The link between stromal cells that control inflammation and tissue damage remains unclear. To this end we have endeavoured to identify stromal cell markers that are upregulated in rheumatoid arthritis and then assess their function. This seminar will discuss one such marker, CD248/Endosialin, and our finding that it acts as a negative regulator of bone formation under resting conditions. We have recently identified a novel, endothelial-specific complex (Multimerin-CLEC14A) for CD248 and demonstrated that this complex is required for sprouting angiogenesis. Given that the vasculature plays a crucial role in controlling osteoblast trafficking and maturation we are now exploring the implications of manipulating this pathway during synovial inflammation and bone damage.