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Declining Lamin B1 expression mediates age-dependent decreases of hippocampal stem cell activity

ABSTRACT: Neural stem cells (NSCs) generate neurons throughout life in the hippocampal dentate gyrus (DG). With advancing age levels of neurogenesis sharply drop, which has been associated with a decline in hippocampal memory function. However, cell-intrinsic mechanisms mediating age-related changes in NSC activity remain largely unknown. Here we show that the nuclear lamina protein Lamin B1 (LB1) is downregulated with age in mouse hippocampal NSCs. LB1 is cross-regulated with Sun-domain containing protein 1 (SUN1), previously implicated in Hutchinson-Gilford progeria syndrome (HGPS), a disease of premature aging. LB1 and SUN1 govern the strength of a diffusion barrier in the membrane of the endoplasmic reticulum (ER) that is associated with the segregation of aging factors during NSC divisions. Balancing the levels of LB1 and SUN1 in aged NSCs restores the ER-diffusion barrier. Virus-based restoration of LB1 expression in aged NSCs enhances stem cell activity in vitro and increases progenitor cell proliferation and neurogenesis in vivo. Thus, we here identify a novel mechanism associated with the age-related decline of neurogenesis in the mammalian hippocampus.

ORGANISM(S): Mus musculus

PROVIDER: GSE163795 | GEO | 2020/12/24

REPOSITORIES: GEO

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Project description:Physical exercise stimulates adult hippocampal neurogenesis in mammals, and is considered a relevant strategy for preventing age-related cognitive decline in aging humans. However, its mechanism is controversial. Here, by investigating microRNAs (miRNAs) and their downstream pathways, we uncover that downregulation of miR-135a-5p mediates exercise-induced proliferation of adult NPCs in adult neurogenesis in the mouse hippocampus, likely by activation of phosphatidylinositol (IP3) signaling. Specifically, while overexpression of miR-135 prevents exercise-induced proliferation in the adult mouse hippocampus in vivo and in NPCs in vitro, its inhibition activates NPCs proliferation in resting and aged mice. Label free proteomics and bioinformatics analysis identifies 11 potential targets of miR-135 in NPCs, several of them involved in phosphatidylinositol signaling. Thus, miR-135a is key in mediating exercise-induced adult neurogenesis and opens intriguing perspectives toward the therapeutic exploitation of miR-135 to delay or prevent pathological brain ageing.Physical exercise stimulates adult hippocampal neurogenesis in mammals, and is considered a relevant strategy for preventing age-related cognitive decline in aging humans. However, its mechanism is controversial. Here, by investigating microRNAs (miRNAs) and their downstream pathways, we uncover that downregulation of miR-135a-5p mediates exercise-induced proliferation of adult NPCs in adult neurogenesis in the mouse hippocampus, likely by activation of phosphatidylinositol (IP3) signaling. Specifically, while overexpression of miR-135 prevents exercise-induced proliferation in the adult mouse hippocampus in vivo and in NPCs in vitro, its inhibition activates NPCs proliferation in resting and aged mice. Label free proteomics and bioinformatics analysis identifies 11 potential targets of miR-135 in NPCs, several of them involved in phosphatidylinositol signaling. Thus, miR-135a is key in mediating exercise-induced adult neurogenesis and opens intriguing perspectives toward the therapeutic exploitation of miR-135 to delay or prevent pathological brain ageing.

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Declining Lamin B1 expression mediates age-dependent decreases of hippocampal stem cell activity

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