Using tail-vein hydrodynamic-based delivery of NmeCas9 plasmid to target the Hpd gene, we successfully reprogram the tyrosine degradation pathway in Hereditary Tyrosinemia Type I mice.
We observed long-term postnatal persistence of edited cells in both models, with reduction of plasma PCSK9 and cholesterol levels following in utero Pcsk9 targeting and rescue of the lethal phenotype of hereditary tyrosinemia type 1 following in utero Hpd targeting.
4-Hydroxyphenylpyruvate dioxygenase (HPPD), converting phydroxyphenylpyruvate (HPPA) to homogentisate (HGA), is an important target for treating type I tyrosinemia and synthesizing novel herbicides due to its significant role in tyrosine catabolism.
The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrolase which functions downstream of HPD in the tyrosine degradation pathway, is often associated with decreased expression of HPD, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia.