Lower respiratory tract infections caused by the paramyxoviruses human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) are characterized by short-lasting virus-specific immunity and often long-term airway morbidity, both of which may be the result of alterations in the Ag-presenting function of the lung which follow these infections. In this study, we investigated whether hMPV and RSV experimental infections alter the phenotype and function of dendritic cell (DC) subsets that are recruited to the lung. Characterization of lung DC trafficking demonstrated a differential recruitment of plasmacytoid DC (pDC), conventional DC (cDC), and IFN-producing killer DC to the lung and draining lymph nodes after hMPV and RSV infection. In vitro infection of lung DC indicated that in pDC, production of IFN-alpha, TNF-alpha, and CCL5 was induced only by hMPV, whereas CCL3 and CCL4 were induced by both viruses. In cDC, a similar repertoire of cytokines was induced by hMPV and RSV, except for IFN-beta, which was not induced by RSV. The function of lung pDC was altered following hMPV or RSV infection in vivo, as we demonstrated a reduced capacity of lung pDC to produce IFN-alpha as well as other cytokines including IL-6, TNF-alpha, CCL2, CCL3, and CCL4 in response to TLR9 stimulation. Moreover, we observed an impaired capacity of cDC from infected mice to present Ag to CD4(+) T cells, an effect that lasted beyond the acute phase of infection. Our findings suggest that acute paramyxovirus infections can alter the long-term immune function of pulmonary DC.

Lipin-2 is a member of the lipin family of enzymes, which are key effectors in the biosynthesis of lipids. Mutations in the human lipin-2 gene are associated with inflammatory-based disorders; however, the role of lipin-2 in cells of the immune system remains obscure. In this study, we have investigated the role of lipin-2 in the proinflammatory action of saturated fatty acids in murine and human macrophages. Depletion of lipin-2 promotes the increased expression of the proinflammatory genes Il6, Ccl2, and Tnfα, which depends on the overstimulation of the JNK1/c-Jun pathway by saturated fatty acids. In contrast, overexpression of lipin-2 reduces the release of proinflammatory factors. Metabolically, the absence of lipin-2 reduces the cellular content of triacylglycerol in saturated fatty acid-overloaded macrophages. Collectively, these studies demonstrate a protective role for lipin-2 in proinflammatory signaling mediated by saturated fatty acids that occurs concomitant with an enhanced cellular capacity for triacylglycerol synthesis. The data provide new insights into the role of lipin-2 in human and murine macrophage biology and may open new avenues for controlling the fatty acid-related low grade inflammation that constitutes the sine qua non of obesity and associated metabolic disorders.

Chronic lung infections by Pseudomonas aeruginosa strains are a major cause of morbidity and mortality in cystic fibrosis (CF) patients. Although there is no clear evidence for a primary defect in the immune system of CF patients, the host is generally unable to clear P. aeruginosa from the airways. PTX3 is a soluble pattern recognition receptor that plays nonredundant roles in the innate immune response to fungi, bacteria, and viruses. In particular, PTX3 deficiency is associated with increased susceptibility to P. aeruginosa lung infection. To address the potential therapeutic effect of PTX3 in P. aeruginosa lung infection, we established persistent and progressive infections in mice with the RP73 clinical strain RP73 isolated from a CF patient and treated them with recombinant human PTX3. The results indicated that PTX3 has a potential therapeutic effect in P. aeruginosa chronic lung infection by reducing lung colonization, proinflammatory cytokine levels (CXCL1, CXCL2, CCL2, and IL-1β), and leukocyte recruitment in the airways. In models of acute infections and in in vitro assays, the prophagocytic effect of PTX3 was maintained in C1q-deficient mice and was lost in C3- and Fc common γ-chain-deficient mice, suggesting that facilitated recognition and phagocytosis of pathogens through the interplay between complement and FcγRs are involved in the therapeutic effect mediated by PTX3. These data suggested that PTX3 is a potential therapeutic tool in chronic P. aeruginosa lung infections, such as those seen in CF patients.

Cerebral inflammation as well as systemic immunological alterations has been reported in Alzheimer's disease (AD). We aimed to determine whether spontaneous and mitogen stimulated production of peripheral blood mononuclear cell (PBMC) cytokines, chemokines and chemokine receptors in clinically diagnosed patients with AD were unregulated. PBMC were purified from AD patients and from healthy controls. Supernatants were analyzed for cytokine levels by ELISA methods. mRNA expression was determined by RT-PCR. Expression of chemokine receptors CCR2 and CCR5 was determined by cytofluorimetric analysis. Both CCR5 and CCR2 expression were increased in AD patients respect to control subjects and the expression of CCR2 and CCR5 was more frequent on CD4+ and less frequent on CD8+ cells. Levels of Th1-type cytokine IFNgamma and chemokine RANTES were increased and levels of Th2-type cytokine IL-4 and chemokine MCP-1 were reduced in AD patients compared with those of control subjects. Acetylcholinesterase inhibitor pyridostigmine bromide (AChEI)-therapy reduced CCR2, CCR5, RANTES and IFNgamma expression and production in AD patients. CCR5, CCL5/RANTES, CCL2/MCP-1 and IFNgamma expression and production were increased in PBMC treated with amyloid-beta1-42. Addition of AChEI to PBMC suppresses CCL5/RANTES and IFNgamma. The observed patterns of cyto-chemokine involvement strengthen the questions regarding the inflammatory theory in AD, and raise a pathophysiologic role for selective alteration of cyto-chemokine network.

