Abstract
Intergenerational stress increases lifetime susceptibility to depression and other psychiatric disorders. Whether intergenerational stress transmission is a consequence of in utero neurodevelopmental disruptions vs early-life mother-infant interaction is largely unknown. Here, we demonstrated that exposure to traumatic stress in mice during pregnancy, through predator scent exposure, induces in the offspring social deficits and depressive-like behavior. We found, through cross-fostering experiments, that raising of normal pups by traumatized mothers produced a similar behavioral phenotype to that induced in pups raised by their biological traumatized mothers. Good caregiving (by non-traumatized mothers), however, did not completely protect against the prenatal trauma-induced behavioral deficits. These findings support a two-hit stress mechanism of both in utero and early-life parenting (poor caregiving by the traumatized mothers) environments. Associated with the behavioral deficits, we found profound changes in brain metabolomics and transcriptomic (metabotranscriptome). Striking increases in the mitochondrial hypoxia marker and epigenetic modifier 2-hydroxyglutaric acid, in the brains of neonatal and adult pups whose mothers were exposed to stress during pregnancy, indicated mitochondrial metabolism dysfunctions and epigenetic mechanisms. Bioinformatic analyses revealed mechanisms involving stress- and hypoxia-response metabolic pathways in the brains of the neonatal mice, which appear to lead to long-lasting alterations in mitochondrial-energy metabolism, and epigenetic processes pertaining to DNA and chromatin modifications. Most strikingly, we demonstrated that an early pharmacological intervention that can correct mitochondria metabolism - lipid metabolism and epigenetic modifications with acetyl-L-carnitine (ALCAR) supplementation - produces long-lasting protection against the behavioral deficits associated with intergenerational transmission of traumatic stress.
Competing Interest Statement
The authors have declared no competing interest.
