Primary structure of rat CD14 and characteristics of rat CD14, cytokine, and NO synthase mRNA expression in mononuclear phagocyte system cells in response to LPS

Ovine CD14- an Immune Response Gene Has a Role Against Gastrointestinal Nematode Haemonchus contortus-A Novel Report

CD14 (also known as the monocyte differentiation antigen) is an important immune response gene known to be primarily responsible for innate immunity against bacterial pathogens, and as a pattern recognition receptor (PRR), binds with LPS (endotoxin), lipoproteins, and lipotechoic acid of bacteria. So far very limited work has been conducted in parasitic immunology. In the current study, we reported the role of CD14 in parasitic immunology in livestock species (sheep) for the first time. Ovine CD14 is characterized as a horse-shoe shaped bent solenoid with a hydrophobic amino-terminal pocket for CD14 along with domains. High mutation frequency was observed, out of total 41 mutations identified, 23 mutations were observed to be thermodynamically unstable and 11 mutations were deleterious in nature, causing major functional alteration of important domains of CD14, an indication of variations in individual susceptibility for sheep against Haemonchus contortus infestations. In silico studies with molecular docking reveal a role of immune response against Haemonchus contortus in sheep, which is later confirmed with experimental evidence through differential mRNA expression analysis for sheep, which revealed better expression of CD14 in Haemonchus contortus infected sheep compared to that of non-infected sheep. We confirmed the above findings with supportive evidence through haematological and biochemical analyses. Phylogenetic analysis was conducted to assess the evolutionary relationship with respect to humans and it was observed that sheep may well be used as model organisms due to better genetic closeness compared to that of mice.

Modulating effect of MgO-SiO2 nanoparticles on immunological and histopathological alterations induced by aflatoxicosis in rats

INTRODUCTION

AflatoxinB1 (AFB1) is well-known as a feed borne-hepatotoxic and immunosuppressive mycotoxin. This study was conducted to evaluate the efficacy of nanocomposite magnesium oxide and silicon oxide (MgO-SiO₂) in reducing the toxic effects of AFB1on the immunity and histological alterations in liver, spleen and intestine of adult male rats.

EXPERIMENTAL DESIGN

Animals were divided into a control (Gp1) and three experimental groups (Gps); Gp2 received feed contained 200 ppb AFB1, Gp3 received feed contained 200 ppb AFB1 and 0.5 g/kg MgO-SiO₂ nanocomposite. While, rats of Gp4 received feed contained 0.5 g/kg MgO-SiO₂ nano-composite.

METHODS

Cellular and humoral immune responses, as well as histopathological examination and caspase-3 expression in liver, spleen, and intestine, were all evaluated. Residual concentration of AFB1was determined in serum, liver and fecal samples. The obtained data were statistically analyzed.

RESULTS

AFB1markedly reduced body weight gain and food and water consumption. Cellular immune response (total and differential leukocytes count, neutrophils' phagocytic activity, lymphocyte transformation, macrophage activity and serum lysozyme activity), serum total protein, and humoral immune response (fractions of protein as estimated by SDS- PAGE electrophoresis) were all severely reduced by AFB1. Moreover, AFB1induced marked histological alterations and apoptosis in liver, spleen, and intestine.

CONCLUSION

These findings suggested that the nanocomposite MgO-SiO₂ has high affinity to adsorb AFB1 and can effectively modulate its toxicity in rats.

IMPACT STATEMENT

Nanocomposite MgO-SiO₂ may offer a novel effective and cheap approach for the preventive management of aflatoxicosis in animals.

Changes in serum cytokine levels, hepatic and intestinal morphology in aflatoxin B1-induced injury: modulatory roles of melatonin and flavonoid-rich fractions from Chromolena odorata

