Blockage of HSP 90 modulates Helicobacter pylori-induced IL-8 productions through the inactivation of transcriptional factors of AP-1 and NF-kappaB

Inhibition of Hsp90 Counteracts the Established Experimental Dermal Fibrosis Induced by Bleomycin

Our previous study demonstrated that heat shock protein 90 (Hsp90) is overexpressed in the involved skin of patients with systemic sclerosis (SSc) and in experimental dermal fibrosis. Pharmacological inhibition of Hsp90 prevented the stimulatory effects of transforming growth factor-beta on collagen synthesis and the development of dermal fibrosis in three preclinical models of SSc. In the next step of the preclinical analysis, herein, we aimed to evaluate the efficacy of an Hsp90 inhibitor, 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), in the treatment of established experimental dermal fibrosis induced by bleomycin. Treatment with 17-DMAG demonstrated potent antifibrotic and anti-inflammatory properties: it decreased dermal thickening, collagen content, myofibroblast count, expression of transforming growth factor beta receptors, and pSmad3-positive cell counts, as well as leukocyte infiltration and systemic levels of crucial cytokines/chemokines involved in the pathogenesis of SSc, compared to vehicle-treated mice. 17-DMAG effectively prevented further progression and may induce regression of established bleomycin-induced dermal fibrosis to an extent comparable to nintedanib. These findings provide further evidence of the vital role of Hsp90 in the pathophysiology of SSc and characterize it as a potential target for the treatment of fibrosis with translational implications due to the availability of several Hsp90 inhibitors in clinical trials for other indications.

Helicobacter pylori-downregulated tumor necrosis factor receptor-associated protein 1 mediates apoptosis of human gastric epithelial cells

Heat shock proteins (HSPs) are crucial proteins in maintaining the homeostasis of human gastric epithelial cells. Tumor necrosis factor receptor-associated protein 1 (TRAP1), a member of the HSP90 family, has been shown to be involved in various crucial physiological processes, particularly against apoptosis. However, the regulation and function of TRAP1 in Helicobacter pylori infection is still unknown. Here, we found that TRAP1 expression was downregulated on human gastric epithelial cells during H. pylori infection by real-time polymerase chain reaction (PCR) and western blot analysis. Through virulence factors mutant H. pylori strains infection and inhibitors screening, we found that H. pylori vacuolating cytotoxin A ( vacA), but not cytotoxin-associated gene A ( cagA) protein, induced human gastric epithelial cells to downregulate TRAP1 via P38MAPK pathway by real-time PCR and western blot analysis. Furthermore, downregulation of TRAP1 with lentivirus carrying TRAP1 short hairpin RNA constructs impairs mitochondrial function, and increases apoptosis of gastric epithelial cells. The results indicate that H. pylori vacA downregulated TRAP1 is involved in the regulation of gastric epithelial cell apoptosis.

Nickel ions bind to HSP90β and enhance HIF-1α-mediated IL-8 expression

Nickel ions (Ni²⁺) eluted from biomedical devices cause inflammation and Ni allergy. Although Ni²⁺ and Co²⁺ elicit common effects, Ni²⁺ induces a generally stronger inflammatory reaction. However, the molecular mechanism by which Ni²⁺ and Co²⁺ induce such different responses remains to be elucidated. In the present study, we compared the effects of Ni²⁺ and Co²⁺ on the expression of interleukin (IL)-8 in human monocyte THP-1 cells. We report that NiCl₂ but not CoCl₂ induced the expression of IL-8; in contrast, CoCl₂ elicited a higher expression of hypoxia-inducible factor-1α (HIF-1α). The NiCl₂-induced expression of IL-8 in late phase was blocked by a HIF-1α inhibitor, PX-478, indicating that NiCl₂ targets additional factors responsible for activating HIF-1α. To identify such targets, proteins that bound preferentially to Ni-NTA beads were analyzed by LC/MS/MS. The analysis yielded heat shock protein 90β (HSP90β) as a possible candidate. Furthermore, Ni²⁺ reduced the interaction of HSP90β with HIF-1α, and instead promoted the interaction between HIF-1α and HIF-1β, as well as the nuclear localization of HIF-1α. Using various deletion variants, we showed that Ni²⁺ could bind to the linker domain on HSP90β. These results suggest that HSP90β plays important roles in Ni²⁺-induced production of IL-8 and could be a potential target for the regulation of Ni²⁺-induced inflammation.

