{"gene":"NPTX2","run_date":"2026-04-29T11:37:57","timeline":{"discoveries":[{"year":2017,"finding":"NPTX2 is expressed presynaptically by pyramidal neurons and regulates excitatory synapses onto parvalbumin (PV) interneurons by controlling postsynaptic GluA4 (AMPA receptor subunit) expression; Nptx2 knockout in a mouse model of AD amyloidosis reduces GluA4 expression, disrupts network rhythmicity, and increases pyramidal neuron excitability.","method":"Nptx2 knockout mouse model, electrophysiology, immunohistochemistry, postmortem human AD cortex analysis","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (KO mouse, electrophysiology, human postmortem validation), widely replicated concept","pmids":["28440221"],"is_preprint":false},{"year":2023,"finding":"Secreted NPTX2 binds complement component C1q directly, thereby inhibiting complement activity in the brain; NPTX2-deficient mice show increased C1q-dependent microglial synapse engulfment and excitatory synapse loss, and AAV-mediated neuronal NPTX2 overexpression rescues these phenotypes.","method":"Co-immunoprecipitation (NPTX2-C1q complex identified in CSF), Nptx2 knockout mouse, AAV overexpression, synapse engulfment assays, neuroinflammation culture model, aged TauP301S mice","journal":"Science translational medicine","confidence":"High","confidence_rationale":"Tier 1–2 — direct binding identified, KO phenotype, rescue by AAV overexpression, human CSF validation, multiple orthogonal methods","pmids":["36989373"],"is_preprint":false},{"year":2021,"finding":"NPTX2 function requires activity-dependent exocytosis and dynamic shedding at synapses; behavior-linked NPTX2 trafficking is abolished by mutations that disrupt select activity-dependent plasticity mechanisms of excitatory neurons. NPTX2 loss of function impairs parvalbumin interneuron adaptive responses to behavioral stress.","method":"NPTX2 trafficking assays, site-directed mutagenesis of plasticity-related domains, Nptx2 loss-of-function mouse model, behavioral stress paradigms, electrophysiology","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1–2 — mutagenesis plus KO with defined cellular and behavioral phenotypes, multiple methods","pmids":["34818031"],"is_preprint":false},{"year":2019,"finding":"In the dorsal hippocampus, retrieval-driven upregulation of NPTX2 recruits GluA1-AMPA receptors via its pentraxin (PTX) domain, enhancing excitatory synaptic transmission and facilitating extinction of cocaine-associated context memory; overexpressing the carboxyl cytoplasmic tail of GluA1 blocked this effect.","method":"Ribosomal tagging (translational profiling), electrophysiology, neuronal tracing, doxycycline-dependent activity marking, dominant-negative GluA1 overexpression, hippocampal Nptx2 manipulation in mice","journal":"Biological psychiatry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods, specific domain identified, bidirectional manipulation with defined synaptic and behavioral readout","pmids":["31836174"],"is_preprint":false},{"year":2024,"finding":"TDP-43 binds the 3′ UTR of NPTX2 mRNA to regulate NPTX2 protein levels; loss of nuclear TDP-43 causes NPTX2 misaccumulation in neurons, which is neurotoxic, and correcting NPTX2 misregulation partially rescues neurons from TDP-43-induced neurodegeneration.","method":"iPSC-derived neural network model (iNets), single-cell transcriptomics, TDP-43 overexpression/loss-of-function, NPTX2 overexpression and correction, patient ALS/FTLD tissue analysis","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1–2 — direct TDP-43 binding to NPTX2 3′ UTR demonstrated, rescue experiments, human tissue validation, multiple orthogonal methods","pmids":["38355792"],"is_preprint":false},{"year":2018,"finding":"Hippocampus-specific NPTX2 expression regulates anxiety behavior and hippocampal cell proliferation; knockout of Nptx2 in the hippocampus (but not the amygdala) increases anxiety and glucocorticoid receptor target gene expression after stress, while hippocampal overexpression alleviates stress-induced anxiety and reverses these gene expression changes.","method":"Region-specific knockout and overexpression mouse models, behavioral anxiety tests, adult neurogenesis assessment, glucocorticoid-related gene expression analysis","journal":"Neuropsychopharmacology","confidence":"High","confidence_rationale":"Tier 2 — bidirectional manipulation (KO and OE), region-specific dissection, multiple behavioral and molecular readouts","pmids":["29844474"],"is_preprint":false},{"year":2019,"finding":"NPTX2 physically interacts with Frizzled receptor FZD6 on colorectal cancer cells to activate the Wnt/β-catenin signaling pathway, promoting β-catenin nuclear translocation, upregulating MYC and cyclin D1, and driving cancer cell proliferation and metastasis; FZD6 siRNA knockdown reverses these effects.","method":"Co-immunoprecipitation (NPTX2-FZD6 interaction), siRNA knockdown, in vitro proliferation/invasion assays, in vivo xenograft, western blot for pathway components","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2–3 — direct binding shown by Co-IP, functional rescue by FZD6 KD, but single lab and cancer context differs from neuronal function","pmids":["30833544"],"is_preprint":false},{"year":2025,"finding":"Overexpression of NPTX2 in lateral entorhinal