Open AccessEarly infiltration of p40IL12 + CCR7 + CD11b + cells is critical for fibrosis development
Author(s) -
Braga Tarcio Teodoro,
CorreaCosta Matheus,
Azevedo Hatylas,
Silva Reinaldo Correia,
Cruz Mario Costa,
Almeida Maira Estanislau Soares,
Hiyane Meire Ioshie,
MoreiraFilho Carlos Alberto,
Santos Marinilce Fagundes,
Perez Katia Regina,
Cuccovia Iolanda Midea,
Camara Niels Olsen Saraiva
Publication year - 2016
Publication title -
immunity, inflammation and disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 18
ISSN - 2050-4527
DOI - 10.1002/iid3.114
Subject(s) - infiltration (hvac) , physics , thermodynamics
Macrophages are heterogeneous and thus can be correlated with distinct tissue outcomes after injury. Conflicting data have indicated that the M2‐related phenotype directly triggers fibrosis. Conversely, we hypothesize here that the inflammatory milieu provided by early infiltration of pro‐inflammatory macrophages dictates tissue scarring after injury. Methods and Results We first determined that tissue‐localized macrophages exhibit a pro‐inflammatory phenotype (p40IL12 + CCR7 + CD11b + ) during the early phase of a chronic injury model, in contrast to a pro‐resolving phenotype (Arg1 + IL10 + CD206 + CD11b + ) at a later stage. Then, we evaluated the effects of injecting macrophages differentiated in vitro in the presence of IFNγ + LPS or IL4 + IL13 or non‐differentiated macrophages (hereafter, M0) on promoting inflammation and progression of chronic injury in macrophage‐depleted mice. In addition to enhancing the expression of pro‐inflammatory cytokines, the injection of M (IFNγ + LPS), but not M (IL4 + IL13) or M0, accentuated fibrosis while augmenting levels of anti‐inflammatory molecules, increasing collagen deposition and impairing organ function. We observed a similar profile after injection of sorted CCR7 + CD11b + cells and a more pronounced effect of M (IFNγ + LPS) cells originated from Stat6 −/− mice. The injection of M (IFNγ + LPS) cells was associated with the up‐regulation of inflammation‐ and fibrosis‐related proteins (Thbs1, Mmp7, Mmp8, and Mmp13). Conclusions Our results suggest that pro‐inflammatory macrophages promote microenvironmental changes that may lead to fibrogenesis by inducing an inflammatory milieu that alters a network of extracellular‐related genes, culminating in tissue fibrosis.