Temporal lobe in human aging: A quantitative protein profiling study of samples from Chinese Human Brain Bank

• We performed a 4-plex TMT labeled proteomic brain aging study.
• Abundance of a number of proteins in temporal lobe changed during normal brain aging.
• Different pathways activated or impaired at different stages of normal brain aging.
• Bioinformatic analysis delineated a series of degenerative events in normal brain aging.

The temporal lobe is a portion of the cerebral cortex with critical functionality. The age-related protein profile changes in the human temporal lobe have not been previously studied. This 4-plex tandem mass tag labeled proteomic study was performed on samples of temporal lobe from Chinese donors. Tissue samples were assigned to four age groups: Group A (the young, age: 34 ± 13 years); Group B (the elderly, 62 ± 5 years); Group C (the aged, 84 ± 4 years) and Group D (the old, 95 ± 1 years). Pooled samples from the different groups were subjected to proteomics and bioinformatics analysis to identify age-related changes in protein expression and associated pathways. We isolated 5072 proteins, and found that 67 proteins were downregulated and 109 proteins were upregulated in one or more groups during the aging process. Western blotting assays were performed to verify the proteomic results. Bioinformatic analysis identified proteins involved in neuronal degeneration, including proteins involved in neuronal firing, myelin sheath damage, and cell structure stability. We also observed the accumulation of extracellular matrix and lysosomal proteins which imply the occurrence of fibrosis and autophagy. Our results suggest a series of changes across a wide range of proteins in the human temporal lobe that may relate to aging and age-related neurodegenerative disorders.