Discoidin domain receptor 1 mediates collagen-induced nitric oxide production in J774A.1 murine macrophages

Systems genetics uncover new loci containing functional gene candidates in Mycobacterium tuberculosis-infected Diversity Outbred mice

Mycobacterium tuberculosis infects two billion people across the globe, and results in 8-9 million new tuberculosis (TB) cases and 1-1.5 million deaths each year. Most patients have no known genetic basis that predisposes them to disease. Here, we investigate the complex genetic basis of pulmonary TB by modelling human genetic diversity with the Diversity Outbred mouse population. When infected with M. tuberculosis, one-third develop early onset, rapidly progressive, necrotizing granulomas and succumb within 60 days. The remaining develop non-necrotizing granulomas and survive longer than 60 days. Genetic mapping using immune and inflammatory mediators; and clinical, microbiological, and granuloma correlates of disease identified five new loci on mouse chromosomes 1, 2, 4, 16; and three known loci on chromosomes 3 and 17. Further, multiple positively correlated traits shared loci on chromosomes 1, 16, and 17 and had similar patterns of allele effects, suggesting these loci contain critical genetic regulators of inflammatory responses to M. tuberculosis. To narrow the list of candidate genes, we used a machine learning strategy that integrated gene expression signatures from lungs of M. tuberculosis-infected Diversity Outbred mice with gene interaction networks to generate scores representing functional relationships. The scores were used to rank candidates for each mapped trait, resulting in 11 candidate genes: Ncf2, Fam20b, S100a8, S100a9, Itgb5, Fstl1, Zbtb20, Ddr1, Ier3, Vegfa, and Zfp318. Although all candidates have roles in infection, inflammation, cell migration, extracellular matrix remodeling, or intracellular signaling, and all contain single nucleotide polymorphisms (SNPs), SNPs in only four genes (S100a8, Itgb5, Fstl1, Zfp318) are predicted to have deleterious effects on protein functions. We performed methodological and candidate validations to (i) assess biological relevance of predicted allele effects by showing that Diversity Outbred mice carrying PWK/PhJ alleles at the H-2 locus on chromosome 17 QTL have shorter survival; (ii) confirm accuracy of predicted allele effects by quantifying S100A8 protein in inbred founder strains; and (iii) infection of C57BL/6 mice deficient for the S100a8 gene. Overall, this body of work demonstrates that systems genetics using Diversity Outbred mice can identify new (and known) QTLs and functionally relevant gene candidates that may be major regulators of complex host-pathogens interactions contributing to granuloma necrosis and acute inflammation in pulmonary TB.

Systems genetics uncover new loci containing functional gene candidates in Mycobacterium tuberculosis-infected Diversity Outbred mice

Mycobacterium tuberculosis, the bacillus that causes tuberculosis (TB), infects 2 billion people across the globe, and results in 8-9 million new TB cases and 1-1.5 million deaths each year. Most patients have no known genetic basis that predisposes them to disease. We investigated the complex genetic basis of pulmonary TB by modelling human genetic diversity with the Diversity Outbred mouse population. When infected with M. tuberculosis, one-third develop early onset, rapidly progressive, necrotizing granulomas and succumb within 60 days. The remaining develop non-necrotizing granulomas and survive longer than 60 days. Genetic mapping using clinical indicators of disease, granuloma histopathological features, and immune response traits identified five new loci on mouse chromosomes 1, 2, 4, 16 and three previously identified loci on chromosomes 3 and 17. Quantitative trait loci (QTLs) on chromosomes 1, 16, and 17, associated with multiple correlated traits and had similar patterns of allele effects, suggesting these QTLs contain important genetic regulators of responses to M. tuberculosis. To narrow the list of candidate genes in QTLs, we used a machine learning strategy that integrated gene expression signatures from lungs of M. tuberculosis-infected Diversity Outbred mice with gene interaction networks, generating functional scores. The scores were then used to rank candidates for each mapped trait in each locus, resulting in 11 candidates: Ncf2, Fam20b, S100a8, S100a9, Itgb5, Fstl1, Zbtb20, Ddr1, Ier3, Vegfa, and Zfp318. Importantly, all 11 candidates have roles in infection, inflammation, cell migration, extracellular matrix remodeling, or intracellular signaling. Further, all candidates contain single nucleotide polymorphisms (SNPs), and some but not all SNPs were predicted to have deleterious consequences on protein functions. Multiple methods were used for validation including (i) a statistical method that showed Diversity Outbred mice carrying PWH/PhJ alleles on chromosome 17 QTL have shorter survival; (ii) quantification of S100A8 protein levels, confirming predicted allele effects; and (iii) infection of C57BL/6 mice deficient for the S100a8 gene. Overall, this work demonstrates that systems genetics using Diversity Outbred mice can identify new (and known) QTLs and new functionally relevant gene candidates that may be major regulators of granuloma necrosis and acute inflammation in pulmonary TB.

ECM-engineered electrospun fibers with an immune cascade effect for inhibiting tissue fibrosis

Tissue regeneration/fibrosis after injury is intricately regulated by the immune cascade reaction and extracellular matrix (ECM). Dysregulated cascade signal could jeopardize tissue homeostasis leading to fibrosis. Bioactive scaffolds mimicking natural ECM microstructure and chemistry could regulate the cascade reaction to achieve tissue regeneration. The current study constructed an ECM-engineered micro/nanofibrous scaffold using self-assembled nanofibrous collagen and decorin (DCN)-loaded microfibers to regulate the immune cascade reaction. The ECM-engineered scaffold promoted anti-inflammatory and pro-regenerative effects, M2 polarization of macrophages, by nanofibrous collagen. The ECM-engineered scaffold could release DCN to inhibit inflammation-associated fibrous angiogenesis. Yet, to prevent excessive M2 activity leading to tissue fibrosis, controlled release of DCN was expected to elicit M1 activity and achieve M1/M2 balance in the repair process. Regulated cascade reaction guided favorable crosstalk between macrophages, endothelial cells and fibroblasts by proximity. Additionally, decorin could also antagonize TGF-β1 via TGF-β/Smad3 pathway to suppress fibrotic activity of fibroblasts. Hence, ECM-engineered scaffolds could exert effective regulation of the immune cascade reaction by microstructure and DCN release and achieve the balance between tissue fibrosis and regeneration. STATEMENT OF SIGNIFICANCE: With the incidence of up to 74.6%, failed back surgery syndrome (FBSS) has been a lingering issue in spine surgery, which poses a heavy socio-economic burden to society. Epidural fibrosis is believed to be responsible for the onset of FBSS. Current biomaterial-based strategies treating epidural fibrosis mainly rely on physical barriers and unidirectional suppression of inflammation. Regulation of the immune cascade reaction for inhibiting fibrosis has not been widely studied. Based on the simultaneous regulation of M1/M2 polarization and intercellular crosstalk, the ECM-engineered micro/nanofibrous scaffolds constructed in the current study could exert an immune cascade effect to coordinate tissue regeneration and inhibit fibrosis. This finding makes a significant contribution in the development of a treatment for epidural fibrosis and FBSS.

