Comparison of gene expression in living and postmortem human brain

Area of Science:

• Neuroscience
• Genomics
• Molecular Biology

Background:

• Studying molecular mechanisms of neuropsychiatric disorders in the human brain presents significant challenges.
• Postmortem human brain samples have been the traditional model, but possess inherent limitations.
• Recent research questioned the utility of postmortem studies by comparing RNA sequencing data from living Parkinson's Disease patients to postmortem tissues.

Approach:

• Re-analyzed RNA sequencing data from a recent study comparing living and postmortem brain tissues.
• Assessed sample quality using standard metrics.
• Performed simulations to evaluate the impact of RNA degradation on differential gene expression analyses.

Key Points:

• Living brain tissue samples in the referenced study were found to be of significantly lower quality than postmortem samples.
• Ignoring RNA degradation in gene expression analyses can lead to substantial artefactual differences.
• The magnitude of these artefactual differences can be comparable to those reported in the original study.

Conclusions:

• The conclusions drawn by the original study regarding the limitations of postmortem brain tissue are not adequately supported.
• While studying gene expression in living brain tissue is valuable, it does not inherently supersede the importance of postmortem analyses.
• Further research is needed to validate findings and establish the comparative utility of living versus postmortem brain tissue studies.