Aflatoxins are known to produce chronic carcinogenic, mutagenic, and teratogenic effects, as well as acute inflammatory effects, especially in the gastrointestinal tract. The potentials of the flavonoid-rich extract from Chromolena odorata (FCO) and melatonin (a standard anti-oxidant and anti-inflammatory agent) against aflatoxin B1 (AFB1)-induced alterations in pro-inflammatory cytokine levels and morphology of liver and small intestines were evaluated in this study. We utilized Wistar albino rats (200-230 g) randomly divided into five groups made up of group A, control rats; group B, rats given AFB1 (2.5 mg/kg, intraperitoneal) twice on days 5 and 7; rats in groups C, D, and E were treated with melatonin (10 mg/kg, intraperitoneal) or oral doses of FCO1 (50 mg/kg) and FCO2 (100 mg/kg) for 7 days, respectively, along with AFB1 injection on days 5 and 7. Serum levels of interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) were determined using commercial ELISA kits and histopathological evaluation of the liver, duodenum, and ileum were also carried out. We observed significant elevation (p < 0.05) in serum IL-1β correlating with hemorrhages and leucocytic and lymphocytic infiltration in the liver and intestines as evidences of an acute inflammatory response to AFB1 administration. All treatments yielded significant reduction (p < 0.05) in IL-1β levels, although TNF-α levels were not significantly altered in all rats that received AFB1, irrespective of the treatments. Melatonin and FCO2 produced considerable protection of hepatic tissues, although melatonin was not quite effective in protecting the intestinal lesions. Our findings suggest a modulation of cytokine expression that may, in part, be responsible for the abilities of C. odorata or melatonin in amelioration of hepatic and intestinal lesions associated with aflatoxin B1 injury.

CD14 upregulation as a distinct feature of non-alcoholic fatty liver disease after pancreatoduodenectomy

AIM

To investigate the pathogenesis of non-alcoholic fatty liver disease (NAFLD) after pancreatoduodenectomy (PD).

METHODS

A cohort of 82 patients who underwent PD at Okayama University Hospital between 2003 and 2009 was enrolled and the clinicopathological features were compared between patients with and without NAFLD after PD. Computed tomography (CT) images were evaluated every 6 mo after PD for follow-up. Hepatic steatosis was diagnosed on CT when hepatic attenuation values were 40 Hounsfield units. Liver biopsy was performed for 4 of 30 patients with NAFLD after PD who consented to undergo biopsies. To compare NAFLD after PD with NAFLD associated with metabolic syndrome, liver samples were obtained from 10 patients with NAFLD associated with metabolic syndrome [fatty liver, n = 5; non-alcoholic steatohepatitis (NASH), n = 5] by percutaneous ultrasonography-guided liver biopsy. Double-fluorescence immunohistochemistry was applied to examine CD14 expression as a marker of lipopolysaccharide (LPS)-sensitized macrophage cells (Kupffer cells) in liver biopsy specimens.

RESULTS

The incidence of postoperative NAFLD was 36.6% (30/82). Univariate analysis identified cancer of the pancreatic head, sex, diameter of the main pancreatic duct, and dissection of the nerve plexus as factors associated with the development of NAFLD after PD. Those patients who developed NAFLD after PD demonstrated significantly decreased levels of serum albumin, total protein, cholesterol and triglycerides compared to patients without NAFLD after PD, but no glucose intolerance or insulin resistance. Liver biopsy was performed in four patients with NAFLD after PD. All four patients showed moderate-to-severe steatosis and NASH was diagnosed in two. Numbers of cells positive for CD68 (a marker of Kupffer cells) and CD14 (a marker of LPS-sensitized Kupffer cells) were counted in all biopsy specimens. The number of CD68+ cells in specimens of NAFLD after PD was significantly increased from that in specimens of NAFLD associated with metabolic syndrome specimens, which indicated the presence of significantly more Kupffer cells in NAFLD after PD than in NAFLD associated with metabolic syndrome. Similarly, more CD14+ cells, namely, LPS-sensitized Kupffer cells, were observed in NAFLD after PD than in NAFLD associated with metabolic syndrome. Regarding NASH, more CD68+ cells and CD14+ cells were observed in NASH after PD specimens than in NASH associated with metabolic syndrome. This showed that more Kupffer cells and more LPS-sensitized Kupffer cells were present in NASH after PD than in NASH associated with metabolic syndrome. These observations suggest that after PD, Kupffer cells and LPS-sensitized Kupffer cells were significantly upregulated, not only in NASH, but also in simple fatty liver.

CONCLUSION

NAFLD after PD is characterized by both malnutrition and the up-regulation of CD14 on Kupffer cells. Gut-derived endotoxin appears central to the development of NAFLD after PD.

