Signal transduction through NF-kappa B

Proteomic analysis reveals the molecular mechanism of Hippophae rhamnoides polysaccharide intervention in LPS-induced inflammation of IPEC-J2 cells in piglets

Early weaning can cause intestinal disorders and dysfunction in piglets, and may induce intestinal diseases. Hippophae rhamnoides polysaccharide (HRP) has anti-inflammatory and immune promotion function. However, few studies have explored the change of differentially protein expression by lipopolysaccharide (LPS)-induced porcine intestinal epithelial cell (IPEC-J2) after HRP pre-treatment. In this study, proteomic analysis was used to explore the essential proteins and immune-related pathways that can be regulated by LPS-induced IPEC-J2 cells after HRP pre-treatment. The results indicate that by searching the Sus scrofa database, a total of 18,768 proteins was identified. Among recognized proteins, there are 2052 (1720 up-regulated and 332 down-regulated), 358 (262 up-regulated and 96 down-regulated) and1532 (314 up-regulated and 1218 down-regulated) proteins expressed differently in C vs. L, C vs. H6-L and L vs. H6-L, respectively. The Cluster of Orthologous Groups (COG) analysis divided the identified proteins into 23 categories. Gene Ontology (GO) enrichment analysis revealed that cellular process, cell, cell part, organelle and binding were the most enriched pathways for differentially expressed proteins. KEGG enrichment analysis indicated that the top 20 pathways in the L-vs-H6-L group related to immunity were the Tight junction, MAPK signaling pathway, PI3K-Akt signaling pathway, rap1 signaling pathway, HIF-1 signaling pathway, Ras signaling pathway and Fc gamma R-mediated phagocytosis. Moreover, we also found 42 key proteins related to these immune pathways in this study. Additionally, western blotting analyses confirmed that LPS reduced the levels of claudin2 (CLDN2), insulin-like growth factor 2 (IGF2) and increased phosphorylated mitogen-activated protein kinase 7 (MAPK7), phosphorylated transcription factor p65 (RELA), phosphorylated nuclear factor NF-kappa-B p105 subunit (NF-κB1) and phosphorylated nuclear factor of kappa light polypeptide gene enhancer in B-cells 2 (NF-κB2). Pre-treatment with HRP increased the levels of CLDN2, IGF2 and reduced the levels of the phosphorylated MAPK7, phosphorylated RELA, phosphorylated NF-κB1 and phosphorylated NF-κB2 in cells. These results also showed that HRP alleviated LPS-induced inflammation in IPEC-J2 cells by inhibiting the MAPK/NF-κB signaling pathway and its related differentially expressed proteins.

Use of Adrenocorticotropic Hormone in Ophthalmology

The ability of the adrenocorticotropic hormone (ACTH) to induce steroidogenesis and upregulate anti-inflammatory processes has long been known. More recently, however, extrasteroidal mechanisms, through which ACTH exerts anti-inflammatory processes, have been described. This has renewed hope that ACTH can combat inflammatory conditions even when resistant to steroids. This review article summarizes the literature on the use of ACTH in ocular disease. Unfortunately, much of the data regarding the clinical utility of ACTH are outdated, with many studies published in the 1950s and 1960s. Many of these older studies are inconsistent or incomplete with their reporting, making it difficult to ascertain the meaning of the outcomes. Despite the limitations, 2 important trends are evident. First, when used to treat an inflammatory disease, ACTH can be effective at decreasing or eliminating ocular inflammation, even in a refractory disease resistant to multiple treatment modalities. Second, adverse effects of ACTH are rare and are most likely to be reported with relatively high doses of ACTH therapy. Taken as a whole, these studies offer initial promising data that ACTH may be a safe and effective alternative in refractory ocular inflammatory disease. However, they highlight an important lack of prospective data to more rigorously understand the true safety and efficacy of this therapy.

Heat Shock Protein 70 as a Double Agent Acting Inside and Outside the Cell: Insights into Autoimmunity

Heat shock proteins (Hsp) are a diverse group of constitutive and/or stress-induced molecules that are categorized into several classes on the basis of their molecular weight. Mammalian Hsp have been mostly regarded as intracellular chaperones that mediate a range of essential cellular functions, including proper folding of newly synthesized polypeptides, refolding of denatured proteins, protein transport, and stabilization of native proteins' structures. The well-characterized and highly evolutionarily conserved, stress-inducible 70-kDa heat shock protein (Hsp70), is a key molecular chaperone that is overexpressed in the cell in response to stress of various origin. Hsp70 exhibits an immunosuppressive activity via, e.g., downregulation of the nuclear factor-kappa B (NF-κB) activation, and pharmacological induction of Hsp70 can ameliorate the autoimmune arthritis development in animal models. Moreover, Hsp70 might be passively or actively released from the necrotic or stressed cells, respectively. Highly immunogenic extracellular Hsp70 has been reported to impact both the innate and adaptive immune responses, and to be implicated in the autoimmune reaction. In addition, preclinical studies revealed that immunization with highly conserved Hsp70 peptides could be regarded as a potential treatment target for autoimmune arthritis, such as the rheumatoid arthritis, via induction of antigen-specific regulatory T helper cells (also called Treg). Here, a dual role of the intra- and extracellular Hsp70 is presented in the context of the autoimmune reaction.

Naringin Targets NFKB1 to Alleviate Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury in PC12 Cells Via Modulating HIF-1α/AKT/mTOR-Signaling Pathway

This study was designed to investigate the effect of naringin in oxygen-glucose deprivation/reoxygenation (OGD/R) model and its mechanism. The target gene of naringin and the enriched pathways of the gene were searched and identified using bioinformatics analysis. Then OGD/R model was built using PC12 cells, after which the cells were treated with different concentrations of naringin. Subsequently, cell proliferation and apoptosis were evaluated by cell counting kit-8 (CCK-8) and flow cytometry assays, respectively. Meanwhile, the expression of NFKB1 in PC12 cells underwent OGD/R-induced injury was detected by qRT-PCR, while apoptosis-related and pathway-related proteins were checked by Western blot. DCF-DA kit was utilized to measure the level of ROS. Our results revealed that NFKB1, which was upregulated in MACO rats and OGD/R-treated PC12 cells, was a target gene of naringin. Naringin could alleviate OGD/R-induced injury via promoting the proliferation, and repressing the apoptosis of PC12 cells through regulating the expression of NFKB1 and apoptosis-associated proteins and ROS level. Besides, the depletion of NFKB1 was positive to cell proliferation but negative to cell apoptosis. Moreover, the depletion of NFKB1 enhanced the influences of naringin on cell proliferation and apoptosis as well as the expression of apoptosis-related proteins and ROS level. Western blotting indicated that both naringin treatment and depletion of NFKB1 could increase the expression of HIF-1α, p-AKT, and p-mTOR compared with OGD/R group. What's more, treatment by naringin and si-NFKB1 together could significantly increase these effects. Nevertheless, the expression of AKT and mTOR among each group was almost not changed. In conclusion, naringin could prevent the OGD/R-induced injury in PC12 cells in vitro by targeting NFKB1 and regulating HIF-1α/AKT/mTOR-signaling pathway, which might provide novel ideas for the therapy of cerebral ischemia-reperfusion (I/R) injury.

Oxidative stress and diabetes: antioxidative strategies

Diabetes mellitus is one of the major public health problems worldwide. Considerable recent evidence suggests that the cellular reduction-oxidation (redox) imbalance leads to oxidative stress and subsequent occurrence and development of diabetes and related complications by regulating certain signaling pathways involved in β-cell dysfunction and insulin resistance. Reactive oxide species (ROS) can also directly oxidize certain proteins (defined as redox modification) involved in the diabetes process. There are a number of potential problems in the clinical application of antioxidant therapies including poor solubility, storage instability and nonselectivity of antioxidants. Novel antioxidant delivery systems may overcome pharmacokinetic and stability problem and improve the selectivity of scavenging ROS. We have therefore focused on the role of oxidative stress and antioxidative therapies in the pathogenesis of diabetes mellitus. Precise therapeutic interventions against ROS and downstream targets are now possible and provide important new insights into the treatment of diabetes.

