生物学最新文献

Porcine deltacoronavirus (PDCoV) is an emerging enteric pathogen that poses a significant threat to the global swine industry and carries a potential public health risk. The development of neutralizing monoclonal antibodies (mAbs) is crucial for preventing and controlling PDCoV. However, research on neutralizing linear epitopes within the PDCoV receptor-binding domain (RBD) and the establishment of serological assays based on such mAbs remains limited. In this study, we generated two neutralizing mAbs, 1C12 and 3A11, targeting the PDCoV RBD. Epitope mapping revealed that 1C12 recognizes a linear epitope (³¹⁶DFGEARLD³²³), whereas 3A11 binds to a conformational epitope. Further residue analysis identified Arg321 as the most critical residue for binding to 1C12. Additionally, the integrity of the entire ³²¹RLD³²³ motif was found to be indispensable for the conformational recognition by mAb 3A11. Using these mAbs, we developed two blocking enzyme-linked immunosorbent assay (bELISA) methods (bELISA-1C12 and bELISA-3A11). Evaluation of 150 clinical samples demonstrated that bELISA-1C12 exhibited 93.3% concordance with a virus neutralization test (VNT), indicating higher diagnostic sensitivity than bELISA-3A11 (92.7%). A large-scale serosurvey of pig populations across ten Chinese provinces in 2025, conducted using bELISA-1C12, revealed a PDCoV seropositivity rate of 13.6%. Notably, when extending the serological screening to 21 additional animal species, we detected PDCoV antibodies in peafowl serum for the first time, suggesting possible exposure to the virus. This study identifies key antigenic epitopes on the PDCoV RBD and provides valuable tools for epidemiological surveillance and assessing the transmission risk of PDCoV.

Objectives: To investigate the role of the SIRT5-PRDX6 axis during the pathogenesis of sepsis-associated acute kidney injury (SA-AKI).

Methods: In vivo and in vitro sepsis models were established to evaluate oxidative stress and inflammatory responses. High-throughput proteomics analysis identified ferroptosis as a key mechanism underlying SA-AKI. The levels of HMOX1, NQO-1, GPX4, ACSL4, Fe²⁺, IL-1β, TNF-α, MDA, and GSH were measured. SIRT5 knockdown/overexpression experiments were performed in HK-2 cells, and SIRT5-deficient mice were used to explore its regulatory role. Co-immunoprecipitation (Co-IP) and site-directed mutagenesis verified SIRT5-PRDX6 interaction and desuccinylation sites.

Results: Ferroptosis was critical in SA-AKI progression. In LPS-induced HK-2 cells, HMOX1, NQO-1, ACSL4, Fe²⁺, IL-1β, TNF-α, and MDA were significantly increased, whereas GSH and GPX4 were downregulated. Treatment with ferrostatin-1 (Fer-1) attenuated ferroptosis and oxidative damage. SIRT5 decreased in a time-dependent manner following LPS stimulation. SIRT5 knockdown exacerbated LPS-induced ferroptosis, whereas SIRT5 overexpression suppressed it. SIRT5 activation alleviated AKI in mice, whereas SIRT5 deficiency aggravated it. Mechanistically, SIRT5 desuccinylated PRDX6 at lysine 209, thereby inhibiting inflammatory and oxidative stress responses, attenuating ferroptosis, and ultimately ameliorating renal injury.

Conclusion: The SIRT5-PRDX6 axis regulates SA-AKI pathogenesis by modulating ferroptosis and represents a novel potential therapeutic target.

Objectives: Type III intermediate filaments, such as vimentin, GFAP, and desmin, are involved in cell mechanics, signaling, and stress responses, and are tightly regulated by posttranslational modifications (PTMs). The monomers of these proteins possess a single cysteine residue that plays a key role in network remodeling under oxidative stress. CoAlation is a PTM involving mixed disulfide bond formation between a protein thiol and the coenzyme A (CoA) thiol. Here we aim to investigate the potential CoAlation of vimentin, GFAP, and desmin, and its functional consequences.

Methods: CoAlation of type III intermediate filaments and its interplay with other oxidative modifications was assessed in vitro by gel assays and immunological detection, whereas its effect on vimentin filament assembly was evaluated by electron microscopy. In cells, CoAlation was evaluated by CoA immunofluorescence, proximity ligation assay, and/or immunoprecipitation.

Results: CoAlation of vimentin, GFAP, and desmin occurs in vitro and in cells, and is enhanced by oxidants. In the case of vimentin, CoA reciprocally influences other thiol group modifications in vitro, attenuating disulfide-mediated oligomerization and cysteine alkylation. Moreover, in vitro polymerization in the presence of CoA results in shorter vimentin filaments.