A network map of discoidin domain receptor 1(DDR1)-mediated signaling in pathological conditions

Discoidin domain receptor 1 (DDR1) is one of the receptors that belong to a family of non-integrin collagen receptors. In common, DDR1 is predominantly found in epithelial and smooth muscle cells and its mainly involved in organogenesis during embryonic development. However, it's also overexpressed in several pathological conditions, including cancer and inflammation. The DDR1 is reported in numerous cancers, including breast, prostate, pancreatic, bladder, lung, liver, pituitary, colorectal, skin, gastric, glioblastoma, and inflammation. DDR1 activates through the collagen I, IV, IGF-1/IGF1R, and IGF2/IR, regulating downstream signaling molecules such as MAPKs, PI3K/Akt, and NF-kB in diseases. Despite its biomedical importance, there is a lack of consolidated network map of the DDR1 signaling pathway, which prompted us for curation of literature data pertaining to the DDR1 system following the NetPath criteria. We present here the compiled pathway map comprises 39 activation/inhibition events, 17 catalysis events, 22 molecular associations, 65 gene regulation events, 35 types of protein expression, and two protein translocation events. The detailed DDR1 signaling pathway map is made freely accessible through the WikiPathways Database ( https://www.wikipathways.org/index.php/ Pathway: https://www.wikipathways.org/index.php/Pathway:WP5288 ).

Effects of DDR1 on migration and adhesion of periodontal ligament cells and the underlying mechanism

BACKGROUND AND OBJECTIVE

As one of the widely expressed cell surface receptors binding to collagen, the most abundant component of the extracellular matrix (ECM), knowledge of the expression, functions, and mechanisms underlying the role of discoidin domain receptor 1 (DDR1) in human periodontal ligament cells (hPDLCs) is incomplete. This study determined the expression of DDR1 in hPDLCs and the effect of DDR1 upon migration and adhesion to hPDLCs, as well as the related regulatory mechanisms.

MATERIALS AND METHODS

The expression of DDR1 and the DDR1 isoforms in hPDLCs from six donors were tested. The migratory ability (horizontal and vertical) and adhesive capacity of hPDLCs with or without specific knockdown of DDR1 were evaluated. After treatment with MEK-ERK1/2 inhibitors (PD98059 and U0126) with or without RNAi, the migratory and adhesive capacity of hPDLCs were re-tested. Western blotting was performed to verify p-MEK1/2 and p-ERK1/2, the key factors of the MEK-ERK1/2 signaling pathways.

RESULTS

DDR1 was detected in hPDLCs in the mRNA and protein level; DDR1b was the dominant isoform. Knockdown of DDR1 almost halved the migratory capacity and significantly downregulated the adhesive capacity of hPDLCs. The use of MEK-ERK1/2 inhibitors caused declined migratory and adhesive capacity of hPDLCs as well. After DDR1 was knocked down, the expression of p-MEK and p-ERK protein declined significantly while total MEK and ERK showed no obvious change, which means the ratio of p-MEK/MEK and p-ERK/ERK was markedly reduced.

CONCLUSIONS

DDR1 plays an important role in the migration and adhesion of hPDLCs and might be regulated via the MEK-ERK1/2 signaling pathway.

Immune Modulatory Properties of Collagen in Cancer

During tumor growth the extracellular matrix (ECM) undergoes dramatic remodeling. The normal ECM is degraded and substituted with a tumor-specific ECM, which is often of higher collagen density and increased stiffness. The structure and collagen density of the tumor-specific ECM has been associated with poor prognosis in several types of cancer. However, the reason for this association is still largely unknown. Collagen can promote cancer cell growth and migration, but recent studies have shown that collagens can also affect the function and phenotype of various types of tumor-infiltrating immune cells such as tumor-associated macrophages (TAMs) and T cells. This suggests that tumor-associated collagen could have important immune modulatory functions within the tumor microenvironment, affecting cancer progression as well as the efficacy of cancer immunotherapy. The effects of tumor-associated collagen on immune cells could help explain why a high collagen density in tumors is often correlated with a poor prognosis. Knowledge about immune modulatory functions of collagen could potentially identify targets for improving current cancer therapies or for development of new treatments. In this review, the current knowledge about the ability of collagen to influence T cell activity will be summarized. This includes direct interactions with T cells as well as induction of immune suppressive activity in other immune cells such as macrophages. Additionally, the potential effects of collagen on the efficacy of cancer immunotherapy will be discussed.

Silencing of sinusoidal DDR1 reduces murine liver metastasis by colon carcinoma

Liver metastasis depends on the collagenous microenvironment generated by hepatic sinusoidal cells (SCs). DDR1 is an atypical collagen receptor linked to tumor progression, but whether SCs express DDR1 and its implication in liver metastasis remain unknown. Freshly isolated hepatic stellate cells (HSCs), Kupffer cells (KCs), and liver sinusoidal endothelial cells (LSECs), that conform the SCs, expressed functional DDR1. HSCs expressed the largest amounts. C26 colon carcinoma secretomes increased DDR1 phosphorylation in HSCs and KCs by collagen I. Inhibition of kinase activity by DDR1-IN-1 or mRNA silencing of DDR1 reduced HSCs secretion of MMP2/9 and chemoattractant and proliferative factors for LSECs and C26 cells. DDR1-IN-1 did not modify MMP2/9 in KCs or LSECs secretomes, but decreased the enhancement of C26 migration and proliferation induced by their secretomes. Gene array showed that DDR1 silencing downregulated HSCs genes for collagens, MMPs, interleukins and chemokines. Silencing of DDR1 before tumor inoculation reduced hepatic C26 metastasis in mice. Silenced livers bore less tumor foci than controls. Metastatic foci in DDR1 silenced mice were smaller and contained an altered stroma with fewer SCs, proliferating cells, collagen and MMPs than foci in control mice. In conclusion, hepatic DDR1 promotes C26 liver metastasis and favors the pro-metastatic response of SCs to the tumor.

