{"gene":"CHRM5","run_date":"2026-04-28T17:28:52","timeline":{"discoveries":[{"year":2021,"finding":"M5 muscarinic receptor (Chrm5) in the ventral subiculum (vSub) modulates initial motivation for alcohol self-administration in male alcohol-preferring rats; intra-vSub administration of a negative allosteric modulator of M5 (ML375) reduced alcohol self-administration but not context-induced alcohol-seeking. Chrm5 mRNA was up-regulated in the vSub following long-term alcohol consumption, and Chrm5 was localized on vSub neurons projecting to the nucleus accumbens shell via retrograde tracing combined with RNAscope.","method":"RT-qPCR, retrograde tracing + RNAscope in situ hybridization, intra-vSub pharmacology with selective allosteric modulators, operant alcohol self-administration and context-induced reinstatement assays","journal":"British journal of pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 — clean in vivo loss-of-function (allosteric inhibition) with defined behavioral phenotype and localization by two orthogonal methods; single lab","pmids":["33942300"],"is_preprint":false},{"year":2025,"finding":"In aged bone marrow, non-neurogenic acetylcholine signals through Chrm5 to activate eNOS-nitric oxide signaling in arterial endothelium, promoting arterial dilation and maintaining bone marrow blood flow and sinusoidal wall shear stress, which in turn supports transendothelial migration and homing of hematopoietic stem and progenitor cells (HSPCs). With aging, degradation of this non-neurogenic acetylcholine disrupts Chrm5-eNOS-NO signaling, reducing arterial dilation and impairing HSPC homing.","method":"In vivo imaging, pharmacological manipulation, integrative metabolomic analyses, and functional homing assays in mice","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo functional assay with pharmacological intervention, metabolomics, and imaging; single lab but multiple orthogonal methods","pmids":["40593589"],"is_preprint":false},{"year":2023,"finding":"A homozygous missense variant (p.Gln184Arg) in CHRM5 was identified in a patient with neurogenic bladder and secondary CAKUT complications. CHRM5 is expressed in murine and human bladder walls and Chrm5 knockout mice exhibit bladder overactivity, consistent with a role for CHRM5 in bladder contraction regulation. However, functional in vitro studies of the variant did not provide further mechanistic support.","method":"Exome sequencing, expression analysis (murine and human bladder), review of Chrm5 knockout mouse phenotype data","journal":"American journal of medical genetics. Part A","confidence":"Low","confidence_rationale":"Tier 3 — expression data plus KO phenotype referenced from prior work; functional in vitro studies were inconclusive","pmids":["37213061"],"is_preprint":false},{"year":1999,"finding":"Mouse Chrm4 and Chrm5 genes were both mapped to chromosome 2 by restriction fragment length variant analysis in interspecific backcross mice; sequencing of Chrm5 in El2 epilepsy mutant mice did not support Chrm5 as the El2 causative gene.","method":"RFLV mapping in interspecific backcross mice; Chrm5 gene sequencing in El2 mutant mice","journal":"Genes & genetic systems","confidence":"Medium","confidence_rationale":"Tier 2 — direct genetic mapping with sequencing confirmation; replicated across all five Chrm loci","pmids":["10549128"],"is_preprint":false},{"year":2012,"finding":"Deletion of Chrm5 (along with Chrm1, Chrm3, and Chrm4) in mice did not alter basal ciliary beat frequency or particle transport speed in the oviductal ampulla, demonstrating that the high autonomous ciliary activity in this tissue is independent of the intrinsic muscarinic cholinergic system. RT-PCR of laser-microdissected oviductal epithelium showed that only Chrm1 and Chrm3 subtypes are expressed there, not Chrm5.","method":"RT-PCR of laser-assisted microdissected epithelium; measurement of ciliary beat frequency and particle transport speed in Chrm1/3/4/5 knockout mice","journal":"Biology of reproduction","confidence":"Medium","confidence_rationale":"Tier 2 — clean KO with defined functional readout (CBF and PTS); multiple receptor knockouts compared","pmids":["22302687"],"is_preprint":false}],"current_model":"CHRM5 encodes a Gq/11-coupled muscarinic acetylcholine receptor expressed in dopaminergic neurons of the ventral tegmental area, ventral subiculum, bladder wall, and bone marrow vasculature, where it regulates mesolimbic dopamine-dependent reward behaviors (including alcohol motivation), bladder contractile activity, and arterial eNOS-nitric oxide signaling that supports hematopoietic stem cell homing; loss of Chrm5 or its disruption by age-related acetylcholine depletion impairs each of these downstream effector pathways."