NVS1.1

NVS1.1 is an orally active, blood-brain barrier-penetrant eRF1 degrader. NVS1.1 induces ubiquitination of eRF1 at Lys279, mediates proteasomal degradation via the E3 ubiquitin ligases RNF14 and RNF25 as well as the translational stress sensor GCN1, traps eRF1 at the ribosomal A-site, inhibits translation termination and triggers ribosome collision. As a readthrough enhancer, NVS1.1 enables near-cognate tRNA incorporation at premature termination codons by reducing intracellular eRF1 levels. NVS1.1 activates ribosome-associated quality control pathways via ribosome collision, including ubiquitination of small subunit ribosomal proteins. NVS1.1 restores functional full-length CFTR and IDUA proteins and reduces glycosaminoglycan accumulation in relevant models. NVS1.1 can be used in the research of cystic fibrosis and Hurler syndrome (mucopolysaccharidosis type I, MPS I) ^[1].

In Vivo, NVS1.1 (20-40 mg/kg; p.o.; daily; 14 days) restores ~1% wild-type IDUA activity and reduces brain GAG levels by up to 57% in a rat model of Hurler syndrome^[1].

In Vitro, NVS1.1 (1-10 μM; 48 h) dose-dependently restores functional IDUA enzymatic activity in HEKR4 cells expressing the IDUAQ70X or IDUAW402X nonsense mutations^[1]. NVS1.1 (0.1-10 μM for 7 days, 0-0.6 μM for 7 weeks) dose-dependently restores IDUA activity, reduces GAG accumulation, normalizes GUSB activity, and is accompanied by eRF1 depletion in primary fibroblasts from homozygous IDUAW402X Hurler syndrome patients^[1]. NVS1.1 (0.00-5.00 μM; 8-24 h) increases the level of IDUA-W402X mRNA in primary fibroblasts from Hurler syndrome patients^[1]. NVS1.1 (2.5 μM; 6 h) induces proteasomal degradation of eRF1 in HEKR4 PTC reporter cells, and this degradation process does not require neddylation modification of Cullin-RING ligases^[1]. NVS1.1 (25 μM; 30 min) induces ubiquitination modification of eRF1 in HeLa and HEKR4 PTC cells^[1]. The process by which NVS1.1 (0.00-2.5 μM; 6 h) induces eRF1 degradation in HEKR4 PTC reporter cells requires the catalytically active E3 ubiquitin ligases RNF14 and RNF25^[1]. The nonsense codon readthrough-inducing effect of NVS1.1 (0.1-10 μM; 24 h) in HEKR4 PTC reporter cells depends on catalytically active RNF14 and RNF25^[1]. NVS1.1 (2.5 μM; 6 h) requires GCN1 to induce the degradation of eRF1 in HEKR4 cells^[1].

References:
[1]. Gurzeler LA, et al. Drug-induced eRF1 degradation promotes readthrough and reveals a new branch of ribosome quality control. Cell reports. 2023 Sep 26;42(9):113056.