Molecular Targets of Brown Algae Phlorotannins for the Therapy of Inflammatory Processes of Various Origins.

Inflammatory reactions are part of a complex biological response that plays a vital role in the appearance of various stimuli resulting from tissue and cell damage, the invasion of pathogenic bacteria, and the formation of the subsequent adaptive immune response. The production of many triggers and mediators of inflammation, which are inducers of pro-inflammatory factors, is controlled by numerous differentiation programs, through which inflammation is resolved and tissue homeostasis is restored. However, prolonged inflammatory responses or dysregulation of pro-inflammatory mechanisms can lead to chronic inflammation. Modern advances in biotechnology have made it possible to characterize the anti-inflammatory activity of phlorotannins, polyphenolic compounds from brown seaweed, and the mechanisms by which they modulate the inflammatory response. The purpose of this review is to analyze and summarize the results of numerous experimental in vitro and in vivo studies, illustrating the regulatory mechanisms of these compounds, which have a wide range of biological effects on the body. The results of these studies and the need for further research are discussed.

Effects of FOSL1 silencing on osteosarcoma cell proliferation, invasion and migration through the ERK/AP-1 signaling pathway.

Osteosarcoma (OS), as the most frequent primary malignancy of bone, is characterized by the presence of malignant mesenchymal cells. In the current study, our aim was to explore the possible effects Fos-like antigen-1 (FOSL1) had on the silencing regarding OS cell proliferation, invasion, and migration through the activation of the extracellular-signal-regulated kinase (ERK)/activator protein-1 (AP-1) signaling pathway. After the collection of OS on top of already having the adjacent normal tissue samples, the protein positive expression rate of FOSL1 was then measured by implementing the use of immunohistochemistry and discovered that FOSL1 was robustly expressed in OS. Later, to better grasp the impact FOSL1 projects on OS and its underlying mechanism, we determined the OS related genes as well as the ERK/AP-1 signaling pathway related genes expression by using a reverse-transcription quantitative polymerase chain reaction and western blot assay techniques. The results of the aforementioned two experiments revealed that the FOSL1 depletion had downregulated the expression of OS related genes by simultaneously downregulating the ERK/AP-1 signaling pathway. Moreover, cell proliferation, cycle, apoptosis, invasion, and migration of FOS1 were all tested by using a cell counting kit-8 assay, flow cytometry, Transwell assay, and scratch test, and these results presented that silencing of the FOSL1 gene inhibited OS cell proliferation, invasion, and migration. Our findings revealed a novel mechanism by which FOSL1 depletion played a significantly negative role in the OS progression through the regulation of the ERK/AP-1 signaling pathway. Functional suppression of FOSL1 might be a future therapeutic strategy regarding OS.

Role of the TGFß/PDCD4/AP-1 Signaling Pathway in Nasopharyngeal Carcinoma and Its Relationship to Prognosis.

BACKGROUND: The objective of the present study was to evaluate the role of the TGFß/PDCD4/AP-1 pathway in nasopharyngeal carcinoma (NPC) and its relationship to NPC prognosis. METHODS: NPC tissues collected from 66 NPC patients were compared to 17 nasopharyngeal mucosa biopsy specimens collected as normal tissues. Immunohistochemical staining was performed to assess expression of transforming growth factor-ß receptor I (TGFßRI), programmed cell death 4 (PDCD4) and activator protein-1 (AP-1). The Kaplan-Meier method was applied to evaluate NPC patient overall survival (OS) and progression-free-survival (PFS). Cox regression analysis was used to estimate independent prognostic factors for NPC. The human NPC cell line CNE2 was selected and treated with SB431542, an inhibitor of TGFßRI; expression of TGFßRI and PDCD4 in CNE2 cells was determined by western blotting. NPC tissues showed higher expression of TGFßRI and AP-1 but lower expression of PDCD4 than normal tissues (all P < 0.05). RESULTS: The results of Kaplan-Meier analysis showed that TGFßRI-positive patients and AP-1-positive patients had shorter OS and PFS than TGFßRI-negative patients and AP-1-negative patients; additionally, PDCD4-positive patients had higher OS and PFS than PDCD4-negative patients. Cox regression analysis revealed that advanced tumor stage, overexpression of TGFßRI and AP-1, and low expression of PDCD4 were unfavorable factors influencing OS and PFS in NPC patients. Compared with the control group, expression of TGFßRI decreased and that of PDCD4 increased significantly in CNE2 cells treated with the inhibitor (all P < 0.05). These findings indicate that the TGFß/PDCD4/AP-1 pathway may be associated with NPC development and progression. CONCLUSION: High expression of TGFßRI and AP-1 and low expression of PDCD4 may be unfavorable prognostic factors for NPC.

