Knockdown of neuronal DAF-15/Raptor promotes healthy aging in C. elegans.

The highly conserved target of rapamycin (TOR) pathway plays an important role in aging across species. Previous studies have established that inhibition of the TOR complex 1 (TORC1) significantly extends lifespan in Caenorhabditiselegans. However, it has not been clear whether TORC1 perturbation affects aging in a spatiotemporal manner. Here, we apply the auxin-inducible degradation tool to knockdown endogenous DAF-15, the C. elegans ortholog of regulatory associated protein of TOR (Raptor), to characterize its roles in aging. Global or tissue-specific inhibition of DAF-15 during development results in various growth defects, whereas neuron-specific knockdown of DAF-15 during adulthood significantly extends lifespan and healthspan. The neuronal DAF-15 deficiency-induced longevity requires the intestinal activities of DAF-16/FOXO and PHA-4/FOXA transcription factors, as well as the AAK-2/AMP-activated protein kinase α catalytic subunit. Transcriptome profiling reveals that the neuronal DAF-15 knockdown promotes expression of genes involved in protection. These findings define the tissue-specific roles of TORC1 in healthy aging and highlight the importance of neuronal modulation of aging.

ACS-20/FATP4 mediates the anti-ageing effect of dietary restriction in C. elegans.

Dietary restriction is an effective anti-ageing intervention across species. However, the molecular mechanisms from the metabolic aspects of view are still underexplored. Here we show ACS-20 as a key mediator of dietary restriction on healthy ageing from a genetic screen of the C. elegans acyl-CoA synthetase family. ACS-20 functions in the epidermis during development to regulate dietary restriction-induced longevity. Functional transcriptomics studies reveal that elevated expression of PTR-8/Patched is responsible for the proteostasis and lifespan defects of acs-20. Furthermore, the conserved NHR-23 nuclear receptor serves as a transcriptional repressor of ptr-8 and a key regulator of dietary restriction-induced longevity. Mechanistically, a specific region in the ptr-8 promoter plays a key role in mediating the transcription regulation and lifespan extension under dietary restriction. Altogether, these findings identify a highly conserved lipid metabolism enzyme as a key mediator of dietary restriction-induced lifespan and healthspan extension and reveal the downstream transcriptional regulation mechanisms.

Pharmacokinetics, Bioequivalence, and Safety Evaluation of 2 Formulations of 10-mg Rivaroxaban Tablets: A 4-Period Crossover Trial.

This study compared the safety, bioequivalence, and pharmacokinetic properties of 2 formulations of 10-mg rivaroxaban tablets in healthy Chinese participants in fasting and fed arms. The trial was an open, randomized, 4-period, replicated crossover scheme, and 36 volunteers were recruited separately for the fasting and fed arms. Volunteers were randomly administered a single dose of the test or reference formulation (10 mg) orally, followed by a 5-day washout period. Rivaroxaban concentrations in the plasma were determined using liquid chromatography-tandem mass spectrometry, and pharmacokinetic parameters were obtained from the concentration-time profiles. The mean values of the test and the reference product for the area under the plasma concentration-time curve from time 0 to the last measurable concentration, area under the plasma concentration-time curve from time 0 to infinity, and maximum plasma concentration were 996 and 1014 ng • h/mL, 1024 and 1055 ng • h/mL, and 150 and 152 ng/mL in the fasting arm, respectively; the values were 1155 and 1167 ng • h/mL, 1160 and 1172 ng • h/mL, and 202 and 193 ng/mL in the fed arm, respectively. All the parameters were within acceptable limits in terms of bioequivalence. No serious adverse events were observed. This study demonstrated that the 2 rivaroxaban tablets were bioequivalent in healthy Chinese participants under fasting and fed conditions.

Inhibition of PAR-1 delays aging via activating AMPK in C. elegans.

The antagonistic pleiotropy theory of aging suggests that genes essential for growth and development are likely to modulate aging later in life. Previous studies in C. elegans demonstrate that inhibition of certain developmentally essential genes during adulthood leads to significant lifespan extension. PAR-1, a highly conserved serine/threonine kinase, functions as a key cellular polarity regulator during the embryonic development. However, the role of PAR-1 during adulthood remains unknown. Here we show that inhibition of par-1 either by a temperature-sensitive mutant or by RNAi knockdown only during adulthood is sufficient to extend lifespan in C. elegans. Inhibition of par-1 also improves healthspan, as indicated by increased stress resistance, enhanced proteotoxicity resistance, as well as reduced muscular function decline over time. Additionally, tissue-enriched RNAi knockdown analysis reveals that PAR-1 mainly functions in the epidermis to regulate lifespan. Further genetic epistatic and molecular studies demonstrate that the effect of par-1 on lifespan requires the AMP-activated protein kinase (AMPK), and RNAi knockdown of par-1 results in age-dependent AMPK activation and reduced lipid accumulation in the metabolic tissue. Taken together, our findings reveal a previously undescribed function of PAR-1 in adulthood, which will help to understand the molecular links between development and aging.

