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PubMed2024

Mannose receptor (MRC1) mediates uptake of dextran in macrophages via receptor-mediated endocytosis.

UNLABELLED: Macrophages maintain surveillance of their environment using receptor-mediated endocytosis and pinocytosis. Receptor-mediated endocytosis allows macrophages to recognize and internalize specific ligands whereas macropinocytosis non-selectively internalizes extracellular fluids and solutes. Here, CRISPR/Cas9 whole-genome screens were used to identify genes regulating constitutive and growth factor-stimulated dextran uptake in murine bone-marrow derived macrophages (BMDM). The endocytic mannose receptor c-type 1 ( Mrc1 , also known as CD206) was a top hit in the screen. Targeted gene disruptions of Mrc1 reduced dextran uptake but had little effect on uptake of Lucifer yellow, a fluid-phase marker. Other screen hits also differentially affected the uptake of dextran and Lucifer yellow, indicating the solutes are internalized by different mechanisms. We further deduced that BMDMs take up dextran via MRC1-mediated endocytosis by showing that competition with mannan, a ligand of MRC1, as well as treatment with Dyngo-4a, a dynamin inhibitor, reduced dextran uptake. Finally, we observed that IL4-treated BMDM internalize more dextran than untreated BMDM by upregulating MRC1 expression. These results demonstrate that dextran is not an effective marker for the bulk uptake of fluids and solutes by macropinocytosis since it is internalized by both macropinocytosis and receptor-mediated endocytosis in cells expressing MRC1. This report identifies numerous genes that regulate dextran internalization in primary murine macrophages and predicts cellular pathways and processes regulating MRC1. This work lays the groundwork for identifying specific genes and regulatory networks that regulate MRC1 expression and MRC1-mediated endocytosis in macrophages. SIGNIFICANCE STATEMENT: Macrophages constantly survey and clear tissues by specifically and non-specifically internalizing debris and solutes. However, the molecular mechanisms and modes of regulation of these endocytic and macropinocytic processes are not well understood. Here, CRISPR/Cas9 whole genome screens were used to identify genes regulating uptake of dextran, a sugar polymer that is frequently used as a marker macropinocytosis, and compared with Lucifer yellow, a fluorescent dye with no known receptors. The authors identified the mannose receptor as well as other proteins regulating expression of the mannose receptor as top hits in the screen. Targeted disruption of Mrc1 , the gene that encodes mannose receptor, greatly diminished dextran uptake but had no effect on cellular uptake of Lucifer yellow. Furthermore, exposure to the cytokine IL4 upregulated mannose receptor expression on the cell surface and increased uptake of dextran with little effect on Lucifer yellow uptake. Studies seeking to understand regulation of macropinocytosis in macrophages will be confounded by the use of dextran as a fluid-phase marker. MRC1 is a marker of alternatively activated/anti-inflammatory macrophages and is a potential target for delivery of therapeutics to macrophages. This work provides the basis for mechanistic underpinning of how MRC1 contributes to the receptor-mediated uptake of carbohydrates and glycoproteins from the tissue milieu and distinguishes genes regulating receptor-mediated endocytosis from those regulating the bona fide fluid-phase uptake of fluids and solutes by macropinocytosis.

Journal Article↗

PubMed2025

The Streptococcus pyogenes mannose phosphotransferase system (Man-PTS) influences antimicrobial activity and niche-specific nasopharyngeal infection.

Streptococcus pyogenes is a human-adapted pathogen that can cause multiple diseases, including pharyngitis and skin infections. Although this bacterium produces many virulence factors, how S. pyogenes competes with the host microbiota is not well understood. Here, we detected antimicrobial activity from S. pyogenes MGAS8232 that prevented the growth of Micrococcus luteus. This activity was produced when cells were grown in 5% CO2 in M17 media supplemented with galactose; however, the addition of alternative sugars coupled with genome sequencing experiments revealed that the antimicrobial phenotype was not related to classical bacteriocins. To further determine genes involved in the production of this activity, a transposon mutant library in S. pyogenes MGAS8232 identified the mannose phosphotransferase system (Man-PTS), a major sugar transporter, as important for the antimicrobial phenotype. Loss-of-function transposon mutants linked to the antimicrobial activity were identified to also be involved in alternative sugar utilization, and additionally, the Man-PTS was further identified from an inadvertent secondary mutation in a bacteriocin operon mutant. Sugar utilization in the Man-PTS mutants demonstrated that galactose, mannose, and N-acetylglucosamine utilization was impaired. RNA-seq experiments in high and low glucose concentrations further characterized the Man-PTS as a glucose transporter; however, transcriptional regulators or virulence factors were not affected with the loss of the Man-PTS. Deletion of Man-PTS demonstrated defects in a mouse model of nasopharyngeal infection but not skin infection. This work suggests that the ability of S. pyogenes to utilize alternative sugars presented by glycans may play a role in acute infection and interactions with the endogenous microbial population existing in the nasopharynx.IMPORTANCEStreptococcus pyogenes is responsible for over 500,000 deaths per year primarily due to invasive infections and post-infection sequelae, although the most common manifestations include pharyngitis and impetigo. S. pyogenes can adapt to its environment through alternative sugar metabolism. Here, we identified an antimicrobial phenotype that was not bacteriocin-related but a by-product of alternative sugar metabolism. The mannose phosphotransferase system was involved in the production of the antimicrobial and was also important for S. pyogenes to utilize alternative sugars and establish nasopharyngeal infection but not skin infection. Overall, this study identified potential strategies used by S. pyogenes for interactions with the endogenous microbiota and further elucidated the importance of sugar metabolism in acute upper respiratory tract infection.

