Enhancing genome editing in hPSCs through dual inhibition of DNA damage response and repair pathways.

Precise genome editing is crucial for establishing isogenic human disease models and ex vivo stem cell therapy from the patient-derived hPSCs. Unlike Cas9-mediated knock-in, cytosine base editor and prime editor achieve the desirable gene correction without inducing DNA double strand breaks. However, hPSCs possess highly active DNA repair pathways and are particularly susceptible to p53-dependent cell death. These unique characteristics impede the efficiency of gene editing in hPSCs. Here, we demonstrate that dual inhibition of p53-mediated cell death and distinct activation of the DNA damage repair system upon DNA damage by cytosine base editor or prime editor additively enhanced editing efficiency in hPSCs. The BE4stem system comprised of p53DD, a dominant negative p53, and three UNG inhibitor, engineered to specifically diminish base excision repair, improves cytosine base editor efficiency in hPSCs. Addition of dominant negative MLH1 to inhibit mismatch repair activity and p53DD in the conventional prime editor system also significantly enhances prime editor efficiency in hPSCs. Thus, combined inhibition of the distinct cellular cascades engaged in hPSCs upon gene editing could significantly enhance precise genome editing in these cells.

Risk factors affecting severe thoracic injuries in motor vehicle collisions based on age group and collision directions.

OBJECTIVE: This study aimed to investigate the effect of age and collision direction on the severity of thoracic injuries based on a real-world crash database. METHODS: This was a retrospective, observational study. We used the Korean In-Depth Accident Study (KIDAS) database, which was collected from crash injury patients who visited emergency medical centers between January 2011 and February 2022 in Korea. Among the 4520 patients enrolled in the database, we selected 1908 adult patients with abbreviated injury scale (AIS) scores between 0 and 6 in the thoracic region. We classified patients with an AIS score of 3 or higher into the severe injury group. RESULTS: The incidence rate of severe thoracic injuries due to motor vehicle accidents was 16.4%. Between the severe and non-severe thoracic injury groups, there were significant differences in sex, age, collision direction, crash object, seatbelt use, and delta-V parameters. Among the age groups, over 55 years occupants had a higher risk in the thoracic regions than those under 54 years occupants. The risk of severe thoracic injury was highest in near-side collisions in all collision directions. Far-side and rear-end collisions showed a lower risk than frontal collisions. Occupants with unfastened seatbelts were at greater risk. CONCLUSIONS: The risk of severe thoracic injury is high in near-side collisions among elderly occupants. However, the risk of injury for elderly occupants increases in a super-aging society. To reduce thoracic injury, safety features made for elderly occupants in near-side collisions are required.