{"gene":"BLVRA","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":1983,"finding":"BLVRA encodes a monomeric enzyme (~34 kDa) that uses both NADH and NADPH as cofactors, with both activities arising from a single gene product. Demonstrated by gel electrophoresis with chromogenic staining and somatic cell hybrid mapping.","method":"Gel electrophoresis with specific chromogenic staining; somatic cell hybrid complementation","journal":"Biochemical genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct enzymatic assay demonstrating cofactor usage and monomeric structure, single lab but with orthogonal methods (electrophoresis + somatic cell hybrids)","pmids":["6838484"],"is_preprint":false},{"year":1997,"finding":"BVR-A catalyzes reduction of biliverdin IXα to bilirubin as a monomer (~34 kDa) using NADH; the reaction proceeds with B-face stereospecific oxidation of NADH, demonstrated by pre-steady-state burst kinetics with pH dependence.","method":"Recombinant GST-BVR-A fusion protein expression, gel filtration, in vitro enzymatic assay, stereospecificity assay with [4-³H]NADH","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstituted in vitro enzymatic activity with stereospecificity established by isotope labeling and pre-steady-state kinetics, single lab but multiple orthogonal in vitro methods","pmids":["9359830"],"is_preprint":false},{"year":2011,"finding":"A homozygous nonsense mutation (c.214C>A, p.Ser44X) in BLVRA generates a truncated protein with no catalytic activity, leading to accumulation of biliverdin (hyperbiliverdinaemia) during cholestasis episodes. Complete absence of BVR-A activity is non-lethal.","method":"Site-directed mutagenesis, expression in human hepatoma liver cells and Xenopus laevis oocytes, immunoblotting, immunofluorescence, functional BVR-A activity assay","journal":"Journal of medical genetics","confidence":"High","confidence_rationale":"Tier 1 / Moderate — loss-of-function mutagenesis combined with enzymatic activity assay and heterologous expression in two cell systems, confirmed in human patients","pmids":["21278388"],"is_preprint":false},{"year":2015,"finding":"BVRA mediates macrophage expression of the anti-inflammatory cytokine IL-10. BVRA overexpression increased IL-10 mRNA and protein levels, while BVRA knockdown decreased IL-10, without affecting TNF-α, indicating a specific IL-10 regulatory role in macrophages.","method":"Recombinant adenovirus-mediated BVRA overexpression and siRNA knockdown in bone marrow-derived macrophages; ELISA and mRNA quantification; in vivo renal ischemia-reperfusion injury model","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal gain- and loss-of-function in primary macrophages with in vivo validation, single lab","pmids":["26393580"],"is_preprint":false},{"year":2018,"finding":"BLVRA is a direct target of miR-222 at its 3'-UTR; miR-222 suppression increases BLVRA protein levels, and BLVRA overexpression promotes erythroid differentiation of K562 cells and CD34+ HPCs, while BLVRA silencing attenuates hemin-induced erythroid differentiation.","method":"Luciferase 3'-UTR reporter assay, miR-222 mimic/inhibitor transfection, siRNA knockdown, quantitative proteomics, erythroid differentiation assay","journal":"Cell biochemistry and function","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct 3'-UTR luciferase validation plus reciprocal gain/loss-of-function for differentiation phenotype, single lab","pmids":["29368338"],"is_preprint":false},{"year":2019,"finding":"BVRA-mediated biliverdin reduction to bilirubin inhibits TLR4 signaling in human leukocytes. Biliverdin triggers phosphorylation of mTORC2-specific targets (Akt, PKCζ, AMPKα-LKB1-TSC1/2) and their physical association with BVRA. TLR4 activation counter-suppresses BVRA expression, indicating a reciprocal regulatory axis.","method":"Phosphoprotein analysis (Western blot), co-immunoprecipitation of BVRA with mTORC2 targets, pharmacological inhibition (Torin, PP242, PKCζ inhibitory peptide), in vivo human samples (cardiopulmonary bypass patients, T2D patients)","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP and pharmacological dissection of pathway, human in vivo data supporting the model, single lab","pmids":["31065010"],"is_preprint":false},{"year":2019,"finding":"Loss of BVRA in hepatocytes (CRISPR-Cas9 knockout) causes reduced bilirubin production, increased ROS, lipid accumulation, decreased mitochondrial number, reduced mitochondrial biogenesis markers, and impaired oxidative phosphorylation, establishing BVRA as a protector against lipid accumulation and oxidative stress in hepatocytes.","method":"CRISPR-Cas9 gene knockout in murine hepa1c1c7 hepatocytes, enzymatic activity assay, lipid staining, ROS measurement, mitochondrial oxygen consumption assay, gene expression analysis","journal":"Archives of biochemistry and biophysics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with multiple orthogonal phenotypic readouts (ROS, lipid, mitochondria, respiration), single lab","pmids":["31422074"],"is_preprint":false},{"year":2020,"finding":"Adipose-specific deletion of BVRA in mice leads to increased visceral fat, reduced mitochondrial number in white adipose tissue (WAT), increased adipocyte hypertrophy and inflammation, decreased expression of browning genes (Ppara, Adrb3), and impaired insulin signaling in WAT (reduced pAKT and Glut4 mRNA), establishing BVRA as a regulator of WAT mitochondrial function and insulin signaling.","method":"Adipose-specific conditional Blvra knockout mouse (BlvraFatKO), body composition analysis, histology, gene expression profiling, Western blot for pAKT","journal":"Biomolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — tissue-specific KO mouse with multiple orthogonal mechanistic readouts, single lab","pmids":["32131495"],"is_preprint":false},{"year":2020,"finding":"BVR-A deficiency in mouse brain cortex leads to mTOR hyperactivation and impairment of autophagy (reduced Beclin-1, LC3, LC3II/I ratio, Atg5-Atg12, Atg7), with dysregulated AMPK identified as the critical upstream driver of mTOR hyperactivation in the absence of BVR-A.","method":"BVR-A knockout mouse (BVR-A-/-), age-series cortex analysis (2, 6, 11 months), Western blot for mTOR/AMPK/autophagy pathway components, oxidative stress markers","journal":"Antioxidants (Basel, Switzerland)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO model with longitudinal mechanistic pathway analysis via Western blot, single lab","pmids":["32727065"],"is_preprint":false},{"year":2020,"finding":"BLVRA overexpression in colorectal cancer cells activates Wnt/β-catenin signaling (upregulates c-MYC, β-catenin, Cyclin D1) to promote proliferation, migration, invasion, and EMT; BLVRA knockdown produces opposite effects and blocks pathway activation.","method":"Lentiviral overexpression and knockdown in HT-29 and SW620 CRC cells, Western blot for Wnt/β-catenin pathway targets, MTT proliferation assay, flow cytometry apoptosis, Transwell migration/invasion assay","journal":"Cancer management and research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — gain/loss-of-function with pathway target assessment by Western blot but no direct mechanistic link established between BLVRA enzymatic activity and Wnt pathway, single lab, single