Dexamethasone inhibits inflammatory response via down regulation of AP-1 transcription factor in human lung epithelial cells

The production of inflammatory mediators by epithelial cells in inflammatory lung diseases may represent an important target for the anti-inflammatory effects of glucocorticoids. Activator protein-1 is a major activator of inflammatory genes and has been proposed as a target for inhibition by glucocorticoids. We have used human pulmonary type-II A549 cells to examine the effect of dexamethasone on the phorbol ester (PMA)/Lipopolysaccharide (LPS) induced pro-inflammatory cytokines and AP-1 factors. A549 cells were treated with and without PMA or LPS or dexamethasone and the cell viability and nitric oxide production was measured by MTT assay and Griess reagent respectively. Expression of pro-inflammatory cytokines and AP-1 factors mRNA were measured using semi quantitative RT-PCR. The PMA/LPS treated cells show significant 2-3 fold increase in the mRNA levels of pro-inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8 and TNF-α), cyclo‑oxygenase-2 (COX-2) and specific AP-1 factors (c-Jun, c-Fos and Jun-D). Whereas, pretreatment of cells with dexamethasone significantly inhibited the LPS induced nitric oxide production and PMA/LPS induced mRNAs expression of above pro-inflammatory cytokines, COX-2 and AP-1 factors. Cells treated with dexamethasone alone at both the concentrations inhibit the mRNAs expression of IL-1β, IL-6 and TNF-α compared to control. Our study reveals that dexamethasone decreased the mRNAs expression of c-Jun and c-Fos available for AP-1 formation suggested that AP-1 is the probable key transcription factor involved in the anti-inflammatory activity of dexamethasone. This may be an important molecular mechanism of steroid action in asthma and other chronic inflammatory lung diseases which may be useful for treatment of lung inflammatory diseases.

Serum and Mucosal Cytokine Profiles in Patients with Active Helicobacter Pylori and Ischemic Heart Disease: Is There a Relationship?

This study is designed to investigate, for the first time, circulating and gastric mucosal levels of IL1-α, IL-6, IL-8 and TNF-α in patients with ischemic heart disease (IHD) and matched controls, according to the presence or absence of active Helicobacter pylori infection. Furthermore, in order to evaluate whether modified lipid profile was associated to an increased cardiovascular risk, this was determined in the same groups. Cytokine levels were measured using ELISA in 58 patients with IHD and 52 controls. Active H. pylori infection was assessed if either culture of H. pylori or rapid urease test gave a positive result. Our findings indicate increasing cytokine mucosal levels in H. pylori-positive patients compared to H. pylori-negative subjects. However, the increase was statistically significant only for IL-6 and TNF-α in the gastric mucosa of IHD patients. In H. pylori-positive controls, IL-8 mucosal levels positively correlated with both IL-1α (r = 0.98; P = 0.0003) and IL-6 (r = 0.83; P = 0.03) levels. Circulating cytokine levels were comparable in IHD and healthy subjects, regardless of H. pylori status. There were no correlations between mucosal and circulating cytokine levels. Active H. pylori infection was not associated with a modified lipid profile in either controls or IHD patients, although ApoAI levels were significantly higher in H. fly/ort'-positive controls compared to those H. pylori-negative. Taken together, the results of the present study provide evidence that active H. pylori infection may play a role as a trigger factor in the pathophysiology of IHD by inducing an inflammatory cascade concentrated on gastric mucosa.

A systems pharmacology approach to investigate the mechanisms of action of Semen Strychni and Tripterygium wilfordii Hook F for treatment of rheumatoid arthritis

ETHNOPHARMACOLOGY RELEVANCE

The angiogenesis control at the initiation of rheumatoid arthritis (RA) that mainly blocks the inflammatory cascades expects to attenuate the action of angiogenic mediators, synovial angiogenesis, and to partially reverse the erosive bone damage. Two typical Chinese herbs, Semen Strychni and Tripterygium wilfordii Hook F (TwHF) have been used as a remedy to treat RA since ancient time. However, their functioning mechanisms are still unknown. Thus it is necessary to exploit their underlying mechanism for the treatment of RA.

METHODS

This study was undertaken to analyze their underlying mechanism based on a systems biology platform. Firstly, active components of the two herbs were screened out from TcmSP database based on their OB and DL values. Then their potential targets were predicted by using Random Forest, Support Vector Machine, and validated via docking process. Finally, a network of compound-target was constructed.

RESULTS

In this work, 27 and 33 active compounds were screened out from Semen Strychni and TwHF, targeting 28 and 32 potential proteins, respectively. The results show that the two herbs modulate the angiogenesis mediators through both direct and indirect pathways, and 21 common targets shared by Semen Strychni and TwHF bear major responsibility for treating RA.

CONCLUSIONS

The underlying mechanism of Semen Strychni and TwHF in treatment of RA is through multiple targets interaction by their blocking of the angiogenesis mediator cascades. This may provide us a better understanding of the function of the two herbs for the treatment of RA, as well as a clue to unveil their possible treatment effects of other systemic diseases, and in this way, hopefully the screening models may facilitate the discovery of novel combined drugs.