Autoimmune uveitis attenuated in diabetic mice through imbalance of Th1/Th17 differentiation via suppression of AP-1 signaling pathway in Th cells.

Purpose: Inflammation is involved in the pathogenesis of diabetes, however the impact of diabetes on organ-specific autoimmune diseases remains unexplored. Experimental autoimmune uveoretinitis (EAU) is a widely accepted animal model of human endogenous uveitis. In this study, we investigated the effects of diabetic conditions on the development of EAU using a mouse diabetes model. Methods: EAU was induced in wild-type C57BL/6 (WT) mice and Ins2Akita (Akita) mice with spontaneous diabetes by immunization with IRBP peptide. Clinical and histopathological examinations, and analysis of T cell activation state were conducted. In addition, alternations in the composition of immune cell types and gene expression profiles of relevant immune functions were identified using single-cell RNA sequencing. Results: The development of EAU was significantly attenuated in immunized Akita (Akita-EAU) mice compared with immunized WT (WT-EAU) mice, although T cells were fully activated in Akita-EAU mice, and the differentiation into Th17 cells and regulatory T (Treg) cells was promoted. However, Th1 cell differentiation was inhibited in Akita-EAU mice, and single-cell analysis indicated that gene expression associated AP-1 signaling pathway (JUN, FOS, and FOSB) was downregulated not only in Th1 cells but also in Th17, and Treg cells in Akita-EAU mice at the onset of EAU. Conclusions: In diabetic mice, EAU was significantly attenuated. This was related to selective inhibition of Th1 cell differentiation and downregulated AP-1 signaling pathway in both Th1 and Th17 cells.

Royal Jelly and Chlorella vulgaris Mitigate Gibberellic Acid-Induced Cytogenotoxicity and Hepatotoxicity in Rats via Modulation of the PPARα/AP-1 Signaling Pathway and Suppression of Oxidative Stress and Inflammation.

Gibberellic acid (GA3) is a well-known plant growth regulator used in several countries, but its widespread use has negative effects on both animal and human health. The current study assesses the protective effect of royal jelly (RJ) and Chlorella vulgaris (CV) on the genotoxicity and hepatic injury induced by GA3 in rats. Daily oral administration of 55 mg/kg GA3 to rats for 6 constitutive weeks induced biochemical and histopathological changes in the liver via oxidative stress and inflammation. Co-administration of 300 mg/kg RJ or 500 mg/kg CV with GA3 considerably ameliorated the serum levels of AST (aspartate aminotransferase), ALT (alanine aminotransferase), ALP (alkaline phosphatase), γGT (gamma-glutamyl transferase), total bilirubin, and albumin. Lowered malondialdehyde, tumor necrosis factor α (TNF-α), and nuclear factor κB (NF-κB) levels along with elevated SOD (superoxide dismutase), CAT (catalase), and GPx (glutathione peroxidase) enzyme activities indicated the antioxidant and anti-inflammatory properties of both RJ and CV. Also, they improved the histological structure and reduced cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions along with up-regulating peroxisome proliferator activated receptor α (PPARα) and down-regulating activator protein 1 (AP-1) gene expression. Additionally, chromosomal abnormalities and mitotic index were nearly normalized after treatment with RJ and CV. In conclusion, RJ and CV can protect against GA3-induced genotoxicity and liver toxicity by diminishing oxidative stress and inflammation, and modulating the PPARα/AP-1 signaling pathway.

