Oligomer modulator anle138b and related compounds in neurodegeneration and beyond

Abstract

cell-based model, compound anle138b shows the highest anti-prion activity against various prion stains, including RML, sCJD and vCJD. On the basis of the results from the SIFT, cell culture and PMCA assay, 38 DPP-related compounds were tested in vivo in RML prioninfected mice model. Following oral administration, anle138b and other DPP compounds strongly inhibited the accumulation of PrP Sc , neuronal degeneration and disease progression.Regarding the mode of action of anle138b, several lines of evidences from in vitro and in vivo studies support the mechanism associated with direct modulation of prion protein aggregation at the oligomer level.The second part of my thesis describes the property of selected DPP compounds to interfere with α-synuclein aggregation and toxicity. Here, we conducted the SIFT screening assay on α-synuclein. We were able to identify a set of highly potent inhibitors of α-synuclein aggregation and, moreover, we performed a detailed analysis of structure-activity relationships within our focused library of DPP compounds. Next, the molecular mechanism underlying the modulation of α-synuclein misfolding by DPP compounds was studied by various biochemical and biophysical approaches. By using ThioT aggregation assay, electron microscopy, atomic force microscopy and dynamic light scattering, we showed that watersoluble compounds (sery166a, anle138c, anle145c, sery139 and others) prevent fibrillization of α-synuclein in vitro by stabilization of small globular heterogeneous oligomeric species.CD data suggests that sery166a stabilizes α-synuclein in predominantly unfolded conformation accompanied a low degree of local secondary structure ordering in comparison to the monomeric α-synuclein. To elucidate the mode of inhibition, we applied a highresolution NMR spectroscopy. HSQC-based NMR binding studies showed a lack of direct binding of all tested compounds to monomeric α-synuclein. By using STD NMR experiments, we demonstrated that the DPP compounds preferentially interact with oligomeric species, while the affinity to monomeric α-synuclein is weak. It's, therefore, envisioned that the mechanism of aggregation inhibition by DPP compounds might be associated with the interactions between small ligands and oligomeric forms that, in turn, lead to stabilization of specific off-pathway oligomers and, ultimately, blocking of the fibril formation.Considering that the oligomer-induced membrane permeabilization represents a potential toxicity mechanism associated with α-synuclein misfolding, we investigated DPP compounds and compound-stabilized α-synuclein oligomers using electrophysiological studies in planar lipid bilayers. Our analysis of the electrophysiological data reveals that DPP compound-stabilized oligomers do not adversely affect the membrane stability. Remarkably, Summary 1. Introduction * PINK1 may abolish the kinase activity and, consequently, the protective function. To corroborate this theory two PINK1 substrates were identified: TNF receptor-associated protein 1 83 (TRAP1) and mitochondri...