Supplementation with ubiquinol 10 has been shown to improve the health of experimental animals and elderly individuals. The present study investigated the effects of lifetime supplementation with ubiquinol 10 on the progression of aging and lifespan in C57BL/6 mice, a standard strain for biomedical and aging research. A diet containing ubiquinol 10 (0.3 % w/w) and a control diet were fed to female C57BL/6J mice from 8 weeks of age until death, and the progression of senescence, lifespan, and physiological and pathological findings were examined. Body weights increased until 72 weeks of age and then decreased gradually in both groups. Food intake was significantly higher in the ubiquinol 10 group until 56 weeks of age. The median, 10th decile (10 % survivors), and maximum lifespans and survival curves did not significantly differ between the ubiquinol 10 and control groups. The grading score of senescence improved only at the age of 48 weeks in ubiquinol 10 group. No significant differences were observed in major physiological markers, such as the glucose tolerance test, serum triglycerides, and cholesterol concentrations. The expression levels of genes regulating aging in the liver markedly decreased with age in both groups. Organ weights did not significantly differ, except for significantly lighter brown adipose tissue in the ubiquinol 10 group. Senile AApoAII amyloidosis was noted in old mice; however, the degree of amyloid deposition was similar in the two groups. The degree of senescence only improved in middle-aged mice (48 weeks of age), and no apparent anti-aging or lifespan-extending effects were observed with lifetime supplementation with ubiquinol 10 in female C57BL/6J mice, which are standard laboratory mice considered to exhibit normal aging processes.

The co-deposition of amyloid fibrils from different precursor proteins is a topic of increasing relevance for protein misfolding diseases. Using cryo-electron microscopy (cryo-EM), we here determined the structures of two serum amyloid A (SAA) protein-derived amyloid fibril morphologies that were extracted from a mouse strain that is primarily known to be associated with apolipoprotein A-II-derived amyloid fibrils. The two fibril morphologies show the same protomer conformation as in previously reported ex vivo amyloid fibrils from SAA protein but a different relative arrangement of fibril protein stacks. These data establish that serum amyloid A-derived amyloid fibrils share the same fibril protein fold in different mouse strains and disease contexts.

Amyloid resistance is the inability or the reduced susceptibility of an organism to develop amyloidosis. In this study we have analysed the molecular basis of the resistance to systemic AApoAII amyloidosis, which arises from the formation of amyloid fibrils from apolipoprotein A-II (ApoA-II). The disease affects humans and animals, including SAMR1C mice that express the C allele of ApoA-II protein, whereas other mouse strains are resistant to development of amyloidosis due to the expression of other ApoA-II alleles, such as ApoA-IIF. Using cryo-electron microscopy, molecular dynamics simulations and other methods, we have determined the structures of pathogenic AApoAII amyloid fibrils from SAMR1C mice and analysed the structural effects of ApoA-IIF-specific mutational changes. Our data show that these changes render ApoA-IIF incompatible with the specific fibril morphologies, with which ApoA-II protein can become pathogenic in vivo.

Amyloidosis refers to a group of degenerative diseases that are characterized by the deposition of misfolded protein fibrils in various organs. Deposited amyloid may be removed by a phagocyte-dependent innate immune system; however, the precise mechanisms during disease progression remain unclear. We herein investigated the properties of macrophages that contribute to amyloid degradation and disease progression using inducible apolipoprotein A-II amyloidosis model mice. Intravenously injected AApoAII amyloid was efficiently engulfed by reticuloendothelial macrophages in the liver and spleen and disappeared by 24 h. While cultured murine macrophages degraded AApoAII via the endosomal-lysosomal pathway, AApoAII fibrils reduced cell viability and phagocytic capacity. Furthermore, the depletion of reticuloendothelial macrophages before the induction of AApoAII markedly increased hepatic and splenic AApoAII deposition. These results highlight the physiological role of reticuloendothelial macrophages in the early stages of pathogenesis and suggest the maintenance of phagocytic integrity as a therapeutic strategy to inhibit disease progression.

Exercise interventions are beneficial for reducing the risk of age-related diseases, including amyloidosis, but the underlying molecular links remain unclear. Here, we investigated the protective role of interval exercise training in a mouse model of age-related systemic apolipoprotein A-II amyloidosis (AApoAII) and identified potential mechanisms. Mice subjected to 16 weeks of exercise showed improved whole-body physiologic functions and exhibited substantial inhibition of amyloidosis, particularly in the liver and spleen. Exercise activated the hepatic p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway and the downstream transcription factor tumor suppressor p53. This activation resulted in elevated expression and phosphorylation of heat shock protein beta-1 (HSPB1), a chaperone that defends against protein aggregation. In amyloidosis-induced mice, the hepatic p38 MAPK-related adaptive responses were additively enhanced by exercise. We observed that with exercise, greater amounts of phosphorylated HSPB1 accumulated at amyloid deposition areas, which we suspect inhibits amyloid fibril formation. Collectively, our findings demonstrate the exercise-activated specific chaperone prevention of amyloidosis, and suggest that exercise may amplify intracellular stress-related protective adaptation pathways against age-associated disorders, such as amyloidosis.