AMPK is a key regulator at the molecular level for maintaining energy metabolism homeostasis. Mammalian AMPK is a heterotrimeric complex, and its catalytic α subunit exists in 2 isoforms: AMPKα1 and AMPKα2. Recent studies suggest a role of AMPKα overactivation in Alzheimer’s disease–associated (AD-associated) synaptic failure. However, whether AD-associated dementia can be improved by targeting AMPK remains unclear, and roles of AMPKα isoforms in AD pathophysiology are not understood. Here, we showed distinct disruption of hippocampal AMPKα isoform expression patterns in postmortem human AD patients and AD model mice. We further investigated the effects of brain- and isoform-specific AMPKα repression on AD pathophysiology. We found that repression of AMPKα1 alleviated cognitive deficits and synaptic failure displayed in 2 separate lines of AD model mice. In contrast, AMPKα2 suppression did not alter AD pathophysiology. Using unbiased mass spectrometry–based proteomics analysis, we identified distinct patterns of protein expression associated with specific AMPKα isoform suppression in AD model mice. Further, AD-associated hyperphosphorylation of eukaryotic elongation factor 2 (eEF2) was blunted with selective AMPKα1 inhibition. Our findings reveal isoform-specific roles of AMPKα in AD pathophysiology, thus providing insights into potential therapeutic strategies for AD and related dementia syndromes.

The supplement telomerase activator TA-65 (purified from Astragalus membranaceus) has been shown to retard cellular senescence, boost the aging immune system, and retard age-related symptoms. Lengthened telomeres retard aging, but because cancers often maintain longevity by lengthening telomeres, dietary telomerase activator might possibly increase tumorigenesis. This study investigated whether oral TA-65 effects the timing of onset and/or the incidence of skin cancers induced by UVB-irradiation and whether that possible effect is different if the oral supplementation is begun only after tumors are first detected clinically or if supplementation is begun before initiation of tumors as well as during and after the inciting UVB exposure. Three groups of ten Skh:1 hairless, nonpigmented mice exposed to UVB for twenty weeks were given (1) no supplementation, (2) TA-65 supplementation starting when the first UV-induced skin cancers were clinically observed, after which the UV exposure was terminated, and (3) TA-65 supplementation before, during, and after UV exposure (as more tumors subsequently appeared). Except for two time points when Group 3 had borderline or statistically more tumors ≥ 2mm per mouse, overall, there was no statistically significant difference in the time of onset, the incidence, or the tumor load of skin cancers with TA-65 with either timing, confirming the safety of this anti-aging supplement in this model of the most frequent human malignancy.