Malarial pigment does not induce MMP-2 and TIMP-2 protein release by human monocytes

Dear editor, In the recent years growing evidence on the involvement of human matrix metalloproteinases(MMPs) and tissue inhibitors of metalloproteinases(TIMPs) in cerebral malaria (CM) has been reported[1]and a role for malarial pigment haemozoin(HZ) has been proposed[2,3].In a recent work my group showed that in human microvascular endothelial

Inhibition of matrix metalloproteinase-9 secretion by dimethyl sulfoxide and cyclic adenosine monophosphate in human monocytes

BACKGROUND Matrix metalloproteinases(MMPs),including MMP-9,are an integral part of the immune response and are upregulated in response to a variety of stimuli.New details continue to emerge concerning the mechanistic and regulatory pathways that mediate MMP-9 secretion.There is significant evidence for regulation of inflammation by dimethyl sulfoxide(DMSO)and 3',5'-cyclic adenosine monophosphate(cAMP),thus investigation of how these two molecules may regulate both MMP-9 and tumor necrosis factorα(TNFα)secretion by human monocytes was of high interest.The hypothesis tested in this study was that DMSO and cAMP regulate MMP-9 and TNFαsecretion by distinct mechanisms.AIM To investigate the regulation of lipopolysaccharide(LPS)-stimulated MMP-9 and tumor necrosis factorαsecretion in THP-1 human monocytes by dimethyl sulfoxide and cAMP.METHODS The paper describes a basic research study using THP-1 human monocyte cells.All experiments were conducted at the University of Missouri-St.Louis in the Department of Chemistry and Biochemistry.Human monocyte cells were grown,cultured,and prepared for experiments in the University of Missouri-St.Louis Cell Culture Facility as per accepted guidelines.Cells were treated with LPS for selected exposure times and the conditioned medium was collected for analysis of MMP-9 and TNFαproduction.Inhibitors including DMSO,cAMP regulators,and anti-TNFαantibody were added to the cells prior to LPS treatment.MMP-9 secretion was analyzed by gel electrophoresis/western blot and quantitated by ImageJ software.TNFαsecretion was analyzed by enzyme-linked immuno sorbent assay.All data is presented as the average and standard error for at least 3 trials.Statistical analysis was done using a two-tailed paired Student t-test.P values less than 0.05 were considered significant and designated as such in the Figures.LPS and cAMP regulators were from Sigma-Aldrich,MMP-9 standard and antibody and TNFαantibodies were from R&D Systems,and amyloid-βpeptide was from rPeptide.RESULTS In our investigation of MMP-9 secretion from THP-1 human monocytes,we made the following findings.Inclusion of DMSO in the cell treatment inhibited LPSinduced MMP-9,but not TNFα,secretion.Inclusion of DMSO in the cell treatment at different concentrations inhibited LPS-induced MMP-9 secretion in a dosedependent fashion.A cell-permeable cAMP analog,dibutyryl cAMP,inhibited both LPS-induced MMP-9 and TNFαsecretion.Pretreatment of the cells with the adenylyl cyclase activator forskolin inhibited LPS-induced MMP-9 and TNFαsecretion.Pretreatment of the cells with the general cAMP phosphodiesterase inhibitor IBMX reduced LPS-induced MMP-9 and TNFαin a dose-dependent fashion.Pre-treatment of monocytes with an anti-TNFαantibody blocked LPSinduced MMP-9 and TNFαsecretion.Amyloid-βpeptide induced MMP-9 secretion,which occurred much later than TNFαsecretion.The latter two findings strongly suggested an upstream role for TNFαin mediating LPS-stimulate MMP-9 secretion.CONCLUSION The cumulative data indicated that MMP-9 secretion was a distinct process from TNFαsecretion and occurred downstream.First,DMSO inhibited MMP-9,but not TNFα,suggesting that the MMP-9 secretion process was selectively altered.Second,cAMP inhibited both MMP-9 and TNFαwith a similar potency,but at different monocyte cell exposure time points.The pattern of cAMP inhibition for these two molecules suggested that MMP-9 secretion lies downstream of TNFαand that TNFαmay a key component of the pathway leading to MMP-9 secretion.This temporal relationship fit a model whereby early TNFαsecretion directly led to later MMP-9 secretion.Lastly,antibody-blocking of TNFαdiminished MMP-9 secretion,suggesting a direct link between TNFαsecretion and MMP-9 secretion.

