Mouse Aorta Smooth Muscle Cells Differentiate Into Lymphoid Tissue Organizer-Like Cells on Combined Tumor Necrosis Factor Receptor-1/Lymphotoxin β-Receptor NF-κB Signaling

Abstract

Objective— Mouse aorta smooth muscle cells (SMC) express tumor necrosis factor receptor superfamily member 1A (TNFR-1) and lymphotoxin β-receptor (LTβR). Circumstantial evidence has linked the SMC LTβR to tertiary lymphoid organogenesis in hyperlipidemic mice. Here, we explored TNFR-1 and LTβR signaling in cultured SMC. Methods and Results— TNFR-1 signaling activated the classical RelA NF-κB pathway, whereas LTβR signaling activated the classical RelA and alternative RelB NF-κB pathways, and both signaling pathways synergized to enhance p100 inhibitor processing to the p52 subunit of NF-κB. Microarrays showed that simultaneous TNFR-1/LTβR activation resulted in elevated mRNA encoding leukocyte homeostatic chemokines CCL2, CCL5, CXCL1, and CX3CL1. Importantly, SMC acquired features of lymphoid tissue organizers, which control tertiary lymphoid organogenesis in autoimmune diseases through hyperinduction of CCL7, CCL9, CXCL13, CCL19, CXCL16, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1. TNFR-1/LTβR cross-talk resulted in augmented secretion of lymphorganogenic chemokine proteins. Supernatants of TNFR-1/LTβR–activated SMC markedly supported migration of splenic T cells, B cells, and macrophages/dendritic cells. Experiments with ltbr −/− SMC indicated that LTβR-RelB activation was obligatory to generate the lymphoid tissue organizer phenotype. Conclusion— SMC may participate in the formation of tertiary lymphoid tissue in atherosclerosis by upregulation of lymphorganogenic chemokines involved in T-lymphocyte, B-lymphocyte, and macrophage/dendritic cell attraction.

Deficiency in Lymphotoxin β Receptor Protects From Atherosclerosis in apoE-Deficient Mice

“…SMCs costimulated with agonistic anti-LTbR and TNF-α also upregulated multiple chemokines, such as Ccl2 and Ccl5, as well as vascular cell adhesion molecule-1 and intracellular adhesion molecule-1. 44 Although not addressed experimentally, the reduction of both local and circulating levels of Ccl5 may contribute to the observed phenotype in apoE 47 , an inhibitor of calcification, and genes involved in the finetuning of inflammatory responses, such as inter α trypsin inhibitor 48 and the lectins Lgals4 and Lgals6. 49 Taken together, these findings support the hypothesis that LTbR on monocytes stimulates monocyte recruitment into atherosclerotic lesions and also promotes plaque inflammation, in part, by activating the Ccl5/Ccr5 pathway, thereby contributing to atheroprogression.…”

From Bystander to Commander

“…Their studies continue with a broad expression analysis revealing a unique transcriptional response in cultured SMC on combined stimulation with TNF␣ and anti-LT␤R. 10 Interestingly, this combination resulted in a synergistically enhanced expression of several chemokines implicated in lymphorganogenesis (eg, CCL7, CCL9, CXCL13, CXCL16, CXCL13, and CCL19). Protein expression and functionality of SMC-derived chemokines were verified by immunoattraction and chemoattraction assays, respectively.…”

Once Upon a Time: The Adaptive Immune Response in Atherosclerosis—a Fairy Tale No More

“…For instance, it seems that vascular smooth muscle cells (VSMCs) could act as LTo cells in aortic TLO formation. Indeed, mouse aortic VSMCs produce the lymphorganogenic chemokines CXCL13 and CCL19 when stimulated in vitro simultaneously through TNFR-1 and LTβR (37). Furthermore, VSMCs located between lesions and TLOs are activated and produce CXCL13 and CCL21 (8).…”