Hydroxycitrate delays early mortality in mice and promotes muscle regeneration while inducing a rich hepatic energetic status.

ATP citrate lyase (ACLY) inhibitors have the potential of modulating central processes in protein, carbohydrate, and lipid metabolism, which can have relevant physiological consequences in aging and age-related diseases. Here, we show that hepatic phospho-active ACLY correlates with overweight and Model for End-stage Liver Disease score in humans. Wild-type mice treated chronically with the ACLY inhibitor potassium hydroxycitrate exhibited delayed early mortality. In AML12 hepatocyte cultures, the ACLY inhibitors potassium hydroxycitrate, SB-204990, and bempedoic acid fostered lipid accumulation, which was also observed in the liver of healthy-fed mice treated with potassium hydroxycitrate. Analysis of soleus tissue indicated that potassium hydroxycitrate produced the modulation of wound healing processes. In vivo, potassium hydroxycitrate modulated locomotor function toward increased wire hang performance and reduced rotarod performance in healthy-fed mice, and improved locomotion in mice exposed to cardiotoxin-induced muscle atrophy. Our findings implicate ACLY and ACLY inhibitors in different aspects of aging and muscle regeneration.

Impaired Plakophilin-2 in obesity breaks cell cycle dynamics to breed adipocyte senescence.

Plakophilin-2 (PKP2) is a key component of desmosomes, which, when defective, is known to promote the fibro-fatty infiltration of heart muscle. Less attention has been given to its role in adipose tissue. We report here that levels of PKP2 steadily increase during fat cell differentiation, and are compromised if adipocytes are exposed to a pro-inflammatory milieu. Accordingly, expression of PKP2 in subcutaneous adipose tissue diminishes in patients with obesity, and normalizes upon mild-to-intense weight loss. We further show defective PKP2 in adipocytes to break cell cycle dynamics and yield premature senescence, a key rheostat for stress-induced adipose tissue dysfunction. Conversely, restoring PKP2 in inflamed adipocytes rewires E2F signaling towards the re-activation of cell cycle and decreased senescence. Our findings connect the expression of PKP2 in fat cells to the physiopathology of obesity, as well as uncover a previously unknown defect in cell cycle and adipocyte senescence due to impaired PKP2.

Molecular motor protein KIF5C mediates structural plasticity and long-term memory by constraining local translation.

Synaptic structural plasticity, key to long-term memory storage, requires translation of localized RNAs delivered by long-distance transport from the neuronal cell body. Mechanisms and regulation of this system remain elusive. Here, we explore the roles of KIF5C and KIF3A, two members of kinesin superfamily of molecular motors (Kifs), and find that loss of function of either kinesin decreases dendritic arborization and spine density whereas gain of function of KIF5C enhances it. KIF5C function is a rate-determining component of local translation and is associated with ∼650 RNAs, including EIF3G, a regulator of translation initiation, and plasticity-associated RNAs. Loss of function of KIF5C in dorsal hippocampal CA1 neurons constrains both spatial and contextual fear memory, whereas gain of function specifically enhances spatial memory and extinction of contextual fear. KIF5C-mediated long-distance transport of local translation substrates proves a key mechanism underlying structural plasticity and memory.