1
|
Chambers KL, Myerscough MR, Watson MG, Byrne HM. Blood Lipoproteins Shape the Phenotype and Lipid Content of Early Atherosclerotic Lesion Macrophages: A Dual-Structured Mathematical Model. Bull Math Biol 2024; 86:112. [PMID: 39093509 PMCID: PMC11297092 DOI: 10.1007/s11538-024-01342-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024]
Abstract
Macrophages in atherosclerotic lesions exhibit a spectrum of behaviours or phenotypes. The phenotypic distribution of monocyte-derived macrophages (MDMs), its correlation with MDM lipid content, and relation to blood lipoprotein densities are not well understood. Of particular interest is the balance between low density lipoproteins (LDL) and high density lipoproteins (HDL), which carry bad and good cholesterol respectively. To address these issues, we have developed a mathematical model for early atherosclerosis in which the MDM population is structured by phenotype and lipid content. The model admits a simpler, closed subsystem whose analysis shows how lesion composition becomes more pathological as the blood density of LDL increases relative to the HDL capacity. We use asymptotic analysis to derive a power-law relationship between MDM phenotype and lipid content at steady-state. This relationship enables us to understand why, for example, lipid-laden MDMs have a more inflammatory phenotype than lipid-poor MDMs when blood LDL lipid density greatly exceeds HDL capacity. We show further that the MDM phenotype distribution always attains a local maximum, while the lipid content distribution may be unimodal, adopt a quasi-uniform profile or decrease monotonically. Pathological lesions exhibit a local maximum in both the phenotype and lipid content MDM distributions, with the maximum at an inflammatory phenotype and near the lipid content capacity respectively. These results illustrate how macrophage heterogeneity arises in early atherosclerosis and provide a framework for future model validation through comparison with single-cell RNA sequencing data.
Collapse
Affiliation(s)
- Keith L Chambers
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, Oxfordshire, OX2 6GG, UK.
| | - Mary R Myerscough
- School of Mathematics and Statistics, University of Sydney, Carslaw Building, Eastern Avenue, Camperdown, Sydney, NSW, 2006, Australia
| | - Michael G Watson
- School of Mathematics and Statistics, University of New South Wales, Anita B. Lawrence Centre, University Mall, UNSW, Kensington, Sydney, NSW, 2052, Australia
| | - Helen M Byrne
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, Oxfordshire, OX2 6GG, UK
- Ludwig Institute for Cancer Research, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford, Oxfordshire, OX3 7DQ, UK
| |
Collapse
|
2
|
Yin C, Vrieze AM, Rosoga M, Akingbasote J, Pawlak EN, Jacob RA, Hu J, Sharma N, Dikeakos JD, Barra L, Nagpal AD, Heit B. Efferocytic Defects in Early Atherosclerosis Are Driven by GATA2 Overexpression in Macrophages. Front Immunol 2020; 11:594136. [PMID: 33193444 PMCID: PMC7644460 DOI: 10.3389/fimmu.2020.594136] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/01/2020] [Indexed: 01/01/2023] Open
Abstract
The loss of efferocytosis-the phagocytic clearance of apoptotic cells-is an initiating event in atherosclerotic plaque formation. While the loss of macrophage efferocytosis is a prerequisite for advanced plaque formation, the transcriptional and cellular events in the pre-lesion site that drive these defects are poorly defined. Transcriptomic analysis of macrophages recovered from early-stage human atherosclerotic lesions identified a 50-fold increase in the expression of GATA2, a transcription factor whose expression is normally restricted to the hematopoietic compartment. GATA2 overexpression in vitro recapitulated many of the functional defects reported in patient macrophages, including deficits at multiple stages in the efferocytic process. These findings included defects in the uptake of apoptotic cells, efferosome maturation, and in phagolysosome function. These efferocytic defects were a product of GATA2-driven alterations in the expression of key regulatory proteins, including Src-family kinases, Rab7 and components of both the vacuolar ATPase and NADPH oxidase complexes. In summary, these data identify a mechanism by which efferocytic capacity is lost in the early stages of plaque formation, thus setting the stage for the accumulation of uncleared apoptotic cells that comprise the bulk of atherosclerotic plaques.
Collapse
Affiliation(s)
- Charles Yin
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Angela M Vrieze
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Mara Rosoga
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - James Akingbasote
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Emily N Pawlak
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Rajesh Abraham Jacob
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Jonathan Hu
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Neha Sharma
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Jimmy D Dikeakos
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada
| | - Lillian Barra
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada.,Division of Rheumatology, Department of Medicine, The University of Western Ontario, London, ON, Canada
| | - A Dave Nagpal
- Division of Cardiac Surgery, Department of Surgery, The University of Western Ontario, London, ON, Canada.,Division of Critical Care Medicine, Department of Medicine, The University of Western Ontario, London, ON, Canada
| | - Bryan Heit
- Department of Microbiology and Immunology, and The Center for Human Immunology, The University of Western Ontario, London, ON, Canada.,Robarts Research Institute, London, ON, Canada
| |
Collapse
|