Murine macrophages produce secretory leukocyte protease inhibitor during clearance of apoptotic cells: implications for resolution of the inflammatory response. Academic Article uri icon

Overview

abstract

  • Macrophage-derived secretory leukocyte protease inhibitor (SLPI) can be induced locally as well as systemically in response to microbial products such as LPS and lipotechoic acid. It is not known whether phagocytosis of apoptotic cells, an essential function of macrophages, can regulate expression and secretion of SLPI. In this study, we report that exposure of peritoneal macrophages of BALB/c mice or murine macrophage cell lines RAW264.7 and J774.1 to apoptotic target cells induced an elevation in SLPI secretion. Secreted SLPI retained its antichymotrypsin activity. SLPI expression in thymuses from BALB/c mice that had been injected with anti-CD3 Ab to induce apoptosis of thymocytes was also elevated both at the mRNA and protein levels. Colchicine, a microtubular inhibitor, blocked the internalization of apoptotic cells by macrophages but not SLPI secretion, suggesting that surface recognition of apoptotic cells is sufficient for the induction of SLPI. Exposure of RAW264.7 cells to apoptotic CTLL-2 cells induced both SLPI and TNF-alpha, and addition of IFN-gamma inhibited SLPI but augmented TNF-alpha production. Transfection of either the secreted or a nonsecreted form of SLPI into RAW264.7 cells led to suppression of TNF-alpha production in response to apoptotic cells. Thus, macrophages secrete an increased amount of SLPI when encountering apoptotic cells, which may help to attenuate potential inflammation during clearance of these cells.

publication date

  • August 1, 2003

Research

keywords

  • Apoptosis
  • Macrophages, Peritoneal
  • Phagocytosis
  • Protein Biosynthesis

Identity

Scopus Document Identifier

  • 0042847135

Digital Object Identifier (DOI)

  • 10.4049/jimmunol.171.3.1507

PubMed ID

  • 12874244

Additional Document Info

volume

  • 171

issue

  • 3