title: Dissection of platelet and myeloid cell defects by conditional targeting of the beta3-integrin subunit.
abstract: The purpose of this work was to determine platelet and myeloid cell-specific requirements for beta3-containing integrins in hemostasis, bone resorption, and tumor growth. LoxP-flanked mice were generated to study the conditional deletion of beta3-integrin in platelets [knockout in platelets (KOP)] and myeloid cells [knockout in myeloid (KOM)]. Using the beta3KOP and beta3KOM strains of mice, we studied the role of beta3-integrin in hemostasis, bone resorption, and subcutaneous tumor growth. Tissue-specific deletion of platelet beta3-integrins in beta3KOP mice did not affect bone mass but resulted in a severe bleeding phenotype. No growth difference of tumor xenografts or in neoangiogenesis were found in beta3KOP mice, in contrast to the defects observed in germline beta3(-/-) mice. Conditional deletion of myeloid beta3-integrins in beta3KOM mice resulted in osteopetrosis but had no effect on hemostasis or mortality. Tumor growth in beta3KOM mice was increased and accompanied by decreased macrophage infiltration, without increase in blood vessel number. Platelet beta3-integrin deficiency was sufficient to disrupt hemostasis but had no effect on bone mass or tumor growth. Myeloid-specific beta3-integrin deletion was sufficient to perturb bone mass and enhance tumor growth due to reduced macrophage infiltration in the tumors. These results suggest that beta3-integrins have cell-specific roles in complex biological processes.-Morgan, E. A., Schneider, J. G., Baroni, T. E., Uluçkan, O., Heller, E., Hurchla, M. A., Deng, H., Floyd, D., Berdy, A., Prior, J. L., Piwnica-Worms, D., Teitelbaum, S. L., Ross, F. P., Weilbaecher, K. N. Dissection of platelet and myeloid cell defects by conditional targeting of the beta3-integrin subunit.
authors.affiliation: Department of Medicine, Mallinkrodt Institute of Radiology, St. Louis, Missouri, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Morgan
authors.forename: Jochen G
authors.initials: JG
authors.lastname: Schneider
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Baroni
authors.forename: Ozge
authors.initials: O
authors.lastname: Uluçkan
authors.forename: Emanuela
authors.initials: E
authors.lastname: Heller
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Hurchla
authors.forename: Hongju
authors.initials: H
authors.lastname: Deng
authors.forename: Desiree
authors.initials: D
authors.lastname: Floyd
authors.forename: Andrew
authors.initials: A
authors.lastname: Berdy
authors.forename: Julie L
authors.initials: JL
authors.lastname: Prior
authors.forename: David
authors.initials: D
authors.lastname: Piwnica-Worms
authors.forename: Steven L
authors.initials: SL
authors.lastname: Teitelbaum
authors.forename: F Patrick
authors.initials: FP
authors.lastname: Ross
authors.forename: Katherine N
authors.initials: KN
authors.lastname: Weilbaecher
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism* / Q000473:pathology; D001862:Bone Resorption / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D006470:Hemorrhage / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006487:Hemostasis; D006801:Humans; D039661:Integrin beta3 / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D009368:Neoplasm Transplantation; D009928:Organ Specificity / Q000235:genetics; D014183:Transplantation, Heterologous
chemical_list: D039661:Integrin beta3