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PubMed2026

Enhanced Production of Recombinant Thermophilic Xylanase X11P in Ogataea polymorpha via In-Silico Signal Peptide Discovery and Fed-Batch Fermentation.

Efficient secretion of heterologous proteins is essential for advancing yeast-based bioprocesses, yet signal peptide (SP) optimization in the thermotolerant methylotrophic yeast Ogataea polymorpha remains limited. This study integrates in-silico SP discovery, experimental validation, and bioprocess engineering to enhance secretion of the thermophilic xylanase X11P under sucrose-inducible expression. Genome-wide screening of 5184 O. polymorpha proteins using SignalP, Phobius, DeepLoc, WoLF PSORT, and ProP identified 11 high-confidence SP candidates. Comparative analysis with Komagataella phaffii endogenous proteins guided selection of seven SPs for experimental evaluation. Among these, the novel O. polymorpha α-mating factor-like peptide FUN_005010 exhibited strong secretion-promoting activity, with its prepro-sequence yielding the highest extracellular xylanase levels and outperforming the classical Saccharomyces cerevisiae α-MF. To evaluate industrial applicability, sucrose-based fermentation strategies were systematically optimized in a 5-L bioreactor. Controlled sucrose feeding and balanced C/N ratios were found to be critical for maximizing maltase (MAL) promoter-driven expression. A stepwise increasing sucrose feed combined with induction at 30°C enabled X11P titers up to 770 U/mL, representing a 15-fold improvement over shake-flask cultures. This work demonstrates that the combination of SP evaluation and optimized sucrose-inducible fed-batch operation significantly enhances X11P production in O. polymorpha. The identified FUN_005010-prepro SP and the refined process framework provide valuable tools for developing O. polymorpha as a high-performance industrial expression platform.

Fermentation↗

PubMed2026

A two-factor authentication mechanism licenses pilins for pilus assembly in gram-positive bacteria.

Gram-positive bacteria display virulence-associated pili that facilitate adhesion and biofilm formation. These pili are covalently polymerized by class C sortase enzymes, which selectively recognize their cognate pilin substrates amid numerous cell wall sorting signal (CWSS)-bearing proteins. The molecular basis for this stringent substrate specificity has remained unclear. Here, we develop a rapid, quantitative fluorescence-activated cell sorting assay to monitor pilus assembly in Corynebacterium diphtheriae, enabling high-throughput analysis of SpaA pilin and SrtA sortase variants. Using this platform, together with molecular modeling and dynamics simulations, we show that SrtA engages nearly the entire SpaA CWSS to form a membrane-embedded complex that incorporates not only the LPXTG motif but also its connector and transmembrane helix elements. Formation of this interface displaces an inhibitory active-site lid and activates the enzyme to load the pilin substrate. Systematic CWSS swapping experiments and deep mutational scanning further support this model, demonstrating that noncognate pilins are excluded because they fail to form the required interface. Conversely, SrtA variants with an artificially unlatched lid bypass the need for this interface, indicating that membrane-driven complex formation is important for substrate licensing. Together, these findings define a "two-factor authentication" mechanism for pilus assembly in gram-positive bacteria: class C sortases first verify pilin identity by forming a membrane-embedded interface that activates the enzyme, then they recognize the LPXTG motif to initiate loading and crosslinking. This work provides a unified molecular framework for selective pilin incorporation in gram-positive bacteria and identifies potential vulnerabilities in the licensing machinery that may be exploited therapeutically.

Fimbriae, Bacterial↗

PubMed2025

Multi-Omics Platforms Reveal Synergistic Intestinal Toxicity in Tilapia from Acute Co-Exposure to Polystyrene Microplastics, Sulfamethoxazole, and BDE153.

