title: Inflammatory micro-environmental cues of human atherothrombotic arteries confer to vascular smooth muscle cells the capacity to trigger lymphoid neogenesis.
abstract: BACKGROUND
  Experimental atherosclerosis is characterized by the formation of tertiary lymphoid structures (TLOs) within the adventitial layer, which involves the chemokine-expressing aortic smooth muscle cells (SMCs). TLOs have also been described around human atherothrombotic arteries but the mechanisms of their formation remain poorly investigated. Herein, we tested whether human vascular SMCs play the role of chemokine-expressing cells that would trigger the formation of TLOs in atherothrombotic arteries.
  
  
  RESULTS
  We first characterized, by flow cytometry and immunofluorescence analysis, the prevalence and cell composition of TLOs in human abdominal aneurysms of the aorta (AAAs), an evolutive form of atherothrombosis. Chemotaxis experiments revealed that the conditioned medium from AAA tissues recruited significantly more B and T lymphocytes than the conditioned medium from control (N-AAA) tissues. This was associated with an increase in the concentration of CXCL13, CXCL16, CCL19, CCL20, and CCL21 chemokines in the conditioned medium from AAA tissues. Immunofluorescence analysis of AAA cryosections revealed that α-SMA-positive SMCs were the main contributors to the chemokine production. These results were confirmed by RT-qPCR assays where we found that primary vascular SMCs from AAA tissues expressed significantly more chemokines than SMCs from N-AAA. Finally, in vitro experiments demonstrated that the inflammatory cytokines found to be increased in the conditioned medium from AAA were able to trigger the production of chemokines by primary SMCs.
  
  
  CONCLUSIONS
  Together, these results suggest that human vascular SMCs in atherothrombotic arteries, in response to inflammatory signals, are converted into chemokine-expressing cells that trigger the recruitment of immune cells and the formation of aortic TLOs.
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France; Université Denis Diderot, Paris VII, Paris, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Guedj
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France; Université Denis Diderot, Paris VII, Paris, France.
authors.forename: Jamila
authors.initials: J
authors.lastname: Khallou-Laschet
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France; Université Denis Diderot, Paris VII, Paris, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Clement
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Morvan
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Delbosc
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Anh-Thu
authors.initials: AT
authors.lastname: Gaston
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France; Université Denis Diderot, Paris VII, Paris, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: Andreata
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Castier
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Deschildre
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Michel
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Caligiuri
authors.affiliation: Unité 1148, Institut National de la Santé et de la Recherche Médicale (INSERM), Hôpital Xavier Bichat, Paris, France; Université Denis Diderot, Paris VII, Paris, France.
authors.forename: Antonino
authors.initials: A
authors.lastname: Nicoletti
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism*
chemical_list: D017077:Culture Media, Conditioned; D016207:Cytokines