},"narrative":{"teleology":[{"year":1999,"claim":"Establishing the chromosomal location of Chrm5 was a prerequisite for candidate-gene studies; mapping to mouse chromosome 2 and sequencing in the El2 epilepsy model excluded Chrm5 as the El2 causative locus.","evidence":"Restriction fragment length variant analysis in interspecific backcross mice and Chrm5 sequencing in El2 mutants","pmids":["10549128"],"confidence":"Medium","gaps":["No functional consequence of Chrm5 loss was tested in this study","Human chromosomal synteny not explicitly confirmed here"]},{"year":2012,"claim":"Testing whether Chrm5 contributes to oviductal ciliary function revealed that it is not expressed in oviductal epithelium and its deletion does not affect ciliary beat frequency, defining a tissue where Chrm5 is dispensable.","evidence":"RT-PCR of laser-microdissected oviductal epithelium and ciliary beat frequency measurement in Chrm1/3/4/5 knockout mice","pmids":["22302687"],"confidence":"Medium","gaps":["Other potential Chrm5-expressing tissues were not surveyed in parallel","Whether Chrm5 plays a role in other mucosal ciliated epithelia was not tested"]},{"year":2021,"claim":"Demonstrating that Chrm5 in the ventral subiculum modulates alcohol self-administration via projections to the nucleus accumbens shell provided the first circuit-level mechanism linking M5 receptors to reward-driven behavior.","evidence":"Intra-vSub infusion of the M5 negative allosteric modulator ML375 combined with retrograde tracing and RNAscope in alcohol-preferring rats","pmids":["33942300"],"confidence":"Medium","gaps":["Genetic loss-of-function (knockout or knockdown) in the vSub has not been performed","Downstream signaling cascade from M5 activation in vSub neurons is undefined","Generalizability beyond alcohol-preferring rat strain not established"]},{"year":2023,"claim":"Identification of a homozygous CHRM5 missense variant in a neurogenic bladder patient, combined with prior Chrm5-KO bladder overactivity data, implicated CHRM5 in human bladder contractile regulation, though functional validation of the variant itself was inconclusive.","evidence":"Exome sequencing of patient; expression analysis in murine and human bladder; reference to Chrm5 KO mouse phenotype","pmids":["37213061"],"confidence":"Low","gaps":["In vitro functional assays of the p.Gln184Arg variant did not demonstrate a clear mechanistic effect","Causality between CHRM5 and neurogenic bladder not established in additional families or rescue experiments","Signaling pathway downstream of CHRM5 in bladder smooth muscle is uncharacterized"]},{"year":2025,"claim":"Revealing that non-neurogenic acetylcholine signals through Chrm5 on arterial endothelium to activate eNOS–NO–dependent arterial dilation established a vascular mechanism by which M5 receptors support hematopoietic stem cell homing, and showed that age-related acetylcholine loss disrupts this axis.","evidence":"In vivo imaging, pharmacological manipulation, metabolomics, and functional HSPC homing assays in mice","pmids":["40593589"],"confidence":"Medium","gaps":["Endothelial-specific Chrm5 knockout has not been reported","Whether Chrm5 agonism can rescue age-related homing defects is untested","Relative contribution of Chrm5 versus other muscarinic receptors on bone marrow endothelium is unclear"]},{"year":null,"claim":"The intracellular signaling cascades downstream of CHRM5 in each expressing tissue (brain, bladder, vasculature) remain incompletely defined, and no structural model of CHRM5-specific ligand recognition or allosteric modulation has been reported.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No cryo-EM or crystal structure of CHRM5 is available","Tissue-specific Chrm5 conditional knockouts have not been generated","Endogenous signaling complexes (scaffolds, effectors) interacting with CHRM5 are uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,1]}],"pathway":[],"complexes":[],"partners":["NOS3"],"other_free_text":[]},"mechanistic_narrative":"CHRM5 encodes the M5 muscarinic acetylcholine receptor, a Gq/11-coupled GPCR that transduces acetylcholine signaling in distinct physiological contexts including mesolimbic reward circuitry, bladder smooth muscle, and bone marrow vasculature. In the ventral subiculum, CHRM5 is expressed on neurons projecting to the nucleus accumbens shell, where it modulates initial motivation for alcohol self-administration, and its mRNA is upregulated by chronic alcohol exposure [PMID:33942300]. In bone marrow arterial endothelium, CHRM5 activates eNOS–nitric oxide signaling to maintain arterial dilation and sinusoidal shear stress required for hematopoietic stem cell transendothelial migration and homing, a pathway that deteriorates with age-related acetylcholine depletion [PMID:40593589]."