AP-1 signaling pathway promotes pro-IL-1ß transcription to facilitate NLRP3 inflammasome activation upon influenza A virus infection.

NLRP3 inflammasome mainly controls interleukin-1ß (IL-1ß) secretion, leading to cell death called pyroptosis constituting a major antiviral host defense and inflammatory diseases upon viral infection. The RAF-MEK1/2-ERK1/2 cascade and downstream c-Jun/Fos and Activator protein-1 (AP1) signaling pathway control the degree of inflammatory response. Influenza A virus (IAV) infection is known to stimulate NLRP3 inflammasome activation and inflammatory responses. Nevertheless, the detailed mechanism by which IAV induces NLRP3 inflammasome activation involved in transcription of pro-IL-1ß mRNA remains elusive. In our study, we found that IAV infection promotes pro-IL-1ß mRNA transcription and activates NLRP3 inflammasome. Detailed studies reveal that type I interferon (IFN-α/IFN-ß) as well as U0126 (a selective inhibitor of MEK-1 and MEK-2) typically inhibit IAV-mediated NLRP3 inflammasome activation via downregulating pro-IL-1ß mRNA. Moreover, knock-down of c-Jun decreases pro-IL-1ß mRNA and inhibits NLRP3 inflammasome activation upon IAV infection. Overall, the findings uncover that AP-1 signaling pathway promotes NLRP3 inflammasome activation upon IAV infection, which provides a new idea for the therapy of NLRP3 inflammasome-associated inflammatory diseases.

Oxysophocarpine inhibits airway inflammation and mucus hypersecretion through JNK/AP-1 pathway in vivo and in vitro.

Asthma is a high-incidence disease in the world. Oxysophocarpine (OSC), a quinolizidine alkaloid displays various pharmacological functions including anti-inflammation, neuroprotective, anti-virus and antioxidant. Here, we established mice and cell asthmatic model to explore the effects of OSC for asthma treatment. Mice were sensitized and challenged with ovalbumin (OVA) and treated with OSC before challenge. Enzyme-linked immuno sorbent assay (ELISA), hematoxylin and eosin (H&E), periodic acid-schiff (PAS), tolonium chloride staining and immunohistochemical assay were performed. OSC treatment inhibited inflammatory cell infiltration and mucus secretion in the airway, reduced IgE level in mouse serum and decreased IL-4, IL-5 production in bronchoalveolar lavage fluid (BALF). OSC also reduced the spleen index to regulate immune function. Meanwhile, NCI-H292 cells were induced by lipopolysaccharide (LPS) to simulate airway epithelial injury. OSC pretreatment decreased the IL-6 and IL-8 cytokine levels, mucin 5 AC expression, and mucin 5 AC mRNA level in the cell model. Further, OSC suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), and activator protein 1 (AP-1, Fos and Jun). These findings revealed that OSC alleviated bronchial asthma associated with JNK/AP-1 signaling pathway.

TAK1 in the AP-1 pathway is a critical target of Saururus chinensis (Lour.) Baill in its anti-inflammatory action.