A pathologic two-way street: how innate immunity impacts lung fibrosis and fibrosis impacts lung immunity

Lung fibrosis is characterised by the accumulation of extracellular matrix within the lung and is secondary to both known and unknown aetiologies. This accumulation of scar tissue limits gas exchange causing respiratory insufficiency. The pathogenesis of lung fibrosis is poorly understood, but immunologic‐based treatments have been largely ineffective. Despite this, accumulating evidence suggests that innate immune cells and receptors play important modulatory roles in the initiation and propagation of the disease. Paradoxically, while innate immune signalling may be important for the pathogenesis of fibrosis, there is also evidence to suggest that innate immune function against pathogens may be impaired, leading to dysregulated and/or impaired host defence. This review summarises the evidence for this pathologic two‐way street, highlights new concepts of pathogenesis and recommends future directions for research emphasis.

6-Methoxyflavonols from the aerial parts of Tetragonia tetragonoides (Pall.) Kuntze and their anti-inflammatory activity

Dried aerial parts of Tetragonia tetragonoides were extracted with 70% EtOH, and the evaporated residue was successively separated into EtOAc, n-BuOH, and H₂O fractions. As a result of repeated SiO₂, ODS, and Sephadex LH-20 column chromatography, four new 6-methoxyflavonol glycosides (2-4, 8) along with four known ones (1, 5-7) were isolated. Several spectroscopic data led to determination of chemical structures for four new 6-methoxyflavonol glycosides (2-4, 8) and four known ones, 6-methoxykaempferol 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl-7-O-(6‴'-(E)-caffeoyl)-β-d-glucopyranoside (1), 6-methoxyquercetin (5), 6-methoxykaempferol (6), and 6-methoxykaempferol 7-O-β-d-glucopyranoside (7). Methoxyflavonol glycosides 2-8 also have never been reported from T. tetragonoides in this study. 6-Methoxyflavonols 5 and 6 showed high radical scavenging potential in DPPH and ABTS test. Also, all compounds showed significant anti-inflammatory activities such as reduction of NO and PGE₂ formation and suppression of TNF-α, IL-6, IL-1β, iNOS, and COX-2 expression in LPS-stimulated RAW 264.7 macrophages. In general, the aglycones exhibited higher activity than the glycosides. In addition, quantitative analysis of 6-methoxyflavonols in the T. tetragonoides aerial parts extract was conducted through HPLC.

DDR1 role in fibrosis and its pharmacological targeting

Discoidin domain receptor1 (DDR1) is a collagen activated receptor tyrosine kinase and an attractive anti-fibrotic target. Its expression is mainly limited to epithelial cells located in several organs including skin, kidney, liver and lung. DDR1's biology is elusive, with unknown downstream activation pathways; however, it may act as a mediator of the stromal-epithelial interaction, potentially controlling the activation state of the resident quiescent fibroblasts. Increased expression of DDR1 has been documented in several types of cancer and fibrotic conditions including skin hypertrophic scars, idiopathic pulmonary fibrosis, cirrhotic liver and renal fibrosis. The present review article focuses on: a) detailing the evidence for a role of DDR1 as an anti-fibrotic target in different organs, b) clarifying DDR1 tissue distribution in healthy and diseased tissues as well as c) exploring DDR1 protective mode of action based on literature evidence and co-authors experience; d) detailing pharmacological efforts attempted to drug this subtle anti-fibrotic target to date.

Discoidin domain receptor 1 promotes Th17 cell migration by activating the RhoA/ROCK/MAPK/ERK signaling pathway

Effector T cell migration through the tissue extracellular matrix (ECM) is an important step of the adaptive immune response and in the development of inflammatory diseases. However, the mechanisms involved in this process are still poorly understood. In this study, we addressed the role of a collagen receptor, the discoidin domain receptor 1 (DDR1), in the migration of Th17 cells. We showed that the vast majority of human Th17 cells express DDR1 and that silencing DDR1 or using the blocking recombinant receptor DDR1:Fc significantly reduced their motility and invasion in three-dimensional (3D) collagen. DDR1 promoted Th17 migration by activating RhoA/ROCK and MAPK/ERK signaling pathways. Interestingly, the RhoA/ROCK signaling module was required for MAPK/ERK activation. Finally, we showed that DDR1 is important for the recruitment of Th17 cells into the mouse dorsal air pouch containing the chemoattractant CCL20. Collectively, our results indicate that DDR1, via the activation of RhoA/ROCK/MAPK/ERK signaling axis, is a key pathway of effector T cell migration through collagen of perivascular tissues. As such, DDR1 can contribute to the development of Th17-dependent inflammatory diseases.

Human Th17 Migration in Three-Dimensional Collagen Involves p38 MAPK

T cell migration across extracellular matrix (ECM) is an important step of the adaptive immune response but is also involved in the development of inflammatory autoimmune diseases. Currently, the molecular mechanisms regulating the motility of effector T cells in ECM are not fully understood. Activation of p38 MAPK has been implicated in T cell activation and is critical to the development of immune and inflammatory responses. In this study, we examined the implication of p38 MAPK in regulating the migration of human Th17 cells through collagen. Using specific inhibitor and siRNA, we found that p38 is necessary for human Th17 migration in three-dimensional (3D) collagen and that 3D collagen increases p38 phosphorylation. We also provide evidence that the collagen receptor, discoidin domain receptor 1 (DDR1), which promotes Th17 migration in 3D collagen, is involved in p38 activation. Together, our findings suggest that targeting DDR1/p38 MAPK pathway could be beneficial for the treatment of Th17-mediated inflammatory diseases. J. Cell. Biochem. 118: 2819-2827, 2017. © 2017 Wiley Periodicals, Inc.

Anti-Inflammatory Effects and Mechanisms of Action of Coussaric and Betulinic Acids Isolated from Diospyros kaki in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

Diospyros kaki Thunb. is widely distributed in East Asian countries, its leaves being mainly used for making tea. In this study, coussaric acid (CA) and betulinic acid (BA), both triterpenoid compounds, were obtained from D. kaki leaf extracts through bioassay-guided isolation. CA and BA showed anti-inflammatory effects via inhibition of the nuclear factor-κB (NF-κB) pathway, providing important information on their anti-inflammatory mechanism. Furthermore, they markedly inhibited nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages, and suppressed tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) levels. Furthermore, they decreased protein expression of inducible nitric oxide synthase and cyclooxygenase-2. Pre-treatment with CA and BA inhibited LPS-induced NF-κB. We further examined the effects of CA and BA on heme oxygenase (HO)-1 expression in RAW 264.7 macrophages: BA induced HO-1 protein expression in a dose-dependent manner, while CA had no effect. We also investigated whether BA treatment induced nuclear translocation of Nrf2. BA inhibited LPS-induced NF-κB-binding activity, as well as pro-inflammatory mediator and cytokine production (e.g., NO, PGE₂, TNF-α, IL-1β, IL-6), by partial reversal of this effect by SnPP, an inhibitor of HO-1. These findings further elucidate the anti-inflammatory mechanism of CA and BA isolated from D. kaki.

