MIP1 alpha nuclear protein (MNP), a novel transcription factor expressed in hematopoietic cells that is crucial for transcription of the human MIP-1 alpha gene

Macrophage Inflammatory Protein-1 Alpha (MIP-1 alpha)/CCL3: As a Biomarker

Macrophage inflammatory protein-1 alpha (MIP-1α/CCL3) is a chemotactic chemokine secreted by macrophages. It performs various biological functions, such as recruiting inflammatory cells, wound healing, inhibition of stem cells, and maintaining effector immune response. It activates bone resorption cells and directly induces bone destruction. Cells that secrete MIP-1α/CCL3 are increased at sites of inflammation and bone resorption. MIP-1α/CCL3 plays an important role in the pathogenesis of various inflammatory diseases and conditions that exhibit bone resorption, such as periodontitis, multiple myeloma, Sjögren syndrome, and rheumatoid arthritis. Biological fluids from patients with these diseases exhibit elevated levels of MIP-1α/CCL3. This finding indicates that MIP-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \alpha $$\end{document}α/CCL3 protein may have diagnostic potential for the detection of several inflammatory diseases and conditions. This chapter discusses the biological functions of MIP-1α/CCL3; describes several diseases associated with MIP-1α/CCL3, particularly periodontitis; and delineates the potential application of MIP-1α/CCL3 as a biomarker.

Magnolol suppresses NF-kappaB activation and NF-kappaB regulated gene expression through inhibition of IkappaB kinase activation

The mis-regulation of nuclear factor-kappa B (NF-kappaB) signal pathway is involved in a variety of inflammatory diseases that leds to the production of inflammatory mediators. Our studies using human U937 promonocytes cells suggested that magnolol, a low molecular weight lignan isolated from the medicinal plant Magnolia officinalis, differentially down-regulated the pharmacologically induced expression of NF-kappaB-regulated inflammatory gene products MMP-9, IL-8, MCP-1, MIP-1alpha, TNF-alpha. Pre-treatment of magnolol blocked TNF-alpha-induced NF-kappaB activation in different cell types as evidenced by EMSA. Magnolol did not directly affect the binding of p65/p50 heterodimer to DNA. Immunoblot analysis demonstrated that magnolol inhibited the TNF-alpha-stimulated phosphorylation and degradation of the cytosolic NF-kappaB inhibitor IkappaBalpha and the effects were dose-dependent. Mechanistically, a non-radioactive IkappaB kinases (IKK) assay using immunoprecipitated IKKs protein demonstrated that magnolol inhibited both intrinsic and TNF-alpha-stimulated IKK activity, thus suggesting a critical role of magnolol in abrogating the phosphorylation and degradation of IkappaBalpha. The involvement of IKK was further verified in a HeLa cell NF-kappaB-dependent luciferase reporter system. In this system magnolol suppressed luciferase expression stimulated by TNF-alpha and by the transient transfection and expression of NIK (NF-kappaB-inducing kinase), wild type IKKbeta, constitutively active IKKalpha and IKKbeta, or the p65 subunit. Magnolol was also found to inhibit the nuclear translocation and phosphorylation of p65 subunit of NF-kappaB. In line with the observation that NF-kappaB activation may up-regulate anti-apoptotic genes, it was shown in U937 cells that magnolol enhanced TNF-alpha-induced apoptotic cell death. Our results suggest that magnolol or its derivatives may have potential anti-inflammatory actions through IKK inactivation.

Lung-restricted macrophage activation in the pearl mouse model of Hermansky-Pudlak syndrome

