Frontline Science: Splenic progenitors aid in maintaining high neutrophil numbers at sites of sterile chronic inflammation

J Leukoc Biol. 2016 Aug;100(2):253-60. doi: 10.1189/jlb.1HI0615-248RR. Epub 2016 Mar 10.

Abstract

Neutrophils are constantly generated from hematopoietic stem and progenitor cells in the bone marrow to maintain high numbers in circulation. A considerable number of neutrophils and their progenitors have been shown to be present in the spleen too; however, their exact role in this organ remains unclear. Herein, we sought to study the function of splenic neutrophils and their progenitors using a mouse model for sterile, peritoneal inflammation. In this microcapsule device implantation model, we show chronic neutrophil presence at implant sites, with recruitment from circulation as the primary mechanism for their prevalence in the peritoneal exudate. Furthermore, we demonstrate that progenitor populations in the spleen play a key role in maintaining elevated neutrophil numbers. Our results provide new insight into the role for splenic neutrophils and their progenitors and establish a model to study neutrophil function during sterile inflammation.

Keywords: biomaterials; devices; granulocyte; hematopoietic stem cells; peritoneal cavity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Bone Marrow / immunology*
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Chronic Disease
  • Cytokines / metabolism
  • Female
  • Inflammation / immunology*
  • Inflammation / pathology
  • Inflammation Mediators / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neutrophil Infiltration / immunology*
  • Neutrophils / cytology
  • Neutrophils / immunology*
  • Neutrophils / metabolism
  • Phagocytosis
  • Prostheses and Implants / adverse effects
  • Spleen / immunology*
  • Spleen / pathology
  • Stem Cells / cytology
  • Stem Cells / immunology*
  • Stem Cells / metabolism

Substances

  • Cytokines
  • Inflammation Mediators