Variation of lifespan in multiple strains, and effects of dietary restriction and BmFoxO on lifespan in silkworm, Bombyx mori

Transcriptomics analyses combined with intestinal microorganism survey suggest Resveratrol (RSV) anti-aging and anti-oxidant effects in silkworm (Bombyx mori)

The growing elderly population presents a significant concern, with the prolongation of life expectancy, aging diseases are becoming increasingly common. Resveratrol (RSV) has emerged as a promising compound for disease prevention. However, the effect of RSV on lifespan extension in different organisms, particularly the model organism silkworm, remains inconsistent. We conducted aging experiments using silkworm (B. mori) and employed transcriptomics to investigate the therapeutic effects of RSV on lifespan extension and healthy lifespan in silkworms. RSV increased the survival rate by 8.57 %-12.12 % and enhanced the antioxidant capacity of silkworms. Transcriptomic analysis demonstrated that genes in signaling pathways such as AMPK and FoxO were significantly upregulated. 16SrRNA sequencing of gut contents showed an increase in beneficial bacterial strains under the action of RSV. This study aims to enhance our understanding of lifespan regulation mechanisms using the silkworm model and provide new targets for anti-aging antioxidants research to delay the onset of age-related diseases.

Repurposing effect of cardiovascular-metabolic drug to increase lifespan: a systematic review of animal studies and current clinical trial progress

With the increase in life expectancy, aging has emerged as a significant health concern. Due to its various mechanisms of action, cardiometabolic drugs are often repurposed for other indications, including aging. This systematic review analyzed and highlighted the repositioning potential of cardiometabolic drugs to increase lifespan as an aging parameter in animal studies and supplemented by information from current clinical trial registries. Systematic searching in animal studies was performed based on PICO: "animal," "cardiometabolic drug," and "lifespan." All clinical trial registries were also searched from the WHO International Clinical Trial Registry Platform (ICTRP). Analysis of 49 animal trials and 10 clinical trial registries show that various cardiovascular and metabolic drugs have the potential to target lifespan. Metformin, acarbose, and aspirin are the three most studied drugs in animal trials. Aspirin and acarbose are the promising ones, whereas metformin exhibits various results. In clinical trial registries, metformin, omega-3 fatty acid, acarbose, and atorvastatin are currently cardiometabolic drugs that are repurposed to target aging. Published clinical trial results show great potential for omega-3 and metformin in healthspan. Systematic Review Registration: crd.york.ac.uk/prospero/display_record.php?RecordID=457358, identifier: CRD42023457358.

Sex-specific aging in animals: Perspective and future directions

Sex differences in aging occur in many animal species, and they include sex differences in lifespan, in the onset and progression of age-associated decline, and in physiological and molecular markers of aging. Sex differences in aging vary greatly across the animal kingdom. For example, there are species with longer-lived females, species where males live longer, and species lacking sex differences in lifespan. The underlying causes of sex differences in aging remain mostly unknown. Currently, we do not understand the molecular drivers of sex differences in aging, or whether they are related to the accepted hallmarks or pillars of aging or linked to other well-characterized processes. In particular, understanding the role of sex-determination mechanisms and sex differences in aging is relatively understudied. Here, we take a comparative, interdisciplinary approach to explore various hypotheses about how sex differences in aging arise. We discuss genomic, morphological, and environmental differences between the sexes and how these relate to sex differences in aging. Finally, we present some suggestions for future research in this area and provide recommendations for promising experimental designs.

Resveratrol elongates the lifespan and improves antioxidant activity in the silkworm Bombyx mori

A number of research has shown that the plant polyphenol resveratrol, one of the most prominent small molecules, has beneficial protective effects in multiple organisms, including worms, flies, and killifish. To understand the effects of resveratrol on lifespan, we evaluated its effects in the silkworm Bombyx mori. In this study, we found that lifespan was significantly prolonged in both female and male silkworms treated with resveratrol. Silkworm larval weight was significantly increased from day 3 of the 5th larval instar (L5D3) to day 7 of the 5th larval instar (L5D7). However, the weight of the pupa, cocoon, and total cocoon was not significantly different in female silkworms with resveratrol treatment than that in controls. Meanwhile, resveratrol significantly improved the thermotolerance of the silkworms, which enhanced their survival rate. Moreover, antioxidant activity was increased by resveratrol in both female and male silkworms. Furthermore, an antioxidant-related signalling pathway, SIRT7-FoxO-GST, was activated in silkworms with resveratrol treatment. Collectively, these results help us to understand the molecular pathways underlying resveratrol induced pro-longevity effects and indicate that silkworm is a promising animal model for evaluating the effects of lifespan-extending drugs.