HIV-associated dementia (HAD) correlates with infiltration of monocytes into the brain. The accessory HIV-1 negative factor (Nef) protein, which modulates several signaling pathways, is constitutively present in persistently infected astroctyes. We demonstrated that monocytes responded with chemotaxis when subjected to cell culture supernatants of nef-expressing astrocytic U251MG cells. Using a protein array, we identified CC chemokine ligand 2/monocyte chemotactic protein-1 (CCL2/MCP-1) as a potential chemotactic factor mediating this phenomenon. CCL2/MCP-1 upregulation by Nef was further confirmed by ribonuclease protection assay, RT-PCR and ELISA. By applying neutralizing antibodies against CCL2/MCP-1 and using CCR2-deficient monocytes, we confirmed CCL2/MCP-1 as the exclusive factor secreted by nef-expressing astrocytes capable of attracting monocytes. Additionally, we showed that Nef-induced CCL2/MCP-1 expression depends on the myristoylation moiety of Nef and requires functional calmodulin. In summary, we suggest that Nef-induced CCL2/MCP-1 expression in astrocytes contributes to infiltration of monocytes into the brain, and thereby to progression of HAD.

OBJECTIVE

To determine cytokine and chemokine concentrations in the tears of patients with dry eye disease (DED) and analyze the possible relationships with the clinical severity of DED.

METHODS

Patients were examined using the Ocular Surface Disease Index, corneal and conjunctival staining, tear breakup time, and impression cytology. They were divided into four groups according to the Dry Eye Workshop severity classification. Tears were collected from 133 patients with DED and 70 healthy controls. Concentrations of cytokines, chemokines, and soluble receptors in collected tear samples were analyzed using current technology with a Human Cytokine/Chemokine kit, a Human Cytokine/Chemokine Panel, and a Human Soluble Cytokine Receptor Panel.

RESULTS

The levels of cytokines interleukin (IL)-1β (P < 0.05), IL-6 (P < 0.001), IL-16 (P < 0.001), IL-33 (P < 0.05), G-CSF (P < 0.001), and transforming growth factor (TGF)-α (P < 0.05) were significantly higher in patients with DED, whereas those of cytokines IL-4 (P < 0.001), IL-12 (p40) (P < 0.001), IL-17A (P < 0.05), and interferon-γ (P < 0.001) were significantly lower. The levels of Fractalkine (chemokine [C-X3-C motif] ligand 1; CX3CL1), MCP-1 (chemokine [C-C motif] ligand 2; CCL2), MIP-1δ (chemokine [C-C motif] ligand 15; CCL15), and ENA-78 (chemokine [C-X-C motif] ligand 5; CXCL5) (P < 0.001, respectively) and soluble receptors, sIL-1RI (P < 0.05), soluble glycoprotein (sgp) 130 (P < 0.05), sIL-6R (P < 0.001), soluble epidermal growth factor receptor (P < 0.05), and soluble tumor necrosis factor receptor 2 (P < 0.001), were higher in patients with DED. There were significant correlations between these molecules and the clinical severity of DED.

CONCLUSIONS

Fifteen molecules were elevated in the tears of patients with DED; four molecules were decreased. Although the levels of sIL-6R, sIL-6R, and sgp130 may be potential indicators of the homeostatic process, an increase in the levels of IL-6 and IL-1 β are the earliest observable changes in patients with DED. Further study on the biomarkers in the pathogenesis of DED and treatment target modalities would be needed.

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly population. We have shown previously that mice deficient in monocyte chemoattractant protein-1 (MCP1/CCL2) or its receptor (CCR2) develop the features of AMD in senescent mice, however, the human genetic evidence so far is contradictory. We hypothesized that any dysfunction in the CCL2 and its receptor result could be the contributing factor in pathogenesis of AMD.

