Macrophage inflammatory protein-1

Macrophage inflammatory protein-1 (MIP-1) and MIP-1β are highly related members of the CC chemokine subfamily. Despite their structural similarities, MIP-1 and MIP-1β show diverging signaling capacities. Depending on the MIP-1 subtype and its NH₂-terminal processing, one or more of the CC chemokine receptors CCR1, CCR2, CCR3 and CCR5 are recognized. Since both human MIP-1 subtypes (LD78 and LD78β) and MIP-1β signal through CCR5, the major co-receptor for M-tropic HIV-1 strains, these chemokines are capable of inhibiting HIV-1 infection in susceptible cells. In this review, different aspects of human and mouse MIP-1 and MIP-1β are discussed, including their protein and gene structures, their regulated production, their receptor usage and biological activities and their role in several pathologies including HIV-1 infection.     

Macrophage inflammatory protein-1

Macrophage inflammatory protein (MIP)-1alpha was identified 15 years ago as the first of now four members of the MIP-1 CC chemokine subfamily. These proteins termed CCL3 (MIP-1alpha), CCL4 (MIP-1beta), CCL9/10 (MIP-1delta), and CCL15 (MIP-1gamma) according to the revised nomenclature for chemokines are produced by many cells, particularly macrophages, dendritic cells, and lymphocytes. MIP-1 proteins, which act via G-protein-coupled cell surface receptors (CCR1, 3, 5), e.g. expressed by lymphocytes and monocytes/macrophages (MPhi), are best known for their chemotactic and proinflammatory effects but can also promote homoeostasis. The encouraging results of preclinical studies in murine models of inflammation, i.e. asthma, arthritis, or multiple sclerosis, have led to the development of potent CCR3 and 5 antagonists, some of which are currently being tested in first clinical trials.     

Macrophage procoagulant activity as a measure of cell-mediated immunity in the mouse

Thioglycollate-induced peritoneal exudate cells (TG-PEC) developed increased procoagulant activity after incubation with lymphokine and lipopolysaccharide (LPS). Dilutions of up to 1/1000 for insoluble Con A and 1/200 for periodate-induced lymphokine supernatants were active in enhancing macrophage procoagulant activity (MPCA), which was detected after a 2-hr incubation period and steadily increased over 20 hr. MPCA could also be induced by antigen; peritoneal cells from sensitized B6AF1 mice with strong footpad reactions to ovalbumin (OVA) responded to as little as 0.1 microgram/ml OVA in the MPCA test in an antigen-specific manner. By contrast, PEC from sensitized CBA/J mice that gave poor in vivo responses to OVA only reacted with high concentrations of the antigen in vitro. Production of the lymphokine responsible for induction of MPCA required an Ly-1+2- T cell, a nylon wool-adherent cell, and an la-17-bearing adherent cell. The MPCA induced by lymphokine or LPS did not appear to be a serine esterase and was not inhibited by phospholipase C. Coagulation of human factor-deficient plasma with activated TG-PEC indicated a requirement for Factor X.     

Wistar大鼠的自发肿瘤病变及其发生率

目的了解Wistar大鼠的各种自发性肿瘤病变及其发生率。方法致癌实验中的对照组,采用4周龄SPF级Wistar大鼠,雌、雄性大鼠各60只,实验前观察1周,常规饲料喂饲104周后处死,进行组织病理学检查。结果报告了Wistar大鼠的各种自发性肿瘤病变及其发生率。雄性大鼠中发生肿瘤的动物占49.12%,发生良性肿瘤的动物占38.60%、发生恶性肿瘤的动物占17.54%;良性肿瘤主要有垂体腺瘤(19.30%)、睾丸间质细胞瘤(5.26%)和皮下纤维瘤(5.26%);恶性肿瘤主要有鳞状细胞癌(7.02%)和淋巴造血系统肿瘤(3.51%)。雌性大鼠中发生肿瘤的动物占60.34%;发生良性肿瘤的动物占50.00%、发生恶性肿瘤的动物占15.52%;良性肿瘤主要有乳腺纤维腺瘤(25.86%)和垂体腺瘤(24.14%);恶性肿瘤主要有腺癌(5.17%)和乳腺癌(3.45%)。结论本文报告的Wistar大鼠自发肿瘤及其发生率进一步丰富了现有SPF级Wistar大鼠自发性肿瘤的数据资料,可为有关技术人员提供一定的参考和借鉴。     

Gene expression profile of mouse white adipose tissue during inflammatory stress: age‐dependent upregulation of major procoagulant factors

