1
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Singh RK, Haka AS, Bhardwaj P, Zha X, Maxfield FR. Dynamic Actin Reorganization and Vav/Cdc42-Dependent Actin Polymerization Promote Macrophage Aggregated LDL (Low-Density Lipoprotein) Uptake and Catabolism. Arterioscler Thromb Vasc Biol 2019; 39:137-149. [PMID: 30580573 DOI: 10.1161/atvbaha.118.312087] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Objective- During atherosclerosis, LDLs (low-density lipoproteins) accumulate in the arteries, where they become modified, aggregated, and retained. Such deposits of aggregated LDL (agLDL) can be recognized by macrophages, which attempt to digest and clear them. AgLDL catabolism promotes internalization of cholesterol and foam cell formation, which leads to the progression of atherosclerosis. Therapeutic blockade of this process may delay disease progression. When macrophages interact with agLDL in vitro, they form a novel extracellular, hydrolytic compartment-the lysosomal synapse (LS)-aided by local actin polymerization to digest agLDL. Here, we investigated the specific regulators involved in actin polymerization during the formation of the LS. Approach and Results- We demonstrate in vivo that atherosclerotic plaque macrophages contacting agLDL deposits polymerize actin and form a compartment strikingly similar to those made in vitro. Live cell imaging revealed that macrophage cortical F-actin depolymerization is required for actin polymerization to support the formation of the LS. This depolymerization is cofilin-1 dependent. Using siRNA-mediated silencing, pharmacological inhibition, genetic knockout, and stable overexpression, we elucidate key roles for Cdc42 Rho GTPase and GEF (guanine nucleotide exchange factor) Vav in promoting actin polymerization during the formation of the LS and exclude a role for Rac1. Conclusions- These results highlight critical roles for dynamic macrophage F-actin rearrangement and polymerization via cofilin-1, Vav, and Cdc42 in LS formation, catabolism of agLDL, and foam cell formation. These proteins might represent therapeutic targets to treat atherosclerotic disease.
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Affiliation(s)
- Rajesh K Singh
- From the Department of Biochemistry, Weill Cornell Medical College, New York (R.K.S., A.S.H., P.B., F.R.M.)
| | - Abigail S Haka
- From the Department of Biochemistry, Weill Cornell Medical College, New York (R.K.S., A.S.H., P.B., F.R.M.)
| | - Priya Bhardwaj
- From the Department of Biochemistry, Weill Cornell Medical College, New York (R.K.S., A.S.H., P.B., F.R.M.)
| | - Xiaohui Zha
- Department of Biochemistry, Microbiology, and Immunology (X.Z.), University of Ottawa, ON, Canada.,Department of Medicine (X.Z.), University of Ottawa, ON, Canada.,Chronic Disease Program, Ottawa Hospital Research Institute, ON, Canada (X.Z.)
| | - Frederick R Maxfield
- From the Department of Biochemistry, Weill Cornell Medical College, New York (R.K.S., A.S.H., P.B., F.R.M.)
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2
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Singh RK, Lund FW, Haka AS, Maxfield FR. High-density lipoprotein or cyclodextrin extraction of cholesterol from aggregated LDL reduces foam cell formation. J Cell Sci 2019; 132:jcs.237271. [PMID: 31719160 DOI: 10.1242/jcs.237271] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/05/2019] [Indexed: 01/29/2023] Open
Abstract
Low-density lipoprotein (LDL) deposition, aggregation and retention in the endothelial sub-intima are critical initiating events during atherosclerosis. Macrophages digest aggregated LDL (agLDL) through a process called exophagy. High-density lipoprotein (HDL) plays an atheroprotective role, but studies attempting to exploit it therapeutically have been unsuccessful, highlighting gaps in our current understanding of HDL function. Here, we characterized the role of HDL during exophagy of agLDL. We find that atherosclerotic plaque macrophages contact agLDL and form an extracellular digestive compartment similar to that observed in vitro During macrophage catabolism of agLDL in vitro, levels of free cholesterol in the agLDL are increased. HDL can extract free cholesterol directly from this agLDL and inhibit macrophage foam cell formation. Cholesterol-balanced hydroxypropyl-β-cyclodextrin similarly reduced macrophage cholesterol uptake and foam cell formation. Finally, we show that HDL can directly extract free cholesterol, but not cholesterol esters, from agLDL in the absence of cells. Together, these results suggest that the actions of HDL can directly extract free cholesterol from agLDL during catabolism, and provide a new context in which to view the complex relationship between HDL and atherosclerosis.
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Affiliation(s)
- Rajesh K Singh
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Frederik W Lund
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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3
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Singh RK, Haka AS, Asmal A, Barbosa-Lorenzi VC, Grosheva I, Chin HF, Xiong Y, Hla T, Maxfield FR. TLR4 (Toll-Like Receptor 4)-Dependent Signaling Drives Extracellular Catabolism of LDL (Low-Density Lipoprotein) Aggregates. Arterioscler Thromb Vasc Biol 2019; 40:86-102. [PMID: 31597445 DOI: 10.1161/atvbaha.119.313200] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Aggregation and modification of LDLs (low-density lipoproteins) promote their retention and accumulation in the arteries. This is a critical initiating factor during atherosclerosis. Macrophage catabolism of agLDL (aggregated LDL) occurs using a specialized extracellular, hydrolytic compartment, the lysosomal synapse. Compartment formation by local actin polymerization and delivery of lysosomal contents by exocytosis promotes acidification of the compartment and degradation of agLDL. Internalization of metabolites, such as cholesterol, promotes foam cell formation, a process that drives atherogenesis. Furthermore, there is accumulating evidence for the involvement of TLR4 (Toll-like receptor 4) and its adaptor protein MyD88 (myeloid differentiation primary response 88) in atherosclerosis. Here, we investigated the role of TLR4 in catabolism of agLDL using the lysosomal synapse and foam cell formation. Approach and Results: Using bone marrow-derived macrophages from knockout mice, we find that TLR4 and MyD88 regulate compartment formation, lysosome exocytosis, acidification of the compartment, and foam cell formation. Using siRNA (small interfering RNA), pharmacological inhibition and knockout bone marrow-derived macrophages, we implicate SYK (spleen tyrosine kinase), PI3K (phosphoinositide 3-kinase), and Akt in agLDL catabolism using the lysosomal synapse. Using bone marrow transplantation of LDL receptor knockout mice with TLR4 knockout bone marrow, we show that deficiency of TLR4 protects macrophages from lipid accumulation during atherosclerosis. Finally, we demonstrate that macrophages in vivo form an extracellular compartment and exocytose lysosome contents similar to that observed in vitro for degradation of agLDL. CONCLUSIONS We present a mechanism in which interaction of macrophages with agLDL initiates a TLR4 signaling pathway, resulting in formation of the lysosomal synapse, catabolism of agLDL, and lipid accumulation in vitro and in vivo.
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Affiliation(s)
- Rajesh K Singh
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
| | - Abigail S Haka
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
| | - Arky Asmal
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
| | - Valéria C Barbosa-Lorenzi
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
| | - Inna Grosheva
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
| | - Harvey F Chin
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
| | - Yuquan Xiong
- Vascular Biology Program, Boston Children's Hospital and Department of Surgery, Harvard Medical School, Boston, MA (Y.X., T.H.).,Current address: Thoracic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY (Y.X.)
| | - Timothy Hla
- Vascular Biology Program, Boston Children's Hospital and Department of Surgery, Harvard Medical School, Boston, MA (Y.X., T.H.)
| | - Frederick R Maxfield
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (R.K.S., A.S.H., A.A., V.C.B.-L., I.G., H.F.C., F.R.M.)
