Stimulation of IFN-γ production by garlic lectin in mouse spleen cells: involvement of IL-12 via activation of p38 MAPK and ERK in macrophages.

Several lectins, present in beans and edible plant products, have immuno-potentiating and anti-tumor activities. We here report the effects of garlic lectin purified from garlic bulbs on the production of cytokines such as interleukin-12 (IL-12) and interferon-γ (IFN-γ) in the mouse. Garlic lectin induced IFN-γ production in spleen cells in a bell-shaped time (24-60 h)- and concentration (0.25-2.0 mg/ml)-dependent manner. The maximal enhancement was observed at 36 h with 0.5 mg/ml of garlic lectin. The stimulatory effect of garlic lectin on IFN-γ production was completely inhibited by both actinomycin D and cycloheximide, an inhibitor of ribosomal protein synthesis and DNA-dependent RNA polymerase, respectively, and was associated with an increase in IFN-γ mRNA level. Garlic lectin also induced IL-12 production in mouse peritoneal macrophages in a concentration (0.25-1.0 mg/ml)- and bell-shaped time (3-24 h)-dependent manner. The lectin increased the phosphorylation of extracellular signal-regulated kinases (ERK) and p38 mitogen-activated protein kinase (p38 MAPK) in macrophages. Furthermore, specific pharmacological inhibitors of ERK kinase (U0126) and p38 MAPK (SB203580) also suppressed the production of IL-12 induced by garlic lectin. The present findings suggest that garlic lectin induces IL-12 production via activation of p38 MAPK and ERK in mouse macrophages, which, in turn, stimulates IFN-γ production through an increase in IFN-γ mRNA in the spleen cells.

Purification, characterization and biological activities of a garlic oligosaccharide.

A novel oligosaccharide was purified from garlic (Allium sativum L.) bulbs via hot water extraction, ammonium sulfate precipitation, gel filtration and ion exchange chromatography. The molecular weight of the oligosaccharide was determined to be 1800. A nuclear magnetic resonance (NMR) study showed that ten fructose molecules were connected by beta1-2 linkage to a terminal glucose. The oligosaccharide had cytotoxic activities against human malignant lymphoma cells (U937) and colon adenocarcinoma cells (WiDr) in vitro. Furthermore, this oligosaccharide significantly suppressed the growth of murine colon adenocarcinoma cells (colon 26) in vivo. The oligosaccharide also stimulated interferon-gamma production by human peripheral blood lymphocyte in vitro, indicating that it may activate the immunological pathways and suppress the growth of tumors in vivo.

The difference of mutation in the peroxisome proliferator activated receptor gamma2 gene among people at high altitudes and low altitudes in Bolivia.

Peroxisome proliferator activated receptor (PPAR) gamma is present in two isoforms generated by alternative splicing, PPAR gamma 1 and PPAR gamma 2. A Pro12Ala polymorphism in human PPAR gamma 2 moderately reduces its transcriptional activity, and thus PPAR gamma 2 is thought to be a promising candidate gene for several human disorders, including obesity and type 2 diabetes mellitus. In this report, we examined the polymorphism of the PPAR gamma 2 gene in people at high and low altitudes in Bolivia, and found a significant difference in the frequency of Ala carriers (Pro/Ala and Ala/Ala) between 153 native high-altitude Bolivian subjects (64.1%) and 288 low-altitude Bolivian subjects (37.9%). The frequency of this Ala allele in Bolivian subjects was fairly higher than that in other ethnic groups. As body mass index, however, was not associated with Pro12Ala polymorphism of the PPAR gamma 2 gene among either the high altitude Bolivians or low altitude Bolivians, Pro12Ala polymorphism of the gene has little relationship to obesity in Bolivians.

Polymorphism of Trp64Arg in beta3-adrenergic receptor gene among Bolivian people in rural areas at high and low altitudes.

BACKGROUND: To investigate whether population differences in food and/or lifestyle could affect the distribution frequencies of polymorphism in the gene for beta3-adrenergic receptor (beta3-AR), the frequency of Trp64Arg polymorphism was studied among Bolivian people living in rural areas of high (about 4000 m above sea level) and low (about 300 m above sea level) altitudes. METHODS: Genomic DNA samples of Bolivian subjects (n=508) were amplified by polymerase chain reaction (PCR) for part of the beta3-AR gene. The amplified PCR products were digested with restriction enzyme NciI and analysed by agarose gel electrophoresis. RESULTS: We found no significant difference in the frequency of Arg allele in the beta3-AR gene between 331 native low-altitude Bolivian subjects (18.1%) and 177 native high-altitude Bolivian subjects (17.5%). Body mass index was not associated with Trp64Arg polymorphism among native Bolivian adults. The frequency of this allele in the complete Bolivian population (18%) was lower than that reported in Pima Indians (32%), is comparable to the Japanese (19%) and is higher than several ethnic groups, including Finns (12%) and French (4%). CONCLUSIONS: Our data indicate that the altitude-related lifestyle of a population has had little influence on the frequency of Trp64Arg polymorphism and obesity in Bolivian natives.

Down-regulation of telomerase activity by anticancer drugs in human ovarian cancer cells.

Maintenance of telomere length is crucial for survival of cells. Telomerase, an enzyme that is responsible for elongation of shortened telomeres, is active in human germ cells as well as most tumor tissues and experimentally immortalized cells. In contrast, most mature somatic cells in human tissues express undetectable or low telomerase activity, implying the existence of a stringent and negative regulatory mechanism. In this study we report the effects of anticancer drugs on telomerase activity in human cancer cells. In assaying for telomerase activity, we basically followed the original TRAP assay system, but with some modifications. A down-regulation of telomerase activity was found when cells of a human ovarian cancer cell line, A2780, were treated with;cis-diamminedichloroplatinum(II) (CDDP; cisplatin). However, down-regulation of telomerase activity was not found in cells of a cisplatin-resistant cell line, A2780CP, treated with cisplatin. On the other hand, telomerase activity in both the cell lines A2780 and A2780CP was reduced when A2780 or A2780CP was treated with adriamycin, an anthracycline antibiotic having a broad spectrum of antineoplastic activity. The different effects on the telomerase activity of the two types of anticancer drugs may be due the distinct chemical functions of these drugs. The present results may indicate a positive relationship between anticancer effects and down-regulation of telomerase activity by anticancer drugs.