Protein-protein interactions of ER-resident selenoproteins with their physiological partners

ER is a highly specialized complex of branched microtubules enclosed in a membrane and communicating with each other, its functions in the cell are important and very diverse: lipid and phospholipid synthesis, calcium storage, hormone synthesis, protein synthesis and maturation, membrane production, toxin neutralization, etc. The high concentration of calcium ions and the oxidizing properties of the contents of the ER cavities contribute to the proper synthesis and folding of proteins designed for secretion or exposure on the surface of the cell membrane. However, disturbance of redox regulation can lead to the accumulation of improperly folded proteins in the ER, disruption of calcium regulation, which can cause ER-stress. This review is devoted to the role of ER-resident selenoproteins in the processes occurring in this organelle of a cell. The main emphasis is placed on the study of protein-protein interactions of selenoproteins with their physiological partners; this will facilitate understanding of their functional purpose in this organelle. Currently, 7 selenoproteins are known that are localized in the ER, but the functions of most of them are not at all clear, for some, physiological partners have been identified. It is known that selenoproteins are oxidoreductases with antioxidant properties, this is extremely important for the normal functioning of ER. Therefore, this review can be very useful for understanding the full picture of the functions of ER-resident selenoproteins obtained on the basis of recent data.

Early astragaloside IV administration attenuates experimental autoimmune encephalomyelitis in mice by suppressing the maturation and function of dendritic cells

AIMS

Dendritic cells (DCs) actively participate in the pathogenesis of multiple sclerosis (MS), an autoimmune disease. Astragaloside IV (ASI), an active monomer isolated from the Chinese medicine Astragalus membranaceus, has a wide range of pharmacological effects. We aimed to elucidate the effects of ASI on the development of DCs in the early stage of MS/EAE.

MAIN METHODS

The mice were administered with ASI (20 mg/kg) daily 3 days in advance of EAE induction and continuously until day 7 post-immunization. The effect of ASI on CD11c⁺ DC cells from bone marrow (BMDCs) or the spleen of EAE mice at day 7 post-immunization were investigated respectively by flow cytometry, ELISA, western blot, real-time PCR and immunofluorescence.

KEY FINDINGS

ASI administration in the early stage of EAE was demonstrated to delay the onset and alleviate the severity of the disease. ASI inhibited the maturation and the antigen presentation of DCs in spleen of EAE mice and LPS-stimulated BMDCs, as evidenced by decreased expressions of CD11c, CD86, CD40 and MHC II. Accordingly, DCs treated by ASI secreted less IL-6 and IL-12, and prevented the differentiation of CD4⁺ T cells into Th1 and Th17 cells, which was probably through inhibiting the activation of NFκB and MAPKs signaling pathways.

SIGNIFICANCE

Our results implicated the alleviative effect of early ASI administration on EAE might be mediated by suppressing the maturation and function of DCs. The novel findings may add to our knowledge of ASI in the potentially clinical treatment of MS.

Expression of genes involved in the NF-κB-dependent pathway of the fibrosis in the mare endometrium

Equine endometrosis is a multifactorial chronic degenerative condition, considered to be one of a major causes of equine infertility. The formation of periglandular fibrosis seems to be linked to chronic inflammation of the mare endometrium in a paracrine way and in a response to numerous forms of inflammatory stimuli elicit the net deposition of extracellular matrix (ECM) around the endometrial glands and stroma. We hypothesized some of these stimuli, such as monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), and hyaluronan synthases (HASs), may share the nuclear factor-κB (NF-κB) dependent activation pathway. This study aimed to determine whether mRNA expression of MCP-1, IL-6, HASs, and proteins of canonical (RelA/NK-κβ1) and noncanonical (NK-κβ2) signaling pathways for NF-kB would change in subsequent categories of endometrosis during the estrous cycle. The expression of selected genes was established in mare endometrium (n = 80; Kenney and Doig categories I, IIA, IIB, III), obtained in the follicular phase (FLP) and mid-luteal phase (MLP). The high expression of RelA mRNA was observed in III, whereas of NK-κβ1 and NK-κβ2 also in IIA, and IIA and IIB, respectively. The expression of MCP-1 mRNA occurred constantly, regardless of the category, whereas IL-6 mRNA was low in IIA, IIB, and III. The expression of HAS 1 was high in IIA and HAS 3 in IIA, IIB, and III. All those changes were observed in FLP, but not MLP. Our results suggest that NF-κB may be involved in progression of the chronic degenerative condition of the mare endometrium, on both canonical and noncanonical pathways. The most important changes in target genes expression were observed only in FLP, which may suggest the hormone-dependent activation of the NF-κB-dependent fibrosis pathway.

Genome-wide analysis of mRNAs and lncRNAs in Mycoplasma bovis infected and non-infected bovine mammary gland tissues

Mycoplasma bovis (M. bovis) causes diseases such as arthritis, pneumonia, abortion, and mastitis, leading to great losses in the bovine dairy industries. RNA types such as messenger RNAs (mRNAs) and long non-coding RNAs (lncRNAs) play significant roles in regulating the immune responses triggered by bacteria. The expression profiles of mRNA and lncRNA as they occur in bovine mammary gland tissues infected with M. bovis are still not well understood. To illuminate this issue, transcription analysis of mRNA and LncRNAs were conducted on the mammary gland tissues belonging to Holstein cattle infected and not infected with M. bovis. The analysis revealed 1310 differentially expressed mRNAs and 57 differentially expressed lncRNAs in the bovine mammary gland tissues infected and not infected with M. bovis. In addition, 392 novel lncRNAs were detected, 19 of which were differentially expressed. Gene ontology analysis reveals that differentially expressed mRNAs and lncRNAs play significant roles in such vital biological pathways as metabolic pathways, T-cell receptor signaling, TGF-beta signaling, pathways in cancer, PI3K-Akt signaling, NF-kappa B signaling, mTOR signaling, and apoptosis, including in the immune response to cancer. Based on our literature review, this study is the first genome-wide lncRNA research conducted on bovine mammary gland tissues infected with M. bovis. Our results provide bovine mammary gland lncRNA and mRNA resources to understand their roles in the regulation of the immune response against the agent M. bovis in bovine mammary gland tissues.

C13 Megastigmane Derivatives From Epipremnum pinnatum: β-Damascenone Inhibits the Expression of Pro-Inflammatory Cytokines and Leukocyte Adhesion Molecules as Well as NF-κB Signaling

In order to identify active constituents and to gain some information regarding their mode of action, extracts from leaves of Epipremnum pinnatum were tested for their ability to inhibit inflammatory gene expression in endothelial- and monocyte-like cells (HUVECtert and THP-1, respectively). Bioactivity-guided fractionation using expression of PTGS2 (COX-2) mRNA as a readout resulted in the isolation of two C13 megastigmane glycosides, gusanlungionoside C (1) and citroside A (3), and the phenylalcohol glycoside phenylmethyl-2-O-(6-O-rhamnosyl)-ß-D-galactopyranoside (2). Further analysis identified six additional megastigmane glycosides and the aglycones β-damascenone (10), megastigmatrienone (11), 3-hydroxy-β-damascenone (12), and 3-oxo-7,8-dihydro-α-ionol (13). Pharmacological analysis demonstrated that 10 inhibits LPS-stimulated induction of mRNAs encoding for proinflammatory cytokines and leukocyte adhesion molecules, such as TNF-α, IL-1β, IL-8, COX-2, E-selectin, ICAM-1, and VCAM-1 in HUVECtert and THP-1 cells. 10 inhibited induction of inflammatory genes in HUVECtert and THP-1 cells treated with different agonists, such as TNF-α, IL-1β, and LPS. In addition to mRNA, also the upregulation of inflammatory proteins was inhibited by 10 as demonstrated by immune assays for cell surface E-selectin and secreted TNF-α. Finally, using a luciferase reporter construct, it was shown, that 10 inhibits NF-κB-dependent transcription. Therefore, we hypothesize that inhibition of NF-κB by β-damascenone (10) may represent one of the mechanisms underlying the in vitro anti-inflammatory activity of Epipremnum pinnatum extracts.

