Caloric restriction has been shown to robustly ameliorate age-related diseases and to prolong lifespan in several model organisms, and these beneficial effects are dependent on the stimulation of autophagy. Autophagy dysfunction contributes to the accumulation of altered macromolecules, and is a key mechanism of promoting aging and age-related disorders, as neurodegenerative ones. We have previously shown that caloric restriction (CR), and CR mimetics Neuropeptide Y (NPY) and ghrelin, stimulate autophagy in rat cortical neurons, however by unknown molecular mechanisms. Overall, we show that CR, NPY, and ghrelin stimulate autophagy through PI3K/AKT/MTOR inhibition and ERK1/2-MAPK activation. The knowledge of these kinases in autophagy regulation and the contribution to the understanding of molecular mechanism facilitates the discovery of more targeted therapeutic strategies to stimulate autophagy, which is relevant in the context of age-related disorders.
Hutchinson-Gilford progeria syndrome (HGPS) is a rare and fatal genetic condition arising from a single nucleotide alteration in the LMNA gene, which leads to the production of a defective lamin A protein known as progerin. The buildup of progerin hastens the onset of premature and expedited aging. Patients with HGPS exhibit short stature, low body weight, lipodystrophy, metabolic dysfunction, and skin and musculoskeletal abnormalities and, in most cases, die of cardiovascular disease by their early teenage years. Currently, no effective cure or treatment for the disease highlights the importance of discovering new therapeutic strategies. Herein, we present evidence that the hormone ghrelin, besides promoting autophagy and progerin clearance, rescued several cellular hallmarks of premature aging of human HGPS fibroblasts. Using an HGPS mouse model, LmnaG609G/G609G mice, we also show that ghrelin administration rescued the short-lived mice molecular and histopathological progeroid features, prevented progressive weight loss at later stages, reverted the lipodystrophic phenotype, and extended lifespan. Thus, we disclose that modulation of ghrelin signaling may give rise to new treatment targets and translational approaches that may improve outcomes and the health quality of HGPS patients and natural aging pathologies.
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