Selective regulation of ICAM-1 and RANTES gene expression after ICAM-1 ligation on human renal fibroblasts

Gut-tropic T cells and extra-intestinal autoimmune diseases

Gut-tropic T cells primarily originate from gut-associated lymphoid tissue (GALT), and gut-tropic integrins mediate the trafficking of the T cells to the gastrointestinal tract, where their interplay with local hormones dictates the residence of the immune cells in both normal and compromised gastrointestinal tissues. Targeting gut-tropic integrins is an effective therapy for inflammatory bowel disease (IBD). Gut-tropic T cells are further capable of entering the peripheral circulatory system and relocating to multiple organs. There is mounting evidence indicating a correlation between gut-tropic T cells and extra-intestinal autoimmune disorders. This review aims to systematically discuss the origin, migration, and residence of gut-tropic T cells and their association with extra-intestinal autoimmune-related diseases. These discoveries are expected to offer new understandings into the development of a range of autoimmune disorders, as well as innovative approaches for preventing and treating the diseases.

Secretome of Adipose-Derived Stem Cells Cultured in Platelet Lysate Improves Migration and Viability of Keratinocytes

Chronic wounds depict a silent epidemic challenging medical professionals worldwide. Regenerative medicine uses adipose-derived stem cells (ADSC) in promising new therapies. In this study, platelet lysate (PL) as a xenogen-free substitute for foetal bovine serum (FBS) in ADSC culture was used to create an ADSC secretome containing cytokines for optimal wound healing conditions. The ADSC secretome was tested on keratinocytes for migrational behaviour and viability. Therefore, human ADSC were characterized under FBS (10%) and PL (5% and 10%) substitution, regarding morphology, differentiation, viability, gene and protein expression. ADSC were then cultured in 5% PL and their secretome was used for stimulation of keratinocyte migration and viability. To enhance the effect, ADSC were treated with Epithelial Growth Factor (EGF, 100 ng/mL) and hypoxia (1% O₂). In both PL and FBS groups, ADSC expressed typical stem cell markers. PL induced a significantly higher increase in cell viability compared to FBS substitution. ADSC secretome contained various beneficial proteins which enhance the wound healing capacity of keratinocytes. This could be optimized treating ADSC with hypoxia and EGF. In conclusion, the study shows that ADSC cultivated in 5% PL can effectively support wound healing conditions and can be considered as a promising new therapy for individual treatment of chronic wound disorders.

ICAM-1-mediated osteoblast-T lymphocyte direct interaction increases mineralization through TGF-β1 suppression

Modulation of osteoblast functions by T lymphocytes is important in inflammation-associated mineralized tissue diseases. The study aimed to determine whether direct interaction between these two cell types affects osteoblast functions and mineralization. The results showed that direct contact between the two cell types was evident by scanning electron microscopy and transmission electron microscopy. Under osteogenic induction, higher hydroxyapatite precipitation was observed in cocultures with direct contact with T lymphocytes compared with that by osteoblasts cultured alone. Cocultures without direct cell contact caused a decrease in mineralization. Direct cell contact also upregulated intercellular adhesion molecule (ICAM)-1 and simultaneously downregulated transforming growth factor (TGF)-β1 in osteoblasts. However, the downregulation of TGF-β1 was reversed by ICAM-1 blocking. Exogenously added TGF-β1 in cocultures with direct cell contact suppressed mineralization. In conclusion, studies are consistent with ICAM-1-mediated direct contact between osteoblasts and T lymphocytes increasing mineralization via downregulation of TGF-β1 in osteoblasts in vitro. This suggests a possible unexpected, but crucial, role of T lymphocytes in enhancing matrix mineralization during the repair process in vivo. The study identifies ICAM-1/TGF-β1 as possible novel therapeutic targets for the treatment and prevention of inflammation-associated mineralized tissue diseases.

Gene regulation of intracellular adhesion molecule-1 (ICAM-1): A molecule with multiple functions

Intracellular adhesion molecule 1 (ICAM-1) is one of the most extensively studied inducible cell adhesion molecules which is responsible for several immune functions like T cell activation, extravasation, inflammation, etc. The molecule is constitutively expressed over the cell surface and is regulated up / down in response to inflammatory mediators like cellular stress, proinflammatory cytokines, viral infection. These stimuli modulate the expression of ICAM-1 primarily through regulating the ICAM-1 gene transcription. On account of the presence of various binding sites for NF-κB, AP-1, SP-1, and many other transcription factors, the architecture of the ICAM-1 promoter become complex. Transcription factors in union with other transcription factors, coactivators, and suppressors promote their assembly in a stereospecific manner on ICAM-1 promoter which mediates ICAM-1 regulation in response to different stimuli. Along with transcriptional regulation, epigenetic modifications also play a pivotal role in controlling ICAM-1 expression on different cell types. In this review, we summarize the regulation of ICAM-1 expression both at the transcriptional as well as post-transcriptional level with an emphasis on transcription factors and signaling pathways involved.

