Cutting Edge: Novel Role of Lipoxygenases in the Inflammatory Response: Promotion of TNF mRNA Decay by 15-Hydroperoxyeicosatetraenoic Acid in a Monocytic Cell Line

Sterol Derivatives Specifically Increase Anti-Inflammatory Oxylipin Formation in M2-like Macrophages by LXR-Mediated Induction of 15-LOX

The understanding of the role of LXR in the regulation of macrophages during inflammation is emerging. Here, we show that LXR agonist T09 specifically increases 15-LOX abundance in primary human M2 macrophages. In time- and dose-dependent incubations with T09, an increase of 3-fold for ALOX15 and up to 15-fold for 15-LOX-derived oxylipins was observed. In addition, LXR activation has no or moderate effects on the abundance of macrophage marker proteins such as TLR2, TLR4, PPARγ, and IL-1RII, as well as surface markers (CD14, CD86, and CD163). Stimulation of M2-like macrophages with FXR and RXR agonists leads to moderate ALOX15 induction, probably due to side activity on LXR. Finally, desmosterol, 24(S),25-Ep cholesterol and 22(R)-OH cholesterol were identified as potent endogenous LXR ligands leading to an ALOX15 induction. LXR-mediated ALOX15 regulation is a new link between the two lipid mediator classes sterols, and oxylipins, possibly being an important tool in inflammatory regulation through anti-inflammatory oxylipins.

Integrated Network Pharmacology and Metabolomics Analysis to Reveal the Potential Mechanism of Siwu Paste on Aplastic Anemia Induced by Chemotherapy Drugs

Purpose

This study aimed to reveal the multicomponent synergy mechanisms of SWP based on network pharmacology and metabolomics for exploring the relationships of active ingredients, biological targets, and crucial metabolic pathways.

Materials

Network pharmacology, including TRRUST, GO, and KEGG, enrichment was used to discover the active ingredients and potential regulation mechanisms of SWP. LC-MS and multivariate data analysis method were further applied to analyze serum metabolomics profiling for discovering the potential metabolic mechanisms of SWP on AA induced by Cyclophosphamide (CTX) and 1-Acetyl-2-phenylhydrazine (APH).

Results

A total of 27 important bioactive ingredients meeting the ADME (absorption, distribution, metabolism, and excretion) screening criteria from SWP were selected. Interaction networks were constructed and validated based on the 10 associated ingredients with the relevant targets. A total of 125 biomarkers were found by Metabolomics approach, which associated with the development of AA, mainly involved in amino acid metabolism and lipid metabolism. While SWP can reverse the above 12 metabolites changed by AA. Network analysis revealed the synergistic effects of SWP through the 43 crucial pathways, including Sphingolipid signaling pathway, Sphingolipid metabolism, Arginine and proline metabolism, VEGF signaling pathway, Estrogen signaling pathway.

Conclusion

The study suggested that SWP is a useful alternative for the treatment of AA induced by CTX + APH. Its potential mechanisms are to improve hematopoietic microenvironment and promote bone marrow hematopoiesis therapies.

Reprogramming of Metabolism in Kidney Cancer

Metabolic reprogramming is one of the major steps that tumor cells take during cancer progression. This process allows the cells to survive in a nutrient- and oxygen-deprived environment, to become stress tolerant, and to metastasize to different sites. Recent studies have shown that reprogramming happens in stromal cells and involves the cross-talk of the cancer cell/tumor microenvironment. There are similarities between the metabolic reprogramming that occurs in both noncancerous kidney diseases and renal cell carcinoma (RCC), suggesting that such reprogramming is a means by which renal epithelial cells survive injury and repair the tissue, and that RCC cells hijack this system. This article reviews reprogramming of major metabolism pathways in RCC, highlighting similarities and differences from kidney diseases and potential therapeutic strategies against it.

Anti-allergic Hydroxy Fatty Acids from Typhonium blumei Explored through ChemGPS-NP

