Perivascular Adipose Tissue Harbors Atheroprotective IgM-Producing B Cells

Frontiers in Physiology

Melissa A. Marshall¹  Sam M. Rosenfeld¹  Prasad Srikakulapu¹  Aditi Upadhye¹  Chantel McSkimming¹  Coleen A. McNamara²  Angela M. Taylor²  M. Beatriz S. Lopes³  Alexandra W. Hickman⁴  Ileana S. Mauldin⁴  Gorav Ailawadi⁴ 

[1] Cardiovascular Research Center, University of VirginiaCharlottesville, VA, United States;Department of Medicine, Division of Cardiovascular Medicine, University of VirginiaCharlottesville, VA, United States;Department of Pathology and Neurological Surgery, University of VirginiaCharlottesville, VA, United States;Department of Surgery, University of VirginiaCharlottesville, VA, United States;

关键词: B cells;    IgM;    atherosclerosis;    inflammation;    perivascular adipose tissue;    fat associated lymphoid clusters;   

DOI  :  10.3389/fphys.2017.00719

来源: DOAJ

【 摘 要 】

Adipose tissue surrounding major arteries (Perivascular adipose tissue or PVAT) has long been thought to exist to provide vessel support and insulation. Emerging evidence suggests that PVAT regulates artery physiology and pathology, such as, promoting atherosclerosis development through local production of inflammatory cytokines. Yet the immune subtypes in PVAT that regulate inflammation are poorly characterized. B cells have emerged as important immune cells in the regulation of visceral adipose tissue inflammation and atherosclerosis. B cell-mediated effects on atherosclerosis are subset-dependent with B-1 cells attenuating and B-2 cells aggravating atherosclerosis. While mechanisms whereby B-2 cells aggravate atherosclerosis are less clear, production of immunoglobulin type M (IgM) antibodies is thought to be a major mechanism whereby B-1 cells limit atherosclerosis development. B-1 cell-derived IgM to oxidation specific epitopes (OSE) on low density lipoproteins (LDL) blocks oxidized LDL-induced inflammatory cytokine production and foam cell formation. However, whether PVAT contains B-1 cells and whether atheroprotective IgM is produced in PVAT is unknown. Results of the present study provide clear evidence that the majority of B cells in and around the aorta are derived from PVAT. Interestingly, a large proportion of these B cells belong to the B-1 subset with the B-1/B-2 ratio being 10-fold higher in PVAT relative to spleen and bone marrow. Moreover, PVAT contains significantly greater numbers of IgM secreting cells than the aorta. ApoE−/− mice with B cell-specific knockout of the gene encoding the helix-loop-helix factor Id3, known to have attenuated diet-induced atherosclerosis, have increased numbers of B-1b cells and increased IgM secreting cells in PVAT relative to littermate controls. Immunostaining of PVAT on human coronary arteries identified fat associated lymphoid clusters (FALCs) harboring high numbers of B cells, and flow cytometry demonstrated the presence of T cells and B cells including B-1 cells. Taken together, these results provide evidence that murine and human PVAT harbor B-1 cells and suggest that local IgM production may serve to provide atheroprotection.

【 授权许可】

Unknown