RESULTS

133 AMD patients and 80 healthy controls were enrolled for this study. Single neucleotid Polymorphism for CCL2 and CCR2 was analyzed by real time PCR. CCL2 levels were determined by enzyme-linked immunosorbent assay (ELISA) after normalization to total serum protein and percentage (%) of CCR2 expressing peripheral blood mononuclear cells (PBMCs) was evaluated using Flow Cytometry. The genotype and allele frequency for both CCL2 and CCR2 was found to be significantly different between AMD and normal controls. The CCL2 ELISA levels were significantly higher in AMD patients and flow Cytometry analysis revealed significantly reduced CCR2 expressing PBMCs in AMD patients as compared to normal controls.

CONCLUSIONS

We analyzed the association between single neucleotide polymorphisms (SNPs) of CCL2 (rs4586) and CCR2 (rs1799865) with their respective protein levels. Our results revealed that individuals possessing both SNPs are at a higher risk of development of AMD.

Idiopathic pulmonary fibrosis is characterized by abundant collagen production and accumulation of alternatively activated macrophages (M2) in the lower respiratory tract. Mechanisms as to how alveolar macrophages are activated by collagen breakdown products are unknown. Alveolar macrophages were obtained by bronchoalveolar lavage from 30 patients with idiopathic pulmonary fibrosis (IPF) and 37 healthy donors (HD). Alveolar macrophages were cultured in the presence of collagen type I, III, IV and V monomers w/wo a neutralizing antibody against scavenger receptor I class A (CD204). Culture supernatants were assayed for the M2 markers CCL18, CCL2, and interleukin-1 receptor antagonist (IL-1ra) by ELISA. Furthermore, expression of phospho-Akt was measured using ELISA and expression of CD204 by RT-PCR and flow cytometry. Stimulation with collagen type I and III monomers significantly up-regulated CCL18, IL-1ra production of alveolar macrophages. Furthermore, expression of CCL2 and CD204 were up-regulated by collagen type I exposure. In addition, collagen type I stimulation increased pospho-Akt expression. Collagen type I effects were abrogated by neutralizing antiCD204 and a non-selective Phosphatidylinositide 3-kinase inhibitor (LY294002). Spontaneous CD204 expression of alveolar macrophages was significantly increased in patients with IPF. In conclusion, our findings demonstrate that monomeric collagen type I via CD204 induces phospho-Akt expression shifting alveolar macrophages to the profibrotic M2 type. Innate immune responses induced by collagen monomers might perpetuate pulmonary fibrosis.

Endurance exercise is associated with significant improvements in cardio-metabolic risk parameters. A role for myokines has been hypothesized, yet limited information is available about myokines induced by acute endurance exercise in humans. Therefore, the aim of the study was to identify novel exercise-induced myokines in humans. To this end, we carried out a 1 h one-legged acute endurance exercise intervention in 12 male subjects and a 12 wk exercise training intervention in 18 male subjects. Muscle biopsies were taken before and after acute exercise or exercise training and were subjected to microarray-based analysis of secreted proteins (secretome). For acute exercise, secretome analysis resulted in a list of 86 putative myokines, which was reduced to 29 by applying a fold-change cut-off of 1.5. Based on that shortlist, a selection of putative myokines was measured in the plasma by ELISA or multiplex assay. From that selection, CX3CL1 (fractalkine) and CCL2 (MCP-1) increased at both mRNA and plasma levels. From the known myokines, only IL-6 and FGF 21 changed at the mRNA level, whereas none of the known myokines changed at the plasma level. Secretome analysis of exercise training intervention resulted in a list of 69 putative myokines. Comparing putative myokines altered by acute exercise and exercise training revealed a limited overlap of only 13 genes. In conclusion, this study identified CX3CL1 and CCL2 as myokines that were induced by acute exercise at the gene expression and plasma level and that may be involved in communication between skeletal muscle and other organs.

17β-Estradiol (E2) treatment limits the pathology associated with pulmonary diseases caused by pathogens, allergens, and asthma, partly by reducing the production of proinflammatory cytokines and chemokines. To test the hypothesis that E2 protects against influenza A virus (IAV) infection by altering the recruitment and activity of innate immune cells and T cells, chemokine concentrations were measured and innate and adaptive immune cells were enumerated from the lungs of E2- and placebo-treated ovariectomized female C57BL/6 mice following infection. Females treated with E2 experienced less morbidity but had similar lung virus titers to placebo-treated females. Females treated with E2 had lower induction of CCL2 but higher CCL3 and CXCL1 responses in their lungs than placebo-treated females. Pulmonary recruitment of neutrophils, NK cells, macrophages, and dendritic cells was increased following infection, but only neutrophil numbers were greater in E2-treated than placebo-treated females. Neutrophils enhance the responses of influenza virus-specific CD8 T cells to promote virus clearance and improve the outcome of infection. Total numbers of virus-specific CD8 T cells were not altered by treatment with E2, but the proportion of gamma interferon (IFN-γ)- and tumor necrosis factor alpha (TNF-α)-producing, virus-specific CD8 T cells was increased. Neutrophil depletion in E2-treated females increased morbidity, reduced pulmonary production of chemoattractants for neutrophils, and reduced IFN-γ production by virus-specific CD8 T cells. Neutrophils mediate both inflammation and tissue repair during IAV infection and are regulated by E2 to improve the outcome of influenza in females.

