arterial macrophage responses in cardiovascular health and
TRANSCRIPT
Clint Robbins Toronto General Research Institute Peter Munk Centre of Excellence in Aortic Disease Departments of Laboratory Medicine and Pathobiology and Immunology, University of Toronto
Ottawa Heart Conference: Inflammation in
Cardiometabolic disease March 31, 2017
No disclosures
Arterial macrophage responses in
cardiovascular health and disease
The normal arterial wall is densely populated by tissue MΦ
Ensan, Li, Besla et al. Nature Immunology 2016
The normal arterial wall is densely populated by tissue MΦ
50μm CD68 DAPI
arterial adventitia
10μm
CX3CL1 CD68 DAPI
MΦ occupy multiple arterial sites.
Spatial distribution of arterial MΦ
Ensan, Li, Besla et al. Nature Immunology 2016
DAPI
BrdU
merge
Mac3
Mac3
BrdU
MΦ dominate inflammation in cardiovascular disease
Robbins, Hilgendorf et al. Nature Medicine 2013
MΦ depletion ameliorates cardiovascular disease
Boring et al. Nature 1998
Are all macrophages created equal?
CCR2
Diversity among tissue macrophages
Diversity among tissue macrophages
Up-regulated Down-regulated
Ensan, Li, Besla et al. Nature Immunology 2016
arterial MΦ alveolar MΦ splenic MΦ microglia
ce
ll n
o.
Lyve-1
96% 12% 3% 1%
Macrophage Origins (beyond environmental influences)
J Exp Med.1968; 128:415-35.
Nature Reviews Immunology 14, 392–404 (2014)
The mouse monocyte compartment
Embryonic MΦ development
Ginhoux et al. Nat Rev Imm 14, 392–404 (2014).
Perdiguero and Geissmann CSH Symposia 2013
Functional differences between bone marrow dependent and independent macrophage networks
Arterial Macrophage
Origins
Embryonic origins of arterial macrophages
Ensan, Li, Besla et al. Nature Immunology 2016
Embryonic origins of macrophages: Lineage Tracing
• pulse-label CX3CR1-expressing progenitor cells in the yolk sac, fetal liver, etc.
• tamoxifen-induced expression of Cre recombinase
under control of CX3CR1 promoter
tamoxifen
X
CX3CR1creER R26Tomato CX3CR1creER: R26Tomato
Adapted from Hofer et al. Annu Rev Immunol. 2016
YS progenitor contribution to arterial MΦ
development
Ensan, Li, Besla et al. Nature Immunology 2016
tamoxifen E8.5
Contribution of YS-derived progenitors to
adult arterial MΦ pool
• YS-derived MΦ persist into adulthood
• what leads to
decline in YS MΦ population shortly after birth?
Ensan, Li, Besla et al. Nature Immunology 2016
Arterial MΦ colonization associates with a brief
post natal period of monocyte recruitment
Ensan, Li, Besla et al. Nature Immunology 2016
tamoxifen E18.5
Monocyte accumulation is associated with
increased arterial expression of chemotactic
factors and adhesion molecules
Ensan, Li, Besla et al. Nature Immunology 2016
Arterial MΦ colonization associates with a brief
post natal period of monocyte recruitment
Ensan, Li, Besla et al. Nature Immunology 2016
What maintains arterial
MΦ abundance in
adulthood?
Ensan, Li, Besla et al. Nature Immunology 2016
Maintenance of arterial MΦ in adulthood occurs
largely independent of circulating monocytes
Maintenance of arterial MΦ in adulthood occurs
largely independent of circulating monocytes
Ensan, Li, Besla et al. Nature Immunology 2016
8 months
parabiosis
C57BL6/J UBC-GFP
Arterial MΦ turnover kinetics
Ensan, Li, Besla et al. Nature Immunology 2016
DOX
H2B-GFP
chase
Tissue MΦ renew through local proliferation
Ensan, Li, Besla et al. Nature Immunology 2016
Arterial MΦ survival
CX3CR1 expression on arterial MΦ persists
into adulthood
Ensan, Li, Besla et al. Nature Immunology 2016
CX3CL1-CX3CR1 interactions maintain arterial
MΦ survival
CX3CL1-CX3CR1 interactions maintain arterial
MΦ survival: The tissue MΦ niche
Ensan, Li, Besla et al. Nature Immunology 2016
CX3CL1-CX3CR1 interactions maintain arterial
MΦ survival: arterial MΦ niche
Arterial MΦ responses
during inflammation
Arterial macrophage diversity during inflammation
Ensan, Li, Besla et al. Nature Immunology 2016
CD45.1 CD45.2
Arterial macrophage diversity during inflammation
Macrophage diversity during inflammation
Ensan, Li, Besla et al. Nature Immunology 2016
Macrophage diversity during inflammation
Ensan, Li, Besla et al. Nature Immunology 2016
Replenishment of arterial MΦ during inflammation
Ensan, Li, Besla et al. Nature Immunology 2016
Tissue resident (Lyve-1+) MΦ Bone marrow-derived
(Lyve-1–) MΦ
Fetal liver Yolk sac
CX3CR1+
precursor
CMP HSC
Bone marrow
Monocytes
Inflammation
Resolution
Flt3+
precursor Inflammation
Development and
homeostasis
Adapted from Klapproth et al. Nature Immunology 2016
• Resident arterial MΦ constitute a distinct population among tissue MΦ.
• Arterial MΦ developmental
pathway is unique - arise embryonically from CX3CR1+ precursors and postnatally from bone marrow-derived monocytes that colonize the tissue immediately after birth.
• Survival of arterial MΦ within
the vascular niche depends on a CX3CR1/CX3CL1 axis.
• In adulthood, proliferation
sustains arterial MΦ in the steady state and after severe depletion following sepsis.
• After infection, arterial MΦ
return to functional homeostasis rapidly.
Conclusions
Collaborators
Myron Cybulsky
Mansoor Husain
Gwendalyn Randolph
Slava Epelman
Cheolho Cheong
Marco Prinz
Ingo Hilgendorf
Filip Swirski
Peter Libby
Anthony Gramolini
Barry Rubin
Acknowledgements
Robbins Lab
Angela Li
Ricky Besla
Sherine Ensan
Eric Shikatani
Shaun Pacheco
Caleb Zavitz
Jake Cosme
Mark Roufaiel
Mahmoud El-Maklizi
Jesse Williams
Peter Wieghofer
Tae Jin Yun
Jun Seong Lee
Funding
•CIHR operating grant MOP133390
•Peter Munk Chair in Aortic Disease
Research