The role of CX₃CR1⁺ FALC-associated macrophages in health and inflammation

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Presentation Time: 03:15 PM - 04:30 PM
Poster Board Number: B596
Abstract ID: 5189

Presenting Author:
Joseph R Dominguez , PhD Candidate at Univ. of Illinois, Chicago

Abstract:

The omentum is a visceral adipose tissue that contains fat-associated lymphoid clusters (FALC) to aid in peritoneal immunity. These clusters consist of large aggregates of lymphocytes, dendritic cells, macrophages, and innate lymphoid cells that participate in the clearance of pathogens. Tissue-resident macrophages (TRM) are immune cells found in every tissue and can be defined by their origins, consisting of subsets maintained either by embryonic precursors or by bone-marrow progenitors. A recent study found embryonically derived TRM express at least one marker amongst Tim4, LYVE1, FOLR2 while bone marrow derived macrophages maintain CCR2 expression.  Previous publications have shown the existence of LYVE1⁺ macrophages surrounding each cluster, here we study an unexamined subset of FALC-associated macrophages that are imbedded within the lymphoid structures. Using confocal imaging, flow cytometry analysis with reporter/ conditional knock-out mice, we have characterized this TRM subset as CX₃CR1⁺ Tim4^- LYVE1^lo/- and CCR2 dependent. In addition, we examined the interaction between CX₃CR1⁺ macrophages and CCL19⁺ fibroblastic reticular cells by generating CCL19-driven Csf1 depleted mice and found CX₃CR1⁺ macrophages were partially depleted. Lastly, we looked at the role of tissue-resident macrophages in the omentum in early ovarian tumor burden and found omental/peritoneal TRM macrophage depletion by Wt1-driven Csf1 depletion led to increased tumor burden.