Spontaneous pathology in PS19 tauopathy mice progresses via brain networks

Consistent levels of human tau expression across the lifespan of PS19 mice have been reported in plasma, whole brain, and brain subregions including brainstem and hippocampus.

“Consistent levels of human tau expression across the lifespan of PS19 mice have also been reported in plasma, whole brain (Sun et al., 2020), and brain subregions including brainstem and hippocampus (Ono et al., 2022).”

• cites Sun et al., 2020 sourceDisputed

  The Sun et al. citation is attached to plasma and whole-brain levels, not the brain-subregion claim cited to Ono et al. In Results, the paper reports that plasma human tau tended to increase from 3 to 8 months and stabilized only after 9 months; it also says human tau in total brain kept increasing from 3 to 12 months. Those findings contradict consistent levels across the observed ages. (LLM, conf=0.91)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured
• cites Ono et al., 2022 sourcePartly supported

  The Results (Figure 1f,h; page not specified) report similar human P301S tau expression levels in the hippocampus and brainstem of PS19 mice. Figure 1 describes samples at 4 and 10 months, but the text does not establish consistent expression across the lifespan. The plasma and whole-brain claims are not attributed to Ono et al. in the citing sentence. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

In humans, MRI-based studies using fMRI and tractography cannot precisely map pathology at the cellular level.

“In humans, magnetic resonance imaging- (MRI) based studies using functional MRI (fMRI) and tractography cannot precisely map pathology at the cellular level.”

• cites Seeley et al., 2009 sourcePartly supported

  The Experimental Procedures (Image acquisition and Image preprocessing and analysis; page unavailable) describe millimeter-scale MRI and fMRI measurements, while the Subjects section distinguishes imaging-defined clinical syndromes from underlying histopathology and says predicting neuropathology was not a goal. This supports a limitation on what this study’s imaging maps establish, but the paper does not state the general claim about cellular-level precision or address tractography’s ability to map pathology. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

The general pattern of p-tau accumulation in PS19 mice matched recent reports of brain-wide p-tau accumulation in the P301L tauopathy model.

“The general pattern of p-tau accumulation matched recent reports of brain-wide p-tau accumulation in the P301L tauopathy model (Ramsden et al., 2005; Detrez et al., 2019).”

• cites Ramsden et al., 2005 sourcePartly supported

  The ‘Pathological tau conformation and phosphorylation’ section reports age-dependent accumulation of phosphorylated tau in the cortex and hippocampus of rTg(tauP301L)4510 mice. Figure 1 and the Discussion describe expression as forebrain-restricted, so the paper supports accumulation across those regions but not the claim of brain-wide accumulation. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites Detrez et al., 2019 sourceSupported

The pattern of resistance is consistent with a report of widely variable ages of induction of tau pathology in the PS19 model.

“This pattern is also consistent with a report of widely variable ages of induction of tau pathology in the PS19 model (Woerman et al., 2017).”

• cites Woerman et al., 2017 sourceSupported

Human tau expression was consistently present across brain sections spanning the rostrocaudal extent of the hippocampus at 3, 6, 9 and 12 months of age in PS19 mice.

“Staining for human tau (with HJ8.5 antibody (Yanamandra et al., 2013, Holmes et al., 2014)) showed consistent expression of human tau across brain sections spanning the rostrocaudal extent of the hippocampus at 3, 6, 9 and 12 months of age (Fig. 3).”

• cites Yanamandra et al., 2013 sourceSupported
• cites Holmes et al., 2014 sourceNot checked — no full text of the source

By registering whole brain images of p-tau deposition in PS19 mice into the annotated Allen CCFv3, we identified seven regions which consistently exhibited pathology at 6mo and all later ages.

“By registering whole brain images of p-tau deposition in PS19 mice into the annotated Allen CCFv3, similar to recent studies (Whitesell et al., 2019; Cornblath et al., 2021), we identified seven regions which consistently exhibited pathology at 6mo and all later ages.”

• cites Whitesell et al., 2019 sourceSupported
• cites Cornblath et al., 2021 sourcePartly supported

  The Results section says Cornblath et al. quantified phosphorylated tau pathology in brain regions annotated using the Allen CCF v3. The Methods section describes manually matching annotations to selected coronal sections, not registering whole-brain images into the atlas. The seven regions in PS19 mice are the citing authors’ own finding, not a finding attributed to Cornblath et al. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Spontaneous tau propagation was biased in the retrograde direction.