},"prefetch_data":{"uniprot":{"accession":"P08912","full_name":"Muscarinic acetylcholine receptor M5","aliases":[],"length_aa":532,"mass_kda":60.1,"function":"The muscarinic acetylcholine receptor mediates various cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides and modulation of potassium channels through the action of G proteins. Primary transducing effect is Pi turnover","subcellular_location":"Cell membrane; Postsynaptic cell membrane","url":"https://www.uniprot.org/uniprotkb/P08912/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CHRM5","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/CHRM5","total_profiled":1310},"omim":[{"mim_id":"118496","title":"CHOLINERGIC RECEPTOR, MUSCARINIC, 5; CHRM5","url":"https://www.omim.org/entry/118496"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":7.1}],"url":"https://www.proteinatlas.org/search/CHRM5"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P08912","domains":[{"cath_id":"1.20.1070.10","chopping":"26-234_447-522","consensus_level":"medium","plddt":92.8209,"start":26,"end":522}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P08912","model_url":"https://alphafold.ebi.ac.uk/files/AF-P08912-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P08912-F1-predicted_aligned_error_v6.png","plddt_mean":68.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CHRM5","jax_strain_url":"https://www.jax.org/strain/search?query=CHRM5"},"sequence":{"accession":"P08912","fasta_url":"https://rest.uniprot.org/uniprotkb/P08912.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P08912/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P08912"}},"corpus_meta":[{"pmid":"15292665","id":"PMC_15292665","title":"Linkage of M5 muscarinic and alpha7-nicotinic receptor genes on 15q13 to schizophrenia.","date":"2004","source":"Neuropsychobiology","url":"https://pubmed.ncbi.nlm.nih.gov/15292665","citation_count":57,"is_preprint":false},{"pmid":"17163532","id":"PMC_17163532","title":"Characterization of a 5.3 Mb deletion in 15q14 by comparative genomic hybridization using a whole genome \"tiling path\" BAC array in a girl with heart defect, cleft palate, and developmental delay.","date":"2007","source":"American journal of medical genetics. 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Chrm5 mRNA was up-regulated in the vSub following long-term alcohol consumption, and Chrm5 was localized on vSub neurons projecting to the nucleus accumbens shell via retrograde tracing combined with RNAscope.\",\n      \"method\": \"RT-qPCR, retrograde tracing + RNAscope in situ hybridization, intra-vSub pharmacology with selective allosteric modulators, operant alcohol self-administration and context-induced reinstatement assays\",\n      \"journal\": \"British journal of pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean in vivo loss-of-function (allosteric inhibition) with defined behavioral phenotype and localization by two orthogonal methods; single lab\",\n      \"pmids\": [\"33942300\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In aged bone marrow, non-neurogenic acetylcholine signals through Chrm5 to activate eNOS-nitric oxide signaling in arterial endothelium, promoting arterial dilation and maintaining bone marrow blood flow and sinusoidal wall shear stress, which in turn supports transendothelial migration and homing of hematopoietic stem and progenitor cells (HSPCs). With aging, degradation of this non-neurogenic acetylcholine disrupts Chrm5-eNOS-NO signaling, reducing arterial dilation and impairing HSPC homing.\",\n      \"method\": \"In vivo imaging, pharmacological manipulation, integrative metabolomic analyses, and functional homing assays in mice\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo functional assay with pharmacological intervention, metabolomics, and imaging; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"40593589\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"A homozygous missense variant (p.Gln184Arg) in CHRM5 was identified in a patient with neurogenic bladder and secondary CAKUT complications. CHRM5 is expressed in murine and human bladder walls and Chrm5 knockout mice exhibit bladder overactivity, consistent with a role for CHRM5 in bladder contraction regulation. However, functional in vitro studies of the variant did not provide further mechanistic support.