Molecular Characterization and SNP Detection of CD14 Gene of Crossbred Cattle

CD14 is an important molecule for innate immunity that can act against a wide range of pathogens. The present paper has characterized CD14 gene of crossbred (CB) cattle (Bos indicus×Bos taurus). Cloning and sequence analysis of CD14 cDNA revealed 1119 nucleotide long open reading frame encoding 373 amino acids protein and 20 amino acids signal peptide. CB cattle CD14 gene exhibited a high percentage of nucleotide identity (59.3–98.1%) with the corresponding mammalian homologs. Cattle and buffalo appear to have diverged from a common ancestor in phylogenetic analysis. 25 SNPs with 17 amino acid changes were newly reported and the site for mutational hot-spot was detected in CB cattle CD14 gene. Non-synonymous substitutions exceeding synonymous substitutions indicate the evolution of this protein through positive selection among domestic animals. Predicted protein structures obtained from deduced amino acid sequence indicated CB cattle CD14 molecule to be a receptor with horse shoe-shaped structure. The sites for LPS binding, LPS signalling, leucine-rich repeats, putative N-linked glycosylation, O-linked glycosylation, glycosyl phosphatidyl inositol anchor, disulphide bridges, alpha helix, beta strand, leucine rich nuclear export signal, leucine zipper and domain linker were predicted. Most of leucine and cysteine residues remain conserved across the species.

CD14: a soluble pattern recognition receptor in milk

An innate immune system capable of distinguishing among self, non-self, and danger is a prerequisite for health. Upon antigenic challenge, pattern recognition receptors (PRRs), such as the Toll-like receptor (TLR) family of proteins, enable this system to recognize and interact with a number of microbial components and endogenous host proteins. In the healthy host, such interactions culminate in tolerance to self-antigen, dietary antigen, and commensal microorganisms but in protection against pathogenic attack. This duality implies tightly regulated control mechanisms that are not expected of the inexperienced neonatal immune system. Indeed, the increased susceptibility of newborn infants to infection and to certain allergens suggests that the capacity to handle certain antigenic challenges is not inherent. The observation that breast-fed infants experience a lower incidence of infections, inflammation, and allergies than formula-fed infants suggests that exogenous factors in milk may play a regulatory role. There is increasing evidence to suggest that upon exposure to antigen, breast milk educates the neonatal immune system in the decision-making processes underlying the immune response to microbes. Breast milk contains a multitude of factors such as immunoglobulins, glycoproteins, glycolipids, and antimicrobial peptides that, qualitatively or quantitatively, may modulate how neonatal cells perceive and respond to microbial components. The specific role of several of these factors is highlighted in other chapters in this book. However, an emerging concept is that breast milk influences the neonatal immune system's perception of "danger." Here we discuss how CD14, a soluble PRR in milk, may contribute to this education.

Cloning, characterization and mapping of porcine CD14 reveals a high conservation of mammalian CD14 structure, expression and locus organization

The cell surface protein CD14 plays a central role in innate immunity as a pattern recognition receptor. CD14 is part of a receptor complex also including toll-like receptor 4 and MD2 proteins. Binding of the ligand lipopolysaccharide to the complex on myeloid cells leads to release of pro-inflammatory cytokines and mediators from the cell. In this study, we present the cloning, characterization and tissue expression pattern of a porcine CD14 encoding cDNA, and the chromosomal localization of the porcine CD14 gene. The open reading frame is predicted to encode a protein of 373 amino acids, which shows conservation of structural as well as functional regions when compared to other mammalian species. The CD14 gene was localized to porcine chromosome 2 in a region syntenic to human chromosome 5q. Transcription analysis shows that CD14 is widely expressed in tissues examined in this study, which correlates well with expression primarily on myeloid cells.

Role of Kupffer cells in host defense and liver disease

Kupffer cells (KC) constitute 80-90% of the tissue macrophages present in the body. They reside within the lumen of the liver sinusoids, and are therefore constantly exposed to gut-derived bacteria, microbial debris and bacterial endotoxins, known to activate macrophages. Upon activation KC release various products, including cytokines, prostanoides, nitric oxide and reactive oxygen species. These factors regulate the phenotype of KC themselves, and the phenotypes of neighboring cells, such as hepatocytes, stellate cells, endothelial cells and other immune cells that traffic through the liver. Therefore, KC are intimately involved in the liver's response to infection, toxins, ischemia, resection and other stresses. This review summarizes established basic concepts of KC function as well as their role in the pathogenesis of various liver diseases.