“Spontaneous tau propagation was biased in the retrograde direction.”

• AssumptionThe authors state this as an assumption: Network diffusion models assume linear diffusion of pathology over the brain connectome composed of white-matter tracts.
• AssumptionThe authors state this as an assumption: Pathology spread from a given brain region to its neighbors is a function of their strength of connections and pathology differentials.

Despite widespread transgene expression, high-resolution whole-brain images revealed p-tau neuropathology that began spontaneously in a small number of distinct brain regions.

“Despite widespread transgene expression, high-resolution whole-brain images revealed p-tau neuropathology that began spontaneously in a small number of distinct brain regions.”

Tauopathy progression correlated with structural connectivity.

“We found that tauopathy progression correlated with structural connectivity, consistent with the prion model.”

The retrograde connectivity model best predicted p-tau levels in most age groups.

“The retrograde connectivity model best predicted p-tau levels in most age groups (Fig. 6C, pink, bottom row).”

The retrograde spread model with the curated set of seven seed regions significantly (p < 0.01) outperformed both single and multiple seed null models in all age groups regardless of cortical mice inclusion.

“Using non-parametric permutation testing, we found the retrograde spread model with the curated set of seven seed regions significantly (p < 0.01) outperformed both single (dark-gray) and multiple seed (light gray) null models in all age groups regardless of cortical mice inclusion.”

6mo animals exhibited low p-tau staining above background, most consistently in brainstem and other caudal regions.

“6mo animals exhibited low p-tau staining above background, most consistently in brainstem and other caudal regions (Fig. 1D, Fig. 2A–D, Supp. Fig. 2A–D, Supp. Fig. 3A–C).”

Cluster C5 contained three 10-12mo brains with a distinct pattern of pronounced staining in isocortex, OLF, HPF, and only moderate staining in P, MY, and CB.

“Finally, three 10–12mo brains clustered together that had a distinct pattern of pathology with pronounced staining in isocortex, OLF, HPF, and only moderate staining in P, MY, and CB (Fig. 5A, “C5”).”

STPT images of VHH-A2-488 immunostained brains demonstrated neuronal p-tau staining across brain regions including entorhinal cortex, piriform cortex and anterior hypothalamic nucleus.

“STPT images of VHH-A2-488 immunostained brains demonstrated neuronal p-tau staining across brain regions including entorhinal cortex (ENT; Fig. 1B), piriform cortex (PIR; Fig. 1C) and anterior hypothalamic nucleus (AHN; Supp. Fig. 1).”

P-tau positive structures in 11-12mo brains largely overlapped those at 9-10mo.

“P-tau positive structures in 11–12mo brains largely overlapped those at 9–10mo.”

Seven consistent seed regions were identified: anterior hypothalamic nucleus (AHN), posterior amygdalar nucleus (PA), paragigantocellular reticular nucleus, lateral part (PGRNl), Barrington's nucleus (B), locus ceruleus (LC), entorhinal area, medial part, dorsal zone (ENTm), and medial vestibular nucleus (MV).

“This curation produced seven consistent seed regions: anterior hypothalamic nucleus (AHN), posterior amygdalar nucleus (PA), paragigantocellular reticular nucleus, lateral part (PGRNl), Barrington’s nucleus (B), locus ceruleus (LC), entorhinal area, medial part, dorsal zone (ENTm), and medial vestibular nucleus (MV) (Fig. 6A).”

There was no correlation between the total number of p-tau positive regions and the network connectivity z-score.

“We also found no correlation between the total number of p-tau positive regions with the network connectivity z-score, indicating that this relationship was not enriched in brains with higher p-tau burden (Fig. 5F).”

The p-tau burden in specific regions was not necessarily higher than in younger animals.

“The p-tau burden in specific regions was not necessarily higher than in the younger animals, possibly owing to degenerative loss of p-tau bearing neurons in the older brains.”

There was no obvious pattern suggesting high p-tau nodes were consistently hyper-connected.

“There was no obvious pattern that suggested high p-tau nodes were consistently hyper-connected.”

