The postmortem Alzheimer brain is a source of structurally and functionally intact astrocytic messenger RNA

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• The role of astrocytes in Alzheimer's disease (AD) pathogenesis is not fully understood.
• Investigating astrocyte function at a molecular level may offer new insights into dementia.

Purpose of the Study:

• To establish methods for obtaining intact astrocyte-specific messenger RNA (mRNA) from postmortem Alzheimer's disease (AD) brains.
• To assess the presence and integrity of glial fibrillary acidic protein (GFAP) mRNA in AD brains, even after long postmortem intervals.

Main Methods:

• Extraction of poly(A)+ RNA from postmortem control and AD cortices using rapid preparative procedures.
• In vitro protein synthesis using a reticulocyte system to analyze mRNA translation.
• Northern blot hybridization with a human GFAP riboprobe to assess mRNA stability.

Main Results:

• Alzheimer's disease (AD) mRNA yielded a two-fold higher level of glial fibrillary acidic protein (GFAP) compared to controls.
• High levels of GFAP synthesis were observed from AD mRNA, independent of age and postmortem interval up to 24 hours.
• GFAP mRNA remained largely undegraded for at least 10 hours postmortem in AD brain samples.

Conclusions:

• The postmortem Alzheimer's disease (AD) brain is a valuable source of functional and structurally intact astrocyte-specific messenger RNA (mRNA).
• This methodology facilitates further molecular-level investigations into astrocyte function in AD pathogenesis.