{"gene":"B3GALT2","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":1998,"finding":"B3GALT2 encodes a UDP-galactose:β-N-acetyl-glucosamine β-1,3-galactosyltransferase, demonstrated by expression in the Baculovirus system showing transfer of galactose in β-1,3 linkage to GlcNAc acceptors, with kinetic properties similar to β3Gal-T1.","method":"Baculovirus expression system, enzymatic activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — direct in vitro enzymatic reconstitution with kinetic characterization, foundational paper with 138 citations","pmids":["9582303"],"is_preprint":false},{"year":2000,"finding":"B3GALT2 (β3Gal-T2), when expressed in CHO cells with Fuc-TIII, directs synthesis of sialyl-Lewis x on N-glycans (type 2 chains), in contrast to β3Gal-T5 which directs Lewis type 1 antigen synthesis; β3Gal-T2 does not efficiently direct Lewis type 1 antigen synthesis.","method":"CHO cell transfection, endo-β-galactosidase treatment of N-glycans, flow cytometry/immunochemical detection of Lewis antigens","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — cell-based reconstitution with glycan structural analysis, single lab but multiple orthogonal methods","pmids":["11058588"],"is_preprint":false},{"year":2017,"finding":"B3galt2 knockdown in trigeminal ganglion neurons reduces secretion of TNFα and IL-6 and inhibits expression of TLR4 and NF-κB, placing B3galt2 upstream of the TLR4/NF-κB signaling pathway in neuroinflammation induced by dental pulp LPS exposure.","method":"siRNA knockdown, ELISA, immunohistochemistry, western blot in rat trigeminal ganglion model","journal":"Neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function with defined molecular readouts; single lab, multiple orthogonal methods","pmids":["28257892"],"is_preprint":false},{"year":2021,"finding":"B3galt2 is expressed in brain microvascular endothelial cells; overexpression via lentiviral vector reduces infarct volume and preserves blood-brain barrier integrity after MCAO, and this is associated with upregulation of TGF-β1, TGF-βRII, and p-Smad2/3; B3galt2 heterozygous knockout mice show reduced TGF-β signaling and increased BBB damage, placing B3galt2 upstream of the TGF-β/Smad2/3 pathway in endothelial cells.","method":"Lentiviral overexpression, heterozygous knockout mouse model, MCAO, western blot, BBB permeability assay, intracerebroventricular r-TGF-β1 rescue","journal":"Neurochemistry international","confidence":"Medium","confidence_rationale":"Tier 2 — gain- and loss-of-function with rescue experiment and defined pathway readouts; single lab","pmids":["33524473"],"is_preprint":false},{"year":2021,"finding":"B3galt2 heterozygous knockout mice exhibit exacerbated ischemic brain damage and decreased Reelin and Dab1 levels after MCAO; intracerebroventricular recombinant human Reelin rescues infarct volume and neuronal loss in B3galt2+/- mice, placing B3galt2 upstream of the Reelin/Dab1 signaling pathway in neuronal survival.","method":"Heterozygous knockout mouse model, MCAO, intracerebroventricular rh-Reelin rescue, western blot, caspase-3 activity assay","journal":"Brain research bulletin","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function with rescue experiment placing B3galt2 in Reelin pathway; single lab","pmids":["33482286"],"is_preprint":false},{"year":2022,"finding":"B3galt2 genetic knockout (homozygous and heterozygous) in adult mice impairs spatial learning, causes neuronal loss, and produces synaptic dysfunction in hippocampus and somatosensory cortex; X-gal staining in heterozygous mice confirms high B3galt2 expression in hippocampal dentate gyrus.","method":"Homozygous/heterozygous knockout mice, Morris Water Maze, X-gal staining, immunofluorescence","journal":"Neuroreport","confidence":"Medium","confidence_rationale":"Tier 2 — clean KO with defined behavioral and cellular phenotype, direct localization","pmids":["36504040"],"is_preprint":false},{"year":2022,"finding":"Recombinant human B3galt2 administered intranasally after MCAO reduces infarct volume, BBB permeability, neuronal apoptosis, and oxidative stress; these neuroprotective effects are abolished by intracerebroventricular TGF-β1-siRNA, placing B3galt2 upstream of the TGF-β1 pathway; B3galt2 also inhibits NF-κB, IL-6, TNF-α, IL-1β, and NLRP3 inflammasome activation.","method":"Intranasal recombinant protein administration, TGF-β1-siRNA knockdown rescue experiment, MCAO mouse model, infarct volume, ELISA, western blot","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 — gain-of-function with siRNA-based pathway rescue; single lab, multiple readouts","pmids":["36094000"],"is_preprint":false},{"year":2022,"finding":"B3galt2 and F3/Contactin are co-localized in hippocampal regions; B3galt2 overexpression upregulates F3/Contactin expression, protects synapsin, and reduces neuronal apoptosis in diabetic mice; B3galt2 knockdown worsens cognitive impairment in diabetic mice, establishing B3galt2 as a regulator of F3/Contactin-mediated neuroprotection.","method":"Lentiviral