Aging Cell最新文献

Due to the increased burden of non-AIDS-related comorbidities in people living with HIV (PLHIV), identifying biomarkers and mechanisms underlying premature aging and the risk of developing age-related comorbidities is a priority. Evidence suggests that the plasma proteome is an accurate source for measuring biological age and predicting age-related clinical outcomes. To investigate whether PLHIV on antiretroviral therapy (ART) exhibit a premature aging phenotype, we profiled the plasma proteome of two independent cohorts of virally suppressed PLHIV (200HIV and 2000HIV) and one cohort of people without HIV (200FG) using O-link technology. Next, we built a biological age-prediction model and correlated age advancement (the deviation of the predicted age from the chronological age) with HIV-related factors, comorbidities, and cytokines secreted by immune cells. We identified a common signature of 77 proteins associated with chronological age across all cohorts, most of which were involved in inflammatory and senescence-related processes. PLHIV showed increased age advancement compared to people without HIV. In addition, age advancement in the 2000HIV cohort was positively associated with prior hepatitis C and cytomegalovirus (CMV) infections, non-AIDS-related comorbidities, ART duration, cumulative exposure to the protease inhibitor Ritonavir, as well as higher production of monocyte-derived proinflammatory cytokines and chemokines and lower secretion of T-cell derived cytokines. Our proteome-based predictive model is a promising approach for calculating the age advancement in PLHIV. This will potentially allow for further characterization of the pathophysiological mechanisms linked to accelerated aging and enable monitoring the effectiveness of novel therapies aimed at reducing age-related diseases in PLHIV.

Multimodal study of Alzheimer's disease (AD) dorsolateral prefrontal cortex (DLPFC) showed AD-related aberrant intron retention (IR) and proteomic changes not observed at the RNA level. However, the role of sex and how IR may impact the proteome are unclear. Analysis of DLPFC transcriptome showed a clear sex-biased pattern where female AD had 1645 elevated IR events compared to 80 in male AD DLPFC. Increased IR is correlated with lower mRNA levels, suggestive of nonsense-mediated mRNA decay. Two hundred thirty-three mRNAs with elevated IR in females were curated AD genes enriched for ubiquitin-like protein ligase and Tau protein binding. Increased IR genes in combined sex and female AD cohorts showed significant changes in their protein expression patterns with 11%-24% of them differential expressed proteins (DEP), alluding to the regulation of AD proteome by IR independent of RNA level. Upregulated DEPs in male AD were linked to RNA splicing that may prevent aberrant IR, whereas in female AD, they overlapped significantly more with the MAPK/metabolism module associated with cognitive decline. IR genes appeared to be significantly downregulated in specific female AD inhibitory and excitatory neurons compared to control. Differentially retained introns in female AD have elevated H3K27ac marks, strong CTCF binding at their flanking exons, and enriched for PABPC1 motif. Given that H3K27ac is repressive over gene bodies in aged brain and CTCF impedes transcription elongation, their binding patterns can delay co-transcriptional recruitment of spliceosome to cause IR, which may in turn contribute to different trajectories of AD pathology in women.

The decline of oocyte quality with advanced maternal age has a detrimental effect on female fertility. However, there is limited knowledge of therapeutic options and their mechanisms to improve oocyte quality in reproductively older women. In this study, we demonstrated that supplementation of salidroside improves the oocyte quality of reproductively old mice. Salidroside improved the maturation, fertilization, and developmental competence of oocytes from reproductively old mice by maintaining the normal spindle/chromosome structure and mitochondrial function. Oocyte transcriptomic and micro-proteomic analysis revealed that salidroside restores oocyte quality by enhancing mitophagy in reproductively old mice. Our studies provide a new theoretical foundation for utilizing salidroside to improve oocyte quality in reproductively old females in the context of natural fertility or assisted reproduction.

