Bacillus amyloliquefaciens Increases the GABA in Rice Seed for Upregulation of Type I Collagen in the Skin

Biosynthesis of gamma-aminobutyric acid (GABA) can be achieved by naturally occurring microorganisms with the advantages of cost-effectiveness and safety. In this study, Bacillus amyloliquefaciens EH-9 strain (B. amyloliquefaciens EH-9), a soil bacterium, was used to promote the accumulation of GABA in germinated rice seed. Further, the topical application of supernatant from rice seed co-cultivated with soil B. amyloliquefaciens EH-9 can significantly increase the production of type I collagen (COL1) in the dorsal skin of mice. The knocking down of the GABA-A receptor (GABA_A) significantly reduced the production of COL1 in the NIH/3T3 cells and in the dorsal skin of mice. This result suggests that topical application of GABA can promote the biosynthesis of COL1 via its interaction with the GABA_A receptor in the dorsal skin of mice. In summary, our findings illustrate for the first time that soil B. amyloliquefaciens EH-9 elicits GABA production in germinated rice seed to upregulate the formation of COL1 in the dorsal skin of mice. This study is translational because the result shows a potential remedy for skin aging by stimulating COL1 synthesis using biosynthetic GABA associated with B. amyloliquefaciens EH-9.