overexpression, heterozygous knockout mice, immunohistochemistry co-localization, Morris Water Maze, western blot","journal":"Neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 — gain- and loss-of-function with co-localization and defined molecular pathway; single lab","pmids":["36509381"],"is_preprint":false},{"year":2025,"finding":"B3GALT2 overexpression in HEK293 and U2OS cells significantly enhances cellular uptake and activity of antisense oligonucleotides (ASOs) across multiple targets; this is mechanistically linked to upregulation of endocytic scavenger receptors CUBN and SCARA5, and enrichment of clathrin-mediated endocytosis gene sets, identifying B3GALT2 as a modulator of ASO cellular entry.","method":"Genome-wide ORF overexpression screen with splice reporter, ASO activity assays, transcriptomic analysis, gene set enrichment analysis, ASO uptake quantification","journal":"Molecular therapy. Nucleic acids","confidence":"Medium","confidence_rationale":"Tier 2 — unbiased screen validated in multiple cell lines with transcriptomic mechanistic follow-up; single lab","pmids":["41341746"],"is_preprint":false},{"year":2026,"finding":"TFAP2A directly binds to the B3GALT2 promoter (confirmed by ChIP-qPCR and dual-luciferase reporter assay) to transcriptionally activate B3GALT2; B3GALT2 overexpression inhibits NLRP3 inflammasome activation and pyroptosis (reducing NLRP3, ASC, caspase-1 p20, GSDMD-N, LDH, IL-1β/IL-18) in LPS/MSU-stimulated THP-1 cells; B3GALT2 knockdown abolishes the anti-pyroptotic effects of TFAP2A overexpression.","method":"ChIP-qPCR, dual-luciferase reporter assay, gain- and loss-of-function in THP-1 cells, western blot, LDH assay, ELISA","journal":"Journal of orthopaedic surgery and research","confidence":"Medium","confidence_rationale":"Tier 1-2 — direct promoter binding confirmed by ChIP and luciferase, epistasis via knockdown rescue; single lab","pmids":["41654938"],"is_preprint":false},{"year":2026,"finding":"Recombinant human B3galt2 promotes cerebral angiogenesis during ischemic repair by activating the TGF-βRII/ALK1/Smad1/5 pathway; B3galt2 treatment increases galactosylation levels of TGF-βRII and ALK1 (glycosylation modification), and the pro-angiogenic and neuroprotective effects are abolished by the ALK1 inhibitor ML347, establishing B3galt2's mechanism as glycosylation of TGF-βRII/ALK1 to activate downstream Smad1/5 signaling.","method":"Intranasal rh-B3galt2, MCAO mouse model, ALK1 inhibitor (ML347) rescue, western blot for galactosylation, VEGFA/tight junction protein measurement","journal":"Experimental neurology","confidence":"Medium","confidence_rationale":"Tier 2 — pharmacological inhibitor rescue establishes pathway, glycosylation modification directly measured; single lab","pmids":["41565095"],"is_preprint":false}],"current_model":"B3GALT2 is a UDP-galactose:β-N-acetyl-glucosamine β-1,3-galactosyltransferase that glycosylates substrates including TGF-βRII and ALK1 to activate TGF-β/Smad signaling, regulates neuroinflammation via TLR4/NF-κB, Reelin/Dab1, and F3/Contactin pathways, suppresses NLRP3 inflammasome-mediated pyroptosis (transcriptionally activated by TFAP2A), and modulates cellular uptake of antisense oligonucleotides by upregulating scavenger receptors and clathrin-mediated endocytosis."},"narrative":{"teleology":[{"year":1998,"claim":"Establishing the enzymatic identity of B3GALT2 as a β-1,3-galactosyltransferase resolved what catalytic activity the gene encodes and provided the biochemical foundation for all subsequent functional studies.","evidence":"Recombinant expression in Baculovirus system with kinetic characterization of galactose transfer to GlcNAc acceptors","pmids":["9582303"],"confidence":"High","gaps":["Physiological glycoprotein substrates were not identified","No tissue-specific expression or in vivo function addressed","Structural basis for substrate specificity not determined"]},{"year":2000,"claim":"Demonstrating that B3GALT2 directs sialyl-Lewis x synthesis on N-glycans (type 2 chains) in living cells defined the glycan products it generates in a cellular context and distinguished it from the related β3Gal-T5.","evidence":"CHO cell co-transfection with Fuc-TIII, endo-β-galactosidase glycan analysis, and flow cytometry for Lewis antigens","pmids":["11058588"],"confidence":"Medium","gaps":["Endogenous cell types where B3GALT2 is the rate-limiting galactosyltransferase for Lewis antigen synthesis were not identified","Functional consequences of sialyl-Lewis x on specific glycoproteins not explored"]},{"year":2017,"claim":"Showing that B3galt2 knockdown reduces TLR4/NF-κB signaling and cytokine secretion in sensory neurons established B3GALT2 as a regulator of innate immune signaling in the nervous system, extending its role beyond glycan biosynthesis.","evidence":"siRNA knockdown in rat trigeminal ganglion neurons with ELISA, western blot, and immunohistochemistry readouts","pmids":["28257892"],"confidence":"Medium","gaps":["Whether B3GALT2 directly glycosylates TLR4 or acts indirectly