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Monocyte Differentiation (monocyte + differentiation)

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Medical Sciences	80%

Selected Abstracts

Targeted tumor necrosis factor receptor I preligand assembly domain improves skin lesions in MRL/lpr mice

ARTHRITIS & RHEUMATISM, Issue 8 2010
Guo-Min Deng
Objective Skin disease is the second most common manifestation in patients with systemic lupus erythematosus (SLE). Tumor necrosis factor receptor (TNFR) preligand assembly domain (PLAD) has been found to block the effect of TNF,, and TNFRI PLAD (p60 PLAD) inhibits inflammatory arthritis. This study was undertaken to investigate whether TNFR PLAD limits inflammatory skin injury in a mouse model of SLE. Methods Female MRL/lpr mice received p60 PLAD (100 ,g/mouse intraperitoneally), p80 PLAD (100 ,g/mouse intraperitoneally), or phosphate buffered saline (100 ,l/mouse intraperitoneally) 3 times a week for 26 weeks, starting at age 6 weeks. Results Immunohistochemistry studies demonstrated that TNFRI but not TNFRII was dominantly expressed in skin lesions in MRL/lpr mice. We found that TNFRI PLAD (p60 PLAD) but not TNFRII PLAD (p80 PLAD) protein significantly inhibited skin injury in the MRL/lpr mouse model of lupus. NF-,B, monocyte chemotactic protein 1, and inducible nitric oxide synthase expression in skin lesions were significantly inhibited by p60 PLAD. Lupus serum,induced monocyte differentiation into dendritic cells was reduced by p60 PLAD, but p60 PLAD did not reduce IgG deposition in the skin or improve the progression of kidney damage in MRL/lpr mice. Conclusion Our results indicate that TNFRI is involved in the expression of skin injury in MRL/lpr mice with lupus and that p60 PLAD or similar biologics may be of clinical value if applied locally. [source]

Mediation of nonerosive arthritis in a mouse model of lupus by interferon-,,stimulated monocyte differentiation that is nonpermissive of osteoclastogenesis

ARTHRITIS & RHEUMATISM, Issue 4 2010
Kofi A. Mensah
Objective In contrast to rheumatoid arthritis (RA), the joint inflammation referred to as Jaccoud's arthritis that occurs in systemic lupus erythematosus (SLE) is nonerosive. Although the mechanism responsible is unknown, the antiosteoclastogenic cytokine interferon-, (IFN,), whose transcriptome is present in SLE monocytes, may be responsible. This study was undertaken to examine the effects of IFN, and lupus on osteoclasts and erosion in the (NZB × NZW)F1 mouse model of SLE with K/BxN serum,induced arthritis. Methods Systemic IFN, levels in (NZB × NZW)F1 mice were elevated by administration of AdIFN,. SLE disease was marked by anti,double-stranded DNA (anti-dsDNA) antibody titer and proteinuria, and Ifi202 and Mx1 expression represented the IFN, transcriptome. Microfocal computed tomography was used to evaluate bone erosions. Flow cytometry for CD11b and CD11c was used to evaluate the frequency of circulating osteoclast precursors (OCPs) and myeloid dendritic cells (DCs) in blood. Results Administration of AdIFN, to (NZB × NZW)F1 mice induced osteopetrosis. (NZB × NZW)F1 mice without autoimmune disease were fully susceptible to focal erosions in the setting of serum-induced arthritis. However, (NZB × NZW)F1 mice with high anti-dsDNA antibody titers and the IFN, transcriptome were protected against bone erosions. AdIFN, pretreatment of NZW mice before K/BxN serum administration also resulted in protection against bone erosion (r2 = 0.4720, P < 0.01), which was associated with a decrease in the frequency of circulating CD11b+CD11c, OCPs and a concomitant increase in the percentage of CD11b+CD11c+ cells (r2 = 0.6330, P < 0.05), which are phenotypic of myeloid DCs. Conclusion These findings suggest that IFN, in SLE shifts monocyte development toward myeloid DCs at the expense of osteoclastogenesis, thereby resulting in decreased bone erosion. [source]

Cell wall-associated alpha-glucan is instrumental for Mycobacterium tuberculosis to block CD1 molecule expression and disable the function of dendritic cell derived from infected monocyte