Berberine ameliorates lipopolysaccharide‑induced inflammatory responses in mouse inner medullary collecting duct‑3 cells by downregulation of NF‑κB pathway

The major role of inner medullary collecting duct (IMCD) cells is to maintain water and sodium homeostasis. In addition to the major role, it also participates in the protection of renal and systemic inflammation. Although IMCD cells could take part in renal and systemic inflammation, investigations on renal inflammation in IMCD cells have rarely been reported. Although berberine (BBR) has been reported to show diverse pharmacological effects, its anti-inflammatory and protective effects on IMCD cells have not been studied. Therefore, in the present study, we examined the anti-inflammatory and protective effects of BBR in mouse IMCD-3 (mIMCD-3) cells against lipopolysaccharide (LPS). An MTT assay was carried out to investigate the toxicity of BBR on mIMCD-3 cells. Reverse transcription quantitative-PCR and western blotting were performed to analysis pro-inflammatory molecules and cytokines. Mechanisms of BBR were examined by western blotting and immunocytochemistry. According to previous studies, pro-inflammatory molecules, such as inducible nitric oxide synthase and cyclooxygenase-2, and pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6 and tumor necrosis factor-α are increased in LPS-exposed mIMCD-3 cells. However, the production of these pro-inflammatory molecules is significantly inhibited by treatment with BBR. In addition, BBR inhibited translocation of nuclear factor (NF)-κB p65 from the cytosol to the nucleus, and degradation of inhibitory κ-Bα in LPS-exposed mIMCD-3 cells. In conclusion, BBR could inhibit renal inflammatory responses via inhibition of NF-κB signaling and ultimately contribute to amelioration of renal injury during systemic inflammation.

Late-Onset Antibody Deficiency Due to Monoallelic Alterations in NFKB1

Adult-onset primary immunodeficiency is characterized by recurrent infections, hypogammaglobulinemia, and poor antibody response to vaccines. In this study, we have analyzed targeted gene panel sequencing results of 270 patients diagnosed with antibody deficiency and identified five disease-associated variants in NFKB1 in five unrelated families. We detected two single base pair deletions and two single base pair insertions, causing severe protein truncations, and one missense mutation. Immunoblotting, lymphocyte stimulation, immunophenotyping, and ectopic expression assays demonstrated the functional relevance of NFKB1 mutations. Besides antibody deficiency, clinical manifestations included infections, autoimmune features, lymphoproliferation, lymphoma, Addison's disease, type 2 diabetes and asthma. Although partial clinical penetrance was observed in almost all pedigrees, all carriers presented a deficiency in certain serum immunoglobulins and the majority showed a lack of memory B cells (CD19⁺CD27⁺). Among all tested genes, NFKB1 alterations were the most common monoallelic cause of antibody deficiency in our cohort.

The potential therapeutic actions of melatonin in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and lethal disease worldwide. Melatonin, an indoleamine produced in pineal gland, shows anticancer effects on a variety of cancers, especially CRC. After clarifying the pathophysiology of CRC, the association of circadian rhythm with CRC, and the relationship between shift work and the incidence of CRC is reviewed. Next, we review the role of melatonin receptors in CRC and the relationship between inflammation and CRC. Also included is a discussion of the mechanism of gene regulation, control of cell proliferation, apoptosis, autophagy, antiangiogenesis and immunomodulation in CRC by melatonin. A review of the drug synergy of melatonin with other anticancer drugs suggests its usefulness in combination therapy. In summary, the information compiled may serve as comprehensive reference for the various mechanisms of action of melatonin against CRC, and as a guide for the design of future experimental research and for advancing melatonin as a therapeutic agent for CRC.

Salmonella Fimbrial Protein FimH Is Involved in Expression of Proinflammatory Cytokines in a Toll-Like Receptor 4-Dependent Manner

Type 1 fimbriae are proteinaceous filamentous structures present on bacterial surfaces and are mainly composed of the major fimbrial protein subunit FimA and the adhesive protein FimH, which is located at the tip of the fimbrial shaft. Here, we investigated the involvement of type 1 fimbriae in the expression of proinflammatory cytokines in macrophages infected with Salmonella enterica serovar Typhimurium. The level of interleukin-1β (IL-1β) mRNA was lower in macrophages infected with fimA or fimH mutant strains than in those infected with wild-type Salmonella Treatment of macrophages with purified recombinant FimH protein, but not FimA, resulted in the activation of the mitogen-activated protein kinase and nuclear factor κB signaling pathways, leading to the expression of not only IL-1β but also other proinflammatory cytokines, such as IL-6 and tumor necrosis factor alpha. However, FimH carrying an N-terminal region deletion or heat-treated FimH did not show such effects. The expression of FimH-induced IL-1β was inhibited by treatment with the Toll-like receptor 4 (TLR4) inhibitor TAK-242 but not by treatment with polymyxin B, a lipopolysaccharide antagonist. Furthermore, FimH treatment stimulated HEK293 cells expressing TLR4 and MD-2/CD14 but did not stimulate HEK293 cells expressing only TLR4. Collectively, FimH is a pathogen-associated molecular pattern of S. enterica serovar Typhimurium that is recognized by TLR4 in the presence of MD-2 and CD14 and plays a significant role in the expression of proinflammatory cytokines in Salmonella-infected macrophages.

Evaluation of rs1957106 Polymorphism of NF-κBI in Glioblastoma Multiforme in Isfahan, Iran

BACKGROUND

The kB family of nuclear factor (NF-κB) is a series of transcription factors that plays a key role in regulation of immunity, cell growth, and apoptosis and is considered as the main downstream component of epidermal growth factor receptor for which there are evidence of excessive activity in most cases of glioblastoma multiform (GBM). Thus, the current information has gained evidence on NF-κBIA tumor suppressor role in GMB. SNP rs1957106 was diagnosed as a new polymorphism which affected the expression of NF-κBI and causes activation of NF-κB in GBM patients.

MATERIALS AND METHODS

This study was conducted on 100 cases of GBM including 47 paraffin-embedded brain tissue samples and 53 blood samples from another 53 GBM patients and 150 controls. The NF-κBI rs1957106 SNP was identified by the NCBI, and genotyping was performed by high-resolution melt (HRM) assay. Melt curves from HRM which suspected to single-nucleotide polymorphism (SNP) were selected and subjected to direct sequencing.

RESULTS

The distribution of allele A of NF-κβ gene in patients with GBM with 31% was not significantly different from healthy participants (27.3%) (P = 0.375). Furthermore, the distribution of AG and GG genotypes in comparison with AA genotypes did not show a significant correlation with GBM incidence (P > 0.05).

CONCLUSION

Findings of the present study provide evidence that the rs1957106 SNP in NF-κBIA is found more in GBM patients, but it was not statistically significant. As there are conflicting studies showing significant higher rate of this SNP in GBM, further study is suggested.

