Suppression of proinflammatory cytokines in monocytes by a tetravalent guanylhydrazone

An overproduction of proinflammatory cytokines by activated macrophages/monocytes mediates the injurious sequelae of inflammation, septic shock, tissue injury, and cachexia. We recently synthesized a tetravalent guanylhydrazone compound (CNI-1493) that inhibits cytokine-inducible arginine transport and nitric oxide (NO) production in macrophages, and protects mice against lethal endotoxemia and carrageenan-induced inflammation. During these investigations we noticed that CNI-1493 effectively prevented lipopolysaccharide (LPS)-induced NO production, even when added in concentrations 10-fold less than required to competitively inhibit L-arginine uptake, suggesting that the suppressive effects of this guanylhydrazone compound might extend to other LPS-induced responses. Here, we report that CNI-1493 suppressed the LPS-stimulated production of proinflammatory cytokines (tumor necrosis factor [TNF], interleukins 1beta and 6, macrophage inflammatory proteins 1alpha and 1beta) from human peripheral blood mononuclear cells. Cytokine suppression was specific, in that CNI-1493 did not inhibit either the constitutive synthesis of transforming growth factor beta or the upregulation of major histocompatibility complex class II by interferon gamma (IFN-gamma). In contrast to the macrophage suppressive actions of dexamethasone, which are overridden in the presence of IFN-gamma, CNI-1493 retained its suppressive effects even in the presence of IFN-gamma. The mechanism of cytokine-suppressive action by CNI-1493 was independent of extracellular L-arginine content and NO production and is not restricted to induction by LPS. As a selective inhibitor of macrophage activation that prevents TNF production, this tetravalent guanylhydrazone could be useful in the development of cytokine-suppressive agents for the treatment of diseases mediated by overproduction of cytokines.

Human immunodeficiency virus type 1 infection alters chemokine beta peptide expression in human monocytes: implications for recruitment of leukocytes into brain and lymph nodes

Two chemokine (chemoattractant cytokines) beta peptides, macrophage inflammatory proteins 1 alpha and 1 beta (MIP-1 alpha and MIP-1 beta), were induced in human monocyte cultures following infection with the human immunodeficiency virus type 1 (HIV-1). Induction depended on productive viral infection: not only did the kinetics of MIP-1 peptide induction closely follow those of viral replication, but monocyte cultures inoculated with heat-inactivated virus or infected in the presence of AZT failed to produce these chemokine beta peptides. In addition, HIV infection markedly altered the pattern of beta chemokine expression elicited by tumor necrosis factor (TNF), itself a potent proinflammatory cytokine upregulated during the development of AIDS. Reverse transcription (RT)-PCR and RT-in situ PCR studies on brain tissue from patients with AIDS dementia demonstrated elevated MIP-1 alpha and MIP-1 beta mRNA expression relative to comparable samples from HIV-1-infected patients without dementia. Cells expressing chemokines in HIV-1-infected brains were identified morphologically as microglia and astrocytes. As MIP-1 alpha and MIP-1 beta are potent chemoattractants for both monocytes and specific subpopulations of lymphocytes, this dysregulation of beta chemokine expression may influence the trafficking of leukocytes during HIV infection. These data, taken together, suggest a mechanism by which HIV-1-infected monocytes might recruit uninfected T cells and monocytes to sites of active viral replication or inflammation, notably the brain and lymph nodes.

Transferrin secretion by lens epithelial cells in culture

Transferrin (Tf), the plasma iron transport protein which supports cell proliferation and differentiation and has bacteriostatic, antioxidant and anti-inflammatory activity, has been found in relatively high concentrations in the intraocular fluids. Intraocular synthesis of Tf has recently been demonstrated, although the intraocular tissue(s) responsible have not been identified. We designed this study to determine whether certain ocular tissues can make and secrete transferrin. Transferrin content of aqueous and vitreous humors and whole lenses was determined by ELISA. Transferrin secretion by cultured epithelia from lens and ciliary body was also measured. In addition, Northern blots of RNA from cultured lens epithelial cells, ciliary body pigmented and non-pigmented epithelial cells, and from whole iris, ciliary body and retina were probed with riboprobes for Tf mRNA and 18S rRNA. Transferrin made up 23% and 16% of total canine aqueous and vitreous protein. All ocular tissues and cultured cells tested contained mRNA for Tf, however Tf was secreted into the bathing medium from lens epithelial cell cultures, but not from either the pigmented or non-pigmented epithelial cells of the ciliary body cultures, but not from either the pigmented or non-pigmented epithelial cells of the ciliary body Cycloheximide inhibited secretion of Tf from the lens epithelial cells. Lenses from inflamed eyes contained higher levels of Tf than their contralateral controls. This is the first experimental demonstration that an intraocular tissue can make and secrete Tf. Transferrin secretion by the lens may contribute significantly to the IOF content of this important intraocular protein.