study","pmids":["32425592"],"is_preprint":false},{"year":2020,"finding":"Elevated BVRA in high-capacity running (HCR) rats correlates with higher plasma bilirubin and reduced UGT1A1, and increased PPARα target genes (Fgf21, Abcd3, Gys2), indicating that exercise-induced increases in bilirubin production involve upregulation of hepatic BVRA and suppression of UGT1A1.","method":"Genetically selected rat strains (HCR vs LCR), plasma bilirubin measurement, hepatic enzyme protein/activity quantification, gene expression analysis, PAS staining for glycogen","journal":"Antioxidants (Basel, Switzerland)","confidence":"Low","confidence_rationale":"Tier 3 / Weak — correlative measurement in animal model without direct mechanistic intervention on BVRA itself, single lab","pmids":["32961782"],"is_preprint":false},{"year":2022,"finding":"KRGE-induced BVR-A expression and subsequent bilirubin production in astrocytes regulates mitochondrial function (membrane potential, mass, oxidative phosphorylation) through LKB1, SIRT1, and ERRα, and modulates mitochondria-localized proteins (SIRT5, Tom20, Tom22, cytochrome c, SOD2). This BVR-A-LKB1-SIRT1-ERRα pathway was AMPKα-independent.","method":"KRGE treatment of hippocampal astrocytes in vivo (mice) and in vitro, BVR-A knockdown/overexpression, mitochondrial membrane potential assay, Western blot for pathway components, immunofluorescence","journal":"Antioxidants (Basel, Switzerland)","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pathway placement via KD/OE with multiple readouts but mechanism is indirect (bilirubin-mediated), single lab, single study","pmids":["36139815"],"is_preprint":false},{"year":2023,"finding":"GK2-BLVRA fusion protein (using a novel protein transduction domain) transduces into dopaminergic neurons, suppresses MAPK activation, modulates apoptosis-related proteins (Bcl-2, Bax, caspase-3/-9), reduces ROS and DNA damage after MPP+ exposure, and reduces dopaminergic neuronal death in MPTP-treated mice, demonstrating that BLVRA antioxidant activity protects dopaminergic neurons.","method":"Recombinant fusion protein transduction into SH-SY5Y cells and in vivo MPTP mouse model; Western blot for MAPK and apoptosis proteins; ROS measurement; immunohistochemistry for dopaminergic neurons","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein delivery with mechanistic readouts in both in vitro and in vivo PD models, single lab","pmids":["36688733"],"is_preprint":false},{"year":2024,"finding":"BLVRA knockdown in HCC cells (HepG2, Hep3B) suppresses proliferation, cell cycle progression, invasion, migration, and induces apoptosis, with reduction of Wnt/β-catenin targets (c-MYC, β-catenin, Cyclin D1); WNT inhibitor IWP-4 phenocopies BLVRA knockdown, placing BLVRA upstream of Wnt/β-catenin in HCC.","method":"siRNA knockdown in HCC cell lines, Western blot for Wnt/β-catenin pathway, cell proliferation and apoptosis assays, pharmacological Wnt inhibition (IWP-4), invasion/migration assays","journal":"Journal of molecular histology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — KD with pharmacological epistasis supporting Wnt pathway placement, but no direct biochemical link between BLVRA and pathway components established, single lab","pmids":["38216836"],"is_preprint":false},{"year":2024,"finding":"Homozygous large deletions in canine BLVRA causing predicted truncations result in loss of BVR-A enzymatic function and biliverdinuria, confirming that BLVRA loss-of-function causes biliverdin accumulation in a non-human mammal.","method":"Whole genome sequencing, Sanger sequencing, urinary mass spectrometry for biliverdin quantification in dogs","journal":"Genes","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genomic deletion confirmed by two sequencing methods with direct metabolite measurement, ortholog of human BLVRA, replicates human inactivating mutation finding","pmids":["39766828"],"is_preprint":false},{"year":2025,"finding":"BVRA directly interacts with Nrf2 (the master redox transcription factor) in a non-enzymatic capacity, modulating the expression of neuroprotective Nrf2 target genes including those dysregulated in Alzheimer's disease, as revealed by ChIP-seq and RNA-seq.","method":"Co-immunoprecipitation/direct interaction assay, ChIP-seq, RNA-seq in brain cells; BVRA knockout model comparison","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein-protein interaction plus genome-wide transcriptional analysis (ChIP-seq/RNA-seq), preprint not yet peer-reviewed, single lab","pmids":["bio_10.1101_2025.06.04.657936"],"is_preprint":true}],"current_model":"BLVRA encodes biliverdin reductase A, a monomeric cytosolic enzyme that catalyzes B-face stereospecific reduction of biliverdin IXα to bilirubin using NADH or NADPH; beyond this enzymatic role it functions as a signaling scaffold that physically associates with mTORC2 targets (Akt, PKCζ, AMPK) to suppress TLR4-driven inflammation, regulates the AMPK/mTOR/autophagy axis in the brain, promotes IL-10 production in macrophages, supports mitochondrial biogenesis and insulin signaling in adipocytes and hepatocytes, promotes erythroid differentiation, and non-enzymatically interacts with Nrf2 to coordinate neuroprotective gene expression."},"narrative":{"mechanistic_narrative":"BLVRA encodes biliverdin reductase A, a monomeric ~34 kDa cytosolic enzyme that catalyzes the B-face stereospecific reduction of biliverdin IXα to bilirubin using either NADH or NADPH, with both cofactor activities arising from a single gene product [PMID:6838484, PMID:9359830]. Complete loss of catalytic activity through nonsense or large deletion mutations causes biliverdin accumulation (hyperbiliverdinaemia/biliverdinuria) and is non-lethal in both humans and dogs [PMID:21278388, PMID:39766828]. Beyond bilirubin synthesis, BVRA serves as a signaling node that physically associates with mTORC2-pathway components (Akt, PKCζ, the AMPKα–LKB1–TSC1/2 module) to restrain TLR4-driven inflammation in leukocytes, a reciprocally regulated axis in which TLR4 activation suppresses BVRA [PMID:31065010], and it specifically promotes anti-inflammatory IL-10 expression in macrophages [PMID:26393580]. Through its bilirubin-generating and signaling functions BVRA protects cells from oxidative stress and supports mitochondrial biogenesis and oxidative phosphorylation in hepatocytes and adipocytes, where its loss produces lipid accumulation, mitochondrial deficits, and impaired insulin signaling [PMID:31422074, PMID:32131495]. In brain, BVRA constrains mTOR activity and sustains autophagy via AMPK, and protects neurons against oxidative damage [PMID:32727065, PMID:36688733]. BVRA also acts on cell-fate programs, being required for hemin-induced erythroid differentiation downstream of miR-222 regulation [PMID:29368338].","teleology":[{"year":1983,"claim":"Established that a single BLVRA gene product is a monomeric enzyme able to use both NADH and NADPH, resolving whether the dual-cofactor activity reflected one or two enzymes.","evidence":"Gel electrophoresis with chromogenic staining and somatic cell hybrid mapping","pmids":["6838484"],"confidence":"Medium","gaps":["Catalytic mechanism and stereochemistry not addressed","No recombinant reconstitution"]},{"year":1997,"claim":"Defined the enzymatic