Oxidative stress: therapeutic approaches for cervical cancer treatment

Oxidative stress results from an imbalance between the generation and elimination of oxidant species. This condition may result in DNA, RNA and protein damage, leading to the accumulation of genetic alterations that can favor malignant transformation. Persistent infection with high-risk human papillomavirus types is associated with inflammatory responses and reactive oxygen species production. In this context, oxidative stress, chronic inflammation and high-risk human papillomavirus can act in a synergistic manner. To counteract the harmful effects of oxidant species, protective molecules, known as antioxidant defenses, are produced by cells to maintain redox homeostasis. In recent years, the use of natural antioxidants as therapeutic strategies for cancer treatment has attracted the attention of the scientific community. This review discusses specific molecules and mechanisms that can act against or together with oxidative stress, presenting alternatives for cervical cancer prevention and treatment.

Deepwater Horizon oil alone and in conjunction with Vibrio anguillarum exposure modulates immune response and growth in red snapper (Lutjanus campechanus)

This study examined the impacts of Macondo oil from the Deepwater Horizon oil spill, both alone and in conjunction with exposure to the known fish pathogen Vibrio anguillarum, on the expression of five immune-related gene transcripts of red snapper (il8, il10, tnfa, il1b, and igm). In order to elucidate this impact, six different test conditions were used: one Control group (No oil/No pathogen), one Low oil/No pathogen group (tPAH50 = 0.563 μg/L), one High oil/No pathogen group (tPAH50 = 17.084 μg/L, one No oil/Pathogen group, one Low oil/Pathogen group (tPAH50 = 0.736 μg/L), and one High oil/Pathogen group (tPAH50 = 15.799 μg/L). Fish were exposed to their respective oil concentrations for one week. On day 7 of the experiment, all fish were placed into new tanks (with or without V. anguillarum) for one hour. At three time points (day 8, day 10, and day 17), fish organs were harvested and placed into RNAlater, and qPCR was run for examination of the above specific immune genes as well as cyp1a1. Our results suggest that cyp1a1 transcripts were upregulated in oil-exposed groups throughout the experiment, confirming oil exposure, and that all five immune gene transcripts were upregulated on day 8, but were generally downregulated or showed no differences from controls on days 10 and 17. Finally, both oil and pathogen exposure had impacts on growth.

Reconstitution of Mammalian Enzymatic Deacylation Reactions in Live Bacteria Using Native Acylated Substrates

Lysine deacetylases (KDACs) are enzymes that catalyze the hydrolysis of acyl groups from acyl-lysine residues. The recent identification of thousands of putative acylation sites, including specific acetylation sites, created an urgent need for biochemical methodologies aimed at better characterizing KDAC-substrate specificity and evaluating KDACs activity. To address this need, we utilized genetic code expansion technology to coexpress site-specifically acylated substrates with mammalian KDACs, and study substrate recognition and deacylase activity in live Escherichia coli. In this system the bacterial cell serves as a “biological test tube” in which the incubation of a single mammalian KDAC and a potential peptide or full-length acylated substrate transpires. We report novel deacetylation activities of Zn²⁺-dependent deacetylases and sirtuins in bacteria. We also measure the deacylation of propionyl-, butyryl-, and crotonyl-lysine, as well as novel deacetylation of Lys310-acetylated RelA by SIRT3, SIRT5, SIRT6, and HDAC8. This study highlights the importance of native interactions to KDAC-substrate recognition and deacylase activity.

Exploring major signaling cascades in melanomagenesis: a rationale route for targetted skin cancer therapy

Although most melanoma cases may be treated by surgical intervention upon early diagnosis, a significant portion of patients can still be refractory, presenting low survival rates within 5 years after the discovery of the illness. As a hallmark, melanomas are highly prone to evolve into metastatic sites. Moreover, melanoma tumors are highly resistant to most available drug therapies and their incidence have increased over the years, therefore leading to public health concerns about the development of novel therapies. Therefore, researches are getting deeper in unveiling the mechanisms by which melanoma initiation can be triggered and sustained. In this context, important progress has been achieved regarding the roles and the impact of cellular signaling pathways in melanoma. This knowledge has provided tools for the development of therapies based on the intervention of signal(s) promoted by these cascades. In this review, we summarize the importance of major signaling pathways (mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)-Akt, Wnt, nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB), Janus kinase (JAK)-signal transducer and activator of transcription (STAT), transforming growth factor β (TGF-β) and Notch) in skin homeostasis and melanoma progression. Available and developing melanoma therapies interfering with these signaling cascades are further discussed.

Paeonia lactiflora Pall. regulates the NF-κB-NLRP3 inflammasome pathway to alleviate cholestasis in rats

OBJECTIVES

Cholestasis is a critical risk factor for severe hepatic disease or cirrhosis. The anti-inflammatory effect of Paeonia lactiflora Pall. (PLP), named Chishao in traditional Chinese medicine (TCM), on alpha-naphthylisothiocyanate (ANIT)-induced cholestasis model was tried to be elucidated in this research.

METHODS

Therapeutic effect indices on hepatic function, including ALT, AST, TBIL, DBIL, ALP, TBA and γ-GT, were measured. To further investigate the protective mechanism of PLP, the mRNA and protein expression levels of NF-κB-NLRP3 inflammasome pathway were detected.

RESULTS

Our results showed that compared with the model group, PLP could significantly reduce the increased serum indices such as ALT, AST, TBIL, DBIL, ALP, TBA and γ-GT induced by ANIT in a dose-dependent way. Moreover, we found that PLP downregulated the mRNA expression levels including IKK, p65, NLRP3, caspase-1 and IL-1β, especially at the large dose. Furthermore, PLP also significantly inhibited NF-κB-NLRP3 inflammasome pathway by decreasing the protein levels of p65, p-p65, p-IKK, NLRP3, caspase-1 and IL-1β.

CONCLUSIONS

The results indicated that PLP could ameliorate ANIT-induced cholestasis in rats and the anti-inflammatory effect of PLP might be related to regulating NF-κB-NLRP3 inflammasome pathway. This study will provide scientific evidence for PLP as a potential drug candidate for cholestasis.

Regulatory role of IKKɑ in myocardial ischemia/reperfusion injury by the determination of M1 versus M2 polarization of macrophages

The IκB kinase (IKK) complex plays a well-documented role in cancer and immune system. This function has been widely attributed to its role as the master regulator of the NF-κB family. Particularly, IKKɑ, a member of IKK complex, is reported to have various regulating effects in inflammatory and malignant diseases. However, its role as well as its mechanism of function in macrophages following myocardial ischemia and reperfusion (I/R) injury remains unexplored. In vivo, sham or I/R operations were performed on macrophage-specific IKKɑ knockout (mIKKɑ^-/-) mice and their IKKɑ^flox/flox littermates. We ligated the left anterior descending (LAD) coronary artery of I/R groups simulating ischemia for 30 min, followed by a reperfusion period of 3 days and 7 days, respectively. The hearts of mIKKɑ^-/- mice exhibited significantly increased inflammation and macrophage aggregation as compared to their IKKɑ^flox/flox littermates. Moreover, in the mIKKɑ^-/- group subjected to I/R macrophages had a tendency to polarize to M1 phenotype. In vitro, we stimulated RAW264.7 cells with Lipopolysaccharides (LPS) after infection by the lentivirus, either knocking-down or overexpressing IKKɑ. We discovered that a deficiency of IKKɑ in RAW264.7 caused increased expression of pro-inflammatory markers compared to normal RAW264.7 after LPS stimulation. Inversely, pro-inflammatory factors were inhibited with IKKɑ overexpression. Mechanistically, IKKɑ directly combined with RelB to regulate macrophage polarization. Furthermore, IKKɑ regulated MEK1/2-ERK1/2 and downstream p65 signaling cascades after LPS stimulation. Overall, our data reveals that IKKɑ is a novel mediator protecting against the development of myocardial I/R injury via negative regulation of macrophage polarization to M1 phenotype. Thus, IKKɑ may serve as a valuable therapeutic target for the treatment of myocardial I/R injury.