An inhibitor of macrophage arginine transport and nitric oxide production (CNI-1493) prevents acute inflammation and endotoxin lethality

BACKGROUND

Nitric oxide (NO), a small effector molecule produced enzymatically from L-arginine by nitric oxide synthase (NOS), is a mediator not only of important homeostatic mechanisms (e.g., blood vessel tone and tissue perfusion), but also of key aspects of local and systemic inflammatory responses. Previous efforts to develop inhibitors of NOS to protect against NO-mediated tissue damage in endotoxin shock have been unsuccessful, largely because such competitive NOS antagonists interfere with critical vasoregulatory NO production in blood vessels and decrease survival in endotoxemic animals. Accordingly, we sought to develop a pharmaceutical approach to selectively inhibit NO production in macrophages while sparing NO responses in blood vessels.

MATERIALS AND METHODS

The process of cytokine-inducible L-arginine transport and NO production were studied in the murine macrophage-like cell line (RAW 264.7). A series of multivalent guanylhydrazones were synthesized to inhibit cytokine-inducible L-arginine transport. One such compound (CNI-1493) was studied further in animal models of endothelial-derived relaxing factor (EDRF) activity, carrageenan inflammation, and lethal lipopolysaccharide (LPS) challenge.

RESULTS

Upon activation with cytokines, macrophages increase transport of L-arginine to support the production of NO by NOS. Since endothelial cells do not require this additional arginine transport to produce NO, we reasoned that a competitive inhibitor of cytokine-inducible L-arginine transport would not inhibit EDRF activity in blood vessels, and thus might be effectively employed against endotoxic shock. CNI-1493, a tetravalent guanylhydrazone, proved to be a selective inhibitor of cytokine-inducible arginine transport and NO production, but did not inhibit EDRF activity. In mice, CNI-1493 prevented the development of carrageenan-induced footpad inflammation, and conferred protection against lethal LPS challenge.

CONCLUSIONS

A selective inhibitor of cytokine-inducible L-arginine transport that does not inhibit vascular EDRF responses is effective against endotoxin lethality and significantly reduces inflammatory responses.

Multiple viral core proteins are determinants of reovirus-induced acute myocarditis

Previously, we showed that the M1 gene (encoding a viral core protein, mu 2, whose function is unknown) was associated with the efficiently myocarditic phenotype of a reovirus variant, 8B. Here, we have extended our genetic analysis of 8B and conducted genetic analyses of two other reovirus strains (T1L [serotype 1 strain Lang] and Abney). Our results demonstrate that multiple viral core proteins are determinants of reovirus-induced myocarditis. In contrast to our previous association of mu 2 with induction of myocarditis, this provides strong evidence that a core function achieved through the interaction of multiple core proteins is responsible for induction of the disease.

Risk factors for dropping out of a parenting education program

This study compared those who completed a clinic-based parenting program to dropouts in an attempt to identify risk factors for parents not completing the program. The program, aimed at mothers at risk for child maltreatment, was offered at three Seattle, Washington health centers providing comprehensive pediatric care to low-income families. We obtained baseline information from an intake questionnaire, the Nursing Child Assessment Teaching Scale (NCATS), and the Home Observation for Measurement of the Environment (HOME). Of the 172 enrollees, 124 (72%) completed the program. Univariate analyses showed that dropouts were more likely to be located at Clinic Site Three (42% vs. 10%, p < .001), teenaged (44% vs. 23%, p = .010), and African-American (56% vs. 32%, p = .010), and to have HOME scores less than 32 (57% vs. 33%, p = .023). There were no statistically significant differences between those who dropped out and those who didn't in marital status, education, referral rate to Child Protective Services prior to the start of parenting classes, or NCATS scores. Multivariate analyses showed that age less than 20 was significantly associated with dropping out when race and HOME scores were taken into account. There was significant interaction between age less than 20 and Clinic Site Three. These data suggest that program planners need to develop appropriate strategies to retain teenage mothers in parenting programs.

