The autophagy-related protein Atg2 maintains intestinal homeostasis by preventing lipid accumulation and microbial dysbiosis; however, the mechanisms by which these pathologies interconnect remain unknown. We identify a microbiota‒metabolite‒epigenome axis through which Atg2 deficiency triggers metabolic‒immune cascades in the Drosophila intestine. Tissue-specific Atg2 depletion disrupts autophagic flux, provoking commensal overgrowth and pathogenic overproduction of short-chain fatty acids (SCFAs). Elevated SCFAs drive acetyl-CoA overflow, inducing global protein hyperacetylation that simultaneously activates lipogenic programs and primes innate immunity. Crucially, microbiota ablation or SCFAs restriction fully reverses lipid–immune dysregulation, mechanistically linking microbial metabolites to host pathophysiology. Our work establishes Atg2 as a guardian of microbiota-derived metabolite signaling, demonstrating that autophagy constrains microbial byproducts to prevent acetyl-CoA-mediated epigenetic hijacking of metabolic and immune networks. These findings reveal protein acetylation as a convergent regulator linking commensal ecology to host physiology, suggesting metabolite-centric therapies for dysbiosis-associated disorders.

The Regenerating gene (Rgn) family is implicated in mucosal repair and inflammatory disorders, yet its role in synchronizing intestinal stem cell (ISC) proliferation with stress adaptation remains unknown. Using Drosophila genetics, we demonstrate that Rgn deficiency in progenitors disrupts Notch signaling, resulting in the depletion of ISCs and the accumulation of enteroblasts (EBs). This imbalance coincides with insulin/TOR suppression, provoking reactive oxygen species (ROS) accumulation and DNA double-strand breaks. Consequently, CHK2/p53-dependent G2/M arrest and apoptosis drive progenitor loss and intestinal atrophy. Crucially, S6K overexpression rescues ROS accumulation and proliferation defects, and constitutive EGFR or STAT92E activation restores ISC mitotic activity. Rgn serves as a nodal integrator of Notch-driven differentiation, insulin-dependent redox control, and DNA damage surveillance. Its deficiency triggers a conserved degenerative cascade linking metabolic collapse to genomic instability. Our work establishes Drosophila Rgn as a functional analog of human REG proteins in gut regeneration, proposing REG-targeted therapies for inflammatory bowel diseases.

The lymph gland is the main hematopoietic tissue in Drosophila larvae, regulated by multiple signaling pathways and serving as a valuable genetic model for studying hematopoiesis. Investigating hematopoietic mechanisms in Drosophila can provide valuable insights into the pathogenesis of human hematopoietic malignancies. Tsc1 and Tsc2 are tumor suppressor genes mutated in tuberous sclerosis complex, a tumor syndrome. The protein complexes formed by their gene products have attracted considerable interest in the field of signaling research. However, their roles in maintaining hematopoietic homeostasis remain unclear. In this study, we found that knockdown of Tsc1 or Tsc2 in the intermediate zone and cortical zone leads to increased proliferation and differentiation of hemocytes, accompanied by disruption of progenitor cell maintenance in the medullary zone. Aberrant differentiation of lamellocytes was also observed, along with a marked increase in both the size and number of circulating hemocytes. Furthermore, Tsc1 or Tsc2 knockdown elevated levels of cell death in both the lymph gland and circulating hemocytes. Our findings suggest that Tsc1 and Tsc2 play multifaceted roles in regulating hematopoietic homeostasis through the TOR and Notch signaling pathways. Additionally, Tsc2 contributes to hematopoietic regulation via the JNK pathway and is also involved in apoptosis regulation. In conclusion, our findings revealed that Tsc1 and Tsc2 function within the intermediate zone and cortical zone of the lymph gland to maintain hematopoietic homeostasis through multiple signaling pathways.

