Aging Cell最新文献

The aging brain experiences a significant decline in proteasome function. The proteasome is critical for many key neuronal functions including neuronal plasticity, and memory formation/retention. Treatment with proteasome inhibitors impairs these processes. Our study reveals a marked reduction in 20S and 26S proteasome activities in aged mice brains, including in the hippocampus, this is driven by reduced functionality of aged proteasome. The decline in proteasome activity is matched by a decline in 20S proteasome assembly. In contrast, 26S proteasome assembly was found to increase with age, though 26S proteasome activity was still found to decline. Our data suggests that age-related declines in proteasome activity is driven predominantly by reduced functionality of proteasome rather than altered composition. By overexpressing the proteasome subunit PSMB5 in the neurons of mice to increase the proteasome content and thus enhance its functionality, we slowed age-related declines in spatial learning and memory. We then showed acute treatment with a proteasome activator to rescue spatial learning and memory deficits in aged mice. These findings highlight the potential of proteasome augmentation as a therapeutic strategy to mitigate age-related cognitive declines.

Invertebrate models have been instrumental in advancing our understanding of the molecular mechanisms of ageing. The isolation of single gene mutations that both extend lifespan and improve age-related health have identified potential targets for therapeutic intervention to alleviate age-related morbidity. Here, we find that genetic loss of function of the G protein-coupled metabotropic glutamate receptor (DmGluRA) in Drosophila extends the lifespan of female flies. This longevity phenotype was accompanied by lower basal levels of oxidative stress and improved stress tolerance, and differences in early-life behavioural markers. Gene expression changes in DmGluRA mutants identified reduced ribosome biogenesis, a hallmark of longevity, as a key process altered in these animals. We further show that the pro-longevity effects of reduced DmGluRA signalling are dependent on the fly homologue of Fragile X Mental Retardation Protein (FMRP), an important regulator of ribosomal protein translation. Importantly, we can recapitulate lifespan extension using a specific pharmacological inhibitor of mGluR activity. Hence, our study identifies metabotropic glutamate receptors as potential targets for age-related therapeutics.

Dementia, characterized by loss of cognitive abilities in the elderly, poses a significant global health challenge. This study explores the role of astrocytes, one of most representative glial cells in the brain, in mitigating cognitive decline. Specifically, we investigated the impact of Hevin (also known as SPARC-like1/SPARCL-1), a secreted glycoprotein, on cognitive decline in both normal and pathological brain aging. By using adeno-associated viruses, we overexpressed Hevin in hippocampal astrocytes of middle-aged APP/PSEN mice, an established Alzheimer's disease (AD) model. Results demonstrated that Hevin overexpression attenuates cognitive decline, as evidenced by cognitive tests, increased pre- and postsynaptic markers colocalization, and altered expression of synaptic mediators, as revealed by proteomic profiling. Importantly, Hevin overexpression did not influence the deposition of Aβ plaques in the hippocampus, a hallmark of AD pathology. Furthermore, the study extended its findings to middle-aged wild-type animals, revealing improved cognitive performance following astrocytic Hevin overexpression. In conclusion, our results propose astrocytic Hevin as a potential therapeutic target for age-associated cognitive decline.

Retraction: J. Jin, X. Lv, L. Chen, W. Zhang, J. Li, Q. Wang, R. Wang, X. Lu, and D. Miao, "Bmi-1 Plays a Critical Role in Protection From Renal Tubulointerstitial Injury by Maintaining Redox Balance," Aging Cell 13, no. 5 (2014): 797-809, https://doi.org/10.1111/acel.12236. The above article, published online on 11 June 2014, in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal Editor-in-Chief, Monty Montano; The Anatomical Society; and John Wiley & Sons Ltd. The retraction has been agreed upon following an investigation into concerns raised by a third party, which revealed image section duplications between this (Figure 3C, WT TNF-α panel) and another article that was subsequently published by an overlapping group of authors, where the image depicts different experimental details. The investigation discovered further image duplications, showing overlapping fields of view between Figure S3G Cortex and Medulla KO panels and between Figure S4C and S4D Medulla KO TNF-α and IL-6 panels. The explanation and the partial raw data shared by the authors was deemed insufficient to fully address these concerns. Thus, the editors have lost confidence in the presented data and decided to retract the article. The authors disagree with the retraction.

