Adjunctive nebulization of Idursulfase to intravenous treatment enhances cardiac proteome adaptations in IDS-KO mice

Mucopolysaccharidosis Type II (MPS-II) is a rare X-linked lysosomal storage disorder, characterized by deficiency of the lysosomal hydrolase iduronate 2-sulphatase (IDS). Cardiac impairments contribute to mortality in patients. Enzyme replacement therapy (ERT) with Idursulfase is a promising treatment for the cardiac dysfunction. We compared the proteome changes following intravenous (IV) with and without adjunct nebulized ERT in IDS-KO mice. Male mice were assigned to 4 groups: 1) WT IV + nebulized saline (WT; n=8); 2) IDS-KO IV + nebulized saline (KO; n=5); 3) IDS-KO IV Idursulfase (1 mg/kg; KO-IV, n=5); 4) IDS-KO IV (1 mg/kg) + nebulized Idursulfase (0.33 mg/mouse; KO-NEB, n=5). Treatments were administered once a week starting at 8 weeks of age and the heart was harvested 12 weeks post-ERT. Mouse heart samples were prepared for global proteomics measurements with Nano-liquid chromatography tandem mass spectrometry (n=3/group; Nano-LC/MS/MS). Global limma moderated F-test analysis identified 928 differently abundant proteins across the four groups. Pairwise Euclidean distances from the IDS-KO were significantly greater for the KO-NEB vs KO-IV group (47.5, 3.7 vs 40.8, 1.1; p < 0.001), showing that adjunct nebulization elicited a more profound proteomic shift than IV alone. The mean z-score compartment analysis revealed that the subcellular compartment protein profile of KO-NEB shifted towards the WT profile, whereas this pattern was less evident in KO-IV. The cluster analysis also revealed treatment-specific and rescue-like protein modules. Overall, our results suggest that adjunctive nebulized Idursulfase ERT enhances the cardiac proteomic changes caused by IV treatment in IDS-KO mice. Proteomics data are available via ProteomeXchange with identifier PXD083242.