Kanehisa Morimoto

Association between genetic variants of mast-cell chymase and eczema

BACKGROUND Atopy is a common syndrome underlying asthma, rhinitis, and eczema, and is characterised by high immunoglobulin E (IgE) responses to common antigens. IgE and mast-cell chymase (MCC-a serine protease secreted by skin mast cells) have a key role in atopic or allergic inflammation of the skin. The gene for MCC is located within a cluster of genes for cellular proteases on chromosome 14q11.2. We aimed to identify variants of MCC and another gene within this complex, and assess whether there is a genetic association between variants of MCC and atopic disorders-particularly eczema. METHODS We randomly selected 100 controls and recruited patients-100 in each group-with atopic asthma, non-atopic asthma, atopic rhinitis, and atopic eczema. PCR amplification was used to test genomic DNA for an association between allelic polymorphisms in MCC and a flanking gene (CGL1, for the cathepsin-G-like protein) on chromosome 14q11 and asthma, rhinitis, and eczema. FINDINGS We found a significant association between a BstXI polymorphism in MCC and eczema (odds ratio 2.17 [95% CI 1.21-3.88], p = 0.009), but no association with atopic asthma, rhinitis, or non-atopic asthma. There was no association between an Mboll polymorphism in CGL1 and any of the atopic disorders. INTERPRETATION These findings suggest that variants of MCC may be one source of genetic risk for eczema.

Characterization of the three genotypes of low Km aldehyde dehydrogenase in a Japanese population.

A deficiency in low Km aldehyde dehydrogenase (ALDH2) is regarded as the main factor responsible for “Oriental flushing” and other symptoms due to alcohol sensitivity. In this study, the relationship of the ALDH2 genotype to alcohol-associated symptoms and drinking behavior was investigated in 524 Japanese workers, using a new, rapid, and nonisotopic polymerase chain reaction (PCR) method. Differences in the frequency of alcohol-associated manifestations between the normal homozygote and the other deficient types were apparent. In addition, among the ALDH2-deficient individuals, the atypical homozygote was obviously more hypersensitive to alcohol than the heterozygote, judging from the frequency of flushing or other drinking-associated manifestations with a small dose of alcohol. Drinking frequency also apparently decreased in the following order: typical homozygote, heterozygote, atypical homozygote. Similarly, mean amounts of alcohol consumption also decreased in the same order, although considerable variation existed within the typical homozygote and the heterozygote group. In contrast, neither the manifestations nor the drinking behavior were, in general, influenced by polymorphism of the alcohol dehydrogenase β-subunit (ADH2) gene in males. These findings further indicate the important contribution of the ALDH2 genotype to alcohol sensitivity in Orientals.

Healthy lifestyles are associated with higher natural killer cell activity

BACKGROUND To investigate the association of individual lifestyle with immune response against tumors, we assayed peripheral blood lymphocytes of 62 healthy males ranging in age from 30 to 60 years for natural killer (NK) cell activity, which is the first line of defense against tumors, and for frequencies of NK cell subsets. METHODS The NK cell activity was determined by 51Cr release assay, and NK cell subsets were counted using surface antigens (CD16, CD57) which recognize NK cell subgroups with different cytolytic potentials. Subjects were classified into groups reporting good, moderate, and poor lifestyles according to their responses on a questionnaire regarding eight health practices (tobacco smoking, alcohol consumption, hours of sleep, physical exercise, eating breakfast, balanced nutrition, hours of work habits, and mental stress). RESULTS Individuals reporting good lifestyle habits were found to have the highest NK cell activity and it was significantly higher than the NK cell activity in those reporting poor lifestyle habits. Those reporting good health practices regarding smoking and physical exercise showed significantly higher NK cell activity at an effector-to-target-cell ratio of 40:1. CONCLUSIONS The higher NK cell activity among individuals reporting good lifestyle practices may reflect an increase in the cytolytic potential of NK cell activity within the CD16+, CD57- subset.