DNA topoisomerases are essential molecular machines that manage DNA topology in the cell and play important roles in DNA replication and transcription. We found that knocking down the enzyme topoisomerase Top2 or its mammalian homolog TOP2B increases the lifespan of S. cerevisiae, C. elegans, and mice. TOP2B reduction also extends the health span of mice and alleviates the pathologies of aging in multiple tissues. At the cellular/molecular level, TOP2B reduction alleviates the major hallmarks of aging, including senescence, DNA damage, and deregulated nutrient sensing. We observed that TOP2B reduction changes the epigenetic landscape of various tissues in old mice toward that of the young animals, and differentially downregulates genes with active promoter and high expression. Our observations suggest that Top2 reduction confers pro-longevity effect across species possibly through a conserved mechanism and may be a promising strategy for longevity intervention.

Inactivation of telomerase (TERT) in adipocyte progenitor cells (APC) expedites telomere attrition, and the onset of diabetes in mice fed high-fat diet (HFD), which promotes APC over-proliferation and replicative senescence. Here, we show that time-restricted feeding or caloric restriction in the postnatal development of mice subsequently subjected to HFD prevents telomere attrition but not glucose intolerance. This metabolic effect of dietary intervention was not observed for mice with TERT KO in endothelial or myeloid cells. To characterize the telomere-independent effects of TERT in the APC lineage, we analyzed mice with TERT knockout in mature adipocytes (AD-TERT-KO), which do not proliferate and avoid telomere attrition. Analysis of adipocytes from AD-TERT-KO mice indicated reliance on glycolysis and decreased mitochondrial oxidative metabolism. We show that AD-TERT-KO mice have reduced cold tolerance and metabolism abnormality indicating a defect in adaptive thermogenesis, characteristic of aging. Conversely, ectopic TERT expression in brown adipocytes-induced mitochondrial oxidation and thermogenic gene expression. We conclude that TERT plays an important non-canonical function in the mitochondria of adipocytes.

Despite the high prevalence of age-dependent intervertebral disc calcification, there is a glaring lack of treatment options for this debilitating pathology. We investigated the efficacy of long-term oral K₃Citrate supplementation in ameliorating disc calcification in LG/J mice, a model of spontaneous age-associated disc calcification. K₃Citrate reduced the incidence of disc calcification without affecting the vertebral bone structure, knee calcification, plasma chemistry, or locomotion in LG/J mice. Notably, a positive effect on grip strength was evident in treated mice. FTIR spectroscopy of the persisting calcified nodules indicated K₃Citrate did not alter the mineral composition. Mechanistically, activation of an endochondral differentiation in the cartilaginous endplates and nucleus pulposus (NP) compartment contributed to LG/J disc calcification. Importantly, K₃Citrate reduced calcification incidence by Ca²⁺ chelation throughout the disc while exhibiting a differential effect on NP and endplate cell differentiation. In the NP compartment, K₃Citrate reduced the NP cell acquisition of a hypertrophic chondrocytic fate, but the pathologic endochondral program was unimpacted in the endplates. Overall, this study for the first time shows the therapeutic potential of oral K₃Citrate as a systemic intervention strategy to ameliorate disc calcification.