\",\n      \"method\": \"Exome sequencing, expression analysis (murine and human bladder), review of Chrm5 knockout mouse phenotype data\",\n      \"journal\": \"American journal of medical genetics. Part A\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — expression data plus KO phenotype referenced from prior work; functional in vitro studies were inconclusive\",\n      \"pmids\": [\"37213061\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Mouse Chrm4 and Chrm5 genes were both mapped to chromosome 2 by restriction fragment length variant analysis in interspecific backcross mice; sequencing of Chrm5 in El2 epilepsy mutant mice did not support Chrm5 as the El2 causative gene.\",\n      \"method\": \"RFLV mapping in interspecific backcross mice; Chrm5 gene sequencing in El2 mutant mice\",\n      \"journal\": \"Genes & genetic systems\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct genetic mapping with sequencing confirmation; replicated across all five Chrm loci\",\n      \"pmids\": [\"10549128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Deletion of Chrm5 (along with Chrm1, Chrm3, and Chrm4) in mice did not alter basal ciliary beat frequency or particle transport speed in the oviductal ampulla, demonstrating that the high autonomous ciliary activity in this tissue is independent of the intrinsic muscarinic cholinergic system. RT-PCR of laser-microdissected oviductal epithelium showed that only Chrm1 and Chrm3 subtypes are expressed there, not Chrm5.\",\n      \"method\": \"RT-PCR of laser-assisted microdissected epithelium; measurement of ciliary beat frequency and particle transport speed in Chrm1/3/4/5 knockout mice\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined functional readout (CBF and PTS); multiple receptor knockouts compared\",\n      \"pmids\": [\"22302687\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CHRM5 encodes a Gq/11-coupled muscarinic acetylcholine receptor expressed in dopaminergic neurons of the ventral tegmental area, ventral subiculum, bladder wall, and bone marrow vasculature, where it regulates mesolimbic dopamine-dependent reward behaviors (including alcohol motivation), bladder contractile activity, and arterial eNOS-nitric oxide signaling that supports hematopoietic stem cell homing; loss of Chrm5 or its disruption by age-related acetylcholine depletion impairs each of these downstream effector pathways.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CHRM5 encodes the M5 muscarinic acetylcholine receptor, a Gq/11-coupled GPCR that transduces acetylcholine signaling in distinct physiological contexts including mesolimbic reward circuitry, bladder smooth muscle, and bone marrow vasculature. In the ventral subiculum, CHRM5 is expressed on neurons projecting to the nucleus accumbens shell, where it modulates initial motivation for alcohol self-administration, and its mRNA is upregulated by chronic alcohol exposure [PMID:33942300]. In bone marrow arterial endothelium, CHRM5 activates eNOS–nitric oxide signaling to maintain arterial dilation and sinusoidal shear stress required for hematopoietic stem cell transendothelial migration and homing, a pathway that deteriorates with age-related acetylcholine depletion [PMID:40593589].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Establishing the chromosomal location of Chrm5 was a prerequisite for candidate-gene studies; mapping to mouse chromosome 2 and sequencing in the El2 epilepsy model excluded Chrm5 as the El2 causative locus.\",\n      \"evidence\": \"Restriction fragment length variant analysis in interspecific backcross mice and Chrm5 sequencing in El2 mutants\",\n      \"pmids\": [\"10549128\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No functional consequence of Chrm5 loss was tested in this study\",\n        \"Human chromosomal synteny not explicitly confirmed here\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Testing whether Chrm5 contributes to oviductal ciliary function revealed that it is not expressed in oviductal epithelium and its deletion does not affect ciliary beat frequency, defining a tissue where Chrm5 is dispensable.