Streptococcus pyogenes↗

PubMed2026

The novel transcriptional activator Bhr1 combining NTPase and Zn(II)2Cys6 DNA-binding domains controls (hemi-)cellulase response to mannose-rich substrates in the white-rot fungus Dichomitus squalens.

The regulatory landscape responsible for lignocellulose degradation in white-rot basidiomycete fungi remains largely unexplored. In this study, we characterize a novel transcriptional activator, Bhr1, in the white-rot fungus Dichomitus squalens. Bhr1 exhibits an unusual domain architecture that combines a septin-like P-loop NTPase fold with Zn(II)2Cys6 DNA-binding domains and plays a critical role in activating (hemi-)cellulase enzyme production when D. squalens is exposed to mannose-rich substrates. Using CRISPR/Cas9-mediated gene editing, we generated a bhr1 disruption mutant that displayed distinct phenotypes and enzyme activity profiles on mannose and guar gum compared to the wild type. RNA sequencing data indicate that Bhr1 induces specific (hemi-)cellulase-encoding genes without altering the expression of genes encoding sugar transporters or sugar metabolic enzymes. Phylogenetic analyses show that Bhr1 is basidiomycete specific and largely restricted to saprotrophic and plant-associated Agaricomycetes fungi. Based on the domain architecture of Bhr1 and the effects of its disruption in D. squalens, our findings reveal a lineage-specific regulatory innovation in basidiomycetes that is distinct from those described in ascomycetes. Elucidating the function and evolutionary conservation of Bhr1 advances our understanding of lignocellulose degradation at the molecular level in basidiomycete fungi and may inform studies of their ecological adaptation and the development of biotechnological applications.IMPORTANCEUnderstanding the transcriptional regulatory mechanisms in white-rot fungi, such as Dichomitus squalens, is crucial for advancing our knowledge of lignocellulose degradation. This study identifies D. squalens Bhr1 as a key regulator of (hemi-)cellulase production on mannose-rich substrates and further distinguishes basidiomycete transcription factors involved in plant biomass degradation from their ascomycete counterparts. Our findings highlight the significance of lineage-specific regulators in facilitating adaptive enzyme production for efficient biomass utilization, which is critical to carbon cycling in terrestrial ecosystems. This work establishes a foundation for exploring novel regulatory strategies among wood-degrading fungi, potentially enabling targeted strain engineering in biotechnological applications.

Mannose↗

PubMed2024

A proteomics-based survey reveals thrombospondin-4 as a ligand regulated by the mannose receptor in the injured lung.

Receptor-mediated cellular uptake of specific ligands constitutes an important step in the dynamic regulation of individual protein levels in extracellular fluids. With a focus on the inflammatory lung, we here performed a proteomics-based search for novel ligands regulated by the mannose receptor (MR), a macrophage-expressed endocytic receptor. WT and MR-deficient mice were exposed to lipopolysaccharide, after which the protein content in their lung epithelial lining fluid was compared by tandem mass tag-based mass spectrometry. More than 1200 proteins were identified in the epithelial lining fluid using this unbiased approach, but only six showed a statistically different abundance. Among these, an unexpected potential new ligand, thrombospondin-4 (TSP-4), displayed a striking 17-fold increased abundance in the MR-deficient mice. Experiments using exogenous addition of TSP-4 to MR-transfected CHO cells or MR-positive alveolar macrophages confirmed that TSP-4 is a ligand for MR-dependent endocytosis. Similar studies revealed that the molecular interaction with TSP-4 depends on both the lectin activity and the fibronectin type-II domain of MR and that a closely related member of the TSP family, TSP-5, is also efficiently internalized by the receptor. This was unlike the other members of this protein family, including TSPs -1 and -2, which are ligands for a close MR homologue known as urokinase plasminogen activator receptor-associated protein. Our study shows that MR takes part in the regulation of TSP-4, an important inflammatory component in the injured lung, and that two closely related endocytic receptors, expressed on different cell types, undertake the selective endocytosis of distinct members of the TSP family.

