Anti-inflammatory and Insulin Signaling Phenotype Induced by Repeated Lipopolysaccharide Stimulation in 3T3-L1 Adipocytes

BACKGROUND/AIM

Lipopolysaccharide (LPS) is thought to be a causative agent of type 2 diabetes, because it has been shown that a single LPS stimulation in vitro induces chronic inflammation and reduces insulin signaling in adipocytes. However, oral LPS administration prevents type 2 diabetes, and this effect does not correspond to a single LPS adipocyte stimulation. In this study, the response of adipocytes to single and repeated stimulation with LPS was examined.

MATERIALS AND METHODS

3T3-L1 cells were differentiated into adipocytes and stimulated with LPS once or thrice every 24 h. The expression levels of inflammatory and anti-inflammatory factors and insulin sensitivity-related factors were measured.

RESULTS

Single stimulation with LPS increased the mRNA and protein expression of inflammatory factors (interleukin-6 and monocyte chemotactic protein 1), but this increase was inhibited by repeated stimulation. In contrast, the mRNA expression levels of anti-inflammatory factors (proliferator-activated receptor γ and peroxisome proliferator-activated receptor gamma coactivator1 α) were increased by repeated LPS stimulation. Additionally, the mRNA expression levels of insulin sensitivity-related factors (glucose transporter type 4, insulin receptor, insulin receptor substrate 1 and thymoma viral proto-oncogene 2) in adipocytes were increased upon repeated LPS stimulation.

CONCLUSION

Repetitive LPS stimulation, unlike single stimulation of adipocytes, upregulates anti-inflammatory and insulin signaling-related factors.

Effect of topical application of lipopolysaccharide on contact hypersensitivity

Lipopolysaccharide (LPS) is the principal component of the outer membrane of gram-negative bacteria. The prior oral administration of LPS attenuates inflammatory responses, such as intestinal injury and atopic dermatitis, in mouse models; however, the underlying mechanism remains unclear. Here, we examined the effect of topical LPS application on allergic contact dermatitis and its mechanism of action using a murine contact hypersensitivity (CHS) model. Prolonged LPS application to the skin significantly suppressed 2,4-dinitrofluorobenzene (DNFB)-induced CHS. LPS application to the skin also reduced the phagocytosis of fluorescein isothiocyanate (FITC)-dextran by Langerhans and dendritic cells. Cutaneous cell migration into the skin-draining lymph nodes (LNs) induced by FITC painting was reduced by LPS application. During the CHS response, DNFB application induced T-cell proliferation and inflammatory cytokine production in skin-draining LNs, whereas prolonged LPS application inhibited DNFB-induced T-cell growth and interferon gamma production, indicating suppression of DNFB-induced sensitization. These results suggest that prolonged LPS application suppressed DNFB-induced sensitization and subsequently CHS response. Our findings imply that topical application of LPS may prevent allergic dermatitis such as CHS.

Prevention of Diabetes-Associated Cognitive Dysfunction Through Oral Administration of Lipopolysaccharide Derived From Pantoea agglomerans

Diabetes-related cognitive dysfunction (DRCD) is a serious complication induced by diabetes. However, there are currently no specific remedies for DRCD. Here, we show that streptozotocin-induced DRCD can be prevented without causing side effects through oral administration of lipopolysaccharide (LPS) derived from Pantoea agglomerans. Oral administration of LPS (OAL) prevented the cerebral cortex atrophy and tau phosphorylation induced by DRCD. Moreover, we observed that neuroprotective transformation of microglia (brain tissue-resident macrophages) is important for preventing DRCD through OAL. These findings are contrary to the general recognition of LPS as an inflammatory agent when injected systemically. Furthermore, our results strongly suggest that OAL promotes membrane-bound colony stimulating factor 1 (CSF1) expression on peripheral leukocytes, which activates the CSF1 receptor on microglia, leading to their transformation to the neuroprotective phenotype. Taken together, the present study indicates that controlling innate immune modulation through the simple and safe strategy of OAL can be an innovative prophylaxis for intractable neurological diseases such as DRCD. In a sense, for modern people living in an LPS-depleted environment, OAL is like a time machine that returns microglia to the good old LPS-abundant era.

Oral Administration of Lipopolysaccharide Prevents Cognitive Impairment in Streptozotocin-induced Diabetic Mice in a Blood Glucose-independent Manner

BACKGROUND/AIM

Diabetes is a risk factor for dementia. However, no radical preventive method for diabetes-associated dementia has yet been developed. Our previous study revealed that oral administration of lipopolysaccharide (LPS) prevents high-fat diet-induced cognitive impairment. Therefore, we investigated here whether oral administration of LPS (OAL) could also prevent diabetes-associated dementia.

MATERIALS AND METHODS

Diabetic mice were produced by intraperitoneal administration of streptozotocin (STZ), and then mice were orally administered LPS. Cognitive ability was evaluated using the Morris water maze, and gene expression was analyzed in isolated microglia.

RESULTS

OAL prevented STZ-induced diabetic cognitive impairment, but did not affect blood glucose levels. Moreover, OAL promoted the expression of neuroprotective genes in microglia, such as heat shock protein family 40 (HSP40) and chemokine CCL7.

CONCLUSION

OAL prevents diabetes-associated dementia, potentially via promotion of HSP40 and CCL7 expression in microglia.

Prevention of streptozotocin‑induced Neuro‑2a cell death by C8‑B4 microglia transformed with repetitive low‑dose lipopolysaccharide

Diabetes‑associated neuronal dysfunction (DAND) is one of the serious complications of diabetes, but there is currently no remedy for it. Streptozotocin [2‑deoxy‑2‑(3‑methy1‑3‑nitrosoureido) D‑glucopyranose; STZ] is one of the most well‑established diabetes inducers and has been used in vivo and in vitro DAND models. The aim of the present study was to demonstrate that C8‑B4 microglia transformed by the stimulus of repetitive low‑dose lipopolysaccharide (LPSx3‑microglia) prevent STZ‑induced Neuro‑2a neuronal cell death in vitro. The ELISA results showed that neurotrophin‑4/5 (NT‑4/5) secretion was promoted in LPSx3‑microglia and the cell viability assay with trypan blue staining revealed that the culture supernatant of LPSx3‑microglia prevented STZ‑induced neuronal cell death. In addition, reverse transcription‑quantitative PCR showed that neurons treated with the culture supernatant of LPSx3‑microglia promoted the gene expression of B‑cell lymphoma‑extra large and glucose‑dependent insulinotropic polypeptide receptor. Furthermore, the inhibition of tyrosine kinase receptor B, a receptor of NT‑4/5, suppressed the neuroprotective effect of LPSx3‑microglia. Taken together, the present study demonstrated that LPSx3‑microglia prevent STZ‑induced neuronal death and that NT‑4/5 may be involved in the neuroprotective mechanism of LPSx3‑microglia.

A Novel Anti-inflammatory Phenotype Transformed by Repetitive Low-dose Lipopolysaccharide in Primary Peritoneal Tissue-resident Macrophages

BACKGROUND/AIM

Our previous studies suggested that oral administration of lipopolysaccharide (LPS) regulates the progression of various diseases via transformation of tissue-resident macrophages (MΦ). Recently, we characterized microglia transformed by repetitive low-dose LPS treatment (REPELL-microglia) in vitro, and this response was similar to that observed in response to oral administration of LPS in vivo. Here, we examined the characteristics of peritoneal tissue-resident MΦ (pMΦ) transformed by repetitive low-dose LPS treatment (REPELL-pMΦ).

MATERIALS AND METHODS

Primary pMΦ were treated with low-dose LPS (1 ng/ml) three times; subsequently, phagocytic activity and gene expression were evaluated.

RESULTS

REPELL-pMΦ exhibited high phagocytic activity and elevated expression of Arg1, Gipr, Gdnf, and Fpr2. The gene expression profiles observed in REPELL-pMΦ were distinct from those of REPELL-microglia.

