{"gene":"NTF3","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":1991,"finding":"NTF3 (NGF-2) promotes survival of dorsal root ganglion (DRG) and nodose ganglion sensory neurons in vitro, demonstrating neurotrophic activity distinct from NGF; conditioned medium from COS cells expressing human NGF-2 cDNA was sufficient to support neuronal survival.","method":"In vitro neuronal survival assay using conditioned medium from COS cells transfected with human NGF-2 cDNA expression plasmid","journal":"Research communications - Institute for Fermentation, Osaka","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — direct in vitro functional assay establishing neurotrophic activity, but single lab, single method, no mechanistic dissection of receptor or pathway","pmids":["1367285"],"is_preprint":false},{"year":2012,"finding":"NTF3 activates TrkB to induce anoikis resistance in triple-negative breast cancer (TNBC) cells; NF-κB (via RelA and NF-κB1 subunits) transcriptionally up-regulates both TrkB and NTF3 upon cell suspension, and NTF3 is a direct post-transcriptional target of miR-200c.","method":"Luciferase reporter assay (miR-200c targeting NTF3 3'UTR), NF-κB inhibition experiments, suspension-induced expression analysis, functional anoikis assays","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal functional assays (miR-200c targeting, NF-κB inhibition, receptor activation), multiple methods in single lab","pmids":["23185507"],"is_preprint":false},{"year":2014,"finding":"In developing mouse neocortex, Ntf3 acts downstream of Sip1 (Zeb2) as a feedback signal from postmitotic neurons to progenitors, promoting the switch from apical progenitors (AP) to basal progenitors (BP) and from deep-layer to upper-layer neuronal fate; Ntf3 overexpression in neurons increases BP production at the expense of APs, while Ntf3 loss increases layer VI neurons.","method":"Genetic epistasis in mouse neocortex: conditional Ntf3 overexpression in neurons, Ntf3 loss-of-function (knockout), comparison with Sip1 mutant phenotype","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with both gain- and loss-of-function in vivo, multiple neuronal layer phenotypes quantified, pathway placement established","pmids":["25085976"],"is_preprint":false},{"year":2015,"finding":"AAV-delivered Ntf3 gene transfer to the deafened guinea pig cochlea promotes regrowth of peripheral auditory fibers (PAFs) in the basilar membrane area; however, BDNF was more effective than NT-3 in preserving spiral ganglion neurons (SGNs), indicating differential neurotrophin effects in the auditory system.","method":"In vivo AAV vector delivery (AAV.Ntf3 vs AAV.BDNF) in deafened guinea pig cochlea; morphological assessment of PAF regrowth and SGN counts at 3 months","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo gene delivery with morphological outcome measures, direct comparison of Ntf3 vs BDNF effects, single lab","pmids":["25726967"],"is_preprint":false},{"year":2016,"finding":"Viral-mediated overexpression of Ntf3 in normal (non-deafened) guinea pig cochlea disrupts peripheral nerve endings and synaptic connections between inner hair cells and auditory nerve fibers, causing hearing threshold shifts, indicating that the level of NT-3 must be tightly regulated for normal cochlear synapse maintenance.","method":"Adenovirus and AAV Ntf3 vector inoculation into perilymph/endolymph of normal guinea pig cochlea; ABR threshold measurements and histological evaluation of hair cells, nerve endings, and synaptic ribbons","journal":"Molecular therapy. Methods & clinical development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct in vivo loss-of-normal-function experiment with electrophysiological and histological readouts, single lab","pmids":["27525291"],"is_preprint":false},{"year":2018,"finding":"Transcription factor POU3F2 directly binds the NTF3 promoter and positively regulates its transcription during neuronal differentiation; POU3F2 knockdown downregulates NTF3, and recombinant NTF3 rescues neuronal viability and differentiation in both NTF3- and POU3F2-knockdown cells.","method":"ChIP-seq, promoter deletion/mutation luciferase reporter assay, siRNA knockdown, rescue with recombinant NTF3 protein, co-immunostaining in developing mouse neurons","journal":"Molecular neurobiology","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — multiple orthogonal methods (ChIP-seq, promoter mutagenesis with reporter, knockdown rescue) in single lab establishing direct transcriptional regulation","pmids":["29549646"],"is_preprint":false},{"year":2008,"finding":"A novel missense variant G76R in NTF3, found in two HSCR patients but absent in controls, is postulated to disrupt the NTF3/TrkC signaling pathway required for proper enteric nervous system development; the NTF3/TrkC signaling axis is implicated in neural crest