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Mechanistic Studies of Antibody-Mediated Clearance of Tau Aggregates Using an ex vivo Brain Slice Model.

Krishnamurthy PK, Deng Y, Sigurdsson EM - Front Psychiatry (2011)

Bottom Line: Thus, clearance of neurofibrillary tangles and/or their precursors may reduce synaptic and neuronal loss associated with AD and other tauopathies.Additionally, tau and FITC-IgG were found together in an enriched lysosome fraction.In summary, antibody-mediated clearance of intracellular tau aggregates appears to occur via the lysosomal pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Neuroscience, New York University School of Medicine New York, NY, USA.

ABSTRACT
Recent studies have shown that immunotherapy clears amyloid beta (Aβ) plaques and reduces Aβ levels in mouse models of Alzheimer's disease (AD), as well as in AD patients. Tangle pathology is also relevant for the neurodegeneration in AD, and our studies have shown that active immunization with an AD related phospho-tau peptide reduces aggregated tau within the brain and slows the progression of tauopathy-induced behavioral impairments. Thus, clearance of neurofibrillary tangles and/or their precursors may reduce synaptic and neuronal loss associated with AD and other tauopathies. So far the mechanisms involved in antibody-mediated clearance of tau pathology are yet to be elucidated. In this study we have used a mouse brain slice model to examine the uptake and localization of FITC labeled anti-tau antibodies. Confocal microscopy analysis showed that the FITC labeled anti-tau antibody co-stained with phosphorylated tau, had a perinuclear appearance and co-localized with markers of the endosomal/lysosomal pathway. Additionally, tau and FITC-IgG were found together in an enriched lysosome fraction. In summary, antibody-mediated clearance of intracellular tau aggregates appears to occur via the lysosomal pathway.

No MeSH data available.


Related in: MedlinePlus

FITC labeled IgG from a high titer mouse co-localizes with phosphorylated and pathological tau within the endosomal/lysosomal system. Confocal microscope images of brain slice sections from JNPL3 transgenic mice and WT (bottom panel) mice. Slices were incubated with FITC–IgG from a high titer Tau 379–408[pSer396, 404] immunized mouse (green) and after sectioning co-stained with an antibody to LAMP2 (red), a marker of late endosomes/lysosomes, and an antibody to Rab5 (red), a marker of early endosomes and the nuclear stain Hoechst 33342. The merged images indicate areas of co-localization between FITC–IgG and endosomes and lysosomes (orange/yellow), mostly in perinuclear areas. Slices were also co-stained with an antibody to MC1 (red), which recognizes a disease related conformational tau epitope and CP13 (red) which recognizes tau pSer202. The merged images indicate areas of co-localization between FITC–IgG and pathological tau (yellow), mostly in perinuclear areas. Minimal staining was observed in the WT mouse. Scale bar = 10 μm.
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Figure 1: FITC labeled IgG from a high titer mouse co-localizes with phosphorylated and pathological tau within the endosomal/lysosomal system. Confocal microscope images of brain slice sections from JNPL3 transgenic mice and WT (bottom panel) mice. Slices were incubated with FITC–IgG from a high titer Tau 379–408[pSer396, 404] immunized mouse (green) and after sectioning co-stained with an antibody to LAMP2 (red), a marker of late endosomes/lysosomes, and an antibody to Rab5 (red), a marker of early endosomes and the nuclear stain Hoechst 33342. The merged images indicate areas of co-localization between FITC–IgG and endosomes and lysosomes (orange/yellow), mostly in perinuclear areas. Slices were also co-stained with an antibody to MC1 (red), which recognizes a disease related conformational tau epitope and CP13 (red) which recognizes tau pSer202. The merged images indicate areas of co-localization between FITC–IgG and pathological tau (yellow), mostly in perinuclear areas. Minimal staining was observed in the WT mouse. Scale bar = 10 μm.

Mentions: Organotypic brain slices were prepared and used to determine the localization of our FITC labeled phos-tau antibody that had been added to the slice culture. Slices were co-stained with antibodies CP13, which recognizes tau phosphorylated at the Ser202 site (Weaver et al., 2000), and MC1, which detects a pathological conformation of tau that is present in AD brain (Jicha et al., 1997), and a Texas Red conjugated secondary antibody. Confocal microscopy images showed extensive but partial co-localization between FITC–IgG and the tau antibodies CP13 and MC1 (Figure 1). Furthermore, we determined that the FITC–IgG was completely associated with cellular markers of lysosomes, LAMP2, and early endosomes, Rab5, with perinuclear vesicles as the main areas of co-staining. In wild type mice, limited non-specific FITC–IgG binding was observed (Figure 1 bottom panel).