cFLIPS regulates alternative NLRP3 inflammasome activation in human monocytes

The innate immune responses,including inflammasome activation,are paramount for host defense against pathogen infection.In contrast to canonical and noncanonical inflammasome activation,in this study,heat-killed gram-negative bacteria(HK bacteria)were identified as single-step stimulators of the NLRP3 inflammasome in human monocytes,and they caused a moderate amount of IL-1βto be released from cells.Time course experiments showed that this alternative inflammasome response was finished within a few hours.Further analysis showed that the intrinsically limited NLRP3 inflammasome activation response was due to the negative regulation of caspase-8 by the short isoform of cFLIP(cFLIPs),which was activated by NF-κB.In contrast,overexpressed cFLIPS,but not overexpressed cFLIPL,inhibited the activation of caspase-8 and the release of IL-1βin response to HK bacteria infection in human monocytes.Furthermore,we demonstrated that TAK1 activity mediated the expression of cFLIPs and was upstream and essential for the caspase-8 cleavage induced by HK bacteria in human monocytes.The functional specificity of cFLIPs and TAK1 revealed unique responses of human monocytes to a noninvasive pathogen,providing novel insights into an alternative regulatory pathway of NLRP3 inflammasome activation.

Mass spectrometry based proteomics profiling of human monocytes

Human monocyte is an important cell type which is involved in various complex human diseases. To better understand the biology of human monocytes and facilitate further studies, we developed the first comprehensive proteome knowledge base specifically for human monocytes by integrating both in vivo and in vitro datasets. The top 2000 expressed genes from in vitro datasets and 779 genes from in vivo experiments were integrated into this study. Altogether, a total of 2237 unique monocyte-expressed genes were cataloged. Biological functions of these monocyte-expressed genes were annotated and classified via Gene Ontology （GO） analysis. Furthermore, by extracting the overlapped genes from in vivo and in vitro datasets, a core gene list including 541 unique genes was generated. Based on the core gene list, further gene-disease associations, pathway and network analyses were performed. Data analyses based on multiple bioinformatics tools produced a large body of biologically meaningful information, and revealed a number of genes such as SAMHDI, G6PD, GPD2 and EN01, which have been reported to be related to immune response, blood biology, bone remodeling, and cancer respectively. As a unique resource, this study can serve as a reference map for future in-depth research on monocytes biology and monocyte-involved human diseases.

The First Reported Case of Human Monocytic Ehrlichiosis (HME) in Jordan

Human Ehrlichiosis infrequently occurs and can be missed, but attention to history and a meticulous physical examination would raise the index for suspicion and is documented with proper investigations. We report the first case of human monocytic Ehrlichiosis (HME) in a young female patient who lives in the Suburb city of Madaba, Jordan. She presented with fever, severe headache, skin rash, and confusion. She rapidly deteriorated and was admitted to our hospital. She had arrhythmias, convulsions, lapsed into a coma and respiratory failure and needed non-invasive ventilation. In addition to her clinical and epidemiological characteristics, the diagnosis was confirmed by the buffy coat. She had a swift response to oral doxycycline and was discharged home.

Short-chain fatty acids act as antiinflammatory mediators by regulating prostaglandin E_2 and cytokines