Differential expression of the small inducible cytokines GRO alpha and GRO beta by synovial fibroblasts in chronic arthritis: possible role in growth regulation

Synovial pannus represents a hypertrophic and locally invasive connective tissue response to chronic inflammation that accounts in large part for the periarticular destruction of rheumatoid arthritis. Synovial fibroblasts cultured from rheumatoid synovia have been found to display an increased rate of proliferation and the constitutive expression of collagenases, growth factors, and inflammatory cytokines. The existence in rheumatoid synovium of both a pro-inflammatory state and growth dysregulation led us to investigate the expression by synovial fibroblasts of the closely homologous cytokines GRO alpha (gro/MGSA), GRO beta (MIP-2 alpha), and GRO gamma (MIP-2 beta). These cytokines are released by a variety of cell types and display overlapping growth regulatory and pro-inflammatory activities. In contrast to expectations, the majority of synovial fibroblast cell lines derived from osteoarthritic or non-inflammatory synovia showed a relative increase in the constitutive expression of GRO alpha and GRO beta when compared to synovial fibroblasts obtained from rheumatoid synovia. Considered together with evidence that GRO alpha is a growth regulator that modulates the expression of metalloproteinase activity, these findings provide evidence for a differential pathway of cytokine activation that may downregulate the proliferative and erosive response to chronic arthritis.

Cytopathogenic effect in cardiac myocytes but not in cardiac fibroblasts is correlated with reovirus-induced acute myocarditis

A panel of reovirus strains was used to compare myocarditic potential with induction of cytopathic effect in primary cardiac myocyte and cardiac fibroblast cultures. The results suggest that viral cytopathogenicity in cardiac myocytes, but not in cardiac fibroblasts, is a determinant of reoviral myocarditis.

Lymphocytes protect against and are not required for reovirus-induced myocarditis

Many studies suggest that host lymphocytes are damaging, rather than protective, in virally induced myocarditis. We have investigated the role of lymphocyte-based immunity in murine myocarditis by using a myocarditic reovirus (reovirus serotype 3 8B), nonmyocarditic reoviruses, adoptive transfer experiments, and mice with severe combined immunodeficiency (SCID mice). Prior to infection, passive transfer of monoclonal antibodies specific for 8B capsid proteins protected neonatal mice against 8B-induced myocarditis, indicating that humoral immunity can protect against myocarditis. Some monoclonal antibodies acted by blocking viral spread to and/or replication in the heart. Passive transfer of reovirus-immune, but not naive, spleen cells prior to infection protected neonatal mice from 8B-induced myocarditis. Depletion of either CD4 or CD8 T cells resulted in increased viral titer in the heart but did not abrogate immune cell-mediated protection against myocardial injury. This shows that both CD4 and CD8 T cells can act independently to protect myocardial tissue from reovirus infection. In addition, reovirus 8B caused extensive myocarditis in SCID mice. This confirms a prior report (B. Sherry, F. J. Schoen, E. Wenske, and B. N. Fields, J. Virol. 63:4840-4849, 1989) that T cells are not required for reovirus-induced myocarditis and demonstrates for the first time that B cells are not required for reovirus-induced myocarditis. We used SCID mice and a panel of reoviruses to assess (i) the relationship between growth in the heart and myocardial damage and (ii) the possibility that nonmyocarditic reoviruses exhibit a myocarditic phenotype in the absence of functional lymphocytes. Growth in the heart was not the sole determinant of myocarditic potential in SCID mice. Although 8B induced myocarditis in SCID mice, no or minimal myocarditis was found in SCID mice infected with four reovirus strains previously shown (B. Sherry and B. N. Fields, J. Virol. 63:4850-4856, 1989) to be nonmyocarditic or poorly myocarditic in normal neonatal mice. We conclude that (i) humoral immunity and cellular immunity are protective against, and not required for, reovirus-induced myocarditis and (ii) the potential to induce cardiac damage is a property of the virus independent of lymphocyte-based immunity.

Fever and feeding: differential actions of macrophage inflammatory protein-1 (MIP-1), MIP-1 alpha and MIP-1 beta on rat hypothalamus

Changes in body temperature (Tb) and feeding were characterized in unrestrained rats following the micro-injection into the anterior hypothalamic preoptic area (AH/POA) of macrophage inflammatory protein-1 (MIP-1), MIP-1 alpha or MIP-1 beta. After the rats recovered from the stereotaxic implantation of a single guide tube placed in the AH/POA, either one of the MIP-1 compounds or control CSF was micro-injected in a volume of 1.0 microliter into this area. Changes in body temperature (Tb) and food and water intakes were monitored throughout each experiment. When micro-injected into the AH/POA in a dose of 28 or 280 pg, doublet MIP-1 and MIP-1 beta evoked a monophasic fever which increased above baseline to a mean maximum of 2.17 +/- 0.14 degrees C and 2.1 +/- 0.24 degrees C, respectively. MIP-1 alpha micro-injected similarly evoked a biphasic fever, with the Tb declining transiently at the 30 min point > or = 0.4 degrees C lower than the congruent rises in Tb evoked by doublet MIP-1 or MIP-1 beta. The secondary rise in Tb induced by MIP-1 alpha had a latency of 1.5-2.0 hrs and reached a maximum of 1.56 +/- 0.16 degrees C. Although all three cytokines significantly attenuated the rats' mean intake of food during the 24 hr interval after their micro-injection into the AH/POA, doublet MIP-1 exerted the most potent anorexic effect in comparison to that of the saline control rats. However, neither body weight nor intake of water was altered significantly by the three cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)

