• Background: IDUA encodes lysosomal α-L-iduronidase, which hydrolyzes terminal α-L-iduronic acid residues of dermatan sulfate and heparan sulfate to prevent glycosaminoglycan (GAG) accumulation and maintain cellular homeostasis. The W392X nonsense mutation abolishes IDUA activity, causing severe Hurler syndrome (MPS I-H). Hallmark phenotypes include systemic GAG buildup, skeletal dysplasia, multi-organ damage (cardiopathy, hepatosplenomegaly, corneal opacity), and progressive neurodegeneration.
• Targeting strategy: A mutation p.W401X, c.TGG>TAG was introduced into the mouse Idua gene in B-NDG Idua*W392X mice.
• Validation: Activity of IDUA enzyme in the liver and heart tissues of B-NDG Idua*W392X mice was much lower than that of wild-type B-NDG mice.
• Application: B-NDG Idua*W392X mice is a disease model of Mucopolysaccharidosis type I (MPS I, also known as Hurler syndrome), a lysosomal storage disorder, caused by the deficiency of the lysosomal enzyme α-L-iduronidase (IDUA).

Gene targeting strategy for B-NDG Idua*W392X mice.

A mutation p.W401X, c.TGG>TAG was introduced into the mouse Idua gene in B-NDG Idua*W392X mice.

IDUA Enzyme Activity Detection in B-NDG Idua*W392X mice. The liver and heart tissues were collected from wild-type B-NDG mice and homozygous B-NDG Idua*W392X mice (male, 10-week-old, n=3), and IDUA enzyme activity was detected using 4-Methyl-umbelliferyl-α-L-iduronide (4-MU-IdoA) fluorogenic substrate assay. The results showed that the activity of IDUA enzyme in the liver and heart tissues of B-NDG Idua*W392X mice was much lower than that of wild-type B-NDG mice. Values are expressed as mean ± SEM. Significance was determined by unpaired t-test.  *P < 0.05, **P < 0.01, ***P < 0.001.

IDUA Enzyme Activity Detection in B-NDG Idua*W392X mice. The serum, liver and heart tissues were collected from wild-type B-NDG mice and homozygous B-NDG Idua*W392X mice (female, 6-week-old, n=3), and IDUA enzyme activity was detected using 4-Methyl-umbelliferyl-α-L-iduronide (4-MU-IdoA) fluorogenic substrate assay. The results showed that the activity of IDUA enzyme in the serum, liver and heart tissues of B-NDG Idua*W392X mice was much lower than that of wild-type B-NDG mice. Values are expressed as mean ± SEM. Significance was determined by unpaired t-test.  *P < 0.05, **P < 0.01, ***P < 0.001.

Sulfated glycosaminoglycans (sGAG) Detection in B-NDG Idua*W392X mice. The liver and heart tissues were collected from wild-type B-NDG mice and homozygous B-NDG Idua*W392X mice (female, 6-week-old, n=3), and IDUA enzyme activity was detected using Blyscan Sulfated Glycosaminoglycan Assay Reagent. The results showed that sGAG level in the liver and heart tissues of B-NDG Idua*W392X mice was much higher than that of wild-type B-NDG mice. Values are expressed as mean ± SEM. Significance was determined by unpaired t-test.  *P < 0.05, **P < 0.01, ***P < 0.001.