Complement C3 participates in the development of goose fatty liver potentially by regulating the expression of FASN and ETNK1

The Complement System, Aging, and Aging-Related Diseases

The complement system is a part of the immune system and consists of multiple complement components with biological functions such as defense against pathogens and immunomodulation. The complement system has three activation pathways: the classical pathway, the lectin pathway, and the alternative pathway. Increasing evidence indicates that the complement system plays a role in aging. Complement plays a role in inflammatory processes, metabolism, apoptosis, mitochondrial function, and Wnt signaling pathways. In addition, the complement system plays a significant role in aging-related diseases, including Alzheimer’s disease, age-related macular degeneration, and osteoarthritis. However, the effect of complement on aging and aging-related diseases is still unclear. Thus, a better understanding of the potential relationship between complement, aging, and aging-related diseases will provide molecular targets for treating aging, while focusing on the balance of complement in during treatment. Inhibition of a single component does not result in a good outcome. In this review, we discussed the research progress and effects of complement in aging and aging-related diseases.

Betaine Promotes Fat Accumulation and Reduces Injury in Landes Goose Hepatocytes by Regulating Multiple Lipid Metabolism Pathways

Betaine is a well-established supplement used in livestock feeding. In our previous study, betaine was shown to result in the redistribution of body fat, a healthier steatosis phenotype, and an increased liver weight and triglyceride storage of the Landes goose liver, which is used for foie-gras production. However, these effects are not found in other species and strains, and the underlying mechanism is unclear. Here, we studied the underpinning molecular mechanisms by developing an in vitro fatty liver cell model using primary Landes goose hepatocytes and a high-glucose culture medium. Oil red-O staining, a mitochondrial membrane potential assay, and a qRT-PCR were used to quantify lipid droplet characteristics, mitochondrial β-oxidation, and fatty acid metabolism-related gene expression, respectively. Our in vitro model successfully simulated steatosis caused by overfeeding. Betaine supplementation resulted in small, well-distributed lipid droplets, consistent with previous experiments in vivo. In addition, mitochondrial membrane potential was restored, and gene expression of fatty acid synthesis genes (e.g., sterol regulatory-element binding protein, diacylglycerol acyltransferase 1 and 2) was lower after betaine supplementation. By contrast, the expression of lipid hydrolysis transfer genes (mitochondrial transfer protein and lipoprotein lipase) was higher. Overall, the results provide a scientific basis and theoretical support for the use of betaine in animal production.