Genomic cloning and promoter analysis of macrophage inflammatory protein (MIP)-2, MIP-1 alpha, and MIP-1 beta, members of the chemokine superfamily of proinflammatory cytokines

Macrophage inflammatory protein (MIP)-2, MIP-1 alpha, and MIP-1 beta all belong to the newly recognized "chemokine" superfamily of structurally related, activation-inducible cytokines with inflammatory and growth regulatory activities. We report the isolation and sequencing of genomic clones for murine MIP-2 and murine MIP-1 beta, and analyze their regulatory sequences in comparison with each other and with several other members of the chemokine family. The murine (mu)MIP-2 genomic clone displays the canonical four exon/three intron structure typical of other genes in the chemokine alpha subfamily (e.g., IL-8). Potential cis regulatory elements in the proximal promoter region were highly conserved between muMIP-2 and its three most closely related human homologs: human (hu)GRO-alpha, huGRO-beta, and huGRO-gamma. A mouse macrophage cell line, RAW 264.7, was transfected with a growth hormone reporter construct driven by a proximal fragment of the muMIP-2 5' promoter, and nested deletion mutant analysis localized the LPS responsive element to a region that contains a conserved NF kappa B consensus motif and lies 51 to 70 bp 5' from the transcription start site. In contrast to that of MIP-2, the muMIP-1 beta genomic clone exhibited the three exon/two intron structure characteristic of the chemokine beta family members (e.g., MCP-1). A comparison of the promoters for muMIP-1 beta and muMIP-1 alpha reveals a conserved CK-1 element, but transient expression studies in RAW 264.7 macrophages with proximal fragments of either the muMIP-1 beta or the muMIP-1 alpha 5' promoter fused to a human growth hormone reporter gene link LPS-inducibility in both to promoter segments near to, but not identical with, the consensus CK-1 sequence. Proximal 5' promoter fragments cloned from both the MIP-1 alpha and MIP-1 beta genes unexpectedly conferred constitutive expression on the fused reporter gene sequences in macrophage-like cells, but initial 5' deletion analysis did not link this responsiveness to known sequence motifs. The muMIP-1 beta promoter, but not the muMIP-1 alpha promoter, was constitutively active in B16 mouse melanoma cells, and both promoters were active in the myelomonocytic cell line WEHI 3B(A)d-, the muMIP-1 alpha promoter being three times stronger.

Genomic cloning and promoter analysis of macrophage inflammatory protein (MIP)-2, MIP-1 alpha, and MIP-1 beta, members of the chemokine superfamily of proinflammatory cytokines

Macrophage inflammatory protein (MIP)-2, MIP-1 alpha, and MIP-1 beta all belong to the newly recognized "chemokine" superfamily of structurally related, activation-inducible cytokines with inflammatory and growth regulatory activities. We report the isolation and sequencing of genomic clones for murine MIP-2 and murine MIP-1 beta, and analyze their regulatory sequences in comparison with each other and with several other members of the chemokine family. The murine (mu)MIP-2 genomic clone displays the canonical four exon/three intron structure typical of other genes in the chemokine alpha subfamily (e.g., IL-8). Potential cis regulatory elements in the proximal promoter region were highly conserved between muMIP-2 and its three most closely related human homologs: human (hu)GRO-alpha, huGRO-beta, and huGRO-gamma. A mouse macrophage cell line, RAW 264.7, was transfected with a growth hormone reporter construct driven by a proximal fragment of the muMIP-2 5' promoter, and nested deletion mutant analysis localized the LPS responsive element to a region that contains a conserved NF kappa B consensus motif and lies 51 to 70 bp 5' from the transcription start site. In contrast to that of MIP-2, the muMIP-1 beta genomic clone exhibited the three exon/two intron structure characteristic of the chemokine beta family members (e.g., MCP-1). A comparison of the promoters for muMIP-1 beta and muMIP-1 alpha reveals a conserved CK-1 element, but transient expression studies in RAW 264.7 macrophages with proximal fragments of either the muMIP-1 beta or the muMIP-1 alpha 5' promoter fused to a human growth hormone reporter gene link LPS-inducibility in both to promoter segments near to, but not identical with, the consensus CK-1 sequence. Proximal 5' promoter fragments cloned from both the MIP-1 alpha and MIP-1 beta genes unexpectedly conferred constitutive expression on the fused reporter gene sequences in macrophage-like cells, but initial 5' deletion analysis did not link this responsiveness to known sequence motifs. The muMIP-1 beta promoter, but not the muMIP-1 alpha promoter, was constitutively active in B16 mouse melanoma cells, and both promoters were active in the myelomonocytic cell line WEHI 3B(A)d-, the muMIP-1 alpha promoter being three times stronger.