was not determined","Findings from a single lab in one neuronal cell type"]},{"year":2021,"claim":"Gain- and loss-of-function studies in ischemic stroke models placed B3GALT2 upstream of both TGF-β/Smad2/3 signaling (for BBB protection) and Reelin/Dab1 signaling (for neuronal survival), revealing two distinct downstream effector pathways for its neuroprotective action.","evidence":"Lentiviral overexpression and heterozygous KO mice subjected to MCAO, with intracerebroventricular TGF-β1 and recombinant Reelin rescue experiments","pmids":["33524473","33482286"],"confidence":"Medium","gaps":["Whether B3GALT2 directly glycosylates Reelin or Dab1 was not tested","Heterozygous KO may not reveal full loss-of-function phenotype","Pathway cross-talk between TGF-β and Reelin arms not addressed"]},{"year":2022,"claim":"Genetic knockout revealed that B3GALT2 is required for normal hippocampal function, spatial learning, and synaptic integrity in adult mice, and that it regulates F3/Contactin-mediated neuroprotection and NLRP3 inflammasome suppression in vivo.","evidence":"Homozygous and heterozygous KO mice with Morris Water Maze, X-gal localization; intranasal recombinant B3galt2 with TGF-β1-siRNA rescue in MCAO; lentiviral overexpression/knockdown in diabetic mice","pmids":["36504040","36094000","36509381"],"confidence":"Medium","gaps":["Glycoprotein substrates responsible for synaptic phenotype not identified","All in vivo neuroprotection studies from a single research group","Molecular link between B3GALT2 and F3/Contactin expression change (glycosylation vs. transcription) not resolved"]},{"year":2025,"claim":"A genome-wide screen identified B3GALT2 as a modulator of antisense oligonucleotide cellular uptake, mechanistically linked to upregulation of endocytic scavenger receptors and clathrin-mediated endocytosis, revealing an unexpected role in regulating receptor-mediated endocytic trafficking.","evidence":"ORF overexpression screen with splice reporter in HEK293/U2OS cells, transcriptomic and gene set enrichment analysis","pmids":["41341746"],"confidence":"Medium","gaps":["Whether scavenger receptor upregulation requires B3GALT2 catalytic activity was not tested","Mechanism connecting galactosyltransferase activity to transcriptional changes in endocytic genes is unknown","Single lab finding"]},{"year":2026,"claim":"Identification of TGF-βRII and ALK1 as direct glycosylation substrates of B3GALT2, and of TFAP2A as a transcriptional activator of B3GALT2, provided the first molecular mechanism connecting B3GALT2 catalytic activity to specific receptor activation and placed B3GALT2 within a defined transcriptional regulatory circuit that suppresses NLRP3 inflammasome-mediated pyroptosis.","evidence":"Galactosylation measurement of TGF-βRII/ALK1 by western blot, ALK1 inhibitor ML347 rescue in MCAO mice; ChIP-qPCR and dual-luciferase for TFAP2A binding, epistasis in THP-1 cells","pmids":["41565095","41654938"],"confidence":"Medium","gaps":["Specific glycosylation sites on TGF-βRII and ALK1 not mapped","Whether TFAP2A-B3GALT2-NLRP3 axis operates in vivo not confirmed","Both studies from single labs; independent replication pending"]},{"year":null,"claim":"The precise glycosylation sites on TGF-βRII, ALK1, and other substrates, the structural basis for B3GALT2 substrate selectivity, and the mechanism by which its galactosyltransferase activity influences transcription of endocytic and inflammatory genes remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No crystal or cryo-EM structure of B3GALT2","Full glycoproteomic identification of endogenous substrates not performed","Whether catalytic activity is required for all reported signaling effects (vs. scaffolding) not tested with catalytic-dead mutants"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,1,10]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[6,10]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,3,4,6,10]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[2,9]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,1,10]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[8]}],"complexes":[],"partners":["TGFBR2","ACVRL1","TFAP2A","CNTN1","RELN","DAB1","NLRP3"],"other_free_text":[]},"mechanistic_narrative":"B3GALT2 is a UDP-galactose:β-N-acetyl-glucosamine β-1,3-galactosyltransferase that catalyzes the transfer of galactose in β-1,3 linkage to GlcNAc acceptors on N-glycans and glycoprotein substrates, functioning in glycosylation-dependent signaling and neuronal homeostasis [PMID:9582303, PMID:11058588]. B3GALT2 galactosylates TGF-βRII and ALK1 to activate TGF-β/Smad signaling, thereby promoting blood-brain barrier integrity, cerebral angiogenesis, and neuroprotection after ischemic injury [PMID:33524473, PMID:41565095]. Beyond TGF-β signaling, B3GALT2 suppresses NLRP3 inflammasome-mediated pyroptosis downstream of transcriptional activation by TFAP2A, modulates neuroinflammation through the TLR4/NF-κB axis, regulates F3/Contactin and Reelin/Dab1 neuroprotective pathways, and enhances antisense oligonucleotide cellular uptake by upregulating endocytic scavenger receptors [PMID:41654938, PMID:28257892, PMID:36509381, PMID:33482286, PMID:41341746]. Genetic knockout in mice causes spatial learning deficits, neuronal loss, and synaptic dysfunction in the hippocampus, establishing a requirement for B3GALT2 in normal brain function [PMID:36504040]."