OBJECTIVE

Severe influenza is associated with excessive inflammation that leads to tissue damage. We demonstrate that estradiol (E2) is a potent anti-inflammatory hormone that reduces the severity of influenza A virus infection in females. Treatment of female C57BL/6 mice with E2 does not affect virus replication but rather alters the production of chemokines, pulmonary recruitment of neutrophils, and the cytokine responses of virus-specific CD8 T cells to protect females against severe influenza.

The novel interleukin (IL)-1 family cytokine IL-33 has been shown to activate T helper 2 (Th2) lymphocytes, mast cells and basophils to produce an array of proinflammatory cytokines, as well as to mediate blood eosinophilia, IgE secretion and hypertrophy of airway epithelium in mice. In the present study, we characterized the activation of human eosinophils by IL-33, and investigated the underlying intracellular signaling mechanisms. IL-33 markedly enhanced eosinophil survival and upregulated cell surface expression of the adhesion molecule intercellular adhesion molecule (ICAM)-1 on eosinophils, but it suppressed that of ICAM-3 and L-selectin. In addition, IL-33 mediates significant release of the proinflammatory cytokine IL-6 and the chemokines CXCL8 and CCL2. We found that IL-33-mediated enhancement of survival, induction of adhesion molecules, and release of cytokines and chemokines were differentially regulated by activation of the nuclear factor (NF)-kappaB, p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways. Furthermore, we compared the above IL-33 activities with two structurally and functionally related cytokines, IL-1beta and IL-18. IL-1beta, but not IL-18, markedly upregulated cell surface expression of ICAM-1. IL-1beta and IL-18 also significantly enhanced eosinophil survival, and induced the release of IL-6 and chemokines CXCL8 and CCL2 via the activation of the NF-kappaB, p38 MAPK and ERK pathways. Synergistic effects on the release of IL-6 were also observed in combined treatment with IL-1beta, IL-18 and IL-33. Taken together, our findings provide insight into IL-33-mediated activation of eosinophils via differential intracellular signaling cascades in the immunopathogenesis of allergic inflammation.

BACKGROUND

The expression of the recently cloned histamine H(4) receptor (H(4)R) by leukocytes suggests a role in immunomodulation.

OBJECTIVE

The expression and function of the H(4)R on human monocytes obtained from peripheral blood was investigated.

METHODS

H(4)R expression was studied by using flow cytometry. Effects of H(4)R stimulation on Ca(2+) mobilization was determined fluorometrically, CCL2 production was determined by means of ELISA, intracellular CCL2 staining was measured with flow cytometry, and CCL2 mRNA was measured by using real-time quantitative LightCycler PCR. The relevance of CCL2 production was determined in chemotaxis transmigration assays.

RESULTS

H(4)R protein was expressed by monocytes and upregulated by IFN-gamma. H(4)R agonists (clobenpropit and 4-methylhistamine) induce a Ca(2+) mobilization in monocytes, which could be blocked with the selective H(4)R antagonist JNJ7,777,120. Furthermore, H(4)R agonists downregulated CCL2 protein production. This effect could also be blocked by JNJ7,777,120. Supernatants of H(4)R agonist-stimulated monocytes attracted less monocytes in transmigration assays. The downregulation of CCL2 production was regulated at different levels. First, the synthesis of CCL2 mRNA was significantly decreased. Second, intracellular staining suggested an inhibition of CCL2 secretion after stimulation with H(4)R agonists.

CONCLUSIONS

Human monocytes express the H(4)R, and its stimulation leads to a Ca(2+) influx and an inhibition of CCL2 production, resulting in a reduction of monocyte recruitment.

CONCLUSIONS

The H(4)R could represent an important anti-inflammatory receptor on monocytes and could be an interesting target for drug development.