The current mechanism by which aging reduces salivary secretion is unknown. This study investigates the mechanism of aging-related submandibular (SMG) dysfunction and evaluates the therapeutic potential of dental pulp stem cell-derived exosomes (DPSC-exos). We found that the stimulated salivary flow rate was significantly reduced in naturally aging and D-galactose-induced aging mice (D-gal mice) compared to control mice. Acinar atrophy and periductal fibrosis in SMGs and parotid glands (PGs) were observed in naturally aging and D-gal mice, whereas sublingual glands (SLGs) had no notable alterations. We observed the accumulation of senescent cells in the SMGs, along with a decrease in claudin-3 (Cldn-3) expression and alterations in the distribution of Cldn1 and Cldn3. Additionally, after D-gal-induced senescence of SMG-C6 cells, there was a decrease in paracellular pathway permeability, reduced expression of Cldn3 and occludin, and changes in the distribution of Cldn1, 3, 4, and 7. Furthermore, injecting DPSC-exos into the SMGs of D-gal mice improved stimulated salivary flow rate, reduced acinar atrophy, and decreased SA-β-gal activity. Our study identified that increased senescence of SMGs in aging mice can cause a decrease in salivary secretion by disrupting the expression and distribution of tight junction molecules, and injection of DPSC-exos ameliorates SMG secretory dysfunction. These findings may provide new clues to novel therapeutic targets for aging-related dysfunction of SMGs.

Epigenetic clocks are a common group of tools used to measure biological aging-the progressive deterioration of cells, tissues, and organs. Epigenetic clocks have been trained almost exclusively using blood-based tissues, but there is growing interest in estimating epigenetic age using less-invasive oral-based tissues (i.e., buccal or saliva) in both research and commercial settings. However, differentiated cell types across body tissues exhibit unique DNA methylation landscapes and age-related alterations to the DNA methylome. Applying epigenetic clocks derived from blood-based tissues to estimate epigenetic age of oral-based tissues may introduce biases. We tested the within-person comparability of common epigenetic clocks across five tissue types: buccal epithelial, saliva, dry blood spots, buffy coat (i.e., leukocytes), and peripheral blood mononuclear cells. We tested 284 distinct tissue samples from 83 individuals aged 9-70 years. Overall, there were significant within-person differences in epigenetic clock estimates from oral-based versus blood-based tissues, with average differences of almost 30 years observed in some age clocks. In addition, most epigenetic clock estimates of blood-based tissues exhibited low correlation with estimates from oral-based tissues despite controlling for cellular proportions and other technical factors. Notably, the Skin and Blood clock exhibited the greatest concordance across all tissue types, indicating its unique ability to estimate chronological age in oral- and blood-based tissues. Our findings indicate that application of blood-derived epigenetic clocks in oral-based tissues may not yield comparable estimates of epigenetic age, highlighting the need for careful consideration of tissue type when estimating epigenetic age.

Streptococcus pneumoniae (Sp; pneumococcus), the most common agent of community-acquired pneumonia, can spread systemically, particularly in the elderly, highlighting the need for adjunctive therapies. The airway epithelial barrier defends against bacteremia and is dependent upon apical junctional complex (AJC) proteins such as E-cadherin. After mouse lung challenge, pneumolysin (PLY), a key Sp virulence factor, stimulates epithelial secretion of an inflammatory eicosanoid, triggering the infiltration of polymorphonuclear leukocytes (PMNs) that secrete high levels of neutrophil elastase (NE), thus promoting epithelial damage and systemic infection. Here, pulmonary E-cadherin staining of intratracheally (i.t.) inoculated mice revealed PLY-mediated disruption of AJC independently of PMNs. Apical infection of air-liquid interface (ALI) respiratory epithelial monolayers similarly showed that PLY disrupts AJCs. This epithelial damage promoted PMN transmigration and bacterial apical-to-basolateral translocation, and pharmacologically fortifying epithelial barrier function diminished both barrier breach in vitro and bacteremia in vivo. E-cadherin staining after Sp i.t. inoculation of > 20-month-old mice, or apical infection of ALI monolayers derived from these mice, revealed an age-associated vulnerability to PLY-mediated AJC disruption, which in turn enhanced PMN migration and bacteremia. In addition, we found that PMNs from aged mice secrete increased levels of tissue-damaging NE. Simultaneous pharmacological inhibition of tissue-destructive NE and fortification of pulmonary epithelial barrier function was required to reduce the level of Sp bacteremia in aged mice to that of young mice. This work underscores the importance of fully characterizing the multifactorial sources of age-associated susceptibility in devising adjunctive therapies to mitigate invasive pneumococcal disease in the elderly.