cortex (LEC) neurons of learning-impaired aged rats enhances feedforward inhibition of dentate gyrus granule cells by fast-spiking interneurons and improves spatial memory performance, establishing NPTX2's role in stabilizing excitatory inputs onto fast-spiking inhibitory interneurons.","method":"AAV-mediated NPTX2 overexpression in rat LEC, in vivo electrophysiology (feedforward inhibition), spatial memory behavioral testing","journal":"Progress in neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 — direct overexpression with electrophysiological and behavioral readout, single lab","pmids":["40057261"],"is_preprint":false},{"year":2023,"finding":"NPTX2 knockout mice exhibit disrupted circadian onset, increased activity during sleep phase, sleep fragmentation, altered vigilance state transitions, shifts in EEG spectral power, and decreased sleep spindles, demonstrating that NPTX2 loss of function directly causes sleep and circadian rhythm disruption independently of orexin.","method":"Nptx2 KO mouse, sleep EEG/polysomnography, circadian activity monitoring, orexin immunostaining","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — KO with multiple electrophysiological and behavioral readouts, preprint, single lab","pmids":["37808783"],"is_preprint":true},{"year":2023,"finding":"NPTX2 in cutaneous squamous cell carcinoma (cSCC) physically interacts with METTL3, increases METTL3 expression, and promotes METTL3-mediated N6-methyladenosine (m6A) modification of SNAIL mRNA, thereby facilitating epithelial-mesenchymal transition; METTL3 knockdown reversed NPTX2 overexpression effects.","method":"Co-immunoprecipitation (NPTX2-METTL3), m6A assays, METTL3 knockdown, in vitro proliferation/invasion/EMT assays, in vivo xenograft","journal":"The Journal of investigative dermatology","confidence":"Low","confidence_rationale":"Tier 3 — single Co-IP, cancer context potentially unrelated to neuronal function of NPTX2, single lab","pmids":["36638907"],"is_preprint":false},{"year":2025,"finding":"In dentate gyrus engram neurons, NPTX2 (via its AMPA receptor binding domain) facilitates perisomatic inhibition of Npas4+ ensemble neurons by parvalbumin interneurons, preventing fear memory overgeneralization; overexpression of the AMPAR-binding domain of NPTX2 in Npas4+ neurons rescued memory imprecision in aged mice.","method":"Engram-specific NPTX2 depletion/overexpression, chemogenetic activation of PV interneurons, contextual fear memory behavioral paradigms in aged mice","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — domain-specific rescue, bidirectional manipulation, defined circuit and behavioral readout; preprint","pmids":["41000823"],"is_preprint":true},{"year":2020,"finding":"In a Parkinson's disease model, HOTAIR lncRNA sponges miR-221-3p to elevate NPTX2 expression; elevated NPTX2 reduces dopaminergic neuron viability and enhances autophagy both in vitro and in vivo.","method":"RIP assay, dual-luciferase reporter assay, CCK-8 viability assay, Western blot for autophagy markers, MPTP mouse model and MPP+ cell model","journal":"Aging","confidence":"Low","confidence_rationale":"Tier 3 — ceRNA mechanism shown, but functional consequence of NPTX2 elevation not directly tested with NPTX2-specific rescue, single lab","pmids":["32396526"],"is_preprint":false},{"year":1995,"finding":"NPTX2 (neuronal pentraxin II) was identified as a member of the pentraxin family expressed in brain, testis, pancreas, liver, heart, and skeletal muscle; it shares 54% amino acid identity with rat neuronal pentraxin I (NPTX1) and contains potential N-linked glycosylation sites; the gene is 11 kb, contains four introns, and is localized to chromosome 7q21.3-q22.1.","method":"cDNA cloning, genomic sequencing, Northern blot analysis, chromosomal localization","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 1 — foundational cloning and characterization paper, direct molecular characterization","pmids":["8530029"],"is_preprint":false}],"current_model":"NPTX2 is a secreted neuronal pentraxin and immediate-early gene expressed presynaptically by excitatory pyramidal neurons that drives GluA4-containing AMPA receptor clustering at excitatory synapses onto parvalbumin fast-spiking interneurons to maintain excitatory/inhibitory balance; it directly binds and inhibits complement C1q to restrain microglial synapse elimination; its activity-dependent exocytosis and dynamic synaptic shedding are required for adaptive circuit responses to behavioral stress; its mRNA is regulated by TDP-43 binding to its 3′ UTR; and its loss of function disrupts network rhythmicity, sleep/circadian homeostasis, and hippocampal memory, while reduced CSF NPTX2 is a downstream consequence of synaptic failure in Alzheimer's disease and related neurodegenerative conditions."