title: Hypercholesterolemia promotes bone marrow cell mobilization by perturbing the SDF-1:CXCR4 axis.
abstract: Hypercholesterolemia is associated with elevated peripheral blood leukocytes and increased platelet levels, generally attributed to cholesterol-induced proinflammatory cytokines. Bone marrow (BM) cell mobilization and platelet production is achieved by disrupting the SDF-1:CXCR4 axis, namely with granulocyte colony-stimulating factor and/or CXCR4 antagonists. Here we show that high cholesterol disrupts the BM SDF-1:CXCR4 axis; promotes the mobilization of B cells, neutrophils, and progenitor cells (HPCs); and creates thrombocytosis. Hypercholesterolemia was achieved after a 30-day high-cholesterol feeding trial, resulting in elevated low-density lipoprotein (LDL) cholesterol levels and inversion of the LDL to high-density lipoprotein cholesterol ratio. Hypercholesterolemic mice displayed lymphocytosis, increased neutrophils, HPCs, and thrombocytosis with a lineage-specific decrease in the BM. Histologic analysis revealed that megakaryocyte numbers remained unaltered but, in high-cholesterol mice, they formed large clusters in contact with BM vessels. In vitro, LDL induced stromal cell-derived factor-1 (SDF-1) production, suggesting that megakaryocyte delocalization resulted from an altered SDF-1 gradient. LDL also stimulated B cells and HPC migration toward SDF-1, which was blocked by scavenger receptor class B type I (cholesterol receptor) inhibition. Accordingly, hypercholesterolemic mice had increased peripheral blood SDF-1 levels, increased platelets, CXCR4-positive B lymphocytes, neutrophils, and HPCs. High cholesterol interferes with the BM SDF-1:CXCR4 axis, resulting in lymphocytosis, thrombocytosis, and HPC mobilization.
authors.affiliation: Angiogenesis Group, Instituto Português de Oncologia de Francisco Gentil, Centro de Lisboa, EPE (CIPM/IPOLFG), Lisboa, Portugal. sergidias@ipolisboa.min-saude.pt
authors.forename: Ana L
authors.initials: AL
authors.lastname: Gomes
authors.forename: Tânia
authors.initials: T
authors.lastname: Carvalho
authors.forename: Jacinta
authors.initials: J
authors.lastname: Serpa
authors.forename: Cheila
authors.initials: C
authors.lastname: Torre
authors.forename: Sérgio
authors.initials: S
authors.lastname: Dias
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000378:metabolism*; D002454:Cell Differentiation; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D019650:Hematopoietic Stem Cell Mobilization; D006801:Humans; D006937:Hypercholesterolemia / Q000378:metabolism / Q000473:pathology*; D007124:Immunoenzyme Techniques; D008156:Luciferases / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism
chemical_list: D054377:Chemokine CXCL12; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D008156:Luciferases