Animals↗

PubMed2024

Mannose receptor (MRC1) mediates uptake of dextran by bone marrow-derived macrophages.

Macrophages survey their environment using receptor-mediated endocytosis and pinocytosis. Receptor-mediated endocytosis allows internalization of specific ligands, whereas pinocytosis nonselectively internalizes extracellular fluids and solutes. CRISPR/Cas9 whole-genome screens were used to identify genes regulating constitutive and growth factor-stimulated dextran uptake in murine bone marrow-derived macrophages (BMDM). The mannose receptor c-type 1 (MRC1/CD206) was a top hit in the screen. Targeted gene disruptions of Mrc1 reduced dextran uptake but had little effect on fluid-phase uptake of Lucifer yellow. Other screen hits also differentially affected the uptake of dextran and Lucifer yellow, indicating internalization by separate mechanisms. Visualization of dextran and Lucifer yellow uptake by microscopy showed enrichment of dextran in small puncta, which was inhibitable by mannan, a ligand of MRC1. In contrast, Lucifer yellow predominantly was internalized in larger macropinosomes. In addition, IL4-treated BMDMs internalized more dextran than untreated BMDM correlating with increased MRC1 expression. Therefore, dextran is not an effective marker for pinocytosis in BMDMs since it is internalized by receptor-mediated process. Numerous genes that regulate dextran internalization in primary murine macrophages were identified in the whole-genome screens, which can inform understanding of the regulation of MRC1 expression and MRC1-mediated uptake in macrophages.

Animals↗

PubMed2026

Association between 1400 blood metabolites and the risk of ankylosing spondylitis: A 2-stage, 2-sample Mendelian randomization study.

Human blood metabolites have been closely linked to ankylosing spondylitis (AS) in observational studies, yet direct causal evidence remains limited. This study aims to use Mendelian randomization (MR) to pinpoint causal metabolites associated with AS and to predict potential side effects of metabolite interventions. Genetic instruments for exposure were sourced from a genome-wide association study of 1400 blood metabolites, while genome-wide association study data for AS outcomes were derived from the FinnGen cohort. The primary MR analysis was conducted using the inverse variance weighted method. Supplemental analyses were conducted using weighted median, MR-Egger, simple mode, and weighted mode methods, while sensitivity analyses were performed to evaluate heterogeneity and pleiotropy. A replication analysis using an additional the UK Biobank cohort was also performed to determine metabolites associated with AS. The Steiger test and linkage disequilibrium score regression were used to further strengthen causal inference. Lastly, a phenome-wide Mendelian randomization analysis was performed to investigate the potential on-target side effects of metabolite interventions. After comprehensive analyses, 3 metabolites (the 2'-deoxyuridine levels, the hate to mannose ratio, and the Uridine to 2'-deoxyuridine ratio) were identified as being genetically associated with AS. The phenome-wide Mendelian randomization analysis revealed that the hate to mannose ratio might have deleterious effects on 4 other diseases, while no significant associations were found for the 2'-deoxyuridine levels or the uridine to 2'-deoxyuridine ratio with other diseases. This systematic MR analysis unveiled the potential role of the 2'-deoxyuridine levels, hate to mannose ratio and uridine to 2'-deoxyuridine ratio as the causal mediator in the development of AS. Considering the advantages and disadvantages, 2'-deoxyuridine appears as the most promising prospective therapeutic target for the prevention of AS.

Humans↗

PubMed2026

Glycaemic burden disrupts innate immunity in TB by modulating CD206 expression and macrophage antimicrobial responses.

Tuberculosis (TB) and diabetes mellitus (DM) represent a growing dual global health burden, with chronic hyperglycaemia recognized as a major modifier of host immunity against Mycobacterium tuberculosis (Mtb). Macrophages, central to pathogen recognition, phagocytosis, antigen presentation, and intracellular killing, may be particularly vulnerable to diabetic metabolic dysregulation. This study evaluated phenotypic and functional macrophage alterations in individuals with pulmonary TB, type 2 DM, TB-DM comorbidity, and healthy controls. Surface receptor expression was analysed by multicolour flow cytometry, while phagocytosis and intracellular bacterial clearance were assessed using FITC-labelled Mtb assays and colony-forming unit enumeration. Hyperglycaemia was associated with reduced CD11b, MARCO, and TLR2 expression alongside upregulation of the mannose receptor CD206, which correlated positively with HbA1c levels, indicating a shift toward a permissive M2-like phenotype. Phagocytic uptake of Mtb was significantly impaired and inversely correlated with HbA1c. Antigen-presenting capacity was selectively compromised, with reduced CD80 and CD86 expression in DM and TB-DM groups, while HLA-DR remained unchanged. Intracellular Mtb killing was markedly diminished in diabetic macrophages. These findings demonstrate that chronic hyperglycaemia profoundly disrupts macrophage innate immunity, contributing to increased TB susceptibility and poor infection control in diabetic populations.

