Repressed Wnt Signaling Accelerates the Aging Process in Mouse Eyes

Defective Mitochondrial Dynamics Underlie Manganese-Induced Neurotoxicity

Perturbations in mitochondrial dynamics have been observed in most neurodegenerative diseases. Here, we focus on manganese (Mn)-induced Parkinsonism-like neurodegeneration, a disorder associated with the preferential of Mn in the basal ganglia where the mitochondria are considered an early target. Despite the extensive characterization of the clinical presentation of manganism, the mechanism by which Mn mediated mitochondrial toxicity is unclear. In this study we hypothesized whether Mn exposure alters mitochondrial activity, including axonal transport of mitochondria and mitochondrial dynamics, morphology, and network. Using primary neuron cultures exposed to 100 μM Mn (which is considered the threshold of Mn toxicity in vitro) and intraperitoneal injections of MnCl2 (25mg/kg) in rat, we observed that Mn increased mitochondrial fission mediated by phosphorylation of dynamin-related protein-1 at serine 616 (p-s616-DRP1) and decreased mitochondrial fusion proteins (MFN1 and MFN2) leading to mitochondrial fragmentation, defects in mitochondrial respiratory capacity, and mitochondrial ultrastructural damage in vivo and in vitro. Furthermore, Mn exposure impaired mitochondrial trafficking by decreasing dynactin (DCTN1) and kinesin-1 (KIF5B) motor proteins and increasing destabilization of the cytoskeleton at protein and gene levels. In addition, mitochondrial communication may also be altered by Mn exposure, increasing the length of nanotunnels to reach out distal mitochondria. These findings revealed an unrecognized role of Mn in dysregulation of mitochondrial dynamics providing a potential explanation of early hallmarks of the disorder, as well as a possible common pathway with neurological disorders arising upon chronic Mn exposure.

Axin-Mediated Regulation of Lifespan and Muscle Health in C. elegans Requires AMPK-FOXO Signaling

Aging is a significant risk factor for several diseases. Studies have uncovered multiple signaling pathways that modulate aging, including insulin/insulin-like growth factor-1 signaling (IIS). In Caenorhabditis elegans, the key regulator of IIS is DAF-16/FOXO. One of the kinases that affects DAF-16 function is the AMPK catalytic subunit homolog AAK-2. In this study, we report that PRY-1/Axin plays an essential role in AAK-2 and DAF-16-mediated regulation of life span. The pry-1 mutant transcriptome contains many genes associated with aging and muscle function. Consistent with this, pry-1 is strongly expressed in muscles, and muscle-specific overexpression of pry-1 extends life span, delays muscle aging, and improves mitochondrial morphology in AAK-2-DAF-16-dependent manner. Furthermore, PRY-1 is necessary for AAK-2 phosphorylation. Taken together, our data demonstrate that PRY-1 functions in muscles to promote the life span of animals. This study establishes Axin as a major regulator of muscle health and aging.

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pry-1 transcriptome contains genes linked to aging and muscle function

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pry-1 functions in muscles to maintain life span and mitochondrial network

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Muscle-specific overexpression of pry-1 extends life span and promotes muscle health

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PRY-1-mediated life span extension depends on AAK-2-DAF-16 signaling