},"narrative":{"teleology":[{"year":1995,"claim":"Identification of NPTX2 as a brain-expressed pentraxin family member established the gene's molecular identity and tissue distribution, opening the question of its neuronal function.","evidence":"cDNA cloning, Northern blot, genomic sequencing, and chromosomal mapping in human tissues","pmids":["8530029"],"confidence":"High","gaps":["No functional role determined","No synaptic localization or binding partners identified","Pentraxin domain function unknown"]},{"year":2017,"claim":"Demonstration that NPTX2 is expressed presynaptically by pyramidal neurons and controls postsynaptic GluA4-AMPA receptor levels on parvalbumin interneurons resolved its primary synaptic function and linked its loss to network hyperexcitability and disrupted rhythmicity in an AD amyloidosis model.","evidence":"Nptx2 knockout mouse crossed with amyloid model, electrophysiology, immunohistochemistry, human postmortem cortex validation","pmids":["28440221"],"confidence":"High","gaps":["Mechanism of NPTX2-mediated GluA4 clustering not defined at structural level","Whether NPTX2 loss is cause or consequence of AD network dysfunction unclear","Contributions of other neuronal pentraxins (NPTX1, NPTXR) not separated"]},{"year":2018,"claim":"Region-specific hippocampal knockout and overexpression revealed that NPTX2 regulates anxiety behavior and stress-related glucocorticoid signaling, extending its role beyond synapse organization to behavioral homeostasis.","evidence":"Hippocampus-specific Nptx2 KO and OE in mice, behavioral anxiety tests, glucocorticoid target gene expression, adult neurogenesis assessment","pmids":["29844474"],"confidence":"High","gaps":["How NPTX2's synaptic function translates to glucocorticoid receptor gene regulation is unknown","Amygdala-independent mechanism not fully characterized"]},{"year":2019,"claim":"Identification that retrieval-induced NPTX2 recruits GluA1-AMPA receptors via its pentraxin domain to facilitate extinction of cocaine-associated memory demonstrated domain-specific receptor recruitment in a memory updating context.","evidence":"Ribosomal tagging, electrophysiology, dominant-negative GluA1 overexpression, hippocampal NPTX2 manipulation in mice","pmids":["31836174"],"confidence":"High","gaps":["Whether GluA1 versus GluA4 recruitment reflects circuit-specific differences or stimulus-specific differences unresolved","Structural basis of pentraxin domain–AMPAR interaction unknown"]},{"year":2021,"claim":"Demonstration that NPTX2 requires activity-dependent exocytosis and dynamic synaptic shedding — abolished by specific plasticity-disrupting mutations — established the regulated trafficking mechanism underlying its trans-synaptic signaling.","evidence":"NPTX2 trafficking assays, site-directed mutagenesis, Nptx2 loss-of-function mouse, behavioral stress paradigms, electrophysiology","pmids":["34818031"],"confidence":"High","gaps":["Identity of the protease(s) mediating NPTX2 ectodomain shedding not determined","Exact activity-dependent signaling cascade triggering exocytosis not delineated"]},{"year":2023,"claim":"Discovery that secreted NPTX2 directly binds complement C1q and restrains microglial synapse engulfment revealed a second, complement-inhibitory mechanism by which NPTX2 protects excitatory synapses, with AAV rescue confirming causality.","evidence":"Co-IP of NPTX2–C1q complex in CSF, Nptx2 KO mouse, AAV overexpression rescue, synapse engulfment assays, aged TauP301S mice","pmids":["36989373"],"confidence":"High","gaps":["Binding interface between NPTX2 and C1q not structurally resolved","Whether NPTX2–C1q interaction is relevant at inhibitory synapses untested","Relative contributions of AMPAR-clustering versus complement-inhibition to synapse protection not quantified"]},{"year":2023,"claim":"NPTX2 knockout mice show sleep fragmentation, disrupted circadian onset, altered EEG spectral power, and decreased sleep spindles independent of orexin, establishing a direct role for NPTX2 in sleep/circadian regulation.","evidence":"Nptx2 KO mouse, sleep EEG/polysomnography, circadian activity monitoring (preprint)","pmids":["37808783"],"confidence":"Medium","gaps":["Preprint not yet peer-reviewed","Circuit mechanism linking NPTX2 loss to sleep architecture disruption not identified","Interaction with known circadian clock genes untested"]},{"year":2024,"claim":"Identification of TDP-43 as a direct regulator of NPTX2 mRNA via 3′ UTR binding connected NPTX2 misregulation to ALS/FTLD neurodegeneration, showing that TDP-43 loss causes neurotoxic NPTX2 misaccumulation and that correcting NPTX2 levels partially rescues TDP-43-induced neurodegeneration.","evidence":"iPSC-derived neural networks, single-cell transcriptomics, TDP-43 manipulation, NPTX2 overexpression/correction, human ALS/FTLD tissue validation","pmids":["38355792"],"confidence":"High","gaps":["Mechanism of NPTX2-induced neurotoxicity upon misaccumulation not defined","Whether TDP-43 regulation of NPTX2 is direct or involves intermediary RNA-binding events needs further dissection"]},{"year":2025,"claim":"Engram-specific manipulation showed NPTX2's AMPAR-binding domain facilitates perisomatic inhibition of dentate gyrus ensemble neurons by PV interneurons, preventing fear memory overgeneralization in aged mice and establishing a memory-precision function.","evidence":"Engram-specific NPTX2 depletion/overexpression, chemogenetic PV interneuron activation, contextual fear memory paradigms (preprint)","pmids":["41000823"],"confidence":"Medium","gaps":["Preprint not yet peer-reviewed","Whether the memory precision role extends beyond fear conditioning untested","Contribution of NPTX2's complement-inhibitory function to engram stability not assessed"]},{"year":null,"claim":"Major open questions include the