The effect of LAO1 in breast milk on the pup's microbiome formation.

L-Amino Acid Oxidase 1 (LAO1) serves as an enzyme catalyzing the conversion of L-amino acids into alpha-keto acids, ammonia, and hydrogen peroxide. Prior research has indicated that offspring nourished with milk from LAO1 knockout (KO) dams exhibit distinct differences in their gut microbiome composition when compared to both wild-type (WT) and LAO1 KO mice. LAO1 KO mice also display impairments in hippocampal memory function. The primary objective of this study is to elucidate how alterations in the gut microbiome induced by LAO1 KO dam's milk may impact the brain development of their offspring. To account for the potential influence of endogenous LAO1, foster mothers were replaced on the day the pups were born, with the mother mice being either of the WT or LAO1 KO, while the pups themselves were LAO1 KO. At the age of 10 days, cecal fecal samples were collected and subsequently transplanted into germ-free (GF) mice. Two and six weeks after transplantation into GF mice, the GF mice were sacrificed, and we found GF mice inoculated with offspring nourished with milk from LAO1 KO mother show abnormal hippocampal gene expression. These GF mice cecal feces were collected for 16S-rRNA gene sequencing to confirm composition and functional alteration.