Targeting heat-shock protein 90 with ganetespib for molecularly targeted therapy of gastric cancer

Gastric cancer (GC) remains the fifth most common cancer worldwide. Heat-shock protein 90 (HSP90) has become an attractive therapeutic target in treating cancers, because of its abnormally high expression in cancers. Several successful cases of HSP90 inhibitors capable of inhibiting GC inspired us to try ganetespib, a clinically promising and actively investigated second-generation HSP90 inhibitor in GC treatment. In our study, we show that ganetespib markedly reduced the growth of MGC-803 and also significantly inhibited the growth of SGC-7901 and MKN-28 in a dose-dependent manner. It induced G2/M cell-cycle arrest and apoptosis in all three cell lines, together with the related markers affected significantly. Mechanistically, ganetespib caused pronounced decrease of expression of classic HSP90 client proteins. Specifically, it greatly affected epidermal growth factor receptor (EGFR) signaling cascades by markedly decreasing the levels of total EGFR and EGFR on cell membranes. EGFR knockdown also induced cell-cycle arrest and apoptosis accompanied with a decrease of several EGFR downstream proteins. These results strongly support that EGFR signaling greatly contributes to the ganetespib inhibitory effects. Besides, we found that the responses of GC cell lines to ganetespib correlated well with their EGFR expression levels: MGC-803, as well as AGS and BGC-803, with higher EGFR expression responded to ganetespib better, whereas SGC-7901 and MKN-28 with lower EGFR levels were much less sensitive to ganetespib. Although SGC-7901 and MKN-28 were not very sensitive to ganetespib, ganetespib worked synergistically with radiation and cisplatin in killing them. Importantly, ganetespib significantly inhibited the growth of xenograft tumors in vivo as a single agent or in combination with cisplatin. Results of hematoxylin/eosin staining, TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) assays, and immunohistochemistry staining of phosphorylated cyclin-dependent kinase 1 (pCDK1), EGFR and Ki-67 revealed significant differences in ganetespib-treated tumors. Collectively, our data suggest that ganetespib, as a new potent treatment option, can be used for the molecularly targeted therapy of GC patients according to their expression profiles of EGFR.

Hsp90 blockade modulates bullous pemphigoid IgG-induced IL-8 production by keratinocytes

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering skin disease characterized by autoantibodies against the hemidesmosomal proteins BP180 and BP230. The cell stress chaperone heat shock protein 90 (Hsp90) has been implicated in inflammatory responses, and recent evidence suggests that it represents a novel treatment target in autoimmune bullous diseases. The aim of the study was to investigate the contribution of Hsp90 to the proinflammatory cytokine production in keratinocytes induced by autoantibodies to BP180 from BP patient serum. HaCaT cells were treated with purified human BP or normal IgG in the absence or presence of the Hsp90 blocker 17-DMAG and effects on viability, interleukin 6 (IL-6) and IL-8 (cytokines critical for BP pathology), NFκB (their major transcription factor), and Hsp70 (marker of effective Hsp90 inhibition and potent negative regulator of inflammatory responses) were investigated. We found that BP IgG stimulated IL-6 and IL-8 release from HaCaT cells and that non-toxic doses of 17-DMAG inhibited this IL-8, but not IL-6 secretion in a dose- and time-dependent fashion. Inhibition of this IL-8 production was also observed at the transcriptional level. In addition, 17-DMAG treatment blunted BP IgG-mediated upregulation of NFκB activity and was associated with Hsp70 induction. This study provides important insights that Hsp90 is involved as crucial regulator in anti-BP180 IgG-induced production of keratinocyte-derived IL-8. By adding to the knowledge of the multimodal anti-inflammatory effects of Hsp90 blockade, our data further support the introduction of Hsp90 inhibitors into the clinical setting for treatment of autoimmune diseases, especially for BP.

Novel mechanism of attenuation of LPS-induced NF-κB activation by the heat shock protein 90 inhibitor, 17-N-allylamino-17-demethoxygeldanamycin, in human lung microvascular endothelial cells

Heat shock protein (hsp) 90 inhibition attenuates NF-κB activation and blocks inflammation. However, the precise mechanism of NF-κB regulation by hsp90 in the endothelium is not clear. We investigated the mechanisms of hsp90 inhibition by 17-N-allylamino-17-demethoxygeldanamycin (17-AAG) on NF-κB activation by LPS in primary human lung microvascular endothelial cells. Transcriptional activation of NF-κB was measured by luciferase reporter assay, gene expression by real-time RT-PCR, DNA binding of transcription factors by chromatin immunoprecipitation assay, protein-protein interaction by coimmunoprecipitation/immunoblotting, histone deacetylase (HDAC)/histone acetyltransferase enzyme activity by fluorometry, and nucleosome eviction by partial microccocal DNase digestion. In human lung microvascular endothelial cells, 17-AAG-induced degradation of IKBα was accomplished regardless of the phosphorylation/ubiquitination state of the protein. Hence, 17-AAG did not block LPS-induced NF-κB nuclear translocation and DNA binding activity. Instead, 17-AAG blocked the recruitment of the coactivator, cAMP response element binding protein binding protein, and prevented the assembly of a transcriptionally competent RNA polymerase II complex at the κB elements of the IKBα (an NF-κB-responsive gene) promoter. The effect of LPS on IKBα mRNA expression was associated with rapid deacetylation of histone-H3(Lys9) and a dramatic down-regulation of core histone H3 binding. Even though treatment with an HDAC inhibitor produced the same effect as hsp90 inhibition, the effect of 17-AAG was independent of HDAC. We conclude that hsp90 inhibition attenuates NF-κB transcriptional activation by preventing coactivator recruitment and nucleosome eviction from the target promoter in human lung endothelial cells.