Polystyrene microplastic (MP) and its co-existing contaminants may exert different toxic effects on its surrounding aquatic organisms. In order to detect the intestinal harmful responses, tilapia were subjected to exposure with 75 nm of MPs, 100 ng·L-1 of sulfamethoxazole (SMZ), 5 ng·L-1 of BDE153, and combinations thereof over periods of 2, 4, and 8 days. Enzymatic assays, transcriptomics, proteomics, and metabolomics were employed to evaluate intestinal histopathological effects. Results showed that significant reductions were observed in ATP, ROS, SOD, EROD, lipid metabolism-related enzymes, pro-inflammatory cytokines (TNFα and IL-1β), and apoptosis marker caspase 3 across all groups at day 8. Histological evaluation revealed diminished goblet cell density, with distinct vacuole formation in the BDE153+MPs group. KEGG pathway analysis highlighted disruptions in endocytosis, MAPK signaling, phagosome formation, and actin cytoskeleton regulation. Proteomic findings indicated notable enrichment in endocytosis (decreased sorting nexin-2; increased Si:dkey-13a21.4), MAPK/PPAR signaling, protein processing in the endoplasmic reticulum (Sec61 subunit gamma), and cytoskeletal modulation (reduced fibronectin; elevated activation peptide fragment 1), with or without SMZ and BDE153. Metabolomic profiling showed significant alterations in ABC transporters, aminoacyl-tRNA biosynthesis, protein digestion and absorption, and linoleic acid metabolism. In summary, these findings suggest that BDE153 and MPs synergistically exacerbate intestinal damage and gene/protein expression over time, while SMZ appears to exert an antagonistic, mitigating effect.

Animals↗

PubMed2026

Extracellular Vesicles From Glioblastoma Cells Reflect 2D vs. 3D Culture Adaptation and Resistance to Temozolomide.

Glioblastoma (GBM) is an aggressive brain tumor marked by extensive heterogeneity, resistance to therapy, and dismal prognosis. Extracellular vesicles (EVs) have emerged as key players in GBM biology, mediating intercellular communication and therapy adaptation. However, the exact functions and molecular impact of EVs in GBM remain incompletely understood. In this study, we performed a comparative proteomic analysis of U87MG GBM cells grown in two-dimensional (2D) monolayers and three-dimensional (3D) spheroids following temozolomide (TMZ) treatment, alongside characterization of EVs derived from both culture systems. 3D-spheroids secreted more EVs of smaller size and exhibited a more TMZ-resistant, stem-like proteome under TMZ-induced genotoxic stress. In contrast, 2D cell cultures demonstrated greater proteome remodeling, with EVs enriched in protein families involved in DNA repair, oxidative stress adaptation, and methylation processes. Notably, several methyltransferases were decreased intracellularly but selectively retained in EVs, suggesting active sorting to influence the tumor microenvironment or modulate epigenetic states in recipient cells. EVs also carried adhesion molecules and signaling proteins linked to migration, invasion, and Wnt pathway activation, as well as metabolic enzymes connecting serine metabolism and redox control to TMZ resistance. Mapping EV and cellular proteomes onto The Cancer Genome Atlas (TCGA) dataset identified prognostic protein families associated with either poor or favorable patient outcomes. Our data demonstrate that EV cargo composition mirrors TMZ-induced phenotypic adaptation and reveals molecular mechanisms underlying therapeutic resistance. These EV-associated signatures may serve as clinically actionable biomarkers for patient stratification and offer potential targets to overcome chemoresistance in GBM.

Humans↗

PubMed2025

Expanding the druggable zinc-finger proteome defines properties of drug-induced degradation.

Glutarimide analogs, such as thalidomide, redirect the E3 ubiquitin ligase CRL4CRBN to induce degradation of certain zinc finger (ZF) proteins. Although the core structural motif recognized by CRBN has been characterized, it does not fully explain substrate specificity. To explore the role of residues adjacent to this core motif, we constructed a comprehensive ZF reporter library of 9,097 reporters derived from 1,655 human ZF proteins and conducted a library-on-library screen with 29 glutarimide analogs to identify compounds that collectively degrade 38 ZF reporters. Cryo-electron microscopy and crystal structures of ZFs in complex with CRBN revealed the importance of interactions beyond the core ZF degron. We used systematic mutagenesis of ZFs and CRBN to identify modes of neosubstrate recruitment requiring distinct amino acids. Finally, we found subtle chemical variations in glutarimide analogs that alter target scope and selectivity, thus providing a roadmap for their rational design.

Humans↗

PubMed2024

N-Glycosylation Deficiency in Transgene α7 nAChR and RIC3 Expressing CHO Cells Without NACHO.