MAPK10 Expression as a Prognostic Marker of the Immunosuppressive Tumor Microenvironment in Human Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains a devastating malignancy worldwide due to lack of effective therapy. The immune-rich contexture of HCC tumor microenvironment (TME) makes this tumor an appealing target for immune-based therapies; however, the immunosuppressive TME is still a major challenge for more efficient immunotherapy in HCC. Using bioinformatics analysis based on the TCGA database, here we found that MAPK10 is frequently down-regulated in HCC tumors and significantly correlates with poor survival of HCC patients. HCC patients with low MAPK10 expression have lower expression scores of tumor infiltration lymphocytes (TILs) and stromal cells in the TME and increased scores of tumor cells than those with high MAPK10 expression. Further transcriptomic analyses revealed that the immune activity in the TME of HCC was markedly reduced in the low-MAPK10 group of HCC patients compared to the high-MAPK10 group. Additionally, we identified 495 differentially expressed immune-associated genes (DIGs), with 482 genes down-regulated and 13 genes up-regulated in parallel with the decrease of MAPK10 expression. GO enrichment and KEGG pathway analyses indicated that the biological functions of these DIGs included cell chemotaxis, leukocyte migration and positive regulation of the response to cytokine–cytokine receptor interaction, T cell receptor activation and MAPK signaling pathway. Protein–protein interaction (PPI) analyses of the 495 DIGs revealed five potential downstream hub genes of MAPK10, including SYK, CBL, VAV1, LCK, and CD3G. Several hub genes such as SYK, LCK, and VAV1 could respond to the immunological costimulatory signaling mediated by the transmembrane protein ICAM1, which was identified as a down-regulated DIG associated with low-MAPK10 expression. Moreover, ectopic overexpression or knock-down of MAPK10 could up-regulate or down-regulate ICAM1 expression via phosphorylation of c-jun at Ser63 in HCC cell lines, respectively. Collectively, our results demonstrated that MAPK10 down-regulation likely contributes to the immunosuppressive TME of HCC, and this gene might serve as a potential immunotherapeutic target and a prognostic factor for HCC patients.

MEKK1 Regulates Chemokine Expression in Mammary Fibroblasts: Implications for the Breast Tumor Microenvironment

Breast tumors contain both transformed epithelial cells and non-transformed stroma cells producing secreted factors that can promote metastasis. Previously, we demonstrated that the kinase MEKK1 regulates cell migration and gene expression, and that transgene-induced breast tumor metastasis is markedly inhibited in MEKK1-deficient mice. In this report, we examined the role of MEKK1 in stroma cell gene expression and the consequent effect on breast tumor cell function. Using a heterotypic cell system to quantify the effect of stroma cells on breast tumor cell function, we discovered that MEKK1-/- fibroblasts are significantly less effective at inducing tumor cell invasion than MEKK1+/+ fibroblasts. Expression array analysis revealed that both baseline and tumor cell-induced expression of the chemokines CCL3, CCL4, and CCL5 were markedly reduced in MEKK1-/- mammary fibroblasts. By focusing on the role of MEKK1 in CCL5 regulation, we discovered that MEKK1 kinase activity promotes CCL5 expression, and inactive mutant MEKK1 strongly inhibits CCL5 transcription. CCL5 and the other MEKK1-dependent chemokines are ligands for the GPCR CCR5, and we show that the CCR5 antagonist Maraviroc strongly inhibits fibroblast-induced tumor cell migration. Finally, we report that fibroblast growth factor 5 (FGF-5) is secreted by MDA-MB 231 cells, that FGF-5 activates MEKK1 effectors ERK1/2 and NFκB in fibroblasts, and that chemical inhibition of NFκB inhibits CCL5 expression. Our results suggest that MEKK1 contributes to the formation of a breast tumor microenvironment that supports metastasis by promoting expression of stroma cell chemokine genes in response to tumor cell-induced paracrine signaling.

Palm Fruit Bioactives modulate human astrocyte activity in vitro altering the cytokine secretome reducing levels of TNFα, RANTES and IP-10

Neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, are becoming more prevalent and an increasing burden on society. Neurodegenerative diseases often arise in the milieu of neuro-inflammation of the brain. Reactive astrocytes are key regulators in the development of neuro-inflammation. This study describes the effects of Palm Fruit Bioactives (PFB) on the behavior of human astrocytes which have been activated by IL-1β. When activated, the astrocytes proliferate, release numerous cytokines/chemokines including TNFα, RANTES (CCL5), IP-10 (CXCL10), generate reactive oxygen species (ROS), and express specific cell surface biomarkers such as the Intercellular Adhesion Molecule (ICAM), Vascular Cellular Adhesion Molecule (VCAM) and the Neuronal Cellular Adhesion Molecule (NCAM). Interleukin 1-beta (IL-1β) causes activation of human astrocytes with marked upregulation of pro-inflammatory genes. We show significant inhibition of these pro-inflammatory processes when IL-1β-activated astrocytes are exposed to PFB. PFB causes a dose-dependent and time-dependent reduction in specific cytokines: TNFα, RANTES, and IP-10. We also show that PFB significantly reduces ROS production by IL-1β-activated astrocytes. Furthermore, PFB also reduces the expression of ICAM and VCAM, both in activated and naïve human astrocytes in vitro. Since reactive astrocytes play an essential role in the neuroinflammatory state preceding neurodegenerative diseases, this study suggests that PFB may have a potential role in their prevention and/or treatment.

TLR4 modulates inflammatory gene targets in the retina during Bacillus cereus endophthalmitis

Background

Endophthalmitis is a serious intraocular infection that frequently results in significant inflammation and vision loss. Because current therapeutics are often unsuccessful in mitigating damaging inflammation during endophthalmitis, more rational targets are needed. Toll-like receptors (TLRs) recognize specific motifs on invading pathogens and initiate the innate inflammatory response. We reported that TLR4 contributes to the robust inflammation which is a hallmark of Bacillus cereus endophthalmitis. To identify novel, targetable host inflammatory factors in this disease, we performed microarray analysis to detect TLR4-dependent changes to the retinal transcriptome during B. cereus endophthalmitis.

