaluated by an MTT assay, lactate dehydrogenase assay and flow cytometry, respectively. ELISA and western blot analysis were used to analyze caspase-3 activity and poly (ADP-ribose) polymerase (PARP), p53, cyclin B1 and CDC2 protein expression in 13-9B cells. Treatment of 13-9B cells with tanshinone IIA significantly suppressed cell proliferation and significantly induced cytotoxicity and apoptosis of 13-9B cells. Furthermore, tanshinone IIA significantly increased caspase-3 activity, and significantly increased the protein expression levels of PARP, p53, cyclin B1 and CDC2 in 13-9B cells. In summary, the current results indicate that tanshinone IIA inhibits proliferation and induces apoptosis of human nasopharyngeal carcinoma cells via PARP, p53, cyclin B1/CDC2 and caspase-3-mediated signaling.

Diltiazem aggravates testicular function impairment induced by cyclosporine A or tacrolimus in unilateral nephrectomised rats

The aim of this study was to elucidate the reproductive toxicity of the coadministration of diltiazem and cyclosporine A or tacrolimus. Testicular development, semen quality, sex hormones and testicular tissues were assessed in unilateral nephrectomised (UN) rats, including the control group, UN group, UN+CsA group, UN+FK506 group, UN+Rapa group, UN+CsA+Dil group and UN+FK506+Dil group. The testicular coefficient, the sperm number and the sperm motility were lower in the treatment groups (except UN+FK506) than in the control and UN groups (all p < 0.05). The lowest sperm number and motility were identified in the UN+CsA+Dil group, followed by the UN+CsA group. The proportion of abnormal sperm was higher in the UN+CsA and UN+CsA+Dil groups than in the control and UN groups, respectively (p < 0.05). The plasma concentrations of sex hormones were changed in the treatment groups. Dil can increase the blood concentrations of CsA and FK506 (◇p < 0.05, ◆p < 0.05). Therapeutic doses of these agents induced morphological changes in the testicular tissue and ultrastructural changes in the testosterone, mesenchymal cells and supporting cells. Our present study suggests that Dil can increase the testicular toxicity of CNIs (calcineurin inhibitors, including CsA and FK506) by enhancing the plasma concentrations of CNIs.

Retracted Article: Daphnetin inhibits proliferation and glycolysis in colorectal cancer cells by regulating the PI3K/Akt signaling pathway

Daphnetin (7,8-dihydroxycoumarin), a natural coumarin compound, has shown antitumor and energy metabolism regulatory activities. However, the effects of daphnetin on cell proliferation, migration, and glucose metabolism in colorectal cancer (CRC) cells remains unknown. In this study, the effects of daphnetin on CRC cell proliferation, migration, and glucose metabolism have been examined. The results showed that daphnetin inhibited the proliferation, migration, and invasion of CRC cells, and induced CRC cell apoptosis. Furthermore, daphnetin suppressed intracellular glucose and lactate production, and downregulated the expression of hexokinase 2 (HK2) and glucose transporter 1 (GLUT1) in CRC cells. Furthermore, daphnetin prevented activation of the PI3K/Akt pathway in CRC cells. These findings demonstrated that daphnetin inhibited the proliferation, migration and glucose metabolism in CRC cells by suppressing the PI3K/Akt signaling pathway. Therefore, daphnetin has potential as a novel anticancer agent for CRC treatment.

Knockdown CRNDE alleviates LPS-induced inflammation injury via FOXM1 in WI-38 cells

OBJECTIVE

Pneumonia is the leading global cause of mortality and morbidity in children and elderly people worldwide. The lncRNA colorectal neoplasia differentially expressed (CRNDE) plays an important role in the human development and disease progression. The present study was aimed to investigate the effect of CRNDE on LPS-induced injuries in WI-38 cells and explore the potential mechanism.

METHODS

WI-38 cells were treated with LPS to induce injuries. The expression of CRNDE and FOXM1 in WI-38 cells were altered by transient transfection assay. Cell viability was measured by CCK-8 assay and cell apoptosis was detected by flow cytometry assay and western blot. The levels of inflammatory cytokines were assessed by ELISA and western blot. Furthermore, western blot analysis was performed to detect the expression levels of NF-κB and JAK/STAT pathway-related proteins.