cell migration, proliferation, and differentiation for ENS formation.","method":"Mutational screening of NTF3 in HSCR patients and controls; SNP association analysis","journal":"Journal of pediatric surgery","confidence":"Low","confidence_rationale":"Tier 3 / Weak — genetic association/screening study without direct functional validation of the variant; no in vitro or in vivo mechanistic assay performed","pmids":["18639687"],"is_preprint":false},{"year":2025,"finding":"X-ray crystal structure of NTF3 in complex with an anti-NTF3 Fab revealed that NTF3 contains a flexible loop that becomes ordered upon Fab binding; NTF3 is a cysteine-knot protein that engages the Trk family of receptor tyrosine kinases. Neutralizing antibodies that inhibit NTF3 functional activity were isolated, confirming receptor engagement as the functional mechanism.","method":"X-ray crystallography of Fab/NTF3 complex; phage display antibody isolation; functional inhibition assays","journal":"SLAS discovery : advancing life sciences R & D","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structure with functional antibody validation, but single lab and abstract-level detail on structure","pmids":["39832740"],"is_preprint":false},{"year":2025,"finding":"miR-21 directly targets NTF3 in cervical cancer cells, as confirmed by dual luciferase reporter assay; overexpression of NTF3 inhibits cell proliferation and migration while promoting apoptosis, and NTF3 involvement in PI3K-AKT and MAPK signaling pathways was identified by transcriptome analysis.","method":"Dual luciferase reporter assay (miR-21 targeting NTF3 3'UTR), NTF3 overexpression with viability/migration/apoptosis assays, transcriptome sequencing with KEGG/GO enrichment","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct reporter assay confirming miRNA-target relationship plus functional cellular assays, single lab","pmids":["39828780"],"is_preprint":false},{"year":2024,"finding":"Esketamine (ESK) treatment activates the NTF3/PI3K/AKT signaling pathway in a mouse intracerebral hemorrhage model; AAV-mediated knockdown of NTF3 in the striatum attenuated ESK neuroprotection, and pharmacological PI3K inhibition (LY294002) similarly blocked ESK therapeutic effects, placing NTF3 upstream of PI3K/AKT in ESK-mediated neurorepair.","method":"In vivo ICH mouse model; AAV-mediated NTF3 knockdown; PI3K inhibitor (LY294002); Western blotting, immunofluorescence, RNA transcriptome sequencing","journal":"CNS neuroscience & therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo genetic (AAV KD) and pharmacological epistasis placing NTF3 upstream of PI3K/AKT, multiple methods, single lab","pmids":["39690816"],"is_preprint":false}],"current_model":"NTF3 (neurotrophin-3/NGF-2) is a secreted cysteine-knot neurotrophic factor that activates Trk receptor tyrosine kinases (primarily TrkC, and also TrkB) to promote neuronal survival, differentiation, and synaptic maintenance; its transcription is directly driven by POU3F2 binding to its promoter and by NF-κB during stress, it acts as a retrograde feedback signal from postmitotic neurons to cortical progenitors to control fate-switching, and it signals downstream through PI3K/AKT and MAPK pathways, with its expression level and localization being tightly regulated for normal cochlear synapse integrity."},"narrative":{"mechanistic_narrative":"NTF3 (neurotrophin-3/NGF-2) is a secreted cysteine-knot neurotrophic factor that signals through the Trk family of receptor tyrosine kinases to control neuronal survival, fate, and synaptic integrity [PMID:1367285, PMID:39832740]. It promotes survival of dorsal root ganglion and nodose ganglion sensory neurons, defining a neurotrophic activity distinct from NGF [PMID:1367285], and its functional output depends on Trk receptor engagement, as neutralizing anti-NTF3 antibodies that block receptor binding abolish its activity [PMID:39832740]. In the developing neocortex NTF3 acts downstream of Sip1 (Zeb2) as a retrograde feedback signal from postmitotic neurons to progenitors, driving the switch from apical to basal progenitors and from deep-layer to upper-layer neuronal fate; gain of NTF3 expands basal progenitors while its loss increases layer VI neurons [PMID:25085976]. Downstream signaling proceeds through PI3K/AKT, where AAV knockdown and pharmacological PI3K inhibition place NTF3 upstream of this axis in neuroprotection [PMID:39690816], and transcriptome analysis links it additionally to MAPK signaling [PMID:39828780]. NTF3 transcription is directly driven by POU3F2 binding to its promoter during neuronal differentiation [PMID:29549646] and is induced by NF-κB during cell-suspension stress [PMID:23185507], while its message is post-transcriptionally repressed by miR-200c and miR-21 [PMID:23185507, PMID:39828780]. In the cochlea NTF3 levels must be tightly balanced: gene transfer to deafened cochleae promotes regrowth of peripheral auditory fibers [PMID:25726967], whereas overexpression in normal cochleae disrupts inner-hair-cell synapses and shifts hearing thresholds [PMID:27525291].","teleology":[{"year":1991,"claim":"Established that NTF3 is a bona fide neurotrophic factor with target specificity distinct from NGF, defining its core biological activity.","evidence":"In vitro survival assay of DRG and nodose ganglion neurons using conditioned medium from COS cells expressing human NGF-2 cDNA","pmids":["1367285"],"confidence":"Medium","gaps":["Receptor responsible for survival not identified","No downstream signaling pathway dissected","Single lab, single method"]},{"year":2008,"claim":"Connected NTF3/TrkC signaling to enteric nervous system development by identifying a candidate missense variant in Hirschsprung disease patients.","evidence":"Mutational screening of NTF3 (G76R) in HSCR patients vs controls with SNP association","pmids":["18639687"],"confidence":"Low","gaps":["No functional validation of the G76R variant in vitro or in vivo","Causality not established","Small patient sample"]},{"year":2012,"claim":"Revealed an NF-κB-driven transcriptional and miRNA-controlled circuit governing NTF3 expression, and showed NTF3 can activate TrkB to confer anoikis resistance in cancer.","evidence":"Luciferase reporter (miR-200c/NTF3 3'UTR), NF-κB inhibition, suspension-induced expression, anoikis assays in TNBC cells","pmids":["23185507"],"confidence":"Medium","gaps":["TrkB activation shown functionally but direct binding not structurally resolved","Generality beyond TNBC unknown"]},{"year":2014,"claim":"Placed NTF3 as a retrograde feedback signal from neurons to progenitors controlling cortical fate-switching, positioning it within a developmental signaling hierarchy below Sip1.","evidence":"Genetic epistasis in mouse neocortex with conditional Ntf3 overexpression, knockout, and comparison to Sip1 mutants","pmids":["25085976"],"confidence":"High","gaps":["Receptor on progenitors mediating the feedback not defined","Downstream effector pathway in progenitors unresolved"]},{"year":2015,"claim":"Demonstrated therapeutic potential of NTF3 gene transfer for auditory fiber regrowth while showing neurotrophin-specific differences in spiral ganglion preservation.","evidence":"In vivo AAV.Ntf3 vs AAV.BDNF delivery in deafened guinea pig cochlea with morphological assessment","pmids":["25726967"],"confidence":"Medium","gaps":["Molecular basis of differential Ntf3 vs BDNF effects unresolved","Functional hearing recovery not assessed"]},{"year":2016,"claim":"Showed NTF3 dosage must be tightly regulated, as overexpression in healthy cochlea is itself pathogenic for synapses, refining the therapeutic window concept.","evidence":"Adeno/AAV Ntf3 inoculation into normal guinea pig cochlea with ABR and histology of synaptic ribbons","pmids":["27525291"],"confidence":"Medium","gaps":["Mechanism by which excess NT-3 disrupts synapses unknown","Receptor signaling threshold not quantified"]},{"year":2018,"claim":"Identified POU3F2 as a direct transcriptional activator of NTF3 during neuronal differentiation, defining an upstream regulator of its expression.","evidence":"ChIP-seq, promoter mutagenesis luciferase reporter, siRNA knockdown, and recombinant NTF3 rescue in mouse neurons","pmids":["29549646"],"confidence":"High","gaps":["Other promoter-binding regulators not mapped","In vivo relevance of POU3F2-NTF3 axis untested in animals"]},{"year":2024,"claim":"Placed NTF3 upstream of PI3K/AKT in neuroprotection, linking its activity to a defined intracellular survival pathway in CNS injury.","evidence":"Mouse ICH model with AAV NTF3 knockdown and PI3K inhibitor LY294002, with Western blot and transcriptomics","pmids":["39690816"],"confidence":"Medium","gaps":["Receptor coupling NTF3 to PI3K/AKT in striatum not identified","Direct vs indirect pathway engagement unresolved"]},{"year":2025,"claim":"Provided structural confirmation that NTF3 is a cysteine-knot protein engaging Trk receptors and that receptor engagement is the functional mechanism, validated by neutralizing antibodies; separately linked NTF3 to PI3K-AKT and MAPK in cancer.","evidence":"X-ray crystallography of Fab/NTF3 complex with phage-display antibody isolation and functional inhibition; miR-21/NTF3 luciferase reporter with proliferation/migration/apoptosis assays and transcriptome KEGG/GO analysis","pmids":["39832740","39828780"],"confidence":"Medium","gaps":["Crystal structure of NTF3 bound to a Trk receptor not reported","Receptor specificity (TrkC vs TrkB) in these contexts not resolved"]},{"year":null,"claim":"Which Trk receptor NTF3 engages in each tissue context and how receptor choice dictates the divergent outcomes (progenitor feedback, cochlear synapse maintenance, cancer survival