Comparative analysis of the human macrophage inflammatory protein family of cytokines (chemokines) on proliferation of human myeloid progenitor cells. Interacting effects involving suppression, synergistic suppression, and blocking of suppression

Macrophage inflammatory protein (MIP)-1 alpha, part of a family termed chemokines, has been implicated in suppression of hemopoietic stem and progenitor cell proliferation. The chemokine family has been organized into two subgroups with MIP-1 alpha, MIP-1 beta, macrophage chemotactic and activating factor (MCAF) and RANTES belonging to one subgroup, and GRO-alpha, MIP-2 alpha (GRO-beta), MIP-2 beta (GRO-gamma), platelet factor 4 (PF4), IL-8, and neutrophil activating peptide (NAP)-2 belonging to the other. These molecules were evaluated for effects on colony formation by human bone marrow multipotential (CFU-GEMM), erythroid (BFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells. None of the chemokines stimulated colony formation in the absence of CSF, or influenced colony formation stimulated by a single growth factor such as granulocyte-macrophage-CSF or erythropoietin. However, MIP-1 alpha, MIP-2 alpha, PF4, IL-8, and MCAF suppressed in dose-response fashion colony formation of immature subsets of myeloid progenitor cells stimulated by GM-CSF plus steel factor. Effects were apparent on low density and CD34 HLA-DR(+)-sorted marrow cells in which up to 88.4% of the cells were composed of progenitor cells, suggesting direct effects on the progenitors themselves. Up to 2500-fold less of each chemokine could be used to demonstrate synergistic suppression when any two of these five chemokines were used together at low concentrations, effects also apparently directly on the progenitors. In contrast, MIP-1 beta, MIP-2 beta, GRO-alpha, NAP-2, and RANTES were not suppressive nor did they synergize with MIP-1 alpha, MIP-2 alpha, PF4, IL-8, or MCAF to suppress. However, a fivefold excess of MIP-1 beta blocked the suppressive effects of MIP-1 alpha. Similarly, a fivefold excess of either MIP-2 beta or GRO-alpha blocked the suppressive effects of IL-8 and PF4. These suppressing, synergizing and blocking effects may be of relevance to blood cell regulation.

Comparative analysis of the human macrophage inflammatory protein family of cytokines (chemokines) on proliferation of human myeloid progenitor cells. Interacting effects involving suppression, synergistic suppression, and blocking of suppression

Macrophage inflammatory protein (MIP)-1 alpha, part of a family termed chemokines, has been implicated in suppression of hemopoietic stem and progenitor cell proliferation. The chemokine family has been organized into two subgroups with MIP-1 alpha, MIP-1 beta, macrophage chemotactic and activating factor (MCAF) and RANTES belonging to one subgroup, and GRO-alpha, MIP-2 alpha (GRO-beta), MIP-2 beta (GRO-gamma), platelet factor 4 (PF4), IL-8, and neutrophil activating peptide (NAP)-2 belonging to the other. These molecules were evaluated for effects on colony formation by human bone marrow multipotential (CFU-GEMM), erythroid (BFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells. None of the chemokines stimulated colony formation in the absence of CSF, or influenced colony formation stimulated by a single growth factor such as granulocyte-macrophage-CSF or erythropoietin. However, MIP-1 alpha, MIP-2 alpha, PF4, IL-8, and MCAF suppressed in dose-response fashion colony formation of immature subsets of myeloid progenitor cells stimulated by GM-CSF plus steel factor. Effects were apparent on low density and CD34 HLA-DR(+)-sorted marrow cells in which up to 88.4% of the cells were composed of progenitor cells, suggesting direct effects on the progenitors themselves. Up to 2500-fold less of each chemokine could be used to demonstrate synergistic suppression when any two of these five chemokines were used together at low concentrations, effects also apparently directly on the progenitors. In contrast, MIP-1 beta, MIP-2 beta, GRO-alpha, NAP-2, and RANTES were not suppressive nor did they synergize with MIP-1 alpha, MIP-2 alpha, PF4, IL-8, or MCAF to suppress. However, a fivefold excess of MIP-1 beta blocked the suppressive effects of MIP-1 alpha. Similarly, a fivefold excess of either MIP-2 beta or GRO-alpha blocked the suppressive effects of IL-8 and PF4. These suppressing, synergizing and blocking effects may be of relevance to blood cell regulation.

