Wilson Sierra R, Delgado Evan R, Alencastro Frances, Loewenstein Rosa L, Leek Madeleine P, Peters Leah R, Kamel Kerollos, Wilkinson Patrick D, Jain Siddhi, Locker Joseph, Liu Silvia, Bhushan Bharat, Duncan Andrew W
Department of Pathology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA.
McGowan Institute for Regenerative Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA.
bioRxiv. 2025 Aug 2:2025.07.31.667940. doi: 10.1101/2025.07.31.667940.
BACKGROUND & AIMS: The liver contains both diploid and polyploid hepatocytes, but their functional differences remain poorly understood. Emerging evidence suggests that each ploidy state contributes to regeneration in an injury-specific manner. We hypothesized that diploid hepatocytes promote healing after acetaminophen (APAP)-induced liver injury.
APPROACH & RESULTS: To study ploidy populations , we utilized mice with a lifelong liver-specific knockout of / (LKO), which are enriched in diploid hepatocytes (>70%) but otherwise normal. Control and LKO mice were treated with APAP (300 or 600 mg/kg), and injury was assessed over 0-96 hours. Although both groups sustained injury, LKO mice showed improved survival, lower serum liver enzyme levels, and reduced necrosis and DNA fragmentation, indicating resistance to APAP-induced injury. To determine if resistance was due to loss or increased diploidy, we deleted in adult hepatocytes (HKO), a model that does not alter ploidy. Injury was similar between controls and HKO, ruling out gene deletion as the protective factor. Transcriptomic and protein analyses revealed minimal baseline differences; however, following APAP treatment, LKO livers exhibited reduced JNK activation and less mitochondrial injury. Finally, APAP-treated wild-type hepatocytes exhibited a shift toward lower ploidy, supporting the idea that diploid cells are more resistant to injury.
Diploid hepatocytes resist APAP-induced liver injury through reduced JNK activation and mitochondrial damage. These findings highlight hepatocyte ploidy as a key determinant of injury response and suggest a protective role for diploid hepatocytes in promoting liver resilience and regeneration.
肝脏中同时存在二倍体和多倍体肝细胞，但其功能差异仍知之甚少。新出现的证据表明，每种倍性状态以损伤特异性方式促进肝脏再生。我们假设二倍体肝细胞可促进对乙酰氨基酚（APAP）诱导的肝损伤后的愈合。
为了研究倍性群体，我们利用了/（LKO）基因在肝脏中终身特异性敲除的小鼠，这些小鼠富含二倍体肝细胞（>70%），但其他方面正常。将对照小鼠和LKO小鼠用APAP（300或600mg/kg）处理，并在0 - 96小时内评估损伤情况。尽管两组均遭受损伤，但LKO小鼠的存活率提高、血清肝酶水平降低、坏死和DNA片段化减少，表明对APAP诱导的损伤具有抗性。为了确定抗性是否是由于二倍体缺失或增加所致，我们在成年肝细胞中删除了（HKO），该模型不会改变倍性。对照小鼠和HKO小鼠的损伤情况相似，排除了基因缺失作为保护因素的可能性。转录组学和蛋白质分析显示基线差异极小；然而，在APAP处理后，LKO肝脏中JNK激活减少，线粒体损伤减轻。最后，经APAP处理的野生型肝细胞呈现出向更低倍性的转变，支持二倍体细胞对损伤更具抗性的观点。
二倍体肝细胞通过减少JNK激活和线粒体损伤来抵抗APAP诱导的肝损伤。这些发现突出了肝细胞倍性是损伤反应的关键决定因素，并表明二倍体肝细胞在促进肝脏恢复力和再生方面具有保护作用。