Cluster C3 contained four 9-10mo brains with pronounced caudal staining, including P, MY, and CB.

“A third cluster of four 9–10mo brains had pronounced caudal staining, including P, MY, and CB (Fig. 5A, “C3”).”

Core regions with early phospho-tau deposition were identified.

“We identified core regions with early phospho-tau deposition”

An individual brain's p-tau-containing regions were more strongly connected than expected by chance (z-scores >2).

“An individual brain’s p-tau-containing regions were more strongly connected than expected by chance (z-scores >2; Fig. 5E, F).”

The 11-12mo animals often had intense p-tau pathology in many brain structures.

“The 11–12mo animals often had intense p-tau pathology in many brain structures (Fig. 1D, Fig. 2 M–T, Supp. Fig. 2M–T, Supp. Fig. 3J–O).”

Relatively lower correlations for all model predictions were noted in the 9 and 12mo age groups.

“We also noted relatively lower correlations for all model predictions in the 9 and 12mo age groups.”

The 11-12mo brains exhibited pathology in anterior regions such as somatosensory and motor cortices.

“The 11–12mo brains also exhibited pathology in anterior regions such as somatosensory (SS) and motor (MO) cortices”

Despite inter-animal variability at each age, a common set of brain structures with p-tau pathology emerged when comparing 6, 9, and 10mo mice, including pons, medulla, hypothalamus, entorhinal cortex and piriform cortex.

“Despite inter-animal variability at each age, a common set of brain structures with p-tau pathology emerged when comparing 6, 9, and 10mo mice, including the pons (P), medulla (MY), hypothalamus (HY), entorhinal cortex (ENT) and piriform cortex (PIR).”

Cluster C1 contained five 6mo brains and a 9mo brain.

“The cluster with lowest overall p-tau intensity (Fig. 5A, “C1”) contained five 6mo brains, when consistent pathology emerges in the PS19 model (Yoshiyama et al., 2007; Holmes et al., 2014), as well as a 9mo brain.”

• cites Yoshiyama et al., 2007 sourceNot checked — no full text of the source
• cites Holmes et al., 2014 sourceNot checked — no full text of the source

P-tau pathology patterns were highly nonrandom.

“Overall, we found highly nonrandom patterns of p-tau pathology, with C1-C4 appearing to be instances of pathological progression across one distinct subcortical set of regions (“Subcortical”), and C5 appearing to be a late stage of progression across a separate, distinct set of cortical regions (“Cortical”).”

Fewer than 10% of structures in 3-month-old brains were true positives (36/336).

“Since fewer than 10 % of the structures in the 3-month-old brains were true positives (36/336) and most of this signal was extremely sparse”

In tau knockout brains, no neuronal p-tau staining by VHH-A2-488 was observed, confirming a lack of nonspecific staining of non-tau protein by this nanobody.

“In tau knockout brains (Dawson et al., 2001) we observed no neuronal p-tau staining by VHH-A2-488, confirming a lack of nonspecific staining of non-tau protein by this nanobody (Fig. 1B and Supp. Fig. 1).”

• cites Dawson et al., 2001 sourceNot checked — no full text of the source

Two brains (308 and 371) exhibited a lower connection strength among their p-tau-positive structures, which was not explained by their pathological stage or p-tau distribution pattern.

“Notably, two brains (308 and 371) exhibited a lower connection strength among their p-tau-positive structures, which was not explained by their pathological stage or p-tau distribution pattern (Fig. 5E).”

The predictive performance of the retrograde spread model improved when the three Cortical samples were excluded, from r = 0.61 to 0.66 at 10mo and r = 0.45 to 0.66 at 12mo.

“The predictive performance of the retrograde spread model indeed improved, from r = 0.61 to 0.66 (10mo) and r = 0.45 to 0.66 (12mo) (Fig. 6D).”

Consistent patterns of tau pathology were observed at all ages.

“We visually inspected the CCFv3-registered p-tau probability maps and observed consistent patterns of tau pathology at all ages (Fig. 1D, Fig. 2, Supp. Fig. 2, Supp. Fig. 3).”

There was no significant correlation for any connectivity metric (in-strength, out-strength, total strength) with p-tau burden at either 6 or 12 months.