RESULTS

LPS exposure induced cell injuries and increased CRNDE expression in WI-38 cells. CRNDE overexpression enhanced cell injuries in WI-38 cells with significantly reducing cell viability, increasing cell apoptosis and inflammatory cytokines levels. In addition, CRNDE overexpression further activated the NF-κB and JAK/STAT pathways in LPS-injured WI-38 cells. Inversely, opposite results were observed in CRNDE inhibition treatment group. Interestingly, FOXM1 was up-regulated by CRNDE and FOXM1 silence blocked the effect of CRNDE overexpression in cell apoptosis, inflammation and activation of NF-κB and JAK/STAT signaling pathways.

CONCLUSION

This study demonstrated that CRNDE overexpression accelerated LPS-induced apoptosis and inflammation via up-regulation of FOXM1 in WI-38 cells.

Nontargeted SWATH acquisition mode for metabolites identification of osthole in rats using ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

Osthole (OST), 7-methoxy-8-isopentenoxycoumarin, is the characteristic constituent found in Cnidium monnieri (L.) Cuss. and possesses excellent pharmacological activities, including anticancer, anti-apoptosis and neuroprotection. In this study, a rapid and reliable method based on ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) and MetabolitePilot2.0™ software with principal component variable grouping (PCVG) filtering was developed to observe probable metabolites of OST firstly. The high resolution mass data were acquired by data-independent acquisition mode (DIA), i.e., sequential window acquisition of all theoretical fragmentation spectra (SWATH), which could significantly improved the hit rate of low-level and trace metabolites. A novel data processing method 'key product ions (KPIs)' were employed for metabolites rapid hunting and identification as an assistant tool. A total of 72 metabolites of OST were detected in vitro and in vivo, including 39 metabolites in rat liver microsomes (RLMs), 20 metabolites in plasma, 32 metabolites in bile, 32 metabolites in urine and 37 metabolites in feces. The results showed that mono-oxidation, demethylation, dehydrogenation, sulfate conjugation and glucuronide conjugation were major metabolic reactions of OST. More significant, oxydrolysis, 3,4-epoxide-aldehylation, phosphorylation, S-cysteine conjugation and N-acetylcysteine conjugation were considered as unique metabolic pathways of OST, and phosphorylation, S-cysteine conjugation and N-acetylcysteine conjugation reactions were characterized in rat biological samples for the first time. Preparation of active metabolites will be greatly helpful in elucidating the potential biological mechanism of OST, and the proposed metabolic pathways of it might provide further understanding of the safety and efficacy of simple coumarins.

Daphnetin Protects against Cerebral Ischemia/Reperfusion Injury in Mice via Inhibition of TLR4/NF-κB Signaling Pathway

Growing evidences indicate that immune-mediated mechanisms contribute to the development of cerebral ischemia/reperfusion (I/R) injury. Daphnetin (DAP) is a coumarin derivative extracted from Daphne odora var., which displays anti-inflammatory properties. However, the effect of DAP on cerebral I/R injury is not yet clear. Recent studies have demonstrated that TLR4/NF-κB signaling pathway takes part in the damaging inflammatory process of cerebral I/R injury. The present study aimed to investigate the effect of DAP on cerebral I/R injury in vivo and its possible mechanisms. DAP was administered before middle cerebral artery occlusion and reperfusion in mice. The neurological scores, cerebral infarct sizes, the levels of inflammatory cytokines, apoptotic neural cells, and the levels of TLR4, NF-κB p65, and IκBα were estimated. The results showed that an obvious improvement of neurological scores and infarct sizes was observed in DAP-treated mice after MCAO/R. DAP treatment decreased the overexpression of TNF-α, IL-1β, and IL-6 and attenuated neural cells apoptosis. Moreover, DAP treatment decreased the TLR4 expression, IκB-α degradation, and nuclear translocation of NF-κB. Taken together, our results suggested that DAP exerted neuroprotective and anti-inflammatory effects on cerebral I/R injury. The potential mechanism was involved in the inhibition of TLR4/NF-κB mediated inflammatory signaling pathway.

