Characterisation of lipofuscin-like lysosomal inclusion bodies from human placenta.
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.
Schröder
Bernd
B
Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Strasse 1, 35032 Marburg, Germany. bernd.schroeder@staff.uni-marburg.de
Elsässer
Hans-Peter
HP
Schmidt
Bernhard
B
Hasilik
Andrej
A
D016922:Cellular Senescence / Q000502:physiology; D005260:Female; D006801:Humans; D002479:Inclusion Bodies / Q000737:chemistry* / Q000201:enzymology; D007425:Intracellular Membranes / Q000737:chemistry / Q000201:enzymology; D008062:Lipofuscin / Q000737:chemistry* / Q000378:metabolism; D008247:Lysosomes / Q000737:chemistry* / Q000201:enzymology; D010920:Placenta / Q000737:chemistry* / Q000201:enzymology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000737:chemistry* / Q000378:metabolism; D000091346:Tripeptidyl-Peptidase 1
D008062:Lipofuscin; D011257:Pregnancy Proteins; D000091346:Tripeptidyl-Peptidase 1; C000717267:TPP1 protein, human