Anti-inflammatory properties of gastric-derived Lactobacillus plantarum XB7 in the context of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori colonization of the gastric epithelium induces interleukin-8 (IL-8) production and inflammation leading to host cell damage. We searched for gastric-derived Lactobacillus with the ability to suppress H. pylori-induced inflammation.

MATERIALS AND METHODS

Conditioned media from gastric-derived Lactobacillus spp. were tested for the ability to suppress H. pylori-induced IL-8 production in AGS gastric epithelial cells. IL-8 protein and mRNA levels were measured by ELISA and qPCR, respectively. The changes on host cell signaling pathway were analyzed by Western blotting and the anti-inflammatory effect was tested in a Sprague-Dawley rat model.

RESULTS

Conditioned media from L. salivarius B101, L. rhamnosus B103, and L. plantarum XB7 suppressed IL-8 production and IL-8 mRNA expression in H. pylori-induced AGS cells without inhibiting H. pylori growth. Conditioned media from LS-B101, LR-B103, and LP-XB7 suppressed the activation of NF-κB in AGS cells, while strain LP-XB7 also suppressed c-Jun activation. The anti-inflammatory effect of LP-XB7 was further assessed in vivo using a H. pylori-infected Sprague-Dawley rat model. Strain LP-XB7 contributed to a delay in the detection and colonization of H. pylori in rat stomachs, attenuated gastric inflammation, and ameliorated gastric histopathology. Additionally, the administration of LP-XB7 correlated with the suppression of TNF-α and CINC-1 in sera, and suppression of CINC-1 in the gastric mucosa of H. pylori-infected rats.

CONCLUSIONS

These results suggest that L. plantarum XB7 produces secreted factors capable of modulating inflammation during H. pylori infection, and this probiotic Lactobacillus strain shows promise as an adjunctive therapy for treating H. pylori-associated disease.

Helicobacter pylori and interleukin-8 in gastric cancer

Helicobacter pylori (H. pylori) is a major etiological factor in the development of gastric cancer. Large-scale epidemiological studies have confirmed the strong association between H. pylori infection and both cancer development and progression. Interleukin-8 (IL-8) is overexpressed in gastric mucosa exposed to H. pylori. The expression of IL-8 directly correlates with a poor prognosis in gastric cancer. IL-8 is multifunctional. In addition to its potent chemotactic activity, it can induce proliferation and migration of cancer cells. In this review, we focus on recent insights into the mechanisms of IL-8 signaling associated with gastric cancer. The relationship between IL-8 and H. pylori is discussed. We also summarize the current therapeutics against IL-8 in gastric cancer.

Aberrant expression and secretion of heat shock protein 90 in patients with bullous pemphigoid

The cell stress chaperone heat shock protein 90 (Hsp90) has been implicated in inflammatory responses and its inhibition has proven successful in different mouse models of autoimmune diseases, including epidermolysis bullosa acquisita. Here, we investigated expression levels and secretory responses of Hsp90 in patients with bullous pemphigoid (BP), the most common subepidermal autoimmune blistering skin disease. In comparison to healthy controls, the following observations were made: (i) Hsp90 was highly expressed in the skin of BP patients, whereas its serum levels were decreased and inversely associated with IgG autoantibody levels against the NC16A immunodominant region of the BP180 autoantigen, (ii) in contrast, neither aberrant levels of circulating Hsp90 nor any correlation of this protein with serum autoantibodies was found in a control cohort of autoimmune bullous disease patients with pemphigus vulgaris, (iii) Hsp90 was highly expressed in and restrictedly released from peripheral blood mononuclear cells of BP patients, and (iv) Hsp90 was potently induced in and restrictedly secreted from human keratinocyte (HaCaT) cells by BP serum and isolated anti-BP180 NC16A IgG autoantibodies, respectively. Our results reveal an upregulated Hsp90 expression at the site of inflammation and an autoantibody-mediated dysregulation of the intracellular and extracellular distribution of this chaperone in BP patients. These findings suggest that Hsp90 may play a pathophysiological role and represent a novel potential treatment target in BP.