CONCLUSION

REPELL-pMΦ have the potential to promote clearance of xenobiotics and to suppress inflammation. The present study also demonstrates the diversity of tissue-resident MΦ transformation that reflect their tissue origin.

Enhanced Effect of Hyaluronan and Elastin Synthesis in Fibroblasts Through Lipopolysaccharide-activated Macrophages

BACKGROUND/AIM

The functions of macrophages change in response to environmental factors such as lipopolysaccharide (LPS). LPS derived from Pantoea agglomerans (LPSp) is involved in macrophage activation and tissue repair when administered dermally. LPSp-activated macrophages may be useful for restoring and maintaining homeostasis of the skin.

MATERIALS AND METHODS

Phorbol myristate acetate-treated human monocytes (THP-1 cells) were activated with LPSp. The medium of LPSp-activated THP-1 cells was added to normal human dermal fibroblasts (NHDF cells). After 24 h, the expression of hyaluronan (HA) synthase (HAS)2, hyaluronidase (HYAL)1, and tropoelastin in NHDF cells was analyzed using quantitative real-time PCR.

RESULTS

The expression of HAS2 and tropoelastin was significantly increased, but that of HYAL1 was significantly decreased. It was demonstrated that the abilities of HA and elastin synthesis in NHDF cells increased through LPSp-activated THP-1 cells.

CONCLUSION

LPSp-activated macrophages may be useful for enhancing the abilities of HA and elastin synthesis in fibroblasts, subsequently improving dysfunction and reducing various age-related disorders.

Attempt to Construct an In Vitro Model of Enhancement of Macrophage Phagocytosis Via Continuous Administration of LPS

BACKGROUND

Continuous oral administration of lipopolysaccharide (LPS) enhances the phagocytic ability of macrophages, which is useful for preventing various diseases. Here, we attempted to create an in vitro model of continuous administration of LPS.

MATERIALS AND METHODS

RAW264.7 cells were stimulated with LPS three times every 24 h (repeated stimulation), and phagocytic ability and inflammatory cytokine [interleukin-6 (IL6) and tumor necrosis factor-α (TNFα)] production were measured.

RESULTS

The phagocytic ability was increased by a single stimulation with LPS and was maintained by repeated stimulation. IL6 production increased with a single stimulation with LPS; however, IL6 production by repeated stimulation with LPS was comparable to that of non-stimulation with LPS. On the other hand, the amount of TNFα was significantly increased by single and repeated stimulation with LPS.

CONCLUSION

Repeated stimulation with LPS in RAW264.7 cells triggered a phenotype that was similar to that of macrophages after continuous oral administration of LPS. This suggests that this study model may reproduce the enhancement of macrophage phagocytosis, an effect afforded by continuous oral administration of LPS.

A unique hybrid characteristic having both pro- and anti-inflammatory phenotype transformed by repetitive low-dose lipopolysaccharide in C8-B4 microglia

Although lipopolysaccharide (LPS) is regarded as an inducer of inflammation, previous studies have suggested that repetitive low-dose LPS has neuroprotective effects via immunomodulation of microglia, resident macrophages of brain. However, microglia transformed by the stimulus of repetitive low-dose LPS (REPELL-microglia) are not well characterized, whereas microglia transformed by repetitive high-dose LPS are well studied as an endotoxin tolerance model in which the induction of pro-inflammatory molecules is suppressed. In this study, to characterize REPELL-microglia, the gene expression and phagocytic activity of REPELL-microglia were analyzed with the murine C8-B4 microglia cell line. The REPELL-microglia were characterized by a high expression of pro-inflammatory molecules (Nos2, Ccl1, IL-12B, and CD86), anti-inflammatory molecules (IL-10, Arg1, Il13ra2, and Mrc1), and neuroprotective molecules (Ntf5, Ccl7, and Gipr). In addition, the phagocytic activity of REPELL-microglia was promoted as high as that of microglia transformed by single low-dose LPS. These results suggest the potential of REPELL-microglia for inflammatory regulation, neuroprotection, and phagocytic clearance. Moreover, this study revealed that gene expression of REPELL-microglia was distinct from that of microglia transformed by repetitive high-dose LPS treatment, suggesting the diversity of microglia transformation by different doses of LPS.

Subchronic (90-day) toxicity assessment of Somacy-FP100, a lipopolysaccharide-containing fermented wheat flour extract from Pantoea agglomerans

Pantoea agglomerans is a Gram-negative bacterium that is ubiquitous in the environment, colonizing animals, humans, and numerous plants, including cotton and wheat. A lipopolysaccharide-containing fermented wheat flour extract from P. agglomerans (Somacy-FP100) is proposed for use as a food ingredient for individuals seeking foods for healthy aging. Previously published genotoxicity studies with Somacy-FP100 reported its lack of genotoxicity in vitro, but a subchronic toxicity study has not yet been performed. Therefore, to demonstrate the safety of Somacy-FP100 for use as a food ingredient, a 90-day oral (gavage) toxicity study in rats was conducted. Male and female Han Wistar rats were administered vehicle (control) or Somacy-FP100 at 500, 1500, or 4500 mg/kg body weight/day at a dose volume of 10 mL/kg body weight, for at least 90 days. No test article-related adverse clinical signs or effects on body weight, food consumption, or clinical pathology were observed, and there were no macroscopic or microscopic findings related to the test article. Therefore, 4500 mg/kg body weight/day (the highest dose tested and highest feasible dose) was established as the no-observed-adverse-effect level. This absence of subchronic toxicity, in addition to the previously reported lack of genotoxicity, demonstrates the safety of Somacy-FP100 for use as a food ingredient.

The Effect of Lipopolysaccharide-containing Moisturizing Cream on Skin Care in Patients With Mild Atopic Dermatitis

BACKGROUND/AIM

Recently, the prevalence of atopic dermatitis (AD) has increased in developed countries. This study aimed to examine the usefulness of a moisturizing cream containing lipopolysaccharide derived from Pantoea agglomerans (LPSp) in patients with mild AD.

PATIENTS AND METHODS

A moisturizing cream containing LPSp or its placebo was randomly assigned and continuously used for 4 weeks in patients with mild AD. AD severity was evaluated in a double-blind manner by a dermatologist using the Eczema Area and Severity Index (EASI) score and by the patients' self-evaluation of itching and skin condition using a visual analog scale (VAS).

RESULTS

Although there was no difference in the EASI score between the two groups, the VAS scores showed significantly greater symptom alleviation in the LPSp group than in the placebo group.

CONCLUSION

A moisturizing cream containing LPSp may be effective for routine skin care and could help alleviate symptoms of mild AD.

Dewaxed Brown Rice Feed Improves Fatty Liver in Obese and Diabetic Model Mice

BACKGROUND/AIM

Dewaxed brown rice has macrophage activation ability via TLR4 and contains a high amount of lipopolysaccharides (LPS). It is expected that dewaxed brown rice can help prevent lifestyle diseases. In this study, the anti-obesity effect of dewaxed brown rice was investigated using obese and diabetic model mice.

MATERIALS AND METHODS

Dewaxed brown rice and white rice were polished and powdered by Toyo Rice Co. Diet pellets were prepared (AIN-93) with 50% dewaxed brown rice or white rice powder and fed to type II diabetic model KK-Ay mice for 10 weeks. Weight and fasting blood glucose were measured every week, and whole blood and liver was collected on the final day for the evaluation of biochemical data.

RESULTS

A 20% reduction in body weight was found in the dewaxed brown rice feed and white rice feed groups compared to the normal feed group. Fasting blood glucose increased in the normal-diet group, but on the other hand, the blood glucose in the white rice and the dewaxed brown rice feed group was almost constant. Dewaxed brown rice feed group of plasma ALT and AST, liver TG and T-CHO were significantly lower than that of the control and the white rice feed group.

CONCLUSION

Dewaxed brown rice feed has an anti-obesity effect to suppress increasing body weight, fasting blood glucose, and an effect of suppressing fatty liver.