“We plotted the p-tau burden as a function of in-strength, out-strength, and total strength for all mice at the 6 month and 12 month time points and found no significant correlation for any connectivity metric with p-tau burden at either age (Supp. Fig. 5A–C).”

The anterograde connectivity model performed worse than the retrograde model in all but the 9mo age group.

“The anterograde connectivity model performed worse than the retrograde model in all but the 9mo age group (Fig. 6C, green).”

Cluster C2 contained four older (10-11mo) brains and a 9mo brain.

“A second cluster with relatively mild caudal staining contained four older (10–11mo) brains (Fig. 5A, “C2”) as well as a 9mo brain.”

p-tau deposition did not correlate with total tau expression in PS19 mice.

“The results of these experiments indicated that p-tau deposition did not correlate with total tau expression (Figs. 3 and 4).”

• AssumptionRests on an assumption: VHH-A2-488 specifically recognizes p-tau in PS19 brain sections.

Cluster C4 included five 10-12mo brains with intense p-tau staining in caudal regions and increased pathology in midbrain (MB), olfactory areas (OLF), and hippocampal formation (HPF).

“The fourth cluster included five 10–12mo brains with intense p-tau staining in caudal regions and increased pathology in midbrain (MB), olfactory areas (OLF), and the hippocampal formation (HPF)(Fig. 5A, “C4”).”

There were no obvious asymmetries between hemispheres in p-tau staining at any age (Pearson's correlation coefficient 0.9226, p < 1e-12).

“We observed no obvious asymmetries between hemispheres in p-tau staining at any age (Pearson’s correlation coefficient 0.9226, p < 1e-12).”

P-tau signal was generally highest in the pons (P), medulla (MY), and select structures in the cerebellum (CB) and hypothalamus (HY).

“P-tau signal was generally highest in the pons (P), medulla (MY), and select structures in the cerebellum (CB) and hypothalamus (HY).”

Excepting a few caudal structures, brain-wide patterns of neuropathology in the Cortical and Subcortical groups were almost entirely nonoverlapping.

“Remarkably, excepting a few caudal structures, brain-wide patterns of neuropathology in the Cortical and Subcortical groups were almost entirely nonoverlapping (Fig. 5A, B, Movie 1).”

The areas of the brain with tau pathology in any given animal exhibited stronger network inter-connectivity than would be expected from a random set of regions.

“The areas of the brain with tau pathology in any given animal exhibited stronger network inter-connectivity than would be expected from a random set of regions.”

Anatomic proximity, with a few exceptions, had relatively weak predictive power.

“In contrast, anatomic proximity, with a few exceptions, had relatively weak predictive power.”

Connectivity strengths between regions in the retrograde direction best predicted progression of p-tau levels with increasing age.

“We also found that the connectivity strengths between regions in the retrograde direction best predicted progression of p-tau levels with increasing age.”

When the three mice with cortical involvement were not included in the analysis, the predictive power improved for all four models.

“However, when the three mice with cortical involvement were not included in the analysis, the predictive power improved for all four models.”

The retrograde model consistently outperformed the other three models with and without the inclusion of the cortical pattern brains.

“Nevertheless, the retrograde model consistently outperformed the other three models with and without the inclusion of the cortical pattern brains.”

Traditional methods of assessing tau pathology via immunostaining of serial 2D brain sections have supported trans-neuronal propagation of pathological tau in PS19 mice.

“while traditional methods of assessing tau pathology via immunostaining of serial (2-dimensional; 2D) brain sections have supported trans-neuronal propagation of pathological tau in PS19 mice (Wu et al., 2016)”

• cites Wu et al., 2016Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Rodent inoculation methods induce brain trauma.

“these methods induce brain trauma, cannot exclude trafficking of inoculated seeds within a network, and do not reflect the spontaneous development of pathology that occurs in patients.”

The correlation between tauopathy progression and structural connectivity is consistent with the prion model.

“We found that tauopathy progression correlated with structural connectivity, consistent with the prion model.”

Rodent inoculation methods do not reflect the spontaneous development of pathology that occurs in patients.

“these methods induce brain trauma, cannot exclude trafficking of inoculated seeds within a network, and do not reflect the spontaneous development of pathology that occurs in patients.”

Rodent inoculation methods cannot exclude trafficking of inoculated seeds within a network.

