Table 1 Effectors of postnatal feeding regulating FoxP3 ⁺ Treg differentiation

Amount of protein influx (Excessive by formula feeding)

Protein and amino acids regulate the magnitude of AKT- and mTORC1-activity that controls the expression of FoxP3.

Exosomal microRNA (Absent in artificial formula)

Exosomal microRNA-155 enhances the expression of FoxP3, which promotes microRNA-155 expression.

Bifidobacteria (Absent in artificial formula)

Breast milk delivers bifidobacteria and milk-derived oligosaccharides that promote bacterial growth in the gut. Bifidobacteria induce intestinal generation of FoxP3⁺ iTregs.

Polyunsaturated fatty acids (Not adequately provided by formula feeding)

n-3-Polyunsaturated fatty acids inhibit mTORC1 activation, thus promote FoxP3 expression, whereas saturated fatty acids activate mTORC1, thus attenuate FoxP3 expression.