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Biology subjects

Ge, D.

Publications and source records attributed to Ge, D..

6 recordsLinked to original sources

ZDHHC17–Mediated Palmitoylation of Hepatitis E Virus ORF3 Protein Regulates Vectorial Trafficking in Polarized Epithelial Cells

The hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide and is transmitted enterically along the gut-liver axis. Epithelial cell polarity in the gut and liver plays a critical role in HEV transmission. In intestinal epithelial cells, HEV enters through the apical membrane and is released basolaterally to access the bloodstream, whereas in hepatocytes, the virus enters basolaterally and is secreted apically into the bile duct. In this study, we sought to identify the viral and host determinants governing directional HEV secretion in both tissue types. Using polarized intestinal and hepatocyte models, we found that the small phosphoprotein ORF3, which is essential for progeny secretion, localizes predominantly to the apical membrane, in contrast to the ORF2 capsid protein. We further identified the palmitoyltransferase ZDHHC17 as a specific ORF3 interactor that mediates its apical localization and promotes HEV progeny release. Using automated cell segmentation and quantitative image analysis, we screened a panel of ORF3 mutants and found that positively charged residues within the N-terminus regulate membrane association. In addition, we identified a conserved PIFIQP motif that mediates the critical interaction with the ankyrin repeat domain (ARD) of ZDHHC17. Leveraging this interaction, we generated high-confidence structural models of ORF3 in complex with the ZDHHC17 ARD using AlphaFold. These models, further validated by molecular dynamics simulations, revealed additional ORF3 residues involved in the interaction. Collectively, our findings define key mechanisms underlying directional HEV release and provide broader insights into trafficking processes in polarized epithelial cells.

Cell Biology↗

Model of leaf biomass partitioning coefficient in different leaf ranks of rapeseed (Brassica napus L.) main-stem

Leaf growth is a dynamic process, and understanding the number of main-stem leaves and the distribution of leaf biomass at different development stages can provide a theoretical basis for the development of functional-structural rapeseed model. To address the gap in research on the leaf biomass partitioning coefficient model in the crop growth model, we developed the leaf biomass partitioning coefficient model for the main-stem at different leaf ranks in rapeseed. The outdoor experiment with cultivars, Ningyou 18 (V1, conventional), Ningyou 16 (V2, conventional), and Ningza 19 (V3, hybrid), and designed treatment of cultivars x fertilizer x transplanting density in the 2012-2015 growth season. The model was fitted by calculating the ratio of leaf biomass at different leaf ranks on the main-stem to the total leaf biomass on the main-stem, and normalizing the leaf ranks into (0-1] interval. We parameterized the model variables to elucidate how cultivar and environmental conditions influence the leaf biomass partitioning coefficients for different leaf ranks. The descriptive models were validated with independent experimental data, the correlation (r) of simulation and observation values all greater than 0.9 with significant levels at p < 0.001. The absolute values of the average absolute difference (da) are all less than 0.011 g g-1. The ratio of da to the average observation (dap) for the normalized leaf rank, and leaf biomass partitioning coefficient at seedling stage, and budding and bolting stage, and blooming stage, and mature stage are 13.599%, 11.236%, 11.312%, 3.077%, and 8.661%, respectively. The RMSE values are all less than 0.032 g g-1. The models developed in this paper have good performance and reliability for predicting leaf biomass partitioning coefficient of main-stem at different leaf ranks in rapeseed. This study integrates the leaf morphology model of rapeseed with the rapeseed growth model through biomass partitioning, contributing to the development of the functional-structural rapeseed model.

bioinformatics↗

Inactivation of a non-canonical gp130 signaling arm attenuates chronic systemic inflammation and multimorbidity induced by a high-fat diet.