Results

C57BL/6 J and TLR4^−/− mouse eyes were infected with B. cereus and retinas were harvested at 4 h postinfection, a time representing the earliest onset of neutrophil infiltration. Genes related to acute inflammation and inflammatory cell recruitment including CXCL1 (KC), CXCL2 (MIP2-α), CXCL10 (IP-10), CCL2 (MCP1), and CCL3 (MIP1-α)) were significantly upregulated 5-fold or greater in C57BL/6 J retinas. The immune modulator IL-6, intercellular adhesion molecule ICAM1, and the inhibitor of cytokine signal transduction SOCS3 were upregulated 25-, 11-, and 10-fold, respectively, in these retinas. LIF, which is crucial for photoreceptor cell survival, was increased 6-fold. PTGS2/COX-2, which converts arachidonic acid to prostaglandin endoperoxide H2, was upregulated 9-fold. PTX3, typically produced in response to TLR engagement, was induced 15-fold. None of the aforementioned genes were upregulated in TLR4^−/− retinas following B. cereus infection.

Conclusions

Our results have identified a cohort of mediators driven by TLR4 that may be important in regulating pro-inflammatory and protective pathways in the retina in response to B. cereus intraocular infection. This supports the prospect that blocking the activation of TLR-based pathways might serve as alternative targets for Gram-positive and Gram-negative endophthalmitis therapies in general.

Electronic supplementary material

The online version of this article (10.1186/s12886-018-0764-8) contains supplementary material, which is available to authorized users.

Eucalyptus robusta leaves methanolic extract suppresses inflammatory mediators by specifically targeting TLR4/TLR9, MPO, COX2, iNOS and inflammatory cytokines in experimentally-induced endometritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Bacterial endometritis is one of the major causes of reproductive disorders including infertility in farm animals. Antibiotics are generally used for treatment of such disorders but now a days residues of antibiotics are of great public health concern, therefore, phytoremediation is being considered as an alternative to use of antibiotics.

AIM OF THE STUDY

Present study was undertaken to investigate the efficacy of Eucalyptus robusta leaves methanolic extract against endometritis along with the possible mechanism of action especially targeting inflammatory biomarkers.

MATERIALS AND METHODS

Bacterial endometritis was produced using clinical isolates of E. coli and Staphyloccocus aureus from bovines (cows and buffaloes) endometritis cases. After seven days of inoculation of the mixed bacterial culture, endometritis was confirmed based on the presence of visible pus and edema, thinning of endometrial lining and presence of large number of polymorphonuclear cells and bacterial load in uterine flushing. Female Wistar rats were divided in to five groups namely control, sham-operated, endometritis, endometritis plus Eucalyptus leaves extract and endometritis plus cefixime. Serum specific inflammatory biomarkers (interleukin-1β, interleukin-10, tumor necrosis factor-α, intercellular adhesion molecule-1, serum amyloid A) and myleoperoxidase, toll like receptors-4 and -9, inducible nitric oxide synthase, nitric oxide, cyclooxygenase 1 and 2 were estimated in uterine tissues using ELISA kits.

RESULTS

Interleukin-10, serum amyloid A, myleoperoxidase, toll like receptors-4 and-9, cyclooxygenase-2, inducible nitric oxide synthase and nitric oxide were significantly increased while non significant increase in interleukin-1β, cycloxygenase-1 and intercellular adhesion molecule-1 were observed but level of tumor necrosis factor-α was found decreased in rats of endometritis group. Histopathological lesions in uterus showed efficient induction of endometritis by presence of inflammatory cells which are lessened effectively after treatment with Eucalyptus leaves extract. Eucalyptus robusta leaves extract produced curative and protective effect against endometritis and results were comparable to or even better than cefixime.

CONCLUSIONS

Eucalyptus robusta leaves extract possess promising antibacterial activity and efficacy against experimental endometritis and, therefore, holds promising potential for development of effective formulation for treatment of endometritis in animals.

Role of liver ICAM-1 in metastasis

Intercellular adhesion molecule (ICAM)-1, is a transmembrane glycoprotein of the immunoglobulin (Ig)-like superfamily, consisting of five extracellular Ig-like domains, a transmembrane domain and a short cytoplasmic tail. ICAM-1 is expressed in various cell types, including endothelial cells and leukocytes, and is involved in several physiological processes. Furthermore, it has additionally been reported to be expressed in various cancer cells, including melanoma, colorectal cancer and lymphoma. The majority of studies to date have focused on the expression of the ICAM-1 on the surface of tumor cells, without research into ICAM-1 expression at sites of metastasis. Cancer cells frequently metastasize to the liver, due to its unique physiology and specialized liver sinusoid capillary network. Liver sinusoidal endothelial cells constitutively express ICAM-1, which is upregulated under inflammatory conditions. Furthermore, liver ICAM-1 may be important during the development of liver metastasis. Therefore, it is necessary to improve the understanding of the mechanisms mediated by this adhesion molecule in order to develop host-directed anticancer therapies.

Identification of Pathways in Liver Repair Potentially Targeted by Secretory Proteins from Human Mesenchymal Stem Cells

BACKGROUND

The beneficial impact of mesenchymal stem cells (MSC) on both acute and chronic liver diseases has been confirmed, although the molecular mechanisms behind it remain elusive. We aim to identify factors secreted by undifferentiated and hepatocytic differentiated MSC in vitro in order to delineate liver repair pathways potentially targeted by MSC.

METHODS

Secreted factors were determined by protein arrays and related pathways identified by biomathematical analyses.