The Role of the Nuclear Factor κB Pathway in the Cellular Response to Low and High Linear Energy Transfer Radiation

Astronauts are exposed to considerable doses of space radiation during long-term space missions. As complete shielding of the highly energetic particles is impracticable, the cellular response to space-relevant radiation qualities has to be understood in order to develop countermeasures and to reduce radiation risk uncertainties. The transcription factor Nuclear Factor κB (NF-κB) plays a fundamental role in the immune response and in the pathogenesis of many diseases. We have previously shown that heavy ions with a linear energy transfer (LET) of 100–300 keV/µm have a nine times higher potential to activate NF-κB compared to low-LET X-rays. Here, chemical inhibitor studies using human embryonic kidney cells (HEK) showed that the DNA damage sensor Ataxia telangiectasia mutated (ATM) and the proteasome were essential for NF-κB activation in response to X-rays and heavy ions. NF-κB’s role in cellular radiation response was determined by stable knock-down of the NF-κB subunit RelA. Transfection of a RelA short-hairpin RNA plasmid resulted in higher sensitivity towards X-rays, but not towards heavy ions. Reverse Transcriptase real-time quantitative PCR (RT-qPCR) showed that after exposure to X-rays and heavy ions, NF-κB predominantly upregulates genes involved in intercellular communication processes. This process is strictly NF-κB dependent as the response is completely absent in RelA knock-down cells. NF-κB’s role in the cellular radiation response depends on the radiation quality.

Apoptotic and Anti-Inflammatory Effects of Eupatorium japonicum Thunb. in Rheumatoid Arthritis Fibroblast-Like Synoviocytes

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease characterized by synovitis, hyperplasia, and the destruction of bone and cartilage. A variety of immunosuppressive biological agents have been developed because the pathogenesis of RA is related predominantly to the inflammatory response. However, rheumatoid arthritis fibroblast-like synovial cells (RAFLS), which are known to play an important role in RA progression, exhibit resistance to immunosuppressants through cancer-like properties. In this study, we identified a novel therapeutic compound for RA, which reduced inflammation and the abnormal proliferation of RAFLS in natural product library made from Korean native plants. Eupatorium japonicum Thunb. (EJT) extract, a component of the natural product library, most effectively reduced viability through the induction of ROS-mediated apoptosis in a dose-dependent manner. In addition, the increased ROS induced the expression of ATF4 and CHOP, key players in ER stress-mediated apoptosis. Interestingly, EJT extract treatment dose-dependently reduced the expression of IL-1β and the transcription of MMP-9, which were induced by TNF-α treatment, through the inhibition of NF-κB and p38 activation. Collectively, we found that EJT extract exerted apoptotic effects through increases in ROS production and CHOP expression and exerted anti-inflammatory effects through the suppression of NF-κB activation, IL-1β expression, and MMP-9 transcription.

1,10-Secoguaianolides from Artemisia austro-yunnanensis and Their Anti-Inflammatory Effects

Seven 1,10-secoguaianolides 1⁻7, including a new one (compound 1), were isolated from Artemisia austro-yunnanensis and identified by HRESIMS and other spectroscopic methods. Their anti-inflammatory effects were evaluated by the model of LPS-induced RAW264.7 cells in vitro. Bioassay results showed that six of them (1⁻4, 6 and 7), with the exception of 5, produce some cytotoxicity on RAW264.7 cells at its high dosage, can significantly decrease the release of NO, TNF-α, IL-1β, IL-6 and PGE2 in a dose dependent manner, and down-regulate the expression of proteins iNOS and COX-2. The mechanism study indicated they regulated the NF-κB dependent transcriptional activity through decreasing the phosphorylation of NF-κB. Further, the relationship between their structures and cytokines to anti-inflammatory were studied by PCA and discussed.

Mechanisms for butyrate to inhibit ulcerative colitis

Ulcerative colitis (UC) is a kind of inflammatory bowel disease that damages health seriously, and it is reported that butyrate could be used to treat UC. The underlying mechanism is that butyrate can activate G protein-coupled receptors to influence the downstream signaling pathways, thereby inhibiting the expression of cytokines and the differentiation and migration of immune cells. Besides, butyrate can activate peroxisome proliferator-activated receptor gamma, thus decreasing cell permeability and protecting the integrity of the intestinal mucosa. Butyrate can also inhibit the nuclear factor-kappa B signaling pathway, inhibiting the expression of cytokines, accelerating the apoptosis of T cells, and promoting the secretion of human defense peptides. Based on the recent research, we review the underlying mechanisms by which butyrate relieves UC to provide evidence for the clinical application of butyrate.

TSPAN15 interacts with BTRC to promote oesophageal squamous cell carcinoma metastasis via activating NF-κB signaling

Beta-transducin repeat containing E3 ubiquitin protein ligase (BTRC) is crucial for the degradation of IκBα. Our previous transcriptome sequencing analysis revealed that tetraspanin 15 (TSPAN15) was significantly upregulated in clinical oesophageal squamous cell carcinoma (OSCC) tissues. Here, we show that high TSPAN15 expression in OSCC tissues is significantly associated with lymph node and distant metastasis, advanced clinical stage, and poor prognosis. Elevated TSPAN15 expression is, in part, caused by the reduction of miR-339-5p. Functional studies demonstrate that TSPAN15 promotes metastatic capabilities of OSCC cells. We further show that TSPAN15 specifically interacts with BTRC to promote the ubiquitination and proteasomal degradation of p-IκBα, and thereby triggers NF-κB nuclear translocation and subsequent activation of transcription of several metastasis-related genes, including ICAM1, VCAM1, uPA, MMP9, TNFα, and CCL2. Collectively, our findings indicate that TSPAN15 may serve as a new biomarker and/or provide a novel therapeutic target to OSCC patients.

BTRC can activate NF-κB signaling through the ubiquitination and degradation of IκB-α. Here the authors show that TSPAN15 promotes metastasis of oesophageal squamous cell cancer by enhancing BTRC induced degradation of IκB-α and subsequent activation of NF-κB.

The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide dampens lipopolysaccharide-induced transcriptomic changes in macrophages

OBJECTIVE

M1-like inflammatory phenotype of macrophages plays a critical role in tissue damage in chronic inflammatory diseases. Previously, we found that the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) dampens lipopolysaccharide (LPS)-triggered inflammatory priming of RAW 264.7 cells. Herein, we tested whether DMPO by itself can induce changes in macrophage transcriptome, and that these effects may prevent LPS-induced activation of macrophages.

MATERIALS AND METHODS

To test our hypothesis, we performed a transcriptomic and bioinformatics analysis in RAW 264.7 cells incubated with or without LPS, in the presence or in the absence of DMPO.

RESULTS

Functional data analysis showed 79 differentially expressed genes (DEGs) when comparing DMPO vs Control. We used DAVID databases for identifying enriched gene ontology terms and Ingenuity Pathway Analysis for functional analysis. Our data showed that DMPO vs Control comparison of DEGs is related to downregulation immune-system processes among others. Functional analysis indicated that interferon-response factor 7 and toll-like receptor were related (predicted inhibitions) to the observed transcriptomic effects of DMPO. Functional data analyses of the DMPO + LPS vs LPS DEGs were consistent with DMPO-dampening LPS-induced inflammatory transcriptomic profile in RAW 264.7. These changes were confirmed using Nanostring technology.

CONCLUSIONS

Taking together our data, surprisingly, indicate that DMPO by itself affects gene expression related to regulation of immune system and that DMPO dampens LPS-triggered MyD88- and TRIF-dependent signaling pathways. Our research provides critical data for further studies on the possible use of DMPO as a structural platform for the design of novel mechanism-based anti-inflammatory drugs.