ETHNOPHARMACOLOGICAL RELEVANCE: Saururus chinensis (Lour.) Baill (Saururaceae), also known as Asian lizard's tail, is a plant commonly found in East Asia. Its leaves have been used in traditional medicine to treat many diseases such as edema, pneumonia, hypertension, leproma, jaundice, gonorrhea, and rheumatoid arthritis. AIM OF THE STUDY: Based on the efficacies of S. chinensis, the anti-inflammatory effects of this plant and the molecular mechanism were evaluated using the ethanol extract of S. chinensis leaves (Sc-EE). MATERIALS AND METHODS: The production of pro-inflammatory mediators and cytokines in response to Sc-EE was evaluated using Griess and semi-quantitative reverse transcription-polymerase chain reactions. Furthermore, relevant proteins including c-Jun, c-Fos, p38, JNK, ERK, MEK1/2, MKK3/6, MKK4/7, and TAK1 were detected through immunoblotting. RESULTS: Sc-EE diminished production of nitric oxide (NO); decreased expression levels of cyclooxygenase (COX)-2, interleukin (IL)-6, inducible NO synthase (iNOS), and IL-1ß in LPS-stimulated RAW264.7 cells; and attenuated activator protein 1 (AP-1)-mediated luciferase activities. The extract markedly downregulated the phosphorylation of TAK1, upregulated thermal stability of TAK1, and reduced TAK1/AP-1-mediated luciferase activity in LPS-treated RAW264.7 cells and TAK1-overexpressing HEK293T cells. CONCLUSIONS: These results demonstrated that Sc-EE suppresses pro-inflammatory gene expression through blockade of the TAK1/AP-1 pathway in LPS-treated RAW264.7 macrophages, implying that inhibition of TAK1/AP-1 signaling by S. chinensis is a key event in its anti-inflammatory activity.

Anti-photoaging activities of Sorbaria kirilowii ethanol extract in UVB-damaged cells.

Sorbaria kirilowii (Regel) Maxim, a plant found in China, Korea, Japan, and east of Europe, is a common herb used for traditional medicinal purposes. However, its ability to prevent photoaging has not been studied. In this study, we investigated the anti-photoaging functions of an ethanol extract (Sk-EE) of S. kirilowii (Regel) Maxim using human keratinocytes exposed to UVB. First, we analyzed the cytotoxicity of Sk-EE. Then, we determine the expression of genes related to inflammation, collagen degradation, and moisture retention. We also explored the anti-photoaging mechanism of Sk-EE by determining correlated signaling pathways and target molecules using reporter gene assays and immunoblotting analyses. Sk-EE treatment of cells increased hyaluronic acid synthase (HAS), filaggrin (FLG), and collagen type I alpha 1 (COL1A1) expression. Sk-EE dose-dependently inhibited the UVB-induced expression of matrix metalloproteinases (MMPs) 1, 2, 9 and cyclooxygenase (COX)-2 by blocking the activator protein (AP)-1 signaling pathway, in particular the phosphorylation of c-Jun N-terminal kinase (JNK), p38, and extracellular response kinase (ERK). In addition, c-Fos and c-Jun were targeted by Sk-EE. Our results indicate that Sk-EE has anti-inflammatory and skin-protective properties, and could be a candidate to treat signs of photoaging.

Micronized sacchachitin promotes satellite cell proliferation through TAK1-JNK-AP-1 signaling pathway predominantly by TLR2 activation.

BACKGROUND: Ganoderma sp., such as Ganoderma tsugae (GT), play an important role in traditional Chinese medicine. Ganoderma sp. contains several constituents, including Sacacchin, which has recently drawn attention because it can not only enhance the repair of muscle damage but also strengthen the muscle enforcement. Although Ganoderma sp. have a therapeutic effect for neuromuscular disorders, the underlying mechanism remains unclear. This study investigated the effect and underlying molecular mechanism of micronized sacchachitin (mSC) on satellite cells (SCs), which are known as the muscle stem cells. METHODS: The myogenic cells, included SCs (Pax7+) were isolated from tibialis anterior muscles of a healthy rat and were cultured in growth media with different mSC concentrations. For the evaluation of SC proliferation, these cultivated cells were immunostained with Pax7 and bromodeoxyuridine assessed simultaneously. The molecular signal pathway was further investigated by using Western blotting and signal pathway inhibitors. RESULTS: Our data revealed that 200 µg/mL mSC had an optimal capability to significantly enhance the SC proliferation. Furthermore, this enhancement of SC proliferation was verified to be involved with activation of TAK1-JNK-AP-1 signaling pathway through TLR2, whose expression on SC surface was confirmed for the first time here. CONCLUSION: Micronized sacchachitin extracted from GT was capable of promoting the proliferation of SC under a correct concentration.

