{"doi":"10.1101/2025.09.17.676962","title":"CYB5R4 sustains endothelial proliferation and ischemia-induced angiogenesis by maintaining RRM2-dependent nucleotide balance","abstract":"Abstract Angiogenesis is essential for revascularization in peripheral artery disease (PAD), yet pro-angiogenic therapies remain inconsistent. Here, we identify a cytosolic reductase, CYB5R4, as an intrinsic regulator of endothelial proliferation and ischemia-induced angiogenesis. In mice, global haploinsufficiency or inducible endothelial deletion of Cyb5r4 delayed perfusion recovery after femoral artery ligation and reduced capillary expansion. CYB5R4 is known to promote stearoyl-CoA desaturase (SCD) activity and is required for the de novo synthesis of monounsaturated fatty acids. In human endothelial cells, CYB5R4 silencing impaired proliferation with G1-S arrest that was not rescued by monounsaturated fatty acids and differed from the loss of SCD, indicating an SCD-independent mechanism. RNA sequencing with Bayesian network inference highlighted the ribonucleotide-reductase subunit RRM2 as a key downstream mediator. RRM2 overexpression partially restored proliferation. Integrated untargeted metabolomics and targeted nucleotide quantification revealed an imbalanced nucleotide pool in CYB5R4-deficient cells. These findings support a model in which CYB5R4 sustains endothelial proliferation and ischemia-driven angiogenesis by maintaining RRM2-dependent nucleotide balance. Targeting the CYB5R4-RRM2 axis may improve therapeutic angiogenesis in PAD.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":575382,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9538,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":384379,"name":"Scott Hahn","orcid":null,"position":1,"is_corresponding":false},{"id":1483678,"name":"Colussi C Nicole","orcid":null,"position":2,"is_corresponding":false},{"id":237068,"name":"Steven J. Mullett","orcid":"0009-0005-6971-9288","position":3,"is_corresponding":false},{"id":237076,"name":"Stacy G. Wendell","orcid":"0000-0001-9083-6933","position":4,"is_corresponding":false},{"id":1483679,"name":"Francisco J. Schopfer","orcid":null,"position":5,"is_corresponding":false},{"id":351853,"name":"Adam C. Straub","orcid":"0000-0003-0542-9466","position":6,"is_corresponding":false},{"id":507105,"name":"Shuai Yuan","orcid":"0000-0002-9590-6555","position":0,"is_corresponding":true}],"reference_count":47,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T02:57:48.486077Z","pmid":"41000936","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}