DHA-H and HPA restore impaired neurogenic phenotypes and BDNF-TrkB signaling in Ts65Dn neurospheres and hippocampus

Impaired neurogenesis is a hallmark of neurodevelopmental disorders, including Down syndrome, and contributes to long-lasting deficits in brain structure and function. Membrane lipid composition is emerging as a critical regulator of cell fate decisions in the developing and adult brain. Here we investigate the pro-neurogenic potential of the synthetic PUFA DHA-H (2-hydroxylated DHA) and its immediate metabolite HPA (Heneicosapentaenoic acid) in cellular and tissue models derived from the Ts65Dn mouse model of Down syndrome, using DHA (docosahexaenoic acid) as a reference pro-neurogenic ω-3 PUFA. In primary neurospheres, DHA-H and HPA increased the expression of neural stem and progenitor cell markers, including Sox2, Ki67, and Nestin, and stimulated proliferative activity, accompanied by a parallel upregulation of early neuronal differentiation markers such as Doublecortin and PSA-NCAM. Notably, both compounds promoted the recovery of these markers in Ts65Dn neurospheres, with HPA achieving restoration to wild-type levels for several markers, while DHA-H exerted beneficial effects that varied across the evaluated parameters. These improvements were associated with enhanced BDNF production and TrkB phosphorylation, highlighting the BDNF-TrkB signaling axis as a potential molecular mediator of their pro-neurogenic effects. In vivo, administration of DHA-H and HPA increased BDNF and phospho-TrkB protein levels, together with the number of proliferating cells and mature neurons in the dentate gyrus of the hippocampus, suggesting enhanced activity of the adult neurogenic niche and potential neuroprotective effects. Together, our findings identify DHA-H and HPA as promising modulators of neural progenitor dynamics and neurogenesis in a trisomic context, revealing a lipid-dependent mechanism of neurodevelopmental plasticity and supporting their therapeutic potential for ameliorating impaired neurogenic programs in Down syndrome and related disorders.