Pathomechanisms: homeostatic chemokines in health, tissue regeneration, and progressive diseases

• Homeostatic chemokines support the homing of stem cells and committed progenitor cells.
• They also guide immature lymphocytes from bone marrow to thymus and lymph nodes.
• Their roles in homeostasis contribute to wound healing and tissue regeneration.
• These roles often turn into pathomechanisms, e.g., in chronic inflammation and cancer.

Homeostatic chemokines control stem and progenitor cell migration and activation during vasculogenesis and organ development. They orchestrate hematopoietic stem cell (HSC) homing to their bone marrow niches and direct immature lymphocytes to a series of maturation sites within lymphoid organs. Along these lines, homeostatic chemokines regulate the niches of peripheral committed progenitor cell populations for tissue renewal. These biological functions support neovascularization and wound healing, including the recruitment of endothelial and other progenitor cells from the bone marrow. Here, we summarize the roles of homeostatic chemokines, their signaling receptors, and atypical decoy receptors during homeostasis and tissue regeneration in order to better understand their pathogenic roles in disease, for example, in diabetes complications, cancer, autoimmunity, epithelial hyperplasia, or hypertrophic scarring and fibrosis.