The Alzheimer's amyloid precursor protein is produced by type I astrocytes in primary cultures of rat neuroglia
✍ Scribed by F. Berkenbosch; L. M. Refolo; V. L. Friedrich Jr.; D. Casper; M. Blum; Dr. Nikolaos K. Robakis
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 972 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
The production of P-amyloid precursor protein (PAPP) by primary mixed glial cell cultures from cerebral cortex of 2-3 day postnatal rats was examined by Northern and Western blotting and by immunocytochemistry. A single 3.5 kb PAPP RNA transcript was detected using probes recognizing all forms of PAPP messenger RNA. No signal was detected with a probe specific for the alternately spliced Kunitz protease inhibitor (KPI) region. In Western blot analysis of protein extracts, antisera specific for either the cytoplasmic or extracellular parts of PAPP detected several proteins ranging from 105 to 140 kDa. None of these were recognized by an antiserum specific to the KPI insert of the PAPP. Multicolor immunofluorescence showed PAPP immunoreactivity in type I (GFAP+A2B5-) astrocytes, distributed in a fibrillar pattern like that of glial fibrillary acidic protein (GFAP). No PAPP immunoreactivity was detected in oligodendrocytes (GC +) or in A2B5 + progenitor cells. Moreover, no cultured cells showed immunostaining with an antiserum specific for the KPI sequence of PAPP. We conclude that type I astrocytes in primary culture produce amyloid precursor protein, but that oligodendrocytes and their precursors do not. Moreover, type I astrocytes produce predominently the PAPP subtypes which lacks the KPI sequence.