Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, Shanghai, China; Shanghai Institute of Pancreatic Diseases, Shanghai, China.
Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, Shanghai, China; Shanghai Institute of Pancreatic Diseases, Shanghai, China.
Cell Mol Gastroenterol Hepatol. 2022;14(1):55-74. doi: 10.1016/j.jcmgh.2022.03.013. Epub 2022 Apr 7.
BACKGROUND & AIMS: A hybrid allele that originated from homologous recombination between CEL and its pseudogene (CELP), CEL-HYB1 increases the risk of chronic pancreatitis (CP). Although suggested to cause digestive enzyme misfolding, definitive in vivo evidence for this postulate has been lacking.
CRISPR-Cas9 was used to generate humanized mice harboring the CEL-HYB1 allele on a C57BL/6J background. Humanized CEL mice and C57BL/6J mice were used as controls. Pancreata were collected and analyzed by histology, immunohistochemistry, immunoblotting, and transcriptomics. Isolated pancreatic acini were cultured in vitro to measure the secretion and aggregation of CEL-HYB1 protein. Mice were given caerulein injections to induce acute pancreatitis (AP) and CP.
Pancreata from mice expressing CEL-HYB1 developed pathological features characteristic of focal pancreatitis that included acinar atrophy and vacuolization, inflammatory infiltrates, and fibrosis in a time-dependent manner. CEL-HYB1 expression in pancreatic acini led to decreased secretion and increased intracellular aggregation and triggered endoplasmic reticulum stress compared with CEL. The autophagy levels of pancreata from mice expressing CEL-HYB1 changed at different developmental stages; some aged CEL-HYB1 mice exhibited an accumulation of large autophagic vesicles and impaired autophagy in acinar cells. Administration of caerulein increased the severity of AP/CP in mice expressing CEL-HYB1 compared with control mice, accompanied by higher levels of endoplasmic reticulum stress.
Expression of a humanized form of CEL-HYB1 in mice promotes endoplasmic reticulum stress and pancreatitis through a misfolding-dependent pathway. Impaired autophagy appears to be involved in the pancreatic injury in aged CEL-HYB1 mice. These mice have the potential to be used as a model to identify therapeutic targets for CP.
一种源自 CEL 与其假基因（CELP）之间同源重组的杂合子 CEL-HYB1 增加了慢性胰腺炎（CP）的风险。尽管该杂合子被认为导致消化酶错误折叠，但缺乏该假说的确凿体内证据。
使用 CRISPR-Cas9 在 C57BL/6J 背景下生成携带 CEL-HYB1 等位基因的人源化小鼠。将人源化 CEL 小鼠和 C57BL/6J 小鼠作为对照。收集胰腺并进行组织学、免疫组织化学、免疫印迹和转录组学分析。分离的胰腺腺泡在体外培养以测量 CEL-HYB1 蛋白的分泌和聚集。给小鼠注射 caerulein 诱导急性胰腺炎（AP）和 CP。
表达 CEL-HYB1 的小鼠的胰腺表现出局灶性胰腺炎的特征性病理特征，包括腺泡萎缩和空泡化、炎症浸润和纤维化，呈时间依赖性。与 CEL 相比，胰腺腺泡中 CEL-HYB1 的表达导致分泌减少和细胞内聚集增加，并引发内质网应激。表达 CEL-HYB1 的胰腺的自噬水平在不同的发育阶段发生变化；一些老年 CEL-HYB1 小鼠表现出大量自噬小泡的积累和腺泡细胞中自噬受损。与对照小鼠相比，表达 CEL-HYB1 的小鼠给予 caerulein 后，AP/CP 的严重程度增加，伴随着内质网应激水平的升高。
在小鼠中表达人源化形式的 CEL-HYB1 通过依赖错误折叠的途径促进内质网应激和胰腺炎。在老年 CEL-HYB1 小鼠中，自噬受损似乎参与了胰腺损伤。这些小鼠有可能被用作鉴定 CP 治疗靶点的模型。