Oral administration of Pantoea agglomerans-derived lipopolysaccharide prevents development of atherosclerosis in high-fat diet-fed apoE-deficient mice via ameliorating hyperlipidemia, pro-inflammatory mediators and oxidative responses

Pantoea agglomerans (P. agglomerans) is a Gram-negative bacterium that grows symbiotically with various edible plants, and the oral or sublingual administration of lipopolysaccharide derived from P. agglomerans (LPSp) have been suggested to contribute to prevention of immune-related diseases. Our previous study indicated that orally administered LPSp was shown to exhibit an LDL-lowering effect in hyperlipidemic volunteers; however, a preventive effect of LPSp on atherosclerosis is unclear. The present study attempted to evaluate the anti-atherosclerotic effect by LPSp in a mouse model of high-fat diet (HFD)-induced atherosclerosis. For 16 weeks, apoE-deficient mice were fed an HFD and received drinking water containing LPSp (0.3 or 1 mg/kg body weight/day). The results showed that the orally administered LPSp decreased body weight. A significant reduction in atherosclerotic plaque deposition was observed even with the lower dose of LPSp. The biochemical analyses showed that LPSp markedly improved glucose tolerance and reduced plasma LDL and oxidized LDL levels. In addition, LPSp significantly reduced the production of pro-inflammatory mediators including MCP-1 (in the plasma), TNF-α and IL-6 (in the colon), and decreased the oxidative burst activities in the peripheral blood sample. Taken together, these results suggest the possibility that oral administration of LPSp can effectively ameliorate HFD-induced hyperlipidemia and inflammatory/oxidative responses to prevent atherosclerosis and related metabolic disorders.

Effects of 3 months continuous intake of supplement containing Pantoea agglomerans LPS to maintain normal bloodstream in adults: Parallel double-blind randomized controlled study

In this study, the effects on the maintenance of normal bloodstream by lipopolysaccharide (LPS) were investigated in the parallel-group randomized double-blind study using supplement containing Pantoea agglomerans LPS (201.5 μg/tablet as LPS). Screening was previously performed in the implementation of the study. Adult males and females with normal value to borderline (healthy subjects) in the hematologic parameters, for which reference values were given, were chosen in this study. The period of ingestion of the supplement was 3 months. As the result, a significant decrease in the rate of change (the ratio when the baseline was 1) of HbA1c, which is a glycative stress marker, was found in the group which ingested LPS supplement after 3 months. Also, a significant increase in the number of fingertip capillary vessels was found compared with the control group. From these results, the effects of the maintenance of bloodstream by ingestion of LPS were shown.

Lipopolysaccharides Derived from Pantoea agglomerans Can Promote the Phagocytic Activity of Amyloid β in Mouse Microglial Cells

BACKGROUND/AIM

Recent studies reported that lipopolysaccharide (LPS) exhibits beneficial effects on prevention of immune-related diseases by activating macrophages. We previously demonstrated that pre-treatment with LPS derived from Pantoea agglomerans (LPSp) activated amyloid β (Aβ) phagocytosis in mouse primary microglia. In the present study, we further examined the promotory effect on phagocytosis of phagocytic particles in the C8-B4 microglia cell line.

MATERIALS AND METHODS

Phagocytic analysis of C8-B4 cells was evaluated using phagocytic particles (latex beads or HiLyte™ Fluor 488-conjugated Aβ_1-42).

RESULTS

The phagocytic activity of latex beads was dependent on the concentration of beads and incubation time. LPSp, at as low as 100 pg/ml, significantly increased phagocytosis against the beads. In the experiment of Aβ_1-42 phagocytosis, LPSp significantly increased Aβ phagocytic activity.

CONCLUSION

LPSp treatment was confirmed to enhance Aβ_1-42 phagocytosis by mouse microglia. It is suggested that the use of LPSp may be a potential promising candidate for the prevention of Alzheimer's disease.

Improvement Effect of Dewaxed Brown Rice on Constipation in Antibiotic-treated Mice

BACKGROUND/AIM

A decrease in gastrointestinal motility causing weakened lipopolysaccharide (LPS) - toll-like receptor (TLR)4 signaling along with a decline in the number of enteric bacteria is known to be a cause of constipation due to the administration of antibiotics. A new type of brown rice with its wax layer removed, resulting in quick-cooking and tasty product, contains 100-times more LPS than polished white rice. In this study, the improvement effect on constipation due to intake of dewaxed brown rice was examined.

MATERIALS AND METHODS

Dewaxed brown rice was prepared at Toyo Rice from brown rice. Mice were given powdered feed to which powdered rice containing 0-50% of dewaxed brown rice was added. Antibiotics were administered for 10 or 27 days in drinking water containing vancomycin, metronidazole and neomycin. LPS, used as a control, was freely provided in drinking water. The defecation frequency, stool weight per hour and body weight were determined on the last day.

RESULTS

Although the 10-day administration of antibiotics reduced the stool weight per hour to half, the dewaxed brown rice and LPS groups showed a trend towards improvement at a level comparable to the group receiving no antibiotics. The body weight significantly decreased after the 27-day administration of antibiotics but was improved in the 50% dewaxed brown rice group at a level comparable to the group receiving no antibiotics. Though the defecation frequency and wet and dry stool weights per hour were reduced by as much as 50% in the group receiving antibiotics, a significant improvement in constipation was observed in the 50% dewaxed brown rice group.

CONCLUSION

As the improvement effect of dewaxed brown rice on body weight loss and constipation caused by the long-term administration of antibiotics has been confirmed in animal experimentation, the introduction of dewaxed brown rice as a staple food to patients under long-term antibiotic treatment may improve constipation.

Effect of Lipopolysaccharide Derived from Pantoea agglomerans on the Phagocytic Activity of Amyloid β by Primary Murine Microglial Cells

BACKGROUND/AIM

Monophosphoryl lipid A, lipopolysaccharide (LPS)-derived Toll-like receptor (TLR) 4 agonist, has been shown to be effective in the prevention of Alzheimer's disease (AD) by enhancing phagocytosis of amyloid β (Aβ) by brain microglia. Our recent study demonstrated that oral administration of LPS derived from Pantoea agglomerans (LPSp) activates peritoneal macrophages and enhances the phagocytic activity via TLR4 signaling pathway; however, the effect of LPSp on Aβ phagocytosis in microglia is still unknown.

MATERIALS AND METHODS

Primary microglial cells were isolated from adult mouse brain by enzymatic digestion, following myelin removal and magnetic separation of cluster of differentiation (CD) 11b. Phagocytic analysis of the primary microglia was measured by using HiLyte™ Fluor 488-conjugated Aβ1-42 RESULTS: Using our protocols, the average yield of isolated CD11b(+) cells was around 2.2×10(5) cells per brain. CD11b(+)CD45(+)CD39(+) cells were defined here as microglia. The phagocytic activity of Aβ1-42 by the isolated microglia was confirmed. LPSp (10 ng/ml) pre-treatment for 18 h significantly increased Aβ phagocytic activity.

CONCLUSION

The enhancement of Aβ1-42 phagocytosis by LPSp treatment in the primary mouse microglia was demonstrated for the first time.

Immunopotentiator from Pantoea agglomerans 1 (IP-PA1) Promotes Murine Hair Growth and Human Dermal Papilla Cell Gene Expression

BACKGROUND/AIM

The lipopolysaccharide (LPS)-like compound derived from Pantoea agglomerans (immunopotentiator from Pantoea agglomerans 1 (IP-PA1)) has been used not only as dietary supplement or cosmetic for humans, but also by Japanese veterinarians as an anti-tumor, anti-allergy, "keep a fine coat of fur" and hair growth-promoting functional food for dogs and cats. In the present study, we focused on the hair growth-promoting effects of IP-PA1 on a hair-shaved animal model and its mechanism of action. We also investigated its potential on gene expression after stimulating human dermal papilla cells with IP-PA1.

