Background : Maple syrup urine disease (MSUD) is a rare autosomal recessive metabolic disorder. It can result in neonatal death due to the accumulation of branched-chain amino acids (BCAA) in the blood. Currently, the treatment for MSUD involves a lifelong low-protein diet and peritoneal dialysis, which are challenging to maintain, and neurological symptoms persist. It is suggested that the utilization of mouse chemically derived hepatic progenitors (mCdHs) could significantly contribute to the development of a fundamental treatment. To achieve this, it is imperative to initially characterize MSUD and establish autologous mCdHs from neonatal mice.

Methods : BCKDHA(Branched chain keto acid dehydrogenase α) +/-mice were obtained from the Canadian Mouse Mutant Repository (CMMR) and bred to generate BCKDHA-/-mice with a 266-bp deletion on Chromosome 7. For characterization, BCAA concentrations were measured from plasma, and BCKDHA mRNA expression levels were assessed. BCKDHA-/-mouse-derived mCdHs were generated by HGF, A83-01 and CHIR99021 from mouse primary hepatocytes(mPHs) isolated using MACS with an E-cadherin antibody.

Results : We observed that BCKDHA-/-mice had a survival rate of less than 12 days after birth. Additionally, we detected significantly increased BCAA concentrations and decreased BCKDHA mRNA expression levels in BCKDHA-/- mice. Due to the low survival rate, we isolated mPHs from postnatal day 7 and successfully established BCKDHA-/-mouse-derived mCdHs.

Conclusions : It is suggested that these established mCdHs could be utilized for gene editing and ex-vivo therapy. Furthermore, it is proposed that transplantation of edited mCdHs could provide a potential therapeutic approach for the treatment of MSUD.