Folate and Vitamin B12 Gestational Deficiency Disturb Glucocorticoid Response in Hypothalamus Through N-Homocysteinilation of the Glucocorticoid Receptor

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Vitamin B9(folate)/B12 deficiency is known to induce brain structural and/or functional retardations. Besides neural tube defects in case of major consequences, several mild deregulations also lead to deleterious effect after birth, and folate supplementation recommended in some countries usually stop at the end of the first trimester. Various hormonal receptors were shown to be deregulated in brain tissue under this context. The glucocorticoid receptor (GR) is particularly sensitive to epigenetic regulation and post-traductional modifications. In a mother-offspring rat model of vitamin B9/B12 deficiency, we investigated whether a prolonged folate supplementation could restore the GR signalization in the hypothalamus. Our data showed that a deficiency in folate and vitamin B12 during the in-utero and the early postnatal periods was associated with reduced GR expression inn the hypothalamus. We also described for the first time a new post-traductional modification of GR that impaired ligand binding and GR activation, leading to decreased the expression of one of the GR targets in the hypothalamus, AgRP. Moreover, this brain-impaired GR pathway was associated with behavioral perturbations during offspring growth. Importantly, perinatal and postnatal supplementation with folic acid helped restore GR mRNA level and activity in hypothalamus cells and improved behavioral deficits.

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