TY - JOUR
T1 - M1 macrophages act as LTβR-independent lymphoid tissue inducer cells during atherosclerosis-related lymphoid neogenesis
AU - Guedj, Kevin
AU - Khallou-Laschet, Jamila
AU - Clement, Marc
AU - Morvan, Marion
AU - Gaston, Anh Thu
AU - Fornasa, Giulia
AU - Dai, Jianping
AU - Gervais-Taurel, Marianne
AU - Eberl, Gerard
AU - Michel, Jean Baptiste
AU - Caligiuri, Giuseppina
AU - Nicoletti, Antonino
PY - 2014/3/1
Y1 - 2014/3/1
N2 - AimsThe goal of this study was to characterize the role of inflammatory macrophages in the induction of the vascular smooth muscle cell (VSMC)-mediated formation of aortic tertiary lymphoid organs (TLOs).Methods and resultsMouse bone marrow-derived M1 macrophages acted as lymphoid tissue inducer cells. Indeed, they expressed high levels of tumour necrosis factor (TNF)- and membrane-bound lymphotoxin (LT)-, two inducing cytokines that triggered expression of the chemokines CCL19, CCL20, and CXCL16, as did M1 supernatant. The blockade of LTβR signalling with LTβR-Ig had no effect, whereas that of TNFR1/2 signalling reduced chemokine expression by VSMCs in both wild-type (WT) and LTβR KO mice, demonstrating that LTβR signalling is dispensable for the M1-inducing effect. This effect was corroborated by the development of TLOs observed in LTβR KO->apolipoprotein E knockout (ApoE KO) aortic segments after orthotopic transplantation. Furthermore, treatment of ApoE KO mice with anti-TNF- antibody decreased the number and incidence of aortic TLOs. Finally, lymphoid nodules composed of T and B cells formed in in vivo-implanted scaffolds seeded with VSMCs previously stimulated ex vivo by M1-conditioned medium.ConclusionsThese results are the first to identify M1 macrophages as inducer cells that trigger the expression of chemokines by VSMCs independently of LTβR signalling. We propose that the dialogue between macrophages and VSMCs-established across the vascular wall-contributes to the formation of aortic TLOs.
AB - AimsThe goal of this study was to characterize the role of inflammatory macrophages in the induction of the vascular smooth muscle cell (VSMC)-mediated formation of aortic tertiary lymphoid organs (TLOs).Methods and resultsMouse bone marrow-derived M1 macrophages acted as lymphoid tissue inducer cells. Indeed, they expressed high levels of tumour necrosis factor (TNF)- and membrane-bound lymphotoxin (LT)-, two inducing cytokines that triggered expression of the chemokines CCL19, CCL20, and CXCL16, as did M1 supernatant. The blockade of LTβR signalling with LTβR-Ig had no effect, whereas that of TNFR1/2 signalling reduced chemokine expression by VSMCs in both wild-type (WT) and LTβR KO mice, demonstrating that LTβR signalling is dispensable for the M1-inducing effect. This effect was corroborated by the development of TLOs observed in LTβR KO->apolipoprotein E knockout (ApoE KO) aortic segments after orthotopic transplantation. Furthermore, treatment of ApoE KO mice with anti-TNF- antibody decreased the number and incidence of aortic TLOs. Finally, lymphoid nodules composed of T and B cells formed in in vivo-implanted scaffolds seeded with VSMCs previously stimulated ex vivo by M1-conditioned medium.ConclusionsThese results are the first to identify M1 macrophages as inducer cells that trigger the expression of chemokines by VSMCs independently of LTβR signalling. We propose that the dialogue between macrophages and VSMCs-established across the vascular wall-contributes to the formation of aortic TLOs.
KW - Atherosclerosis
KW - Chemokine
KW - Lymphocyte
KW - Macrophage
KW - Smooth muscle cell
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U2 - 10.1093/cvr/cvt263
DO - 10.1093/cvr/cvt263
M3 - Article
C2 - 24272771
AN - SCOPUS:84894522129
VL - 101
SP - 434
EP - 443
JO - Cardiovascular Research
JF - Cardiovascular Research
SN - 0008-6363
IS - 3
ER -