Comparative effects of prolyl-leucyl-glycinamide and naloxone on morphine-induced inhibition of gastrointestinal transit

The effects of prolyl-leucyl-glycinamide (MIF) and naloxone on the gastrointestinal transit in mice were investigated using the charcoal meal test. MIF administered intraperitoneally (IP) (1-10 mg/kg) or intracerebroventricularly (ICV) (10 micrograms/mouse) had no effect on the transit. Administration of morphine by subcutaneous (SC) route significantly inhibited the gastrointestinal transit. The morphine-induced inhibition of the transit was not affected by MIF whether given by IP or ICV route. Administration of the opiate antagonist naloxone (1 mg/kg, IP or 10 micrograms/mouse, ICV) had no effect on the gastrointestinal transit, but it significantly antagonized the inhibition produced by morphine. Some earlier studies have indicated narcotic antagonistic effect of MIF. However, in the present study, evidence for such an action of MIF was not obtained. It is suggested that MIF does not appear to have narcotic antagonistic activity and further supports an earlier study from this laboratory that MIF may not interact with opiate receptors.     

Binding characteristics of fluoresceinated Lotus tetragonolobus fucolectin to macrophage populations which are either responsive or refractory to activation by lymphokine

Fucose binding protein (FBP) from Lotus tetragonolobus seed was studied by fluorescence microscopy for its binding characteristics to various guinea pig peritoneal macrophage populations. Fluoresceinated FBP (FITC-FBP) was bound optimally at 22 degrees C in a punctate distribution and was internalized at 37 degrees C. Binding of FBP to macrophages was reversed specifically by the competitive sugar L-fucose, and not by D-fucose, L-rhamnose, or D-galactose. FBP was bound with greater frequency and intensity to 3-day oil-elicited peritoneal macrophages which are responsive to migration inhibition by FBP and migration inhibitory factor (MIF) than to resident or 7-day inflammatory macrophages which are unresponsive to activation by the same effectors. Competition for visual binding of FITC-FBP to macrophages was demonstrated by preincubation of cells with unlabeled FBP or MIF. Competition of FITC-FBP binding by MIF was reversed by L-fucose. These results indicate that FBP binds preferentially, with greater frequency and intensity, to macrophage subpopulations which are responsive to MIF than to MIF-refractory macrophages. The data further supports the existence of a common receptor site for MIF and FBP on the macrophage membrane which involves fucosyl determinants.     

Development of narcotic tolerance and physical dependence: effects of Pro-Leu-Gly-NH2 and cyclo (Leu-Gly)

Administration of Pro-Leu-Gly-NH2 (MIF) and cyclo (Leu-Gly) blocked the development of tolerance to and physical dependence on morphine, induced by the pellet implanation procedure in mice. Inhibition of tolerance development by peptides was evidenced by the presence of an analgesic response (increase in jump threshold) as determined by measuring the jump threshold to an increasing electric current, after a challenge dose of morphine (40 mg/kg). The same dose of morphine did not alter the jump threshold in morphine tolerant mice which were injected with saline prior to pellet implantation. The inhibition of the development of physical dependence on morphine by these peptides was evidenced by the antagonism of the hypothermic response which occurs during abrupt or naloxone-induced withdrawal. The naloxone-induced withdrawal jumping response was unaffected by these peptides. Dose-response experiments indicated that cyclo (leu-Gly) was much more potent than MIF in these tests. These peptides, when given after the development of tolerance and dependence, did not modify either the analgesic response to morphine or the symptoms of abrupt and naloxone-precipitated withdrawal. The inhibition of development of analgesic tolerance and physical dependence was not associated with changes in brain morphine concentration. The data indicate that these peptides do not interfere withe the morphine-morphine receptor complex formation but alter a subsequent step in the genesis of some aspects of tolerance and dependence processes.     

Ursolic acid promotes the release of macrophage migration inhibitory factor via ERK2 activation in resting mouse macrophages

Macrophage migration inhibitory factor (MIF) plays some pivotal roles in innate immunity and inflammation. Ursolic acid (UA), an anti-inflammatory triterpene carboxylic acid, was recently reported to induce the release of pro-inflammatory mediators in resting macrophages (Mvarphi). We investigated the effects of UA on MIF protein release in resting RAW264.7 mouse Mvarphi, and found that it decreased intracellular MIF protein levels and promoted the release of MIF into the culture media in dose- and time-dependent manners, without affecting mRNA levels. Further, the triterpene strikingly induced activation of mitogen-activated protein kinase kinase 1/2 (MEK1/2) and extracellular signal-regulated kinase 1/2 (ERK1/2) within 30min, whereas no phosphorylation of p38 MAPK or JNK protein was observed. In addition, UA-promoted MIF release was significantly inhibited by PD98059, a MEK1/2 inhibitor, while siRNA for ERK2, but not ERK1, significantly decreased the amount of MIF protein released. These results suggest that UA triggers the release of intracellular MIF protein through the ERK2 activation.     