Effect of silymarin on gluconeogenesis and lactate production in exercising rats

In this study, we investigated the effects of silymarin (SM) on gluconeogenesis during exercise in rats. After 4 weeks of exercise, blood samples, liver, and skeletal muscle tissues were collected, and the levels of triglycerides (TG), lactate, peroxisome proliferator activated receptor gamma (PPARγ), phosphoenol pyruvate carboxykinase (PEPCK), pyruvate dehydrogenase kinase 4 (PDK4), and phosphorylated 5-AMP activated protein kinase (AMPK) were measured. The TG and lactate level of the serum were reduced. In addition, the expression of Akt, PEPCK, and PPARγ in liver was decreased as well as the expression of AMPK in muscle. On the contrary, the level of PDK4 in muscle was increased. These results showed that that administration of SM ameliorated exerciseinduced gluconeogenesis and β-oxidation through the regulation of PPARγ, PEPCK, and PDK4. Thus, intake of SM during exercise may improve endurance by modulating of the metabolism of glucose, lipids, and lactate.

Rutin suppresses atopic dermatitis and allergic contact dermatitis

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) is a common allergic inflammatory skin disease caused by a combination of eczematous, scratching, pruritus and cutaneous sensitization with allergens. The aim of our study was to examine whether rutin, a predominant flavonoid having anti-inflammatory and antioxidative potential, modulates AD and ACD symptoms. We established an atopic dermatitis model in BALB/c mice by repeated local exposure of house dust mite ( Dermatophagoides farinae) extract (DFE) and 2,4-dinitrochlorobenzene (DNCB) to the ears. In addition, 2,4-dinitroflourobenzene-sensitized a local lymph node assay was used for the ACD model. Repeated alternative treatment of DFE/DNCB caused AD symptoms. Topical application of rutin reduced AD based on ear thickness and histopathological analysis, in addition to serum IgE levels. Rutin inhibited mast cell infiltration into the ear and serum histamine level. Rutin suppressed DFE/DNCB-induced expression of interleukin (IL)-4, IL-5, IL-13, IL-31, IL-32 and interferon (INF)- γ in the tissue. In addition, rutin suppressed ACD based on ear thickness and lymphocyte proliferation, serum IgG2a levels, and expression of INF- γ, IL-4, IL-5, IL-10, IL-17 and tumour necrosis factor- α in ACD ears. This study demonstrates that rutin inhibits AD and ACD, suggesting that rutin might be a candidate for the treatment of allergic skin diseases.

Discoidin domain receptor 1 protein is a novel modulator of megakaryocyte-collagen interactions

Growing evidence demonstrates that extracellular matrices regulate many aspects of megakaryocyte (MK) development; however, among the different extracellular matrix receptors, integrin α2β1 and glycoprotein VI are the only collagen receptors studied in platelets and MKs. In this study, we demonstrate the expression of the novel collagen receptor discoidin domain receptor 1 (DDR1) by human MKs at both mRNA and protein levels and provide evidence of DDR1 involvement in the regulation of MK motility on type I collagen through a mechanism based on the activity of SHP1 phosphatase and spleen tyrosine kinase (Syk). Specifically, we demonstrated that inhibition of DDR1 binding to type I collagen, preserving the engagement of the other collagen receptors, glycoprotein VI, α2β1, and LAIR-1, determines a decrease in MK migration due to the reduction in SHP1 phosphatase activity and consequent increase in the phosphorylation level of its main substrate Syk. Consistently, inhibition of Syk activity restored MK migration on type I collagen. In conclusion, we report the expression and function of a novel collagen receptor on human MKs, and we point out that an increasing level of complexity is necessary to better understand MK-collagen interactions in the bone marrow environment.

Subchronic effects of perfluorooctanesulfonate exposure on inflammation in adult male C57BL/6 mice

Previous studies indicate that exposure to perfluorooctanesulfonate (PFOS), a ubiquitous and highly persistent environmental contaminant, induces immunotoxicity in mice. However, few studies have specifically assessed the effects of PFOS on inflammation. This study utilized a standard 60-day oral exposure period to assess the effects of PFOS on the response of inflammatory cytokines [tumor necrosis factor α (TNF-α), interleukin-1 β (IL-1β), and interleukin-6 (IL-6)]. Adult male C57BL/6 mice were dosed daily by oral gavage with PFOS at 0, 0.0083, 0.0167, 0.0833, 0.4167, 0.8333 or 2.0833 mg/kg/day to yield a targeted Total Administered Dose (TAD) over 60 days of 0, 0.5, 1, 5, 25, 50, or 125 mg PFOS/kg, respectively. The percentage of peritoneal macrophages (CD11b+ cells) was significantly increased at concentrations ≥ 1 mg PFOS/kg TAD in a dose-dependent manner. Ex vivo IL-1β production by peritoneal macrophages was elevated substantially at concentrations of ≥ 5 mg PFOS/kg TAD. Moreover, PFOS exposure markedly enhanced the ex vivo production of TNF-α, IL-1β and IL-6 by peritoneal and splenic macrophages when stimulated either in vitro or in vivo with lipopolysaccharide (LPS). The serum levels of these inflammatory cytokines observed in response to in vivo stimulation with LPS were elevated substantially by exposure to PFOS. PFOS exposure elevated the expression of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and proto-oncogene, c-myc, in the spleen. These data suggest that exposure to PFOS modulates the inflammatory response, and further research is needed to determine the mechanism of action.

Perfluorooctanoic acid induces mast cell-mediated allergic inflammation by the release of histamine and inflammatory mediators

Perfluorooctanoic acid (PFOA) has unique physical and chemical characteristics, water and oil repellency, thermal stability, and surfactant properties. PFOA has been regularly found in the blood of animals and humans worldwide, and has become an increasing concern because of its adverse effects in immune system. However, the role of PFOA in the allergic inflammation is not well-known. To further extend the immunotoxicity of PFOA, we examined the role of PFOA on the mast cell-mediated allergic inflammation and studied the possible mechanism of action. PFOA dose- and time-dependently increased histamine release from mast cells and serum histamine by the induction of intracellular calcium. PFOA exacerbated the IgE-dependent local allergic reaction in the mouse allergy model. PFOA induced gene expression of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 in mast cells. The inducing effect of PFOA on the pro-inflammatory cytokines was nuclear factor-κB, p38 mitogen-activated protein kinase, and caspase-1 dependent. Furthermore, the activation of cyclooxygenase-2 by PFOA suggests the induction of allergic inflammatory mediators by the PFOA. Our findings provide evidence that PFOA, the known immunotoxic agent, induces mast cell-derived allergic inflammatory reactions by histamine release and expression of pro-inflammatory cytokines.