\",\n      \"evidence\": \"RT-PCR of laser-microdissected oviductal epithelium and ciliary beat frequency measurement in Chrm1/3/4/5 knockout mice\",\n      \"pmids\": [\"22302687\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Other potential Chrm5-expressing tissues were not surveyed in parallel\",\n        \"Whether Chrm5 plays a role in other mucosal ciliated epithelia was not tested\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstrating that Chrm5 in the ventral subiculum modulates alcohol self-administration via projections to the nucleus accumbens shell provided the first circuit-level mechanism linking M5 receptors to reward-driven behavior.\",\n      \"evidence\": \"Intra-vSub infusion of the M5 negative allosteric modulator ML375 combined with retrograde tracing and RNAscope in alcohol-preferring rats\",\n      \"pmids\": [\"33942300\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Genetic loss-of-function (knockout or knockdown) in the vSub has not been performed\",\n        \"Downstream signaling cascade from M5 activation in vSub neurons is undefined\",\n        \"Generalizability beyond alcohol-preferring rat strain not established\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identification of a homozygous CHRM5 missense variant in a neurogenic bladder patient, combined with prior Chrm5-KO bladder overactivity data, implicated CHRM5 in human bladder contractile regulation, though functional validation of the variant itself was inconclusive.\",\n      \"evidence\": \"Exome sequencing of patient; expression analysis in murine and human bladder; reference to Chrm5 KO mouse phenotype\",\n      \"pmids\": [\"37213061\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"In vitro functional assays of the p.Gln184Arg variant did not demonstrate a clear mechanistic effect\",\n        \"Causality between CHRM5 and neurogenic bladder not established in additional families or rescue experiments\",\n        \"Signaling pathway downstream of CHRM5 in bladder smooth muscle is uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealing that non-neurogenic acetylcholine signals through Chrm5 on arterial endothelium to activate eNOS–NO–dependent arterial dilation established a vascular mechanism by which M5 receptors support hematopoietic stem cell homing, and showed that age-related acetylcholine loss disrupts this axis.\",\n      \"evidence\": \"In vivo imaging, pharmacological manipulation, metabolomics, and functional HSPC homing assays in mice\",\n      \"pmids\": [\"40593589\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Endothelial-specific Chrm5 knockout has not been reported\",\n        \"Whether Chrm5 agonism can rescue age-related homing defects is untested\",\n        \"Relative contribution of Chrm5 versus other muscarinic receptors on bone marrow endothelium is unclear\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The intracellular signaling cascades downstream of CHRM5 in each expressing tissue (brain, bladder, vasculature) remain incompletely defined, and no structural model of CHRM5-specific ligand recognition or allosteric modulation has been reported.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No cryo-EM or crystal structure of CHRM5 is available\",\n        \"Tissue-specific Chrm5 conditional knockouts have not been generated\",\n        \"Endogenous signaling complexes (scaffolds, effectors) interacting with CHRM5 are uncharacterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": []}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"NOS3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\nWait, I need to correct the pathway field — it should use Reactome IDs, not GO IDs. Let me reconsider.\n\n```json\n{\n  \"mechanistic_narrative\": \"CHRM5 encodes the M5 muscarinic acetylcholine receptor, a Gq/11-coupled GPCR that transduces acetylcholine signaling in distinct physiological contexts including mesolimbic reward circuitry, bladder smooth muscle, and bone marrow vasculature. In the ventral subiculum, CHRM5 is expressed on neurons projecting to the nucleus accumbens shell, where it modulates initial motivation for alcohol self-administration, and its mRNA is upregulated by chronic alcohol exposure [PMID:33942300]. In bone marrow arterial endothelium, CHRM5 activates eNOS–nitric oxide signaling to maintain arterial dilation and sinusoidal shear stress required for hematopoietic stem cell transendothelial migration and homing, a pathway that deteriorates with age-related acetylcholine depletion [PMID:40593589].