Tolerance to physiological stress resulting from inflammatory disease decreases significantly with age. High mortality rates, increased cytokine production, and pronounced thrombosis are characteristic complications of aged mice with acute systemic inflammation induced by injection with lipopolysaccharide (LPS). As adipose tissue is now recognized as an important source of cytokines, we determined the effects of aging on visceral white adipose tissue gene expression during LPS‐induced inflammation in male C57BL/6 mice. Microarray analysis revealed that the expression of 6025 genes was significantly changed by LPS; of those, the expression of 667 showed an age‐associated difference. Age‐associated differences were found in many genes belonging to the inflammatory response and blood clotting pathways. Genes for several procoagulant factors were upregulated by LPS; among these, tissue factor, thrombospondin‐1, and plasminogen activator inhibitors‐1 and ‐2, exhibited age‐associated increases in expression which could potentially contribute to augmented thrombosis. Further analysis by qRT–PCR, histological examination, and cell fraction separation revealed that most inflammatory and coagulant‐related gene expression changes occur in resident stromal cells rather than adipocytes or infiltrating cells. In addition, basal expression levels of 303 genes were altered by aging, including increased expression of component of Sp100‐rs (Csprs). This study indicates that adipose tissue is a major organ expressing genes for multiple inflammatory and coagulant factors and that the expression of many of these is significantly altered by aging during acute inflammation. Data presented here provide a framework for future studies aimed at elucidating the impact of adipose tissue on age‐associated complications during sepsis and systemic inflammation.     

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.     

Exosomes and immune surveillance of neoplastic lesions: a review

The immune system has been reported to suppress the development and progression of neoplastic lesions; however, the exact mechanisms by which neoplastic lesions and the immune system interact are not well understood. Within the last decade, tiny membrane bound particles, approximately 30-100 nm in diameter, have been observed in the blood and other body fluids. These particles, currently called exosomes, are released from many types of tissues including tumors, and they contain and carry many proteins, and mRNAs and microRNA species. We review here how tumors suppress the immune system, especially by the formation of exosomes. Exosomes released from tumors are carried in part by the vascular system to distant cells, which phagocytose them. Depending on the proteins, mRNAs or microRNAs in the exosomes and the cell type, phagocytosis of exosomes may provide a modulating signal to the cell. In the case of exosomes from tumors, uptake of the exosomes by cells of the immune system has been reported to have three main effects: 1) suppression of the number and activity of natural killer cells, 2) suppression of the activity of T cells and 3) suppression of the number and maturation of mature dendritic cells.     

Differential effects of somatostatin on circulating tissue factor procoagulant activity and protein

The tissue factor (TF) pathway is the primary mechanism for initiation of blood coagulation. Circulating blood contains TF, which originates mainly from monocytes and is thrombogenic. The presence of somatostatin (SMS) receptors on monocytes suggests the possibility that SMS may regulate TF synthesis and/or release. Circulating TF procoagulant activity (TF-PCA), factor VIIa activity (FVIIa; clotting assays), TF antigen (TF-Ag; ELISA), prothrombin fragment 1.2 (F1.2), thrombin-antithrombin complexes (ELISAs), CD40 ligand expression on platelets, and monocyte-platelet aggregates (flow cytometry) were determined in blood from normal volunteers undergoing 24 h of basal glucose/basal insulin (BG/BI) clamps and high-glucose/high-insulin (HG/HI) clamps with and without SMS. Infusions of SMS under basal conditions (BG/BI) raised TF-PCA 1.8-fold (P < 0.03), TF-Ag 2.3-fold (P < 0.001), and TF expression on monocytes by 36% (P < 0.001) and decreased plasma levels of FVIIa by 30% (P < 0.001). Infusion of SMS reduced the 8.6-fold HG/HI-induced increase in TF-Ag by 26% and the 8.6-fold increase in TF-PCA by 100%. SMS also prevented the 60% increase in TF expression on monocytes, the 2.2-fold increase in F1.2, the 40% increase in CD40L expression on platelets, and the 17% increase in monocyte-platelet aggregates seen during HG/HI. We conclude that SMS completely prevented HG/HI-induced TF activation in normal volunteers and may be of use to reduce the procoagulant state and acute vascular events in hyperinsulinemic insulin-resistant patients with type 2 diabetes.     

Spontaneous neoplastic lesions in aged Sprague-Dawley rats.

