Sitagliptin Extends Lifespan of Caenorhabditis elegans by Inhibiting Insulin/Insulin-Like Signaling and Activating Dietary Restriction-Like Signaling Pathways.

INTRODUCTION: The discovery of longevity molecules that delay aging and prolong lifespan has always been a dream of humanity. Sitagliptin phosphate (SIT), an oral dipeptidyl peptidase-4 (DPP-4) inhibitor, is an oral drug commonly used in the treatment of type 2 diabetes (T2D). In addition to being antidiabetic, previous studies have reported that SIT has shown potential to improve health. However, whether SIT plays a role in the amelioration of aging and the underlying molecular mechanism remain undetermined. METHODS: Caenorhabditis elegans (C. elegans) was used as a model of aging. Lifespan assays were performed with adult-stage worms on nematode growth medium plates containing FUdR with or without the specific concentration of SIT. The period of fast body movement, body bending rates, and pharyngeal pumping rates were recorded to assess the healthspan of C. elegans. Gene expression was confirmed by GFP fluorescence signal of transgenic worms and qPCR. In addition, the intracellular reactive oxygen species levels were measured using a free radical sensor H2DCF-DA. RESULTS: We found that SIT significantly extended lifespan and healthspan of C. elegans. Mechanistically, we found that several age-related pathways and genes were involved in SIT-induced lifespan extension. The transcription factors DAF-16/FOXO, SKN-1/NRF2, and HSF-1 played important roles in SIT-induced longevity. Moreover, our findings illustrated that SIT-induced survival benefits by inhibiting the insulin/insulin-like signaling pathway and activating the dietary restriction-related and mitochondrial function-related signaling pathways. CONCLUSION: Our work may provide a theoretical basis for the development of anti-T2D drugs as antiaging drugs, especially for the treatment of age-related disease in diabetic patients.

Effects of Tung Oil Composite Regenerating Agent on Rheological Properties and Microstructures of Reclaimed Asphalt Binder.

The single light oil regenerating agent has certain limitations on the performance recovery of aged asphalt. In this study, tung oil, dioctyl phthalate (DOP), C9 petroleum resin, and organic montmorillonite (OMMT) were used to prepare the composite regenerating agent, and its optimal mix proportion was determined by the orthogonal experimental design. The rheological properties and anti-aging performance of reclaimed asphalt were studied by the dynamic shear rheometer (DSR) and bending beam rheometer (BBR); and the Fourier transform infrared (FTIR) spectrometer, gel permeation chromatography (GPC), and scanning electron microscope (SEM) were adopted to explore its microstructure, morphology, and mechanism of action. The results show that with the addition of tung oil composite regenerating agent, the rheological properties of aged asphalt can be effectively recovered, even better than that of base asphalt. By using the complex modulus aging index (CMAI) and phase angle aging index (PMAI) it is found that the anti-aging performance of reclaimed asphalt is better than that of base asphalt. With the optimal content of the tung oil composite regenerating agent, the contents of characteristic functional groups and macromolecular asphaltenes in the aged asphalt can be reduced, indicating that the composite regenerating agent is beneficial to the dispersion and dissolution of polar substances in the aged asphalt. After aging, a large number of wrinkles appear on the surface of the asphalt. However, the addition of the tung oil composite regenerating agent can make the asphalt surface smooth, which indicates that the tung oil composite regenerating agent can restore the microstructure and morphology of aged asphalt to a certain extent.

Gene activation in Caenorhabditis elegans using the Campylobacter jejuni CRISPR-Cas9 feeding system.

Clustered regularly interspaced palindromic repeats-based activation system, a powerful genetic manipulation technology, can modulate endogenous gene transcription in various organisms through fusing nuclease-deficient Cas9 to transcriptional regulatory domains. At present, this clustered regularly interspaced palindromic repeats-based activation system has been applied to activate gene expression by microinjection manner in Caenorhabditis elegans. However, this complicated and time-consuming injection manner is not suitable for efficient and high-throughput gene regulation with clustered regularly interspaced palindromic repeats-Cas9 system. Here, we engineered a Campylobacter jejun clustered regularly interspaced palindromic repeats-Cas9-based gene activation system through bacteria feeding technique to delivering gene-specific sgRNA in C. elegans. It enables to activate various endogenous genes efficiently, as well as induce the corresponding phenotypes with a more efficient and labor-saving manner. Collectively, our results demonstrated that our novel dCjCas9-based activation feeding system holds great promise and potential in C. elegans.