MATERIALS AND METHODS

The hair on the back of a C3H/HeN mouse was shaved and IP-PA1 was orally administered or applied to the skin. The status of hair growth was observed and recorded for 14 days. Skin was collected and histological tissue examination was performed with respect to hair growth status using hematoxylin and eosin staining. After IP-PA1 administration (2 and 10 μg/ml) to human dermal papilla cell culture system for 24 h, fibroblast growth factor-7 (FGF-7) and vascular endothelial growth factor (VEGF) mRNA expression were measured using real-time polymerase chain reaction (PCR) analysis.

RESULTS

IP-PA1, when given orally, showed a tendency to promote hair growth in mice. In addition, skin application also significantly promoted hair growth, while histopathological examinations further demonstrated hair elongation from dermal papilla cells. In the human dermal papilla cell culture system, significant FGF-7 and VEGF mRNA expressions were observed (p<0.05).

CONCLUSION

An underlying mechanism of gene expression by which IP-PA1 promotes hair growth was suggested to be different from that of medicine and traditional hair tonics, such as minoxidil and adenosine.

Dewaxed Brown Rice Contains a Significant Amount of Lipopolysaccharide Pointing to Macrophage Activation via TLRs

BACKGROUND/AIM

Oral ingestion of lipopolysaccharide (LPS) has been shown to be effective in diseases' prevention. Brown rice contains large amounts of LPS not actively consumed because of bad taste. Recently, a new type of brown rice with its wax layer removed has been produced. In this report, we measured the LPS content of this dewaxed rice and evaluated the function of innate immune activation on macrophages.

MATERIALS AND METHODS

Dewaxed brown rice and polished rice were prepared using the Saika-style rice polishing process. LPS content extracted using hot water from this sample was evaluated by the Limulus reaction and the activation of macrophage RAW246.7 cells was evaluated by nitric oxide (NO) production. In addition, toll-like receptors (TLRs) 2-, 4- and 9-induced human embryonic kidney (HEK) 293 cells were used for the confirmation of the activated pathway.

RESULTS

Mean LPS content in the 15 types of dewaxed brown rice was found to be 6.4±2.6 μg/g, while that of brown rice was 10.9±4.3 μg/g. The extract of dewaxed brown rice induced significant amounts of NO by RAW246.7 cells, while production was reduced to 1/6 by adding polymyxin B. The macrophage activating effect of dewaxed brown rice was 79- and 51-times higher than that of polished rice in TLR4- and 2-induced HEK 293 cells.

CONCLUSION

LPS content in dewaxed brown rice was found to be able to activate macrophages. This rice activated macrophages mainly via the TLR4 and, to a lesser extent, TLR2 pathways. It is suggested that dewaxed brown rice can be considered effective in allergy and cancer prevention.

Primed Activation of Macrophages by Oral Administration of Lipopolysaccharide Derived from Pantoea agglomerans

BACKGROUND/AIM

Bacterial lipopolysaccharide (LPS) is involved in the activation of the innate immune responses on monocytes/macrophages in vitro, and by intravenous injection. Although small quantities of LPS are usually found in traditional Chinese medicines, vegetables and fruits, the mode of action of orally administered LPS is still unclear.

MATERIALS AND METHODS

LPS derived from Pantoea agglomerans (LPSp) was orally administered to C3H/HeN or C3H/HeJ mice ad libitum.

RESULTS

The LPSp treatment enhanced phagocytosis by resident peritoneal macrophages of C3H/HeN mice but not of C3H/HeJ mice. This activation can be defined as primed activation because no augmentation of inflammatory cytokines production was detected. LPSp in peritoneal fluid was detected and successfully quantified. Moreover, the LPSp reduced the expression of avian reticuloendotheliosis viral oncogene-related B (RelB) in the macrophages without degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cell inhibitor, alpha (IκBα).

CONCLUSION

Orally administered LPSp can reach the peritoneum, and enhance phagocytosis via Toll-like receptor 4 signaling pathway in resident peritoneal macrophages.

Innate Immunity Activated by Oral Administration of LPSp Is Phylogenetically Preserved and Developed in Broiler Chickens

BACKGROUND

Oral administration of lipopolysaccharide (LPS), a major outer-membrane component of Gram-negative bacteria, has been found to prevent infection in mammals and fish. Oral administration of LPS is believed to increase phagocytic activity and promote cytokine production, thus associating it with priming. The present study aimed to elucidate the effect of oral administration of LPS in birds, which phylogenetically lie between fish and mammals, using chickens as a model.

MATERIALS AND METHODS

LPS derived from Pantoea agglomerans (LPSp) was added to the feed or water for oral administration to broiler chickens. For the survival assay and gene expression analysis (Genopal), LPSp was administered at a dose of 10 μg/kg of body weight (BW)/day. LPSp was administered at a dose of 0.2 μg/kg or 200 μg/kg to stimulate peripheral blood mononuclear phagocytosis (latex beads) and nitric oxide (NO) production.

RESULTS

LPSp (10 μg/kg BW/day) administration significantly inhibited mortality in broiler chickens on commercial farms. Furthermore, oral administration resulted in a transient increase in phagocytic activity and improved the ability to produce NO. On examining splenic cytokine induction following intraperitoneal administration of LPS derived from Escherichia coli (LPSe), we found significantly increased interleukin (IL)-1β mRNA expression.

CONCLUSION

Innate immunity activation in chickens, as seen in infection prevention, was induced by oral administration of LPSp. This infection prevention involved increased phagocytic activity and enhanced gene expression and appears to be a phylogenetically-preserved innate immunity mechanism.

Oral Administration of Lipopolysaccharide of Acetic Acid Bacteria Protects Pollen Allergy in a Murine Model

BACKGROUND/AIM

Lipopolysaccharide (LPS), a major component of the cell wall of Gram-negative bacteria, is known to possess strong immune-regulatory activity. We have found and reported the existence of biologically-active LPS in acetic acid bacteria. The LPS shows Limulus-positive activity and activation of macrophages to produce nitric oxide and tumor necrosis factor. In this study, we investigated the anti-allergic effect of an orally-administrated acetic acid bacteria extract containing LPS; the cedar pollinosis model was used.

MATERIALS AND METHODS

Acetic acid bacteria were isolated from various fruits by Nodai kaihen medium. Then, the anti-allergic effect of acetic acid bacteria extracts was investigated. BALB/c mice were immunized with a mixture of cedar pollen and alum into their peritoneal cavity; they also received additional immunizations of pollen to nasal cavity. After immunizing the mice with pollen into their nasal cavity to trigger an allergic reaction, the frequency of nose scratching was counted for 5 min.

RESULTS

The bacteria were cultured and prepared and the water-extract contained about 1-10 mg/ml of Limulus positive substances. The extract of acetic acid bacteria induced higher levels of interleukin (IL)-10 and FOXP3 mRNA expression in macrophages (RAW246.7 cell), as assessed by DNA microarray analysis. Oral administration of the acetic acid bacteria extract demonstrated significantly less scratching numbers than control water group with pollen immunization.

CONCLUSION

These results showed that LPS in acetic acid bacteria has the potential to protect from an allergic reaction, especially from cedar pollinosis.

Effects of the Subaleurone Layer of Rice on Macrophage Activation and Protection of Pollen Allergy in a Murine Model

BACKGROUND/AIM

Oral intake of lipopolysaccharide (LPS) has been demonstrated to be effective in the prevention of various diseases. We have found that the subaleurone layer of rice contains a large amount of LPS. The aim of this study was to evaluate the role of this layer in innate immunity.

MATERIALS AND METHODS

Using the Saika-style rice polishing process, a sbaleurone layer and the rice retaining a subaleurone layer and polished white rice were prepared from brown rice. Using hot-water extracts from rice, LPS content was measured by the Limulus reaction and the effect of activation of macrophages was evaluated on the basis of their phagocytic activity and nitric monoxide (NO) and tumor necrosis factor (TNF) production levels. Toll-like receptor (TLR)-2-, TLR-4- and TLR-9-transfected human embryonic kidney (HEK) cells were used to identify the activation pathway. An allergy mouse model was used to evaluate the prevention of pollen allergy.

