TGFB1 and diabetic kidney disease: These four genera are butyrate-producing bacteria (52–54), and have been reported diversified renoprotective effects for DKD in vivo and in vitro, such as improving intestinal barrier function (55), attenuating fibrosis and collagen deposition, inhibiting inflammation (56), and ameliorating TGF-β1-induced fibrogenesis, apoptosis and DNA damage in the diabetic kidney (57).