Monocyte infiltration is an important pathogenic event in human immunodeficiency virus type one (HIV-1) associated dementia (HAD). CXCL8 (Interleukin 8, IL-8), a CXC chemokine that elicits chemotaxis of neutrophils, has recently been found to recruit monocytes or synergistically enhance CCL2-mediated monocyte migration. In this report, we demonstrate CXCL8 levels in the cerebrospinal fluid of HAD patients are higher than HIV-1 seropositive patients without neurological impairment. The underlying mechanisms regulating CXCL8 production during disease are not completely understood. We investigated the role of HIV-1-infected and immune-competent macrophages, the principal target cell and mediator of neuronal injury in HAD, in regulating astrocyte CXCL8 production. Immune-activated and HIV-1-infected human monocyte-derived-macrophages (MDM) conditioned media (MCM) induced production of CXCL8 by human astrocytes. This CXCL8 production was dependent on MDM IL-1beta and TNF-alpha production following viral and immune activation. CXCL8 production was reduced by inhibitors for mitogen-activated protein kinases (MAPKs), including p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinases (ERK1/2). Moreover, prolonged IL-1beta or TNF-alpha treatment activated double-stranded RNA-activated protein kinase (PKR). Inhibition of PKR prevented elevated CXCL8 production in astrocytes. We conclude that IL-1beta and TNF-alpha, produced from HIV-1-infected and immune-competent macrophages, are critical in astrocyte CXCL8 production. Multiple protein kinases, including p38, JNK, ERK1/2, and PKR, participate in the inflammatory response of astrocytes. These observations will help to identify effective therapeutic strategies to reduce high-levels of CXCL8-mediated CNS inflammation during HAD.

Quercetin, a member of the flavonoid family, is one of the most prominent dietary antioxidants. This study investigates the mechanisms for the effects of quercetin on cultured human RPE cells and in Ccl2/Cx3cr1 double knock-out (DKO) mice, which spontaneously develop progressive retinal lesions mimicking age-related macular degeneration (AMD). In the in vitro experiment, cultured ARPE-19 cells were exposed to 1 mM H(2)O(2) with or without 50 muM quercetin for 2 h. Cellular viability, mitochondrial function, and apoptosis were assessed using crystal violet staining, MTT assay, and comet assay, respectively. Apoptotic molecular transcripts of BCL-2, BAX, FADD, CASPASE-3 and CASPASE-9 were measured by RQ-PCR. COX activity and nitric oxide (NO) level were determined in the supernatant of the culture medium. Quercetin treatment protected ARPE-19 cells from H(2)O(2)-induced oxidative injury, enhanced BCL-2 transcript levels, increased the BCL-2/BAX ratio, suppressed the transcription of pro-apoptotic factors such as BAX, FADD, CASPASE-3 and CASPASE-9, inhibited the transcription of inflammatory factors such as TNF-alpha, COX-2 and INOS, and decreased the levels of COX and NO in the culture medium. In the in vivo experiment, DKO and C57/B6 mice were treated with 25 mg/kg/day quercetin by intraperitoneal injection daily for two months. Funduscopy was performed monthly. After two months, serum was collected to measure NADP(+)/NADPH, COX, PGE-2, and NO levels. The eyes were harvested for histology and A2E measurement. Ocular transcripts of Bcl-2, Bax, Cox-2, Inos, Tnf-alpha, Fas, FasL and Caspase-3 were detected by RQ-PCR. Quercetin treatment did not reverse the progression of retinal lesions in DKO mice funduscopically or histologically. Although quercetin treatment could recover systemic anti-oxidative capacity, suppress the systemic expression of NO, COX and PGE-2, and decrease ocular A2E levels, it could not effectively suppress the transcripts of the ocular inflammatory factors Tnf-alpha, Cox-2 and Inos, or the pro-apoptotic factors Fas, FasL and Caspase-3 in DKO mice. Our data demonstrate that quercetin can protect human RPE cells from oxidative stress in vitro via inhibition of pro-inflammatory molecules and direct inhibition of the intrinsic apoptosis pathway. However, quercetin (25 mg/kg/day) does not improve the retinal AMD-like lesions in the Ccl2(-/-)/Cx3cr1(-/-) mice, likely due to its insufficient suppression of the inflammatory and apoptosis pathways in the eye.

Rationale: Focused ultrasound (FUS), in conjunction with circulating microbubbles (MBs), can be used to transiently increase the permeability of the blood-brain barrier (BBB) in a targeted manner, allowing therapeutic agents to enter the brain from systemic circulation. While promising preclinical work has paved the way for the initiation of 3 human trials, there remains concern regarding neuroinflammation following treatment. The aim of this study was to assess the magnitude of this response following sonication and explore the influence of MB dose. Methods: Differential expression of NFκB signaling pathway genes was assessed in rats at 6 h and 4 days following a FUS-mediated increase in BBB permeability. Three sonication schemes were tested: (1) a clinical imaging dose of MBs + peak negative pressure (PNP) controlled by acoustic feedback, (2) 10x clinical imaging dose of MBs + constant PNP of 0.290 MPa, and (3) 10x clinical imaging dose of MBs + PNP controlled by acoustic feedback. Follow-up magnetic resonance imaging (MRI) was performed to assess edema and hemorrhage. Hematoxylin and eosin histology was used to evaluate general tissue health. Results: MB dose has a significant impact on the expression of several key genes involved in acute inflammation and immune activation, including Tnf, Birc3, and Ccl2. At a clinical imaging dose of MBs, there were no significant changes detected in the expression of any NFκB signaling pathway genes. Conversely, a high MB dose resulted in a clear activation of the NFκB signaling pathway, accompanied by edema, neuronal degeneration, neutrophil infiltration, and microhemorrhage. Results also suggest that post-FUS gadolinium enhancement may hold predictive value in assessing the magnitude of inflammatory response. Conclusion: While a significant and damaging inflammatory response was observed at high MB doses, it was demonstrated that FUS can be used to induce increased BBB permeability without an associated upregulation of NFκB signaling pathway gene expression. This emphasizes the importance of employing optimized FUS parameters to mitigate the chances of causing injury to the brain at the targeted locations.