Specific messenger RNA expression for signal transduction molecules by lipopolysaccharide in intestinal macrophages

Intestinal macrophages are known to display profound inflammatory anergy in response to lipopolysacchraide (LPS). To study the mechanisms of unresponsiveness of intestinal macrophages to LPS, we compared the mRNA expression of molecules associated with signal transduction of intestinal macrophages with those of other tissue macrophages. Also cellular localization of CD14 protein was examined. Intestinal, alveolar and peritoneal macrophages were isolated from rats or mice. The expression of mRNA was assessed by real-time PCR, and cellular localization of CD14 protein was examined by flow cytometry. Cellular responses to LPS were examined by production of TNF and NO. The expression of CD14 mRNA in intestinal macrophages was lower than for peritoneal macrophages but higher than for alveolar macrophages. The mRNA expression of other molecules corresponding to intracellular signal transduction in intestinal macrophages was similar with alveolar and peritoneal macrophages. Despite the presence of CD14 mRNA, proteins of CD14 were not detected on cell surfaces of intestinal macrophages, and induction of TNF or NO responding to LPS were not detected. Flow cytometric analysis demonstrated that CD14 protein was not expressed on the cell surface but was expressed inside intestinal macrophages. The unresponsiveness of intestinal macrophages after LPS exposure is considered to be largely attributed to the lack of CD14 protein on their cell surfaces. However, CD14 protein was expressed inside of the cells, suggesting that post-transcriptional regulation rather than transcriptional suppression may play a dominant role in determining the phenotype of the intestinal macrophages.

Hepatocytes enhance effects of lipopolysaccharide on liver nonparenchymal cells through close cell interactions

The response to lipopolysaccharide (LPS) in the liver is complex, requiring cell-to-cell interactions between hepatocytes and liver nonparenchymal cells (NPC), in particular, Kupffer cells. Previous studies show that cytokines produced by Kupffer cells stimulated with LPS can, in turn, activate hepatocytes. In the present study, we sought to examine whether the reverse, hepatocyte (HC)-NPC interactions, is important in cytokine production in mixed cell cocultures. LPS-stimulated production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 from NPC was augmented in mixed HC-NPC cocultures, as compared with NPC monocultures. This HC-NPC interaction was not observed when hepatocytes were cocultured with NPC from TLR4-mutant (C3H/HeJ) mice or CD14-deficient mice. The effect was partially lost when hepatocytes from lipopolysaccharide-binding protein (LBP)-deficient mice were cocultured with wild-type mice. These data indicate that functional TLR4 and CD14 are required for NPC production of cytokines and that at least one of the critical components from hepatocytes is LBP. The augmented cytokine production by mixed HC-NPC cocultures was abrogated when the cells were separated by a filter system, indicating that close cell interactions are also required for this interaction. Thus, interaction between hepatocytes and NPC are critical for cytokine secretion by NPC.

Effects of acute moderate exercise on the phagocytosis of Kupffer cells in rats

AIM

This study investigated the function of Kupffer cells, and particularly their role as immunocompetent cells that come into contact with gut-derived endotoxin, in the acute exercise of rats.

METHODS

Female Fischer 344 rats were run on a treadmill at 21 m min(-1) for 60 min on a 15% grade.

RESULTS

Afterwards, the number of latex particles in the liver was higher in the exercising rats than that in resting rats and an increase in the number of latex particles phagocytosed by each Kupffer cell was noted. The plasma endotoxin concentration was significantly higher in the exercise group than in the resting rats, and the small intestine was damaged by the exercise. Plasma corticosterone and thyroxine 4 levels were unchanged. Although the number of Kupffer cells was unchanged by acute exercise, the number of CD14-positive Kupffer cells increased. Plasma liver enzyme activities were slightly increased by acute exercise, whereas plasma tumour necrosis factor-alpha was not detected.

CONCLUSION

These results suggest that moderately intense exercise increases the phagocytosis of Kupffer cells, and that it might be induced by endotoxemia of portal blood caused by intestinal mucosal lesions resulting from acute exercise.

