Search

Nuclear receptors are a superfamily of transcription factors that regulate gene transcription and intracellular function. They have a key role in various biological processes. Liver X receptors (LXR) mainly play role in lipid metabolism, cholesterol synthesis, glucose homeostasis, and inflammation whereas retinoid X receptor alpha (RXRa) plays important role in inflammation and immunity. In this study, Plantago holosteum, P. major subsp. major, P. lagopus, P. scabra, and Scutellaria salviifolia were selected for further investigation due to their anti-inflammatory activities. For this purpose, liver x receptor alpha (LXRa) and retinoid x receptor alpha (RXRa) agonist activity of the extracts was determined through luciferase reporter gene assay on HEK293 cells at a concentration of 100 µg/ml. P. holosteum, P. major subsp. major, P. lagopus, and P. scabra extracts showed weak LXRa agonist activity with the fold values in a range of 0.95-1.39. P. major showed the highest agonist activity among tested Plantago species. For LXRa agonist activity, S. salviifolia extract had a fold value of 2.37 which was comparable to the positive control T09011317 at 10 nM concentration. Results for RXRa agonist activity found to be similar to LXRa for all extracts. S. salviifolia showed the highest RXRa agonist activity with a fold value of 1.62. Results suggested that Scutellaria species, which are used as traditional medicine especially in eastern Asia due to its anti-inflammatory effects, might show this effect due to LXRa activation. [ABSTRACT FROM AUTHOR]

(1) Background: Ranunculus bulumei is a flowering plant that belongs to the Ranunculus species. Several Ranunculus species, such as R. aquatilis and R. muricatus, have traditionally been used to treat fever and rheumatism throughout Asia, suggesting that plants belonging to the Ranunculus species may have anti-inflammatory effects. To our knowledge, the pharmacological activity of R. bulumei has not been reported. Therefore, in this study, we aim to assess the anti-inflammatory activity of a methanol extract that was derived from R. bulumei (Rb-ME) in macrophage-mediated inflammatory responses and to identify the molecular mechanism that underlies any anti-inflammatory action. (2) Methods: The anti-inflammatory efficacy of Rb-ME was evaluated while using in vitro and in vivo experiments. The RAW264.7 cells and peritoneal macrophages were stimulated by lipopolysaccharide (LPS). In addition, LPS-induced peritonitis and HCl/EtOH-triggered gastritis models were produced. A nitric oxide (NO) assay, real-time PCR, luciferase reporter gene assay, western blot analysis, plasmid overexpression strategy, and in vitro kinase assay were used to determine the molecular mechanisms and target molecules of Rb-ME. The phytochemical active ingredients of Rb-ME were also identified by high performance liquid chromatograph (HPLC). (3) Results: Rb-ME reduced the production of NO and mRNA expression of iNOS, COX-2, IL-1β, and IL-6 without cytotoxicity. The protein secretion of TNF-α and IL-6 was also decreased by Rb-ME. HPLC analysis indicates that quercetin, luteolin, and kaempferol are the main active ingredients in the anti-inflammatory efficacy of Rb-ME. Rb-ME also blocked MyD88-induced NF-κB promoter activity and nuclear translocation of NF-κB subunits (p65 and p50). Moreover, Rb-ME reduced the phosphorylation of IκBα, Akt, p85, Src, and Syk, which are NF-κB upstream signaling molecules in LPS-activated RAW264.7 cells. According to the in vitro kinase assay, Rb-ME directly inhibits Syk kinase activity. The oral administration of Rb-ME alleviated inflammatory responses and the levels of p-IκBα in mice with LPS-induced peritonitis and HCl/EtOH-induced gastritis. (4) Conclusions Rb-ME has anti-inflammatory capacity by suppressing NF-κB signaling and it has been found to target Src and Syk in the NF-κB pathway. Based on this efficacy, Rb-ME could be developed as an anti-inflammatory herbal medicine. [ABSTRACT FROM AUTHOR]

• A birch ERF transcription factor, BpERF13 , which positively responds and regulates cold stress, was cloned and functionally characterized. • Transgenic lines overexpressing BpERF13 exhibited normal phenotypes except for a significantly augmented tolerance to cold stress. • BpERF13 augmented cold tolerance in transgenic lines through upregulating two CBF genes and four reactive oxygen species scavenging genes. The AP2/ERF (APETALA2/ethylene-responsive factor) family of transcription factors (TF) is involved in regulating biotic and abiotic stress responses in plants. To explore the role of AP2/ERFs in cold tolerance in woody plants, BpERF13 was cloned and characterized in Betula platyphylla (white birch), a species primarily found in Asia in temperate and boreal climates. Based on phylogenetic analysis, BpERF13 is a member of the IXb subfamily of ERFs. Using qRT-PCR, we found that BpERF13 was differentially expressed in different tissues, and its expression could be induced by cold treatment (4 °C). BpERF13 protein, fused with GFP, was exclusively localized to nuclei. To further assess the role of BpERF13 in cold tolerance, BpERF13 overexpression (OE) transgenic lines were generated in B. platyphylla and used for cold stress treatment and biochemical/physiological studies. BpERF13 overexpression lines had significantly increased tolerance to subfreezing treatment and reduced reactive oxygen species. Using a TF-centered yeast one-hybrid (Y1H) experimental system, we showed that BpERF13 could bind to LTRECOREATCOR15 and MYBCORE cis-elements to activate a reporter gene. ChIP-seq and ChIP-PCR experiments further demonstrated that BpERF13 bound to these cis-elements when present in the 5′ proximal regions of superoxide dismutase (SOD), peroxidase (POD), and C-repeat-binding factor (CBF) genes. qRT-PCR was employed to examine the expression levels of these genes in response to cold stress; SOD, POD, and CBF genes were significantly upregulated in BpERF13 transgenic lines compared to wild-type plants in response to cold stress. These results indicate that the transcription factor BpERF13 regulates physiological processes underlying cold tolerance in woody plants. [ABSTRACT FROM AUTHOR]