Integrating dietary interventions have been extensively studied for their health benefits, such as Alzheimer's disease, Huntington's disease, and aging. However, it is necessary to fully understand the mechanisms of long-term effects and practical applications of these dietary interventions for health. A 10-week intermittent fasting (IMF) regimen was implemented on the aging animals in the current study. The variations of cerebral functions were analyzed employing a comprehensive experimental design that includes behavioral tests, neuroimaging, and ultrastructural analysis, such as resting-state functional MRI (rsfMRI), EEG/EMG recordings, transmission electron microscopy, and immunohistochemistry. Over a 10-week regimen, IMF significantly improved locomotor activity, motor coordination, and muscle strength compared to controls (p < 0.01). Resting-state fMRI (rsfMRI) demonstrated that IMF modulates brain-wide functional connectivity, enhancing communication between key brain regions. Advanced imaging techniques revealed increased expression of myelin-related proteins, including myelin basic protein (MBP), and myelin-associated glycoprotein (MAG), indicating enhanced myelin integrity and repair, particularly in axons with diameters < 400 nm (p < 0.01). These findings suggest that IMF may mitigate age-related declines by promoting better neuronal signaling. This study highlights the potential function of IMF as a non-pharmacological intervention to promote brain health and mitigate cognitive decline in aging populations.

Cinnamon, renowned for its aromatic flavor, represents one of the most widely used spices worldwide. Cinnamon is also considered beneficial to human health with therapeutic potential for treating various diseases, ranging from diabetes and cancer to neurodegenerative diseases. However, the mechanisms underlying cinnamon's health benefits remain elusive. It is also unclear whether cinnamon has any role in aging. Using C. elegans as a model, here we show that feeding worms cinnamaldehyde (CA), the active ingredient in cinnamon oil, prolongs longevity. CA also promotes stress resistance and reduces β-Amyloid toxicity in a C. elegans model of Alzheimer's disease. Mechanistically, CA exerts its beneficial effects through mTORC1 and autophagy signaling. Interestingly, CA promotes longevity by inducing a dietary restriction-like state without affecting food intake, suggesting CA as a dietary restriction mimetic. In human cells, CA exerts a similar effect on mTORC1 and autophagy signaling, suggesting a conserved mechanism. Our results demonstrate that dietary cinnamon promotes both lifespan and healthspan and does so by regulating mTORC1 and autophagy signaling.

Accumulation of damaged biomolecules in body tissues is the primary cause of aging and age-related chronic diseases. Since this damage often occurs spontaneously, it has traditionally been regarded as untreatable, with typical therapeutic strategies targeting genes or enzymes being ineffective in this domain. In this report, we demonstrate that an antibody targeting the isoDGR damage motif in lung tissue can guide immune clearance of harmful damaged proteins in vivo, effectively reducing age-linked lung inflammation. We observed age-dependent accumulation of the isoDGR motif in human lung tissues, as well as an 8-fold increase in isoDGR-damaged proteins in lung fibrotic tissues compared with healthy tissue. This increase was accompanied by marked infiltration of CD68+/CD11b + macrophages, consistent with a role for isoDGR in promoting chronic inflammation. We therefore assessed isoDGR function in mice that were either naturally aged or lacked the isoDGR repair enzyme. IsoDGR-protein accumulation in mouse lung tissue was strongly correlated with chronic inflammation, pulmonary edema, and hypoxemia. This accumulation also induced mitochondrial and ribosomal dysfunction, in addition to features of cellular senescence, thereby contributing to progressive lung damage over time. Importantly, treatment with anti-isoDGR antibody was able to reduce these molecular features of disease and significantly reduced lung pathology in vivo.

Understanding the complex biological process of aging is of great value, especially as it can help develop therapeutics to prolong healthy life. Predicting biological age from gene expression data has shown to be an effective means to quantify aging of a subject, and to identify molecular and cellular biomarkers of aging. A typical approach for estimating biological age, adopted by almost all existing aging clocks, is to train machine learning models only on healthy subjects, but to infer on both healthy and unhealthy subjects. However, the inherent bias in this approach results in inaccurate biological age as shown in this study. Moreover, almost all existing transcriptome-based aging clocks were built around an inefficient procedure of gene selection followed by conventional machine learning models such as elastic nets, linear discriminant analysis etc. To address these limitations, we proposed DeepQA, a unified aging clock based on mixture of experts. Unlike existing methods, DeepQA is equipped with a specially designed Hinge-Mean-Absolute-Error (Hinge-MAE) loss so that it can train on both healthy and unhealthy subjects of multiple cohorts to reduce the bias of inferring biological age of unhealthy subjects. Our experiments showed that DeepQA significantly outperformed existing methods for biological age estimation on both healthy and unhealthy subjects. In addition, our method avoids the inefficient exhaustive search of genes, and provides a novel means to identify genes activated in aging prediction, alternative to such as differential gene expression analysis.