Histone H3K4me3 modification is a transgenerational epigenetic signal for lipid metabolism in Caenorhabditis elegans.

As a major risk factor to human health, obesity presents a massive burden to people and society. Interestingly, the obese status of parents can cause progeny's lipid accumulation through epigenetic inheritance in multiple species. To date, many questions remain as to how lipid accumulation leads to signals that are transmitted across generations. In this study, we establish a nematode model of C. elegans raised on a high-fat diet (HFD) that leads to measurable lipid accumulation, which can transmit the lipid accumulation signal to their multigenerational progeny. Using this model, we find that transcription factors DAF-16/FOXO and SBP-1/SREBP, nuclear receptors NHR-49 and NHR-80, and delta-9 desaturases (fat-5, fat-6, and fat-7) are required for transgenerational lipid accumulation. Additionally, histone H3K4 trimethylation (H3K4me3) marks lipid metabolism genes and increases their transcription response to multigenerational obesogenic effects. In summary, this study establishes an interaction between a network of lipid metabolic genes and chromatin modifications, which work together to achieve transgenerational epigenetic inheritance of obesogenic effects.

N6-methyldeoxyadenine and histone methylation mediate transgenerational survival advantages induced by hormetic heat stress.

Environmental stress can induce survival advantages that are passed down to multiple generations, representing an evolutionarily advantageous adaptation at the species level. Using the nematode worm Caenorhabditis elegans as a model, we found that heat shock experienced in either parent could increase the longevity of themselves and up to the fifth generation of descendants. Mechanistic analyses revealed that transcription factor DAF-16/FOXO, heat shock factor HSF-1, and nuclear receptor DAF-12/FXR functioned transgenerationally to implement the hormetic stress response. Histone H3K9me3 methyltransferases SET-25 and SET-32 and DNA N6-methyl methyltransferase DAMT-1 participated in transmitting high-temperature memory across generations. H3K9me3 and N6-methyladenine could mark heat stress response genes and promote their transcription in progeny to extend life span. We dissected the mechanisms responsible for implementing and transmitting environmental memories in descendants from heat-shocked parents and demonstrated that hormetic stress caused survival benefits could be transmitted to multiple generations through H3K9me3 and N6-mA modifications.

Research on the Rheological Characteristics and Aging Resistance of Asphalt Modified with Tourmaline.

Tourmaline modified asphalt (TMA) binders were prepared with different modifier types and contents in this research. The routine properties, rheological properties, and aging resistance were evaluated to research the function of tourmaline on the performances of asphalt binders. Test results show that the storage stability can be improved significantly by the smaller particle size and negative-ion treated surface of tourmaline modifier. It indicates that the stiffness and rutting-resistance of TMA binder can be enhanced significantly, and the elastic component of the viscoelastic characteristic can also be increased. Moreover, the complex viscosity and the Zero Shear Viscosity (ZSV) values of tourmaline modified asphalt are increased within the test frequency range, which results in the improvement of deformation resistance of tourmaline modified asphalt. When mixed with asphalt, the tourmaline modifier maintains a two-phase structure, which results in the good rheological property for tourmaline modified asphalt.

Performance Degradation of Large-Sized Asphalt Mixture Specimen under Heavy Load and its Affecting Factors Using Multifunctional Pavement Material Tester.

With the increase of heavy traffic transportation, it is meaningful to study the performance change of pavements under heavy loads. To study the development of asphalt mixture under heavy load, an AC-13 asphalt mixture was prepared and a large-sized specimen wheel tracking test was conducted. Samples from different periods were extracted to research the influence of the cumulative load times under heavy load on asphalt mixtures. It was found that there were different variation rules on the performance of the asphalt mixture under different load conditions. The failure time on skid resistance was predicted by the fitting curve. Heavy load conditions would greatly speed up the failure of skid resistance. According to the sieving results, the stable gradation of 10-16 mm, 5-10 mm, 3-5 mm, and 0-3 mm after heavy load grinding was 10%, 37%, 23%, and 30%. It was found that the content of 10-16 mm had a significant correlation with the permanent deformation of the asphalt mixture, while there were no significant correlation between aggregate and skid resistance.