Piccolo, P. | bioRxiv Science

bioRxiv2026

Single-vector AAV delivery of En-ISPmu1 and donor DNA for in vivo targeted genome integration

TnpBs are compact RNA-guided nucleases ideally suited for in vivo delivery. By screening novel TnpBs identified from large metagenomic datasets, ISPmu1 was discovered and its protein and {omega}RNA were engineered to generate En-ISPmu1, which achieved editing efficiencies exceeding 65% across 12 human loci. Owing to its compact size, En-ISPmu1 was delivered together with a donor DNA in a single AAV vector, yielding up to 12.7% targeted integration in mouse liver. These findings establish En-ISPmu1 as a promising versatile platform for in vivo therapeutic genome editing applications.

bioengineering↗

bioRxiv2020

CHOP-c-JUN complex plays a critical role in liver proteotoxicity induced by mutant Z alpha-1 antitrypsin.

Alpha-1 antitrypsin (AAT) deficiency is a common genetic disorder with lung and liver involvement. Most patients carry the Z allele in SERPINA1 that encodes a mutant AAT (ATZ) forming hepatotoxic polymers. We found CHOP upregulation and activation in both mouse (PiZ) and human livers expressing ATZ. Compared to controls, juvenile PiZ/Chop-/- mice showed reduction in hepatic ATZ and transcriptional response to endoplasmic reticulum stress, as consequence of CHOP-mediated increase of SERPINA1 transcription. CHOP was found to upregulate SERPINA1 though binding with c-JUN on SERPINA1 regulatory elements, thus aggravating hepatic accumulation of ATZ. Increased CHOP levels were detected in diseased livers of children homozygous for the Z allele. Compared to adults, AAT deficiency in infants has different severity and prognosis. Based on our findings, CHOP-c-JUN complex upregulates SERPINA1 transcription and play an important role in the hepatic disease pathogenesis by increasing the burden of proteotoxic ATZ, particularly in the pediatric population.

genetics↗