Increasing prevalence of allergic diseases with an inadequate variety of treatment drives forward search for new alternative drugs. Fatty acids, abundant in nature, are regarded as important bioactive compounds and powerful nutrients playing an important role in lipid homeostasis and inflammation. Phytochemical study on Typhonium blumei Nicolson and Sivadasan (Araceae), a folk anti-cancer and anti-inflammatory medicine, yielded four oxygenated fatty acids, 12R-hydroxyoctadec-9Z,13E-dienoic acid methyl ester (1) and 10R-hydroxyoctadec-8E,12Z-dienoic acid methyl ester (2), 9R-hydroxy-10E-octadecenoic acid methyl ester (3), and 12R^*-hydroxy-10E-octadecenoic acid methyl ester (4). Isolated compounds were identified by spectroscopic methods along with GC-MS analysis. Isolated fatty acids together with a series of saturated, unsaturated and oxygenated fatty acids were evaluated for their anti-inflammatory and anti-allergic activities in vitro. Unsaturated (including docosahexaenoic and eicosapentaenoic acids) as well as hydroxylated unsaturated fatty acids exerted strong anti-inflammatory activity in superoxide anion generation (IC₅₀ 2.14-3.73 μM) and elastase release (IC₅₀ 1.26-4.57 μM) assays. On the other hand, in the anti-allergic assays, the unsaturated fatty acids were inactive, while hydroxylated fatty acids showed promising inhibitory activity in A23187- and antigen-induced degranulation assays (e.g., 9S-hydroxy-10E,12Z-octadecadienoic acid, IC₅₀ 92.4 and 49.7 μM, respectively). According to our results, the presence of a hydroxy group in the long chain did not influence the potent anti-inflammatory activity of free unsaturated acids. Nevertheless, hydroxylation of fatty acids (or their methyl esters) seems to be a key factor for the anti-allergic activity observed in the current study. Moreover, ChemGPS-NP was explored to predict the structure-activity relationship of fatty acids. The anti-allergic fatty acids formed different cluster distant from clinically used drugs. The bioactivity of T. blumei, which is historically utilized in folk medicine, might be related to the content of fatty acids and their metabolites.

Impact of non-surgical periodontal therapy on saliva and serum levels of markers of oxidative stress

OBJECTIVE

The purpose of this study was to determine the effect of non-surgical periodontal treatment on markers of oxidative stress in saliva and serum in patients with chronic periodontitis.

MATERIALS AND METHODS

In total, 25 patients, who were diagnosed with generalized chronic periodontitis (11 females and 14 males), and 26 systemically and periodontally healthy individuals (15 females and 11 males) were included. The plaque index (PI), gingival index (GI), probing pocket depth (PPD), attachment loss (AL), gingival recession (GR), and bleeding on probing (BOP) were recorded at baseline and 6 weeks later. Malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and 4-hydroxy-2-nonenal (4-HNE) were assessed in saliva and serum samples before and after the non-surgical treatment by enzyme-linked immune sorbent assay (ELISA).

RESULTS

In the group with chronic periodontitis, all clinical parameters were significantly higher compared to the control group at baseline (p < 0.001). Periodontal treatment reduced plaque, gingival inflammation, and pocket depth significantly (p < 0.001). At baseline, salivary 8-OHdG was significantly higher in chronic periodontitis (p < 0.001) and reduced significantly subsequent to the periodontal treatment (p < 0.001). Salivary MDA and serum 4-HNE were significantly higher in the patients with periodontitis compared to the control group (p < 0.001). Periodontal treatment did not significantly change the levels of 4-HNE and salivary MDA (p = 0.503, p = 0.093).

CONCLUSIONS

Salivary 8-OHdG and MDA may be associated with local impact of periodontal disease, while 4-HNE may be associated with systemic impact of chronic periodontitis.

CLINICAL RELEVANCE

Clinical intervention in periodontitis may be beneficial for periodontitis patients' systemic oxidative stress control, and using lipidic agents for the use of anti-inflammatory/pro-resolving processes for blocking the actions of arachidonic acid cascade can enable some late therapeutic strategies in order to lead oxidative stress-induced inflammation.

Proteomic analysis of nasal epithelial cells from cystic fibrosis patients

The pathophysiology of cystic fibrosis (CF) lung disease remains incompletely understood. New explanations for the pathogenesis of CF lung disease may be discovered by studying the patterns of protein expression in cultured human nasal epithelial cells (HNEC). To that aim, we compared the level of protein expressions in primary cultures of HNEC from nasal polyps secondary to CF (CFNP, n = 4), primary nasal polyps (NP, n = 8) and control mucosa (CTRL, n = 4) using isobaric tag for relative and absolute quantification (iTRAQ) labeling coupled with liquid chromatography (LC)-MS-MS. The analysis of the data revealed 42 deregulated protein expressions in CFNP compared to NP and CTRL, suggesting that these alterations are related to CF. Overall, AmiGo analysis highlighted six major pathways important for cell functions that seem to be impaired: metabolism, G protein process, inflammation and oxidative stress response, protein folding, proteolysis and structural proteins. Among them, glucose and fatty acid metabolic pathways could be impaired in CF with nine deregulated proteins. Our proteomic study provides a reproducible set of differentially expressed proteins in airway epithelial cells from CF patients and reveals many novel deregulated proteins that could lead to further studies aiming to clarify the involvement of such proteins in CF pathophysiology.