mechanism, showing BVR-A reduces biliverdin IXα to bilirubin with B-face stereospecific oxidation of NADH, establishing the chemistry of the core reaction.","evidence":"Recombinant GST-BVR-A, gel filtration, in vitro assay, [4-³H]NADH stereospecificity, pre-steady-state burst kinetics","pmids":["9359830"],"confidence":"High","gaps":["Structural basis of stereospecificity not resolved","Physiological consequences of bilirubin production not addressed"]},{"year":2011,"claim":"Demonstrated that complete loss of BVR-A activity in humans causes biliverdin accumulation but is non-lethal, defining the in vivo consequence of enzyme failure.","evidence":"Site-directed mutagenesis of c.214C>A (p.Ser44X), heterologous expression in hepatoma cells and Xenopus oocytes, activity assay, human patients","pmids":["21278388"],"confidence":"High","gaps":["Why loss is tolerated despite proposed signaling roles is unexplained","Non-enzymatic functions not tested in patients"]},{"year":2015,"claim":"Showed BVRA selectively drives macrophage IL-10 expression without affecting TNF-α, identifying a specific anti-inflammatory regulatory role.","evidence":"Adenoviral overexpression and siRNA knockdown in BMDMs, ELISA/mRNA, in vivo renal ischemia-reperfusion","pmids":["26393580"],"confidence":"Medium","gaps":["Molecular link between BVRA and IL-10 transcription not defined","Single lab"]},{"year":2018,"claim":"Placed BLVRA in a post-transcriptional regulatory circuit (miR-222 target) and showed it is required for erythroid differentiation, connecting the enzyme to cell-fate control.","evidence":"3'-UTR luciferase reporter, miR-222 mimic/inhibitor, siRNA, quantitative proteomics, erythroid differentiation of K562 and CD34+ cells","pmids":["29368338"],"confidence":"Medium","gaps":["Whether the differentiation effect requires enzymatic activity unknown","Downstream effectors not identified"]},{"year":2019,"claim":"Defined BVRA as a signaling scaffold that physically engages mTORC2 targets (Akt, PKCζ, AMPKα-LKB1-TSC1/2) to suppress TLR4 inflammation, revealing a non-canonical, reciprocally regulated function.","evidence":"Phosphoprotein Western blot, Co-IP of BVRA with mTORC2 targets, pharmacological inhibition (Torin, PP242, PKCζ peptide), human bypass and T2D samples","pmids":["31065010"],"confidence":"Medium","gaps":["Direct binding interfaces not mapped","Single lab without reciprocal structural validation"]},{"year":2019,"claim":"Established BVRA as a protector against hepatocyte lipid accumulation and oxidative stress through support of mitochondrial biogenesis and respiration.","evidence":"CRISPR-Cas9 knockout in hepa1c1c7 cells, activity assay, lipid/ROS staining, mitochondrial respiration, gene expression","pmids":["31422074"],"confidence":"Medium","gaps":["Enzymatic vs scaffold contribution to mitochondrial phenotype not separated","Single cell model"]},{"year":2020,"claim":"Extended BVRA's metabolic role to adipose tissue, showing adipose-specific deletion impairs WAT mitochondrial function and insulin signaling and promotes adiposity and inflammation.","evidence":"Adipose-specific Blvra knockout mice, body composition, histology, expression profiling, pAKT Western blot","pmids":["32131495"],"confidence":"Medium","gaps":["Upstream mechanism linking BVRA to browning genes not defined","Single lab"]},{"year":2020,"claim":"Showed BVR-A deficiency in brain cortex hyperactivates mTOR and impairs autophagy with dysregulated AMPK as the upstream driver, defining a neural AMPK/mTOR/autophagy role.","evidence":"BVR-A knockout mice, longitudinal cortex analysis, Western blot for mTOR/AMPK/autophagy markers","pmids":["32727065"],"confidence":"Medium","gaps":["How BVRA controls AMPK mechanistically unresolved","Behavioral/cognitive outcomes not linked"]},{"year":2020,"claim":"Linked BLVRA to Wnt/β-catenin signaling and proliferation in colorectal cancer cells via gain/loss-of-function.","evidence":"Lentiviral overexpression/knockdown in HT-29 and SW620, Western blot, proliferation/migration/invasion assays","pmids":["32425592"],"confidence":"Low","gaps":["No direct biochemical link between BLVRA and Wnt components established","Single study, single lab"]},{"year":2020,"claim":"Correlated exercise-associated hepatic BVRA upregulation with elevated bilirubin and PPARα target genes in a selected rat model.","evidence":"HCR vs LCR rat strains, plasma bilirubin, hepatic enzyme quantification, gene expression","pmids":["32961782"],"confidence":"Low","gaps":["Correlative only, no direct intervention on BVRA","Causality unestablished"]},{"year":2022,"claim":"Placed BVR-A in an AMPKα-independent LKB1-SIRT1-ERRα axis controlling astrocyte mitochondrial function via bilirubin production.","evidence":"KRGE treatment of astrocytes in vivo/in vitro, BVR-A KD/OE, mitochondrial membrane potential, Western blot, immunofluorescence","pmids":["36139815"],"confidence":"Low","gaps":["Mechanism is indirect via bilirubin","Single study, single lab"]},{"year":2023,"claim":"Demonstrated that delivered BLVRA antioxidant activity protects dopaminergic neurons by suppressing MAPK and apoptotic signaling in PD models.","evidence":"GK2-BLVRA fusion protein transduction into SH-SY5Y and MPTP mice, Western blot, ROS, immunohistochemistry","pmids":["36688733"],"confidence":"Medium","gaps":["Whether endogenous BVRA confers the same protection not tested","Distinction between enzymatic and scaffold contribution unclear"]},{"year":2024,"claim":"Confirmed in a second mammal (dog) that BLVRA loss-of-function causes biliverdin accumulation, generalizing the human enzymatic-deficiency phenotype.","evidence":"Whole genome and Sanger sequencing, urinary mass spectrometry for biliverdin in dogs","pmids":["39766828"],"confidence":"Medium","gaps":["Non-enzymatic functions not assessed in this ortholog","Systemic consequences not characterized"]},{"year":2024,"claim":"Reinforced BLVRA's upstream role in Wnt/β-catenin signaling in hepatocellular carcinoma using pharmacological epistasis.","evidence":"siRNA knockdown in HepG2/Hep3B, Western blot, proliferation/apoptosis assays, Wnt inhibitor IWP-4 epistasis","pmids":["38216836"],"confidence":"Low","gaps":["No direct biochemical interaction with Wnt components shown","Single lab"]},{"year":2025,"claim":"Proposed a non-enzymatic role for BVRA as a direct Nrf2 partner shaping neuroprotective transcriptional output, expanding its function into redox gene regulation.","evidence":"Co-IP/interaction assay, ChIP-seq, RNA-seq in brain cells with BVRA knockout comparison (preprint)","pmids":["bio_10.1101_2025.06.04.657936"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Direct binding interface and mechanism of transcriptional modulation not defined"]},{"year":null,"claim":"It remains unresolved how BVRA's enzymatic (bilirubin-producing) and non-enzymatic (scaffold/transcriptional) functions are mechanistically partitioned and which underlies each tissue-specific phenotype.