structural basis of NPTX2's pentraxin domain interactions with AMPAR subunits and C1q, the protease(s) responsible for synaptic shedding, the mechanism by which NPTX2 misaccumulation is neurotoxic, and how its AMPAR-clustering and complement-inhibitory functions are coordinated at the synapse.","evidence":"","pmids":[],"confidence":"High","gaps":["No crystal or cryo-EM structure of NPTX2 or its complexes","Shedding protease identity unknown","Relative in vivo contributions of dual mechanisms not quantified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,3,10]},{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,1,3]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[1,2,12]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2,3]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[0,2,3,7,10]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1]}],"complexes":[],"partners":["GRIA4","GRIA1","C1Q","TARDBP"],"other_free_text":[]},"mechanistic_narrative":"NPTX2 is a secreted neuronal pentraxin and immediate-early gene that functions as a trans-synaptic organizer of excitatory drive onto fast-spiking parvalbumin interneurons, thereby maintaining excitatory–inhibitory balance, network rhythmicity, and memory precision. Expressed presynaptically by excitatory pyramidal neurons, NPTX2 clusters GluA4-containing AMPA receptors at postsynaptic sites on parvalbumin interneurons through its pentraxin domain, and its activity-dependent exocytosis and synaptic shedding are required for adaptive circuit responses to behavioral stress [PMID:28440221, PMID:34818031, PMID:40057261, PMID:41000823]. NPTX2 also directly binds complement C1q to inhibit complement-mediated microglial synapse elimination, and its loss leads to excessive C1q-dependent excitatory synapse engulfment [PMID:36989373]. TDP-43 regulates NPTX2 protein levels by binding the 3′ UTR of NPTX2 mRNA; loss of nuclear TDP-43 causes neurotoxic NPTX2 misaccumulation, linking NPTX2 dysregulation to ALS/FTLD neurodegeneration [PMID:38355792]."},"prefetch_data":{"uniprot":{"accession":"P47972","full_name":"Neuronal pentraxin-2","aliases":["Neuronal pentraxin II","NP-II"],"length_aa":431,"mass_kda":47.0,"function":"Likely to play role in the modification of cellular properties that underlie long-term plasticity. Binds to agar matrix in a calcium-dependent manner (By similarity)","subcellular_location":"Secreted","url":"https://www.uniprot.org/uniprotkb/P47972/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NPTX2","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/NPTX2","total_profiled":1310},"omim":[{"mim_id":"609474","title":"NEURONAL PENTRAXIN RECEPTOR; NPTXR","url":"https://www.omim.org/entry/609474"},{"mim_id":"605078","title":"TAR DNA-BINDING PROTEIN; TARDBP","url":"https://www.omim.org/entry/605078"},{"mim_id":"602367","title":"NEURONAL PENTRAXIN 1; NPTX1","url":"https://www.omim.org/entry/602367"},{"mim_id":"602358","title":"HYPOCRETIN; HCRT","url":"https://www.omim.org/entry/602358"},{"mim_id":"600750","title":"NEURONAL PENTRAXIN 2; NPTX2","url":"https://www.omim.org/entry/600750"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Actin filaments","reliability":"Approved"},{"location":"Centrosome","reliability":"Additional"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"pituitary gland","ntpm":200.0}],"url":"https://www.proteinatlas.org/search/NPTX2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P47972","domains":[{"cath_id":"2.60.120.200","chopping":"224-428","consensus_level":"high","plddt":95.1396,"start":224,"end":428},{"cath_id":"1.20.5","chopping":"161-217","consensus_level":"medium","plddt":83.7842,"start":161,"end":217}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P47972","model_url":"https://alphafold.ebi.ac.uk/files/AF-P47972-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P47972-F1-predicted_aligned_error_v6.png","plddt_mean":80.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NPTX2","jax_strain_url":"https://www.jax.org/strain/search?query=NPTX2"},"sequence":{"accession":"P47972","fasta_url":"https://rest.uniprot.org/uniprotkb/P47972.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P47972/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P47972"}},"corpus_meta":[{"pmid":"28440221","id":"PMC_28440221","title":"NPTX2 and cognitive dysfunction in Alzheimer's Disease.","date":"2017","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/28440221","citation_count":207,"is_preprint":false},{"pmid":"36989373","id":"PMC_36989373","title":"The neuronal pentraxin Nptx2 regulates complement activity and restrains microglia-mediated synapse loss in neurodegeneration.","date":"2023","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/36989373","citation_count":109,"is_preprint":false},{"pmid":"8530029","id":"PMC_8530029","title":"Human neuronal pentraxin II (NPTX2): conservation, genomic structure, and chromosomal localization.","date":"1995","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/8530029","citation_count":92,"is_preprint":false},{"pmid":"30833544","id":"PMC_30833544","title":"NPTX2 promotes colorectal cancer growth and liver metastasis by the activation of the canonical Wnt/β-catenin pathway via FZD6.","date":"2019","source":"Cell death & 