},"prefetch_data":{"uniprot":{"accession":"O43825","full_name":"Beta-1,3-galactosyltransferase 2","aliases":["UDP-galactose:2-acetamido-2-deoxy-D-glucose 3beta-galactosyltransferase 2"],"length_aa":422,"mass_kda":49.2,"function":"Beta-1,3-galactosyltransferase that transfers galactose from UDP-galactose to substrates with a terminal beta-N-acetylglucosamine (beta-GlcNAc) residue. Can also utilize substrates with a terminal galactose residue, albeit with lower efficiency. Involved in the biosynthesis of the carbohydrate moieties of glycolipids and glycoproteins. Inactive towards substrates with terminal alpha-N-acetylglucosamine (alpha-GlcNAc) or alpha-N-acetylgalactosamine (alpha-GalNAc) residues","subcellular_location":"Golgi apparatus membrane","url":"https://www.uniprot.org/uniprotkb/O43825/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/B3GALT2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/B3GALT2","total_profiled":1310},"omim":[{"mim_id":"603018","title":"BETA-3-GALACTOSYLTRANSFERASE 2; B3GALT2","url":"https://www.omim.org/entry/603018"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":15.3},{"tissue":"gallbladder","ntpm":14.1},{"tissue":"heart muscle","ntpm":19.7}],"url":"https://www.proteinatlas.org/search/B3GALT2"},"hgnc":{"alias_symbol":["beta3Gal-T2"],"prev_symbol":[]},"alphafold":{"accession":"O43825","domains":[{"cath_id":"3.90.550","chopping":"133-363","consensus_level":"high","plddt":96.5421,"start":133,"end":363}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O43825","model_url":"https://alphafold.ebi.ac.uk/files/AF-O43825-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O43825-F1-predicted_aligned_error_v6.png","plddt_mean":78.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=B3GALT2","jax_strain_url":"https://www.jax.org/strain/search?query=B3GALT2"},"sequence":{"accession":"O43825","fasta_url":"https://rest.uniprot.org/uniprotkb/O43825.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O43825/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O43825"}},"corpus_meta":[{"pmid":"9582303","id":"PMC_9582303","title":"A family of human beta3-galactosyltransferases. Characterization of four members of a UDP-galactose:beta-N-acetyl-glucosamine/beta-nacetyl-galactosamine beta-1,3-galactosyltransferase family.","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9582303","citation_count":138,"is_preprint":false},{"pmid":"11058588","id":"PMC_11058588","title":"beta 1,3-Galactosyltransferase beta 3Gal-T5 acts on the GlcNAcbeta 1-->3Galbeta 1-->4GlcNAcbeta 1-->R sugar chains of carcinoembryonic antigen and other N-linked glycoproteins and is down-regulated in colon adenocarcinomas.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11058588","citation_count":51,"is_preprint":false},{"pmid":"21837707","id":"PMC_21837707","title":"Detection of the first gross CDC73 germline deletion in an HPT-JT syndrome family.","date":"2011","source":"Genes, chromosomes & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/21837707","citation_count":35,"is_preprint":false},{"pmid":"34332599","id":"PMC_34332599","title":"Extracellular vesicle-derived AEBP1 mRNA as a novel candidate biomarker for diabetic kidney disease.","date":"2021","source":"Journal of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34332599","citation_count":27,"is_preprint":false},{"pmid":"35936781","id":"PMC_35936781","title":"Clinical Eosinophil-Associated Genes can Serve as a Reliable Predictor of Bladder Urothelial Cancer.","date":"2022","source":"Frontiers in molecular biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/35936781","citation_count":27,"is_preprint":false},{"pmid":"36094000","id":"PMC_36094000","title":"Intranasal administration of β-1, 3-galactosyltransferase 2 confers neuroprotection against ischemic stroke by likely inhibiting oxidative stress and NLRP3 inflammasome activation.","date":"2022","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/36094000","citation_count":19,"is_preprint":false},{"pmid":"33482286","id":"PMC_33482286","title":"β-1, 3-galactosyltransferase 2 deficiency exacerbates brain injury after transient focal cerebral ischemia in mice.","date":"2021","source":"Brain research bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/33482286","citation_count":14,"is_preprint":false},{"pmid":"36504680","id":"PMC_36504680","title":"Altered expression of glycobiology-related genes in Parkinson's disease brain.","date":"2022","source":"Frontiers in molecular neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/36504680","citation_count":12,"is_preprint":false},{"pmid":"28257892","id":"PMC_28257892","title":"Role of β-1,3-galactosyltransferase 2 in trigeminal