Journal article
Regulation of extracellular matrix assembly and structure by hybrid M1/M2 macrophages
Biomaterials, v 269, 120667
Feb 2021
PMID: 33450585
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Aberrant extracellular matrix (ECM) assembly surrounding implanted biomaterials is the hallmark of the foreign body response, in which implants become encapsulated in thick fibrous tissue that prevents their proper function. While macrophages are known regulators of fibroblast behavior, how their phenotype influences ECM assembly and the progression of the foreign body response is poorly understood. In this study, we used in vitro models with physiologically relevant macrophage phenotypes, as well as controlled release of macrophage-modulating cytokines from gelatin hydrogels implanted subcutaneously in vivo to investigate the role of macrophages in ECM assembly. Primary human macrophages were polarized to four distinct phenotypes, which have each been associated with fibrosis, including pro-inflammatory M1, pro-healing M2, and a hybrid M1/M2, generated by exposing macrophages to M1-and M2-promoting stimuli simultaneously. Additionally, macrophages were first polarized to M1 and then to M2 (M1→M2) to generate a phenotype typically observed during normal wound healing. Human dermal fibroblasts that were cultured in macrophage-conditioned media upregulated numerous genes involved in regulation of ECM assembly, especially in M2-conditioned media. Hybrid M1/M2 macrophage-conditioned media caused fibroblasts to produce a matrix with thicker and less aligned fibers, while M2 macrophage-conditioned media caused the formation of a more aligned matrix with thinner fibers. Gelatin methacrylate hydrogels containing interleukin-4 (IL4) and IL13-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were designed to promote the M2 phenotype in a murine subcutaneous in vivo model. NanoString multiplex gene expression analysis of hydrogel explants showed that hydrogels without cytokines caused mostly M1 phenotype markers to be highly expressed at an early time point (3 days), but the release of IL4+IL13 promoted upregulation of M2 markers and genes associated with regulation of ECM assembly, such as Col5a1 and Col6a1. Biochemical analysis and second harmonic generation microscopy showed that the release of IL4+IL13 increased total sulfated glycosaminoglycan content and decreased fibril alignment, which is typically associated with less fibrotic tissue. Together, these results show that hybrid M1/M2 macrophages regulate ECM assembly, and that shifting the balance towards M2 may promote architectural and compositional changes in ECM with enhanced potential for downstream remodeling.
Metrics
Details
- Title
- Regulation of extracellular matrix assembly and structure by hybrid M1/M2 macrophages
- Creators
- Claire E. Witherel - Drexel UniversityKimheak Sao - Department of Biology, College of Arts & Sciences, Drexel University, Philadelphia, PA, USA.Becky K. Brisson - University of PennsylvaniaBiao Han - School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USASusan W. Volk - University of PennsylvaniaRyan J. Petrie - Drexel UniversityLin Han - Drexel UniversityKara L. Spiller - Drexel University
- Publication Details
- Biomaterials, v 269, 120667
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Biology; School of Biomedical Engineering, Science, and Health Systems
- Web of Science ID
- WOS:000617783500002
- Scopus ID
- 2-s2.0-85099126592
- Other Identifier
- 991019168103104721
UN Sustainable Development Goals (SDGs)
This publication has contributed to the advancement of the following goals:
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Engineering, Biomedical
- Materials Science, Biomaterials