HYPOTHALAMIC menin loss drives systemic aging and cognitive decline, whereas restoring expression extends overall animal longevity. In a groundbreaking preclinical investigation, researchers discovered that menin signaling within the ventromedial nucleus of the hypothalamus progressively diminishes over chronological age. This deterioration occurs selectively within steroidogenic factor 1 expressing neurons rather than surrounding astrocytes or microglia. Genetically silencing menin in these hypothalamic circuits induced marked neuroinflammation, disturbed metabolic circadian rhythms, and triggered premature systemic deterioration across multiple organ systems. The resulting physiological decay manifested as reduced bone mineral density, accelerated skin thinning, loss of skeletal muscle mass, and impaired cardiac ventricular architecture.
Beyond peripheral physiological deterioration, selective menin deficiency precipitated pronounced deficits in spatial learning and memory. Mechanistic investigations revealed that hypothalamic menin acts as an essential epigenetic regulator of neuroinflammation and metabolic homeostasis. Specifically, menin binds directly to the promoter region of phosphoglycerate dehydrogenase, the initial rate limiting enzyme in D-serine biosynthesis, through histone H3K4 trimethylation. Aging associated hypothalamic menin reduction suppresses this transcriptional activation, causing a profound deficit in D-serine production. Because steroidogenic factor 1 neurons project directly to the hippocampus, this biosynthetic failure impairs D-serine delivery along the central neural circuit, ultimately attenuating long term potentiation and reducing dendritic spine density in CA1 pyramidal neurons.
Remarkably, viral mediated restoration of hypothalamic menin in the ventromedial hypothalamus of aged mice extended overall lifespan, corrected systemic biomarkers of senescence, and reversed cognitive decline. In parallel experiments, chronic oral administration of D-serine in drinking water successfully rescued hippocampal synaptic plasticity, increased postsynaptic density protein 95 expression, and restored cognitive function without altering peripheral aging markers. Clinical relevance was further underscored by findings that circulating D-serine concentrations are significantly lower in elderly human cohorts compared to young adults. These findings identify hypothalamic menin as a master central pacemaker of systemic aging and suggest that targeting metabolic pathways downstream of hypothalamic menin, such as D-serine replenishment, provides a promising therapeutic strategy to counteract age related neurodegeneration.
Reference
Leng L et al. Hypothalamic Menin regulates systemic aging and cognitive decline. PLoS Biol. 2023;21(3):e3002033.
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