Aging-induced isoDGR-modified fibronectin activates monocytic and endothelial cells to promote atherosclerosis

Jung Eun Park, Gnanasekaran JebaMercy, Kalailingam Pazhanchamy, Xue Guo, So Fong Cam Ngan, Ken Cheng Kang Liou, Soe Ein Si Lynn, Ser Sue Ng, Wei Meng, Su Chi Lim, Melvin Khee Shing Leow, A. Mark Richards, Daniel J. Pennington, Dominique P.V. de Kleijn, Vitaly Sorokin, Hee Hwa Ho, Neil E. McCarthy, Siu Kwan Sze*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)

Abstract

Background and aims: Aging is the primary risk factor for cardiovascular disease (CVD), but the mechanisms underlying age-linked atherosclerosis remain unclear. We previously observed that long-lived vascular matrix proteins can acquire ‘gain-of-function’ isoDGR motifs that might play a role in atherosclerotic pathology. Methods: IsoDGR-specific mAb were generated and used for ELISA-based measurement of motif levels in plasma samples from patients with coronary artery diseases (CAD) and non-CAD controls. Functional consequences of isoDGR accumulation in age-damaged fibronectin were determined by bioassay for capacity to activate monocytes, macrophages, and endothelial cells (signalling activity, pro-inflammatory cytokine expression, and recruitment/adhesion potential). Mice deficient in the isoDGR repair enzyme PCMT1 were used to assess motif distribution and macrophage localisation in vivo. Results: IsoDGR-modified fibronectin and fibrinogen levels in patient plasma were significantly enhanced in CAD and further associated with smoking status. Functional assays demonstrated that isoDGR-modified fibronectin activated both monocytes and macrophages via integrin receptor ‘outside in’ signalling, triggering an ERK:AP-1 cascade and expression of pro-inflammatory cytokines MCP-1 and TNFα to drive additional recruitment of circulating leukocytes. IsoDGR-modified fibronectin also induced endothelial cell expression of integrin β1 to further enhance cellular adhesion and matrix deposition. Analysis of murine aortic tissues confirmed accumulation of isoDGR-modified proteins co-localised with CD68+ macrophages in vivo. Conclusions: Age-damaged fibronectin features isoDGR motifs that increase binding to integrins on the surface of monocytes, macrophages, and endothelial cells. Subsequent activation of ‘outside-in’ signalling elicits a range of potent cytokines and chemokines that drive additional leukocyte recruitment to the developing atherosclerotic matrix.

Original languageEnglish
Pages (from-to)58-68
Number of pages11
JournalAtherosclerosis
Volume324
DOIs
Publication statusPublished - May 2021

Keywords

  • Atherosclerosis
  • Deamidation
  • Fibronectin
  • Integrin
  • isoDGR motif
  • Vascular inflammation

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