vs suppression) remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of an NTF3-Trk complex","Receptor identity in cortical feedback and cochlear contexts not defined","Context-dependent pro- vs anti-tumor roles mechanistically unexplained"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,7]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[7,1]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[9,8]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[2]}],"complexes":[],"partners":["NTRK3","NTRK2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P20783","full_name":"Neurotrophin-3","aliases":["HDNF","Nerve growth factor 2","NGF-2","Neurotrophic factor"],"length_aa":257,"mass_kda":29.4,"function":"Seems to promote the survival of visceral and proprioceptive sensory neurons","subcellular_location":"Secreted","url":"https://www.uniprot.org/uniprotkb/P20783/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NTF3","classification":"Not Classified","n_dependent_lines":11,"n_total_lines":1208,"dependency_fraction":0.009105960264900662},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/NTF3","total_profiled":1310},"omim":[{"mim_id":"613160","title":"VON WILLEBRAND FACTOR; VWF","url":"https://www.omim.org/entry/613160"},{"mim_id":"610998","title":"METEORIN; METRN","url":"https://www.omim.org/entry/610998"},{"mim_id":"607409","title":"NEURITIN 1; NRN1","url":"https://www.omim.org/entry/607409"},{"mim_id":"605802","title":"ZINC FINGER E BOX-BINDING HOMEOBOX 2; ZEB2","url":"https://www.omim.org/entry/605802"},{"mim_id":"602186","title":"VGF, NERVE GROWTH FACTOR-INDUCIBLE; VGF","url":"https://www.omim.org/entry/602186"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"blood vessel","ntpm":26.5}],"url":"https://www.proteinatlas.org/search/NTF3"},"hgnc":{"alias_symbol":["NGF2"],"prev_symbol":[]},"alphafold":{"accession":"P20783","domains":[{"cath_id":"2.10.90.10","chopping":"91-113_151-253","consensus_level":"high","plddt":90.5977,"start":91,"end":253}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P20783","model_url":"https://alphafold.ebi.ac.uk/files/AF-P20783-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P20783-F1-predicted_aligned_error_v6.png","plddt_mean":73.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NTF3","jax_strain_url":"https://www.jax.org/strain/search?query=NTF3"},"sequence":{"accession":"P20783","fasta_url":"https://rest.uniprot.org/uniprotkb/P20783.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P20783/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P20783"}},"corpus_meta":[{"pmid":"23185507","id":"PMC_23185507","title":"miR-200c targets a NF-κB up-regulated TrkB/NTF3 autocrine signaling loop to enhance anoikis sensitivity in triple negative breast cancer.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23185507","citation_count":73,"is_preprint":false},{"pmid":"25085976","id":"PMC_25085976","title":"Ntf3 acts downstream of Sip1 in cortical postmitotic neurons to control progenitor cell fate through feedback signaling.","date":"2014","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/25085976","citation_count":60,"is_preprint":false},{"pmid":"25726967","id":"PMC_25726967","title":"Differential effects of AAV.BDNF and AAV.Ntf3 in the deafened adult guinea pig ear.","date":"2015","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/25726967","citation_count":49,"is_preprint":false},{"pmid":"29549646","id":"PMC_29549646","title":"NTF3 Is a Novel Target Gene of the Transcription Factor POU3F2 and Is Required for Neuronal Differentiation.","date":"2018","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/29549646","citation_count":35,"is_preprint":false},{"pmid":"29106055","id":"PMC_29106055","title":"Lnc-NTF3-5 promotes osteogenic differentiation of maxillary sinus membrane stem cells via sponging miR-93-3p.","date":"2017","source":"Clinical implant dentistry and related research","url":"https://pubmed.ncbi.nlm.nih.gov/29106055","citation_count":29,"is_preprint":false},{"pmid":"27525291","id":"PMC_27525291","title":"Viral-mediated Ntf3 overexpression disrupts innervation and hearing in nondeafened guinea pig cochleae.","date":"2016","source":"Molecular therapy. Methods & clinical development","url":"https://pubmed.ncbi.nlm.nih.gov/27525291","citation_count":25,"is_preprint":false},{"pmid":"18639687","id":"PMC_18639687","title":"NTF-3, a gene involved in the enteric nervous system development, as a candidate gene for Hirschsprung disease.","date":"2008","source":"Journal of pediatric surgery","url":"https://pubmed.ncbi.nlm.nih.gov/18639687","citation_count":24,"is_preprint":false},{"pmid":"15188132","id":"PMC_15188132","title":"The role of beta-catenin, TGF beta 3, NGF2, FGF2, IGFR2, and BMP4 in the pathogenesis of mesenteric sclerosis and angiopathy in midgut carcinoids.","date":"2004","source":"Human pathology","url":"https://pubmed.ncbi.nlm.nih.gov/15188132","citation_count":17,"is_preprint":false},{"pmid":"28614398","id":"PMC_28614398","title":"5-Aza-2'-deoxycytidine in the medial prefrontal cortex regulates alcohol-related behavior and Ntf3-TrkC expression in rats.","date":"2017","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/28614398","citation_count":14,"is_preprint":false},{"pmid":"39828780","id":"PMC_39828780","title":"miR-21 promotes cervical cancer by regulating NTF3.