Suppression of dust mite extract and 2,4-dinitrochlorobenzene-induced atopic dermatitis by the water extract of Lindera obtusiloba

ETHNOPHARMACOLOGICAL RELEVANCE

The Lindera obtusiloba has been used in traditional medicine for the treatment of inflammation and dermatitis. In this study, we investigated the effect of topical application of Lindera obtusiloba water extract (LOWE) on the house dust mite extract (Dermatophagoides farinae extract, DFE) and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD).

MATERIALS AND METHODS

We established AD model in BALB/c mice by repeated local exposure of DFE/DNCB to the ears. After a topical application of LOWE on the skin lesions, the epidermal thickness, mast cell infiltration, and serum immunoglobulin E (IgE) and histamine were measured. In addition, the gene expression of interleukin (IL)-4, IL-13, IL-31, and tumor necrosis factor (TNF)-α in the ears was assayed.

RESULTS

LOWE reduced AD symptoms based on ear thickness, histopathological analysis, and serum IgE levels. LOWE inhibited mast cell infiltration into the ear and elevation of serum histamine in AD model. Moreover, LOWE suppressed DFE/DNCB-induced expression of IL-4, IL-13, IL-31, and TNF-α in the ears.

CONCLUSIONS

Our results showed that topical application of LOWE exerts beneficial effects in AD symptoms, suggesting that LOWE might be a candidate for the treatment of AD.

The comparative effects of mesoporous silica nanoparticles and colloidal silica on inflammation and apoptosis

Mesoporous silica (MPS), synthesized via the supramolecular polymer templating method, is one of the most attractive nanomaterials for biomedical applications, such as drug delivery systems, labeling, and tissue engineering. The significant difference between MPS and general silica (colloidal silica) is the pore architectures, such as specific surface area and pore volume. The pore structures of nanomaterials have been considered to be one of the key conditions, causing nanotoxicity due to their different efficiency of cellular uptake and immune response. We first studied the influence of pore structural conditions of silica nanoparticles on both inflammation and apoptosis, in vitro and in vivo, by comparing MPS and colloidal silica, and defined underlying mechanisms of action. Both the MPS and colloidal silica nanoparticles are produced by almost similar synthetic conditions, except the use of polymer template for MPS. The specific surface area of colloidal silica and MPS was 40 and 1150 m(2) g(-1), respectively, while other conditions, including particle size (100 nm) and shape (spherical), were kept constant. In both MTT assay and FACS analysis, MPS nanoparticles showed significantly less cytotoxicity and apoptotic cell death than colloidal silica nanoparticles. MPS nanoparticles induced lower expression of pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, in macrophages. The reduced inflammatory response and apoptosis elicited by MPS nanoparticles were resulting from the reduction of mitogen-activated protein kinases, nuclear factor-κB, and caspase 3. In addition, using the local lymph node assay, a standalone in vivo method for hazard identification of contact hypersensitivity, we showed that colloidal silica nanoparticles act as an immunogenic sensitizer and induce contact hypersensitivity but not MPS nanoparticles. In conclusion, the pore architecture of silica nanoparticles greatly influences their biocompatibility and should be carefully designed. The MPS nanoparticles exhibit better biocompatibility than colloidal silica and promise excellent potential usage in the field of biomedical and biotechnological applications.

Elsholtzia ciliata inhibits mast cell-mediated allergic inflammation: role of calcium, p38 mitogen-activated protein kinase and nuclear factor-{kappa}B

Mast cell-mediated allergic reaction is involved in many diseases such as asthma and allergic rhinitis. Therefore, discovery of drugs for the prevention or treatment of allergic disease is an important topic in human health. In this study, we evaluated the effects of water extract of Elsholtzia ciliata (Thunb.) Hyland (Labiatae) (WEEC) on mast cell-mediated allergic inflammation and studied the possible mechanisms of action. WEEC inhibited compound 48/80-induced systemic and immunoglobulin E-mediated local anaphylaxis, and serum histamine release in mice. WEEC reduced intracellular calcium levels and downstream histamine release from human mast cells (HMC-1) activated with phorbol 12-myristate 13-acetate and calcium ionophore A23187. In addition, WEEC decreased gene expression and secretion of proinflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1β and IL-6 in HMC-1. The inhibitory effect of WEEC on cytokine expression was nuclear factor (NF)-κB and p38 mitogen-activated protein kinase (MAPK) dependent. Our results indicate that WEEC inhibits mast cell-mediated allergic inflammatory reactions by suppressing histamine release and proinflammatory cytokine expression, and involvement of calcium, NF-κB and p38 MAPK in these effects.

Analysis on migration and activation of live macrophages on transparent flat and nanostructured titanium

The immunotoxicity of implanted nanostructured titanium is a paramount issue for vascular, dental and orthopedic applications. However, it has been unclear whether implanted surface nanostructures can inhibit or aggrevate inflammatory responses. Herein, macrophage activation, as evidence of migration, on transparent flat and nanostructured titanium correlated with pro-inflammatory protein synthesis and cytokine release. Through the real-time monitoring of initial cytoskeleton variations, this study identified that macrophage movement was restricted on nanostructured titanium compared to flat titanium surfaces. Furthermore, nanostructured titanium elicited secretion of fewer pro-inflammatory enzyme molecules and cytokines, as well as reduced nitric oxide production. All results collectively indicated that initial macrophage activation can be mitigated by nanoscale surface topography alone, without modification of surface chemistry or stiffness.

DA-9601 suppresses 2, 4-dinitrochlorobenzene and dust mite extract-induced atopic dermatitis-like skin lesions

DA-9601 (Stillen™) is a novel anti-peptic formulation prepared from the ethanol extracts of Artemisia asiatica possessing anti-oxidative, anti-allergic and anti-inflammatory activities. However, their effect on atopic dermatitis (AD) has not been studied yet. In this study, we report that topical application of DA-9601 suppressed house dust mite extract (Dermatophagoides farinae extract, DFE) and 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in BALB/c mice model. We established atopic dermatitis model in BALB/c mice by repeated local exposure of DFE/DNCB to the ears. Repeated alternative treatment of DFE/DNCB caused AD-like lesions. DA-9601 reduced AD-like skin lesions based on ear thickness and histopathological analysis, and serum IgE levels. DA-9601 inhibited mast cell infiltration into the ear and elevation of serum histamine in AD model. In addition, DA-9601 suppressed DFE/DNCB-induced expression of IL-4, IL-13, IL-31, and TNF-α in the ears. Taken together, our results showed that topical application of DA-9601 exerts beneficial effects in animal model of AD, suggesting that DA-9601 might be a candidate for the treatment of AD.