Mast cells and macrophages infiltrate healing myocardial infarcts and may play an important role in regulating fibrous tissue deposition and extracellular matrix remodelling. This study examined the time-course of macrophage and mast cell accumulation in healing infarcts and studied the histological characteristics and protease expression profile of mast cells in a canine model of experimental infarction. Although macrophages were more numerous than mast cells in infarct granulation tissue, macrophage density decreased during maturation of the scar, whereas mast cell numbers remained persistently elevated. During the inflammatory phase of infarction, newly recruited leucocytes infiltrated the injured myocardium and appeared to be clustered in close proximity to degranulating cardiac mast cells. During the proliferative phase of healing, mast cells had decreased granular content and were localized close to infarct neovessels. In contrast, macrophages showed no selective localization. Mast cells in healing canine infarcts were alcian blue/safranin-positive cells that expressed both tryptase and chymase. In order to explain the pro-inflammatory and angiogenic actions of tryptase--the major secretory protein of mast cells--its effects on endothelial chemokine expression were examined. Chemokines are chemotactic cytokines that play an important role in leucocyte trafficking and angiogenesis and are highly induced in infarcts. Tryptase, a proteinase-activated receptor (PAR)-2 agonist, induced endothelial expression of the angiogenic chemokines CCL2/MCP-1 and CXCL8/IL-8, but not the angiostatic chemokine CXCL10/IP-10. Endothelial PAR-2 stimulation with the agonist peptide SLIGKV induced a similar chemokine expression profile. Mast cell tryptase may exert its angiogenic effects in part through selective stimulation of angiogenic chemokines.

HIV-infected individuals have activated monocytes with an IFNα phenotype and elevated levels of circulating LPS. These individuals also have a risk of premature cardiovascular disease. The effect of activated monocyte exosomes (Exos) on endothelial cells is unknown. To determine whether Exos from immune-activated monocytes could alter endothelial cell expression and contribute to monocyte/macrophage transmigration and adhesion, we isolated Exos from monocytes stimulated with IFNα, LPS, or both (I/L). We show that monocyte Exos contain different inflammatory microRNA cargo depending on stimulation. When LPS Exos or I/L Exos were added to HUVECs, we found a significant increase in adhesion molecule ICAM-1, chemokine ligand (CCL)-2, and cytokine IL-6 mRNAs and proteins compared with cells treated with IFNα Exos or Exos derived from unstimulated monocytes. Inhibition of transcription factor NF-κB, a common inflammatory cytokine pathway, prevented induction of CCL2, IL6, and ICAM1 Inhibition of TLR4 resulted in differential blockage of the targets. Our results demonstrate for the first time that primary human monocyte Exos enter endothelial cells and cause dysfunction via the TLR4 and NF-κB pathways, which may contribute to heart disease in HIV infection and other diseases involving chronic immune activation.-Tang, N., Sun, B., Gupta, A., Rempel, H., Pulliam, L. Monocyte exosomes induce adhesion molecules and cytokines via activation of NF-κB in endothelial cells.

The purpose of this study was to analyze the expression of the two proinflammatory cytokines IL-20 and IL-24 and their shared receptors in rheumatoid arthritis and spondyloarthropathy. IL-20 was increased in plasma of rheumatoid arthritis patients compared with osteoarthritis patients and IL-24 was increased in synovial fluid and plasma of rheumatoid arthritis and spondyloarthropathy patients compared with osteoarthritis patients. IL-20 and IL-24 mRNA was only present at low levels in the synovium. In the synovial membrane, IL-20 protein was present in mononuclear cells and neutrophil granulocytes whereas IL-24 protein was observed in endothelial cells and mononuclear cells. IL-20 receptor type 1 and IL-22 receptor were expressed by granulocytes in the synovial fluid. In synovial fluid mononuclear cell cultures, stimulation with recombinant human IL-20 or recombinant human IL-24 induced monocyte chemoattractant protein 1 (CCL2/MCP-1) secretion, but not tumour necrosis factor alpha mRNA synthesis or IL-6 secretion. Both IL-20 and IL-24 showed correlations to CCL2/MCP-1 in plasma from rheumatoid arthritis and spondyloarthropathy patients. This study associates IL-20 and IL-24 to the synovium of rheumatoid arthritis and spondyloarthropathy and results indicate that the two cytokines contribute to disease pathogenesis through recruitment of neutrophil granulocytes and induction of CCL2/MCP-1.