Neoplastic lesions were observed in untreated aged Sprague Dawley (SD) rats throughout their lifespan starting at 5 weeks. Their mean survival times were 89 to 105 weeks of age. The total tumor incidences were 70 to 76.7% and 87 to 95.8% in males and females, respectively. The common neoplasmas were pituitary adenoma and adrenal pheochromocytoma in both sexes, testicular Leydig cell tumor in males and mammary gland tumors, thyroidal C-cell adenoma and uterine stromal polyp in females.     

A simplified and high-throughput chromogenic assay for testing tissue factor-dependent procoagulant activity

Tissue factor (TF), the primary initiator of the coagulation cascade, plays a critical role in hemostasis and thrombosis, and inhibition of TF activity appears to be an attractive target for the treatment of cardiovascular diseases. However, few selective small-molecule inhibitors of TF are available, and the present assays for measuring TF activity are relatively expensive and complex. The authors present a simple and high-throughput chromogenic assay for screening TF inhibitors based on using commercial human prothrombin complex instead of purified coagulation factors, reducing the dosage, and performing with a one-stage procedure. In the optimized assay, <45 μL cell lysates was incubated with Tris-CaCl(2) buffer (pH 7.3) containing human prothrombin complex at 37°C for 15 min in 96-well or 384-well plates. Tris-EDTA buffer (pH 8.4) containing chromogenic substrate Xa was then added and the absorbance measured at 405 nm. This simplified assay was more sensitive or precise than some reported methods for TF procoagulant activities. Two known active compounds (curcumin and simvastatin) inhibiting TF activity were tested by the simplified assay to validate the screening method. Furthermore, berberine and cryptotanshinone suppressed TF activity induced by lipopolysaccharides in human monocytes by this assay and might be promising new TF inhibitors.     

Nicotinamide methylation tissue distribution,developmental and neoplastic changes

The distribution of cytosolic activity of nicotinamide:S-adenosylmethionine methyltransferase (nicotinamide methylase, EC 2.1.1.1) in normal tissues from adult rat and mouse and in tumors and the change in the enzyme activity during the the development of rat tissues were studied. (1) Rat liver exhibited the highest nicotinamide methylase activity among all adult tissues tested; other rat tissues, like adrenal, pancreas, kidney, brain and mouse tissues, had only less than 15% of the adult rat liver activity. (2) 3 days before birth, fetal liver showed a very low nicotinamide methylase activity (2% of adult rat liver), which, however, increased already 1 day before birth and reached the adult level on the day 28 after birth. (3) In a variety of hepatomas and ascites tumors, an inverse correlation, with some exceptions, between tumor growth rate and nicotinamide methylase activity could be seen. In all hepatomas, with the exception of Morris hepatoma 5123tc, nicotinamide methylase activity was significantly decreased in comparison to normal adult rat liver. The highly malignant Zajdela hepatoma, Yoshida sarcoma, sarcoma 180 and Ehrlich ascites tumor methylated nicotinamide only at a negligibly low rate. (4) Cultured RLC cells (an established rat liver cell line) from the stationary growth phase or G₁-arrested RLC cells had about half of the adult rat liver activity, yet the activity was 70% higher than that of the logarithmically growing RLC cells.     

The pro-migratory and pro-invasive role of the procoagulant tissue factor in malignant gliomas

During the infiltration process, glioma cells are known to migrate along preexisting anatomical structures such as blood vessels, axonal fiber tracts and the subependymal space, thereby widely invading surrounding CNS tissue. This phenomenon represents a major obstacle for the clinical treatment of these tumors. Several extracellular key factors and intracellular signaling pathways have been previously linked to the highly aggressive, invasive phenotype observed in malignant gliomas. The glioblastoma (GBM), which is the most malignant form of these tumors, is histologically characterized by areas of tumor necroses and pseudopalisading cells, the latter likely representing tumor cells actively migrating away from the hypoxic- ischemic core of the tumor. It is believed that intravascular thromboses play a major role in the emergence of hypoxia and intratumoral necroses in GBMs. One of the most highly upregulated prothrombotic factor in malignant gliomas is tissue factor (TF), a 47 kDa type I transmembrane protein belonging to the cytokine receptor superfamily. In a recent study, we provided evidence that TF/FVIIa signaling via the protease-activated receptor 2 (PAR-2) promotes cell growth, migration and invasion of glioma cells. In this Commentary & View, we outline the key molecular players involved in migration and invasion of gliomas, highlight the potential role of TF for the pro-migratory and pro-invasive phenotype of these tumors and discuss the underlying mechanisms on the cellular level and in the tumor microenvironment.Key words: brain tumor, blood coagulation, hypoxia, MAP kinase, cancer stem cells, tumor invasion