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4
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Singh RK, Haka AS, Bhardwaj P, Maxfield FR. Dynamic Actin Reorganization and Vav/Cdc42‐dependent Actin Polymerization Promote Macrophage Aggregated LDL Uptake and Catabolism. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.539.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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5
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Jena P, Roxbury D, Galassi TV, Akkari L, Horoszko CP, Iaea DB, Budhathoki-Uprety J, Pipalia N, Haka AS, Harvey JD, Mittal J, Maxfield FR, Joyce JA, Heller DA. A Carbon Nanotube Optical Reporter Maps Endolysosomal Lipid Flux. ACS Nano 2017; 11:10689-10703. [PMID: 28898055 PMCID: PMC5707631 DOI: 10.1021/acsnano.7b04743] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/31/2017] [Indexed: 05/18/2023]
Abstract
Lipid accumulation within the lumen of endolysosomal vesicles is observed in various pathologies including atherosclerosis, liver disease, neurological disorders, lysosomal storage disorders, and cancer. Current methods cannot measure lipid flux specifically within the lysosomal lumen of live cells. We developed an optical reporter, composed of a photoluminescent carbon nanotube of a single chirality, that responds to lipid accumulation via modulation of the nanotube's optical band gap. The engineered nanomaterial, composed of short, single-stranded DNA and a single nanotube chirality, localizes exclusively to the lumen of endolysosomal organelles without adversely affecting cell viability or proliferation or organelle morphology, integrity, or function. The emission wavelength of the reporter can be spatially resolved from within the endolysosomal lumen to generate quantitative maps of lipid content in live cells. Endolysosomal lipid accumulation in cell lines, an example of drug-induced phospholipidosis, was observed for multiple drugs in macrophages, and measurements of patient-derived Niemann-Pick type C fibroblasts identified lipid accumulation and phenotypic reversal of this lysosomal storage disease. Single-cell measurements using the reporter discerned subcellular differences in equilibrium lipid content, illuminating significant intracellular heterogeneity among endolysosomal organelles of differentiating bone-marrow-derived monocytes. Single-cell kinetics of lipoprotein-derived cholesterol accumulation within macrophages revealed rates that differed among cells by an order of magnitude. This carbon nanotube optical reporter of endolysosomal lipid content in live cells confers additional capabilities for drug development processes and the investigation of lipid-linked diseases.
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Affiliation(s)
- Prakrit
V. Jena
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Daniel Roxbury
- Department
of Chemical Engineering, University of Rhode
Island, Kingston, Rhode Island 02881, United States
| | - Thomas V. Galassi
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
- Weill
Cornell Medicine, New York, New York 10065, United States
| | - Leila Akkari
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
- Division
of Tumor Biology & Immunology, The Netherlands
Cancer Institute, Amsterdam 1066 CX, The Netherlands
| | - Christopher P. Horoszko
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
- Weill
Cornell Medicine, New York, New York 10065, United States
| | - David B. Iaea
- Weill
Cornell Medicine, New York, New York 10065, United States
| | | | - Nina Pipalia
- Weill
Cornell Medicine, New York, New York 10065, United States
| | - Abigail S. Haka
- Weill
Cornell Medicine, New York, New York 10065, United States
| | - Jackson D. Harvey
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
- Weill
Cornell Medicine, New York, New York 10065, United States
| | - Jeetain Mittal
- Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | | | - Johanna A. Joyce
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
- Weill
Cornell Medicine, New York, New York 10065, United States
- Ludwig Center
for Cancer Research, University of Lausanne, Lausanne CH 1066, Switzerland
| | - Daniel A. Heller
- Memorial
Sloan Kettering Cancer Center, New York, New York 10065, United States
- Weill
Cornell Medicine, New York, New York 10065, United States
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6
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Singh RK, Haka AS, Brumfield A, Grosheva I, Bhardwaj P, Chin HF, Xiong Y, Hla T, Maxfield FR. Ceramide activation of RhoA/Rho kinase impairs actin polymerization during aggregated LDL catabolism. J Lipid Res 2017; 58:1977-1987. [PMID: 28814641 PMCID: PMC5625121 DOI: 10.1194/jlr.m076398] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 08/11/2017] [Indexed: 01/22/2023] Open
Abstract
Macrophages use an extracellular, hydrolytic compartment formed by local actin polymerization to digest aggregated LDL (agLDL). Catabolism of agLDL promotes foam cell formation and creates an environment rich in LDL catabolites, including cholesterol and ceramide. Increased ceramide levels are present in lesional LDL, but the effect of ceramide on macrophage proatherogenic processes remains unknown. Here, we show that macrophages accumulate ceramide in atherosclerotic lesions. Using macrophages from sphingosine kinase 2 KO (SK2KO) mice to mimic ceramide-rich conditions of atherosclerotic lesions, we show that SK2KO macrophages display impaired actin polymerization and foam cell formation in response to contact with agLDL. C16-ceramide treatment impaired wild-type but not SK2KO macrophage actin polymerization, confirming that this effect is due to increased ceramide levels. We demonstrate that knockdown of RhoA or inhibition of Rho kinase restores agLDL-induced actin polymerization in SK2KO macrophages. Activation of RhoA in macrophages was sufficient to impair actin polymerization and foam cell formation in response to agLDL. Finally, we establish that during catabolism, macrophages take up ceramide from agLDL, and inhibition of ceramide generation modulates actin polymerization. These findings highlight a critical regulatory pathway by which ceramide impairs actin polymerization through increased RhoA/Rho kinase signaling and regulates foam cell formation.
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Affiliation(s)
- Rajesh K Singh
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | | | - Inna Grosheva
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Priya Bhardwaj
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Harvey F Chin
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | - Yuquan Xiong
- Vascular Biology Program, Boston Children's Hospital and Department of Surgery, Harvard Medical School, Boston, MA 02115
| | - Timothy Hla
- Vascular Biology Program, Boston Children's Hospital and Department of Surgery, Harvard Medical School, Boston, MA 02115
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7
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Singh RK, Haka AS, Barbosa-Lorenzi VC, Asmal A, Lund F, Xiong Y, Chin HF, Grosheva I, Hla T, Maxfield FR. Abstract 570: Macrophage Catabolism of Aggregated Lipoproteins Using a Novel Extracellular Compartment Regulates Lipid Accumulation During Atherosclerosis. Arterioscler Thromb Vasc Biol 2017. [DOI: 10.1161/atvb.37.suppl_1.570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Despite impressive advances in research, prevention, and treatment, atherosclerotic vascular disease remains the leading cause of death in the developed world. Mechanisms of cholesterol accumulation in the arteries have been studied intensively, but the
in vivo
contributions of different pathways leading to lipid accumulation and foam cell formation are not understood. In the arteries, low-density lipoprotein (LDL) is aggregated and bound to the extracellular matrix. When such aggregated LDL is presented to macrophages, they form a novel acidic, hydrolytic compartment that is topologically extracellular, to which lysosomal enzymes are secreted. Such compartments are observed
in vivo
in murine atherosclerotic plaque macrophages interacting with cholesterol rich deposits. Using state-of-the-art quantitative and high resolution microscopy techniques, characterization of compartment morphology reveals how macrophages use local actin polymerization to drive plasma membrane remodeling at the interface with aggregated LDL. This leads to sequestration of aggregated LDL into topologically convoluted structures that allow acidification, catabolism and internalization of LDL. We find that a TLR4/MyD88/Syk/PI3 kinase/Akt dependent signaling pathway in macrophages regulates the formation of such catabolic compartments. Consistent with this, deficiency of TLR4
in vivo
can protect macrophages from lipid accumulation in murine atherosclerotic plaques. Herein, we provide compelling evidence for a novel form of catabolism that macrophages use to degrade aggregated LDL
in vivo
during atherosclerosis and this process leads to foam cell formation, cell death and promotes disease progression.