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/39828780","citation_count":10,"is_preprint":false},{"pmid":"39690816","id":"PMC_39690816","title":"Esketamine Provides Neuroprotection After Intracerebral Hemorrhage in Mice via the NTF3/PI3K/AKT Pathway.","date":"2024","source":"CNS neuroscience & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/39690816","citation_count":7,"is_preprint":false},{"pmid":"26814132","id":"PMC_26814132","title":"Polymorphisms of the neurotrophic factor-3 (NTF-3) in Alzheimer's disease: rs6332 associated with onset time and rs6489630 T allele exhibited a protective role.","date":"2015","source":"Journal of neurogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/26814132","citation_count":7,"is_preprint":false},{"pmid":"31841205","id":"PMC_31841205","title":"Regulation of Lnc-NTF3-5 on islet β-cell dysfunction in high glucose environment and related mechanisms.","date":"2019","source":"European review for medical and pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/31841205","citation_count":6,"is_preprint":false},{"pmid":"40051702","id":"PMC_40051702","title":"EDN1 and NTF3 in keloid pathogenesis: computational and experimental evidence as novel diagnostic biomarkers for fibrosis and inflammation.","date":"2025","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40051702","citation_count":5,"is_preprint":false},{"pmid":"41081890","id":"PMC_41081890","title":"Discovery metabolomics and genetic analysis reveal lipid pathway alterations associated with malignant phenotype acquisition in pleomorphic adenoma and a novel NTF3::ITPR2 fusion in carcinoma ex pleomorphic adenoma.","date":"2025","source":"Virchows Archiv : an international journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/41081890","citation_count":1,"is_preprint":false},{"pmid":"33655887","id":"PMC_33655887","title":"miRNAs regulating the expressions of NTF3, GNG2 and ITGA7 are involved in the pathogenesis of abdominal aortic aneurysm in mice.","date":"2021","source":"General physiology and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/33655887","citation_count":1,"is_preprint":false},{"pmid":"39832740","id":"PMC_39832740","title":"Identification of unique binding mode anti-NTF3 antibodies from a novel long VH CDR3 phage display library.","date":"2025","source":"SLAS discovery : advancing life sciences R & D","url":"https://pubmed.ncbi.nlm.nih.gov/39832740","citation_count":0,"is_preprint":false},{"pmid":"1367285","id":"PMC_1367285","title":"Effect of NGF-2 on the survival of chick sensory ganglion neurons in vitro.","date":"1991","source":"Research communications - Institute for Fermentation, Osaka","url":"https://pubmed.ncbi.nlm.nih.gov/1367285","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11495,"output_tokens":2690,"usd":0.037417,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9957,"output_tokens":3147,"usd":0.06423,"stage2_stop_reason":"end_turn"},"total_usd":0.101647,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1991,\n      \"finding\": \"NTF3 (NGF-2) promotes survival of dorsal root ganglion (DRG) and nodose ganglion sensory neurons in vitro, demonstrating neurotrophic activity distinct from NGF; conditioned medium from COS cells expressing human NGF-2 cDNA was sufficient to support neuronal survival.\",\n      \"method\": \"In vitro neuronal survival assay using conditioned medium from COS cells transfected with human NGF-2 cDNA expression plasmid\",\n      \"journal\": \"Research communications - Institute for Fermentation, Osaka\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — direct in vitro functional assay establishing neurotrophic activity, but single lab, single method, no mechanistic dissection of receptor or pathway\",\n      \"pmids\": [\"1367285\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"NTF3 activates TrkB to induce anoikis resistance in triple-negative breast cancer (TNBC) cells; NF-κB (via RelA and NF-κB1 subunits) transcriptionally up-regulates both TrkB and NTF3 upon cell suspension, and NTF3 is a direct post-transcriptional target of miR-200c.