Characterisation of lipofuscin-like lysosomal inclusion bodies from human placenta

FEBS Lett. 2007 Jan 9;581(1):102-8. doi: 10.1016/j.febslet.2006.12.005. Epub 2006 Dec 12.


A structural hallmark of lysosomes is heterogeneity of their contents. We describe a method for isolation of particulate materials from human placental lysosomes. After a methionine methyl ester-induced disruption of lysosomes and two density gradient centrifugations we obtained a homogeneous membrane fraction and another one enriched in particulate inclusions. The latter exhibited a yellow-brown coloration and contained bodies lacking a delimiting membrane, which were characterised by a granular pattern and high electron density. The lipofuscin-like inclusion materials were rich in tripeptidyl peptidase I, beta-glucuronidase, acid ceramidase and apolipoprotein D and contained proteins originating from diverse subcellular localisations. Here we show that human term placenta contains lipofuscin-like lysosomal inclusions, a phenomenon usually associated with senescence in postmitotic cells. These findings imply that a simple pelleting of a lysosomal lysate is not appropriate for the isolation of lysosomal membranes, as the inclusions tend to be sedimented with the membranes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cellular Senescence / physiology
  • Female
  • Humans
  • Inclusion Bodies / chemistry*
  • Inclusion Bodies / enzymology
  • Intracellular Membranes / chemistry
  • Intracellular Membranes / enzymology
  • Lipofuscin / chemistry*
  • Lipofuscin / metabolism
  • Lysosomes / chemistry*
  • Lysosomes / enzymology
  • Placenta / chemistry*
  • Placenta / enzymology
  • Pregnancy
  • Pregnancy Proteins / chemistry*
  • Pregnancy Proteins / metabolism
  • Tripeptidyl-Peptidase 1


  • Lipofuscin
  • Pregnancy Proteins
  • Tripeptidyl-Peptidase 1
  • TPP1 protein, human