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Establishing the chromosomal location of Chrm5 was a prerequisite for candidate-gene studies; mapping to mouse chromosome 2 and sequencing in the El2 epilepsy model excluded Chrm5 as the El2 causative locus.\",\n      \"evidence\": \"Restriction fragment length variant analysis in interspecific backcross mice and Chrm5 sequencing in El2 mutants\",\n      \"pmids\": [\"10549128\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No functional consequence of Chrm5 loss was tested in this study\",\n        \"Human chromosomal synteny not explicitly confirmed here\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Testing whether Chrm5 contributes to oviductal ciliary function revealed that it is not expressed in oviductal epithelium and its deletion does not affect ciliary beat frequency, defining a tissue where Chrm5 is dispensable.\",\n      \"evidence\": \"RT-PCR of laser-microdissected oviductal epithelium and ciliary beat frequency measurement in Chrm1/3/4/5 knockout mice\",\n      \"pmids\": [\"22302687\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Other potential Chrm5-expressing tissues were not surveyed in parallel\",\n        \"Whether Chrm5 plays a role in other mucosal ciliated epithelia was not tested\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstrating that Chrm5 in the ventral subiculum modulates alcohol self-administration via projections to the nucleus accumbens shell provided the first circuit-level mechanism linking M5 receptors to reward-driven behavior.\",\n      \"evidence\": \"Intra-vSub infusion of the M5 negative allosteric modulator ML375 combined with retrograde tracing and RNAscope in alcohol-preferring rats\",\n      \"pmids\": [\"33942300\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Genetic loss-of-function (knockout or knockdown) in the vSub has not been performed\",\n        \"Downstream signaling cascade from M5 activation in vSub neurons is undefined\",\n        \"Generalizability beyond alcohol-preferring rat strain not established\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identification of a homozygous CHRM5 missense variant in a neurogenic bladder patient, combined with prior Chrm5-KO bladder overactivity data, implicated CHRM5 in human bladder contractile regulation, though functional validation of the variant itself was inconclusive.\",\n      \"evidence\": \"Exome sequencing of patient; expression analysis in murine and human bladder; reference to Chrm5 KO mouse phenotype\",\n      \"pmids\": [\"37213061\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"In vitro functional assays of the p.Gln184Arg variant did not demonstrate a clear mechanistic effect\",\n        \"Causality between CHRM5 and neurogenic bladder not established in additional families or rescue experiments\",\n        \"Signaling pathway downstream of CHRM5 in bladder smooth muscle is uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealing that non-neurogenic acetylcholine signals through Chrm5 on arterial endothelium to activate eNOS–NO–dependent arterial dilation established a vascular mechanism by which M5 receptors support hematopoietic stem cell homing, and showed that age-related acetylcholine loss disrupts this axis.\",\n      \"evidence\": \"In vivo imaging, pharmacological manipulation, metabolomics, and functional HSPC homing assays in mice\",\n      \"pmids\": [\"40593589\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Endothelial-specific Chrm5 knockout has not been reported\",\n        \"Whether Chrm5 agonism can rescue age-related homing defects is untested\",\n        \"Relative contribution of Chrm5 versus other muscarinic receptors on bone marrow endothelium is unclear\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The intracellular signaling cascades downstream of CHRM5 in each expressing tissue (brain, bladder, vasculature) remain incompletely defined, and no structural model of CHRM5-specific ligand recognition or allosteric modulation has been reported.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No cryo-EM or crystal structure of CHRM5 is available\",\n        \"Tissue-specific Chrm5 conditional knockouts have not been generated\",\n        \"Endogenous signaling complexes (scaffolds, effectors) interacting with CHRM5 are uncharacterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"NOS3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}