The pine wood nematode Bursaphelenchus xylophilus (B. xylophilus) is the main cause of pine wilt disease, a devastating forest disease that leads to considerable economic losses. Currently, trunk injection of chemical nematicides is one of the most widely used approaches for controlling the spread of B. xylophilus. Although this approach has been shown to be effective, prolonged use of chemical pesticides is toxic to the ecosystem and can cause nematode resistance. Therefore, developing plant-derived nematicides with low environmental toxicity is necessary. In this study, we treated pine wood nematodes with different concentrations of 3-indoleacetonitrile (IAN) and showed that this compound significantly inhibited their survival, locomotion, and fecundity. Furthermore, IAN induced elevated reactive oxygen species levels (ROS), lipid accumulation, and cell death, which resulted in severe oxidative stress. We also conducted a transcriptome analysis of B. xylophilus to investigate the genes and pathways affected by IAN, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that the effects of IAN were strongly associated with oxidoreductase activity and the cytochrome P450 (CYP450) pathway. These findings suggest that IAN, a plant-derived compound, possesses promising nematicidal properties.

Diabetes mellitus is a complex metabolic disorder characterized by chronic hyperglycemia, primarily due to defects in insulin secretion and action. With an alarming rise in prevalence, diabetes poses a significant global health threat, particularly type 2 diabetes, which affects more than 90 % of patients and is associated with insulin resistance and various complications. Given the side effects of current antidiabetic drugs, new therapeutic strategies, particularly those involving natural products, are urgently needed. Crocin, a water-soluble carotenoid derived from saffron (Crocus sativus L.), is a food coloring and flavoring agent that has a range of beneficial effects, including anti-inflammatory and antioxidant properties, and has potential as a therapeutic agent for diabetes, although the underlying mechanism is not very clear. In this study, we utilized the model organism Drosophila melanogaster to investigate the effects of crocin on type 2 diabetes. We established a type 2 diabetes model using a high-sugar diet, which resulted in delayed growth, reduced body size, larger lipid droplets, and disrupted intestinal homeostasis. These impairments were alleviated by crocin supplementation. Further validation in insulin pathway mutants revealed the role of crocin in modulating the insulin signaling pathway. Additionally, network pharmacology analysis provided insights into the interactions between crocin and key components of the insulin pathway. Our findings highlight the potential of crocin as a candidate for diabetes management and provide a theoretical basis for the use of plant-derived natural products in diabetes treatment.

Notch signaling is a highly conserved pathway between mammals and Drosophila and plays a key role in various biological processes. Drosophila has emerged as a powerful model for studying hematopoiesis and leukemia. In exception to crystal cells, the strength of Notch signaling in Drosophila lymph gland cortical zone (CZ) / intermediate zone (IZ) cells is weak. However, the influence of Notch activation in the lymph gland CZ/IZ cells and circulating hemocytes on hematopoietic homeostasis maintenance is unclear. Here, we showed that Notch activation in lymph gland CZ/IZ cells induced overdifferentiation of progenitors. Moreover, Notch activation promoted lamellocyte generation via NFκB/Toll signaling activation and increased reactive oxygen species (ROS). In addition, we found that Notch activation in lymph gland CZ/IZ cells and circulating hemocytes caused caspase-independent and nonautophagic cell death. However, crystal cell autophagy was activated by upregulation of the expression of the target gene of the Hippo/Yki pathway Diap1. Moreover, we showed that Notch activation could alleviate cytokine storms and improve the survival of Rasv12 leukemia model flies. Our study revealed the various mechanisms of hematopoietic dysregulation induced by Notch activation in healthy flies and the therapeutic effect of Notch activation on leukemia model flies.