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neurology","url":"https://pubmed.ncbi.nlm.nih.gov/38566855","citation_count":8,"is_preprint":false},{"pmid":"36638907","id":"PMC_36638907","title":"NPTX2 Promotes Epithelial-Mesenchymal Transition in Cutaneous Squamous Cell Carcinoma through METTL3-Mediated N6-Methyladenosine Methylation of SNAIL.","date":"2023","source":"The Journal of investigative dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/36638907","citation_count":6,"is_preprint":false},{"pmid":"35482070","id":"PMC_35482070","title":"Neuronal pentraxin-2 (NPTX2) serum levels during an acute psychotic episode in patients with schizophrenia.","date":"2022","source":"Psychopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/35482070","citation_count":6,"is_preprint":false},{"pmid":"35310907","id":"PMC_35310907","title":"miR-1251-5p Overexpression Inhibits Proliferation, Migration, and Immune Escape in Clear Cell Renal Cell Carcinoma by Targeting NPTX2.","date":"2022","source":"Journal of 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treatment","url":"https://pubmed.ncbi.nlm.nih.gov/38741580","citation_count":2,"is_preprint":false},{"pmid":"37808783","id":"PMC_37808783","title":"Sleep and circadian rhythm disruption by NPTX2 loss of function.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/37808783","citation_count":1,"is_preprint":false},{"pmid":"41272913","id":"PMC_41272913","title":"Cerebrospinal fluid NPTX2 and [18F]FDG PET track serotonergic vulnerability to neurodegeneration in prodromal Alzheimer's disease.","date":"2025","source":"Alzheimer's research & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/41272913","citation_count":1,"is_preprint":false},{"pmid":"32801587","id":"PMC_32801587","title":"Determination of epigenetic age through DNA methylation of NPTX2 gene using buccal scrapes: A pilot study.","date":"2020","source":"Journal of forensic dental 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disease","date":"2024-07-23","source":"bioRxiv","url":"https://doi.org/10.1101/2024.07.22.604680","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":28855,"output_tokens":3330,"usd":0.068257},"stage2":{"model":"claude-opus-4-6","input_tokens":6717,"output_tokens":2626,"usd":0.148852},"total_usd":0.217109,"stage1_batch_id":"msgbatch_012ZiiCUBfB62NCTQd4Bk1Jo","stage2_batch_id":"msgbatch_01Xuqq9aUHoQouS7UVGZNStZ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"NPTX2 is expressed presynaptically by pyramidal neurons and regulates excitatory synapses onto parvalbumin (PV) interneurons by controlling postsynaptic GluA4 (AMPA receptor subunit) expression; Nptx2 knockout in a mouse model of AD amyloidosis reduces GluA4 expression, disrupts network rhythmicity, and increases pyramidal neuron excitability.\",\n      \"method\": \"Nptx2 knockout mouse model, electrophysiology, immunohistochemistry, postmortem human AD cortex analysis\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (KO mouse, electrophysiology, human postmortem validation), widely replicated concept\",\n      \"pmids\": [\"28440221\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Secreted NPTX2 binds complement component C1q directly, thereby inhibiting complement activity in the brain; NPTX2-deficient mice show increased C1q-dependent microglial synapse engulfment and excitatory synapse loss, and AAV-mediated neuronal NPTX2 overexpression rescues these phenotypes.\",\n      \"method\": \"Co-immunoprecipitation (NPTX2-C1q complex identified in CSF), Nptx2 knockout mouse, AAV overexpression, synapse engulfment assays, neuroinflammation culture model, aged TauP301S mice\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct binding identified, KO phenotype, rescue by AAV overexpression, human CSF validation, multiple orthogonal methods\",\n      \"pmids\": [\"36989373\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"NPTX2 function requires activity-dependent exocytosis and dynamic shedding at synapses; behavior-linked NPTX2 trafficking is abolished by mutations that disrupt select activity-dependent plasticity mechanisms of excitatory neurons. NPTX2 loss of function impairs parvalbumin interneuron adaptive responses to behavioral stress.\",\n      \"method\": \"NPTX2 trafficking assays, site-directed mutagenesis of plasticity-related domains, Nptx2 loss-of-function mouse model, behavioral stress paradigms, electrophysiology\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — mutagenesis plus KO with defined cellular and behavioral phenotypes, multiple methods\",\n      \"pmids\": [\"34818031\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In the dorsal hippocampus, retrieval-driven upregulation of NPTX2 recruits GluA1-AMPA receptors via its pentraxin (PTX) domain, enhancing excitatory synaptic transmission and facilitating extinction of cocaine-associated context memory; overexpressing the carboxyl cytoplasmic tail of GluA1 blocked this effect.\",\n      \"method\": \"Ribosomal tagging (translational profiling), electrophysiology, neuronal tracing, doxycycline-dependent activity marking, dominant-negative GluA1 overexpression, hippocampal Nptx2 manipulation in mice\",\n      \"journal\": \"Biological psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, specific domain identified, bidirectional manipulation with defined synaptic and behavioral readout\",\n      \"pmids\": [\"31836174\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TDP-43 binds the 3′ UTR of NPTX2 mRNA to regulate NPTX2 protein levels; loss of nuclear TDP-43 causes NPTX2 misaccumulation in neurons, which is neurotoxic, and correcting NPTX2 misregulation partially rescues neurons from TDP-43-induced neurodegeneration.