RESULTS

When compared to polished white rice, rice retaining a subaleurone layer had a 6-fold increase in LPS and an increased macrophage activation when phagocytic activity and NO and TNF production were used as indices. TRL4 was the major pathway for such activation. Anti-allergy test by oral intake of subaleurone showed a significant preventive effect for pollen allergy.

CONCLUSION

Compared to polished white rice, rice retaining a subaleurone layer contained a high level of LPS with higher macrophage activation. Furthermore, oral administration of the rice demonstrated a preventive effect for pollen allergy, thus indicating its utility as a functional food that has a regulatory effect on innate immunity.

Usefulness of oral administration of lipopolysaccharide for disease prevention through the induction of priming in macrophages

Many publications show that macrophages are closely involved in etiology of diseases, such as cancer, diabetes, arteriosclerosis, and Alzheimer's disease. Recent studies show that waste products (e.g. dead cells, denatured proteins, oxidized lipids, and advanced glycation end-products) are the real causative agents of lifestyle-associated diseases. From the standpoint of health maintenance, macrophages eliminate foreign objects and waste products from an animal's body and appear to be quite important for maintaining homeostasis. There are two stages of activation of macrophages: one is priming and the other is the triggering stage with cytokine secretion. The priming stage of macrophages is an ostensibly functional stage without characteristic morphological changes and secretion of cytokines, but it functionally promotes clearance of waste products. In this review, we discuss the usefulness of oral administration of lipopolysaccharide (LPS) as a macrophage-priming agent for prevention/treatment of several diseases, including cancer. Moreover, the oral administration of LPS is safe. These observations suggest that LPS may be considered a vitamin-like substance with therapeutic properties.

Induction of nitric oxide production in RAW264.7 cells under serum-free conditions by O-antigen polysaccharide of lipopolysaccharide

BACKGROUND

Lipopolysaccharide derived from Pantoea agglomerans (LPSp) mainly consists of two aggregates, the high-molecular aggregate (HMM-LPSp) and the low-molecular aggregate (LMM-LPSp). The structural differences between HMM-LPSp and LMM-LPSp seem to depend on the length of the O-antigen polysaccharide because the lipid A regions of the two fractions are quite similar. In this study, we examined the biological activity of LPSp focusing on the O-antigen polysaccharide using HMM-LPSp and LMM-LPSp under serum-free conditions.

MATERIALS AND METHODS

The binding of LPSp to RAW264.7 cells under serum-free conditions was analyzed by flow cytometry using LPSp-conjugated fluorescein isothiocyanate (FITC-LPSp). The biological activities of HMM-LPSp and LMM-LPSp under serum-free conditions were evaluated by the nitric oxide production.

RESULTS

FITC-LPSp showed higher fluorescence intensity under serum-free than serum-containing conditions. HMM-LPSp induced higher nitric oxide production than LMM-LPSp under serum-free conditions.

CONCLUSION

The present study indicates that the reactivity of LPSp is affected by the O-antigen polysaccharide under serum-free conditions.

Orally administered LPS enhances head kidney macrophage activation with down-regulation of IL-6 in common carp (Cyprinus carpio)

Immunostimulants represent a promising aquaculture tool for enhancing disease and stress resistance in cultured fish. Moreover, the term and dose for acting immunostimulants is an important thing for fish farmer. This study investigated the immune parameters of common carp after oral administration of LPS (5, 10, 20 μg/kg/days) for 30 and 60 days, which is considered to be the proper time period for acting in aquaculture. Phagocytic and bactericidal activities of head kidney macrophages and serum lysozyme activities were significantly enhanced in LPS-fed carp. Orally administered LPS augmented the expression of interleukin (IL)-1β and TNF-α mRNAs but reduced the expression of IL-6 mRNA in head kidney. Although LPS was detected in the serum and liver after a high-dose (>15 mg/kg) oral administration, it was not detected by administered LPS-specific ELISA after a low-dose (<20 μg/kg) administration. It is speculated that orally administered LPS enhances the eliminating functions of head kidney macrophages with down-regulation of IL-6.

Reconsideration of macrophage and dendritic cell classification

It is well known that the activation of innate immune cells, especially antigen-presenting cells such as macrophages and dendritic cells, can ameliorate or exacerbate various diseases, including cancer. Currently, the macrophages and dendritic cells are categorized into several groups by their cell surface and intracellular molecules. However, the detailed classification of the differences between macrophages and dendritic cells has still not been established. Here, we summarized and reviewed the previous studies on the classification of macrophages and dendritic cells. In addition, the previous classification of monocytes, macrophages and dendritic cells is discussed based on our findings of macrophage activation, which has both conventional and plasmacytoid dendritic cell phenotype.

A mixture of Salacia oblonga extract and IP-PA1 reduces fasting plasma glucose (FPG) and low-density lipoprotein (LDL) cholesterol levels

At present, lifestyle-related diseases are one of the most critical health issues worldwide. It has been reported that lipopolysaccharide derived from a Gram-negative bacteria (IP-PA1) symbiotic with wheat exhibited several advantageous biological effects, such as the reduction of plasma glucose levels in NOD mice and low-density lipoprotein (LDL) levels in WHHL rabbits. In this study, the beneficial effects on plasma glucose and lipids of a tea (SI tea) consisting of IP-PA1 and Salacia (which contains an inhibitor of α-glucosidase) were investigated in the KK-Ay/TaJcl type 2 diabetic model mice and in human subjects with premetabolic syndrome in a double-blind, randomized study. SI tea significantly decreased plasma glucose levels in KK-Ay/TaJcl mice. A clinical trial of SI tea was performed with 41 subjects between the ages of 40 and 69, who belonged either to a high plasma glucose group (HG: FPG 100-125 mg/dl) or to a hyperlipidemia group (HL: TG ≥ 150 mg/dl, or LDL ≥ 120 mg/dl, or HDL < 40 mg/dl). These subjects ingested either Salacia without IP-PA1 (the control) or SI tea. Blood samples were collected at 0, 30, and 60 days after initiating SI tea treatment, and were measured for FPG, HbA1c, TG, LDL, and HDL. These results showed that SI tea reduced FPG and HbA1c more rapidly than the control in the HL group, and also significantly improved LDL and HDL levels in the HG group. Thus, SI tea may be helpful in preventing lifestyle-related diseases.

Anti-lipopolysaccharide factor evokes indirect killing of virulent bacteria in kuruma prawn

AIMS

Anti-lipopolysaccharide factor (ALF) is an antimicrobial peptide (AMP) and a key effector molecule of the innate immune system in crustaceans. However, little is known about the role of its indirect killing against bacteria. The possible regulatory role of this peptide (M-ALF) in kuruma prawns, Marsupenaeus japonicus, was investigated.

MATERIALS AND METHODS

The activities of M-ALF were investigated by antimicrobial activity in vitro and by experimental infection Vibrio penaeicida in vivo with ALF-knock down in kuruma prawn by systemically silencing M-ALF gene through the injection of gene-specific long double-stranded RNA with RNA interference.

RESULTS

Synthetic M-ALF had no direct antimicrobial activity against V. penaeicida, whereas ALF-silenced kuruma prawns had significantly higher mortality than untreated prawn after V. penaeicida infection. The data provide compelling evidence that M-ALF plays an indirect protective role against V. penaeicida infection, suggesting the idea that ALF acts as a cytokine-like regulatory molecule, as well as an effector molecule.

CONCLUSION

M-ALF has no direct activity against V. penaeicida, but might be a key molecule in cytokine-like gene regulation in crustaceans.