Participation of the IKK-α/β complex in the inhibition of the TNF-α/NF-κB pathway by glycine: Possible involvement of a membrane receptor specific to adipocytes

Glycine modulates inflammatory processes mediated by macrophages and adipocytes through decreasing the secretion of TNF-α, IL-6, and leptin, while increasing adiponectin. These effects have been associated with the inactivation of NF-κB in response to TNF-α, across an increase of its inhibitor IκB-α in adipocytes. However, glycine upstream mainly influences the IκB kinase (IKK) complex, a multi-protein kinase complex considered a critical point in regulation of the NF-κB pathway; whether that is responsible for the TNF-α-induced phosphorylation of IkB has not been explored. Additionally, although previous studies have described glycine interactions with specific receptors (GlyR) in different immune system cell types, it is currently unknown whether adipocytes present GlyR. In this research, participation of the IKK-α/β complex in the inhibition of the TNF-α/NF-κB pathway by glycine was evaluated and associated with the synthesis and secretion of inflammatory cytokines in 3T3-L1 adipocytes. Furthermore, we also explored GlyR expression, its localization on the plasmatic membrane, intracellular calcium concentrations [Ca²⁺]_i and strychnine antagonist action over the GlyR in these cells. Glycine decreased the IKK-α/β complex and the phosphorylation of NF-κB, diminishing the expression and secretion of IL-6 and TNF-α, but increasing that of adiponectin. GlyR expression and its fluorescence in the plasma membrane were increased in the presence of glycine. In addition, glycine decreased [Ca²⁺]_i; whereas strychnine + glycine treatment inhibited the activation of NF-κB observed with glycine. In conclusion, the reduction of TNF-α and IL-6 and suppression of the TNF-α/NF-κB pathway by glycine may be explained in part by inhibition of the IKK-α/β complex, with a possible participation of GlyR in 3T3-L1 adipocytes.

Emerging roles of endoplasmic reticulum-resident selenoproteins in the regulation of cellular stress responses and the implications for metabolic disease

Chronic metabolic stress leads to cellular dysfunction, characterized by excessive reactive oxygen species, endoplasmic reticulum (ER) stress and inflammation, which has been implicated in the pathogenesis of obesity, type 2 diabetes and cardiovascular disease. The ER is gaining recognition as a key organelle in integrating cellular stress responses. ER homeostasis is tightly regulated by a complex antioxidant system, which includes the seven ER-resident selenoproteins - 15 kDa selenoprotein, type 2 iodothyronine deiodinase and selenoproteins S, N, K, M and T. Here, the findings from biochemical, cell-based and mouse studies investigating the function of ER-resident selenoproteins are reviewed. Human experimental and genetic studies are drawn upon to highlight the relevance of these selenoproteins to the pathogenesis of metabolic disease. ER-resident selenoproteins have discrete roles in the regulation of oxidative, ER and inflammatory stress responses, as well as intracellular calcium homeostasis. To date, only two of these ER-resident selenoproteins, selenoproteins S and N have been implicated in human disease. Nonetheless, the potential of all seven ER-resident selenoproteins to ameliorate metabolic dysfunction warrants further investigation.

Supplementation with Resveratrol and Curcumin Does Not Affect the Inflammatory Response to a High-Fat Meal in Older Adults with Abdominal Obesity: A Randomized, Placebo-Controlled Crossover Trial

Background

High-fat meals induce postprandial inflammation. Resveratrol is a polyphenol known to prevent comorbidities associated with cardiovascular disease and exerts an anti-inflammatory action. There is also an increasing body of evidence supporting the role of curcumin, a polyphenol from the curcuminoid family, as a modulator of proinflammatory processes.

Objective

The objectives of this study were to investigate the following: 1) the bioavailability of resveratrol consumed in combination with curcumin after consumption of a high-fat meal; and 2) the acute combined effects of this combination on the postprandial inflammatory response of subjects with abdominal obesity.

Methods

In a double blind, crossover, randomized, placebo-controlled study, 11 men and 11 postmenopausal women [mean ± SD age: 62 ± 5 y; mean ± SD body mass index (in kg/m2): 29 ± 3] underwent a 6-h oral fat tolerance test on 2 occasions separated by 1-2 wk: once after consumption of a dietary supplement (200 mg resveratrol and 100 mg curcumin, Res/Cur) and once after consumption of a placebo (cellulose). Plasma concentrations of total resveratrol and its major metabolites as well as inflammatory markers, adhesion molecules, and whole blood NFκB1 and PPARA gene expression were measured during both fat tolerance tests.

Results

Kinetics of resveratrol and identified metabolites revealed rapid absorption patterns but also relatively limited bioavailability based on free resveratrol concentrations. Supplementation with Res/Cur did not modify postprandial variations in circulating inflammatory markers (C-reactive protein, IL-6, IL-8, monocyte chemoattractant protein-1) and adhesion molecules [soluble E-selectin, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1] compared to placebo (PTreatment×Time > 0.05). However, Res/Cur significantly decreased the cumulative postprandial response of sVCAM-1, compared to placebo (incremental area under the curve -4643%, P = 0.01). Postprandial variations of whole-blood PPARA and NFKB1 gene expression were not different between Res/Cur and placebo treatments.

Conclusions

Acute supplementation with Res/Cur has no impact on the postprandial inflammation response to a high-fat meal in abdominally obese older adults. Further studies are warranted to examine how resveratrol and curcumin may alter the vascular response to a high-fat meal. This trial was registered at clinicaltrials.gov as NCT01964846.

Melanocortin overexpression limits diet-induced inflammation and atherosclerosis in LDLR-/- mice

Atherosclerosis is a chronic inflammatory disease of the arteries. The disease is initiated by endothelial dysfunction that allows the transport of leukocytes and low-density lipoprotein into the vessel wall forming atherosclerotic plaques. The melanocortin system is an endogenous peptide system that regulates, for example, energy homeostasis and cardiovascular function. Melanocortin treatment with endogenous or synthetic melanocortin peptides reduces body weight, protects the endothelium and alleviates vascular inflammation, but the long-term effects of melanocortin system activation on atheroprogression remain largely unknown. In this study, we evaluated the effects of transgenic melanocortin overexpression in a mouse model of atherosclerosis. Low-density lipoprotein receptor-deficient mice overexpressing alpha- and gamma₃-MSH (MSH-OE) and their wild-type littermates were fed either a regular chow or Western-style diet for 16 weeks. During this time, their metabolic parameters were monitored. The aortae were collected for functional analysis, and the plaques in the aortic root and arch were characterised by histological and immunohistochemical stainings. The aortic expression of inflammatory mediators was determined by quantitative PCR. We found that transgenic MSH-OE improved glucose tolerance and limited atherosclerotic plaque formation particularly in Western diet-fed mice. In terms of aortic vasoreactivity, MSH-OE blunted alpha₁-adrenoceptor-mediated vasoconstriction and enhanced relaxation response to acetylcholine, indicating improved endothelial function. In addition, MSH-OE markedly attenuated Western diet-induced upregulation of proinflammatory cytokines (Ccl2, Ccl5 and Il6) that contribute to the pathogenesis of atherosclerosis. These results show that the activation of the melanocortin system improves glucose homeostasis and limits diet-induced vascular inflammation and atherosclerotic plaque formation.

Ginsenoside Rg3 suppresses mast cell-mediated allergic inflammation via mitogen-activated protein kinase signaling pathway

Background

Ginsenoside Rg3 (G-Rg3) is the major bioactive ingredient of Panax ginseng and has many pharmacological effects, including antiadipogenic, antiviral, and anticancer effects. However, the effect of G-Rg3 on mast cell–mediated allergic inflammation has not been investigated.

