Interleukin-12p35 Deletion Promotes CD4 T-Cell–Dependent Macrophage Differentiation and Enhances Angiotensin II–Induced Cardiac Fibrosis

Abstract

Objective-Interleukin-12 is essential for the differentiation of naïve T cells into interferon-γ-producing T cells, which regulate inflammatory responses. We investigated this process of regulating hypertension-induced cardiac fibrosis. Methods and Results-Mice infused with angiotensin II showed a marked increase in interleukin-12p35 expression in cardiac macrophages. The degree of cardiac fibrosis was significantly enhanced in interleukin-12p35 knockout (p35-KO) mice compared with wild-type (WT) littermates in response to angiotensin II. Fibrotic hearts of p35-KO mice showed increased accumulation of alternatively activated (M2) macrophages and expression of M2 genes such as Arg-1 and Fizz1. Bone marrow-derived macrophages from WT or p35-KO mice did not differ in differentiation in response to angiotensin II treatment; however, in the presence of CD4  T cells, macrophages from p35-KO mice differentiated into M2 macrophages and showed elevated expression of transforming growth factor-β. Moreover, CD4 T-cell-treated p35-KO macrophages could stimulate cardiac fibroblasts to differentiate into α-smooth muscle actin-positive and collagen I-positive myofibroblasts in 3-dimensional nanofiber gels. Neutralizing antibodies against transforming growth factor-β inhibited myofibroblast formation induced by M2 macrophages. Conclusion-Deficiency in interleukin-12p35 regulates angiotensin II-induced cardiac fibrosis by promoting CD4 T-celldependent differentiation of M2 macrophages and production of transforming growth factor-β.

Differences in Cell-Type–Specific Responses to Angiotensin II Explain Cardiac Remodeling Differences in C57BL/6 Mouse Substrains

“…This notion is compatible with the generally held view associating M2 polarized macrophages with tissue remodeling and fibrosis. [31][32][33] Because C57BL/6N mice have gene expression responses that set them apart from either C57BL/6J mice and 2 other inbred mouse strains, it is possible that the divergent response of C57BL/6N mice is a consequence of one of the private mutations that have developed in that strain and is not present in either the C57BL/6J or the other laboratory mouse strains. 16 Of note, 1 major difference between the 2 substrains concerns the inactivation mutation of the Nnt gene, which seemed to have occurred in C57BL/6J mice at The Jackson Laboratory after 1971.…”

Complement 5a Enhances Hepatic Metastases of Colon Cancer via Monocyte Chemoattractant Protein-1-mediated Inflammatory Cell Infiltration

“…Fluorescence data were collected using an EPICS XL Flow Cytometer (Beckman Coulter, Fullerton, CA), and analyzed using CellQuest. A fluorescence-negative control was included to determine the level of nonspecific staining and autofluorescence associated with subsets of cells in each fluorescence channel (30).…”

Interleukin-6/Signal Transducer and Activator of Transcription 3 (STAT3) Pathway Is Essential for Macrophage Infiltration and Myoblast Proliferation during Muscle Regeneration

“…Bone Marrow Cells Adoptive Transfer-Bone marrow cells adoptive transfer was performed as described previously (17). Bone marrow cells of WT or IL-6 Ϫ/Ϫ mice were washed away from femurs and tibias with 25-gauge needle and filtered.…”

“…Cell Culture-Isolation of primary bone marrow-derived macrophages (BMDMs) was performed as described previously (17). WT and IL-6 Ϫ/Ϫ bone marrow cells were obtained from the interface of PBS and Ficoll (HaoYang, TianJin, China) after density centrifugation, then cells were resuspended with growth medium (DMEM high glucose medium supplemented with 10% fetal bovine serum, 1% penicillin-streptomycin) and seeded in the plates for 4 hours.…”