Effect Of FUT2 Gene Polymorphism Of Chinese Mothers On The Intestinal Microbiota Of Infants

Objective Human milk oligosaccharides(HMOs)is one of the main components of human milk.The studies showed that Single Nucleotide Polymorphism(SNP)of FUT2 gene can further affect the level of fucosylated HMOs in human milk by modulating the expression level of ? 1,2 fucosyltransferase.In this research,the mothers were divided into secretory and non-secretory mothers according to the level of fucosylated HMOs markes in human milk.We explored the HMOs in human milk of different secretor status of these mothers,figured out the relationship between SNPs of FUT2 gene and secretor status of mothers,furthermore,explored the influence of different secretor status of mothers on intestinal microbiota of infants.Method 56 infant/mother dyads from the second hospital of Da Lian Medical University were selected.The breast milk and infant feces samples were collected at the 6th day and 42 nd day of lactation.The collection and transportation process shall be clean and timely.The total DNA of breast milk samples was extracted,and the SNPs of FUT2 gene were analyzed by polymerase chain reaction(PCR)and sequencing.HMOs was extracted from human breast milk by ethanol precipitation.The HMOs oligosaccharide chain was detected by HPLC-ESI/TOF MS.The total DNA of infant feces was extracted and 16 S r RNA high-throughput sequencing was used to analyze the infant gut microbiota.Result 1.The secretor status of mother is related to SNP of FUT2 gene We tested the secretor status of these mothers by selectively evaluating the abundance of HMOs markers including lactodifucotetraose(LDFT)and lacto-Nfucopentaose I(LNFP I)by Mass spectrometry.Among the mothers,43 were secretory type,accounting for 76.79%,13 were non secretory type,accounting for 23.21%.The rs601338 and rs1047781 SNP sites in FUT2 gene of 56 mothers were PCR and sequenced.The A / T mutation of rs1047781 in FUT2 gene is consistent with the secretor status,that is,in the genome,the a mutation of non-secretor is T.2.The breast milk HMOs was affected by secretor status and day of lactation The abundance of main HMOs in breast milk decreased significantly gradually along with the lactation progress.The level of total HMOs at the 42 nd day was significantly lower than that at the 6th day of lactation(P < 0.0001).The various groups of fucosylated HMOs were significantly reduced,such as 2'-FL modified H2F1,were also significantly reduced(P < 0.05).The richness of fucosylated HMOs in the breast milk of secretor was significantly higher than that of non secretory mothers.At the 6th day,H2F1 and H3N1F2 were significantly higher in secretory mothers' breast milk than in non secretory mothers' breast milk(P < 0.05).At the 42 nd day of lactation,the HMOs 2'-FL,LDFT,LNDFH-I,LNH,MSLNn H was significantly higher than that of non secretory mothers(P < 0.05).3.The composition of gut microbiota of infants is affected by lactation periods There was no statistical difference between the every two groups in the indexes of Chao1,Simpson,Shannon and ACE meaning there was no significant difference in the abundance and diversity of gut microbiota of infants.However,Simpson and Shannon index of gut microbiota were slightly higher in secretor fed infants than in non-secretor fed infants at the 6th day.There was a significant difference of intestinal microbiota composition of the infants between 42 nd day and 6th day(P < 0.05).4.Breastfeeding of secretor mothers increases the abundance of Bifidobacteria in the gut microbiota of infants The results showed that the abundance of Clostridium and Lactobacillus in the of infants in secretor group increased significantly at the 42 th day of the lactation(P < 0.05).For the non-secretor group,at the 42 nd day the abundance of Bifidobacteria was significantly increased,while the abundance of Lachnospira was significantly decreased.The abundance of Bifidobacteria was significantly increased in secretor group.The LEf Se analysis indicated the biomarkers of the 6th daywere Actinobacteria,Bifidobacteria,Bifidobacteria,genus bifidobacteria and Bifidobacterium pseudocatenulatum.By the 42 nd day,the dominated species of secretor group was Bifidobacterium.CCA analysis showed that there was a significant correlation between the HMOs and the intestinal microbiota of breast fed infants(P < 0.05).Spearman's rank analysis showed a significant positive correlation between the Bifidobacteria abundance and the abundance of fucosylated HMOs in breast milk(P < 0.01).The H2F2 of fucosylated HMOs showed that there was a significant positive correlation between the abundance of Bifidobacteria in infant intestine and the level of H2F2(P < 0.01).Conclusion 1.The secretor status of mothers was highly correlated with the A/T mutation of rs1047781,the SNP site in genome of the non-secreted individuals was mutated into T.2.The abundance of main HMOs in breast milk decreased significantly gradually along with the lactation progress.Compared with non-secretory,the abundance of HMOs was higher in secretory mother's milk,especially the fucosylated HMOs.3.The level of HMOs has a significantly positive correlation with the gut Bifidobacteria of infants.