TC1(C8orf4) is upregulated by IL-1β/TNF-α and enhances proliferation of human follicular dendritic cells

Follicular dendritic cells (FDC) play crucial roles in immune regulation. TNF-α has been shown to be essential to the FDC network. However, the molecular regulation of FDC proliferation has not been characterized. Here, we show that TC1(C8orf4), a novel positive regulator of the Wnt/β-catenin pathway in vertebrates, is upregulated by IL-1β and TNF-α in the human FDC-like line HK. TC1 enhances HK cell proliferation, while TC1-knockdown inhibits the proliferation induced by IL-1β, suggesting a role of TC1 as a regulator of FDC proliferation. The regulation by pro-inflammatory cytokines suggests that TC1 might be implicated in linking local inflammation to immune response by stimulating FDC.