Linkage between severe atopy and chromosome 11q13 in Japanese families

Atopy, characterised by allergic asthma and rhinitis, is due to increased IgE responses to common aeroallergens. An Oxford group has described maternal inheritance of atopy, where there is significant linkage between IgE responsiveness and a VNTR marker D11S97 and a CA microsatellite within a candidate gene, the high affinity IgE receptor β subunit(FcεRIβ), on chromosome 11q. Attempts at independent replication have produced conflicting results. We therefore recruited 270 atopic asthmatic probands in a Japanese community population for genetic linkage analysis. Four families, each with more than 15 meioses and a clear phenotype for atopy, were selected for genetic analysis. Atopy was defined as presence of all of raised total IgE, positive RAST and skin tests to three or more aeroallergens; non‐atopy, as absence of all these criteria. Linkage analysis showed a maximum two‐point lod score of 9.35 for D11S97 and FcεRIβ under the assumption of unequal rates of maternal and paternal recombination. Two families showed close genetic linkage with FcεRIβ with a pattern of maternal inheritance. These results from a Japanese population provide further evidence for genetic linkage between severe atopy and chromosome 11q13 and the likelihood of genomic imprinting at the locus.

The contribution of polymorphism in the alcohol dehydrogenase β subunit to alcohol sensitivity in a Japanese population

In humans, ingested alcohol is mainly metabolized by the combination of class I alcohol dehydrogenase (ADII) and aldehyde dehydrogenase (ALDH). In Orientals, there are highly frequent polymorphisms both in the class I ADH β subunit (ADHZ) and in the low Km ALDH (ALDH2). We characterized the three genotypes of ALDH2 in a Japanese population. In the present study, we evaluated the effects of the ADH2 polymorphism in the same population (424 males and 100 females) controlling for the effects of the ALDH2 polymorphism. In the ALDH21/ALDH22 group, the frequency of facial flushing with one glass of beer was significantly higher in the ADH21/ADH22 and ADH22/ADH22 genotype than in the ADH21/ADH21 genotype. Likewise, the proportion of persons with positive results for ethanol-induced cutaneous erythema differed significantly depending on the ADH2 genotype in both the ALDH21/ALDH21 and ALDH21/ALDH22 genotypes. However, drinking habits were not significantly associated with the ADH2 genotype, suggesting that the ADH2 genotype influences the metabolism of ethanol only in the peripheral tissues.

Genotype difference of aldehyde dehydrogenase 2 gene in alcohol drinkers influences the incidence of Japanese colorectal cancer patients.

A case‐control study was conducted to explore the possible etiologic role of alcohol and aldehyde dehydrogenase 2 (ALDH2) gene among Japanese colorectal cancer patients. Information on their drinking, smoking and dietary habits was collected from 265 colon and 164 rectum cancer patients, and 794 non‐cancer patients as a control group. Genotypes of the ALDH2 gene at codon 487, glutamic acid (ALDH2*1)as a wild‐type or lysine (ALDH2*2)as a mutated type with reduced enzyme activity, were analyzed by polymerase chain reaction in 160 colon and 110 rectum cancer patients and 121 control persons. Univariate analysis with the χ2 statistical test showed that heavy alcohol drinking (P < 0.01), frequent meat intake (P < 0.001), and irregular (P < 0.01), hasty (P < 0.01) and excessive (P <0.001) eating habits were associated with the incidence of both colon and rectum cancers, whereas heavier smoking (P < 0.05) and infrequent fish (P < 0.03)and fruit (P < 0.01) intake were solely associated with incidence of rectum cancer. Infrequent green vegetable intake was not correlated with the incidence of colorectal cancer. Multivariate unconditional logistic regression analysis confirmed the association of alcohol consumption (P < 0.01) and meat intake (P < 0.05). Homozygous and heterozygous carriers of ALDH2*2 allele tended to be found in colon (trend P= 0.04)but not in rectum cancer patients compared to controls. Risk elevation for colon cancer due to alcohol consumption was pronounced among the heterozygotes and it was statistically significant especially for distal colon cancer (trend P=0.02). We conclude that alcohol consumption is a risk factor for colorectal cancer and the risk can be enhanced in ALDH2 heterozygotes.

Forest bathing enhances human natural killer activity and expression of anti-cancer proteins.

In order to explore the effect of forest bathing on human immune function, we investigated natural killer (NK) activity; the number of NK cells, and perforin, granzymes and granulysin-expression in peripheral blood lymphocytes (PBL) during a visit to forest fields. Twelve healthy male subjects, age 37–55 years, were selected with informed consent from three large companies in Tokyo, Japan. The subjects experienced a three-day/two-night trip in three different forest fields. On the first day, subjects walked for two hours in the afternoon in a forest field; and on the second day, they walked for two hours in the morning and afternoon, respectively, in two different forest fields. Blood was sampled on the second and third days, and NK activity; proportions of NK, T cells, granulysin, perforin, and granzymes A/B-expressing cells in PBL were measured. Similar measurements were made before the trip on a normal working day as the control. Almost all of the subjects (11/12) showed higher NK activity after the trip (about 50% increased) compared with before. There are significant differences both before and after the trip and between days 1 and 2 in NK activity. The forest bathing trip also significantly increased the numbers of NK, perforin, granulysin, and granzymes A/B-expressing cells. Taken together, these findings indicate that a forest bathing trip can increase NK activity, and that this effect at least partially mediated by increasing the number of NK cells and by the induction of intracellular anti-cancer proteins.