Oral administration of immunopotentiator from Pantoea agglomerans 1 (IP-PA1) improves the survival of B16 melanoma-inoculated model mice

To investigate the usefulness of the immunopotentiator from Pantoea agglomerans 1 (IP-PA1) as a supportive drug in melanoma therapy, we analyzed the immunological effects of IP-PA1 on melanoma-inoculated model mice. Oral administration of IP-PA1 increased the serum levels of tumor necrosis factor (TNF)-α at 2 h after the administration and interferon (IFN)-γ and IL-12 at 12 h after the administration in naïve BALB/cCrSlc mice as evaluated by ELISA. IP-PA1 did not affect the proliferation of melanoma cells directly determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Combinatory treatment of IP-PA1 with doxorubicin for 9 days increased the serum levels of IFN-γ and IL-12 by 71.0 and 15.3%, respectively, compared to the treatment of doxorubicin alone in melanoma-bearing C57BL/6NCrSlc mice as evaluated by ELISA. It also increased the proportion of natural killer (NK) cells and the ratio of CD4(+) to CD8(+) T cells in the spleen from 6.1 ± 0.3 to 7.4 ± 0.5% and from 1.25 ± 0.03 to 1.38 ± 0.04, respectively, compared to the treatment of doxorubicin alone as analyzed by flow cytometry. The mean survival period of melanoma-bearing, doxorubicin treated mice was prolonged from 31.4 ± 7.1 to 35.3 ± 8.4, 51.1 ± 5.4, and 45.0 ± 8.4 days by combinatory treatment of IP-PA1 at the daily doses of 0.1, 0.5, and 1 mg/kg, respectively. In conclusion, the results of the present study suggest the usefulness of IP-PA1 as a supportive drug in melanoma therapy.

Oral administration of lipopolysaccharides for the prevention of various diseases: benefit and usefulness

It is well known that intravenous administration of lipopolysaccharide (LPS) induces severe toxicity in mammals. The maximum tolerated dose of intravenous administration of LPS in humans is reported to be only 1 to 4 ng/kg body weight. However, oral administration of a high dose of LPS caused no toxicity or systemic inflammation in other mammals, birds, or fish. Two weeks of oral administration of a high dose of LPS (2 mg/kg) did not induce toxicity in a rat experiment. Moreover, several experiments have reported that oral administration of LPS had preventative and curative properties against various diseases, including allergic, and lifestyle-related diseases. These results demonstrate that mucosal administration of LPS acts via a different regulatory mechanism in biological responses from that of parenteral administration. Mucosal administration of LPS is thought to be quite promising for prevention of diseases, but LPS is rarely used. In order to expand the usage of oral administration of LPS for preventing lifestyle and allergic diseases, it will be necessary to clarify the mechanisms that arouse immune responses after oral administration of LPS. This short review presents a recent observation of the usefulness of orally administered LPS.

Functional characterization of lipopolysaccharide derived from symbiotic bacteria in rice as a macrophage-activating substance

BACKGROUND AND AIM

Lipopolysaccharide derived from a symbiotic bacterium in wheat (Pantoea agglomerans, LPSp) has shown multiple positive effects, such as prophylactic, antiallergic and antitumour effects, without serious side-effects. LPSp has differential biological activities in comparison to other LPS, such as those from Escherichia coli (LPSe). The only difference between LPSp and LPSe is in the O-antigen polysaccharide structure (O-PS). This led us to the hypothesis that the O-PS structure would seem to participate in biological activities. Thus, the characterization of properties of O-PS in LPS is of the utmost importance for understanding cell activation in the maintenance of homeostasis. However, little is known about the correlation between the O-PS structure of LPS and its biological activities. In this study, we extracted LPS derived from a symbiotic bacterium in rice (strain A46, related species of Pantoea), which has a long history of use in foods, and investigated its putative structures and functions.

MATERIALS AND METHODS

LPS derived from strain A46 was prepared using a hot phenol extraction method. The properties of LPS-A46 were analysed by thin-layer chromatography, Tricine SDS-PAGE and Western blotting. The function of LPS-A46 was analyzed by quantative real-time PCR and flow cytometry using THP-1 cells and Peripheral blood mononuclear cell (PBMC) derived macrophages.

RESULTS

In Tricine SDS-PAGE, high molecular mass LPS-A46 had a molecular mass lower than that of LPSp. In Western blotting, LPS-A46 reacted with lipid A antibody but did not react with an O-PS antibody of LPSp. In comparison to other LPS, LPS-A46 induced a differential cytokine gene expression profile in THP-1 cells and PBMC-derived macrophages.

CONCLUSION

The present study suggests that LPS derived from symbiotic bacterium in rice is a bioactive functional LPS which may have different functional activities compared to other types of LPS.

Antitumor effect of inhalatory lipopolysaccharide and synergetic effect in combination with cyclophosphamide

BACKGROUND

Macrophage cells differentiate into killer macrophages, named M1 macrophages, that effectively eliminate cancer cells by generating cytokines. We examined the feasibility of a lung cancer therapy using lipopolysaccharide (LPS), which triggers this differentiation. It is expected that the delivery via inhalation of LPS directly into the lungs, where alveolar macrophages reside abundantly, would be effective at minimizing the possible toxic effect of LPS.

MATERIALS AND METHODS

We determined the effects of intratracheal insufflation of LPS on (i) the exudation of lactate dehydrogenase, (ii) generation of tumor necrosis factor-α and interleukin-12, and (iii) tumor metastases in Lewis lung carcinoma-bearing C57BL/6 mice.

RESULTS

Pulmonary insufflation of LPS resulted in a consistent accumulation of tumor necrosis factor-α, and transient increase in interleukin-12 without significant release of lactate dehydrogenase from the lung cells. In addition, a significant antitumor effect of LPS was observed; and this antitumor effect was potentiated by combination of LPS with the antitumor agent cyclophosphamide.

CONCLUSION

Pulmonary inhalation of LPS combined with a chemotherapeutic agent is a promising approach to lung cancer therapy.

Recovery from immunosuppression-related disorders in humans and animals by IP-PA1, an edible lipopolysaccharide

Immunopotentiator from Pantoea agglomerans 1 (IP-PA1), an edible lipopolysaccharide (LPS) derived from symbiotic bacteria in crops, is a promising immunomodulator. It activates macrophages and protects from chemotherapeutic agent-induced growth inhibition in macrophages in vitro. We showed the immune-recovery effects of IP-PA1 in a chicken model of dexamethasone-induced stress in which IP-PA1 inhibited thymic and bursal atrophy and improved antibody production in response to vaccination. Furthermore, we showed IP-PA1 improved survival of melanoma-bearing, doxorubicin-treated mice, although not directly affecting the proliferation of melanoma cells, dominantly through the improvement of host antitumor immunity. These results suggest that IP-PA1 could have other possible applications in the treatment of various immunosuppression-related disorders in humans and animals.

Cytotoxic effects of activated alveolar macrophages on lung carcinoma cells via cell-to-cell contact and nitric oxide

AIM

It is possible that macrophages may be effective for cancer treatment because once activated, lung macrophages have enhanced contact with lung tumor cells and have a cytotoxic effect. In this paper, we report that nitric oxide (NO) produced by lung macrophages activated with lipopolysaccharide (LPS) suppressed cell growth of human lung adenocarcinoma cells.

MATERIALS AND METHODS

A549, a lung adenocarcinoma cell line, was cultured with NR8383, a rat alveolar macrophage cell line, in the presence and absence of LPS. The effect of LPS on the growth rate of A549 cells was examined as a function of NO production under cell-to-cell contact conditions.

RESULTS

NR8383 cells showed potent cytostatic and cytocidal effects on A549 cells when both cells were co-cultured in the presence of LPS. These effects were mainly due to the production of NO, but another possible mechanism, such as cell-to-cell contact, may also be involved.

CONCLUSION

Activation of alveolar macrophages by LPS suppresses the growth of lung carcinoma cells via NO production under cell-to-cell contact conditions.

Preparation of lipopolysaccharide derived from Pantoea agglomerans labeled with fluorescence as a tracer for kinetics analysis

BACKGROUND

Intradermal and/or oral administration of lipopolysaccharides derived from Pantoea agglomerans (IP-PA1) have shown multiple positive effects such as phylactic, anti-allergic and anti-tumor effects. It has been reported that the effects of IP-PA1 were derived from the induction of activated macrophages. However, it has not been actually clarified whether or not the orally administered IP-PA1 absorbed in the intestine reached and activated tissue macrophages. The aim of this study was to prepare and evaluate IP-PA1 labeled with fluorescence as a tracer, which could be used for IP-PA1 functional studies (administration, distribution, metabolism and excretion).