Mechanistic Studies of Antibody-Mediated Clearance of Tau Aggregates Using an ex vivo Brain Slice Model.

Krishnamurthy PK, Deng Y, Sigurdsson EM - Front Psychiatry (2011)

FITC labeled IgG from a high titer mouse co-localizes with phosphorylated and pathological tau within the endosomal/lysosomal system. Confocal microscope images of brain slice sections from JNPL3 transgenic mice and WT (bottom panel) mice. Slices were incubated with FITC–IgG from a high titer Tau 379–408[pSer396, 404] immunized mouse (green) and after sectioning co-stained with an antibody to LAMP2 (red), a marker of late endosomes/lysosomes, and an antibody to Rab5 (red), a marker of early endosomes and the nuclear stain Hoechst 33342. The merged images indicate areas of co-localization between FITC–IgG and endosomes and lysosomes (orange/yellow), mostly in perinuclear areas. Slices were also co-stained with an antibody to MC1 (red), which recognizes a disease related conformational tau epitope and CP13 (red) which recognizes tau pSer202. The merged images indicate areas of co-localization between FITC–IgG and pathological tau (yellow), mostly in perinuclear areas. Minimal staining was observed in the WT mouse. Scale bar = 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3198029&req=5

Figure 1: FITC labeled IgG from a high titer mouse co-localizes with phosphorylated and pathological tau within the endosomal/lysosomal system. Confocal microscope images of brain slice sections from JNPL3 transgenic mice and WT (bottom panel) mice. Slices were incubated with FITC–IgG from a high titer Tau 379–408[pSer396, 404] immunized mouse (green) and after sectioning co-stained with an antibody to LAMP2 (red), a marker of late endosomes/lysosomes, and an antibody to Rab5 (red), a marker of early endosomes and the nuclear stain Hoechst 33342. The merged images indicate areas of co-localization between FITC–IgG and endosomes and lysosomes (orange/yellow), mostly in perinuclear areas. Slices were also co-stained with an antibody to MC1 (red), which recognizes a disease related conformational tau epitope and CP13 (red) which recognizes tau pSer202. The merged images indicate areas of co-localization between FITC–IgG and pathological tau (yellow), mostly in perinuclear areas. Minimal staining was observed in the WT mouse. Scale bar = 10 μm.
Mentions: Organotypic brain slices were prepared and used to determine the localization of our FITC labeled phos-tau antibody that had been added to the slice culture. Slices were co-stained with antibodies CP13, which recognizes tau phosphorylated at the Ser202 site (Weaver et al., 2000), and MC1, which detects a pathological conformation of tau that is present in AD brain (Jicha et al., 1997), and a Texas Red conjugated secondary antibody. Confocal microscopy images showed extensive but partial co-localization between FITC–IgG and the tau antibodies CP13 and MC1 (Figure 1). Furthermore, we determined that the FITC–IgG was completely associated with cellular markers of lysosomes, LAMP2, and early endosomes, Rab5, with perinuclear vesicles as the main areas of co-staining. In wild type mice, limited non-specific FITC–IgG binding was observed (Figure 1 bottom panel).

Bottom Line: Thus, clearance of neurofibrillary tangles and/or their precursors may reduce synaptic and neuronal loss associated with AD and other tauopathies.Additionally, tau and FITC-IgG were found together in an enriched lysosome fraction.In summary, antibody-mediated clearance of intracellular tau aggregates appears to occur via the lysosomal pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Neuroscience, New York University School of Medicine New York, NY, USA.

ABSTRACT
Recent studies have shown that immunotherapy clears amyloid beta (Aβ) plaques and reduces Aβ levels in mouse models of Alzheimer's disease (AD), as well as in AD patients. Tangle pathology is also relevant for the neurodegeneration in AD, and our studies have shown that active immunization with an AD related phospho-tau peptide reduces aggregated tau within the brain and slows the progression of tauopathy-induced behavioral impairments. Thus, clearance of neurofibrillary tangles and/or their precursors may reduce synaptic and neuronal loss associated with AD and other tauopathies. So far the mechanisms involved in antibody-mediated clearance of tau pathology are yet to be elucidated. In this study we have used a mouse brain slice model to examine the uptake and localization of FITC labeled anti-tau antibodies. Confocal microscopy analysis showed that the FITC labeled anti-tau antibody co-stained with phosphorylated tau, had a perinuclear appearance and co-localized with markers of the endosomal/lysosomal pathway. Additionally, tau and FITC-IgG were found together in an enriched lysosome fraction. In summary, antibody-mediated clearance of intracellular tau aggregates appears to occur via the lysosomal pathway.

No MeSH data available.


Related in: MedlinePlus