Search

Transforming growth factor-β (TGF-β) plays a critical role in the pathological processes of various diseases. However, the signaling mechanism of TGF-β in the pathological response remains largely unclear. In this review, we discuss advances in research of Smad7, a member of the I-Smads family and a negative regulator of TGF-β signaling, and mainly review the expression and its function in diseases. Smad7 inhibits the activation of the NF-κB and TGF-β signaling pathways and plays a pivotal role in the prevention and treatment of various diseases. Specifically, Smad7 can not only attenuate growth inhibition, fibrosis, apoptosis, inflammation, and inflammatory T cell differentiation, but also promotes epithelial cells migration or disease development. In this review, we aim to summarize the various biological functions of Smad7 in autoimmune diseases, inflammatory diseases, cancers, and kidney diseases, focusing on the molecular mechanisms of the transcriptional and posttranscriptional regulation of Smad7., (© 2021. The Author(s).)

Objective: GTS-21, a selective α7 nicotinic acetylcholine receptor agonist, has recently been established as a promising treatment for inflammation. However, the detailed molecular mechanism of GTS-21 in suppressing pro-inflammatory cytokine production is only partially explored. The study aimed to analyze cytokine expression suppressed by GTS-21 with lipopolysaccharide (LPS)-induced inflammation in vitro and to gain insights into the role of Akt/NF-κB signaling pathway in this process., Materials and Methods: Cell Counting Kit-8 (CCK-8) assay was performed to detect drug cytotoxicity. RAW 264.7 cells were stimulated with LPS and treated with GTS-21. Interleukin (IL)-1β, IL-6, or tumor necrosis factor (TNF)-α production was detected using enzyme-linked immunosorbent assay. Western blot was used to assess the expression patterns of signal transduction protein. Nuclear translocation of nuclear factor (NF)-κB was analyzed by confocal fluorescence microscopy. In addition, α7 nicotinic acetylcholine receptors (α7 nAChR) were detected on RAW264.7, and the α7 nAChR-specific antagonist was adopted to verify whether the effect of GTS-21 was mediated by α7 nAChR., Results: The CCK-8 assay showed that GTS-21 did not significantly affect cell proliferation. The production of IL-1β, IL-6, and TNF-α decreased after being treated with GTS-21 in LPS-stimulated RAW 264.7 cells. GTS-21 also suppressed LPS-induced phosphorylation of NF-κBp65, IKKα/β, IκBα, and Akt, as well as NF-κB p65 nuclear translocation. Moreover, α7 nAChR was expressed on the surfaces of RAW264.7 cells, and the α7 nAChR-specific antagonist almost completely prohibited the inhibitory effect of GTS-21 on NF-κB activation., Conclusion: These findings indicate that GTS-21 suppresses LPS-induced inflammation by inhibiting the Akt/NF-κB signal pathway through α7 nAChR. GTS-21 has a potential application in inflammatory disease therapy., (Copyright © 2015. Published by Elsevier B.V.)

Aims: Genistein, an isoflavone derivative found in soy, is known as a promising treatment for rheumatoid arthritis (RA). However, the detailed molecular mechanism of genistein in suppression of proinflammatory cytokine production remains ambiguous. The aim of this work was to evaluate the signal pathway by which genistein modulates inflammatory cytokine expression., Materials and Methods: MH7A cells were stimulated with tumor necrosis factor (TNF)-α and incubated with genistein, and interleukin (IL)-1β, IL-6, and IL-8 production was measured by enzyme-linked immunosorbent assay. Nuclear translocation of nuclear factor (NF)-κB was measured by a confocal fluorescence microscopy. The intracellular accumulation of reactive oxygen species (ROS) was monitored using the fluorescent probe 5-6-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate. Signal-transduction protein expression was measured by Western blot., Results: Genistein decreased the secretion of IL-1β, IL-6, and IL-8 from TNF-α-stimulated MH7A cells in a dose-dependent manner. Genistein prevented TNF-α-induced NF-κB translocation as well as phosphorylation of IκB kinase-α/β and IκBα, and also suppressed TNF-α-induced AMPK inhibition. The production of IL-1β, IL-6, and IL-8 induced by TNF-α was decreased by the phosphatidylinositol-3 kinase inhibitor LY294002, suggesting that inhibition of Akt activation might inhibit IL-1β, IL-6, and IL-8 production induced by TNF-α. In addition, we also found that pretreatment with the adenosine monophosphate-activated protein kinase (AMPK) agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside obviously inhibited TNF-α-induced proinflammatory cytokine production. These observations suggest that the inhibitory effect of genistein on TNF-α-induced proinflammatory cytokine production is dependent on AMPK activation., Conclusion: These findings indicate that genistein suppressed TNF-α-induced inflammation by inhibiting the ROS/Akt/NF-κB pathway and promoting AMPK activation in MH7A cells.