MATERIALS AND METHODS

IP-PA1 was labeled with fluorescein isothiocyanate (FITC). IP-PA1 was converted to the monomeric form using triethylamine solvent. Borate buffer (pH 10.5) containing FITC was added to the IP-PA1 solution, and then a sodium deoxycholate solution was added and the mixture incubated for 18 h. The conjugate in the supernatant was dialysed against phosphate-buffered saline and then the purified FITC-IP-PA1 was analyzed on thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) gel filtration. The biological activity of FITC-IP-PA1 was tested with a Limulus assay using a commercial endospecy kit and with a nitric oxide (NO) assay in the RAW 264.7 cell line using Griess reagent. The binding of FITC-IP-PA1 on RAW 264.7 cells was measured by flow cytometry.

RESULTS

FITC-IP-PA1 and free FITC molecules had different Rf values on TLC. The peak of FITC-IP-PA1 and unlabeled IP-PA1 had the same retention time by HPLC. The Limulus activity of FITC-IP-PA1 was 101% compared with unlabeled IP-PA1 (±18.4%). NO production by FITC-IP-PA1 induced dose dependency. In the flow cytometric analysis, RAW 264.7 cells exhibited high fluorescence intensity (99.4%) when cells were incubated with FITC-IP-PA1 (1 μg/ml). The binding of FITC-IP-PA1 to RAW 264.7 cells was inhibited by adding unlabeled IP-PA1.

CONCLUSION

These results demonstrate that both FITC-IP-PA1 and unlabeled IP-PA1 are biologically active. The described FITC-IP-PA1 could be utilized in a variety of IP-PA1 functional studies such as biochemistry, immunohistochemistry, and molecular cell biology.

Lipopolysaccharide-activated alveolar macrophages having cytotoxicity toward lung tumor cells through cell-to-cell binding-dependent mechanism

BACKGROUND

In lung tumor biotherapy, local macrophages such as alveolar macrophages and tumor-associated macrophages (TAMs) which normally exist in contact with tumor cells are thought to be hopeful target. It is advantageous to clarify the potential for and mechanism by which lung tumor cells are killed by the neighboring macrophages in order to establish new lung cancer therapy using a drug delivery system to lung tissue.

MATERIALS AND METHODS

A549, a human lung adenocarcinoma cell line, and Lewis lung carcinoma LLC1, a mouse lung cancer cell line, were co-cultured with NR8383, a rat alveolar macrophage cell line, and AMJ2-C11, a mouse alveolar macrophage cell line, at a ratio of 1:10 and 1:5, respectively. Macrophages were activated with lipopolysaccharide (LPS) and cytotoxicity toward tumor cells was evaluated by a dye-uptake method and (3)H-thymidine release assay, respectively. Nitric oxide (NO) production was estimated by Griess assay, and tumor necrosis factor (TNF)-α and interleukin (IL)-1β were measured by ELISA.

RESULTS

Significant macrophage cell aggregation and cytotoxicity against A549 cells and LLC1 cells was observed with NR8383 cells and AMJ2-C11 cells in the presence of LPS. A high concentration of NO and TNF-α were detected in the supernatant of co-culture medium with LPS. Inhibition of cell-to-cell contact restored A549 cell growth.

CONCLUSION

The LPS-activated alveolar macrophages demonstrated an increased cell-to-cell contact with lung tumor cells and inducing cytotoxicity with production of NO and cytokines TNF-α and IL-1β. These results suggest that moderate activation of local macrophages in lung (alveolar macrophages and TAMs) is thought to be a hopeful means of establishing new immunotherapy for lung cancer.

Protective effects of the immunopotentiator from Pantoea agglomerans 1 on chemotherapeutic agent-induced macrophage growth inhibition

BACKGROUND

The immunopotentiator from Pantoea agglomerans 1 (IP-PA1) is an edible lipopolysaccharide (LPS) derived from symbiotic bacteria found in crops. IP-PA1 is known to ameliorate chemotherapy-induced immunosuppression; therefore, its macrophage-activating effect in the presence of chemotherapeutic agents was evaluated.

MATERIALS AND METHODS

Nuclear factor-kappaB (NF-kappaB) activation in IP-PA1-treated RAW264 and J774.1 cells was examined using Western blot analyses; Griess assay and ELISA were used to examine the production of nitric oxide and tumour necrosis factor alpha, respectively. The expression of apoptosis-related proteins was also assessed using Western blot analyses. The effect of IP-PA1 on doxorubicin-induced apoptosis was analyzed by flow cytometry after annexin-V staining. The growth of macrophages treated with chemotherapeutic agents and IP-PA1 was analyzed using an MTT assay.

RESULTS

IP-PA1 activated NF-kappaB and ameliorated chemotherapy induced growth inhibition in the cells.

CONCLUSION

IP-PA1 is an edible drug that can potentially support chemotherapy by ameliorating chemotherapy-induced immunosuppression.

Two types of tumor necrosis factor-alpha in bluefin tuna (Thunnus orientalis) genes: Molecular cloning and expression profile in response to several immunological stimulants

Tumor necrosis factor-alpha (TNF-alpha) is a key inflammatory mediator and has also the potential as a prominent biomarker of innate immunity. In this study, we identified and characterized TNF-alpha from bluefin tuna, which is an important cultured species. Two types of TNF-alpha were also cloned incidentally (TNF1 and TNF2). The open reading frame of TNF1 and TNF2 cDNA encoded 247 and 245 amino acids, respectively. The amino acid sequence identity among sea perch, red sea bream, and tiger puffer was 73, 70, 59% for TNF1 and 49, 51, 45% for TNF2, respectively. The identity between TNF1 and TNF2 amino acid sequences of the bluefin tuna was only 43%. The positions of cysteine residues, transmembrane sequence, and protease cleavage site in bluefin tuna TNFs were similar with other reported fish and mammalian TNF-alpha. In a phylogenetic analysis, TNF1 is grouped with other reported Perciformes TNF-alpha. On the other hand, TNF2 is grouped with ayu TNF and is quite distant from the fish TNF-alpha group and lymphotoxin-beta group. While TNF1 mRNA showed no significant difference in all tissues, TNF2 mRNA was expressed significantly higher in the blood than in the gill, intestine, head kidney, spleen, heart, and ovary. In peripheral blood leucocytes (PBL), expressions of TNF2 mRNA were significantly increased by stimulation with lipopolysaccharide, phytohemagglutinin, concanavalin A, pokeweed mitogen, phorbol myristate acetate in vitro, but those of TNF1 were not. Recombinant mature TNF1 and TNF2 proteins significantly enhanced phagocytic activity of PBL. Our results suggest that bluefin tuna possess two types of TNF-alpha homologue, and TNF2 is a potential biomarker for innate immunity.

Comparative immunological analysis of innate immunity activation after oral administration of wheat fermented extract to teleost fish

BACKGROUND

Intradermal or oral administration of lipopolysaccharide derived from Pantoea agglomerans (IP-PA1) has shown prophylactic and antitumor effects without serious side-effects. While it is known that tumor necrosis factor (TNF)-alpha produced by activated macrophages plays an important role in the expression mechanism following intradermal administration, details of the mechanism after oral administration remain unclear. In this study, the activation of innate immunity using fish as an animal model was investigated. In fish, the innate immunity system is dominant over acquired immunity.

MATERIALS AND METHODS

Carp (Cyprinus carpio L) were fed IP-PA1 for 7 days. Total RNA was extracted from the head kidney (a major immune organ of teleost fish), and interleukin (IL) - 1beta, IL-6, IL-8, IL-10, IL-12, TNF-alpha and transforming forming growth factor (TGF)-beta mRNAs were quantified by one-step real-time PCR. Phagocytic and bactericidal activity of head kidney leukocytes were estimated using zymosan and Aeromonas hydrophila (a pathogenic bacteria), respectively. Serum lysozyme activity was assayed with Remazol brilliant Blue stained Micrococcus lysodeikticus.