neuronal sensitization induced by peripheral inflammation.","date":"2017","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/28257892","citation_count":11,"is_preprint":false},{"pmid":"33524473","id":"PMC_33524473","title":"β-1, 3-galactosyltransferase 2 ameliorates focal ischemic cerebral injury by maintaining blood-brain barrier integrity.","date":"2021","source":"Neurochemistry international","url":"https://pubmed.ncbi.nlm.nih.gov/33524473","citation_count":9,"is_preprint":false},{"pmid":"36509381","id":"PMC_36509381","title":"Salidroside Alleviates Diabetic Cognitive Dysfunction Via B3galt2/F3/Contactin Signaling Pathway in Mice.","date":"2022","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/36509381","citation_count":8,"is_preprint":false},{"pmid":"35571069","id":"PMC_35571069","title":"Differential Long Non-Coding RNA Expression Analysis in Chronic Non-Atrophic Gastritis, Gastric Mucosal Intraepithelial Neoplasia, and Gastric Cancer Tissues.","date":"2022","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35571069","citation_count":7,"is_preprint":false},{"pmid":"29242757","id":"PMC_29242757","title":"Differential Gene Transcription of Extracellular Matrix Components in Response to In Vivo Corneal Crosslinking (CXL) in Rabbit Corneas.","date":"2017","source":"Translational vision science & technology","url":"https://pubmed.ncbi.nlm.nih.gov/29242757","citation_count":6,"is_preprint":false},{"pmid":"36504040","id":"PMC_36504040","title":"Effects of the genetic knockout of the β-1,3-galactosyltransferase 2 on spatial learning and neurons in the adult mouse hippocampus and somatosensory cortex.","date":"2022","source":"Neuroreport","url":"https://pubmed.ncbi.nlm.nih.gov/36504040","citation_count":2,"is_preprint":false},{"pmid":"40823751","id":"PMC_40823751","title":"Comparisons of miRNA profiles of exosomes derived from human iPSCs, ADSCs, and BMSCs and effects on chondrocyte function.","date":"2025","source":"Bone & joint research","url":"https://pubmed.ncbi.nlm.nih.gov/40823751","citation_count":2,"is_preprint":false},{"pmid":"32800559","id":"PMC_32800559","title":"Identification of microRNA-target genes in mice hippocampus at 1 week after pilocarpine-induced status epilepticus.","date":"2020","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/32800559","citation_count":2,"is_preprint":false},{"pmid":"41341746","id":"PMC_41341746","title":"An unbiased whole-genome open reading frame overexpression screen identifies B3GALT2, a novel inducer of cellular ASO activity.","date":"2025","source":"Molecular therapy. Nucleic acids","url":"https://pubmed.ncbi.nlm.nih.gov/41341746","citation_count":0,"is_preprint":false},{"pmid":"41654938","id":"PMC_41654938","title":"TFAP2A transcriptionally regulates B3GALT2 to affect gouty arthritis progression through pyroptosis: a study based on machine learning and multi-omics integration analysis.","date":"2026","source":"Journal of orthopaedic surgery and research","url":"https://pubmed.ncbi.nlm.nih.gov/41654938","citation_count":0,"is_preprint":false},{"pmid":"41565095","id":"PMC_41565095","title":"β-1, 3-galactosyltransferase 2 promotes cerebral angiogenesis and neurological recovery during the ischemic repair phase through glycosylation modification of TGF-βR(II)/ALK1.","date":"2026","source":"Experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/41565095","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13677,"output_tokens":3016,"usd":0.043136},"stage2":{"model":"claude-opus-4-6","input_tokens":6454,"output_tokens":2637,"usd":0.147292},"total_usd":0.190428,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"B3GALT2 encodes a UDP-galactose:β-N-acetyl-glucosamine β-1,3-galactosyltransferase, demonstrated by expression in the Baculovirus system showing transfer of galactose in β-1,3 linkage to GlcNAc acceptors, with kinetic properties similar to β3Gal-T1.\",\n      \"method\": \"Baculovirus expression system, enzymatic activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro enzymatic reconstitution with kinetic characterization, foundational paper with 138 citations\",\n      \"pmids\": [\"9582303\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"B3GALT2 (β3Gal-T2), when expressed in CHO cells with Fuc-TIII, directs synthesis of sialyl-Lewis x on N-glycans (type 2 chains), in contrast to β3Gal-T5 which directs Lewis type 1 antigen synthesis; β3Gal-T2 does not efficiently direct Lewis type 1 antigen synthesis.\",\n      \"method\": \"CHO cell transfection, endo-β-galactosidase treatment of N-glycans, flow cytometry/immunochemical detection of Lewis antigens\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — cell-based reconstitution with glycan structural analysis, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"11058588\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"B3galt2 knockdown in trigeminal ganglion neurons reduces secretion of TNFα and IL-6 and inhibits expression of TLR4 and NF-κB, placing B3galt2 upstream of the TLR4/NF-κB signaling pathway in neuroinflammation induced by dental pulp LPS exposure.