RESULTS

MSC from adipose tissue and bone marrow expressed a similar pattern of surface markers. After hepatocytic differentiation, CD54 (intercellular adhesion molecule 1, ICAM-1) increased and CD166 (activated leukocyte cell adhesion molecule, ALCAM) decreased. MSC secreted different factors before and after differentiation. These comprised cytokines involved in innate immunity and growth factors regulating liver regeneration. Pathway analysis revealed cytokine-cytokine receptor interactions, chemokine signalling pathways, the complement and coagulation cascades as well as the Januskinase-signal transducers and activators of transcription (JAK-STAT) and nucleotide-binding oligomerization domain-like receptor (NOD-like receptor) signalling pathways as relevant networks. Relationships to transforming growth factor β (TGF-β) and hypoxia-inducible factor 1-α (HIF1-α) signalling seemed also relevant.

CONCLUSION

MSC secreted proteins, which differed depending on cell source and degree of differentiation. The factors might address inflammatory and growth factor pathways as well as chemo-attraction and innate immunity. Since these are prone to dysregulation in most liver diseases, MSC release hepatotropic factors, potentially supporting liver regeneration.

Role of high endothelial postcapillary venules and selected adhesion molecules in periodontal diseases: a review

Periodontitis is accompanied by the proliferation of small blood vessels in the gingival lamina propria. Specialized postcapillary venules, termed periodontal high endothelial-like venules, are also present, and demonstrate morphological and functional traits similar to those of high endothelial venules (HEVs) in lymphatic organs. The suggested role of HEVs in the pathogenesis of chronic periodontitis involves participation in leukocyte transendothelial migration and therefore proinflammatory effects appear. Recent observations suggest that chronic periodontitis is an independent risk factor for systemic vascular disease and may result in stimulation of the synthesis of acute phase protein by cytokines released by periodontal high endothelial cells (HECs). However, tissue expression of HEV-linked adhesion molecules has not been evaluated in the gingiva of patients with chronic periodontitis. This is significant in relation to potential therapy targeting expression of the adhesion molecules. In this review, current knowledge of HEV structure and the related expression of four surface adhesion molecules of HECs [CD34, platelet endothelial cell adhesion molecule 1, endoglin and intercellular adhesion molecule 1 (ICAM-1)], involved in the key steps of the adhesion cascade in periodontal diseases, are discussed. Most studies on the expression of adhesion molecules in the development and progression of periodontal diseases pertain to ICAM-1 (CD54). Studies by the authors demonstrated quantitatively similar expression of three of four selected surface markers in gingival HEVs of patients with chronic periodontitis and in HEVs of reactive lymph nodes, confirming morphological and functional similarity of HEVs in pathologically altered tissues with those in lymphoid tissues.

Cannabidiol inhibits lung cancer cell invasion and metastasis via intercellular adhesion molecule-1

Cannabinoids inhibit cancer cell invasion via increasing tissue inhibitor of matrix metalloproteinases-1 (TIMP-1). This study investigates the role of intercellular adhesion molecule-1 (ICAM-1) within this action. In the lung cancer cell lines A549, H358, and H460, cannabidiol (CBD; 0.001-3 μM) elicited concentration-dependent ICAM-1 up-regulation compared to vehicle via cannabinoid receptors, transient receptor potential vanilloid 1, and p42/44 mitogen-activated protein kinase. Up-regulation of ICAM-1 mRNA by CBD in A549 was 4-fold at 3 μM, with significant effects already evident at 0.01 μM. ICAM-1 induction became significant after 2 h, whereas significant TIMP-1 mRNA increases were observed only after 48 h. Inhibition of ICAM-1 by antibody or siRNA approaches reversed the anti-invasive and TIMP-1-upregulating action of CBD and the likewise ICAM-1-inducing cannabinoids Δ(9)-tetrahydrocannabinol and R(+)-methanandamide when compared to isotype or nonsilencing siRNA controls. ICAM-1-dependent anti-invasive cannabinoid effects were confirmed in primary tumor cells from a lung cancer patient. In athymic nude mice, CBD elicited a 2.6- and 3.0-fold increase of ICAM-1 and TIMP-1 protein in A549 xenografts, as compared to vehicle-treated animals, and an antimetastatic effect that was fully reversed by a neutralizing antibody against ICAM-1 [% metastatic lung nodules vs. isotype control (100%): 47.7% for CBD + isotype antibody and 106.6% for CBD + ICAM-1 antibody]. Overall, our data indicate that cannabinoids induce ICAM-1, thereby conferring TIMP-1 induction and subsequent decreased cancer cell invasiveness.

MCP-1/CCR-2-double-deficiency severely impairs the migration of hematogenous inflammatory cells following transient cerebral ischemia in mice

Monocyte chemoattractant protein-1 (MCP-1) and its receptor CCR-2 are known to play a major role in inflammatory responses after cerebral ischemia. Mice deficient in either MCP-1 or CCR-2 have been reported to develop smaller infarct sizes and show decreased numbers of infiltrating inflammatory cells. In the present study we used green fluorescent protein (GFP) transgenic mice to investigate the effect of MCP-1/CCR-2-double deficiency on the recruitment of inflammatory cells in a model of both, mild and severe cerebral ischemia. We show that MCP-1/CCR-2-double deficiency virtually entirely abrogates the recruitment of hematogenous macrophages and significantly reduces neutrophil migration to the ischemic brain 4 and 7 days following focal cerebral ischemia. This argues for a predominant role of the MCP-1/CCR-2 axis in chemotaxis of monocytes despite a wide redundancy in the chemokine-receptor-system. Chemokine analysis revealed that even candidates known to be involved in monocyte and neutrophil recruitment like MIP-1α, CXCL-1, C5a, G-CSF and GM-CSF showed a reduced and delayed or even a lack of relevant compensatory response in MCP-1(-/-)/CCR-2(-/-)-mice. Solely, chemokine receptor 5 (CCR-5) increased early in both, but rose above wildtype levels at day 7 in MCP-1(-/-)/CCR-2(-/-)-animals, which might explain the higher number of activated microglial cells compared to control mice. Our study was, however, not powered to investigate infarct volumes. Further studies are needed to clarify whether these mechanisms of inflammatory cell recruitment might be essential for early infarct development and final infarct size and to evaluate potential therapeutic implications.