RESULTS

Oral administration of IP-PA1 for 7 days augmented the quantity of mRNA expression of IL-1beta, IL-8, and TNF-alpha mRNA and reduced the expression level of IL-6 mRNA in the head kidney. Phagocytic and bactericidal activity of head kidney leukocytes were significantly enhanced. Moreover, serum lysozyme activities were significantly augmented.

CONCLUSION

The results suggest that oral administration of IP-PA1 induced activation of M1 type macrophages in the immune organ of fish, and this enhanced the function of pathogen elimination. Since the functions of macrophages are highly preserved in comparative immunology, there is a high probability that the preventative or curative effect on various diseases that have been observed in mammals is also related to the activation of macrophages to the M1 type.

Intestinal macrophages involved in the homeostasis of the intestine have the potential for responding to LPS

Recently, there has been interest in the tertiary functions of food, those that maintain human health. Moreover, lipopolysaccharides (LPS), which are components of Gram-negative bacteria, have been found to be highly effective in activating innate immunity and have been rediscovered as new functional food materials. In this review, we discuss the significance of LPS as a food component with reference to these tertiary functions based on recent findings. There is special emphasis on the plasticity of responses to LPS by intestinal macrophages. According to the macrophage-network theory, local macrophages cooperate with other tissue macrophages. For this reason, this review also discusses the possibility that information is transferred throughout the body from intestinal macrophages.

Mechanism for maintaining homeostasis in the immune system of the intestine

Every organism possesses a mechanism for maintaining homeostasis. We have focused on the immune system as a system that helps maintain homeostasis of the body, and particularly on the intestine as the largest organ of immunity in the body. We have also focused our research on the mechanism that responds to foreign substances in the intestine, especially the toll-like receptors (TLR). The activation of myeloid differentiation primary response gene 88 (MyD88) signal transduction as a response to TLR in the intestine is believed to contribute to the maintenance of homeostasis of the body through the homeostasis of the intestine. Furthermore, significant findings were reported in which signal transduction from TLR4 was essential for the maintenance and regulation of the intestine. These results strongly suggest the possibility that homeostasis in the intestine is maintained by TLR4, and signaling by TLR4 after exposure to lipopolysaccharide (LPS) probably has a role in regulating homeostasis. It is expected that the prevention and treatment of various diseases using TLR4 will continue to develop. As LPS is a substance that enhances the activity of TLR4, it will also attract attention as a valuable substance in its own right.

Improvement of allergic dermatitis via regulation of the Th1/Th2 immune system balance by macrophages activated with lipopolysaccharide derived from Pantoea agglomerans (IP-PA1)

Recently, the incidence of allergies has been increasing, especially in advanced countries. The cause of these allergies is believed to be a failure in the immune system balance that has been caused by changes in the living environment. The incidence of allergy shows a negative correlation with the decrease of infectious diseases in childhood. It has been suggested that the key to alleviating allergies is to activate innate immunity by exposure to microbial components such as lipopolysaccharides (LPS). The activation of innate immunity is expected to normalize the T-helper type 1 and 2 (Th1/Th2) immune system balance and to suppress the excessive reaction of Th2 type responses that cause immunoglobulin (Ig) E-dependent allergies. This study introduces information on how the activation of macrophages, which are important in innate immunity, by LPS derived from Pantoea agglomerans (IP-PA1) caused suppressive effects on type I allergic reactions and improved allergic dermatitis. We also summarize our hypothesis that regulating the immune system balance using LPS to stimulate macrophages may be an important procedure for preventing and improving allergic dermatitis.

Utility and safety of LPS-based fermented flour extract as a macrophage activator

The immune system is part of the homeostasis system. Our research is focused on ways to maintain health, with an emphasis on the role of macrophages. We have hypothesized that tissue macrophages form a systemic network which we believe contributes to the homeostasis system, and have named it the 'macrophage network.' This network creates a dynamic equilibrium situation where macrophages control homeostasis. Our research is based on this macrophage network theory as we believe that the innate immune system provides the foundation for the homeostasis system. As part of our research, we have demonstrated that macrophage activation can provide protection and therapeutic effects for various diseases. Therefore, we have also focused on lipopolysaccharide (LPS). We proved that the LPS of Pantoea agglomerans (which we have named IP-PA1) was useful in preventing various health disorders and in restoring health when administered via the oral or transdermal route. We also developed a 'fermented flour extract', which consists largely of IP-PA1. For LPS to become a valuable commodity, it is very important to provide assurance about safety (when administered orally or transdermally) to build confidence. For this reason, we tested fermented flour extract (in which the major component was IP-PA1) to confirm that it was safe. The results of these safety trials confirmed that oral and transdermal administration of fermented flour extract was very safe. Thus, we believe that fermented flour extract is a new substance that will have applications in health food, cosmetics, animal feeds, fisheries feeds and drugs industries.

Intracellular localization of CD14 protein in intestinal macrophages

BACKGROUND

Our research is focused on intestinal macrophages, which are believed to contribute to the maintenance of intestinal homeostasis. In addition, intestinal macrophages are unique in that there is an impairment of expression of tumor necrosis factor (TNF) from lipopolysaccharide (LPS). This characteristic can be attributed to the lack or poor level of expression of toll-like receptor 4 (TLR4) or CD14 on the membrane of intestinal macrophages. We therefore decided to identify where CD14 was localized in intestinal macrophages.

MATERIALS AND METHODS

The endoplasmic reticulum and Golgi apparatus were double stained and the intracellular localization in the intestinal macrophages was observed using a confocal laser microscope.

RESULTS

CD14 of peritoneal macrophages was expressed both in the endoplasmic reticulum and Golgi apparatus. By contrast, intestinal macrophages expressed very little CD14 on the cellular membrane. CD14 was present in the endoplasmic reticulum of intestinal macrophages, but was rare in the Golgi apparatus.

CONCLUSION

The lack of expression of CD14 on the cell membrane of intestinal macrophages may be caused by transport interference from the endoplasmic reticulum to the Golgi apparatus.

ROS and innate immunity

Oxygen is converted into reactive oxygen (RO) by radiation, light, the electron transport system in mitochondria, or by other enzymes and is regulated by the action of antioxidative enzymes which convert RO into an inactive state. Reactive oxygen species (ROS) have a biocidal effect on invading bacteria and they can also injure the cells of the host. For this reason, RO is considered as a general cause of aging and contributes to lifestyle-related diseases and cancer. However, for any organism that uses oxygen as an energy source, RO is inevitably produced and has important biological significance. Apart from the direct activity of RO, recent studies have shown that it functions as a second messenger of signal transduction. In this review, the recent findings related to ROS/nitric oxide (NO) and especially of its relationship to innate immunity are summarized.

The role of toll-like receptor 2 in survival strategies of Mycobacterium tuberculosis in macrophage phagosomes

Mycobacterium tuberculosis (Mtb), an intracellular pathogen, is phagocytosed by alveolar macrophage but it is not digested; it survives, proliferates and establishes Mtb infections. The long-term survival mechanism of Mtb is not yet clear. The host's immune response to Mtb is mainly mediated by a Toll-like receptor 2 (TLR2) in macrophages. In the early stage of the immune response by macrophage activation through TLR2, the proliferation of Mtb is suppressed and there is a direct bactericidal effect or induction of apoptosis in infected macrophages. This indicates that TLR2 signaling functions as a defense system against Mtb infection. However, TLR2 signaling from Mtb also appears to be part of the Mtb strategy to escape immune responses by macrophages, such as has been observed when there has been a decrease in MHC-II expression or antigen-processing activity. TLR signaling is reported both to be and not be involved in the maturation of phagosomes, indicating the possibility of contrary influences. In this review, we summarize immune responses of macrophages through TLR2 in Mtb infection, its involvement in phagosome maturation and we describe survival strategies of Mtb through TLR2 signaling.