| First Author | Marcatti M | Year | 2022 |
| Journal | Cell Mol Life Sci | Volume | 79 |
| Issue | 4 | Pages | 222 |
| PubMed ID | 35377002 | Mgi Jnum | J:350410 |
| Mgi Id | MGI:7661258 | Doi | 10.1007/s00018-022-04255-9 |
| Citation | Marcatti M, et al. (2022) Abeta/tau oligomer interplay at human synapses supports shifting therapeutic targets for Alzheimer's disease. Cell Mol Life Sci 79(4):222 |
| abstractText | BACKGROUND: Alzheimer's disease (AD) is characterized by progressive cognitive decline due to accumulating synaptic insults by toxic oligomers of amyloid beta (AbetaO) and tau (TauO). There is growing consensus that preventing these oligomers from interacting with synapses might be an effective approach to treat AD. However, recent clinical trial failures suggest low effectiveness of targeting Abeta in late-stage AD. Researchers have redirected their attention toward TauO as the levels of this species increase later in disease pathogenesis. Here we show that AbetaO and TauO differentially target synapses and affect each other's binding dynamics. METHODS: Binding of labeled, pre-formed Abeta and tau oligomers onto synaptosomes isolated from the hippocampus and frontal cortex of mouse and postmortem cognitively intact elderly human brains was evaluated using flow-cytometry and western blot analyses. Binding of labeled, pre-formed Abeta and tau oligomers onto mouse primary neurons was assessed using immunofluorescence assay. The synaptic dysfunction was measured by fluorescence analysis of single-synapse long-term potentiation (FASS-LTP) assay. RESULTS: We demonstrated that higher TauO concentrations effectively outcompete AbetaO and become the prevailing synaptic-associated species. Conversely, high concentrations of AbetaO facilitate synaptic TauO recruitment. Immunofluorescence analyses of mouse primary cortical neurons confirmed differential synaptic binding dynamics of AbetaO and TauO. Moreover, in vivo experiments using old 3xTgAD mice ICV injected with either AbetaO or TauO fully supported these findings. Consistent with these observations, FASS-LTP analyses demonstrated that TauO-induced suppression of chemical LTP was exacerbated by AbetaO. Finally, predigestion with proteinase K abolished the ability of TauO to compete off AbetaO without affecting the ability of high AbetaO levels to increase synaptic TauO recruitment. Thus, unlike AbetaO, TauO effects on synaptosomes are hampered by the absence of protein substrate in the membrane. CONCLUSIONS: These results introduce the concept that TauO become the main synaptotoxic species at late AD, thus supporting the hypothesis that TauO may be the most effective therapeutic target for clinically manifest AD. |