Method

The antiallergic effects of G-Rg3 on allergic inflammation were evaluated using the human and rat mast cell lines HMC-1 and RBL-2H3. Antiallergic effects of G-Rg3 were detected by measuring cyclic adenosine monophosphate (cAMP), detecting calcium influx, and using real-time reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and in vivo experiments.

Results

G-Rg3 decreased histamine release from activated mast cells by enhancing cAMP levels and calcium influx. Proinflammatory cytokine production was suppressed by G-Rg3 treatment via regulation of the mitogen-activated protein kinases/nuclear factor-kappa B and receptor-interacting protein kinase 2 (RIP2)/caspase-1 signaling pathway in mast cells. Moreover, G-Rg3 protected mice against the IgE-mediated passive cutaneous anaphylaxis reaction and compound 48/80-induced anaphylactic shock.

Conclusion

G-Rg3 may serve as an alternative therapeutic agent for improving allergic inflammatory disorders.

Macrophage activation marker sCD163 correlates with accelerated lipolysis following LPS exposure: a human-randomised clinical trial

BACKGROUND

Macrophage activation determined by levels of soluble sCD163 is associated with obesity, insulin resistance, diabetes mellitus type 2 (DM2) and non-alcoholic fatty liver disease (NAFLD). This suggests that macrophage activation is involved in the pathogenesis of conditions is characterised by adaptions in the lipid metabolism. Since sCD163 is shed to serum by inflammatory signals including lipopolysaccharides (LPS, endotoxin), we investigated sCD163 and correlations with lipid metabolism following LPS exposure.

METHODS

Eight healthy male subjects were investigated on two separate occasions: (i) following an LPS exposure and (ii) following saline exposure. Each study day consisted of a four-hour non-insulin-stimulated period followed by a two-hour hyperinsulinemic euglycemic clamp period. A ³H-palmitate tracer was used to calculate the rate of appearance (Ra_palmitate). Blood samples were consecutively obtained throughout each study day. Abdominal subcutaneous adipose tissue was obtained for western blotting.

RESULTS

We observed a significant two-fold increase in plasma sCD163 levels following LPS exposure (P < 0.001), and sCD163 concentrations correlated positively with the plasma concentration of free fatty acids, Ra_palmitate, lipid oxidation rates and phosphorylation of the hormone-sensitive lipase at serine 660 in adipose tissue (P < 0.05, all). Furthermore, sCD163 concentrations correlated positively with plasma concentrations of cortisol, glucagon, tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10 (P < 0.05, all).

CONCLUSION

We observed a strong correlation between sCD163 and stimulation of lipolysis and fat oxidation following LPS exposure. These findings support preexisting theory that inflammation and macrophage activation play a significant role in lipid metabolic adaptions under conditions such as obesity, DM2 and NAFLD.

Structure and Function of Viral Deubiquitinating Enzymes

Post-translational modification of cellular proteins by ubiquitin regulates numerous cellular processes, including innate and adaptive immune responses. Ubiquitin-mediated control over these processes can be reversed by cellular deubiquitinating enzymes (DUBs), which remove ubiquitin from cellular targets and depolymerize polyubiquitin chains. The importance of protein ubiquitination to host immunity has been underscored by the discovery of viruses that encode proteases with deubiquitinating activity, many of which have been demonstrated to actively corrupt cellular ubiquitin-dependent processes to suppress innate antiviral responses and promote viral replication. DUBs have now been identified in diverse viral lineages, and their characterization is providing valuable insights into virus biology and the role of the ubiquitin system in host antiviral mechanisms. Here, we provide an overview of the structural biology of these fascinating viral enzymes and their role innate immune evasion and viral replication.

Agonists for G-protein-coupled receptor 84 (GPR84) alter cellular morphology and motility but do not induce pro-inflammatory responses in microglia

Background

Several G-protein-coupled receptors (GPCRs) have been shown to be important signaling mediators between neurons and glia. In our previous screening for identification of nerve injury-associated GPCRs, G-protein-coupled receptor 84 (GPR84) mRNA showed the highest up-regulation by microglia after nerve injury. GPR84 is a pro-inflammatory receptor of macrophages in a neuropathic pain mouse model, yet its function in resident microglia in the central nervous system is poorly understood.

Methods

We used endogenous, natural, and surrogate agonists for GPR84 (capric acid, embelin, and 6-OAU, respectively) and examined their effect on mouse primary cultured microglia in vitro.

Results

6-n-Octylaminouracil (6-OAU), embelin, and capric acid rapidly induced membrane ruffling and motility in cultured microglia obtained from C57BL/6 mice, although these agonists failed to promote microglial pro-inflammatory cytokine expression. Concomitantly, 6-OAU suppressed forskolin-induced increase of cAMP in cultured microglia. Pertussis toxin, an inhibitor of Gi-coupled signaling, completely suppressed 6-OAU-induced microglial membrane ruffling and motility. In contrast, no 6-OAU-induced microglial membrane ruffling and motility was observed in microglia from DBA/2 mice, a mouse strain that does not express functional GPR84 protein due to endogenous nonsense mutation of the GPR84 gene.

Conclusions

GPR84 mediated signaling causes microglial motility and membrane ruffling but does not promote pro-inflammatory responses. As GPR84 is a known receptor for medium-chain fatty acids, those released from damaged brain cells may be involved in the enhancement of microglial motility through GPR84 after neuronal injury.

The sneaking ligand approach for cell type-specific modulation of intracellular signalling pathways

Small molecules interfering with intracellular signalling pathways are used in the treatment of multiple diseases including RA. However, small molecules usually affect signalling in most cell types, not only in those which need to be targeted. This general inhibition of signalling pathways causes often adverse effects, which could be avoided by cell type-specific inhibitors. For cell-type specific modulation of signal transduction, we developed the sneaking ligand fusion proteins (SLFPs). SLFPs contain three domains: (1) the binding domain mediating cell type-specific targeting and endocytosis; (2) the endosomal release sequence releasing the effector domain into the cytoplasm; (3) the effector domain modulating signalling. Using our SLFP NF-kappaB inhibitor termed SLC1 we demonstrated that cell-type-specific modulation of intracellular signalling pathways is feasible, that endothelial NF-kappaB activation is critical for arthritis and peritonitis and that SLFPs help to identify disease-relevant pathways in defined cell types. Hence, SLFPs may improve risk-benefit ratios of therapeutic interventions.

Fentanyl Ameliorates Severe Acute Pancreatitis-Induced Myocardial Injury in Rats by Regulating NF-κB Signaling Pathway

Background

Acute pancreatitis (AP) is a sudden inflammation of the pancreas. It results in multiple, severe complications, and 15–20% of patients develop severe acute pancreatitis (SAP) with mortality as high as 30%. Consequently, it is imperative to develop an effective therapy for SAP.

Material/Methods

We used 30 adult male Sprague Dawley (SD) rats. Rats were randomly divided into 3 groups – sham, SAP, and fentanyl+SAP – with 10 rats in each group. An automatic biochemical analyzer was used to analyze the concentration of creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH). Terminal-deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) assay was applied to assess the cell apoptosis rate. Pathological changes in pancreas/heart were detected with hematoxylin and eosin (HE) staining. Western immunoblot assay was used to analyze protein levels of interleukin (IL)-1β, IL-6, and IκB.

Results

Fentanyl pre-treatment inhibits SAP-induced elevation of CK-MB/LDH concentrations in serum. Compared with the sham group, SAP generates a higher brown/yellow staining rate, which is abated by fentanyl. In the pancreas, SAP generated more serious interstitial edema/hemorrhage and fat necrosis than in the sham group, which are attenuated by fentanyl. Likewise, compared to the sham group, SAP generates swelled/disordered myocardial fibers and congested blood vessels in myocardium, which are ameliorated by fentanyl. In the sham group, there was little IL-1β/IL-6, and fentanyl significantly inhibited SAP-induced up-regulation of IL-1β/IL-6 levels. Compared with the sham group, SAP significantly reduced IκB level, which was rescued by fentanyl.