\",\n      \"method\": \"iPSC-derived neural network model (iNets), single-cell transcriptomics, TDP-43 overexpression/loss-of-function, NPTX2 overexpression and correction, patient ALS/FTLD tissue analysis\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct TDP-43 binding to NPTX2 3′ UTR demonstrated, rescue experiments, human tissue validation, multiple orthogonal methods\",\n      \"pmids\": [\"38355792\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Hippocampus-specific NPTX2 expression regulates anxiety behavior and hippocampal cell proliferation; knockout of Nptx2 in the hippocampus (but not the amygdala) increases anxiety and glucocorticoid receptor target gene expression after stress, while hippocampal overexpression alleviates stress-induced anxiety and reverses these gene expression changes.\",\n      \"method\": \"Region-specific knockout and overexpression mouse models, behavioral anxiety tests, adult neurogenesis assessment, glucocorticoid-related gene expression analysis\",\n      \"journal\": \"Neuropsychopharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — bidirectional manipulation (KO and OE), region-specific dissection, multiple behavioral and molecular readouts\",\n      \"pmids\": [\"29844474\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"NPTX2 physically interacts with Frizzled receptor FZD6 on colorectal cancer cells to activate the Wnt/β-catenin signaling pathway, promoting β-catenin nuclear translocation, upregulating MYC and cyclin D1, and driving cancer cell proliferation and metastasis; FZD6 siRNA knockdown reverses these effects.\",\n      \"method\": \"Co-immunoprecipitation (NPTX2-FZD6 interaction), siRNA knockdown, in vitro proliferation/invasion assays, in vivo xenograft, western blot for pathway components\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — direct binding shown by Co-IP, functional rescue by FZD6 KD, but single lab and cancer context differs from neuronal function\",\n      \"pmids\": [\"30833544\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Overexpression of NPTX2 in lateral entorhinal cortex (LEC) neurons of learning-impaired aged rats enhances feedforward inhibition of dentate gyrus granule cells by fast-spiking interneurons and improves spatial memory performance, establishing NPTX2's role in stabilizing excitatory inputs onto fast-spiking inhibitory interneurons.\",\n      \"method\": \"AAV-mediated NPTX2 overexpression in rat LEC, in vivo electrophysiology (feedforward inhibition), spatial memory behavioral testing\",\n      \"journal\": \"Progress in neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct overexpression with electrophysiological and behavioral readout, single lab\",\n      \"pmids\": [\"40057261\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NPTX2 knockout mice exhibit disrupted circadian onset, increased activity during sleep phase, sleep fragmentation, altered vigilance state transitions, shifts in EEG spectral power, and decreased sleep spindles, demonstrating that NPTX2 loss of function directly causes sleep and circadian rhythm disruption independently of orexin.\",\n      \"method\": \"Nptx2 KO mouse, sleep EEG/polysomnography, circadian activity monitoring, orexin immunostaining\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KO with multiple electrophysiological and behavioral readouts, preprint, single lab\",\n      \"pmids\": [\"37808783\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NPTX2 in cutaneous squamous cell carcinoma (cSCC) physically interacts with METTL3, increases METTL3 expression, and promotes METTL3-mediated N6-methyladenosine (m6A) modification of SNAIL mRNA, thereby facilitating epithelial-mesenchymal transition; METTL3 knockdown reversed NPTX2 overexpression effects.\",\n      \"method\": \"Co-immunoprecipitation (NPTX2-METTL3), m6A assays, METTL3 knockdown, in vitro proliferation/invasion/EMT assays, in vivo xenograft\",\n      \"journal\": \"The Journal of investigative dermatology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP, cancer context potentially unrelated to neuronal function of NPTX2, single lab\",\n      \"pmids\": [\"36638907\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In dentate gyrus engram neurons, NPTX2 (via its AMPA receptor binding domain) facilitates perisomatic inhibition of Npas4+ ensemble neurons by parvalbumin interneurons, preventing fear memory overgeneralization; overexpression of the AMPAR-binding domain of NPTX2 in Npas4+ neurons rescued memory imprecision in aged mice.\",\n      \"method\": \"Engram-specific NPTX2 depletion/overexpression, chemogenetic activation of PV interneurons, contextual fear memory behavioral paradigms in aged mice\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — domain-specific rescue, bidirectional manipulation, defined circuit and behavioral readout; preprint\",\n      \"pmids\": [\"41000823\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In a Parkinson's disease model, HOTAIR lncRNA sponges miR-221-3p to elevate NPTX2 expression; elevated NPTX2 reduces dopaminergic neuron viability and enhances autophagy both in vitro and in vivo.