Current and emerging strategies for the treatment and management of systemic lupus erythematosus based on molecular signatures of acute and chronic inflammation

Lupus is a chronic, systemic inflammatory condition in which eicosanoids, cytokines, nitric oxide (NO), a deranged immune system, and genetics play a significant role. Our studies revealed that an imbalance in the pro- and antioxidants and NO and an alteration in the metabolism of essential fatty acids exist in lupus. The current strategy of management includes administration of nonsteroidal anti-inflammatory drugs such as hydroxychloroquine and immunosuppressive drugs such as corticosteroids. Investigational drugs include the following: 1) belimumab, a fully human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, also known as B-cell-activation factor of the TNF family; 2) stem cell transplantation; 3) rituximab, a chimeric monoclonal antibody against CD20, which is primarily found on the surface of B-cells and can therefore destroy B-cells; and 4) IL-27, which has potent anti-inflammatory actions. Our studies showed that a regimen of corticosteroids and cyclophosphamide, and methods designed to enhance endothelial NO synthesis and augment antioxidant defenses, led to induction of long-lasting remission of the disease. These results suggest that methods designed to modulate molecular signatures of the disease process and suppress inflammation could be of significant benefit in lupus. Some of these strategies could be vagal nerve stimulation, glucose-insulin infusion, and administration of lipoxins, resolvins, protectins, and nitrolipids by themselves or their stable synthetic analogs that are known to suppress inflammation and help in the resolution and healing of the inflammation-induced damage. These strategies are likely to be useful not only in lupus but also in other conditions, such as rheumatoid arthritis, scleroderma, ischemia-reperfusion injury to the myocardium, ischemic heart disease, and sepsis.

Omega-3 fatty acids and inflammatory processes

Long chain fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or at least associated with, changes in fatty acid composition of cell membranes. Changes in these compositions can modify membrane fluidity, cell signaling leading to altered gene expression, and the pattern of lipid mediator production. Cell involved in the inflammatory response are typically rich in the n-6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these often have differing properties from those of arachidonic acid-derived eicosanoids. EPA and DHA give rise to newly discovered resolvins which are anti-inflammatory and inflammation resolving. Increased membrane content of EPA and DHA (and decreased arachidonic acid content) results in a changed pattern of production of eicosanoids and resolvins. Changing the fatty acid composition of cells involved in the inflammatory response also affects production of peptide mediators of inflammation (adhesion molecules, cytokines etc.). Thus, the fatty acid composition of cells involved in the inflammatory response influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti-inflammatory effects of marine n-3 PUFAs suggest that they may be useful as therapeutic agents in disorders with an inflammatory component.

Human articular chondrocytes express 15-lipoxygenase-1 and -2: potential role in osteoarthritis

Introduction

15-Lipoxygenases and their metabolites have been shown to exhibit anti-inflammatory and immunomodulatory properties, but little is known regarding their expression and function in chondrocytes. The objective of this study was to evaluate the expression of 15-lipoxygenase-1 and -2 in human articular chondrocytes, and to investigate the effects of their metabolites 13(S)-hydroxy octadecadienoic and 15(S)-hydroxyeicosatetraenoic acids on IL-1β-induced matrix metalloproteinase (MMP)-1 and MMP-13 expression.

Methods

The expression levels of 15-lipoxygenase-1 and -2 were analyzed by reverse transcription PCR and Western blotting in chondrocytes, and by immunohistochemistry in cartilage. Chondrocytes or cartilage explants were stimulated with IL-1β in the absence or presence of 13(S)-hydroxy octadecadienoic and 15(S)-hydroxyeicosatetraenoic acids, and the levels of MMP-1 and MMP-13 protein production and type II collagen cleavage were evaluated using immunoassays. The role of peroxisome proliferator-activated receptor (PPAR)γ was evaluated using transient transfection experiments and the PPARγ antagonist GW9662.

Results

Articular chondrocytes express 15-lipoxygenase-1 and -2 at the mRNA and protein levels. 13(S)-hydroxy octadecadienoic and 15(S)-hydroxyeicosatetraenoic acids dose dependently decreased IL-1β-induced MMP-1 and MMP-13 protein and mRNA expression as well as type II collagen cleavage. The effect on MMP-1 and MMP-13 expression does not require de novo protein synthesis. 13(S)-hydroxy octadecadienoic and 15(S)-hydroxyeicosatetraenoic acids activated endogenous PPARγ, and GW9662 prevented their suppressive effect on MMP-1 and MMP-13 production, suggesting the involvement of PPARγ in these effects.