Monocytes induce proximal tubular epithelial-mesenchymal transition through NF-kappa B dependent upregulation of ICAM-1

Inflammatory cell infiltration plays a key role in the pathogenesis of tubulointerstitial damage in chronic renal diseases. In addition to secreting the profibrotic cytokines, monocytes themselves have been demonstrated to be directly associated with renal fibrogenesis. However, how infiltrating monocytes interact with resident cells and the underlying mechanisms remain elusive. In this study we investigated the effects of monocytes on phenotypic changes of human proximal tubular HK-2 cells. The typical epithelial cell morphology of HK-2 cells disappeared after co-culture with monocytes, accompanied by decreased E-cadherin expression, and increased α-SMA and fibronectin expression, suggesting that HK-2 cells undergo epithelial-mesenchymal transition (EMT). Further analysis revealed that the effects were dependent on direct contact of the two types of cells as conditioned medium had no effects. Interestingly, administration of CD18 antibody directly inhibited this process. Furthermore, by microarray and RT-PCR we found that NF-kB signaling may play a role in this process and blockade of this signaling pathway in HK-2 cells could inhibit ICAM-1 expression and EMT phenotypes. Taken together, these findings suggest that monocytes infiltration could directly induce EMT of HK-2 cells via upregulation ICAM-1 through NF-kB signaling pathway.

SARS-CoV accessory protein 3b induces AP-1 transcriptional activity through activation of JNK and ERK pathways

The outbreak of severe acute respiratory syndrome (SARS) in 2003 in China, characterized by atypical pneumonia, was associated with the emergence of a novel coronavirus named severe acute respiratory syndrome coronavirus (SARS-CoV). Eight accessory proteins of SARS coronavirus were the suspected players in the pathogenesis of the virus. Among them, protein 3b localizes to the nucleus and behaves as an interferon antagonist by inhibiting IRF3 activation. However, the effect of 3b on the activity of other common host transcription factors remains unexplored. In this work, we studied the effect of 3b on the transcriptional activity of AP-1. Our findings elucidate augmentation of AP-1-dependent gene expression in 3b-transfected Huh7 cells. Reporter gene and mobility shift assays depict an increase in the AP-1 transcriptional and DNA binding activity in the presence of 3b. This increase in activity correlates with the activation of ERK and JNK pathways. Furthermore, 3b expression potentiates AP-1-driven promoter activity of proinflammatory cytokine MCP-1, suggesting a plausible role for 3b as a virulence factor that might function by upregulating AP-1-dependent cytokine levels in SARS-CoV infection.

The chemokine monocyte chemoattractant protein-1 contributes to renal dysfunction in swine renovascular hypertension

Renal artery stenosis (RAS) causes renovascular hypertension and renal damage, which may result from tissue inflammation. We have previously shown that the kidney in RAS exhibits increased expression of monocyte chemoattractant protein (MCP)-1, but its contribution to renal injury remained unknown. This study tested the hypothesis that MCP-1 contributes to renal injury and dysfunction in the stenotic kidney.

METHODS

Kidney hemodynamics, function, and endothelial function were quantified in pigs after 10 weeks of experimental RAS (n = 7), RAS supplemented with the MCP-1 inhibitor bindarit (RAS + bindarit, 50 mg/kg/day orally, n = 6), and normal controls (n = 8). Renal inflammation was assessed by the immunoreactivity of MCP-1, its receptor chemotactic cytokine receptor 2, and NFkappaB, and oxidative stress by nicotinamide adenine dinucleotide phosphate-oxidase expression and in-situ superoxide production. Renal microvascular density was evaluated by micro-CT and fibrosis by trichrome staining, collagen-I immunostaining, and hydroxyproline content.

RESULTS

After 10 weeks of RAS, blood pressure was similarly elevated in RAS and RAS + bindarit. Compared with normal controls, stenotic RAS kidneys had decreased renal blood flow (5.4 +/- 1.6 vs. 11.4 +/- 1.0 ml/min/kg, P < 0.05) and glomerular filtration rate and impaired endothelial function, which were significantly improved in bindarit-treated RAS pigs (to 8.4 +/- 0.8 ml/min/kg, P < 0.05 vs. RAS). Furthermore, bindarit markedly decreased tubulointerstitial (but not vascular) oxidative stress, inflammation, and fibrosis, and slightly increased renal microvascular density. The impaired renovascular endothelial function, increased oxidative-stress, and fibrosis in the contralateral kidney were also improved by bindarit.

CONCLUSION

MCP-1 contributes to functional and structural impairment in the kidney in RAS, mainly in the tubulointerstitial compartment. Its inhibition confers renoprotective effects by blunting renal inflammation and thereby preserving the kidney in chronic RAS.