Activation of c-Jun amino kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and the transcription factor nuclear factor-κB (NF-κB) drives renal inflammation and fibrosis. However, the upstream MAP kinase kinase kinase (MAP3K) enzyme(s) that activate these pathways in kidney disease are unknown. We determined the role of one candidate MAP3K enzyme, transforming growth factor-β1-activated kinase-1 (TAK1/ MAP3K7), in activation of JNK, p38, and NF-κB in the obstructed kidney using conditional gene deletion in adult mice, and assessed the potential protective effect of TAK1 deletion on renal pathology. TAK1 deletion in cultured tubular epithelial cells substantially inhibited IL-1 and TNF-α-induced JNK, p38, and NF-κB signaling and the proinflammatory response. Map3k7(f/f)Cre-ER(TM) mice (in which tamoxifen induces global TAK1 deletion) and control Map3k7(f/f) mice were given tamoxifen at the time of unilateral ureteric obstruction (UUO) and then killed 2, 4, or 5 days later. Tamoxifen-treated control Map3k7(f/f) mice showed the expected activation of JNK, p38, and NF-κB signaling on days 2, 4, and 5, with macrophage infiltration and upregulation of mRNA levels of proinflammatory molecules (IL-1α, TNF-α, NOS2, and CCL2). Control Map3k7(f/f) mice also showed interstitial myofibroblast accumulation and collagen deposition in the obstructed kidney. Tamoxifen treatment of Map3k7(f/f)Cre-ER(TM) mice caused a 60% reduction in renal TAK1 expression on day 4 and >80% on day 5 UUO. Coincident with TAK1 deletion, activation of JNK, p38, and NF-κB signaling was markedly suppressed on days 4 to 5 UUO, which halted renal macrophage accumulation and expression of proinflammatory molecules. TAK1 deletion also halted the development of renal fibrosis in terms of myofibroblast accumulation, collagen deposition, and expression of profibrotic molecules. In conclusion, these studies establish TAK1 as a major upstream activator of JNK, p38, and NF-κB signaling in the obstructed kidney, and they define a pathologic role for TAK1 in renal inflammation and fibrosis.

Gaucher disease causes pathologic skeletal changes that are not fully explained. Considering the important role of mesenchymal stromal cells (MSCs) in bone structural development and maintenance, we analyzed the cellular biochemistry of MSCs from an adult patient with Gaucher disease type 1 (N370S/L444P mutations). Gaucher MSCs possessed a low glucocerebrosidase activity and consequently had a 3-fold increase in cellular glucosylceramide. Gaucher MSCs have a typical MSC marker phenotype, normal osteocytic and adipocytic differentiation, growth, exogenous lactosylceramide trafficking, cholesterol content, lysosomal morphology, and total lysosomal content, and a marked increase in COX-2, prostaglandin E2, interleukin-8, and CCL2 production compared with normal controls. Transcriptome analysis on normal MSCs treated with the glucocerebrosidase inhibitor conduritol B epoxide showed an up-regulation of an array of inflammatory mediators, including CCL2, and other differentially regulated pathways. These cells also showed a decrease in sphingosine-1-phosphate. In conclusion, Gaucher disease MSCs display an altered secretome that could contribute to skeletal disease and immune disease manifestations in a manner distinct and additive to Gaucher macrophages themselves.

OBJECTIVE

Chemokines are soluble mediators involved in angiogenesis, cellular growth control and immunomodulation. In the present study we investigated the effects of various chemokines on proliferation of acute myelogenous leukemia (AML) cells and constitutive chemokine release by primary AML cells.

METHODS

Native human AML cells derived from 68 consecutive patients were cultured in vitro. We investigated AML cell proliferation (3H-thymidine incorporation, colony formation), chemokine receptor expression, constitutive chemokine release and chemotaxis of normal peripheral blood mononuclear cells.

RESULTS

Exogenous chemokines usually did not have any effect on AML blast proliferation in the absence of hematopoietic growth factors, but when investigating growth factor-dependent (interleukin 3 + granulocyte-macrophage colony-stimulating factor + stem cell factor) proliferation in suspension cultures the following patient subsets were identified: (i) patients whose cells showed chemokine-induced growth enhancement (8 patients); (ii) divergent effects on proliferation (15 patients); and (iii) no effect (most patients). These patient subsets did not differ in chemokine receptor expression, but, compared to CD34- AML cells, CD34+ cells showed higher expression of several receptors. Chemokines also increased the proliferation of clonogenic AML cells from the first subset of patients. Furthermore, a broad constitutive chemokine release profile was detected for most patients, and the following chemokine clusters could be identified: CCL2-4/CXCL1/8, CCL5/CXCL9-11 (possibly also CCL2CCL2-4/CXCL1/8 cluster showed significant correlations between corresponding mRNA levels and NFkB levels/activation. The chemotaxis of normal immunocompetent cells for patients without constitutive chemokine release was observed to be decreased.