Conclusion: We show that vimentin, GFAP, and desmin are CoAlated at their single cysteine residues. Our results suggest that CoAlation may influence filament assembly and compete with other cysteine modifications. Moreover, given its reversibility, CoAlation could potentially play a protective role against more deleterious modifications, such as irreversible cysteine oxidation.

Objectives: Cr(VI) and DON are natural co-occurring pollutants in the environment. This study aimed to investigate the molecular mechanisms underlying oxidative damage to the intestinal barrier and intestinal epithelial cell (IECs) toxicity induced by Cr(VI) and DON.

Methods: The target genes and signaling pathways were predicted using the network toxicology method. This was verified through cell intervention experiments with Nrf2 activator TBHQ, NF-κB inhibitor PDTC, and NLRP3 inhibitor MCC950.

Results: Cr(VI) and/or DON aggravated inflammatory infiltration in the intestine, disrupted tight junction structures. Network toxicology revealed that ferroptosis and pyroptosis pathways are involved in regulating oxidative damage and barrier dysfunction in primary small IECs in broilers. Cr(VI) and/or DON induced oxidative stress and inhibited Nrf2 expression. They abnormally activated the NF-κB/NLRP3 pathway in IECs, thereby triggering ferroptosis and pyroptosis, and exacerbating oxidative damage to the intestinal barrier. Overexpression of Nrf2 and silencing of NLRP3/NF-κB could bidirectionally reverse oxidative stress, iron accumulation, inflammatory factor secretion and intestinal barrier dysfunction in IECs, inhibit the progression of ferroptosis and pyroptosis.

Conclusion: The cross-regulation of ferroptosis and pyroptosis mediated by the bidirectional imbalance of the Nrf2/NF‑κB/NLRP3 axis constitutes the core molecular mechanism underlying intestinal epithelial barrier dysfunction and oxidative damage induced by co-exposure to Cr(VI) and DON.

Programmed stop codon readthrough (SCR) is a form of genetic re-coding, in which a near-cognate tRNA base-pairs with a stop codon, leading to the translation of a C-terminally extended protein. Recent studies revealed that SCR represents an evolutionarily conserved, spatio-temporally controlled mechanism of posttranscriptional gene regulation that requires cis-regulatory elements as well as trans-acting factors. In this study, we characterized cis-regulatory elements controlling programmed SCR of the Drosophila POU3-family member drifter/ventral veins lacking (dfr/vvl). Using S2 cell-based luciferase assays, we show that stop codon identity and the +4 to +9 nucleotide sequence are required but not sufficient for dfr SCR regulation. Phylogenetic prediction identified an mRNA stem-loop in the 3' UTR, proximal to the readthrough UAG codon. Mutational analysis revealed that the distance from the stop codon as well as stem-loop stability, but not the underlying sequence identity, critically impact dfr SCR. Similarly, the mRNA stem-loop promoted SCR in an in vivo Drosophila model. We applied this information to refine computational prediction of SCR-associated mRNA stem-loops and show that these elements effectively promote SCR of heterologous mRNAs. These findings increase our understanding of SCR and the underlying regulatory mechanisms.

Background: Reactive oxygen species (ROS) regulate stem-cell function, but sustained exposure causes oxidative damage, mitochondrial dysfunction and exhaustion. Multilineage-differentiating Stress-Enduring (MUSE) cells, a rare SSEA-3⁺ MSC subset, tolerate ROS-rich environments, although the mechanisms remain unclear.

Methods: We compared MUSE, Non-MUSE (SSEA-3⁻) and MSCs after H₂O₂ exposure, assessing ROS clearance, mtDNA integrity, 8-oxo-dG, antioxidant and BER responses, mitochondrial morphology/function, mitophagy and biogenesis, with focus on the PGC-1α/NRF2 axis. Three independent biological replicates were analyzed by imaging, qPCR, flow cytometry and biochemical assays.

Results: MUSE cells showed greater resistance to oxidative stress than MSCs and Non-MUSE cells. After H₂O₂, they displayed lower ROS accumulation (~15-25%), preserved mtDNA integrity, reduced 8-oxo-dG, rapid induction of antioxidant and BER-related genes, and maintenance of mitochondrial morphology, membrane potential and respiratory activity. MUSE cells also showed enhanced mitophagy, with >2-fold increased LAMP1-MitoTracker colocalization and induction of PINK1/phospho-Ub-S65, together with increased biogenesis, including ~45% higher COX-I/SDHA ratio, TFAM induction and PGC-1α activation at 48 h.

Conclusion: MUSE cells coordinate antioxidant defense, DNA repair, mitophagy and biogenesis through a remove-and-replace program that preserves mitochondrial function during oxidative stress.