Transcription factor complex AP-1 mediates inflammation initiated by Chlamydia pneumoniae infection

Chlamydia pneumoniae is responsible for a high prevalence of respiratory infections worldwide and has been implicated in atherosclerosis. Inflammation is regulated by transcription factor (TF) networks. Yet, the core TF network triggered by chlamydiae remains largely unknown. Primary human coronary artery endothelial cells were mock-infected or infected with C. pneumoniae to generate human transcriptome data throughout the chlamydial developmental cycle. Using systems network analysis, the predominant TF network involved receptor, binding and adhesion and immune response complexes. Cells transfected with interfering RNA against activator protein-1 (AP-1) members FOS, FOSB, JUN and JUNB had significantly decreased expression and protein levels of inflammatory mediators interleukin (IL)6, IL8, CD38 and tumour necrosis factor compared with controls. These mediators have been shown to be associated with C. pneumoniae disease. Expression of AP-1 components was regulated by MAPK3K8, a MAPK pathway component. Additionally, knock-down of JUN and FOS showed significantly decreased expression of Toll-like receptor (TLR)3 during infection, implicating JUN and FOS in TLR3 regulation. TLR3 stimulation led to elevated IL8. These findings suggest that C. pneumoniae initiates signalling via TLR3 and MAPK that activate AP-1, a known immune activator in other bacteria not previously shown for chlamydiae, triggering inflammation linked to C. pneumoniae disease.

Helicobacter pylori induces promoter hypermethylation and downregulates gene expression of IRX1 transcription factor on human gastric mucosa

BACKGROUND AND AIM

Gene silence of IRX1 tumor suppressor by promoter CpG methylation combined with loss of heterozygosity (LOH) has been identified in human gastric cancer. This study investigated the association between methylation of IRX1 and Helicobacter pylori infection in gastric mucosa tissues and cell line.

METHODS

IRX1 methylation was studied by methylation specific polymerase chain reaction (MSP) and bisulfate sequencing polymerase chain reaction (BSP) methods in gastric mucosa tissues from H. pylori-positive chronic gastritis patients or H. pylori-negative chronic gastritis patients. Promoter activity, methylation status and gene expressing level of IRX1 were evaluated by persistent infecting H. pylori on human gastric cells GES-1 in vitro. Electron microscopy was used to observe the effect of H. pylori infection on GES-1 gastric mucosa cells.

RESULTS

The methylation level of IRX1 promoter in H. pylori positive chronic gastritis and H. pylori negative chronic gastritis was 55.30%±13.17 versus 5.20%±6.31, respectively (P<0.01). H. pylori infection stimulated increased microvillus, and mucous secretion on GES-1 cells. Infection of H. pylori induced IRX1 promoter methylation and downregulation of the promoter activity as well as gene expression significantly.

CONCLUSIONS

This study firstly demonstrated that H. pylori infection contributes to IRX1 promoter methylation on gastric mucosa.

A mechanism for the action of the compound DA-6034 on NF-κB pathway activation in Helicobacter pylori-infected gastric epithelial cells

DA-6034 is a synthetic derivative of eupatilin, a flavonoid with anti-inflammatory effects. The aim of this study was to investigate the effects of DA-6034 on the interactions between IκB kinase (IKK) and heat shock protein 90 (Hsp90), and activation of the nuclear factor-kappaB (NF-κB) signalling pathway in human gastric epithelial cells infected with Helicobacter pylori. MKN-45 gastric epithelial cell line was treated with DA-6034 and H. pylori. DA-6034 significantly inhibited NF-κB activation and upregulated the expressions of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 in MKN-45 cells infected with H. pylori. However, DA-6034 did not influence activator protein-1 DNA binding activity in H. pylori-infected gastric epithelial cells. Pretreatment with DA-6034 attenuated the H. pylori-induced increase in IKK activity, and Hsp90 was associated with IKK-α and IKK-γ in MKN-45 cells. Treatment with DA-6034 dissociated the Hsp90 and IKK-γ complex in H. pylori-infected cells, leading to the inhibition of IL-8 expression. These results suggest that the eupatilin derivative 7-carboxymethyloxy-3',4',5-trimethoxy flavone has anti-inflammatory activity in gastric epithelial cells infected with H. pylori through the promotion of the dissociation of the IKK-γ-Hsp90 complex and suppression of NF-κB signalling.

Heat shock protein: hard worker or bad offender for gastric diseases

Heat shock proteins (HSPs) have core housekeeping functions in the cells where they are built-in components of folding, signal transduction pathways, and quality control functions for which they proofread the structure of proteins and repair misfolded conformers. Helicobacter pylori (H. pylori) infection leads to significant inflammations in the gastric mucosa, which is closely associated with development of either precancerous lesion including chronic atrophic gastritis or gastric cancer in addition to, peptic ulcer disease, and mucosa-associated lymphoid tissue (MALT) lymphoma. Therefore, the association between H. pylori infection and role of HSP has been focused as an important issue because there had been rather conflicting publications showing that HSPs as a good worker for defense against H. pylori infection, whereas HSPs as a bad offender contributing to the progression of H. pylori-associated gastric carcinogenesis in addition to aggravation of gastric inflammation. In this paper regarding proteomic discovery of HSPs related to H. pylori-associated gastric diseases, we introduce several evidences obtained from proteomic analysis dealing with friend or foe role of HSP in H. pylori infection from a cellular level to human diseases. The implication of HSPs in alcoholic or NSAIDs-induced gastritis and the intervening of HSPs in biological changes exemplified with TGF-β signaling, key tumor suppressor growth factors regulating inflammation, immune function, and carcinogenesis were further introduced.

Regulators of endothelial and epithelial barrier integrity and function in acute lung injury

Permeability edema is a life-threatening complication accompanying acute lung injury (ALI), severe pneumonia and the acute respiratory distress syndrome (ARDS), which can be associated with a reduced alveolar liquid clearance (ALC) capacity, a disruption of the alveolar epithelial barrier, and an increased capillary endothelial permeability. Bacterial and viral infections can directly promote pulmonary endothelial hyperpermeability and indirectly decrease the function and/or expression of ion transporters regulating ALC in type II alveolar epithelial cells, by means of inducing a strong inflammatory and oxidative stress response in the infected lungs. Apart from ventilation strategies, no standard treatment exists for permeability edema, making the search for novel regulators of endothelial and epithelial hyperpermeability and dysfunction important. Here, we present an overview of recently identified substances that inhibit and/or reverse endothelial barrier disruption and permeability or alveolar epithelial dysfunction: (1) zinc chelators, which were shown to attenuate the effects of oxidative stress on the pulmonary endothelium; (2) peroxisome proliferator activated receptor (PPAR) ligands, which have been shown to exert anti-inflammatory effects, by decreasing the expression of pro-inflammatory genes; (3) extracellular ATP, produced during inflammation, which induces a rapid and dose-dependent increase in transendothelial electrical resistance (TER) across pulmonary endothelial cells; (4) the lectin-like domain of TNF, which is spatially distinct from the receptor binding sites and which protects from hydrostatic and permeability edema and (5) Hsp90 inhibitors, which prevent and repair toxin-induced hyperpermeability. Unraveling the mechanism of action of these agents could contribute to the development of novel therapeutic strategies to combat permeability edema.

Conjugated linoleic acids produced by Lactobacillus dissociates IKK-gamma and Hsp90 complex in Helicobacter pylori-infected gastric epithelial cells

Although probiotics have been reported to reduce the gastric inflammatory response to Helicobacter pylori infection, little information is available regarding the molecular mechanisms behind this reduction. This study investigates the role of conjugated linoleic acids (CLA) produced by probiotics in interactions of IkappaB kinase (IKK) and heat shock protein 90 (Hsp90) to activate the nuclear factor-kappaB (NF-kappaB) signaling pathway in human gastric epithelial cells infected with H. pylori. Conditioned medium (CM) containing Lactobacillus acidophilus-producing CLA significantly inhibited the activated NF-kappaB signals and the upregulated expression of interleukin-8 (IL-8) in MKN-45 cells infected with H. pylori. Pretreatment with CM with CLA attenuated the increased IKK activity induced by H. pylori. Transfection of siRNA for IKK-beta dramatically reduced H. pylori-induced IkappaBalpha phosphorylation, but siRNA for IKK-alpha had little effect on IkappaBalpha phosphorylation, although the siRNA for IKK-alpha significantly decreased IL-8 production. Furthermore, Hsp90 was associated with IKK-alpha and IKK-gamma in H. pylori-infected cells, and CM with CLA dissociated the complex between Hsp90 and IKK-gamma. These results suggest that CLA produced by probiotics has anti-inflammatory activity in gastric epithelial cells infected with H. pylori via dissociation of the IKK-gamma and Hsp90 complex.

Heat shock protein 90 inhibitors attenuate LPS-induced endothelial hyperpermeability

Endothelial hyperperme ability leading to vascular leak is an important consequence of sepsis and sepsis-induced lung injury. We previously reported that heat shock protein (hsp) 90 inhibitor pretreatment improved pulmonary barrier dysfunction in a murine model of sepsis-induced lung injury. We now examine the effects of hsp90 inhibitors on LPS-mediated endothelial hyperpermeability, as reflected in changes in transendothelial electrical resistance (TER) of bovine pulmonary arterial endothelial cells (BPAEC). Vehicle-pretreated cells exposed to endotoxin exhibited a concentration-dependent decrease in TER, activation of pp60(Src), phosphorylation of the focal adhesion protein paxillin, and reduced expression of the adherens junction proteins, vascular endothelial (VE)-cadherin and beta-catenin. Pretreatment with the hsp90 inhibitor, radicicol, prevented the decrease in TER, maintained VE-cadherin and beta-catenin expression, and inhibited activation of pp60(Src) and phosphorylation of paxillin. Similarly, when BPAEC hyperpermeability was induced by endotoxin-activated neutrophils, pretreatment of neutrophils and/or endothelial cells with radicicol protected against the activated neutrophil-induced decrease in TER. Increased paxillin phosphorylation and decreased expression of beta-catenin and VE-cadherin were also observed in mouse lungs 12 h after intraperitoneal endotoxin and attenuated in mice pretreated with radicicol. These results suggest that hsp90 plays an important role in sepsis-associated endothelial barrier dysfunction.