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model distinguishing catalytic vs interaction surfaces","Causal separation of enzyme vs scaffold roles not achieved across tissues"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016491","term_label":"oxidoreductase activity","supporting_discovery_ids":[0,1,2,6,14]},{"term_id":"GO:0016209","term_label":"antioxidant activity","supporting_discovery_ids":[6,12]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[5,8]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,2]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,1,2,6,7]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[3,5]},{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[6,8,12]}],"complexes":[],"partners":["AKT1","PRKCZ","PRKAA1","STK11","NFE2L2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P53004","full_name":"Biliverdin reductase A","aliases":["Biliverdin-IX alpha-reductase"],"length_aa":296,"mass_kda":33.4,"function":"Reduces the gamma-methene bridge of the open tetrapyrrole, biliverdin IXalpha, to bilirubin with the concomitant oxidation of a NADH or NADPH cofactor (PubMed:10858451, PubMed:7929092, PubMed:8424666, PubMed:8631357). Does not reduce bilirubin IXbeta (PubMed:10858451). Uses the reactants NADH or NADPH depending on the pH; NADH is used at the acidic pH range (6-6.9) and NADPH at the alkaline range (8.5-8.7) (PubMed:7929092, PubMed:8424666, PubMed:8631357). NADPH, however, is the probable reactant in biological systems (PubMed:7929092)","subcellular_location":"Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/P53004/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BLVRA","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000106605","cell_line_id":"CID001132","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":3}],"interactors":[{"gene":"CARM1","stoichiometry":0.2},{"gene":"UVRAG","stoichiometry":0.2},{"gene":"DNAJB1","stoichiometry":0.2},{"gene":"CLCN7","stoichiometry":0.2},{"gene":"DNAJA2","stoichiometry":0.2},{"gene":"BRD4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001132","total_profiled":1310},"omim":[{"mim_id":"614156","title":"HYPERBILIVERDINEMIA; HBLVD","url":"https://www.omim.org/entry/614156"},{"mim_id":"601816","title":"BILIRUBIN, SERUM LEVEL OF, QUANTITATIVE TRAIT LOCUS 1; BILIQTL1","url":"https://www.omim.org/entry/601816"},{"mim_id":"600941","title":"BILIVERDIN REDUCTASE B; BLVRB","url":"https://www.omim.org/entry/600941"},{"mim_id":"109750","title":"BILIVERDIN REDUCTASE A; BLVRA","url":"https://www.omim.org/entry/109750"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/BLVRA"},"hgnc":{"alias_symbol":["BVRA","BVRalpha"],"prev_symbol":["BLVR"]},"alphafold":{"accession":"P53004","domains":[{"cath_id":"3.40.50.720","chopping":"8-124","consensus_level":"high","plddt":97.7189,"start":8,"end":124},{"cath_id":"3.30.360.10","chopping":"127-245_283-293","consensus_level":"high","plddt":96.3261,"start":127,"end":293}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P53004","model_url":"https://alphafold.ebi.ac.uk/files/AF-P53004-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P53004-F1-predicted_aligned_error_v6.png","plddt_mean":95.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BLVRA","jax_strain_url":"https://www.jax.org/strain/search?query=BLVRA"},"sequence":{"accession":"P53004","fasta_url":"https://rest.uniprot.org/uniprotkb/P53004.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P53004/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P53004"}},"corpus_meta":[{"pmid":"21278388","id":"PMC_21278388","title":"A homozygous nonsense mutation (c.214C->A) in the biliverdin reductase alpha gene (BLVRA) results in accumulation of biliverdin during episodes of cholestasis.","date":"2011","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21278388","citation_count":47,"is_preprint":false},{"pmid":"32131495","id":"PMC_32131495","title":"Biliverdin Reductase A (BVRA) Knockout in Adipocytes Induces Hypertrophy and Reduces Mitochondria in White Fat of Obese Mice.","date":"2020","source":"Biomolecules","url":"https://pubmed.ncbi.nlm.nih.gov/32131495","citation_count":46,"is_preprint":false},{"pmid":"31422074","id":"PMC_31422074","title":"CRISPR Cas9-mediated deletion of biliverdin reductase A (BVRA) in mouse liver cells induces oxidative stress and lipid accumulation.","date":"2019","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/31422074","citation_count":37,"is_preprint":false},{"pmid":"32961782","id":"PMC_32961782","title":"Rats Genetically Selected for High Aerobic Exercise Capacity Have Elevated Plasma Bilirubin by Upregulation of Hepatic Biliverdin Reductase-A (BVRA) and Suppression of UGT1A1.","date":"2020","source":"Antioxidants (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/32961782","citation_count":30,"is_preprint":false},{"pmid":"26393580","id":"PMC_26393580","title":"Biliverdin Reductase A (BVRA) Mediates Macrophage Expression of Interleukin-10 in Injured Kidney.","date":"2015","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/26393580","citation_count":20,"is_preprint":false},{"pmid":"32727065","id":"PMC_32727065","title":"BVR-A Deficiency Leads to Autophagy Impairment through the Dysregulation of AMPK/mTOR Axis in the Brain-Implications for Neurodegeneration.","date":"2020","source":"Antioxidants (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/32727065","citation_count":18,"is_preprint":false},{"pmid":"6838484","id":"PMC_6838484","title":"Electrophoretic characterization and genetics of human biliverdin reductase (BLVR; EC 1.3.1.24); assignment of BLVR to the p14 leads to cen region of human chromosome 7 in mouse-human somatic cell hybrids.","date":"1983","source":"Biochemical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/6838484","citation_count":16,"is_preprint":false},{"pmid":"31065010","id":"PMC_31065010","title":"TLR4 counteracts BVRA signaling in human leukocytes via differential regulation of AMPK, mTORC1 and mTORC2.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31065010","citation_count":14,"is_preprint":false},{"pmid":"2793182","id":"PMC_2793182","title":"Localization of Blvr, biliverdin reductase, on mouse chromosome 2.","date":"1989","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/2793182","citation_count":13,"is_preprint":false},{"pmid":"27740521","id":"PMC_27740521","title":"Predictive role BLVRA mRNA expression in hepatocellular cancer.","date":"2016","source":"Annals of hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/27740521","citation_count":12,"is_preprint":false},{"pmid":"9359830","id":"PMC_9359830","title":"Cloning and overexpression of rat kidney biliverdin IX alpha reductase as a fusion protein with glutathione S-transferase: stereochemistry of NADH oxidation and evidence that the presence of the glutathione S-transferase domain does not effect BVR-A activity.","date":"1997","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/9359830","citation_count":11,"is_preprint":false},{"pmid":"21721974","id":"PMC_21721974","title":"Association of a BLVRA common polymorphism with essential hypertension and blood pressure in Kazaks.","date":"2011","source":"Clinical and experimental hypertension (New York, N.Y. : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/21721974","citation_count":10,"is_preprint":false},{"pmid":"30636082","id":"PMC_30636082","title":"Associations between G6PD, OATP1B1 and BLVRA variants and susceptibility to neonatal hyperbilirubinaemia in a Chinese Han population.","date":"2019","source":"Journal of paediatrics and child health","url":"https://pubmed.ncbi.nlm.nih.gov/30636082","citation_count":9,"is_preprint":false},{"pmid":"32425592","id":"PMC_32425592","title":"Biliverdin