Pulmonary inflammation, abnormalities in alveolar type II cell and macrophage morphology, and pulmonary fibrosis are features of Hermansky-Pudlak Syndrome (HPS). We used the naturally occurring "pearl" HPS2 mouse model to investigate the mechanisms of lung inflammation observed in HPS. Although baseline bronchoalveolar lavage (BAL) cell counts and differentials were similar in pearl and strain-matched wild-type (WT) mice, elevated levels of proinflammatory (MIP1gamma) and counterregulatory (IL-12p40, soluble TNFr1/2) factors, but not TNF-alpha, were detected in BAL from pearl mice. After intranasal LPS challenge, BAL levels of TNF-alpha, MIP1alpha, KC, and MCP-1 were 2- to 3-fold greater in pearl than WT mice. At baseline, cultured pearl alveolar macrophages (AMs) had markedly increased production of inflammatory cytokines. Furthermore, pearl AMs had exaggerated TNF-alpha responses to TLR4, TLR2, and TLR3 ligands, as well as increased IFN-gamma/LPS-induced NO production. After 24 h in culture, pearl AM LPS responses reverted to WT levels, and pearl AMs were appropriately refractory to continuous LPS exposure. In contrast, cultured pearl peritoneal macrophages and peripheral blood monocytes did not produce TNF-alpha at baseline and had LPS responses which were no different from WT controls. Exposure of WT AMs to heat- and protease-labile components of pearl BAL, but not WT BAL, resulted in robust TNF-alpha secretion. Similar abnormalities were identified in AMs and BAL from another HPS model, pale ear HPS1 mice. We conclude that the lungs of HPS mice exhibit hyperresponsiveness to LPS and constitutive and organ-specific macrophage activation.

A novel signaling pathway mediates the inhibition of CCL3/4 expression by prostaglandin E2

In response to pathogen-associated molecular patterns, dendritic cells initiate an innate immune response characterized by expression and release of proinflammatory cytokines and chemokines. The extent of the inflammatory response is limited by various endogenous factors, including lipid mediators such as prostaglandin E(2) (PGE(2)). We described previously the inhibitory effect of PGE(2) on the expression and release of the inflammatory chemokines CCL3 and CCL4 from activated dendritic cells. In this study we describe a novel PGE(2) signaling pathway that proceeds through EP-2 --> cAMP --> EPAC --> phosphatidylinositol 3-kinase --> protein kinase B --> GSK-3 and results in increased DNA binding of the CCAAT displacement protein (CDP), a potent mammalian transcriptional repressor. The direct link between CDP and CCL3/4 transcription was established in knock-down experiments using CDP small interference RNA.

Inhibition of macrophage inflammatory protein-1 alpha production by Epstein-Barr virus

Infection with Epstein-Barr virus (EBV) exerts substantially immunomodulating activities in vitro and in vivo. In this context, EBV-induced chemokine production and the influence of EBV on this highly redundant system of inflammatory proteins have hardly been investigated. This study analyzed the production of interleukin-8, RANTES, monocyte chemotactic protein-1, and macrophage inflammatory protein-1 alpha (MIP-1 alpha) on EBV infection of peripheral blood mononuclear cells from immune EBV-seropositive (EBV(+)) and noninfected EBV-seronegative (EBV(-)) individuals. EBV failed to induce the production of MIP-1 alpha in EBV(+) as well as EBV(-) individuals, whereas the other chemokines studied were readily expressed. Moreover, EBV completely down-regulated lipopolysaccharide (LPS)- and phytohemagglutinin-induced MIP-1 alpha production up to 4 hours after induction. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of EBV- and LPS-stimulated cultures revealed that EBV inhibited MIP-1 alpha production on the transcriptional level. This effect was abolished by addition of antiglycoprotein (gp)350/220, a monoclonal antibody against EBV's major envelope glycoprotein, which mediates binding of the virus to the EBV receptor, CD21. However, recombinant gp350/220 protein alone did not inhibit the LPS-induced MIP-1 alpha production, indicating that infection of the target cell is indispensable for this effect. In summary, we demonstrate a new immunomodulating activity of EBV on the chemokine system that probably helps the virus to evade the host's immune system favoring lifelong infection.