Interleukin-6 (IL-6) is a major pro-inflammatory cytokine for which the levels in plasma demonstrate a robust correlation with age and body mass index (BMI) as part of the senescence-associated secretory phenotype. IL-6 cytokines also play a crucial role in metabolic homeostasis and regenerative processes, primarily via the canonical STAT3 pathway. Thus, selective modulation of IL-6 signaling may offer a unique opportunity for therapeutic interventions. Recently, we discovered that a non-canonical signaling pathway downstream of tyrosine (Y) 814 within the intracellular domain of gp130, the IL-6 co-receptor, is responsible for the recruitment and activation of SRC family of kinases (SFK). Mice with constitutive genetic inactivation of gp130 Y814 (F814 mice) show accelerated resolution of inflammatory response and superior regenerative outcomes in skin wound healing and posttraumatic models of osteoarthritis. The current study was designed to explore if selective genetic or pharmacological inhibition of the non-canonical gp130-Y814/SFK signaling reduces systemic chronic inflammation and multimorbidity in a high-fat diet (HFD)-induced model of accelerated aging. F814 mice showed significantly reduced inflammatory response to HFD in adipose and liver tissue, with significantly reduced levels of systemic inflammation compared to wild type mice. F814 mice were also protected from HFD-induced bone loss and cartilage degeneration. Pharmacological inhibition of gp130-Y814/SFK in mice on HFD mirrored the effects observed in F814 mice on HFD; furthermore, this pharmacological treatment also demonstrated a marked increase in physical activity levels and protective effects against inflammation-associated suppression of neurogenesis in the brain tissue compared to the control group. These findings suggest that selective inhibition of SFK signaling downstream of gp130 receptor represents a promising strategy to alleviate systemic chronic inflammation. Increased degenerative changes and tissue senescence are inevitable in obese and aged organisms, but we demonstrated that the systemic response and inflammation-associated multi-morbidity can be therapeutically mitigated.

cell biology↗

Spatiotemporal development of growth and death zones in expanding bacterial colonies driven by emergent nutrient dynamics

Bacterial colony growth on hard agar is commonplace in microbiology; yet, what occurs inside a growing colony is complex even in the simplest cases. Robust colony expansion kinetics featuring a linear radial growth and a saturating vertical growth indicates a common developmental program which is elucidated here for Escherichia coli cells using a combination of modeling and experiments. Radial colony expansion is found to be limited by mechanical factors rather than nutrients as commonly assumed. In contrast, vertical expansion is limited by glucose depletion inside the colony, an effect compounded by reduced growth yield due to anaerobiosis. Carbon starvation in the colony interior results in substantial cell death within 1-2 days, with a distinct death zone that expands with the growing colony. Overall, the development of simple colonies lacking EPS production and differentiation is dictated by an interplay of mechanical constraints and emergent nutrient gradients arising from obligatory metabolic processes.

microbiology↗

SCFFBXW11 complex targets interleukin-17 receptor A for ubiquitin-proteasome-mediated degradation.

Interleukin-17 (IL-17) is a pro-inflammatory cytokine, participating in innate and adaptive immune responses, that plays an important role in host defense, autoimmune diseases, tissue regeneration, metabolic regulation, and tumor progression. Post-translational modifications (PTMs) are crucial for protein function, stability, cellular localization, cellular transduction, and cell death. However, PTMs of IL-17 receptor A (IL-17RA) have not been investigated. Here, we showed that human IL-17RA was targeted by F-box and WD repeats domain containing 11 (FBXW11) for ubiquitination, followed by proteasome-mediated degradation. We used bioinformatics tools and biochemical techniques to determine that FBXW11 ubiquitinated IL-17RA through a lysine 27-linked polyubiquitin chain, targeting IL-17RA for proteasomal degradation. Domain 665-804 of IL-17RA was critical for interaction with FBXW11 and subsequent ubiquitination. Our study demonstrates that FBXW11 regulates IL-17 signaling pathways at IL-17RA level.

biochemistry↗

Establishment of the trans-resveratrol-induced mouse pulmonary fibrosis model and its comparison with the bleomycin-induced model

Pulmonary fibrosis (PF) is a progressive, fatal disease, and its pathogenic mechanism has not yet been identified. The bleomycin (BLM)-induced animal model has several shortcomings that cannot be overcome. We accidentally found that the continuous oral administration of trans-resveratrol (TR) at levels above the prescribed dose can induce PF within a certain period of time, and this model can be successfully replicated in mice, as indicated by the hydroxyproline (HYP) test and pathological analysis. The TR model requires no anesthesia or surgery and thus causes less damage to mice than the BLM model. The progress of fibrosis in the TR model was slow but progressed steadily compared with the BLM model, and the TR model was more comparable to human PF. Although the pathogenesis is not understood, the TR-induced PF model indicated that there may be a close relationship between PF and tumors and antitumor drugs, which requires further exploration.

pharmacology and toxicology↗