Translational Regulation of Non-autonomous Mitochondrial Stress Response Promotes Longevity.

Reduced mRNA translation delays aging, but the underlying mechanisms remain underexplored. Mutations in both DAF-2 (IGF-1 receptor) and RSKS-1 (ribosomal S6 kinase/S6K) cause synergistic lifespan extension in C. elegans. To understand the roles of translational regulation in this process, we performed polysomal profiling and identified translationally regulated ribosomal and cytochrome c (CYC-2.1) genes as key mediators of longevity. cyc-2.1 knockdown significantly extends lifespan by activating the intestinal mitochondrial unfolded protein response (UPRmt), mitochondrial fission, and AMP-activated kinase (AMPK). The germline serves as the key tissue for cyc-2.1 to regulate lifespan, and germline-specific cyc-2.1 knockdown non-autonomously activates intestinal UPRmt and AMPK. Furthermore, the RNA-binding protein GLD-1-mediated translational repression of cyc-2.1 in the germline is important for the non-autonomous activation of UPRmt and synergistic longevity of the daf-2 rsks-1 mutant. Altogether, these results illustrate a translationally regulated non-autonomous mitochondrial stress response mechanism in the modulation of lifespan by insulin-like signaling and S6K.

Accelerated Deficits of Spatial Learning and Memory Resulting From Prenatal Inflammatory Insult Are Correlated With Abnormal Phosphorylation and Methylation of Histone 3 in CD-1 Mice.

Gestational infection causes various neurological deficits in offspring, such as age-related spatial learning and memory (SLM) decline. How inflammation causes age-related SLM dysfunction remains unknown. Previous research has indicated that histone modifications, such as phosphorylation of H3S10 (H3S10p) and trimethylation of H3K9 (H3K9me3) may be involved. In our study, pregnant mice received an intraperitoneal injection of lipopolysaccharide (LPS, 50 or 25 µg/kg) or normal saline during gestational days 15-17. After normal parturition, the offspring were randomly separated into 1-, 6-, 12-, 18-, and 22-month-old groups. SLM performance was assessed using a radial six-arm water maze (RAWM). The hippocampal levels of H3S10p and H3K9me3 were detected using an immunohistochemical method. The results indicated that the offspring had significantly impaired SLM, with decreased H3S10p and increased H3K9me3 levels from 12 months onward. Maternal LPS exposure during late gestation significantly and dose-dependently exacerbated the age-related impairment of SLM, with the decrease in H3S10p and increase in H3K9me3 beginning at 12 months in the offspring. The histone modifications (H3S10p and H3K9me3) were significantly correlated with impairment of SLM. Our findings suggest that prenatal exposure to inflammation could exacerbate age-related impairments of SLM and changes in histone modifications in CD-1 mice from 12 months onward, and SLM impairment might be linked to decreased H3S10p and increased H3K9me3.

Construction of a germline-specific RNAi tool in C. elegans.

Analysis of complex biological functions usually requires tissue-specific genetic manipulations in multicellular organisms. The C. elegans germline plays regulatory roles not only in reproduction, but also in metabolism, stress response and ageing. Previous studies have used mutants of rrf-1, which encodes an RNA-directed RNA polymerase, as a germline-specific RNAi tool. However, the rrf-1 mutants showed RNAi activities in somatic tissues. Here we constructed a germline-specific RNAi strain by combining an indel mutation of rde-1, which encodes an Argonaute protein that functions cell autonomously to ensure RNAi efficiency, and a single copy rde-1 transgene driven by the sun-1 germline-specific promoter. The germline RNAi efficiency and specificity are confirmed by RNAi phenocopy of known mutations, knockdown of GFP reporter expression, as well as quantitative RT-PCR measurement of tissue-specific mRNAs upon RNAi knockdown. The germline-specific RNAi strain shows no obvious deficiencies in reproduction, lipid accumulation, thermo-tolerance and life span compared to wild-type animals. By screening an RNAi sub-library of phosphatase genes, we identified novel regulators of thermo-tolerance. Together, we have created a useful tool that can facilitate the genetic analysis of germline-specific functions in C. elegans.