CELLULAR MICROBIOLOGY, Issue 8 2007
Maria Cristina Gagliardi
Summary We previously described an escape mechanism exploited by Mycobacterium tuberculosis (Mtb) to prevent the generation of fully competent dendritic cells (DC). We have now tested the effect of isolated mycobacterial components on human monocyte differentiation into DC and demonstrated that cell wall (CW)-associated alpha-glucan induces monocytes to differentiate into DC (Glu-MoDC) with the same altered phenotype and functional behaviour of DC derived from Mtb-infected monocytes (Mt-MoDC). In fact, Glu-MoDC lack CD1 molecule expression, fail to upregulate CD80 and produce IL-10 but not IL-12. We also showed that Glu-MoDC are not able to prime effector T cells or present lipid antigens to CD1-restricted T-cell clones. Thus, we propose a mechanism of Mtb,monocyte interaction mediated by CW-associated alpha-glucan, which allows the bacterium to evade both innate and acquired immune responses. [source]

,Danger' effect of low-density lipoprotein (LDL) and oxidized LDL on human immature dendritic cells

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2007
R. Zaguri
Summary Dendritic cell (DC) maturation may accelerate autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis, and may contribute to accelerated atherosclerosis seen in these patients. The immune system responds to both exogenous and endogenous ,dangerous' signals that can induce dendritic cell maturation. We have found that autologous plasma contains danger signals that induce up-regulation of major histocompatibility complex (MHC) class II and co-stimulatory molecules in immature DCs (iDCs). The objective of this study was to determine whether low-density lipoprotein (LDL) and/or oxidized LDL (oxLDL) constitute danger signals, and to assess the effect of exposure to LDL and oxLDL following monocyte differentiation into iDCs in lipoprotein-deficient serum (LPDS). IDCs were generated in the presence of autologous plasma or LPDS. Expression of maturation and migration molecules was evaluated using flow cytometry, and morphology was assessed by light microscopy. Pro- or anti-apoptotic effect was determined using annexin V and propidium iodide binding. Phagocytosis of apoptotic cells was evaluated using autologous plasma or LPDS. LDL and oxLDL were clearly able to slightly up-regulate levels of HLA-DR and co-stimulatory molecule CD86. High oxLDL concentrations (50,100 µg/ml) were associated with expression of additional maturation molecules. Moreover, iDCs that were prepared in LPDS showed partial maturation following exposure to LDL and oxLDL, and improved tolerogenic apoptotic cell uptake. This study suggests that oxLDL, and to some extent LDL, are at least partly responsible for the iDC ,danger' response induced by autologous plasma. [source]

Clonogenicity, gene expression and phenotype during neutrophil versus erythroid differentiation of cytokine-stimulated CD34+ human marrow cells in vitro

BRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2004
Louise Edvardsson
Summary With the objective to correlate clonogenicity, gene expression and phenotype during differentiation, human bone marrow CD34+ cells were cultured in vitro to stimulate erythroid or neutrophil development, and sorted into five subpopulations according to their surface expression of CD15/CD33 and blood group antigen A/CD117 respectively. Sorted cells were cultured in methylcellulose and analysed by real-time reverse transcription polymerase chain reaction for expression of neutrophil and erythroid marker genes. Surface expression of CD15 coincided with restriction to neutrophil/monocyte differentiation and A antigen with restriction to erythroid differentiation. GATA-2 mRNA was down-regulated during both neutrophil and erythroid maturation, whereas GATA-1, SCL, ABO, erythropoietin receptor, Kell, glycophorin A, , -globin and , -haemoglobin stabilizing protein were up-regulated during erythroid differentiation and silenced during neutrophil differentiation. CCAAT/enhancer-binding protein (C/EBP)- ,, PU.1, granulocyte colony-stimulating factor receptor, PR3, C/EBP- , and lactoferrin were sequentially expressed during neutrophil differentiation but rapidly down-regulated during the early erythroid stages. Nuclear factor erythroid-derived 2 (NF-E2) and glycophorin C were expressed both during neutrophil and erythroid differentiation. Our data support the notion of early expression of several lineage-associated genes prior to actual lineage commitment, defined by surface expression of CD15 and A antigen as markers for definitive neutrophil/monocyte and erythroid differentiation respectively. Previous findings, primarily from cell lines and mouse models, have been extended to adult human haematopoiesis. [source]