Human recombinant macrophage inflammatory protein-1 alpha and -beta and monocyte chemotactic and activating factor utilize common and unique receptors on human monocytes

The human macrophage inflammatory proteins-1 alpha and -beta (MIP-1 alpha and -beta), which are also known as LD78 and ACT2, respectively, are distinct but highly related members of the chemoattractant cytokine (chemokine) family. rMIP-1 alpha and -beta labeled with 125I specifically bind to human peripheral blood monocytes, the monocytic cell line THP-1, peripheral blood T cells, and the YT cell line. Steady state binding experiments revealed approximately 3000 high affinity binding sites/cell for MIP-1 alpha on human monocytes and on THP-1 cells, with Kd values of 383 pM and 450 pM, respectively. Human MIP-1 alpha and -beta had nearly identical affinities for the binding sites and each competed equally well for binding. Human monocyte chemotactic and activating factor (MCAF), a member of the same chemokine family, consistently displaced about 25% of human MIP-1 alpha and -beta binding on monocytes but not on YT cells, which did not bind MCAF. On the other hand, human rMIP-1 alpha and -beta partially inhibited binding of radiolabeled MCAF to monocytes. Both MIP-1 alpha and -beta were chemotactic for human monocytes. Preincubation of monocytes with human rMIP-1 alpha or -beta markedly reduced cell migration towards the other cytokine, whereas preincubation with human rMCAF only partially desensitized the monocyte chemotaxis response to human rMIP-1 alpha or -beta. These data suggest the existence of three subtypes of receptors, i.e., one unique receptor shared by MIP-1 alpha and -beta, a second unique receptor for MCAF, and a third species that recognizes both MCAF and MIP-1 peptides.

Human recombinant macrophage inflammatory protein-1 alpha and -beta and monocyte chemotactic and activating factor utilize common and unique receptors on human monocytes

The human macrophage inflammatory proteins-1 alpha and -beta (MIP-1 alpha and -beta), which are also known as LD78 and ACT2, respectively, are distinct but highly related members of the chemoattractant cytokine (chemokine) family. rMIP-1 alpha and -beta labeled with 125I specifically bind to human peripheral blood monocytes, the monocytic cell line THP-1, peripheral blood T cells, and the YT cell line. Steady state binding experiments revealed approximately 3000 high affinity binding sites/cell for MIP-1 alpha on human monocytes and on THP-1 cells, with Kd values of 383 pM and 450 pM, respectively. Human MIP-1 alpha and -beta had nearly identical affinities for the binding sites and each competed equally well for binding. Human monocyte chemotactic and activating factor (MCAF), a member of the same chemokine family, consistently displaced about 25% of human MIP-1 alpha and -beta binding on monocytes but not on YT cells, which did not bind MCAF. On the other hand, human rMIP-1 alpha and -beta partially inhibited binding of radiolabeled MCAF to monocytes. Both MIP-1 alpha and -beta were chemotactic for human monocytes. Preincubation of monocytes with human rMIP-1 alpha or -beta markedly reduced cell migration towards the other cytokine, whereas preincubation with human rMCAF only partially desensitized the monocyte chemotaxis response to human rMIP-1 alpha or -beta. These data suggest the existence of three subtypes of receptors, i.e., one unique receptor shared by MIP-1 alpha and -beta, a second unique receptor for MCAF, and a third species that recognizes both MCAF and MIP-1 peptides.

Short, thin, or obese? Comparing growth indexes of children from high- and low-poverty areas

This study compared the growth indexes of first-grade, white children living in geographic areas of high poverty (n = 281) and low poverty (n = 442) in the state of Washington. Obesity was the most common growth deviance observed in these children. In the low-poverty area, 18% of children had a weight for height greater than the 90th percentile on the National Center for Health Statistics (NCHS) growth standards, whereas only 12% of children from the high-poverty area were in this category. Neither area had high numbers of children with reduced weight for height (less than the 10th percentile on the NCHS growth standards), but children from the high-poverty area were almost twice as likely to be short for their age; 9% of children from the high-poverty area and 5% of children from the low-poverty area had height-for-age values less than the 10th percentile on the NCHS growth standards. Criteria used to determine students' eligibility for financial support for school lunch did not accurately identify children who were thin or short. The prevalence of obesity in these first-grade children suggests that school-based growth screening as well as weight management and physical fitness programs are needed to identify and avert childhood obesity.