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8
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Xiong Y, Lee HJ, Mariko B, Lu YC, Dannenberg AJ, Haka AS, Maxfield FR, Camerer E, Proia RL, Hla T. Sphingosine kinases are not required for inflammatory responses in macrophages. J Biol Chem 2016; 291:11465. [PMID: 27226645 DOI: 10.1074/jbc.a113.483750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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9
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Haka AS, Barbosa-Lorenzi VC, Lee HJ, Falcone DJ, Hudis CA, Dannenberg AJ, Maxfield FR. Exocytosis of macrophage lysosomes leads to digestion of apoptotic adipocytes and foam cell formation. J Lipid Res 2016; 57:980-92. [PMID: 27044658 PMCID: PMC4878183 DOI: 10.1194/jlr.m064089] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Indexed: 12/13/2022] Open
Abstract
Many types of apoptotic cells are phagocytosed and digested by macrophages. Adipocytes can be hundreds of times larger than macrophages, so they are too large to be digested by conventional phagocytic processes. The nature of the interaction between macrophages and apoptotic adipocytes has not been studied in detail. We describe a cellular process, termed exophagy, that is important for macrophage clearance of dead adipocytes and adipose tissue homeostasis. Using mouse models of obesity, human tissue, and a cell culture model, we show that macrophages form hydrolytic extracellular compartments at points of contact with dead adipocytes using local actin polymerization. These compartments are acidic and contain lysosomal enzymes delivered by exocytosis. Uptake and complete degradation of adipocyte fragments, which are released by extracellular hydrolysis, leads to macrophage foam cell formation. Exophagy-mediated foam cell formation is a highly efficient means by which macrophages internalize large amounts of lipid, which may ultimately overwhelm the metabolic capacity of the macrophage. This process provides a mechanism for degradation of objects, such as dead adipocytes, that are too large to be phagocytosed by macrophages.
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Affiliation(s)
- Abigail S Haka
- Departments of Biochemistry, Weill Cornell Medical College, New York, NY 10065
| | | | - Hyuek Jong Lee
- Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Domenick J Falcone
- Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Clifford A Hudis
- Medicine, Weill Cornell Medical College, New York, NY 10065 Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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10
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Haka AS, Sue E, Zhang C, Bhardwaj P, Sterling J, Carpenter C, Leonard M, Manzoor M, Walker J, Aleman JO, Gareau D, Holt PR, Breslow JL, Zhou XK, Giri D, Morrow M, Iyengar N, Barman I, Hudis CA, Dannenberg AJ. Noninvasive Detection of Inflammatory Changes in White Adipose Tissue by Label-Free Raman Spectroscopy. Anal Chem 2016; 88:2140-8. [PMID: 26752499 DOI: 10.1021/acs.analchem.5b03696] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
White adipose tissue inflammation (WATi) has been linked to the pathogenesis of obesity-related diseases, including type 2 diabetes, cardiovascular disease, and cancer. In addition to the obese, a substantial number of normal and overweight individuals harbor WATi, putting them at increased risk for disease. We report the first technique that has the potential to detect WATi noninvasively. Here, we used Raman spectroscopy to detect WATi with excellent accuracy in both murine and human tissues. This is a potentially significant advance over current histopathological techniques for the detection of WATi, which rely on tissue excision and, therefore, are not practical for assessing disease risk in the absence of other identifying factors. Importantly, we show that noninvasive Raman spectroscopy can diagnose WATi in mice. Taken together, these results demonstrate the potential of Raman spectroscopy to provide objective risk assessment for future cardiometabolic complications in both normal weight and overweight/obese individuals.
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Affiliation(s)
- Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College , New York, New York 10065, United States
| | - Erika Sue
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States
| | - Chi Zhang
- Department of Mechanical Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Priya Bhardwaj
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States
| | - Joshua Sterling
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States
| | - Cassidy Carpenter
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States
| | - Madeline Leonard
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States
| | - Maryem Manzoor
- Department of Biochemistry, Weill Cornell Medical College , New York, New York 10065, United States
| | - Jeanne Walker
- Laboratory of Biochemical Genetics and Metabolism, The Rockefeller University , New York, New York 10065, United States
| | - Jose O Aleman
- Laboratory of Biochemical Genetics and Metabolism, The Rockefeller University , New York, New York 10065, United States
| | - Daniel Gareau
- Department of Investigative Dermatology, The Rockefeller University , New York, New York 10065, United States
| | - Peter R Holt
- Laboratory of Biochemical Genetics and Metabolism, The Rockefeller University , New York, New York 10065, United States
| | - Jan L Breslow
- Laboratory of Biochemical Genetics and Metabolism, The Rockefeller University , New York, New York 10065, United States
| | - Xi Kathy Zhou
- Department of Healthcare Policy and Research, Weill Cornell Medical College , New York, New York 10065, United States
| | - Dilip Giri
- Department of Pathology, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - Monica Morrow
- Department of Surgery, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - Neil Iyengar
- Department of Medicine, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - Ishan Barman
- Department of Mechanical Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States.,Department of Oncology, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Clifford A Hudis
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States.,Department of Medicine, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - Andrew J Dannenberg
- Department of Medicine, Weill Cornell Medical College , New York, New York 10065, United States
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11
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Singh RK, Barbosa-Lorenzi VC, Lund FW, Grosheva I, Maxfield FR, Haka AS. Degradation of aggregated LDL occurs in complex extracellular sub-compartments of the lysosomal synapse. J Cell Sci 2016; 129:1072-82. [PMID: 26801085 PMCID: PMC4813320 DOI: 10.1242/jcs.181743] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/19/2016] [Indexed: 01/19/2023] Open
Abstract
Monocyte-derived cells use an extracellular, acidic, lytic compartment (a lysosomal synapse) for initial degradation of large objects or species bound to the extracellular matrix. Akin to osteoclast degradation of bone, extracellular catabolism is used by macrophages to degrade aggregates of low density lipoprotein (LDL) similar to those encountered during atherogenesis. However, unlike osteoclast catabolism, the lysosomal synapse is a highly dynamic and intricate structure. In this study, we use high resolution three dimensional imaging to visualize compartments formed by macrophages to catabolize aggregated LDL. We show that these compartments are topologically complex, have a convoluted structure and contain sub-regions that are acidified. These sub-regions are characterized by a close apposition of the macrophage plasma membrane and aggregates of LDL that are still connected to the extracellular space. Compartment formation is dependent on local actin polymerization. However, once formed, compartments are able to maintain a pH gradient when actin is depolymerized. These observations explain how compartments are able to maintain a proton gradient while remaining outside the boundaries of the plasma membrane.
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Affiliation(s)
- Rajesh K Singh
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | | | - Frederik W Lund
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Inna Grosheva
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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12
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Haka AS, Singh RK, Grosheva I, Hoffner H, Capetillo-Zarate E, Chin HF, Anandasabapathy N, Maxfield FR. Monocyte-Derived Dendritic Cells Upregulate Extracellular Catabolism of Aggregated Low-Density Lipoprotein on Maturation, Leading to Foam Cell Formation. Arterioscler Thromb Vasc Biol 2015; 35:2092-103. [PMID: 26293468 DOI: 10.1161/atvbaha.115.305843] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 08/04/2015] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Although dendritic cells are known to play a role in atherosclerosis, few studies have examined the contribution of the wide variety of dendritic cell subsets. Accordingly, their roles in atherogenesis remain largely unknown. We investigated the ability of different dendritic cell subsets to become foam cells after contact with aggregated low-density lipoprotein (LDL; the predominant form of LDL found in atherosclerotic plaques). APPROACH AND RESULTS We demonstrate that both murine and human monocyte-derived dendritic cells use exophagy to degrade aggregated LDL, leading to foam cell formation, whereas monocyte-independent dendritic cells are unable to clear LDL aggregates by this mechanism. Exophagy is a catabolic process in which objects that cannot be internalized by phagocytosis (because of their size or association with extracellular structures) are initially digested in an extracellular acidic lytic compartment. Surprisingly, we found that monocyte-derived dendritic cells upregulate exophagy on maturation. This contrasts various forms of endocytic internalization in dendritic cells, which decrease on maturation. Finally, we show that our in vitro results are consistent with dendritic cell lipid accumulation in plaques of an ApoE(-/-) mouse model of atherosclerosis. CONCLUSIONS Our results show that monocyte-derived dendritic cells use exophagy to degrade aggregated LDL and become foam cells, whereas monocyte-independent dendritic cells are unable to clear LDL deposits. Furthermore, we find that exophagy is upregulated on dendritic cell maturation. Thus, exophagy-mediated foam cell formation in monocyte-derived dendritic cells could play a significant role in atherogenesis.