Chrysin suppresses mast cell-mediated allergic inflammation: involvement of calcium, caspase-1 and nuclear factor-κB

A great number of people are suffering from allergic inflammatory diseases such as asthma, atopic dermatitis, and sinusitis. Therefore discovery of drugs for the treatment of these diseases is an important subject in human health. Chrysin (5,7-dihydroxyflavone) is a natural flavonoid contained in propolis, blue passion flower, and fruits. Several studies reported that chrysin has beneficial effects including anti-tumor and anti-oxidant activities. The aim of the present study was to elucidate whether chrysin modulates the allergic inflammatory reaction and to study its possible mechanisms of action using mast cell-based in vitro and in vivo models. Chrysin inhibited immediate-type systemic hypersensitivity and serum histamine release. Chrysin attenuated immunoglobulin E-mediated local anaphylaxis. These inhibitory effects of chrysin on the systemic and local allergic reaction were more potent than cromolyn, a known anti-allergic drug. Chrysin reduced histamine release from mast cells. The inhibitory effect of chrysin on the histamine release was mediated by the modulation of intracellular calcium. In addition, chrysin decreased gene expression of pro-inflammatory cytokines such as, tumor necrosis factor-α, IL (interleukin)-1β, IL-4, and IL-6 in mast cells. The inhibitory effect of chrysin on the pro-inflammatory cytokine was nuclear factor-κB and caspase-1 dependent. Our findings provide evidence that chrysin inhibits mast cell-derived allergic inflammatory reactions by blocking histamine release and pro-inflammatory cytokine expression, and suggest the mechanisms of action. Furthermore, in vivo and in vitro anti-allergic inflammatory effect of chrysin suggests a possible therapeutic application of this agent in allergic inflammatory diseases.

Suppression of mast-cell-mediated allergic inflammation by Lindera obtusiloba

Allergic disease is a consequence of exposure to normally innocuous substances that elicit the activation of mast cells. Mast-cell-mediated allergic response is involved in many diseases such as anaphylaxis, allergic rhinitis, asthma and atopic dermatitis. The discovery of drugs for the treatment of allergic disease is an important subject in human health. In this study, we investigated the effect of Lindera obtusiloba water extract (LOWE) on the mast-cell-mediated allergic inflammation and possible mechanism of action using in vitro and in vivo models. LOWE reduced histamine release from various types of mast cells activated by immunoglobulin E (IgE) or phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI). The inhibitory effect of LOWE on histamine release was mediated by calcium signal. LOWE decreased the PMACI-stimulated gene expression of proinflammatory cytokines such as tumor necrosis factor-α and interleukin-6 in human mast cells. The inhibitory effect of LOWE on the proinflammatory cytokines was nuclear factor (NF)-κB dependent. In addition, LOWE suppressed compound 48/80-induced systemic allergic reaction and serum histamine release in mice and IgE-mediated local allergic reactions. Our results indicate that LOWE inhibits mast-cell-derived allergic inflammation and involvement of calcium, histamine, proinflammatory cytokines and NF-κB in these effects.

1,2,3,6-tetra-O-galloyl-beta-D-allopyranose gallotannin isolated, from Euphorbia jolkini, attenuates LPS-induced nitric oxide production in macrophages

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including vasodilatation and macrophage-mediated immunity. Macrophages express inducible NO synthase (iNOS) and produce NO after lipopolysaccharide (LPS) stimulation. Gallotannins are water-soluble polyphenols with wide-ranging biological activities. Various chemical structures of gallotannins occurring in medicinal and food plants that are used worldwide showed several remarkable biological and pharmacological activities. In the present study, we examined the inhibitory effects of gallotannin 1,2,3,6-tetra-O-galloyl-beta-D-allopyranose (GT24) isolated from Euphorbia jolkini on the LPS-induced NO production and underlying mechanisms of action. GT24 dose-dependently decreased LPS-induced NO production and iNOS expression in J774A.1 macrophages. In addition, GT24 inhibited LPS-induced activation of nuclear factor (NF)-kappaB as indicated by inhibition of degradation of I-kappaBalpha, nuclear translocation of NF-kappaB, and NF-kappaB dependent gene reporter assay. Our results suggest that GT24 possesses an inhibitory effect on the LPS-induced inflammatory reaction.

Meoruh wine suppresses mast cell-mediated allergic inflammation

In this study, we investigated the effect of the Meoruh wine (MW), a Korean traditional wine made by the fruits of Vitis amurensis Rupr. (Vitaceae) on the mast cell-mediated allergic inflammation and studied the possible mechanism of action. Mast cell-mediated allergic disease is involved in many diseases such as anaphylaxis, rhinitis, asthma, and atopic dermatitis. MW inhibited compound 48/80-induced systemic anaphylaxis and serum histamine release in a dose-dependent manner in mice. MW decreased immunoglobulin E-mediated local allergic reactions, passive cutaneous anaphylaxis. MW dose-dependently reduced histamine release from human mast cells activated by phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI). The inhibitory effect of MW on histamine release was mediated by suppression of intracellular calcium. In addition, MW attenuated the PMACI-stimulated expression of pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, and IL-8 in human mast cells. The inhibitory effect of MW on these pro-inflammatory cytokines was nuclear factor (NF)-κB dependent. Our findings provide evidence that MW inhibits mast cell-derived allergic inflammatory reactions and involvement of calcium, pro-inflammatory cytokines and NF-κB in these effects.

Anti-allergic inflammatory activity of the fruit of Prunus persica: role of calcium and NF-kappaB

Mast cell-mediated allergic symptoms are involved in many diseases, such as asthma and sinusitis. In this study, we investigated the effect of ethanol extract of fruits of Prunus persica (L) Batsch (FPP) on the mast cell-mediated allergic inflammation and studied the possible mechanism of action. FPP dose-dependently inhibited compound 48/80-induced systemic anaphylaxis and immunoglobulin E-mediated local allergic reactions. Histamine releasing from mast cells was reduced by FPP, which was mediated by modulation of intracellular calcium. In addition, FPP attenuated the phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-stimulated expression and secretion of pro-inflammatory cytokines in human mast cells. The inhibitory effect of FPP on pro-inflammatory cytokines was nuclear factor (NF)-kappaB dependent. Our findings provide evidence that FPP inhibits mast cell-derived allergic inflammation and involvement of calcium and NF-kappaB in these effects.