Reductase A (BLVRA) Promotes Colorectal Cancer Cell Progression by Activating the Wnt/β-Catenin Signaling Pathway.","date":"2020","source":"Cancer management and research","url":"https://pubmed.ncbi.nlm.nih.gov/32425592","citation_count":8,"is_preprint":false},{"pmid":"29368338","id":"PMC_29368338","title":"Quantitative proteomics reveals that miR-222 inhibits erythroid differentiation by targeting BLVRA and CRKL.","date":"2018","source":"Cell biochemistry and function","url":"https://pubmed.ncbi.nlm.nih.gov/29368338","citation_count":8,"is_preprint":false},{"pmid":"36139815","id":"PMC_36139815","title":"Induction of BVR-A Expression by Korean Red Ginseng in Murine Hippocampal Astrocytes: Role of Bilirubin in Mitochondrial Function via the LKB1-SIRT1-ERRα Axis.","date":"2022","source":"Antioxidants (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/36139815","citation_count":7,"is_preprint":false},{"pmid":"37108445","id":"PMC_37108445","title":"Dynamic Changes of BVRA Protein Levels Occur in Response to Insulin: A Pilot Study in Humans.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37108445","citation_count":5,"is_preprint":false},{"pmid":"38279097","id":"PMC_38279097","title":"Associations between UGT1A1, SLCO1B1, SLCO1B3, BLVRA and HMOX1 polymorphisms and susceptibility to neonatal severe hyperbilirubinemia in Chinese Han population.","date":"2024","source":"BMC pediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/38279097","citation_count":5,"is_preprint":false},{"pmid":"1647290","id":"PMC_1647290","title":"Mapping of silver fox genes: chromosomal localization of the genes for GOT2, AK1, ALDOC, ACP1, ITPA, PGP, and BLVR.","date":"1991","source":"Cytogenetics and cell genetics","url":"https://pubmed.ncbi.nlm.nih.gov/1647290","citation_count":2,"is_preprint":false},{"pmid":"36688733","id":"PMC_36688733","title":"Protective effect of GK2 fused BLVRA protein against oxidative stress-induced dopaminergic neuronal cell damage.","date":"2023","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/36688733","citation_count":1,"is_preprint":false},{"pmid":"39468242","id":"PMC_39468242","title":"UGT1A1 and BLVRA allele and genotype variants in neonatal patients with hyperbilirubinemia in southern China.","date":"2024","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/39468242","citation_count":1,"is_preprint":false},{"pmid":"38216836","id":"PMC_38216836","title":"BLVRA exerts its biological effects to induce malignant properties of hepatocellular carcinoma cells via Wnt/β-catenin pathway.","date":"2024","source":"Journal of molecular histology","url":"https://pubmed.ncbi.nlm.nih.gov/38216836","citation_count":1,"is_preprint":false},{"pmid":"2074010","id":"PMC_2074010","title":"[Mapping of the silver fox genome. III. Determination of the chromosomal localization of the GOT2, AK1, ALDOC, ACP1, ITPA, PGP and BLVR genes].","date":"1990","source":"Genetika","url":"https://pubmed.ncbi.nlm.nih.gov/2074010","citation_count":1,"is_preprint":false},{"pmid":"41023045","id":"PMC_41023045","title":"BLVRA promotes glioblastoma progression by regulating fatty acid metabolism.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41023045","citation_count":0,"is_preprint":false},{"pmid":"39766828","id":"PMC_39766828","title":"Biliverdinuria Caused by Exonic BLVRA Deletions in Two Dogs with Green Urine.","date":"2024","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/39766828","citation_count":0,"is_preprint":false},{"pmid":"41530826","id":"PMC_41530826","title":"Multiomics analysis reveals that chlorogenic acid alleviates heat stress-induced oxidative damage in prepubertal boar testes via the BLVRA-GPX3 pathway: in vivo and in vitro evidence.","date":"2026","source":"Journal of animal science and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/41530826","citation_count":0,"is_preprint":false},{"pmid":"42018974","id":"PMC_42018974","title":"Understanding exacerbation risk in BLVR: A logistic regression approach to complication prediction.","date":"2026","source":"Chronic respiratory disease","url":"https://pubmed.ncbi.nlm.nih.gov/42018974","citation_count":0,"is_preprint":false},{"pmid":"42031091","id":"PMC_42031091","title":"Combined targeting of iron overload and BLVRA synergistically attenuates reactive astrocytes after subarachnoid hemorrhage.","date":"2026","source":"Experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/42031091","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.06.04.657936","title":"Biliverdin Reductase A is a major determinant of neuroprotective Nrf2 signaling","date":"2025-06-08","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.04.657936","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.10.18.619161","title":"Advanced deep-tissue imaging and manipulation enabled by biliverdin reductase knockout","date":"2024-10-18","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.18.619161","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.02.20.639306","title":"A Metabolite-Based Resistance Mechanism Against Malaria","date":"2025-02-26","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.20.639306","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":18442,"output_tokens":4264,"usd":0.059643,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12271,"output_tokens":4580,"usd":0.087928,"stage2_stop_reason":"end_turn"},"total_usd":0.147571,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1983,\n      \"finding\": \"BLVRA encodes a monomeric enzyme (~34 kDa) that uses both NADH and NADPH as cofactors, with both activities arising from a single gene product. Demonstrated by gel electrophoresis with chromogenic staining and somatic cell hybrid mapping.\",\n      \"method\": \"Gel electrophoresis with specific chromogenic staining; somatic cell hybrid complementation\",\n      \"journal\": \"Biochemical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct enzymatic assay demonstrating cofactor usage and monomeric structure, single lab but with orthogonal methods (electrophoresis + somatic cell hybrids)\",\n      \"pmids\": [\"6838484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"BVR-A catalyzes reduction of biliverdin IXα to bilirubin as a monomer (~34 kDa) using NADH; the reaction proceeds with B-face stereospecific oxidation of NADH, demonstrated by pre-steady-state burst kinetics with pH dependence.\",\n      \"method\": \"Recombinant GST-BVR-A fusion protein expression, gel filtration, in vitro enzymatic assay, stereospecificity assay with [4-³H]NADH\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstituted in vitro enzymatic activity with stereospecificity established by isotope labeling and pre-steady-state kinetics, single lab but multiple orthogonal in vitro methods\",\n      \"pmids\": [\"9359830\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"A homozygous nonsense mutation (c.214C>A, p.Ser44X) in BLVRA generates a truncated protein with no catalytic activity, leading to accumulation of biliverdin (hyperbiliverdinaemia) during cholestasis episodes. Complete absence of BVR-A activity is non-lethal.