Stress Buffering and Longevity Effects of Amber Extract on Caenorhabditis elegans (C. elegans)

Polysaccharides from Ziziphus jujuba prolong lifespan and attenuate oxidative stress in Caenorhabditis elegans via DAF-16 and SKN-1

Jujube is a commonly consumed traditional Chinese medicinal food. Recent evidence revealed crude polysaccharides of jujube extract (CPJE) exhibited bioactive properties in vitro; however, its antioxidant capacity in vivo remains unknown. The objectives of this study were to evaluate the effects of CPJE on growth, locomotion, reproduction, lifespan, and antioxidant defense system using Caenorhabditis elegans. Results showed CPJE were not toxic to C. elegans with no effects on bacterial growth. Compared to control, CPJE significantly increased body length and width, head thrashes, body bends, and brood size of nematodes. In addition, CPJE at higher concentrations significantly increased pharyngeal pumping of the nematodes. Moreover, CPJE at 0.25, 0.5, and 1 mg/mL promoted lifespan by 17.9 %, 34.7 % and 46.3 %, respectively. CPJE at higher concentrations reduced level of ROS, increased activities of SOD, CAT, and GSH. CPJE also upregulated the expression of daf-16, skn-1, sod-3, and gcs-1 in N2 nematodes. Meanwhile, results from studies with nematode mutants also suggested that improved stress resistance of CPJE was due to modulation of daf-16 and skn-1. Overall, our results suggest CPJE promote longevity and reduce oxidative stress via DAF-16 and SKN-1. Our findings shed a new light on the utilization of CPJE to attenuate oxidative stress.

Ovalbumin promotes innate immune response of Caenorhabditis elegans through DAF-16 and SKN-1 pathways in insulin/IGF-1 signaling

Ovalbumin (OVA) is a major allergen in eggs and could induce severe allergic reactions in sensitive individuals, where the innate immune system works as a regulator. The mechanism of how innate immunity adjusts to food allergy is relatively well-studied, however, the effects of allergen uptake on the innate immune system remain unclear. Therefore, the Caenorhabditis elegans (C. elegans) model was utilized to assess the effects of OVA on its innate immune system. OVA enhanced the immune response of C. elegans with higher survival rates under Pseudomonas aeruginosa infection. Moreover, sustaining OVA treatment improved the health states that were reflected in the prolonged lifespan, alleviated oxidative stress, accelerated growth, and promoted motility. RNA-sequencing analysis and the slow-killing assays in the mutants of insulin/IGF-1 signaling (IIS)-related genes confirmed that IIS was necessary for OVA to regulate innate immunity. Besides, OVA activated SKN-1 temporarily and facilitated the nuclear localization of DAF-16 for improving immunity and health status in C. elegans. Together, OVA could enhance the innate immune responses via DAF-16 and SKN-1 pathways in the IIS of C. elegans, and this work will provide novel insights into the regulation of innate immunity by OVA in higher organisms.

L-Theanine Prolongs the Lifespan by Activating Multiple Molecular Pathways in Ultraviolet C-Exposed Caenorhabditis elegans

L-theanine, a unique non-protein amino acid, is an important bioactive component of green tea. Previous studies have shown that L-theanine has many potent health benefits, such as anti-anxiety effects, regulation of the immune response, relaxing neural tension, and reducing oxidative damage. However, little is known concerning whether L-theanine can improve the clearance of mitochondrial DNA (mtDNA) damage in organisms. Here, we reported that L-theanine treatment increased ATP production and improved mitochondrial morphology to extend the lifespan of UVC-exposed nematodes. Mechanistic investigations showed that L-theanine treatment enhanced the removal of mtDNA damage and extended lifespan by activating autophagy, mitophagy, mitochondrial dynamics, and mitochondrial unfolded protein response (UPRmt) in UVC-exposed nematodes. In addition, L-theanine treatment also upregulated the expression of genes related to mitochondrial energy metabolism in UVC-exposed nematodes. Our study provides a theoretical basis for the possibility that tea drinking may prevent mitochondrial-related diseases.