A model of mucopolysaccharidosis type IIIB in pigs

Mucopolysaccharidosis type IIIB (MPS IIIB) is a rare genetic disorder caused by loss-of-function mutations in the NAGLU gene. Pigs are an ideal large-animal model for human diseases; however, a porcine model of MPS IIIB has not been reported. We have previously generated a heterozygous NAGLU-deficient (NAGLU+/−) Large White boar via a transgenic approach. Here we characterized phenotypes of the F1 offspring of this founder to establish a pig model for MPS IIIB. qRT-PCR revealed that the NAGLU expression level was significantly decreased in a variety of tissues in NAGLU+/− pigs. ELISA assays showed obvious deficiency of NAGLU and higher (P<0.05) glycosaminoglycan levels in multiple tissues from NAGLU+/− pigs. NAGLU+/− pigs grew at a significantly (P<0.05) slower rate than control animals (NAGLU+/+). Death, mostly sudden death, occurred at all ages in NAGLU+/− pigs, most of which died within two years. Necropsy findings included pleural adhesions, lung shrinkage and abnormalities in the pericardium and mild hepatomegaly in NAGLU+/− pigs. Notable pathological changes were observed in the sections of brain, liver, spleen and kidney from NAGLU+/− pigs. Brain atrophy, ventriculomegaly, cerebellar atrophy and abnormalities in the intracerebral capsule, parietal lobes and the thalamus were also evident in NAGLU+/− pigs. Together, NAGLU+/− pigs show typical symptoms of human MPS IIIB patients and thus represent a novel large-animal model for the disease.