Effects of IS-741, a synthetic anti-inflammatory agent, on bleomycin-induced lung injury in mice

Bleomycin (BLM)-induced lung injury consists of excessive inflammatory cell infiltration and fibrosis. IS-741 has been reported to be an anti-inflammatory drug through an inhibitory action on cell adhesion. In this study we investigated whether IS-741 could inhibit the progression of pulmonary fibrosis through inflammatory cell infiltration. Lung injury was induced in female C57BL/6 mice by intratracheal instillation of BLM. IS-741 was administered daily intraperitoneally. The hydroxyproline content and fluid content in the lung on Day 28 were significantly lower in the IS-741-treated mice. The histological degree of lung injury or fibrosis was reduced in IS-741-treated mice. Administration of IS-741 caused significant reduction in the absolute number of total cells, monocyte chemoattractant protein (MCP)-1, and cysteinyl leukotriene (cysLTs) levels in bronchoalveolar lavage fluid on Day 7. Furthermore, the hydroxyproline content was significantly lower in IS-741-treated mice even though IS-741 was started on Day 14 after BLM instillation. Treatment with IS-741 had an inhibitory effect on BLM-induced lung injury and fibrosis via the repression of MCP-1 or cysLTs in this murine experimental model.

Pathogenic role of NF-kappaB activation in tubulointerstitial inflammatory lesions in human lupus nephritis

In vitro and in vivo experimental studies suggest that the transcription factor NF-kappaB plays a role in tubulointerstitial injury. We investigated possible cellular and molecular mechanisms involving NF-kappaB activation in the progression of tubulointerstitial lesions in human lupus nephritis (LN). Paraffin-embedded renal biopsies from 50 patients with LN and six control patients with minimal change disease (MCD) were examined by Southwestern histochemistry for in situ detection of active NF-kappaB and AP-1. Immunohistochemistry was performed to examine the expression of NF-kappaB, AP-1, and NF-kappaB regulatory proteins (IkappaB-alpha, p-IkappaB-alpha, and IKK-alpha proteins), as well as NF-kappaB and AP-1 downstream target proinflammatory molecules (ICAM-1, TNF-alpha, IL-1beta, IL-6, and GM-CSF) and NF-kappaB upstream signaling molecules (CD40 and CD40L). We observed extensive upregulation of activated NF-kappaB in renal tubular cells and interstitial cells, in parallel with overactivation of transcription factor AP-1 in LN, as compared with normal controls and MCD. Tubular expression of activated NF-kappaB correlated well with the degree of tubulointerstitial histopathological indices and/or renal function. Tubulointerstitial IKK-alpha expression was specifically upregulated in LN. IkappaB-alpha and p-IkappaB-alpha were detected only in interstitial cells in LN. Tubulointerstitial expression levels of NF-kappaB and AP-1 downstream inflammatory molecules and NF-kappaB upstream signaling molecules CD40 and CD40L were markedly enhanced in LN as compared with MCD or normal controls and were associated with tubulointerstitial histopathological indices and/or renal function. The results suggest that altered IKK-alpha expression and NF-kappaB activation along with AP-1 overexpression may play a pathogenic role in tubulointerstitial injury in human LN mediated through a network of downstream proinflammatory molecules.

IS-741 attenuates local migration of monocytes and subsequent pancreatic fibrosis in experimental chronic pancreatitis induced by dibutyltin dichloride in rats

OBJECTIVES

Chronic pancreatitis consists of excessive leukocyte infiltration and fibrosis. IS-741 has been reported to be an antiinflammatory drug through an inhibitory action on cell adhesion. In this study, we investigated whether IS-741 could inhibit the progression of pancreatic fibrosis through monocyte infiltration. Moreover, we investigated the effect of IS-741 on rat pancreatic stellate cells (PSCs).

METHODS

Chronic pancreatitis was induced by dibutyltin dichloride in rats. From days 7 to 28 after dibutyltin dichloride application, IS-741 or distilled water was administered. At days 14 and 28, histological [hematoxylin-eosin stain and immunostain for ED1 and [alpha] smooth muscle actin (alpha-SMA)] and biochemical evaluations (intrapancreatic amylase, protein, cytokines, chemokines, and alpha-SMA) were performed. In vitro, rat PSCs were incubated with cytokine, chemokine, and growth factor simultaneously with IS-741, and their proliferation and activation were examined.

RESULTS

Histologically, IS-741 inhibited pancreatic fibrosis and decreased the number of ED1- and [alpha]-SMA-positive cells. The intrapancreatic expression of cytokines, chemokine, and [alpha]-SMA were also decreased. In vitro, IS-741 has no direct effect on the proliferation, alpha-SMA expression, and collagen synthesis of PSCs.

CONCLUSIONS

These results suggest that IS-741 suppressed macrophage infiltration and subsequent pancreatic fibrosis and that the infiltration of monocytes into pancreas is essential for pancreatic fibrosis.

Selective regulation of MAP kinases and chemokine expression after ligation of ICAM-1 on human airway epithelial cells

BACKGROUND

Intercellular adhesion molecule 1 (ICAM-1) is an immunoglobulin-like cell adhesion molecule expressed on the surface of multiple cell types, including airway epithelial cells. It has been documented that cross-linking ICAM-1 on the surface of leukocytes results in changes in cellular function through outside-inside signaling; however, the effect of cross-linking ICAM-1 on the surface of airway epithelial cells is currently unknown. The objective of this study was to investigate whether or not cross-linking ICAM-1 on the surface of airway epithelial cells phosphorylated MAP kinases or stimulated chemokine expression and secretion.

