Division of Liver and Pancreas Transplantation, Dumont-UCLA Transplantation Center, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Department of Anesthesiology, McGovern Medical School at UTHealth, Houston, TX 77030, USA.
Sci Transl Med. 2023 Aug 2;15(707):eadf2059. doi: 10.1126/scitranslmed.adf2059.
Although alternative splicing (AS) drives transcriptional responses and cellular adaptation to environmental stresses, its contributions in organ transplantation have not been appreciated. We have shown that carcinoembryonic antigen-related cell adhesion molecule (Ceacam1; ), a transmembrane biliary glycoprotein expressed in epithelial, endothelial, and immune cells, determines donor liver transplant quality. Here, we studied how AS of affects ischemia-reperfusion injury (IRI) in mouse and human livers. We found that the short cytoplasmic isoform increased during early acute and late resolution phases of warm IRI injury in mice. Transfection of Ceacam1-deficient mouse hepatocytes with adenoviral Ceacam1-S mitigated hypoxia-induced loss of cellular adhesion by repressing the Ask1/p-p38 cell death pathway. Nucleic acid-blocking morpholinos, designed to selectively induce Ceacam1-S, protected hepatocyte cultures against temperature-induced stress in vitro. Luciferase and chromatin immunoprecipitation assays identified direct binding of hypoxia-inducible factor-1α (Hif-1α) to the mouse polypyrimidine tract binding protein 1 () promoter region. Dimethyloxalylglycine protected mouse livers from warm IR stress and hepatocellular damage by inhibiting prolyl hydroxylase domain-containing protein 1 and promoting AS of . Last, analysis of 46 human donor liver grafts revealed that positively correlated with pretransplant expression. This also correlated with better transplant outcomes, including reduced , total bilirubin, proinflammatory , cytokines, immune activation markers , and incidence of delayed complications from biliary anastomosis. This translational study identified mouse Hif-1α-controlled AS of , through transcriptional regulation of promoter region, as a functional underpinning of hepatoprotection against IR stress and tissue damage in liver transplantation.
虽然可变剪接（AS）驱动转录反应和细胞适应环境压力，但它在器官移植中的贡献尚未得到重视。我们已经表明，癌胚抗原相关细胞黏附分子（Ceacam1；）是一种在上皮细胞、内皮细胞和免疫细胞中表达的跨膜胆汁糖蛋白，决定了供体肝移植的质量。在这里，我们研究了 AS 对小鼠和人类肝脏缺血再灌注损伤（IRI）的影响。我们发现，在小鼠的温暖 IRI 损伤的早期急性和晚期缓解阶段，短细胞质同工型 增加。用腺病毒 Ceacam1-S 转染 Ceacam1 缺陷型小鼠肝细胞可通过抑制 Ask1/p-p38 细胞死亡途径来减轻缺氧诱导的细胞黏附丧失。为了选择性地诱导 Ceacam1-S，设计了核酸阻断型 morpholino，可保护肝细胞培养物免受体外温度应激。荧光素酶和染色质免疫沉淀实验鉴定了缺氧诱导因子-1α（Hif-1α）与小鼠多嘧啶 tract 结合蛋白 1 () 启动子区域的直接结合。二甲氧酰基甘氨酸通过抑制脯氨酰羟化酶结构域蛋白 1 并促进 AS 的发生，保护小鼠肝脏免受温暖的 IR 应激和肝细胞损伤。最后，分析了 46 例人类供体肝移植的结果表明， 与移植前的 表达呈正相关。这也与更好的移植结果相关，包括降低 、总胆红素、促炎 、细胞因子、免疫激活标志物 ，以及减少胆吻合口延迟并发症的发生率。这项转化研究鉴定了小鼠 Hif-1α 控制的 AS ，通过转录调节 启动子区域，作为肝脏移植中 IR 应激和组织损伤的肝保护的功能基础。