Daphnetin inhibits inflammation in the NZB/W F1 systemic lupus erythematosus murine model via inhibition of NF-κB activity

Daphnetin is a compound extracted from Chinese medicinal herbs, which exerts analgesic and anti-inflammatory effects. The present study aimed to investigate the potential therapeutic effect of daphnetin on inflammation in the NZB/W F1 systemic lupus erythematosus (SLE) murine model. Female NZB/WF1 mice (age, 16–18 weeks) were intraperitoneally injected with daphnetin once a day for 12 weeks. It was revealed that daphnetin treatment significantly increased animal survival rates, reduced renal damage and blood urea nitrogen levels, and suppressed serum autoantibody production in the SLE-prone NZB/W F1 mice. In addition, daphnetin treatment significantly decreased the serum levels of tumor necrosis factor-α and interleukin-6, inhibited nuclear factor (NF)-κB activity, suppressed the protein expression of nuclear factor of activated T-cells and promoted A20 protein expression in SLE-prone NZB/W F1 mice. In conclusion, daphnetin inhibited inflammation in the NZB/W F1 murine SLE model via inhibition of NF-κB mediated by upregulation of A20.

Attenuation of exercise effect on inflammatory responses via novel role of TLR4/PI3K/Akt signaling in rat splenocytes

Moderate exercise diminishes proinflammation cytokine production in various types of immune cells, but the intracellular signaling pathways involved are not completely understood. Phosphoinositide 3-kinase (PI3K)/Akt, a crucial downstream protein of toll-like receptor 4 (TLR4), may modulate inflammation. The present study aimed to investigate the effects of exercises on lipopolysaccharide (LPS)-stimulated inflammatory response in splenocytes and to explore potential mechanisms of the PI3K/Akt pathway. Male rats were divided into sedentary and exercise groups. Animals in the exercise group underwent endurance training 30 min/day, 7 days/wk, at the speed of 20 m/min on a treadmill for 1 wk. Here, we showed that exercise 1) attenuated TLR4, 2) increased PI3K/phospho-Akt (p-Akt), and 3) diminished phospho-nuclear factor-κB (p-NF-κB) expression. In addition, administration of splenocytes isolated from trained rats with LPS in vitro showed 1) reduced tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and nitric oxide secretion and 2) decreased splenocyte proliferation. The plasma corticosterone (CCS) level in the exercise group was higher than that in the sedentary group. We confirmed that CCS down-regulated TNF-α and IL-6 secretion in response to LPS in rat splenocytes. Dexamethasone also significantly attenuated LPS-evoked release of TNF-α and IL-6 in a dose-dependent manner. These findings suggested that exercise dampened the secretion of inflammation mediators probably through partial inhibition of TLR4 and p-NF-κB and activation of PI3K/p-Akt expression in the spleen.

Synthesis of α-santonin derived acetyl santonous acid triazole derivatives and their bioevaluation for T and B-cell proliferation

A new series of α-santonin derived acetyl santonous acid 1,2,3-triazole derivatives were synthesised using Huisgen 1,3-dipolar cyclo-addition reaction (click chemistry approach) and evaluated for their in vitro inhibition activity on concanavalin A (ConA) induced T cell proliferation and lipopolysaccharide (LPS) induced B cell proliferation. Among the synthesised series, compounds 2-10 and 19 exhibited significant inhibition against ConA and LPS stimulated T-cell and B-cell proliferation in a dose dependent manner. More significantly compounds 4, 9-10 and 19 exhibited potent inhibition activity with remarkably lower cytotoxicity on the mitogen-induced T cell and B cell proliferation at 1 μM concentration. The compound 6 displayed potent immunosuppressive effects with ∼89% against LPS induced B-cell and ∼83% against ConA stimulated T-cell proliferation at 100 μM concentration without cytotoxicity. Compound 10 was more selective against B cell proliferation and exhibited 81% and 69% suppression at 100 and 1 μM concentration respectively. The present study led to the identification of several santonin analogs with reduced cytotoxicity and strong inhibition activity against the cell proliferation induced by the mitogens.

Daphnetin Alleviates Experimental Autoimmune Encephalomyelitis via Regulating Dendritic Cell Activity

AIMS

Daphnetin, a coumarin derivative extracted from Daphne odora var. marginata, has been reported to have antiinflammatory and immunosuppressive properties. Our previous study indicated that it was able to remarkably suppress the neuroinflammation and suggested its potential application in treating neuroinflammatory diseases. Multiple sclerosis (MS), a Th cell-mediated autoimmune disease, is the most common inflammatory demyelinating disease of the central nervous system (CNS). We examined whether daphnetin treatment can protect mice against experimental autoimmune encephalomyelitis (EAE), an animal model for MS.