\",\n      \"method\": \"RIP assay, dual-luciferase reporter assay, CCK-8 viability assay, Western blot for autophagy markers, MPTP mouse model and MPP+ cell model\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — ceRNA mechanism shown, but functional consequence of NPTX2 elevation not directly tested with NPTX2-specific rescue, single lab\",\n      \"pmids\": [\"32396526\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"NPTX2 (neuronal pentraxin II) was identified as a member of the pentraxin family expressed in brain, testis, pancreas, liver, heart, and skeletal muscle; it shares 54% amino acid identity with rat neuronal pentraxin I (NPTX1) and contains potential N-linked glycosylation sites; the gene is 11 kb, contains four introns, and is localized to chromosome 7q21.3-q22.1.\",\n      \"method\": \"cDNA cloning, genomic sequencing, Northern blot analysis, chromosomal localization\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — foundational cloning and characterization paper, direct molecular characterization\",\n      \"pmids\": [\"8530029\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NPTX2 is a secreted neuronal pentraxin and immediate-early gene expressed presynaptically by excitatory pyramidal neurons that drives GluA4-containing AMPA receptor clustering at excitatory synapses onto parvalbumin fast-spiking interneurons to maintain excitatory/inhibitory balance; it directly binds and inhibits complement C1q to restrain microglial synapse elimination; its activity-dependent exocytosis and dynamic synaptic shedding are required for adaptive circuit responses to behavioral stress; its mRNA is regulated by TDP-43 binding to its 3′ UTR; and its loss of function disrupts network rhythmicity, sleep/circadian homeostasis, and hippocampal memory, while reduced CSF NPTX2 is a downstream consequence of synaptic failure in Alzheimer's disease and related neurodegenerative conditions.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"NPTX2 is a secreted neuronal pentraxin and immediate-early gene that functions as a trans-synaptic organizer of excitatory drive onto fast-spiking parvalbumin interneurons, thereby maintaining excitatory–inhibitory balance, network rhythmicity, and memory precision. Expressed presynaptically by excitatory pyramidal neurons, NPTX2 clusters GluA4-containing AMPA receptors at postsynaptic sites on parvalbumin interneurons through its pentraxin domain, and its activity-dependent exocytosis and synaptic shedding are required for adaptive circuit responses to behavioral stress [PMID:28440221, PMID:34818031, PMID:40057261, PMID:41000823]. NPTX2 also directly binds complement C1q to inhibit complement-mediated microglial synapse elimination, and its loss leads to excessive C1q-dependent excitatory synapse engulfment [PMID:36989373]. TDP-43 regulates NPTX2 protein levels by binding the 3′ UTR of NPTX2 mRNA; loss of nuclear TDP-43 causes neurotoxic NPTX2 misaccumulation, linking NPTX2 dysregulation to ALS/FTLD neurodegeneration [PMID:38355792].\",\n  \"teleology\": [\n    {\n      \"year\": 1995,\n      \"claim\": \"Identification of NPTX2 as a brain-expressed pentraxin family member established the gene's molecular identity and tissue distribution, opening the question of its neuronal function.\",\n      \"evidence\": \"cDNA cloning, Northern blot, genomic sequencing, and chromosomal mapping in human tissues\",\n      \"pmids\": [\"8530029\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No functional role determined\", \"No synaptic localization or binding partners identified\", \"Pentraxin domain function unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstration that NPTX2 is expressed presynaptically by pyramidal neurons and controls postsynaptic GluA4-AMPA receptor levels on parvalbumin interneurons resolved its primary synaptic function and linked its loss to network hyperexcitability and disrupted rhythmicity in an AD amyloidosis model.\",\n      \"evidence\": \"Nptx2 knockout mouse crossed with amyloid model, electrophysiology, immunohistochemistry, human postmortem cortex validation\",\n      \"pmids\": [\"28440221\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of NPTX2-mediated GluA4 clustering not defined at structural level\", \"Whether NPTX2 loss is cause or consequence of AD network dysfunction unclear\", \"Contributions of other neuronal pentraxins (NPTX1, NPTXR) not separated\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Region-specific hippocampal knockout and overexpression revealed that NPTX2 regulates anxiety behavior and stress-related glucocorticoid signaling, extending its role beyond synapse organization to behavioral homeostasis.\",\n      \"evidence\": \"Hippocampus-specific Nptx2 KO and OE in mice, behavioral anxiety tests, glucocorticoid target gene expression, adult neurogenesis assessment\",\n      \"pmids\": [\"29844474\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How NPTX2's synaptic function translates to glucocorticoid receptor gene regulation is unknown\", \"Amygdala-independent mechanism not fully characterized\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identification that retrieval-induced NPTX2 recruits GluA1-AMPA receptors via its pentraxin domain to facilitate extinction of cocaine-associated memory demonstrated domain-specific receptor recruitment in a memory updating context.