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Affiliation(s)
- Abigail S Haka
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Rajesh K Singh
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Inna Grosheva
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Haley Hoffner
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Estibaliz Capetillo-Zarate
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Harvey F Chin
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Niroshana Anandasabapathy
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.)
| | - Frederick R Maxfield
- From the Department of Biochemistry, Weill Cornell Medical College, New York, NY (A.S.H., R.K.S., I.G., H.H., E.C.-Z., H.F.C., F.R.M.); and Department of Dermatology, Harvard Skin Disease Research Center, Bringham and Women's Hospital, Boston, MA (N.A.).
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13
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Singh RK, Haka AS, Grosheva I, Brumfield A, Xiong Y, Hla T, Maxfield FR. Abstract 122: Ceramide Activation of Macrophage RhoA/Rho Kinase/LIM Kinase Signaling Impairs Aggregated LDL Degradation and Foam Cell Formation. Arterioscler Thromb Vasc Biol 2015. [DOI: 10.1161/atvb.35.suppl_1.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction:
One of the initiating events in atherogenesis is the deposition of low-density lipoproteins (LDL) in the arterial wall. This LDL becomes modified, aggregated and retained. Macrophages form a degradative contact (a lysosomal synapse or LS) with the aggregated LDL (agLDL) through local actin polymerization. Degradation of agLDL releases free cholesterol, which is taken up by macrophages and results in foam cell formation. Characterization of proteins regulating actin polymerization that allows LS formation may identify new therapeutic targets to inhibit foam cell formation and halt the progression of atherosclerosis.
Hypothesis:
Small GTPases of the Rho family such as RhoA are key regulators of actin polymerization. Further, many lipids in the micro-environment of the atherosclerotic plaque, such as ceramide, are known to modulate RhoA activity. Therefore we tested the hypothesis that RhoA is important in actin polymerization and foam cell formation in response to macrophage catabolism of agLDL and that this process can be modulated by ceramide.
Methods:
We overexpressed RhoA in RAW264.7 macrophages prior to treatment with agLDL to test the role of RhoA in LS formation and foam cell formation. We used bone marrow derived macrophages (BMM) from Sphingosine Kinase 2 knockout mice (SK2 KO) as a model for macrophages loaded with long chain ceramides and wild-type BMM loaded with C2-ceramide to test the role of ceramide. We also used inhibitors of Rho Kinase ROCK and LIM Kinase to assess their role in LS formation.
Results and Conclusions:
Overexpression of wild-type and constitutive active RhoA in RAW264.7 macrophages significantly impaired actin polymerization and foam cell formation in response to agLDL treatment. Using SK2KO BMM and wild-type BMM loaded with C2- ceramide, we find that macrophages loaded with ceramide display increased levels of activated RhoA. This leads to impaired actin polymerization and foam cell formation which could be rescued by RNAi mediated silencing of RhoA, inhibition of ROCK or inhibition of LIMK. In conclusion, these results suggest that RhoA/ROCK/LIMK signaling negatively regulates agLDL degradation and foam cell formation and that this process can be directly modulated by ceramide through activation of RhoA.
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Affiliation(s)
| | | | - Inna Grosheva
- Biochemistry, Weill Cornell Med College, New York, NY
| | | | - Yuquan Xiong
- Cntr for Vascular Biology, Dept of Pathology and Laboratory Medicine, Weill Cornell Med College, New York, NY
| | - Timothy Hla
- Cntr for Vascular Biology, Dept of Pathology and Laboratory Medicine, Weill Cornell Med College, New York, NY
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Patel JZ, Nevalainen TJ, Savinainen JR, Adams Y, Laitinen T, Runyon RS, Vaara M, Ahenkorah S, Kaczor AA, Navia-Paldanius D, Gynther M, Aaltonen N, Joharapurkar AA, Jain MR, Haka AS, Maxfield FR, Laitinen JT, Parkkari T. Optimization of 1,2,5-thiadiazole carbamates as potent and selective ABHD6 inhibitors. ChemMedChem 2014; 10:253-65. [PMID: 25504894 DOI: 10.1002/cmdc.201402453] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 11/08/2022]
Abstract
At present, inhibitors of α/β-hydrolase domain 6 (ABHD6) are viewed as a promising approach to treat inflammation and metabolic disorders. This article describes the development of 1,2,5-thiadiazole carbamates as ABHD6 inhibitors. Altogether, 34 compounds were synthesized, and their inhibitory activity was tested using lysates of HEK293 cells transiently expressing human ABHD6 (hABHD6). Among the compound series, 4-morpholino-1,2,5-thiadiazol-3-yl cyclooctyl(methyl)carbamate (JZP-430) potently and irreversibly inhibited hABHD6 (IC50 =44 nM) and showed ∼230-fold selectivity over fatty acid amide hydrolase (FAAH) and lysosomal acid lipase (LAL), the main off-targets of related compounds. Additionally, activity-based protein profiling indicated that JZP-430 displays good selectivity among the serine hydrolases of the mouse brain membrane proteome. JZP-430 has been identified as a highly selective, irreversible inhibitor of hABHD6, which may provide a novel approach in the treatment of obesity and type II diabetes.
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Affiliation(s)
- Jayendra Z Patel
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio (Finland).
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15
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Osterberg EC, Laudano MA, Ramasamy R, Sterling J, Robinson BD, Goldstein M, Li PS, Haka AS, Schlegel PN. Identification of spermatogenesis in a rat sertoli-cell only model using Raman spectroscopy: a feasibility study. J Urol 2014; 192:607-12. [PMID: 24518766 DOI: 10.1016/j.juro.2014.01.106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE We determined whether Raman spectroscopy could identify spermatogenesis in a Sertoli-cell only rat model. MATERIALS AND METHODS A partial Sertoli-cell only model was created using a testicular hypothermia-ischemia technique. Bilateral testis biopsy was performed in 4 rats. Raman spectra were acquired with a probe in 1 mm3 samples of testicular tissue. India ink was used to mark the site of spectral acquisition. Comparative histopathology was applied to verify whether Raman spectra were obtained from Sertoli-cell only tubules or seminiferous tubules with spermatogenesis. Principal component analysis and logistic regression were used to develop a mathematical model to evaluate the predictive accuracy of identifying tubules with spermatogenesis vs Sertoli-cell only tubules. RESULTS Raman peak intensity changes were noted at 1,000 and 1,690 cm(-1) for tubules with spermatogenesis and Sertoli-cell only tubules, respectively. When principal components were used to predict whether seminferous tubules were Sertoli-cell only tubules or showed spermatogenesis, sensitivity and specificity were 96% and 100%, respectively. The ROC AUC to predict tubules with spermatogenesis with Raman spectroscopy was 0.98. CONCLUSIONS Raman spectroscopy is capable of identifying seminiferous tubules with spermatogenesis in a Sertoli-cell only ex vivo rat model. Future ex vivo studies of human testicular tissue are necessary to confirm whether these findings can be translated to the clinical setting.
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Affiliation(s)
- E Charles Osterberg
- Department of Urology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Melissa A Laudano
- Department of Urology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Ranjith Ramasamy
- Department of Urology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Joshua Sterling
- Department of Biochemistry, Weill Cornell Medical College, New York, New York
| | - Brian D Robinson
- Department of Pathology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Marc Goldstein
- Department of Urology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Philip S Li
- Department of Urology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York
| | - Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, New York
| | - Peter N Schlegel
- Department of Urology, New York Presbyterian Hospital, Weill Cornell Medical College, New York, New York.