Hepatic (dys-)function during inflammation

It is an understatement to say that the liver is an important organ. Each of the liver cells goes through thousands of complex biochemical interactions that influence all of the other organs in the body. Since the liver is involved with almost all biochemical processes it is no wonder that there are many different diseases that will affect it. A process known to impair liver function, including hepatic drug metabolism, is an infection induced inflammatory response. Infection induced alterations in liver function involve various cell types and their continuous cross-talk, as well as several circulating or locally secreted inflammatory mediators. Three main hepatic cell types contribute to the liver response during inflammation: hepatocytes, Kupffer cells and sinusoidal endothelial cells. In addition, activated neutrophils, which are also recruited in the liver and produce potentially destructive enzymes and oxygen-derived radicals, may further enhance liver injury. This review will focus on the pathway by which Kupffer cells and hepatocytes are activated and how this affects liver function, in particular hepatic drug metabolism.

Roles of CD14 in LPS-induced liver injury and lethality in mice pretreated with Propionibacterium acnes

The mechanism of the liver damage and lethality in Propionibacterium acnes (P. acnes)-LPS system remains obscure. To examine the role of CD14 in the system, M14M mice, in which CD14 was expressed heterotopically under the control of the metallothionein promoter were used. The production of soluble CD14 (sCD14) was increased by both P. acnes - priming and LPS challenge (1 microg per mouse) in both nontransgenic and M14M mice, although the plasma level was much higher in M14M nontransgenic than mice. The size of granulomas induced by an intraperitoneal administration of P. acnes in M14M mice 7 days after priming was smaller than that in nontransgenic mice. An LPS challenge induced apoptotic and necrotic changes in hepatocytes in nontransgenic mice but not in M14M mice. The challenge dose resulted in almost 90% lethality in nontransgenic mice but not in M14M mice 24h after challenge. TNF-alpha, IFN-gamma, IL-12, IL-18 and inducible nitric oxide synthase (iNOS) mRNA expressions produced by LPS challenge in M14M mice were low compared with those in nontransgenic mice. IL-18 mRNA expression was upregulated in P. acnes-primed nontransgenic mice but not in M14M mice. These results suggest that the high sCD14 concentration may account for less marked liver damage in M14M mice. Increase in the challenge dose of LPS (2 microg per mouse) resulted in increased lethality of M14M mice without liver damage. The levels of endothelial cell leukocyte adhesion molecule (ELAM)-1 mRNA expression in several organs in M14M mice 1-3h after LPS challenge were, however, lower than those in nontransgenic mice. The high sCD14 concentration may stimulate endothelial cell activation, which may account for lethality without liver damage in M14M mice. Thus, CD14 is involved in both the priming and induction phases as well as lethality in P. acnes-LPS system.

Surfactant protein A inhibits alveolar macrophage cytokine production by CD14-independent pathway

The lung collectin surfactant protein A (SP-A) has both anti-inflammatory and prophagocytic activities. We and others previously showed that SP-A inhibits the macrophage production of tumor necrosis factor (TNF)-alpha stimulated by the gram-negative bacterial component LPS. We propose that SP-A decreases the production of proinflammatory cytokines by alveolar macrophages via a CD14-independent mechanism. SP-A inhibited LPS-simulated TNF-alpha production in rat and mouse macrophages in the presence and absence of serum (72% and 42% inhibition, respectively). In addition, SP-A inhibited LPS-induced mRNA levels for TNF-alpha, IL-1 alpha, and IL-1 beta as well as NF-kappa B DNA binding activity. SP-A also diminished ultrapure LPS-stimulated TNF-alpha produced by wild-type and CD14-null mouse alveolar macrophages by 58% and 88%, respectively. Additionally, SP-A inhibited TNF-alpha stimulated by PMA in both wild-type and TLR4-mutant macrophages. These data suggest that SP-A inhibits inflammatory cytokine production in a CD14-independent manner and also by mechanisms independent of the LPS signaling pathway.

High expression of the CD14 gene and interleukin-1β gene in the liver and lungs of cirrhotic rats after partial hepatectomy

BACKGROUND

A hepatic resection is invasive for cirrhotic patients because postoperative complications, such as hepatic disturbance sometimes resulting in hepatic failure and pulmonary disturbances, are frequent and serious. We investigated here the alteration of the CD14 and inflammatory cytokine genes expressed in the liver and lungs after partial hepatectomy (PH) of a cirrhotic rat model to help elucidate the pathophysiological change occurring during the postoperative course of hepatectomized cirrhotic patients.

