Table 1.
Treatment groups of mice for the in vivo study.
Fig 1.
The SEE-Tx® methodology uses a structure-based approach to discover non-competitive pharmacological allosteric regulators of alpha-L-iduronidase (IDUA).
Self-explanatory graphic of the procedure used to discover new allosteric regulators for alpha-L-iduronidase.
Fig 2.
Binding of small molecule hit compounds to rhIDUA as determined by DSF.
Difference in melting temperature (ΔTm) relative to rhIDUA in the presence of the compounds #1 to #21 at 30 μM. The mean ΔTm values ± standard deviations are from 2 independent experiments (n = 2). Most compounds have a shift in Tm relative to the baseline suggesting protein stabilization. The dotted line shows the threshold value for the DSF screening, and it was ΔTm ≥ 0.5ºC.
Fig 3.
Chemical structure of hit compound #18 (GT-01803).
Fig 4.
Differential scanning fluorimetry curve shows the thermal shift of recombinant human alpha-L-iduronidase (rhIDUA) with increasing doses of compound GT-01803.
Dose-dependent effect on thermal stability of alpha-L-iduronidase (rhIDUA) in the presence of compound #18 (GT-01803). The mean ΔTm values ± standard deviations are from 2 independent experiments (n = 2).
Fig 5.
Isothermal denaturation assay to determine ligand-induced stabilisation of recombinant human alpha-L-iduronidase (rhIDUA) by GT-01803 (30 μM) at 37 °C.
The percentage of IDUA folded values ± standard errors of the mean are from 2 independent experiments (n = 2). The best-fit value for the half-life of rhIDUA in the absence and presence of the compound was determined using GraphPad Prism software.
Fig 6.
IDUA cell activity following co-administration of rhIDUA without or with 50 μM GT-01803.
(A) at different concentrations of rhIDUA in Hurler-Scheie (GM02845) fibroblasts at 96 h; (B) in Hurler (GM00798) and Hurler/Scheie (GM02845, GM00512, GM01898, GM00963) patient-derived fibroblasts at 96 h; and (C) in Hurler-Scheie fibroblasts (GM02845) at increasing incubation times. Individual values of IDUA activity (nmol/h·mg) are represented in the graphs. Repeated Measured Two-way ANOVA with the Geisser-Greenhouse correction and Šídák’s multiple comparisons test were used to compare the groups. Statistically significant differences are represented *p≤0.05; **p≤0.01 ***p≤0.001; ****p≤0.0001. h, hours.
Fig 7.
Mean plasma concentration-time profiles data of GT-01803.
Plasma pharmacokinetics parameters are calculated using the non-compartmental analysis tool of Phoenix WinNonlin (Version 7.0) following single intravenous (i.v.) and oral (p.o.) administration doses in male C57BL/6 mice.
Table 2.
Plasma pharmacokinetic parameters of GT-01803 following a single intravenous (i.v.) and oral (p.o.) dose administration to C57BL/6 mice.
Fig 8.
Enzymatic activity of rhIDUA with or without GT-01803 in plasma (A) and in bone marrow (B). (A) mice administered with rhIDUA + vehicle (black circles) and rhIDUA + GT-01803 (at 5 mg/kg, 10 mg/kg and 20 mg/kg i.v. q.d.) (blue square, triangle, and rhombus, respectively), in plasma at 0.5, 1 and 2 h after treatment with GT-01803. (B) untreated naïve control mice (grey bar), mice administered with rhIDUA + vehicle (black bars) and rhIDUA + GT-01803 (at 5 mg/kg, 10 mg/kg and 20 mg/kg i.v. q.d.) (blue bars), in bone marrow at 6, 8 and 10 h after treatment with GT-01803. Data expressed as mean ± SEM, n = 6.; ***p<0.01 vs vehicle-treated mice; Vehicle: NMP (5%) + Solutol HS-15 (5%) + saline solution (45%) + PEG-400 (45%) for GT-01803.