Phytoncides (Wood Essential Oils) Induce Human Natural Killer Cell Activity

To explore the effect of forest bathing on the human immune system, we investigated the effect of phytoncides (wood essential oils) on natural killer (NK) activity and the expression of perforin, granzyme A and granulysin in human NK cells. We used NK-92MI cell, an interleukin-2 independent human NK cell line derived from the NK-92 cell, in the present study. NK-92MI cells express the CD56 surface marker, perforin, granzyme A, and granulysin by flow cytometry and are highly cytotoxic to K562 cells in chromium release assay. Phytoncides significantly increase cytolytic activity of NK-92MI cells in a dose-dependent manner and significantly increase the expression of perforin, granzyme A, and granulysin in the NK-92MI cells. Phytoncides also partially, but significantly, restore the decreased human NK activity and the decreased perforin, granzyme A, and granulysin expression in NK-92MI cells induced by dimethyl 2,2-dichlorovinyl phosphate (DDVP), an organophosphorus pesticide. Pretreatment with phytoncides partially prevents DDVP-induced inhibition of NK activity. Taken together, these data indicate that phytoncides significantly enhance human NK activity and this effect is at least partially mediated by induction of intracellular perforin, granzyme A, and granulysin.

A comparison of the 8-hydroxydeoxyguanosine, chromosome aberrations and micronucleus techniques for the assessment of the genotoxicity of mercury compounds in human blood lymphocytes

We compared the mechanism of action of micronuclei (MN), unstable chromosome aberrations, and 8-hydroxydeoxyguanosine (8-OHdG) levels to evaluate the genotoxicity of methyl mercuric chloride (CH3HgCl) and mercuric chloride (HgCl2) in human peripheral lymphocytes. The chromosome aberrations in human peripheral lymphocytes exposed to various concentrations of CH3HgCl or HgCl2 increased in a concentration-dependent manner and were significantly higher than the control when the cells were incubated with 1 x 10(-5) M (HgCl2) or 2 x 10(-6) M (CH3HgCl). The increase in the incidence of micronucleated lymphocytes was significant among the exposed groups, being 2 x 10(-5) M (HgCl2) and 5 x 10(-6) M (CH3HgCl) compared with the control. CH3HgCl was about 4-fold more potent than HgCl2. We determined the 8-OHdG levels in human peripheral blood mononuclear cells(PBMC) and found that they were significantly higher in the exposed groups at 1 x 10(-5) M (HgCl2) and 5 x 10(-6) M (CH3HgCl) compared with the control. A detectable (p < 0.05) increase in the level of 8-OHdG was induced by CH3HgCl at a concentration that was about 50% of the amount of HgCl2 required to produce a similar response. The data confirmed the value of the MN and/or chromosome aberration assays for assessing of HgCl2- and/or CH3HgCl-induced genotoxicity, and indicated that they are about the same concentration as the 8-OHdG assay. The presence of genotoxic effects in peripheral blood lymphocytes exposed to the mercuric compounds indicated by the chromosome aberrations and the MN assays could be partly due either to the disturbance of the spindle mechanism, or to the elevated level of 8-OHdG brought by the generation of reactive oxygen species.

Secretory IgA in Saliva can be a Useful Stress Marker

To evaluate secretory immunoglobulin A (slgA) in saliva as an immunological stress marker, we reviewed the literature on slgA and its variation caused by psychosocial factors. Among the studies on the effect of academic stress on slgA secretion, we could distinguish two kinds of stress effects: the immediate stress effect which increases slgA secretion immediately after stress, and the delayed stress effect which decreases slgA secretion several days after stress. On the basis of production and secretion mechanisms of slgA, we also speculated on possible mechanisms that underlie the variations of slgA caused by stress. Eventually, we concluded diat slgA in saliva can be a useful stress marker if we analyze the delayed stress effect on slgA separately from the immediate stress effect on slgA.