Novel polymorphisms in human macrophage inflammatory protein-1 alpha (MIP-1alpha) gene

Human macrophage inflammatory protein-1 alpha (MIP-1alpha) is a chemotactic cytokine, which binds to macrophages, T cells, and B cells affecting their activation. We found novel polymorphisms at four sites within MIP-1alpha gene in Japanese population: C to T in exon 2; A to G in intron 2; C to G and A to G in exon 3. They occurred on the same allele. Although MIP-1alpha effectively suppresses the replication of HIV-1 in vitro, we observed no statistically significant difference in the allele frequency of this polymorphism between HIV-1-infected and uninfected individuals in Japanese population. Since an increased transcription level of MIP-1alpha has been reported to be associated with inflammatory diseases such as atopic dermatitis, we also investigated the frequency of these polymorphisms among patients with atopic dermatitis, HIV-1-infected individuals (with a normal IgE level), and healthy donors. A small increase in ratio of homozygotes to other genotypes was observed in patients with atopic dermatitis (P = 0.04).

Impact of alcohol on the ability of Kupffer cells to produce chemokines and its role in alcoholic liver disease

Chemokines are implicated in the pathogenesis of alcoholic liver disease in humans and in experimental models of alcohol intoxication. The major sources of these chemokines are Kupffer cells which represent more than 80% of tissue macrophages in the body. Kupffer cells are highly responsive to the effects of ethanol, endotoxin and human immunodeficiency virus (HIV)-1 glycoprotein120. These agents, either independently or in combination, may exacerbate the production of chemokines. Chemokines are agents that are highly chemotactic to mononuclear cells and granulocytes. The levels of these chemokines in sera and tissue are elevated in patients with alcoholic hepatitis, alcoholic cirrhosis, diseased livers, viral hepatitis, and in experimental models of chronic alcohol intoxication. Alcohol-induced influx of endotoxin from the gut into the portal circulation is suggested to play an important role in the activation of Kupffer cells which leads to enhanced chemokine release. The up-regulation of chemokines during alcohol consumption is selective. During the early phase of alcoholic liver disease, C-X-C or alpha-chemokines predominate. This is also associated with neutrophilic infiltration of the liver. In the later stage, up-regulation of C-C or beta-chemokine production and migration of mononuclear cells into the liver are observed, and this may lead to liver cirrhosis. Selective up-regulation of chemokine synthesis and release may involve differential modulation of the transcription factors required for chemokine gene expression. Increased cytokine release following alcohol consumption may also regulate chemokine secretion in Kupffer cells via paracrine and autocrine mechanisms and vice versa. In addition, infection with HIV-1 may further compromise the liver to more damage. During HIV-1 infection, a pre-existing liver disease superimposed on chronic alcohol consumption may also exacerbate HIV-1 replication and lymphocytic infiltration in the liver, because of the ability of HIV-1 gp120 to stimulate chemokine production by Kupffer cells and stimulate migration of inflammatory leucocytes in the liver.

Human T-cell lymphotrophic virus type-I tax gene induces secretion of human macrophage inflammatory protein-1alpha

Human T-cell lymphotropic virus I (HTLV-I) encodes for a 40-kDa protein, Tax, which is important for the immortalization of T cells. Tax has been shown to transactivate several cellular genes. In this study, we show that MIP-1alpha is selectively expressed and secreted in the tax transfected Jurkat cell line upon mitogen stimulation. Expression of MIP-1alpha-R mRNA in these cells suggests an autocrine role for this chemokine in HTLV-I infected T-cells. Induced MIP-1alpha expression and secretion in PMA/PHA stimulated tax transfected cells correlate with the noninduction of MNP-1 transcription factor, which is intimately involved in downmodulating the MIP-1alpha gene.

Negative Feedback Between Prostaglandin and α- and β-Chemokine Synthesis in Human Microglial Cells and Astrocytes

The understanding of immune surveillance and inflammation regulation in cerebral tissue is essential in the therapy of neuroimmunological disorders. We demonstrate here that primary human glial cells were able to produce α- and β-chemokines (IL-8 > growth related protein α (GROα) ≫ RANTES > microphage inflammatory protein (MIP)-1α and MIP-1β) in parallel to PGs (PGE2 and PGF2α) after proinflammatory cytokine stimulation: TNF-α + IL-1β induced all except RANTES, which was induced by TNF-α + IFN-γ. Purified cultures of astrocytes and microglia were also induced by the same combination of cytokines, to produce all these mediators except MIP-1α and MIP-1β, which were produced predominantly by astrocytes. The inhibition of PG production by indomethacin led to a 37–60% increase in RANTES, MIP-1α, and MIP-1β but not in GROα and IL-8 secretion. In contrast, inhibition of IL-8 and GRO activities using neutralizing Abs resulted in a specific 6-fold increase in PGE2 but not in PGF2α production by stimulated microglial cells and astrocytes, whereas Abs to β-chemokines had no effect. Thus, the production of PGs in human glial cells down-regulates their β-chemokine secretion, whereas α-chemokine production in these cells controls PG secretion level. These data suggest that under inflammatory conditions, the intraparenchymal production of PGs could control chemotactic gradient of β-chemokines for an appropriate effector cell recruitment or activation. Conversely, the elevated intracerebral α-chemokine levels could reduce PG secretion, preventing the exacerbation of inflammation and neurotoxicity.