Objective: Subarachnoid hemorrhage (SAH) is associated with high mortality and poor outcomes, which are closely related to white matter injury (WMI). (-)-Epigallocatechin-3-gallate (EGCG) exerts neuroprotective effects by inhibiting oxidative stress-related ferroptosis in astrocytes and improving neurological function. However, the role and mechanism of EGCG in regulating reactive astrocytes (RAs) to alleviate WMI after SAH remain unclear.

Methods: A mouse model of SAH was used to evaluate the effects of EGCG-loaded nanoparticles (EGCG-NPs). Western blot, qPCR, and immunofluorescence were performed for biochemical analysis. Neurological function was assessed using neurological deficit scores and the Morris water maze test.

Results: Following SAH, HO-1-mediated iron accumulation and ROS production promoted A1/A2 reactive astrocyte polarization, resulting in myelination damage and aggravated WMI. Knockdown of S100A10 inhibited iron-dependent oxidative stress in RAs and attenuated WMI. EGCG-NPs significantly suppressed HO-1/S100A10-mediated iron overload and oxidative stress in both A1 and A2 RAs, thereby alleviating WMI after SAH.

Conclusion: EGCG-NPs attenuate SAH-induced WMI by inhibiting the iron overload-activated HO-1/S100A10 axis in RAs, representing a promising therapeutic strategy.

We, the Editor and Publisher of Bioengineered have retracted the following article: Xiaocui Liu, "Effects of Methyl Donors on L-Tryptophan Fermentation," Bioengineered, 10.1080/21655979.2021.1882821.This author became unresponsive after the posting of the author's accepted manuscript version of this article and has not responded to follow up emails for over one year. Since the author has not signed the copyright agreement, Bioengineered cannot proceed with final publication and must remove the accepted author manuscript version from the website.We have been informed in our decision-making by our policy on publishing ethics and integrityandthe COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as "Retracted".

Background: Oxidative stress-induced liver injury can progress to severe hepatic conditions. Polysaccharides are promising therapeutic agents, but the protective effects of Angelica dahurica polysaccharide (ADP) against this injury remain unclear.

Purpose: This study was conducted to elucidate ADP's protective effects and underlying molecular mechanisms in Ovariectomize/D-galactose (OVX/D-Gal) rats.

Methods: Fifty female OVX rats and ten sham-operated (SO) rats were randomly divided into six groups. Except SO group, rats were administered the corresponding doses of ADP and resveratrol respectively, and the model was established by 49-day daily subcutaneous D-Gal injection. Serum and liver samples were collected to examine the hepatic histopathological changes, oxidative stress-related biomarkers, inflammatory factors, and protein and gene expression levels.

Results: ADP reduced serum ALT and AST levels (P < 0.01) and improved liver histology. ADP increased SOD and GSH-Px activities , decreased MDA levels (P < 0.05). ADP also lowered pro-inflammatory cytokines levels, upregulated Nrf2, HO-1, and NQO-1 expression, promoted Bcl-2 and suppressed Bax and cleaved caspase-3 (P < 0.05).

Conclusions: ADP alleviated OVX/D-Gal-induced oxidative stress and liver injury by increasing antioxidant capacity, inhibiting apoptosis, attenuating inflammation, and activating Nrf2/HO-1/NQO-1 signaling pathway.

Hematodinium sp. is a parasitic dinoflagellate that infects and causes disease in a large fraction of decapod crustaceans in the Northern Hemisphere. The shore crab Carcinus maenas is susceptible to this parasite in its native range of European coastlines and along its invasive fronts. The parasite enters the host from the surrounding water, and fueled by the hemolymph (blood) resources, proliferates until host tissues are overrun. To improve our knowledge of the shore crab-Hematodinium pathosystem, we profiled the hemolymph microbiome of control and Hematodinium-positive crabs with low (early clinical) and high (late clinical) parasite levels through bacterial 16S rRNA V3-V4 meta-barcoding (n = 64). Concurrently, we assessed hemolymph condition through quantification of circulating hemocytes (immune cells) and bacterial colony forming units. Progression of Hematodinium sp. infection coincided with gradual changes in bacterial community composition. These changes were driven by shifts in relative abundances of specific taxa, e.g. Corynebacterium, Flavobacterium. Furthermore, alterations in bacterial communities were accompanied by marked shifts in metabolic signatures from stress and virulence dominated (including biofilm formation) to catabolism, peptide transport, and tissue putrefaction at the terminal stage of parasitemia. We present the first account of microbiome dynamics in healthy shore crabs and those overcome by Hematodinium sp. Our experiments reveal a clear link between bacterial community structure-function and the advancing disease state.