The polysaccharide glycogen is an evolutionarily conserved storage form of glucose. However, the physiological significance of glycogen metabolism on homeostatic control throughout the animal life cycle remains incomplete. Here, we report a Drosophila fruit fly that is defective for glycogen metabolism. Null mutants of glycogen synthase (GlyS) and glycogen phosphorylase (GlyP) displayed growth defects and larval lethality, indicating that glycogen plays a crucial role in larval development. Unexpectedly, however, a certain population of larvae developed into adults with normal morphology. Semi-lethality in glycogen mutants during the larval period can be attributed to the presence of circulating sugar trehalose. Homozygous glycogen mutants produced offspring, indicating that glycogen stored in oocytes is dispensable for embryogenesis. GlyS and GlyP mutants showed distinct metabolic defects in the levels of circulating sugars and triglycerides in a life stage-specific manner. In adults, glycogen as an energy reserve is not crucial for physical fitness and lifespan under nourished conditions, but glycogen becomes important under energy stress conditions. This study provides a fundamental understanding of the stage-specific requirements for glycogen metabolism in the fruit fly.

One way that aerobic biological systems counteract the generation of reactive oxygen species (ROS) is with superoxide dismutase proteins SOD1 and SOD2 that metabolize superoxide radicals to molecular oxygen and hydrogen peroxide or scavenge oxygen radicals produced by the extensive oxidation-reduction and electron-transport reactions that occur in mitochondria. We characterized SOD1 and SOD2 of Bombyx mori isolated from the fat body of larvae. Immunological analysis demonstrated the presence of BmSOD1 and BmSOD2 in the silk gland, midgut, fat body, Malpighian tubules, testis and ovary from larvae to adults. We found that BmSOD2 had a unique expression pattern in the fat body through the fifth instar larval developmental stage. The anti-oxidative functions of BmSOD1 and BmSOD2 were assessed by exposing larvae to insecticide rotenone or vasodilator isosorbide dinitrate, which is an ROS generator in BmN4 cells; however, exposure to these compounds had no effect on the expression levels of either BmSOD protein. Next, we investigated the physiological role of BmSOD1 and BmSOD2 under environmental oxidative stress, applied through whole-body UV irradiation and assayed using quantitative RT-PCR, immunoblotting and microarray analysis. The mRNA expression level of both BmSOD1 and BmSOD2 was markedly increased but protein expression level was increased only slightly. To examine the differences in mRNA and protein level due to UV irradiation intensity, we performed microarray analysis. Gene set enrichment analysis revealed that genes in the insulin signaling pathway and PPAR signaling pathway were significantly up-regulated after 6 and 12 hours of UV irradiation. Taken together, the activities of BmSOD1 and BmSOD2 may be related to the response to UV irradiation stress in B. mori. These results suggest that BmSOD1 and BmSOD2 modulate environmental oxidative stress in the cell and have a specific role in fat body of B. mori during pupation.

Insects are well adapted to changing environmental conditions. They have unique systems for eliminating reactive oxygen species (ROS). Superoxide dismutase (SOD) is a key enzyme that plays a primary role in removing ROS. Bombyx mori is a lepidopteran insect, whose body size is larger than the model insect Drosophila melanogaster, which enabled us to more easily examine gene expression at the tissue level. We searched B. mori SOD (BmSOD) genes using genome database, and we analyzed their function under different type of oxidative stress. Consequently, we identified four new types of BmSODs in addition to the three types already known. Two of the seven types had a unique domain architecture that has not been discovered previously in the SOD family, and they were expressed in different tissues and developmental stages. Furthermore, these BmSODs responded differently to several kinds of stressors. Our results showed that the seven types of BmSODs are likely to play different roles in B. mori; therefore, B. mori could be used to distinguish the functions of each SOD for resistance to oxidative stress that changes with the environmental conditions.

There is an unmet need for novel biomarkers in the diagnosis of multifactorial COPD. We applied next-generation proteomics to serum extracellular vesicles (EVs) to discover novel COPD biomarkers.EVs from 10 patients with COPD and six healthy controls were analysed by tandem mass tag-based non-targeted proteomics, and those from elastase-treated mouse models of emphysema were also analysed by non-targeted proteomics. For validation, EVs from 23 patients with COPD and 20 healthy controls were validated by targeted proteomics.Using non-targeted proteomics, we identified 406 proteins, 34 of which were significantly upregulated in patients with COPD. Of note, the EV protein signature from patients with COPD reflected inflammation and remodelling. We also identified 63 upregulated candidates from 1956 proteins by analysing EVs isolated from mouse models. Combining human and mouse biomarker candidates, we validated 45 proteins by targeted proteomics, selected reaction monitoring. Notably, levels of fibulin-3, tripeptidyl-peptidase 2, fibulin-1, and soluble scavenger receptor cysteine-rich domain-containing protein were significantly higher in patients with COPD. Moreover, six proteins; fibulin-3, tripeptidyl-peptidase 2, UTP-glucose-1-phosphate uridylyl transferase, CD81, CD177, and oncoprotein-induced transcript 3, were correlated with emphysema. Upregulation of fibulin-3 was confirmed by immunoblotting of EVs and immunohistochemistry in lungs. Strikingly,fibulin-3knockout mice spontaneously developed emphysema with age, as evidenced by alveolar enlargement and elastin destruction.We discovered potential pathogenic biomarkers for COPD using next-generation proteomics of EVs. This is a novel strategy for biomarker discovery and precision medicine.

Drug resistance often stems from drug-tolerant persister (DTP) cells in cancer. These cells arise from various lineages and exhibit complex dynamics. However, effectively targeting DTP cells remains challenging. We used single-cell RNA sequencing (scRNA-Seq) data and machine learning (ML) models to identify DTP cells in patient-derived organoids (PDOs) and computationally screened candidate drugs targeting these cells in familial adenomatous polyposis (FAP), associated with a high risk of colorectal cancer. Three PDOs (benign and malignant tumor organoids and a normal organoid) were evaluated using scRNA-Seq. ML models constructed based on public scRNA-Seq data classified DTP versus non-DTP cells. Candidate drugs for DTP cells in a malignant tumor organoid were identified from public drug sensitivity data. From FAP scRNA-Seq data, a specific TC1 cell cluster in tumor organoids was identified. The ML model identified up to 36 % of TC1 cells as DTP cells, a higher proportion than those for other clusters. A viability assay using a malignant tumor organoid demonstrated that YM-155 and THZ2 exert synergistic effects with trametinib. The constructed ML model is effective for DTP cell identification based on scRNA-Seq data for FAP and provides candidate treatments. This approach may improve DTP cell targeting in the treatment of colorectal and other cancers.

Perhaps, oxidative stress progresses pupation in some Lepidopteran insects; however, the reasons for this remain obscure. In our previous study, we clarifiedBombyx moriSOD1 (BmSOD1) andB. moriSOD2 (BmSOD2) proteins respond in common to ultraviolet irradiation (UV) oxidative stress and metamorphosis. This result strongly suggested pupation initiates by oxidative stress and might mediate by down-regulation of expression of BmSOD1 and BmSOD2 proteins. Thus, we examined about these relationships inB. moriin this study. In the microarray data reanalysis, we found the Notch signaling pathways as the common pathways in pupation and UV oxidative stress inB. mori. Also, we showed a molting hormone, 20-hydroxyecdysone, leads not only generation of superoxide but also downregulation of the expression of BmSOD proteins during pupation inB. mori. Our findings can contribute to a deeper understanding of how biological defense systems work against environmental oxidative stress.