Humans↗

PubMed2025

Sex-dependent influence of LMAN1 on allergen-induced airway hyperresponsiveness.

Allergic asthma is a chronic inflammatory disease of the airways characterized by a type 2-high adaptive immune response towards common aeroantigens such as dust mite, pollen, and animal dander. Despite the advances made toward translation of various biologics into the clinic, the limited efficacy of these therapies in certain populations, combined with the ineligibility of some patients for treatment (clinically or economically), have led to the continued need for the development of more widely effective allergic asthma therapies. Our lab previously identified lectin mannose-binding 1 (LMAN1) as a novel receptor for house dust mite (HDM) and showed that in vitro, LMAN1 downregulated inflammatory NF-κB signaling in DCs in response to HDM. In this follow-up work, we investigated the in vivo relevance of LMAN1 by subjecting LMAN1 knockout (KO) mice and wild type (WT) littermate controls to a model of HDM-induced allergic asthma. Surprisingly, we discovered that loss of LMAN1 led to opposing effects on airway hyperresponsiveness (AHR), which were dependent on the sex of the mice. HDM-treated female LMAN1 KO mice showed increased AHR, while HDM-treated male KO mice showed decreased AHR, compared with their WT counterparts. We further identified the features of HDM-induced asthma which may account for the gender-biased effects of LMAN1 on lung function. This work not only highlights the complexity of the loss of LMAN1 in vivo but also suggests that such sex-dependent responses should be taken into consideration when pursuing LMAN1 as a therapeutic target for treatment of allergic asthma.

Animals↗

PubMed2025

Pitavastatin, Procollagen Pathways, and Plaque Stabilization in Patients With HIV: A Secondary Analysis of the REPRIEVE Randomized Clinical Trial.

IMPORTANCE: In a mechanistic substudy of the Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) randomized clinical trial, pitavastatin reduced noncalcified plaque (NCP) volume, but specific protein and gene pathways contributing to changes in coronary plaque remain unknown. OBJECTIVE: To use targeted discovery proteomics and transcriptomics approaches to interrogate biological pathways beyond low-density lipoprotein cholesterol (LDL-C), relating statin outcomes to reduce NCP volume and promote plaque stabilization among people with HIV (PWH). DESIGN, SETTING, AND PARTICIPANTS: This was a post hoc analysis of the double-blind, placebo-controlled, REPRIEVE randomized clinical trial. Participants underwent coronary computed tomography angiography (CTA), plasma protein analysis, and transcriptomic analysis at baseline and 2-year follow-up. The trial enrolled PWH from April 2015 to February 2018 at 31 US research sites. PWH without known cardiovascular diseases taking antiretroviral therapy and with low to moderate 10-year cardiovascular risk were eligible. Data analyses were conducted from October 2023 to February 2024. INTERVENTION: Oral pitavastatin calcium, 4 mg per day. MAIN OUTCOMES AND MEASURES: Relative change in plasma proteomics, transcriptomics, and noncalcified plaque volume among those receiving treatment vs placebo. RESULTS: Among 558 individuals (mean [SD] age, 51 [6] years; 455 male [82%]) included in the proteomics assessment, 272 (48.7%) received pitavastatin and 286 (51.3%) received placebo. After adjusting for false discovery rates, pitavastatin increased abundance of procollagen C-endopeptidase enhancer 1 (PCOLCE), neuropilin 1 (NRP-1), major histocompatibility complex class I polypeptide-related sequence A (MIC-A) and B (MIC-B), and decreased abundance of tissue factor pathway inhibitor (TFPI), tumor necrosis factor ligand superfamily member 10 (TRAIL), angiopoietin-related protein 3 (ANGPTL3), and mannose-binding protein C (MBL2). Among these proteins, the association of pitavastatin with PCOLCE (a rate-limiting enzyme of collagen deposition) was greatest, with an effect size of 24.3% (95% CI, 18.0%-30.8%; P < .001). In a transcriptomic analysis, individual collagen genes and collagen gene sets showed increased expression. Among the 195 individuals with plaque at baseline (88 [45.1%] taking pitavastatin, 107 [54.9%] taking placebo), changes in NCP volume were most strongly associated with changes in PCOLCE (%change NCP volume/log2-fold change = -31.9%; 95% CI, -42.9% to -18.7%; P < .001), independent of changes in LDL-C level. Increases in PCOLCE related most strongly to change in the fibro-fatty (<130 Hounsfield units) component of NCP (%change fibro-fatty volume/log2-fold change = -38.5%; 95% CI, -58.1% to -9.7%; P = .01) with a directionally opposite, although nonsignificant, increase in calcified plaque (%change calcified volume/log2-fold change = 34.4%; 95% CI, -7.9% to 96.2%; P = .12). CONCLUSIONS AND RELEVANCE: Results of this secondary analysis of the REPRIEVE randomized clinical trial suggest that PCOLCE may be associated with the atherosclerotic plaque stabilization effects of statins by promoting collagen deposition in the extracellular matrix transforming vulnerable plaque phenotypes to more stable coronary lesions. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02344290.