MATERIALS AND METHODS

Wistar rats were orally administrated carbon tetrachloride once a week for 14 weeks to induce liver cirrhosis. In comparison with cirrhotic and normal rats, we analyzed the expression of the CD14, tumor necrosis factor-alpha, and interleukin (IL)-1beta genes in remnant liver and whole lung tissue during 48 h after 30% partial hepatectomy with Northern blottings and measured asparatate aminotransferase (AST) in serum for evaluation of postoperative hepatic injury. Gadolinium chloride (GdCl3; 7 mg/kg body weight) was intravenously injected 24 h before partial hepatectomy to suppress Kupffer cells (KC) activation.

RESULTS

The expression of the CD14 and IL-1beta genes moderately increased at 6 h and peaked at 12 h in parallel with the time course of AST values after PH only in cirrhotic rats. GdCl(3) significantly inhibited the elevation of AST similar to the inhibition of the expression of the CD14 and IL-1beta genes after PH. In addition, the expression of these genes showed marked enhancement in the lungs of the cirrhotic hepatectomy model.

CONCLUSIONS

KC activation was responsible for hepatic injury after PH, and the CD14 system appeared to be an early trigger for KC activation followed by induction of inflammatory cytokine IL-1beta synthesis leading to hepatic injury. Furthermore, the CD14 system was suggested to participate in respiratory disturbances after hepatectomy in cirrhosis.

The immunomodulatory effects of the herbicide simazine on murine macrophage functions in vitro

We examined the immunomodulating effects of simazine, a triazine herbicide, on murine peritoneal macrophages after in vitro pre-exposure. When thioglycollate-elicited macrophages pre-exposed to simazine were stimulated with lipopolysaccharide (LPS), the antitumor activity induced by LPS was suppressed by simazine. Simazine also inhibited poly I:C-induced antiviral activity and interferon (IFN) production in macrophages. In addition, the production of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) which have been known to be major effector molecules in macrophage-mediated cytotoxicity was decreased by simazine pretreatment in a dose-dependent manner. However, simazine had little effect on phagocytosis and the level of hydrogen peroxide (H(2)O(2)), interleukin-1 (IL-1) and IL-6 by LPS-stimulated macrophages. Taken together, these data indicate that simazine has a differential immunomodulating effect on macrophage secretory and cellular activities.

Activation of human and mouse Kupffer cells by lipopolysaccharide is mediated by CD14

Upregulation of CD14 in Kupffer cells has been implicated in the pathogenesis of several forms of liver injury, including alcoholic liver disease. However, it remains unclear whether CD14 mediates lipopolysaccharide (LPS) signaling in this specialized liver macrophage population. In this series of experiments, we determined the role of CD14 in LPS activation of Kupffer cells by using several complementary approaches. First, we isolated Kupffer cells from human livers and studied the effects of anti-CD14 antibodies on LPS activation of these cells. Kupffer cells were incubated with increasing concentrations of LPS in the presence and absence of recombinant human LPS binding protein (LBP). With increasing concentrations of LPS, human Kupffer cell tumor necrosis factor-alpha (TNF-alpha) production (a marker for Kupffer cell activation) increased in a dose-dependent manner in the presence and absence of LBP. In the presence of anti-human CD14 antibodies, the production of TNF-alpha was significantly diminished. Second, we compared LPS activation of Kupffer cells isolated from wild-type and CD14 knockout mice. Kupffer cells from CD14 knockout mice produced significantly less TNF-alpha in response to the same amount of LPS. Together, these data strongly support a critical role for CD14 in Kupffer cell responses to LPS.

Polo-like kinase (PLK) expression in endometrial carcinoma

Polo-like kinase (PLK) is a cell cycle-regulated, cyclin-independent serine/threonine protein kinase. Recent reports have shown a critical role for PLK during tumorigenesis. To explore whether PLK plays a general role as a tumor marker of endometrial carcinomas, we examined the expression of PLK mRNA and protein in endometrial carcinomas and normal endometrium, and analyzed the relationship between PLK protein expression and malignant potential. We found that PLK mRNA was expressed in all specimens from endometrial carcinoma patients using RT-PCR methods, although some specimens from normal endometria were negative. Immunohistochemically, most of the PLK was found in the cytoplasm (around the nucleus), and partly in the nucleus of endometrial carcinoma glands and also secreted tissues from endometrial carcinoma glands. PLK was expressed at the basement membrane of carcinoma glands and partly expressed in the head portion of papillary carcinoma tissues. There was a significant correlation between percentages of PLK-positive cells and histological grade of endometrial carcinoma (P<0.0001). However, the expression of proliferating cell nuclear antigen and Ki-67 was independent of PLK expression. Moreover, we noted that PLK is strongly expressed in invading carcinoma cells. PLK expression could reflect the degree of malignancy and proliferation in endometrial carcinoma. Thus, in addition to being of diagnostic value, modulation of PLK activity in the tumors by chemotherapeutic agents or gene therapy may prove to be of therapeutic value.