In biomedical research, the fruit fly (Drosophila melanogaster) is among the most effective and flexible model organisms. Through the use of the Drosophila model, molecular mechanisms of human diseases can be investigated and candidate pharmaceuticals can be screened. White rot fungus Inonotus obliquus is a member of the family Hymenochaetaceae. Due to its multifaceted pharmacological effects, this fungus has been the subject of scientific investigation. Nevertheless, the precise mechanisms by which Inonotus obliquus treats diseases remain unclear. In this study, we prepared an aqueous extract derived from Inonotus obliquus and demonstrated that it effectively prevented the negative impacts of inflammatory agents on flies, including overproliferation and overdifferentiation of intestinal progenitor cells and decreased survival rate. Furthermore, elevated reactive oxygen species levels and cell death were alleviated by Inonotus obliquus aqueous extract, suggesting that this extract inhibited intestinal inflammation. Additionally, Inonotus obliquus aqueous extract had an impact on the insulin pathway, as it alleviated growth defects in flies that were fed a high-sugar diet and in chico mutants. In addition, we determined the composition of Inonotus obliquus aqueous extract and conducted a network pharmacology analysis in order to identify prospective key compounds and targets. In brief, Inonotus obliquus aqueous extract exhibited considerable potential as a therapeutic intervention for human diseases. Our research has established a foundational framework that supports the potential clinical implementation of Inonotus obliquus.

Ethnopharmacological relevanceOrostachys malacophylla (Pall.) Fisch (O. malacophylla) is a succulent herbaceous plant that is the Orostachys genus of Crassulaceae family. O. malacophylla has been widely used as a traditional Chinese medicine with antioxidant, anti-inflammatory, anti-febrile, antidote, anti-Toxoplasma gondii properties. However, the biological function of alleviating intestinal inflammation and key bioactive compounds were still unknown.Aim of the studyWe used a Drosophila model to study the protective effects and bioactive compounds of O. malacophylla water extract (OMWE) and butanol extract (OMBE) on intestinal inflammation.Materials and methodsDrosophila intestinal inflammation was induced by oral invasion of dextran sodium sulfate (DSS) or Erwinia carotovora carotovora 15 (Ecc15). We revealed the protective effects of two extracts by determining intestinal reactive oxygen species (ROS) and antimicrobial peptide (AMP) levels and intestinal integrity, and using network pharmacology analysis to identify bioactive compounds.ResultsWe demonstrated that both OMWE and OMBE could ameliorate the detrimental effects of DSS, including a decreased survival rate, elevated ROS levels, increased cell death, excessive proliferation of ISCs, acid-base imbalance, and disruption of intestinal integrity. Moreover, the overabundance of lipid droplets (LDs) and AMPs by Ecc15 infection is mitigated by these extracts, thereby enhancing the flies' resistance to adverse stimuli. In addition, we used widely targeted metabolomics and network pharmacology analysis to identify bioactive compounds associated with IBD healing that are present in OMWE and OMBE.ConclusionsIn summary, our research indicates that OMWE and OMBE significantly mitigate intestinal inflammation and have the potential to be effective therapeutic agents for IBD in humans.

Hematopoiesis is crucial for organismal health,and Drosophila serves as an effective genetic model due to conserved regulatory mechanisms with vertebrates.In larvae,hematopoiesis primarily occurs in the lymph gland,which contains distinct zones,including the cortical zone,intermediate zone,medullary zone,and posterior signaling center(PSC).Rab1 is vital for membrane trafficking and maintaining the localization of cell adhesion molecules,yet its role in hematopoietic homeostasis is not fully understood.This study in-vestigates the effects of Rab1 dysfunction on β-integrin trafficking within circulating hemocytes and lymph gland cells.Rab1 impairment disrupts the endosomal trafficking of β-integrin,leading to its abnormal localization on cell membranes,which promotes lamellocyte differentiation and alters progenitor dynamics in circulating hemocytes and lymph glands,respectively.We also show that the mislocalization of β-integrin is dependent on the adhesion protein DE-cadherin.The reduction of β-integrin at cell boundaries in PSC cells leads to fewer PSC cells and lamellocyte differentiation.Furthermore,Rab1 regulates the trafficking ofβ-integrin via the Q-SNARE protein Syntaxin 17(Syx17).Our findings indicate that Rab1 and Syx17 regulate distinct trafficking pathways for β-integrin in different hematopoietic compartments and maintain he-matopoietic homeostasis of Drosophila.