Humans↗

PubMed2026

Transcriptomic responses of gill and intestinal tissues in Nile tilapia (Oreochromis niloticus) to bacterial infection following sequential nanoimmersion and hydrogel-based multivalent vaccination.

Bacterial pathogens, including Flavobacterium oreochromis, Aeromonas veronii, Streptococcus agalactiae, and Edwardsiella tarda, represent major infectious threats to Nile tilapia (Oreochromis niloticus). A multivalent vaccination strategy integrating cationic nanoemulsion immersion with oral hydrogel boosters was developed to investigate tissue-specific immune responses at the transcriptomic level. Gill tissues were collected following immersion challenge and intestinal tissues following intraperitoneal injection challenge, reflecting the physiologically relevant infection biology of each pathogen and the mechanistic rationale of each delivery platform. RNA sequencing (RNA-seq) generated high-quality datasets (mapping rate > 81.64%) with strong concordance to quantitative real-time PCR (qRT-PCR) validation (r = 0.83). Comparative transcriptomic analysis revealed distinct yet complementary immune signatures between tissues. Gill transcriptomes were enriched in phagosome, focal adhesion, extracellular matrix-receptor interaction (ECM-receptor interaction), and cytokine-cytokine receptor interaction pathways, accompanied by increased expression of major histocompatibility complex class I/II (MHC class I/II), mannose receptor, αVβ3 integrin, and calnexin, indicating innate activation, enhanced phagocytic capacity, epithelial barrier reinforcement, and adaptive immune coordination. Intestinal transcriptomes showed predominant enrichment of adaptive immune pathways, including the intestinal immune network for immunoglobulin (Ig) production, Forkhead box O (FoxO) signaling, and mitogen-activated protein kinase (MAPK) signaling, with increased expression of T-cell receptor (TCR), inducible T-cell co-stimulator ligand (ICOS-L), C-X-C chemokine receptor type 4 (CXCR4), and polymeric immunoglobulin receptor (pIgR), reflecting T and B cell coordination, lymphocyte trafficking, and mucosal immunoglobulin transport, alongside innate engagement through phagosome pathway enrichment. Shared upregulation of MHC class II, B-cell receptor (BCR) signaling, integrin alpha M (ITGAM), and immunoglobulin-associated components across both tissues suggests coordinated mucosal immune activation through a conserved immune module, warranting direct experimental validation. Collectively, these findings provide transcriptomic evidence that this vaccination strategy elicits an integrated, tissue-specialized immune response, advancing mechanistic understanding of gill and intestinal immunity in vaccine-induced protection of teleost fish.

Animals↗

PubMed2026

Genetic and biochemical screens identify MGAT1 as a druggable glycosyltransferase target in STK11-mutant lung cancer.

Checkpoint inhibitors are standard-of-care therapies for non-small cell lung cancer (NSCLC), but their efficacy is limited in tumors with STK11 mutations, highlighting the need for new therapeutic strategies. Here, we performed complementary in vivo and in vitro CRISPR-Cas9 functional genomic screens to identify genes whose loss restores sensitivity to anti-PD-1 therapy. We found that loss of MGAT1, a Golgi glycosyltransferase critical for the maturation of high-mannose N-glycans into hybrid and complex glycan structures, reversed resistance to anti-PD-1 treatment in syngeneic mouse tumor models harboring STK11 mutations. Parallel co-culture screens with antigen-matched CD8+ T cells further showed that disruption of N-glycosylation strongly sensitized tumor cells to T cell-mediated killing. Genetic rescue studies demonstrated that this immune-evasion phenotype depends on MGAT1 catalytic activity, supporting direct biochemical interrogation of the enzyme. Using purified human MGAT1 and a UDP-Glo™ glycosyltransferase assay, we established a tractable screening platform and performed a 500,000-compound biochemical high-throughput screen, identifying an initial hit (compound 1; IC50 = 197 μM). Subsequent medicinal chemistry optimization delivered progressively more potent analogs, including TNG-9333 (0.814 μM) and TNG-2673 (0.043 μM) and represented a >1000-fold improvement in biochemical potency from the starting hit. Crystal structures of human MGAT1 in apo, UDP-bound, UDP-GlcNAc-bound, and inhibitor-bound states, together with SPR and DSF analyses, revealed that this chemical series engages a previously unrecognized allosteric pocket and inhibits MGAT1 through a UDP-noncompetitive mechanism. Collectively, our work implicates N-glycosylation as a key mediator of immune evasion and establishes MGAT1 as a ligandable, structurally tractable target for small-molecule drug discovery.