\",\n      \"method\": \"Site-directed mutagenesis, expression in human hepatoma liver cells and Xenopus laevis oocytes, immunoblotting, immunofluorescence, functional BVR-A activity assay\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — loss-of-function mutagenesis combined with enzymatic activity assay and heterologous expression in two cell systems, confirmed in human patients\",\n      \"pmids\": [\"21278388\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"BVRA mediates macrophage expression of the anti-inflammatory cytokine IL-10. BVRA overexpression increased IL-10 mRNA and protein levels, while BVRA knockdown decreased IL-10, without affecting TNF-α, indicating a specific IL-10 regulatory role in macrophages.\",\n      \"method\": \"Recombinant adenovirus-mediated BVRA overexpression and siRNA knockdown in bone marrow-derived macrophages; ELISA and mRNA quantification; in vivo renal ischemia-reperfusion injury model\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal gain- and loss-of-function in primary macrophages with in vivo validation, single lab\",\n      \"pmids\": [\"26393580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"BLVRA is a direct target of miR-222 at its 3'-UTR; miR-222 suppression increases BLVRA protein levels, and BLVRA overexpression promotes erythroid differentiation of K562 cells and CD34+ HPCs, while BLVRA silencing attenuates hemin-induced erythroid differentiation.\",\n      \"method\": \"Luciferase 3'-UTR reporter assay, miR-222 mimic/inhibitor transfection, siRNA knockdown, quantitative proteomics, erythroid differentiation assay\",\n      \"journal\": \"Cell biochemistry and function\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct 3'-UTR luciferase validation plus reciprocal gain/loss-of-function for differentiation phenotype, single lab\",\n      \"pmids\": [\"29368338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"BVRA-mediated biliverdin reduction to bilirubin inhibits TLR4 signaling in human leukocytes. Biliverdin triggers phosphorylation of mTORC2-specific targets (Akt, PKCζ, AMPKα-LKB1-TSC1/2) and their physical association with BVRA. TLR4 activation counter-suppresses BVRA expression, indicating a reciprocal regulatory axis.\",\n      \"method\": \"Phosphoprotein analysis (Western blot), co-immunoprecipitation of BVRA with mTORC2 targets, pharmacological inhibition (Torin, PP242, PKCζ inhibitory peptide), in vivo human samples (cardiopulmonary bypass patients, T2D patients)\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP and pharmacological dissection of pathway, human in vivo data supporting the model, single lab\",\n      \"pmids\": [\"31065010\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Loss of BVRA in hepatocytes (CRISPR-Cas9 knockout) causes reduced bilirubin production, increased ROS, lipid accumulation, decreased mitochondrial number, reduced mitochondrial biogenesis markers, and impaired oxidative phosphorylation, establishing BVRA as a protector against lipid accumulation and oxidative stress in hepatocytes.\",\n      \"method\": \"CRISPR-Cas9 gene knockout in murine hepa1c1c7 hepatocytes, enzymatic activity assay, lipid staining, ROS measurement, mitochondrial oxygen consumption assay, gene expression analysis\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with multiple orthogonal phenotypic readouts (ROS, lipid, mitochondria, respiration), single lab\",\n      \"pmids\": [\"31422074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Adipose-specific deletion of BVRA in mice leads to increased visceral fat, reduced mitochondrial number in white adipose tissue (WAT), increased adipocyte hypertrophy and inflammation, decreased expression of browning genes (Ppara, Adrb3), and impaired insulin signaling in WAT (reduced pAKT and Glut4 mRNA), establishing BVRA as a regulator of WAT mitochondrial function and insulin signaling.\",\n      \"method\": \"Adipose-specific conditional Blvra knockout mouse (BlvraFatKO), body composition analysis, histology, gene expression profiling, Western blot for pAKT\",\n      \"journal\": \"Biomolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — tissue-specific KO mouse with multiple orthogonal mechanistic readouts, single lab\",\n      \"pmids\": [\"32131495\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BVR-A deficiency in mouse brain cortex leads to mTOR hyperactivation and impairment of autophagy (reduced Beclin-1, LC3, LC3II/I ratio, Atg5-Atg12, Atg7), with dysregulated AMPK identified as the critical upstream driver of mTOR hyperactivation in the absence of BVR-A.\",\n      \"method\": \"BVR-A knockout mouse (BVR-A-/-), age-series cortex analysis (2, 6, 11 months), Western blot for mTOR/AMPK/autophagy pathway components, oxidative stress markers\",\n      \"journal\": \"Antioxidants (Basel, Switzerland)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO model with longitudinal mechanistic pathway analysis via Western blot, single lab\",\n      \"pmids\": [\"32727065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BLVRA overexpression in colorectal cancer cells activates Wnt/β-catenin signaling (upregulates c-MYC, β-catenin, Cyclin D1) to promote proliferation, migration, invasion, and EMT; BLVRA knockdown produces opposite effects and blocks pathway activation.\",\n      \"method\": \"Lentiviral overexpression and knockdown in HT-29 and SW620 CRC cells, Western blot for Wnt/β-catenin pathway targets, MTT proliferation assay, flow cytometry apoptosis, Transwell migration/invasion assay\",\n      \"journal\": \"Cancer management and research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — gain/loss-of-function with pathway target assessment by Western blot but no direct mechanistic link established between BLVRA enzymatic activity and Wnt pathway, single lab, single study\",\n      \"pmids\": [\"32425592\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Elevated BVRA in high-capacity running (HCR) rats correlates with higher plasma bilirubin and reduced UGT1A1, and increased PPARα target genes (Fgf21, Abcd3, Gys2), indicating that exercise-induced increases in bilirubin production involve upregulation of hepatic BVRA and suppression of UGT1A1.\",\n      \"method\": \"Genetically selected rat strains (HCR vs LCR), plasma bilirubin measurement, hepatic enzyme protein/activity quantification, gene expression analysis, PAS staining for glycogen\",\n      \"journal\": \"Antioxidants (Basel, Switzerland)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — correlative measurement in animal model without direct mechanistic intervention on BVRA itself, single lab\",\n      \"pmids\": [\"32961782\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"KRGE-induced BVR-A expression and subsequent bilirubin production in astrocytes regulates mitochondrial function (membrane potential, mass, oxidative phosphorylation) through LKB1, SIRT1, and ERRα, and modulates mitochondria-localized proteins (SIRT5, Tom20, Tom22, cytochrome c, SOD2). This BVR-A-LKB1-SIRT1-ERRα pathway was AMPKα-independent.