Abstract
Intestinal microbiota plays an important role in human health, and its composition is determined by several factors, such as diet and host genotype. However, thus far it has remained unknown which host genes are determinants for the microbiota composition. We studied the diversity and abundance of dominant bacteria and bifidobacteria from the faecal samples of 71 healthy individuals. In this cohort, 14 were non-secretor individuals and the remainders were secretors. The secretor status is defined by the expression of the ABH and Lewis histo-blood group antigens in the intestinal mucus and other secretions. It is determined by fucosyltransferase 2 enzyme, encoded by the FUT2 gene. Non-functional enzyme resulting from a nonsense mutation in the FUT2 gene leads to the non-secretor phenotype. PCR-DGGE and qPCR methods were applied for the intestinal microbiota analysis. Principal component analysis of bifidobacterial DGGE profiles showed that the samples of non-secretor individuals formed a separate cluster within the secretor samples. Moreover, bifidobacterial diversity (p<0.0001), richness (p<0.0003), and abundance (p<0.05) were significantly reduced in the samples from the non-secretor individuals as compared with those from the secretor individuals. The non-secretor individuals lacked, or were rarely colonized by, several genotypes related to B. bifidum, B. adolescentis and B. catenulatum/pseudocatenulatum. In contrast to bifidobacteria, several bacterial genotypes were more common and the richness (p<0.04) of dominant bacteria as detected by PCR-DGGE was higher in the non-secretor individuals than in the secretor individuals. We showed that the diversity and composition of the human bifidobacterial population is strongly associated with the histo-blood group ABH secretor/non-secretor status, which consequently appears to be one of the host genetic determinants for the composition of the intestinal microbiota. This association can be explained by the difference between the secretor and non-secretor individuals in their expression of ABH and Lewis glycan epitopes in the mucosa.
Highlights
Growing evidence shows that the composition and diversity of the microbiota in the human intestine can have a surprisingly strong impact on the well-being and health of the host
We studied the association of the secretor status with the intestinal microbiota composition by comparing the dominant bacterial and bifidobacterial populations in faecal samples of non-secretor and secretor individuals
These results suggest that the fucosyltransferase 2 (FUT2) gene, which determines the presence of ABH histo-blood group glycans in mucus lining of the intestine, is a host genotypic feature significantly affecting the bacterial composition, the bifidobacterial composition, in the intestine
Summary
Growing evidence shows that the composition and diversity of the microbiota in the human intestine can have a surprisingly strong impact on the well-being and health of the host. The microbiota composition in the human intestinal tract is determined by several factors, such as host genotype, health status, age, microbial interactions, and diet [3]. Growing evidence indicates that host genetic background has a significant impact on the microbiota composition in the intestine, no specific genetic factors determining the intestinal microbiota composition have been established to date. Twin studies applying plate counts, PCR-DGGE fingerprinting or DNA microarrays have shown a higher similarity in the microbiota composition between monozygotic twins than between dizygotic twins, unrelated persons, marital couples and family members [6,7], clearly pointing to a strong effect of host genetics. In the study by Turnbaugh et al [8], the pyrosequencing analysis showed a higher level of similarity in the microbiota composition in twin pairs than between twins and their mothers or unrelated persons, in their study the similarity of the microbiota between monozygotic twins did not differ from that of dizygotic twins
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