Conclusions

This study is the first to demonstrate the expression of 15-lipoxygenase-1 and -2 in articular chondrocytes. Their respective metabolites, namely 13(S)-hydroxy octadecadienoic and 15(S)-hydroxyeicosatetraenoic acids, suppressed IL-1β-induced MMP-1 and MMP-13 expression in a PPARγ-dependent pathway. These data suggest that 15-lipoxygenases may have chondroprotective properties by reducing MMP-1 and MMP-13 expression.

Inhibition of the lipopolysaccharide-induced stimulation of the members of the MAPK family in human monocytes/macrophages by 4-hydroxynonenal, a product of oxidized omega-6 fatty acids

The compound 4-hydroxynonenal (4-HNE) is the major aldehyde formed during lipid peroxidation of omega-6-polyunsaturated fatty acids and has been suggested to regulate inflammatory responses because it inhibits tumor necrosis factor (TNF) mRNA production in the human monocytic cell line THP-1. Here we demonstrate that 4-HNE inhibits TNF and interleukin-1beta production in human monocytes in response to lipopolysaccharide. The main action of 4-HNE occurred at the pretranscriptional level; there was no effect on TNF mRNA production or stability when 4-HNE was added after stimulation. The mechanism of action of 4-HNE appears to be downstream of lipopolysaccharide-receptor binding. In the human monocytic MonoMac 6 cell line, 4-HNE caused selective inhibition of the activity of the mitogen-activated protein kinases p38 and ERK1/ERK2, but not JNK. However, in monocytes, the activities of all three kinases were inhibited, suggesting that the effects of 4-HNE were exerted at points upstream of ERK1/ERK2 and JNK as the levels of the phosphorylated kinases were reduced. In contrast, p38 phosphorylation was not inhibited, suggesting that 4-HNE affects kinase activity. 4-HNE also inhibited nuclear factor-kappaB activation in monocytes. In view of the roles of p38, ERK1/ERK2, JNK, and nuclear factor-kappaB in inflammation, the data suggest that 4-HNE, at nontoxic concentrations, has anti-inflammatory properties, most likely through an effect on these signaling molecules, and could lead to the development of novel treatments for inflammatory diseases.

Limiting inflammatory responses during activation of innate immunity

The idea of the importance of mounting an inflammatory response for effective immunity is supported by a multiplicity of experimental data. It is also well understood that resolution of inflammation is essential for maintaining the balance between health and disease. When the normal regulatory mechanisms are disturbed, the potential for developing chronic inflammatory diseases is increased. Inflammation is a key element in the response of the innate immune system to a variety of challenges, including those provided by bacterial and viral infection as well as by damaged or dying host cells. Here we review elements of innate immunity that lead to inflammation and some of the host mechanisms that allow for the resolution of the inflammatory responses.

Lipoxins and aspirin-triggered 15-epi-lipoxins are the first lipid mediators of endogenous anti-inflammation and resolution

Lipoxins (LXs) or the lipoxygenase interaction products are generated from arachidonic acid via sequential actions of lipoxygenases and subsequent reactions to give specific trihydroxytetraene-containing eicosanoids. These unique structures are formed during cell-cell interactions and appear to act at both temporal and spatially distinct sites from other eicosanoids produced during the course of inflammatory responses and to stimulate natural resolution. Lipoxin A4 (LXA4) and lipoxin B4 (LXB4) are positional isomers that each possesses potent cellular and in vivo actions. These LX structures are conserved across species. The results of numerous studies reviewed in this work now confirm that they are the first recognized eicosanoid chemical mediators that display both potent anti-inflammatory and pro-resolving actions in vivo in disease models that include rabbit, rat, and mouse systems. LXs act at specific GPCRs as agonists to regulate cellular responses of interest in inflammation and resolution. Aspirin has a direct impact in the LX circuit by triggering the biosynthesis of endogenous epimers of LX, termed the aspirin-triggered 15-epi-LX, that share the potent anti-inflammatory actions of LX. Stable analogs of LXA4, LXB4, and aspirin-triggered lipoxin were prepared, and several of these display potent actions in vitro and in vivo. The results reviewed herein implicate a role of LX and their analogs in many common human diseases including airway inflammation, asthma, arthritis, cardiovascular disorders, gastrointestinal disease, periodontal disease, kidney diseases and graft-vs.-host disease, as well as others where uncontrolled inflammation plays a key role in disease pathogenesis. Hence, the LX pathways and mechanisms reviewed to date in this work provide a basis for new approaches to treatment of many common human diseases that involve inflammation.