title: In Vivo Visualization of Stromal Macrophages via label-free FLIM-based metabolite imaging.
abstract: Macrophage infiltration and recruitment in breast tumors has been correlated with poor prognosis in breast cancer patients and has been linked to tumor cell dissemination. Much of our understanding comes from animal models in which macrophages are labeled by expression of an extrinsic fluorophore. However, conventional extrinsic fluorescence labeling approaches are not readily applied to human tissue and clinical use. We report a novel strategy that exploits endogenous fluorescence from the metabolic co-factors NADH and FAD with quantitation from Fluorescence Lifetime Imaging Microscopy (FLIM) as a means to non-invasively identify tumor-associated macrophages in the intact mammary tumor microenvironment. Macrophages were FAD(HI) and demonstrated a glycolytic-like NADH-FLIM signature that was readily separated from the intrinsic fluorescence signature of tumor cells. This non-invasive quantitative technique provides a unique ability to discern specific cell types based upon their metabolic signatures without the use of exogenous fluorescent labels. Not only does this provide high resolution temporal and spatial views of macrophages in live animal breast cancer models, this approach can be extended to other animal disease models where macrophages are implicated and has potential for clinical applications.
authors.affiliation: Molecular and Cellular Pharmacology Graduate Program, UW-Madison, Madison, WI, USA.|Department of Cell and Regenerative Biology, School of Medicine and Public Health, UW-Madison, Madison, WI, USA.|Laboratory for Optical and Computational Instrumentation, UW-Madison, Madison, WI, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Szulczewski
authors.affiliation: Department of Cell and Regenerative Biology, School of Medicine and Public Health, UW-Madison, Madison, WI, USA.|Laboratory for Optical and Computational Instrumentation, UW-Madison, Madison, WI, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Inman
authors.affiliation: Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY, USA.
authors.forename: David
authors.initials: D
authors.lastname: Entenberg
authors.affiliation: Department of Cell and Regenerative Biology, School of Medicine and Public Health, UW-Madison, Madison, WI, USA.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Ponik
authors.affiliation: Department of Medicine, Mount Sinai, New York NY, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Aguirre-Ghiso
authors.affiliation: College of Nanoscale Science and Engineering, SUNY Polytechnic University, Albany, NY, USA.
authors.forename: James
authors.initials: J
authors.lastname: Castracane
authors.affiliation: Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY, USA.
authors.forename: John
authors.initials: J
authors.lastname: Condeelis
authors.affiliation: Laboratory for Optical and Computational Instrumentation, UW-Madison, Madison, WI, USA.
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Eliceiri
authors.affiliation: Molecular and Cellular Pharmacology Graduate Program, UW-Madison, Madison, WI, USA.|Department of Cell and Regenerative Biology, School of Medicine and Public Health, UW-Madison, Madison, WI, USA.|Laboratory for Optical and Computational Instrumentation, UW-Madison, Madison, WI, USA.
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Keely
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis; D006801:Humans; D008264:Macrophages / Q000166:cytology*; D008856:Microscopy, Fluorescence / Q000379:methods*; D009243:NAD / Q000032:analysis; D061848:Optical Imaging / Q000379:methods*
chemical_list: D009243:NAD; D005182:Flavin-Adenine Dinucleotide