Aim: Aging is a process characterized by a time-dependent decline in the functionality of adult stem cells and is closely associated with age-related diseases. However, understanding how aging promotes disease and its underlying causes is critical for combating aging. Main methods: The offspring of UAS-Gal4 and CG12744RNAi Drosophila were cultured for 33 days to evaluate the role of CG12744 in the aging intestine. Immunofluorescence was performed to detect specific cell type markers for assessing proliferation and differentiation. qRT-PCR was used to observe the changes in signaling regulating intestinal homeostasis in the aging intestine after CG12744 knockdown. 16S rRNA-seq analysis was also conducted to elucidate the role of gut microbes in CG12744-mediated intestinal dysfunction. Key findings: The mRNA levels of CG12744 were significantly increased in the aged midguts. Knockdown of CG12744 in progenitor cells further exacerbates the age-related intestinal hyperplasia and dysfunction. In particular, upon depletion of CG12744 in progenitors, enteroblasts (EBs) exhibited an increased propensity to differentiate along the enteroendocrine cell (EE) lineage. In contrast, the overexpression of CG12744 in progenitor cells restrained age-related gut hyperplasia in Drosophila. Moreover, CG12744 prevented age-related intestinal stem cell (ISC) overproliferation and differentiation by modulating the EGFR, JNK, and BMP pathways. In addition, the inhibition of CG12744 resulted in a significant increase in the gut microbial composition in aging flies. Significance: This study established a role for the CG12744 in regulating the proliferation and differentiation of adult stem cells, thereby identifying a potential therapeutic target for diseases caused by age-related dysfunction stem cell dysfunction.

Abstract Background The intestinal epithelial barrier is the first line of defense against pathogens and noxious substances entering the body from the outside world. Through proliferation and differentiation, intestinal stem cells play vital roles in tissue regeneration, repair, and the maintenance of intestinal homeostasis. Inflammatory bowel disease (IBD) is caused by the disruption of intestinal homeostasis through the invasion of toxic compounds and pathogenic microorganisms. Hylotelephium erythrostictum (Miq.) H. Ohba (H. erythrostictum) is a plant with diverse pharmacological properties, including antioxidant, anti-inflammatory, antidiabetic, and antirheumatic properties. However, the roles of H. erythrostictum and its bioactive compounds in the treatment of intestinal injury are unknown. Methods We examined the protective effects of H. erythrostictum water extract (HEWE) and H. erythrostictum butanol extract (HEBE) on Drosophila intestinal injury caused by dextran sodium sulfate (DSS) or Erwinia carotovoracarotovora 15 (Ecc15). Results Our findings demonstrated that both HEWE and HEBE significantly prolonged the lifespan of flies fed toxic compounds, reduced cell mortality, and maintained intestinal integrity and gut acid‒base homeostasis. Furthermore, both HEWE and HEBE eliminated DSS-induced ROS accumulation, alleviated the increases in antimicrobial peptides(AMPs) and intestinal lipid droplets caused by Ecc15 infection, and prevented excessive ISC proliferation and differentiation by inhibiting the JNK, EGFR, and JAK/STAT pathways. In addition, they reversed the significant changes in the proportions of the gut microbiota induced by DSS. The bioactive compounds contained in H. erythrostictum extracts have sufficient potential for use as natural therapeutic agents for the treatment of IBD in humans. Conclusion Our results suggest that HEWE and HEBE are highly effective in reducing intestinal inflammation and thus have the potential to be viable therapeutic agents for the treatment of gut inflammation. Clinical trial number Not applicable.