Predictive role of nuclear factor-kappaB activity in gastric cancer: a promising adjuvant approach with caffeic acid phenethyl ester

BACKGROUND

The biologic significance of nuclear factor-kappaB (NF-kappaB) activation in human gastric cancer is unclear. We clarify the clinical significance of NF-kappaB activation and its relationship to Helicobacter pylori infection, a well-known pathogenesis of gastric cancer. Moreover, we examine the effects and underlying mechanisms induced by caffeic acid phenethyl ester (CAPE), an inhibitor of NF-kappaB, for gastric carcinoma.

METHODS

NF-kappaB was located immunohistochemically in 90 human gastric cancer specimens and 50 nonmalignant gastric specimens. The correlations between NF-kappaB activation, pathologic staging, and H. pylori infection were analyzed. We also performed electrophoretic mobility gel shift assay, real-time reverse transcription polymerase chain reaction, and enzyme-linked immunosorbent assay to evaluate the responses of AGS (a gastric adenocarcinoma epithelial cell line) human gastric cancer cells subsequent to H. pylori infection or CAPE treatment.

RESULTS

Nuclear expression of NF-kappaB was significantly more frequently observed in gastric cancer tissues than in nonmalignant gastric tissues (31% vs. 4%, P=0.0001). The activity of NF-kappaB and the expressions of MMP-9, IL-1beta, and IL-8 in AGS cells were activated by H. pylori infection. However, the augmented responses could be significantly reversed by CAPE treatment. Moreover, in vitro studies showed that CAPE inhibits tumor growth and capacity for invasion.

CONCLUSIONS

NF-kappaB activation is related to carcinogenesis, tumor aggression, and H. pylori infection with the increased expression of MMP-9, IL-1beta, and IL-8. Moreover, NF-kappaB inhibitors or anti-inflammatory agents such as CAPE might be new adjuvant agent against invasive gastric carcinoma.

Helicobacter pylori induces CCL20 expression

CCL20 attracts immature dendritic cells and memory T cells and plays a role on mucosal surfaces in inflammation. However, whether Helicobacter pylori infection induces CCL20 in human gastric epithelial cells remains to be determined. The aim of this study was to analyze the molecular mechanism of H. pylori-induced CCL20 expression. Expression of CCL20 mRNA was assessed by reverse transcription-PCR. Five normal and five H. pylori-infected gastric tissue samples were stained immunohistochemically for CCL20. A luciferase assay was used to monitor activation of the CCL20 gene promoter, and an electrophoretic mobility shift assay was used to explore the binding of transcription factors to this promoter. The CCL20 expression in epithelial cells of H. pylori-positive tissues was higher than that in H. pylori-negative tissues. H. pylori induced CCL20 expression in gastric epithelial cell lines, and the induction was dependent on an intact cag pathogenicity island. Activation of the CCL20 promoter by H. pylori occurred through the action of NF-kappaB. Transfection of IkappaB kinase and NF-kappaB-inducing kinase dominant negative mutants inhibited H. pylori-mediated activation of CCL20. Treatment with an inhibitor of Hsp90 suppressed H. pylori-induced CCL20 mRNA due to deactivation of NF-kappaB. Collectively, these results suggest that H. pylori activates NF-kappaB through an intracellular signaling pathway that involves IkappaB kinase and NF-kappaB-inducing kinase, leading to CCL20 gene transcription, and that Hsp90 is a crucial regulator of H. pylori-induced CCL20 expression, presumably contributing to the immune response in H. pylori.

Impact of weight loss on circulating IL-1, IL-6, IL-8, TNF-alpha, VEGF-A, VEGF-C and midkine in gastroesophageal cancer patients

OBJECTIVE

Proinflammatory cytokines are involved in cancer-related weight loss, but the involvement of VEGF-A, VEGF-C, IL-8 and midkine in gastroesophageal cancer patients remains unknown.

DESIGN AND METHODS

Serum IL-1, IL-6, IL-8, TNF-alpha, VEGF-A, VEGF-C, and midkine were evaluated in 96 cancer patients and 42 controls using ELISAs and were related to the occurrence of weight loss, patient's age, gender and BMI, cancer TNM status and blood cell counts.

RESULTS

All cytokines were elevated in cancer patients with further up-regulation of IL-6, IL-8, midkine and VEGF-A in cachexia. Underweight, midkine and VEGF-A were found independent indicators of weight loss. Primary tumor seems to be a major source of pro-cachectic cytokines, yet neutrophils and platelets also contribute to cytokine elevation.