Clinopodium gracile inhibits mast cell-mediated allergic inflammation: involvement of calcium and nuclear factor-kappaB

Mast cell-mediated allergic disease is involved in many diseases such as anaphylaxis, rhinitis, asthma and atopic dermatitis. The discovery of drugs for the treatment of allergic disease is an important subject in human health. In this study, we investigated the effect of the water extract of Clinopodium gracile Matsum var. multicaule (WECG) on the mast cell-mediated allergic inflammation and studied the possible mechanism of action. WECG inhibited compound 48/80-induced systemic anaphylaxis and immunoglobulin E-mediated cutaneous anaphylaxis in a dose-dependent manner. WECG dose-dependently reduced histamine release from rat peritoneal mast cells and human mast cells. The inhibitory effect of WECG on histamine release was mediated by the modulation of intracellular calcium. In addition, WECG attenuated the phorbol 12-myristate 13-acetate and calcium ionophore A23187-stimulated gene expression and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha and interleukin-6 in human mast cells. The inhibitory effect of WECG on these proinflammatory cytokines was nuclear factor-kappaB (NF-kappaB) dependent. Our findings provide evidence that WECG inhibits mast cell-derived allergic inflammation and involvement of calcium and NF-kappaB in these effects.

Increased cell and matrix accumulation during atherogenesis in mice with vessel wall-specific deletion of discoidin domain receptor 1

RATIONALE

Discoidin domain receptor (DDR)1 is a collagen receptor expressed on both smooth muscle cells (SMCs) and macrophages, where it plays important roles regulating cell and matrix accumulation during atherogenesis. Systemic deletion of DDR1 resulted in attenuated plaque growth but accelerated matrix accumulation in LDLR-deficient mice. Deletion of DDR1 solely on bone marrow-derived cells resulted in decreased macrophage accumulation and plaque growth but no change in matrix accumulation.

OBJECTIVE

These findings led us to hypothesize that accelerated matrix accumulation was attributable to the increased synthetic ability of Ddr1(-/-) resident vascular wall SMCs.

METHODS AND RESULTS

We used bone marrow transplantation to generate chimeric mice and investigate the role of SMC DDR1 during atherogenesis. Mice with deficiency of DDR1 in vessel wall-derived cells (Ddr1(+/+-->-/-)) or control mice (Ddr1(+/+-->+/+)) were fed an atherogenic diet for 12 weeks. We observed a 3.8-fold increase in the size of aortic sinus plaques in Ddr1(+/+-->-/-) compared to Ddr1(+/+-->+/+) mice. This was attributed to pronounced accumulation of collagen, elastin, proteoglycans, and fibronectin and resulted in a thickened fibrous cap. The enhanced matrix accumulation decreased the proportion of plaque area occupied by cells but was associated with a shift in the cellular composition of the lesions toward increased numbers of vessel wall-derived SMCs compared to bone marrow-derived macrophages. In vitro studies confirmed that Ddr1(-/-) SMCs expressed more matrix, proliferated more, and migrated farther than Ddr1(+/+) SMCs.

CONCLUSIONS

DDR1 expression on resident vessel wall SMCs limits proliferation, migration and matrix accumulation during atherogenesis.

Perfluorooctanoic acid alters T lymphocyte phenotypes and cytokine expression in mice

Perfluorooctanoic acid (PFOA) has been used in commercial applications and detected in environmental matrices. This study focuses on whether PFOA affects the function of immune organs (spleen and thymus). Male ICR mice were exposed to 0, 2, 10, 50, and 250 ppm of PFOA in drinking water for 21 days. PFOA differently altered T lymphocyte populations. In the spleen, all doses of PFOA decreased CD8(+) lymphocytes; CD4(+) lymphocytes were increased by 50 and 250 ppm of PFOA. Exposure to 250 ppm of PFOA increased CD8(+) lymphocytes in the thymus. In the histopathological evaluation, the spleen of 250 ppm PFOA-treated groups revealed the increase of lymphoid hyperplasia of white pulp without significant alteration of red pulp. The thymus of 250 ppm PFOA-treated group showed decreased thickness of the cortex and medulla, but lymphoid cells were more densely arranged. PFOA elevated the expression of proinflammatory cytokines (tumor necrosis factor alpha, interleukin-1beta, and interleukin-6) in the spleen, and proto-oncogene, c-myc, in the spleen and thymus. In conclusion, our data demonstrated that PFOA has an immunomodulatory effect by altering T lymphocyte phenotypes and gene expression of proinflammatory cytokines.

PSC833, cyclosporine analogue, downregulates MDR1 expression by activating JNK/c-Jun/AP-1 and suppressing NF-kappaB

PURPOSE

Multidrug resistance (MDR) is one of the major causes of clinical cancer chemotherapy failure. PSC833 is well known as a non-immunosuppressant cyclosporine analogue that functionally inhibits P-glycoprotein (Pgp), a product of the MDR1 gene. We investigated whether PSC833 could also alter MDR1 expression and, if so, which mitogen-activated protein kinases (MAPKs) and nuclear factor-kappaB (NF-kappaB) pathways were involved in this event.

METHODS

MTT assay and flow cytometry were used for the analysis of cytotoxicity and intracellular drug accumulation, respectively. RT-PCR and Western blot assays for analysis of gene expression and electrophoretic mobility shift assays for determination of DNA-binding activity of transcription factors were used.

RESULTS

The doxorubicin-resistant lung cancer cell subline (SK-MES-1/DX1000), selected from SK-MES-1/WT cells, upregulated MDR1 expression, thereby showing MDR phenotypes. PSC833 sensitized SK-MES-1/DX1000 cells to doxorubicin. PSC833 (5 microM) also decreased the intracellular accumulation of fluorescent Pgp substrates such as rhodamine 123 and daunorubicin in SK-MES-1/DX1000 cells. PSC833 downregulated MDR1 mRNA and Pgp expression in a time- and concentration-dependent manner. PSC833 activated c-Jun NH2-terminal kinase (JNK)/c-Jun and enhanced AP-1 DNA-binding activity, but suppressed nuclear translocation of NF-kappaB, all of which were prevented by pretreatment with a JNK inhibitor SP600125.

CONCLUSIONS

These results indicate that PSC833 not only sensitizes SK-MES-1/DX1000 cells to doxorubicin by enhancing drug accumulation, but also downregulates MDR1 expression by activating JNK/c-Jun/AP-1 and suppressing NF-kappaB.

