Serine protease inhibitor kunitz-type 2 is downregulated in myelodysplastic syndromes and modulates cell-cell adhesion

Stem Cells Dev. 2014 May 15;23(10):1109-20. doi: 10.1089/scd.2013.0441. Epub 2014 Feb 18.

Abstract

Myelodysplastic syndromes (MDS) are clonal disorders involving hematopoietic stem cells (HSC) characterized by ineffective hematopoiesis. In addition to HSC defects, a defective hematopoiesis supporting capacity of mesenchymal stromal cells (MSCs) in the microenvironment niche has been implicated in MDS pathophysiology. The interaction between the dysfunctional MSCs MDS and HSC regulates diverse adhesion-related processes, such as progenitor cell survival, proliferation, differentiation, and self-renewal. As previously reported, a microarray analysis identified serine protease inhibitor kunitz-type 2 (SPINT2), an inhibitor of hepatocyte growth factor (HGF) activation, to be downregulated in MSCs from MDS patients. To define the role of SPINT2 in MDS hematopoietic microenvironment, an analysis of the effect of SPINT2 silencing in MSCs was carried out. We herein reported significantly lower levels of SPINT2 whereas HGF was expressed at higher levels in MSCs from MDS patients compared with healthy controls. SPINT2 underexpression results in an increased expression, production, and secretion of HGF and stromal cell-derived factor 1 (SDF-1) by MSCs. An increased adhesion of normal HSC or malignant cells onto MSCs silenced for SPINT2 was also observed. The altered MSCs adhesion in SPINT2-knockdown cells was correlated with increased CD49b and CD49d expression and with a decrease in CD49e expression. Our results suggest that the SPINT2 underexpression in the MSC from MDS patients is probably involved in the adhesion of progenitors to the bone marrow niche, through an increased HGF and SDF-1 signaling pathway.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cell Adhesion
  • Cell Proliferation
  • Cell Survival
  • Cells, Cultured
  • Chemokine CXCL12 / metabolism
  • Down-Regulation*
  • Female
  • Gene Knockdown Techniques
  • Hematopoietic Stem Cells / metabolism*
  • Hematopoietic Stem Cells / pathology
  • Hepatocyte Growth Factor / metabolism
  • Humans
  • Integrin alpha5 / metabolism
  • Male
  • Membrane Glycoproteins / biosynthesis*
  • Mesenchymal Stem Cells / metabolism*
  • Mesenchymal Stem Cells / pathology
  • Middle Aged
  • Myelodysplastic Syndromes / metabolism*
  • Myelodysplastic Syndromes / pathology

Substances

  • CXCL12 protein, human
  • Chemokine CXCL12
  • HGF protein, human
  • Integrin alpha5
  • Membrane Glycoproteins
  • SPINT2 protein, human
  • Hepatocyte Growth Factor