CONCLUSIONS

IL-6 and IL-8, and probably midkine and VEGF-A, appear to participate in the development of cancer-related cachexia in gastroesophageal malignancies, although a detailed mechanism underlying cytokine involvement needs to be elucidated.

Heat shock protein 90 inhibitors prolong survival, attenuate inflammation, and reduce lung injury in murine sepsis

RATIONALE

Severe sepsis is the leading cause of death for patients in intensive care units. Patients with severe sepsis develop multiple organ failure, including acute lung injury (ALI), resulting from a deregulated inflammatory response. Inhibitors of the ubiquitous chaperone, heat shock protein 90 (Hsp90), block the activity of certain proinflammatory mediators in vitro. We hypothesized that Hsp90 inhibitors may ameliorate the inflammation and ALI associated with severe sepsis.

OBJECTIVES

To test the hypothesis that Hsp90 inhibitors prolong survival, attenuate inflammation, and reduce lung injury in a murine model of sepsis.

METHODS

Male C57BL/6 mice received either one of two Hsp90 inhibitors, radicicol or 17-allylaminodemethoxygeldanamycin (17-AAG), 24, 12, 6, and 0 hours before receiving a lethal dose of endotoxin (6.75 x 10(4) endotoxin units/g body weight). Outcomes included survival and parameters of systemic inflammation (plasma neutrophil, cytokine, chemokine, and nitrite/nitrate levels), pulmonary inflammation (lung nuclear factor-kappaB and myeloperoxidase activities, inducible nitric oxide synthase expression, inducible nitric oxide synthase-Hsp90 complex formation, and leukocyte infiltration), and lung injury (pulmonary capillary leak and lung function).

MEASUREMENTS AND MAIN RESULTS

Mice pretreated with vehicle and receiving endotoxin exhibited 100% 24-hour lethality, a dramatic increase in all parameters of systemic and pulmonary inflammation, increased capillary leak, and reduced lung function. Compared with them, mice receiving either radicicol or 17-AAG before endotoxin exhibited prolonged survival, reduced or abolished increases in systemic and pulmonary inflammatory parameters, attenuated capillary leak, and restored, normal lung function.

CONCLUSIONS

Hsp90 inhibitors may offer a new pharmacological tool in the management of severe sepsis and severe sepsis-induced ALI.

Analysis of the defence phosphoproteome ofArabidopsis thaliana using differential mass tagging

Despite recent advances in proteomic technologies, quantitative analysis of the proteome remains a challenging task. Phosphorylation of proteins is central to signal transduction pathways and plays an important role in plant defence against pathogens, although the immediate targets of kinases remain elusive. Determining changes in the phosphoproteome during the defence response is a major goal in molecular plant pathology. In this first description of the novel mass tagging strategy (iTRAQ Applied Biosystems) applied to plant pathogen interactions, we describe early changes to the phosphoproteome of Arabidopsis thaliana during the defence response to Pseudomonas syringae pv. tomato DC3000. We identified five proteins which showed reproducible differences between a control and three different bacterial challenges, thus identifying proteins potentially phosphorylated as part of a plant basal defence response. Four of the five proteins a dehydrin, a putative p23 co-chaperone, heat shock protein 81 and a plastid-associated protein (PAP)/fibrillin, are known to be phosphorylated or have potential phosphorylation sites. One further protein, the large subunit of Rubisco, showed a significant difference between tissue undergoing the hypersensitive response and a basal defence response. We document the reproducibility, utility and problems associated with this approach.

Geldanamycin increases 4-hydroxynonenal (HNE)-induced cell death in human retinal pigment epithelial cells

Development of age-related macular degeneration (AMD) is associated with functional abnormalities and cell death in retinal pigment epithelial (RPE) cells attributable to oxidative stress. To minimize the adverse effects of oxidative stress, cells activate their defence systems, e.g., via increased expression of heat shock protein (Hsp), activation of stress sensitive AP-1 and NF-kappaB transcription factors. In this study, we examined the accumulation of Hsp70 protein, activation of AP-1 and NF-kappaB transcription factors in human ARPE-19 cells subjected to a 4-hydroxynonenal (HNE)-induced oxidative stress. In addition, the influence of Hsp90 inhibitor geldanamycin (GA) was studied in HNE-treated cells. Mitochondrial metabolic activity and apoptosis were determined to evaluate cell death in the ARPE-19 cells. The ARPE-19 cells showed increased accumulation of Hsp70 protein before of the cytotoxic hallmarks appearing in response to HNE. In contrast, increased DNA-binding activities of AP-1 or NF-kappaB transcription factors were not seen under HNE insults. Interestingly, GA significantly increased cell death in the HNE-treated cells, which was involved in caspase-3 independent apoptosis. This study reveals that the Hsps have an important role in the cytoprotection of RPE cells subjected to HNE-derived oxidative stress.