Prevention of endotoxin-induced lethality in mice by calmodulin kinase activator

Porphyromonas gingivalis strain 381 lipid A showed lower activity in inducing interleukin (IL)-1alpha and IL-1beta production and cytokine mRNA expression than synthetic Escherichia coli lipid A (compound 506) in alveolar macrophages of C57BL/6 mice. Both the lipid As induced tumor necrosis factor alpha in alveolar macrophages and IL-6 in peritoneal macrophages. A calmodulin (CaM) antagonist, W-7, inhibited IL-1beta production and its mRNA expression induced by P. gingivalis lipid A but not compound 506 in alveolar macrophages. A CaM kinase activator reduced the induction of IL-1beta in the serum of mice when administered with compound 506, and protected the mice against the lethal toxicity. The modulation of a variety of intracellular enzymes including the CaM kinase may result in clinical control of endotoxic sepsis.

Estrogen is involved in early alcohol-induced liver injury in a rat enteral feeding model

The aim of this study was to investigate whether reduction in blood estrogen by removal of the ovaries would decrease the sensitivity of female rats to early alcohol-induced liver injury using an enteral ethanol feeding model, and if so, whether estrogen replacement would compensate. Livers from ovariectomized rats with or without estrogen replacement after 4 weeks of continuous ethanol exposure were compared with nonovariectomized rats in the presence or absence of ethanol. Ethanol increased serum alanine transaminase (ALT) levels from 30 +/- 6 to 64 +/- 7 U/L. This effect was blocked by ovariectomy (31 +/- 7) and totally reversed by estrogen replacement (110 +/- 23). Ethanol increased liver weight and fat accumulation, an effect that was minimized by ovariectomy and reversed partially by estrogen replacement. Infiltrating leukocytes were increased 6. 7-fold by ethanol, an effect that was blunted significantly by ovariectomy and reversed by estrogen replacement. Likewise, a similar pattern of changes was observed in the number of necrotic hepatocytes. Blood endotoxin and hepatic levels of CD14 messenger RNA (mRNA) and protein were increased by ethanol. This effect was blocked in ovariectomized rats and elevated by estrogen replacement. Moreover, Kupffer cells isolated from ethanol-treated rats with estrogen replacement produced more tumor necrosis factor alpha (TNF-alpha) than those from control and ovariectomized rats. It is concluded, therefore, that the sensitivity of rat liver to alcohol-induced injury is directly related to estrogen, which increases endotoxin in the blood and CD14 expression in the liver, leading to increased TNF-alpha production.

Inhibition of osteoblastic cell differentiation by lipopolysaccharide extract from Porphyromonas gingivalis

Lipopolysaccharide from Porphyromonas gingivalis (P-LPS), an important pathogenic bacterium, is closely associated with inflammatory destruction of periodontal tissues. P-LPS induces the release of cytokines and local factors from inflammatory cells, stimulates osteoclastic-cell differentiation, and causes alveolar bone resorption. However, the effect of P-LPS on osteoblastic-cell differentiation remains unclear. In this study, we investigated the effect of P-LPS extract prepared by the hot-phenol-water method, on the differentiation of primary fetal rat calvaria (RC) cells, which contain a subpopulation of osteoprogenitor cells, into osteoblastic cells. P-LPS extract significantly inhibited bone nodule (BN) formation and the activity of alkaline phosphatase (ALPase), an osteoblastic marker, in a dose-dependent manner (0 to 100 ng of P-LPS extract per ml). P-LPS extract (100 ng/ml) significantly decreased BN formation to 27% of the control value and inhibited ALPase activity to approximately 60% of the control level on days 10 to 21 but did not affect RC cell proliferation and viability. P-LPS extract time-dependently suppressed the expression of ALPase mRNA, with an inhibitory pattern similar to that of enzyme activity. The expression of mRNAs for osteocalcin and osteopontin, matrix proteins related to bone metabolism, was markedly suppressed by P-LPS extract. Furthermore, P-LPS extract increased the expression of mRNAs for CD14, LPS receptor, and interleukin-1beta in RC cells. These results indicate that P-LPS inhibits osteoblastic-cell differentiation and suggest that LPS-induced bone resorption in periodontal disease may be mediated by effects on osteoblastic as well as osteoclastic cells.