AIM： To investigate the effect of short-chain fatty acids （SCFAs） on production of prostaglandin E2 （PGE2）, cytokines and chemokines in human monocytes. METHODS： Human neutrophils and monocytes were isolated from human whole blood by using 1-Step Polymorph and RosetteSep Human Monocyte Enrichment Cocktail, respectively. Human GPR41 and GPR43 mRNA expression was examined by quantitative realtime polymerase chain reaction, The calcium flux assay was used to examine the biological activities of SCFAs in human neutrophils and monocytes. The effect of SCFAs on human monocytes and peripheral blood mononuclear cells （PBMC） was studied by measuring PGE2, cytokines and chemokines in the supernatant. The effect of SCFAs in vivo was examined by intraplantar injection into rat paws. RESULTS： Human GPR43 is highly expressed in human neutrophils and monocytes. SCFAs induce robust calcium flux in human neutrophils, but not in human monocytes. In this study, we show that SCFAs can induce human monocyte release of PGE2 and that this effect can be enhanced in the presence of lipopolysaccharide （LPS）. In addition, we demonstrate that PGE2 production induced by SCFA was inhibited by pertussis toxin, suggesting the involvement of a receptor-mediated mechanism. Furthermore, SCFAs can specifically inhibit constitutive monocyte chemotactic protein-1 （MCP-1） production and LPS-induced interleukin-10 （IL-10） production in human monocytes without affecting the secretion of other cytokines and chemokines examined. Similar activities were observed in human PBMC for the release of PGE2, MCP-1 and IL-10 after 5CFA treatment. In addition, SCFAs inhibit LPS-induced production of tumor necrosis factor-α and interferon-7 in human PBIVlC. Finally, we show that SCFAs and LPS can induce PGE2 production in vivo by intraplantar injection into rat paws （P 〈 0.01）. CONCLUSION： SCFAs can have distinct antiinflammatory activities due to their regulation of PGE2, cytokine and chemokine release from human immune cells.

Effect of Early Intensive Insulin Therapy on Immune Function of Aged Patients with Severe Trauma

This study examined the effect of intensive insulin therapy on immune function and inflammatory factors at the early phase after severe trauma. At day 1, 3, 5, 7 after admission, subsets of CD4＋ helper T lymphocytes （Th1/Th2） and human leukocyte antigen （HLA）-DR expression on CD14＋ monocytes were flow cytometrically measured. Levels of cytokines, including tumor necrosis factor-alpha （TNF-α）, interleukin-6 （IL-6）, interleukin-10 （IL-10） and other immunity markers, such as IgA, IgG, IgM, C3, C4 and C reaction protein （CRP） were examined in two groups. The results showed that TNF-α, IL-6 and CRP levels in the intensive insulin therapy group were significantly lower than those in the conventional therapy group, whereas IL-10 levels were substantially increased after intensive insulin therapy. C3 level at day 3, 5, 7 and C4 levels at day 5, 7 were lower in the intensive therapy group than in the conventional therapy group. Th1/Th2 ratios decreased gradually over time in both groups, and were much lower at day 3, 5, 7 in intensive therapy group. There were significant differences among day 3 to day 7 after admission in HLA-DR expression in CD14＋ monocytes. It was concluded that the intensive insulin therapy could decrease pro-inflammatory cytokines and increase anti-inflammatory cytokines in the elderly suffering from severe trauma, at the same time, with complement recovery being delayed. Moreover, intensive insulin therapy promoted immune suppression and, therefore, measures need be taken to address the issue.

PHENOTYPIC CHARACTERISTICS OF HUMAN BLOOD MONOCYTE SUBPOPULATIONS IN PSORIASIS AND ATOPIC DERMATITIS: EVIDENCE FOR DIFFERENTIAL EXPRESSION OF SURFACE MOLECULES

Peripheral blood monocytes seem to be of importance for the initiation and maintenance of the psoriatic tissue reaction. Hyperproliferation of monocytopoiesis as well as functional abnormalities of monocytes in psotiasis have previously been described. We sought to determine whether peripheral blood monocyte subpopulations from patients with psoriasis show altered phentypes. and how the altered

TLR8： the forgotten relative revindicated

The endosomal Toll-like receptors （TLRs） TLR3, TLR7, TLR8 and TLR9 are important in sensing foreign nucleic acids encountered by phagocytes. Because TLR8 was initially thought to be non-functional in mice, less is known about TLR8 than the genetically and functionally related TLR7. Originally associated with the recognition of single-stranded RNA of viral origin, there is now evidence that human TLR8 is also able to sense bacterial RNA released within phagosomal vacuoles, inducing the production of both nuclear factor （NF）-κB-dependent cytokines and type I interferons （IFNs）, such as IFN-β. The functions of TLR8 extend beyond the recognition of foreign pathogens and include cross-talk with other endosomal TLRs, a process that may also have a role in the generation of autoimmunity.