CONCLUSIONS

Differences in chemokine responsiveness as well as chemokine release contribute to patient heterogeneity in AML. Patients with AML can be classified into distinct subsets according to their chemokine responsiveness and chemokine release profile.

OBJECTIVE

Significant progress has been made in critical care medicine during the past several decades. However, the mortality rate is still high in patients with sepsis, especially with acute kidney injury (AKI). Mesenchymal stem cells (MSCs) possess an ability to ameliorate renal injury from ischemia-reperfusion, but it is still unknown whether they have the ability to reduce sepsis-associated AKI.

METHODS

Male C57BL/6 mice underwent cecal ligation and puncture operation to induce sepsis and then received either normal saline or MSCs (1 × 10 cells intravenously) 3 h after surgery.

RESULTS

Within 24 h after cecal ligation and puncture operation, the septic mice developed kidney injury and exhibited a higher mortality. Treatment with MSCs decreased serum creatinine and blood urea nitrogen levels and improved recovery of tubular function. mRNA levels of interleukin 6 (IL-6), IL-17, tumor necrosis factor α, interferon γ, CXCL1, CXCL2, CXCL5, CCL2, and CCL3 in kidney tissue were dramatically decreased after MSC treatment. Neutrophil infiltration in kidney and blood bacterial loads were attenuated after MSC injection. Moreover, mice treated with MSCs had a higher survival rate than the saline treatment group. Injected MSCs were mainly localized in the lungs, spleen, and abdominal cavity lymph node, but not in the kidneys.

CONCLUSIONS

Treatment with MSCs can alleviate sepsis-associated AKI and improve survival in mice with polymicrobial sepsis. These effects may be mediated by the inhibition of IL-17 secretion and balance of the proinflammatory and anti-inflammatory states. Mesenchymal stem cells may be a potential new therapeutic agent for the prevention or reduction of sepsis-associated AKI.

Inflammation marks all stages of atherogenesis. DNA hypermethylation in the whole genome or specific genes is associated with inflammation and cardiovascular diseases. Therefore, we aimed to study whether inhibiting DNA methylation by DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) ameliorates atherosclerosis in low-density lipoprotein receptor knockout (Ldlr(-/-)) mice. Ldlr(-/-) mice were fed an atherogenic diet and adminisered saline or 5-aza-dC (0.25 mg/kg) for up to 30 weeks. 5-aza-dC treatment markedly decreased atherosclerosis development in Ldlr(-/-) mice without changes in body weight, plasma lipid profile, macrophage cholesterol levels and plaque lipid content. Instead, this effect was associated with decreased macrophage inflammation. Macrophages with 5-aza-dC treatment had downregulated expression of genes involved in inflammation (TNF-α, IL-6, IL-1β, and inducible nitric oxidase) and chemotaxis (CD62/L-selectin, chemokine [C-C motif] ligand 2/MCP-1 [CCL2/MCP-1], CCL5, CCL9, and CCL2 receptor CCR2). This resulted in attenuated macrophage migration and adhesion to endothelial cells and reduced macrophage infiltration into atherosclerotic plaques. 5-aza-dC also suppressed macrophage endoplasmic reticulum stress, a key upstream signal that activates macrophage inflammation and apoptotic pathways. Finally, 5-aza-dC demethylated liver X receptor α (LXRα) and peroxisome proliferator-activated receptor γ1 (PPARγ1) promoters, which are both enriched with CpG sites. This led to overexpression of LXRα and PPARγ, which may be responsible for 5-aza-dC's anti-inflammatory and atheroprotective effect. Our findings provide strong evidence that DNA methylation may play a significant role in cardiovascular diseases and serve as a therapeutic target for prevention and treatment of atherosclerosis.

Monocyte chemotactic protein-1 (MCP-1) (also referred to as chemokine (C-C motif) ligand 2 (CCL2) is expressed by mainly inflammatory cells and endothelial cells. The expression level is upregulated after proinflammatory stimuli and tissue injury which are associated with atherosclerotic lesion. Atherosclerosis is a progressive disease starting with accumulation of lipids, lipoproteins, and immune cells in the arterial wall. MCP-1 has been reported to play an important role in the pathogenesis of atherosclerosis and considerable evidence supports that the monocyte containing MCPs and macrophage influences the growth of other cell types within the atherosclerotic lesion. This review will focus on the general structure features of MCP-1 and its role in atherosclerosis.