“these methods induce brain trauma, cannot exclude trafficking of inoculated seeds within a network, and do not reflect the spontaneous development of pathology that occurs in patients.”

Traditional 2D immunostaining methods pose a barrier to complete, unbiased assessment of pathological progression.

“these methods pose a barrier to complete, unbiased assessment of pathological progression.”

The extensive cortical deposition likely reflected output from a different network pathway than that followed in most brains.

“These results suggested the extensive cortical deposition likely reflected output from a different network pathway than that followed in most brains.”

p-tau accumulated non-randomly.

“This suggested p-tau accumulated non-randomly.”

p-tau accumulation in the PS19 mouse model could not be attributed simply to transgene expression.

“Together, these data strongly suggested that p-tau accumulation in the PS19 mouse model was ordered and progressive in nature, and could not be attributed simply to transgene expression.”

• AssumptionRests on an assumption: VHH-A2-488 specifically recognizes p-tau in PS19 brain sections.

C5 appeared to be a late stage of progression across a separate, distinct set of cortical regions.

“Overall, we found highly nonrandom patterns of p-tau pathology, with C1-C4 appearing to be instances of pathological progression across one distinct subcortical set of regions (“Subcortical”), and C5 appearing to be a late stage of progression across a separate, distinct set of cortical regions (“Cortical”).”

p-tau accumulation in the PS19 mouse model was ordered and progressive in nature.

“Together, these data strongly suggested that p-tau accumulation in the PS19 mouse model was ordered and progressive in nature, and could not be attributed simply to transgene expression.”

• AssumptionRests on an assumption: VHH-A2-488 specifically recognizes p-tau in PS19 brain sections.

C1-C4 appeared to be instances of pathological progression across one distinct subcortical set of regions.

“Overall, we found highly nonrandom patterns of p-tau pathology, with C1-C4 appearing to be instances of pathological progression across one distinct subcortical set of regions (“Subcortical”), and C5 appearing to be a late stage of progression across a separate, distinct set of cortical regions (“Cortical”).”

The network of tau-susceptible structures expanded with age.

“suggesting the network of tau-susceptible structures expanded with age.”

The C1 and C2 cluster composition indicates that some animals were resistant to pathological progression.

“The C1 and C2 cluster composition, where C1 contains a 9mo brain with generally similar p-tau levels to 6mo brains, and C2 contains predominantly older brains with a lower pathological burden indicates that some animals were resistant to pathological progression.”

P-tau spread in PS19 mice was strongly related to the underlying connectome architecture mapped in the Allen Mouse Brain Connectivity Atlas.

“These results further indicated that p-tau spread in PS19 mice was driven specifically from these seven seed regions and was strongly related to the underlying connectome architecture mapped in the Allen Mouse Brain Connectivity Atlas.”

P-tau spread in PS19 mice was driven specifically from the seven seed regions.

“These results further indicated that p-tau spread in PS19 mice was driven specifically from these seven seed regions and was strongly related to the underlying connectome architecture mapped in the Allen Mouse Brain Connectivity Atlas.”

Spread between regions was biased towards the retrograde direction.

“Overall, these data indicated that neuronal p-tau accumulation patterns across age were primarily propagated via the anatomical connectome as opposed to absolute Euclidean proximity between the regions, and that spread between regions was biased towards the retrograde direction.”

The improved fit of the Euclidean model after removal of the 3 "cortical" brains is likely due to the excluded p-tau+ regions being physically further away from the seed regions.

“Importantly, the improved fit of the Euclidean model after removal of the 3 “cortical” brains is likely due to the excluded p-tau+ regions being physically further away from the seed regions.”

In this study, we did not observe enough individual mice at intermediate stages of tau progression to distinguish those that might have been on the "cortical" path from the more prevalent "subcortical" path.

“In this study, we did not observe enough individual mice at intermediate stages of tau progression to distinguish those that might have been on the “cortical” path from the more prevalent “subcortical” path.”

Neuronal p-tau accumulation patterns across age were primarily propagated via the anatomical connectome as opposed to absolute Euclidean proximity between regions.

“Overall, these data indicated that neuronal p-tau accumulation patterns across age were primarily propagated via the anatomical connectome as opposed to absolute Euclidean proximity between the regions, and that spread between regions was biased towards the retrograde direction.”