CRISPR/Cas9 target discovery↗

PubMed2026

Unravelling the genomic potential of sponge-associated Streptomyces sp. BLC 17-3 from Indonesia for mannooligosaccharide production.

This research aims to show the promising capacity of Streptomyces sp. BLC 17-3 to produce high β-mannanase enzymes and generate mannooligosaccharide (MOS) such as mannobiose, mannotriose, mannotetraose and mannopentaose when exposed to mannan polymers. Streptomyces sp. BLC 17-3 was isolated from the sponge (Rhabdastrella globostellata) Put4 obtained from the marine waters of Putus Island in Bitung, North Sulawesi, Indonesia. The characterization results showed that the peak enzyme activity was achieved at 50 mM sodium acetate, 6.0 pH, and 60 °C temperature on the seventh day of production with a value of 155.77 ± 3.21 U/mL. The SDS-PAGE and zymograms also showed that the size of the enzyme molecule was approximately ±34.8-49.1 kDa. Moreover, whole-genome sequencing was conducted to identify the genetic basis of MOS-synthesizing capabilities in the selected strain, followed by functional annotation of genes encoding mannan degradation and associated functions. The results showed an 8,248,862 Mb complete draft genome of the strain which comprised 111 predicted gene models. Gene annotation also provided important information about the location and function of protein-encoding genes. A total of 6 mannan degradation-related genes encoding mannanase-related metabolism were identified and the three-dimensional structures were predicted using AlphaFold 3. This characterization and modeling further enhanced the bioprospecting and development of this strain which exhibited efficient mannose metabolism. The results showed Streptomyces sp. BLC 17-3 as a promising microorganism for the future bioproduction of MOS which were discovered to have the capability of serving as a potential prebiotic substance to enhance digestion and promote health.

Bioprospecting↗

PubMed2024

GRable Version 1.0: A Software Tool for Site-Specific Glycoform Analysis With Improved MS1-Based Glycopeptide Detection With Parallel Clustering and Confidence Evaluation With MS2 Information.

High-throughput intact glycopeptide analysis is crucial for elucidating the physiological and pathological status of the glycans attached to each glycoprotein. Mass spectrometry-based glycoproteomic methods are challenging because of the diversity and heterogeneity of glycan structures. Therefore, we developed an MS1-based site-specific glycoform analysis method named "Glycan heterogeneity-based Relational IDentification of Glycopeptide signals on Elution profile (Glyco-RIDGE)" for a more comprehensive analysis. This method detects glycopeptide signals as a cluster based on the mass and chromatographic properties of glycopeptides and then searches for each combination of core peptides and glycan compositions by matching their mass and retention time differences. Here, we developed a novel browser-based software named GRable for semi-automated Glyco-RIDGE analysis with significant improvements in glycopeptide detection algorithms, including "parallel clustering." This unique function improved the comprehensiveness of glycopeptide detection and allowed the analysis to focus on specific glycan structures, such as pauci-mannose. The other notable improvement is evaluating the "confidence level" of the GRable results, especially using MS2 information. This function facilitated reduced misassignment of the core peptide and glycan composition and improved the interpretation of the results. Additional improved points of the algorithms are "correction function" for accurate monoisotopic peak picking; one-to-one correspondence of clusters and core peptides even for multiply sialylated glycopeptides; and "inter-cluster analysis" function for understanding the reason for detected but unmatched clusters. The significance of these improvements was demonstrated using purified and crude glycoprotein samples, showing that GRable allowed site-specific glycoform analysis of intact sialylated glycoproteins on a large-scale and in-depth. Therefore, this software will help us analyze the status and changes in glycans to obtain biological and clinical insights into protein glycosylation by complementing the comprehensiveness of MS2-based glycoproteomics. GRable can be freely run online using a web browser via the GlyCosmos Portal (https://glycosmos.org/grable).

Glycopeptides↗

PubMed2026

Transcriptomic and metabolomic analyses revealed the action mechanism of nesfatin-1 gene on glucolipid metabolism during early development stage of largemouth bass.