\",\n      \"method\": \"siRNA knockdown, ELISA, immunohistochemistry, western blot in rat trigeminal ganglion model\",\n      \"journal\": \"Neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined molecular readouts; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"28257892\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"B3galt2 is expressed in brain microvascular endothelial cells; overexpression via lentiviral vector reduces infarct volume and preserves blood-brain barrier integrity after MCAO, and this is associated with upregulation of TGF-β1, TGF-βRII, and p-Smad2/3; B3galt2 heterozygous knockout mice show reduced TGF-β signaling and increased BBB damage, placing B3galt2 upstream of the TGF-β/Smad2/3 pathway in endothelial cells.\",\n      \"method\": \"Lentiviral overexpression, heterozygous knockout mouse model, MCAO, western blot, BBB permeability assay, intracerebroventricular r-TGF-β1 rescue\",\n      \"journal\": \"Neurochemistry international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain- and loss-of-function with rescue experiment and defined pathway readouts; single lab\",\n      \"pmids\": [\"33524473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"B3galt2 heterozygous knockout mice exhibit exacerbated ischemic brain damage and decreased Reelin and Dab1 levels after MCAO; intracerebroventricular recombinant human Reelin rescues infarct volume and neuronal loss in B3galt2+/- mice, placing B3galt2 upstream of the Reelin/Dab1 signaling pathway in neuronal survival.\",\n      \"method\": \"Heterozygous knockout mouse model, MCAO, intracerebroventricular rh-Reelin rescue, western blot, caspase-3 activity assay\",\n      \"journal\": \"Brain research bulletin\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with rescue experiment placing B3galt2 in Reelin pathway; single lab\",\n      \"pmids\": [\"33482286\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"B3galt2 genetic knockout (homozygous and heterozygous) in adult mice impairs spatial learning, causes neuronal loss, and produces synaptic dysfunction in hippocampus and somatosensory cortex; X-gal staining in heterozygous mice confirms high B3galt2 expression in hippocampal dentate gyrus.\",\n      \"method\": \"Homozygous/heterozygous knockout mice, Morris Water Maze, X-gal staining, immunofluorescence\",\n      \"journal\": \"Neuroreport\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined behavioral and cellular phenotype, direct localization\",\n      \"pmids\": [\"36504040\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Recombinant human B3galt2 administered intranasally after MCAO reduces infarct volume, BBB permeability, neuronal apoptosis, and oxidative stress; these neuroprotective effects are abolished by intracerebroventricular TGF-β1-siRNA, placing B3galt2 upstream of the TGF-β1 pathway; B3galt2 also inhibits NF-κB, IL-6, TNF-α, IL-1β, and NLRP3 inflammasome activation.\",\n      \"method\": \"Intranasal recombinant protein administration, TGF-β1-siRNA knockdown rescue experiment, MCAO mouse model, infarct volume, ELISA, western blot\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain-of-function with siRNA-based pathway rescue; single lab, multiple readouts\",\n      \"pmids\": [\"36094000\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"B3galt2 and F3/Contactin are co-localized in hippocampal regions; B3galt2 overexpression upregulates F3/Contactin expression, protects synapsin, and reduces neuronal apoptosis in diabetic mice; B3galt2 knockdown worsens cognitive impairment in diabetic mice, establishing B3galt2 as a regulator of F3/Contactin-mediated neuroprotection.\",\n      \"method\": \"Lentiviral overexpression, heterozygous knockout mice, immunohistochemistry co-localization, Morris Water Maze, western blot\",\n      \"journal\": \"Neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain- and loss-of-function with co-localization and defined molecular pathway; single lab\",\n      \"pmids\": [\"36509381\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"B3GALT2 overexpression in HEK293 and U2OS cells significantly enhances cellular uptake and activity of antisense oligonucleotides (ASOs) across multiple targets; this is mechanistically linked to upregulation of endocytic scavenger receptors CUBN and SCARA5, and enrichment of clathrin-mediated endocytosis gene sets, identifying B3GALT2 as a modulator of ASO cellular entry.\",\n      \"method\": \"Genome-wide ORF overexpression screen with splice reporter, ASO activity assays, transcriptomic analysis, gene set enrichment analysis, ASO uptake quantification\",\n      \"journal\": \"Molecular therapy. Nucleic acids\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — unbiased screen validated in multiple cell lines with transcriptomic mechanistic follow-up; single lab\",\n      \"pmids\": [\"41341746\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"TFAP2A directly binds to the B3GALT2 promoter (confirmed by ChIP-qPCR and dual-luciferase reporter assay) to transcriptionally activate B3GALT2; B3GALT2 overexpression inhibits NLRP3 inflammasome activation and pyroptosis (reducing NLRP3, ASC, caspase-1 p20, GSDMD-N, LDH, IL-1β/IL-18) in LPS/MSU-stimulated THP-1 cells; B3GALT2 knockdown abolishes the anti-pyroptotic effects of TFAP2A overexpression.