The hematopoietic system of Drosophila is a well-established genetic model for studying hematopoiesis mechanisms, which are strictly regulated by multiple signaling pathways. Autophagy-related 2 (Atg2) protein is involved in autophagosome formation through its lipid transfer function; however, other functions in animal development, especially the role of Atg2 in maintaining hematopoietic homeostasis, are unclear. Here, we show that Atg2 knockdown in the cortical zone (CZ) induced the proliferation and differentiation of mature plasmatocytes and disrupted progenitor maintenance in the medullary zone (MZ). We also observed the differentiation of lamellocytes among circulating hemocytes and in the lymph gland, which is rarely observed in healthy larvae. The above results on hematopoiesis disorders are due to Atg2 regulating the Drosophila PDGF/VEGF receptor (PVR) and target of rapamycin (TOR) in the CZ of lymph gland. In conclusion, we identified Atg2 as a previously undescribed regulator of hematopoiesis. Understanding the mechanism of maintenance of hematopoietic homeostasis in Drosophila will help us better evaluate human blood disorder-related diseases.

To maintain the integrity of the adult gut, the proliferation and differentiation of stem cells must be strictly controlled. Several signaling pathways control the proliferation and differentiation of Drosophila intestinal epithelial cells. Although the modulatory effects of insulin pathway components on cell proliferation have been characterized, their specific role in which cell type and how these components interact with other regulatory signaling pathways remain largely unclear. In this study, we found that InR/Pi3K has major functions in enteroblasts (EBs) that were not previously described. The absence of InR/Pi3K in progenitors leads to a decrease in the number of EBs, while it has no significant effect on intestinal stem cells (ISCs). In addition, we found that InR/Pi3K regulates Notch activity in ISCs and EBs in an opposite way. This is also the reason for the decrease in EB. On the one hand, aberrantly low levels of Notch signaling in ISCs inhibit their proper differentiation into EBs; on the other hand, the higher Notch levels in EBs promote their excessive differentiation into enterocytes (ECs), leading to marked increases in abnormal ECs and decreased proliferation. Moreover, we found that Upd/JAK/STAT signaling acts as an effector or modifier of InR/Pi3K function in the midgut and cooperates with EGFR signaling to regulate cell proliferation. Altogether, our results demonstrate that InR and Pi3K are essential for coordinating stem cell differentiation and proliferation to maintain intestinal homeostasis.

WNT signaling is fundamental in development and homeostasis, but how the Frizzled receptors (FZDs) propagate signaling remains enigmatic. Here, we present the cryo-EM structure of FZD4 engaged with the DEP domain of Dishevelled 2 (DVL2), a key WNT transducer. We uncover a distinct binding mode where the DEP finger-loop inserts into the FZD4 cavity to form a hydrophobic interface. FZD4 intracellular loop 2 (ICL2) additionally anchors the complex through polar contacts. Mutagenesis validates the structural observations. The DEP interface is highly conserved in FZDs, indicating a universal mechanism by which FZDs engage with DVLs. We further reveal that DEP mimics G-protein/β-arrestin/GRK to recognize an active conformation of receptor, expanding current GPCR engagement models. Finally, we identify a distinct FZD4 dimerization interface. Our findings delineate the molecular determinants governing FZD/DVL assembly and propagation of WNT signaling, providing long-sought answers underlying WNT signal transduction. Here the authors report the cryo-EM structure of Frizzeled 4 in complex with the DEP domain of Dishevelled 2. The study unveils the key mechanism of WNT signalling activation, the recruitment of dishevelled to Frizzled receptor.

