Myeloproliferative disease in mice with reduced presenilin gene dosage: effect of gamma-secretase blockage

Biochemistry. 2004 May 11;43(18):5352-9. doi: 10.1021/bi049826u.

Abstract

Mammalian presenilins (PS) consist of two highly homologous proteins, PS1 and PS2. Because of their indispensable activity in the gamma-secretase cleavage of amyloid precursor protein to generate Abeta peptides, inhibition of PS gamma-secretase activity is considered a potential therapy for Abeta blockage and Alzheimer's disease intervention. However, a variety of other substrates are also subject to PS-dependent processing, and it is thus imperative to understand the consequences of PS inactivation in vivo. Here we report a pivotal role of PS in hematopoiesis. Mice heterozygous for PS1 and homozygous for PS2 (PS1(+/)(-)PS2(-)(/)(-)) developed splenomegaly with severe granulocyte infiltration. This was preceded by an overrepresentation of granulocytic cells in the bone marrow and a greatly increased multipotent granulocyte-monocyte progenitor in the spleen. In contrast, hematopoietic stem cells and T- and B-lymphocytes were not affected. Importantly, treatment of wild-type splenocytes with a gamma-secretase inhibitor directly promoted the granulocyte-macrophage colony-forming unit (GM-CFU). These results establish a critical role of PS in myelopoiesis. Our finding that this activity can be directly modulated by its gamma-secretase activity has important safety implications concerning these inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amyloid Precursor Protein Secretases
  • Animals
  • Aspartic Acid Endopeptidases
  • Cell Lineage / genetics
  • Colony-Forming Units Assay
  • Endopeptidases / metabolism*
  • Endopeptidases / physiology
  • Female
  • Gene Dosage*
  • Granulocytes / pathology
  • Hematopoiesis / genetics
  • Leukocyte Count
  • Macrophages / pathology
  • Male
  • Membrane Proteins / deficiency*
  • Membrane Proteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myeloproliferative Disorders / enzymology*
  • Myeloproliferative Disorders / genetics*
  • Myeloproliferative Disorders / pathology
  • Presenilin-1
  • Presenilin-2
  • Protease Inhibitors / pharmacology*

Substances

  • Membrane Proteins
  • Presenilin-1
  • Presenilin-2
  • Protease Inhibitors
  • Amyloid Precursor Protein Secretases
  • Endopeptidases
  • Aspartic Acid Endopeptidases
  • Bace1 protein, mouse