\",\n      \"method\": \"KRGE treatment of hippocampal astrocytes in vivo (mice) and in vitro, BVR-A knockdown/overexpression, mitochondrial membrane potential assay, Western blot for pathway components, immunofluorescence\",\n      \"journal\": \"Antioxidants (Basel, Switzerland)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pathway placement via KD/OE with multiple readouts but mechanism is indirect (bilirubin-mediated), single lab, single study\",\n      \"pmids\": [\"36139815\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"GK2-BLVRA fusion protein (using a novel protein transduction domain) transduces into dopaminergic neurons, suppresses MAPK activation, modulates apoptosis-related proteins (Bcl-2, Bax, caspase-3/-9), reduces ROS and DNA damage after MPP+ exposure, and reduces dopaminergic neuronal death in MPTP-treated mice, demonstrating that BLVRA antioxidant activity protects dopaminergic neurons.\",\n      \"method\": \"Recombinant fusion protein transduction into SH-SY5Y cells and in vivo MPTP mouse model; Western blot for MAPK and apoptosis proteins; ROS measurement; immunohistochemistry for dopaminergic neurons\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein delivery with mechanistic readouts in both in vitro and in vivo PD models, single lab\",\n      \"pmids\": [\"36688733\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"BLVRA knockdown in HCC cells (HepG2, Hep3B) suppresses proliferation, cell cycle progression, invasion, migration, and induces apoptosis, with reduction of Wnt/β-catenin targets (c-MYC, β-catenin, Cyclin D1); WNT inhibitor IWP-4 phenocopies BLVRA knockdown, placing BLVRA upstream of Wnt/β-catenin in HCC.\",\n      \"method\": \"siRNA knockdown in HCC cell lines, Western blot for Wnt/β-catenin pathway, cell proliferation and apoptosis assays, pharmacological Wnt inhibition (IWP-4), invasion/migration assays\",\n      \"journal\": \"Journal of molecular histology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — KD with pharmacological epistasis supporting Wnt pathway placement, but no direct biochemical link between BLVRA and pathway components established, single lab\",\n      \"pmids\": [\"38216836\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Homozygous large deletions in canine BLVRA causing predicted truncations result in loss of BVR-A enzymatic function and biliverdinuria, confirming that BLVRA loss-of-function causes biliverdin accumulation in a non-human mammal.\",\n      \"method\": \"Whole genome sequencing, Sanger sequencing, urinary mass spectrometry for biliverdin quantification in dogs\",\n      \"journal\": \"Genes\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genomic deletion confirmed by two sequencing methods with direct metabolite measurement, ortholog of human BLVRA, replicates human inactivating mutation finding\",\n      \"pmids\": [\"39766828\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"BVRA directly interacts with Nrf2 (the master redox transcription factor) in a non-enzymatic capacity, modulating the expression of neuroprotective Nrf2 target genes including those dysregulated in Alzheimer's disease, as revealed by ChIP-seq and RNA-seq.\",\n      \"method\": \"Co-immunoprecipitation/direct interaction assay, ChIP-seq, RNA-seq in brain cells; BVRA knockout model comparison\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein-protein interaction plus genome-wide transcriptional analysis (ChIP-seq/RNA-seq), preprint not yet peer-reviewed, single lab\",\n      \"pmids\": [\"bio_10.1101_2025.06.04.657936\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"BLVRA encodes biliverdin reductase A, a monomeric cytosolic enzyme that catalyzes B-face stereospecific reduction of biliverdin IXα to bilirubin using NADH or NADPH; beyond this enzymatic role it functions as a signaling scaffold that physically associates with mTORC2 targets (Akt, PKCζ, AMPK) to suppress TLR4-driven inflammation, regulates the AMPK/mTOR/autophagy axis in the brain, promotes IL-10 production in macrophages, supports mitochondrial biogenesis and insulin signaling in adipocytes and hepatocytes, promotes erythroid differentiation, and non-enzymatically interacts with Nrf2 to coordinate neuroprotective gene expression.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"BLVRA encodes biliverdin reductase A, a monomeric ~34 kDa cytosolic enzyme that catalyzes the B-face stereospecific reduction of biliverdin IXα to bilirubin using either NADH or NADPH, with both cofactor activities arising from a single gene product [#0, #1]. Complete loss of catalytic activity through nonsense or large deletion mutations causes biliverdin accumulation (hyperbiliverdinaemia/biliverdinuria) and is non-lethal in both humans and dogs [#2, #14]. Beyond bilirubin synthesis, BVRA serves as a signaling node that physically associates with mTORC2-pathway components (Akt, PKCζ, the AMPKα–LKB1–TSC1/2 module) to restrain TLR4-driven inflammation in leukocytes, a reciprocally regulated axis in which TLR4 activation suppresses BVRA [#5], and it specifically promotes anti-inflammatory IL-10 expression in macrophages [#3]. Through its bilirubin-generating and signaling functions BVRA protects cells from oxidative stress and supports mitochondrial biogenesis and oxidative phosphorylation in hepatocytes and adipocytes, where its loss produces lipid accumulation, mitochondrial deficits, and impaired insulin signaling [#6, #7]. In brain, BVRA constrains mTOR activity and sustains autophagy via AMPK, and protects neurons against oxidative damage [#8, #12]. BVRA also acts on cell-fate programs, being required for hemin-induced erythroid differentiation downstream of miR-222 regulation [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1983,\n      \"claim\": \"Established that a single BLVRA gene product is a monomeric enzyme able to use both NADH and NADPH, resolving whether the dual-cofactor activity reflected one or two enzymes.\",\n      \"evidence\": \"Gel electrophoresis with chromogenic staining and somatic cell hybrid mapping\",\n      \"pmids\": [\"6838484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Catalytic mechanism and stereochemistry not addressed\", \"No recombinant reconstitution\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Defined the enzymatic mechanism, showing BVR-A reduces biliverdin IXα to bilirubin with B-face stereospecific oxidation of NADH, establishing the chemistry of the core reaction.\",\n      \"evidence\": \"Recombinant GST-BVR-A, gel filtration, in vitro assay, [4-³H]NADH stereospecificity, pre-steady-state burst kinetics\",\n      \"pmids\": [\"9359830\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of stereospecificity not resolved\", \"Physiological consequences of bilirubin production not addressed\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrated that complete loss of BVR-A activity in humans causes biliverdin accumulation but is non-lethal, defining the in vivo consequence of enzyme failure.\",\n      \"evidence\": \"Site-directed mutagenesis of c.214C>A (p.Ser44X), heterologous expression in hepatoma cells and Xenopus oocytes, activity assay, human patients\",\n      \"pmids\": [\"21278388\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why loss is tolerated despite proposed signaling roles is unexplained\", \"Non-enzymatic functions not tested in patients\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Showed BVRA selectively drives macrophage IL-10 expression without affecting TNF-α, identifying a specific anti-inflammatory regulatory role.