慢性乙型肝炎患者血清MIF、IL-17及IL-10的检测及其临床意义

目的探讨巨噬细胞移动抑制因子(MIF)、白细胞介素(IL)-17及IL-10在慢性乙型肝炎(乙肝)发病中的可能作用及临床意义。方法选择48例慢性乙肝患者(HBeAg阳性与阴性各24例;HBV DNA阴性21例,HBV DNA阳性27例)作为试验组,24例健康人作为对照组,采用酶联免疫吸附试验(ELISA)测定两组血清中MIF、IL-17及IL-10的含量。结果试验组与对照组结果比较,MIF[(67.50±9.21)μg/Lvs(25.21±7.08)μg/L]和IL-17[(70.93±2.24)vs(26.78±1.58)μg/L]明显升高,IL-10[(192.88±20.74)vs(240.32±28.33)μg/L]明显下降,差异均有统计学意义(P<0.05)。HBeAg阴性与阳性组、HBV DNA阴性与阳性组中MIF、IL-17及IL-10的含量差异均无统计学意义。MIF、IL-17的含量与ALT呈正相关(r=0.693,P<0.01;r=0.897,P<0.001),而IL-10与ALT呈负相关(r=-0.285,P=0.037)。结论 MIF、IL-17及IL-10可能参与慢性乙肝的发病过程,具...     

妊娠期糖尿病MIF表达及相关影响因素分析

目的研究巨噬细胞移动抑制因子(MIF)在妊娠期糖尿病中的表达及影响因素。方法半定量RT-PCR扩增妊娠期糖尿病患者和正常孕妇腹部皮下脂肪细胞MIF基因;ELISA法检测外周血清MIF因子浓度;分析MIF与BMI、TC、TG、LDL、HLDL相关性。结果妊娠期糖尿病患者MIF mRNA表达率(0.625+0.17)和血清MIF(3.86+0.52ng/ml)均显著高于正常孕妇。结论 MIF是妊娠期糖尿病显著影响因子,MIF与BMI、TC、TG、LDL正相关,与HLDL负相关。     

巨噬细胞移动抑制因子在妊娠期糖尿病病情变化中的诊断价值

目的:探讨妊娠期糖尿病(GDM)患者体内巨噬细胞移动抑制因子(MIF)水平变化及其与血糖(Glu)水平的关系。方法:ELISA法检测GDM、2型糖尿病(T2DM)患者血清MIF;采用高效液相法检测GHbA1C,采用生化法检测Glu。结果:GDM组及T2DM组MIF水平高于正常对照组,但MIF水平在GDM患者及T2DM组无统计学差别。T2DM组MIF与Glu水平均呈正相关(r=0.826,P<0.001),GHbA1C与Glu呈正相关(r=0.471,P<0.05)。GDM组MIF与Glu水平均呈正相关(r=0.605,P<0.01),GHbA1C与Glu水平呈正相关(r=0.528,P<0.01),正常对照组内各指标间无相关性。GDM组血清MIF水平与孕龄呈正相关(r=0.938,P<0.001)。结论:GDM及糖尿病患者血糖及GHbA1C水平可致患者MIF高表达。高水平MIF可能对妊娠过程产生影响,应引起临床重视。     

A new assay for rapid measurement of MIF levels by 3H-labelled cells in liquid scintillation counting vials: Statistical implications for the measurement of migration inhibition

A new quantitative assay for migration inhibitory factor (MIF) employs ³H-labelled cultured mouse or human lymphoid cells migrating from capillary tubes. Capillaries filled with labelled cells are placed in liquid scintillation counting vials, along with the MIF- containing sample and are removed at the end of a five-hour incubation period. The residual, labelled cells which have migrated out of the tubes are solubilized and counted in a liquid scintillation counter. While cultured lymphoblast cells are routinely used in the assay, the method was checked against mouse and guinea pig peritoneal exudate cells in both the labelled cell technique and the conventional chamber assay. The assay is technically simple to perform and a useful tool for laboratory research purposes because of the short span of time needed to obtain the results. These advantages indicate a potential for automation and use of this assay in a clinical immunology laboratory. Statistical analysis of data from both assays demonstrated that the relative variation among replicates is lower in the labelled cell assay. The new assay also measured a significant difference between controls and MIF-containing samples when the migration index (MI) was greater than 80%. Criteria for significant inhibition of migration are discussed in regard to the use of analysis variance (ANOVA) and other statistical procedures, and the inadequacy of a single measure, such as the MI, is discussed.     

Role of macrophage migration inhibitory factor in head and neck cancer and novel therapeutic targets: A systematic review

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in systemic, autoimmune, and inflammatory diseases, such as obesity, rheumatoid arthritis, and systemic lupus erythematosus. For the 2 past decades, MIF has been reported to participate in carcinogenesis, disease prognosis, tumor cell proliferation, invasion, and tumor‐induced angiogenesis in many cancers. The purpose of this article is to review published experimental and clinical data for MIF and its involvement in upper aerodigestive tract cancers. Based on the current literature, we propose a biomolecular model describing the mechanisms underlying the involvement of MIF in the initiation, progression, apoptosis, and proliferation of head and neck tumor cells. In reference to this model, potential therapeutic approaches based on the use of MIF antagonists and neutralizing antibodies are described. It is concluded that MIF is a promising target for future therapeutic strategies, both with and without chemoradiation strategies.