\",\n      \"method\": \"Luciferase reporter assay (miR-200c targeting NTF3 3'UTR), NF-κB inhibition experiments, suspension-induced expression analysis, functional anoikis assays\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal functional assays (miR-200c targeting, NF-κB inhibition, receptor activation), multiple methods in single lab\",\n      \"pmids\": [\"23185507\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In developing mouse neocortex, Ntf3 acts downstream of Sip1 (Zeb2) as a feedback signal from postmitotic neurons to progenitors, promoting the switch from apical progenitors (AP) to basal progenitors (BP) and from deep-layer to upper-layer neuronal fate; Ntf3 overexpression in neurons increases BP production at the expense of APs, while Ntf3 loss increases layer VI neurons.\",\n      \"method\": \"Genetic epistasis in mouse neocortex: conditional Ntf3 overexpression in neurons, Ntf3 loss-of-function (knockout), comparison with Sip1 mutant phenotype\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with both gain- and loss-of-function in vivo, multiple neuronal layer phenotypes quantified, pathway placement established\",\n      \"pmids\": [\"25085976\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"AAV-delivered Ntf3 gene transfer to the deafened guinea pig cochlea promotes regrowth of peripheral auditory fibers (PAFs) in the basilar membrane area; however, BDNF was more effective than NT-3 in preserving spiral ganglion neurons (SGNs), indicating differential neurotrophin effects in the auditory system.\",\n      \"method\": \"In vivo AAV vector delivery (AAV.Ntf3 vs AAV.BDNF) in deafened guinea pig cochlea; morphological assessment of PAF regrowth and SGN counts at 3 months\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo gene delivery with morphological outcome measures, direct comparison of Ntf3 vs BDNF effects, single lab\",\n      \"pmids\": [\"25726967\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Viral-mediated overexpression of Ntf3 in normal (non-deafened) guinea pig cochlea disrupts peripheral nerve endings and synaptic connections between inner hair cells and auditory nerve fibers, causing hearing threshold shifts, indicating that the level of NT-3 must be tightly regulated for normal cochlear synapse maintenance.\",\n      \"method\": \"Adenovirus and AAV Ntf3 vector inoculation into perilymph/endolymph of normal guinea pig cochlea; ABR threshold measurements and histological evaluation of hair cells, nerve endings, and synaptic ribbons\",\n      \"journal\": \"Molecular therapy. Methods & clinical development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct in vivo loss-of-normal-function experiment with electrophysiological and histological readouts, single lab\",\n      \"pmids\": [\"27525291\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Transcription factor POU3F2 directly binds the NTF3 promoter and positively regulates its transcription during neuronal differentiation; POU3F2 knockdown downregulates NTF3, and recombinant NTF3 rescues neuronal viability and differentiation in both NTF3- and POU3F2-knockdown cells.\",\n      \"method\": \"ChIP-seq, promoter deletion/mutation luciferase reporter assay, siRNA knockdown, rescue with recombinant NTF3 protein, co-immunostaining in developing mouse neurons\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — multiple orthogonal methods (ChIP-seq, promoter mutagenesis with reporter, knockdown rescue) in single lab establishing direct transcriptional regulation\",\n      \"pmids\": [\"29549646\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"A novel missense variant G76R in NTF3, found in two HSCR patients but absent in controls, is postulated to disrupt the NTF3/TrkC signaling pathway required for proper enteric nervous system development; the NTF3/TrkC signaling axis is implicated in neural crest cell migration, proliferation, and differentiation for ENS formation.\",\n      \"method\": \"Mutational screening of NTF3 in HSCR patients and controls; SNP association analysis\",\n      \"journal\": \"Journal of pediatric surgery\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — genetic association/screening study without direct functional validation of the variant; no in vitro or in vivo mechanistic assay performed\",\n      \"pmids\": [\"18639687\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"X-ray crystal structure of NTF3 in complex with an anti-NTF3 Fab revealed that NTF3 contains a flexible loop that becomes ordered upon Fab binding; NTF3 is a cysteine-knot protein that engages the Trk family of receptor tyrosine kinases. Neutralizing antibodies that inhibit NTF3 functional activity were isolated, confirming receptor engagement as the functional mechanism.