Inhibition of prolyl oligopeptidase: A promising pathway to prevent the progression of age-related macular degeneration

Nonpeptidic Oxazole-Based Prolyl Oligopeptidase Ligands with Disease-Modifying Effects on α-Synuclein Mouse Models of Parkinson’s Disease

“…Proteasomal inhibitors, lactacystin (10 μM) and MG-132 (10 μM), were used as positive controls to induce αSyn dimerization, and KYP-2047 (10 μM) was used as a reference PREP ligand. Oxazoles were used at 10 μM concentrations based on earlier studies. , KYP-2047, which has been shown to reduce αSyn aggregation in cells and in vivo , reduces the luminescence signal to 87% of the DMSO control in this assay, and based on this, a compound reducing the signal to this level can be considered active. Compounds 15 , 22 , and 26 were the most effective ones, decreasing the signal to at least 75% compared to the control, and compounds HUP-55 , 4 , 7 , 8 , 13 , and 30 were also more effective than the reference compound KYP-2047 (not significantly), decreasing the signal to 80–85% compared to the control.…”

“…Target engagement was tested using the cellular thermal shift assay (CETSA; Figure A). Ten micromolar HUP-55 caused a 3.01 °C increase in the fitted mean aggregation temperatures (DMSO: 50.18 °C; HUP-55: 53.19 °C), which is similar to the results of PREP inhibitors tested in the study by Hellinen et al., indicating an interaction between HUP-55 and PREP. The specificity of HUP-55 was tested on close-relative enzyme fibroblast activating protein (FAP) and dipeptidyl peptidase (DPP) 2, 4, and 9, but no inhibition of these enzymes was seen with 1 or 10 μM doses (Figure B).…”

“…Bafilomycin A1 (20 nM) was used as an autophagy inhibitor, while rapamycin (500 nM) and serum starvation served as positive controls for autophagy induction. Oxazoles were used at 10 μM concentrations based on earlier studies 17 , 41 and KYP-2047 (10 μM) was used as a reference. It should be noted that in this assay, even a small decrease in the GFP signal indicates an increased autophagic flux as 500 nM rapamycin, a classical autophagy activator via mammalian target of rapamycin (mTOR) inhibition, decreased the signal to 65% of the DMSO control.…”

“…CETSA was performed as previously described . HEK-293 cells were seeded to T25 flasks with a density of 1 × 10 6 cells.…”

Therapeutic Effect of Prolyl Endopeptidase Inhibitor in High-fat Diet-induced Metabolic Dysfunction-associated Fatty Liver Disease

“…Numerous studies have suggested that PREP is a negative regulator of autophagy, and PREP inhibition or knockout can improve a series of human diseases by enhancing autophagy. 6,16,[43][44][45] Notably, impaired autophagy is associated with the development of MAFLD. [46][47][48] We hypothesized that the PREP inhibitor, KYP-2047, contributes to the improvement of MAFLD by regulating autophagy.…”