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Xiong Y, Lee HJ, Mariko B, Lu YC, Dannenberg AJ, Haka AS, Maxfield FR, Camerer E, Proia RL, Hla T. Sphingosine kinases are not required for inflammatory responses in macrophages. J Biol Chem 2013; 288:32563-32573. [PMID: 24081141 DOI: 10.1074/jbc.m113.483750] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sphingosine kinases (Sphks), which catalyze the formation of sphingosine 1-phosphate (S1P) from sphingosine, have been implicated as essential intracellular messengers in inflammatory responses. Specifically, intracellular Sphk1-derived S1P was reported to be required for NFκB induction during inflammatory cytokine action. To examine the role of intracellular S1P in the inflammatory response of innate immune cells, we derived murine macrophages that lack both Sphk1 and Sphk2 (MΦ Sphk dKO). Compared with WT counterparts, MΦ Sphk dKO cells showed marked suppression of intracellular S1P levels whereas sphingosine and ceramide levels were strongly up-regulated. Cellular proliferation and apoptosis were similar in MΦ Sphk dKO cells compared with WT counterparts. Treatment of WT and MΦ Sphk dKO with inflammatory mediators TNFα or Escherichia coli LPS resulted in similar NFκB activation and cytokine expression. Furthermore, LPS-induced inflammatory responses, mortality, and thioglycolate-induced macrophage recruitment to the peritoneum were indistinguishable between MΦ Sphk dKO and littermate control mice. Interestingly, autophagic markers were constitutively induced in bone marrow-derived macrophages from Sphk dKO mice. Treatment with exogenous sphingosine further enhanced intracellular sphingolipid levels and autophagosomes. Inhibition of autophagy resulted in caspase-dependent cell death. Together, these data suggest that attenuation of Sphk activity, particularly Sphk2, leads to increased intracellular sphingolipids and autophagy in macrophages.
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Affiliation(s)
- Yuquan Xiong
- From the Center for Vascular Biology, Department of Pathology and Laboratory Medicine
| | - Hyeuk Jong Lee
- From the Center for Vascular Biology, Department of Pathology and Laboratory Medicine,; Department of Medicine
| | - Boubacar Mariko
- INSERM U970, Paris Cardiovascular Research Centre, 75015 Paris, France,; the Université Paris-Descartes, 75015 Paris, France
| | - Yi-Chien Lu
- From the Center for Vascular Biology, Department of Pathology and Laboratory Medicine
| | | | - Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, Cornell University, New York, New York 10065
| | - Frederick R Maxfield
- Department of Biochemistry, Weill Cornell Medical College, Cornell University, New York, New York 10065
| | - Eric Camerer
- INSERM U970, Paris Cardiovascular Research Centre, 75015 Paris, France,; the Université Paris-Descartes, 75015 Paris, France
| | - Richard L Proia
- NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Timothy Hla
- From the Center for Vascular Biology, Department of Pathology and Laboratory Medicine,.
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Haka AS, Grosheva I, Singh RK, Maxfield FR. Plasmin promotes foam cell formation by increasing macrophage catabolism of aggregated low-density lipoprotein. Arterioscler Thromb Vasc Biol 2013; 33:1768-78. [PMID: 23702659 DOI: 10.1161/atvbaha.112.301109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The plasmin/plasminogen system is involved in atherosclerosis. However, the mechanisms by which it stimulates disease are not fully defined. A key event in atherogenesis is the deposition of low-density lipoprotein (LDL) on arterial walls where it is modified, aggregated, and retained. Macrophages are recruited to clear the lipoproteins, and they become foam cells. The goal of this study was to assess the role of plasmin in macrophage uptake of aggregated LDL and foam cell formation. APPROACH AND RESULTS Plasminogen treatment of macrophages catabolizing aggregated LDL significantly accelerated foam cell formation. Macrophage interaction with aggregated LDL increased the surface expression of urokinase-type plasminogen activator receptor and plasminogen activator activity, resulting in increased ability to generate plasmin at the cell surface. The high local level of plasmin cleaves cell-associated aggregated LDL, allowing a portion of the aggregate to become sequestered in a nearly sealed, yet extracellular, acidic compartment. The low pH in the plasmin-induced compartment allows lysosomal enzymes, delivered via lysosome exocytosis, greater activity, resulting in more efficient cholesteryl ester hydrolysis and delivery of a large cholesterol load to the macrophage, thereby promoting foam cell formation. CONCLUSIONS These findings highlight a critical role for plasmin in the catabolism of aggregated LDL by macrophages and provide a new context for considering the atherogenic role of plasmin.
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Affiliation(s)
- Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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18
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Affiliation(s)
- Rajesh K Singh
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkNY
| | - Abigail S Haka
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkNY
| | - Harvey F Chin
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkNY
| | - Inna Grosheva
- Department of BiochemistryWeill Cornell Medical CollegeNew YorkNY
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Angheloiu GO, van de Poll SWE, Georgakoudi I, Motz JT, Haka AS, Podrez E, Fitzmaurice M, Dasari RR, Feld MS, Kramer JR. Intrinsic versus laser-induced fluorescence spectroscopy for coronary atherosclerosis: a generational comparison model for testing diagnostic accuracy. Appl Spectrosc 2012; 66:1403-1410. [PMID: 23231902 DOI: 10.1366/11-06566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Laser-induced fluorescence (LIF) and intrinsic fluorescence spectroscopy (IFS) have been used experimentally for diagnosing coronary atherosclerosis. In this study, we demonstrated the diagnostic superiority of IFS at 342-nm excitation (IFS(342)) versus LIF (LIF(342)) and described a protocol for head-to-head comparison of old (LIF) versus new (IFS) generations of similar diagnostic methods, labeled as "generational comparison model". IFS(342) and LIF(342) were modeled with basis spectra of media, fibrous caps, and superficial foam cells and of their correspondent chemicals (elastin, collagen, and lipoproteins). The average accuracy and receiver operating characteristic area under the curve of IFS(342) in single-, double-, and triple-parameter diagnostic algorithm iterations, geared toward identifying 84 atherosclerotic specimens from a group of 117 coronary segments, was 90% ± 1% and 0.87 ± 0.025, superior to LIF(342) (84% ± 3% and 0.84 ± 0.016; P = 0.0002 and 0.02, respectively) in a generational comparison model.
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Affiliation(s)
- George O Angheloiu
- Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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20
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Haka AS, Potteaux S, Fraser H, Randolph GJ, Maxfield FR. Quantitative analysis of monocyte subpopulations in murine atherosclerotic plaques by multiphoton microscopy. PLoS One 2012; 7:e44823. [PMID: 23024767 PMCID: PMC3443108 DOI: 10.1371/journal.pone.0044823] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 08/07/2012] [Indexed: 12/11/2022] Open
Abstract
The progressive accumulation of monocyte-derived cells in the atherosclerotic plaque is a hallmark of atherosclerosis. However, it is now appreciated that monocytes represent a heterogeneous circulating population of cells that differ in functionality. New approaches are needed to investigate the role of monocyte subpopulations in atherosclerosis since a detailed understanding of their differential mobilization, recruitment, survival and emigration during atherogenesis is of particular importance for development of successful therapeutic strategies. We present a novel methodology for the in vivo examination of monocyte subpopulations in mouse models of atherosclerosis. This approach combines cellular labeling by fluorescent beads with multiphoton microscopy to visualize and monitor monocyte subpopulations in living animals. First, we show that multiphoton microscopy is an accurate and timesaving technique to analyze monocyte subpopulation trafficking and localization in plaques in excised tissues. Next, we demonstrate that multiphoton microscopy can be used to monitor monocyte subpopulation trafficking in atherosclerotic plaques in living animals. This novel methodology should have broad applications and facilitate new insights into the pathogenesis of atherosclerosis and other inflammatory diseases.