Metformin prolongs lifespan through remodeling the energy distribution strategy in silkworm, Bombyx mori

Metformin is a hypoglycemic agent used clinically in the treatment of type 2 diabetics. In addition, metformin is being investigated as a potential geroprotector. Here, we investigated the effects of metformin silkworm lifespan and the underlying molecular pathways involved. We found that metformin prolonged the lifespan of the male silkworm without reducing body weight, which suggests metformin can increase lifespan through remodeling of the animal's energy distribution strategy. Consistent with that idea, metformin reduced silk production and thus the energy devoted to that process. Metformin also increased fasting tolerance and levels of the antioxidant glutathione, and also activated an adenosine monophosphate-activated protein kinase-p53-forkhead box class O signaling pathway in silkworm. These results suggest that activity in this pathway may contribute to metformin-induced lifespan extension in silkworm by increasing stress resistance and antioxidative capacity while reducing energy output for silk product. The results also show that the silkworm is a potential useful animal model for evaluating the effects of small molecules with potential clinical utility.

Astragalus Polysaccharide Extends Lifespan via Mitigating Endoplasmic Reticulum Stress in the Silkworm, Bombyx mori

The traditional Chinese medicine Astragalus polysaccharide (APS) has been widely used to improve glucose homeostasis and immunoregulator properties. In recent years, it has also been shown to extend the lifespan of Caenorhabditis elegans; however, the underlying molecular mechanisms are not fully understood. Here, our study shows that APS could significantly extend adult stage, mean, and maximum lifespan of the silkworm, Bombyx mori and increase body weight without affecting food intake and fecundity. Meanwhile, the activities of glutathione S-transferase and superoxide dismutase are significantly enhanced, and the reaction oxygen species content is reduced concomitantly. Moreover, the activity of lysozyme is increased dramatically. In addition, APS rescues the shortened lifespan by Bacillus thuringiensis infection in silkworm. Furthermore, the transcription of the crucial genes involved in endoplasmic reticulum stress is upregulated upon the endoplasmic reticulum stress stimulation. APS also significantly ameliorates endoplasmic reticulum stress in silkworm cell line and in vivo. Together, the results of this study indicate that APS can prolong the silkworm lifespan by mitigating endoplasmic reticulum stress. This study improves our understanding of the molecular mechanism of APS-induced lifespan extension and highlights the importance of the silkworm as an experimental animal for evaluating the effects and revealing the mechanisms in lifespan extension of traditional Chinese medicine.

Silkworm, Bombyx mori, as an alternative model organism in toxicological research

Silkworms, Bombyx mori, are a promising model animal in health safety and environmental pollution assessment due to their sensitivity to chemical compounds like pesticides, drugs, and heavy metals, in addition to other features like their low cost and body characteristics and their full genome sequencing. In this review, we summarize the silkworm advantages as a model organism in toxicological research. Graphical abstract ᅟ.

Selection of reference genes for tissue/organ samples on day 3 fifth-instar larvae in silkworm, Bombyx mori

The silkworm, Bombyx mori, is one of the world's most economically important insect. Surveying variations in gene expression among multiple tissue/organ samples will provide clues for gene function assignments and will be helpful for identifying genes related to economic traits or specific cellular processes. To ensure their accuracy, commonly used gene expression quantification methods require a set of stable reference genes for data normalization. In this study, 24 candidate reference genes were assessed in 10 tissue/organ samples of day 3 fifth-instar B. mori larvae using geNorm and NormFinder. The results revealed that, using the combination of the expression of BGIBMGA003186 and BGIBMGA008209 was the optimum choice for normalizing the expression data of the B. mori tissue/organ samples. The most stable gene, BGIBMGA003186, is recommended if just one reference gene is used. Moreover, the commonly used reference gene encoding cytoplasmic actin was the least appropriate reference gene of the samples investigated. The reliability of the selected reference genes was further confirmed by evaluating the expression profiles of two cathepsin genes. Our results may be useful for future studies involving the quantification of relative gene expression levels of different tissue/organ samples in B. mori.