Nesfatin-1 has biological roles including the suppression of food intake and the regulation of glucose and lipid metabolism. However, the information available regarding nesfatin-1 in the glycolipid metabolism in the early development stage of fish is still limited. In order to investigate the role of the nesfatin-1 gene in the early development stage of the largemouth bass (Micropterus salmoides), the nesfatin-1 gene was knocked down using siRNA interference technology. Then, we evaluated its mRNA expression levels, transcriptomes and metabolomes. The mRNA expression levels of nesfatin-1 gene were appreciably decreased at 48 h, 72 h and 96 h after injection of nesfatin-1 siRNA in the early development stage. The omics results revealed that knockdown of the nesfatin-1 gene induced 1833 differentially expressed genes (DEGs) and 2370 differentially expressed metabolites (DEMs). Bioinformatic analysis enriched the most affected molecular pathways (sphingolipid metabolism, fatty acid elongation, amino sugar and nucleotide sugar metabolism and biosynthesis of unsaturated fatty acids) and metabolic pathways (biosynthesis of unsaturated fatty acids, sphingolipid metabolism and amino sugar and nucleotide sugar metabolism) in early development stage of largemouth bass. In amino sugar and nucleotide sugar metabolism, increased expression levels of genes such as chic, chs1, and gck genes, alongside decreased expression levels of the chia.1 gene, resulted in significantly elevated concentrations of N-Acetyl-D-glucosamine, β-d-fructose 6-phosphate, β-d-Fructose, D-mannose 6-phosphate, d-glucose, d-glucose 1-phosphate, UDP-glucose, and UDP-glucuronate, whilst the concentration of UDP-N-acetyl-α-D-glucosamine was markedly reduced. Therefore, the nesfatin-1 gene may influence the early development stage of largemouth bass by affecting signaling pathways associated with glycolipid metabolism. Our findings further expand the understanding of molecular mechanisms of the nesfatin-1 gene, and provide further theoretical support for the initial breeding and feed adaptation of largemouth bass.

Animals↗

PubMed2026

Qingfei Dayuan granules alleviate the inflammatory response in lipopolysaccharide-induced acute lung injury mice by inhibiting the Nf-κB signaling pathway and regulating the complement pathway.

OBJECTIVES: The study aimed to explore the effects and mechanisms by which Qingfei Dayuan granules (QFDY) mitigate pulmonary inflammation in lipopolysaccharide (LPS)-induced acute lung injury (ALI). METHODS: We established an ALI mouse model by intraperitoneal injection of LPS. HE, Transmission electron microscopy, ELISA assay of inflammatory cytokines, and immunohistochemistry (IHC) were used to assess the degree of lung injury and inflammation. Utilizing network analysis and proteomics analysis, the potential targets and pathways of QFDY were identified. Western blot, IHC, and qRT-PCR analysis were used to evaluate the potential mechanism of QFDY. Additionally, the chemical composition of QFDY were performed using UPLC-MS/MS. KEY FINDINGS: QFDY reduced the pathologic changes and inflammatory cell infiltration in lung tissue inflammation. Network and proteomic analysis showed that the mechanism of QFDY protection against ALI is closely related to the Nuclear factor-kappa B (NF-κB) signaling pathway and complement pathway. Animal experiments showed that Qingfei Dayuan granules (QFDY) significantly reduced the levels of IL-1β, IL-6, TNF-α, and lung tissue F4/80-positive alveolar macrophages. Additionally, western blot and qRT-PCR analyses showed the inhibition of the NF-κB pathway. Notably, the levels of mannose-binding lectin (MBL2) were significantly increased, while complement C3a and complement C5a proteins were reduced in the QFDY group compared to the LPS group. CONCLUSIONS: QFDY suppressed the inflammation in LPS-induced ALI by inhibiting the NF-κB and complement pathway.

Animals↗

PubMed2026

DPM2 promotes melanoma progression and serves as a prognostic factor.

Recently, dolichol phosphate mannose synthase (DPMS) has emerged as a promising new target for treatment in various cancers. Nonetheless, DPM2, a crucial element of the DPMS family, remains unexplored in melanoma research. This study aims to explore the predictive significance and biological role of DPM2, utilizing extensive databases and functional tests conducted in vitro. We conducted an in-depth examination of the DPM2 expression feature within The Cancer Genome Atlas database. Group differences were evaluated using Student's t-test, one-way analysis of variance, and long-rank test, while survival distributions were estimated using the Kaplan-Meier method. Functional experiments were conducted in multiple melanoma cell lines to evaluate the effects of altered DPM2 expression. Our research indicated a direct correlation between the expression levels of DPM2 and the severity of melanoma. In addition, an elevated level of DPM2 expression was significantly linked to unfavorable prognoses. Suppression of DPM2 inhibits the proliferation, migration, and invasion of melanoma cells and induces their apoptosis. These findings suggest that DPM2 plays a pivotal role in melanoma progression and may serve as an independent prognostic biomarker for the disease.