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Affiliation(s)
- Abigail S. Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, United States of America
| | - Stephane Potteaux
- Department of Gene and Cell Medicine and the Immunology Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Haley Fraser
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, United States of America
| | - Gwendalyn J. Randolph
- Department of Gene and Cell Medicine and the Immunology Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Frederick R. Maxfield
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, United States of America
- * E-mail:
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Haka AS, Kramer JR, Dasari RR, Fitzmaurice M. Mechanism of ceroid formation in atherosclerotic plaque: in situ studies using a combination of Raman and fluorescence spectroscopy. J Biomed Opt 2011; 16:011011. [PMID: 21280898 PMCID: PMC3041153 DOI: 10.1117/1.3524304] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Accumulation of the lipid-protein complex ceroid is a characteristic of atherosclerotic plaque. The mechanism of ceroid formation has been extensively studied, because the complex is postulated to contribute to plaque irreversibility. Despite intensive research, ceroid deposits are defined through their fluorescence and histochemical staining properties, while their composition remains unknown. Using Raman and fluorescence spectral microscopy, we examine the composition of ceroid in situ in aorta and coronary artery plaque. The synergy of these two types of spectroscopy allows for identification of ceroid via its fluorescence signature and elucidation of its chemical composition through the acquisition of a Raman spectrum. In accordance with in vitro predictions, low density lipoprotein (LDL) appears within the deposits primarily in its peroxidized form. The main forms of modified LDL detected in both coronary artery and aortic plaques are peroxidation products from the Fenton reaction and myeloperoxidase-hypochlorite pathway. These two peroxidation products occur in similar concentrations within the deposits and represent ∼40 and 30% of the total LDL (native and peroxidized) in the aorta and coronary artery deposits, respectively. To our knowledge, this study is the first to successfully employ Raman spectroscopy to unravel a metabolic pathway involved in disease pathogenesis: the formation of ceroid in atherosclerotic plaque.
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Affiliation(s)
- Abigail S Haka
- Massachusetts Institute of Technology, G. R. Harrison Spectroscopy Laboratory, Cambridge, Massachusetts 02139, USA.
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22
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Angheloiu GO, Haka AS, Georgakoudi I, Arendt J, Müller MG, Scepanovic OR, Evanko SP, Wight TN, Mukherjee P, Waldeck DH, Dasari RR, Fitzmaurice M, Kramer JR, Feld MS. Detection of coronary atherosclerotic plaques with superficial proteoglycans and foam cells using real-time intrinsic fluorescence spectroscopy. Atherosclerosis 2010; 215:96-102. [PMID: 21193196 DOI: 10.1016/j.atherosclerosis.2010.11.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 11/05/2010] [Accepted: 11/21/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The protein components of low-density lipoprotein (LDL), oxidized LDL and proteoglycans such as versican contain tryptophan, an amino acid with characteristic fluorescence features at 308 nm excitation wavelength. We hypothesize that intrinsic fluorescence spectroscopy at 308 nm excitation wavelength IFS308, a method suitable for clinical use, can identify coronary artery lesions with superficial foam cells (SFCs) and/or proteoglycans. METHODS We subjected 119 human coronary artery specimens to in vitro fluorescence and reflectance spectroscopy. We used 5 basis spectra to model IFS308, and extracted their contributions to each individual IFS308 spectrum. A diagnostic algorithm using the contributions of Total Tryptophan and fibrous cap to IFS308 was built to identify specimens with SFCs and/or proteoglycans in their top 50 μm. RESULTS We detected SFCs and/or proteoglycans, such as versican or the glycosaminoglycan hyaluronan, in 24 fibrous cap atheromas or pathologic intimal thickening (PIT) lesions. An algorithm using the contributions of Total Tryptophan and fibrous cap to IFS308 was able to identify these segments with 92% sensitivity and 80% specificity. CONCLUSION We were able to establish a set of characteristic LDL, oxidized LDL, versican and hyaluronan fluorescence spectra, ready to be used for real-time diagnosis. The IFS(308) technique detects SFCs and/or proteoglycans in fibrous cap atheromas and PIT lesions. SFCs and proteoglycans are histological markers of vulnerable plaques, and this study is a step further in developing an invasive clinical tool to detect the vulnerable atherosclerotic plaque.
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Affiliation(s)
- George O Angheloiu
- G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Haka AS, Grosheva I, Chiang E, Buxbaum AR, Baird BA, Pierini LM, Maxfield FR. Macrophages Create a Lysosomal Synapse to Digest Aggregated Lipoproteins. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.3151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Haka AS, Grosheva I, Chiang E, Buxbaum AR, Baird BA, Pierini LM, Maxfield FR. Macrophages create an acidic extracellular hydrolytic compartment to digest aggregated lipoproteins. Mol Biol Cell 2009; 20:4932-40. [PMID: 19812252 DOI: 10.1091/mbc.e09-07-0559] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A critical event in atherogenesis is the interaction of macrophages with subendothelial lipoproteins. Although most studies model this interaction by incubating macrophages with monomeric lipoproteins, macrophages in vivo encounter lipoproteins that are aggregated. The physical features of the lipoproteins require distinctive mechanisms for their uptake. We show that macrophages create an extracellular, acidic, hydrolytic compartment to carry out digestion of aggregated low-density lipoproteins. We demonstrate delivery of lysosomal contents to these specialized compartments and their acidification by vacuolar ATPase, enabling aggregate catabolism by lysosomal acid hydrolases. We observe transient sealing of portions of the compartments, allowing formation of an "extracellular" proton gradient. An increase in free cholesterol is observed in aggregates contained in these compartments. Thus, cholesteryl ester hydrolysis can occur extracellularly in a specialized compartment, a lysosomal synapse, during the interaction of macrophages with aggregated low-density lipoprotein. A detailed understanding of these processes is essential for developing strategies to prevent atherosclerosis.
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Affiliation(s)
- Abigail S Haka
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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Haka AS, Volynskaya Z, Gardecki JA, Nazemi J, Shenk R, Wang N, Dasari RR, Fitzmaurice M, Feld MS. Diagnosing breast cancer using Raman spectroscopy: prospective analysis. J Biomed Opt 2009; 14:054023. [PMID: 19895125 PMCID: PMC2774977 DOI: 10.1117/1.3247154] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 07/02/2009] [Accepted: 08/05/2009] [Indexed: 05/18/2023]
Abstract
We present the first prospective test of Raman spectroscopy in diagnosing normal, benign, and malignant human breast tissues. Prospective testing of spectral diagnostic algorithms allows clinicians to accurately assess the diagnostic information contained in, and any bias of, the spectroscopic measurement. In previous work, we developed an accurate, internally validated algorithm for breast cancer diagnosis based on analysis of Raman spectra acquired from fresh-frozen in vitro tissue samples. We currently evaluate the performance of this algorithm prospectively on a large ex vivo clinical data set that closely mimics the in vivo environment. Spectroscopic data were collected from freshly excised surgical specimens, and 129 tissue sites from 21 patients were examined. Prospective application of the algorithm to the clinical data set resulted in a sensitivity of 83%, a specificity of 93%, a positive predictive value of 36%, and a negative predictive value of 99% for distinguishing cancerous from normal and benign tissues. The performance of the algorithm in different patient populations is discussed. Sources of bias in the in vitro calibration and ex vivo prospective data sets, including disease prevalence and disease spectrum, are examined and analytical methods for comparison provided.