Background: Rheumatoid arthritis is a progressive and systemic autoimmune disease seriously compromises human health. Fibroblast like synoviocytes are the major effectors of proliferation and inflammation in rheumatoid arthritis synovial tissue. Shikonin has anti-inflammatory and immunomodulatory activities. But, its role on synovitis of rheumatoid arthritis is unknown. Methods: The DBA/1 male mice were randomly divided into the following three groups (n = 6): (1) the normal control group of mice, (2) the CIA (collagen-induced arthritis) group in which mice suffered from arthritis induced by collagen, (3) the SKN (shikonin) group of mice which got arthritis and given intragastrically with shikonin 4 mg/kg per day continuously for 20 days,(4) the MTX (methotrexate) group of mice which got arthritis and orally administration with shikonin 0.5 mg/kg once two days continuously for 20 days. The therapeutic effect of shikonin on collagen induced arthritis mice was tested by arthritis incidence rate, arthritis score and inflammatory joint histopathology. The invasion, adhesion and migration of fibroblast like synoviocytes induced by tumor necrosis factor-α were applied to measure the anti-synovitis role of shikonin. The effect of shikonin on expression of interleukin-6, interleukin-1β and tumor necrosis factor-α was measured by enzyme linked immunosorbent assay. The interaction between shikonin and suppressor of cytokine signaling 1 was verified by molecular docking. The signaling pathways activated by shikonin were measured by western blot. Results: Shikonin decreased the arthritis score and arthritis incidence, and inhibited inflammation of inflamed joints in collagen induced arthritis mice. And shikonin reduced the number of vimentin+cells in collagen induced arthritis mice inflamed joints. Meanwhile, shikonin suppressed tumor necrosis factor-α-induced invasion, adhesion and migration of fibroblast like synoviocytes and reduced the expression of interleukin-6, interleukin-1β and tumor necrosis factor-α. And we found that shikonin targeted suppressor of cytokine signaling 1. More interestingly, shikonin blocked the phosphorylation of Janus kinase 1/signal transducer andactivator of transcription 1/signal transducer andactivator of transcription 6 in synovial tissues and in fibroblast like synoviocytes. Conclusion: Shikonin represents a promising new anti-rheumatoid arthritis drug candidate that has anti-synovitis effect in collagen induced arthritis mice and inhibits tumor necrosis factor-α-induced fibroblast like synoviocytes by targeting suppressor of cytokine signaling 1/ Janus kinase/signal transducer andactivator of transcription signaling pathway. These findings demonstrate that shikonin has anti-synovitis effect and has great potential to be a new drug for the treatment of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder that may affect many tissues and organs. Without treatment, inflammation leads to cartilage damage, bone erosions, joint destruction, and impaired movement. Because of the limited success of disease-modifying anti-rheumatic drugs, the exploration of new anti-rheumatic drugs with high efficacy and less toxicity is eagerly needed. Genistein, the major active compound from soybean, has received much attention due to its potential beneficial effects on some of the degenerative diseases. It has been found that genistein has anti-inflammatory, antiangiogenesis, antiproliferative, antioxidant, immunomodulatory, pain relief, and joint protection properties. Hence, significant advances have been made, both by in vitro and in vivo studies showing that genistein is a promising agent for RA treatment. [ABSTRACT FROM AUTHOR]