Adipocytes represent a significant proportion of breast tissue, comprising between 3.7 and 37

The Drosophila lymph gland is an ideal model for studying hematopoiesis, and unraveling the mechanisms of Drosophila hematopoiesis can improve our understanding of the pathogenesis of human hematopoietic malignancies. Bone morphogenetic protein (BMP) signaling is involved in a variety of biological processes and is highly conserved between Drosophila and mammals. Decapentaplegic (Dpp)/BMP signaling is known to limit posterior signaling center (PSC) cell proliferation by repressing the protooncogene dmyc. However, the role of two other TGF-β family ligands, Glass bottom boat (Gbb) and Screw (Scw), in Drosophila hematopoiesis is currently largely unknown. Here, we showed that the loss of Gbb in the cortical zone (CZ) induced lamellocyte differentiation by overactivation of the EGFR and JNK pathways and caused excessive differentiation of plasmatocytes, mainly by the hyperactivation of EGFR. Furthermore, we found that Gbb was also required for preventing the hyperproliferation of the lymph glands by inhibiting the overactivation of the Epidermal Growth Factor Receptor (EGFR) and c-Jun N-terminal Kinase (JNK) pathways. These results further advance our understanding of the roles of Gbb protein and the BMP signaling in Drosophila hematopoiesis and the regulatory relationship between the BMP, EGFR, and JNK pathways in the proliferation and differentiation of lymph gland hemocytes.

Autophagy is a process that promotes the lysosomal degradation of cytoplasmic proteins and is highly conserved in eukaryotic organisms. Autophagy maintains homeostasis in organisms and regulates multiple developmental processes, and autophagy disruption is related to human diseases. However, the functional roles of autophagy in mediating innate immune responses are largely unknown. In this study, we sought to understand how Atg2, an autophagy-related gene, functions in the innate immunity of Drosophila melanogaster. The results showed that a large number of melanotic nodules were produced upon inhibition of Atg2. In addition, inhibiting Atg2 suppressed the phagocytosis of latex beads, Staphylococcus aureus and Escherichia coli; the proportion of Nimrod C1 (one of the phagocytosis receptors)-positive hemocytes also decreased. Moreover, inhibiting Atg2 altered actin cytoskeleton patterns, showing longer filopodia but with decreased numbers of filopodia. The expression of AMP-encoding genes was altered by inhibiting Atg2. Drosomycin was upregulated, and the transcript levels of Attacin-A, Diptericin and Metchnikowin were decreased. Finally, the above alterations caused by the inhibition of Atg2 prevented flies from resisting invading pathogens, showing that flies with low expression of Atg2 were highly susceptible to Staphylococcus aureus and Erwinia carotovora carotovora 15 infections. In conclusion, Atg2 regulated both cellular and humoral innate immunity in Drosophila. We have identified Atg2 as a crucial regulator in mediating the homeostasis of immunity, which further established the interactions between autophagy and innate immunity.

Drosophila is often exposed to harmful environments, and the intestinal epithelium is the first line of defense against external infection. Intestinal stem cells (ISCs) in the Drosophila midgut play a crucial role in maintaining tissue homeostasis and compensating for cell loss caused by tissue damage. Crocus sativus L. (saffron) can protect against intestinal injury in response to inflammation; however, the specific protective components of saffron and the related mechanisms remain unclear. Safranal is one of the main components of saffron. Here, we used dextran sodium sulfate (DSS) or Erwinia carotovora carotovora 15 (Ecc15) to create an intestinal injury model and explored the protective effect of safranal against tissue damage. Excessive proliferation and differentiation of ISCs in the Drosophila midgut were observed after DSS or Ecc15 feeding; however, these phenotypes were rescued after safranal feeding. In addition, we found that this process occurred through inhibition of the c-Jun N-terminal kinase (JNK), epidermal growth factor receptor (EGFR) and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways. Furthermore, safranal inhibited the Ecc15- and DSS-induced increases in antimicrobial peptide (AMP) and reactive oxygen species (ROS) levels and intestinal epithelial cell death, thereby protecting gut integrity. In summary, safranal was found to have a significant protective effect and maintain intestinal homeostasis in Drosophila; these findings provide a foundation for the application of safranal in clinical research and the treatment of intestinal injury.