METHODS

To assess the effect of daphnetin in neuroinflammatory diseases, the EAE mice were established and treated with daphnetin at 8 mg/kg for 28 days. The severity of neuroinflammation and demyelination in the spinal cords was examined histopathologically. Infiltration of CD4(+) T cells into the CNS was assessed by immunohistochemistry, and the cytokine production was determined by ELISA. Meanwhile, the effect of daphnetin on the activity of dendritic cells (DCs) was evaluated, as assessed by DCs' capability to express surface markers, secrete cytokines, and activate naïve CD4(+) T cells. Furthermore, we explored the molecular mechanisms whereby DAPH regulated DCs' activity and thereby CD4(+) T cell responses.

RESULTS

The administration of daphnetin markedly alleviated the clinical symptoms of EAE and reduced the CNS inflammation and demyelination in experimental mice. Th1 and Th17 cell responses were profoundly repressed in daphnetin-treated EAE mice. Mechanistically, daphnetin treatment significantly repressed the activation, maturation, and antigen-presenting capability of DCs. NF-κB signaling was significantly reduced in daphnetin-treated DCs, along with a concomitant induction of heme oxygenase-1, a negative regulator of inflammatory signaling.

CONCLUSIONS

Our findings for the first time demonstrate the property of daphnetin in regulating DCs' function and subsequently Th development. Given the low or absent toxicity associated with daphnetin, our data may suggest a novel safe and effective approach to control autoimmune neuroinflammation.

Methylation, Glucuronidation, and Sulfonation of Daphnetin in Human Hepatic Preparations In Vitro: Metabolic Profiling, Pathway Comparison, and Bioactivity Analysis

Our previous study demonstrated that daphnetin is subject to glucuronidation in vitro. However, daphnetin metabolism is still poorly documented. This study aimed to investigate daphnetin metabolism and its consequent effect on the bioactivity. Metabolic profiles obtained by human liver S9 fractions and human hepatocytes showed that daphnetin was metabolized by glucuronidation, sulfonation, and methylation to form 6 conjugates which were synthesized and identified as 7-O-glucuronide, 8-O-glucuronide, 7-O-sulfate and 8-O-sulfate, 8-O-methylate, and 7-O-suflo-8-O-methylate. Regioselective 8-O-methylation of daphnetin was investigated using in silico docking calculations, and the results suggested that a close proximity (2.03 Å) of 8-OH to the critical residue Lysine 144 might be the responsible mechanism. Compared with glucuronidation and sulfonation pathways, the methylation of daphnetin had a high clearance rate (470 μL/min/mg) in human liver S9 fractions and contributed to a large amount (37.3%) of the methyl-derived metabolites in human hepatocyte. Reaction phenotyping studies showed the major role of SULT1A1, -1A2, and -1A3 in daphnetin sulfonation, and soluble COMT in daphnetin 8-O-methylation. Of the metabolites, only 8-O-methyldaphnetin exhibited an inhibitory activity on lymphocyte proliferation comparable to that of daphnetin. In conclusion, methylation is a crucial pathway for daphnetin clearance and might be involved in pharmacologic actions of daphnetin in humans.

2-Oxoglutarate-dependent dioxygenases in the biosynthesis of simple coumarins

Coumarins are natural plant products that have been the subject of extensive phytochemical and pharmacological research studies in the past few decades. The core structure of coumarins is derived from the respective cinnamates via ortho-hydroxylation of the aromatic ring, trans/cis isomerization, and lactonization. Various substitution patterns of coumarins have been reported, whereas the biosynthesis of coumarins remains elusive. Ortho-hydroxylation is a key step in simple coumarin biosynthesis as a branch point from the lignin biosynthetic pathway. 2-Oxoglutarate-dependent dioxygenases (2OGDs) from plants convert cinnamate derivatives into simple coumarins through the process of ortho-hydroxylation. This review describes the 2OGDs involved in coumarin biosynthesis and their substrate specificities.