Conclusions

Fentanyl effectively alleviates SAP-induced pancreas and heart injuries through regulating the nuclear factor-κB (NF-κB) signaling pathway.

The Phenolic Fraction of Mentha haplocalyx and Its Constituent Linarin Ameliorate Inflammatory Response through Inactivation of NF-κB and MAPKs in Lipopolysaccharide-Induced RAW264.7 Cells

Mentha haplocalyx has been widely used for its flavoring and medicinal properties and as a traditional Chinese medicine with its anti-inflammation properties. The present study was designed to investigate the anti-inflammatory effects and potential molecular mechanisms of the phenolic fraction of M. haplocalyx (MHP) and its constituent linarin in lipopolysaccharide (LPS)-induced RAW264.7 cells. The high-performance liquid chromatography coupled with linear ion trap-orbitrap mass spectrometry (HPLC-LTQ-Orbitrap MS) was used to analyze the chemical composition of MHP. Using the enzyme-linked immunosorbent assay (ELISA) and quantitative realtime polymerase chain reaction (qRT-PCR), the expression of pro-inflammatory meditators and cytokines was measured at the transcriptional and translational levels. Western blot analysis was used to further investigate changes in the nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and Akt signaling pathways. Fourteen phenolic constituents were identified from MHP based on the data of the mass spectrometry (MS)/MS analysis. MHP and linarin decreased the production of NO, tumor necrosis factor-α (TNF-α), interlenkin-1β (IL-1β), and IL-6. The messenger ribonucleic acid (mRNA) expression levels of inducible NO synthase (iNOS), TNF-α, IL-1β, and IL-6 were also suppressed by MHP and linarin. Further investigation showed that MHP and linarin down-regulated LPS-induced phosphorylation content of NF-κB p65, inhibitor kappa B α (IκBα), extracellular signal-regulated kinase (ERK), c-Jun NH₂-terminal kinase (JNK), and p38. However, MHP and linarin showed no inhibitory effect on the phosphorylated Akt. These results suggested that MHP and linarin exerted a potent inhibitory effect on pro-inflammatory meditator and cytokines production via the inactivation of NF-κB and MAPKs, and they may serve as potential modulatory agents for the prevention and treatment of inflammatory diseases.

Ferulic acid suppresses expression of tryptophan metabolic key enzyme indoleamine 2, 3-dioxygenase via NFκB and p38 MAPK in lipopolysaccharide-stimulated microglial cells

Ferulic acid (FA) is a phenol compound found in plants that has anti-inflammatory properties. Indoleamine 2, 3-dioxygenase (IDO) is a tryptophan catabolic enzyme induced in immune cells, including glial cells, during inflammation. Enhanced IDO expression leads to reduced tryptophan levels and increased levels of toxic metabolites, including quinolinic acid. Therefore, inhibition of IDO expression may be effective in suppressing progression of neurodegenerative diseases. In this study, we examined the effect of FA in microglial cells on IDO expression levels and related inflammatory signal molecules. FA suppressed LPS-induced IDO mRNA expression and also suppressed nuclear translocation of NF-κB and phosphorylation of p38 MAPK. However, FA did not affect the production of LPS-induced inflammatory mediators and phosphorylation of JNK. Our results indicate that FA suppresses LPS-induced IDO mRNA expression, which may be mediated by inhibition of the NF-κB and p38 MAPK pathways in microglial cells.

Capsular Polysaccharide is a Main Component of Mycoplasma ovipneumoniae in the Pathogen-Induced Toll-Like Receptor-Mediated Inflammatory Responses in Sheep Airway Epithelial Cells

Mycoplasma ovipneumoniae (M. ovipneumoniae) is characterized as an etiological agent of primary atypical pneumonia that specifically infects sheep and goat. In an attempt to better understand the pathogen-host interaction between the invading M. ovipneumoniae and airway epithelial cells, we investigated the host inflammatory responses against capsular polysaccharide (designated as CPS) of M. ovipneumoniae using sheep bronchial epithelial cells cultured in an air-liquid interface (ALI) model. Results showed that CPS derived from M. ovipneumoniae could activate toll-like receptor- (TLR-) mediated inflammatory responses, along with an elevated expression of nuclear factor kappa B (NF-κB), activator protein-1 (AP-1), and interferon regulatory factor 3 (IRF3) as well as various inflammatory-associated mediators, representatively including proinflammatory cytokines, such as IL1β, TNFα, and IL8, and anti-inflammatory cytokines such as IL10 and TGFβ of TLR signaling cascade. Mechanistically, the CPS-induced inflammation was TLR initiated and was mediated by activations of both MyD88-dependent and MyD88-independent signaling pathways. Of importance, a blockage of CPS with specific antibody led a significant reduction of M. ovipneumoniae-induced inflammatory responses in sheep bronchial epithelial cells. These results suggested that CPS is a key virulent component of M. ovipneumoniae, which may play a crucial role in the inflammatory response induced by M. ovipneumoniae infections.

Catechins and Their Therapeutic Benefits to Inflammatory Bowel Disease

Catechins are natural polyphenolic phytochemicals that exist in food and medicinal plants, such as tea, legume and rubiaceae. An increasing number of studies have associated the intake of catechins-rich foods with the prevention and treatment of chronic diseases in humans, such as inflammatory bowel disease (IBD). Some studies have demonstrated that catechins could significantly inhibit the excessive oxidative stress through direct or indirect antioxidant effects and promote the activation of the antioxidative substances such as glutathione peroxidases (GPO) and glutathione (GSH), reducing the oxidative damages to the colon. In addition, catechins can also regulate the infiltration and proliferation of immune related-cells, such as neutrophils, colonic epithelial cells, macrophages, and T lymphocytes, helping reduce the inflammatory relations and provide benefits to IBD. Perhaps catechins can further inhibit the deterioration of intestinal lesions through regulating the cell gap junctions. Furthermore, catechins can exert their significant anti-inflammatory properties by regulating the activation or deactivation of inflammation-related oxidative stress-related cell signaling pathways, such as nuclear factor-kappa B (NF-κB), mitogen activated protein kinases (MAPKs), transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2), signal transducer and the activator of transcription 1/3 (STAT1/3) pathways. Finally, catechins can also stabilize the structure of the gastrointestinal micro-ecological environment via promoting the proliferation of beneficial intestinal bacteria and regulating the balance of intestinal flora, so as to relieve the IBD. Furthermore, catechins may regulate the tight junctions (TJ) in the epithelium. This paper elaborates the currently known possible molecular mechanisms of catechins in favor of IBD.

Phospholipid localization implies microglial morphology and function via Cdc42 in vitro

Under a quiescent state, microglia exhibit a ramified shape, rather than the amoeboid-like morphology following injury or inflammation. The manipulation of microglial morphology in vitro has not been very successful, which has impeded the progress of microglial studies. We demonstrate that lysophosphatidylserine (LysoPS), a kind of lysophospholipids, rapidly and substantially alters the morphology of primary cultured microglia to an in vivo-like ramified shape in a receptor independent manner. This mechanism is mediated by Cdc42 activity. LysoPS is incorporated into the plasma membrane and converted to phosphatidylserine (PS) via the Lands' cycle. The accumulated PS on the membrane recruits Cdc42. Both Cdc42 and PS colocalize predominantly in primary and secondary processes, but not in peripheral branches or tips of microglia. Along with the morphological changes LysoPS suppresses inflammatory cytokine production and NF-kB activity. The present study provides a tool to manipulate a microglial phenotype from an amoeboid to a fully ramified in vitro, which certainly contributes to studies exploring microglial physiology and pathology.