Myelosuppressive effects in vivo of purified recombinant murine macrophage inflammatory protein-1 alpha

Purified recombinant murine macrophage inflammatory protein-1 alpha (rmuMIP-1 alpha), a cytokine with myelopoietic activity in vitro, was assessed in vivo by injection into C3H/HeJ mice for effects on proliferation (percentage of cells in S phase DNA synthesis of the cell cycle) and absolute numbers of granulocyte-macrophage, erythroid, and multipotential progenitor cells in the femur and spleen, and on nucleated cellularity in the bone marrow, spleen, and blood. rmuMIP-1 alpha rapidly decreased cycling rates (at 2 to 10 micrograms/mouse i.v.) and absolute numbers (at 5 to 10 micrograms/mouse i.v.) of myeloid progenitor cells in the marrow and spleen. These effects were dose- and time-dependent and reversible. Suppressive effects were noted within 3 to 24 h for cell cycling and absolute numbers of progenitor cells in the marrow and spleen, and by 48 h for circulating neutrophils. A study comparing the effects of i.v. injection of rmuMIP-1 alpha versus rmuMIP-1 beta, a biochemically similar molecule but with no myelosuppressive effects in vitro, demonstrated myelosuppression in vivo by rmuMIP-1 alpha, but not by rmuMIP-1 beta. The results suggest that rmuMIP-1 alpha has myelosuppressive activity in vivo and offers the possibility that it may be a useful adjunct to treatments involving cytotoxic drugs because of its reversible suppressive effects on normal progenitor cell cycling.

Myelosuppressive effects in vivo of purified recombinant murine macrophage inflammatory protein-1 alpha

Purified recombinant murine macrophage inflammatory protein-1 alpha (rmuMIP-1 alpha), a cytokine with myelopoietic activity in vitro, was assessed in vivo by injection into C3H/HeJ mice for effects on proliferation (percentage of cells in S phase DNA synthesis of the cell cycle) and absolute numbers of granulocyte-macrophage, erythroid, and multipotential progenitor cells in the femur and spleen, and on nucleated cellularity in the bone marrow, spleen, and blood. rmuMIP-1 alpha rapidly decreased cycling rates (at 2 to 10 micrograms/mouse i.v.) and absolute numbers (at 5 to 10 micrograms/mouse i.v.) of myeloid progenitor cells in the marrow and spleen. These effects were dose- and time-dependent and reversible. Suppressive effects were noted within 3 to 24 h for cell cycling and absolute numbers of progenitor cells in the marrow and spleen, and by 48 h for circulating neutrophils. A study comparing the effects of i.v. injection of rmuMIP-1 alpha versus rmuMIP-1 beta, a biochemically similar molecule but with no myelosuppressive effects in vitro, demonstrated myelosuppression in vivo by rmuMIP-1 alpha, but not by rmuMIP-1 beta. The results suggest that rmuMIP-1 alpha has myelosuppressive activity in vivo and offers the possibility that it may be a useful adjunct to treatments involving cytotoxic drugs because of its reversible suppressive effects on normal progenitor cell cycling.

Macrophage inflammatory protein 1 modulates macrophage function

Macrophage inflammatory protein 1 (MIP 1), initially purified from the conditioned medium of endotoxin-stimulated macrophages, is a low m.w. heparin-binding protein doublet comprising two peptides, MIP 1 alpha and MIP 1 beta. Although native doublet MIP 1 has previously been shown to exert pyrogenic, mitogenic, and proinflammatory effects on other cell types, its actions on its cell of origin, the macrophage, have not been well catalogued. Our study reports several aspects of macrophage function that are modulated by MIP 1. MIP 1 was not directly cytotoxic for WEHI tumor cells, but MIP 1-treated macrophage exhibited enhanced antibody-independent macrophage cytotoxicity for tumor targets. MIP 1 treatment stimulated proliferation of mature tissue macrophages, and this effect was enhanced upon costimulations with either CSF-1 or granulocyte-macrophage-CSF. Thioglycollate-elicited peritoneal exudate macrophages incubated with native doublet MIP 1-secreted bioactive TNF and IL-6, as well as immunoreactive IL-1 alpha, and these effects were enhanced significantly when the cells were costimulated with IFN-gamma. Purified preparations of the recombinantly derived MIP 1 alpha peptide alone stimulated the secretion of TNF, IL-1 alpha, and IL-6 by peritoneal macrophages, but MIP 1 beta did not. In fact, as little as eightfold excess MIP 1 beta blocked TNF-induction by MIP 1 alpha to a significant degree. By contrast to these apparent "macrophage activating" properties of MIP 1, the cytokine failed to trigger the macrophage oxidative burst, or to up-regulate the expression of Ia on the macrophage surface. Taken together, these data reveal that MIP 1 peptides act as autocrine modulators of their cells of origin, and raise the possibility that MIP 1 peptides may play a role in modulating macrophage responses to inflammatory stimuli in vivo.

