Molecular biology in psychiatric research: Alzheimer's disease as a paradigm

Tau-mediated dysregulation of RNA: Evidence for a common molecular mechanism of toxicity in frontotemporal dementia and other tauopathies

Frontotemporal dementias (FTDs) encompass several disorders commonly characterized by progressive frontotemporal lobar degeneration and dementia. Pathologically, TDP-43, FUS, dipeptide repeats, and tau constitute the protein aggregates in FTD, which in turn coincide with heterogeneity in clinical variants. The underlying molecular etiology explaining the formation of each type of protein aggregate remains unclear; however, dysregulated RNA metabolism rises as a common pathogenic factor. Alongside with TDP-43 and FUS, which bind to and regulate RNA dynamics, emerging data suggest that tau may also regulate RNA metabolism and translation. The complex mechanisms that drive translational selectivity in turn regulate the broad clinical presentation of FTDs. Here, we focus on the enigmatic relationship between tau and RNA and review the mechanisms of tau-mediated dysregulation of RNA in tauopathies such as FTD.

Presence of neuronal proteins in serially cultured cells from autopsy human brain

Cells that contain the high (NF-H) and medium (NF-M) molecular weight neurofilaments and neuron-specific enolase (NSE) have been cultured from human brain (Brodmann frontal area 9 and hippocampus) obtained at routine autopsy. Three of these cultures (from a 52-year-old man with vascular dementia, a 75-year-old man with Alzheimer's disease, and an 80-year-old normal woman) have been propagated to passage 12-14 and studied in detail. Cellular morphology was pleomorphic and consistent with a relatively low level of differentiation, by both light microscopic and ultrastructural examination. Immunocytochemical reactivity in a characteristic filamentous pattern was observed with monoclonal antibodies to nonphosphorylated epitopes of NF-H and NF-M as well as with redundant antibody probes specific for NF-H and NF-M. Immunoblotting studies confirmed the presence of NF-H and NF-M. Immunocytochemistry and Immunoblotting also demonstrated the presence of NSE, but not of glial fibrillary acidic protein or other glial markers. Immunocytochemical studies also indicated the presence of proline hydroxylase, an enzyme found in fibroblasts but not neurons. These studies indicate that cells can be cultured from autopsy human brain which are not neurons but nevertheless express molecules used as markers (NF-H, NF-M, and NSE) of adult neurons in vivo and in culture.