\",\n      \"evidence\": \"Ribosomal tagging, electrophysiology, dominant-negative GluA1 overexpression, hippocampal NPTX2 manipulation in mice\",\n      \"pmids\": [\"31836174\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether GluA1 versus GluA4 recruitment reflects circuit-specific differences or stimulus-specific differences unresolved\", \"Structural basis of pentraxin domain–AMPAR interaction unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstration that NPTX2 requires activity-dependent exocytosis and dynamic synaptic shedding — abolished by specific plasticity-disrupting mutations — established the regulated trafficking mechanism underlying its trans-synaptic signaling.\",\n      \"evidence\": \"NPTX2 trafficking assays, site-directed mutagenesis, Nptx2 loss-of-function mouse, behavioral stress paradigms, electrophysiology\",\n      \"pmids\": [\"34818031\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the protease(s) mediating NPTX2 ectodomain shedding not determined\", \"Exact activity-dependent signaling cascade triggering exocytosis not delineated\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Discovery that secreted NPTX2 directly binds complement C1q and restrains microglial synapse engulfment revealed a second, complement-inhibitory mechanism by which NPTX2 protects excitatory synapses, with AAV rescue confirming causality.\",\n      \"evidence\": \"Co-IP of NPTX2–C1q complex in CSF, Nptx2 KO mouse, AAV overexpression rescue, synapse engulfment assays, aged TauP301S mice\",\n      \"pmids\": [\"36989373\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Binding interface between NPTX2 and C1q not structurally resolved\", \"Whether NPTX2–C1q interaction is relevant at inhibitory synapses untested\", \"Relative contributions of AMPAR-clustering versus complement-inhibition to synapse protection not quantified\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"NPTX2 knockout mice show sleep fragmentation, disrupted circadian onset, altered EEG spectral power, and decreased sleep spindles independent of orexin, establishing a direct role for NPTX2 in sleep/circadian regulation.\",\n      \"evidence\": \"Nptx2 KO mouse, sleep EEG/polysomnography, circadian activity monitoring (preprint)\",\n      \"pmids\": [\"37808783\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not yet peer-reviewed\", \"Circuit mechanism linking NPTX2 loss to sleep architecture disruption not identified\", \"Interaction with known circadian clock genes untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identification of TDP-43 as a direct regulator of NPTX2 mRNA via 3′ UTR binding connected NPTX2 misregulation to ALS/FTLD neurodegeneration, showing that TDP-43 loss causes neurotoxic NPTX2 misaccumulation and that correcting NPTX2 levels partially rescues TDP-43-induced neurodegeneration.\",\n      \"evidence\": \"iPSC-derived neural networks, single-cell transcriptomics, TDP-43 manipulation, NPTX2 overexpression/correction, human ALS/FTLD tissue validation\",\n      \"pmids\": [\"38355792\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of NPTX2-induced neurotoxicity upon misaccumulation not defined\", \"Whether TDP-43 regulation of NPTX2 is direct or involves intermediary RNA-binding events needs further dissection\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Engram-specific manipulation showed NPTX2's AMPAR-binding domain facilitates perisomatic inhibition of dentate gyrus ensemble neurons by PV interneurons, preventing fear memory overgeneralization in aged mice and establishing a memory-precision function.\",\n      \"evidence\": \"Engram-specific NPTX2 depletion/overexpression, chemogenetic PV interneuron activation, contextual fear memory paradigms (preprint)\",\n      \"pmids\": [\"41000823\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not yet peer-reviewed\", \"Whether the memory precision role extends beyond fear conditioning untested\", \"Contribution of NPTX2's complement-inhibitory function to engram stability not assessed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Major open questions include the structural basis of NPTX2's pentraxin domain interactions with AMPAR subunits and C1q, the protease(s) responsible for synaptic shedding, the mechanism by which NPTX2 misaccumulation is neurotoxic, and how its AMPAR-clustering and complement-inhibitory functions are coordinated at the synapse.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal or cryo-EM structure of NPTX2 or its complexes\", \"Shedding protease identity unknown\", \"Relative in vivo contributions of dual mechanisms not quantified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 3, 10]},\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 1, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [1, 2, 12]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [0, 2, 3, 7, 10]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"GRIA4\",\n      \"GRIA1\",\n      \"C1Q\",\n      \"TARDBP\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}