\",\n      \"method\": \"X-ray crystallography of Fab/NTF3 complex; phage display antibody isolation; functional inhibition assays\",\n      \"journal\": \"SLAS discovery : advancing life sciences R & D\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure with functional antibody validation, but single lab and abstract-level detail on structure\",\n      \"pmids\": [\"39832740\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"miR-21 directly targets NTF3 in cervical cancer cells, as confirmed by dual luciferase reporter assay; overexpression of NTF3 inhibits cell proliferation and migration while promoting apoptosis, and NTF3 involvement in PI3K-AKT and MAPK signaling pathways was identified by transcriptome analysis.\",\n      \"method\": \"Dual luciferase reporter assay (miR-21 targeting NTF3 3'UTR), NTF3 overexpression with viability/migration/apoptosis assays, transcriptome sequencing with KEGG/GO enrichment\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct reporter assay confirming miRNA-target relationship plus functional cellular assays, single lab\",\n      \"pmids\": [\"39828780\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Esketamine (ESK) treatment activates the NTF3/PI3K/AKT signaling pathway in a mouse intracerebral hemorrhage model; AAV-mediated knockdown of NTF3 in the striatum attenuated ESK neuroprotection, and pharmacological PI3K inhibition (LY294002) similarly blocked ESK therapeutic effects, placing NTF3 upstream of PI3K/AKT in ESK-mediated neurorepair.\",\n      \"method\": \"In vivo ICH mouse model; AAV-mediated NTF3 knockdown; PI3K inhibitor (LY294002); Western blotting, immunofluorescence, RNA transcriptome sequencing\",\n      \"journal\": \"CNS neuroscience & therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo genetic (AAV KD) and pharmacological epistasis placing NTF3 upstream of PI3K/AKT, multiple methods, single lab\",\n      \"pmids\": [\"39690816\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NTF3 (neurotrophin-3/NGF-2) is a secreted cysteine-knot neurotrophic factor that activates Trk receptor tyrosine kinases (primarily TrkC, and also TrkB) to promote neuronal survival, differentiation, and synaptic maintenance; its transcription is directly driven by POU3F2 binding to its promoter and by NF-κB during stress, it acts as a retrograde feedback signal from postmitotic neurons to cortical progenitors to control fate-switching, and it signals downstream through PI3K/AKT and MAPK pathways, with its expression level and localization being tightly regulated for normal cochlear synapse integrity.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NTF3 (neurotrophin-3/NGF-2) is a secreted cysteine-knot neurotrophic factor that signals through the Trk family of receptor tyrosine kinases to control neuronal survival, fate, and synaptic integrity [#0, #7]. It promotes survival of dorsal root ganglion and nodose ganglion sensory neurons, defining a neurotrophic activity distinct from NGF [#0], and its functional output depends on Trk receptor engagement, as neutralizing anti-NTF3 antibodies that block receptor binding abolish its activity [#7]. In the developing neocortex NTF3 acts downstream of Sip1 (Zeb2) as a retrograde feedback signal from postmitotic neurons to progenitors, driving the switch from apical to basal progenitors and from deep-layer to upper-layer neuronal fate; gain of NTF3 expands basal progenitors while its loss increases layer VI neurons [#2]. Downstream signaling proceeds through PI3K/AKT, where AAV knockdown and pharmacological PI3K inhibition place NTF3 upstream of this axis in neuroprotection [#9], and transcriptome analysis links it additionally to MAPK signaling [#8]. NTF3 transcription is directly driven by POU3F2 binding to its promoter during neuronal differentiation [#5] and is induced by NF-\\u03baB during cell-suspension stress [#1], while its message is post-transcriptionally repressed by miR-200c and miR-21 [#1, #8]. In the cochlea NTF3 levels must be tightly balanced: gene transfer to deafened cochleae promotes regrowth of peripheral auditory fibers [#3], whereas overexpression in normal cochleae disrupts inner-hair-cell synapses and shifts hearing thresholds [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Established that NTF3 is a bona fide neurotrophic factor with target specificity distinct from NGF, defining its core biological activity.\",\n      \"evidence\": \"In vitro survival assay of DRG and nodose ganglion neurons using conditioned medium from COS cells expressing human NGF-2 cDNA\",\n      \"pmids\": [\"1367285\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor responsible for survival not identified\", \"No downstream signaling pathway dissected\", \"Single lab, single method\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Connected NTF3/TrkC signaling to enteric nervous system development by identifying a candidate missense variant in Hirschsprung disease patients.