Evaluation of cannabinoid type 2 receptor expression and pyridine-based radiotracers in brains from a mouse model of Alzheimer’s disease

Kecheliev, Vasil; Spinelli, Francesco; Herde, Adrienne Müller; Haider, Ahmed; Mu, Linjing; Klohs, Jan; Ametamey, Simon M.; Ni, Ruiqing

doi:10.3389/fnagi.2022.1018610

Cited by 10 publications

(8 citation statements)

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“…We assessed ligand detection of Aβ deposits in brain tissue slices from arcAβ mice using 6E10. arcAβ mice develop Aβ pathology affecting both the brain parenchyma and vasculature from 6 months of age (Kecheliev et al, 2022; Knobloch et al, 2007). Immunofluorescence staining performed on coronal brain tissue sections from arcAβ and nontransgenic mice with ligands (h-FTAA, q-FTAA, and HS-169) co-stained with 6E10 (anti-Aβ 1−16 ) antibody further confirmed the detection of parenchymal Aβ deposits in the cortical regions ( Figs.…”

Section: Resultsmentioning

confidence: 99%

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Efficient characterization of multiple binding sites of small molecule imaging ligands on amyloid-beta, 4-repeat/full-length tau and alpha-synuclein

Sobek

Combes

et al. 2023

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Aim: There is an unmet need for compounds that detect alpha-synuclein (αSyn) and 4-repeat tau, which are critical in many neurodegenerative diseases for diagnostic and therapeutic purposes. Here, we aim to develop an efficient surface plasmon resonance (SPR)-based method to facilitate the characterization of small molecule ligands/compounds to these fibrils. Methods: SPR measurements were conducted to characterize the binding properties of fluorescent ligands/compounds towards recombinant Aβ42, K18 4-repeat/full-length tau and αSyn fibrils. In silico modelling was performed to examine the binding pockets of ligands on αSyn fibrils. Immunofluorescence staining with fluorescence ligands and specific antibodies on postmortem brain tissue slices from patients with Parkinson′s disease and disease mouse models was performed. Results: We optimized the protocol for immobilizing Aβ42, K18 tau, full-length tau and αSyn fibrils in a controlled aggregation state on SPR sensor chips. The results from the analysis of binding kinetics suggested the presence of at least two binding sites for all fibrils, including luminescent conjugated oligothiophenes (HS-169, HS-84, h-FTAA and q-FTAA), pyridine derivative PBB5, nonfluorescent methylene blue and lansoprazole. In silico modelling studies for αSyn (6H6B) showed four binding sites with preference to S4. Immunofluorescence staining validated the detection of pS129-positive αSyn in brain tissue from Parkinson′s disease patients, αSyn PFF-injected mice, 6E10-positive Aβ in arcAβ mice, and AT-8/AT-100-positive in tau pR5 tau mice, respectively. Conclusions: SPR measurements of ligands and small molecules binding to Aβ42, 4R- and full-length tau and αSyn fibrils suggest the existence of multiple binding sites. This approach may provide efficient characterization of compound binding properties towards these fibrils important in neurodegenerative diseases.

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Section: Resultsmentioning

confidence: 99%

Section: Validation Using Immunofluorescence Staining Of Postmortem H...mentioning

confidence: 99%

Efficient characterization of multiple binding sites of small molecule imaging ligands on amyloid-beta, 4-repeat/full-length tau and alpha-synuclein

Sobek

Combes

et al. 2023

Preprint

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“…The sections were permeabilized and blocked in 5% normal donkey or goat serum and 1% Triton-PBS for one hour at room temperature with mild shaking. Free-floating mouse brain tissue sections were incubated with primary antibodies against GFAP, Iba1, AT-8, 6E10, CD68, and P2X7R overnight at 4°C with mild shaking ( Supplemental Table 1 ) (31, 32, 69). The next day, the sections were washed with PBS for 2×20 minutes and incubated with a suitable secondary antibody for 2 hours at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Hippocampal purinergic P2X7 receptor level is increased in Alzheimer’s disease patients, and associated with amyloid and tau pathologies

Maschio,

Wang,

Maheshwari

et al. 2024

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INTRODUCTIONThe purinergic receptor P2X7R, which is expressed on microglia and astrocytes, plays an important role in Alzheimer’s disease (AD). We aimed to characterize the alterations in P2X7R expression in AD patients by APOE ε4 allele, age and sex, as well as its association with amyloid and tau pathology.METHODSP2X7R staining and quantitative analysis of amyloid, tau, astrocytes and microglia were performed on postmortem hippocampal tissues from 35 AD patients; 31 nondemented controls; caudate/putamen tissue from corticobasal degeneration (CBD), progressive supranuclear palsy (PSP) patients; and bran tissue from aged 3×Tg mouse model of AD.RESULTSActivated microglia and reactive astrocytes were observed in the hippocampi of AD patients and exhibited altered morphology with denser cells and pronounced ramifications. Hippocampal P2X7R intensity was greater in the hippocampal subfields of AD patients than in those of nondemented controls and was correlated with amyloid level and Braak stage and was not affected by sex, APOEε4 allele, or age. P2X7R expression increased around Aβ plaques, cerebral amyloid angiopathy, tau inclusions in the hippocampus from AD patients and tau inclusions in the caudate/putamen from CBD and PSP patients.DISCUSSIONWe found an increased hippocampal P2X7R level in AD compared to non-demented control, which correlated with amyloid and tau pathologies. P2X7R is a potential marker for neuroinflammation in AD.