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Affiliation(s)
- Abigail S Haka
- Massachusetts Institute of Technology, George R. Harrison Spectroscopy Laboratory, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
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26
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Grosheva I, Haka AS, Qin C, Pierini LM, Maxfield FR. Aggregated LDL in contact with macrophages induces local increases in free cholesterol levels that regulate local actin polymerization. Arterioscler Thromb Vasc Biol 2009; 29:1615-21. [PMID: 19556523 DOI: 10.1161/atvbaha.109.191882] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVE Interaction of macrophages with aggregated matrix-anchored lipoprotein deposits is an important initial step in atherogenesis. Aggregated lipoproteins require different cellular uptake processes than those used for endocytosis of monomeric lipoproteins. In this study, we tested the hypothesis that engagement of aggregated LDL (agLDL) by macrophages could lead to local increases in free cholesterol levels and that these increases in free cholesterol regulate signals that control cellular actin. METHODS AND RESULTS AgLDL resides for prolonged periods in surface-connected compartments. Although agLDL is still extracellular, we demonstrate that an increase in free cholesterol occurs at sites of contact between agLDL and cells because of hydrolysis of agLDL-derived cholesteryl ester. This increase in free cholesterol causes enhanced actin polymerization around the agLDL. Inhibition of cholesteryl ester hydrolysis results in decreased actin polymerization. CONCLUSIONS We describe a novel process that occurs during agLDL-macrophage interactions in which local release of free cholesterol causes local actin polymerization, promoting a pathological positive feedback loop for increased catabolism of agLDL and eventual foam cell formation.
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Affiliation(s)
- Inna Grosheva
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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27
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Volynskaya Z, Haka AS, Bechtel KL, Fitzmaurice M, Shenk R, Wang N, Nazemi J, Dasari RR, Feld MS. Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy. J Biomed Opt 2008; 13:024012. [PMID: 18465975 DOI: 10.1117/1.2909672] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy, we have developed an algorithm that successfully classifies normal breast tissue, fibrocystic change, fibroadenoma, and infiltrating ductal carcinoma in terms of physically meaningful parameters. We acquire 202 spectra from 104 sites in freshly excised breast biopsies from 17 patients within 30 min of surgical excision. The broadband diffuse reflectance and fluorescence spectra are collected via a portable clinical spectrometer and specially designed optical fiber probe. The diffuse reflectance spectra are fit using modified diffusion theory to extract absorption and scattering tissue parameters. Intrinsic fluorescence spectra are extracted from the combined fluorescence and diffuse reflectance spectra and analyzed using multivariate curve resolution. Spectroscopy results are compared to pathology diagnoses, and diagnostic algorithms are developed based on parameters obtained via logistic regression with cross-validation. The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy (total efficiency) of the algorithm are 100, 96, 69, 100, and 91%, respectively. All invasive breast cancer specimens are correctly diagnosed. The combination of diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy yields promising results for discrimination of breast cancer from benign breast lesions and warrants a prospective clinical study.
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Affiliation(s)
- Zoya Volynskaya
- Massachusetts Institute of Technology, Laser Biomedical Research Center, G. R. Harrison Spectroscopy Laboratory, 77 Massachusetts Avenue, 6-218M, Cambridge, Massachusetts 02139, USA.
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Sćepanović OR, Bechtel KL, Haka AS, Shih WC, Koo TW, Berger AJ, Feld MS. Determination of uncertainty in parameters extracted from single spectroscopic measurements. J Biomed Opt 2007; 12:064012. [PMID: 18163828 DOI: 10.1117/1.2815692] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The ability to quantify uncertainty in information extracted from spectroscopic measurements is important in numerous fields. The traditional approach of repetitive measurements may be impractical or impossible in some measurements scenarios, while chi-squared analysis does not provide insight into the sources of uncertainty. As such, a need exists for analytical expressions for estimating uncertainty and, by extension, minimum detectable concentrations or diagnostic parameters, that can be applied to a single noisy measurement. This work builds on established concepts from estimation theory, such as the Cramer-Rao lower bound on estimator covariance, to present an analytical formula for estimating uncertainty expressed as a simple function of measurement noise, signal strength, and spectral overlap. This formalism can be used to evaluate and improve instrument performance, particularly important for rapid-acquisition biomedical spectroscopy systems. We demonstrate the experimental utility of this expression in assessing concentration uncertainties from spectral measurements of aqueous solutions and diagnostic parameter uncertainties extracted from spectral measurements of human artery tissue. The measured uncertainty, calculated from many independent measurements, is found to be in good agreement with the analytical formula applied to a single spectrum. These results are intended to encourage the widespread use of uncertainty analysis in the biomedical optics community.
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Affiliation(s)
- Obrad R Sćepanović
- Massachusetts Institute of Technology, G. R. Harrison Spectroscopy Laboratory, Cambridge, Massachusetts 02139, USA.
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29
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Angheloiu GO, Arendt JT, Müller MG, Haka AS, Georgakoudi I, Motz JT, Scepanovic OR, Kuban BD, Myles J, Miller F, Podrez EA, Fitzmaurice M, Kramer JR, Feld MS. Intrinsic fluorescence and diffuse reflectance spectroscopy identify superficial foam cells in coronary plaques prone to erosion. Arterioscler Thromb Vasc Biol 2006; 26:1594-600. [PMID: 16675721 DOI: 10.1161/01.atv.0000225699.36212.23] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Foam cells perform critical functions in atherosclerosis. We hypothesize that coronary segments with superficial foam cells (SFCs) situated in a region of interest with a depth of 200 mum can be identified using intrinsic fluorescence spectroscopy (IFS) and diffuse reflectance spectroscopy (DRS). This is a key step in our ongoing program to develop a spectroscopic technique for real-time in vivo diagnosis of vulnerable atherosclerotic plaque. METHODS AND RESULTS We subjected 132 human coronary segments to in vitro IFS and DRS. We detected SFCs in 13 thick fibrous cap atheromas and 8 pathologic intimal thickening (PIT) lesions. SFCs colocalized with accumulations of smooth muscle cells and proteoglycans, including hyaluronan (P<0.001). Two spectroscopic parameters were generated from analysis of IFS at 480 nm excitation and DRS. A discriminatory algorithm using these parameters identified specimens with SFC area >40%, 20%, 10%, 5%, 2.5%, and 0% of the region of interest with 98%, 98%, 93%, 94%, 93%, and 90% accuracy, respectively. CONCLUSIONS Our combined IFS and DRS technique accurately detects SFCs in thick fibrous cap atheromas and PIT lesions. Because SFCs are associated with histological markers of plaque erosion, our spectroscopic technique could prove useful in identifying vulnerable plaques.
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Affiliation(s)
- George O Angheloiu
- Spectroscopy Laboratory , Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
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Haka AS, Volynskaya Z, Gardecki JA, Nazemi J, Lyons J, Hicks D, Fitzmaurice M, Dasari RR, Crowe JP, Feld MS. In vivo margin assessment during partial mastectomy breast surgery using raman spectroscopy. Cancer Res 2006; 66:3317-22. [PMID: 16540686 DOI: 10.1158/0008-5472.can-05-2815] [Citation(s) in RCA: 264] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present the first demonstration of in vivo collection of Raman spectra of breast tissue. Raman spectroscopy, which analyzes molecular vibrations, is a promising new technique for the diagnosis of breast cancer. We have collected 31 Raman spectra from nine patients undergoing partial mastectomy procedures to show the feasibility of in vivo Raman spectroscopy for intraoperative margin assessment. The data was fit with an established model, resulting in spectral-based tissue characterization in only 1 second. Application of our previously developed diagnostic algorithm resulted in perfect sensitivity and specificity for distinguishing cancerous from normal and benign tissues in our small data set. Significantly, we have detected a grossly invisible cancer that, upon pathologic review, required the patient to undergo a second surgical procedure. Had Raman spectroscopy been used in a real-time fashion to guide tissue excision during the procedure, the additional reexcision surgery might have been avoided. These preliminary findings suggest that Raman spectroscopy has the potential to lessen the need for reexcision surgeries resulting from positive margins and thereby reduce the recurrence rate of breast cancer following partial mastectomy surgeries.
