Bombyx mori nuclear polyhedrosis virus (BmNPV) is an important pathogen of silkworms. Despite extensive studies in recent decades, the interaction between BmNPV and host cells is still not clearly understood. Autophagy is an intrinsic innate immune mechanism and it controls infection autonomously in virus-infected cells. In this study, we found that BmNPV infection could trigger autophagy, as demonstrated by the formation of autophagosomes, fluorescent Autophagy-related gene 8-Green Fluorescent Protein (ATG8-GFP) punctate, and lipidated ATG8. Meanwhile, autophagic flux increased significantly when monitored by the ATG8-GFP-Red Fluorescent Protein (RFP) autophagy tandem sensor and protein degradation of p62. In addition, almost all of the identified autophagy-related genes (Atgs) had been up-regulated post infection in mRNA levels. Then, we screened Atgs with the greatest fold-change during virus infection. Interestingly, all of the screened Atgs positively regulated the expression of virus genes. Further studies showed that Atg7 and Atg9 could contribute to the level of autophagy caused by viral infection. Our results demonstrated that BmNPV induced host cell autophagy to benefit its infection. These results offer insight into the complex interactions between virus and host cell, and viral pathogenesis.

Silk gland cells undergo multiple endomitotic cell cycles during silkworm larval ontogeny. Our previous study demonstrated that feeding is required for continued endomitosis in the silk gland cells of silkworm larvae. Furthermore, the insulin signaling pathway is closely related to nutritional signals. To investigate whether the insulin signaling pathway is involved in endomitosis in silk gland cells, in this study, we initially analyzed the effects of bovine insulin on DNA synthesis in endomitotic silk gland cells using 5-bromo-2'-deoxyuridine (BrdU) labeling technology, and found that bovine insulin can stimulate DNA synthesis. Insulin signal transduction is mainly mediated via phosphoinositide 3-kinase (PI3K)/Akt, the target of rapamycin (TOR) and the extracellular signal-regulated kinase (ERK) pathways in vertebrates. We ascertained that these three pathways are involved in DNA synthesis in endomitotic silk gland cells using specific inhibitors against each pathway. Moreover, we investigated whether these three pathways are involved in insulin-stimulated DNA synthesis in endomitotic silk gland cells, and found that the PI3K/Akt and TOR pathways, but not the ERK pathway, are involved in this process. These results provide an important theoretical foundation for the further investigations of the mechanism underlying efficient endomitosis in silk gland cells.

Background: Sepsis is defined as a life‐threatening disease. Autophagy and the microbiome are increasingly connected with sepsis. The aim of this study was to investigate the protective effect of autophagy and the possible mechanisms.Methods: The septic rat model was established by cecal ligation perforation (CLP). Rapamycin (Rap), 3‐methyladenine (3‐MA), and chloroquine (CQ) were administered to interfere autophagy. Western blot (WB) was used to detect the expression of key proteins in autophagy. Hematoxylin and eosin (H&E) staining and enzyme‐linked immunosorbent assays (ELISAs) were used to identify the effect of autophagy on various organs. 16S ribosomal RNA gene sequencing was used to analyze the changes of the gut microbiota.Results: Rap significantly upregulated the expression of key autophagy proteins, and 3‐MA reduced the relative expression compared to the CLP group. The autophagic flux showed a corresponding trend. Interestingly, the autophagy inducer significantly decreased the mortality and the lipopolysaccharide (LPS) level in serum compared with the CLP group. Autophagy activation significantly improves the inflammatory response in sepsis. Histopathological sections showed that CLP destroyed the tight junctions between ileal epithelial cells, while autophagy induction reversed the damage. The sequencing results showed that autophagy activation increased the alpha diversity and alterted the composition and structure of gut microbiota. The abundance of Proteobacteria was markedly decreased in the Rap group, whereas Bacteroidetes was notably increased compared with the CLP group. Additionally, the protective effect of autophagy further changed the biomarkers in the microbial community. The top 35 functions in each sample were analyzed to obtain 18 genes including RNA synthesis, ATP binding and transport, chromosome assignment, osmotic polysaccharide transport, transcytosis, and methylation.Conclusion: Autophagy is able to improve inflammation and may directly or indirectly regulate the microbiota of septic rats. Autophagy may be an important target for future clinical interventions in the treatment of sepsis.

Background: Metabolic dysfunction–associated steatotic liver disease (MASLD) is a highly prevalent chronic liver disorder for which effective pharmacological interventions remain limited, particularly at early stages. Geniposide (GP), a major bioactive component derived from the fruit of Gardenia jasminoides , has been reported to exert hepatoprotective, anti‐inflammatory, and antioxidant effects; however, its molecular mechanisms in MASLD have not been fully elucidated. Methods: An MASLD mouse model was established by feeding ApoE knockout mice a high‐fat diet (HFD), followed by GP treatment for 8 weeks. Hepatic steatosis, lipid metabolism, oxidative stress, and inflammatory responses were evaluated using biochemical assays, histopathological analysis, and immunofluorescence. Unbiased Astral data‐independent acquisition (Astral‐DIA) proteomics was performed to identify differentially expressed proteins and enriched signaling pathways. In vitro validation was conducted using palmitic acid (PA)–treated THLE‐2 human hepatocytes. Results: GP treatment significantly alleviated hepatic steatosis and lipid metabolic disorder in HFD‐fed mice. Compared with the HFD group, GP reduced serum TG levels from 1.38 ± 0.15 to 0.79 ± 0.10 mM ( p < 0.05) and hepatic TG content from 3.15 ± 0.47 to 2.21 ± 0.28 mmol/g protein ( p < 0.05). Proteomic analysis identified more than 7600 proteins and revealed CYP4A family members as prominent GP‐responsive proteins, with Cyp4a10 and Cyp4a14 reduced by approximately 62% and 71%, respectively. Consistently, GP decreased hepatic 20‐HETE levels from 114.6 ± 28.52 to 80.63 ± 19.12 ng/mg protein ( p < 0.05) and reduced oxidative and inflammatory responses, including decreased serum IL‐6 from 127.3 ± 42.27 to 77.67 ± 23.55 pg/mL and TNF‐α from 44.18 ± 10.47 to 28.58 ± 8.53 pg/mL (both p < 0.05). In vitro, GP restored PA‐reduced THLE‐2 cell viability from 69.0 ± 7.0% to 88.0 ± 8.0% of the control level ( p < 0.05) and decreased intracellular 20‐HETE levels from 60.77 ± 9.06 to 40.28 ± 7.82 ng/mg protein ( p < 0.05). GP also attenuated PA‐induced lipid accumulation, ROS generation, inflammatory cytokine secretion, and apoptosis. Pharmacological inhibition of 20‐HETE synthesis partially recapitulated these protective effects, supporting the involvement of the CYP4A/20‐HETE axis in hepatocyte lipotoxicity. Conclusions: GP ameliorates MASLD by attenuating hepatocyte lipotoxic injury through coordinated suppression of the CYP4A/20‐HETE axis and downstream ROS/NF‐κB‐mediated oxidative and inflammatory signaling. These findings provide mechanistic insight into the hepatoprotective actions of GP and highlight CYP4A‐associated lipid signaling as a therapeutically relevant pathway for the prevention and early intervention of MASLD.