SMYD2-OE promotes oxaliplatin resistance in colon cancer through MDR1/P-glycoprotein via MEK/ERK/AP1 pathway.

BACKGROUND: SET and MYND domain-containing protein 2 (SMYD2-OE) plays an important role in cancer development through methylating histone and non-histone proteins. However, little is known about the relevance of SMYD2-OE in colon cancer. Moreover, oxaliplatin (L-OHP) is applied as first line for colon cancer chemotherapy, but drug resistance restricts its efficacy. Unexpectedly, the mechanism of L-OHP resistance in colon cancer remains unclear. In this study, we investigated the relationship of SMYD2-OE expression and L-OHP resistance in colon cancer and further explored the underlying mechanism linking SMYD2-OE, L-OHP resistance, and colon cancer. MATERIALS AND METHODS: Expression levels of SMYD2-OE in colon cancer tissues of patients were tested. In vitro and in vivo assays were conducted to explore the function and mechanism of SMYD2-OE in colon cancer sensitivity to L-OHP. RESULTS: SMYD2-OE was overexpressed in colon cancer tissues compared with non-neoplastic tissues and associated with poor prognosis of patients with colon cancer after L-OHP-based chemotherapy. Knockdown of SMYD2-OE increased colon cancer sensitivity to L-OHP in vitro and in vivo. However, SMYD2-OE overexpression promoted L-OHP resistance in colon cancer cell in vitro. In addition, SMYD2-OE could upregulate MDR1/P-glycoprotein expression depending on MEK/ERK/AP-1 signaling pathway activity. CONCLUSION: These results imply that SMYD2-OE promotes L-OHP resistance in colon cancer by regulating MDR1/P-glycoprotein through MEK/ERK/AP-1 signaling pathway, providing a potential strategy to sensitize chemotherapy by SMYD2-OE knockdown in colon cancer treatment.

CXCL12 gene silencing down-regulates metastatic potential via blockage of MAPK/PI3K/AP-1 signaling pathway in colon cancer.

BACKGROUND: To investigate the effect of CXCL12 gene silencing on proliferation,invasion, angiogenesis and the relationship of MAPK/PI3K/AP-1 signaling pathway in colon cancer cells. METHODS: RT-PCR and Western-blot were used to detect the expression of CXCL12 mRNA and protein in four colon cancer cell lines. Human colon cancer cells were transfected with CXCL12 siRNA carrying by Lipofectamine 2000. The expression of CXCL12 protein was confirmed by immunoblotting. WST-1, invasion and angiogenesis assay were used to examine the effect on proliferation, invasion and angiogenesis in colon cancer cells after CXCL12 siRNA silence, respectively. The phosphorylation of MAPK/PI3K/AP-1 protein levels was detected by Western blotting in CXCL12 siRNA suppression DLD-1 cell. RESULTS: CXCL12 mRNA and proteins were only expressed in DLD-1 colon cancer cell lines. CXCL12 siRNA were transfected into DLD-1 cells, the expression CXCL12 proteins was significantly inhibited (P < 0.01), and the proliferation, invasion and angiogenesis of DLD-1 cells were inhibited significantly (P < 0.01). CXCL12 gene silencing resulted in blockage of MAPK, PI3K and AP-1 phosphorylation by CXCL12-induced in DLD-1 colon cancer cell. CONCLUSION: The silencing CXCL12 gene significantly inhibits the proliferation, invasion and angiogenesis ability of some types colon carcinoma cells through down-regulation of MAPK/PI3K/AP-1 signaling pathway.