Longevity individuals have lower susceptibility to chronic hypoxia, inflammation, oxidative stress, and aging-related diseases. It has long been speculated that "rejuvenation molecules" exist in their blood to promote extended lifespan. We unexpectedly discovered that longevity individuals exhibit erythrocyte oxygen release function similar to young individuals, whereas most elderly show reduced oxygen release capacity. Untargeted erythrocyte metabolomics profiling revealed that longevity individuals are characterized by youth-like metabolic reprogramming and these metabolites effectively differentiate the longevity from the elderly. Quantification analyses led us to identify multiple novel longevity-related metabolites within erythrocytes including adenosine, sphingosine-1-phosphate (S1P), and glutathione (GSH) related amino acids. Mechanistically, we revealed that increased bisphosphoglycerate mutase (BPGM) and reduced MFSD2B protein levels in the erythrocytes of longevity individuals collaboratively work together to induce elevation of intracellular S1P, promote the release of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from membrane to the cytosol, and thereby orchestrate glucose metabolic reprogramming toward Rapoport-Luebering Shunt to induce the 2,3-BPG production and trigger oxygen delivery. Furthermore, increased glutamine and glutamate transporter expression coupled with the enhanced intracellular metabolism underlie the elevated GSH production and the higher anti-oxidative stress capacity in the erythrocytes of longevity individuals. As such, longevity individuals displayed less systemic hypoxia-related metabolites and more antioxidative and anti-inflammatory metabolites in the plasma, thereby healthier clinical outcomes including lower inflammation parameters as well as better glucose-lipid metabolism, and liver and kidney function. Overall, we identified that youthful erythrocyte function and metabolism enable longevity individuals to better counteract peripheral tissue hypoxia, inflammation, and oxidative stress, thus maintaining healthspan.

Increased life expectancy is associated with a higher risk of age-related diseases, which represent a major public health challenge. Animal models play a crucial role in aging research, enabling the study of diseases at the organism level and facilitating drug development and repurposing. Among these models, zebrafish stands out as an excellent in vivo system due to its unique characteristics. However, the longevity of zebrafish is a limitation for research, as it often takes too long to obtain results within a reasonable timeframe. To address this, we have developed a short telomere zebrafish line (ST2) with a premature aging phenotype during the larval stage. Although less extreme than the tert-deficient G2 larvae, ST2 larvae exhibit reduced telomerase expression and activity, along with shortened telomeres. they also exhibit increased cellular senescence, apoptosis, and premature death. As a proof of concept, we evaluated the antiaging effects of two compounds: resveratrol (a polyphenol) and navitoclax (a senolytic). Our results confirm the antiaging properties of resveratrol, which improves telomere maintenance. However, navitoclax does not attenuate the ST2 phenotype. Taking advantage of the zebrafish larval model, this premature aging system provides a valuable platform for in vivo testing of rejuvenating molecules through drug screening, using telomere length or survival as a readout.

The trade-off between reproduction and lifespan has been documented across a wide array of organisms, ranging from invertebrates to mammals. In malnourishing dietary conditions, inhibition of the reproductive processes generally extends the lifespan of females. However, the underlying mechanisms through which nutritional competition driven by reproduction accelerates aging remain poorly understood. Here, using female Drosophila melanogaster as a model, we show that among various dietary conditions lacking specific nutrients, only sterol deficiency significantly exacerbated both the incidence and severity of intestinal barrier deterioration during aging. Sterile mutation specifically ameliorated such damage in sterol-deprived diets, but failed to alleviate age-related intestinal barrier deterioration under other nutritional conditions. Additionally, we demonstrate that the lifespan extension and intestinal barrier amelioration, accompanied by a reproductive suppression effect, through the pharmacological inhibition of mTOR or Ras-Erk signaling using rapamycin or trametinib, were significantly modulated by cholesterol levels. Our study also identifies the morphological changes in excreta as a sensitive biomarker for early intestinal dysfunction. Collectively, these results suggest that the impairment of the intestinal barrier caused by reproductive-induced sterol competition constitutes a significant factor limiting female lifespan in nutritionally unbalanced diets. This work elucidates a salient aspect of the complex interplay between reproductive resource allocation and somatic maintenance, thereby enhancing our understanding of how diet impacts the aging process.