METHODS

The human lung adenocarcinoma (A549) cells and primary cultures of normal human bronchial epithelial (NHBE) cells were used in these studies. To increase ICAM-1 surface expression, cultures were stimulated with TNFalpha to enhance ICAM-1 surface expression. Following ICAM-1 upregulation, ICAM-1 was ligated with a murine anti-human ICAM-1 antibody and subsequently cross-linked with a secondary antibody (anti-mouse IgG(ab')2) in the presence or absence of the MAP kinase inhibitors. Following treatments, cultures were assessed for MAPK activation and chemokine gene expression and secretion. Control cultures were treated with murine IgG1 antibody or murine IgG1 antibody and anti-mouse IgG(ab')2 to illustrate specificity. Data were analyzed for significance using a one-way analysis of variance (ANOVA) with Bonferroni post-test correction for multiple comparisons, and relative gene expression was analyzed using the 2-DeltaDeltaCT method.

RESULTS

ICAM-1 cross-linking selectively phosphorylated both ERK and JNK MAP kinases as detected by western blot analysis. In addition, cross-linking resulted in differential regulation of chemokine expression. Specifically, IL-8 mRNA and protein secretion was not altered by ICAM-1 cross-linking, in contrast, RANTES mRNA and protein secretion was induced in both epithelial cultures. These events were specifically inhibited by the ERK inhibitor PD98059. Data indicates that ICAM-1 cross-linking stimulates a synergistic increase in TNFalpha-mediated RANTES production involving activation of ERK in airway epithelial cells.

CONCLUSION

Results demonstrate that cytokine induced ICAM-1 on the surface of airway epithelial cells induce outside-inside signaling through cross-linking ICAM-1, selectively altering intracellular pathways and cytokine production. These results suggest that ICAM-1 cross-linking can contribute to inflammation in the lung via production of the chemokine RANTES.

Cell expression of MMP-1 and TIMP-1 in co-cultures of human gingival fibroblasts and monocytes: the involvement of ICAM-1

Matrix metalloproteinase-1 (MMP-1) plays an important role in the degradation of collagen in inflammatory diseases. The aim of this study was to investigate the cellular expression of MMP-1 and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), in gingival fibroblasts co-cultured with monocytes and the possible mediating role of intercellular adhesion molecule-1 (ICAM-1). In co-cultures, the expression of MMP-1 and TIMP-1 increased in fibroblasts, but not in monocytes, although the number of MMP-1+ and TIMP-1+ adhered monocytes increased. Moreover, ICAM-1 expression in both fibroblasts and adhered monocytes increased. In the presence of an anti-ICAM-1 antibody, the expression of MMP-1 in fibroblasts decreased whereas the number of TIMP-1+ adhered monocytes increased. The p38 MAPK inhibitor SB203580 reduced MMP-1 expression in fibroblasts, as well as ICAM-1 expression in both fibroblasts and adhered monocytes. The results suggest that co-culture with monocytes enhances cellular expression of MMP-1 and TIMP-1 in gingival fibroblasts, and that the increased MMP-1 expression, in contrast to TIMP-1, is partly mediated by the adhesion molecule ICAM-1 and the p38 MAPK signal pathway.

The role of p38 MAPK in rhinovirus-induced monocyte chemoattractant protein-1 production by monocytic-lineage cells

Viral respiratory infections are a major cause of asthma exacerbations and can contribute to the pathogenesis of asthma. Major group human rhinovirus enters cells by binding to the cell surface molecule ICAM-1 that is present on epithelial and monocytic lineage cells. The focus of the resulting viral infection is in bronchial epithelia. However, previous studies of the cytokine dysregulation that follows rhinovirus infection have implicated monocytic lineage cells in establishing the inflammatory environment even though productive infection is not a result. We have determined that human alveolar macrophages and human peripheral blood monocytes release MCP-1 upon exposure to human rhinovirus 16 (HRV16). Indeed, we have found p38 MAPK activation in human alveolar macrophages within 15 min of exposure to HRV16, and this activation lasts up to 1 h. The targets of p38 MAPK activation include transcriptional activators of the MCP-1 promoter. The transcription factor ATF-2, a p38 MAPK substrate, is phosphorylated 45 min after HRV16 exposure. Furthermore, IkappaBalpha, the inhibitor of the transcription factor NF-kappaB, is degraded. Prevention of HRV16 binding was effective in blocking p38 MAPK activation, ATF-2 phosphorylation, and MCP-1 release. This is the first report of a relationship between HRV16 exposure, MCP-1 release and monocytic-lineage cells suggesting that MCP-1 plays a role in establishing the inflammatory microenvironment initiated in the human airway upon exposure to rhinovirus.

Hypoxia/reoxygenation stimulates Ca2+-dependent ICAM-1 mRNA expression in human aortic endothelial cells

Increased endothelial ICAM-1 expression is found in normal aging and in atherosclerosis and is related to the chronic effects of oxidative stress. We examined the Ca(2+)-dependence of ICAM-1 mRNA expression in human aortic endothelial cells (HAEC) exposed to hypoxia/reoxygenation (H/R) as a model of oxidative stress. HAEC were exposed to glucose-free hypoxia (95% N(2)/5% CO(2)) for 60 min and were then reoxygenated (21% O(2)/5% CO(2)) and observed for up to 6h. Reactive oxygen species (ROS) generation was measured by dichlorofluorescein fluorescence and ICAM-1 mRNA was assessed by Northern blot. Upon reoxygenation after hypoxia, ROS production occurred in HAEC and was inhibited by diphenyleneiodonium and by polyethylene glycol-catalase, suggesting the involvement of NADPH oxidase-derived hydrogen peroxide. Hypoxia alone did not increase either ROS production or ICAM-1 mRNA levels, but a 2.5-fold increase in ICAM-1 mRNA was noted by 30 min of reoxygenation. This was not observed in Ca(2+)-free buffer or in cells treated with diphenyleneiodonium. Thus, H/R upregulates ICAM-1 mRNA in HAEC by a Ca(2+)- and ROS-dependent mechanism. Characterizing the signaling pathways involved in H/R-induced adhesion molecule expression may result in a better understanding of the vascular biology of normal aging and the pathobiology of atherosclerosis.