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Affiliation(s)
- Abigail S Haka
- George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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31
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Motz JT, Fitzmaurice M, Miller A, Gandhi SJ, Haka AS, Galindo LH, Dasari RR, Kramer JR, Feld MS. In vivo Raman spectral pathology of human atherosclerosis and vulnerable plaque. J Biomed Opt 2006; 11:021003. [PMID: 16674178 DOI: 10.1117/1.2190967] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The rupture of vulnerable atherosclerotic plaque accounts for the majority of clinically significant acute cardiovascular events. Because stability of these culprit lesions is directly related to chemical and morphological composition, Raman spectroscopy may be a useful technique for their study. Recent developments in optical fiber probe technology have allowed for the real-time in vivo Raman spectroscopic characterization of human atherosclerotic plaque demonstrated in this work. We spectroscopically examine 74 sites during carotid endarterectomy and femoral artery bypass surgeries. Of these, 34 are surgically biopsied and examined histologically. Excellent signal-to-noise ratio spectra are obtained in only 1 s and fit with an established model, demonstrating accurate tissue characterization. We also report the first evidence that Raman spectroscopy has the potential to identify vulnerable plaque, achieving a sensitivity and specificity of 79 and 85%, respectively. These initial findings indicate that Raman spectroscopy has the potential to be a clinically relevant diagnostic tool for studying cardiovascular disease.
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Affiliation(s)
- Jason T Motz
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts 02114, USA.
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32
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Haka AS, Shafer-Peltier KE, Fitzmaurice M, Crowe J, Dasari RR, Feld MS. Diagnosing breast cancer by using Raman spectroscopy. Proc Natl Acad Sci U S A 2005; 102:12371-6. [PMID: 16116095 PMCID: PMC1194905 DOI: 10.1073/pnas.0501390102] [Citation(s) in RCA: 482] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Indexed: 01/06/2023] Open
Abstract
We employ Raman spectroscopy to diagnose benign and malignant lesions in human breast tissue based on chemical composition. In this study, 130 Raman spectra are acquired from ex vivo samples of human breast tissue (normal, fibrocystic change, fibroadenoma, and infiltrating carcinoma) from 58 patients. Data are fit by using a linear combination model in which nine basis spectra represent the morphologic and chemical features of breast tissue. The resulting fit coefficients provide insight into the chemical/morphological makeup of the tissue and are used to develop diagnostic algorithms. The fit coefficients for fat and collagen are the key parameters in the resulting diagnostic algorithm, which classifies samples according to their specific pathological diagnoses, attaining 94% sensitivity and 96% specificity for distinguishing cancerous tissues from normal and benign tissues. The excellent results demonstrate that Raman spectroscopy has the potential to be applied in vivo to accurately classify breast lesions, thereby reducing the number of excisional breast biopsies that are performed.
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Affiliation(s)
- Abigail S Haka
- G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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33
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Motz JT, Gandhi SJ, Scepanovic OR, Haka AS, Kramer JR, Dasari RR, Feld MS. Real-time Raman system for in vivo disease diagnosis. J Biomed Opt 2005; 10:031113. [PMID: 16229638 DOI: 10.1117/1.1920247] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Raman spectroscopy has been well established as a powerful in vitro method for studying biological tissue and diagnosing disease. The recent development of efficient, high-throughput, low-background optical fiber Raman probes provides, for the first time, the opportunity to obtain real-time performance in the clinic. We present an instrument for in vivo tissue analysis which is capable of collecting and processing Raman spectra in less than 2 s. This is the first demonstration that data acquisition, analysis, and diagnostics can be performed in clinically relevant times. The instrument is designed to work with the new Raman probes and includes custom written LabVIEW and Matlab programs to provide accurate spectral calibration, analysis, and diagnosis along with important safety features related to laser exposure. The real-time capabilities of the system were demonstrated in vivo during femoral bypass and breast lumpectomy surgeries. Such a system will greatly facilitate the adoption of Raman spectroscopy into clinical research and practice.
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Affiliation(s)
- Jason T Motz
- Massachusetts Institute of Technology, George R. Harrison Spectroscopy Laboratory, Cambridge, Massachusetts 02138, USA.
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34
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Abstract
Raman spectral imaging is a powerful tool for determining chemical information in a biological specimen. The challenge is to condense the large amount of spectral information into an easily visualized form with high information content. Researchers have applied a range of techniques, from peak-height ratios to sophisticated models, to produce interpretable Raman images. The purpose of this article is to review some of the more common imaging approaches, in particular principal components analysis, multivariate curve resolution, and Euclidean distance, as well as to present a new technique, morphological modeling. How to best extract meaningful chemical information using each imaging approach will be discussed and examples of images produced with each will be shown.
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Affiliation(s)
- Karen E Shafer-Peltier
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
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35
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Tunnell JW, Haka AS, McGee SA, Mirkovic J, Feld MS. Diagnostic tissue spectroscopy and its applications to gastrointestinal endoscopy. Techniques in Gastrointestinal Endoscopy 2003. [DOI: 10.1053/tgie.2003.50004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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36
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Zhang L, Small GW, Haka AS, Kidder LH, Lewis EN. Classification of Fourier transform infrared microscopic imaging data of human breast cells by cluster analysis and artificial neural networks. Appl Spectrosc 2003; 57:14-22. [PMID: 14610931 DOI: 10.1366/000370203321165151] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cluster analysis and artificial neural networks (ANNs) are applied to the automated assessment of disease state in Fourier transform infrared microscopic imaging measurements of normal and carcinomatous immortalized human breast cell lines. K-means clustering is used to implement an automated algorithm for the assignment of pixels in the image to cell and non-cell categories. Cell pixels are subsequently classified into carcinoma and normal categories through the use of a feed-forward ANN computed with the Broyden-Fletcher-Goldfarb-Shanno training algorithm. Inputs to the ANN consist of principal component scores computed from Fourier filtered absorbance data. A grid search optimization procedure is used to identify the optimal network architecture and filter frequency response. Data from three images corresponding to normal cells, carcinoma cells, and a mixture of normal and carcinoma cells are used to build and test the classification methodology. A successful classifier is developed through this work, although differences in the spectral backgrounds between the three images are observed to complicate the classification problem. The robustness of the final classifier is improved through the use of a rejection threshold procedure to prevent classification of outlying pixels.
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Affiliation(s)
- Lin Zhang
- Ohio University, Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Clippinger Laboratories, Athens, Ohio 45701, USA
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37
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Haka AS, Shafer-Peltier KE, Fitzmaurice M, Crowe J, Dasari RR, Feld MS. Identifying microcalcifications in benign and malignant breast lesions by probing differences in their chemical composition using Raman spectroscopy. Cancer Res 2002; 62:5375-80. [PMID: 12235010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
We have applied Raman spectroscopy to analyze the chemical composition of microcalcifications occurring in benign and malignant lesions in the human breast. Microcalcifications were initially separated into two categories based on their Raman spectrum: type I, calcium oxalate dihydrate, and type II, calcium hydroxyapatite. Type I microcalcifications were diagnosed as benign, whereas type II were subdivided into benign and malignant categories using principal component analysis, a statistical technique. Although type II microcalcifications are primarily composed of calcium hydroxyapatite, they also contain trace amounts of several biological impurities. Using principal component analysis, we were able to highlight subtle chemical differences in type II microcalcifications that correlate with breast disease. On the basis of these results, we believe that type II microcalcifications formed in benign ducts typically contain a larger amount of calcium carbonate and a smaller amount of protein than those formed in malignant ducts. Using this diagnostic strategy, we were able to distinguish microcalcifications occurring in benign and malignant ducts with a sensitivity of 88% and a specificity of 93%. This is a significant improvement over current X-ray mammography techniques, which are unable to reliably differentiate microcalcifications in benign and malignant breast lesions.
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Affiliation(s)
- Abigail S Haka
- G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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