DPM2↗

PubMed2025

Identification of OxyR as an activator of type 1 fimbriae (fim) in Salmonella enterica serovar Typhi.

Salmonella enterica serovar Typhi (S. Typhi) encodes 14 fimbrial gene clusters, including the mannose-binding type 1 fimbriae known as Fim. Type 1 fimbriae have been implicated in biofilm formation and adhesion to host cells in Salmonella. However, their regulation in S. Typhi remains largely unknown. To identify genes affecting the regulation of fim in S. Typhi, we employed both a targeted and a genome-wide transposon-based screening approach. Overall, we identified 18 potential regulators of fim expression: 10 activators and 8 repressors. Two genes involved in the electron transport chain, yqiC and ndh, which encode the type II NADH dehydrogenase NDH-2, were identified. Both YqiC and NDH-2 contribute to the production of reactive oxygen species, prompting an investigation into the roles of oxidative stress response regulators OxyR and SoxR. We found that only OxyR regulates fim expression, which was specific to S. Typhi. OxyR acts by directly binding to the fimA promoter region. This study paves the way for future development of anti-adhesion strategies through the identification of 14 novel regulators for the most prominent fimbriae of S. Typhi.IMPORTANCEAdhesion mediated by fimbriae is one of the critical steps in the infection process. Therefore, it is essential to better understand the regulation of type 1 fimbriae (fim) in the human-specific pathogen Salmonella enterica serovar Typhi, the etiologic agent of typhoid fever. In this study, we identified 18 distinct mutants with altered regulation of fim. Furthermore, we confirmed that the DNA-binding protein OxyR directly regulates fim expression. Importantly, we also demonstrated regulatory differences in fim expression between S. Typhi and S. Typhimurium, as six of the genes identified altering fim expression in S. Typhi either did not affect fim expression in S. Typhimurium or had the contrary effect. This highlights fundamental differences between these serovars and emphasizes the need to investigate and compare aspects of gene regulation in S. Typhi.

Salmonella typhi↗

PubMed2026

Large-Scale Proteomic Profiling of Incident Heart Failure and Its Subtypes in Older Adults.

BACKGROUND: Heart failure (HF) and its main subtypes, heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF), impose an enormous health burden on elders. Assessment of the circulating proteome to illuminate pathogenesis could open new opportunities for treatment. METHODS: We conducted a plasma proteomics screen of incident HF and its subtypes in 2 older population-based cohorts, the CHS (Cardiovascular Health Study) and the AGES-RS (Aging, Gene/Environment Susceptibility-Reykjavik Study). The 2 studies used SomaLogic platforms, with 4404 aptamers in common. Multivariable Cox models were fit to evaluate individual-protein associations with HF, HFpEF, and HFrEF separately in each cohort, and study-specific associations were combined by fixed-effects meta-analysis. Replication was performed in the ARIC (Atherosclerosis Risk in Communities) cohort. Two-sample Mendelian randomization of HF and its subtypes, along with colocalization analysis, was performed to support causal inference. RESULTS: Among 8599 participants, 1590 experienced incident HF (536 HFpEF, 471 HFrEF). There were 119 proteins associated with HF, 15 proteins with HFpEF, and 11 proteins with HFrEF, at Bonferroni-corrected significance. Among these, 9 have never previously been identified for cardiovascular diseases, and another 61 represent new associations with incident HF or its subtypes. Of these 70 proteins, 55 of the 66 available replicated externally. Mendelian randomization analysis revealed 7 proteins genetically associated with HF at nominal significance; 2 were separately associated with HFpEF, and another 2 with HFrEF. Seven of these 9 proteins (NPDC1 [neural proliferation differentiation and control protein 1], APOF [apolipoprotein F], LMAN2 [lectin, mannose-binding 2], ADIPOQ [adiponectin], CD14 [cluster of differentiation 14], ARHGAP1 [Rho GTPase-activating protein 1], C9 [complement 9]) showed new, possibly causal associations, although we did not detect evidence for colocalization. CONCLUSIONS: In this large-scale proteomic study involving 3 longitudinal cohorts of older adults, we identified and replicated 55 novel protein markers of HF or its subtypes, and 7 new, possibly causal proteins. These proteins may enhance risk prediction, improve understanding of pathobiology, and help prioritize targets for therapeutic development of these foremost disorders in elders.

Humans↗