Chronic Innate Immune Signaling in Myelodysplasia

Chronic inflammatory diseases associated with activated innate immune signaling pathways often precede Myelodysplastic Syndromes (MDS), thus a role for chronic innate immune signaling in hematopoietic cells is suspected in the development of MDS. The innate immune system recognizes pathogens and host cellular by-products by pattern recognition receptors (PRR). Among the first PRRs to be identified were the Toll-like receptors (TLRs), which consist of 10 human members. Upon binding to ligand, TLRs recruit intracellular adaptors, kinases, and effector molecules which results in pathway activation. Chronic TLR signaling impairs HSC function, creates an inflammatory environment, and alters normal hematopoiesis, which suggests a causal role in MDS. Despite growing evidence linking dysregulation of innate immune signaling in MDS, how sustained activation of innate immune signaling downstream of various receptor families contributes to MDS remains an open question. This talk will highlight the recent evidence that implicates a cell-intrinsic role of innate immune pathway activation in MDS HSC and environmental inflammatory factors that are involved in the pathogenesis of MDS.