\",\n      \"evidence\": \"Mutational screening of NTF3 (G76R) in HSCR patients vs controls with SNP association\",\n      \"pmids\": [\"18639687\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No functional validation of the G76R variant in vitro or in vivo\", \"Causality not established\", \"Small patient sample\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Revealed an NF-\\u03baB-driven transcriptional and miRNA-controlled circuit governing NTF3 expression, and showed NTF3 can activate TrkB to confer anoikis resistance in cancer.\",\n      \"evidence\": \"Luciferase reporter (miR-200c/NTF3 3'UTR), NF-\\u03baB inhibition, suspension-induced expression, anoikis assays in TNBC cells\",\n      \"pmids\": [\"23185507\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"TrkB activation shown functionally but direct binding not structurally resolved\", \"Generality beyond TNBC unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Placed NTF3 as a retrograde feedback signal from neurons to progenitors controlling cortical fate-switching, positioning it within a developmental signaling hierarchy below Sip1.\",\n      \"evidence\": \"Genetic epistasis in mouse neocortex with conditional Ntf3 overexpression, knockout, and comparison to Sip1 mutants\",\n      \"pmids\": [\"25085976\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor on progenitors mediating the feedback not defined\", \"Downstream effector pathway in progenitors unresolved\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrated therapeutic potential of NTF3 gene transfer for auditory fiber regrowth while showing neurotrophin-specific differences in spiral ganglion preservation.\",\n      \"evidence\": \"In vivo AAV.Ntf3 vs AAV.BDNF delivery in deafened guinea pig cochlea with morphological assessment\",\n      \"pmids\": [\"25726967\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of differential Ntf3 vs BDNF effects unresolved\", \"Functional hearing recovery not assessed\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed NTF3 dosage must be tightly regulated, as overexpression in healthy cochlea is itself pathogenic for synapses, refining the therapeutic window concept.\",\n      \"evidence\": \"Adeno/AAV Ntf3 inoculation into normal guinea pig cochlea with ABR and histology of synaptic ribbons\",\n      \"pmids\": [\"27525291\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which excess NT-3 disrupts synapses unknown\", \"Receptor signaling threshold not quantified\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identified POU3F2 as a direct transcriptional activator of NTF3 during neuronal differentiation, defining an upstream regulator of its expression.\",\n      \"evidence\": \"ChIP-seq, promoter mutagenesis luciferase reporter, siRNA knockdown, and recombinant NTF3 rescue in mouse neurons\",\n      \"pmids\": [\"29549646\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Other promoter-binding regulators not mapped\", \"In vivo relevance of POU3F2-NTF3 axis untested in animals\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placed NTF3 upstream of PI3K/AKT in neuroprotection, linking its activity to a defined intracellular survival pathway in CNS injury.\",\n      \"evidence\": \"Mouse ICH model with AAV NTF3 knockdown and PI3K inhibitor LY294002, with Western blot and transcriptomics\",\n      \"pmids\": [\"39690816\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor coupling NTF3 to PI3K/AKT in striatum not identified\", \"Direct vs indirect pathway engagement unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Provided structural confirmation that NTF3 is a cysteine-knot protein engaging Trk receptors and that receptor engagement is the functional mechanism, validated by neutralizing antibodies; separately linked NTF3 to PI3K-AKT and MAPK in cancer.\",\n      \"evidence\": \"X-ray crystallography of Fab/NTF3 complex with phage-display antibody isolation and functional inhibition; miR-21/NTF3 luciferase reporter with proliferation/migration/apoptosis assays and transcriptome KEGG/GO analysis\",\n      \"pmids\": [\"39832740\", \"39828780\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Crystal structure of NTF3 bound to a Trk receptor not reported\", \"Receptor specificity (TrkC vs TrkB) in these contexts not resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Which Trk receptor NTF3 engages in each tissue context and how receptor choice dictates the divergent outcomes (progenitor feedback, cochlear synapse maintenance, cancer survival vs suppression) remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of an NTF3-Trk complex\", \"Receptor identity in cortical feedback and cochlear contexts not defined\", \"Context-dependent pro- vs anti-tumor roles mechanistically unexplained\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 7]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [7, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [9, 8]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"NTRK3\", \"NTRK2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}