The human neuronal nicotinic acetylcholine receptor α7 (nAChR) is an important target implicated in diseases like Alzheimer's or Parkinson's, as well as a validated target for drug discovery. For α7 nAChR model systems, correct folding and ion influx functions are essential. Two chaperones, resistance to inhibitors of cholinesterase 3 (RIC3) and novel nAChR regulator (NACHO), enhance the assembly and function of α7 nAChR. This study investigates the consequence of NACHO absence on α7 nAChR expression and function. Therefore, the sequences of human α7 nAChR and human RIC3 were transduced in Chinese hamster ovary (CHO) cells. Protein expression and function of α7 nAChR were confirmed by Western blot and voltage clamp, respectively. Cellular viability was assessed by cell proliferation and lactate dehydrogenase assays. Intracellular and extracellular expression were determined by in/on-cell Western, compared with another nAChR subtype by novel cluster fluorescence-linked immunosorbent assay, and N-glycosylation efficiency was assessed by glycosylation digest. The transgene CHO cell line showed expected protein expression and function for α7 nAChR and cell viability was barely influenced by overexpression. While intracellular levels of α7 nAChR were as anticipated, plasma membrane insertion was low. The glycosylation digest revealed no appreciable N-glycosylation product. This study demonstrates a stable and functional cell line expressing α7 nAChR, whose protein expression, function, and viability are not affected by the absence of NACHO. The reduced plasma membrane insertion of α7 nAChR, combined with incorrect matured N-glycosylation at the Golgi apparatus, suggests a loss of recognition signal for lectin sorting.

Animals↗

PubMed2026

Genome-wide insights into the evolutionary and demographic history of the red alga Mazzaella laminarioides: Evidence for speciation with ancient migration along the southeast Pacific coast.

The mechanisms driving lineage divergence in red algae remain unexplored, despite the group's remarkable diversity and ancient evolutionary history. The red alga Mazzaella laminarioides, a Chilean intertidal species complex composed of three parapatric cryptic lineages (North, Center, South), offers a valuable system to evaluate these processes, as its life history combines severe dispersal limitation with a haploid-diploid cycle that may influence the emergence of reproductive barriers. We reconstructed its evolutionary history using whole-genome sequencing and nuclear genome assembly of representative individuals from each lineage. Phylogenomic analyses based on 1,507 single-copy orthologs recovered three deeply divergent lineages with limited nuclear discordance consistent with incomplete lineage sorting. For both splits, demographic modelling was most consistent with an Ancient Migration scenario, although support over strict isolation was moderate, suggesting that divergence may have begun with low asymmetric ancestral gene flow followed by subsequent loss of connectivity, demographic bottlenecks, and later population expansion. Coding sequence analyses revealed lineage-specific dN/dS heterogeneity; only one South-lineage locus passed FDR correction (metaxin-1, mitochondrial protein import), with two further South-lineage candidates in chlorophyll and heme biosynthesis falling below the FDR threshold. Together, these signals suggest that divergent selective pressures on energy acquisition may have contributed to divergence at the southern end of the distribution. These results add to the small but growing body of whole-genome data for red algae and, alongside recent macroalgal studies, suggest that ancestral connectivity could be a recurrent feature of lineage divergence even in marine organisms with extremely restricted dispersal.

Rhodophyta↗

PubMed2026

Synaptic Proteome Divergence in the Prefrontal Cortex of Tame and Aggressive Red Foxes (Vulpes vulpes).

The biological mechanisms behind aggressive and affiliative behaviors are difficult to pinpoint. In the Farm-Fox Experiment, conventional foxes were selectively bred since 1959 in two different directions, one for tame and another for aggressive response to humans. The distinct differences in social behavior of tame, aggressive, and conventional populations are genetically based and the three populations live in conditions that control for factors that could impact social reactions, such as environment and social experiences. Genomic and transcriptomic studies of genetic differences among the fox populations have highlighted genes involved in synaptic processes in the prefrontal cortex. To investigate how the synaptic mechanisms differ between the three fox populations, synaptosomes were isolated from prefrontal and premotor cortex extracts of sixteen female foxes. Tandem mass tags with liquid chromatography tandem mass spectrometry (LC-MS) were used to identify and quantify the relative abundance of the proteins. The results were sorted into protein groups and compared between populations using a limma analysis to determine proteins with differential expression (DE). In the tame versus aggressive comparison, 174 protein groups were found to be DE, while only five were found in the conventional versus aggressive comparison. Most DE protein groups had lower fold expression in the aggressive population compared to tame and aggressive populations. ADGRB2 was found to be the most DE protein group, with 11-fold higher expression in aggressive foxes than in tame foxes. ADGRB2 was previously shown to affect depression-like behavior in mice and is involved in the vascular endothelial growth factor signaling pathway, that is known to influence neurogenesis. Enrichment analyses on the DE protein groups found gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were enriched in the tame versus aggressive comparison, including multiple, highly enriched terms involving ribosome and translation. Local translation at synapses plays an important role in synaptic plasticity and, as a result, can profoundly influence behavior. This study highlighted potential mechanisms that could underly the behavioral differences between tame and aggressive foxes.