Oxidized phospholipids increase interleukin 8 (IL-8) synthesis by activation of the c-src/signal transducers and activators of transcription (STAT)3 pathway

Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (Ox-PAPC) and its component phospholipids 1-palmitoyl-2-epoxyisoprostane-sn-glycero-3-phosphorylcholine (PEIPC) and 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphorylcholine induce endothelial cells to synthesize chemotactic factors, such as interleukin 8 (IL-8). We have shown recently that Ox-PAPC-mediated induction of IL-8 transcription is independent of NF-kappaB activation, a major transcription factor utilized by cytokines and lipopolysaccharide for the induction of IL-8 transcription. In this study, we provide evidence for the role of c-src in Ox-PAPC and, specifically, PEIPC-mediated IL-8 induction. Ox-PAPC and its component phospholipids induced a rapid and transient phosphorylation of c-src Tyr418, a hallmark of c-src activation, in human aortic endothelial cells (HAEC). Ox-PAPC-mediated IL-8 protein synthesis in HAEC was inhibited by Src family kinase inhibitors, PP1 and PP2, but not by an inactive analog, PP3. Transient expression of plasmids containing C-terminal Src kinase or kinase-deficient dominant-negative c-src resulted in a 72 and 50% reduction in Ox-PAPC-induced IL-8 promoter activation in human microvascular endothelial cells, respectively. In contrast, overexpression of v-src kinase resulted in a 4-fold increase in IL-8 promoter activation, without inducing NF-kappaB promoter activation. Furthermore, treatment of HAEC with Ox-PAPC and its component PEIPC induced the activation of STAT3 by phosphorylating Tyr705, a feature of STAT3 activation. STAT3 is a known downstream effector of c-src. Ox-PAPC-induced activation of STAT3 resulted in the translocation of STAT3 from the cytoplasm of HAEC into their nuclear compartment. Transient expression of a dominant-negative STAT3beta construct in HMEC strongly inhibited IL-8 induction by Ox-PAPC. Taken together, these data demonstrate the role of the c-src kinase/STAT3 pathway in Ox-PAPC-mediated IL-8 expression in endothelial cells.

Adhesion and signaling by B cell-derived exosomes: the role of integrins

Exosomes are nanometer-sized vesicles secreted by various cells, with potentially diverse roles in physiology. Although emphasis has been placed on their involvement in immune modulation, their potential for more wide-ranging biological effects has not been appreciated. A common exosome feature is the expression of adhesion molecules, which include the integrin family. We have for the first time addressed the possible function of B cell-derived exosome-integrins by examining adhesive interactions of exosomes (immobilized onto beads) with extracellular matrix (ECM) components and cytokine-treated fibroblasts. Integrin (beta1 and beta2) expression was demonstrated by Western blotting and flow cytometry. Binding studies (with blocking antibodies) demonstrated their function in adhesion to collagen-I, fibronectin, and tumor necrosis factor (TNF)-alpha-activated fibroblasts. Exosome adhesion to TNF-alpha-activated fibroblasts also triggered integrin-dependent changes in cytosolic calcium, measured by single cell imaging. Thus, B cell-derived exosomes express functional integrins, which are capable of mediating anchorage to ECM and cell-surface adhesion molecules, and may be a novel mode of delivering adhesion signals at distances beyond that of direct cell-cell contact during inflammation.

Activation of SRC tyrosine kinases in response to ICAM-1 ligation in pulmonary microvascular endothelial cells

Previous studies demonstrated that ICAM-1 ligation on human pulmonary microvascular endothelial cells (ECs) sequentially induces activation of xanthine oxidase and p38 MAPK. Inhibition of these signaling events reduces neutrophil migration to the EC borders. This study examined the role of SRC tyrosine kinases in ICAM-1-initiated signaling within these ECs. Cross-linking ICAM-1 on tumor necrosis factor-alpha-pretreated ECs induced an increase in the activity of SRC tyrosine kinases. This increase was inhibited by allopurinol (a xanthine oxidase inhibitor), Me2SO (a hydroxyl radical scavenger), or deferoxamine (an iron chelator). Phenylarsine oxide, a tyrosine phosphatase inhibitor, reduced the base-line activity of SRC as well as the increase in SRC activity induced by ICAM-1 cross-linking. Specific inhibition of the protein expression of the SRC homology 2-containing protein-tyrosine phosphatase-2 (SHP-2) by an antisense oligonucleotide prevented the induced SRC activation but had no effect on the basal SRC activity. Activation of SRC tyrosine kinases was accompanied by tyrosine phosphorylation of ezrin at Tyr-146, which was inhibited by PP2, an SRC tyrosine kinase inhibitor. Moreover, PP2 completely inhibited p38 activation, suggesting a role for SRC tyrosine kinases in p38 activation. These data demonstrate that ICAM-1 ligation activates SRC tyrosine kinases and that this activation requires SHP-2 as well as production of reactive oxygen species generated from xanthine oxidase. Activation of SRC tyrosine kinases in turn leads to tyrosine phosphorylation of ezrin, as well as activation of p38, a kinase previously identified to be required for cytoskeletal changes induced by ICAM-1 ligation and for neutrophil migration along the EC surface.