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“…Dissected mouse brains embedded in TissueTek were cut into 10-μm-thick sagittal sections on a cryostat (Cryo-Star HM 560 MV; Microm, Thermo Scientific, USA). The slices were adsorbed on SuperFrost Plus (Menzel, Germany) and stored at −80 °C until further use (30, 58). For [ 18 F]PSS232 autoradiography, slices were thawed on ice and preconditioned with ice-cold buffer (pH 7.4) containing 30 mM HEPES, 1.2 mM MgCl 2 , 110 mM NaCl, 2.5 mM CaCl 2 , 5 mM KCl and 0.1% BSA.…”

Section: Methodsmentioning

confidence: 99%

“…Six 3×Tg mice [B6;129-Psen1tm1MpmTg(APPSwe, tauP301L)1Lfa/Mmjax] were purchased from Jax Laboratory (33,36). Ten arcAβ transgenic mice (human APP695 transgenes harboring Swedish and Arctic (E693G) mutations under the control of the prion protein promoter) (30,56) and eight nontransgenic littermates were used. For the proteomics study, wild-type C57BL6 mice were obtained from Cavins Laboratory Animal Co., Ltd., of Changzhou.…”

Section: Animal Modelsmentioning

confidence: 99%

Hippocampal mGluR5 levels are comparable in Alzheimer’s and control brains, and divergently influenced by amyloid and tau in control brain

Wang,

Savodalli,

Kong

et al. 2024

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Background: Metabotropic glutamate receptor 5 (mGluR5) modulates excitatory glutamatergic synaptic transmission and plays an important role in learning and memory formation and in neurodegeneration and amyloid deposition in Alzheimer′s disease (AD). Conflicting results on the cerebral mGluR5 levels in AD have been reported based on in vivo and postmortem studies. Here, we aimed to assess alterations in hippocampal mGluR5 expression in AD, and the associations between mGluR5 expression and pathologies. Methods: Immunofluorescence staining for mGluR5 was performed on postmortem brain tissue from 34 AD patients and 31 nondemented controls (NCs) and from aged 3xTg and arcAβ model mice of AD. Autoradiography was performed on brain tissue slices from arcAβ mice using mGluR5 tracer [18F]PSS232. Analysis of different cellular source of GRM5 RNA in human and mouse brains was performed. Proteomic profiling and pathway analysis were performed on hippocampal tissue from aged 3xTg mice and wild-type mice. Results: No differences in hippocampal mGluR5 expression or entorhinal cortical GRM5 RNA levels were detected between the AD and NC groups. Hippocampal mGluR5 levels increased with Braak stage and decreased with amyloid level in the NC group. No correlations were detected between the levels of mGluR5 and amyloid, tau, or Iba1/P2X7R in the hippocampus of AD patients and NC cases. Ex vivo autoradiography revealed comparable cerebral levels of [18F]PSS232 in arcAβ mice compared to nontransgenic mice. GO and KEGG pathway enrichment analyses revealed that the Shank3, Grm5 and glutamatergic pathways were upregulated in hippocampal tissue from aged 3xTg mice compared to wild-type mice. Conclusion: This study revealed no difference in hippocampal mGluR5 levels between AD patients and NCs and revealed the divergent influence of amyloid and tau pathologies on hippocampal mGluR5 levels in NCs. Species differences were observed in the GRM5 RNA level as well as at the cellular location.

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Evaluation of cannabinoid type 2 receptor expression and pyridine-based radiotracers in brains from a mouse model of Alzheimer’s disease

Cited by 10 publications

References 67 publications

Efficient characterization of multiple binding sites of small molecule imaging ligands on amyloid-beta, 4-repeat/full-length tau and alpha-synuclein

Efficient characterization of multiple binding sites of small molecule imaging ligands on amyloid-beta, 4-repeat/full-length tau and alpha-synuclein

Hippocampal purinergic P2X7 receptor level is increased in Alzheimer’s disease patients, and associated with amyloid and tau pathologies

Hippocampal mGluR5 levels are comparable in Alzheimer’s and control brains, and divergently influenced by amyloid and tau in control brain

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