Anti-inflammatory effect of leaves of Eriobotrya japonica correlating with attenuation of p38 MAPK, ERK, and NF-kappaB activation in mast cells

Mast cell-mediated allergic inflammation is involved in many diseases such as asthma and sinusitis. Mast cells induce synthesis and production of pro-inflammatory cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8 with immune regulatory properties. In the present study, we investigate the effect an unspecified aqueous extract from leaves of Eriobotrya japonica Lindl. (Rosaceae) (LEJL) on the expression of pro-inflammatory cytokines and its possible mechanisms of action in human mast cells (HMC-1). LEJL dose-dependently inhibited phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187 (PMACI)-induced gene expression and secretion of TNF-alpha, IL-6, and IL-8. LEJL attenuated PMACI-induced activation of nuclear factor (NF)-kappaB, and specifically blocked activation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) but not that of c-jun N-terminal kinase. The inhibitory effect of LEJL on the pro-inflammatory cytokines was likely NF-kappaB, p38 MAPK, and ERK dependent. Our in vitro studies provide evidence that LEJL might contribute to the treatment of mast cell-derived allergic inflammatory diseases.

Discoidin domain receptor 2 mediates the collagen II-dependent release of interleukin-6 in primary human chondrocytes

We deciphered constituent parts of a signal transduction cascade that is initiated by collagen II and results in the release of various pro-inflammatory cytokines, including interleukin-6 (IL-6), in primary human chondrocytes. This cascade represents a feed-forward mechanism whereby cartilage matrix degradation is exacerbated by the mutually inducing effect of released collagen II fragments and pro-inflammatory cytokines. We previously proposed discoidin domain receptor 2 as a central mediator in this event. Since this cascade plays a prominent role in the pathogenesis of osteoarthritis, our study further investigates the hypothesis that discoidin domain receptor 2 is a candidate receptor for collagen II, and that transcription factor NFkappaB, lipid kinase PI3K, and the MAP kinases are constituent parts of this very signal transduction cascade. To accomplish this, we selectively knocked down the molecules of interest in primary human chondrocytes, induced the specified cascade by incubating primary human chondrocytes with collagen II, and observed the outcome, specifically the changes in interleukin-6 release. Knockdown was performed by siRNA-mediated gene silencing in the case of discoidin domain receptor 2 (DDR2) or by using specific inhibitors for the remainder of the molecules. Results indicated that discoidin domain receptor 2 mediates the collagen II-dependent release of interleukin-6 in primary human chondrocytes and that MAP kinases p38, JNK and ERK, as well as transcription factor NFkappaB, are integral components of intracellular collagen II signalling. Given the detrimental role of these molecules in osteoarthritis, our findings provide new targets for more specific therapeutics, which may have fewer side effects than those currently applied.

The collagen receptor DDR1 regulates cell spreading and motility by associating with myosin IIA

The spreading and migration of cells on adhesive substrates is regulated by the counterbalance of contractile and protrusive forces. Non-muscle myosin IIA, an ubiquitously expressed contractile protein and enzyme, is implicated in the regulation of cell spreading and directional migration in response to various stimuli. Here we show that discoidin domain receptor 1 (DDR1), a tyrosine kinase receptor activated by type I collagen, associates with the non-muscle myosin IIA heavy chain (NMHC-IIA) upon ligand stimulation. An association was also indicated by coimmunoprecipitation of NMHC-IIA with full-length DDR1, but not with the truncated DDR1d-isoform lacking the kinase domain. DDR1 was important for assembly of NMHC-IIA into filaments on cells plated on collagen. DDR1 expression inhibited cell spreading over collagen but promoted cell migration. By contrast, blockade of non-muscle myosin II activity by blebbistatin enhanced cell spreading but inhibited migration over collagen. We propose that myosin and DDR1 impact cell spreading and migration by regulating adhesive contacts with collagen.

Collagens in the progression and complications of atherosclerosis

Collagens constitute a major portion of the extracellular matrix in the atherosclerotic plaque, where they contribute to the strength and integrity of the fibrous cap, and also modulate cellular responses via specific receptors and signaling pathways. This review focuses on the diverse roles that collagens play in atherosclerosis; regulating the infiltration and differentiation of smooth muscle cells and macrophages; controlling matrix remodeling through feedback signaling to proteinases; and influencing the development of atherosclerotic complications such as plaque rupture, aneurysm formation and calcification. Expanding our understanding of the pathways involved in cell-matrix interactions will provide new therapeutic targets and strategies for the diagnosis and treatment of atherosclerosis.

Anti-allergic effects of Teucrium japonicum on mast cell-mediated allergy model

The mast cell-mediated immediate-type allergic reaction is involved in many allergic diseases such as asthma, allergic rhinitis, and sinusitis. Stimulation of mast cells starts the process of degranulation resulting in release of mediators such as histamine and an array of inflammatory cytokines. In this report, we investigated the effect of aqueous extract of Teucrium japonicum Houttuyn (Labiatae) (AXTJ) on the mast cell-mediated allergy model and studied its possible mechanisms of action. AXTJ inhibited compound 48/80-induced systemic reactions and serum histamine release in mice. AXTJ decreased immunoglobulin E-mediated passive cutaneous anaphylaxis reaction. AXTJ reduced histamine release and intracellular calcium from rat peritoneal mast cells activated by compound 48/80. In addition, AXTJ attenuated activation of nuclear factor (NF)-kappaB, and downstream tumor necrosis factor (TNF)-alpha expression in phorbol 12-myristate 13-acetate and calcium ionophore A23187-stimulated human mast cells. Our findings provide evidence that AXTJ inhibits mast cell-derived allergic reactions and involvement of intracellular calcium, TNF-alpha, and NF-kappaB in these effects.

Flavonoids inhibit histamine release and expression of proinflammatory cytokines in mast cells

Mast cells participate in allergy and inflammation by secreting inflammatory mediators such as histamine and proinflammatory cytokines. Flavonoids are naturally occurring molecules with antioxidant, cytoprotective, and antiinflammatory actions. However, effect of flavonoids on the release of histamine and proinflammatory mediator, and their comparative mechanism of action in mast cells were not well defined. Here, we compared the effect of six flavonoids (astragalin, fisetin, kaempferol, myricetin, quercetin, and rutin) on the mast cell-mediated allergic inflammation. Fisetin, kaempferol, myricetin, quercetin, and rutin inhibited IgE or phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-mediated histamine release in RBL-2H3 cells. These five flavonoids also inhibited elevation of intracellular calcium. Gene expressions and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-8 were assessed in PMACI-stimulated human mast cells (HMC-1). Fisetin, quercetin, and rutin decreased gene expression and production of all the proinflammatory cytokines after PMACI stimulation. Myricetin attenuated TNF-alpha and IL-6 but not IL-1beta and IL-8. Fisetin, myricetin, and rutin suppressed activation of NF-kappaB indicated by inhibition of nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. The pharmacological actions of these flavonoids suggest their potential activity for treatment of allergic inflammatory diseases through the down-regulation of mast cell activation.