\",\n      \"evidence\": \"Adenoviral overexpression and siRNA knockdown in BMDMs, ELISA/mRNA, in vivo renal ischemia-reperfusion\",\n      \"pmids\": [\"26393580\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular link between BVRA and IL-10 transcription not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Placed BLVRA in a post-transcriptional regulatory circuit (miR-222 target) and showed it is required for erythroid differentiation, connecting the enzyme to cell-fate control.\",\n      \"evidence\": \"3'-UTR luciferase reporter, miR-222 mimic/inhibitor, siRNA, quantitative proteomics, erythroid differentiation of K562 and CD34+ cells\",\n      \"pmids\": [\"29368338\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the differentiation effect requires enzymatic activity unknown\", \"Downstream effectors not identified\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined BVRA as a signaling scaffold that physically engages mTORC2 targets (Akt, PKCζ, AMPKα-LKB1-TSC1/2) to suppress TLR4 inflammation, revealing a non-canonical, reciprocally regulated function.\",\n      \"evidence\": \"Phosphoprotein Western blot, Co-IP of BVRA with mTORC2 targets, pharmacological inhibition (Torin, PP242, PKCζ peptide), human bypass and T2D samples\",\n      \"pmids\": [\"31065010\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binding interfaces not mapped\", \"Single lab without reciprocal structural validation\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Established BVRA as a protector against hepatocyte lipid accumulation and oxidative stress through support of mitochondrial biogenesis and respiration.\",\n      \"evidence\": \"CRISPR-Cas9 knockout in hepa1c1c7 cells, activity assay, lipid/ROS staining, mitochondrial respiration, gene expression\",\n      \"pmids\": [\"31422074\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Enzymatic vs scaffold contribution to mitochondrial phenotype not separated\", \"Single cell model\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended BVRA's metabolic role to adipose tissue, showing adipose-specific deletion impairs WAT mitochondrial function and insulin signaling and promotes adiposity and inflammation.\",\n      \"evidence\": \"Adipose-specific Blvra knockout mice, body composition, histology, expression profiling, pAKT Western blot\",\n      \"pmids\": [\"32131495\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Upstream mechanism linking BVRA to browning genes not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed BVR-A deficiency in brain cortex hyperactivates mTOR and impairs autophagy with dysregulated AMPK as the upstream driver, defining a neural AMPK/mTOR/autophagy role.\",\n      \"evidence\": \"BVR-A knockout mice, longitudinal cortex analysis, Western blot for mTOR/AMPK/autophagy markers\",\n      \"pmids\": [\"32727065\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How BVRA controls AMPK mechanistically unresolved\", \"Behavioral/cognitive outcomes not linked\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked BLVRA to Wnt/β-catenin signaling and proliferation in colorectal cancer cells via gain/loss-of-function.\",\n      \"evidence\": \"Lentiviral overexpression/knockdown in HT-29 and SW620, Western blot, proliferation/migration/invasion assays\",\n      \"pmids\": [\"32425592\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct biochemical link between BLVRA and Wnt components established\", \"Single study, single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Correlated exercise-associated hepatic BVRA upregulation with elevated bilirubin and PPARα target genes in a selected rat model.\",\n      \"evidence\": \"HCR vs LCR rat strains, plasma bilirubin, hepatic enzyme quantification, gene expression\",\n      \"pmids\": [\"32961782\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Correlative only, no direct intervention on BVRA\", \"Causality unestablished\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed BVR-A in an AMPKα-independent LKB1-SIRT1-ERRα axis controlling astrocyte mitochondrial function via bilirubin production.\",\n      \"evidence\": \"KRGE treatment of astrocytes in vivo/in vitro, BVR-A KD/OE, mitochondrial membrane potential, Western blot, immunofluorescence\",\n      \"pmids\": [\"36139815\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Mechanism is indirect via bilirubin\", \"Single study, single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Demonstrated that delivered BLVRA antioxidant activity protects dopaminergic neurons by suppressing MAPK and apoptotic signaling in PD models.\",\n      \"evidence\": \"GK2-BLVRA fusion protein transduction into SH-SY5Y and MPTP mice, Western blot, ROS, immunohistochemistry\",\n      \"pmids\": [\"36688733\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether endogenous BVRA confers the same protection not tested\", \"Distinction between enzymatic and scaffold contribution unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Confirmed in a second mammal (dog) that BLVRA loss-of-function causes biliverdin accumulation, generalizing the human enzymatic-deficiency phenotype.\",\n      \"evidence\": \"Whole genome and Sanger sequencing, urinary mass spectrometry for biliverdin in dogs\",\n      \"pmids\": [\"39766828\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Non-enzymatic functions not assessed in this ortholog\", \"Systemic consequences not characterized\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Reinforced BLVRA's upstream role in Wnt/β-catenin signaling in hepatocellular carcinoma using pharmacological epistasis.\",\n      \"evidence\": \"siRNA knockdown in HepG2/Hep3B, Western blot, proliferation/apoptosis assays, Wnt inhibitor IWP-4 epistasis\",\n      \"pmids\": [\"38216836\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct biochemical interaction with Wnt components shown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed a non-enzymatic role for BVRA as a direct Nrf2 partner shaping neuroprotective transcriptional output, expanding its function into redox gene regulation.\",\n      \"evidence\": \"Co-IP/interaction assay, ChIP-seq, RNA-seq in brain cells with BVRA knockout comparison (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.06.04.657936\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Direct binding interface and mechanism of transcriptional modulation not defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how BVRA's enzymatic (bilirubin-producing) and non-enzymatic (scaffold/transcriptional) functions are mechanistically partitioned and which underlies each tissue-specific phenotype.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model distinguishing catalytic vs interaction surfaces\", \"Causal separation of enzyme vs scaffold roles not achieved across tissues\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016491\", \"supporting_discovery_ids\": [0, 1, 2, 6, 14]},\n      {\"term_id\": \"GO:0016209\", \"supporting_discovery_ids\": [6, 12]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 2, 6, 7]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [3, 5]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [6, 8, 12]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"AKT1\", \"PRKCZ\", \"PRKAA1\", \"STK11\", \"NFE2L2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}