\",\n      \"method\": \"ChIP-qPCR, dual-luciferase reporter assay, gain- and loss-of-function in THP-1 cells, western blot, LDH assay, ELISA\",\n      \"journal\": \"Journal of orthopaedic surgery and research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 — direct promoter binding confirmed by ChIP and luciferase, epistasis via knockdown rescue; single lab\",\n      \"pmids\": [\"41654938\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Recombinant human B3galt2 promotes cerebral angiogenesis during ischemic repair by activating the TGF-βRII/ALK1/Smad1/5 pathway; B3galt2 treatment increases galactosylation levels of TGF-βRII and ALK1 (glycosylation modification), and the pro-angiogenic and neuroprotective effects are abolished by the ALK1 inhibitor ML347, establishing B3galt2's mechanism as glycosylation of TGF-βRII/ALK1 to activate downstream Smad1/5 signaling.\",\n      \"method\": \"Intranasal rh-B3galt2, MCAO mouse model, ALK1 inhibitor (ML347) rescue, western blot for galactosylation, VEGFA/tight junction protein measurement\",\n      \"journal\": \"Experimental neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological inhibitor rescue establishes pathway, glycosylation modification directly measured; single lab\",\n      \"pmids\": [\"41565095\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"B3GALT2 is a UDP-galactose:β-N-acetyl-glucosamine β-1,3-galactosyltransferase that glycosylates substrates including TGF-βRII and ALK1 to activate TGF-β/Smad signaling, regulates neuroinflammation via TLR4/NF-κB, Reelin/Dab1, and F3/Contactin pathways, suppresses NLRP3 inflammasome-mediated pyroptosis (transcriptionally activated by TFAP2A), and modulates cellular uptake of antisense oligonucleotides by upregulating scavenger receptors and clathrin-mediated endocytosis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"B3GALT2 is a UDP-galactose:β-N-acetyl-glucosamine β-1,3-galactosyltransferase that catalyzes the transfer of galactose in β-1,3 linkage to GlcNAc acceptors on N-glycans and glycoprotein substrates, functioning in glycosylation-dependent signaling and neuronal homeostasis [PMID:9582303, PMID:11058588]. B3GALT2 galactosylates TGF-βRII and ALK1 to activate TGF-β/Smad signaling, thereby promoting blood-brain barrier integrity, cerebral angiogenesis, and neuroprotection after ischemic injury [PMID:33524473, PMID:41565095]. Beyond TGF-β signaling, B3GALT2 suppresses NLRP3 inflammasome-mediated pyroptosis downstream of transcriptional activation by TFAP2A, modulates neuroinflammation through the TLR4/NF-κB axis, regulates F3/Contactin and Reelin/Dab1 neuroprotective pathways, and enhances antisense oligonucleotide cellular uptake by upregulating endocytic scavenger receptors [PMID:41654938, PMID:28257892, PMID:36509381, PMID:33482286, PMID:41341746]. Genetic knockout in mice causes spatial learning deficits, neuronal loss, and synaptic dysfunction in the hippocampus, establishing a requirement for B3GALT2 in normal brain function [PMID:36504040].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Establishing the enzymatic identity of B3GALT2 as a β-1,3-galactosyltransferase resolved what catalytic activity the gene encodes and provided the biochemical foundation for all subsequent functional studies.\",\n      \"evidence\": \"Recombinant expression in Baculovirus system with kinetic characterization of galactose transfer to GlcNAc acceptors\",\n      \"pmids\": [\"9582303\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Physiological glycoprotein substrates were not identified\",\n        \"No tissue-specific expression or in vivo function addressed\",\n        \"Structural basis for substrate specificity not determined\"\n      ]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstrating that B3GALT2 directs sialyl-Lewis x synthesis on N-glycans (type 2 chains) in living cells defined the glycan products it generates in a cellular context and distinguished it from the related β3Gal-T5.\",\n      \"evidence\": \"CHO cell co-transfection with Fuc-TIII, endo-β-galactosidase glycan analysis, and flow cytometry for Lewis antigens\",\n      \"pmids\": [\"11058588\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Endogenous cell types where B3GALT2 is the rate-limiting galactosyltransferase for Lewis antigen synthesis were not identified\",\n        \"Functional consequences of sialyl-Lewis x on specific glycoproteins not explored\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showing that B3galt2 knockdown reduces TLR4/NF-κB signaling and cytokine secretion in sensory neurons established B3GALT2 as a regulator of innate immune signaling in the nervous system, extending its role beyond glycan biosynthesis.