Expression of CD14 by hepatocytes: upregulation by cytokines during endotoxemia

Studies were undertaken to examine hepatocyte CD14 expression during endotoxemia. Our results show that lipopolysaccharide (LPS) treatment in vivo caused a marked upregulation in CD14 mRNA and protein levels in rat hepatocytes. Detectable increases in mRNA were seen as early as 1.5 h after LPS treatment; these increases peaked at 20-fold by 3 h and returned to baseline levels by 24 h. In situ hybridization localized the CD14 mRNA expression to hepatocytes both in vitro and in vivo. Increases in hepatic CD14 protein levels were detectable by 3 h and peaked at 12 h. Hepatocytes from LPS-treated animals expressed greater amounts of cell-associated CD14 protein, and more of the soluble CD14 was released by hepatocytes from LPS-treated rats in vitro. The increases in hepatocyte CD14 expression during endotoxemia occurred in parallel to increases of CD14 levels in plasma. To provide molecular identification of the hepatocyte CD14, we cloned the rat liver CD14 cDNA. The longest clone consists of a 1,591-bp insert containing a 1,116-bp open reading frame. The deduced amino acid sequence is 372 amino acids long, has 81.8 and 62.8% homology to the amino acid sequences of mouse and human CD14, respectively, and is identical to the rat macrophage CD14. The expressed CD14 protein from this clone was functional, as indicated by NF-kappaB activation in response to LPS and fluorescein isothiocyanate-LPS binding in CHO cells stably transfected with rat CD14. A nuclear run-on assay showed that CD14 transcription rates were significantly increased in hepatocytes from LPS-treated animals, indicating that the upregulation in CD14 mRNA levels observed in rat hepatocytes after LPS treatment is dependent, in part, on increased transcription. In vitro and in vivo experiments indicated that interleukin-1beta and/or tumor necrosis factor alpha participate in the upregulation of CD14 mRNA levels in hepatocytes. Our data indicate that hepatocytes express CD14 and that hepatocyte CD14 mRNA and protein levels increase rapidly during endotoxemia. Our observations also support the idea that soluble CD14 is an acute-phase protein and that hepatocytes could be a source for soluble CD14 production.

Normal reproductive and macrophage function in Pem homeobox gene-deficient mice

Interaction between germ cells and the supporting somatic cells guides many of the differentiative processes of gametogenesis. The expression pattern of the Pem homeobox gene suggests that it may mediate specific inductive events in murine reproductive tissues. During gestation, Pem is expressed in migrating and early postmigratory primordial germ cells, as well as in all embryo-derived extraembryonic membranes. Pem expression ceases in the germline after Embryonic Day 14 in both sexes and then reappears postnatally in the supporting cells of the gonad. In mature mice, Pem is produced by testicular Sertoli cells during stages VI-VIII of spermatogenesis and transiently by ovarian granulosa cells lining periovulatory follicles. Despite this tightly regulated reproductive expression pattern, mice with a targeted mutation in Pem have normal fecundity, with no detectable alteration in extraembryonic testicular or ovarian development or function. We also show that Pem is expressed throughout embryonic and adult development in a subset of a tissue-specific class of macrophages, Kupffer cells, as well as in a localized fraction of cells in macrophage cell lines. Although the number of Pem-positive Kupffer cells increases in mice treated with lipopolysaccharide, loss of Pem does not detectably interfere with the cells' ability to induce iNOS expression, demonstrating this Kupffer cell function does not require Pem. No differences were observed between Pem-knockout mice in 129, C57BL6/J, or mixed genetic backgrounds. Together, these data show that Pem is dispensable for embryonic and postnatal development, gonadal function, and Kupffer cell activation, perhaps due to compensatory expression of a similar homeobox gene.