Table 1.

Effectors of postnatal feeding regulating FoxP3 ⁺ Treg differentiation

Effectors	Mechanisms of FoxP3-induction
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.