\",\n      \"evidence\": \"siRNA knockdown in rat trigeminal ganglion neurons with ELISA, western blot, and immunohistochemistry readouts\",\n      \"pmids\": [\"28257892\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether B3GALT2 directly glycosylates TLR4 or acts indirectly was not determined\",\n        \"Findings from a single lab in one neuronal cell type\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Gain- and loss-of-function studies in ischemic stroke models placed B3GALT2 upstream of both TGF-β/Smad2/3 signaling (for BBB protection) and Reelin/Dab1 signaling (for neuronal survival), revealing two distinct downstream effector pathways for its neuroprotective action.\",\n      \"evidence\": \"Lentiviral overexpression and heterozygous KO mice subjected to MCAO, with intracerebroventricular TGF-β1 and recombinant Reelin rescue experiments\",\n      \"pmids\": [\"33524473\", \"33482286\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether B3GALT2 directly glycosylates Reelin or Dab1 was not tested\",\n        \"Heterozygous KO may not reveal full loss-of-function phenotype\",\n        \"Pathway cross-talk between TGF-β and Reelin arms not addressed\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Genetic knockout revealed that B3GALT2 is required for normal hippocampal function, spatial learning, and synaptic integrity in adult mice, and that it regulates F3/Contactin-mediated neuroprotection and NLRP3 inflammasome suppression in vivo.\",\n      \"evidence\": \"Homozygous and heterozygous KO mice with Morris Water Maze, X-gal localization; intranasal recombinant B3galt2 with TGF-β1-siRNA rescue in MCAO; lentiviral overexpression/knockdown in diabetic mice\",\n      \"pmids\": [\"36504040\", \"36094000\", \"36509381\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Glycoprotein substrates responsible for synaptic phenotype not identified\",\n        \"All in vivo neuroprotection studies from a single research group\",\n        \"Molecular link between B3GALT2 and F3/Contactin expression change (glycosylation vs. transcription) not resolved\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A genome-wide screen identified B3GALT2 as a modulator of antisense oligonucleotide cellular uptake, mechanistically linked to upregulation of endocytic scavenger receptors and clathrin-mediated endocytosis, revealing an unexpected role in regulating receptor-mediated endocytic trafficking.\",\n      \"evidence\": \"ORF overexpression screen with splice reporter in HEK293/U2OS cells, transcriptomic and gene set enrichment analysis\",\n      \"pmids\": [\"41341746\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether scavenger receptor upregulation requires B3GALT2 catalytic activity was not tested\",\n        \"Mechanism connecting galactosyltransferase activity to transcriptional changes in endocytic genes is unknown\",\n        \"Single lab finding\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Identification of TGF-βRII and ALK1 as direct glycosylation substrates of B3GALT2, and of TFAP2A as a transcriptional activator of B3GALT2, provided the first molecular mechanism connecting B3GALT2 catalytic activity to specific receptor activation and placed B3GALT2 within a defined transcriptional regulatory circuit that suppresses NLRP3 inflammasome-mediated pyroptosis.\",\n      \"evidence\": \"Galactosylation measurement of TGF-βRII/ALK1 by western blot, ALK1 inhibitor ML347 rescue in MCAO mice; ChIP-qPCR and dual-luciferase for TFAP2A binding, epistasis in THP-1 cells\",\n      \"pmids\": [\"41565095\", \"41654938\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Specific glycosylation sites on TGF-βRII and ALK1 not mapped\",\n        \"Whether TFAP2A-B3GALT2-NLRP3 axis operates in vivo not confirmed\",\n        \"Both studies from single labs; independent replication pending\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The precise glycosylation sites on TGF-βRII, ALK1, and other substrates, the structural basis for B3GALT2 substrate selectivity, and the mechanism by which its galactosyltransferase activity influences transcription of endocytic and inflammatory genes remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No crystal or cryo-EM structure of B3GALT2\",\n        \"Full glycoproteomic identification of endogenous substrates not performed\",\n        \"Whether catalytic activity is required for all reported signaling effects (vs. scaffolding) not tested with catalytic-dead mutants\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 1, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [6, 10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 3, 4, 6, 10]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [2, 9]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 10]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"TGFBR2\",\n      \"ACVRL1\",\n      \"TFAP2A\",\n      \"CNTN1\",\n      \"RELN\",\n      \"DAB1\",\n      \"NLRP3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}