Inhibition of Tau Protein Aggregation by Rhodanine-based Compounds Solubilized Via Specific Formulation Additives to Improve Bioavailability and Cell Viability.
Anti-aggregation drugs play an important role in therapeutic approaches for Alzheimer's disease. We have previously developed a number of compounds that are able to inhibit the pathological aggregation of Tau protein. One common obstacle to application is the limited penetration across the plasma membranes into cells, where Tau aggregation occurs in the cytosol. We used an inducible N2a cell line which expresses the repeat domain of tau and develops tau aggregates.



Several peptide-polymer conjugates were synthesized to enhance the uptake of compounds into cells and thus to improve their biomedical application. The aim of this study was to test whether the peptide-inhibitor complexes still retain their inhibitory activity on Tau aggregation.



We screened peptide sequences with high binding capacity to a subset of aggregation inhibitors and identified them by fluorescence microscopy and MALDI MS/MS with regard to drug solubility and effective complexion. To explore whether the synthesized complexes can influence the aggregation propensity of Tau we performed in vitro and cellular assays. The effect on toxicity was investigated by measuring apoptosis markers.



The tested peptide-compound complexes show no decrease in the total Tau levels but decreased ratios of soluble to pelletable Tau species. This indicates a conversion of insoluble Tau oligomers into soluble forms which appear to be less toxic than the insoluble ones, as seen by a decrease of apoptotic cells. Thus the peptide-compound complexes have a higher potency than the compounds alone due to improved bioavailability of the drug.
Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn. Germany.
Marcus
M
Pickhardt
Department of Chemistry, Laboratory for Organic Synthesis of Functional Systems, Humboldt-Universitat zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin. Germany.
Carmen
C
Lawatscheck
Department of Chemistry, Laboratory for Organic Synthesis of Functional Systems, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin. Germany.
Hans G
HG
Borner
CAESAR Research Institute, Ludwig- Erhard-Allee, 2, 53175; Max-Planck-Institute for Metabolism Research, Gleuerlerstr. 50, 50931 Koln. Germany.
Eckhard
E
Mandelkow
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D001682:Biological Availability; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D051379:Mice; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D019151:Peptide Library; D010455:Peptides / Q000494:pharmacology; D066329:Protein Aggregates / Q000187:drug effects*; D012236:Rhodanine / Q000737:chemistry* / Q000493:pharmacokinetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014162:Transfection; D019680:Trinucleotide Repeat Expansion / Q000235:genetics; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
D017304:Annexin A5; D019151:Peptide Library; D010455:Peptides; D066329:Protein Aggregates; D016875:tau Proteins; D012236:Rhodanine
Alzheimer's disease; Tau protein; aggregation modulator; bioconjugates; cell model; combinatorial screening; rhodanine