Distinctive calcineurin-dependent (FK506-sensitive) mechanisms regulate the production of the CC chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES vs IL-2 and TNF-alpha by activated human T cells

Calcineurin (CaN) controls the production of multiple cytokines, including IL-2 and TNF-alpha, during T cell activation. However, its role in chemokine production is unclear. Here, we used the CaN inhibitor FK506 to probe for the contribution of CaN in MIP-1alpha, MIP-1beta, and RANTES production at the protein and mRNA levels in human T cells stimulated via CD3/PMA or CD3/CD28. With both modes of activation, FK506 inhibited RANTES production only partially and late during a 3-day culture, whereas it suppressed both MIP-1alpha and MIP-1beta production throughout the culture. However, FK506 inhibition was more pronounced on MIP-1beta than MIP-1alpha, especially in CD3/CD28-activated T cells. Surprisingly, FK506 also significantly reduced MIP-1beta induction by PMA alone. Furthermore, comparison with IL-2 and TNF-alpha revealed that both were more potently inhibited by the drug upon CD3/PMA or CD3/CD28 induction than either MIP-1alpha or MIP-1beta. These differences in FK506 sensitivity were also observed in CD4(+) and CD8(+) T cell subsets. Therefore, all three chemokines are affected by FK506 distinctly from one another and from IL-2 and TNF-alpha, suggesting that CaN participates to different extents in the induction of these cytokines during T cell activation. Further evidence that this induction relies on distinctive mechanisms, depending on the cytokine, came from analyses of the kinetics and cycloheximide sensitivity of cytokine mRNA expression.

Biochemical characterization of MIP-1 alpha nuclear protein

A family of hematopoietic specific transcription factors, MIP-1 alpha nuclear protein (MNP) family, has recently been identified. They are intimately involved in regulating the transcription of the huMIP-1 alpha gene in monocytes, T-cells, and transformed B-cells. One member of the family (MNP-1) is essential for promoter activity in monocytes and B-cells, while another (MNP-2) is required for full promotor activity in T-cells. A third member of the family (MNP-3) is expressed in PMA induced HL60 cells and probably has a role in monocyte differentiation. In this communication we demonstrate by two techniques that MNP-1 and MNP-2 are distinct but related factors, and we present further evidence to show that MNP-1 acts as a heterodimer.

C-C chemokines, pivotal in protection against HIV type 1 infection

Exposure to HIV type 1 (HIV-1) does not usually lead to infection. Although this could be because of insufficient virus titer, there is now abundant evidence that some individuals resist infection even when directly exposed to a high titer of HIV. This protection recently has been correlated with homozygous mutations of an HIV-1 coreceptor, namely CCR5, the receptor for the beta-chemokines. Moreover, earlier results already had shown that the same chemokines markedly suppress the nonsyncitial inducing variants of HIV-1, the chief virus type transmitted from person to person. CCR5 mutation, as a unique mechanism of protection, is, however, suspect because HIV-1 variants can use other chemokine receptors as their coreceptor. Moreover, recent results have established that infection can indeed sometimes occur with such mutations. Here, we report on transient natural resistance over time of most of 128 hemophiliacs who were inoculated repeatedly with HIV-1-contaminated Factor VIII concentrate from plasma during 1980-1985 before the development of the HIV blood test. Furthermore, and remarkably, 14 subjects remain uninfected to this date, and in these subjects we found homozygous CCR5 mutations in none but in most of them overproduction of beta chemokines. In vitro experiments confirmed the potent anti-HIV suppressive effect of these chemokines.