Journal Article↗

PubMed2025

Endogenous Retroelement Activation is Implicated in Interferon-α Production and Anti-Cyclic Citrullinated Peptide Autoantibody Generation in Early Rheumatoid Arthritis.

OBJECTIVE: Endogenous retroelements (EREs) stimulate type 1 interferon (IFN-I) production but have not been explored as potential interferonogenic triggers in rheumatoid arthritis (RA). We investigated ERE expression in early RA (eRA), a period in which IFN-I levels are increased. METHODS: ERE expression (long terminal repeat [LTR] 5, long interspersed nuclear element 1 [LINE-1], and short interspersed nuclear element [SINE]) in disease-modifying treatment-naïve eRA whole-blood and bulk synovial tissue samples was examined by reverse transcription-polymerase chain reaction and NanoString alongside IFN-α activity. Circulating lymphocyte subsets, including B cell subsets, from patients with eRA and early psoriatic arthritis (ePsA) were flow cytometrically sorted and similarly examined. Existing established RA and osteoarthritis (OA) synovial single-cell sequencing data were reinterrogated to identify repeat elements, and associations were explored. RESULTS: There was significant coexpression of all ERE classes and IFNA in eRA synovial tissue samples (n = 22, P < 0.0001) and significant positive associations between whole-blood LINE-1 expression (n = 56) and circulating IFN-α protein (P = 0.018) and anti-cyclic citrullinated peptide (anti-CCP) titers (P < 0.0001). ERE expression was highest in circulating eRA B cells, particularly naïve B cells compared with ePsA, with possible ERE regulation by SAM and HD Domain Containing Deoxynucleoside Triphosphate Triphosphohydrolase 1 transcription (SAMDH1) implicated and associations with IFNA again observed. Finally, in established RA synovium, LTRs, particularly human endogenous retroviral sequence K (HERVK), were most increased in RA compared with OA, in which, for all synovial subsets (monocytes, B cells, T cells, and fibroblasts), ERE expression associated with increased IFN-I signaling (P < 0.001). CONCLUSION: Peripheral blood and synovial ERE expression is examined for the first time in eRA, highlighting both a potential causal relationship between ERE and IFN-I production and an intriguing association with anti-CCP autoantibodies. This suggests EREs may contribute to RA pathophysiology with implications for future novel therapeutic strategies.

Humans↗

PubMed2026

Inflammatory cell death and monocyte dysfunction in VEXAS syndrome.

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a severe adult-onset autoinflammatory disease caused by somatic mutations in the UBA1 gene, disrupting cytoplasmic ubiquitin-activating enzyme E1 function in hematopoietic progenitors. Its pathogenesis remains poorly understood, particularly the mechanisms by which UBA1 mutations disrupt myeloid cell function in the context of inflammatory stimuli. Here, we combine a genetically engineered THP-1 monocytic model with ex vivo analyses of blood and tissue samples from patients with VEXAS syndrome to investigate the consequences of the canonical UBA1M41V mutation. We show that UBA1-mutated monocytes exhibit tumor necrosis factor α (TNF-α)-induced cell death, characterized by receptor-interacting serine/threonine-protein kinase 1 (RIPK1) phosphorylation, and mixed lineage kinase domain-like- and caspase-8-mediated cell death. Importantly, we extend these findings to patient-derived CD14+ sorted cells, confirming that these cells undergo aberrant apoptotic and necroptotic cell death. Mechanistically, activation of these cell death pathways appears to be promoted by defective NF-κB-dependent transcriptional responses and reduced cFLIP(L) expression following TNF-α stimulation. UBA1-mutated monocytes also display blunted cytokine responses to Toll-like receptor (TLR) agonists despite preserved TLR expression, linked to an impaired NF-κB response. UBA1M41V-derived macrophages exhibit a proinflammatory transcriptional profile with increased chemokine secretion that promotes monocyte recruitment. In addition, these UBA1-mutated macrophages display impaired efferocytosis due to lysosomal dysfunction. Together, these findings reveal a pathogenic axis in VEXAS syndrome linking UBA1 loss of function and defective ubiquitination to RIPK1-mediated inflammatory cell death, impaired antimicrobial signaling, and defective resolution mechanisms. Our study provides novel mechanistic insights into the myeloid dysfunction underlying inflammation and cytopenia in VEXAS syndrome and supports the therapeutic targeting of inflammatory cell death pathways.

Humans↗