Macrophage inflammatory protein 1 modulates macrophage function

Macrophage inflammatory protein 1 (MIP 1), initially purified from the conditioned medium of endotoxin-stimulated macrophages, is a low m.w. heparin-binding protein doublet comprising two peptides, MIP 1 alpha and MIP 1 beta. Although native doublet MIP 1 has previously been shown to exert pyrogenic, mitogenic, and proinflammatory effects on other cell types, its actions on its cell of origin, the macrophage, have not been well catalogued. Our study reports several aspects of macrophage function that are modulated by MIP 1. MIP 1 was not directly cytotoxic for WEHI tumor cells, but MIP 1-treated macrophage exhibited enhanced antibody-independent macrophage cytotoxicity for tumor targets. MIP 1 treatment stimulated proliferation of mature tissue macrophages, and this effect was enhanced upon costimulations with either CSF-1 or granulocyte-macrophage-CSF. Thioglycollate-elicited peritoneal exudate macrophages incubated with native doublet MIP 1-secreted bioactive TNF and IL-6, as well as immunoreactive IL-1 alpha, and these effects were enhanced significantly when the cells were costimulated with IFN-gamma. Purified preparations of the recombinantly derived MIP 1 alpha peptide alone stimulated the secretion of TNF, IL-1 alpha, and IL-6 by peritoneal macrophages, but MIP 1 beta did not. In fact, as little as eightfold excess MIP 1 beta blocked TNF-induction by MIP 1 alpha to a significant degree. By contrast to these apparent "macrophage activating" properties of MIP 1, the cytokine failed to trigger the macrophage oxidative burst, or to up-regulate the expression of Ia on the macrophage surface. Taken together, these data reveal that MIP 1 peptides act as autocrine modulators of their cells of origin, and raise the possibility that MIP 1 peptides may play a role in modulating macrophage responses to inflammatory stimuli in vivo.

Identification of cyclophilin as a proinflammatory secretory product of lipopolysaccharide-activated macrophages

We have isolated an 18-kDa peptide (designated sp18, for 18-kDa secreted protein) from the conditioned medium of lipopolysaccharide-stimulated RAW 264.7 murine macrophages. Purified sp18 had in vivo inflammatory activity and in vitro chemotactic activity for human peripheral blood polymorphonuclear leukocytes and monocytes. Surprisingly, N-terminal sequencing and tryptic mapping studies revealed that sp18 and cyclophilin, an intracellular protein that binds the immunosuppressive drug cyclosporin A, are highly homologous. The in vitro chemotactic activity of sp18 on monocytes was blocked by cyclosporin A but not by cyclosporin H, a structural analog of cyclosporin A that does not bind cyclophilin. Like purified porcine cyclophilin, mouse sp18 exhibited peptidyl-prolyl cis-trans isomerase activity. Medium conditioned by lipopolysaccharide-stimulated resident peritoneal exudate macrophages isolated from C57BL/6 mice contained substantially higher levels of sp18/cyclophilin than medium conditioned by nonstimulated macrophages. The observation that sp18/cyclophilin exhibits proinflammatory activity and is secreted by macrophages in response to endotoxin suggests that this protein may function as a cytokine, and invites the hypothesis that the immunosuppressive action of cyclosporin A results in part from interaction with an extracellular form of cyclophilin released as a mediator of immune and inflammatory functions.

A longitudinal study of the relationship between vitamin A supplementation and plasma retinol, retinyl esters, and liver enzyme activities in a healthy elderly population

This study examined the association between dietary supplementation with vitamin A and biochemical symptoms of toxicity in 116 healthy elderly volunteers (47 male, 69 female), aged 64-88 y. Plasma retinol and retinyl ester concentrations, seven liver-function tests, and dietary and supplemental vitamin A intakes were measured annually for 5 y. Supplemental intake range was 0-47,000 IU/d; dietary intake range was 2528-23,032 IU/d. Fasting retinol and retinyl ester concentrations were determined by HPLC and dietary intake was assessed by a 3-d food record. Supplemental vitamin A intake was highly correlated with retinyl ester concentrations (r = 0.74, P = 0.0001). Retinyl esters ranges from 3.4% to 10.2% of retinol concentrations. Retinyl ester concentrations did not increase over time, regardless of supplement amount. The association of retinyl esters and liver-function tests was significant only for aspartate aminotransferase activity in females (r = 0.47, P = 0.0001). The supplementation amount in this study was not associated with vitamin A toxicity.