The normal copy of the G0S19-3-associated, CpG island-containing, upstream sequence is downstream of G0S19-2/MIP1alpha in association with a TRE17 oncogene

The G0S19-1/MIP1alpha and G0S19-2/MIP1alpha genes locate to human chromosomes 17q and encode similar copies of the beta-chemokine G0S19/MIP1alpha. The G0S19-3 gene, present in 1 in 4 humans, is a 5' truncated version of G0S19-2; a CpG island-containing upstream sequence (CpG-US), rich in potential transcriptional activation motifs, replaces much of the first intron and the first exon. Sequences hybridizing with the CpG-US sequence, normally exist in all human genomes. Thus, it appears that there has been recombination between a duplicated G0S19 gene and a duplicated CpG-US-like sequence. We have isolated sequences hybridizing with the CpG-US sequence from a human genomic library in bacteriophage lambda. Restriction mapping and sequencing shows a CpG-US-like sequence approximately 8 kb downstream of G0S19-2 (hence, named CpG-DS sequence). The sequence is contiguous with a TRE17 oncogene-associated sequence (GenBank locus HSTRE175). Members of the TRE17 family are known to locate to chromosome 17q (Onno et al., 1993b), and have sequence characteristics suggestive of positive Darwinian selection. Linkage with a TRE17 oncogene may have arisen by recombination and imply no functional relationship. However, it is possible that the CpG-DS may normally regulate TRE17 expression. PCR and sequencing studies indicate the close proximity of other chemokine-related sequences in the 17q11.2 region.

Modulation of macrophage inflammatory protein-1alpha and its receptors in human B-cell lines derived from patients with acquired immunodeficiency syndrome and Burkitt's lymphoma

Macrophage inflammatory protein-1 alpha (MIP-1alpha) is a member of the -C-C- family of low-molecular weight chemokines. MIP-1alpha is involved in the homeostatic control of stem cell proliferation, in inducing chemotaxis, and also in inflammatory responses in mature cell types. In order to observe modulations of MIP-1alpha secretion and expression along with MIP-1alpha receptor (MIP-1alpha-R) expression for a possible autocrine role in AIDS associated B-cell lines, we studied a wide panel of human B-cell lines. Previous work by us has shown that HIV-1 tat down modulates MIP-1alpha by inducing a novel transcription factor MNP. Our data in this report suggest that HIV down modulates MIP-1alpha as a mechanism to evade suppression by this chemokine in human B-cells. Furthermore, our results strongly suggest MIP-1alpha autocrine loops in a majority of tumor B-cells as evident by MIP-1alpha-R expression, and also secretion of MIP-1alpha.

Purification and characterization of UEF3, a novel factor involved in the regulation of the urokinase and other AP-1 controlled promoters

Basal as well as induced transcription from the human urokinase-type plasminogen activator gene requires an enhancer containing two elements, a combined PEA3/AP-1 and a consensus AP-1 site. The integrity of each of these binding sites as well as their cooperation is required for activating transcription. The two elements are separated by a 74-base pair cooperation mediating (COM) region required for the cooperation between the transactivating sites. The COM region contains binding sites for four different unidentified urokinase-type plasminogen activator enhancer factors (UEF 1 to 4), all four required for correct COM activity. We have purified UEF3 from HeLa nuclear extracts by several chromatographic steps including DNA affinity purification. Purification and UV cross-linking data showed that UEF3 is a complex of three polypeptides (p40, p50, and p64). Amino acid sequence from one peptide of p64 was obtained, which showed no homology to other known proteins. Both crude and purified UEF3 specifically bound to the sequence TGACAG as shown by electrophoretic mobility shifts and methylation interference studies. DNA-binding specificity of purified UEF3 was identical to that of NIP, a non-characterized factor binding and regulating multiple AP-1-regulated promoters like stromelysin and interleukin-3. Thus UEF3 appears to be a general DNA-binding factor involved in modulating the transcriptional response of AP-1 containing promoters.