Zhang et al. · Science · 2023

TRIM11 protects against tauopathies and is down-regulated in Alzheimer's disease

Zhang ZY, Harischandra DS, Wang R, Ghaisas S, Zhao JY, McMonagle TP, Zhu G, Lacuarta KD, Song J, Trojanowski JQ, Xu H, Lee VMY, Yang X

Read the paper The product used

The study

What was asked, and what was found

Zhang et al., Science, 2023 screened virtually the whole human tripartite motif protein family for anything that could clear aggregated tau, and TRIM11 came out of that screen as the strongest candidate. It was also markedly lower in Alzheimer's disease brain than in control brain, which made the obvious question whether losing it matters. The paper then shows TRIM11 doing three separate jobs on tau: routing it to the proteasome, acting as a chaperone that stops it misfolding, and acting as a disaggregase that pulls apart fibrils that have already formed.

The loss-of-function arm is where the AUM product was used. AUMsilence sdASOs against Trim11, five separate sequences with a scrambled control and a far red labelled scramble to watch uptake, were added straight into the medium of primary mouse neurons at 10 μM with no transfection reagent, on day 4 and again on day 14. The paper reports that they entered the neurons and lowered TRIM11 to different extents. In cortical neurons from tau transgenic mice seeded with preformed tau fibrils, silencing Trim11 made the pathology worse, raising AT8 and MC1 reactive tau by about 50-90%.

In healthy neurons the same silencing cost them structure. Presynaptic puncta fell by about 40%, postsynaptic puncta by about 30%, and neurofilament light chain by about 40%, while the dendritic control protein MAP2 was unchanged. Across the five sequences, the loss of viability tracked how far each one lowered TRIM11, which is a graded specificity argument rather than a single knockdown. The gain-of-function work that follows used an adeno-associated virus rather than an oligonucleotide, and it goes the other way: more synapses, more neurofilament light chain, resistance to fibril toxicity, and, delivered into the brain, less pathology and better cognition in several tauopathy models.

Key findings

AUMsilence sdASOs against Trim11, added to the medium of primary mouse neurons at 10 μM with no transfection reagent, entered the neurons and lowered TRIM11, and the paper says so in as many words.(Results, TRIM11 protects primary neurons against tau aggregation, fig. S12A and S12B)
Silencing Trim11 in neurons seeded with tau fibrils made the aggregation worse, raising AT8 and MC1 reactive tau by about 50-90%, which is the experiment that shows the protein is needed rather than merely helpful when supplied.(Results, TRIM11 protects primary neurons against tau aggregation, Fig. 5B and 5C)
Silencing Trim11 in healthy neurons cost them synapses and axonal protein: about 40% fewer presynaptic puncta, about 30% fewer postsynaptic puncta and about 40% less neurofilament light chain, while a dendritic control protein was unchanged.(Results, TRIM11 maintains neuronal viability and connectivity, Fig. 5F to 5I)
Five sequences gave five different depths of knockdown, and the loss of neuronal viability tracked the depth, which is a dose-response argument made with sequences rather than with concentration.(Results, TRIM11 maintains neuronal viability and connectivity, Fig. 5M)
The wider paper screened the whole tripartite motif family, found TRIM11 to be the strongest suppressor of tau aggregation and to be markedly lower in Alzheimer's disease brain, and showed it acts as chaperone, disaggregase and route to the proteasome.(Abstract)
The gain-of-function arm used a virus rather than an oligonucleotide, and supplying TRIM11 that way did the opposite of the knockdown: more synaptic puncta, more neurofilament light chain and resistance to fibril toxicity.(Results, TRIM11 maintains neuronal viability and connectivity, Fig. 5N to 5Q)

Product: AUMsilence sdASO
Targets: Trim11 · mouse · mRNATrim11, five separate sequences plus a scrambled control · mouse · mRNA, sequences published in full
Models: primary cortical and hippocampal neurons from wild-type and PS19 human tau P301S transgenic mouse pups · primary cellsPS19 cortical neurons given preformed fibrils of a truncated P301L tau to seed aggregation · primary cells, seeded aggregation modelmultiple mouse models of tauopathy given adeno-associated virus carrying TRIM11 intracranially · in vivo, no oligonucleotide usedpostmortem brain tissue from people with Alzheimer's disease and controls · human tissue, no oligonucleotide used
Delivery: added straight into the culture medium of primary neurons at 10 μM with no transfection reagent, on day 4, repeated on day 14 for the long experiments, with knockdown read 3 days after dosing
Readouts: immunofluorescence for AT8 and MC1 reactive tau, immunoblot, synaptophysin and PSD95 puncta counts, neurofilament light chain and MAP2 staining, neuronal viability assay, fluorescence imaging of labelled oligonucleotide uptake, proximity ligation assay, sedimentation and dot blot for insoluble tau, thioflavin T binding and electron microscopy, behavioural testing in the virus arm
Measured: concentration in the neuron medium: 10 μM final concentration (primary mouse neurons, added on day 4 and again on day 14, knockdown read by immunoblot 3 days after dosing)increase in aggregated tau when Trim11 was silenced: about 50 to 90% (PS19 cortical neurons seeded with preformed fibrils)loss of synaptic and axonal markers on silencing: about 40% fewer synaptophysin puncta, about 30% fewer PSD95 puncta, about 40% less neurofilament light chain, with no change in MAP2 (wild-type mouse cortical neurons)number of targeting sequences and the graded effect across them: five targeting sequences, giving different extents of knockdown, with viability tracking the extent (wild-type mouse cortical neurons)replication behind the neuron panels: n = 6 for the viability panel and n = 3 for the others (Figure 5)the dosing schedule in the seeded aggregation experiment: seeded day 1, oligonucleotide day 4, tau fibrils day 7, oligonucleotide again day 14, read day 21 (primary neurons, preformed fibril transduction)
Figures: Fig. 5 The neuron work: silencing Trim11 worsens seeded tau aggregation and strips synaptic puncta and neurofilament light chain, while the virus arm does the reverse.fig. S12, A and B Uptake of the oligonucleotides into cultured neurons and the different depths of TRIM11 knockdown achieved by each sequence.Fig. 5M Neuronal viability after each of the targeting sequences against the control oligonucleotide.
Citation: Zhang et al. TRIM11 protects against tauopathies and is down-regulated in Alzheimer's disease. Science 2023;381:eadd6696. doi:10.1126/science.add6696

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